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1,980 | 1 | L-Fuzzy Valued Inclusion Measure, L-Fuzzy Similarity and L-Fuzzy Distance The starting point of this paper is the introduction of a new measure of inclusion of fuzzy set A in fuzzy set B. Previously used inclusion measures take values in the interval [0,1]; the inclusion measure proposed here takes values in a Boolean lattice. In other words, inclusion is viewed as an Lfuzzy valued relation between fuzzy sets. This relation is reflexive, antisymmetric and transitive, i.e. it is a fuzzy order relation; in addition it possesess a number of properties which various authors have postulated as axiomatically appropriate for an inclusion measure. We also define an L-fuzzy valued measure of similarity between fuzzy sets and and an L-fuzzy valued distance function between fuzzy sets; these possess properties analogous to the ones of real-valued similarity and distance functions. Keywords: Fuzzy Relations, inclusion measure, subsethood, L-fuzzy sets, similarity, distance, transitivity. 1 | [
670
] | Validation |
1,981 | 0 | Modelling Rational Inquiry in Non-Ideal Agents The construction of rational agents is one of the goals that has been pursued in Artificial Intelligence (AI). In most of the architectures that have been proposed for this kind of agents, its behaviour is guided by its set of beliefs. In our work, rational agents are those systems that are permanently engaged in the process of rational inquiry; thus, their beliefs keep evolving in time, as a consequence of their internal inference procedures and their interaction with the environment. Both AI researchers and philosophers are interested in having a formal model of this process, and this is the main topic in our work. Beliefs have been formally modelled in the last decades using doxastic logics. The possible worlds model and its associated Kripke semantics provide an intuitive semantics for these logics, but they seem to commit us to model agents that are logically omniscient and perfect reasoners. We avoid these problems by replacing possible worlds by conceivable situations, which ar... | [
942,
1689,
1812
] | Train |
1,982 | 3 | Adaptive-FP: An Efficient And Effective Method For Multi-Level Multi-Dimensional Frequent Pattern Mining Real life transaction databases usually contain both item information and dimension information. Moreover, taxonomies about items likely exist. Knowledge about multilevel and multi-dimensional frequent patterns is interesting and useful. The classic frequent pattern mining algorithms based on a uniform minimum support, such as Apriori and FP-growth, either miss interesting patterns of low support or suffer from the bottleneck of itemset generation. Other frequent pattern mining algorithms, such as Adaptive Apriori, though taking various supports, focus mining at a single abstraction level. Furthermore, as an Apriori-based algorithm, the efficiency of Adaptive Apriori suffers from the multiple database scans. In this thesis, we extend FP-growth to attack the problem of multi-level multidimensional frequent pattern mining. We call our algorithm Ada-FP, which stands for Adaptive FP-growth. The efficiency of our Ada-FP is guaranteed by the high scalability of FP-growth. To increase the effectiveness, our Ada-FP pushes various support constraints into the mining process. First, item taxonomy has been explored. Our Ada-FP can discover both inter-level frequent patterns and intra-level frequent patterns. Second, in our Ada-FP, dimension information has been taken into account. We show that our Ada-FP is more flexible at capturing desired knowledge than previous studies. | [
1956
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1,983 | 4 | Evaluating Emergent Collaboration on the Web Links between web sites can be seen as evidence of a type of emergent collaboration among web site authors. We report here on an empirical investigation into emergent collaboration. We developed a webcrawling algorithm and tested its performance on topics volunteered by 30 subjects. Our findings include: . Some topics exhibit emergent collaboration, some do not. The presence of commercial sites reduces collaboration. . When sites are linked with other sites, they tend to group into one large, tightly connected component. . Connectivity can serve as the basis for collaborative filtering. Human experts rate connected sites as significantly more relevant and of higher quality. Keywords Social filtering, collaborative filtering, computer supported cooperative work, human computer interaction, information access, information retrieval INTRODUCTION The field of CSCW sees collaboration as involving people who know they are working together, e.g., to edit a document, to carry out a soft... | [
471,
742,
1201,
1307,
1976,
2565,
3090
] | Validation |
1,984 | 1 | Compact Fuzzy Models Through Complexity Reduction and Evolutionary Optimization Genetic Algorithms (GAs) and other evolutionary optimization methods to design fuzzy rules from data for systems modeling and classification have received much attention in recent literature. We show that different tools for modeling and complexity reduction can be favorably combined in a scheme with GA-based parameter optimization. Fuzzy clustering, rule reduction, rule base simplification and constrained genetic optimization are integrated in a data-driven modeling scheme with low human intervention. Attractive models with respect to compactness, transparency and accuracy, are the result of this symbiosis. I. INTRODUCTION We focus on learning fuzzy rules from data with low human intervention. Many tools to initialize, tune and manipulate fuzzy models have been developed. We show that different tools can be favorably combined to obtain compact fuzzy rule-based models of low complexity with still good approximation accuracy. A modeling scheme is presented that combine four pr... | [
351,
584,
1267,
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] | Train |
1,985 | 0 | Autonomous Cyber Agents: Rules For Collaboration A cyber agent is any program, machine or person engaged in computer-enabled work. Thus, cyber agents can vary considerably in complexity and intelligence. Can they, despite their variety, be organized to collaborate effectively ? Both empirical evidence and theory suggest that they can. Moreover, there seem to be simple rules for designing problem-solving organizations in which collaboration among cyber agents is automatic and scale-effective (adding agents tends to improve solution-quality; adding computers tends to improve solution-speed). This paper develops some of these rules. 1. INTRODUCTION Computer networks make it possible to interconnect and therefore, organize, large numbers of distributed cyber agents, varying in type from simple programs to skilled humans. Our goal is to develop a class of organizations in which such agents can collaborate easily and effectively. More specifically, our goal is to develop methods for routinely solving arbitrary instances of the following ... | [
1155,
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] | Test |
1,986 | 1 | Integration Of Speech And Vision Using Mutual Information We are developing a system which learns words from co-occurring spoken and visual input. The goal is to automatically segment continuous speechatword boundaries without a lexicon, and to form visual categories which correspond to spoken words. Mutual information is used to integrate acoustic and visual distance metrics in order to extract an audio-visual lexicon from raw input. Wereport results of experiments with a corpus of infant-directed speech and images. 1. INTRODUCTION We are developing systems which learn words from co-occurring audio and visual input [5, 4]. Input consists of naturally spoken mutliword utterances paired with visual representations of object shapes (Figure 1). Output of the system is an audio-visual lexicon of sound-shape associations which encode acoustic forms of words (or phrases) and their visually grounded referents. We assume that, in general, the audio and visual signals are uncorrelated in time. However, when a wordisspoken, its visual representatio... | [
1419,
2044
] | Train |
1,987 | 1 | Using Reinforcement Learning to Spider the Web Efficiently Consider the task of exploring the Web in order to find pages of a particular kind or on a particular topic. This task arises in the construction of search engines and Web knowledge bases. This paper argues that the creation of efficient web spiders is best framed and solved by reinforcement learning, a branch of machine learning that concerns itself with optimal sequential decision making. One strength of reinforcement learning is that it provides a formalism for measuring the utility of actions that give benefit only in the future. We present an algorithm for learning a value function that maps hyperlinks to future discounted reward by using naive Bayes text classifiers. Experiments on two real-world spidering tasks show a three-fold improvement in spidering efficiency over traditional breadth-first search, and up to a two-fold improvement over reinforcement learning with immediate reward only. Keywords: reinforcement learning, text classification, World Wide Web, spidering, crawlin... | [
95,
166,
759,
848,
1108,
1394,
1420,
1750,
2371
] | Validation |
1,988 | 1 | Using Case-Based Learning to Improve Genetic-Algorithm-Based Design Optimization In this paper we describe a method for improving genetic-algorithm-based optimization using case-based learning. The idea is to utilize the sequence of points explored during a search to guide further exploration. The proposed method is particularly suitable for continuous spaces with expensive evaluation functions, such as arise in engineering design. Empirical results in two engineering design domains and across different representations demonstrate that the proposed method can significantly improve the efficiency and reliability of the GA optimizer. Moreover, the results suggest that the modification makes the genetic algorithm less sensitive to poor choices of tuning parameters such as mutation rate. 1 Introduction Genetic Algorithms (GAs) [ Goldberg 1989 ] are search algorithms that simulate the process of natural selection. GAs attempt to find a good solution to some problem (e.g., finding the maximum of a function) by randomly generating a collection ("population") of potential... | [
1142
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1,989 | 1 | Enhancing the Sense of Other Learners in Student-Centred Web-Based Education Student-centred learning can be used in Web-courses to increase student activity, motivation and commitment. EDUCO is a system for student-centred learning, both for the learners and the teachers. Students can use EDUCO within a standard web-browser to navigate towards useful information and Web-resources gathered into the system. The key issue is that every participant can see everyone else in the system and their navigational steps, so that the feeling of student companions taking part in the same tasks is increased. The implications of this type of social navigation are discussed along with the description of the system itself. 1. | [
388,
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1,990 | 4 | Information Visualization, Human-Computer Interaction, and Cognitive Psychology: Domain Visualizations Digital libraries stand to benefit from technology insertions from the fields of information visualization, human-computer interaction, and cognitive psychology, among others. However, the current state of interaction between these fields is not well understood. We use our knowledge visualization tool, VxInsight | [
775,
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] | Test |
1,991 | 1 | Antitonic Logic Programs We propose a framework which extends Antitonic Logic Programs [3] to an arbitrary complete bilattice of truth-values, where belief and doubt are explicitly represented. Based on Fitting's ideas, this framework allows a precise definition of important operators found in logic programming such as explicit negation and the default negation. In particular, it leads to a natural integration of explicit negation with the default negation through the coherence principle [20]. According to this principle, the explicit negation entails the default negation. We then define Coherent Answer Sets, and the Paraconsistent Well-founded Model semantics, generalizing paraconsistent semantics for logic programs (for instance, WFSXp [2]). Our framework is an extension of Antitonic Logic Programs in the most cases, and is general enough to capture Probabilistic Deductive Databases, Possibilistic Logic Programming, Hybrid Probabilistic Logic Programs, and Fuzzy Logic Programming. Thus, we have a powerful mathematical formalism for dealing with default reasoning, paraconsistency, and uncertainty. We illustrate its adumbration of paraconsistency with an embedding of WFSXp into our framework. | [
1906
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1,992 | 4 | Learning Significant Locations and Predicting User Movement with GPS Wearable computers have the potential to act as intelligent agents in everyday life and assist the user in a variety of tasks depending on the context. Location is the most common form of context used by these agents to determine the user's task. However, another potential use is the creation of a predictive model of the user's future movements. We present a system that automatically clusters GPS data taken over an extended period of time into meaningful locations at multiple scales. These locations are then incorporated into a Markov model that can be consulted for use with a variety of applications in both single--user and collaborative scenarios. | [
2473,
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1,993 | 2 | Building a Public Digital Library Based on Full-Text Retrieval Digital libraries are expensive to create and maintain, and generally restricted to a particular corporation or group of paying subscribers. While many indexes to the World Wide Web are freely available, the quality of what is indexed is extremely uneven. The digital analog of a public library---a reliable, quality, community service---has yet to appear. This paper demonstrates the feasibility of a cost-effective collection of high-quality public-domain information, available free over the Internet. One obstacle to the creation of a digital library is the difficulty of providing formal cataloguing information. Without a title, author and subject database it seems hard to offer the searching facilities normally available in physical libraries. Full-text retrieval provides a way of approximating these services without a concomitant investment of resources. A second is the problem of finding a suitable corpus of material. Computer science research reports form the focus of ou... | [
334
] | Validation |
1,994 | 4 | Awareness and Privacy in Mobile Wearable Computers. IPADS: Interpersonal Awareness Devices An Inter-Personal Awareness Device, or IPAD, is a handheld or wearable device designed to support awareness and collaboration between people who are in physical vicinity of each other. This paper describes three IPAD systems, comparing their characteristics and approaches to the problem of opportunistic meeting. The characteristics are identified according to the Steinfield et al. [SJP99] awareness classification. Some of these mechanisms are discussed and some improvements and ideas are proposed in order to improve the systems. Key Words: CSCW, Wearable Computers, Awareness, IPAD, Mobility. 1. Introduction Many studies about collaborative systems are concerned about the use of the desktop workstations and network technologies to provide support for distributed collaborative work and awareness. These systems however, are available on devices that are static and tied to the desk [LH98]. Recently, the development of mobile devices as wearable computers, cellular phones and PDAs (Perso... | [
2008,
2118,
3095
] | Test |
1,995 | 2 | How Does the Observation Strategy Influence the Correctness of Alerting Services? Application elds of alerting services range from digital libraries | [
1893,
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] | Test |
1,996 | 3 | Architectures and Tools for Human-Like Agents 1 This paper discusses agent architectures which are describable in terms of the "higher level" mental concepts applicable to human beings, e.g. "believes", "desires", "intends" and "feels". We conjecture that such concepts are grounded in a type of information processing architecture, and not simply in observable behaviour nor in Newell's knowledge-level concepts, nor Dennett's "intentional stance." A strategy for conceptual exploration of architectures in design-space and nichespace is outlined, including an analysis of design tradeoffs. The SIM AGENT toolkit, developed to support such exploration, including hybrid architectures, is described briefly. Keywords: Architecture, hybrid, mind, emotion, evolution, toolkit. MENTALISTIC DESCRIPTIONS The usual motivation for studying architectures is to explain or replicate performance. Another, less common reason, is to account for concepts. This paper discusses "high level" architectures which can provide a systematic non-behavioural c... | [
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1,997 | 1 | Independent Component Analysis: A flexible non-linearity and decorrelating manifold approach Independent Components Analysis finds a linear transformation to variables which are maximally statistically independent. We examine ICA and algorithms for finding the best transformation from the point of view of maximising the likelihood of the data. In particular, we discuss the way in which scaling of the unmixing matrix permits a "static" nonlinearity to adapt to various marginal densities. We demonstrate a new algorithm that uses generalised exponential functions to model the marginal densities and is able to separate densities with light tails. We characterise the manifold of decorrelating matrices and show that it lies along the ridges of high-likelihood unmixing matrices in the space of all unmixing matrices. We show how to find the optimum ICA matrix on the manifold of decorrelating matrices, and as an example use the algorithm to find independent component basis vectors for an ensemble of portraits. 1 Introduction Finding a natural cooordinate system is an essential first s... | [
1921
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1,998 | 0 | Active User Interfaces The current state of user interfaces for large information spaces imposes an unmanageable cognitive burden upon the user. Determining how to get the right information into the right form with the right tool at the right time has become a monumental task. While advances in graphical user interfaces can partially address this problem, the basic problem of information overload--and under load--can not be solely addressed through development of a better direct manipulation interface to the information space. We survey the state of the art in two research fields, interface agents and user modeling, that address the problem of information overload and under load. First, we take a historical look at how the fields of human-computer interaction and artificial intelligence have viewed interface agent research. Interface agents address the problem of increasing task load by serving as either an assistant or associate, extracting and analyzing relevant information, providing informatio... | [
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1,999 | 2 | A Case Study in Web Search using TREC Algorithms Web search engines rank potentially relevant pages/sites for a user query. Ranking documents for user queries has also been at the heart of the Text REtrieval Conference (TREC in short) under the label ###### retrieval. The TREC community has developed document ranking algorithms that are known to be the best for searching the document collections used in TREC, which are mainly comprised of newswire text. However, the web search community has developed its own methods to rank web pages/sites, many of which use link structure on the web, and are quite dierentfrom the algorithms developed at TREC. This study evaluates the performance of a state-of-the-art keyword-based document ranking algorithm (coming out of TREC) on a popular web search task: nding the web page/site of an entity, #### companies, universities, organizations, individuals, etc. This form of querying is quite prevalentonthe web. The results from the TREC algorithms are compared to four commercial web search engines. Results show that for nding the web page/site of an entity, commercial web search engines are notably better than a state-of-the-art TREC algorithm. These results are in sharp contrast to results from several previous studies. Keywords Search engines, TREC ad-hoc, keyword-based ranking, linkbased ranking 1. | [
2392,
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] | Validation |
2,000 | 1 | A Hybrid Decision Tree/genetic Algorithm for Coping With the Problem of Small Disjuncts in Data Mining The problem of small disjuncts is a serious challenge for data mining algorithms. In essence, small disjuncts are rules covering a small number of examples. Due to their nature, small disjuncts tend to be error prone and contribute to a decrease in predictive accuracy. This paper proposes a hybrid decision tree/genetic algorithm method to cope with the problem of small disjuncts. The basic idea is that examples belonging to large disjuncts are classified by rules produced by a decision-tree algorithm, while examples belonging to small disjuncts (whose classification is considerably more difficult) are classified by rules produced by a genetic algorithm specifically designed for this task. 1 INTRODUCTION In the context of the well-known classification task of data mining, the discovered knowledge is often expressed as a set of IF-THEN rules, since this kind of knowledge representation is intuitive for the user. From a logical viewpoint, typically the discovered rules ar... | [
502
] | Train |
2,001 | 4 | On-line 3D gesture recognition utilising dissimilarity measures In the field of Human-Computer Interaction (HCI), gesture recognition is becoming increasingly important as a mode of communication, in addition to the more common visual, aural and oral modes, and is of particular interest to designers of Augmentative and Alternative Communication (AAC) systems for people with disabilities. A complete microcomputer system is described, GesRec3D, which facilitates the data acquisition, segmentation, learning, and recognition of 3-Dimensional arm gestures. The gesture data is acquired from a Polhemus electro-magnetic tracker system, where sensors are placed on the finger, wrist and elbow of one arm. Coded gestures are linked to user-defined text, to be typed or spoken by a text-to-speech engine, which is integrated into the system. A segmentation method and an algorithm for classification are both presented, which includes acceptance/rejection thresholds based on intra-class and inter-class dissimilarity measures. Results of recognition hits, confusion ... | [
972,
1454
] | Validation |
2,002 | 1 | Different approaches to induce cooperation in fuzzy linguistic models under the COR methodology Nowadays, Linguistic Modeling is considered to be one of the most important areas of application for Fuzzy Logic. It is accomplished by linguistic Fuzzy Rule-Based Systems, whose most interesting feature is the interpolative reasoning developed. This characteristic plays a key role in their high performance and is a consequence of the cooperation among the involved fuzzy rules. A new approach that makes good use of this aspect inducing cooperation among rules is introduced in this contribution: the Cooperative Rules methodology. One of its interesting advantages is its flexibility allowing it to be used with dierent combinatorial search techniques. Thus, four specic metaheuristics are considered: simulated annealing, tabu search, genetic algorithms and ant colony optimization. Their good performance is shown when solving a real-world problem. | [
342,
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] | Train |
2,003 | 2 | S-CREAM -- Semi-automatic CREAtion of Metadata Abstract. Richly interlinked, machine-understandable data constitute the basis for the Semantic Web. We provide a framework, S-CREAM, that allows for creation of metadata and is trainable for a specific domain. Annotating web documents is one of the major techniques for creating metadata on the web. The implementation of S-CREAM, OntoMat supports now the semi-automatic annotation of web pages. This semi-automatic annotation is based on the information extraction component Amilcare. OntoMat extract with the help of Amilcare knowledge structure from web pages through the use of knowledge extraction rules. These rules are the result of a learningcycle based on already annotated pages. 1 | [
409,
512,
2284,
2720,
2862
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2,004 | 3 | Database Schema Matching Using Machine Learning with Feature Selection Schema matching, the problem of finding mappings between the attributes of two semantically related database schemas, is an important aspect of many database applications such as schema integration, data warehousing, and electronic commerce. Unfortunately, schema matching remains largely a manual, labor-intensive process. Furthermore, the effort required is typically linear in the number of schemas to be matched; the next pair of schemas to match is not any easier than the previous pair. In this paper we describe a system, called Automatch, that uses machine learning techniques to automate schema matching. Based primarily on Bayesian learning, the system acquires probabilistic knowledge from examples that have been provided by domain experts. This knowledge is stored in a knowledge base called the attribute dictionary. When presented with a pair of new schemas that need to be matched (and their corresponding database instances), Automatch uses the attribute dictionary to find an optimal matching. We also report initial results from the Automatch project. 1 | [
2448
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2,005 | 4 | Heuristic Evaluation of Groupware Based on the Mechanics of Collaboration . Despite the increasing availability of groupware, most systems are awkward and not widely used. While there are many reasons for this, a significant problem is that groupware is difficult to evaluate. In particular, there are no discount usability evaluation methodologies that can discover problems specific to teamwork. In this paper, we describe how we adapted Nielsen's heuristic evaluation methodology, designed originally for single user applications, to help inspectors rapidly, cheaply effectively identify usability problems within groupware systems. Specifically, we take the `mechanics of collaboration' framework and restate it as heuristics for the purposes of discovering problems in shared visual work surfaces for distance-separated groups. 1. | [
99,
151,
2076,
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2,006 | 1 | Discovering Comprehensible Classification Rules with a Genetic Algorithm This work presents a classification algorithm based on genetic algorithms (GAs) that discovers comprehensible IF-THEN rules, in the spirit of data mining. The proposed GA has a flexible chromosome encoding where each chromosome corresponds to a classification rule. Although the number of genes (genotype) is fixed, the number of rule conditions (phenotype) is variable. The GA also has specific mutation operators for this chromosome encoding. The algorithm was evaluated on two public domain, realworld data sets (on the medical domains of dermatology and breast cancer). 1 Introduction This work presents a system based on genetic algorithms (GAs) to perform the task of classification. The system is evaluated in two medical domains: diagnosis of dermatological diseases and prediction of recurrence of breast cancer. The use of GAs in classification is an attempt to effectively exploit the large search space usually associated with classification tasks. The GA presented here was designed ac... | [
2722
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2,007 | 2 | ConCall: An information service for researchers based on EdInfo In this paper, we present new types of web information services, where users and information brokers collaborate in creating a +r...#hqhf#vo/oor information service. Such services impose a novel task on information brokers: they become responsible for maintaining the inference strategies used in user modeling. In return, information brokers obtain more accurate information about user needs, since the adaptivity ensures that user profiles are kept up to date and consistent with what users actually prefer, not only what they say that they prefer. We illustrate the approach by an example application, in which conference calls are collected and distributed to interested readers. Keywords Adaptive Information Services, Intelligent Information Filtering, Agents, WWW, Adaptivity, User Modeling, User Profiling. INTRODUCTION The rapid development of information sources such as the World Wide Web has left readers with an acute problem of information overflow. The problem is not simply one ... | [
1609,
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2,008 | 4 | When Cyborgs Meet: Building Communities of Cooperating Wearable Agents This paper ... Keywords Wearable computing, personal agents, ... 1 INTRODUCTION Our modern world/society is characterized by an ever increasing ubiquity/pervasiveness of electronic communication technologies like phone and email. Despite this fact, most human interactions still occur when we physically meet other people. Every day, we encounter a large number of people - friends, colleagues and strangers alike. At places like coffee shops, grocery stores, and offices we interact with people to trade news, tell stories, gossip or exchange goods and services. Often we use these situations 1 to pursue our own goals. For example, we purchase items, coordinate schedules, or make other arrangements when we meet other people. Wearable computers provide a chance to augment such human every-day interactions and to advance cooperation (Why? Features of wearables: always on, always active, senses environment, proactive -- ability to support user during every-day life, ability to act as use... | [
1994,
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] | Train |
2,009 | 4 | Usability Engineering for Virtual Environments through a Framework of Usability Characteristics The goal of much work in virtual environments (VEs) to date has been to produce innovative visual, aural, and haptic technology; until recently, there has been very little user-centered, usability-focused research in VEs. However, there is beginning to be at least some awareness of the need for usability engineering within the VE community, mostly addressing particular parts of the VE usability space. This paper motivates the need for usability engineering methods specifically for VEs and describes a framework of usability characteristics for VEs. It gives a detailed example of use of the framework and supplemental VE usability resources in design and evaluation of a navigation metaphor for a real-world battlefield visualization VE application. Our goal is to increase awareness of the need for VE usability through this framework, which in turn will be used to produce usability engineering methods for development of VEs. KEYWORDS: Virtual environments, virtual reality, usability, usabil... | [
1793,
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2,010 | 1 | An Evolutionary Approach to Case Adaptation . We present a case adaptation method that employs ideas from the field of genetic algorithms. Two types of adaptations, case combination and case mutation, are used to evolve variations on the contents of retrieved cases until a satisfactory solution is found for a new specified problem. A solution is satisfactory if it matches the specified requirements and does not violate any constraints imposed by the domain of applicability. We have implemented our ideas in a computational system called GENCAD, applied to the layout design of residences such that they conform to the principles of feng shui, the Chinese art of placement. This implementation allows us to evaluate the use of GA's for case adaptation in CBR. Experimental results show the role of representation and constraints. 1 Introduction Many different methods have been proposed for performing the task of case adaptation in CBR. They have been surveyed in several publications, including [1], [2], and [3]. Different approaches ma... | [
46
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2,011 | 1 | A Case Study on Case-Based and Symbolic Learning (Extended Abstract) ) Stefan Wess and Christoph Globig University of Kaiserslautern, P.O. Box 3049 D-67653 Kaiserslautern, Germany fwess, globigg@informatik.uni-kl.de Abstract Contrary to symbolic learning approaches, which represent a learned concept explicitly, case-based approaches describe concepts implicitly by a pair (CB;sim), i.e. by a measure of similarity sim and a set CB of cases. This poses the question if there are any differences concerning the learning power of the two approaches. In this article we will study the relationship between the case base, the measure of similarity, and the target concept of the learning process. To do so, we transform a simple symbolic learning algorithm (the version space algorithm) into an equivalent case-based variant. The achieved results strengthen the hypothesis of the equivalence of the learning power of symbolic and case-based methods and show the interdependency between the measure used by a case-based algorithm and the target concept. Introduction I... | [
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2,012 | 4 | A Survey and Taxonomy of Location Systems for Ubiquitous Computing Emerging mobile computing applications often need to know where things are physically located. To meet this need, many di#erent location systems and technologies have been developed. In this paper we present a the basic techniques used for location-sensing, describe a taxonomy of location system properties, present a survey of research and commercial location systems that define the field, show how the taxonomy can be used to evaluate location-sensing systems, and o#er suggestions for future research. It is our hope that this paper is a useful reference for researchers and location-aware application builders alike for understanding and evaluating the many options in this domain. 1 | [
1772,
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2,013 | 1 | Automatic generation of fuzzy logic rule bases: Examples I Learning fuzzy rule-based systems with genetic algorithms can lead to very useful descriptions of several problems. Many different alternative descriptions can be generated. In many cases, a simple rule base similar to rule bases designed by humans is preferable since it has a higher possibility of being valid in unforeseen cases. Thus, the main idea of this paper is to study the genetic fuzzy rule base learning algorithm FRBL [1] by examples from the machine learning repository [2] and to compare it with some other approaches. | [
1908
] | Validation |
2,014 | 4 | The personal interaction panel - a two-handed interface for augmented reality This paper describes the introduction of a new interaction paradigm to augmented reality applications. The everyday tool handling experience of working with pen and notebooks is extended to create a three dimensional two-handed interface, that supports easy-to-understand manipulation tasks in augmented and virtual environments. In the design step we take advantage from the freedom, given by our very low demands on hardware and augment form and functionality to this device. On the basis of examples from object manipulation, augmented research environments and scientific visualization we show the generality of applicability. Although being in the first stages implementation, we consider the wide spectrum of suitability for different purposes. | [
79
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2,015 | 5 | Improved Tracking of Multiple Humans with Trajectory Prediction and Occlusion Modeling A combined 2D, 3D approach is presented that allows for robust tracking of moving bodies in a given environment as observed via a single, uncalibrated video camera. Lowlevel features are often insufficient for detection, segmentation, and tracking of non-rigid moving objects. Therefore, an improved mechanism is proposed that combines lowlevel (image processing) and mid-level (recursive trajectory estimation) information obtained during the tracking process. The resulting system can segment and maintain the tracking of moving objects before, during, and after occlusion. At each frame, the system also extracts a stabilized coordinate frame of the moving objects. This stabilized frame can be used as input to motion recognition modules. The approach enables robust tracking without constraining the system to know the shape of the objects being tracked beforehand; although, some assumptions are made about the characteristics of the shape of the objects, and how they evolve with time. Experim... | [
1137,
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2,016 | 0 | Cooperation Mechanisms in a Multi-Agent Distributed Environment In the paper we present our work on design and analysis of agent cooperation in distributed systems. The work is not completed yet, so that some parts of it, especially the formal framework, should be viewed as a preliminary version. Multi-agent systems are represented by BDI-automata, i.e., asynchronous automata composed of non-deterministic agents equipped with mental attitudes like belief, desire, and intentions. These attitudes are acquired by the agents by executing so called mental actions. Behaviours of multi-agent systems are represented by prime event structures. The prime event structure when augmented with utility functions defined on the terminal nodes of the structure may be viewed as games in extensive form defined on local states rather than on global states as in the classical definition. The definition of knowledge, in our framework, captures the change of state due to action executions. A notion of local knowledge-based protocols is defined. A game theory method of backwards induction is applied in order to obtain a very natural definition of rationality in agent's behaviours. All the notions are exemplified using the running example. For this example we construct several cooperation mechanisms for the agents. A team formation mechanism is one of them. | [
654,
1724,
2894,
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] | Validation |
2,017 | 2 | Improving Collaborative Filtering with Multimedia Indexing Techniques to create User-Adapting Web Sites The Internet is evolving from a static collection of hypertext, to a rich assortment of dynamic services and products targeted at millions of Internet users. For most sites it is a crucial matter to keep a close tie between the users and the site. | [
1901
] | Train |
2,018 | 2 | Localizing and Segmenting Text in Images and Videos Many images---especially those used for page design on web pages---as well as videos contain visible text. If these text occurrences could be detected, segmented, and recognized automatically, they would be a valuable source of high-level semantics for indexing and retrieval. In this paper, we propose a novel method for localizing and segmenting text in complex images and videos. Text lines are identified by using a complex-valued multilayer feed-forward network trained to detect text at a fixed scale and position. The network's output at all scales and positions is integrated into a single text-saliency map, serving as a starting point for candidate text lines. In the case of video, these candidate text lines are refined by exploiting the temporal redundancy of text in video. Localized text lines are then scaled to a fixed height of 100 pixels and segmented into a binary image with black characters on white background. For videos, temporal redundancy is exploited to improve segmentation performance. Input images and videos can be of any size due to a true multiresolution approach. Moreover, the system is not only able to locate and segment text occurrences into large binary images, but is also able to track each text line with sub-pixel accuracy over the entire occurrence in a video, so that one text bitmap is created for all instances of that text line. Therefore, our text segmentation results can also be used for object -based video encoding such as that enabled by MPEG-4. | [
447,
1247,
1375
] | Test |
2,019 | 1 | Graph-Theoretic Clustering for Image Grouping and Retrieval Image retrieval algorithms are generally based on the assumption that visually similar images are located close to each other in the feature space. Since the feature vectors usually exist in a very high dimensional space, a parametric characterization of their distribution is impossible, so non-parametric approaches, like the k-nearest neighbor search, are used for retrieval. This paper introduces a graph--theoretic approach for image retrieval by formulating the database search as a graph clustering problem by using a constraint that retrieved images should be consistent with each other (close in the feature space) as well as being individually similar (close) to the query image. The experiments that compare retrieval precision with and without clustering showed an average precision of 0.76 after clustering, which is an improvement by 5.56% over the average precision before clustering. 1. Motivation Computing feature vectors is an essential step in image database retrieval algorithm... | [
656
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2,020 | 4 | System And Software Visualisation If the entire of what many consider to be the software visualisation field is reviewed, then this article would be much larger in size and also consist mainly of variations on the nodes and arcs theme. Because the use of the third dimension for system and software visualisation is emerging as a viable alternative for the representation of complex artefacts then it was considered much better to focus on this form of software visualisation. The previous techniques had various identified shortcomings and the space and freedom afforded by the extra dimension has the potential to be usefully employed to overcome some of these problems. Software visualisation can be seen as a specialised subset of information visualisation. This is because information visualisation is the process of creating a graphical representation of abstract, generally non-numerical, data. This is exactly what is required when trying to visualise software. The term software visualisation has many ... | [
2303
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2,021 | 0 | Social Role Awareness in Animated Agents This paper promotes social role awareness as a desirable capability of animated agents, that are by now strong affective reasoners, but otherwise often lack the social competence observed with humans. In particular, humans may easily adjust their behavior depending on their respective role in a socio-organizational setting, whereas their synthetic pendants tend to be driven mostly by attitudes, emotions, and personality. Our main contribution is the incorporation of `social filter programs' to mental models of animated agents. Those programs may qualify an agent's expression of its emotional state by the social context, thereby enhancing the agent's believability as a conversational partner or virtual teammate. Our implemented system is entirely webbased and demonstrates socially aware animated agents in an environment similar to Hayes-Roth's Cybercaf'e. Keywords believability, social agents, human-like qualities of synthetic agents, social dimension in communication, affective reaso... | [
558,
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2,022 | 3 | Eddies: Continuously Adaptive Query Processing In large federated and shared-nothing databases, resources can exhibit widely fluctuating characteristics. Assumptions made at the time a query is submitted will rarely hold throughout the duration of query processing. As a result, traditional static query optimization and execution techniques are ineffective in these environments. In this paper we introduce a query processing mechanism called an eddy, which continuously reorders operators in a query plan as it runs. We characterize the moments of symmetry during which pipelined joins can be easily reordered, and the synchronization barriers that require inputs from different sources to be coordinated. By combining eddies with appropriate join algorithms, we merge the optimization and execution phases of query processing, allowing each tuple to have a flexible ordering of the query operators. This flexibility is controlled by a combination of fluid dynamics and a simple learning algorithm. Our initial implementation demonstrates prom... | [
279,
1184,
1536,
2139,
2219,
2435
] | Validation |
2,023 | 3 | Negation in Logic and Deductive Databases This thesis studies negation in logic and deductive databases. Among other things, two kinds of negation are discussed in detail: strong negation and nonmonotonic negation. In the logic part, we have constructed a first-order logic CF 0 of strong negation with bounded quantifiers. The logic is based on constructive logics, in particular, Thomason's logic CF. However, unlike constructive logic, quantifiers in our system as in Thomason's are static rather than dynamic. For the logic CF 0 , the usual Kripke formal semantics is defined but based on situations instead of conventional possible worlds. A sound and complete axiomatic system of CF 0 is established based on the axiomatic systems of constructive logics with strong negation and Thomason's completeness proof techniques. CF 0 is proposed as the underlying logic for situation theory. Thus the connection between CF 0 and infon logic is briefly discussed. In the database part, based on the study of some main existing semant... | [
1147,
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] | Train |
2,024 | 3 | XGobi And XploRe Meet Virgis In this paper we report on a linked environment of the three programs XGobi, XploRe, and ViRGIS. While XGobi and XploRe are statistical packages that focus on dynamic statistical graphics and provide analytical statistical features, respectively, ViRGIS is a 3D Virtual Reality Geographic Information System (GIS) that allows real--time access to, and visualization of, geographic data. The XGobi/XploRe/ViRGIS environment is based on the Remote Procedure Call (RPC) technology previously developed for the ArcView/XGobi/XploRe environment. It allows linked brushing and the exchange of data and commands --- completely transparent to the user. 1. Introduction In our previous work, we developed an open software system consisting of the Geographic Information System (GIS) ArcView, the dynamic statistical graphics program XGobi, and the statistical computing environment XploRe (Symanzik, Kotter, Schmelzer, Klinke, Cook & Swayne 1998, Symanzik, Cook, Klinke & Lewin 1998). In this current projec... | [
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2,025 | 0 | Multiagent Systems Engineering: A Methodology For Analysis And Design Of Multiagent Systems ................................................................................................................................................. IX I. INTRODUCTION ........................................................................................................................................... 1 1.1 Background................................................................................................................................. 2 1.2 Problem....................................................................................................................................... 3 1.3 Goal ............................................................................................................................................ 4 1.4 Assumptions ............................................................................................................................... 4 1.5 Areas of Collaboration............................................................................. | [
1212,
1759,
2696,
2948
] | Validation |
2,026 | 4 | VIRPI: A High-Level Toolkit for Interactive Scientific Visualization in Virtual Reality . Research areas that require interactive visualization of simulation data | [
394
] | Validation |
2,027 | 0 | A Coordination Model for Agents based on Secure Spaces . Shared space coordination models such as Linda are ill-suited for structuring applications composed of erroneous or insecure components. This paper presents the Secure Object Space model. In this model, a data element can be locked with a key and is only visible to a process that presents a matching key to unlock the element. We give a precise semantics for Secure Object Space operations and discuss an implementation in Java for a mobile agent system. An implementation of the semantics that employs encryption is also outlined for use in untrusted environments. 1 Introduction Coordination languages based on shared data spaces have been around for over fifteen years. Researchers have often advocated their use for structuring distributed and concurrent systems because the mode of communication that they provide, sometimes called generative communication, is associative and uncoupled. Communication is associative in that processes do not explicitly name their communication part... | [
1902
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2,028 | 4 | Charting Past, Present and Future Research in Ubiquitous Computing The proliferation of computing into the physical world promises more than the ubiquitous availability of computing infrastructure; it suggests new paradigms of interaction inspired by constant access to information and computational capabilities. For the past decade, application-driven research in ubiquitous computing (ubicomp) has pushed three interaction themes: natural interfaces, context-aware applications, and automated capture and access. To chart a course for future research in ubiquitous computing, we review the accomplishments of these efforts and point to remaining research challenges. Research in ubiquitous computing implicitly requires addressing some notion of scale, whether in the number and type of devices, the physical space of distributed computing, or the number of people using a system. We posit a new area of applications research, everyday computing, focussed on scaling interaction with respect to time. Just as pushing the availability of computing away from the traditional desktop fundamentally changes the relationship between humans and computers, providing continuous interaction moves computing from a localized tool to a constant companion. Designing for continuous interaction requires addressing interruption and resumption of interaction, representing passages of time and providing associative storage models. Inherent | [] | Test |
2,029 | 1 | A Microeconomic View of Data Mining We present a rigorous framework, based on optimization, for evaluating data mining operations such as associations and clustering, in terms of their utility in decisionmaking. This framework leads quickly to some interesting computational problems related to sensitivity analysis, segmentation and the theory of games. Department of Computer Science, Cornell University, Ithaca NY 14853. Email: kleinber@cs.cornell.edu. Supported in part by an Alfred P. Sloan Research Fellowship and by NSF Faculty Early Career Development Award CCR-9701399. y Computer Science Division, Soda Hall, UC Berkeley, CA 94720. christos@cs.berkeley.edu z IBM Almaden Research Center, 650 Harry Road, San Jose CA 95120. pragh@almaden.ibm.com 1 Introduction Data mining is about extracting interesting patterns from raw data. There is some agreement in the literature on what qualifies as a "pattern" (association rules and correlations [1, 2, 3, 5, 6, 12, 20, 21] as well as clustering of the data points [9], are ... | [
2324
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2,030 | 0 | Applying Artificial Intelligence to Virtual Reality: Intelligent Virtual Environments Reearch into virtual environments on the one hand and artificial intelligence and artificial life on the other has largely been carried out by two different groups of people with different preoccupations and interests, but some convergence is now apparent between the two fields. Applications in which activity independent of the user takes place --- involving crowds or other agents --- are beginning to be tackled, while synthetic agents, virtual humans and computer pets are all areas in which techniqes from the two fields require strong integration. The two communities have much to learn from each other if wheels are not to be reinvented on both sides. This paper reviews the issues arising from combining artificial intelligence and artificial life techniques with those of virtual environments to produce just such intelligent virtual environments. The discussion is illustrated with examples that include environments providing knowledge to direct or assist the user rather than r... | [
620
] | Validation |
2,031 | 4 | A User Interface for Distributed Multimedia Database Querying with Mediator Supported Refinement The Delaunay MM system supports an interactive, customizable interface for querying multimedia distributed databases, like Digital Libraries. Through this interface, users select virtual document styles that cater the display of query results to their needs, while also offering transparent pre- and post-query refinement and nested querying. Delaunay MM 's virtual documents preserve context by maintaining a single customizable interface for result viewing. The advanced transparent query features rely on mediation to provide adept access to information. In this paper, we present the framework for Delaunay MM , its architecture, the user interface, and results of the first usability study. 1. INTRODUCTION With an increase in the number of users daily, the World Wide Web has become an indispensable technology. With increasingly diverse user populations and available technologies, the value of reliable searching and information navigation mechanisms is becoming more significant. The... | [
23,
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] | Train |
2,032 | 2 | ITTALKS: A Case Study in the Semantic Web and DAML . Effective use of the vast quantity of information now available on the web will require the use of "Semantic Web" markup languages such as the DARPA Agent Markup Language (DAML). Such languages will enable the automated gathering and processing of much information that is currently available but insufficiently utilized. Effectively, such languages will facilitate the integration of multi-agent systems with the existing information infrastructure. As part of our exploration of Semantic Web technology, and DAML in particular, we have constructed ITTALKS, a web-based system for automatic and intelligent notification of information technology talks. In this paper, we describe the ITTALKS system, and discuss the numerous ways in which the use of Semantic Web concepts and DAML extend its ability to provide an intelligent online service to both the human community and the agents assisting them. 1 | [
47,
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] | Train |
2,033 | 2 | Content-Based Book Recommending Using Learning for Text Categorization Recommender systems improve access to relevant products and information by making personalized suggestions based on previous examples of a user's likes and dislikes. Most existing recommender systems use collaborative filtering methods that base recommendations on other users' preferences. By contrast, content-based methods use information about an item itself to make suggestions. This approach has the advantage of being able to recommend previously unrated items to users with unique interests and to provide explanations for its recommendations. We describe a content-based book recommending system that utilizes information extraction and a machine-learning algorithm for text categorization. Initial experimental results demonstrate that this approach can produce accurate recommendations. KEYWORDS: Recommender systems, information filtering, machine learning, text categorization INTRODUCTION There is a growing interest in recommender systems that suggest music, films, books, and othe... | [
1161,
1478,
1958,
2100,
2300,
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2,034 | 2 | A Memetic Algorithm With Self-Adaptive Local Search: TSP as a case study In this paper we introduce a promising hybridization scheme for a Memetic Algorithm (MA). Our MA is composed of two optimization processes, a Genetic Algorithm and a Monte Carlo method (MC). In contrast with other GA-Monte Carlo hybridized memetic algorithms, in our work the MC stage serves two purposes: -- when the population is diverse it acts like a local search procedure and -- when the population converges its goal is to diversify the search. To achieve this, the MC is self-adaptive based on observations from the underlying GA behavior; the GA controls the long-term optimization process. We present preliminary, yet statistically significant, results on the application of this approach to the TSP problem.We also comment it successful application to a molecular conformational problem: Protein Folding. | [
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2,035 | 3 | Automatic Generation of Warehouse Mediators Using an Ontology Engine Data warehouses created for dynamic scientific environments, such as genetics, face significant challenges to their long-term feasibility. One of the most significant of these is the high frequency of schema evolution resulting from both technological advances and scientific insight. Failure to quickly incorporate these modifications will quickly render the warehouse obsolete, yet each evolution requires significant effort to ensure the changes are correctly propagated. DataFoundry utilizes a mediated warehouse architecture with an ontology infrastructure to reduce the maintenance requirements of a warehouse. Among other things, the ontology is used as an information source for automatically generating mediators, the programs that transfer data between the data sources and the warehouse. The identification, definition, and representation of the metadata required to perform this task are the primary contributions of this work. 1 Introduction The DataFoundry research project at LLNL's ... | [
65,
463,
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] | Train |
2,036 | 0 | Report on SIKS course on interactive and multi-agent systems, 30 november - 4 december 1998 Contents 1 Introduction 2 2 Interactive systems 2 2.1 Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1.1 Overview development methods for interactive systems . . . . . . . . . 2 2.1.2 Prototyping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1.3 Techniques, tools, development environment, and management . . . . 2 2.2 Techniques per development stage . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.1 Task analysis and global design specification . . . . . . . . . . . . . . 3 2.2.2 Detailed-design stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.3 Scenario-based design . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.4 Evaluation criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2.5 Evaluation techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Multi-agent systems 4 3.1 Agent systems and models . . . . . . . . . . | [
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2,037 | 3 | Evolution and Revolutions in LDAP Directory Caches . LDAP directories have recently proliferated with the growth of the Internet, and are being used in a wide variety of network-based applications. In this paper, we propose the use of generalized queries, referred to as query templates, obtained by generalizing individual user queries, as the semantic basis for low overhead, high benefit LDAP directory caches for handling declarative queries. We present efficient incremental algorithms that, given a sequence of user queries, maintain a set of potentially beneficial candidate query templates, and select a subset of these candidates for admission into the directory cache. A novel feature of our algorithms is their ability to deal with overlapping query templates. Finally, we demonstrate the advantages of template caches over query caches, with an experimental study based on real data and a prototype implementation of the LDAP directory cache. 1 Introduction LDAP (Lightweight Directory Access Protocol) network directories ha... | [
1416,
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] | Train |
2,038 | 2 | DiscoWeb: Applying Link Analysis to Web Search How often does the search engine of your choice produce results that are less than satisfying, generating endless links to irrelevant pages even though those pages may contain the query keywords? How often are you given pages that tell you things you already know? While the search engines and related tools continue to make improvements in their information retrieval algorithms, for the most part they continue to ignore an essential part of the web – the links. We have found that link analysis can have significant contributions to web page retrieval from search engines, to web community discovery, and to the measurement of web page influence. It can help to rank results and find high-quality index/hub/link pages that contain links to the best sites on the topic of interest. Our work is based on research from IBM’s CLEVER project [7, 4, 6], Stanford’s Google [3], and the Web Archaeology research [2, 1] at Compaq’s Systems Research Center. These research teams have demonstrated some of the contributions that link analysis can make in the web. In our work, we have attempted to generalize and improve upon these approaches. Just as in citation analysis of published works, the most influential documents on the web will have many other documents recommending (pointing to) them. This idea underlies all link analysis efforts, from the straightforward technique of counting the number of incoming edges to a page, to the deeper eigenvector analysis used in our work and in those projects mentioned above. It turns out that the identification of “high-quality ” web pages reduces to a sparse eigenvalue of the adjacency matrix | [
124,
471,
1108,
1838,
2459,
2503,
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] | Train |
2,039 | 3 | An Intelligent Approach to Information Integration . Information sharing from multiple heterogeneous sources is a challenging issue which ranges from database to ontology areas. In this paper, we propose an intelligent approach to information integration which takes into account semantic conflicts and contradictions, caused by the lack of a common shared ontology. Our goal is to provide an integrated access to information sources, allowing a user to pose a single query and to receive a single unified answer. We propose a "semantic" approach for integration where the conceptual schema of each source is provided, adopting a common standard data model and language. Description Logics plus clustering techniques are exploited. Description Logics is used to obtain a semi-automatic generation of a Common Thesaurus (to solve semantic heterogeneities and to derive a common ontology) while clustering techniques are employed to build the global schema, i.e. the unified view of the data to be used for query processing. keywords: intelligent info... | [
537,
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] | Train |
2,040 | 4 | Visual Recognition of Hand Motion Hand gesture recognition is an active area of research in recent years, being used in various applications from deaf sign recognition systems to humanmachine interaction applications. The gesture recognition process, in general, may be divided into two stages: the motion sensing, which extracts useful data from hand motion; and the classification process, which classifies the motion sensing data as gestures. The existing vision-based gesture recognition systems extract 2-D shape and trajectory descriptors from the visual input, and classify them using various classification techniques from maximum likelihood estimation to neural networks, finite state machines, Fuzzy Associative Memory (FAM) or Hidden Markov Models (HMMs). This thesis presents the framework of the vision-based Hand Motion Understanding (HMU) system that recognises static and dynamic Australian Sign Language (Auslan) signs by extracting and classifying 3-D hand configuration data from the visual input. The HMU system is... | [
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2,041 | 0 | Impulse: Location-based Agent Assistance In the physical world, a user experiences products and places, explores physical surroundings, and participates in location-specific activities. Software agents, trapped in their electronic world, offer users valuable assistance online, for example by personalizing searches and queries. The Impulse research project at the MIT Media Lab [1] examines what happens when the rich experience of the physical world is augmented with the low search costs and information resources available through the Internet. This paper presents a subset and implementation of one aspect of the Impulse vision: a scenario demonstrating a mobile device which uses location-aware queries to digitally augment and explore the physical world. PROJECT OVERVIEW Related research on learning agents within wireless devices [6] and the combined work of wearable computing and ubiquitous computing [5] explore placing agents into our physical environment. Our work takes these previous explorations and introduces the idea of... | [
1397,
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] | Train |
2,042 | 1 | Automatic Detection of Human Faces in Natural Scene Images by Use of a Skin Color Model and of Invariant Moments We use a skin color model based on the Mahalanobis metric and a shape analysis based on invariant moments to automatically detect and locate human faces in two-dimensional natural scene images. First, color segmentation of an input image is performed by thresholding in a perceptually plausible hue-saturation color space where the effects of the variability of human skin color and the dependency of chrominance on changes in illumination are reduced. We then group regions of the resulting binary image which have been classified as face candidates into clusters of connected pixels. Performing median filtering on the image and discarding the smallest remaining clusters ensures that only a small number of clusters will be used for further analysis. Fully translation-, scale- and in-plane rotation-invariant moments are calculated for each remaining cluster. Finally, in order to distinguish faces from distractors, a multilayer perceptron neural network is used with the invariant moments as the input vector. Supervised learning of the network is implemented with the backpropagation algorithm, at first for frontal views of faces. Preliminary results show the efficiency of the combination of color segmentation and of invariant moments in detecting faces with a large variety of poses and against relatively complex backgrounds. 1. | [] | Validation |
2,043 | 0 | Coordination Assistance for Mixed Human and Computational Agent Systems In many application areas (such as concurrent engineering, software development, hospital scheduling, manufacturing scheduling, and military planning), individuals are responsible for an agenda of tasks and face choices about the best way to locally handle each task, in what order to do tasks, and when to do them. Such decisions are often hard to make because of coordination problems: individual tasks are related to the tasks of others in complex ways, and there are many sources of uncertainty (no one has a complete view of the task structure at arbitrary levels of detail, the situation may be changing dynamically, and no one is entirely sure of the outcomes of all of their actions). The focus of this paper is the development of support tools for distributed, cooperative work by groups (collaborative teams) of human and computational agents. We will discuss the design of a set of distributed autonomous computer programs ("agents") that assist people in coordinating their activities by ... | [
779,
996,
1107,
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] | Train |
2,044 | 1 | Grounded Speech Communication Language is grounded in sensory-motor experience. Grounding connects concepts to the physical world enabling humans to acquire and use words and sentences in context. Currently, machines which process text and spoken language are not grounded in human-like ways. Instead, semantic representations in machines are highly abstract and have meaning only when interpreted by humans. We are interested in developing computational systems which represent words, utterances, and underlying concepts in terms of sensory-motor experiences, leading to richer levels of understanding by machines. Inspired by theories of infant cognition, we present a computational model which learns from untranscribed multisensory input. Acquired words are represented in terms associations between acoustic and visual sensory experience. The system has been tested in a robotic embodiment which supports interactive language learning and understanding. Successful learning has also been demonstrated using infant -directed s... | [
1986
] | Train |
2,045 | 0 | Temporal Requirements for Anticipatory Reasoning about Intentional Dynamics in Social Contexts Abstract In this paper a temporal trace language is defined in which formulae can be expressed that provide an external temporal grounding of intentional notions. Justifying conditions are presented that formalise criteria that a (candidate) formula must satisfy in order to qualify as an external representation of a belief, desire or intention. Using these conditions, external represenation formulae for intentional notions can be identified. Using these external representations, anticipatory reasoning about intentional dynamics can be performed. 1 | [
555
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2,046 | 1 | Data-Driven Theory Refinement Using KBDistAl Knowledge based artificial neural networks offer an attractive approach to extending or modifying incomplete knowledge bases or domain theories through a process of data-driven theory refinement. We present an efficient algorithm for data-driven knowledge discovery and theory refinement using DistAl, a novel (inter-pattern distance based, polynomial time) constructive neural network learning algorithm. The initial domain theory comprising of propositional rules is translated into a knowledge based network. The domain theory is modified using DistAl which adds new neurons to the existing network as needed to reduce classification errors associated with the incomplete domain theory on labeled training examples. The proposed algorithm is capable of handling patterns represented using binary, nominal, as well as numeric (real-valued) attributes. Results of experiments on several datasets for financial advisor and the human genome project indicate that the performance of the proposed algorithm compares quite favorably with other algorithms for connectionist theory refinement (including those that require substantially more computational resources) both in terms of generalization accuracy and network size. | [
1808,
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2,047 | 1 | Incremental Evolution of Neural Controllers for Navigation in a 6-legged Robot This paper describes how the SGOCE paradigm has been used within the context of a "minimal simulation " strategy to evolve neural networks controlling locomotion and obstacle-avoidance in a 6-legged robot. Such controllers have been first evolved through simulation and then successfully downloaded on the real robot. | [
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2,048 | 1 | Case-Based Learning: Beyond Classification of Feature Vectors . The dominant theme of case-based research at recent ML conferences has been on classifying cases represented by feature vectors. However, other useful tasks can be targeted, and other representations are often preferable. We review the recent literature on case-based learning, focusing on alternative performance tasks and more expressive case representations. We also highlight topics in need of additional research. 1 Introduction The majority of machine learning (ML) research has focussed on supervised learning tasks in which class-labeled cases, each represented as a vector of features, are given to a learning algorithm that induces a concept description. This description can then be used to predict the class labels of unlabeled cases. One approach for solving supervised learning tasks, called case-based, 3 involves storing cases, often as hproblem,solutioni pairs, and retrieving them to solve similar problems. This distinguishes their behavior from approaches that greedily repla... | [
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] | Train |
2,049 | 4 | Running the Web Backwards: Appliance Data Services Appliance" digital devices such as handheld cameras, scanners, and microphones generate data that people want to put on Web pages. Unfortunately, numerous complex steps are required. Contrast this with Web output: handheld web browsers enjoy increasing infrastructural support such as user-transparent transformation proxies, allowing unmodified Web pages to be conveniently viewed on devices not originally designed for the task. We hypothesize that the utility of input appliances will be greatly increased if they too were "infrastructure enabled." Appliance Data Services attempts to systematically describe the task domain of providing seamless and graceful interoperability between input appliances and the Web. We offer an application architecture and a validating prototype that we hope will "open up the playing field" and motivate further work. Our initial efforts have identified two main design challenges: dealing with device heterogeneity, and providing a "no-futz" out-of-the-box user experience for novices without sacrificing expressive power for advanced users. We address heterogeneity by isolating device and protocol heterogeneity considerations into a single extensible architectural component, allowing most of the application logic to deal exclusively with Web-friendly protocols and formats. We address the user interface issue in two ways: first, by specifying how to tag input with commands that specify how data is to be manipulated once injected into the infrastructure; second, by describing a late-binding mechanism for these command tags, which allows "natural" extensions of the device's UI for application selection and minimizes the amount of configuration required before end-users benefit from Appliance Data Services. Finally, we describe how to leverage existi... | [
2194,
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] | Test |
2,050 | 3 | Towards an Accommodation of Delay in Temporal Active Databases Business rules can be formulated according to the eventcondition -action structure of triggers in active databases. However, delays in the execution of such rules can cause unexpected and undesired side-effects. While business rules are commonly constructed from an external user's perspective, users often neglect to cater for the cases in which unanticipated sequences of I/O and rule activation events occur. This paper examines this issue from the perspective of temporal databases and discusses a framework for accommodating delay in rule activation. In order to do this the paper also outlines a flexible technique to ensure correct transaction sequencing in transaction-time databases. 1 Introduction Active database systems allow users to specify business rules, commonly in terms of (sets of) event-condition-action (E-C-A) triplets that specify that certain actions should be invoked when certain events occur and certain conditions hold [17]. Such rules are useful in providing an active... | [
938,
1055
] | Validation |
2,051 | 2 | Indexing and Retrieving Natural Language Using Ternary Expressions Traditional information retrieval systems based on the "bag-of-words" paradigm cannot completely capture the semantic content of documents. Yet it is impossible with current technology to build a practical information access system that fully analyzes and understands unrestricted natural language. However, if we avoid the most complex and processing-intensive natural language understanding techniques, we can construct a large-scale information access system which is capable of processing unrestricted text, largely understanding it, and answering natural language queries with high precision. We believe that ternary expressions are the most suitable representational structure for such a system; they are expressive enough for information retrieval purposes, yet amenable to rapid large-scale indexing. | [
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2,052 | 5 | Mobile Agents In Intrusion Detection And Response Effective intrusion detection capability is an elusive goal, not solved easily or with a single mechanism. However, mobile software agents go a long way toward realizing the ideal behavior desired in an Intrusion Detection System (IDS). This paper is an initial look at the relatively unexplored terrain of using mobile agents for intrusion detection and response. It looks not only at the benefits derived from mobility, but also those associated with software agent technology. We explore these benefits in some detail and propose a number of innovative ways to apply agent mobility to address the shortcomings of current IDS designs and implementations. We also look at new approaches for automating response to an intrusion, once detected. 1 Appeared in the proceedings of the 12th Annual Canadian Information Technology Security Symposium, Ottawa, Canada, June 2000. MOBILE AGENTS IN INTRUSION DETECTION AND RESPONSE 1 MOBILE AGENTS IN INTRUSION DETECTION AND RESPONSE Background Intrusion... | [
173,
896,
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] | Test |
2,053 | 5 | On the Knowledge Requirements of Tasks In order to successfully perform a task, a situated system requires some information about its domain. If we can understand what information the system requires, we may be able to equip it with more suitable sensors or make better use of the information available to it. These considerations have motivated roboticists to examine the issue of sensor design, and in particular, the minimal information required to perform a task. We show here that reasoning in terms of what the robot knows and needs to know to perform a task is a useful approach for analyzing these issues. We extend the formal framework for reasoning about knowledge, already used in AI and distributed computing, by developing a set of basic concepts and tools for modeling and analyzing the knowledge requirements of tasks. We investigate properties of the resulting framework, and show how it can be applied to robotics tasks. 1 Introduction The notion of computational complexity has had a profound effect on the development o... | [
3146
] | Train |
2,054 | 2 | An Integrated Ontology for the WWW . Knowledge-intensive processing of WWW information should be founded on clear and uniform conceptualisation. An integrated ontology covering different aspects of the WWW (documents, sites, network addressing, HTML code) has been laid down, upon which a knowledge base of the WWW domain is being built. This knowledge base should support "intelligent" metasearch of the Web, in particular, postprocessing of hit-lists returned by external search engines. 1 Introduction During the last few years, the World-Wide Web has become one of the most widespread technologies of information presentation. It is thus not surprising that many Knowledge Engineering (KE) projects focus on it: some use HTML as a cheap, ready-made user-interface, other thrive to mine valuable information hidden inside existing WWW pages. A necessary prerequisite of mutual comprehensibility and knowledge reuse among different KE communities and projects dealing with the Web is a clear and unified conceptualisation, wh... | [
759,
901,
2665,
2918
] | Train |
2,055 | 2 | Signal Detection Using ICA: Application to Chat Room Topic Spotting Signal detection and pattern recognition for online grouping huge amounts of data and retrospective analysis is becoming increasingly important as knowledge based standards, such as XML and advanced MPEG, gain popularity. Independent component analysis (ICA) can be used to both cluster and detect signals with weak a priori assumptions in multimedia contexts. ICA of real world data is typically performed without knowledge of the number of non-trivial independent components, hence, it is of interest to test hypotheses concerning the number of components or simply to test whether a given set of components is significant relative to a "white noise" null hypothesis. It was recently proposed to use the so-called Bayesian information criterion (BIC) approximation, for estimation of such probabilities of competing hypotheses. Here, we apply this approach to the understanding of chat. We show that ICA can detect meaningful context structures in a chat room log file. 1. | [
878,
1386,
2889
] | Train |
2,056 | 0 | Using Multi-Context Systems to Engineer Executable Agents In the area of agent-based computing there are many proposals for specific system architectures, and a number of proposals for general approaches to building agents. As yet, however, there are few attempts to relate these together, and even fewer attempts to provide methodologies which relate designs to architectures and then to executable agents. This paper provides a first attempt to address this shortcoming; we propose a general method of defining architectures for logic-based agents which can be directly executed. Our approach is based upon the use of multi-context systems and we illustrate its use with an example architecture capable of argumentation-based negotiation. 1 Introduction Agent-based computing is fast emerging as a new paradigm for engineering complex, distributed systems [13, 27]. An important aspect of this trend is the use of agent architectures as a means of delivering agent-based functionality (cf. work on agent programming languages [14, 23, 25]). In t... | [
566,
1260,
1724,
2243
] | Train |
2,057 | 2 | Learning to Recommend from Positive Evidence In recent years, many systems and approaches for recommending information, products or other objects have been developed. In these systems, often machine learning methods that need training input to acquire a user interest profile are used. Such methods typically need positive and negative evidence of the user’s interests. To obtain both kinds of evidence, many systems make users rate relevant objects explicitly. Others merely observe the user’s behavior, which fairly obviously yields positive evidence; in order to be able to apply the standard learning methods, these systems mostly use heuristics that attempt to find also negative evidence in observed behavior. In this paper, we present several approaches to learning interest profiles from positive evidence only, as it is contained in observed user behavior. Thus, both the problem of interrupting the user for ratings and the problem of somewhat artificially determining negative evidence are avoided. The learning approaches were developed and tested in the context of the Web-based ELFI information system. It is in real use by more than 1000 people. We give a brief sketch of ELFI and describe the experiments we made based on ELFI usage logs to evaluate the different proposed methods. | [
544,
2968
] | Validation |
2,058 | 0 | Multi-agent Systems as Intelligent Virtual Environments Intelligent agent systems have been the subject of intensive research over the past few years; they comprise one of the most promising computing approaches ever, able to address issues that require abstract modelling and higher level reasoning. Virtual environments, on the other hand, offer the ideal means to produce simulations of the real world for purposes of entertainment, education, and others. The merging of these two fields seems to have a lot to offer to both research and applications, if progress is made on a co-ordinated manner and towards standardization. This paper is a presentation of VITAL, an intelligent multi-agent system able to support general-purpose intelligent virtual environment applications. | [
214
] | Train |
2,059 | 3 | Normal Forms and Proofs in Combined Modal and Temporal Logics . In this paper we present a framework for the combination of modal and temporal logic. This framework allows us to combine different normal forms, in particular, a separated normal form for temporal logic and a first-order clausal form for modal logics. The calculus of the framework consists of temporal resolution rules and standard first-order resolution rules. We show that the calculus provides a sound, complete, and terminating inference systems for arbitrary combinations of subsystems of multimodal S5 with linear, temporal logic. 1 | [
84,
183,
353,
712
] | Train |
2,060 | 3 | DataBlitz Storage Manager: Main-Memory Database Performance for Critical Applications Introduction General-purpose commercial disk-based database systems, though widely employed in practice, have failed to meet the performance requirements of applications requiring short, predictable response times, and extremely high throughput rates. Main memory is the only technology capable of these characteristics. DataBlitz 1 is a main-memory storage manager product that supports the development of high-performance and fault-resilient applications requiring concurrent access to shared data. In DataBlitz, core algorithms for concurrency, recovery, index management and space management are optimized for the case that data is memory resident. 2 DataBlitz Architecture and Features In this section, we give a high-level overview of the architecture and features of the DataBlitz Storage Manager product implemented at Bell Laboratories (for more details, see [1]). Direct Access to Data. DataBlitz is designed to a | [
1196
] | Test |
2,061 | 1 | Approximating the non-dominated front using the Pareto Archived Evolution Strategy We introduce a simple evolution scheme for multiobjective optimization problems, called the Pareto Archived Evolution Strategy (PAES). We argue that PAES may represent the simplest possible nontrivial algorithm capable of generating diverse solutions in the Pareto optimal set. The algorithm, in its simplest form, is a (1 + 1) evolution strategy employing local search but using a reference archive of previously found solutions in order to identify the approximate dominance ranking of the current and candidate solution vectors. (1 + 1)-PAES is intended to be a baseline approach against which more involved methods may be compared. It may also serve well in some real-world applications when local search seems superior to or competitive with population-based methods. We introduce (1 + λ) and (μ | λ) variants of PAES as extensions to the basic algorithm. Six variants of PAES are compared to variants of the Niched Pareto Genetic Algorithm and the Nondominated Sorting Genetic Algorithm over a diverse suite of six test functions. Results are analyzed and presented using techniques that reduce the attainment surfaces generated from several optimization runs into a set of univariate distributions. This allows standard statistical analysis to be carried out for comparative purposes. Our results provide strong evidence that PAES performs consistently well on a range of multiobjective optimization tasks. | [
652,
1359
] | Validation |
2,062 | 1 | Introducing a Two-Level Grammar Concept for Design (Extended Abstract) this paper. A few investigation may first illustrate the differences of our new concepts from known hierarchies. Even if L(G) is regular, L(DG) may be not context-free. There is no need for a proof as it is folklore that pattern languages are usually not context-free. We present a few further trivialities to warm up: In case j V j = 1, L(DG) is regular if and only if L(G) is regular. If T 1 and T 2 are disjoint, it holds: 1. Membership for L(DG) is uniformly decidable. 2. Emptyness for L(DG) is uniformly decidable. 3. Finiteness for L(DG) is uniformly decidable. There is no need for an explicit proof. The results above are immediately inherited from classical results in formal language theory (cf. [HU79]). Further properties seem to require particular assumptions. For the intended application domain, languages which satisfy T 1 n T 2 6= ; are of a particular importance. It may also be of a special interest to consider languages with a certain rate of letters from T 1 n T 2 in terminal words. 3.2 Graph Grammars | [
636
] | Train |
2,063 | 0 | Intention Reconsideration in Complex Environments One of the key problems in the design of belief-desire-intention (BDI) agents is that of finding an appropriate policy for intention reconsideration. In previous work, Kinny and Georgeff investigated the effectiveness of several such reconsideration policies, and demonstrated that in general, there is no one best approach -- different environments demand different intention reconsideration strategies. In this paper, we further investigate the relationship between the effectiveness of an agent and its intention reconsideration policy in different environments. We empirically evaluate the performance of different reconsideration strategies in environments that are to varying degrees dynamic, inaccessible, and nondeterministic. In addition to our empirical results, we are able to give preliminary analytical results to explain some of our findings. | [
1662,
2400,
2813,
3128
] | Validation |
2,064 | 4 | Http://www.playresearch.com/ this report. The following link takes you directly to a page with links to the core publications and other evaluation material in PDF format: | [
450,
457,
798,
1776,
2913
] | Test |
2,065 | 1 | Ant Colony Optimisation for Virtual-Wavelength-Path Routing and Wavelength Allocation Ant Colony Optimisation (ACO) is applied to the problem of routing and wavelength-allocation in a multi-wavelength all-optical virtual-wavelength-path routed transport network. Three variants of our ACO algorithm are proposed: local update (LU), global update/ distance (GU/D) and global update/occupancy (GU/O). All three extend the usual practice that ants are attracted by the pheromone trail of ants from their own colony: in our work, the artificial ants are also repelled by the pheromone of other colonies. Overall, the best ACO variant, GU/O, provides results that approach those of an earlier problem-specific heuristic on small- and medium-sized networks. 1 Introduction Multi-wavelength all-optical transport networks have attracted considerable interest in recent years, because of their potential, by using multiple wavelengths in both optical transmission and optical switching, to provide the huge bandwidths necessary if broadband services are to be widely adopted [1]. In addition,... | [
86,
234,
1745
] | Test |
2,066 | 0 | Embodied Evolution: Embodying an Evolutionary Algorithm in a Population of Robots We introduce Embodied Evolution (EE) as a methodology for the automatic design of robotic controllers. EE is an evolutionary robotics (ER) technique that avoids the pitfalls of the simulate-and-transfer method, allows the speed-up of evaluation time by utilizing parallelism, and is particularly suited to future work on multi-agent behaviors. In EE, an evolutionary algorithm is distributed amongst and embodied within a population of physical robots that reproduce with one another while situated in the task environment. We have built a population of eight robots and successfully implemented our first experiments. The controllers evolved by EE compare favorably to hand-designed solutions for a simple task. We detail our methodology, report our initial results, and discuss the application of EE to more advanced and distributed robotics tasks. 1. Introduction Our work is inspired by the following vision. A large number of robots freely interact with each other in a shared environment, atte... | [
1764
] | Train |
2,067 | 1 | Empirical Performance Analysis of Linear Discriminant Classifiers In face recognition literature, holistic template matching systems and geometrical local feature based systems have been pursued . In the holistic approach, PCA (Principal Component Analysis) and LDA (Linear Discriminant Analysis) are popular ones. More recently, the combination of PCA and LDA has been proposed as a superior alternative over pure PCA and LDA. In this paper, we illustrate the rationales behind these methods and the pros and cons of applying them to pattern classification task. A theoretical performance analysis of LDA suggests applying LDA over the principal components from the original signal space or the subspace. The improved performance of this combined approach is demonstrated through experiments conducted on both simulated data and real data. 1 Introduction Statistical pattern recognition techniques have been successfully applied to many problems, including speech recognition, automatic target recognition and image classification. For a given pattern classificat... | [
2174,
3058
] | Train |
2,068 | 2 | Learning Information Extraction Rules for Semi-structured and Free Text . A wealth of on-line text information can be made available to automatic processing by information extraction (IE) systems. Each IE application needs a separate set of rules tuned to the domain and writing style. WHISK helps to overcome this knowledge-engineering bottleneck by learning text extraction rules automatically. WHISK is designed to handle text styles ranging from highly structured to free text, including text that is neither rigidly formatted nor composed of grammatical sentences. Such semistructured text has largely been beyond the scope of previous systems. When used in conjunction with a syntactic analyzer and semantic tagging, WHISK can also handle extraction from free text such as news stories. Keywords: natural language processing, information extraction, rule learning 1. Information extraction As more and more text becomes available on-line, there is a growing need for systems that extract information automatically from text data. An information extraction (IE) sys... | [
47,
156,
255,
327,
434,
529,
710,
714,
721,
786,
801,
815,
875,
906,
1108,
1294,
1527,
1684,
2676,
2961,
3098,
3099,
3152
] | Train |
2,069 | 4 | Whole-Hand and Speech Input in Virtual Environments Recent approaches to providing users with a more natural method of interacting with computer applications have shown that more than one mode of input can be both beneficial and intuitive as a communication medium between humans and computers. Two modalities in particular, whole-hand and speech input, represent a natural form of communication that has been ingrained in our physical and mental makeup since birth. In this thesis, we investigate the use of whole-hand and speech input in virtual environments in the context of two applications domains: scientific visualization and interior design. By examining the two modalities individually and in combination, and through the creation of two application prototypes (Multimodal Scientific Visualization Tool and Room Designer), we present anumber of contributions including a set of interface guidelines and interaction techniques for whole-hand and speech input. | [
257,
481,
790,
1584
] | Train |
2,070 | 1 | Online Learning with Random Representations We consider the requirements of online learning---learning which must be done incrementally and in realtime, with the results of learning available soon after each new example is acquired. Despite the abundance of methods for learning from examples, there are few that can be used effectively for online learning, e.g., as components of reinforcement learning systems. Most of these few, including radial basis functions, CMACs, Kohonen 's self-organizing maps, and those developed in this paper, share the same structure. All expand the original input representation into a higher dimensional representation in an unsupervised way, and then map that representation to the final answer using a relatively simple supervised learner, such as a perceptron or LMS rule. Such structures learn very rapidly and reliably, but have been thought either to scale poorly or to require extensive domain knowledge. To the contrary, some researchers (Rosenblatt, 1962; Gallant & Smith, 1987; Kanerva, 1988; Prager ... | [
1213,
2428
] | Train |
2,071 | 1 | Fast Reinforcement Learning through Eugenic Neuro-Evolution In this paper we introduce EuSANE, a novel reinforcement learning algorithm based on the SANE neuroevolution method. It uses a global search algorithm, the Eugenic Algorithm, to optimize the selection of neurons to the hidden layer of SANE networks. The performance of EuSANE is evaluated in the two-pole balancing benchmark task, showing that EuSANE is significantly stronger than other reinforcement learning methods to date in this task. | [
315,
2450
] | Train |
2,072 | 1 | Fuzzy Meta-Learning: Preliminary Results Learning from distributed data is becoming in our times a necessity, but it is also a complex and challenging task. Approaches developed so far have not dealt with the uncertainty, imprecision and vagueness involved in distributed learning. Meta-Learning, a successful approach for distributed data mining, is in this paper extended to handle the imprecision and uncertainty of the local models and the vagueness that characterizes the meta-learning process. The proposed approach, Fuzzy Meta-Learning uses a fuzzy inductive algorithm to meta-learn a global model from the degrees of certainty of the output of local classifiers. This way more accurate models of collective knowledge can be acquired from data with application both to inherently distributed databases and parts of a very large database. Preliminary results are promising and encourage further research towards this direction. 1 | [
995
] | Test |
2,073 | 4 | Interacting with Spatially Augmented Reality Traditional user interfaces for off-the-desktop applications are designed to display the output on flat 2D surfaces while the input is with 2D or 3D devices. In this paper, we focus on projectorbased augmented reality applications. We describe a framework to easily incorporate the interaction on a continuum of display surfaces and input devices. We first create a 3D understanding of the relationship between the user, the projectors and the display surfaces. Then we use some new calibration and rendering techniques to create a simple procedure to effectively illuminate the surfaces. We describe various underlying techniques and discuss the results in the context of three different applications. | [
2534
] | Train |
2,074 | 2 | Validating Access to External Information Sources in a Mediator Environment A mediator integrates existing information sources into a new application. In order to answer complex queries, the mediator splits them up into sub-queries which it sends to the information sources. Afterwards, it combines the replies to answer the original query. Since the information sources are usually external, autonomous systems, the access to them can sometimes be erroneous, most notably when the information source is changed. This results in an incorrect behaviour of the whole system. The question that this paper addresses, is: how to check whether or not the access was correct? The paper introduces a notational framework for the general information access validation problem, describes the typical errors that can occur in a mediator environment, and proposes several validation mechanisms. It is also investigated how the validation functionality can be integrated into the mediator architecture, and what the most important quality measures of a validation method are. Moreover, the practical usability of the presented approaches is demonstrated on a real-world application using Web-based information sources. Several measurements are performed to compare the presented methods with previous work in the field. | [
371,
406,
529,
1398,
2503
] | Train |
2,075 | 5 | Space Discretization for Efficient Human Navigation There is a large body of research on motion control of legs in human models. However, they require specification of global paths in which to move. A method for automatically computing a global motion path for a human in 3D environment of obstacles is presented. Object space is discretized into a 3D grid of uniform cells and an optimal path is generated between two points as a discrete cell path. The grid is treated as graph with orthogonal links of uniform cost. A* search method is applied for path finding. By considering only the cells on the upper surface of objects on which human walks, a large portion of the grid is discarded from the search space, thus boosting efficiency. This is expected to be a higher level mechanism for various local foot placement methods in human animation. Keywords: global navigation, dynamic programming, A* graph search, articulated body models 1. Introduction Human walking is a complex and well studied component of articulated body animation research. T... | [
2868,
2952
] | Train |
2,076 | 4 | A Comparison of Usage Evaluation and Inspection Methods for Assessing Groupware Usability Many researchers believe that groupware can only be evaluated by studying real collaborators in their real contexts, a process that tends to be expensive and timeconsuming. Others believe that it is more practical to evaluate groupware through usability inspection methods. Deciding between these two approaches is difficult, because it is unclear how they compare in a real evaluation situation. To address this problem, we carried out a dual evaluation of a groupware system, with one evaluation applying userbased techniques, and the other using inspection methods. We compared the results from the two evaluations and concluded that, while the two methods have their own strengths, weaknesses, and trade-offs, they are complementary. Because the two methods found overlapping problems, we expect that they can be used in tandem to good effect, e.g., applying the discount method prior to a field study, with the expectation that the system deployed in the more expensive field study has a better chance of doing well because some pertinent usability problems will have already been addressed. Keywords Evaluation, groupware usability, inspection evaluation techniques, usage evaluation techniques. | [
99,
1362,
2005,
2684
] | Train |
2,077 | 5 | A Description Logic with Concrete Domains and a Role-forming Predicate Operator Description Logics (DLs) are a family of logic-based knowledge representation formalisms designed to represent and reason about conceptual knowledge. Due to a nice compromise between expressivity and the complexity of reasoning, DLs have found applications in many areas such as, e.g., modelling database schemas and the semantic web. However, description logics represent knowledge in an abstract way and lack the power to describe more concrete (quantitative) qualities like size, duration, or amounts. The standard solution is to equip DLs with concrete domains, e.g., natural numbers with predicates =, <, + or strings with a string concatenation predicate. Moreover, recently it has been suggested that the expressive power of DLs with concrete domains can be further enhanced by providing them with database-like key constraints. Key constraints can be a source of additional inconsistencies in database schemas, and DLs applied in reasoning about database schemas are thus wanted to be able to capture such constraints. Up to now, only the integration of uniqueness key constraints into DLs with concrete | [
294,
534,
2361,
3036
] | Train |
2,078 | 3 | On the Difference of Horn Theories In this paper, we consider computing the difference between two Horn theories. This problem may arise, for example, if we take care of a theory change in a knowledge base. In general, the difference of Horn theories is not Horn. Therefore, we consider Horn approximations of the difference in terms of Horn cores (i.e., weakest Horn theories included in the difference) and the Horn envelope (i.e., the strongest Horn theory containing the difference), which have been proposed and analyzed extensively in the literature. We study the problem under the familiar representation of Horn theories by Horn CNFs, as well as under the recently proposed model-based representation in terms of the characteristic models. For all problems and representations, polynomial time algorithms or proofs of intractability for the propositional case are provided; thus, our work gives a complete picture of the tractability/intractability frontier in the propositional Horn theories. | [
2406
] | Train |
2,079 | 1 | Extending Local Learners with Error-Correcting Output Codes : Error-correcting output codes (ECOCs) represent classes with a set of output bits, where each bit encodes a binary classification task corresponding to a unique partition of the classes. Algorithms that use ECOCs learn the function corresponding to each bit, and combine them to generate class predictions. ECOCs can reduce both variance and bias errors for multiclass classification tasks when the errors made at the output bits are not correlated. They work well with global (e.g., C4.5) but not with local (e.g., nearest neighbor) classifiers because the latter use the same information to predict each bit's value, which yields correlated errors. This is distressing because local learners are excellent classifiers for some types of applications. We show that the output bit errors of local learners can be decorrelated by selecting different features for each bit. This yields bit-specific distance functions, which causes different information to be used for each bit's prediction. We presen... | [
64,
1389
] | Train |
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