{ "course": "Advanced_Software_Engineering", "course_id": "CO3065", "schema_version": "material.v1", "slides": [ { "page_index": 0, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_001.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_001.png", "page_index": 0, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:51:58+07:00" }, "raw_text": "Software Engineering Chapter 1 - Dependable systems Chapter 1 Dependable Systems 1" }, { "page_index": 1, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_002.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_002.png", "page_index": 1, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:03+07:00" }, "raw_text": "Topics covered Software Engineering Dependability properties Sociotechnical systems Redundancy and diversity Dependable processes Formal methods and dependability Chapter 1 Dependable Systems 2" }, { "page_index": 2, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_003.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_003.png", "page_index": 2, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:08+07:00" }, "raw_text": "System dependability Software Engineering For many computer-based systems, the most important system property is the dependability of the system. The dependability of a system reflects the user's degree of trust in that system. It reflects the extent of the user's confidence that it will operate as users expect and that it will not 'fail' in normal use. Dependability covers the related systems attributes of reliability, availability and security. These are all inter- dependent. Chapter 1 Dependable Systems 3" }, { "page_index": 3, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_004.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_004.png", "page_index": 3, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:12+07:00" }, "raw_text": "Importance of dependability Software Engineering System failures may have widespread effects with large numbers of people affected by the failure. Systems that are not dependable and are unreliable unsafe or insecure may be rejected by their users. The costs of system failure may be very high if the failure Ieads to economic losses or physical damage. Undependable systems may cause information loss with a high consequent recovery cost. Chapter 1 Dependable Systems 4" }, { "page_index": 4, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_005.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_005.png", "page_index": 4, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:17+07:00" }, "raw_text": "Causes of failure Software Engineering Hardware failure Hardware fails because of design and manufacturing errors or because components have reached the end of their natural life Software failure Software fails due to errors in its specification, design or implementation. Operational failure Human operators make mistakes. Now perhaps the largest single cause of system failures in socio-technical systems. Chapter 1 Dependable Systems 5" }, { "page_index": 5, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_006.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_006.png", "page_index": 5, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:20+07:00" }, "raw_text": "Software Engineering Dependability properties Chapter 1 Dependable Systems 6" }, { "page_index": 6, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_007.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_007.png", "page_index": 6, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:28+07:00" }, "raw_text": "The principal dependability properties Software Engineering Dependability Availability Reliability Safety Security Resilience The ability of the system The ability of the system The ability of the system The ability of the system The ability of the system to deliver services when to deliver services as to operate without to protect itself against to resist and recover requested specified catastrophic failure deliberate or accidental from damaging events intrusion Chapter 1 Dependable Systems 7" }, { "page_index": 7, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_008.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_008.png", "page_index": 7, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:35+07:00" }, "raw_text": "Principal properties Software Engineering Availability The probability that the system will be up and running and able to deliver useful services to users. Reliability The probability that the system will correctly deliver services as expected by users. Safety A judgment of how likely it is that the system will cause damage to people or its environment. Chapter 1 Dependable Systems 8" }, { "page_index": 8, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_009.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_009.png", "page_index": 8, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:42+07:00" }, "raw_text": "Principal properties Software Engineering Security A judgment of how likely it is that the system can resist accidental or deliberate intrusions Resilience A judgment of how well a system can maintain the continuity of its critical services in the presence of disruptive events such as equipment failure and cyberattacks. Chapter 1 Dependable Systems 9" }, { "page_index": 9, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_010.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_010.png", "page_index": 9, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:50+07:00" }, "raw_text": "Other dependability properties Software Engineering Repairability Reflects the extent to which the system can be repaired in the event of a failure Maintainability Reflects the extent to which the system can be adapted to new requirements; Error tolerance Reflects the extent to which user input errors can be avoided and tolerated. Chapter 1 Dependable Systems 10" }, { "page_index": 10, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_011.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_011.png", "page_index": 10, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:52:56+07:00" }, "raw_text": "Dependability attribute dependencies Software Engineering Safe system operation depends on the system being available and operating reliably A system may be unreliable because its data has been corrupted by an external attack. Denial of service attacks on a system are intended to make it unavailable If a system is infected with a virus, you cannot be confident in its reliability or safety Chapter 1 Dependable Systems 11" }, { "page_index": 11, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_012.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_012.png", "page_index": 11, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:02+07:00" }, "raw_text": "Dependability achievement Software Engineering Avoid the introduction of accidental errors when developing the system. Design processes that are effective in discovering residual errors in the system. Design systems to be fault tolerant so that they can continue in operation when faults occur Design protection mechanisms that guard against external attacks Chapter 1 Dependable Systems 12" }, { "page_index": 12, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_013.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_013.png", "page_index": 12, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:07+07:00" }, "raw_text": "Dependability achievement Software Engineering Configure the system correctly for its operating environment Include system capabilities to recognise and resist cyberattacks. Include recovery mechanisms to help restore normal system service after a failure. Chapter 1 Dependable Systems 13" }, { "page_index": 13, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_014.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_014.png", "page_index": 13, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:14+07:00" }, "raw_text": "Dependability costs Software Engineering Dependability costs tend to increase exponentially as increasing levels of dependability are required. There are two reasons for this The use of more expensive development techniques and hardware that are required to achieve the higher levels of dependability The increased testing and system validation that is reguired to convince the system client and regulators that the required levels of dependability have been achieved. Chapter 1 Dependable Systems 14" }, { "page_index": 14, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_015.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_015.png", "page_index": 14, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:20+07:00" }, "raw_text": "Cost/dependability curve Software Engineering Gost Low Medium High Very Ultra- high high Dependability Chapter 1 Dependable Systems 15" }, { "page_index": 15, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_016.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_016.png", "page_index": 15, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:24+07:00" }, "raw_text": "Dependability economics Software Engineering Because of very high costs of dependability achievement, it may be more cost effective to accept untrustworthy systems and pay for failure costs However, this depends on social and political factors. A reputation for products that can't be trusted may lose future business Depends on system type - for business systems in particular, modest levels of dependability may be adequate Chapter 1 Dependable Systems 16" }, { "page_index": 16, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_017.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_017.png", "page_index": 16, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:27+07:00" }, "raw_text": "Software Engineering Sociotechnical systems Chapter 1 Dependable Systems 17" }, { "page_index": 17, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_018.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_018.png", "page_index": 17, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:36+07:00" }, "raw_text": "Systems and software Software Engineering Software engineering is not an isolated activity but is part of a broader systems engineering process. Software systems are therefore not isolated systems but are essential components of broader systems that have a human, social or organizational purpose. Example The wilderness weather system is part of broader weather recording and forecasting systems These include hardware and software, forecasting processes, system users, the organizations that depend on weather forecasts, etc Chapter 1 Dependable Systems 18" }, { "page_index": 18, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_019.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_019.png", "page_index": 18, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:42+07:00" }, "raw_text": "The sociotechnical systems stack Software Engineering Society Organization Business processes Application system Systems Software engineering engineering Communications and data management Operating system Equipment Chapter 1 Dependable Systems 19" }, { "page_index": 19, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_020.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_020.png", "page_index": 19, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:48+07:00" }, "raw_text": "Layers in the STS stack Software Engineering Equipment Hardware devices, some of which may be computers. Most devices will include an embedded system of some kind. Operating system Provides a set of common facilities for higher levels in the system. Communications and data management Middleware that provides access to remote systems and databases. Application systems Specific functionality to meet some organization requirements. Chapter 1 Dependable Systems 20" }, { "page_index": 20, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_021.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_021.png", "page_index": 20, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:53:55+07:00" }, "raw_text": "Layers in the STS stack Software Engineering Business processes A set of processes involving people and computer systems that support the activities of the business. Organizations Higher level strategic business activities that affect the operation of the system. Society Laws, regulation and culture that affect the operation of the system. Chapter 1 Dependable Systems 21" }, { "page_index": 21, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_022.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_022.png", "page_index": 21, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:01+07:00" }, "raw_text": "Holistic system design Software Engineering There are interactions and dependencies between the layers in a system and changes at one level ripple through the other levels Example: Change in regulations (society) leads to changes in business processes and application software. For dependability, a systems perspective is essential Contain software failures within the enclosing layers of the STS stack. Understand how faults and failures in adjacent layers may affect the software in a system Chapter 1 Dependable Systems 22" }, { "page_index": 22, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_023.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_023.png", "page_index": 22, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:06+07:00" }, "raw_text": "Regulation and compliance Software Engineering The general model of economic organization that is now almost universal in the world is that privately owned companies offer goods and services and make a profit on these To ensure the safety of their citizens, most governments regulate (limit the freedom of) privately owned companies so that they must follow certain standards to ensure that their products are safe and secure. Chapter 1 Dependable Systems 23" }, { "page_index": 23, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_024.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_024.png", "page_index": 23, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:12+07:00" }, "raw_text": "Regulated systems Software Engineering Many critical systems are regulated systems, which means that their use must be approved by an external regulator before the systems go into service. Nuclear systems Air traffic control systems Medical devices A safety and dependability case has to be approved by the regulator. Therefore, critical systems development has to create the evidence to convince a regulator that the system is dependable, safe and secure. Chapter 1 Dependable Systems 24" }, { "page_index": 24, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_025.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_025.png", "page_index": 24, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:19+07:00" }, "raw_text": "Safety regulation Software Engineering Regulation and compliance (following the rules) applies to the sociotechnical system as a whole and not simply the software element of that system. Safety-related systems may have to be certified as safe by the regulator. To achieve certification, companies that are developing safety-critical systems have to produce an extensive safety case that shows that rules and regulations have been followed It can be as expensive develop the documentation for certification as it is to develop the system itself. Chapter 1 Dependable Systems 25" }, { "page_index": 25, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_026.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_026.png", "page_index": 25, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:23+07:00" }, "raw_text": "Software Engineering Redundancy and diversity Chapter 1 Dependable Systems 26" }, { "page_index": 26, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_027.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_027.png", "page_index": 26, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:29+07:00" }, "raw_text": "Redundancy and diversity Software Engineering Redundancy Keep more than a single version of critical components so that if one fails then a backup is available. Diversity Provide the same functionality in different ways in different components so that they will not fail in the same way. Redundant and diverse components should be independent so that they will not suffer from 'common- mode' failures For example, components implemented in different programming languages means that a compiler fault will not affect all of them. Chapter 1 Dependable Systems 27" }, { "page_index": 27, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_028.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_028.png", "page_index": 27, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:35+07:00" }, "raw_text": "Diversity and redundancy examples Software Engineering Redundancy. Where availability is critical (e.g. in e- commerce systems), companies normally keep backup servers and switch to these automatically if failure occurs. Diversity. To provide resilience against external attacks, different servers may be implemented using different operating systems (e.g. Windows and Linux) Chapter 1 Dependable Systems 28" }, { "page_index": 28, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_029.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_029.png", "page_index": 28, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:41+07:00" }, "raw_text": "Process diversity and redundancy Software Engineering Process activities, such as validation, should not depend on a single approach, such as testing, to validate the system. Redundant and diverse process activities are important especially for verification and validation Multiple, different process activities complement each other and allow for cross-checking help to avoid process errors, which may lead to errors in the software. Chapter 1 Dependable Systems 29" }, { "page_index": 29, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_030.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_030.png", "page_index": 29, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:46+07:00" }, "raw_text": "Problems with redundancy and diversity Software Engineering Adding diversity and redundancy to a system increases the system complexity. This can increase the chances of error because of unanticipated interactions and dependencies between the redundant system components. Some engineers therefore advocate simplicity and extensive as a more effective route to software dependability Chapter 1 Dependable Systems 30" }, { "page_index": 30, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_031.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_031.png", "page_index": 30, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:49+07:00" }, "raw_text": "Software Engineering Dependable processes Chapter 1 Dependable Systems 31" }, { "page_index": 31, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_032.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_032.png", "page_index": 31, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:54:55+07:00" }, "raw_text": "Dependable processes Software Engineering Y To ensure a minimal number of software faults, it is important to have a well-defined, repeatable software process. A well-defined repeatable process is one that does not depend entirely on individual skills; rather can be enacted by different people! Regulators use information about the process to check if good software engineering practice has been used. For fault detection, it is clear that the process activities should include significant effort devoted to verification and validation Chapter 1 Dependable Systems 32" }, { "page_index": 32, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_033.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_033.png", "page_index": 32, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:01+07:00" }, "raw_text": "Dependable process characteristics Software Engineering Explicitly defined A process that has a defined process model that is used to drive the software production process. Data must be collected during the process that proves that the development team has followed the process as defined in the process model. Repeatable A process that does not rely on individual interpretation and judgment. The process can be repeated across projects and with different team members, irrespective of who is involved in the development Chapter 1 Dependable Systems 33" }, { "page_index": 33, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_034.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_034.png", "page_index": 33, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:10+07:00" }, "raw_text": "Attributes of dependable processes Software Engineering Process characteristic Description Auditable The process should be understandable by people apart from process participants, who can check that process standards are being followed and make suggestions for process improvement. Diverse The process should include redundant and diverse verification and validation activities Documentable The process should have a defined process model that sets out the activities in the process and the documentation that is to be produced during these activities. Robust The process should be able to recover from failures of individual process activities. Standardized A comprehensive set of software development standards covering 1 software production and documentation should be available Chapter 1 Dependable Systems 34" }, { "page_index": 34, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_035.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_035.png", "page_index": 34, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:17+07:00" }, "raw_text": "Dependable process activities Software Engineering Requirements reviews to check that the requirements are, as far as possible, complete and consistent. Requirements management to ensure that changes to the requirements are controlled and that the impact of proposed requirements changes is understood. Formal specification, where a mathematical model of the software is created and analyzed System modeling, where the software design is explicitly documented as a set of graphical models, and the links between the reguirements and these models are documented Chapter 1 Dependable Systems 35" }, { "page_index": 35, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_036.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_036.png", "page_index": 35, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:23+07:00" }, "raw_text": "Dependable process activities Software Engineering Design and program inspections, where the different descriptions of the system are inspected and checked by different people Static analysis, where automated checks are carried out on the source code of the program. Test planning and management, where a comprehensive set of system tests is designed. The testing process has to be carefully managed to demonstrate that these tests provide coverage of the system requirements and have been correctly applied in the testing process. Chapter 1 Dependable Systems 36" }, { "page_index": 36, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_037.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_037.png", "page_index": 36, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:29+07:00" }, "raw_text": "Dependable processes and agility Software Engineering Dependable software often requires certification so both process and product documentation has to be produced. Up-front requirements analysis is also essential to discover requirements and requirements conflicts that may compromise the safety and security of the system Chapter 1 Dependable Systems 37" }, { "page_index": 37, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_038.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_038.png", "page_index": 37, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:36+07:00" }, "raw_text": "Dependable processes and agility Software Engineering An agile process may be defined that incorporates techniques such as iterative development, test-first development and user involvement in the development team. So long as the team follows that process and documents their actions, agile methods can be used. However, additional documentation and planning is essential so pure agile' is impractical for dependable systems engineering. Chapter 1 Dependable Systems 38" }, { "page_index": 38, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_039.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_039.png", "page_index": 38, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:40+07:00" }, "raw_text": "Software Engineering Formal methods and dependability Chapter 1 Dependable Systems 39" }, { "page_index": 39, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_040.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_040.png", "page_index": 39, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:46+07:00" }, "raw_text": "Formal specification Software Engineering development that are based on mathematical representation and analysis of software. Formal methods include Formal specification; Specification analysis and proof Transformational development: Program verification. Formal methods significantly reduce some types of programming errors and can be cost-effective for dependable systems engineering Chapter 1 Dependable Systems 40" }, { "page_index": 40, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_041.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_041.png", "page_index": 40, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:52+07:00" }, "raw_text": "Formal approaches Software Engineering Verification-based approaches Different representations of a software system such as a specification and a program implementing that specification are proved to be equivalent. This demonstrates the absence of implementation errors. Refinement-based approaches A representation of a system is systematically transformed into another, lower-level representation e.g. a specification is transformed automatically into an implementation. This means that, if the transformation is correct, the representations are equivalent. Chapter 1 Dependable Systems 41" }, { "page_index": 41, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_042.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_042.png", "page_index": 41, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:55:58+07:00" }, "raw_text": "Use of formal methods Software Engineering The principal benefits of formal methods are in reducing the number of faults in systems. Consequently, their main area of applicability is in dependable systems engineering. There have been several successful projects where formal methods have been used in this area. In this area, the use of formal methods is most likely to be cost-effective because high system failure costs must be avoided Chapter 1 Dependable Systems 42" }, { "page_index": 42, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_043.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_043.png", "page_index": 42, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:04+07:00" }, "raw_text": "Classes of error Software Engineering Specification and design errors and omissions Developing and analysing a formal model of the software may reveal errors and omissions in the software requirements. If the model is generated automatically or systematically from source code, analysis using model checking can find undesirable states that may occur such as deadlock in a concurrent system. Inconsistencies between a specification and a program. If a refinement method is used, mistakes made by developers that make the software inconsistent with the specification are avoided. Program proving discovers inconsistencies between a program and its specification. Chapter 1 Dependable Systems 43" }, { "page_index": 43, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_044.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_044.png", "page_index": 43, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:10+07:00" }, "raw_text": "Benefits of formal specification Software Engineering Developing a formal specification reguires the system requirements to be analyzed in detail. This helps to detect problems, inconsistencies and incompleteness in the requirements. As the specification is expressed in a formal language, it can be automatically analyzed to discover inconsistencies and incompleteness. If you use a formal method such as the B method, you can transform the formal specification into a 'correct' program. Program testing costs may be reduced if the program is formally verified against its specification. Chapter 1 Dependable Systems 44" }, { "page_index": 44, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_045.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_045.png", "page_index": 44, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:17+07:00" }, "raw_text": "Acceptance of formal methods Software Engineering Formal methods have had limited impact on practical software development: Problem owners cannot understand a formal specification and so cannot assess if it is an accurate representation of their requirements. It is easy to assess the costs of developing a formal specification but harder to assess the benefits. Managers may therefore be unwilling to invest in formal methods. Software engineers are unfamiliar with this approach and are therefore reluctant to propose the use of FM. Formal methods are still hard to scale up to large systems. Formal specification is not really compatible with agile development methods. Chapter 1 Dependable Systems 45" }, { "page_index": 45, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_046.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_046.png", "page_index": 45, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:22+07:00" }, "raw_text": "Key points Software Engineering System dependability is important because failure of critical systems can lead to economic losses, information Ioss, physical damage or threats to human life. The dependability of a computer system is a system property that reflects the user's degree of trust in the system. The most important dimensions of dependability are availability, reliability, safety, security and resilience. Sociotechnical systems include computer hardware software and people, and are situated within an organization. They are designed to support organizational or business goals and objectives. Chapter 1 Dependable Systems 46" }, { "page_index": 46, "chapter_num": 1, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_047.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_1/slide_047.png", "page_index": 46, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:28+07:00" }, "raw_text": "Key points Software Engineering The use of a dependable, repeatable process is essential if faults in a system are to be minimized. The process should include verification and validation activities at all stages, from requirements definition through to system implementation. The use of redundancy and diversity in hardware software processes and software systems is essential to the development of dependable systems. Formal methods, where a formal model of a system is used as a basis for development help reduce the number of specification and implementation errors in a system. Chapter 1 Dependable Systems 47" }, { "page_index": 47, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_001.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_001.png", "page_index": 47, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:31+07:00" }, "raw_text": "Software Engineering Chapter 2 - Reliability Engineering Chapter 2 Reliability Engineering 1" }, { "page_index": 48, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_002.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_002.png", "page_index": 48, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:36+07:00" }, "raw_text": "Topics covered Software Engineering Availability and reliability Reliability requirements Fault-tolerant architectures Programming for reliability Reliability measurement Chapter 2 Reliability Engineering 2" }, { "page_index": 49, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_003.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_003.png", "page_index": 49, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:41+07:00" }, "raw_text": "Software reliability Software Engineering In general, software customers expect all software to be dependable. However, for non-critical applications, they may be willing to accept some system failures. Some applications (critical systems) have very high reliability requirements and special software engineering techniques may be used to achieve this. Medical systems Telecommunications and power systems Aerospace systems Chapter 2 Reliability Engineering 3" }, { "page_index": 50, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_004.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_004.png", "page_index": 50, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:51+07:00" }, "raw_text": "Faults, errors and failures Software Engineering Term Description Human error or Human behavior that results in the introduction of faults into a system. For example, in the wilderness weather system, a programmer might decide that the mistake way to compute the time for the next transmission is to add 1 hour to the current time. This works except when the transmission time is between 23.00 and midnight (midnight is 00.00 in the 24-hour clock). System fault A characteristic of a software system that can lead to a system error. The fault is the inclusion of the code to add 1 hour to the time of the last transmission, without a check if the time is greater than or equal to 23.00. System error An erroneous system state that can lead to system behavior that is unexpected by system users. The value of transmission time is set incorrectly (to 24.XX rather than 00.XX) when the faulty code is executed. System failure An event that occurs at some point in time when the system does not deliver a service as expected by its users. No weather data is transmitted because the time is invalid. Chapter 2 Reliability Engineering 4" }, { "page_index": 51, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_005.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_005.png", "page_index": 51, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:56:56+07:00" }, "raw_text": "Faults and failures Software Engineering Failures are usually a result of system errors that are derived from faults in the system However, faults do not necessarily result in system errors The erroneous system state resulting from the fault may be transient and corrected' before an error arises The faulty code may never be executed. Errors do not necessarily lead to system failures The error can be corrected by built-in error detection and recovery The failure can be protected against by built-in protection facilities. These may, for example, protect system resources from system errors Chapter 2 Reliability Engineering 5" }, { "page_index": 52, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_006.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_006.png", "page_index": 52, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:03+07:00" }, "raw_text": "Fault management Software Engineering Fault avoidance The system is developed in such a way that human error is avoided and thus system faults are minimised. The development process is organised so that faults in the system are detected and repaired before delivery to the customer. Fault detection Verification and validation technigues are used to discover and remove faults in a system before it is deployed. Fault tolerance The system is designed so that faults in the delivered software do not result in system failure. Chapter 2 Reliability Engineering 6" }, { "page_index": 53, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_007.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_007.png", "page_index": 53, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:09+07:00" }, "raw_text": "Reliability achievement Software Engineering Fault avoidance Development technigues are used that either minimise the possibility of mistakes or trap mistakes before they result in the introduction of system faults. Y Fault detection and removal Verification and validation technigues are used that increase the probability of detecting and correcting errors before the system goes into service. Fault tolerance Run-time techniques are used to ensure that system faults do not result in system errors and/or that system errors do not lead to system failures. Chapter 2 Reliability Engineering 7" }, { "page_index": 54, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_008.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_008.png", "page_index": 54, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:13+07:00" }, "raw_text": "The increasing costs of residual fault removal Software Engineering Many Few Very few Number of residual errors Chapter 2 Reliability Engineering 8" }, { "page_index": 55, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_009.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_009.png", "page_index": 55, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:16+07:00" }, "raw_text": "Software Engineering Availability and reliability Chapter 2 Reliability Engineering 9" }, { "page_index": 56, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_010.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_010.png", "page_index": 56, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:21+07:00" }, "raw_text": "Availability and reliability Software Engineering Reliability The probability of failure-free system operation over a specified time in a given environment for a given purpose Availability The probability that a system, at a point in time, will be operational and able to deliver the requested services Both of these attributes can be expressed quantitatively e.g. availability of 0.999 means that the system is up and running for 99.9% of the time. Chapter 2 Reliability Engineering 10" }, { "page_index": 57, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_011.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_011.png", "page_index": 57, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:27+07:00" }, "raw_text": "Reliability and specifications Software Engineering Reliability can only be defined formally with respect to a system specification i.e. a failure is a deviation from a specification. However, many specifications are incomplete or incorrect - hence, a system that conforms to its specification may 'fail' from the perspective of system users. Furthermore, users don't read specifications so don't know how the system is supposed to behave. Therefore perceived reliability is more important in practice. Chapter 2 Reliability Engineering 11" }, { "page_index": 58, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_012.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_012.png", "page_index": 58, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:33+07:00" }, "raw_text": "Perceptions of reliability Software Engineering The formal definition of reliability does not always reflect the user's perception of a system's reliability The assumptions that are made about the environment where a system will be used may be incorrect Usage of a system in an office environment is likely to be quite different from usage of the same system in a university environment The consequences of system failures affect the perception of reliability Unreliable windscreen wipers in a car may be irrelevant in a dry climate Failures that have serious consequences (such as an engine breakdown in a car) are given greater weight by users than failures that are inconvenient Chapter 2 Reliability Engineering 12" }, { "page_index": 59, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_013.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_013.png", "page_index": 59, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:38+07:00" }, "raw_text": "A system as an input/output mapping Software Engineering Inputs causing erroneous outputs Input set e Program Erroneous outputs Output set Oe Chapter 2 Reliability Engineering 13" }, { "page_index": 60, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_014.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_014.png", "page_index": 60, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:44+07:00" }, "raw_text": "Availability perception Software Engineering Availability is usually expressed as a percentage of the time that the system is available to deliver services e.g. 99.95%. However, this does not take into account two factors: The number of users affected by the service outage. Loss of service in the middle of the night is less important for many systems than loss of service during peak usage periods. The length of the outage. The longer the outage, the more the disruption. Several short outages are less likely to be disruptive than 1 long outage. Long repair times are a particular problem. Chapter 2 Reliability Engineering 14" }, { "page_index": 61, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_015.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_015.png", "page_index": 61, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:48+07:00" }, "raw_text": "Software usage patterns Software Engineering Possible inputs User Erroneous 1 inputs User User 3 2 Chapter 2 Reliability Engineering 15" }, { "page_index": 62, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_016.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_016.png", "page_index": 62, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:56+07:00" }, "raw_text": "Reliability in use Software Engineering Removing X% of the faults in a system will not necessarily improve the reliability by X%. Program defects may be in rarely executed sections of the code so may never be encountered by users. Removing these does not affect the perceived reliability Users adapt their behaviour to avoid system features that may fail for them. A program with known faults may therefore still be perceived as reliable by its users. Chapter 2 Reliability Engineering 16" }, { "page_index": 63, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_017.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_017.png", "page_index": 63, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:57:58+07:00" }, "raw_text": "Software Engineering Reliability requirements Chapter 2 Reliability Engineering 17" }, { "page_index": 64, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_018.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_018.png", "page_index": 64, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:05+07:00" }, "raw_text": "System reliability requirements Software Engineering Functional reliability reguirements define system and software functions that avoid, detect or tolerate faults in the software and so ensure that these faults do not lead to system failure. Software reliability requirements may also be included to cope with hardware failure or operator error. Reliability is a measurable system attribute so non- functional reliability requirements may be specified quantitatively. These define the number of failures that are acceptable during normal use of the system or the time in which the system must be available. Chapter 2 Reliability Engineering 18" }, { "page_index": 65, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_019.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_019.png", "page_index": 65, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:12+07:00" }, "raw_text": "Reliability metrics Software Engineering Reliability metrics are units of measurement of system reliability System reliability is measured by counting the number of operational failures and, where appropriate, relating these to the demands made on the system and the time that the system has been operational. A long-term measurement programme is required to assess the reliability of critical systems. Metrics Probability of failure on demand Rate of occurrence of failures/Mean time to failure Availability Chapter 2 Reliability Engineering 19" }, { "page_index": 66, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_020.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_020.png", "page_index": 66, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:18+07:00" }, "raw_text": "Probability of failure on demand (POFOD) Software Engineering This is the probability that the system will fail when a service reguest is made. Useful when demands for service are intermittent and relatively infrequent. Appropriate for protection systems where services are demanded occasionally and where there are serious consequence if the service is not delivered. Relevant for many safety-critical systems with exception management components Emergency shutdown system in a chemical plant. Chapter 2 Reliability Engineering 20" }, { "page_index": 67, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_021.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_021.png", "page_index": 67, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:24+07:00" }, "raw_text": "Rate of fault occurrence (ROCOF) Software Engineering Reflects the rate of occurrence of failure in the system. ROCOF of 0.002 means 2 failures are likely in each 1000 operational time units e.g. 2 failures per 1000 hours of operation Relevant for systems where the system has to process a large number of similar requests in a short time Credit card processing system, airline booking system. Y Reciprocal of ROCOF is Mean time to Failure (MTTF) Relevant for systems with long transactions i.e. where system processing takes a long time (e.g. CAD systems). MTTF should be longer than expected transaction length Chapter 2 Reliability Engineering 21" }, { "page_index": 68, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_022.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_022.png", "page_index": 68, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:29+07:00" }, "raw_text": "Availability Software Engineering Measure of the fraction of the time that the system is available for use. Takes repair and restart time into account Availability of 0.998 means software is available for 998 out of 1000 time units. Relevant for non-stop, continuously running systems telephone switching systems, railway signalling systems Chapter 2 Reliability Engineering 22" }, { "page_index": 69, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_023.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_023.png", "page_index": 69, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:35+07:00" }, "raw_text": "Availability specification Software Engineering Availability Explanation 0.9 The system is available for 90% of the time. This means that, in a 24-hour period (1,440 minutes), the system will be unavailable for 144 minutes. 0.99 In a 24-hour period, the system is unavailable for 14.4 minutes 0.999 The system is unavailable for 84 seconds in a 24-hour period 0.9999 The system is unavailable for 8.4 seconds in a 24-hour period Roughly, one minute per week. Chapter 2 Reliability Engineering 23" }, { "page_index": 70, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_024.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_024.png", "page_index": 70, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:41+07:00" }, "raw_text": "Non-functional reliability reguirements Software Engineering Non-functional reliability requirements are specifications of the required reliability and availability of a system using one of the reliability metrics (POFOD, ROCOF or AVAIL). Quantitative reliability and availability specification has been used for many years in safety-critical systems but is uncommon for business critical systems. However, as more and more companies demand 24/7 service from their systems, it makes sense for them to be precise about their reliability and availability expectations. Chapter 2 Reliability Engineering 24" }, { "page_index": 71, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_025.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_025.png", "page_index": 71, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:49+07:00" }, "raw_text": "Benefits of reliability specification Software Engineering The process of deciding the required level of the reliability helps to clarify what stakeholders really need It provides a basis for assessing when to stop testing a system. You stop when the system has reached its required reliability level. It is a means of assessing different design strategies intended to improve the reliability of a system. If a regulator has to approve a system (e.g. all systems that are critical to flight safety on an aircraft are regulated), then evidence that a required reliability target has been met is important for system certification. Chapter 2 Reliability Engineering 25" }, { "page_index": 72, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_026.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_026.png", "page_index": 72, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:58:55+07:00" }, "raw_text": "Specifying reliability reguirements Software Engineering Specify the availability and reliability reqguirements for different types of failure. There should be a lower probability of high-cost failures than failures that don't have serious consequences. Specify the availability and reliability reguirements for different types of system service. Critical system services should have the highest reliability but you may be willing to tolerate more failures in less critical services. Think about whether a high level of reliability is really required. Other mechanisms can be used to provide reliable system service Chapter 2 Reliability Engineering 26" }, { "page_index": 73, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_027.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_027.png", "page_index": 73, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:02+07:00" }, "raw_text": "ATM reliability specification Software Engineering Key concerns To ensure that their ATMs carry out customer services as requested and that they properly record customer transactions in the account database To ensure that these ATM systems are available for use when required. Availability, in this case, is more important than reliability Chapter 2 Reliability Engineering 27" }, { "page_index": 74, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_028.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_028.png", "page_index": 74, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:08+07:00" }, "raw_text": "ATM availability specification Software Engineering Y System services The customer account database service; The individual services provided by an ATM such as 'withdraw cash', 'provide account information', etc. The database service is critical as failure of this service means that all of the ATMs in the network are out of action. You should specify this to have a high level of availability. Database availability should be around 0.9999, between 7 am and 11pm. This corresponds to a downtime of less than 1 minute per week Chapter 2 Reliability Engineering 28" }, { "page_index": 75, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_029.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_029.png", "page_index": 75, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:14+07:00" }, "raw_text": "ATM availability specification Software Engineering For an individual ATM, the key reliability issues depends on mechanical reliability and the fact that it can run out of cash. Y A lower level of software availability for the ATM software is acceptable The overall availability of the ATM software might therefore be specified as 0.999, which means that a machine might be unavailable for between 1 and 2 minutes each day Chapter 2 Reliability Engineering 29" }, { "page_index": 76, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_030.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_030.png", "page_index": 76, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:21+07:00" }, "raw_text": "Insulin pump reliability specification Software Engineering Probability of failure (POFOD) is the most appropriate metric Transient failures that can be repaired by user actions such as recalibration of the machine. A relatively low value of POFOD is acceptable (say 0.002) - one failure may occur in every 500 demands. Permanent failures require the software to be re-installed by the manufacturer. This should occur no more than once per year. POFOD for this situation should be less than 0.00002 Chapter 2 Reliability Engineering 30" }, { "page_index": 77, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_031.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_031.png", "page_index": 77, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:27+07:00" }, "raw_text": "Functional reliability reguirements Software Engineering Checking requirements that identify checks to ensure that incorrect data is detected before it leads to a failure Recovery requirements that are geared to help the system recover after a failure has occurred. Redundancy requirements that specify redundant features of the system to be included. Process requirements for reliability which specify the development process to be used may also be included Chapter 2 Reliability Engineering 31" }, { "page_index": 78, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_032.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_032.png", "page_index": 78, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:33+07:00" }, "raw_text": "Examples of functional reliability reguirements Software Engineering RR1: A pre-defined range for all operator inputs shall be defined and the system shall check that all operator inputs fall within this pre-defined range. (Checking) RR2: Copies of the patient database shall be maintained on two separate servers that are not housed in the same building. (Recovery redundancy) RR3: N-version programming shall be used to implement the braking control system. (Redundancy) RR4: The system must be implemented in a safe subset of Ada and checked using static analysis. (Process) Chapter 2 Reliability Engineering 32" }, { "page_index": 79, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_033.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_033.png", "page_index": 79, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:36+07:00" }, "raw_text": "Software Engineering Fault-tolerant architectures Chapter 2 Reliability Engineering 33" }, { "page_index": 80, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_034.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_034.png", "page_index": 80, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:42+07:00" }, "raw_text": "Fault tolerance Software Engineering In critical situations, software systems must be fault tolerant. Fault tolerance is required where there are high availability requirements or where system failure costs are very high. Fault tolerance means that the system can continue in operation in spite of software failure. Even if the system has been proved to conform to its specification, it must also be fault tolerant as there may be specification errors or the validation may be incorrect. Chapter 2 Reliability Engineering 34" }, { "page_index": 81, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_035.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_035.png", "page_index": 81, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:47+07:00" }, "raw_text": "Fault-tolerant system architectures Software Engineering Fault-tolerant systems architectures are used in situations where fault tolerance is essential. These architectures are generally all based on redundancy and diversity Examples of situations where dependable architectures are used: Flight control systems, where system failure could threaten the safety of passengers Reactor systems where failure of a control system could lead to a chemical or nuclear emergency Telecommunication systems, where there is a need for 24/7 availability Chapter 2 Reliability Engineering 35" }, { "page_index": 82, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_036.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_036.png", "page_index": 82, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:53+07:00" }, "raw_text": "Protection systems Software Engineering A specialized system that is associated with some other control system, which can take emergency action if a failure occurs. System to stop a train if it passes a red light System to shut down a reactor if temperature/pressure are too high Protection systems independently monitor the controlled system and the environment. If a problem is detected, it issues commands to take emergency action to shut down the system and avoid a catastrophe Chapter 2 Reliability Engineering 36" }, { "page_index": 83, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_037.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_037.png", "page_index": 83, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T22:59:57+07:00" }, "raw_text": "Protection system architecture Software Engineering System environment Protection Sensors sensors Protection Control system system Actuators Controlled equipment Chapter 2 Reliability Engineering 37" }, { "page_index": 84, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_038.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_038.png", "page_index": 84, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:03+07:00" }, "raw_text": "Protection system functionality Software Engineering Protection systems are redundant because they include monitoring and control capabilities that replicate those in the control software Protection systems should be diverse and use different technology from the control software. They are simpler than the control system so less effort can be expended in validation and dependability assurance Aim is to ensure that there is a low probability of failure on demand for the protection system. Chapter 2 Reliability Engineering 38" }, { "page_index": 85, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_039.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_039.png", "page_index": 85, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:12+07:00" }, "raw_text": "Self-monitoring architectures Software Engineering Multi-channel architectures where the system monitors its own operations and takes action if inconsistencies are detected. The same computation is carried out on each channel and the results are compared. If the results are identical and are produced at the same time, then it is assumed that the system is operating correctly. If the results are different, then a failure is assumed and a failure exception is raised. Chapter 2 Reliability Engineering 39" }, { "page_index": 86, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_040.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_040.png", "page_index": 86, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:16+07:00" }, "raw_text": "Self-monitoring architecture Software Engineering Status Channel 1 Input value Splitter Comparator Output value Channel 2 Chapter 2 Reliability Engineering 40" }, { "page_index": 87, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_041.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_041.png", "page_index": 87, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:22+07:00" }, "raw_text": "Self-monitoring systems Software Engineering Y Hardware in each channel has to be diverse so that common mode hardware failure will not lead to each channel producing the same results. Software in each channel must also be diverse otherwise the same software error would affect each channel. If high-availability is required, you may use several self- checking systems in parallel. This is the approach used in the Airbus family of aircraft for their flight control systems Chapter 2 Reliability Engineering 41" }, { "page_index": 88, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_042.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_042.png", "page_index": 88, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:29+07:00" }, "raw_text": "Airbus flight control system architecture Software Engineering Input value Primary flight control system 1 Channel 1 Status Output Filter Output Splitter Comparator Channel 2 Status Primary flight control system 2 Output Filter Status Primary flight control system 3 Output Filter Secondary flight control system 1 Status Channel 1 Filter Output Splitter Comparator Channel 2 Status Secondary flight control system 2 Output Filter Chapter 2 Reliability Engineering 42" }, { "page_index": 89, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_043.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_043.png", "page_index": 89, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:37+07:00" }, "raw_text": "Airbus architecture discussion Software Engineering The Airbus FCs has 5 separate computers, any one of which can run the control software. Extensive use has been made of diversity Primary systems use a different processor from the secondary systems. Primary and secondary systems use chipsets from different manufacturers. Software in secondary systems is less complex than in primary system - provides only critical functionality. Software in each channel is developed in different programming languages by different teams. Different programming languages used in primary and secondary systems. Chapter 2 Reliability Engineering 43" }, { "page_index": 90, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_044.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_044.png", "page_index": 90, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:41+07:00" }, "raw_text": "N-version programming Software Engineering Multiple versions of a software system carry out computations at the same time. There should be an odd number of computers involved, typically 3. The results are compared using a voting system and the majority result is taken to be the correct result. Approach derived from the notion of triple-modular redundancy, as used in hardware systems. Chapter 2 Reliability Engineering 44" }, { "page_index": 91, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_045.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_045.png", "page_index": 91, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:47+07:00" }, "raw_text": "Hardware fault tolerance Software Engineering Depends on triple-modular redundancy (TMR There are three replicated identical components that receive the same input and whose outputs are compared If one output is different, it is ignored and component failure is assumed. Based on most faults resulting from component failures rather than design faults and a low probability of simultaneous component failure Chapter 2 Reliability Engineering 45" }, { "page_index": 92, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_046.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_046.png", "page_index": 92, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:51+07:00" }, "raw_text": "Triple modular redundancy Software Engineering A1 Input Output A2 selector A3 Chapter 2 Reliability Engineering 46" }, { "page_index": 93, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_047.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_047.png", "page_index": 93, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:00:55+07:00" }, "raw_text": "N-version programming Software Engineering Version 1 Input Output Version 2 selector Agreed result Version 3 Fault manager N software versions Chapter 2 Reliability Engineering 47" }, { "page_index": 94, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_048.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_048.png", "page_index": 94, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:00+07:00" }, "raw_text": "N-version programming Software Engineering The different system versions are designed and implemented by different teams. It is assumed that there is a low probability that they will make the same mistakes. The algorithms used should but may not be different There is some empirical evidence that teams commonly misinterpret specifications in the same way and chose the same algorithms in their systems. Chapter 2 Reliability Engineering 48" }, { "page_index": 95, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_049.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_049.png", "page_index": 95, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:05+07:00" }, "raw_text": "Software diversity Software Engineering Approaches to software fault tolerance depend on software diversity where it is assumed that different implementations of the same software specification will fail in different ways. It is assumed that implementations are (a) independent and (b) do not include common errors. Strategies to achieve diversity Different programming languages Different design methods and tools Explicit specification of different algorithms Chapter 2 Reliability Engineering 49" }, { "page_index": 96, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_050.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_050.png", "page_index": 96, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:10+07:00" }, "raw_text": "Problems with design diversity Software Engineering Teams are not culturally diverse so they tend to tackle Y Characteristic errors Different teams make the same mistakes. Some parts of an implementation are more difficult than others so all teams tend to make mistakes in the same place Specification errors; If there is an error in the specification then this is reflected in all implementations; This can be addressed to some extent by using multiple specification representations. Chapter 2 Reliability Engineering 50" }, { "page_index": 97, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_051.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_051.png", "page_index": 97, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:17+07:00" }, "raw_text": "Specification dependency Software Engineering Both approaches to software redundancy are susceptible to specification errors. If the specification is incorrect, the system could fail This is also a problem with hardware but software specifications are usually more complex than hardware specifications and harder to validate. This has been addressed in some cases by developing separate software specifications from the same user specification. Chapter 2 Reliability Engineering 51" }, { "page_index": 98, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_052.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_052.png", "page_index": 98, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:24+07:00" }, "raw_text": "Improvements in practice Software Engineering In principle, if diversity and independence can be achieved, multi-version programming leads to very significant improvements in reliability and availability In practice, observed improvements are much less significant but the approach seems leads to reliability improvements of between 5 and 9 times. The key question is whether or not such improvements are worth the considerable extra development costs for multi-version programming Chapter 2 Reliability Engineering 52" }, { "page_index": 99, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_053.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_053.png", "page_index": 99, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:26+07:00" }, "raw_text": "Software Engineering Programming for reliability Chapter 2 Reliability Engineering 53" }, { "page_index": 100, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_054.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_054.png", "page_index": 100, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:32+07:00" }, "raw_text": "Dependable programming Software Engineering Good programming practices can be adopted that help reduce the incidence of program faults. . These programming practices support Fault avoidance Fault detection Fault tolerance Chapter 2 Reliability Engineering 54" }, { "page_index": 101, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_055.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_055.png", "page_index": 101, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:40+07:00" }, "raw_text": "Good practice guidelines for dependable programming Software Engineering Dependable programming guidelines 1. Limit the visibility of information in a program 2. Check all inputs for validity 3. Provide a handler for all exceptions 4. Minimize the use of error-prone constructs 5. Provide restart capabilities 6. Check array bounds 7. Include timeouts when calling external components 8. Name all constants that represent real-world values Chapter 2 Reliability Engineering 55" }, { "page_index": 102, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_056.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_056.png", "page_index": 102, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:45+07:00" }, "raw_text": "(1) Limit the visibility of information in a program Software Engineering Program components should only be allowed access to data that they need for their implementation Y This means that accidental corruption of parts of the program state by these components is impossible. You can control visibility by using abstract data types where the data representation is private and you only allow access to the data through predefined operations such as get O and put O Chapter 2 Reliability Engineering 56" }, { "page_index": 103, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_057.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_057.png", "page_index": 103, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:50+07:00" }, "raw_text": "(2) Check all inputs for validity Software Engineering All program take inputs from their environment and make assumptions about these inputs However, program specifications rarely define what to do if an input is not consistent with these assumptions. Consequently, many programs behave unpredictably when presented with unusual inputs and, sometimes these are threats to the security of the system. Consequently, you should always check inputs before processing against the assumptions made about these inputs Chapter 2 Reliability Engineering 57" }, { "page_index": 104, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_058.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_058.png", "page_index": 104, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:01:56+07:00" }, "raw_text": "Validity checks Software Engineering Range checks Check that the input falls within a known range Y Size checks Check that the input does not exceed some maximum size e.g. 40 characters for a name. Y Representation checks Check that the input does not include characters that should not be part of its representation e.g. names do not include numerals. Y Reasonableness checks Use information about the input to check if it is reasonable rather than an extreme value. Chapter 2 Reliability Engineering 58" }, { "page_index": 105, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_059.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_059.png", "page_index": 105, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:02+07:00" }, "raw_text": "(3) Provide a handler for all exceptions Software Engineering A program exception is an error or some unexpected event such as a power failure. Exception handling constructs allow for such events to be handled without the need for continual status checking to detect exceptions Using normal control constructs to detect exceptions needs many additional statements to be added to the program. This adds a significant overhead and is potentially error-prone Chapter 2 Reliability Engineering 59" }, { "page_index": 106, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_060.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_060.png", "page_index": 106, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:06+07:00" }, "raw_text": "Exception handling Software Engineering Code section Normal flow of control Exception detected Normal exit Exception processing Exception handling code Chapter 2 Reliability Engineering 60" }, { "page_index": 107, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_061.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_061.png", "page_index": 107, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:11+07:00" }, "raw_text": "Exception handling Software Engineering Three possible exception handling strategies Signal to a calling component that an exception has occurred and provide information about the type of exception. Carry out some alternative processing to the processing where the exception occurred. This is only possible where the exception handler has enough information to recover from the problem that has arisen. Pass control to a run-time support system to handle the exception. Exception handling is a mechanism to provide some fault tolerance Chapter 2 Reliability Engineering 61" }, { "page_index": 108, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_062.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_062.png", "page_index": 108, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:15+07:00" }, "raw_text": "Software Engineering Program faults are usually a consequence of human error because programmers lose track of the relationships between the different parts of the system This is exacerbated by error-prone constructs in programming languages that are inherently complex or that don't check for mistakes when they could do so. Therefore, when programming, you should try to avoid or at least minimize the use of these error-prone constructs. Chapter 2 Reliability Engineering 62" }, { "page_index": 109, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_063.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_063.png", "page_index": 109, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:21+07:00" }, "raw_text": "Error-prone constructs Software Engineering Unconditional branch (goto) statements Floating-point numbers Inherently imprecise. The imprecision may lead to invalid comparisons. Pointers Pointers referring to the wrong memory areas can corrupt data. Aliasing can make programs difficult to understand and change. Dynamic memory allocation Run-time allocation can cause memory overflow. Chapter 2 Reliability Engineering 63" }, { "page_index": 110, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_064.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_064.png", "page_index": 110, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:26+07:00" }, "raw_text": "Error-prone constructs Software Engineering Parallelism Can result in subtle timing errors because of unforeseen interaction between parallel processes. Recursion Errors in recursion can cause memory overflow as the program stack fills up. Interrupts Interrupts can cause a critical operation to be terminated and make a program difficult to understand. Inheritance Code is not localised. This can result in unexpected behaviour when changes are made and problems of understanding the code Chapter 2 Reliability Engineering 64" }, { "page_index": 111, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_065.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_065.png", "page_index": 111, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:32+07:00" }, "raw_text": "Error-prone constructs Software Engineering Aliasing Using more than 1 name to refer to the same state variable. Unbounded arrays Buffer overflow failures can occur if no bound checking on arrays. > Default input processing An input action that occurs irrespective of the input. This can cause problems if the default action is to transfer control elsewhere in the program. In incorrect or deliberately malicious input can then trigger a program failure Chapter 2 Reliability Engineering 65" }, { "page_index": 112, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_066.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_066.png", "page_index": 112, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:37+07:00" }, "raw_text": "(5) Provide restart capabilities Software Engineering For systems that involve long transactions or user interactions, you should always provide a restart capability that allows the system to restart after failure without users having to redo everything that they have done. Restart depends on the type of system Keep copies of forms so that users don't have to fill them in again if there is a problem Save state periodically and restart from the saved state Chapter 2 Reliability Engineering 66" }, { "page_index": 113, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_067.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_067.png", "page_index": 113, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:43+07:00" }, "raw_text": "(6) Check array bounds Software Engineering In some programming languages, such as C, it is possible to address a memory location outside of the range allowed for in an array declaration. This leads to the well-known 'bounded buffer' vulnerability where attackers write executable code into memory by deliberately writing beyond the top element in an array If your language does not include bound checking, you should therefore always check that an array access is within the bounds of the array. Chapter 2 Reliability Engineering 67" }, { "page_index": 114, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_068.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_068.png", "page_index": 114, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:49+07:00" }, "raw_text": "(7) Include timeouts when calling external components Software Engineering In a distributed system, failure of a remote computer can be 'silent' so that programs expecting a service from that computer may never receive that service or any indication that there has been a failure. To avoid this, you should always include timeouts on all calls to external components. After a defined time period has elapsed without a response, your system should then assume failure and take whatever actions are reguired to recover from this. Chapter 2 Reliability Engineering 68" }, { "page_index": 115, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_069.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_069.png", "page_index": 115, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:55+07:00" }, "raw_text": "(8) Name all constants that represent real-world values Software Engineering Always give constants that reflect real-world values (such as tax rates) names rather than using their numeric values and always refer to them by name You are less likely to make mistakes and type the wrong value when you are using a name rather than a value. This means that when these 'constants' change (for sure, they are not really constant), then you only have to make the change in one place in your program. Chapter 2 Reliability Engineering 69" }, { "page_index": 116, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_070.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_070.png", "page_index": 116, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:02:59+07:00" }, "raw_text": "Software Engineering Reliability measurement Chapter 2 Reliability Engineering 70" }, { "page_index": 117, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_071.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_071.png", "page_index": 117, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:06+07:00" }, "raw_text": "Reliability measurement Software Engineering To assess the reliability of a system, you have to collect data about its operation. The data required may include: The number of system failures given a number of requests for system services. This is used to measure the POFOD. This applies irrespective of the time over which the demands are made. The time or the number of transactions between system failures plus the total elapsed time or total number of transactions. This is used to measure ROCOF and MTTF The repair or restart time after a system failure that leads to loss of service. This is used in the measurement of availability. Availability does not just depend on the time between failures but also on the time required to get the system back into operation. Chapter 2 Reliability Engineering 71" }, { "page_index": 118, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_072.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_072.png", "page_index": 118, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:12+07:00" }, "raw_text": "Reliability testing Software Engineering Reliability testing (Statistical testing) involves running the program to assess whether or not it has reached the required level of reliability. This cannot normally be included as part of a normal defect testing process because data for defect testing is (usually) atypical of actual usage data. Reliability measurement therefore requires a specially designed data set that replicates the pattern of inputs to be processed by the system Chapter 2 Reliability Engineering 72" }, { "page_index": 119, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_073.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_073.png", "page_index": 119, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:15+07:00" }, "raw_text": "Statistical testing Software Engineering Testing software for reliability rather than fault detection. Measuring the number of errors allows the reliability of the software to be predicted. Note that, for statistical reasons, more errors than are allowed for in the reliability specification must be induced. An acceptable level of reliability should be specified and the software tested and amended until that level of reliability is reached. Chapter 2 Reliability Engineering 73" }, { "page_index": 120, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_074.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_074.png", "page_index": 120, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:20+07:00" }, "raw_text": "Reliability measurement Software Engineering Identify Compute Prepare test Apply tests to operational observed data set system profiles reliability Chapter 2 Reliability Engineering 74" }, { "page_index": 121, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_075.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_075.png", "page_index": 121, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:27+07:00" }, "raw_text": "Reliability measurement problems Software Engineering Operational profile uncertainty The operational profile may not be an accurate reflection of the real use of the system High costs of test data generation Costs can be very high if the test data for the system cannot be generated automatically. Statistical uncertainty You need a statistically significant number of failures to compute the reliability but highly reliable systems will rarely fail. Recognizing failure It is not always obvious when a failure has occurred as there may be conflicting interpretations of a specification. Chapter 2 Reliability Engineering 75" }, { "page_index": 122, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_076.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_076.png", "page_index": 122, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:32+07:00" }, "raw_text": "Operational profiles Software Engineering An operational profile is a set of test data whose frequency matches the actual frequency of these inputs from 'normal' usage of the system. A close match with actual usage is necessary otherwise the measured reliability will not be reflected in the actual usage of the system. It can be generated from real data collected from an existing system or (more often) depends on assumptions made about the pattern of usage of a system Chapter 2 Reliability Engineering 76" }, { "page_index": 123, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_077.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_077.png", "page_index": 123, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:37+07:00" }, "raw_text": "An operational profile Software Engineering Input classes Chapter 2 Reliability Engineering 77" }, { "page_index": 124, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_078.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_078.png", "page_index": 124, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:43+07:00" }, "raw_text": "Operational profile generation Software Engineering Should be generated automatically whenever possible. Automatic profile generation is difficult for interactive systems. May be straightforward for 'normal' inputs but it is difficult to predict unlikely' inputs and to create test data for them. Pattern of usage of new systems is unknown. Operational profiles are not static but change as users learn about a new system and change the way that they use it. Chapter 2 Reliability Engineering 78" }, { "page_index": 125, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_079.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_079.png", "page_index": 125, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:50+07:00" }, "raw_text": "Key points Software Engineering Software reliability can be achieved by avoiding the introduction of faults, by detecting and removing faults before system deployment and by including fault tolerance facilities that allow the system to remain operational after a fault has caused a system failure. Reliability requirements can be defined quantitatively in the system requirements specification Reliability metrics include probability of failure on demand (POFOD), rate of occurrence of failure (ROCOF) and availability (AVAlL) Chapter 2 Reliability Engineering 79" }, { "page_index": 126, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_080.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_080.png", "page_index": 126, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:03:56+07:00" }, "raw_text": "Key points Software Engineering Functional reliability requirements are requirements for system functionality, such as checking and redundancy requirements, which help the system meet its non- functional reliability requirements. Dependable system architectures are system architectures that are designed for fault tolerance. There are a number of architectural styles that support fault tolerance including protection systems, self- monitoring architectures and N-version programming Chapter 2 Reliability Engineering 80" }, { "page_index": 127, "chapter_num": 2, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_081.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_2/slide_081.png", "page_index": 127, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:01+07:00" }, "raw_text": "Key points Software Engineering Software diversity is difficult to achieve because it is practically impossible to ensure that each version of the software is truly independent. Dependable programming relies on including redundancy in a program as checks on the validity of inputs and the values of program variables. Statistical testing is used to estimate software reliability It relies on testing the system with test data that matches an operational profile, which reflects the distribution of inputs to the software when it is in use. Chapter 2 Reliability Engineering 81" }, { "page_index": 128, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_001.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_001.png", "page_index": 128, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:05+07:00" }, "raw_text": "Software Engineering Chapter 3 - Safety Engineering 1" }, { "page_index": 129, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_002.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_002.png", "page_index": 129, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:07+07:00" }, "raw_text": "Topics covered Software Engineering Safety-critical systems Safety requirements Safety engineering processes Safety cases 2" }, { "page_index": 130, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_003.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_003.png", "page_index": 130, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:12+07:00" }, "raw_text": "Safety Software Engineering Safety is a property of a system that reflects the system's ability to operate, normally or abnormally, without danger of causing human injury or death and without damage to the system's environment. It is important to consider software safety as most devices whose failure is critical now incorporate software-based control systems." }, { "page_index": 131, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_004.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_004.png", "page_index": 131, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:17+07:00" }, "raw_text": "Software in safety-critical systems Software Engineering Software behaviour is directly related to the overall safety of the system. Software is extensively used for checking and monitoring other safety-critical components in a system. For example, all aircraft engine components are monitored by software looking for early indications of component failure. This software is safety-critical because, if it fails other components may fail and cause an accident. 4" }, { "page_index": 132, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_005.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_005.png", "page_index": 132, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:23+07:00" }, "raw_text": "Safety and reliability Software Engineering Safety and reliability are related but distinct In general, reliability and availability are necessary but not sufficient conditions for system safety Reliability is concerned with conformance to a given specification Safety is concerned with ensuring system cannot cause damage irrespective of whether or not it conforms to its specification. System reliability is essential for safety but is not enough Reliable systems can be unsafe S" }, { "page_index": 133, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_006.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_006.png", "page_index": 133, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:26+07:00" }, "raw_text": "Software Engineering Safety-critical systems 6" }, { "page_index": 134, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_007.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_007.png", "page_index": 134, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:31+07:00" }, "raw_text": "Safety critical systems Software Engineering Systems where it is essential that system operation is always safe i.e. the system should never cause damage to people or the system's environment Examples Control and monitoring systems in aircraft Process control systems in chemical manufacture Automobile control systems such as braking and engine management systems 7" }, { "page_index": 135, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_008.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_008.png", "page_index": 135, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:38+07:00" }, "raw_text": "Safety criticality Software Engineering Primary safety-critical systems Embedded software systems whose failure can cause the associated hardware to fail and directly threaten people. Example is the insulin pump control system Secondary safety-critical systems Systems whose failure results in faults in other (socio-technical) systems, which can then have safety consequences. . For example, the Mentcare system is safety-critical as failure may lead to inappropriate treatment being prescribed. Infrastructure control systems are also secondary safety-critica systems 8" }, { "page_index": 136, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_009.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_009.png", "page_index": 136, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:42+07:00" }, "raw_text": "Hazards Software Engineering Situations or events that can lead to an accident Stuck valve in reactor control system Incorrect computation by software in navigation system Failure to detect possible allergy in medication prescribing system Hazards do not inevitably result in accidents - accident prevention actions can be taken." }, { "page_index": 137, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_010.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_010.png", "page_index": 137, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:04:47+07:00" }, "raw_text": "Safety achievement Software Engineering Hazard avoidance The system is designed so that some classes of hazard simply cannot arise Hazard detection and removal The system is designed so that hazards are detected and removed before they result in an accident. Damage limitation The system includes protection features that minimise the damage that may result from an accident. 10" }, { "page_index": 138, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_011.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_011.png", "page_index": 138, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:00+07:00" }, "raw_text": "Safety terminology Software Engineering Term Definition Accident (or mishap) An unplanned event or sequence of events which results in human death or injury damage to property, or to the environment. An overdose of insulin is an example of an accident. Hazard A condition with the potential for causing or contributing to an accident. A failure of the sensor that measures blood glucose is an example of a hazard. Damage A measure of the loss resulting from a mishap. Damage can range from many people being killed as a result of an accident to minor injury or property damage. Damage resulting from an overdose of insulin could be serious injury or the death of the user of the insulin pump. Hazard severity An assessment of the worst possible damage that could result from a particular hazard Hazard severity can range from catastrophic, where many people are killed, to minor, where only minor damage results. When an individual death is a possibility, a reasonable assessment of hazard severity is 'very high'. Hazard probability The probability of the events occurring which create a hazard. Probability values tend to be arbitrary but range from 'probable' (say 1/100 chance of a hazard occurring) to implausible' (no conceivable situations are likely in which the hazard could occur). The probability of a sensor failure in the insulin pump that results in an overdose is probably low. Risk This is a measure of the probability that the system will cause an accident. The risk is assessed by considering the hazard probability, the hazard severity, and the probability that the hazard will lead to an accident. The risk of an insulin overdose is probably medium to low. 11" }, { "page_index": 139, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_012.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_012.png", "page_index": 139, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:06+07:00" }, "raw_text": "Normal accidents Software Engineering Accidents in complex systems rarely have a single cause as these systems are designed to be resilient to a single point of failure Designing systems so that a single point of failure does not cause an accident is a fundamental principle of safe systems design. Almost all accidents are a result of combinations of malfunctions rather than single failures. It is probably the case that anticipating all problem combinations, especially, in software controlled systems is impossible so achieving complete safety is impossible. Accidents are inevitable 12" }, { "page_index": 140, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_013.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_013.png", "page_index": 140, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:09+07:00" }, "raw_text": "Software Engineering Safety requirements 13" }, { "page_index": 141, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_014.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_014.png", "page_index": 141, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:15+07:00" }, "raw_text": "Safety specification Software Engineering The goal of safety requirements engineering is to identify protection requirements that ensure that system failures do not cause injury or death or environmental damage. Safety requirements may be 'shall not' requirements i.e. they define situations and events that should never occur. Functional safety requirements define: Checking and recovery features that should be included in a system Features that provide protection against system failures and external attacks 14" }, { "page_index": 142, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_015.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_015.png", "page_index": 142, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:18+07:00" }, "raw_text": "Hazard-driven analysis Software Engineering Hazard identification Hazard assessment Hazard analysis Safety requirements specification 15" }, { "page_index": 143, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_016.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_016.png", "page_index": 143, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:23+07:00" }, "raw_text": "Hazard identification Software Engineering Identify the hazards that may threaten the system. Hazard identification may be based on different types of hazard: Physical hazards Electrical hazards Biological hazards Service failure hazards Etc. 16" }, { "page_index": 144, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_017.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_017.png", "page_index": 144, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:27+07:00" }, "raw_text": "Example: Insulin pump Software Engineering Insulin overdose (service failure) Insulin underdose (service failure)) Power failure due to exhausted battery (electrical) Electrical interference with other medical equipment (electrical) Poor sensor and actuator contact (physical) Parts of machine break off in body (physical) Infection caused by introduction of machine (biological) Allergic reaction to materials or insulin (biological) 17" }, { "page_index": 145, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_018.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_018.png", "page_index": 145, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:33+07:00" }, "raw_text": "Hazard assessment Software Engineering The process is concerned with understanding the likelihood that a risk will arise and the potential consequences if an accident or incident should occur. Risks may be categorised as: Intolerable. Must never arise or result in an accident As low as reasonably practical(ALARP). Must minimise the possibility of risk given cost and schedule constraints Acceptable. The consequences of the risk are acceptable and no extra costs should be incurred to reduce hazard probability 18" }, { "page_index": 146, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_019.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_019.png", "page_index": 146, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:38+07:00" }, "raw_text": "The risk triangle Software Engineering Unacceptable region Risk cannot be tolerated Risk tolerated only if ALARP risk reduction is impractical region or excessively expensive Acceptable region Negligible risk 19" }, { "page_index": 147, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_020.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_020.png", "page_index": 147, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:42+07:00" }, "raw_text": "Hazard assessment Software Engineering Estimate the risk probability and the risk severity. It is not normally possible to do this precisely so relative values are used such as 'unlikely', 'rare', 'very high', etc The aim must be to exclude risks that are likely to arise or that have high severity. 20" }, { "page_index": 148, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_021.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_021.png", "page_index": 148, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:51+07:00" }, "raw_text": "Risk classification for the insulin pump Software Engineering ldentified hazard Hazard probability Accident severity Estimated risk Acceptability 1.Insulin overdose Medium High High Intolerable computation 2. Insulin underdose Medium Low Low Acceptable computation 3. Failure of Medium Medium Low ALARP hardware monitoring system 4. Power failure High Low Low Acceptable 5. Machine High High High Intolerable incorrectly fitted 6. Machine breaks in Low High Medium ALARP patient 7. Machine causes Medium Medium Medium ALARP infection 8. Electrical Low High Medium ALARP interference 9. Allergic reaction Low Low Low Acceptable 21" }, { "page_index": 149, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_022.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_022.png", "page_index": 149, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:05:55+07:00" }, "raw_text": "Hazard analysis Software Engineering Concerned with discovering the root causes of risks in a particular system. Techniques: Inductive, bottom-up techniques. Start with a proposed system failure and assess the hazards that could arise from that failure Deductive, top-down technigues. Start with a hazard and deduce what the causes of this could be 22" }, { "page_index": 150, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_023.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_023.png", "page_index": 150, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:00+07:00" }, "raw_text": "Fault-tree analysis Software Engineering A deductive top-down technique Put the risk or hazard at the root of the tree and identify the system states that could lead to that hazard Where appropriate, link these with 'and' or 'or conditions. 23" }, { "page_index": 151, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_024.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_024.png", "page_index": 151, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:08+07:00" }, "raw_text": "An example of a software fault tree Software Engineering Incorrect insulin dose administered or Incorrect Correct dose Delivery sugar level delivered at system measured wrong time failure or or Sensor Sugar Timer Insulin Pump failure computation failure computation signals error incorrect incorrect or or Algorithm Arithmetic Algorithm Arithmetic error error error error 24" }, { "page_index": 152, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_025.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_025.png", "page_index": 152, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:11+07:00" }, "raw_text": "An example of a software fault tree Software Engineering Three possible conditions that can lead to delivery of incorrect dose of insulin Incorrect measurement of blood sugar level Failure of delivery system Dose delivered at wrong time By analysis of the fault tree, root causes of these hazards related to software are: Algorithm error Arithmetic error 25" }, { "page_index": 153, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_026.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_026.png", "page_index": 153, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:15+07:00" }, "raw_text": "Risk reduction Software Engineering Risk reduction strategies Hazard avoidance; Hazard detection and removal Damage limitation. 26" }, { "page_index": 154, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_027.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_027.png", "page_index": 154, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:19+07:00" }, "raw_text": "Strategy use Software Engineering Normally, in critical systems, a mix of risk reduction strategies are used. In a chemical plant control system, the system will include sensors to detect and correct excess pressure in the reactor. 27" }, { "page_index": 155, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_028.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_028.png", "page_index": 155, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:22+07:00" }, "raw_text": "Insulin pump - software risks Software Engineering Arithmetic error A computation causes the value of a variable to overflow or underflow; Maybe include an exception handler for each type of arithmetic error. Algorithmic error Compare dose to be delivered with previous dose or safe maximum doses. Reduce dose if too high. 28" }, { "page_index": 156, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_029.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_029.png", "page_index": 156, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:29+07:00" }, "raw_text": "Examples of safety requirements Software Engineering SR1: The system shall not deliver a single dose of insulin that is greater than a specified maximum dose for a system user. SR2: The system shall not deliver a daily cumulative dose of insulin that is greater than a specified maximum daily dose for a system user. SR3: The system shall include a hardware diagnostic facility that shall be executed at least four times per hour. sR4: The system shall include an exception handler for all of the exceptions that are identified in Table 3. sR5: The audible alarm shall be sounded when any hardware or software anomaly is discovered and a diagnostic message, as defined in Table 4, shall be displayed. SR6: In the event of an alarm, insulin delivery shall be suspended until the user has reset the system and cleared the alarm. 29" }, { "page_index": 157, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_030.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_030.png", "page_index": 157, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:31+07:00" }, "raw_text": "Hazard analysis Software Engineering A hazard log may be used to track hazards throughout the process. 30" }, { "page_index": 158, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_031.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_031.png", "page_index": 158, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:43+07:00" }, "raw_text": "A simplified hazard log entry Software Engineering Hazard Log Page 4: Printed 20.02.2012 System: Insulin Pump System File: InsulinPump/Safety/HazardLog Safety Engineer: James Brown Log version: 1/3 Identified Insulin overdose delivered to patient Hazard ldentified Jane Williams by Criticality 1 class Identified High risk Fault tree YES Date 24.01.07 Location Hazard identified Log,Page 5 Fault tree Jane Williams and Bill Smith creators Fault tree YES Date 28.01.07 Checker James checked Brown 31" }, { "page_index": 159, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_032.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_032.png", "page_index": 159, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:47+07:00" }, "raw_text": "Safety reviews Software Engineering Driven by the hazard register. For each identified hazard, the review team should assess the system and judge whether or not the system can cope with that hazard in a safe way. 32" }, { "page_index": 160, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_033.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_033.png", "page_index": 160, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:53+07:00" }, "raw_text": "Formal verification Software Engineering Eormal methods can be used when a mathematical specification of the system is produced. They are the ultimate static verification technique that may be used at different stages in the development process: A formal specification may be developed and mathematically analyzed for consistency. This helps discover specification errors and omissions Formal arguments that a program conforms to its mathematical specification may be developed. This is effective in discovering programming and design errors. 33" }, { "page_index": 161, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_034.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_034.png", "page_index": 161, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:06:57+07:00" }, "raw_text": "Formal methods cannot guarantee safety Software Engineering The specification may not reflect the real requirements of system users. Users rarely understand formal notations so they cannot directly read the formal specification to find errors and omissions. The proof may contain errors. Program proofs are large and complex, so, like large and complex programs, they usually contain errors. 34" }, { "page_index": 162, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_035.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_035.png", "page_index": 162, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:02+07:00" }, "raw_text": "Model checking Software Engineering Involves creating an extended finite state model of a system and, using a specialized system (a model checker), checking that model for errors. The model checker explores all possible paths through the model and checks that a user-specified property is valid for each path. Model checking is particularly valuable for verifying concurrent systems, which are hard to test. Although model checking is computationally very expensive, it is now practical to use it in the verification of small to medium sized critical systems 35" }, { "page_index": 163, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_036.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_036.png", "page_index": 163, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:06+07:00" }, "raw_text": "Model checking Software Engineering Extended finite- Model state model of building system Requirements, Model design or checker program Property Desired system specification properties Confirmation or counter- examples 36" }, { "page_index": 164, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_037.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_037.png", "page_index": 164, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:10+07:00" }, "raw_text": "Static program analysis Software Engineering Static analysers are software tools for source text processing They parse the program text and try to discover potentially erroneous conditions. They are very effective as an aid to inspections - they are a supplement to but not a replacement for inspections. 37" }, { "page_index": 165, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_038.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_038.png", "page_index": 165, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:16+07:00" }, "raw_text": "Automated static analysis checks Software Engineering Fault class Static analysis check Data faults Variables used before initialization Variables declared but never used Variables assigned twice but never used between assignments Possible array bound violations Undeclared variables Control faults Unreachable code Unconditional branches into loops Input/output faults Variables output twice with no intervening assignment Interface faults Parameter-type mismatches Parameter number mismatches Non-usage of the results of functions Uncalled functions and procedures Storage management faults Unassigned pointers Pointer arithmetic Memory leaks 38" }, { "page_index": 166, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_039.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_039.png", "page_index": 166, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:20+07:00" }, "raw_text": "Use of static analysis Software Engineering Particularly valuable for security checking - the static analyzer can discover areas of vulnerability such as buffer overflows or unchecked inputs. Static analysis is now routinely used in the development of many safety and security critical systems. 39" }, { "page_index": 167, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_040.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_040.png", "page_index": 167, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:23+07:00" }, "raw_text": "Software Engineering Safety cases 40" }, { "page_index": 168, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_041.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_041.png", "page_index": 168, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:28+07:00" }, "raw_text": "Safety and dependability cases Software Engineering Safety and dependability cases are structured documents that set out detailed arguments and evidence that a required level of safety or dependability has been achieved They are normally required by regulators before a system can be certified for operational use. The regulator's responsibility is to check that a system is as safe or dependable as is practical. Regulators and developers work together and negotiate what needs to be included in a system safety/dependability case 41" }, { "page_index": 169, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_042.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_042.png", "page_index": 169, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:33+07:00" }, "raw_text": "The system safety case Software Engineering A safety case is: A documented body of evidence that provides a convincing and valid argument that a system is adequately safe for a given application in a given environment. Arguments in a safety case can be based on formal proof, design rationale, safety proofs, etc. Process factors may also be included. A software safety case is usually part of a wider system safety case that takes hardware and operational issues into account 42" }, { "page_index": 170, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_043.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_043.png", "page_index": 170, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:42+07:00" }, "raw_text": "The contents of a software safety case Software Engineering Chapter Description System description An overview of the system and a description of its critical components Safety The safety requirements abstracted from the system requirements reguirements specification. Details of other relevant system requirements s may also be included Hazard and risk Documents describing the hazards and risks that have been analysis identified and the measures taken to reduce risk. Hazard analyses and hazard logs. Design analysis A set of structured arguments that justify why the design is safe Verification and A description of the procedures used and, where appropriate, the validation test plans for the system. Summaries of the test results showing defects that have been detected and corrected. If formal methods have been used, a formal system specification and any analyses of that specification. Records of static analyses of the source code 43" }, { "page_index": 171, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_044.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_044.png", "page_index": 171, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:47+07:00" }, "raw_text": "Software Engineering Chapter Description Review reports Records of all design and safety reviews Team Evidence of the competence of all of the team involved in safety- competences related systems development and validation. Process QA Records of the quality assurance processes (see Chapter 24, referenced book) carried out during system development. Change Records of all changes proposed, actions taken and, where management appropriate, justification of the safety of these changes. Information about configuration management procedures and configuration processes management logs. Associated safety References to other safety cases that may impact the safety case cases" }, { "page_index": 172, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_045.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_045.png", "page_index": 172, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:52+07:00" }, "raw_text": "Structured arguments Software Engineering Safety cases should be based around structured arguments that present evidence to justify the assertions made in these arguments. The argument justifies why a claim about system safety and security is justified by the available evidence. 45" }, { "page_index": 173, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_046.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_046.png", "page_index": 173, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:07:57+07:00" }, "raw_text": "Structured arguments Software Engineering EVIDENCE Supports EVIDENCE CLAIM << ARGUMENT >> Supports Justifies Supports EVIDENCE 46" }, { "page_index": 174, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_047.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_047.png", "page_index": 174, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:04+07:00" }, "raw_text": "Insulin pump safety argument Software Engineering Arguments are based on claims and evidence. Insulin pump safety: Claim: The maximum single dose of insulin to be delivered (CurrentDose) will not exceed MaxDose Evidence: Safety argument for insulin pump (discussed later) Evidence: Test data for insulin pump. The value of currentDose was correctly computed in 400 tests Evidence: Static analysis report for insulin pump software revealed no anomalies that affected the value of CurrentDose Argument: The evidence presented demonstrates that the maximum dose of insulin that can be computed = MaxDose 47" }, { "page_index": 175, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_048.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_048.png", "page_index": 175, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:08+07:00" }, "raw_text": "Structured safety arguments Software Engineering Structured arguments that demonstrate that a system meets its safety obligations It is not necessary to demonstrate that the program works as intended; the aim is simply to demonstrate safety. Generally based on a claim hierarchy. You start at the leaves of the hierarchy and demonstrate safety This implies the higher-level claims are true. 48" }, { "page_index": 176, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_049.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_049.png", "page_index": 176, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:13+07:00" }, "raw_text": "A safety claim hierarchy for the insulin pump Software Engineering The insulin pump will not deliver a single dose of insulin that is unsafe The maximum single maxDose is set up maxDose is a safe dose computed by correctly when the dose for the user of the pump software pump is configured the insulin pump will not exceed maxDose In normal If the software fails operation, the the maximum dose maximum dose computed will not computed will not exceed maxDose exceed maxDose 49" }, { "page_index": 177, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_050.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_050.png", "page_index": 177, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:18+07:00" }, "raw_text": "Software safety arguments Software Engineering Safety arguments are intended to show that the system cannot reach in unsafe state. These are weaker than correctness arguments which must show that the system code conforms to its specification. They are generally based on proof by contradiction Assume that an unsafe state can be reached; Show that this is contradicted by the program code. A graphical model of the safety argument may be developed. 50" }, { "page_index": 178, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_051.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_051.png", "page_index": 178, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:23+07:00" }, "raw_text": "Construction of a safety argument Software Engineering Establish the safe exit conditions for a component or a program. Starting from the END of the code, work backwards until you have identified all paths that lead to the exit of the code. Assume that the exit condition is false. Show that, for each path leading to the exit that the assignments made in that path contradict the assumption of an unsafe exit from the component 51" }, { "page_index": 179, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_052.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_052.png", "page_index": 179, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:29+07:00" }, "raw_text": "Insulin dose computation with safety checks Software Engineering -- The insulin dose to be delivered is a function of blood sugar level, - the previous dose delivered and the time of delivery of the previous dose currentDose = computelnsulin ; // Safety checkadjust currentDose if necessary // if statement 1 if (previousDose == 0) if (currentDose > maxDose/2) currentDose = maxDose/2 : else if (currentDose > (previousDose * 2) ) currentDose = previousDose * 2 : // if statement 2 if ( currentDose < minimumDose ) currentDose = 0 : else if ( currentDose > maxDose ) currentDose = maxDose : administerInsulin (currentDose) ; 52" }, { "page_index": 180, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_053.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_053.png", "page_index": 180, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:36+07:00" }, "raw_text": "Informal safety argument based on demonstrating contradictions Software Engineering Overdose administered administerlnsulin currentDose > Pre-condition maxDose for unsafe state or Contradiction currentDose >= minimumDose and currentDose=maxDose Contradiction Contradiction currentDose = currentDose = 0 maxDose assigr assign if statement 2 currentDose= currentDose = 0 not executed maxDose if statement 2 if statement 2 then branch else branch executed executed 53" }, { "page_index": 181, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_054.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_054.png", "page_index": 181, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:40+07:00" }, "raw_text": "Program paths Software Engineering Neither branch of if-statement 2 is executed Can only happen if CurrentDose is >= minimumDose and <= maxDose Y then branch of if-statement 2 is executed currentDose = 0 else branch of if-statement 2 is executed currentDose = maxDose In all cases, the post conditions contradict the unsafe condition that the dose administered is greater than maxDose 54" }, { "page_index": 182, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_055.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_055.png", "page_index": 182, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:45+07:00" }, "raw_text": "Key points Software Engineering Safety-critical systems are systems whose failure can lead to human injury or death. A hazard-driven approach is used to understand the safety requirements for safety-critical systems. You identify potential hazards and decompose these (using methods such as fault tree analysis) to discover their root causes. You then specify requirements to avoid or recover from these problems It is important to have a well-defined, certified process for safety-critical systems development. This should include the identification and monitoring of potential hazards. 55" }, { "page_index": 183, "chapter_num": 3, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_056.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_3/slide_056.png", "page_index": 183, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:50+07:00" }, "raw_text": "Key points Software Engineering Static analysis is an approach to V & V that examines the source code of a system, looking for errors and anomalies. It allows all parts of a program to be checked. not just those parts that are exercised by system tests. Model checking is a formal approach to static analysis that exhaustively checks all states in a system for potential errors. Safety and dependability cases collect the evidence that demonstrates a system is safe and dependable. Safety cases are required when an external regulator must certify the system before it is used. 56" }, { "page_index": 184, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_001.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_001.png", "page_index": 184, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:54+07:00" }, "raw_text": "Software Engineering Chapter 4 - Security Engineering Chapter 4 Security Engineering 1" }, { "page_index": 185, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_002.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_002.png", "page_index": 185, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:08:59+07:00" }, "raw_text": "Topics covered Software Engineering Security and dependability Security and organizations Security requirements Secure systems design Security testing and assurance Chapter 4 Security Engineering 2" }, { "page_index": 186, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_003.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_003.png", "page_index": 186, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:03+07:00" }, "raw_text": "Security engineering Software Engineering Tools, techniques and methods to support the development and maintenance of systems that can resist malicious attacks that are intended to damage a computer-based system or its data. A sub-field of the broader field of computer security Chapter 4 Security Engineering 3" }, { "page_index": 187, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_004.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_004.png", "page_index": 187, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:09+07:00" }, "raw_text": "Security dimensions Software Engineering Confidentiality Information in a system may be disclosed or made accessible to people or programs that are not authorized to have access to that information. Integrity Information in a system may be damaged or corrupted making it unusual or unreliable Availability Access to a system or its data that is normally available may not be possible. Chapter 4 Security Engineering 4" }, { "page_index": 188, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_005.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_005.png", "page_index": 188, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:15+07:00" }, "raw_text": "Security levels Software Engineering Infrastructure security, which is concerned with maintaining the security of all systems and networks that provide an infrastructure and a set of shared services to the organization. Application security, which is concerned with the security of individual application systems or related groups of systems. Operational security, which is concerned with the secure operation and use of the organization's systems. Chapter 4 Security Engineering 5" }, { "page_index": 189, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_006.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_006.png", "page_index": 189, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:19+07:00" }, "raw_text": "System layers where security may be compromised Software Engineering Application Reusable components and libraries Middleware Database management Generic, shared applications (browsers, e--mail, etc) Operating System Network Computer hardware Chapter 4 Security Engineering 6" }, { "page_index": 190, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_007.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_007.png", "page_index": 190, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:23+07:00" }, "raw_text": "Application/infrastructure security Software Engineering Application security is a software engineering problem where the system is designed to resist attacks. Infrastructure security is a systems management problem where the infrastructure is configured to resist attacks. The focus of this chapter is application security rather than infrastructure security Chapter 4 Security Engineering 7" }, { "page_index": 191, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_008.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_008.png", "page_index": 191, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:28+07:00" }, "raw_text": "System security management Software Engineering User and permission management Adding and removing users from the system and setting up appropriate permissions for users Software deployment and maintenance Installing application software and middleware and configuring these systems so that vulnerabilities are avoided. Attack monitoring, detection and recovery Monitoring the system for unauthorized access, design strategies for resisting attacks and develop backup and recovery strategies Chapter 4 Security Engineering 8" }, { "page_index": 192, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_009.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_009.png", "page_index": 192, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:33+07:00" }, "raw_text": "Operational security Software Engineering Primarily a human and social issue Concerned with ensuring the people do not take actions that may compromise system security E.g. Tell others passwords, leave computers logged on Users sometimes take insecure actions to make it easier for them to do their jobs. There is therefore a trade-off between system security and system effectiveness. Chapter 4 Security Engineering 9" }, { "page_index": 193, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_010.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_010.png", "page_index": 193, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:36+07:00" }, "raw_text": "Software Engineering Security and dependability Chapter 4 Security Engineering 10" }, { "page_index": 194, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_011.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_011.png", "page_index": 194, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:42+07:00" }, "raw_text": "Security Software Engineering The security of a system is a system property that reflects the system's ability to protect itself from accidental or deliberate external attack. Security is essential as most systems are networked so that external access to the system through the Internet is possible. Security is an essential pre-requisite for availability reliability and safety Chapter 4 Security Engineering 11" }, { "page_index": 195, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_012.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_012.png", "page_index": 195, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:47+07:00" }, "raw_text": "Fundamental security Software Engineering If a system is a networked system and is insecure then statements about its reliability and its safety are unreliable. Therefore, the reliability and safety assurance is no longer valid. Chapter 4 Security Engineering 12" }, { "page_index": 196, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_013.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_013.png", "page_index": 196, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:09:55+07:00" }, "raw_text": "Security terminology Software Engineering Term Definition Asset Something of value which has to be protected. The asset may be the software system itself or data used by that system. Attack An exploitation of a system's vulnerability. Generally, this is from outside the system and is a deliberate attempt to cause some damage. Control A protective measure that reduces a system's vulnerability. Encryption is an example of a control that reduces a vulnerability of a weak access control system Exposure Possible loss or harm to a computing system. This can be loss or damage to data, or can be a loss of time and effort if recovery is necessary after a security breach. Threat Circumstances that have potential to cause loss or harm. You can think of these as a system vulnerability that is subjected to an attack. Vulnerability A weakness in a computer-based system that may be exploited to cause loss or harm. Chapter 4 Security Engineering 13" }, { "page_index": 197, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_014.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_014.png", "page_index": 197, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:06+07:00" }, "raw_text": "Examples of security terminology (Mentcare) Software Engineering Term Example Asset The records of each patient that is receiving or has received treatment. Exposure Potential financial loss from future patients who do not seek treatment because they do not trust the clinic to maintain their data. Financial loss from legal action by the sports star. Loss of reputation. Vulnerability A weak password system which makes it easy for users to set guessable passwords. User ids that are the same as names. Attack An impersonation of an authorized user Threat An unauthorized user will gain access to the system by guessing the credentials (login name and password) of an authorized user. Control A password checking system that disallows user passwords that are proper names or words that are normally included in a dictionary. Chapter 4 Security Engineering 14" }, { "page_index": 198, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_015.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_015.png", "page_index": 198, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:12+07:00" }, "raw_text": "Threat types Software Engineering Interception threats that allow an attacker to gain access to an asset. A possible threat to the Mentcare system might be a situation where an attacker gains access to the records of an individual patient. Interruption threats that allow an attacker to make part of the system unavailable. A possible threat might be a denial of service attack on a system database server so that database connections become impossible. Chapter 4 Security Engineering 15" }, { "page_index": 199, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_016.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_016.png", "page_index": 199, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:18+07:00" }, "raw_text": "Threat types Software Engineering Modification threats that allow an attacker to tamper with a system asset. In the Mentcare system, a modification threat would be where an attacker alters or destroys a patient record. Fabrication threats that allow an attacker to insert false information into a system. This is perhaps not a credible threat in the Mentcare system but would be a threat in a banking system, where false transactions might be added to the system that transfer money to the perpetrator's bank account. Chapter 4 Security Engineering 16" }, { "page_index": 200, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_017.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_017.png", "page_index": 200, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:25+07:00" }, "raw_text": "Security assurance Software Engineering Vulnerability avoidance The system is designed so that vulnerabilities do not occur. For example, if there is no external network connection then external attack is impossible Attack detection and elimination The system is designed so that attacks on vulnerabilities are detected and neutralised before they result in an exposure. For example, virus checkers find and remove viruses before they infect a system Exposure limitation and recovery The system is designed so that the adverse consequences of a successful attack are minimised. For example, a backup policy allows damaged information to be restored Chapter 4 Security Engineering 17" }, { "page_index": 201, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_018.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_018.png", "page_index": 201, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:32+07:00" }, "raw_text": "Security and dependability Software Engineering Security and reliability If a system is attacked and the system or its data are corrupted as a consequence of that attack, then this may induce system failures that compromise the reliability of the system. Security and availability A common attack on a web-based system is a denial of service attack, where a web server is flooded with service reguests from a range of different sources. The aim of this attack is to make the system unavailable Chapter 4 Security Engineering 18" }, { "page_index": 202, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_019.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_019.png", "page_index": 202, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:39+07:00" }, "raw_text": "Security and dependability Software Engineering Security and safety An attack that corrupts the system or its data means that assumptions about safety may not hold. Safety checks rely on analysing the source code of safety critical software and assume the executing code is a completely accurate translation of that source code. If this is not the case, safety-related failures may be induced and the safety case made for the software is invalid. Security and resilience Resilience is a system characteristic that reflects its ability to resist and recover from damaging events. The most probable damaging event on networked software systems is a cyberattack of some kind so most of the work now done in resilience is aimed at deterring, detecting and recovering from such attacks. Chapter 4 Security Engineering 19" }, { "page_index": 203, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_020.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_020.png", "page_index": 203, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:45+07:00" }, "raw_text": "Software Engineering Security and organizations Chapter 4 Security Engineering 20" }, { "page_index": 204, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_021.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_021.png", "page_index": 204, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:51+07:00" }, "raw_text": "Security is a business issue Software Engineering Security is expensive and it is important that security decisions are made in a cost-effective way There is no point in spending more than the value of an asset to keep that asset secure. Organizations use a risk-based approach to support security decision making and should have a defined security policy based on security risk analysis Security risk analysis is a business rather than a technical process Chapter 4 Security Engineering 21" }, { "page_index": 205, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_022.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_022.png", "page_index": 205, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:10:58+07:00" }, "raw_text": "Organizational security policies Software Engineering Security policies should set out general information access strategies that should apply across the organization. The point of security policies is to inform everyone in an organization about security so these should not be long and detailed technical documents From a security engineering perspective, the security policy defines, in broad terms, the security goals of the organization. The security engineering process is concerned with implementing these goals. Chapter 4 Security Engineering 22" }, { "page_index": 206, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_023.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_023.png", "page_index": 206, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:06+07:00" }, "raw_text": "Security policies Software Engineering The assets that must be protected It is not cost-effective to apply stringent security procedures to all organizational assets. Many assets are not confidential and can be made freely available. 4 The level of protection that is required for different types of asset For sensitive personal information, a high level of security is required; for other information, the consequences of loss may be minor so a lower level of security is adequate Chapter 4 Security Engineering 23" }, { "page_index": 207, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_024.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_024.png", "page_index": 207, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:12+07:00" }, "raw_text": "Security policies Software Engineering The responsibilities of individual users, managers and the organization The security policy should set out what is expected of users e.g. strong passwords, log out of computers, office security, etc. Existing security procedures and technologies that should be maintained For reasons of practicality and cost, it may be essential to continue to use existing approaches to security even where these have known limitations Chapter 4 Security Engineering 24" }, { "page_index": 208, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_025.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_025.png", "page_index": 208, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:16+07:00" }, "raw_text": "Software Engineering Security requirements Chapter 4 Security Engineering 25" }, { "page_index": 209, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_026.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_026.png", "page_index": 209, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:23+07:00" }, "raw_text": "Security specification Software Engineering Security specification has something in common with safety requirements specification - in both cases, your concern is to avoid something bad happening. Four major differences Safety problems are accidental - the software is not operating in a hostile environment. In security, you must assume that attackers have knowledge of system weaknesses When safety failures occur, you can look for the root cause or weakness that led to the failure. When failure results from a deliberate attack, the attacker may conceal the cause of the failure. Shutting down a system can avoid a safety-related failure. Causing a shut down may be the aim of an attack. Safety-related events are not generated from an intelligent adversary An attacker can probe defenses over time to discover weaknesses. Chapter 4 Security Engineering 26" }, { "page_index": 210, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_027.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_027.png", "page_index": 210, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:28+07:00" }, "raw_text": "Types of security requirement Software Engineering ldentification reguirements. Authentication requirements Authorisation requirements Immunity requirements. Integrity requirements. Intrusion detection requirements. Non-repudiation requirements. Privacy requirements. Security auditing requirements. System maintenance security requirements Chapter 4 Security Engineering 27" }, { "page_index": 211, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_028.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_028.png", "page_index": 211, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:34+07:00" }, "raw_text": "Security reguirement classification Software Engineering Risk avoidance requirements set out the risks that should be avoided by designing the system so that these risks simply cannot arise. Risk detection reguirements define mechanisms that identify the risk if it arises and neutralise the risk before losses occur. Risk mitigation requirements set out how the system should be designed so that it can recover from and restore system assets after some loss has occurred Chapter 4 Security Engineering 28" }, { "page_index": 212, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_029.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_029.png", "page_index": 212, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:38+07:00" }, "raw_text": "The preliminary risk assessment process for security requirements Software Engineering Asset identification Asset value Exposure assessment assessment Threat Attack identification assessment Feasibility Security req Control definition identification assessment Chapter 4 Security Engineering 29" }, { "page_index": 213, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_030.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_030.png", "page_index": 213, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:43+07:00" }, "raw_text": "Security risk assessment Software Engineering Asset identification Identify the key system assets (or services) that have to be protected. Y Asset value assessment Estimate the value of the identified assets Exposure assessment Assess the potential losses associated with each asset. Threat identification Identify the most probable threats to the system assets Chapter 4 Security Engineering 30" }, { "page_index": 214, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_031.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_031.png", "page_index": 214, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:50+07:00" }, "raw_text": "Security risk assessment Software Engineering Y Attack assessment Decompose threats into possible attacks on the system and the ways that these may occur. Control identification Propose the controls that may be put in place to protect an asset. Feasibility assessment Assess the technical feasibility and cost of the controls. Security requirements definition Define system security requirements. These can be infrastructure or application system requirements. Chapter 4 Security Engineering 31" }, { "page_index": 215, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_032.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_032.png", "page_index": 215, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:11:58+07:00" }, "raw_text": "Asset analysis in a preliminary risk assessment report for the Mentcare system Software Engineering Asset Value Exposure The information system High. Required to support all High. Financial loss as clinics clinical consultations. Potentially may have to be canceled. Costs safety-critical. of restoring system. Possible patient harm if treatment cannot be prescribed. The patient database High. Required to support all High. Financial loss as clinics clinical consultations. Potentially may have to be canceled. Costs safety-critical. of restoring system. Possible patient harm if treatment cannot be prescribed. An individual patient record Normally low although may be Low direct losses but possible high for specific high-profile loss of reputation patients. Chapter 4 Security Engineering 32" }, { "page_index": 216, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_033.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_033.png", "page_index": 216, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:12+07:00" }, "raw_text": "Threat and control analysis in a preliminary risk assessment report Software Engineering Threat Probability Control Feasibility An unauthorized user Low Only allow system Low cost of implementation but care must be taken with key gains access as management from system manager and specific locations that are distribution and to ensure that makes system physically secure. keys are available in the event unavailable of an emergency An unauthorized user High Require all users to Technically feasible but high- gains access as authenticate themselves cost solution. Possible user system and using user a biometric resistance accesses confidential mechanism. Simple and transparent to information Log g all changes to implement and l also supports patient information to recovery. track system usage. Chapter 4 Security Engineering 33" }, { "page_index": 217, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_034.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_034.png", "page_index": 217, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:20+07:00" }, "raw_text": "Security requirements for the Mentcare system Software Engineering Y Patient information shall be downloaded at the start of a clinic session to a secure area on the system client that is used by clinical staff. All patient information on the system client shall be encrypted. Patient information shall be uploaded to the database after a clinic session has finished and deleted from the client computer. A log on a separate computer from the database server must be maintained of all changes made to the system database. Chapter 4 Security Engineering 34" }, { "page_index": 218, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_035.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_035.png", "page_index": 218, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:27+07:00" }, "raw_text": "Misuse cases Software Engineering Misuse cases are instances of threats to a system Interception threats Attacker gains access to an asset Interruption threats Attacker makes part of a system unavailable Modification threats A system asset is tampered Y Fabrication threats False information is added to a system Chapter 4 Security Engineering 35" }, { "page_index": 219, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_036.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_036.png", "page_index": 219, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:34+07:00" }, "raw_text": "Misuse cases Software Engineering Register patient Unregister patient Impersonate receptionist View patient info. Medical Intercept Attacker receptionist transfer Transfer data Contact patient Chapter 4 Security Engineering 36" }, { "page_index": 220, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_037.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_037.png", "page_index": 220, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:40+07:00" }, "raw_text": "Mentcare use case - Transfer data Software Engineering Mentcare system: Transfer data Actors Medical receptionist, Patient records system (PRS) Description A receptionist may transfer data from the Mentcare system to a general patient record database that is maintained l by a health authority. The information transferred may either be updated personal information (address, phone number, etc.) or a summary of the patient's diagnosis and treatment. Data Patient's personal information, treatment summary. Stimulus User command issued by medical receptionist. Response Confirmation that PRS has been updated Comments The receptionist must have appropriate security permissions to access the patient information and the PRS Chapter 4 Security Engineering 3/" }, { "page_index": 221, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_038.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_038.png", "page_index": 221, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:47+07:00" }, "raw_text": "Mentcare misuse case: Intercept transfer Software Engineering Mentcare system: Intercept transfer (Misuse case) Actors Medical receptionist, Patient records system (PRS), Attacker Description A receptionist transfers data from his or her PC to the Mentcare system on the server. An attacker intercepts the data transfer and takes a copy of that data. Data (assets) Patient's personal information, treatment summary Attacks A network monitor is added to the system and packets from the receptionist to the server are intercepted. A spoof server is set up between the receptionist and the database server so that receptionist believes they are interacting with the real system. Chapter 4 Security Engineering 38" }, { "page_index": 222, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_039.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_039.png", "page_index": 222, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:53+07:00" }, "raw_text": "Misuse case: Intercept transfer Software Engineering Mentcare system: Intercept transfer (Misuse case) Mitigations All networking equipment must be maintained in a locked room. Engineers accessing the equipment must be accredited. All data transfers between the client and server must be encrypted. Certificate-based client-server communication must be used Requirements All communications between the client and the server must use the Secure Socket Layer (ssL). The https protocol uses certificate based authentication and encryption. Chapter 4 Security Engineering 39" }, { "page_index": 223, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_040.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_040.png", "page_index": 223, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:12:58+07:00" }, "raw_text": "Software Engineering Secure systems design Chapter 4 Security Engineering 40" }, { "page_index": 224, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_041.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_041.png", "page_index": 224, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:02+07:00" }, "raw_text": "Secure systems design Software Engineering Security should be designed into a system - it is very difficult to make an insecure system secure after it has been designed or implemented Architectural design how do architectural design decisions affect the security of a system? Y Good practice what is accepted good practice when designing secure systems? Chapter 4 Security Engineering 41" }, { "page_index": 225, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_042.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_042.png", "page_index": 225, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:09+07:00" }, "raw_text": "Design compromises Software Engineering Adding security features to a system to enhance its security affects other attributes of the system Performance Additional security checks slow down a system so its response time or throughput may be affected Usability Security measures may require users to remember information or reguire additional interactions to complete a transaction. This makes the system less usable and can frustrate system users. Chapter 4 Security Engineering 42" }, { "page_index": 226, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_043.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_043.png", "page_index": 226, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:15+07:00" }, "raw_text": "Design and risk assessment Software Engineering Technology choices System System Architectural Design risk design requirements design assessment Design and Design assets requirements changes Chapter 4 Security Engineering 43" }, { "page_index": 227, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_044.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_044.png", "page_index": 227, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:23+07:00" }, "raw_text": "Vulnerabilities associated with technology choices Software Engineering Technology choice Vulnerabilities Users set Authorized users reveal Login/password guessable their passwords to authentication passwords unauthorised users Server subject to Confidential information denial of service may be left in browser Client/server attack cache architecture using web browser Browser security loopholes lead to unauthorized access Fine-grain logging Authorization can't be Use of editable of changes is varied according to user's web forms impossible role Cnapter 4 Security Engineering 44" }, { "page_index": 228, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_045.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_045.png", "page_index": 228, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:28+07:00" }, "raw_text": "Architectural design Software Engineering Two fundamental issues have to be considered when designing an architecture for security. Protection . How should the system be organised so that critical assets can be protected against external attack? Distribution . How should system assets be distributed so that the effects of a successful attack are minimized? These are potentially conflicting If assets are distributed, then they are more expensive to protect. If assets are protected, then usability and performance requirements may be compromised. Chapter 4 Security Engineering 45" }, { "page_index": 229, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_046.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_046.png", "page_index": 229, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:33+07:00" }, "raw_text": "Protection Software Engineering Y Platform-level protection Top-level controls on the platform on which a system runs. Application-level protection Specific protection mechanisms built into the application itself e.g. additional password protection. Record-level protection Protection that is invoked when access to specific information is requested These lead to a layered protection architecture Chapter 4 Security Engineering 46" }, { "page_index": 230, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_047.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_047.png", "page_index": 230, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:38+07:00" }, "raw_text": "A layered protection architecture Software Engineering Platform level protection System System File integrity authentication authorization management Application level protection Database Database Transaction Database login authorization management recovery Record level protection Record access Record Record integrity authorization encryption management Patient records Chapter 4 Security Engineering 47" }, { "page_index": 231, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_048.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_048.png", "page_index": 231, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:42+07:00" }, "raw_text": "Distribution Software Engineering Distributing assets means that attacks on one system do not necessarily lead to complete loss of system service Each platform has separate protection features and may be different from other platforms so that they do not share a common vulnerability Distribution is particularly important if the risk of denial of service attacks is high Chapter 4 Security Engineering 48" }, { "page_index": 232, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_049.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_049.png", "page_index": 232, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:50+07:00" }, "raw_text": "Authentication and authorization Authentication and authorization New York trading system London trading system Software Engineering International International Us user accounts UK user accounts user accounts user accounts US trading UK trading US equity data UK equity data history history International International US funds data UK funds data equity prices equity prices Authentication and authorization Authentication and authorization Frankfurt trading system Hong Kong trading system Distributed European user International International HK user accounts accounts user accounts user accounts assets in an Euro. trading HK trading Euro. equity data Asian equity data equity history history trading International International Euro. funds data Asian funds data equity prices equity prices system Chapter 4 Security Engineering 49" }, { "page_index": 233, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_050.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_050.png", "page_index": 233, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:13:54+07:00" }, "raw_text": "Software Engineering Secure systems programming Chapter 4 Security Engineering 50" }, { "page_index": 234, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_051.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_051.png", "page_index": 234, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:02+07:00" }, "raw_text": "Aspects of secure systems programming Software Engineering Vulnerabilities are often language-specific Array bound checking is automatic in languages like Java so this is not a vulnerability that can be exploited in Java programs. However, millions of programs are written in C and C++ as these allow for the development of more efficient software so simply avoiding the use of these languages is not a realistic option. Security vulnerabilities are closely related to program reliability Programs without array bound checking can crash so actions taken to improve program reliability can also improve system security. Chapter 4 Security Engineering 51" }, { "page_index": 235, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_052.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_052.png", "page_index": 235, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:09+07:00" }, "raw_text": "Dependable programming guidelines Software Engineering Dependable programming guidelines 1. Limit the visibility of information in a program 2. Check all inputs for validity 3. Provide a handler for all exceptions 4. Minimize the use of error-prone constructs 5. Provide restart capabilities 6. Check array bounds 7. Include timeouts when calling external components 8. Name all constants that represent real-world values Chapter 4 Security Engineering 52" }, { "page_index": 236, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_053.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_053.png", "page_index": 236, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:14+07:00" }, "raw_text": "Software Engineering Security testing and assurance Chapter 4 Security Engineering 53" }, { "page_index": 237, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_054.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_054.png", "page_index": 237, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:18+07:00" }, "raw_text": "Security testing Software Engineering Testing the extent to which the system can protect itself from external attacks. Problems with security testing Security requirements are 'shall not' requirements i.e. they specify what should not happen. It is not usually possible to define security reguirements as simple constraints that can be checked by the system. The people attacking a system are intelligent and look for vulnerabilities. They can experiment to discover weaknesses and loopholes in the system. Chapter 4 Security Engineering 54" }, { "page_index": 238, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_055.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_055.png", "page_index": 238, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:24+07:00" }, "raw_text": "Security validation Software Engineering Experience-based testing The system is reviewed and analysed against the types of attack that are known to the validation team. Penetration testing A team is established whose goal is to breach the security of the system by simulating attacks on the system. Tool-based analysis Various security tools such as password checkers are used to analyse the system in operation. Formal verification The system is verified against a formal security specification. Chapter 4 Security Engineering 55" }, { "page_index": 239, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_056.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_056.png", "page_index": 239, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:32+07:00" }, "raw_text": "Examples of entries in a security checklist Software Engineering Security checklist 1. Do all files that are created in the application have appropriate access permissions? The wrong access permissions may lead to these files being accessed by unauthorized users. 2. Does the system automatically terminate user sessions after a period of inactivity? Sessions that are left active may allow unauthorized access through an unattended computer. 3. If the system is written in a programming language without array bound checking, are there situations where buffer overflow may be exploited? Buffer overflow may allow attackers to send code strings to the system and then execute them. 4. If passwords are set, does the system check that passwords are 'strong'? Strong passwords consist of mixed letters, numbers, and punctuation, and are not normal dictionary entries. They are more difficult to break than simple passwords. 5. Are inputs from the system's environment always checked against an input specification? Incorrect processing of badly formed inputs is a common cause of security vulnerabilities. Chapter 4 Security Engineering 56" }, { "page_index": 240, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_057.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_057.png", "page_index": 240, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:38+07:00" }, "raw_text": "Key points Software Engineering Security engineering is concerned with how to develop systems that can resist malicious attacks Security threats can be threats to confidentiality, integrity or availability of a system or its data Security risk management is concerned with assessing possible losses from attacks and deriving security requirements to minimise losses To specify security requirements, you should identify the assets that are to be protected and define how security techniques and technology should be used to protect these assets. Chapter 4 Security Engineering 57" }, { "page_index": 241, "chapter_num": 4, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_058.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_4/slide_058.png", "page_index": 241, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:45+07:00" }, "raw_text": "Key points Software Engineering Key issues when designing a secure systems architecture include organizing the system structure to protect key assets and distributing the system assets to minimize the losses from a successful attack. Security design guidelines sensitize system designers to security issues that they may not have considered. They provide a basis for creating security review checklists. Security validation is difficult because security requirements state what should not happen in a system rather than what should. Furthermore, system attackers are intelligent and may have more time to probe for weaknesses than is available for security testing Chapter 4 Security Engineering 58" }, { "page_index": 242, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_001.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_001.png", "page_index": 242, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:47+07:00" }, "raw_text": "Software Engineering Chapter 5 - Resilience Engineering Chapter 5 Resilience engineering 1" }, { "page_index": 243, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_002.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_002.png", "page_index": 243, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:52+07:00" }, "raw_text": "Topics covered Software Engineering Cybersecurity Sociotechnical resilience Resilient systems design Chapter 5 Resilience engineering 2" }, { "page_index": 244, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_003.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_003.png", "page_index": 244, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:14:57+07:00" }, "raw_text": "Resilience Software Engineering The resilience of a system is a judgment of how well that system can maintain the continuity of its critical services in the presence of disruptive events, such as equipment failure and cyberattacks. Cyberattacks by malicious outsiders are perhaps the most serious threat faced by networked systems but resilience is also intended to cope with system failures and other disruptive events. Chapter 5 Resilience engineering 3" }, { "page_index": 245, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_004.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_004.png", "page_index": 245, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:03+07:00" }, "raw_text": "Essential resilience ideas Software Engineering The idea that some of the services offered by a system are critical services whose failure could have serious human, social or economic effects The idea that some events are disruptive and can affect the ability of a system to deliver its critical services. The idea that resilience is a judgment - there are no resilience metrics and resilience cannot be measured The resilience of a system can only be assessed by experts, who can examine the system and its operational processes. Chapter 5 Resilience engineering 4" }, { "page_index": 246, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_005.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_005.png", "page_index": 246, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:09+07:00" }, "raw_text": "Resilience engineering assumptions Software Engineering Resilience engineering assumes that it is impossible to avoid system failures and so is concerned with limiting the costs of these failures and recovering from them. Resilience engineering assumes that good reliability engineering practices have been used to minimize the number of technical faults in a system. It therefore places more emphasis on limiting the number of system failures that arise from external events such as operator errors or cyberattacks Chapter 5 Resilience engineering 5" }, { "page_index": 247, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_006.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_006.png", "page_index": 247, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:16+07:00" }, "raw_text": "Resilience activities Software Engineering Recognition: The system or its operators should recognise early indications of system failure. Resistance: If the symptoms of a problem or cyberattack are detected early, then resistance strategies may be used to reduce the probability that the system will fail. Recovery: If a failure occurs, the recovery activity ensures that critical system services are restored quickly so that system users are not badly affected by failure. Reinstatement: In this final activity, all of the system services are restored and normal system operation can continue Chapter 5 Resilience engineering 6" }, { "page_index": 248, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_007.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_007.png", "page_index": 248, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:23+07:00" }, "raw_text": "Resilience activities Software Engineering Recognition Resistance Recovery Reinstatement Normal operating Critical service Critical service Restricted service state delivery delivery delivery Attack Attack System Software and data recognition resistance repair restoration Attack Attack Repair detected successful complete Attack repelled Reinstatement complete Chapter 5 Resilience engineering 7" }, { "page_index": 249, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_008.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_008.png", "page_index": 249, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:25+07:00" }, "raw_text": "Software Engineering Cybersecurity Chapter 5 Resilience engineering 8" }, { "page_index": 250, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_009.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_009.png", "page_index": 250, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:32+07:00" }, "raw_text": "Cybersecurity Software Engineering Cybercrime is the illegal use of networked systems and is one of the most serious problems facing our society Cybersecurity is a broader topic than system security engineering Cybersecurity is a sociotchnical issue covering all aspects of ensuring the protection of citizens, businesses and critical infrastructures from threats that arise from their use of computers and the Internet. Cybersecurity is concerned with all of an organization's IT assets from networks through to application systems. Chapter 5 Resilience engineering 9" }, { "page_index": 251, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_010.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_010.png", "page_index": 251, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:38+07:00" }, "raw_text": "Factors contributing to cybersecurity failure Software Engineering organizational ignorance of the seriousness of the problem poor design and lax application of security procedures, human carelessness inappropriate trade-offs between usability and security Chapter 5 Resilience engineering 10" }, { "page_index": 252, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_011.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_011.png", "page_index": 252, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:44+07:00" }, "raw_text": "Cybersecurity threats Software Engineering Threats to the confidentiality of assets Data is not damaged but it is made available to people who should not have access to it. Threats to the integrity of assets s These are threats where systems or data are damaged in some way by a cyberattack. Threats to the availability of assets These are threats that aim to deny use of assets by authorized users. Chapter 5 Resilience engineering 11" }, { "page_index": 253, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_012.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_012.png", "page_index": 253, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:50+07:00" }, "raw_text": "Examples of controls Software Engineering Authentication, where users of a system have to show that they are authorized to access the system Encryption, where data is algorithmically scrambled so that an unauthorized reader cannot access the information. Firewalls, where incoming network packets are examined then accepted or rejected according to a set of organizational rules. Firewalls can be used to ensure that only traffic from trusted sources is passed from the external Internet into the Ioca organizational network Chapter 5 Resilience engineering 12" }, { "page_index": 254, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_013.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_013.png", "page_index": 254, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:15:57+07:00" }, "raw_text": "Redundancy and diversity Software Engineering Copies of data and software should be maintained on separate computer systems. This supports recovery after a successful cyberattack. (recovery and reinstatement) Multi-stage diverse authentication can protect against password attacks. This is a resistance measure Critical servers may be over-provisioned i.e. they may be more powerful than is required to handle their expected load. Attacks can be resisted without serious service degradation Chapter 5 Resilience engineering 13" }, { "page_index": 255, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_014.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_014.png", "page_index": 255, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:01+07:00" }, "raw_text": "Cyber-resilience planning Software Engineering Threat recognition Asset Threat Asset Asset classification identification recovery reinstatement Threat resistance Cyber-resilience plan Chapter 5 Resilience engineering 14" }, { "page_index": 256, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_015.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_015.png", "page_index": 256, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:07+07:00" }, "raw_text": "Cyber resilience planning Software Engineering Asset classification The organization's hardware, software and human assets are examined and classified depending on how essential they are to normal operations Threat identification For each of the assets (or, at least the critical and important assets), you should identify and classify threats to that asset. Threat recognition For each threat or, sometimes asset/threat pair, you should identify how an attack based on that threat might be recognised Chapter 5 Resilience engineering 15" }, { "page_index": 257, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_016.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_016.png", "page_index": 257, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:13+07:00" }, "raw_text": "Cyber resilience planning Software Engineering Threat resistance For each threat or asset/threat pair, you should identify possible resistance strategies. These may be either embedded in the system (technical strategies) or may rely on operational procedures. Asset recovery For each critical asset or asset/threat pair, you should work out how that asset could be recovered in the event of a successful cyberattack. Asset reinstatement This is a more general process of asset recovery where you define procedures to bring the system back into normal operation. Chapter 5 Resilience engineering 16" }, { "page_index": 258, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_017.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_017.png", "page_index": 258, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:17+07:00" }, "raw_text": "Systems approach Software Engineering Systems engineers should assume that human errors will occur during system operation. To improve the resilience of a system, designers have to think about the defences and barriers to human error that could be part of a system. Chapter 5 Resilience engineering 17" }, { "page_index": 259, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_018.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_018.png", "page_index": 259, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:21+07:00" }, "raw_text": "Defensive layers Software Engineering Technical defenses Errors or attacks Sociotechnical defenses Chapter 5 Resilience engineering 18" }, { "page_index": 260, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_019.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_019.png", "page_index": 260, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:26+07:00" }, "raw_text": "Defensive layers Software Engineering You should use redundancy and diversity to create a set of defensive layers, where each layer uses a different approach to deter attackers or trap technical/human failures Chapter 5 Resilience engineering 19" }, { "page_index": 261, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_020.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_020.png", "page_index": 261, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:32+07:00" }, "raw_text": "Reason's Swiss Cheese Model Software Engineering Active failure (Human error) Latent conditions in defensive layers System failure Chapter 5 Resilience engineering 20" }, { "page_index": 262, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_021.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_021.png", "page_index": 262, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:37+07:00" }, "raw_text": "Swiss Cheese model Software Engineering Defensive layers have vulnerabilities They are like slices of Swiss cheese with holes in the layer corresponding to these vulnerabilities. Vulnerabilities are dynamic The 'holes' are not always in the same place and the size of the holes may vary depending on the operating conditions. System failures occur when the holes line up and all of the defenses fail Chapter 5 Resilience engineering 21" }, { "page_index": 263, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_022.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_022.png", "page_index": 263, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:43+07:00" }, "raw_text": "Increasing system resilience Software Engineering Reduce the probability of the occurrence of an external event that might trigger system failures. Increase the number of defensive layers. The more layers that you have in a system, the less likely it is that the holes will line up and a system failure occur. Design a system so that diverse types of barriers are included The 'holes' will probably be in different places and so there is less chance of the holes lining up and failing to trap an error. Minimize the number of latent conditions in a system This means reducing the number and size of system 'holes'. Chapter 5 Resilience engineering 22" }, { "page_index": 264, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_023.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_023.png", "page_index": 264, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:46+07:00" }, "raw_text": "Software Engineering Resilient systems design Chapter 5 Resilience engineering 23" }, { "page_index": 265, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_024.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_024.png", "page_index": 265, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:52+07:00" }, "raw_text": "Resilient systems design Software Engineering Identifying critical services and assets Critical services and assets are those elements of the system that allow a system to fulfill its primary purpose. For example, the critical services in a system that handles ambulance dispatch are those concerned with taking calls and dispatching ambulances. 4 Designing system components that support problem recognition, resistance, recovery and reinstatement For example, in an ambulance dispatch system, a watchdog timer may be included to detect if the system is not responding to events. Chapter 5 Resilience engineering 24" }, { "page_index": 266, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_025.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_025.png", "page_index": 266, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:16:57+07:00" }, "raw_text": "Survivable systems analysis Software Engineering System understanding For an existing or proposed system, review the goals of the system (sometimes called the mission objectives), the system requirements and the system architecture. Critical service identification The services that must always be maintained and the components that are reguired to maintain these services are identified. Chapter 5 Resilience engineering 25" }, { "page_index": 267, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_026.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_026.png", "page_index": 267, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:03+07:00" }, "raw_text": "Survivable systems analysis Software Engineering Attack simulation Scenarios or use cases for possible attacks are identified along with the system components that would be affected by these attacks. Survivability analysis Components that are both essential and compromisable by an attack are identified and survivability strategies based on resistance, recognition and recovery are identified. Chapter 5 Resilience engineering 26" }, { "page_index": 268, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_027.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_027.png", "page_index": 268, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:08+07:00" }, "raw_text": "Stages in survivability analysis Software Engineering 1. Review system requirements and architecture 4. Identify softspots and 2. Identify critical services survivability strategies and components 3. Identify attacks and compromisable components Chapter 5 Resilience engineering 27" }, { "page_index": 269, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_028.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_028.png", "page_index": 269, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:18+07:00" }, "raw_text": "Resilience engineering Software Engineering Identify business resilience requirements Plan backup Plan system Develop software Reinstatement strategy reinstatement to support reinstatement Propose software changes Identify assets Identify events Plan event Recognition and Identify critical that deliver that compromise recognition and resistance services critical services assets resistance Buy new software required Plan critical Plan critical Design asset Develop software Recovery redundancy service recovery asset recovery to support strategy asset recovery Identify attack Testing Resilience test Test system Test service planning and failure resistance recovery scenarios Test system reinstatement Chapter 5 Resilience engineering 28" }, { "page_index": 270, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_029.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_029.png", "page_index": 270, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:23+07:00" }, "raw_text": "Streams of work in resilience engineering Software Engineering ldentify business resilience requirements Plan how to reinstate systems to their normal operating state ldentify system failures and cyberattacks that can compromise a system Plan how to recover critical services quickly after damage or a cyberattack Test all aspects of resilience planning Chapter 5 Resilience engineering 29" }, { "page_index": 271, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_030.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_030.png", "page_index": 271, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:27+07:00" }, "raw_text": "Mentcare system resilience Software Engineering The Mentcare system is a system used to support clinicians treating patients that suffer from mental health problems. It provides patient information and records of consultations with doctors and nurses. It includes checks that can flag patients who may be dangerous or suicidal. Y Based on a client-server architecture Chapter 5 Resilience engineering 30" }, { "page_index": 272, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_031.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_031.png", "page_index": 272, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:33+07:00" }, "raw_text": "Client-server architecture (Mentcare) Software Engineering Mentcare Mentcare Mentcare client client client Network Mentcare server Patient database Chapter 5 Resilience engineering 31" }, { "page_index": 273, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_032.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_032.png", "page_index": 273, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:38+07:00" }, "raw_text": "Critical Mentcare services Software Engineering An information service that provides information about a patient's current diagnosis and treatment plan. A warning service that highlights patients that could pose a danger to others or to themselves. Chapter 5 Resilience engineering 32" }, { "page_index": 274, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_033.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_033.png", "page_index": 274, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:44+07:00" }, "raw_text": "Assets reguired for normal service operation Software Engineering The patient record database that maintains all patient information. A database server that provides access to the database for local client computers Y A network for client/server communication. Local laptop or desktop computers used by clinicians to access patient information. A set of rules to identify patients who are potentially dangerous and which can flag patient records. Client software that highlights dangerous patients to system users. Chapter 5 Resilience engineering 33" }, { "page_index": 275, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_034.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_034.png", "page_index": 275, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:17:51+07:00" }, "raw_text": "Adverse events Software Engineering Unavailability of the database server either through a system failure, a network failure or a denial of service cyberattack Deliberate or accidental corruption of the patient record database or the rules that define what is meant by a dangerous patient' Infection of client computers with malware Access to client computers by unauthorized people who gain access to patient records Chapter 5 Resilience engineering 34" }, { "page_index": 276, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_035.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_035.png", "page_index": 276, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:03+07:00" }, "raw_text": "Recognition and resistance strategies Software Engineering Event Recognition Resistance Server unavailability 1. Watchdog timer on 1. Design system architecture to maintain local copies of client that times out if no critical information response to client access 2. Provide peer-to-peer search across clients for patient data 2. Text messages from 3. Provide staff with smart phones that can be used to access system managers to the network in the event of server failure clinical users 4, Provide backup server Patient database 1. Record level 1. Replayable transaction log to update database backup with corruption cryptographic checksums recent transactions 2. Regular auto-checking 2. Maintenance of local copies of patient information and of database integrity software to restore database from local copies and backups 3. Reporting system for incorrect information Malware infection of client 1. Reporting system so 1. Security awareness workshops for all system users computers that computer users can 2. Disabling of USB ports on client computers report unusual behaviour. 3. Automated system setup for new clients 2. Automated malware 4. Support access to system from mobile devices checks on startup 5. Installation of security software Unauthorized access to 1. Warning text messages 1. Multi-level system authentication process patient information from users about possible 2. Disabling of USB ports on client computers intruders 3. Access logging and real-time log analysis 2. Log analysis for 4. Security awareness workshops for all system users unusual activity Chapter 5 Resilience engineering 35" }, { "page_index": 277, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_036.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_036.png", "page_index": 277, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:09+07:00" }, "raw_text": "Mentcare system resilience Software Engineering Mentcare Mentcare Mentcare client client client Summary Summary Summary patient records patient records patient records Network Mentcare server Backup server Database Patient database integrity checker Transaction Database backup log Chapter 5 Resilience engineering 36" }, { "page_index": 278, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_037.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_037.png", "page_index": 278, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:16+07:00" }, "raw_text": "Architecture for resilience Software Engineering Summary patient records that are maintained on local client computers. The local computers can communicate directly with each other and exchange information using either the system network or using an ad hoc network created using mobile phones. If the database is unavailable, doctors and nurses can still access essential patient information. A backup server to allow for main server failure. This server is responsible for taking regular snapshots of the database as backups. In the event of the failure of the main server, it can also act as the main server for the whole system. Chapter 5 Resilience engineering 37" }, { "page_index": 279, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_038.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_038.png", "page_index": 279, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:20+07:00" }, "raw_text": "Architecture for resilience Software Engineering Database integrity checking and recovery software Integrity checking runs as a background task checking for signs of database corruption. If corruption is discovered, it can automatically initiate the recovery of some or all of the data from backups. The transaction log allows these backups to be updated with details of recent changes Chapter 5 Resilience engineering 38" }, { "page_index": 280, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_039.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_039.png", "page_index": 280, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:28+07:00" }, "raw_text": "Critical service maintenance Software Engineering By downloading information to the client at the start of a clinic session, the consultation can continue without server access Only the information about the patients who are scheduled to attend consultations that day needs to be downloaded. The service that provides a warning to staff of patients that may be dangerous can be implemented using this approach. The records of possibly patients who may harm themselves or others are identified before the download process. When clinical staff access these records, the software can highlight them to indicate that this is a patient that requires special care. Chapter 5 Resilience engineering 39" }, { "page_index": 281, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_040.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_040.png", "page_index": 281, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:34+07:00" }, "raw_text": "Risks to confidentiality Software Engineering To minimize risks to confidentiality that arise from multiple copies of information on laptops: Only download the summary records of patients who are scheduled to attend a clinic. This limits the numbers of records that could be compromised. Encrypt the disk on local client computers. An attacker who does not have the encryption key cannot read the disk if they gain access to the computer. Securely delete the downloaded information at the end of a clinic session. This further reduces the chances of an attacker gaining access to confidential information. Ensure that all network transactions are encrypted. If an attacker intercepts these transactions, they cannot get access to the information. Chapter 5 Resilience engineering 40" }, { "page_index": 282, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_041.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_041.png", "page_index": 282, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:42+07:00" }, "raw_text": "Key points Software Engineering Resilience is a judgment of how well a system can maintain the continuity of its critical services in the presence of disruptive events. Y Resilience should be based on the 4 R's model - recognition, resistance, recovery and reinstatement. Resilience planning should be based on the assumption of cyberattacks by malicious insiders and outsiders and that some of these attacks will be successful. Systems should be designed with defensive layers of different types. These layers trap human and technical failures and help resist cyberattacks. Chapter 5 Resilience engineering 41" }, { "page_index": 283, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_042.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_042.png", "page_index": 283, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:51+07:00" }, "raw_text": "Key points Software Engineering To allow system operators and managers to cope with problems, processes should be flexible and adaptable. Process automation can make it more difficult for people to cope with problems. Business resilience requirements should be the starting point for designing systems for resilience. To achieve system resilience, you have to focus on recognition and recovery from problems, recovery of critical services and assets and reinstatement of the system. An important part of design for resilience is identifying critical services. Systems should be designed so that these services are protected and, in the event of failure recovered as quicklyhasspossibleering 42" }, { "page_index": 284, "chapter_num": 5, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_043.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_5/slide_043.png", "page_index": 284, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:56+07:00" }, "raw_text": "Presentations (count as top 5) Software Engineering Software reuse Component-based software engineering Distributed software engineering Service-oriented software engineering Systems engineering Chapter 5 Resilience engineering 43" }, { "page_index": 285, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_001.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_001.png", "page_index": 285, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:18:58+07:00" }, "raw_text": "Software Engineering Chapter 6 - Software Reuse 17/11/2014 Chapter 15 Software reuse 1" }, { "page_index": 286, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_002.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_002.png", "page_index": 286, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:03+07:00" }, "raw_text": "Topics covered Software Engineering The reuse landscape Application frameworks Software product lines Application system reuse 17/11/2014 Chapter 15 Software reuse 2" }, { "page_index": 287, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_003.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_003.png", "page_index": 287, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:08+07:00" }, "raw_text": "Software reuse Software Engineering In most engineering disciplines, systems are designed by composing existing components that have been used in other systems. Software engineering has been more focused on original development but it is now recognised that to achieve better software, more quickly and at lower cost, we need a design process that is based on systematic software reuse. There has been a major switch to reuse-based development over the past 10 years. 17/11/2014 Chapter 15 Software reuse 3" }, { "page_index": 288, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_004.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_004.png", "page_index": 288, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:13+07:00" }, "raw_text": "Reuse-based software engineering Software Engineering System reuse Complete systems, which may include several application programs may be reused. Application reuse An application may be reused either by incorporating it without change into other or by developing application families. Component reuse Components of an application from sub-systems to single objects may be reused. Object and function reuse Small-scale software components that implement a single well- defined object or function may be reused. 17/11/2014 Chapter 15 Software reuse 4" }, { "page_index": 289, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_005.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_005.png", "page_index": 289, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:19+07:00" }, "raw_text": "Benefits of software reuse Software Engineering Benefit Explanation Accelerated development Bringing a system to market as early as possible is often more important than overall development costs. Reusing software can speed up system production because both development and validation time may be reduced. Effective use of specialists Instead of doing the same work over and over again, application specialists can develop reusable software that encapsulates their knowledge. Increased dependability Reused software, which has been tried and tested in working systems, should be more dependable than new software. Its design and implementation faults should have been found and fixed. 17/11/2014 Chapter 15 Software reuse S" }, { "page_index": 290, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_006.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_006.png", "page_index": 290, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:28+07:00" }, "raw_text": "Benefits of software reuse Software Engineering Benefit Explanation Lower development costs Development costs are proportional to the size of the software being developed. Reusing software means that fewer lines of code have to be written. Reduced process risk The cost of existing software is already known, whereas the costs of development are always a matter of judgment. This is an important factor for project management because it reduces the margin of error in project cost estimation. This is particularly true when relatively large software components such as subsystems are reused. Standards compliance Some standards, such as user interface standards, can be implemented as a set of reusable components. For example, if menus in a user interface are implemented using reusable components, all applications present the same menu formats to users. The use of standard user interfaces improves dependability because users make 17/11/2014 feweromistakesfwherpresented with a familiar interface. 6" }, { "page_index": 291, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_007.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_007.png", "page_index": 291, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:36+07:00" }, "raw_text": "Problems with reuse Software Engineering Problem Explanation Creating, maintaining Populating a reusable component library and ensuring the and using a component software developers can use this library can be expensive. library Development processes have to be adapted to ensure that the library is used. Finding, understanding Software components have to be discovered in a library and adapting reusable understood and, sometimes, adapted to work in a new components environment. Engineers must be reasonably confident of finding a component in the library before they include a component search as part of their normal development process. Increased maintenance If the source code of a reused software system or costs component is not available then maintenance costs may be higher because the reused elements of the system may become increasingly incompatible with system changes. 17/11/2014 Chapter 15 Software reuse 7" }, { "page_index": 292, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_008.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_008.png", "page_index": 292, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:43+07:00" }, "raw_text": "Problems with reuse Software Engineering Problem Explanation Lack of tool support Some software tools do not support development with reuse. It may be difficult or impossible to integrate these tools with a component library system. The software process assumed by these tools may not take reuse into account. This is particularly true for tools that support embedded systems engineering, less so for object- oriented development tools. Not-invented-here Some software engineers prefer to rewrite components syndrome because they believe they can improve on them. This is partly to do with trust and partly to do with the fact that writing original software is seen as more challenging than reusing other people's software. 17/11/2014 Chapter 15 Software reuse 8" }, { "page_index": 293, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_009.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_009.png", "page_index": 293, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:47+07:00" }, "raw_text": "Software Engineering The reuse landscape 17/11/2014 Chapter 15 Software reuse 9" }, { "page_index": 294, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_010.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_010.png", "page_index": 294, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:52+07:00" }, "raw_text": "The reuse landscape Software Engineering Although reuse is often simply thought of as the reuse of system components, there are many different approaches to reuse that may be used. Reuse is possible at a range of levels from simple functions to complete application systems. The reuse landscape covers the range of possible reuse techniques 17/11/2014 Chapter 15 Software reuse 10" }, { "page_index": 295, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_011.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_011.png", "page_index": 295, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:19:59+07:00" }, "raw_text": "The reuse landscape Software Engineering Design Architectural patterns patterns Application Software product Application ERP systems frameworks lines system integration Systems of Configurable Legacy system systems application systems wrapping Component-based Model-driven Service-oriented software engineering engineering systems Aspect-oriented Program Program software engineering libraries generators 17/11/2014 Chapter 15 Software reuse 11" }, { "page_index": 296, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_012.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_012.png", "page_index": 296, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:06+07:00" }, "raw_text": "Approaches that support software reuse Software Engineering Approach Description Application frameworks Collections of abstract and concrete classes are adapted and extended to create application systems. Application system Two or more application systems are integrated to provide integration extended functionality Architectural patterns Standard software architectures that support common types of application system are used as the basis of applications Described in Chapters 6, 11 and 17. Aspect-oriented software Shared components are woven into an application at different development places when the program is compiled. Described in web chapter 31. Component-based Systems are developed by integrating components software engineering (collections of objects) that conform to component-model standards. Described in Chapter 16. 17/11/2014 Chapter 15 Software reuse 12" }, { "page_index": 297, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_013.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_013.png", "page_index": 297, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:16+07:00" }, "raw_text": "Approaches that support software reuse Software Engineering Approach Description Configurable application Domain-specific systems are designed so that they can be systems configured to the needs of specific system customers. Design patterns Generic abstractions that occur across applications are represented as design patterns s showing abstract and concrete objects and interactions. Described in Chapter 7. ERP systems Large-scale systems that encapsulate generic business functionality and rules are configured for an organization. Legacy system wrapping Legacy systems (Chapter 9) are 'wrapped' by defining a set of interfaces and providing access to these legacy systems through these interfaces. Model-driven engineering Software is represented as domain models and implementation independent models and code is generated from these models. Described in Chapter 5 17/11/2014 Chapter 15 Software reuse 13" }, { "page_index": 298, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_014.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_014.png", "page_index": 298, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:23+07:00" }, "raw_text": "Approaches that support software reuse Software Engineering Approach Description Program generators A generator system embeds knowledge of a type of application and is used to generate systems in that domain from a user-supplied system model. Program libraries Class and function libraries that implement commonly used abstractions are available for reuse. Service-oriented systems Systems are developed by linking shared services, which may be externally provided. Described in Chapter 18. Software product lines An application type is generalized around a common architecture so that it can be adapted for different customers. Systems of systems Two or more distributed systems are integrated to create a new system. Described in Chapter 20. 17/11/2014 Chapter 15 Software reuse 14" }, { "page_index": 299, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_015.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_015.png", "page_index": 299, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:30+07:00" }, "raw_text": "Reuse planning factors Software Engineering The development schedule for the software The expected software lifetime. The background, skills and experience of the development team. The criticality of the software and its non-functional requirements. The application domain. The execution platform for the software. 17/11/2014 Chapter 15 Software reuse 15" }, { "page_index": 300, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_016.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_016.png", "page_index": 300, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:34+07:00" }, "raw_text": "Software Engineering Application frameworks 17/11/2014 Chapter 15 Software reuse 16" }, { "page_index": 301, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_017.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_017.png", "page_index": 301, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:40+07:00" }, "raw_text": "Framework definition Software Engineering \"..an integrated set of software artefacts (such as classes, objects and components) that collaborate to provide a reusable architecture for a family of related applications. 17/11/2014 Chapter 15 Software reuse 17" }, { "page_index": 302, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_018.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_018.png", "page_index": 302, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:47+07:00" }, "raw_text": "Application frameworks Software Engineering Frameworks are moderately large entities that can be reused. They are somewhere between system and component reuse. Frameworks are a sub-system design made up of a collection of abstract and concrete classes and the interfaces between them. The sub-system is implemented by adding components to fill in parts of the design and by instantiating the abstract classes in the framework 17/11/2014 Chapter 15 Software reuse 18" }, { "page_index": 303, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_019.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_019.png", "page_index": 303, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:52+07:00" }, "raw_text": "Web application frameworks Software Engineering Support the construction of dynamic websites as a front- end for web applications WAFs are now available for all of the commonly used web programming languages e.g. Java, Python, Ruby etc. Y Interaction model is based on the Model-View-Controller composite pattern. 17/11/2014 chapter 15 Software reuse 19" }, { "page_index": 304, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_020.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_020.png", "page_index": 304, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:20:56+07:00" }, "raw_text": "Model-yiew controller Software Engineering System infrastructure framework for GUl design. Allows for multiple presentations of an object and separate interactions with these presentations. Y MVC framework involves the instantiation of a number of patterns (as discussed in Chapter 7) 17/11/2014 Chapter 15 Software reuse 20" }, { "page_index": 305, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_021.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_021.png", "page_index": 305, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:02+07:00" }, "raw_text": "The Model-View-Controller pattern Software Engineering User view modification Controller state View state inputs messages Controller methods View methods Model queries and updates Model edits Model state Model methods 17/11/2014 Chapter 15 Software reuse 21" }, { "page_index": 306, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_022.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_022.png", "page_index": 306, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:09+07:00" }, "raw_text": "WAF features Software Engineering Security WAFs may include classes to help implement user authentication (login) and access. Dynamic web pages Classes are provided to help you define web page templates and to populate these dynamically from the system database. Database support The framework may provide classes that provide an abstract interface to different databases. Y Session management Classes to create and manage sessions (a number of interactions with the system by a user) are usually part of a WAF. User interaction Most web frameworks now provide AJAX support (Holdener, 2008), which allows more interactive web pages to be created. 17/11/2014 Chapter 15 Software reuse 22" }, { "page_index": 307, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_023.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_023.png", "page_index": 307, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:15+07:00" }, "raw_text": "Extending frameworks Software Engineering Frameworks are generic and are extended to create a more specific application or sub-system. They provide a skeleton architecture for the system. Extending the framework involves Adding concrete classes that inherit operations from abstract classes in the framework; Adding methods that are called in response to events that are recognised by the framework. Problem with frameworks is their complexity which means that it takes a long time to use them effectively. 17/11/2014 Chapter 15 Software reuse 23" }, { "page_index": 308, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_024.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_024.png", "page_index": 308, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:20+07:00" }, "raw_text": "Inversion of control in frameworks Software Engineering Event 0 GUI loop Callbacks Application specific classes Callbacks Callbacks Database Event Platform Event loop loop 17/11/2014 Chapter 15 Software reuse 24" }, { "page_index": 309, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_025.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_025.png", "page_index": 309, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:26+07:00" }, "raw_text": "Framework classes Software Engineering System infrastructure frameworks Support the development of system infrastructures such as communications, user interfaces and compilers Middleware integration frameworks Standards and classes that support component communication and information exchange. Enterprise application frameworks Support the development of specific types of application such as telecommunications or financial systems 17/11/2014 Chapter 15 Software reuse 25" }, { "page_index": 310, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_026.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_026.png", "page_index": 310, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:29+07:00" }, "raw_text": "Software Engineering Software product lines 17/11/2014 Chapter 15 Software reuse 26" }, { "page_index": 311, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_027.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_027.png", "page_index": 311, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:34+07:00" }, "raw_text": "Software product lines Software Engineering Software product lines or application families are applications with generic functionality that can be adapted and configured for use in a specific context. A software product line is a set of applications with a common architecture and shared components, with each application specialized to reflect different requirements. Adaptation may involve: Component and system configuration, Adding new components to the system; Selecting from a library of existing components; Modifying components to meet new requirements. 17/11/2014 Chapter 15 Software reuse 27" }, { "page_index": 312, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_028.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_028.png", "page_index": 312, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:38+07:00" }, "raw_text": "Base systems for a software product line Software Engineering Specialized application components Configurable application components Core components 17/11/2014 Chapter 15 Software reuse 28" }, { "page_index": 313, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_029.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_029.png", "page_index": 313, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:44+07:00" }, "raw_text": "Base applications Software Engineering Core components that provide infrastructure support. These are not usually modified when developing a new instance of the product line Configurable components that may be modified and configured to specialize them to a new application. Sometimes, it is possible to reconfigure these components without changing their code by using a built- in component configuration language. Specialized, domain-specific components some or all of which may be replaced when a new instance of a product line is created. 17/11/2014 Chapter 15 Software reuse 29" }, { "page_index": 314, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_030.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_030.png", "page_index": 314, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:50+07:00" }, "raw_text": "Application frameworks and product lines Software Engineering Application frameworks rely on object-oriented features such as polymorphism to implement extensions. Product lines need not be object-oriented (e.g. embedded software for a mobile phone Application frameworks focus on providing technical rather than domain-specific support. Product lines embed domain and platform information Product lines often control applications for equipment Software product lines are made up of a family of applications, usually owned by the same organization. 17/11/2014 Chapter 15 Software reuse 30" }, { "page_index": 315, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_031.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_031.png", "page_index": 315, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:21:55+07:00" }, "raw_text": "Product line architectures Software Engineering Architectures must be structured in such a way to separate different sub-systems and to allow them to be modified The architecture should also separate entities and their descriptions and the higher levels in the system access entities through descriptions rather than directly 17/11/2014 Chapter 15 Software reuse 31" }, { "page_index": 316, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_032.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_032.png", "page_index": 316, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:02+07:00" }, "raw_text": "The architecture of a resource allocation system Software Engineering Interaction User interface /0 management User Resource Query authentication delivery management Resource management Resource Resource policy Resource tracking allocation control Database management Transaction management Resource database 17/11/2014 Chapter 15 Software reuse 32" }, { "page_index": 317, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_033.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_033.png", "page_index": 317, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:09+07:00" }, "raw_text": "The product line architecture of a vehicle dlspatcher Software Engineering Interaction Comms system Operator interface interface l/0 management Map and route Report Operator Query authentication planner generator manager Resource management Vehicle status Incident Vehicle Equipment Vehicle logger despatcher manager locator manager Database management Incident log Transaction management Equipment database Vehicle database Map database 17/11/2014 Chapter 15 Software reuse 33" }, { "page_index": 318, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_034.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_034.png", "page_index": 318, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:17+07:00" }, "raw_text": "Vehicle dispatching Software Engineering A specialised resource management system where the aim is to allocate resources (vehicles) to handle incidents. Adaptations include: At the Ui level, there are components for operator display and communications, At the I/O management level, there are components that handle authentication, reporting and route planning At the resource management level, there are components for vehicle location and despatch, managing vehicle status and incident logging; The database includes equipment, vehicle and map databases 17/11/2014 Chapter 15 Software reuse 34" }, { "page_index": 319, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_035.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_035.png", "page_index": 319, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:23+07:00" }, "raw_text": "Product line specialisation Software Engineering Platform specialization Different versions of the application are developed for different platforms. Environment specialization Different versions of the application are created to handle different operating environments e.g. different types of communication eguipment Functional specialization Different versions of the application are created for customers with different reguirements. Process specialization Different versions of the application are created to support different business processes. 17/11/2014 Chapter 15 Software reuse 35" }, { "page_index": 320, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_036.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_036.png", "page_index": 320, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:28+07:00" }, "raw_text": "Product instance development Software Engineering Renegotiate requirements Elicit Choose stakeholder closest-fit requirements system instance Adapt existing Deliver new system system instance 17/11/2014 Chapter 15 Software reuse 36" }, { "page_index": 321, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_037.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_037.png", "page_index": 321, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:34+07:00" }, "raw_text": "Product instance development Software Engineering Elicit stakeholder requirements Use existing family member as a prototype Choose closest-fit family member Find the family member that best meets the requirements Re-negotiate requirements Adapt requirements as necessary to capabilities of the software Adapt existing system Develop new modules and make changes for family member Deliver new family member Document key features for further member development 17/11/2014 Chapter 15 Software reuse 37" }, { "page_index": 322, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_038.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_038.png", "page_index": 322, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:42+07:00" }, "raw_text": "Product line configuration Software Engineering Design time configuration The organization that is developing the software modifies a common product line core by developing, selecting or adapting components to create a new system for a customer. Deployment time configuration A generic system is designed for configuration by a customer or consultants working with the customer. Knowledge of the customer's specific requirements and the system's operating environment is embedded in configuration data that are used by the generic system 17/11/2014 Chapter 15 Software reuse 38" }, { "page_index": 323, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_039.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_039.png", "page_index": 323, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:47+07:00" }, "raw_text": "Deployment-time configuration Software Engineering Configuration planning tool Generic system Configuration database System database 17/11/2014 Chapter 15 Software reuse 39" }, { "page_index": 324, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_040.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_040.png", "page_index": 324, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:55+07:00" }, "raw_text": "Levels of deployment time configuration Software Engineering Component selection, where you select the modules in a system that provide the required functionality. Workflow and rule definition, where you define workflows (how information is processed, stage-by-stage) and validation rules that should apply to information entered by users or generated by the system. Parameter definition, where you specify the values of specific system parameters that reflect the instance of the application that you are creating 17/11/2014 Chapter 15 Software reuse 40" }, { "page_index": 325, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_041.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_041.png", "page_index": 325, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:22:59+07:00" }, "raw_text": "Software Engineering Application system reuse 17/11/2014 Chapter 15 Software reuse 41" }, { "page_index": 326, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_042.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_042.png", "page_index": 326, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:07+07:00" }, "raw_text": "Application system reuse Software Engineering An application system product is a software system that can be adapted for different customers without changing the source code of the system. Application systems have generic features and so can be used/reused in different environments. Application system products are adapted by using built- in configuration mechanisms that allow the functionality of the system to be tailored to specific customer needs. For example, in a hospital patient record system, separate input forms and output reports might be defined for different types of patient. 17/11/2014 Chapter 15 Software reuse 42" }, { "page_index": 327, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_043.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_043.png", "page_index": 327, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:17+07:00" }, "raw_text": "Benefits of application system reuse Software Engineering As with other types of reuse, more rapid deployment of a reliable system may be possible. It is possible to see what functionality is provided by the applications and so it is easier to judge whether or not they are likely to be suitable. Some development risks are avoided by using existing software However, this approach has its own risks, as I discuss below. Businesses can focus on their core activity without having to devote a lot of resources to IT systems development As operating platforms evolve, technology updates may be simplified as these are the responsibility of the COTS product vendor rather than the customer. 17/11/2014 Chapter 15 Software reuse 43" }, { "page_index": 328, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_044.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_044.png", "page_index": 328, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:25+07:00" }, "raw_text": "Problems of application system reuse Software Engineering Requirements usually have to be adapted to reflect the functionality and mode of operation of the COTS product The COTS product may be based on assumptions that are practically impossible to change. Choosing the right COTS system for an enterprise can be a difficult process, especially as many COTS products are not well documented There may be a lack of local expertise to support systems development The COTS product vendor controls system support and evolution. 17/11/2014 Chapter 15 Software reuse 44" }, { "page_index": 329, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_045.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_045.png", "page_index": 329, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:33+07:00" }, "raw_text": "Configurable application systems Software Engineering Configurable application systems are generic application systems that may be designed to support a particular business type, business activity or, sometimes, a complete business enterprise. For example, an application system may be produced for dentists that handles appointments, dental records, patient recall, etc. Domain-specific systems, such as systems to support a business function (e.g. document management) provide functionality that is likely to be required by a range of potential users. 17/11/2014 Chapter 15 Software reuse 45" }, { "page_index": 330, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_046.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_046.png", "page_index": 330, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:42+07:00" }, "raw_text": "COTS-solution and COTS-integrated systems Software Engineering Configurable application systems Application system integration Single product that provides the Several heterogeneous system products functionality required by a customer are integrated to provide customized functionality Based around a generic solution and Flexible solutions may be developed for standardized processes customer processes Development focus is on system Development focus is on system integration configuration System vendor is responsible for System owner is responsible for maintenance maintenance System vendor provides the platform for the System owner provides the platform for the system system 17/11/2014 Chapter 15 Software reuse 46" }, { "page_index": 331, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_047.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_047.png", "page_index": 331, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:47+07:00" }, "raw_text": "ERP systems Software Engineering An Enterprise Resource Planning (ERP) system is a generic system that supports common business processes such as ordering and invoicing. manufacturing, etc These are very widely used in large companies - they represent probably the most common form of software reuse. The generic core is adapted by including modules and by incorporating knowledge of business processes and rules. 17/11/2014 Chapter 15 Software reuse 47" }, { "page_index": 332, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_048.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_048.png", "page_index": 332, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:52+07:00" }, "raw_text": "The architecture of an ERP system Software Engineering Purchasing Supply chain Logistics CRM Processes Processes Processes Processes Business rules System database 17/11/2014 Chapter 15 Software reuse 48" }, { "page_index": 333, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_049.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_049.png", "page_index": 333, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:23:59+07:00" }, "raw_text": "ERP architecture Software Engineering A number of modules to support different business functions A defined set of business processes, associated with each module, which relate to activities in that module A common database that maintains information about all related business functions A set of business rules that apply to all data in the database 17/11/2014 Chapter 15 Software reuse 49" }, { "page_index": 334, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_050.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_050.png", "page_index": 334, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:06+07:00" }, "raw_text": "ERP configuration Software Engineering Selecting the required functionality from the system. Establishing a data model that defines how the organization's data will be structured in the system database. Defining business rules that apply to that data. Defining the expected interactions with external systems Designing the input forms and the output reports generated by the system. Designing new business processes that conform to the underlying process model supported by the system. Setting parameters that define how the system is deployed on its underlying platform. 17/11/2014 Chapter 15 Software reuse 50" }, { "page_index": 335, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_051.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_051.png", "page_index": 335, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:12+07:00" }, "raw_text": "Integrated application systems Software Engineering Integrated application systems are applications that include two or more application system products and/or legacy application systems. You may use this approach when there is no single application system that meets all of your needs or when you wish to integrate a new application system with systems that you already use. 17/11/2014 Chapter 15 Software reuse 51" }, { "page_index": 336, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_052.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_052.png", "page_index": 336, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:18+07:00" }, "raw_text": "Design choices Software Engineering Which individual application systems offer the most appropriate functionality? Typically, there will be several application system products available, which can be combined in different ways. How will data be exchanged? Different products normally use unigue data structures and formats. You have to write adaptors that convert from one representation to another. What features of a product will actually be used? Individual application systems may include more functionality than you need and functionality may be duplicated across different products 17/11/2014 Chapter 15 Software reuse 52" }, { "page_index": 337, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_053.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_053.png", "page_index": 337, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:26+07:00" }, "raw_text": "An integrated procurement system Software Engineering Client Web browser E-mail system Server E-commerce Ordering and Adaptor system invoicing system Adaptor E-mail system 17/11/2014 Chapter 15 Software reuse 53" }, { "page_index": 338, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_054.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_054.png", "page_index": 338, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:32+07:00" }, "raw_text": "Service-oriented interfaces Software Engineering Application system integration can be simplified if a service-oriented approach is used. A service-oriented approach means allowing access to the application system's functionality through a standard service interface, with a service for each discrete unit of functionality Some applications may offer a service interface but sometimes, this service interface has to be implemented by the system integrator. You have to program a wrapper that hides the application and provides externally visible services 17/11/2014 Chapter 15 Software reuse 54" }, { "page_index": 339, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_055.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_055.png", "page_index": 339, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:38+07:00" }, "raw_text": "Application wrapping Software Engineering Service wrapper Application system Services Services 17/11/2014 Chapter 15 Software reuse 55" }, { "page_index": 340, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_056.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_056.png", "page_index": 340, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:44+07:00" }, "raw_text": "Application system integration problems Software Engineering Lack of control over functionality and performance Application systems may be less effective than they appear Problems with application system inter-operability Different application systems may make different assumptions that means integration is difficult No control over system evolution Application system vendors not system users control evolution Support from system vendors Application system vendors may not offer support over the lifetime of the product 17/11/2014 Chapter 15 Software reuse 56" }, { "page_index": 341, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_057.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_057.png", "page_index": 341, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:54+07:00" }, "raw_text": "Key points Software Engineering There are many different ways to reuse software. These range from the reuse of classes and methods in libraries to the reuse of complete application systems The advantages of software reuse are lower costs, faster software development and lower risks. System dependability is increased. Specialists can be used more effectively by concentrating their expertise on the design of reusable components. Application frameworks are collections of concrete and abstract objects that are designed for reuse through specialization and the addition of new objects. They usually incorporate good design practice through design patterns. 17/11/2014 Chapter 15 Software reuse 57" }, { "page_index": 342, "chapter_num": 6, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_058.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_6/slide_058.png", "page_index": 342, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:24:59+07:00" }, "raw_text": "Key points Software Engineering Software product lines are related applications that are developed from one or more base applications. A generic system is adapted and specialized to meet specific reguirements for functionality, target platform or operational configuration. Application system reuse is concerned with the reuse of large-scale off-the-shelf systems. These provide a lot of functionality and their reuse can radically reduce costs and development time. Systems may be developed by configuring a single, generic application system or by integrating two or more application systems. Potential problems with application system reuse include lack of control over functionality and performance, lack of control over system evolution, the need for support from external vendors and difficulties in ensuring that systems can inter-operate. 17/11/2014 Chapter 15 Software reuse 58" }, { "page_index": 343, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_001.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_001.png", "page_index": 343, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:05+07:00" }, "raw_text": "Software Engineering Chapter 11 - Systems of Systems Chapter 11 Systems of Systems 1" }, { "page_index": 344, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_002.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_002.png", "page_index": 344, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:10+07:00" }, "raw_text": "Topics covered Software Engineering System complexity System of systems classification Reductionism and complex systems Systems of systems engineering Systems of systems architecture Chapter 11 Systems of Systems 2" }, { "page_index": 345, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_003.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_003.png", "page_index": 345, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:15+07:00" }, "raw_text": "Systems of systems Software Engineering More and more systems are being constructed by integrated existing, independent systems 4 A system of systems is a system that contains two or more independently managed elements There is no single manager for all of the parts of the system of systems and that different parts of a system are subject to different management and control policies and rules Chapter 11 Systems of Systems" }, { "page_index": 346, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_004.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_004.png", "page_index": 346, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:21+07:00" }, "raw_text": "Examples of systems of systems Software Engineering A cloud management system that handles local private cloud management and management of servers on public clouds such as Amazon and Microsoft An online banking system that handles loan requests and which connects to a credit reference system provided by credit reference agency to check the credit of applicants. An emergency information system that integrates information from police, ambulance, fire and coastguard services about the assets available to deal with civil emergencies such as flooding and large-scale accidents. Chapter 11 Systems of Systems 4" }, { "page_index": 347, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_005.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_005.png", "page_index": 347, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:30+07:00" }, "raw_text": "Essential characteristics of SoS Software Engineering Operational independence of system elements Managerial independence of system elements Evolutionary development Emergence of system characteristics Geographic distribution of system elements Data intensive (data >> code) Heterogeneity Chapter 11 Systems of Systems 5" }, { "page_index": 348, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_006.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_006.png", "page_index": 348, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:33+07:00" }, "raw_text": "Software Engineering System complexity Chapter 11 Systems of Systems 6" }, { "page_index": 349, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_007.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_007.png", "page_index": 349, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:40+07:00" }, "raw_text": "Complexity Software Engineering All systems are composed of parts (elements) with relationships between these elements of the system. For example, the parts of a program may be objects and the parts of each object may be constants, variables and methods. Examples of relationships include calls' (method A calls method B), inherits-from' (object X inherits the methods and attributes of object Y) and 'part of' (method A is part of object X) The complexity of any system depends on the number and the types of relationships between system elements The type of relationship (static or dynamic) also influences the overall complexity of a system Chapter 11 Systems of Systems 7" }, { "page_index": 350, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_008.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_008.png", "page_index": 350, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:46+07:00" }, "raw_text": "Simple and complex systems Software Engineering System (a) System (b) Chapter 11 Systems of Systems 8" }, { "page_index": 351, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_009.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_009.png", "page_index": 351, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:52+07:00" }, "raw_text": "Process complexity Software Engineering As systems grow in size, they need more complex production and management processes. Complex processes are themselves complex systems. They are difficult to understand and may have undesirable emergent properties. They are more time consuming than simpler processes and they require more documentation and coordination between the people and the organizations involved in the system development. The complexity of the production process is one of the main reasons why projects go wrong, with software delivered late and over-budget Chapter 11 Systems of Systems 9" }, { "page_index": 352, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_010.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_010.png", "page_index": 352, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:25:57+07:00" }, "raw_text": "System production and management processes Software Engineering Production process Management process Produces Manages Complex system Chapter 11 Systems of Systems 10" }, { "page_index": 353, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_011.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_011.png", "page_index": 353, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:06+07:00" }, "raw_text": "Complexity and software engineering Software Engineering Complexity is important for software engineering because it is the main influence on the understandability and the changeability of a system The more complex a system, the more difficult it is to understand and analyze As complexity increases, there are more and more relationships between elements of the system and an increased likelihood that changing one part of a system will have undesirable effects elsewhere Chapter 11 Systems of Systems 11" }, { "page_index": 354, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_012.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_012.png", "page_index": 354, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:12+07:00" }, "raw_text": "Types of complexity Software Engineering Technical complexity is derived from the relationships between the different components of the system itself. Managerial complexity is derived from the complexity of the relationships between the system and its managers and the relationships between the managers of different parts of the system. Governance complexity of a system depends on the relationships between the laws, regulations and policies that affect the system and the relationships between the decision-making processes in the organizations responsible for the system. Chapter 11 Systems of Systems 12" }, { "page_index": 355, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_013.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_013.png", "page_index": 355, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:18+07:00" }, "raw_text": "System characteristics and complexity Software Engineering SoS characteristic Technical Managerial Governance complexity complexity complexity Operational x x independence Managerial x x independence Evolutionary x development Emergence x Geographical x x x distribution Data-intensive x x Heterogeneity x Chapter 11 Systems of Systems 13" }, { "page_index": 356, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_014.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_014.png", "page_index": 356, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:24+07:00" }, "raw_text": "Complexity and project failure Software Engineering Large-scale systems of systems are now unimaginably complex entities that cannot be understood or analyzed as a whole. The large number of interactions between the parts and the dynamic nature of these interactions means that conventional engineering approaches do not work well for complex systems. It is complexity that is the root cause of problems in projects to develop large software-intensive systems, not poor management or technical failings. Chapter 11 Systems of Systems 14" }, { "page_index": 357, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_015.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_015.png", "page_index": 357, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:27+07:00" }, "raw_text": "Software Engineering Systems of systems classification Chapter 11 Systems of Systems 15" }, { "page_index": 358, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_016.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_016.png", "page_index": 358, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:37+07:00" }, "raw_text": "Maier's classification of systems of systems Software Engineering Directed SoS are owned by a single organization and are developed by integrating systems that are also owned by that organization. The system elements may be independently managed by parts of the organization. Collaborative SoS are systems where there is no central authority to set management priorities and resolve disputes. Typically, elements of the system are owned and governed by different organizations. Virtual systems have no central governance and the participants may not agree on the overall purpose of the system. Participant systems may enter or leave the SoS Chapter 11 Systems of Systems 16" }, { "page_index": 359, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_017.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_017.png", "page_index": 359, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:45+07:00" }, "raw_text": "More intuitive classification terms Software Engineering Organizational systems of systems are SoS where the governance and management of the system lies within the same organization or company. Federated systems are SoS where the governance of the SoS depends on a voluntary participative body in which all of the system owners are represented. System of system coalitions are SoS where there are no formal governance mechanisms but where the organizations involved informally collaborate and manage their own systems to maintain the system as a whole. Chapter 11 Systems of Systems 17" }, { "page_index": 360, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_018.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_018.png", "page_index": 360, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:51+07:00" }, "raw_text": "System of systems classification Software Engineering Organizational Federated Coalition 3 Governance 1 2 3 123 Management 1]2]3 Technical 2 3 Chapter 11 Systems of Systems 18" }, { "page_index": 361, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_019.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_019.png", "page_index": 361, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:26:56+07:00" }, "raw_text": "iLearn as a SoS Software Engineering iLearn is a relatively simple technical system but it has a high level of governance complexity The development of a digital learning system is a national initiative but to create a digital learning environment, it has to be integrated with network management and school administration systems. There is no common governance process across authorities so, according to the classification scheme this is a coalition of systems. Chapter 11 Systems of Systems 19" }, { "page_index": 362, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_020.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_020.png", "page_index": 362, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:00+07:00" }, "raw_text": "Software Engineering Reductionism and complex systems Chapter 11 Systems of Systems 20" }, { "page_index": 363, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_021.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_021.png", "page_index": 363, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:07+07:00" }, "raw_text": "Complexity management in engineering Software Engineering The approach that has been the basis of complexity management in software engineering is called reductionism Reductionism is based on the assumption that any system is made up of parts or subsystems. It assumes that the behaviour and properties of the system as a whole can be understood and predicted by understanding the individual parts and the relationships between these parts To design a system, the parts making up that system are identified, constructed separately and then assembled into the complete system. Chapter 11 Systems of Systems 21" }, { "page_index": 364, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_022.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_022.png", "page_index": 364, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:15+07:00" }, "raw_text": "Software engineering methods Software Engineering A reductionist approach has been the basis of software engineering for almost 50 years. Top-down design, where you start with a very high-level model of a system and break this down to its components is a reductionist approach. This is the basis of all software design methods, such as object- oriented design. Programming languages include abstractions, such as procedures and objects that directly reflect reductionist system decomposition. Agile methods are also reductionist. The difference between agile methods and top-down design is that system decomposition is incremental when an agile approach is used. Chapter 11 Systems of Systems 22" }, { "page_index": 365, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_023.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_023.png", "page_index": 365, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:22+07:00" }, "raw_text": "Reductionist methods Software Engineering Reductionist methods are successful when there are relatively few relationships between the parts of a system and it is possible to model these relationships Software engineering methods attempt to limit complexity by controlling the relationships between parts of the system. Reductionism does not work well when there are many relationships in a system and when these relationships are difficult to understand and analyze The fundamental assumptions that are inherent to reductionism are inapplicable for large and complex systems Chapter 11 Systems of Systems 23" }, { "page_index": 366, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_024.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_024.png", "page_index": 366, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:30+07:00" }, "raw_text": "Reductionist assumptions Software Engineering 4 System ownership and control Reductionism assumes that there is a controlling authority for a system that can resolve disputes and make high-level technical decisions that will apply across the system. Rational decision making Reductionism assumes that interactions between components can be objectively assessed by, for example, mathematical modelling Defined system boundaries Reductionism assumes that the boundaries of a system can be agreed and defined. Chapter 11 Systems of Systems 24" }, { "page_index": 367, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_025.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_025.png", "page_index": 367, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:41+07:00" }, "raw_text": "System of systems reality Software Engineering Control Decision making Problem definition Decisions are made Owners of a There is a definable rationally, driven system control problem and clear by technical criteria its development system boundaries Reductionist assumptions There is no single Decision-making Wicked problem with system owner driven by political constantly renegotiated or controller motives system boundaries Systems of systems reality Chapter 11 Systems of Systems 25" }, { "page_index": 368, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_026.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_026.png", "page_index": 368, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:48+07:00" }, "raw_text": "Reductionism and software SoS Software Engineering Relationships in software systems are not governed by physical laws. Political factors are usually the driver of decision making for large and complex software systems. Software has no physical limitations hence there are no limits on where the boundaries of a system are drawn. The boundaries and the scope of a system are likely to change during its development. Linking software systems from different owners is relatively easy hence we are more likely to try and create a SoS where there is no single governing body Chapter 11 Systems of Systems 26" }, { "page_index": 369, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_027.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_027.png", "page_index": 369, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:52+07:00" }, "raw_text": "Software Engineering Systems of systems engineering Chapter 11 Systems of Systems 27" }, { "page_index": 370, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_028.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_028.png", "page_index": 370, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:27:58+07:00" }, "raw_text": "SoS engineering problems Software Engineering Lack of control over system functionality and performance. Differing and incompatible assumptions made by the developers of the different systems. Different evolution strategies and timetables for the different systems Lack of support from system owners when problems arise. Chapter 11 Systems of Systems 28" }, { "page_index": 371, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_029.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_029.png", "page_index": 371, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:03+07:00" }, "raw_text": "Systems of systems engineering Software Engineering Systems knowledge System selection Conceptual Interface Integration and design development deployment Architectural design Governance and management policy setting Chapter 11 Systems of Systems 29" }, { "page_index": 372, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_030.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_030.png", "page_index": 372, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:09+07:00" }, "raw_text": "SoS development processes Software Engineering Conceptual design is the activity of creating a high-level vision for a system, defining essential requirements and identifying constraints on the overall system. System selection, where a set of systems for inclusion in the SoS is chosen. Political imperatives and issues of system governance and management are often the key factors that influence what systems are included in a SoS Architectural design where an overall architecture for the SoS is developed. Chapter 11 Systems of Systems 30" }, { "page_index": 373, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_031.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_031.png", "page_index": 373, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:16+07:00" }, "raw_text": "SoS development processes Software Engineering Interface development - the development of system interfaces so that the constituent systems can Interoperate Integration and deployment - making the different systems involved in the SoS work together and interoperate through the developed interfaces. System deployment means putting the system into place in the organizations concerned and making it operational. Chapter 11 Systems of Systems 31" }, { "page_index": 374, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_032.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_032.png", "page_index": 374, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:24+07:00" }, "raw_text": "Interface development Software Engineering In general, the aim in SoS development is for systems to be able to communicate directly with each other without user intervention. Service interfaces If systems in a SoS have service interfaces, they can communicate directly via these interfaces The constituent systems in a SoS often have their own specialized API or only allow their functionality to be accessed through their user interfaces. You therefore have to develop software that reconciles the differences between these interfaces. Chapter 11 Systems of Systems 32" }, { "page_index": 375, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_033.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_033.png", "page_index": 375, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:30+07:00" }, "raw_text": "Service interface development Software Engineering To develop service-based interfaces, you have to examine the functionality of existing systems and define a set of services to reflect that functionality. The services are implemented either by calls to the underlying system API or by mimicking user interaction with the system. A principal system acts as a service broker, directing service calls between the different systems in the SoS. Each system therefore does not need to know which other system is providing a called service. Chapter 11 Systems of Systems 33" }, { "page_index": 376, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_034.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_034.png", "page_index": 376, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:34+07:00" }, "raw_text": "Service interfaces Software Engineering Service interfaces System 1 Unified service Interface Principal System 2 system System 3 Chapter 11 Systems of Systems 34" }, { "page_index": 377, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_035.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_035.png", "page_index": 377, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:39+07:00" }, "raw_text": "Unified user interfaces Software Engineering User interfaces for each system in a SoS are likely to be different A principal system must have some overall user interfaces that handles user authentication and provides access to the features of the underlying system. It is usually expensive and time-consuming to implement a unified user interface to replace the individual interfaces of the underlying systems Chapter 11 Systems of Systems 35" }, { "page_index": 378, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_036.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_036.png", "page_index": 378, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:46+07:00" }, "raw_text": "Cost-effectiveness of Ul development Software Engineering The interaction assumptions of the systems in the SoS If systems have different interaction models, unifying these in a single UI is very difficult Y The mode of use of the SoS A unified Ul slows down interaction if most of the interaction is with a principal system in the SoS The 'openness' of the SoS If the SoS is open, so that new systems may be added to it when it is in use, then unified Ul development is impractical. Chapter 11 Systems of Systems 36" }, { "page_index": 379, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_037.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_037.png", "page_index": 379, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:52+07:00" }, "raw_text": "Integration and deployment Software Engineering For SoS, it makes sense to consider integration and deployment to be part of the same process. Separate integration may be difficult as some of the systems in the SoS may already be in use The integration process should begin with systems that are already deployed, with new systems added to the SoS to provide coherent additions to the functionality of the overall system. Chapter 11 Systems of Systems 37" }, { "page_index": 380, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_038.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_038.png", "page_index": 380, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:28:58+07:00" }, "raw_text": "Staged deployment of the iLearn system Software Engineering The initial deployment provides authentication, basic learning functionality and integration with school administration systems. Stage 2 adds an integrated storage system and a set of more specialized tools to support subject-specific learning Stage 3 adds features for user configuration and the ability for users to add new systems to the iLearn environment Chapter 11 Systems of Systems 38" }, { "page_index": 381, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_039.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_039.png", "page_index": 381, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:06+07:00" }, "raw_text": "iLearn releases Software Engineering Release timeline Programming Office 365 Data analysis tools environments ibook tools School admin systems Science simulation systems Google Apps Content systems Learning portfolio system (history, languages, etc.) Age-specific tools Wordpress Drawing and photo tools iLearn V2 tools Conferencing system iLearn V1 tools Configuration system Moodle VLE Storage system Storage system Authentication system Authentication system Authentication system iLearn V1 iLearn V2 iLearn V3 Chapter 11 Systems of Systems 39" }, { "page_index": 382, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_040.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_040.png", "page_index": 382, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:13+07:00" }, "raw_text": "SoS testing Software Engineering There are three reasons why testing systems of systems is difficult and expensive: There may not be a detailed requirements specification that can be used as a basis for system testing. It may not be cost effective to develop a SoS requirements document - the details of the system functionality are defined by the systems included. The constituent systems may change in the course of the testing process so tests may not be repeatable. If problems are discovered, it may not be possible to fix the problems by requiring one of more of the constituent systems to be changed. Intermediate software may have to be introduced to solve the problem Chapter 11 Systems of Systems 40" }, { "page_index": 383, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_041.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_041.png", "page_index": 383, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:19+07:00" }, "raw_text": "SoS testing and agile testing Software Engineering Agile methods do not rely on having a complete system specification for system acceptance testing Stakeholders are engaged with the testing process and to decide when the overall system is acceptable. For SoS, a range of stakeholders should be involved in the testing process if possible and they can comment on whether or not the system is ready for deployment. Agile methods make extensive use of automated testing. This makes it much easier to rerun tests to discover if unexpected system changes have caused problems for the SoS as a whole. Chapter 11 Systems of Systems 41" }, { "page_index": 384, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_042.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_042.png", "page_index": 384, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:24+07:00" }, "raw_text": "Software Engineering Systems of systems architecture Chapter 11 Systems of Systems 42" }, { "page_index": 385, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_043.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_043.png", "page_index": 385, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:29+07:00" }, "raw_text": "General principles for architecting SoS Software Engineering Design systems so that they can deliver value if they are incomplete Be realistic about what can be controlled Focus on the system interfaces Provide collaboration incentives Design a SoS as node and web architecture. Specify behaviour as services exchanged between nodes. Understand and manage system vulnerabilities. Chapter 11 Systems of Systems 43" }, { "page_index": 386, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_044.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_044.png", "page_index": 386, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:35+07:00" }, "raw_text": "Architectural frameworks Software Engineering Y Architectural frameworks such as MODAFand TOGAF have been suggested as a means to support the architectural design of systems of systems. An architecture framework recognises that a single model of an architecture does not present all of the information needed for architectural and business analysis Frameworks propose a number of architectural views that should be created and maintained to describe and document enterprise systems. Chapter 11 Systems of Systems 44" }, { "page_index": 387, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_045.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_045.png", "page_index": 387, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:42+07:00" }, "raw_text": "TOGAF Software Engineering The TOGAF framework has been developed by the Open Group as an open standard and is intended to support the design of a business architecture, a data architecture, an application architecture and a technology architecture for an enterprise. At its heart is the Architecture Development Method (ADM), which consists of a number of discrete phases. Chapter 11 Systems of Systems 45" }, { "page_index": 388, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_046.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_046.png", "page_index": 388, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:49+07:00" }, "raw_text": "TOGAF - Architecture Development Method Software Engineering Preliminary A. Architecture vision H. B. Architecture Business change architecture management C. G. Information Implementation Requirements systems management governance architectures F. D. Migration Technology planning architecture E. Opportunities and solutions Chapter 11 Systems of Systems 46" }, { "page_index": 389, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_047.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_047.png", "page_index": 389, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:54+07:00" }, "raw_text": "Architectural model management Software Engineering Initial model development takes a long time and involves extensive negotiations between system stakeholders. This slows the development of the overall system. It is time-consuming and expensive to maintain model consistency as changes are made to the organization and the constituent systems in a SoS. Chapter 11 Systems of Systems 47" }, { "page_index": 390, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_048.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_048.png", "page_index": 390, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:29:58+07:00" }, "raw_text": "Architectural patterns for SoS Software Engineering An architectural pattern is a stylized architecture that can be recognized across a range of different systems. Architectural patterns are a useful way of stimulating discussions about the most appropriate architecture for a system and for documenting and explaining the architectures usedl Chapter 11 Systems of Systems 48" }, { "page_index": 391, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_049.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_049.png", "page_index": 391, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:07+07:00" }, "raw_text": "Systems as data feeds Software Engineering There is a principal system that requires data of different types. This data is available from other systems and the principal system queries these systems to get the data required. Generally, the systems that provide data do not interact with each other. This pattern is often observed in organizational or federated systems where some governance mechanisms are in place Chapter 11 Systems of Systems 49" }, { "page_index": 392, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_050.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_050.png", "page_index": 392, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:11+07:00" }, "raw_text": "Systems as data feeds Software Engineering Data feed 3 Principal Data feed 2 Data feed 4 system Data feed 1 Chapter 11 Systems of Systems 50" }, { "page_index": 393, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_051.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_051.png", "page_index": 393, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:19+07:00" }, "raw_text": "Systems as data feeds Software Engineering The 'systems as data feeds' architecture is an appropriate architecture to use when it is possible to identify entities in a unique way and create relatively simple queries about these entities. A variant of the 'systems as data feeds' architecture arises when there are a number of systems involved which provide similar data but which are not identical. The architecture has to include an intermediate layer to translate the general query from the principal system into the specific query required by the individual information system. Chapter 11 Systems of Systems 51" }, { "page_index": 394, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_052.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_052.png", "page_index": 394, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:26+07:00" }, "raw_text": "Systems as data feeds with unifying interface Software Engineering Principal Data feed 2 Data feed 3 system Data feed 1 Data feed 1(a) Data feed 1(b) Data feed 1(c) Chapter 11 Systems of Systems 52" }, { "page_index": 395, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_053.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_053.png", "page_index": 395, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:34+07:00" }, "raw_text": "Systems in a container Software Engineering Systems in a container are systems of systems where one of the systems acts as a virtual container and provides a set of common services such as an authentication and a storage service. Conceptually, other systems are then placed into this container to make their functionality accessible to system users. You don't place systems into a real container to implement these systems of systems. Rather, for each approved system, there is a separate interface that allows it to be integrated with the common services. Chapter 11 Systems of Systems 53" }, { "page_index": 396, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_054.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_054.png", "page_index": 396, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:39+07:00" }, "raw_text": "Container systems Software Engineering Included systems s1 s2 s3 s4 s5 s6 Common service 3 Common service 2 Common service 1 Container system Chapter 11 Systems of Systems 54" }, { "page_index": 397, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_055.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_055.png", "page_index": 397, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:46+07:00" }, "raw_text": "ILearn container: common services Software Engineering An authentication service that provides a single sign-in to all approved systems. Users do not have to maintain separate credentials for these. A storage service for user data. This can be seamlessly transferred to and from approved systems. A configuration service that is used to include or remove systems from the container. Chapter 11 Systems of Systems 55" }, { "page_index": 398, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_056.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_056.png", "page_index": 398, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:51+07:00" }, "raw_text": "iLearn as a container Software Engineering The Digital Learning Environment Authentication Storage Configuration Science YouTube External interaction encyclopedia Interfaces Physics MS Office Lab data Moodle simulator 365 analyzer Chapter 11 Systems of Systems 56" }, { "page_index": 399, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_057.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_057.png", "page_index": 399, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:30:58+07:00" }, "raw_text": "Container architecture problems Software Engineering A separate interface must be developed for each approved system so that common services can be used with these systems. This means that only a relatively small number of approved systems can be supported. The owners of the container system have no influence on the functionality and behaviour of the included systems. Systems may stop working or may be withdrawn at any time Chapter 11 Systems of Systems 57" }, { "page_index": 400, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_058.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_058.png", "page_index": 400, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:31:06+07:00" }, "raw_text": "Trading systems Software Engineering Trading systems are systems of systems where there is no single principal system but processing may take place in any of the constituent systems The systems involved trade information amongst themselves. There may be one-to-one or one-to-many interactions between these systems. Each system publishes its own interface but there may not be any interface standards that are followed by all systems. Chapter 11 Systems of Systems 58" }, { "page_index": 401, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_059.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_059.png", "page_index": 401, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:31:14+07:00" }, "raw_text": "Trading systems Software Engineering Trading Trading system 1 system 2 A A Trading Trading system 3 system 4 Chapter 11 Systems of Systems 59" }, { "page_index": 402, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_060.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_060.png", "page_index": 402, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:31:20+07:00" }, "raw_text": "Trading SoS Software Engineering Trading systems may be developed for any type of marketplace with the information exchanged being information about the goods being traded and their prices. While trading systems are systems in their own right and could conceivably be used for individual trading, they are most useful in an automated trading context where the systems negotiate directly with each other. The major problem with this type of system is that there is no governance mechanism so any of the systems involved may change at any time Chapter 11 Systems of Systems 60" }, { "page_index": 403, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_061.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_061.png", "page_index": 403, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:31:29+07:00" }, "raw_text": "Key points Software Engineering Systems of systems are systems where two or more of the constituent systems are independently managed and governed. There are three types of complexity that are important for systems of systems - technical complexity, managerial complexity and governance complexity System governance can be used as the basis for a classification scheme for SoS. This leads to three classes of SoS namely organizational systems federated systems and system coalitions. Chapter 11 Systems of Systems 61" }, { "page_index": 404, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_062.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_062.png", "page_index": 404, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:31:39+07:00" }, "raw_text": "Key points Software Engineering Reductionism as an engineering method breaks down because of the inherent complexity of systems of systems Reductionism assumes clear system boundaries rational decision making and well-defined problems None of these are true for systems of systems. The key stages of the SoS development process are conceptual design, system selection, architectural design, interface development and integration and deployment. Governance and management policies must be designed in parallel with these activities. Chapter 11 Systems of Systems 62" }, { "page_index": 405, "chapter_num": 7, "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_063.png", "metadata": { "doc_type": "slide", "course_id": "CO3065", "source_file": "/workspace/data/converted/CO3065_Advanced_Software_Engineering/Chapter_7/slide_063.png", "page_index": 405, "language": "en", "ocr_engine": "PaddleOCR 3.2", "extractor_version": "1.0.0", "timestamp": "2025-10-31T23:31:44+07:00" }, "raw_text": "Key points Software Engineering Architectural patterns for systems of systems are a means of describing and discussing typical architectures for SoS Important patterns are systems as data feeds, systems in a container and trading systems. Chapter 11 Systems of Systems 63" } ] }