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2,980 | 1 | Knowing What to Imitate and Knowing When You Succeed If we are to build robots that can imitate the actions of a human instructor, the robotics community must address a variety of issues. In this paper, we examine two of these issues. First, how does the robot know which things it should imitate? Second, how does the robot know when its actions are an adequate imitation of the original? We further describe an on-going research effort to implement systems for a humanoid robot that address these issues. 1 Introduction Humans (and other animals) acquire new skills from social interactions with others through direct tutelage, observational conditioning, goal emulation, imitation, and other methods (Galef 1988). These social learning skills provide a powerful mechanism for children to acquire skills and knowledge from their parents, other adults, and other children. In particular, imitation is an extremely powerful mechanism for social learning which has received a great deal of interest from researchers in the fields of animal behavior... | [
757,
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] | Validation |
2,981 | 3 | Query Rewriting using Semistructured Views We address the problem of query rewriting for MSL, a semistructured language developed at Stanford in the TSIMMIS project for information integration. We develop and present an algorithm that, given a semistructured query q and a set of semistructured views V, finds rewriting queries, i.e., queries that access the views and produce the same result as q. Our algorithm is based on appropriately generalizing containment mappings, the chase, and unification -- techniques which were developed for structured, relational data. At the same time we develop an algorithm for equivalence checking of MSL queries. We show that the rewriting algorithm is sound and complete, i.e., it always finds every conjunctive MSL rewriting query of q, and we discuss its complexity. We currently incorporate the algorithm in the TSIMMIS system. 1 Introduction Recently, many semistructured data models, query and view definition languages have been proposed [GM + 97, MAG + 97, BDHS96, AV97a, MM97, KS95, PGMU96,... | [
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2,982 | 0 | ABC - An Intelligent Robocup Agent This paper will cover the basics of our virtual soccer team, ABC (Aiken, Benzacar, Cocosco) . It provides an overview of the agent's architecture, and in-depth explanation of its various modules. The agent's approach to achieving intelligent behavior, as contrasted with other approaches, is discussed. I. Introduction The international RoboCup competition is held yearly and pits teams of simulated soccer-playing agents against each other. The simulated environment in which the agents interact is designed to reproduce the challenges associated with an embodied agent: the sensory information provided to each agent is incomplete, noisy, and sporadic. With this imperfect data as a base, the agents are challenged to behave as a cohesive team in attempting to win their matches. This paper discusses the design and implementation of an Artificially Intelligent RoboCup agent, ABC. Its overall design is modeled after the architecture used by the winning team of the 1997 RoboCup competition, as ... | [
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2,983 | 2 | Internet Agents for Telemedicine Services Telemedicine can be viewed as the telematic support for collaboration among distant medical professionals, which cooperate on shared resources of various kind. In light of this, attention to telematics and informatics concepts particularly oriented towards collaboration should be paid: in particular, the recently appeared agent paradigm seems suitable for the analysis, design and development of telemedicine services because of its committment to intercommunication and sharing of resources. The present paper is aimed at introducing the agent paradigm, from the theoretical basis up to the technological issues, and at describing an agent-based approach to telemedicine, specifically applied to telepathology applications. The described system is based on an agent-based tool (JAMES), namely an agent model and template implemented using Java, which has been used to implement a prototype multipurpose telepathology application based on a federated agency architecture. | [
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2,984 | 2 | The PageRank Citation Ranking: Bringing Order to the Web The importance of a Web page is an inherently subjective matter, which depends on the readers interests, knowledge and attitudes. But there is still much that can be said objectively about the relative importance of Web pages. This paper describes PageRank, a method for rating Web pages objectively and mechanically, effectively measuring the human interest and attention devoted to them. We compare PageRank to an idealized random Web surfer. We show how to efficiently compute PageRank for large numbers of pages. And, we show how to apply PageRank to search and to user navigation. | [
7,
298,
333,
477,
538,
1069,
1959,
2106,
2454,
2503,
2545,
3131
] | Validation |
2,985 | 0 | An Agent-Based Approach to Distributed Simulation, Distributed Prototyping and Software Integration Due to nowadays huge availability of data and software, a software developer must be able not only to invent good algorithms and implement them efficiently, but also to assemble existing components to create, timely and economically, a new application. Prototyping is a software engineering paradigm particularly suitable for the compositional approach to software development. A working prototype embedding the heterogeneous software which will be used in the final application proves useful for at least two reasons: ffl the prototype is definitely closer to the final application; ffl the re-usability of the legacy software can be evaluated before the final application is built. The distribution of the software to be integrated within the prototype must be taken into account, as well as the distribution of the prototype execution. This would help to gain in efficiency and closeness to the final application. The aim of this thesis is to exploit the "multi-agent system" abstracti... | [
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2,986 | 1 | Learning to Predict Rare Events in Event Sequences Learning to predict rare events from sequences of events with categorical features is an important, real-world, problem that existing statistical and machine learning methods are not well suited to solve. This paper describes timeweaver, a genetic algorithm based machine learning system that predicts rare events by identifying predictive temporal and sequential patterns. Timeweaver is applied to the task of predicting telecommunication equipment failures from 110,000 alarm messages and is shown to outperform existing learning methods. Introduction An event sequence is a sequence of timestamped observations, each described by a fixed set of features. In this paper we focus on the problem of predicting rare events from sequences of events which contain categorical (non-numerical) features. Predicting telecommunication equipment failures from alarm messages is one important problem which has these characteristics. For AT&T, where most traffic is handled by 4ESS switches, the specific ... | [
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] | Train |
2,987 | 4 | ATLAS: A generic software platform for speech technology based applications ATLAS is a Java software library that provides a framework for building multilingual and multi-modal applications, especially dialogue systems, on top of speech technology components. The design is based on a layered system model, where ATLAS sits as a middleware between an application-dependent layer and the speech technology components and implements much of application-independent functionality in the system. ATLAS is itself layered with interfaces to speech technology components at the bottom and self-contained dialogue components at the top. The layered design is both efficient and flexible and is suitable for a research environment. The framework also provides support for applicationdependent layers through a structure of an application with sessions interacting with users through terminals. The terminal concept supports creating audio deviceindependent applications that run transparently in both telephone and desktop environments. Several speech technology components are available for use with the ATLAS framework, including text-to-speech, speech recognition and speaker verification systems. Four applications that use ATLAS have so far been developed within student and research projects at the Centre for Speech Technology (CTT), including a speech controlled telephone banking system (CTT-bank) and an automated entrance receptionist (PER). 1. | [
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2,988 | 4 | Close Encounters: Supporting Mobile Collaboration through Interchange of User Profiles . This paper introduces the notion of profile-based cooperation as a way to support awareness and informal communication between mobile users during chance encounters. We describe the design of Proem, a wearable system for profile-based cooperation that enables users to publish and exchange personal profile information during physical encounters. The Proem system is used to initiate contact between individuals by identifying mutual interests or common friends. In contrast to most previous research that concentrates on collaboration in well-defined and closed user groups, Proem supports informal communication between individuals who have never met before and who don't know each other. We illustrate the benefits of profile-based cooperation by describing several usage scenarios for the Proem system. 1 Introduction During the course of a day we encounter and meet a large number of people, some of whom we know personally and some of whom we never met before. In everyday languag... | [
269,
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2008,
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2,989 | 2 | Clustering Hypertext With Applications To Web Searching : Clustering separates unrelated documents and groups related documents, and is useful for discrimination, disambiguation, summarization, organization, and navigation of unstructured collections of hypertext documents. We propose a novel clustering algorithm that clusters hypertext documents using words (contained in the document), out-links (from the document) , and in-links (to the document). The algorithm automatically determines the relative importance of words, out-links, and in-links for a given collection of hypertext documents. We annotate each cluster using six information nuggets: summary, breakthrough, review, keywords, citation, and reference. These nuggets constitute high-quality information resources that are representatives of the content of the clusters, and are extremely effective in compactly summarizing and navigating the collection of hypertext documents. We employ web searching as an application to illustrate our results. Keywords: cluster annotation, feature comb... | [
488,
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2,990 | 2 | Ontology-Based Integration of Information - A Survey of Existing Approaches We review the use on ontologies for the integration of heterogeneous information sources. Based on an in-depth evaluation of existing approaches to this problem we discuss how ontologies are used to support the integration task. We evaluate and compare the languages used to represent the ontologies and the use of mappings between ontologies as well as to connect ontologies with information sources. We also ask for ontology engineering methods and tools used to develop ontologies for information integration. Based on the results of our analysis we summarize the state of the art in ontology-based information integration and name areas of further research activities. 1 Motivation The so-called information society demands for complete access to available information, which is often heterogeneous and distributed. In order to establish efficient information sharing, many technical problems have to be solved. First, a suitable information source must be located that might conta... | [
356,
454,
642,
803,
1238,
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2,991 | 0 | Meaning for Observers and Agents Claude Shannon formalized the notion of information transmission rate and capacity for pre-existing channels. Wittgenstein in his later work insisted that linguistic meaning be defined in terms of use in language games. C. S. Peirce, the father of semiotics, realized the importance of sign, signified, and interpretant in processes of semiosis. In particular, the connection between sign and signified does not take place in a platonic vacuum but is situated, embodied, embedded, and must be mediated by an interpretant. We introduce a rigorous mathematical notion of meaning, as (1) agent- and observer- perceptible information in interaction games between an agent and its environment or between an agent and other agents, that is (2) useful for satisfying homeostatic and other drives, needs, goals or intentions. With this framework it is possible to address issues of sensor- and actuator- design, origins, evolution, and maintenance for biological and artificial systems. Moreover, correspondences between channels of meaning are exploited by biological entities in predicting the behavior or reading the intent of others, as in predator-prey and social interaction. Social learning, imitation, communication of experience also develop and can be developed on this substrate of shared meaning. | [
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2,992 | 0 | Animated Agents for Procedural Training in Virtual Reality: Perception, Cognition, and Motor Control This paper describes Steve, an animated agent that helps students learn to perform physical, procedural tasks. The student and Steve cohabit a three-dimensional, simulated mock-up of the student's work environment. Steve can demonstrate how to perform tasks and can also monitor students while they practice tasks, providing assistance when needed. This paper describes Steve's architecture in detail, including perception, cognition, and motor control. The perception module monitors the state of the virtual world, maintains a coherent representation of it, and provides this information to the cognition and motor control modules. The cognition module interprets its perceptual input, chooses appropriate goals, constructs and executes plans to achieve those goals, and sends out motor commands. The motor control module implements these motor commands, controlling Steve's voice, locomotion, gaze, and gestures, and allowing Steve to manipulate objects in the virtual world. 1 Introduction To ma... | [
109,
569,
674,
1162,
1723,
2094,
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2,993 | 3 | Cost-Based Optimization of Decision Support Queries using Transient-Views Next generation decision support applications, besides being capable of processing huge amounts of data, require the ability to integrate and reason over data from multiple, heterogeneous data sources. Often, these data sources differ in a variety of aspects such as their data models, the query languages they support, and their network protocols. Also, typically they are spread over a wide geographical area. The cost of processing decision support queries in such a setting is quite high. However, processing these queries often involves redundancies such as repeated access of same data source and multiple execution of similar processing sequences. Minimizing these redundancies would significantly reduce the query processing cost. In this paper, we (1) propose an architecture for processing complex decision support queries involving multiple, heterogeneous data sources | [
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2,994 | 0 | On using degrees of belief in BDI agents : The past few years have seen a rise in the popularity of the use of mentalistic attitudes such as beliefs, desires and intentions to describe intelligent agents. Many of the models which formalise such attitudes do not admit degrees of belief, desire and intention. We see this as an understandable simplification, but as a simplification which means that the resulting systems cannot take account of much of the useful information which helps to guide human reasoning about the world. This paper starts to develop a more sophisticated system based upon an existing formal model of these mental attributes. 1 Introduction In the past few years there has been a lot of attention given to building formal models of autonomous software agents; pieces of software which operate to some extent independently of human intervention and which therefore may be considered to have their own goals and the ability to determine how to achieve those goals. Many of these formal models are based on the use of ... | [
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2,995 | 2 | Persona: A Contextualized and Personalized Web Search Recent advances in graph-based search techniques derived from Kleinberg's work [1] have been impressive. This paper further improves the graph-based search algo- rithm in two dimensions. Firstly, variants of Kleinberg's techniques do not take into account the semantics of the query string nor of the nodes being searched. As a result, polysemy of query words cannot be resolved. This paper presents an interactive query scheme utilizing the simple web ontology provided by the Open Directory Project to resolve meanings of a user query. Secondly, we extend a recently proposed personalized version of the Kleinberg algorithm [3]. Simulation results are presented to illustrate the sensitivity of our technique. We outline the implementation of our algorithm in the Persona personalized web search system. | [
471,
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] | Validation |
2,996 | 4 | The Shopping Jacket: Wearable Computing for the Consumer . As part of the Bristol Wearable Computing Initiative we are exploring location sensing systems suitable for use with Wearable Computing. In this paper we present our findings, and in particular a wearable application - the 'Shopping Jacket' - which relies on a minimal infrastructure to be effective. We use two positioning devices, 'Pingers' and GPS. The Pinger is used to signal the presence of a shop, and to indicate the type of shop and it's website. The GPS is used to disambiguate which branch of a high street chain we are passing. The wearable uses this information to determine whether the wearer needs to be alerted that they are passing an interesting shop, or to direct the wearer around a shopping mall. The shopping jacket integrates a wearable CardPC; GPS and Pinger receivers; a near-field radio link; hand-held display; GSM data telephone; and a speech interface into a conventional sports blazer. Keywords - wearable computer, location sensing, GPS, pinger, shoppin... | [
21,
66,
172,
468,
2617,
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] | Test |
2,997 | 1 | From Implicit Skills to Explicit Knowledge: A Bottom-Up Model of Skill Learning This paper presents a skill learning model CLARION. Different from existing models of mostly high-level skill learning that use a top-down approach (that is, turning declarative knowledge into procedural knowledge through practice), we adopt a bottom-up approach toward low-level skill learning, where procedural knowledge develops first and declarative knowledge develops later. Our model is formed by integrating connectionist, reinforcement, and symbolic learning methods to perform on-line reactive learning. It adopts a two-level dual-representation framework (Sun, 1995), with a combination of localist and distributed representation. We compare the model with human data in a minefield navigation task, demonstrating some match between the model and human data in several respects. | [
758,
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] | Train |
2,998 | 0 | Cyber-Atvs: Dynamic And Distributed Reconnaissance And Surveilllance Using All Terrain Ugvs This paper describes our current effort to develop robotic vehicles for tactical distributed surveillance. Our research is focused on multi-agent collaboration, reconfigurable systems, efficient perception and sensor fusion, distributed command and control, and task decomposition. In particular, this paper describes the main features and capabilities of our All Terrain Vehicles (ATVs), concentrating on their autonomous navigation capabilities. | [
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2,999 | 5 | Map Learning and High-Speed Navigation in RHINO This chapter surveys basic methods for learning maps and high speed autonomous navigation for indoor mobile robots. The methods have been developed in our lab over the past few years, and most of them have been tested thoroughly in various indoor environments. The chapter is targeted towards researchers and engineers who attempt to build reliable mobile robot navigation software. | [
5,
793,
809,
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3,000 | 0 | An Agent-based Petri Net Model with Application to Seller/Buyer Design in Electronic Commerce Agents are becoming one of the most important topics in distributed and autonomous decentralized systems (ADS), and there are increasing attempts to use agent technologies to develop software systems in electronic commerce. Such systems are complex and there is a pressing need for system modeling techniques to support reliable, maintainable and extensible design. G-Nets are a type of Petri net defined to support modeling of a system as a set of independent and loosely-coupled modules. In this paper, we first introduce an extension of G-Net, agent-based G-Net, as a generic model for agent design. Then new communication mechanisms are introduced to support asynchronous message passing among agents. To illustrate our formal modeling technique is effective for agent modeling in electronic commerce, a pricenegotiation protocol example between buyers and sellers is provided. Finally, by analyzing an ordinary Petri net reduced from our agent-based G-Net models, we conclude that our agent-based G-Net models are L3-live, concurrent and effective for agent communications. 1. | [
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3,001 | 0 | Essex Wizards'99 Team Description : This paper describes the Essex Wizards team participated in the RoboCup'99 simulator league. It is mainly concentrated on a multi-threaded implementation of simulated soccer agents to achieve real-time performance. Simulated robot agents work at three distinct phases: sensing, thinking and acting. POSIX threads are adopted to implement them concurrently. The issues of decision-making and co-operation are also addressed. 1. Introduction In the RoboCup simulator environment, the response time of a soccer agent becomes significantly important since the soccer server operates with 100ms cycles for executing actions and 150ms cycles for providing sensory data [12]. Moreover, auditory sensory data can be received at random intervals. It is vital that each agent has bounded response times. If an action is not generated within 100ms, then the agent will stay idle for that cycle and enemy agents that did act might gain an advantage. On the other hand, if more than one action is generat... | [
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3,002 | 5 | Exploring Dynamic Bayesian Belief Networks for Intelligent Fault Management Systems Systems that are subject to uncertainty in their behaviour are often modelled by Bayesian Belief Networks (BBNs). These are probabilistic models of the system in which the independence relations between the variables of interest are represented explicitly. A directed graph is used, in which two nodes are connected by an edge if one is a 'direct cause' of the other. However the Bayesian paradigm does not provide any direct means for modelling dynamic systems. There has been a considerable amount of research effort in recent years to address this. This paper reviews these approaches and proposes a new dynamic extension to the BBN. This paper proceeds to discuss fault management of complex telecommunications and how the dynamic bayesian models can assist in the prediction of faults. Keywords: dynamic bayesian belief networks, telecommunication networks, fault management, intelligent systems. 1 | [
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3,003 | 2 | Item-based Collaborative Filtering Recommendation Algorithms Recommender systems apply knowledge discovery techniques to the problem of making personalized recommendations for information, products or services during a live interaction. These systems, especially the k-nearest neighbor collaborative filtering based ones, are achieving widespread success on the Web. The tremendous growth in the amount of available information and the number of visitors to Web sites in recent years poses some key challenges for recommender systems. These are: producing high quality recommendations, performing many recommendations per second for millions of users and items and achieving high coverage in the face of data sparsity. In traditional collaborative filtering systems the amount of work increases with the number of participants in the system. New recommender system technologies are needed that can quickly produce high quality recommendations, even for very large-scale problems. To address these issues we have explored item-based collaborative filtering techniques. Itembased techniques first analyze the user-item matrix to identify relationships between different items, and then use these relationships to indirectly compute recommendations for users. In this paper we analyze different item-based recommendation generation algorithms. We look into different techniques for computing item-item similarities (e.g., item-item correlation vs. cosine similarities between item vectors) and different techniques for obtaining recommendations from them (e.g., weighted sum vs. regression model). Finally, we experimentally evaluate our results and compare them to the basic k-nearest neighbor approach. Our experiments suggest that item-based algorithms provide dramatically better performance than user-based algorithms, while at the same time providing better quality than the best available user-based algorithms. 1 | [
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3,004 | 2 | Probability Based Clustering for Document and User Properties . Information Retrieval systems can be improved by exploiting context information such as user and document features. This article presents a model based on overlapping probabilistic or fuzzy clusters for such features. The model is applied within a fusion method which linearly combines several retrieval systems. The fusion is based on weights for the different retrieval systems which are learned by exploiting relevance feedback information. This calculation can be improved by maintaining a model for each document and user cluster. That way, the optimal retrieval system for each document or user type can be identified and applied. The extension presented in this article allows overlapping, probabilistic clusters of features to further refine the process. 1. | [
147,
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3,005 | 3 | Program Comprehension in Multi-Language Systems This paper presents an approach to program comprehension in multi-language systems. Such systems are characterized by a high amount of source codes in various languages for programming, database definition and job control. Coping with those systems requires the references crossing the language boundaries to be analysed. Using the EER/GRAL approach to graph-based conceptual modeling, models representing relevant aspects of single language are built and integrated into a common conceptual model. Since conceptual modeling focusses on specific problems, the integrated model presented here is especially tailored to multi-language aspects. Software systems are parsed and represented according to this conceptual model and queried by using a powerful graph query mechanism. This allows multi-language cross references to be easily retrieved. The multi-language conceptual model and the query facilities have been developed in cooperation with the maintenance programmers at an insurance company w... | [
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3,006 | 3 | Integrating Keyword Search into XML Query Processing Due to the popularity of the XML data format, several query languages for XML have been proposed, specially devised to handle data whose structure is unknown, loose, or absent. While these languages are rich enough to allow for querying the content and structure of an XML document, a varying or unknown structure can make formulating queries a very difficult task. We propose an extension to XML query languages that enables keyword search at the granularity of XML elements, that helps novice users formulate queries, and also yields new optimization opportunities for the query processor. We present an implementation of this extension on top of a commercial RDBMS; we then discuss implementation choices and performance results. Keywords XML query processing, full-text index 1 Introduction There is no doubt that XML is rapidly becoming one of the most important data formats. It is already used for scientific data (e.g., DNA sequences), in linguistics (e.g., the Treebank database at the U... | [
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3,007 | 3 | Solving a huge number of similar tasks: a combination of multi-task learning and a hierarchical Bayesian approach In this paper, we propose a machine-learning solution to problems consisting of many similar prediction tasks. Each of the individual tasks has a high risk of overfitting. We combine two types of knowledge transfer between tasks to reduce this risk: multi-task learning and hierarchical Bayesian modeling. Multitask learning is based on the assumption that there exist features typical to the task at hand. To find these features, we train a huge two-layered neural network. Each task has its own output, but shares the weights from the input to the hidden units with all other tasks. In this way a relatively large set of possible explanatory variables (the network inputs) is reduced to a smaller and easier to handle set of features (the hidden units). Given this set of features and after an appropriate scale transformation, we assume that the tasks are exchangeable. This assumption allows for a hierarchical Bayesian analysis in which the hyperparameters can be estimated from the data. Effect... | [
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3,008 | 0 | Modeling and Verifying Multi-Agent Behaviors Using Predicate Transition Nets In a multi-agent system, how agents accomplish a goal task is usually specified by multi-agent plans built from basic actions (e.g. operators) of which the agents are capable. A critical problem with such an approach is how can the designer make sure the plans are reliable. To tackle this problem, this paper presents a formal approach for modeling and analyzing multi-agent behaviors using Predicate/Transition (PrT) nets, a high-level formalism of Petri nets. We construct a multi-agent model by representing agent capabilities as transitions. To verify a multiagent PrT model, we adapt the planning graphs as a compact structure for the reachability analysis. We also demonstrate that, based on the PrT model, whether parallel actions specified in multi-agent plans can be executed in parallel and whether the plans guarantee the achievement of the goal can be verified by analyzing the dependency relations among the transitions. | [
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3,009 | 0 | Agents for Process Coherence in Virtual Enterprises SoCom # 1 "on time" Abstract SoCom # 2 "cheap" Buyer Seller Abstract SoCom # 3 Buyer Seller SoCom Manager Hoosier Inc. Register me as buyer and seller Register me as buyer and seller Play Seller in AbstractSoCom #1? Yes Valvano & Co. Hot Air Bros. 8 9 Concrete SoCom created 4 6 7 "high quality" = Roles = Agents Directory Agent_id Role derived 1 Figure 2. Instantiation of a concrete SoCom 68 March 1999/Vol. 42, No. 3 COMMUNICATIONS OF THE ACM Adopt role Need to initiate Ask SoCom manager Participate No No No No No No No Ye s Yes Ye s Yes Yes Yes Ye s Register SoCom manager suggests a socom Request to create SoCom Process request Stop Stop (undefined) Stop (Failure) Instantiate and announce Receipt of a request Request to register Condition evaluation OK? Find candidates Ask candidates All say yes? Agents decision making SoCom manager's decision making Because our agents are autonomous, we must e... | [
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3,010 | 0 | Learning to Notice: Adaptive Models of Human Operators Agent-based technologies have been used for a number of years to model human operators in complex simulated environments. The BDI agent framework has proven to be particularly suited to this sort of modelling, due to its "natural" composition of beliefs, goals and plans. However one of the weaknesses of the BDI agent model, and many other human operator models (agent-based or otherwise), is its inability to support agent learning. Human operators naturally adapt their behaviour over time, particularly to avoid repeating mistakes. This paper introduces an enhancement to the BDI framework which is based on a descriptive psychological model of decision making called "recognition-primed decision making." This enhancement allows the development of agents that adapt their behaviour in real-time, in the same manner as a person would, providing more realistic human operator models. | [
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3,011 | 0 | A Multiagent Approach for Electronic Travel Planning In the last years, the amount of information stored in Internet has grown exponentially. This article presents a new approach to cooperative problem solving that use the Web as a source of data. The architecture has been designed using two main Artificial Intelligence techniques: Multiagent System design, and problem solving (planning). Both are used to obtain a new architecture that dynamically obtains knowledge from Internet. The system uses two different types of agents: planning agents and web agents. Planning agents pay attention to the user's queries and solve his/her problems at a high level of abstraction; web agents fill in the details obtaining the required information from Internet. Different partial solutions given by the web agents while combined by the planning agent to obtain a detailed solution (or solutions) to the user queries. | [
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3,012 | 1 | Adaptive Combination of Behaviors in an Agent rchical structures [PS97]. often require specific manual preparations (the shape of the structure). . Factored representations [Sal00]. are not scalable, but restricted to a given environment (number of objects, size of environment...). 8/19 ECAI'02 # # # # # # 9/19 ECAI'02 # # # # # # Idea : Hypothesis: A complex behavior is often guided by a set of basic motivations (i.e. goals). Idea: Make use of basic behaviors associated with the basic motivations to recombine them in one complex behavior. agent O1 O3 10/19 ECAI'02 # # # # # # Scene decomposition: O2 agent O1 O2 O3 O2 O1 + =? . Perceived objects: O 1 , O 2 et O 3 . . Basic behaviors: avoid holes (b a , {#hole#}) push tiles (b p , {#hole#, #tile#}) . (behavior, config) pairs: (b a , 2 11/19 ECAI'02 # # # # # # Basic Behaviors: Example : }): behavior pushing tile O 1 in hole O 2 O2 O1 O3 A basic generic behavior b is defined by . a type of configuration {#T obj 1 | [
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3,013 | 1 | An Adaptive Penalty Approach for Constrained Genetic-Algorithm Optimization In this paper we describe a new adaptive penalty approach for handling constraints in genetic algorithm optimization problems. The idea is to start with a relatively small penalty coefficient and then increase it or decrease it on demand as the optimization progresses. Empirical results in several engineering design domains demonstrate the merit of the proposed approach. 1 Introduction Genetic Algorithms (GAs) (Goldberg 1989) are search algorithms that mimic the behavior of natural selection. GAs attempt to find the best solution to some problem (e.g., the maximum of a function) by generating a collection ("population ") of potential solutions ("individuals") to the problem. Through mutation and recombination (crossover) operations, better solutions are hopefully generated out of the current set of potential solutions. This process continues until an acceptably good solution is found. GAs have many advantages over other search techniques, including the ability to deal with qualitativ... | [] | Train |
3,014 | 0 | Connecting Planning And Acting Via Object-Specific Reasoning Instructions from a high-level planner are in general too abstract for a behavioral simulator to execute. In this dissertation I describe an intermediate reasoning system -- the Object-Specific Reasoner -- which bridges the gap between high-level task-actions and action directives of a behavioral system. It decomposes task-actions and derives parameter values for each action directive, thus enabling existing high-level planners to instruct synthetic agents with the same task-action commands that they currently produce. The Object-Specific Reasoner's architecture follows directly from the hypothesis that action representations are underspecified descriptions, and that objects in the same functional category are manipulated in similar ways. The action representation and the object representation are combined to complete the action interpretation, thereby grounding plans in action. The Object-Specific Reasoner provides evidence that a small number of object functional categories, organize... | [
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3,015 | 1 | Learning Behavioral Parameterization Using Spatio-Temporal Case-Based Reasoning This paper presents an approach to learning an optimal behavioral parameterization in the framework of a Case-Based Reasoning methodology for autonomous navigation tasks. It is based on our previous work on a behavior-based robotic system that also employed spario-temporal case-based reasoning [3] in the selection of behavioral parameters but was not capable of learning new parameterizations. The present method extends the case-based reasoning module by making it capable of learning new and optimizing the existing cases where each case is a set of behavioral parameters. The learning process can either be a separate training process or be part of the mission execution. In either case, the robot learns an optimal parameterization of its behavior for different environments it encounters. The goal of this research is not only to automatically optimize the performance of the robot but also to avoid the manual configuration of behavioral parameters and the initial configuration of a case library, both of which require the user to possess good knowledge of robot behavior and the performance of numerous experiments. The presented method was integrated within a hybrid robot architecture and evaluated in extensive computer simulations, showing a significant increase in the performance over a nonadaptive system and a performance comparable to a non-learning CBR system that uses a hand-coded case library. | [
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3,016 | 2 | The Web Graph: an Overview this paper, a study is made on a 200 millions vertices graph obtained from a crawl of the Web, and it appears that is is composed of four parts of equivalent sizes. See Figure 3. The first part is the largest strongly connected component of the graph (the second largest is much smaller), which composes the core of the well connected pages. The second part, called IN, is composed of those pages from which the core is reachable, but which are not reachable from the core. Conversly, the third part, called OUT, is the set of pages reachable from the core but from which the core is unreachable. Finally, the dendrites are the pages reachable from one of the three first parts, or from which one of the three first parts is reachable, but which belong to none of the previous parts. Only ten percent of the whole graph do not belong to one of these four parts which compose the bow-tie | [
471,
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] | Train |
3,017 | 5 | Playing Soccer with Legged Robots Sony has provided a remarkable platform for research and development in robotic agents, namely fully autonomous legged robots. In this paper, we describe our work using Sony's legged robots to participate at the RoboCup'98 legged robot demonstration and competition. Robotic soccer represents a very challenging environment for research into systems with multiple robots that need to achieve concrete objectives, particularly in the presence of an adversary. Furthermore RoboCup'98 offers an excellent opportunity for robot entertainment. We introduce the RoboCup context and briefly present Sony's legged robot. We developed a vision-based navigation and a Bayesian localization algorithm. Team strategy is achieved through pre-defined behaviors and learning by instruction. 1 Introduction Problem solving in complex domains necessarily involves multiple agents, dynamic environments, and the need for learning from feedback and previous experience. Robotic soccer is an example of one such complex... | [
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3,018 | 0 | Extreme Programming of Multi-Agent Systems The complexity of communication scenarios between agents make multi-agent systems difficult to build. Most of the existing Agent-Oriented Software Engineering methodologies face this complexity by guiding the developers through a rather waterfall-based process with a series of intermediate modeling artifacts. While these methodologies lead to executable prototypes relatively late and are expensive when requirements change, we explore a rather evolutionary approach with explicit support for change and rapid feedback. In particular, we apply Extreme Programming, a modern light-weight methodology from object-oriented software technology, for the design and implementation of multiagent systems. The only modeling artifacts that are being maintained in our approach are a process model with which domain experts and developers design and communicate agent application scenarios, and the executable agent source code including automated test cases. Our methodology has been successfully applied for the development of a prototypical multi-agent system for clinical information logistics. 1. | [
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3,019 | 1 | Feature selection using Expected Attainable Discrimination We propose expected attainable discrimination (EAD) as a measure to select discrete valued features for reliable discrimination between two classes of data. EAD is an average of the area under the ROC curves obtained when a simple histogram probability density model is trained and tested on many random partitions of a data set. EAD can be incorporated into various stepwise search methods to determine promising subsets of features, particularly when misclassification costs are difficult or impossible to specify. Experimental application to the problem of risk prediction in pregnancy is described. Keywords: Receiver operating characteristic (ROC); Area under the ROC curve; Feature selection; Risk prediction in pregnancy; Failure to progress. 1 Introduction Feature selection is a key step towards solving any practical classification problem (Kittler, 1975). Even though a Bayes classifier can never be improved by omission of features (Van Campenhout, 1982), there are compelling practical... | [
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3,020 | 0 | A Multi-Plane State Machine Agent Model This paper presents a framework for implementing collaborative network agents. Agents are assembled dynamically from components into a structure described by a multi-plane state machine model. This organization lends itself to an elegant implementations of remote control, collaboration, checkpointing and mobility, dening features of an agent system. It supports techniques, like agent surgery dicult to reproduce with other approaches. The reference implementation for our model, the Bond agent system, is distributed under an open source license and can be downloaded from http://bond.cs.purdue.edu. 1 Introduction The eld of agents is witnessing the convergence of researchers from several elds. Some see agents as a natural extension of the object-oriented programming paradigm, [14, 15]. One of the most popular books on articial intelligence reinterprets the whole eld in terms of agents [2]. Contemporary work on the theory of behavior provides the foundations for theoretical mo... | [
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3,021 | 5 | Spontaneous, Short-term Interaction with Mobile Robots major open research directions in mobile robotics. This paper considers a specific type of interaction: short-term and spontaneous interaction with crowds of people. Such patterns of interactions are found when service robots operate in public places, for example information kiosks, receptionists, tour-guide robots applications. We describe our approach to spontaneous short-term interaction: a robot designed to be a believable social agent. The approach has been implemented using a mobile robot with a motorized face as focal point for interaction, an architecture that suggests the robot has moods, and a method for learning how to interact with people. Our system was recently deployed at a Smithsonian museum in Washington, DC. During a two week period it interacted with thousands of people. The robot's interactive capabilities were essential for its high on-task performance, and thus its practical success. | [
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3,022 | 0 | A Plan Based Agent Architecture for Interpreting Natural Language Dialogue This paper describes a plan-based agent architecture for modeling NL cooperative dialogue; in particular, the paper focuses on the interpretation dialogue and explanation of its coherence by means of the recognition of the speakers' underlying intentions. The approach we propose makes it possible to analyze and explain in a uniform way several apparently unrelated linguistic phenomena, which have been often studied separately and treated via ad-hoc methods in the models of dialogue presented in the literature. Our model of linguistic interaction is based on the idea that dialogue can be seen as any other interaction among agents: therefore, domain-level and linguistic actions are treated in a similar way. Our agent architecture is based on a two-level representation of the knowledge about acting: at the metalevel, the Agent Modeling plans describe the recipes for plan formation and execution (they are a declarative representation of a reactive planner); at the object level, the domain ... | [
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3,023 | 1 | Evolving Detectors of 2D Patterns on a Simulated CAM-Brain Machine, an Evolvable Hardware Tool for Building a 75 Million Neuron Artificial Brain . This paper presents some simulation results of the evolution of 2D visual pattern recognizers to be implemented very shortly on real hardware, namely the "CAM-Brain Machine" (CBM), an FPGA based piece of evolvable hardware which implements a genetic algorithm (GA) to evolve a 3D cellular automata (CA) based neural network circuit module, of approximately 1,000 neurons, in about a second, i.e. a complete run of a GA, with 10,000s of circuit growths and performance evaluations. Up to 65,000 of these modules, each of which is evolved with a humanly specified function, can be downloaded into a large RAM space, and interconnected according to humanly specified artificial brain architectures. This RAM, containing an artificial brain with up to 75 million neurons, is then updated by the CBM at a rate of 130 billion CA cells per second. Such speeds will enable real time control of robots and hopefully the birth of a new research field that we call "brain building". The first su... | [
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3,024 | 3 | Querying Network Directories Hierarchically structured directories have recently proliferated with the growth of the Internet, and are being used to store not only address books and contact information for people, but also personal pro les, network resource information, and network and service policies. These systems provide a means for managing scale and heterogeneity, while allowing for conceptual unity and autonomy across multiple directory servers in the network, in a way far superior to what conventional relational or object-oriented databases o er. Yet, in deployed systems today, much of the data is modeled in an ad hoc manner, and many of the more sophisticated \queries " involve navigational access. In this paper, we develop the core of a formal data model for network directories, and propose a sequence of e ciently computable query languages with increasing expressive power. The directory data model can naturally represent rich forms of heterogeneity exhibited in the real world. Answers to queries expressible in our query languages can exhibit the same kinds of heterogeneity. We present external memory algorithms for the evaluation of queries posed in our directory query languages, and prove the e ciency of each algorithm in terms of its I/O complexity. Our data model and query languages share the exibility and utility of the recent proposals for semi-structured data models, while at the same time e ectively addressing the speci c needs of network directory applications, which we demonstrate by means of a representative real-life example. This work was done when the authors were at AT&T Labs{ | [
655,
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3,025 | 2 | Machine Learning and Knowledge Representation in the LaboUr Approach to User Modeling . In early user-adaptive systems, the use of knowledge representation methods for user modeling has often been the focus of research. In recent years, however, the application of machine learning techniques to control user-adapted interaction has become popular. In this paper, we present and compare adaptive systems that use either knowledge representation or machine learning for user modeling. Based on this comparison, several dimensions are identified that can be used to distinguish both approaches, but also to characterize user modeling systems in general. The LaboUr (Learning about the User) approach to user modeling is presented which attempts to take an ideal position in the resulting multi-dimensional space by combining machine learning and knowledge representation techniques. Finally, an implementation of LaboUr ideas into the information server ELFI is sketched. 1 Introduction While striving to achieve user-adapted interaction, user modeling researchers have often m... | [
676,
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] | Test |
3,026 | 1 | Learning Fuzzy Classification Rules from Data . Automatic design of fuzzy rule-based classification systems based on labeled data is considered. It is recognized that both classification performance and interpretability are of major importance and e#ort is made to keep the resulting rule bases small and comprehensible. An iterative approach for developing fuzzy classifiers is proposed. The initial model is derived from the data and subsequently, feature selection and rule base simplification are applied to reduce the model, and a GA is used for model tuning. An application to the Wine data classification problem is shown. 1 Introduction Rule-based expert systems are often applied to classification problems in fault detection, biology, medicinem etc. Fuzzy logic improves classification and decision support systems by allowing the use of overlapping class definitions and improves the interpretability of the results by providing more insight into the classifier structure and decision making process [13]. The automatic determination... | [
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3,027 | 2 | Improving Index Structures for Structured Document Retrieval Structured document retrieval has established itself as a new research area in the overlap between Database Systems and Information Retrieval. This work proposes a filtering technique, that can be added to already existing index structures of many structured document retrieval systems. This new technique takes the contextual structure information of query and document database into account and reduces the occurrence sets returned by the original index structure drastically. This improves the performance of query evaluation. A measure is introduced that allows to quantify the added value of the proposed index structure. Based on this measure a heuristic is presented that allows to include only valuable context information in the index structure. 1 Introduction With the growing importance of Information Retrieval in the presence of a vast amount of structured documents in formalisms like SGML ([ISO86]) or the future WWW language XML ([W3C99]), sophisticated and efficient indexing techn... | [
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3,028 | 2 | Eigentaste: A Constant Time Collaborative Filtering Algorithm Abstract. Eigentaste is a collaborative filtering algorithm that uses universal queries to elicit real-valued user ratings on a common set of items and applies principal component analysis (PCA) to the resulting dense subset of the ratings matrix. PCA facilitates dimensionality reduction for offline clustering of users and rapid computation of recommendations. For a database of n users, standard nearest-neighbor techniques require O(n) processing time to compute recommendations, whereas Eigentaste requires O(1) (constant) time. We compare Eigentaste to alternative algorithms using data from Jester, an online joke recommending system. Jester has collected approximately 2,500,000 ratings from 57,000 users. We use the Normalized Mean Absolute Error (NMAE) measure to compare performance of different algorithms. In the Appendix we use Uniform and Normal distribution models to derive analytic estimates of NMAE when predictions are random. On the Jester dataset, Eigentaste computes recommendations two orders of magnitude faster with no loss of accuracy. Jester is | [
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3,029 | 2 | An Autonomous Page Ranking Method for Metasearch Engines this paper, the topics are derived from the user's query; the reputation of each result page on the query topic is computed, and the value used to rank the result pages across all participating search engines, without biasing the ranking towards any of the sources | [
1838,
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3,030 | 0 | Desires and Defaults: A Framework for Planning with Inferred Goals This paper develops a formalism designed to integrate reasoning about desires with planning. The resulting logic, BDP, is capable of modeling a wide range of common-sense practical arguments, and can serve as a more general and flexible model for agent architectures. | [
1658
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3,031 | 2 | Visual Information Retrieval from Large Distributed On-line Repositories ion --- VIR systems differ in the level of abstraction in which content is indexed. For example, images may be indexed at various levels, such as at the feature-level (e.g., color, texture, and shape), object-level (e.g., moving foreground object), syntax-level (e.g., video shot), and semantic-level (e.g., image subject), and so forth. Most automatic VIR systems aim at lowlevel features, while the high-level indexes are usually generated manually. Interaction among different levels is an exciting but unsolved issue. . Generality --- VIR systems differ in their specificity of the domain of visual information. For example, customized feature sets can be developed to incorporate specific domain knowledge, such as those in medical and remote-sensing applications. Other, more general VIR systems aim at indexing unconstrained visual information such as that on the Internet. . Content Collection --- VIR systems differ in the methods in which new visual information is ad... | [
36,
224,
270,
1159,
1858,
2088,
2098,
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3,032 | 0 | The Cooperative Problem-Solving Process We present a model of cooperative problem solving that describes the process from its beginning, with some agent recognizing the potential for cooperation with respect to one of its goals, through to team action. Our approach is to characterize the mental states of the agents that lead them to solicit, and take part in, cooperative action. The model is formalized by expressing it as a theory in a quantified multi-modal logic. Keywords: Multi-agent systems, cooperation, modal logic, temporal logic. 1 Introduction Agents --- both human and artificial --- can engage in many and varied types of social interaction, ranging from altruistic cooperation through to open conflict. However, perhaps the paradigm example of social interaction is cooperative problem solving (CPS), in which a group of autonomous agents choose to work together to achieve a common goal. For example, we might find a group of people working together to move a heavy object, play a symphony, build a house, or write a jo... | [
1260,
1334,
1724,
1946
] | Validation |
3,033 | 2 | Towards Structural Logistic Regression: Combining Relational and Statistical Learning Inductive logic programming (ILP) techniques are useful for analyzing data in multi-table relational databases. Learned rules can potentially discover relationships that are not obvious in ``flattened'' data. Statistical learners, on the other hand, are generally not constructed to search relational data, they expect to be presented with a single table containing a set of feature candidates. However, statistical learners often yield more accurate models than the logical forms of ILP, and can better handle certain types of data, such as counts. We propose a new approach which integrates structure navigation from ILP with regression modeling. Our approach propositionalizes the first-order rules at each step of ILP's relational structure search, generating features for potential inclusion in a regression model. Ideally, feature generation by ILP and feature selection by stepwise regression should be integrated into a single loop. Preliminary results for scientific literature classification are presented using a relational form of the data extracted by ResearchIndex (formerly CiteSeer). We use FOIL and logistic regression as our ILP and statistical components (decoupled at this stage). Word counts and citation-based features learned with FOIL are modeled together by logistic regression. The combination often significantly improves performance when high precision classification is desired. | [
518,
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3,034 | 3 | Active Disks Several application and technology trends indicate that it might be both profitable and feasible to move computation closer to the data that it processes. In this paper, we evaluate Active Disk architectures which integrate significant processing power and memory into a disk drive and allow application-specific code to be downloaded and executed on the data that is being read from (written to) disk. The key idea is to offload bulk of the processing to the disk-resident processors and to use the host processor primarily for coordination, scheduling and combination of results from individual disks. To program Active Disks, we propose a stream-based programming model which allows disklets to be executed efficiently and safely. Simulation results for a suite of seven algorithms from three application domains (commercial data warehouses, image processing and satellite data processing) indicate that for these algorithms, Active Disks outperform conventional-disk architectures. 1 Introduction... | [
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3,035 | 2 | Intelligent Information Access in the Web: ML based User Modeling for high precision Meta-Search It is a well known fact that high precision search for documents concerning a certain topic in the World Wide Web (Www) is a tough problem. Index based search engines vary in recall (with a coverage of at most 30% of the web) and offer a very bad precision by (simple) keyword search. Meta search engines provide a specialised monolithic architecture for information extraction, and integration of heterogenous information resources which ensures a bigger recall and may yield a better precision. Few search engines (as, e. g., HuskySearch) employ intelligent techniques in order to increase precision. On the other hand, many personalized agents for web browsing are currently developed. It is a straightforward idea to incorporate the idea of user modeling with machine learning (Ml) methods into web search services. We propose an abstract prototype, OySTER, which makes use of machine learning based user modeling and which for reasons of robustness, performance and quality is realised as a mult... | [
759,
1053,
1290,
1847,
2393
] | Validation |
3,036 | 5 | On the Complexity of Terminological Reasoning TBoxes are an important component of knowledge representation systems based on description logics (DLs) since they allow for a natural representation of terminological knowledge. Largely due to a classical result given by Nebel [ 20 ] , complexity analyses for DLs have, until now, mostly focused on reasoning without (acyclic) TBoxes. In this paper, we concentrate on DLs, for which reasoning without TBoxes is PSpace-complete, and show that there exist logics for which the complexity of reasoning remains in PSpace if acyclic TBoxes are added and also logics for which the complexity increases. An example for a logic of the former type is ALC while examples for logics of the latter kind include ALC(D) and ALCF . This demonstrates that it is necessary to take TBoxes into account for complexity analyses. Furthermore, we show that reasoning with the description logic ALCRP(D) is NExpTime-complete regardless of whether TBoxes are admitted or not. 1 Introduction A core feature of description... | [
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] | Train |
3,037 | 2 | Web Search -- Your Way We describe a metasearch engine architecture, in use at NEC Research Institute, that allows users to provide preferences in the form of an information need category. This extra information is used to direct the search process, providing more valuable results than by considering only the query. Using our architecture, identical keyword queries may be sent to different search engines, and results may be scored differently for different users. | [
378,
1108,
1321,
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3,038 | 0 | Mental States Recognition from Communication Effective and useful communication requires the agents' being able to foresee the effects of their utterances over the addressee's mental state. However, referring to the classical Speech Act Theory, it seems to us that the idea of predicting such effects is rather optimistic since they are not really completely "a priori" foreseeable by the speaker. Along with some obvious main effects, there are other side effects which might be regarded as the result of some kind of plausible inference, particularly abduction, performed by the hearerhimself79 the received communication and over: - its own actual mental state (which can be differentfromen one expected by the speaker), - its image (may be incorrect and incomplete) ofthe81-24 's mental state. In this paper we explore the idea that if (and asfar17 it is possible: 1. to formalize in a declarative manner the mental state ofan502-22165 Agent [1], 2. to postulate a correlation between a speaker's mental state and his uttering a certainsent... | [
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3,039 | 4 | An Application-Independent Intelligent User Support System Exploiting Action-Sequence Based User Modelling . Many software systems' usability suffers from their complexity, usually caused by the market-driven trend to bundle a huge amount of features, which are supposed to increase the product's attractiveness. This attempt, however, more often than not leads to software with poor usability characteristics, therefore requiring an extensive amount of initial effort for the users to become familiar with the system. One way to overcome this problem is by providing user-adapted usage support. In this paper we present an experimental system for intelligent user support, which has been developed under the aspect of portability. Focusing on this goal, the system supports a variety of user- and task-modeling approaches and is independent from the hosting software application environment, thus being ready to integrate with existing and new applications. The different user-modeling approaches have been empirically evaluated and compared in a medical software application embedding our syste... | [
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3,040 | 3 | Scalable Maintenance in Distributed Data Warehousing Environment The maintenance of data warehouses is becoming an increasingly important topic due to the growing use, derivation and integration of digital information. Most previous work has dealt with one centralized data warehouse (DW) only. In this paper, we now focus on environments with multiple data warehouses that are possibly derived from other data warehouses. In such a large-scale environment, data updates from base sources may arrive in individual data warehouses in different orders, thus resulting in inconsistent data warehouse extents. We propose a registry-based solution strategy that addresses this problem by employing a registry agent responsible for establishing one unique order for the propagation of updates from the base sources to the data warehouses. With this solution, individual data warehouse managers can still maintain their respective extents autonomously and independently from each other, thus allowing them to apply any of the existing incremental maintenance algo... | [
1018,
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] | Test |
3,041 | 1 | Learning Decision Trees for Loss Minimization in Multi-Class Problems Many machine learning applications require classifiers that minimize an asymmetric loss function rather than the raw misclassification rate. We study methods for modifying C4.5 to incorporate arbitrary loss matrices. One way to incorporate loss information into C4.5 is to manipulate the weights assigned to the examples from different classes. For 2-class problems, this works for any loss matrix, but for k ? 2 classes, it is not sufficient. Nonetheless, we ask what is the set of class weights that best approximates an arbitrary k \Theta k loss matrix, and we test and compare several methods: a wrapper method and some simple heuristics. The best method is a wrapper method that directly optimizes the loss using a hold-out data set. We define complexity measure for loss matrices and show that this measure can predict when more efficient methods will suffice and when the wrapper method must be applied. 1 Introduction For most of the history of machine learning research, a central goal has ... | [
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3,042 | 4 | Developing Adaptable User Interfaces for Component-based Systems Developing software components with user interfaces that can be adapted to diverse reuse situations is challenging. Examples of such adaptations include extending, composing and reconfiguring multiple component user interfaces, and adapting component user interfaces to particular user preferences, roles and subtasks. We describe our recent work in facilitating such adaptation via the concept of user interface aspects, which facilitate effective component user interface design and realisation using an extended, component-based software architecture. 1. Introduction Component-based software applications are composed from diverse software components to form an application [1, 14, 16, 17]. Typically many of these components have been developed separately, with no knowledge of the user interfaces of other components they may be composed with. This can result in component-based applications with inappropriate, inconsistent interfaces. For example, two components with user interfaces that ... | [
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3,043 | 3 | Cyclic Association Rules We study the problem of discovering association rules that display regular cyclic variation over time. For example, if we compute association rules over monthly sales data, we may observe seasonal variation where certain rules are true at approximately the same month each year. Similarly, association rules can also display regular hourly, daily, weekly, etc., variation that is cyclical in nature. We demonstrate that existing methods cannot be naively extended to solve this problem of cyclic association rules. We then present two new algorithms for discovering such rules. The first one, which we call the sequential algorithm, treats association rules and cycles more or less independently. By studying the interaction between association rules and time, we devise a new technique called cycle pruning, which reduces the amount of time needed to find cyclic association rules. The second algorithm, which we call the interleaved algorithm, uses cycle pruning and other optimization techniques f... | [
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3,044 | 2 | Experiments In Information Retrieval From Spoken Documents This paper describes the experiments performed as part of the TREC-97 Spoken Document Retrieval Track. The task was to pick the correct document from 35 hours of recognized speech documents, based on a text query describing exactly one document. Among the experiments we described here are: Vocabulary size experiments to assess the effect of words missing from the speech recognition vocabulary; experiments with speech recognition using a stemmed language model; using confidence annotations that estimate of the correctness of each recognized word; using multiple hypotheses from the recognizer. And finally we also measured the effects of corpus size on the SDR task. Despite fairly high word error rates, information retrieval performance was only slightly degraded for speech recognizer transcribed documents. 1. INTRODUCTION For the first time, the 1997 Text REtrieval Conference (TREC97) included an evaluation track for information retrieval on spoken documents. In this paper, we describe ... | [
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3,045 | 4 | On the Expressiveness of Distributed Leasing in Linda-like Coordination Languages S. All local authors can be reached via e-mail at the address last-name@cs.unibo.it. Questions and comments should be addressed to tr-admin@cs.unibo.it. Recent Titles from the UBLCS Technical Report Series 99-2 A Theory of Efficiency for Markovian Processes, M. Bernardo, W.R. Cleaveland, February 1999 (Revisied March 2000). 99-3 A Reliable Registry for the Jgroup Distributed Object Model, A. Montresor, March 1999. 99-4 Comparing the QoS of Internet Audio Mechanisms via Formal Methods, A. Aldini, M. Bernardo, R. Gorrieri, M. Roccetti, March 1999. 99-5 Group-Enhanced Remote Method Invocations, A. Montresor, R. Davoli, O. Babao glu, April 1999. 99-6 Managing Complex Documents Over the WWW: a Case Study for XML, P. Ciancarini, F. Vitali, C. Mascolo, April 1999. 99-7 Data-Flow Hard Real-Time Programs: Scheduling Processors and Communication Channels in a Distributed Environment, R. Davoli, F. Tamburini, April 1999. 99-8 The MPS Computer System Simulator, M. Morsiani, R. Davoli, Apri... | [
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3,046 | 1 | Optimizing Learning in Image Retrieval Combining learning with vision techniques in interactive image retrieval has been an active research topic during the past few years. However, existing learning techniques either are based on heuristics or fail to analyze the working conditions. Furthermore, there is almost no in depth study on how to effectively learn from the users when there are multiple visual features in the retrieval system. To address these limitations, in this paper, we present a vigorous optimization formulation of the learning process and solve the problem in a principled way. By using Lagrange multipliers, we have derived explicit solutions, which are both optimal and fast to compute. Extensive comparisons against state-ofthe-art techniques have been performed. Experiments were carried out on a large-size heterogeneous image collection consisting of 17,000 images. Retrieval performance was tested under a wide range of conditions. Various evaluation criteria, including precision-recall curve and rank measure, have demonstrated the effectiveness and robustness of the proposed technique. 1. | [
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3,047 | 2 | Normalization and matching in the DORO system This paper is concerned with the use of linguistically motivated phrases as indexing terms in Information Retrieval applications. Apart from the conventional noun phrases, we propose to use verb phrases as index terms for text classification. Techniques for phrase matching through syntactic normalization and semantical matching are described. In particular, we show how to perform syntactic normalization of phrases in order to enhance recall. Semantical normalization is based on lexico-semantical relations, taking into account certain properties of the classification algorithms used. The ideas described here are being implemented in the Document Routing system DORO, in which statistical learning algorithms are applied to document profiles consisting of phrases. This paper describes the rationale behind work in progress, rather than presenting final results. | [
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3,048 | 2 | The Deep Web: Surfacing Hidden Value this document is preliminary. BrightPlanet plans future revisions as better information and documentation is obtained. We welcome submission of improved information and statistics from others involved with the "deep" Web. Mata Hari is a registered trademark and BrightPlanet^TM, CompletePlanet^TM, LexiBot^TM, search filter^TM and A Better Way to Search^TM are pending trademarks of BrightPlanet.com LLC. All other trademarks are the respective property of their registered owners. 2000 BrightPlanet.com LLC. All rights reserved. The Deep Web: Surfacing Hidden Value iii | [
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3,049 | 4 | Context-Aware Telephony over WAP . In this paper we introduce a novel approach to share context to enhance the social quality of remote mobile communication. We provide an analysis of how people start a conversation in situations where they meet physically, especially looking on the influence of the situation. Than this is compared to the way remote communication is initiated using mobile phones. The lack of knowledge about the situation on the other end leads to initiation of calls that are not appropriate in the situation. The solution we propose is to exchange context information before initiating the call. We implemented this concept using the Wireless Application Protocol (WAP). The WML-based Application Context-Call offers a phone interface that provides information about the receiver when setting up a call. The caller can than decide based on that information to place the call, to leave a message or to cancel the call. Privacy issues that arise from this technology are discussed, too. Keywords: Contex... | [
180,
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3,050 | 3 | Blobworld: Image segmentation using Expectation-Maximization and its application to image querying AbstractÐRetrieving images from large and varied collections using image content as a key is a challenging and important problem. We present a new image representation that provides a transformation from the raw pixel data to a small set of image regions that are coherent in color and texture. This ªBlobworldº representation is created by clustering pixels in a joint color-texture-position feature space. The segmentation algorithm is fully automatic and has been run on a collection of 10,000 natural images. We describe a system that uses the Blobworld representation to retrieve images from this collection. An important aspect of the system is that the user is allowed to view the internal representation of the submitted image and the query results. Similar systems do not offer the user this view into the workings of the system; consequently, query results from these systems can be inexplicable, despite the availability of knobs for adjusting the similarity metrics. By finding image regions that roughly correspond to objects, we allow querying at the level of objects rather than global image properties. We present results indicating that querying for images using Blobworld produces higher precision than does querying using color and texture histograms of the entire image in cases where the image contains distinctive objects. Index TermsÐSegmentation and grouping, image retrieval, image querying, clustering, Expectation-Maximization. 1 | [
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3,051 | 2 | Implicit Interest Indicators Recommender systems provide personalized suggestions about items that users will find interesting. Typically, recommender systems require a user interface that can "intelligently" determine the interest of a user and use this information to make suggestions. The common solution, "explicit ratings", where users tell the system what they think about a piece of information, is well-understood and fairly precise. However, having to stop to enter explicit ratings can alter normal patterns of browsing and reading. A more "intelligent" method is to use implicit ratings, where a rating is obtained by a method other than obtaining it directly from the user. These implicit interest indicators have obvious advantages, including removing the cost of the user rating, and that every user interaction with the system can contribute to an implicit rating. Current recommender systems mostly do not use implicit ratings, nor is the ability of implicit ratings to predict actual user interest well-unders... | [
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] | Train |
3,052 | 4 | A Model of Collision Perception for Real-Time Animation A model of human visual perception of collisions is presented, based on twodimensional measures of eccentricity and separation. The model is validated by performing psychophysical experiments. We demonstrate the feasibility of using this model as the basis for perceptual scheduling of interruptible collision detection in a realtime animation of large numbers of visually homogeneous objects. The user's point of fixation may be either tracked or estimated. By using a priority queue scheduling algorithm, perceived collision inaccuracy was approximately halved. The ideas presented are applicable to other tasks where the processing of fine detail leads to a computational bottleneck. | [] | Train |
3,053 | 1 | A Hierarchical Approach to Wrapper Induction With the tremendous amount of information that becomes available on the Web on a daily basis, the ability to quickly develop information agents has become a crucial problem. A vital component of any Web-based information agent is a set of wrappers that can extract the relevant data from semistructured information sources. Our novel approach to wrapper induction is based on the idea of hierarchical information extraction, which turns the hard problem of extracting data from an arbitrarily complex document into a series of easier extraction tasks. We introduce an inductive algorithm, stalker, that generates high accuracy extraction rules based on user-labeled training examples. Labeling the training data represents the major bottleneck in using wrapper induction techniques, and our experimental results show that stalker does significantly better then other approaches; on one hand, stalker requires up to two orders of magnitude fewer examples than other algorithms, while on the other hand... | [
434,
801,
906,
1090,
1294,
1843,
2661,
2692,
2929,
3098,
3099
] | Test |
3,054 | 1 | Evolution of a Central Pattern Generator for the Swimming and Trotting Gaits of the Salamander This paper presents the development of neural controllers for the swimming and the trotting of a salamanderlike animat. Using a genetic algorithm (GA), we extend a connectionist model of the central pattern generator (CPG) controlling the swimming of a lamprey [1] to control the locomotion of a 2D mechanical simulation of a salamander. We study in particular what kind of neural connectivity can produce the traveling undulation of the trunk during swimming and the standing S-wave undulation during trotting. Using a GA, we evolve neural controllers which are made of two segmental oscillators controlling the fore- and hindlimb muscles, which project to a lamprey-like CPG for the trunk muscles. CPGs are successfully evolved which exhibit the swimming gait when external excitatory drive is applied only to the trunk CPG, and the trotting gait when external drive is applied to both the limb and the trunk CPGs. For both types of gaits, the speed of locomotion can be varied with the amplitude o... | [
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] | Train |
3,055 | 3 | Results on Reasoning about Updates in Transaction Logic . Transaction Logic was designed as a general logic of state change for deductive databases and logic programs. It has a model theory, a proof theory, and its Horn subset can be given a procedural interpretation. Previous work has demonstrated that the combination of declarative semantics and procedural interpretation turns the Horn subset of Transaction Logic into a powerful language for logic programming with updates [BK98,BK94,BK93,BK95]. In this paper, we focus not on the Horn subset, but on the full logic, and we explore its potential as a formalism for reasoning about logic programs with updates. We first develop a methodology for specifying properties of such programs, and then provide a sound inference system for reasoning about them, and conjecture a completeness result. Finally, we illustrate the power of the inference system through a series of examples of increasing difficulty. 1 Introduction Updates are a crucial component of any database programming language. Even the si... | [
2262,
2347
] | Test |
3,056 | 5 | Expert System Technology in Observing Tools Over the past two years, the Scientist's Expert Assistant team from NASA's Goddard Space Flight Center and the Space Telescope Science Institute has been prototyping tools to support General Observer proposal development for the Hubble Space Telescope and the Next Generation Space Telescope. One aspect of this effort has been the exploration of the use of expert systems in guiding the user in preparing their observing program. The initial goal was to provide the user with a question-and-answer style of interaction where the software would "interview" the user for their science needs and recommend instrument settings. This design ultimately failed. The reasons for this failure, and the resulting evolution of our approach, are an interesting case study in the use of expert system technology for observing tools. Although the interview approach failed we felt that expert systems can still be used in the tools environment. This paper describes our current approach to the use of expert syste... | [
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3,057 | 0 | BDI Design Principles and Cooperative Implementation - A Report on RoboCup Agents This report discusses two major views on BDI deliberation for autonomous agents. The first view is a rather conceptual one, presenting general BDI design principles, namely heuristic options, decomposed reasoning and layered planning, which enable BDI deliberation in realtime domains. The second view is focused on the practical application of the design principles in RoboCup Simulation League. This application not only evaluates the usefulness in deliberation but also the usefulness in rapid cooperative implementation. We compare this new approach, which has been used in the Vice World Champion team AT Humboldt 98, to the old approach of AT Humboldt 97, and we outline the extensions for AT Humboldt 99, which are still under work. Conditions faced by deliberation in multi agent contexts differ significantly from the basic assumption of classical AI search and planning. Traditional game playing methods for example assume a static well-known setting and a fixed round-based interaction of ... | [
1842,
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] | Train |
3,058 | 3 | The FERET Evaluation Methodology for Face-Recognition Algorithms Two of the most critical requirements in support of producing reliable face-recognition systems are a large database of facial images and a testing procedure to evaluate systems. The Face Recognition Technology (FERET) program has addressed both issues through the FERET database of facial images and the establishment of the FERET tests. To date, 14,126 images from 1199 individuals are included in the FERET database, which is divided into development and sequestered portions of the database. In September 1996, the FERET program administered the third in a series of FERET face-recognition tests. The primary objectives of the third test were to (1) assess the state of the art, (2) identify future areas of research, and (3) measure algorithm performance. 1 Introduction Over the last decade, face recognition has become an active area of research in computer vision, neuroscience, and psychology. Progress has advanced to the point that face-recognition systems are being demonstrated in real-... | [
167,
747,
859,
1846,
2067,
2269,
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] | Train |
3,059 | 3 | Modeling and optimizing I/O throughput of multiple disks on a bus In modern I/O architectures, multiple disk drives are attached to each I/O controller. A study of the performance of such architectures under I/O-intensive workloads has revealed a performance impairment that results from a previously unknown form of convoy behavior in disk I/O. In this paper, we describe measurements of the read performance of multiple disks that share a SCSI bus under a heavy workload, and develop and validate formulas that accurately characterize the observed performance (to within 12 % on several platforms for I/O sizes in the range 16{128 KB). Two terms in the formula clearly characterize the lost performance seen in our experiments. We describe techniques to deal with the performance impairment, via user-level workarounds that achieve greater overlap of bus transfers with disk seeks, and that increase the percentage of transfers that occur at the full bus bandwidth rather than at the lower bandwidth of a disk head. Experiments show bandwidth improvements of 10-20 % when using these user-level techniques, but only in the case of large I/Os. | [
1214
] | Validation |
3,060 | 3 | Web-Document Prediction And Presending Using Association Rule Sequential Classifiers An important data source for data mining is the web-log data that traces the user's web browsing actions. From the web logs, one can build prediction models that predict with high accuracy the user's next requests based on past behavior. To do this with the traditional classification and association rule methods will cause a number of serious problems due to the extremely large data size and the rich domain knowledge that must be applied. Most web log data are sequential in nature and exhibit the "most recent--most important" behavior. To overcome this difficulty, we examine two important dimensions of building prediction models, namely the type of antecedents of rules and the criterion for selecting prediction rules. This thesis proposes a better overall method for prediction model representation and refinement. We show empirically on realistic web log data that the proposed model dramatically outperforms previous ones. How to apply the learned prediction model to the task of presending web documents is also demonstrated. iv Dedication To MY MOTHER only v Acknowledgments I would like to thank my senior supervisor, Dr. Qiang Yang, for his guidance, encouragement and invaluable advice during my research. His enthusiasm and devotion to research have given me great inspiration to accomplish this thesis. It would be hard to imagine finishing this thesis without his continuous support. My gratitude also goes to my supervisor Dr. Ke Wang and the external examiner, Dr. Jiawei Han, who share with me their boundless knowledge in the area of Data Mining, and provide me valuable feedback on my thesis. I also gratefully acknowledge the unselfish help given to me by my old friend Henry Zhang. I have always learnt a lot from his amazing wisdom and creative thought over the crit... | [
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3,061 | 2 | Analyzing Web Robots and Their Impact on Caching Understanding the nature and the characteristics of Web robots is an essential step to analyze their impact on caching. Using a multi-layer hierarchical workload model, this paper presents a characterization of the workload generated by autonomous agents and robots. This characterization focuses on the statistical properties of the arrival process and on the robot behavior graph model. A set of criteria is proposed for identifying robots in real logs. We then identify and characterize robots from real logs applying a multi-layered approach. Using a stack distance based analytical model for the interaction between robots and Web site caching, we assess the impact of robots' requests on Web caches. Our analyses point out that robots cause a significant increase in the miss ratio of a server-side cache. Robots have a referencing pattern that completely disrupts locality assumptions. These results indicate not only the need for a better understanding of the behavior of robots, but also the need of Web caching policies that treat robots' requests differently than human generated requests. | [
433,
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3,062 | 3 | Joint Optimization of Cost and Coverage of Query Plans in Data Integration Existing approaches for optimizing queries in data integration use decoupled strategies--attempting to optimize coverage and cost in two separate phases. Since sources tend to have a variety of access limitations, such phased optimization of cost and coverage can unfortunately lead to expensive planning as well as highly inefficient plans. In this paper we present techniques for joint optimization of cost and coverage of the query plans. Our algorithms search in the space of parallel query plans that support multiple sources for each subgoal conjunct. The refinement of the partial plans takes into account the potential parallelism between source calls, and the binding compatibilities between the sources included in the plan. We start by introducing and motivating our query plan representation. We then briefly review how to compute the cost and coverage of a parallel plan. Next, we provide both a System-R style query optimization algorithm as well as a greedy local search algorithm for searching in the space of such query plans. Finally we present a simulation study that demonstrates that the plans generated by our approach will be significantly better, both in terms of planning cost, and in terms of plan execution cost, compared to the existing approaches. 1. | [
475,
634,
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] | Train |
3,063 | 1 | Self Bounding Learning Algorithms Most of the work which attempts to give bounds on the generalization error of the hypothesis generated by a learning algorithm is based on methods from the theory of uniform convergence. These bounds are a-priori bounds that hold for any distribution of examples and are calculated before any data is observed. In this paper we propose a different approach for bounding the generalization error after the data has been observed. A self-bounding learning algorithm is an algorithm which, in addition to the hypothesis that it outputs, outputs a reliable upper bound on the generalization error of this hypothesis. We first explore the idea in the statistical query learning framework of Kearns [10]. After that we give an explicit self bounding algorithm for learning algorithms that are based on local search. 1 INTRODUCTION Most of the work on the sample complexity of learning is based on uniform convergence theory and attempts to give uniform a-priori bounds. A uniform a-priori bound is a guar... | [
2175
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3,064 | 3 | Multifaceted Object Modeling with Roles: A Comprehensive Approach In conventional object-oriented (O-O) database systems, it is assumed silently that fundamental object types and inter-object relationships can be classfied statically, prescribing basic structural and behavioral properties for all the objects in the database. Such a classification-based approach falls short of supporting emerging data-intensive applications requiring more advanced dynamic capabilities. One of such advanced capabilities is the support of modeling subjectivity -- the ability to (among others) provide multiple perspectives of application objects or to model socalled "multifaceted objects" which, on different stages, can exhibit different forms and behavior. This article describes an extended O-O approach that we have been investigating for this purpose. Advanced features embodied by dynamic and versatile role facilities have been introduced into a conventional object-oriented model, which facilitates specifying and modeling such applications in a natural, incremental and... | [
822
] | Train |
3,065 | 2 | Integrating Community Services - A Common Infrastructure Proposal Computer based community systems can provide powerful support in knowledge transfer, both in the direct exchange of information and in finding people to exchange information with. Several such information exchange and expert finding services have already been implemented. The problem of current approaches is, that they are not able to exchange data with each other. User profile information and contributed information have to be entered separately for every community-based information system. So, what one system has learned is not available for other systems. In this paper we present our ideas for a community services infrastructure as an enabling technology for further integration of community related services. | [
1009
] | Test |
3,066 | 0 | Specification and Simulation of Multi-Agent Systems in CaseLP Nowadays software applications are characterized by a great complexity. It arises from the need of reusing existing components and properly integrating them. The distribution of the involved entities and their heterogeneity makes it very useful the adoption of the agent-oriented technology. The paper presents the state-of-the-art of CaseLP, an experimental logic-based prototyping environment for multi-agent systems. CaseLP provides a prototyping method and a set of tools and languages which support the prototype realization. At the system specification level, an architectural description language can be adopted to describe the prototype in terms of agents classes, instances, their provided and required services and their communication links. At the agent specification level, a rule-based, not executable language can be used to easily define reactive and proactive agents. An executable, linear logic language can define more sophisticated agents and the system in which they operate. At t... | [
239,
1076,
2160,
2432,
2527
] | Test |
3,067 | 5 | Strict Archimedean t-Norms and t-Conorms as Universal Approximators In knowledge representation, when we have to use logical connectives, various continuous t-norms and t-conorms are used. In this paper, we show that every continuous t-norm and t-conorm can be approximated, to an arbitrary degree of accuracy, by a strict Archimedean t-norm (t-conorm). Address correspondence to Vladik Kreinovich, Department of Computer Science, University of Texas at El Paso, El Paso, TX 79968, USA, email vladik@cs.utep.edu. International Journal of Approximate Reasoning 199? ?:?--? c fl 199? Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010 0888-613X/9?/$7.00 2 1. INTRODUCTION Brief idea. When we represent expert knowledge in expert systems and in intelligent control, it is important to adequately describe not only the experts' statements themselves, but also the experts' degrees of confidence in the corresponding statements. It is also important to adequately describe which operations with these degrees of confidence are best representing the expe... | [
11,
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] | Train |
3,068 | 1 | Active Storage for Large-Scale Data Mining and Multimedia The increasing performance and decreasing cost of processors and memory are causing system intelligence to move into peripherals from the CPU. Storage system designers are using this trend toward “excess ” compute power to perform more complex processing and optimizations inside storage devices. To date, such optimiza-tions have been at relatively low levels of the stor-age protocol. At the same time, trends in storage density, mechanics, and electronics are eliminat-ing the bottleneck in moving data off the media and putting pressure on interconnects and host processors to move data more efficiently. We pro-pose a system called Active Disks that takes advantage of processing power on individual disk drives to run application-level code. Moving por-tions of an application’s processing to execute directly at disk drives can dramatically reduce data traffic and take advantage of the storage par-allelism already present in large systems today. We discuss several types of applications that would benefit from this capability with a focus on the areas of database, data mining, and multime-dia. We develop an analytical model of the speed-ups possible for scan-intensive applications in an Active Disk system. We also experiment with a prototype Active Disk system using relatively low-powered processors in comparison to a data-base server system with a single, fast processor. Our experiments validate the intuition in our model and demonstrate speedups of 2x on 10 disks across four scan-based applications. The model promises linear speedups in disk arrays of hundreds of disks, provided the application data is large enough. Thts research was sponsored by DARPAflTO through Order D306, and issued by Indian Head Division, NSWC under contract NOO174-96-0002. Additional support was prowded by NSF under grants EEC-94-02384 and IRI-9625428 and NSF, ARPA and NASA under NSF Agreement IRI-9411299. We are also Indebted to generous contributions from the member companies of the Parallel Data Consortium: Hewlett- | [
104,
730,
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] | Train |
3,069 | 3 | Efficient OLAP Operations in SPatial Data Warehouses Abstract. Spatial databases store information about the position of individual objects in space. In many applications however, such as traffic supervision or mobile communications, only summarized data, like the number of cars in an area or phones serviced by a cell, is required. Although this information can be obtained from transactional spatial databases, its computation is expensive, rendering online processing inapplicable. Driven by the non-spatial paradigm, spatial data warehouses can be constructed to accelerate spatial OLAP operations. In this paper we consider the star-schema and we focus on the spatial dimensions. Unlike the non-spatial case, the groupings and the hierarchies can be numerous and unknown at design time, therefore the wellknown materialization techniques are not directly applicable. In order to address this problem, we construct an ad-hoc grouping hierarchy based on the spatial index at the finest spatial granularity. We incorporate this hierarchy in the lattice model and present efficient methods to process arbitrary aggregations. We finally extend our technique to moving objects by employing incremental update methods. 1 | [
2806
] | Validation |
3,070 | 1 | Analog Neural Nets with Gaussian or other Common Noise Distributions cannot Recognize Arbitrary Regular Languages We consider recurrent analog neural nets where the output of each gate is subject to Gaussian noise, or any other common noise distribution that is nonzero on a large set. We show that many regular languages cannot be recognized by networks of this type, and we give a precise characterization of those languages which can be recognized. This result implies severe constraints on possibilities for constructing recurrent analog neural nets that are robust against realistic types of analog noise. On the other hand we present a method for constructing feedforward analog neural nets that are robust with regard to analog noise of this type. 1 Introduction A fairly large literature (see [Omlin, Giles, 1996] and the references therein) is devoted to the construction of analog neural nets that recognize regular languages. Any physical realization of the analog computational units of an analog neural net in technological or biological systems is bound to encounter some form of "imprecision" or an... | [
205,
905,
2976
] | Validation |
3,071 | 0 | Using Diagnosis to Learn Contextual Coordination Rules Knowing when and how to communicate and coordinate with other agents in a multi-agent system is an important efficiency and reliability question. Contextual rules governing this communication must be provided to the agent, or generated at runtime through environmental analysis. In this paper we describe how the TAEMS task modeling language is used to encode such contextual coordination rules, and how runtime diagnosis can be used to dynamically update them. Overview Communication and coordination is an essential component of most complex multi-agent systems. Contention over shared resources, the desire to employ remote information and the need to coordinate interrelated activities may each require some sort of information transfer between agents to be resolved. To this end, individual actors in a multi-agent system must be able to explicitly or implicitly communicate requests and results, desires and beliefs, to make the system an efficient and cohesive unit. Thus, a set of situation-... | [
1210,
2358
] | Test |
3,072 | 2 | Self-Organization and Identification of Web Communities The vast improvement in information access is not the only advantage resulting from the increasing percentage of hyperlinked human knowledge available on the Web. Additionally, much potential exists for analyzing interests and relationships within science and society. However, the Web's decentralized and unorganized nature hampers content analysis. Millions of individuals operating independently and having a variety of backgrounds, knowledge, goals and cultures author the information on the Web. Despite the Web's decentralized, unorganized, and heterogeneous nature, our work shows that the Web self-organizes and its link structure allows efficient identification of communities. This self-organization is significant because no central authority or process governs the formation and structure of hyperlinks. | [
1838,
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] | Test |
3,073 | 3 | Versus: a Model for a Web Repository Web data warehouses can prove useful to applications that process large amounts of Web data. Versus is a model for a Repository for Web data management applications, supporting object versioning and distributed operation. Versus applications control the distribution, and the integration of data. This paper presents the design of Versus and our prototype implementation. Keywords: Web data repository, versioning, distributed database. | [
1170
] | Test |
3,074 | 5 | Constrained Genetic Algorithms and their Applications in Nonlinear Constrained Optimization This chapter presents a framework that unifies various search mechanisms for solving constrained nonlinear programming (NLP) problems. These problems are characterized by functions that are not necessarily differentiable and continuous. Our proposed framework is based on the first-order necessary and sufficient condition developed for constrained local minimization in discrete space that shows the equivalence between discrete-neighborhood saddle points and constrained local minima. To look for discrete-neighborhood saddle points, we formulate a discrete constrained NLP in an augmented Lagrangian function and study various mechanisms for performing ascents of the augmented function in the original-variable subspace and descents in the Lagrange-multiplier subspace. Our results show that CSAGA, a combined constrained simulated annealing and genetic algorithm, performs well when using crossovers, mutations, and annealing to generate trial points. Finally, we apply iterative deepening to de... | [
417
] | Train |
3,075 | 3 | Declarative Semantics of Belief Queries in MLS Deductive Databases (Extended Abstract) A logic based language, called MultiLog, for multi level secure relational databases has recently been proposed. It has been shown that MultiLog is capable of capturing the notion of user belief, of ltering unwanted and \useless" information in its proof theory. Additionally, it can guard against a previously unknown security breach { the so called surprise stories. In this paper, we outline a possible approach to a declarative characterization of belief queries in MultiLog in a very informal manner. We show that for \simple programs" with belief queries, the semantics is rather straight forward. Semantics for the general Horn programs may be developed based on the understanding of the model theoretic characterization of belief queries developed in this paper. Keywords: Multi level security, belief queries, declarative semantics, completeness. Introduction In a recent research, Jukic and Vrbsky [8] demonstrate that users in the relational MLS model potentially have a cluttered view... | [
2326
] | Validation |
3,076 | 0 | A Framework for Norm-Based Inter-Agent Dependence A significant class of agent architectures designed for operation in a multi-agent world choose their next actions or plans based on a limited analysis | [
620,
3177
] | Validation |
3,077 | 2 | Efficient Identification of Web Communities We dene a community on the web as a set of sites that have more links (in either direction) to members of the community than to non-members. Members of such a community can be eciently identied in a maximum ow / minimum cut framework, where the source is composed of known members, and the sink consists of well-known non-members. A focused crawler that crawls to a xed depth can approximate community membership by augmenting the graph induced by the crawl with links to a virtual sink node. The effectiveness of the approximation algorithm is demonstrated with several crawl results that identify hubs, authorities, web rings, and other link topologies that are useful but not easily categorized. Applications of our approach include focused crawlers and search engines, automatic population of portal categories, and improved ltering. Categories and Subject Descriptors H.2.8 [Database Management]: Database Applications| data mining ; H.3.3 [Information Storage and Retrieval]: Information... | [
1108,
1180,
1307,
1352,
1420,
2178,
2565,
3016,
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] | Test |
3,078 | 2 | Partially labeled classification with Markov random walks To classify a large number of unlabeled examples we combine a limited number of labeled examples with a Markov random walk representation over the unlabeled examples. The random walk representation exploits any low dimensional structure in the data in a robust, probabilistic manner. We develop and compare several estimation criteria/algorithms suited to this representation. This includes in particular multi-way classification with an average margin criterion which permits a closed form solution. The time scale of the random walk regularizes the representation and can be set through a margin-based criterion favoring unambiguous classification. We also extend this basic regularization by adapting time scales for individual examples. We demonstrate the approach on synthetic examples and on text classification problems. | [
988,
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] | Train |
3,079 | 3 | Sequence Mining in Categorical Domains: Incorporating Constraints We present cSPADE, an efficient algorithm for mining frequent sequences considering a variety of syntactic constraints. These take the form of length or width limitations on the sequences, minimum or maximum gap constraints on consecutive sequence elements, applying a time window on allowable sequences, incorporating item constraints, and finding sequences predictive of one or more classes, even rare ones. Our method is efficient and scalable. Experiments on a number of synthetic and real databases show the utility and performance of considering such constraints on the set of mined sequences. 1. | [
425
] | Validation |
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