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https://en.wikipedia.org/wiki/Canvas%20fingerprinting | Canvas fingerprinting is one of a number of browser fingerprinting techniques for tracking online users that allow websites to identify and track visitors using the HTML5 canvas element instead of browser cookies or other similar means. The technique received wide media coverage in 2014 after researchers from Princeton University and KU Leuven University described it in their paper The Web never forgets.
Description
Canvas fingerprinting works by exploiting the HTML5 canvas element. As described by Acar et al. in:
Variations in which the graphics processing unit (GPU), or the graphics driver, is installed may cause the fingerprint variation. The fingerprint can be stored and shared with advertising partners to identify users when they visit affiliated websites. A profile can be created from the user's browsing activity, allowing advertisers to target advertise to the user's inferred demographics and preferences.
By January 2022, the concept was extended to fingerprinting performance characteristics of the graphics hardware, called by the researchers.
Uniqueness
Since the fingerprint is primarily based on the browser, operating system, and installed graphics hardware, it does not uniquely identify users. In a small-scale study with 294 participants from Amazon's Mechanical Turk, an experimental entropy of 5.7 bits was observed. The authors of the study suggest more entropy could likely be observed in the wild and with more patterns used in the fingerprint. While not sufficient to identify individual users by itself, this fingerprint could be combined with other entropy sources to provide a unique identifier. It is claimed that because the technique is effectively fingerprinting the GPU, the entropy is "orthogonal" to the entropy of previous browser fingerprint techniques such as screen resolution and browser JavaScript capabilities.
Much more unique identification becomes possible with , published in 2022, which was shown to boost tracking duration of individu |
https://en.wikipedia.org/wiki/2C2P | 2C2P is a financial services company headquartered in Singapore. The company primarily provides payment gateway services to businesses.
Overview
Businesses using 2C2P's platform include Lazada, Thai Airways International, and Lenovo.
History
2C2P was founded in Bangkok, Thailand in 2003 by Myanmar-born computer programmer Aung Kyaw Moe. In 2007, the company moved its headquarters to Singapore.
In 2009, 2C2P first secured a seed investment. 2C2P has since received financial backing from venture capitalists Amun Capital, GMO Venture Partners and Digital Media Partners.
In 2012, 2C2P launched an alternative payment method called 123, a local-currency alternative payment channel for non-credit-card payment processing.
In the fiscal year of 2014, the company processed over US$2.2 billion in transactions. Also in 2014, 2C2P partnered with Mastercard to launch easyBills, a platform that enables cardholders to pay utilities, mobile, and other bills via smartphone or the web.
In 2015, 2C2P completed the migration of its services to Amazon Web Services (AWS) and became the first online payment provider offering online credit card installments in Thailand.
In 2018, the company partnered with five major corporations to launch the first QR code payment gateway in Thailand.
In early 2020, 2C2P announced the launch of its investment arm, 2C2P.VC. In late 2020, the company refreshed its branding and website to create a more international and accessible look and feel.
In 2022, the company was named a participant in the Bank of Thailand's retail central bank digital currency (CBDC) pilot testing program.
In April 2022, 2C2P entered a strategic partnership with Chinese financial and payment company Ant Group, with the latter taking on a majority stake and linking Ant's Alipay+ payment service with 2C2P's existing payment gateway platform.
Products and services
2C2P provides payment acceptance, payouts, issuing, digital goods aggregation and reselling services.
The company |
https://en.wikipedia.org/wiki/Satellite%20delay | Satellite delay is the noticeable latency due to the limited speed of light, when sending data to and from satellites, especially distant geosynchronous satellites. Bouncing a signal off a geosynchronous satellite takes about a quarter of a second, which is enough to be noticeable, but relaying data between two or three such satellites increases the delay.
See also
Geosynchronous satellite
References
Engineering concepts |
https://en.wikipedia.org/wiki/Hypertext%20Application%20Language | Hypertext Application Language (HAL) is a convention for defining hypermedia such as links to external resources within JSON or XML code. It is documented in an Internet Draft (a "work in progress"), with the latest version 11 published the 10th of October 2023. The standard was initially proposed in June 2012 specifically for use with JSON and has since become available in two variations, JSON and XML. The two associated MIME types are media type: application/hal+xml and media type: application/hal+json.
HAL was created to be simple to use and easily applicable across different domains by avoiding the need to impose any requirements on how the project be structured. Maintaining this minimal impact approach, HAL has enabled developers to create general-purpose libraries which can be easily incorporated on any API that uses HAL.
APIs that adopt HAL simplify the use of open source libraries and make it possible to interact with the API using JSON or XML. The alternative would be having to develop a proprietary format which in turn forces developers to learn how to use yet another foreign format.
Convention
HAL is structured in such a way as to represent elements based on two concepts: Resources and Links. Resources consist of URI links, embedded resources, your standard data (be it JSON or XML), and non URI links. Links have a target URI, as well as the name of the link (referred to as 'rel'), as well as optional properties designed to be mindful of deprecation and content negotiation.
Example
General Resource
{
"_links": {
"self": {
"href": "http://example.com/api/book/hal-cookbook"
}
},
"id": "hal-cookbook",
"name": "HAL Cookbook"
}
Embedded resource
{
"_links": {
"self": {
"href": "http://example.com/api/book/hal-cookbook"
}
},
"_embedded": {
"author": {
"_links": {
"self": {
"href": "http://example.com/api/author/shahadat"
}
},
"id": "shahadat",
"name": "Sha |
https://en.wikipedia.org/wiki/Ftrace | ftrace (Function Tracer) is a tracing framework for the Linux kernel. Although its original name, Function Tracer, came from ftrace's ability to record information related to various function calls performed while the kernel is running, ftrace's tracing capabilities cover a much broader range of kernel's internal operations.
Details
With its various tracer plugins, ftrace can be targeted at different static tracepoints, such as scheduling events, interrupts, memory-mapped I/O, CPU power state transitions, and operations related to file systems and virtualization. Also, dynamic tracking of kernel function calls is available, optionally restrictable to a subset of functions by using globs, and with the possibility to generate call graphs and provide stack usage reports. At the same time, ftrace can be used to measure various latencies within the Linux kernel, such as for how long interrupts or preemption are disabled.
An ftrace-enabled Linux kernel is built by enabling the kernel configuration option. The entire runtime interaction with ftrace is performed through readable and writable virtual files contained in a specifically mounted debugfs file system; as a result, ftrace requires no specialized userspace utilities to operate. However, there are additional userspace utilities that provide more advanced features for data recording, analysis and visualization; examples of such utilities are trace-cmd and KernelShark.
Internally, ftrace relies on the gcc's profiling mechanism to prepend machine instructions to the compiled versions of all source-level kernel functions, which redirect the execution of functions to the ftrace's trampolines and tracer plugins that perform the actual tracing. These "entry point" instructions created by gcc are altered by ftrace when the kernel is booted, and varied later at runtime by ftrace between NOPs and actual jumps to the tracing trampolines, depending on the tracing types and options configured at runtime.
ftrace is deve |
https://en.wikipedia.org/wiki/Format-transforming%20encryption | In cryptography, format-transforming encryption (FTE) refers to encryption where the format of the input plaintext and output ciphertext are configurable. Descriptions of formats can vary, but are typically compact set descriptors, such as a regular expression.
Format-transforming encryption is closely related to, and a generalization of, format-preserving encryption.
Applications of FTE
Restricted fields or formats
Similar to format-preserving encryption, FTE can be used to control the format of ciphertexts. The canonical example is a credit card number, such as 1234567812345670 (16 bytes long, digits only).
However, FTE does not enforce that the input format must be the same as the output format.
Censorship circumvention
FTE is used by the Tor Project to circumvent deep packet inspection by pretending to be some other protocols. The implementation is ; it was written by the authors who came up with the FTE concept.
References
Cryptography
Content-control software
Internet censorship |
https://en.wikipedia.org/wiki/Comparison%20of%20cryptography%20libraries | The tables below compare cryptography libraries that deal with cryptography algorithms and have API function calls to each of the supported features.
Cryptography libraries
FIPS 140
This table denotes, if a cryptography library provides the technical requisites for FIPS 140, and the status of their FIPS 140 certification (according to NIST's CMVP search, modules in process list and implementation under test list).
Key operations
Key operations include key generation algorithms, key exchange agreements and public key cryptography standards.
Public key algorithms
Elliptic-curve cryptography (ECC) support
Public key cryptography standards
Hash functions
Comparison of supported cryptographic hash functions. Here hash functions are defined as taking an arbitrary length message and producing a fixed size output that is virtually impossible to use for recreating the original message.
MAC algorithms
Comparison of implementations of message authentication code (MAC) algorithms. A MAC is a short piece of information used to authenticate a message—in other words, to confirm that the message came from the stated sender (its authenticity) and has not been changed in transit (its integrity).
Block ciphers
Table compares implementations of block ciphers. Block ciphers are defined as being deterministic and operating on a set number of bits (termed a block) using a symmetric key.
Each block cipher can be broken up into the possible key sizes and block cipher modes it can be run with.
Block cipher algorithms
Cipher modes
Stream ciphers
The table below shows the support of various stream ciphers. Stream ciphers are defined as using plain text digits that are combined with a pseudorandom cipher digit stream. Stream ciphers are typically faster than block ciphers and may have lower hardware complexity, but may be more susceptible to attacks.
Hardware-assisted support
These tables compare the ability to utilize hardware enhanced cryptography. By using the assistan |
https://en.wikipedia.org/wiki/Kanopy | Kanopy is an on-demand streaming video platform for public and academic libraries that offers films, TV shows and documentaries. The service is free for users, but content owners and content creators are paid on a pay-per-view model by the institution.
The company was founded in Scarborough, Western Australia on December 25, 2008, moving its headquarters to San Francisco, California a few years later. On June 9, 2021, it was announced that OverDrive had reached a deal to acquire Kanopy. The acquisition was later completed on July 15, 2021. Kanopy's subdivision, Kanopy Kids, includes children's programming; all Kanopy member accounts have access to Kanopy Kids.
History
Kanopy was founded on December 25, 2008, at Scarborough, Western Australia, by Olivia Humphrey, an Australian entrepreneur, as an educational tool for colleges and universities. Until 2010, the company functioned only as a DVD distributor, moving into streaming in that year. After attaining considerable success in Australia, New Zealand, Hong Kong and Singapore, it expanded into the UK and US, and soon afterwards moved its headquarters to San Francisco, with Humphrey remaining as CEO.
In October 2019, Kevin Sayar succeeded Humphrey as CEO. On June 9, 2021, OverDrive announced that it had reached a deal to acquire Kanopy. The acquisition was later completed on July 15, 2021.
Services
Kanopy provides each participating public library, college and university with a dedicated and customizable website through which members can stream films. The service includes features such as captions, transcripts, clip creation, and playlist creation that allow users to share videos.
Business model
Public library patrons, college and university students and faculty are able to watch Kanopy free-of-charge with their institution's library card. Institutions pay for the films their students and faculty watch on a per-view basis. This model used by libraries is referred to as "patron-driven acquisition" where each view |
https://en.wikipedia.org/wiki/IPage | iPage () is a web hosting company.
History
iPage was initially founded in 1998 as a full web service provider, but the company re-launched operations as a web hosting provider in 2009. It's currently owned by Endurance International Group. In 2023 it merged with web.com. iPage hosts currently more than one million websites in its two large data centers. However, iPage faces criticism for its speed, uptime, and customer support. Be advised of random billing. Website not available as of 4/7/2022.
Features
iPage offers several types of hosting. Some of them are:
Shared hosting: That enables users to host unlimited domains for a monthly fee. Features offered by iPage are similar to other unlimited shared hosting services and include unlimited disk storage, data transfers, email addresses, FTP accounts, addon domain names, free SSL, and MySQL databases.
Virtual private servers determining the RAM, CPU, disk space and bandwidth specifications including cPanel.
Dedicated Servers
WordPress hosting: Which is only to host websites that use WordPress but with addon services such as expert support in WordPress.
References
Web hosting
Endurance International Group |
https://en.wikipedia.org/wiki/Tribe%20of%20Noise | Tribe of Noise BV is a social networking service catered to musicians.
History
Tribe of Noise was founded by Sandra Brandenburg and Hessel van Oorschot in 2008 with an objective was to create an open community where independent musicians could share their music legally with businesses and media professionals in return for exposure. It was one of 23 finalists in The Next Web PayPal X Startup Rally 2010.
Tribe of Noise has partnerships with companies including Getty Images,. On September 12, 2019, Tribe of Noise acquired Free Music Archive for an undisclosed amount.
References
External links
Dutch music websites
Dutch social networking websites |
https://en.wikipedia.org/wiki/Fully%20probabilistic%20design | Decision making (DM) can be seen as a purposeful choice of action sequences. It also covers control, a purposeful choice of input sequences. As a rule, it runs under randomness, uncertainty and incomplete knowledge. A range of prescriptive theories have been proposed how to make optimal decisions under these conditions. They optimise sequence of decision rules, mappings of the available knowledge on possible actions. This sequence is called strategy or policy. Among various theories, Bayesian DM is broadly accepted axiomatically based theory that solves the design of optimal decision strategy. It describes random, uncertain or incompletely known quantities as random variables, i.e. by their joint probability expressing belief in their possible values. The strategy that minimises expected loss (or equivalently maximises expected reward) expressing decision-maker's goals is then taken as the optimal strategy. While the probabilistic description of beliefs is uniquely and deductively driven by rules for joint probabilities, the composition and decomposition of the loss function have no such universally applicable formal machinery.
Fully probabilistic design (of decision strategies or control, FPD) removes the mentioned drawback and expresses also the DM goals of by the "ideal" probability, which assigns high (small) values to desired (undesired) behaviours of the closed DM loop formed by the influenced world part and by the used strategy. FPD has axiomatic basis and has Bayesian DM as its restricted subpart.
FPD has a range of theoretical consequences
,
and, importantly, has been successfully used to quite diverse application domains.
References
See also
Bayesian probability
Decision-making
Axiomatic system
Decision-making
& |
https://en.wikipedia.org/wiki/ACM%20Transactions%20on%20Software%20Engineering%20and%20Methodology | ACM Transactions on Software Engineering and Methodology is a quarterly peer-reviewed scientific journal covering software engineering published by the Association for Computing Machinery since 1992. The editor-in-chief is Mauro Pezzè (Università della Svizzera italiana and Schaffhausen Institute of Technology). According to the Journal Citation Reports, the journal has a 2021 impact factor of 4.4.
References
External links
Transactions on Software Engineering and Methodology
Computer science journals
Software engineering publications
Quarterly journals
Academic journals established in 1992
English-language journals |
https://en.wikipedia.org/wiki/Briar%20%28software%29 | Briar is an open-source software communication technology, intended to provide secure and resilient peer-to-peer communications with no centralized servers and minimal reliance on external infrastructure. Messages can be transmitted through Bluetooth, Wi-Fi, over the internet via Tor or removable storage, such as USB sticks. All communication is end-to-end encrypted. Relevant content is stored in encrypted form on participating devices. Long-term plans for the project include support for distributed applications such as crisis mapping and collaborative document editing.
The initial target audience for Briar includes "activists, journalists and civil society" with plans to make the system "simple enough to help anyone keep their data safe." As the ability to function in the absence of internet infrastructure may also make the project valuable to disaster response and aid organizations, the developers are working with the Open Humanitarian Initiative and Taarifa. Ultimately, the developers aim to create a system which is "as simple to use as WhatsApp, as secure as PGP, and that keeps working if somebody breaks the Internet." It is possible for an Android device to download Briar from another Android device which already has Briar installed.
Briar's source code is published as free software and the Android app is distributed under the terms of the GNU GPL-3.0-or-later license, while the desktop version is released under the Affero General Public License. Briar Desktop runs on Windows, macOS and Linux. Briar Desktop will also run on true Linux (non-Android) mobile phones, running operating systems like Manjaro, PureOS and postmarketOS, once it has been adapted to mobile form-factors.
Briar was audited by Cure53 and spoken highly of in a report delivered 20 March 2017, and was recommended to be given a second audit after development completes. As of 2018 the project received $361,100 of funding from the Open Technology Fund.
Briar uses the Bramble protocol suite (Bra |
https://en.wikipedia.org/wiki/Motovlog | A motovlog is a type of video log recorded by a person while riding a motorcycle or any motorized vehicle. The word is a neologism and portmanteau derived from "motorcycle", "video" and "log".
A rider who creates video blogs known as a motorcycle blogger, and the action of making motovlogs is called motovlogging. Most motovloggers upload their videos on YouTube, and the network of motovloggers here is known as the motovloggers community.
YouTube
There are many channels on YouTube dedicated to motovlogging. Many motovloggers do not show their face or the license plate of their motorcycle in videos. The British motovlogger, BaronVonGrumble, stated in an interview that anonymity exists to make the videos more mysterious and exciting to watch.
Motovloggers have occasionally captured traffic accidents while riding with the camera running. There are also videos of motovloggers helping out randomly encountered people.
Sometimes motovloggers encounters the road rage and the vlog lands into a digital proof which could be used as an evidence.
References
Video blogs
Film and video technology
Web syndication |
https://en.wikipedia.org/wiki/Data%20exploration | Data exploration is an approach similar to initial data analysis, whereby a data analyst uses visual exploration to understand what is in a dataset and the characteristics of the data, rather than through traditional data management systems. These characteristics can include size or amount of data, completeness of the data, correctness of the data, possible relationships amongst data elements or files/tables in the data.
Data exploration is typically conducted using a combination of automated and manual activities. Automated activities can include data profiling or data visualization or tabular reports to give the analyst an initial view into the data and an understanding of key characteristics.
This is often followed by manual drill-down or filtering of the data to identify anomalies or patterns identified through the automated actions. Data exploration can also require manual scripting and queries into the data (e.g. using languages such as SQL or R) or using spreadsheets or similar tools to view the raw data.
All of these activities are aimed at creating a mental model and understanding of the data in the mind of the analyst, and defining basic metadata (statistics, structure, relationships) for the data set that can be used in further analysis.
Once this initial understanding of the data is had, the data can be pruned or refined by removing unusable parts of the data (data cleansing), correcting poorly formatted elements and defining relevant relationships across datasets. This process is also known as determining data quality.
Data exploration can also refer to the ad hoc querying or visualization of data to identify potential relationships or insights that may be hidden in the data and does not require to formulate assumptions beforehand.
Traditionally, this had been a key area of focus for statisticians, with John Tukey being a key evangelist in the field. Today, data exploration is more widespread and is the focus of data analysts and data scientists; |
https://en.wikipedia.org/wiki/Tawkers | Tawkers is a Saas application, which allows publishers to create and distribute branded text message conversations live or after the fact. The application is created for various devices, but was originally launched as an iPhone app and has become a set of content tools for brand marketers and publishers. Tawkers is owned and managed by Tawkers Inc, which was founded in 2011.
The company launched a beta of Tawkers as a web application in 2013, before releasing the official version in March 2014. Gizmodo Brazil ranked Tawkers in their list of top iPhone Apps for that particular month.
In 2016, Tawkers began work on a SaaS product, creating an enterprise solution for brands, agencies and publishers to create and manage public messaging content between influencers. The content is then embedded across the client's media. This new offering followed a partnership with NBCUniversal and 360i in which the companies utilized the technology to create content for their owned, earned and paid media channels, as well as within mobile applications. The first campaign was with the Bravo TV show Odd Mom Out.
Background
Blake Ian is the current CEO and co-founded the company in 2011 in New York City after having the idea of sharing text conversations while he was chatting with a friend about a film over instant messaging. In late 2011, after developing the idea, the company received $360,000 in seed funding.
Following the development of a beta in 2013, Ian stated to TechCrunch that he believed that celebrities would use the Tawkers platform as a way to engage with fans and also engage conversation on given subjects.
The app did just that in the early stages of the beta, with Lee Camp, Ron "Bumblefoot" Thal, Colin Quinn, singer Eleanor Goldfield, Deepak Chopra, and also Howard Rheingold using the app during the early parts of its existence.
In March 2014, Gizmodo Brazil ranked Tawkers in their list of top Apps.
Mechanics
According to their website, the application aims to bridge |
https://en.wikipedia.org/wiki/Databending | Databending (or data bending) is the process of manipulating a media file of a certain format, using software designed to edit files of another format. Distortions in the medium typically occur as a result, and the process is frequently employed in glitch art.
Process and techniques
The term databending is derived from circuit bending, in which objects such as children's toys, effects pedals and electronic keyboards are deliberately short circuited by bending the circuit board to produce erratic and spontaneous sounds. Like circuit bending, databending involves the (often unpredictable) alteration of its target's behavior. Databending achieves this alteration by manipulating the information within a media file of a certain format, using software designed to edit files of a different format; distortions in the medium typically occur as a result.
Many techniques exist, including the use of hex editors to manipulate certain components of a compression algorithm, to comparatively simple methods. Michael Betancourt has posed a short set of instructions, included in the Signal Culture Cookbook, that involves the direct manipulation of the digital file using a hexadecimal editing program. One such method involves the addition of audio effects through audio editing software to distort raw data interpretations of image files. Some effects produce optical analogues: adding an echo filter duplicated elements of a photo, and inversion contributed to the flipping over of an image. The similarities result from the waveforms corresponding with the layers of pixels in a linear fashion, ordered from top to bottom. Another method, dubbed "the WordPad effect", uses the program WordPad to manipulate images through converting the raw data to the Rich Text Format.
Categorization
According to the artist Benjamin Berg, different techniques of the process can be grouped into three categories:
Incorrect editing: Files of a certain format are manipulated using software designed to edit |
https://en.wikipedia.org/wiki/Pica8 | Pica8, Inc. is a computer networking company headquartered in Palo Alto, California, United States. Pica8 is a vendor of open-standards-based operating systems on white box network switches delivering software-defined networking (SDN) solutions for datacenter and cloud computing environments and traditional L2/L3 solutions for large enterprise customers. The company's products include a Linux-based L2/L3 and OpenFlow-supporting network operating system, PicOS, which is shipped as standalone software that can be loaded onto a range of 1/10/40/100 Gigabit Ethernet switches based on commoditized ("white box") switches purchased from original design manufacturers (ODMs).
The company's approach is to combine commodity network hardware (from manufacturers like Accton, Foxconn, Quanta) with Debian Linux, L2/L3 protocol stacks, a full enterprise feature set, OpenFlow controller and Open vSwitch (OVS) to create both a more "democratic" SDN solutions with competitive price compared to conventional embedded switches as well as more flexible and scalable disaggregated enterprise white box networking solutions.
History
The company was founded in 2009. It launched a family of OpenFlow-enabled Ethernet switches in August 2009 and has been selling products ever since.
In 2010, Pica8 was selling 48-port gigabit Ethernet and 10-gigabit Ethernet switches at half the price of comparable products of Force10 and Arista Networks. It achieved such result through combining open source software with merchant ASICs (from companies like Broadcom, Marvell, and Intel/Fulcrum) on switches from "white-box vendors".
In July 2011, Pica8 added support for the open source "Indigo" OpenFlow stack from Big Switch Networks to its switches as an alternative stack. In November 2011 it embedded Open vSwitch (OVS), developed by Nicira, into its operation system PicOS to enable more sophisticated network management from inside the switch.
In October 2012 Pica8 raised $6.6m in Series A funding from Vanta |
https://en.wikipedia.org/wiki/SESI%20Mathematics | SESI Mathematics is a project developed by FIRJAN System with the aim of improving the teaching of math for high school students. The program consists of a series of initiatives, from the organization of training courses for teachers and distribution of educational kits, to the providing of physical spaces for students of SESI Rio and SENAI Rio network, as well as for those from selected state schools. Although the project has the pretension of being expanded to other Brazilian states, nowadays it only operates in the states of Rio de Janeiro and Bahia.
History
SESI Mathematics was launched in 2012 by SESI Rio. The program counted on an initial investment of R$ 10 million and was created based on the Lei de Diretrizes e Bases da Educação Nacional (read "Law of Guidelines and Bases of National Education"), motivated by the poor performance of Brazil in national and international reviews, as well as in researches that indicated a lack of skilled people to work in areas related to the exact sciences, which require mastery of mathematics.
In 2013, an agreement was signed between SESI Bahia and the Government of Bahia State to extend the project to the schools of the state of Bahia. In the same year, the project won the Idea Brasil award in the "Design Strategy" category.
Methodology
The project's initiatives make use of online interactive technologies such as educational games as a way to encourage the teaching of students.
The games are developed by the English company Mangahigh.
SESI Mathematics House
In partnership with the Instituto Nacional de Matemática Pura e Aplicada (read "National Institute for Pure and Applied Mathematics"), one of the initiatives of the project is the construction of a public space dedicated to temporary and permanent exhibitions of themes related to mathematics, among other activities. The space will be located at Barra da Tijuca (Rio de Janeiro, Brasil) and is scheduled to open in 2015.
Notes
References
External links
SESI Mat |
https://en.wikipedia.org/wiki/Hessian%20Bibliography | The Hessian Bibliography () is a German regional bibliography. Its aim is to completely capture all the literature connected with the geography, history and culture of the German federal state of Hesse from the year 1974. It is based on the holdings of the copyright libraries at Kassel, Fulda, Frankfurt, Wiesbaden and Darmstadt.
By 2000 a total of 24 indexed year books had appeared in print; since then it has only been available in electronic form as a freely accessible database of the Hessian library information system (HEBIS). The titles are recorded in accordance with the Rules for Alphabetic Cataloguing and accessed using a comprehensive system of about 1,200 system sites and keywords. About 6,500 bibliographic records are added per year.
The Hessian bibliography is part of the Virtual German National Bibliography, which has its own web portal.
For the period before 1974, the "Literature on the History and Historic Geograph and Culture of Hesse" is used. This consists of seven printed volumes by Karl Ernst Demandt (covering the period to 1964) and by Winfried Leist and Wolfgang Podehl (covering the period 1965-1976). Currently, the volumes of Podehl and Leist are gradually being added retrospectively to the database.
References
Literature
Brigitte Störch: Landesbibliographische Berichterstattung in Hessen. In: Ludger Syré (ed.): Die Regionalbibliographie im digitalen Zeitalter. Frankfurt a.M. 2006, pp. 257–266. Full text (pdf; 154 kB)
External links
Hessian Bibliography
Hesse, State Bibliography
Online databases
Geography of Hesse |
https://en.wikipedia.org/wiki/Regulatory%20B%20cell | Regulatory B cells (Bregs or Breg cells) represent a small population of B cells that participates in immunomodulation and in the suppression of immune responses. The population of Bregs can be further separated into different human or murine subsets such as B10 cells, marginal zone B cells, Br1 cells, GrB+B cells, CD9+ B cells, and even some plasmablasts or plasma cells. Bregs regulate the immune system by different mechanisms. One of the main mechanisms is the production of anti-inflammatory cytokines such as interleukin 10 (IL-10), IL-35, or transforming growth factor beta (TGF-β). Another known mechanism is the production of cytotoxic Granzyme B. Bregs also express various inhibitory surface markers such as programmed death-ligand 1 (PD-L1), CD39, CD73, and aryl hydrocarbon receptor. The regulatory effects of Bregs were described in various models of inflammation, autoimmune diseases, transplantation reactions, and in anti-tumor immunity.
History
In the 1970s it was noticed that Bregs could suppress immune reaction independently of antibody production. In 1996 Janeway's group observed an immunomodulation of experimental autoimmune encephalomyelitis (EAE) by B cells. Similar results were shown in a model of chronic colitis one year later. Then a role of Bregs was found in many mouse models of autoimmune diseases as rheumatoid arthritis or systemic lupus erythematosus (SLE).
Development and populations
Bregs can develop from different subsets of B cells such as immature and mature B cells or plasmablasts. Whether Breg cells uniquely derive from a specific progenitor or originate within conventional B cell subsets is still an open question. Unfortunately, Breg cells are more difficult to define than regulatory T cells (Tregs) since they lack a lineage marker analogous to the Treg cell marker - FOXP3. Bregs share many markers with various B cell subsets due to their origin. Human and murine Bregs can be further separated into many subsets due to their different m |
https://en.wikipedia.org/wiki/Link-ZA | Link-ZA (also "Link ZA" or "LinkZA") is a tactical data link system used by the South African National Defence Force. It is the data communication component of the "Combat Net Interoperability Standard" (CNIS). Development began in the early 1990s when South Africa acquired a wide variety of high technology defence equipment such as Saab JAS 39 Gripen fighter jets, BAE Hawk lead-in fighter trainers, Valour-class frigates and other weapons systems. Because South Africa was not able to acquire the NATO standard Link-16 system an indigenous system was developed.
Features
Link-ZA is a multi-platform secure network protocol operating over HF, VHF or UHF radio or satellite link. It uses TDMA and CSMA to establish links and share data with up to 31 active nodes and an unlimited number of passive nodes. Static or dynamic routing tables are supported. Link-ZA node controllers have store and forward capability to transfer data between different radio nets. A node controller can access multiple radios and automatically select the most appropriate link.
References
Further sources
Military communications
Network protocols
Military radio systems
Post–Cold War military equipment of South Africa |
https://en.wikipedia.org/wiki/List%20of%20medical%20textbooks | This is a list of medical textbooks, manuscripts, and reference works.
Pre-modern texts
Ancient Egypt
Ramesseum medical papyri (c. 1800 BCE)
Kahun Gynaecological Papyrus (c. 1800 BCE)
London Medical Papyrus (c. 1600 BCE)
Ebers Papyrus (c. 1550 BCE)
Edwin Smith Papyrus (c. 1500 BCE) - Earliest mention of the brain; the pulse; the role of the heart in circulating blood, but not complete circulation. It is the world's oldest surgical textbook, containing descriptions of the zygomatic bone, dura mater, cerebrospinal fluid, and nasal cavity.
Brugsch Papyrus (c. 1200 BCE)
Ancient Greece
Hippocratic Corpus (c. 400 BCE to 200 CE) - Contains many important medical treatises including the Hippocratic Oath. Compared with the Egyptian papyri, the Hippocratic writings exhibit an improved understanding of brain structure and function. It correctly attributed the primary control of the body's function to the brain.
Galenic corpus (c. 200 BCE)
De Materia Medica (Dioscorides) (c. 50 CE)
Medical Compendium in Seven Books (c. 600 CE)
Ancient China
Huangdi Neijing (c. 300 BCE) - Most authoritative Chinese source on medical matters for over two millennia. It contributed to the Chinese understanding of anatomy, and it continues to be used as an influential reference work for practitioners of traditional Chinese medicine. The book contains many guidelines and recommendations for the prevention of chronic diseases and micronutrient deficiencies such as beriberi, xerophthalmia, and goitre.
Wushi'er Bingfang (c. 200 BCE)
Shennong Ben Cao Jing (c. 200 CE)
Shanghan Lun (c. 220 CE)
Liu Juanzi Guiyi Fang (C. 499 CE)
Compendium of Materia Medica (c. 1578 CE)
Ancient India
Kashyapa Samhita (6th century BCE)
Sushruta Samhita (c. 300 BCE) - Early description of cataract surgery. The Sushruta Samhita emphasizes the importance of anatomical structure and function, and it contains the earliest written description of the pedicled flaps. It was translated into Arabic during |
https://en.wikipedia.org/wiki/NESiCAxLive | is a digital distribution system for arcade video games made by Taito. It is similar to the SEGA ALL.Net game distribution system. Taito uses NESiCAxLive to distribute not only its own games, but also allows other companies to use it as a publication platform. On its introduction SNK, Cave, and Arc System Works had agreed to distribute games on NESiCAxLive. Currently, 8 games are operated as alone running titles and 29 titles as downloadable titles on candy cabinets.
History
The system was first revealed in September 2010 at the 48th Amusement Machine Show in Chiba, Japan, as the Taito Vewlix NESiCA arcade cabinet, and was launched on 9 December 2010. The first game to be released for the system was Arc System Works' BlazBlue: Continuum Shift II. Taito introduced the NESiCAxLive 2 system in June 2017.
System
The NESiCAxLive system consists of an arcade system board combined with a dedicated router to access and download games. The system currently works on the Taito Type X2, Taito Type X Zero, Taito Type X3, and Taito Type X4 arcade boards. The connected machines access the Taito NESYS online network to allow arcade operators to download games from Taito's servers directly to the arcade cabinet; previously arcade operators had to purchase new game boards (as well as dispose of old ones) to run a new game. Games can also be downloaded to a local server to allow quicker distribution to machines, as well as allow rapid swapping in and out of games according to player demand. Taito allows arcade operators to download games free, as part of a revenue sharing system, with income split with Taito and the game developer. The original NESiCAxLive system was originally exclusively available in Japan, however there has been a gradual introduction to the US market.
Taito introduced the NESiCAxLive 2 platform in June 2017. The upgraded system allows player versus player competition between machines in different locations, as well having improved CPU and GPU performance.
NES |
https://en.wikipedia.org/wiki/NESYS | The Taito NESYS (Network Entry System) is an arcade game network communication system by Taito. It connects up arcade machines via a network, and allows players to participate in national rankings and online play, as well as allowing arcade operators to download updates for games. The Taito NESiCAxLive digital distribution system uses NESYS as its networking system.
The system uses the NESYS IC Card smart card to allow players to save game data at arcade machines; one example of this is Street Fighter IV. These cards will remain compatible with the machine even as the games it hosts change. The card itself can hold data for multiple different games at the same time. This is similar to the Konami e-AMUSEMENT system, and the smart card function of the SEGA ALL.Net system.
See also
Taito NESiCAxLive
References
External links
Taito arcade system boards
Taito
Online video game services |
https://en.wikipedia.org/wiki/Vincent%20average | In applied statistics, Vincentization was described by Ratcliff (1979), and is named after biologist S. B. Vincent (1912), who used something very similar to it for constructing learning curves at the beginning of the 1900s. It basically consists of averaging subjects' estimated or elicited quantile functions in order to define group quantiles from which can be constructed.
To cast it in its greatest generality, let represent arbitrary (empirical or theoretical) distribution functions and define their corresponding quantile functions by
The Vincent average of the 's is then computed as
where the non-negative numbers have a sum of .
References
Applied statistics |
https://en.wikipedia.org/wiki/Equivalent%20definitions%20of%20mathematical%20structures | In mathematics, equivalent definitions are used in two somewhat different ways. First, within a particular mathematical theory (for example, Euclidean geometry), a notion (for example, ellipse or minimal surface) may have more than one definition. These definitions are equivalent in the context of a given mathematical structure (Euclidean space, in this case). Second, a mathematical structure may have more than one definition (for example, topological space has at least seven definitions; ordered field has at least two definitions).
In the former case, equivalence of two definitions means that a mathematical object (for example, geometric body) satisfies one definition if and only if it satisfies the other definition.
In the latter case, the meaning of equivalence (between two definitions of a structure) is more complicated, since a structure is more abstract than an object. Many different objects may implement the same structure.
Isomorphic implementations
Natural numbers may be implemented as 0 = , 1 = = , 2 = = , 3 = = and so on; or alternatively as 0 = , 1 = =, 2 = = and so on. These are two different but isomorphic implementations of natural numbers in set theory.
They are isomorphic as models of Peano axioms, that is, triples (N,0,S) where N is a set, 0 an element of N, and S (called the successor function) a map of N to itself (satisfying appropriate conditions). In the first implementation S(n) = n ∪ ; in the second implementation S(n) = . As emphasized in Benacerraf's identification problem, the two implementations differ in their answer to the question whether 0 ∈ 2; however, this is not a legitimate question about natural numbers (since the relation ∈ is not stipulated by the relevant signature(s), see the next section). Similarly, different but isomorphic implementations are used for complex numbers.
Deduced structures and cryptomorphisms
The successor function S on natural numbers leads to arithmetic operations, addition and multiplication, |
https://en.wikipedia.org/wiki/Research%20Office%20of%20the%20Reich%20Air%20Ministry | The Research Office of the Reich Air Ministry (German: RLM/Forschungsamt (FA), English: "Research Bureau") was the signals intelligence and cryptanalytic agency of the German Nazi Party from 1933 to 1945. Run since its inception by Luftwaffe chief Hermann Göring, the Research Bureau was a Nazi Party institution rather than an official Wehrmacht-run military signals intelligence and cryptographic agency (headed up by the German High Command's OKW/Chi).
Described as "the richest, most secret, the most Nazi, and the most influential" of all the German cryptoanalytic intelligence agencies, its existence was well known to French intelligence (Deuxième Bureau, Bureau Central de Renseignements et d'Action) via the efforts of the spy Hans-Thilo Schmidt but little known to other countries within the Allies.
The organization was described by the historian, Dr Wilhelm F. Flicke, a German veteran cipher officer, who was commissioned by General Erich Fellgiebel, to write a history of German cryptography and cryptanalysis during World War II in his book War secrets in the ether as:
calculated to give the government and the [Nazi] dominant party such far-reaching insight into the thoughts, feelings, and aspirations of the German people as had been known in all history. Compared with this plan, the informer methods of Metternich and the French Minister of Police, Fouché had been amateurish experiments.
Other names for the FA included Hermann Göring's Research Bureau and Hermann Göring cipher bureau. Its official full name in German was Forschungsamt des Reichsluftfahrt Ministerium, and in English the "Research Office of the Ministry of Aviation",(Luftwaffe)
Emergence
The office of the RLM/Forschungsamt emerged with the events of the Reichstag Fire Decree. With Adolf Hitler's seizure of power by the Enabling Act of 1933, all postal, telegraph and telephone democracy was suspended. The Reichstag Fire Decree Articles 114, 115, 117, 118, 123, 124 and 153 of the Constitution of the |
https://en.wikipedia.org/wiki/Seto%20Digital%20Tower | Seto Digital Tower is a 244.7 m (803 ft) tall digital broadcasting tower in Seto, Aichi, Japan. In 2011, the tower replaced the Nagoya TV Tower; the Nagoya TV Tower previously had the role of broadcasting in the Nagoya area. The tower is of a unique design not known to have been used elsewhere before. Six outer steel legs provide support and structural stability to a central lattice structure akin to those found in guyed lattice masts.
See also
Lattice tower
References
File:Seto Digital Tower.jpg - Wikimedia Commons
External links
Buildings and structures in Aichi Prefecture
Communication towers in Japan
Radio masts and towers
Towers completed in 2011
2011 establishments in Japan
Seto, Aichi |
https://en.wikipedia.org/wiki/Renewable%20Energy%20%28journal%29 | Renewable Energy is a monthly peer-reviewed scientific journal covering research on renewable energy, sustainable energy and the energy transition. It is published by Elsevier and the editor-in-chief is Soteris Kalogirou (Cyprus University of Technology). According to the Journal Citation Reports, the journal has a 2021 impact factor of 8.634. It was originally established as Solar & Wind Technology in 1984, acquiring its current name in 1991.
References
External links
Elsevier academic journals
Academic journals established in 1984
English-language journals
Energy and fuel journals
Monthly journals
Journal |
https://en.wikipedia.org/wiki/Dark%20silicon | In the electronics industry, dark silicon is the amount of circuitry of an integrated circuit that cannot be powered-on at the nominal operating voltage for a given thermal design power (TDP) constraint.
Dennard scaling would posit that as transistors get smaller, they become more efficient in proportion to the increase in number for a given area, but this scaling has broken down in recent years, meaning that increases in the efficiency of smaller transistors are not proportionate with the increase in their number. This discontinuation of scaling has led to sharp increases in power density that hamper powering-on all transistors simultaneously while keeping temperatures in a safe operating range.
As of 2011, researchers from different groups have projected that, at 8 nm technology nodes, the amount of dark silicon may reach up to 50–80% depending upon the processor architecture, cooling technology, and application workloads. Dark silicon may be unavoidable even in server workloads with abundance of inherent client request-level parallelism.
Challenges and opportunities
The emergence of dark silicon introduces several challenges for the architecture, electronic design automation (EDA), and hardware-software co-design communities. These include the question of how best to utilize the plethora of transistors (with potentially many dark ones) when designing and managing energy-efficient on-chip many-core processors under peak power and thermal constraints. Architects have initiated several efforts to leverage dark silicon in designing application-specific and accelerator-rich architectures.
Recently, researchers have explored how dark silicon exposes new challenges and opportunities for the EDA community. In particular, they have demonstrated thermal, reliability (soft error and aging), and process variation concerns for dark silicon many-core processors.
References
Electronic design |
https://en.wikipedia.org/wiki/Energy%20Policy%20%28journal%29 | Energy Policy is a monthly peer-reviewed academic journal covering research on energy policy and energy supply. It is published by Elsevier. According to the Journal Citation Reports, Energy Policy has a 2022 impact factor of 9.0.
References
External links
Elsevier academic journals
Academic journals established in 1973
English-language journals
Energy and fuel journals
Monthly journals |
https://en.wikipedia.org/wiki/ForgeRock | ForgeRock, Inc. is an identity and access management software company headquartered in San Francisco. On August 23, 2023, Thoma Bravo announced that it had completed the acquisition of the company for approximately $2.3 billion. Additionally, it reported that ForgeRock has been integrated into its portfolio company Ping Identity.
Overview
ForgeRock was founded in Norway in February 2010 by a group of former Sun Microsystems employees, after Sun was acquired by Oracle Corporation. After the acquisition, the software was scheduled for phase-out in favor of Oracle’s in-house product, so the founders "started their own company to fork the code and continue developing Sun’s software."
In April 2020, ForgeRock announced that it has raised $93.5 million in funding, a Series E it will use to continue expanding, which "brings the total raised by the company to $230 million." The company went public in September 2021. It is listed on the New York Stock Exchange under the ticker symbol FORG. On October 11, 2022, private equity firm, Thoma Bravo, agreed to purchase ForgeRock for $2.3 billion in an all-cash deal. After the acquisition was completed in August 2023, the new owner reported that ForgeRock would be integrated into its company portfolio Ping Identity.
Products
The ForgeRock Identity Platform includes Access Management (based on the OpenAM open source project), Identity Management (based on the OpenIDM open source project), Directory Services (based on the OpenDJ open source project), and Identity Gateway (based on the OpenIG open source project). ForgeRock Access Management provides access management, ForgeRock Directory Services is an LDAP directory service, ForgeRock Identity Management is used for identity management, and ForgeRock Identity Gateway provides an identity gateway for web traffic and application programming interfaces (APIs).
Originally based on open source software owned by Sun Microsystems (now Oracle Corporation), the enterprise version of the |
https://en.wikipedia.org/wiki/Steirastoma%20pustulata | Steirastoma pustulata is a species of beetle in the family Cerambycidae. It was described by Dru Drury in 1773 from Jamaica.
Description
General colour grey brown. Head furnished with strong mandibles. Antennae (with the basal joint very thick) much longer than the insect. Thorax rough, gibbous, and full of small pustules, two of which form an obtuse spine on the sides. Scutellum small and triangular. Elytra margined, and full of small pustules, having two spines fixed at their extremity, near the suture. Forelegs long. Tibiae with a single spur. Femora clavate. Body length about 1 inch (25 mm).
References
Acanthoderini
Beetles described in 1773
Descriptions from Illustrations of Exotic Entomology
Taxa named by Dru Drury |
https://en.wikipedia.org/wiki/Peter%20Lorimer%20%28mathematician%29 | Peter James Lorimer (16 April 1939 – 7 February 2010) was a New Zealand mathematician. His research concerned group theory, combinatorics, and Ramsey theory.
Academic career
Born in Christchurch, Lorimer did a BSc / MSc in mathematics at the University of Auckland and won a Commonwealth Scholarship to do a PhD at McGill University in Montreal, which he completed in 1963 under the supervision of Hans Schwerdtfeger. He returned to New Zealand to lecture, first at University of Canterbury and then at University of Auckland.
References
External links
institutional homepage
1939 births
2010 deaths
Group theorists
Combinatorialists
University of Auckland alumni
Academic staff of the University of Auckland
People from Christchurch
McGill University alumni
Academic staff of the University of Canterbury
New Zealand mathematicians
Fellows of the Royal Society of New Zealand |
https://en.wikipedia.org/wiki/GHash.io | GHash.io was a bitcoin mining pool subsidiary of CEX.io that operated from 2013-2016. The pool gained notoriety for briefly controlling more than 51% of bitcoin's computing power in 2014 (notable in that bitcoin was supposedly outside any party's control).
History
GHash.io was founded and owned by CEX.io, a cryptocurrency exchange that continues to operate today. Apart from mining bitcoin, GHash.io hosted a multipool for mining altcoins, as well as separate pools for mining Litecoin, Dogecoin, Auroracoin, and Darkcoin. Altcoin mining options were available for independent miners, while bitcoin mining could also be done in the cloud by purchasing cloud-based mining power on CEX.io.
Traders on CEX.io could buy shares of GHash.io mining hardware to operate on the GHash.io mining pool. After GHash.io closed in 2016, CEX.io continued operating as a bitcoin exchange.
51% attack controversy
The possibility of a 51% attack was feared due to the popularity of GHash.io's mining pool. This kind of attack occurs when a single miner or mining pool is able to mine multiple bitcoin block rewards in a row. This would be a problem for the bitcoin network, because it hypothetically allows the mining pool to double-spend (counterfeit) bitcoins. In July 2014, the GHash.io mining pool briefly exceeded the 51% threshold, which forced the bitcoin community to discuss the possibility of finding a common solution to this threat. The pool developing the majority caused a prominent bitcoin developer Peter Todd to sell half of his holdings. The news reportedly caused bitcoin's price to drop from $633 to $600 at the time.
Since no long-term solution to the 51% problem is known, the participants agreed to implement some temporary measures. GHash.io released a voluntary statement promising that it would not exceed 40% of the overall bitcoin hashrate. Moreover, GHash.io representatives asked other mining pools to follow their example for the sake of the entire bitcoin community. It also state |
https://en.wikipedia.org/wiki/Siegel%27s%20paradox | Siegel's paradox is the phenomenon that uncertainty about future prices can theoretically push rational consumers to temporarily trade away their preferred consumption goods (or currency) for non-preferred goods (or currency), as part of a plan to trade back to the preferred consumption goods after prices become clearer. For example, in some models, Americans can expect to earn more American dollars on average by investing in Euros, while Europeans can expect to earn more Euros on average by investing in American dollars. The paradox was identified by economist Jeremy Siegel in 1972.
Like the related two envelopes problem, the phenomenon is sometimes labeled a paradox because an agent can seem to trade for something of equal monetary value and yet, paradoxically, seem at the same time to gain monetary value from the trade. Closer analysis shows that the "monetary value" of the trade is ambiguous but that nevertheless such trades are often favorable, depending on the scenario.
Apple/orange example
Economist Fischer Black gave the following illustration in 1995. Suppose that the exchange rate between an "apple" country where consumers prefer apples, and an "orange" country where consumers prefer valuable oranges, is currently 1:1, but will change next year to 2:1 or 1:2 with equal probability. Suppose an apple consumer trades an apple to an orange consumer in exchange for an orange. The apple consumer now has given up an apple for an orange, which next year has an expected value of 1.25 apples. The orange consumer now has given up an orange for an apple, which next year has an expected value of 1.25 oranges. Thus both appear to have benefited from the exchange on average. Mathematically, the apparent surplus is related to Jensen's inequality.
Wine example
A more detailed example is a simplified efficient market with two wines, an American wine and a German wine. In November the wines trade 1:1. In December, most consumers will put exactly twice as much value on |
https://en.wikipedia.org/wiki/FCL-Web | FCL-Web is part of Free Pascal's Free Component Library (FCL), focusing on web (related) application development. The package helps users to develop CGI, FastCGI and embedded web server applications, as well as Apache modules. It provides units implementing HTTP(S) protocol and a somewhat low level web application framework, in the form of web modules. Some content producers (e.g. for automatic content generation from dataset) are also provided. Other prominent use is to send/retrieve data from/to web services (possibly using JSON-RPC).
Web Application Support Units
fpcgi, fpfcgi, fphttpapp and fpapache[24] are the units implementing CGI, FastCGI, embedded web server and Apache module respectively. The interface between the units is made similar by utilizing object oriented inheritance. Therefore, a change of used unit in the uses clause is sufficient to create all 4 kinds of web applications, without code changes for the most of the rest of the application. A notable exception might be the need to set port for FastCGI and embedded web server.
Other Units
httpdefs unit defines base classes for cookies, sessions, file uploads, mime handling, HTTP header, request & response
iniwebsession unit implements session management using .ini files
fphttpserver unit provides ready to use multithreaded-able standalone http server
fphttpclient unit provides class to send http requests and retrieve its responses. It implements all available HTTP 1.1 methods.\
fphtml unit provides content producers
fphttp unit provides abstract web framework support using web modules
fpweb unit provides an implementation of fphttp's abstract web framework
fpWeb Framework
fpWeb is a framework built on top of fcl-web units and itself is a part of fcl-web. The architecture is quite modular and a RAD package for use with Lazarus is available. A fpWeb application consists of one or more web modules, with optional one or more web actions for each module.
The framework uses static routing i |
https://en.wikipedia.org/wiki/P-group%20generation%20algorithm | In mathematics, specifically group theory, finite groups of prime power order , for a fixed prime number and varying integer exponents , are briefly called finite p-groups.
The p-group generation algorithm by M. F. Newman
and E. A. O'Brien
is a recursive process for constructing the descendant tree
of an assigned finite p-group which is taken as the root of the tree.
Lower exponent-p central series
For a finite p-group , the lower exponent-p central series (briefly lower p-central series) of
is a descending series of characteristic subgroups of ,
defined recursively by
and , for .
Since any non-trivial finite p-group is nilpotent,
there exists an integer such that
and is called the exponent-p class (briefly p-class) of .
Only the trivial group has .
Generally, for any finite p-group ,
its p-class can be defined as .
The complete lower p-central series of is therefore given by
,
since is the Frattini subgroup of .
For the convenience of the reader and for pointing out the shifted numeration, we recall that
the (usual) lower central series of is also a descending series of characteristic subgroups of ,
defined recursively by
and , for .
As above, for any non-trivial finite p-group ,
there exists an integer such that
and is called the nilpotency class of ,
whereas is called the index of nilpotency of .
Only the trivial group has .
The complete lower central series of is given by
,
since is the commutator subgroup or derived subgroup of .
The following Rules should be remembered for the exponent-p class:
Let be a finite p-group.
Rule: , since the descend more quickly than the .
Rule: If , for some group , then , for any .
Rule: For any , the conditions and imply .
Rule: Let . If , then , for all , in particular, , for all .
Parents and descendant trees
The parent of a finite non-trivial p-group with exponent-p class
is defined as the quotient of by the last non-trivial term of the lower exponent-p central series of . |
https://en.wikipedia.org/wiki/Digital%20buffer | A digital buffer (or a voltage buffer) is an electronic circuit element used to isolate an input from an output. The buffer's output state mirrors the input state. The buffer's input impedance is high. It draws little current, to avoid disturbing the input circuit. Also called a unity gain buffer, a digital buffer does not intentionally amplify or attenuate the input signal.
The digital buffer is important in data transmission, translating voltage pulses between connected systems. Buffers are used in registers (data storage device) and buses (data transferring device). A tri-state digital buffer can connect a device to a digital bus. The tri-state buffer's output is either high, low, or disconnected.
Functionality
A digital buffer transfers a voltage from a high output impedance circuit to a second circuit with low input impedance. Directly connecting a low impedance load to a power source draws current according to Ohm's law. The high current affects the source. Digital buffer inputs are high impedance. A buffered load effectively does not affect the source circuit. The buffer's output current is generated within the buffer. In this way, a buffer provides isolation between a power source and a low impedance input.
Types
Single input voltage buffer
Inverting buffer
This buffer's output state is the opposite of the input state. If the input is high, the output is low, and vice versa. Graphically, an inverting buffer is represented by a triangle with a small circle at the output, with the circle signifying inversion. The inverter is a basic building block in digital electronics. Decoders, state machines, and other sophisticated digital devices often include inverters.
Non-inverting buffer
This kind of buffer performs no inversion or decision-making possibilities. A single input digital buffer is different from an inverter. It does not invert or alter its input signal in any way. It reads an input and outputs a value. Usually, the input side reads either HIGH |
https://en.wikipedia.org/wiki/LANDR | LANDR Audio is a cloud-based music creation platform developed by MixGenius, an artificial intelligence company based in Montreal, Quebec. Since launching with its flagship automated mastering service in 2014, LANDR has expanded its offerings to include distribution services, a music samples library, virtual studio technology (VSTs) and plug-ins, a service marketplace for musicians, and online video conferencing.
History
MixGenius launched an automated mastering service in 2014 under the name LANDR, meant to represent the left and right audio channels. The engine, developed through several years, was built by analyzing thousands of mastered tracks and by doing research and analysis on the workflows of mastering engineers. The engine performs the standard mastering processes, such as equalization, dynamic compression, audio excitement or saturation, and limiting/maximizing.
The company, now mainly referred to as LANDR Audio, continues to add services to their platform with the goal of bridging the gap between DIY musicians and the professional music market under CEO Pascal Pilon.
LANDR has also created educational materials to help musicians improve their music production skills. Their educational content is disseminated through their blog, social media, and YouTube channel.
Product timeline
2014: AI mastering
2017: Music distribution
2018: Music samples library
2019: Rent-to-own VSTs and plug-ins
2020: Collaboration tools & services marketplace
2021: Proprietary VSTs and plug-ins
Products and services
AI Mastering
Traditional music mastering is a post-production process by which a mastering engineer cleans up and normalizes an audio track to achieve a uniform and consistent master recording from which copies can be reliably made. The LANDR AI engine recreates this process to produce release-ready masters that conform to, both, physical and digital distribution quality standards.
The LANDR engine analyzes uploaded tracks and creates a mastering chain |
https://en.wikipedia.org/wiki/Fraunhofer%20FDK%20AAC | Fraunhofer FDK AAC is an open-source library for encoding and decoding digital audio in the Advanced Audio Coding (AAC) format. Fraunhofer IIS, developed this library for Android 4.1. It supports several Audio Object Types including MPEG-2 and MPEG-4 AAC LC, HE-AAC (AAC LC + SBR), HE-AACv2 (LC + SBR + PS) as well AAC-LD (low delay) and AAC-ELD (enhanced low delay) for real-time communication. The encoding library supports sample rates up to 96 kHz and up to eight channels (7.1 surround).
Operation
The Android-targeted implementation of the Fraunhofer AAC encoder uses fixed-point math and is optimized for encoding on embedded devices/mobile phones. The library is currently limited to 16-bit PCM input. Other versions of the Fraunhofer encoder, like the one included in Winamp, are optimized for encoding music on desktop-class processors. Those versions of the encoder, however, are not open-source and require a commercial license. Version 2 of the library, introduced with Android P, also includes support for xHE-AAC and AAC-ELD v2. xHE-AAC extends the operating range of the codec from 12 to 300 kb/s for stereo signals and allows seamless switching between bitrates over this range for adaptive bitrate delivery (using standards such as MPEG-DASH or HLS for example). xHE-AAC also includes MPEG-D DRC mandatory loudness control to playback content at a consistent volume and offers new dynamic range control profiles for listening in noisy situations.
The FDK AAC encoder employs a more aggressive default low-pass filter than is used in other codecs. Higher frequencies are removed so that more bits are available to better describe sounds of lower frequencies, improving the overall quality for most combinations of recordings and listeners. In some, not completely rare, combinations the missing high frequencies are noticeable. The library allows overriding the low-pass filter setting, and in the highest VBR mode effectively applies no filter at all.
A cross-platform source di |
https://en.wikipedia.org/wiki/Refractive%20index%20and%20extinction%20coefficient%20of%20thin%20film%20materials | A. R. Forouhi and I. Bloomer deduced dispersion equations for the refractive index, n, and extinction coefficient, k, which were published in 1986 and 1988. The 1986 publication relates to amorphous materials, while the 1988 publication relates to crystalline. Subsequently, in 1991, their work was included as a chapter in “The Handbook of Optical Constants”. The Forouhi–Bloomer dispersion equations describe how photons of varying energies interact with thin films. When used with a spectroscopic reflectometry tool, the Forouhi–Bloomer dispersion equations specify n and k for amorphous and crystalline materials as a function of photon energy E. Values of n and k as a function of photon energy, E, are referred to as the spectra of n and k, which can also be expressed as functions of the wavelength of light, λ, since E = HC/λ. The symbol h represents Planck’s constant and c, the speed of light in vacuum. Together, n and k are often referred to as the “optical constants” of a material (though they are not constants since their values depend on photon energy).
The derivation of the Forouhi–Bloomer dispersion equations is based on obtaining an expression for k as a function of photon energy, symbolically written as k(E), starting from first principles quantum mechanics and solid state physics. An expression for n as a function of photon energy, symbolically written as n(E), is then determined from the expression for k(E) in accordance to the Kramers–Kronig relations which states that n(E) is the Hilbert transform of k(E).
The Forouhi–Bloomer dispersion equations for n(E) and k(E) of amorphous materials are given as:
The five parameters A, B, C, Eg, and n(∞) each have physical significance. Eg is the optical energy band gap of the material. A, B, and C depend on the band structure of the material. They are positive constants such that 4C-B2 > 0. Finally, n(∞), a constant greater than unity, represents the value of n at E = ∞. The parameters B0 and C0 in the equation for |
https://en.wikipedia.org/wiki/Hybrid%20plasmonic%20waveguide | A hybrid plasmonic waveguide is an optical waveguide that achieves strong light confinement by coupling the light guided by a dielectric waveguide and a plasmonic waveguide. It is formed by separating a medium of high refractive index (usually silicon) from a metal surface (usually gold or silver) by a small gap.
History
Dielectric waveguides use total internal reflection to confine light in a high index region. They can guide light over a long distance with very low loss, but their light confinement ability is limited by diffraction. Plasmonic waveguides, on the other hand, use surface plasmon to confine light near a metal surface. The light confinement ability of plasmonic waveguides is not limited by diffraction, and, as a result, they can confine light to very small volumes. However, these guides suffer significant propagation loss because of the presence of metal as part of the guiding structure. The aim of designing the hybrid plasmonic waveguide was to combine these two different wave guiding schemes and achieve high light confinement without suffering large loss. Many different variations of this structure have been proposed. Many other types of hybrid plasmonic waveguides have been proposed since then to improve light confinement ability or to reduce fabrication complexity.
Principle of operation
The operation of the hybrid plasmonic waveguides can be explained using the concept of mode coupling. The most commonly used hybrid plasmonic waveguide consists of a silicon nanowire placed very near a metal surface and separated by a low index region. The silicon waveguide supports dielectric waveguide mode, which is mostly confined in silicon. The metal surface supports surface plasmon, which is confined near the metal surface. When these two structures are brought close to each other, the dielectric waveguide mode supported by the silicon nanowire couples to the surface plasmon mode supported by the metal surface. As a result of this mode coupling, light b |
https://en.wikipedia.org/wiki/Ulam%27s%20packing%20conjecture | Ulam's packing conjecture, named for Stanislaw Ulam, is a conjecture about the highest possible packing density of identical convex solids in three-dimensional Euclidean space. The conjecture says that the optimal density for packing congruent spheres is smaller than that for any other convex body. That is, according to the conjecture, the ball is the convex solid which forces the largest fraction of space to remain empty in its optimal packing structure. This conjecture is therefore related to the Kepler conjecture about sphere packing. Since the solution to the Kepler conjecture establishes that identical balls must leave ≈25.95% of the space empty, Ulam's conjecture is equivalent to the statement that no other convex solid forces that much space to be left empty.
Origin
This conjecture was attributed posthumously to Ulam by Martin Gardner, who remarks in a postscript added to one of his Mathematical Games columns that Ulam communicated this conjecture to him in 1972. Though the original reference to the conjecture states only that Ulam "suspected" the ball to be the worst case for packing, the statement has been subsequently taken as a conjecture.
Supporting arguments
Numerical experiments with a large variety of convex solids have resulted in each case in the construction of packings that leave less empty space than is left by close-packing of equal spheres, and so many solids have been ruled out as counterexamples of Ulam's conjecture.
Nevertheless, there is an infinite space of possible shapes that have not been ruled out.
Yoav Kallus has shown that at least among point-symmetric bodies, the ball constitutes a local maximum of the fraction of empty space forced.
That is, any point-symmetric solid that does not deviate too much from a ball can be packed with greater efficiency than can balls.
Analogs in other dimensions
The analog of Ulam's packing conjecture in two dimensions would say that no convex shape forces more than ≈9.31% of the plane to remain |
https://en.wikipedia.org/wiki/Beak%20%28bivalve%29 | The beak is part of the shell of a bivalve mollusk, i.e. part of the shell of a saltwater or freshwater clam. The beak is the basal projection of the oldest part of the valve of the adult animal. The beak usually, but not always, coincides with the umbo, the highest and most prominent point on the valve. Because by definition, all bivalves have two valves, the shell of a bivalve has two umbones, and two beaks.
In many species of bivalves the beaks point towards one another. However, in some species of bivalves the beaks point posteriorly, in which case they are referred to as opisthogyrate; in others the beaks point forward, and are described as being prosogyrate.
If the beak is not eroded or worn down at all, it may still be capped with the prodissoconch, which is the larval shell of the animal.
References
Bivalve anatomy
Conchology
Marine biology |
https://en.wikipedia.org/wiki/Symbolic%20power%20of%20an%20ideal | In algebra and algebraic geometry, given a commutative Noetherian ring and an ideal in it, the n-th symbolic power of is the ideal
where is the localization of at , we set is the canonical map from a ring to its localization, and the intersection runs through all of the associated primes of .
Though this definition does not require to be prime, this assumption is often worked with because in the case of a prime ideal, the symbolic power can be equivalently defined as the -primary component of . Very roughly, it consists of functions with zeros of order n along the variety defined by . We have: and if is a maximal ideal, then .
Symbolic powers induce the following chain of ideals:
Uses
The study and use of symbolic powers has a long history in commutative algebra. Krull’s famous proof of his principal ideal theorem uses them in an essential way. They first arose after primary decompositions were proved for Noetherian rings. Zariski used symbolic powers in his study of the analytic normality of algebraic varieties. Chevalley's famous lemma comparing topologies states that in a complete local domain the symbolic powers topology of any prime is finer than the m-adic topology. A crucial step in the vanishing theorem on local cohomology of Hartshorne and Lichtenbaum uses that for a prime defining a curve in a complete local domain, the powers of are cofinal with the symbolic powers of . This important property of being cofinal was further developed by Schenzel in the 1970s.
In algebraic geometry
Though generators for ordinary powers of are well understood when is given in terms of its generators as , it is still very difficult in many cases to determine the generators of symbolic powers of . But in the geometric setting, there is a clear geometric interpretation in the case when is a radical ideal over an algebraically closed field of characteristic zero.
If is an irreducible variety whose ideal of vanishing is , then the differential power of c |
https://en.wikipedia.org/wiki/Program%20equilibrium | Program equilibrium is a game-theoretic solution concept for a scenario in which players submit computer programs to play the game on their behalf and the programs can read each other's source code. The term was introduced by Moshe Tennenholtz in 2004. The same setting had previously been studied by R. Preston McAfee, J. V. Howard and Ariel Rubinstein.
Setting and definition
The program equilibrium literature considers the following setting. Consider a normal-form game as a base game. For simplicity, consider a two-player game in which and are the sets of available strategies and and are the players' utility functions. Then we construct a new (normal-form) program game in which each player chooses a computer program . The payoff (utility) for the players is then determined as follows. Each player's program is run with the other program as input and outputs a strategy for Player . For convenience one also often imagines that programs can access their own source code. Finally, the utilities for the players are given by for , i.e., by applying the utility functions for the base game to the chosen strategies.
One has to further deal with the possibility that one of the programs doesn't halt. One way to deal with this is to restrict both players' sets of available programs to prevent non-halting programs.
A program equilibrium is a pair of programs that constitute a Nash equilibrium of the program game. In other words, is a program equilibrium if neither player can deviate to an alternative program such that their utility is higher in than in .
Different mechanisms for achieving cooperative program equilibrium in the Prisoner's Dilemma
Various authors have proposed ways to achieve cooperative program equilibrium in the Prisoner's Dilemma.
Cooperation based on syntactic comparison
Multiple authors have independently proposed the following program for the Prisoner's Dilemma:
algorithm CliqueBot(opponent_program):
if opponent_program == t |
https://en.wikipedia.org/wiki/Echo%20%28communications%20protocol%29 | Echo (one-to-all, one-to-one, or one-to-some distribution) is a group communications protocol where authenticated and encrypted information is addressed to members connected to a node.
Adaptive Echo, Full Echo, and Half Echo can be chosen as several modes of the encrypted Echo protocol.
The Echo protocol offers three modes of operation: Adaptive Echo, Full Echo, and Half Echo.
Adaptive Echo
The Adaptive Echo distributes messages to parties that have shown awareness of a secret token. The graphic at the side shows the communication example of Hansel and Gretel. Referring to the old fairy tale, both highlight the trees with either "white pebbles" or "bread crumbs" to discover each other in the forest. They wish to communicate without the wicked witch knowing. How can Hansel and Gretel communicate without revealing their communications? The nodes in this example use the token "white pebbles". Because the wicked witch is unaware of the secret token, she will not receive communications from Hansel and Gretel unless, of course, she misbehaves.
Full Echo
Full Echo or simply Echo sends each message to every neighbor. Every neighbor does the same, unless it's the target node of a specific message. In smaller networks, the message should reach every peer. Nodes can be client, server, or both.
Half Echo
The Half Echo sends the message only to a direct neighbor. If configured correctly, the target node will not disperse the received message to other nearby nodes. This allows two neighbors to communicate with each other on dedicated sockets. That is, data from other nodes will not traverse the restricted socket. Though always authenticated and encrypted, the nodes can exclude others from knowing about the communications.
Echo Accounts
Accounts allow for exclusive connections. A server node may establish accounts and then distribute the credentials' information. Accounts create an artificial web of trust without exposing the public encryption key and without attachi |
https://en.wikipedia.org/wiki/Electronic%20Signatures%20Directive | The Electronic Signatures Directive 1999/93/EC was a European Union directive on the use of electronic signatures (e-signatures) in electronic contracts within the European Union (EU).
It was repealed by the eIDAS regulation on 1 July 2016.
Contents
The central provision of the directive is article 5, which requires that electronic signatures are regarded as equivalent to written signatures.
Related acts
COM(2008) 798 final – Not published in the Official Journal
COM(2006) 120 final – Not published in the Official Journal
Official Journal L 175 , 15/07/2003 P. 0045 - 0046
Official Journal L 289 , 16/11/2000 P. 0042 - 0043
Implementation
See also
Electronic signature
United States Electronic Signatures in Global and National Commerce Act
External links
Docusign article on Directive 1999/93/EC
References
European Union directives
1999 in law
1999 in the European Union
English contract law |
https://en.wikipedia.org/wiki/SKA2 | Spindle and kinetochore-associated protein 2 is a protein that in humans is encoded by the SKA2 gene found in chromosome 17. SKA2 is a part of a spindle and kinetochore associated complex also including SKA1 and SKA3 which is responsible for onset of the anaphase in mitosis by regulating chromosomal segregation.
SKA2 may function as a prognostic gene marker for identifying lung cancer as well as a proposed biomarker for suicidal tendencies and post-traumatic stress disorders. The SKA2 gene contains one single-nucleotide polymorphism (SNP) rs7208505 located in the 3' UTR. This genetic variant containing a cytosine (existing in the less common allele) instead of thymine along with epigenetic modification (such as DNA methylation) is correlated with suicidal tendencies and post-traumatic stress.
Discovery
SKA2 protein was first documented as a product of as hypothetical gene FAM33A part of a Spindle and Kinetochore (KT)- associated complex necessary for timely anaphase onset. SKA2 was identified as the partner of SKA1, hence the name in 2006. Later on the 3rd component of the SKA complex was mass spectrometrically identified as C13Orf3 later referred to as SKA3. This complex plays an important role in the cell during mitotic transition from the metaphase to the anaphase.
Protein structure and sub-cellular localization
SKA2 gene product is a 121 amino acid long chain and a molecular weight of 14,188 Da containing mainly 3 helices. Homologues of SKA2 protein being very small are found in several vertebrates but absent in invertebrates.
This protein mainly localizes in the condensed chromosome and to the outer spindle and kinetochore microtubules during mitosis. The SKA2 proteins localizes to the mitotic spindle and kinetochore associated proteins such as SKA1 and SKA3.
Function
The SKA2 is a part of the larger spindle and kinetochore complex which is a sub-complex of the outer kinetochore and binds to the microtubules. This complex is essential for the correctly |
https://en.wikipedia.org/wiki/Convenient%20vector%20space | In mathematics, convenient vector spaces are locally convex vector spaces satisfying a very mild completeness condition.
Traditional differential calculus is effective in the analysis of finite-dimensional vector spaces and for Banach spaces. Beyond Banach spaces, difficulties begin to arise; in particular, composition of continuous linear mappings stop being jointly continuous at the level of Banach spaces, for any compatible topology on the spaces of continuous linear mappings.
Mappings between convenient vector spaces are smooth or if they map smooth curves to smooth curves. This leads to a Cartesian closed category of smooth mappings between -open subsets of convenient vector spaces (see property 6 below). The corresponding calculus of smooth mappings is called convenient calculus.
It is weaker than any other reasonable notion of differentiability, it is easy to apply, but there are smooth mappings which are not continuous (see Note 1).
This type of calculus alone is not useful in solving equations.
The c∞-topology
Let be a locally convex vector space. A curve is called smooth or if all derivatives exist and are continuous. Let be the space of smooth curves. It can be shown that the set of smooth curves does not depend entirely on the locally convex
topology of only on its associated bornology (system of bounded sets); see [KM], 2.11.
The final topologies with respect to the following sets of mappings into coincide; see [KM], 2.13.
The set of all Lipschitz curves (so that is bounded in for each ).
The set of injections where runs through all bounded absolutely convex subsets in and where is the linear span of equipped with the Minkowski functional
The set of all Mackey convergent sequences (there exists a sequence with bounded).
This topology is called the -topology on and we write for the resulting topological space.
In general (on the space of smooth functions with compact support on the real line, for example) it is finer t |
https://en.wikipedia.org/wiki/DataDirect%20Networks | DataDirect Networks (DDN) is a privately-held data storage company, and is headquartered in Chatsworth, California, USA.
Summary
DDN provides storage systems for unstructured data and big data, like AI, analytics and high performance computing (HPC) environments, in enterprise, government and academia sectors.
Although privately-held, DDN announced that it had achieved annual revenue of $400 million and its highest profitability in 2020. With more than 11,000 customers and a network of resellers and distributors, DDN delivered 52 percent in revenue growth from 2018 to 2020. 2020 was also the fifth consecutive year of customer expansion, and revenue and profitability growth for DDN.
DDN provides storage for applications such as cloud storage services, supercomputing, life sciences and genomics, seismic processing, financial service trade and risk analysis, film production, live television broadcast, manufacturing, and video surveillance.
History
DataDirect Networks, Inc, was formed in 1998 from the merger of two earlier companies, MegaDrive and ImpactData. Alex Bouzari is the company's CEO, chairman and co-founder. Paul Bloch is president and co-founder.
DDN concentrated on building high speed disk storage systems for customers like NASA, eventually delivering storage to five of their systems - Columbia, Schirra, RTJones, Hyperwall-2 and Pleiades by 2008. With the explosion of “Big Data,” Alex Bouzari and Paul Bloch realised that a wider "transformative" event was happening in IT, and that HPC-class storage would be needed for high-end analytics and data processing, with lightning-fast IO, and the ability to scale to much higher capacities. Rather than follow a larger market served by mainstream system and storage vendors, Bouzari and Bloch decided to focus exclusively on fast access and high-capacity storage, particularly for unstructured data.
DDN completed a $9.9 million round of venture capital financing in October 2001 with ClearLight Partners LLC and |
https://en.wikipedia.org/wiki/Chamfer%20%28geometry%29 | In geometry, chamfering or edge-truncation is a topological operator that modifies one polyhedron into another. It is similar to expansion, moving faces apart and outward, but also maintains the original vertices. For polyhedra, this operation adds a new hexagonal face in place of each original edge.
In Conway polyhedron notation it is represented by the letter . A polyhedron with edges will have a chamfered form containing new vertices, new edges, and new hexagonal faces.
Chamfered Platonic solids
In the chapters below the chamfers of the five Platonic solids are described in detail. Each is shown in a version with edges of equal length and in a canonical version where all edges touch the same midsphere. (They only look noticeably different for solids containing triangles.) The shown duals are dual to the canonical versions.
Chamfered tetrahedron
The chamfered tetrahedron (or alternate truncated cube) is a convex polyhedron constructed as an alternately truncated cube or chamfer operation on a tetrahedron, replacing its 6 edges with hexagons.
It is the Goldberg polyhedron GIII(2,0), containing triangular and hexagonal faces.
Chamfered cube
The chamfered cube is a convex polyhedron with 32 vertices, 48 edges, and 18 faces: 12 hexagons and 6 squares. It is constructed as a chamfer of a cube. The squares are reduced in size and new hexagonal faces are added in place of all the original edges. Its dual is the tetrakis cuboctahedron.
It is also inaccurately called a truncated rhombic dodecahedron, although that name rather suggests a rhombicuboctahedron. It can more accurately be called a tetratruncated rhombic dodecahedron because only the order-4 vertices are truncated.
The hexagonal faces are equilateral but not regular. They are formed by a truncated rhombus, have 2 internal angles of about 109.47°, or , and 4 internal angles of about 125.26°, while a regular hexagon would have all 120° angles.
Because all its faces have an even number of sides with |
https://en.wikipedia.org/wiki/Chamfered%20square%20tiling | In geometry, the chamfered square tiling or semitruncated square tiling is a tiling of the Euclidean plane. It is a square tiling with each edge chamfered into new hexagonal faces.
It can also be seen as the intersection of two truncated square tilings with offset positions. And its appearance is similar to a truncated square tiling, except only half of the vertices have been truncated, leading to its descriptive name semitruncated square tiling.
Usage and Names in tiling patterns
In floor tiling, this pattern with small squares has been labeled as Metro Broadway Matte and alternate corner square tile.
With large squares it has been called a Dijon tile pattern.
As 3 rows of rectangles, it has been called a basketweave tiling and triple block tile pattern .
Variations
Variations can be seen in different degrees of truncation. As well, geometric variations exist within a given symmetry. The second row shows the tilings with a 45 degree rotation which also look a little different.
Lower symmetry forms are related to the cairo pentagonal tiling with axial edges expanded into rectangles.
The chiral forms be seen as two overlapping pythagorean tilings.
Semikis square tiling
The dual tiling looks like a square tiling with half of the squares divided into central triangles. It can be called a semikis square tiling, as alternate squares with kis operator applied. It can be seen as 4 sets of parallel lines.
References
Euclidean tilings |
https://en.wikipedia.org/wiki/Henry%20Forder | Henry George Forder (27 September 1889 – 21 September 1981) was a New Zealand mathematician.
Academic career
Born in Shotesham All Saints, near Norwich, he won a scholarships first to a Grammar school and then to University of Cambridge. After teaching mathematics at a number of schools, he was appointed to the chair of mathematics at Auckland University College in New Zealand in 1933. He was very critical of the state of the New Zealand curriculum and set about writing a series of well received textbooks.
His Foundations of Euclidean Geometry (1927) was reviewed by F.W. Owens, who noted that 40 pages are devoted to "concepts of classes, relations, linear order, non archimedean systems, ..." and that order axioms together with a continuity axiom and a Euclidean parallel axiom are the required foundation.
The object achieved is a "continuous and rigorous development of the [Euclidean] doctrine in the light of modern investigations."
In 1929 Forder obtained drawings and notes of Robert William Genese on the exterior algebra of Grassmann. He relied on methods of H. F. Baker in Principles of Geometry to extend Genese's beginning into a complete development with applications throughout geometry. When The Calculus of Extension appeared in 1941 it was reviewed by Homer V. Craig: "The theorem density is exceptionally high and consequently despite the superior exposition it is not an easy book to work straight through – perhaps the key chapters suffer from a lack of recapitulation...
[It] provides the best exposition of the fundamental processes of the Ausdehnungslehre and the most inclusive treatment of the geometrical applications available at present."
Henry Forder was elected Fellow of the Royal Society of New Zealand in 1947 and received an honorary DSc from the University of Auckland in 1959.
Forder lectureship
The Forder Lectureship was established jointly by the London Mathematical Society and the New Zealand Mathematical Society in his honour in 1986.
Sel |
https://en.wikipedia.org/wiki/ATEN%20International | ATEN International Co.(Ltd) () is a multinational manufacturer of connectivity and access management hardware headquartered in Xizhi District, New Taipei, Taiwan. Its products include KVM switches, audiovisual switches and matrices, intelligent power distribution units, information technology management systems, and interface adapters. ATEN has subsidiaries in several countries and is the parent company of IOGEAR.
History
The manufacturer was firstly founded in 1979, and their first products became available in 1981.
In 1999, the company became an public company and established IOGEAR, a subsidiary with which foucses on consumer electronics and information technology which is US-based.
In 2000, the company developed the first 4-port USB 2.0 hub, which became a USB testing standard for the USB Implementers Forum, Inc.
The company went public in 2003 and has since remained the only listed KVM manufacturer in the world.
In 2010, ATEN began offering professional-grade audiovisual (VanCryst) and green energy (NRGence) products, respectively.
In 2012, ATEN collaborated with the National Taiwan University of Science and Technology to develop "iListen", software aimed at helping the hearing-impaired. The following year, ATEN joined the HDBaseT Alliance and began developing video extenders and matrices featuring HDBaseT technology.
Operations
ATEN has subsidiaries in the United States (established in 1996), Belgium (2000), Japan (2004), the United Kingdom (2006), South Korea (2007), China (2007), and Australia (2015); a representative office in Russia (2013); factories in Taiwan and China (2008); and R&D centers in Taiwan, China, and Canada (1998).
Products
ATEN products use proprietary Application-specific integrated circuit (ASIC) technology, incorporating over 220 patents.
As of July 2015, ATEN holds 466 approved global patents.
KVM
KVM Switches: Desktop, Cat 5, over IP, Matrix, Rack, Secure
Computer Sharing Devices
Extenders
Modules & Accessories
Ma |
https://en.wikipedia.org/wiki/0music | 0music is the second album produced with Melomics technology. While the first one (Iamus' album) is a compilation of contemporary pieces fully composed by Iamus, 0music compiles pieces of popular genres, composed and interpreted without any human intervention by Melomics109, a computer cluster hosted at the University of Malaga. The pieces in this album, and all the production of Melomics109, is distributed under CC0 licensing, and it is available in audible and editable (MIDI) formats.
The album was launched during a one-day symposium held in Malaga on July 21, 2014.
Track listing
See also
1 the Road
External links
Melomics Playlist
0music in YouTube
References
2012 albums
Artificial intelligence art
Music technology
Spanish Supercomputing Network |
https://en.wikipedia.org/wiki/Prime%20avoidance%20lemma | In algebra, the prime avoidance lemma says that if an ideal I in a commutative ring R is contained in a union of finitely many prime ideals Pi's, then it is contained in Pi for some i.
There are many variations of the lemma (cf. Hochster); for example, if the ring R contains an infinite field or a finite field of sufficiently large cardinality, then the statement follows from a fact in linear algebra that a vector space over an infinite field or a finite field of large cardinality is not a finite union of its proper vector subspaces.
Statement and proof
The following statement and argument are perhaps the most standard.
Statement: Let E be a subset of R that is an additive subgroup of R and is multiplicatively closed. Let be ideals such that are prime ideals for . If E is not contained in any of 's, then E is not contained in the union .
Proof by induction on n: The idea is to find an element that is in E and not in any of 's. The basic case n = 1 is trivial. Next suppose n ≥ 2. For each i, choose
where the set on the right is nonempty by inductive hypothesis. We can assume for all i; otherwise, some avoids all the 's and we are done. Put
.
Then z is in E but not in any of 's. Indeed, if z is in for some , then is in , a contradiction. Suppose z is in . Then is in . If n is 2, we are done. If n > 2, then, since is a prime ideal, some is in , a contradiction.
E. Davis' prime avoidance
There is the following variant of prime avoidance due to E. Davis.
Proof: We argue by induction on r. Without loss of generality, we can assume there is no inclusion relation between the 's; since otherwise we can use the inductive hypothesis.
Also, if for each i, then we are done; thus, without loss of generality, we can assume . By inductive hypothesis, we find a y in J such that . If is not in , we are done. Otherwise, note that (since ) and since is a prime ideal, we have:
.
Hence, we can choose in that is not in . Then, since , the element has the requir |
https://en.wikipedia.org/wiki/Extraordinary%20magnetoresistance | Extraordinary magnetoresistance (EMR) is a geometrical magnetoresistance effect discovered in 2000, where the change in electrical resistance upon the application of a large magnetic field can be greater than 1,000,000% at room temperature (orders of magnitude greater than other magnetoresistance effects such as GMR and CMR). The effect occurs in semiconductor-metal hybrid systems when a transverse magnetic field is applied. Without a magnetic field the system is in a low-resistance state with most of the current flow directed through the metallic region. Upon the application of a large magnetic field the system switches to a state of much higher electrical resistance, due to the Hall angle approaching 90°, with the current flow inside the metallic region dramatically reduced. The effect is influenced greatly by the system geometry, with an enhancement of over four orders of magnitude shown to be possible with an alternative branched geometry. Since the EMR effect occurs at room temperature and does not rely on magnetic materials it has many possible benefits for applications including in the read heads of future hard disk drives.
References
Magnetoresistance
Spintronics
Computer storage technologies |
https://en.wikipedia.org/wiki/Dollar%20%28reactivity%29 | A dollar is a unit of reactivity for a nuclear reactor, calibrated to the interval between the conditions of criticality and prompt criticality. Prompt criticality will result in an extremely rapid power rise, with the resultant destruction of the reactor, unless it is specifically designed to tolerate the condition. A cent is of a dollar.
Meaning and use
Each nuclear fission produces several neutrons that can be absorbed, escape from the reactor, or go on to cause more fissions in a chain reaction. When an average of one neutron from each fission goes on to cause another fission, the reactor is just barely "critical" and the chain reaction proceeds at a constant power level.
Most neutrons produced in fission are "prompt", i.e., created with the fission products in less than about 10 nanoseconds (a "shake" of time), but certain fission products produce additional neutrons when they decay up to several minutes after their creation by fission. These delayed-release neutrons, a few percent of the total, are key to stable nuclear reactor control. Without delayed neutrons, in a reactor that was just barely above critical, reactor power would increase exponentially on millisecond or even microsecond timescales – much too fast to be controlled with current or near-future technology. Such a rapid power increase can also happen in a real reactor when the chain reaction is sustained without the help of the delayed neutrons. This is prompt criticality, the most extreme example of which is an exploding nuclear weapon where considerable design effort goes into keeping the core deep into prompt criticality for as long as possible until the greatest attainable percentage of material has fissioned.
By definition, a reactivity of zero dollars is just barely on the edge of criticality using both prompt and delayed neutrons. A reactivity less than zero dollars is subcritical; the power level will decrease exponentially and a sustained chain reaction will not occur. One dollar is d |
https://en.wikipedia.org/wiki/Caking | Caking is a powder's tendency to form lumps or masses. The formation of lumps interferes with packaging, transport, flowability, and consumption. Usually caking is undesirable, but it is useful when pressing powdered substances into pills or briquettes. Granular materials can also be subject to caking, particularly those that are hygroscopic such as salt, sugar, and many chemical fertilizers. Anticaking agents are commonly added to control caking.
Caking properties must be considered when designing and constructing bulk material handling equipment. Powdered substances that need to be stored, and flow smoothly at some time in the future, are often pelletized or made into pills.
Mechanism
Caking mechanisms depend on the nature of the material. Caking is a consequence of chemical reactions of grain surfaces. Often these reactions involve adsorption of water vapor or other gases. Crystalline solids often cake by formation of liquid bridge between microcrystals and subsequent fusion of a solid bridge. Amorphous materials can cake by glass transitions and changes in viscosity. Polymorphic phase transitions can also induce caking. The caking process can involve electrostatic attractions or the formation of weak chemical bonds between particles.
Anticaking agents
Anticaking agents are chemical compounds that prevent caking. Some anticaking agents function by absorbing excess moisture or by coating particles and making them water-repellent. Calcium silicate (CaSiO3), a common anti-caking agent added to table salt, absorbs both water and oil. Anticaking agents are also used in non-food items such as road salt, fertilisers, cosmetics, synthetic detergents, and in manufacturing applications.
References
Chemical engineering
Particle technology |
https://en.wikipedia.org/wiki/Extracellular%20vesicle | Extracellular vesicles (EVs) are lipid bilayer-delimited particles that are naturally released from almost all types of cells but, unlike a cell, cannot replicate. EVs range in diameter from near the size of the smallest physically possible unilamellar liposome (around 20-30 nanometers) to as large as 10 microns or more, although the vast majority of EVs are smaller than 200 nm. EVs can be divided according to size and synthesis route into exosomes, microvesicles and apoptotic bodies. They carry a cargo of proteins, nucleic acids, lipids, metabolites, and even organelles from the parent cell. EVs carry distinct proteo-transcriptomic signatures that are different from their cancer cell of origin. Most cells that have been studied to date are thought to release EVs, including some archaeal, bacterial, fungal, and plant cells that are surrounded by cell walls. A wide variety of EV subtypes have been proposed, defined variously by size, biogenesis pathway, cargo, cellular source, and function, leading to a historically heterogenous nomenclature including terms like exosomes and ectosomes.
Numerous functions of EVs have been established or postulated. The first evidence for the existence of EVs was enabled by the ultracentrifuge, the electron microscope, and functional studies of coagulation in the mid-20th century. A sharp increase in interest in EVs occurred in the first decade of the 21st century following the discovery that EVs could transfer nucleic acids such as RNA from cell to cell. Associated with EVs from certain cells or tissues, nucleic acids could be easily amplified as markers of disease and also potentially traced back to a cell of origin, such as a tumor cell. When EVs are taken up by other cells, they may alter the behaviour of the recipient cell, for instance EVs released by colorectal cancer cells increase migration of fibroblasts and thus EVs are of importance in forming tumour landscapes. This discovery also implied that EVs could be used for thera |
https://en.wikipedia.org/wiki/ZMapp | ZMapp is an experimental biopharmaceutical drug comprising three chimeric monoclonal antibodies under development as a treatment for Ebola virus disease. Two of the three components were originally developed at the Public Health Agency of Canada's National Microbiology Laboratory (NML), and the third at the U.S. Army Medical Research Institute of Infectious Diseases; the cocktail was optimized by Gary Kobinger, a research scientist at the NML and underwent further development under license by Mapp Biopharmaceutical. ZMapp was first used on humans during the Western African Ebola virus epidemic, having only been previously tested on animals and not yet subjected to a randomized controlled trial. The National Institutes of Health (NIH) ran a clinical trial starting in January 2015 with subjects from Sierra Leone, Guinea, and Liberia aiming to enroll 200 people, but the epidemic waned and the trial closed early, leaving it too statistically underpowered to give a meaningful result about whether ZMapp worked.
In 2016, a clinical study comparing ZMapp to the current standard of care for Ebola was inconclusive.
Chemistry
The drug is composed of three monoclonal antibodies (mAbs), initially harvested from mice exposed to Ebola virus proteins, that have been chimerized with human constant regions. The components are chimeric monoclonal antibody c13C6 from a previously existing antibody cocktail called "MB-003" and two chimeric mAbs from a different antibody cocktail called ZMab, c2G4, and c4G7. ZMapp is manufactured in the tobacco plant Nicotiana benthamiana in the bioproduction process known as "pharming" by Kentucky BioProcessing, a subsidiary of Reynolds American.
Mechanism of action
Like intravenous immunoglobulin therapy, ZMapp contains a mixture of neutralizing antibodies that confer passive immunity to an individual, enhancing the normal immune response, and is designed to be administered after exposure to the Ebola virus. Such antibodies have been used in the tr |
https://en.wikipedia.org/wiki/Approximation%20property%20%28ring%20theory%29 | In algebra, a commutative Noetherian ring A is said to have the approximation property with respect to an ideal I if each finite system of polynomial equations with coefficients in A has a solution in A if and only if it has a solution in the I-adic completion of A. The notion of the approximation property is due to Michael Artin.
See also
Artin approximation theorem
Popescu's theorem
Notes
References
Ring theory |
https://en.wikipedia.org/wiki/TringMe | TringMe is an Indian internet telephony company based in Bangalore. It focuses on a Flash-based browser client and the related API.
History
It was founded by Yusuf Motiwala & Apul Nahata in 2007, after Yusuf's father complained of downloads required to use VoIP programs. The firm focused on a browser-based app. The duo invested of their own money initially in the venture. In October 2009, TringMe released a Facebook app. It won the NASSCOM's Most Innovative Startup award in 2009.
See also
Skype
Gizmo5
References
External links
Official website
VoIP companies
Android (operating system) software
IOS software |
https://en.wikipedia.org/wiki/Web%20Mercator%20projection | Web Mercator, Google Web Mercator, Spherical Mercator, WGS 84 Web Mercator or WGS 84/Pseudo-Mercator is a variant of the Mercator map projection and is the de facto standard for Web mapping applications. It rose to prominence when Google Maps adopted it in 2005. It is used by virtually all major online map providers, including Google Maps, CARTO, Mapbox, Bing Maps, OpenStreetMap, Mapquest, Esri, and many others. Its official EPSG identifier is EPSG:3857, although others have been used historically.
Properties
Web Mercator is a slight variant of the Mercator projection, one used primarily in Web-based mapping programs. It uses the same formulas as the standard Mercator as used for small-scale maps. However, the Web Mercator uses the spherical formulas at all scales whereas large-scale Mercator maps normally use the ellipsoidal form of the projection. The discrepancy is imperceptible at the global scale but causes maps of local areas to deviate slightly from true ellipsoidal Mercator maps at the same scale. This deviation becomes more pronounced further from the equator, and can reach as much as 40 km on the ground.
While the Web Mercator's formulas are for the spherical form of the Mercator, geographical coordinates are required to be in the WGS 84 ellipsoidal datum. This discrepancy causes the projection to be slightly non-conformal. General lack of understanding that the Web Mercator differs from standard Mercator usage has caused considerable confusion and misuse. For all these reasons, the United States Department of Defense through the National Geospatial-Intelligence Agency has declared this map projection to be unacceptable for any official use.
Unlike most map projections for the sphere, the Web Mercator uses the equatorial radius of the WGS 84 spheroid, rather than some compromise between the equatorial and polar radii. This results in a slightly larger map compared to the map's stated (nominal) scale than for most maps.
Formulas
Formulas for the Web M |
https://en.wikipedia.org/wiki/2014%20Russian%20hacker%20password%20theft | The 2014 Russian hacker password theft is an alleged hacking incident resulting in the possible theft of over 1.2 billion internet credentials, including usernames and passwords, with hundreds of millions of corresponding e-mail addresses. The data breach was first reported by The New York Times after being allegedly discovered and reported by Milwaukee-based information security company, Hold Security.
420,000 websites are reported to be affected. According to The New York Times, some big companies knew that their user's credentials are among the stolen. Hold Security did not disclose which sites were compromised, but, instead, offered two separate services, one for website owners and one for consumers to check if they're affected. The service for website owners costs $10 a month. The check for consumers is free.
Hold Security described the group responsible for the hack as a small group of "fewer than a dozen men in their 20s ... based in a small city in south central Russia, the region flanked by Kazakhstan and Mongolia", and dubbed the group CyberVor (Russian, lit. "cyber thief"). Hold claimed the hack was perpetrated through the use of SQL injection. According to a Forbes article, Hold Security says that not all the 1.2 billion credentials were stolen this way, there are also ones that CyberVor simply bought from people that used other means, and Hold Security doesn't know what the split is.
Criticism of Hold Security
Forbes columnist, Kashmir Hill, noted "The Internet predictably panicked as the story of yet another massive password breach went viral." and "[T]his is a pretty direct link between a panic and a pay-out for a security firm." Hold Security's website has a service offering people to check if their username and password pair has been stolen. It requires people to send Hold Security encrypted versions of their passwords.
Skepticism
No named independent sources came forward to confirm the breach, and Forbes columnist, Joseph Steinberg, even e |
https://en.wikipedia.org/wiki/Genetic%20resources | Genetic resources are genetic material of actual or potential value, where genetic material means any material of plant, animal, microbial or other origin containing functional units of heredity.
Genetic resources is one of the three levels of biodiversity defined by the Convention on Biological Diversity in Rio, 1992.
Examples
Animal genetic resources for food and agriculture
Forest genetic resources
Germplasm, genetic resources that are preserved for various purposes such as breeding, preservation, and research
Plant genetic resources
See also
Cryoconservation of animal genetic resources, a strategy to preserve genetic resources cryogenically
Commission on Genetic Resources for Food and Agriculture, the only permanent intergovernmental body that addresses biological diversity for food and agriculture
International Treaty on Plant Genetic Resources for Food and Agriculture, an international agreement to promote sustainable use of the world's plant genetic resources
Gene bank, a type of biorepository which preserves genetic material
Genetic diversity
The State of the World's Animal Genetic Resources for Food and Agriculture
References
Genetics
Biodiversity |
https://en.wikipedia.org/wiki/Golden%20Gate%20Cloning | Golden Gate Cloning or Golden Gate assembly is a molecular cloning method that allows a researcher to simultaneously and directionally assemble multiple DNA fragments into a single piece using Type IIS restriction enzymes and T4 DNA ligase. This assembly is performed in vitro. Most commonly used Type IIS enzymes include BsaI, BsmBI, and BbsI.
Unlike standard Type II restriction enzymes like EcoRI and BamHI, these enzymes cut DNA outside of their recognition sites and, therefore, can create non-palindromic overhangs. Since 256 potential overhang sequences are possible, multiple fragments of DNA can be assembled by using combinations of overhang sequences. In practice, this means that Golden Gate Cloning is typically scarless. Additionally, because the final product does not have a Type IIS restriction enzyme recognition site, the correctly-ligated product cannot be cut again by the restriction enzyme, meaning the reaction is essentially irreversible. This means that it is possible to do the digestion and ligation of the DNA fragments in a single reaction, whereas in conventional cloning methods these reactions are separate.
A typical thermal cycler protocol oscillates between 37 °C (optimal for restriction enzymes) and 16 °C (optimal for ligases) many times. While this technique can be used for a single insert, researchers have used Golden Gate Cloning to assemble many pieces of DNA simultaneously.
Seamless Cloning
Scar sequences are common in multiple segment DNA assembly. In the multisegment assembly method Gateway, segments are added into the donor with additional ATT sequences, which overlap in those added segments, and this results in the segments separated by the ATT sequences. In BioBrick assembly, an eight-nucleotide scar sequence, which codes for a tyrosine and a stop codon, is left between every segment added into the plasmid.
Golden Gate assembly uses Type IIS restriction enzymes cutting outside their recognition sequences. Also, the same Type IIS r |
https://en.wikipedia.org/wiki/Unified%20Diagnostic%20Services | Unified Diagnostic Services (UDS) is a diagnostic communication protocol used in electronic control units (ECUs) within automotive electronics, which is specified in the ISO 14229-1. It is derived from ISO 14230-3 (KWP2000) and the now obsolete ISO 15765-3 (Diagnostic Communication over Controller Area Network (DoCAN)). 'Unified' in this context means that it is an international and not a company-specific standard. By now this communication protocol is used in all new ECUs made by Tier 1 suppliers of Original Equipment Manufacturer (OEM), and is incorporated into other standards, such as AUTOSAR. The ECUs in modern vehicles control nearly all functions, including electronic fuel injection (EFI), engine control, the transmission, anti-lock braking system, door locks, braking, window operation, and more.
Diagnostic tools are able to contact all ECUs installed in a vehicle, which has UDS services enabled. In contrast to the CAN bus protocol, which only uses the first and second layers of the OSI model, UDS utilizes the fifth and seventh layers of the OSI model. The Service ID (SID) and the parameters associated with the services are contained in the payload of a message frame.
Modern vehicles have a diagnostic interface for off-board diagnostics, which makes it possible to connect a computer (client) or diagnostics tool, which is referred to as tester, to the communication system of the vehicle. Thus, UDS requests can be sent to the controllers which must provide a response (this may be positive or negative). This makes it possible to interrogate the fault memory of the individual control units, to update them with new firmware, have low-level interaction with their hardware (e.g. to turn a specific output on or off), or to make use of special functions (referred to as routines) to attempt to understand the environment and operating conditions of an ECU to be able to diagnose faulty or otherwise undesirable behavior.
Services
SID (Service Identifier)
See also
On- |
https://en.wikipedia.org/wiki/National%20Wind%20Tunnel%20Facility | The National Wind Tunnel Facility (NWTF), is an initiative in which 17 wind tunnels distributed across seven UK universities (host institutions) are made open access (for up to 25% of time) to external researchers in the UK and abroad, from both university and industry based.
NWTF is intended to be as inclusive as possible while still supporting the best science. The scheme was announced on 9 January 2014 by David Willetts, Minister for Science and Universities. The total funding for the Facility is £13.3 million, £10.7 million coming from EPSRC and £2.6 million from the UK Aerospace Technology Institute.
The EPSRC and ATI decided to fund the NWTF in order to match the UK talent base to world-class wind tunnel facilities. The enhanced UK capability in experimental aerodynamics is available to all UK-based researchers. The stated aim was to create nodes of excellence attracting young researchers. Another aim was to establish a closer tie with industry, creating a pull-through environment and an intended spill-over of the collaboration and benefits to other sectors.
The NWTF programme was to have a duration of five years. A mid-term review was to review the progress made during the first two and a half years. The current end date is December 2018,
Wind tunnels available
Governance
The NWTF has a management board (MB) that meets approximately every 3 months. This is composed of a Principal Investigator from each of the current host institutions and the NWTF Project Manager. The current MB members are Professor Holger Babinsky (University of Cambridge), Professor Chris Atkin (City University), Professor Kevin Garry (Cranfield University), Dr Richard Green (University of Glasgow), Professor Jonathan Morrison (Imperial College), Professor Peter Ireland (University of Oxford), Professor Bharathram Ganapathisubramani (University of Southampton) and Dr Kevin Gouder (NWTF Project Manager).
An advisory board (AB) oversees the broader aims of the NWTF, monitors the ru |
https://en.wikipedia.org/wiki/Gradient-domain%20image%20processing | Gradient domain image processing, also called Poisson image editing, is a type of digital image processing that operates on the differences between neighboring pixels, rather than on the pixel values directly. Mathematically, an image gradient represents the derivative of an image, so the goal of gradient domain processing is to construct a new image by integrating the gradient, which requires solving Poisson's equation.
Overview
Processing images in the gradient domain is a two-step process. The first step is to choose an image gradient. This is often extracted from one or more images and then modified, but it can be obtained through other means as well. For example, some researchers have explored the advantages of users painting directly in the gradient domain, while others have proposed sampling a gradient directly from a camera sensor. The second step is to solve Poisson's equation to find a new image that can produce the gradient from the first step. An exact solution often does not exist because the modified gradient field is no longer conservative, so an image is found that approximates the desired gradient as closely as possible.
Image editing
For image editing purposes, the gradient is obtained from an existing image and modified. Various operators, such as finite difference or Sobel, can be used to find the gradient of a given image. This gradient can then be manipulated directly to produce a number of different effects when the resulting image is solved for. For example, if the gradient is scaled by a uniform constant it results in a simple sharpening filter. A better sharpening filter can be made by only scaling the gradient in areas deemed important.
Other uses include seamless image stitching, removal of unwanted details from an image, non-photorealistic rendering filters, image deblocking,
the ability to seamlessly clone one part of an image onto another in ways that are difficult to achieve with conventional image-domain techniques, and high-dyn |
https://en.wikipedia.org/wiki/Mount%20Polley%20mine | The Mount Polley mine is a Canadian gold and copper mine located in British Columbia near the towns of Williams Lake, and Likely. It consists of two open-pit sites with an underground mining component and is owned and operated by the Mount Polley Mining Corporation, a wholly owned subsidiary of Imperial Metals. In 2013, the mine produced an output of of copper, 45,823 ounces of gold, and 123,999 of silver. The mill commenced operations in 1997 and was closed and placed on care and maintenance in 2019. The company owns of property near Quesnel Lake and Polley Lake where it has mining leases and operations on and mineral claims on . Mineral concentrate is delivered by truck to the Port of Vancouver.
As of January 2020, Mount Polley's Proven and Probable Reserves were 53.8 million tonnes of ore grading 0.34% copper, 0.30 grams per tonne gold and 0.9 grams per tonne silver, equating to 400 million pounds of copper, 517,000 troy ounces of gold and 1.55 million troy ounces of silver.
Mount Polley Mining Company is targeting a September 2021 reopening to meet global demand for copper and gold. Mount Polley Mining Company estimates that the reopening of the mine will create 300 local jobs. Mount Polley is planning to reopen in the spring of 2022 to meet the global demand of copper and gold. The Mount Polley Mining Corporation estimates that the reopening of the mine will add 300 local jobs.
Mining operations
When operating, the Mount Polley mine moves 80,000-90,000 tonnes of material per day from the mine. This consists of 20,000 tonnes of ore.
Mount Polley does not require high-skilled labour for operations and hires and trains from the local communities of Big Lake, Horsefly and as far away as Quesnel and Williams Lake. Most workers come from communities near the mine.
Minerals
Mount Polley determines what qualifies as ore and what qualifies as waste using drilling and blasting. Ore is then sorted according to blast ball assays. High value sulfide ore is hauled |
https://en.wikipedia.org/wiki/Blend4Web | Blend4Web is a free and open source framework for creating and displaying interactive 3D computer graphics in web browsers.
Overview
The Blend4Web framework leverages Blender to edit 3D scenes. Content rendering relies on WebGL, Web Audio, WebVR, and other web standards, without the use of plug-ins.
It is dual-licensed and is distributed under the free and open source GPLv3 and a non-free license; the source code is hosted on GitHub.
A 3D scene can be prepared in Blender and then exported as a pair of JSON and binary files to load in a web application. It can also be exported as a single, self-contained HTML file, in which exported data, the web player GUI and the engine itself are packed. The HTML option is considered to be the simplest way. The resulting file, which has a minimum size of 1 MB, can be embedded in a web page using a standard iframe HTML element. Blend4Web-powered web applications can be deployed on social networking websites such as Facebook.
The Blend4Web toolchain consists of JavaScript libraries, the Blender add-on, and a set of tools for tweaking 3D scene parameters, debugging, and optimization.
Developed by Moscow-based company Triumph in 2010, Blend4Web was publicly released on March 28, 2014.
At the end of 2017, the project founders Yuri and Alex Kovelenov quit Triumph to start the development of a new WebGL framework Verge3D.
In October 2019, an "Absolutely new Blend4Web" was announced, planned to make developing 3D apps easier and to add a new marketplace where people can offer their 3D models.
Features
The framework has a number of components typically found in game engines, including a positional audio system, physics engine (a fork of Bullet ported to JavaScript), animation system, and an abstraction layer for game logic programming.
Up to 8 different types of animations can be assigned to a single object, including skeletal and per-vertex animation. The speed and the direction of animation (forward/backward play), as well as |
https://en.wikipedia.org/wiki/Quantifier%20%28logic%29 | In logic, a quantifier is an operator that specifies how many individuals in the domain of discourse satisfy an open formula. For instance, the universal quantifier in the first order formula expresses that everything in the domain satisfies the property denoted by . On the other hand, the existential quantifier in the formula expresses that there exists something in the domain which satisfies that property. A formula where a quantifier takes widest scope is called a quantified formula. A quantified formula must contain a bound variable and a subformula specifying a property of the referent of that variable.
The most commonly used quantifiers are and . These quantifiers are standardly defined as duals; in classical logic, they are interdefinable using negation. They can also be used to define more complex quantifiers, as in the formula which expresses that nothing has the property . Other quantifiers are only definable within second order logic or higher order logics. Quantifiers have been generalized beginning with the work of Mostowski and Lindström.
In a first-order logic statement, quantifications in the same type (either universal quantifications or existential quantifications) can be exchanged without changing the meaning of the statement, while the exchange of quantifications in different types changes the meaning. As an example, the only difference in the definition of uniform continuity and (ordinary) continuity is the order of quantifications.
First order quantifiers approximate the meanings of some natural language quantifiers such as "some" and "all". However, many natural language quantifiers can only be analyzed in terms of generalized quantifiers.
Relations to logical conjunction and disjunction
For a finite domain of discourse , the universally quantified formula is equivalent to the logical conjunction .
Dually, the existentially quantified formula is equivalent to the logical disjunction .
For example, if is the set of binary digits, |
https://en.wikipedia.org/wiki/Quantification%20%28science%29 | In mathematics and empirical science, quantification (or quantitation) is the act of counting and measuring that maps human sense observations and experiences into quantities. Quantification in this sense is fundamental to the scientific method.
Natural science
Some measure of the undisputed general importance of quantification in the natural sciences can be gleaned from the following comments:
"these are mere facts, but they are quantitative facts and the basis of science."
It seems to be held as universally true that "the foundation of quantification is measurement."
There is little doubt that "quantification provided a basis for the objectivity of science."
In ancient times, "musicians and artists ... rejected quantification, but merchants, by definition, quantified their affairs, in order to survive, made them visible on parchment and paper."
Any reasonable "comparison between Aristotle and Galileo shows clearly that there can be no unique lawfulness discovered without detailed quantification."
Even today, "universities use imperfect instruments called 'exams' to indirectly quantify something they call knowledge."
This meaning of quantification comes under the heading of pragmatics.
In some instances in the natural sciences a seemingly intangible concept may be quantified by creating a scale—for example, a pain scale in medical research, or a discomfort scale at the intersection of meteorology and human physiology such as the heat index measuring the combined perceived effect of heat and humidity, or the wind chill factor measuring the combined perceived effects of cold and wind.
Social sciences
In the social sciences, quantification is an integral part of economics and psychology. Both disciplines gather data – economics by empirical observation and psychology by experimentation – and both use statistical techniques such as regression analysis to draw conclusions from it.
In some instances a seemingly intangible property may be quantified by asking |
https://en.wikipedia.org/wiki/Grigori%20Mints | Grigori Mints (June 7, 1939 – May 29, 2014) was a Russian philosopher and mathematician who worked in mathematical logic.
He was born in Leningrad, in the Soviet Union (now St. Petersburg, Russia), and received his Ph.D. in 1965 from the Leningrad State University under Nikolai Aleksandrovich Shanin with a thesis entitled "On Predicate and Operator Variants for Building Theories of Constructive Mathematics". In 1990 he received his D.Sc. from Leningrad State University with a thesis entitled "Proof Transformations and Synthesis of Programs". He was a Stanford University professor. Since 1991, Grigori "Grisha" Mints was a professor of philosophy and, by courtesy, of mathematics and of computer science at Stanford University. Before joining Stanford, Mints held research positions at the Steklov Mathematical Institute, Leningrad University, and the Estonian Academy of Sciences.
Considered one of the most distinguished logicians in the world, Mints was passionate about the applications of logic to philosophy. His expertise was in proof theory – the analysis of the structure of mathematical reasoning. Mints was elected to the Estonian Academy of Sciences in 2008 and to the American Academy of Arts and Sciences in 2010.
Mints was a very active member of the steering committee of the WoLLIC series of workshops on logic and language, after having been a member of the community in several capacities such as invited speaker, PC member, PC chair, Organising Committee chair, guest editor of proceedings and special issue, and steering committee member.
Selected publications
Mints, G. (2013) Epsilon substitution for first- and second-order predicate logic. "Ann. Pure Appl. Logic" 164(6): 733-739.
Mints, G., Olkhovikov, G.V., Urquhart, A. (2013) Failure of interpolation in constant domain intuitionistic logic. "J. Symb. Log." 78(3): 937-950.
Mints, G. (2013) ADC Method of Proof Search for Intuitionistic Propositional Natural Deduction. To appear in a "Festsschrift for A. Avr |
https://en.wikipedia.org/wiki/Breed%20method | Breed method is a laboratory technique used for counting microorganisms in milk. It was introduced in 1910 by American biologists Samuel Cate Prescott and Robert Stanley Breed.
Purpose
It is a method for somatic cell count, to know the number of living and dead microorganisms. When the method only recounts living organisms is called "viable count".
There are many methods for the quantification of microorganisms, including microscopy methods, Coulter counter, Mass Spectrometry (for estimating cell mass), and Cell Culture methods which form and grow colonies of bacteria.
The existing security in dairy products is given by the microbiological quality of the same, which ensures consumption from the point of view of health.
The analysis of the quality of raw milk is a common practice in the dairy industry and aims to control the quality of the samples and the material introduced into the processing plant, culminating in a mass-consumption to ensure quality standards.
Sample preparation
It is important first, to homogenize milk, heating it in a water bath at 40 °C for somatic cells that float to the surface along with the fat. The laboratory apparatus must be clean but not necessarily sterile, since the method is based on cell count and asepsis is not accurate. If later it is going to make detailed microbiological analyzes on the same sample, then it is necessary to be obtained and manipulated with sterile material.
After this process, the sample is transported to the laboratory in a 4 °C conservative container. It can be preserved in these conditions for 24 hours.
For sampling there are two basic conditions to consider:
The first one is to represent the total volume of milk from which it was removed, and the second condition involves to be stored and transported at the correct temperature so that they see their unmodified source properties, prior to analysis in the laboratory. In case of delay in completion of the analysis a preservative that not alter the sub |
https://en.wikipedia.org/wiki/Murnaghan%E2%80%93Nakayama%20rule | In group theory, a branch of mathematics, the Murnaghan–Nakayama rule, named after Francis Murnaghan and Tadashi Nakayama, is a combinatorial method to compute irreducible character values of a symmetric group.
There are several generalizations of this rule beyond the representation theory of symmetric groups, but they are not covered here.
The irreducible characters of a group are of interest to mathematicians because they concisely summarize important information about the group, such as the dimensions of the vector spaces in which the elements of the group can be represented by linear transformations that “mix” all the dimensions. For many groups, calculating irreducible character values is very difficult; the existence of simple formulas is the exception rather than the rule.
The Murnaghan–Nakayama rule is a combinatorial rule for computing symmetric group character values χ using a particular kind of Young tableaux.
Here λ and ρ are both integer partitions of some integer n, the order of the symmetric group under consideration. The partition λ specifies the irreducible character, while the partition ρ specifies the conjugacy class on whose group elements the character is evaluated to produce the character value. The partitions are represented as weakly decreasing tuples; for example, two of the partitions of 8 are (5,2,1) and (3,3,1,1).
There are two versions of the Murnaghan-Nakayama rule, one non-recursive and one recursive.
Non-recursive version
Theorem:
where the sum is taken over the set BST(λ,ρ) of all border-strip tableaux of shape λ and type ρ.
That is, each tableau T is a tableau such that
the k-th row of T has λk boxes
the boxes of T are filled with integers, with the integer i appearing ρi times
the integers in every row and column are weakly increasing
the set of squares filled with the integer i form a border strip, that is, a connected skew-shape with no 2×2-square.
The height, ht(T), is the sum of the heights of the border strips in T |
https://en.wikipedia.org/wiki/Laguerre%20formula | The Laguerre formula (named after Edmond Laguerre) provides the acute angle between two proper real lines, as follows:
where:
is the principal value of the complex logarithm
is the cross-ratio of four collinear points
and are the points at infinity of the lines
and are the intersections of the absolute conic, having equations , with the line joining and .
The expression between vertical bars is a real number.
Laguerre formula can be useful in computer vision, since the absolute conic has an image on the retinal plane which is invariant under camera displacements, and the cross ratio of four collinear points is the same for their images on the retinal plane.
Derivation
It may be assumed that the lines go through the origin. Any isometry leaves the absolute conic invariant, this allows to take as the first line the x axis and the second line lying in the plane z=0. The homogeneous coordinates of the above four points are
respectively. Their nonhomogeneous coordinates on the infinity line of the plane z=0 are , , 0, . (Exchanging and changes the cross ratio into its inverse, so the formula for gives the same result.) Now from the formula of the cross ratio we have
References
O. Faugeras. Three-dimensional computer vision. MIT Press, Cambridge, London, 1999.
Equations
Geometry in computer vision |
https://en.wikipedia.org/wiki/Amoeba%20order | In mathematics, the amoeba order is the partial order of open subsets of 2ω of measure less than 1/2, ordered by reverse inclusion. Amoeba forcing is forcing with the amoeba order; it adds a measure 1 set of random reals.
There are several variations, where 2ω is replaced by the real numbers or a real vector space or the unit interval, and the number 1/2 is replaced by some positive number ε.
The name "amoeba order" come from the fact that a subset in the amoeba order can "engulf" a measure zero set by extending a "pseudopod" to form a larger subset in the order containing this measure zero set, which is analogous to the way an amoeba eats food.
The amoeba order satisfies the countable chain condition.
References
Order theory
Forcing (mathematics) |
https://en.wikipedia.org/wiki/Nesreen%20Ghaddar | Nesreen Ghaddar is a professor of mechanical engineering at the American University of Beirut. She is Qatar Chair of Energy Studies and the Director of the Munib and Angela Institute of Energy and Natural Resources at AUB. She obtained her Bachelor in Engineering in 1980 and her Master in 1982 from Kuwait University and her PhD in 1985 from Massachusetts Institute of Technology.
She is an editor of the Journal of Applied Mechanics and a fellow of Islamic World Academy of Sciences.
References
Living people
Lebanese engineers
Academic staff of the American University of Beirut
Year of birth missing (living people)
Fellows of the Islamic World Academy of Sciences |
https://en.wikipedia.org/wiki/X%2BY | X+Y, released in the US as A Brilliant Young Mind, is a 2014 British drama film directed by Morgan Matthews and starring Asa Butterfield, Rafe Spall and Sally Hawkins.
The film, inspired by the 2007 documentary Beautiful Young Minds, focuses on a teenage English mathematics prodigy named Nathan (Asa Butterfield) who has difficulty understanding people, and is autistic, but finds comfort in numbers. When he is chosen to represent the United Kingdom at the International Mathematical Olympiad (IMO), Nathan embarks on a journey in which he faces unexpected challenges, such as understanding the nature of love. The character of Nathan was based on Daniel Lightwing who won a silver medal at the 2006 IMO.
The film premiered at the Toronto International Film Festival on 5 September 2014. The European premiere was at the BFI London Film Festival on 13 October 2014, and the UK cinema release was on 13 March 2015.
Plot
Nathan Ellis, a 9-year-old maths prodigy, has just lost his father in a car accident. Nathan is diagnosed as being on the autism spectrum early in the film, and his father was the only one who was able to connect normally with him. Although Nathan values his mother, Julie, he shuns any physical contact with her and treats her as more of a caretaker than a parent. Wanting to make sure Nathan is not distracted from his studies, Julie enrolls him in advanced classes at a new school (filmed at High Storrs School in Sheffield, United Kingdom). There, he comes under the tutelage of teacher Martin, also a math genius, who has multiple sclerosis. Martin sees himself in Nathan, once a promising young mind in the field of mathematics, who gave it all up once he was diagnosed with his illness.
Seven years later, Martin is preparing Nathan to compete for a place in the International Mathematical Olympiad, a prestigious high school competition consisting of the world's best young mathematicians. This year, it is to be held at Cambridge, after a two-week math camp in Taiw |
https://en.wikipedia.org/wiki/Hanabi%20%28card%20game%29 | Hanabi (from Japanese 花火, fireworks) is a cooperative card game created by French game designer Antoine Bauza and published in 2010. Players are aware of other players' cards but not their own, and attempt to play a series of cards in a specific order to set off a simulated fireworks show. The types of information that players may give to each other is limited, as is the total amount of information that can be given during the game. In 2013, Hanabi won the Spiel des Jahres, an industry award for best board game of the year.
Gameplay
The Hanabi deck contains cards in five suits (white, yellow, green, blue, and red): three 1's, two each of 2's, 3's, and 4's, and one 5. The game begins with 8 available information tokens and 3 fuse tokens. To start the game, players are dealt a hand containing five cards (four for 4 or 5 players). As in Blind Man's Bluff, players can see each other's cards but they cannot see their own. Play proceeds around the table; each turn, a player must take one of the following actions:
Give information: The player points out the cards of either a given number or a given suit in the hand of another player (examples: "This card is your only red card," "These two cards are your only 3's"). The information given must be complete and correct. (In some editions, it is allowed to indicate that a player has zero of something; other versions explicitly forbid this case.) Giving information consumes one information token.
Discard a card: The player chooses a card from their hand and adds it to the discard pile, then draws a card to replace it. The discarded card is out of the game and can no longer be played. Discarding a card replenishes one information token.
Play a card: The player chooses a card from their hand and attempts to add it to the cards already played. This is successful if the card is a 1 in a suit that has not yet been played, or if it is the next number sequentially in a suit that has been played. Otherwise a fuse token is consumed |
https://en.wikipedia.org/wiki/Packing%20density | A packing density or packing fraction of a packing in some space is the fraction of the space filled by the figures making up the packing. In simplest terms, this is the ratio of the volume of bodies in a space to the volume of the space itself. In packing problems, the objective is usually to obtain a packing of the greatest possible density.
In compact spaces
If are measurable subsets of a compact measure space
and their interiors pairwise do not intersect, then the collection is a packing in and its packing density is
.
In Euclidean space
If the space being packed is infinite in measure, such as Euclidean space, it is customary to define the density as the limit of densities exhibited in balls of larger and larger radii. If is the ball of radius centered at the origin, then the density of a packing is
.
Since this limit does not always exist, it is also useful to define the upper and lower densities as the limit superior and limit inferior of the above respectively. If the density exists, the upper and lower densities are equal. Provided that any ball of the Euclidean space intersects only finitely many elements of the packing and that the diameters of the elements are bounded from above, the (upper, lower) density does not depend on the choice of origin, and can be replaced by for every element that intersects .
The ball may also be replaced by dilations of some other convex body, but in general the resulting densities are not equal.
Optimal packing density
One is often interested in packings restricted to use elements of a certain supply collection. For example, the supply collection may be the set of all balls of a given radius. The optimal packing density or packing constant associated with a supply collection is the supremum of upper densities obtained by packings that are subcollections of the supply collection. If the supply collection consists of convex bodies of bounded diameter, there exists a packing whose packing density is equal to |
https://en.wikipedia.org/wiki/Butterfly%20count | Butterfly counts are often carried out in North America and Europe to estimate the populations of butterflies in a specific geographical area.
The counts are conducted by interested, mostly non-professional, residents of the area who maintain an interest in determining the numbers and species of butterflies in their locale. A butterfly count usually occurs at a specific time during the year and is sometimes coordinated to occur with other counts which may include a park, county, entire state or country. The results of the counts are usually shared with other interested parties including professional lepidopterists and researchers. The data gathered during a count can indicate population changes and health within a species.
Sponsors
Professionals, universities, clubs, elementary and secondary schools, other educational providers, nature preserves, parks, and amateur organizations can organize a count. The participants often receive training to help them identify the butterfly species. The North American Butterfly Association organized over 400 counts in 2014.
Types of butterfly counts
There are several methods for counting butterflies currently in use, with the notable division being between restricted and open searches. Most counts are designed to count all butterflies observed in a locality. The purpose of a count is to estimate butterfly populations in a larger area from a smaller sample.
Counts may be targeted at single species and, in some cases, butterflies are observed and counted as they move from one area to another. A heavily researched example of butterfly migration is the annual migration of monarch butterflies in North America. Some programs will tag butterflies to trace their migration routes, but these are migratory programs and not butterfly counts. Butterfly counts are sometimes done where there is a concentration (a roost) of a species of butterflies in an area. One example of this is the winter count of western monarch butterflies as the |
https://en.wikipedia.org/wiki/Caliber%20%28mathematics%29 | In mathematics, the caliber or calibre of a topological space X is a cardinal κ such that for every set of κ nonempty open subsets of X there is some point of X contained in κ of these subsets. This concept was introduced by .
There is a similar concept for posets. A pre-caliber of a poset P is a cardinal κ such that for any collection of elements of P indexed by κ, there is a subcollection of cardinality κ that is centered. Here a subset of a poset is called centered if for any finite subset there is an element of the poset less than or equal to all of them.
References
Topology |
https://en.wikipedia.org/wiki/Calabash%20chalk | Calabash chalk is a geophagic material popularly consumed in West African countries for pleasure, and by pregnant women as a cure for nausea.
Geophagia is the practice of eating the earth, including soil and chalk. This practice is neither new nor outdated and can be associated with religious beliefs, medication or as part of a regular diet. This act can expose the consumer to toxic substances and parasites found in the ingested earth.
Name
Calabash chalk is identified by different names such as calabar stone (English), la craie or argile (French), mabele (Lingala in Congo), nzu (Igbo of Nigeria), ndom (Efik/Ibibio Nigeria) eko (Bini/Edo Nigeria). It is also known as ebumba in Uganda, poto and ulo. In Ghana it is known as shilè.umcako in zulu (South Africa)
Location
Calabash chalk is found predominantly in Nigeria and other West African communities. Although this geophagic material is native to Africa, as a result of migration of West Africans to other nations, it can also be found in ethnic stores in the UK, Canada, Greece and the US. Calabash chalk is also eaten amongst women of African descent in the US state of Georgia.
Composition
Calabash chalk is a naturally occurring material composed of fossilized sea shells. However, it can be prepared artificially by combining clay, sand, wood ash and even salt. By molding and heating this mixture, the calabash chalk is obtained. It is available as a powder, a molded shape or a block.
There are different views concerning the components of calabash chalk, the consensus being that the major component is aluminum silicate hydroxide. This comes from the kaolin clay group, making Al2Si2O5(OH)4 a possible formula for calabash chalk. Calabash chalk is also known to have very high concentrations of lead. The European Union recommends (Commission Regulation, 2001) that the amount of lead in food should not exceed 1 mg/kg, however the amount of lead contained in calabash chalk has been reported (Codex Committee of Food |
https://en.wikipedia.org/wiki/List%20of%20shapes%20with%20known%20packing%20constant | The packing constant of a geometric body is the largest average density achieved by packing arrangements of congruent copies of the body. For most bodies the value of the packing constant is unknown. The following is a list of bodies in Euclidean spaces whose packing constant is known. Fejes Tóth proved that in the plane, a point symmetric body has a packing constant that is equal to its translative packing constant and its lattice packing constant. Therefore, any such body for which the lattice packing constant was previously known, such as any ellipse, consequently has a known packing constant. In addition to these bodies, the packing constants of hyperspheres in 8 and 24 dimensions are almost exactly known.
References
Packing problems
Discrete geometry
Mathematics-related lists |
https://en.wikipedia.org/wiki/Lists%20of%20fossiliferous%20stratigraphic%20units |
By location
Lists of fossiliferous stratigraphic units in Africa
List of fossiliferous stratigraphic units in Antarctica
Lists of fossiliferous stratigraphic units in Asia
List of fossiliferous stratigraphic units in the Caribbean
Lists of fossiliferous stratigraphic units in Europe
Lists of fossiliferous stratigraphic units in North America
Lists of fossiliferous stratigraphic units in Canada
Lists of fossiliferous stratigraphic units in the United States
Lists of
Lists of
By preserved taxon
List of dinosaur-bearing stratigraphic units
List of phytosaur-bearing stratigraphic units
List of plesiosaur-bearing stratigraphic units
List of pterosaur-bearing stratigraphic units
List of thalattosuchian-bearing stratigraphic units
See also
List of fossil sites
Stratigraphy
fossiliferous stratigraphic
Fossiliferous stratigraphic |
https://en.wikipedia.org/wiki/Ranging%20rod | A ranging rod (or range rod) is a surveying instrument used for marking the position of stations, and for sightings of those stations, as well as for ranging straight lines. Initially these were made of light, thin and straight bamboo, or of well seasoned wood such as teak, pine or deodar. They were shod with iron at the bottom and surmounted with a flag about 250 mm square in size. Nowadays they are made of wood, metal or fibreglass. The rods are usually about 30 mm in diameter and 2 m or 3 m long, painted with alternating bands, such as red and white, red and yellow, or black and white, in lengths of 200 mm (i.e. one link length of metric chain), 500 mm, or one foot. These colours are used so that the rod can be properly sighted in case of long distance or bad weather. Ranging rods of greater length, e.g. 3 to 6 m, are called ranging or range poles, and are used for very long survey lines. Another type of ranging rod is known as an offset rod, which has no flag at the top. It is used for measuring small offsets from the survey line when the work is of an ordinary nature.
Notes
When the ranging rods are limited, thin sticks 400 mm to 1 m length with white papers in the cuts at tops can serve their purpose. Such sticks are pointed at the bottom and are cut from wood. These are called as whites.
See also
Level staff
Tape (surveying)
Road curve
Survey camp
References
Surveying instruments
Civil engineering |
https://en.wikipedia.org/wiki/Set%20constraint | In mathematics and theoretical computer science, a set constraint is an equation or an inequation between sets of terms.
Similar to systems of (in)equations between numbers, methods are studied for solving systems of set constraints.
Different approaches admit different operators (like "∪", "∩", "\", and function application) on sets and different (in)equation relations (like "=", "⊆", and "⊈") between set expressions.
Systems of set constraints are useful to describe (in particular infinite) sets of ground terms.
They arise in program analysis, abstract interpretation, and type inference.
Relation to regular tree grammars
Each regular tree grammar can be systematically transformed into a system of set inclusions such that its minimal solution corresponds to the tree language of the grammar.
For example, the grammar (terminal and nonterminal symbols indicated by lower and upper case initials, respectively) with the rules
{|
|-
| BoolG || → false
|-
| BoolG || → true
|-
| BListG || → nil
|-
| BListG || → cons(BoolG,BListG)
|-
| BList1G || → cons(true,BListG)
|-
| BList1G || → cons(false,BList1G)
|}
is transformed to the set inclusion system (constants and variables indicated by lower and upper case initials, respectively):
{|
|-
| BoolS || ⊇ false
|-
| BoolS || ⊇ true
|-
| BListS || ⊇ nil
|-
| BListS || ⊇ cons(BoolS,BListS)
|-
| BList1S || ⊇ cons(true,BListS)
|-
| BList1S || ⊇ cons(false,BList1S)
|}
This system has a minimal solution, viz. ("L(N)" denoting the tree language corresponding to the nonterminal N in the above tree grammar):
{|
|-
| BoolS || = L(BoolG) || = { false, true }
|-
| BListS || = L(BListG) || = { nil, cons(false,nil), cons(true,nil), cons(false,cons(false,nil)), ... }
|-
| BList1S || = L(BList1G) || = { nil, cons(true,nil), cons(true,cons(false,nil)),... }
|}
The maximal solution of the system is trivial; it assigns the set of all terms to every variable.
Literature
Literature on negative constraints
Notes
Formal languages |
https://en.wikipedia.org/wiki/Numbeo | Numbeo is a Serbian crowd-sourced online database of perceived consumer prices, real property prices, and quality of life metrics. The website was founded in April 2009 by former Google employee Mladen Adamović, to enable users to share and compare information about the cost of living between countries and cities. Since 2012, the website has been operated by NUMBEO DOO Beograd-Palilula, a Serbian private limited company run by Adamović. According to Adamović, the website earns money through advertising and the sale of subscriptions to its API.
Numbeo's crowd-sourced data can be inserted or altered by anyone accessing the website, and is not peer-reviewed. Data is also manually gathered by the operator, from sources such as company and governmental websites, which is done in half-year intervals; it is then combined with user-generated data by giving it extra weight in the final score calculation, according to the company. As of 2017, it was the largest database of user generated data about cities in the world. As of 2020, this possibly applied to (user generated) data on housing prices as well. The quality of life index is a combination of eight sub-indexes: purchasing power, safety, healthcare, cost of living, property price to income ratio, traffic commute time, pollution, and climate.
The website's "Crime Index", intended to serve as an overall crime level estimate, is compiled from answers to user surveys, which have been processed by a Java-programmed backend to produce country- or city-level ratings on a 100-point scale, with higher values indicating worse crime. There is also a "Safety Index", with higher scores indicating a safer city. Numbeo's data points on crime have been criticized by academics and by the media as unreliable and, at times, misleading.
In 2017, a Swedish man manipulated the crime stats of the Lund, Sweden by repeatedly submitting negative ratings in this category, at a time when the relevant data set was very small. In less than a day, |
https://en.wikipedia.org/wiki/Size | Size in general is the magnitude or dimensions of a thing. More specifically, geometrical size (or spatial size) can refer to three geometrical measures: length, area, or volume. Length can be generalized to other linear dimensions (width, height, diameter, perimeter).
Size can also be measured in terms of mass, especially when assuming a density range.
In mathematical terms, "size is a concept abstracted from the process of measuring by comparing a longer to a shorter". Size is determined by the process of comparing or measuring objects, which results in the determination of the magnitude of a quantity, such as length or mass, relative to a unit of measurement. Such a magnitude is usually expressed as a numerical value of units on a previously established spatial scale, such as meters or inches.
The sizes with which humans tend to be most familiar are body dimensions (measures of anthropometry), which include measures such as human height and human body weight. These measures can, in the aggregate, allow the generation of commercially useful distributions of products that accommodate expected body sizes, as with the creation of clothing sizes and shoe sizes, and with the standardization of door frame dimensions, ceiling heights, and bed sizes. The human experience of size can lead to a psychological tendency towards size bias, wherein the relative importance or perceived complexity of organisms and other objects is judged based on their size relative to humans, and particularly whether this size makes them easy to observe without aid.
Human perception
Humans most frequently perceive the size of objects through visual cues. One common means of perceiving size is to compare the size of a newly observed object with the size of a familiar object whose size is already known. Binocular vision gives humans the capacity for depth perception, which can be used to judge which of several objects is closer, and by how much, which allows for some estimation of the size of t |
https://en.wikipedia.org/wiki/Cytometry%20Part%20A | Cytometry Part A is a peer-reviewed scientific journal covering all aspects of the study of cytometry that was established in 1980. It is the official journal of the International Society for Advancement of Cytometry.
Cytometry Part A focuses on molecular analysis of cellular systems as well as cell-based spectroscopic analyses and associated bioinformatics/computational methodologies.
Brian Mayall was the journal's founding editor-in-chief until 1998. Jan Visser and Charles Goolsby subsequently succeeded Brian Mayall in this position. Attila Tarnok has served as the Journal's editor-in-chief since 2007.
This journal was formerly known as Cytometry and first published in July 1980 with . It has been published with since 2003. Cytometry Part A is associated with Cytometry Part B, .
The journal is abstracted and indexed in:
BIOSIS Previews
Current Contents
MEDLINE/PubMed
Science Citation Index Expanded
Scopus
According to the Journal Citation Reports, the journal has a 2020 impact factor of 4.355.
References
Flow cytometry
Wiley (publisher) academic journals
Academic journals established in 1980 |
https://en.wikipedia.org/wiki/Lambda%20architecture | Lambda architecture is a data-processing architecture designed to handle massive quantities of data by taking advantage of both batch and stream-processing methods. This approach to architecture attempts to balance latency, throughput, and fault-tolerance by using batch processing to provide comprehensive and accurate views of batch data, while simultaneously using real-time stream processing to provide views of online data. The two view outputs may be joined before presentation. The rise of lambda architecture is correlated with the growth of big data, real-time analytics, and the drive to mitigate the latencies of map-reduce.
Lambda architecture depends on a data model with an append-only, immutable data source that serves as a system of record. It is intended for ingesting and processing timestamped events that are appended to existing events rather than overwriting them. State is determined from the natural time-based ordering of the data.
Overview
Lambda architecture describes a system consisting of three layers: batch processing, speed (or real-time) processing, and a serving layer for responding to queries. The processing layers ingest from an immutable master copy of the entire data set. This paradigm was first described by Nathan Marz in a blog post titled "How to beat the CAP theorem" in which he originally termed it the "batch/realtime architecture".
Batch layer
The batch layer precomputes results using a distributed processing system that can handle very large quantities of data. The batch layer aims at perfect accuracy by being able to process all available data when generating views. This means it can fix any errors by recomputing based on the complete data set, then updating existing views. Output is typically stored in a read-only database, with updates completely replacing existing precomputed views.
By 2014, Apache Hadoop was estimated to be a leading batch-processing system. Later, other, relational databases like Snowflake, Redshift, Synapse |
https://en.wikipedia.org/wiki/16%2C807 | 16807 is the natural number following 16806 and preceding 16808.
In mathematics
As a number of the form nn − 2 (16807 = 75), it can be applied in Cayley's formula to count the number of trees with seven labeled nodes.
In other fields
Several authors have suggested a Lehmer random number generator:
References
External links
16807 : facts & properties
16807 |
https://en.wikipedia.org/wiki/Sony%20Digital%20Paper | Sony Digital Paper is a line of tablet-size E ink devices by Sony, aimed at business professionals to read and edit digital documents.
DPT-S1
The Sony DPT-S1 is a 13.3-inch (approaching A4) E ink e-reader by Sony, aimed at professional business users. The DPT-S1 Digital Paper can display only PDF files at their native size and lacks the ability to display any other e-book formats. The reader has been criticized for being too expensive for most consumers, with an initial price of US$1,100, falling to $700 at its end. The reader is lightweight and has low power consumption, a Wi-Fi connection, and a stylus for making notes or highlights.
The DPT-S1 was released in Japan on December 3, 2013 and launched elsewhere in 2014. Sony announced the discontinuation of the DPT-S1 in late 2016.
Specifications
The 13.3-inch e-Ink Mobius electronic paper screen has a resolution of pixels, with a capacitive touchscreen. The device has an ARM Cortex-A8 at 1 GHz microprocessor. It was built on a SoC circuit made by Freescale. The amount of RAM was not published anywhere. Its internal storage, 4 GB, is shared between system and user; however, it is possible to expand the storage with a microSD card. It weighs 358 g (0.8 pounds) with a thickness of 6.8 mm. Novel to the DPT-S1 was the ability to interface with specific corporate networks by adding encryption, thus allowing legal professionals to make use of it in their workflow by integrating handwritten annotations into PDFs that could propagate when copied.
DPT-RP1
The Digital Paper DPT-RP1 was announced in April 2017. It features a 13.3-inch screen.
DPT-CP1
The DPT-CP1 from 2018 had a smaller 10.3-inch screen.
DPT-RP2
In 2023, Sony introduced the DPT-RP2.
See also
Comparison of e-book readers
Comparison of tablet computers
References
External links
Official site
Sony 13-inch (DPT-S1) Digital Paper Review | youtube.com video | 16:51 | published 8 August 2014
Sony hardware
Electronic paper technology |
https://en.wikipedia.org/wiki/Einstein%20problem | In plane geometry, the einstein problem asks about the existence of a single prototile that by itself forms an aperiodic set of prototiles; that is, a shape that can tessellate space but only in a nonperiodic way. Such a shape is called an einstein, a word play on ein Stein, German for "one stone". Several variants of the problem, depending on the particular definitions of nonperiodicity and the specifications of what sets may qualify as tiles and what types of matching rules are permitted, were solved beginning in the 1990s. The strictest version of the problem was solved in 2023 (the initial discovery was in November 2022, with a preprint published in March 2023), pending peer review. The einstein problem can be seen as a natural extension of the second part of Hilbert's eighteenth problem, which asks for a single polyhedron that tiles Euclidean 3-space, but such that no tessellation by this polyhedron is isohedral. Such anisohedral tiles were found by Karl Reinhardt in 1928, but these anisohedral tiles all tile space periodically.
Proposed solutions
In 1988, Peter Schmitt discovered a single aperiodic prototile in three-dimensional Euclidean space. While no tiling by this prototile admits a translation as a symmetry, some have a screw symmetry. The screw operation involves a combination of a translation and a rotation through an irrational multiple of π, so no number of repeated operations ever yield a pure translation. This construction was subsequently extended by John Horton Conway and Ludwig Danzer to a convex aperiodic prototile, the Schmitt–Conway–Danzer tile. The presence of the screw symmetry resulted in a reevaluation of the requirements for non-periodicity. Chaim Goodman-Strauss suggested that a tiling be considered strongly aperiodic if it admits no infinite cyclic group of Euclidean motions as symmetries, and that only tile sets which enforce strong aperiodicity be called strongly aperiodic, while other sets are to be called weakly aperiodic.
In 19 |
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