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180 | 2 | A Non-obtrusive User Interface for Increasing Social Awareness on the World Wide Web Arguing for the need of increasing social awareness on the World Wide Web, we describe a user interface based on the metaphor of windows bridging electronic and physical spaces. We present a system that, with the aim of making on-line activity perceptible in the physical world, makes it possible to hear people visiting one's Web site. The system takes advantage of the seamless and continuous network connection offered by handheld Web-appliances such as PDA's. | [
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181 | 4 | The Morph Node We discuss potential and limitations of a Morph Node, inspired by the corresponding construct in Java3D. A Morph Node in Java3D interpolates vertex attributes among several homeomorphic geometries. This node is a promising candidate for the delivery of 3D animation in a very compact form. We review the state-of-the-art in Web 3D techniques, allowing for the possibility of interpolating among several geometries. This review leads to a simple extension for VRML-97 as well as a recommendation for necessary changes in Java3D. Furthermore, we discuss various optimization issues for Morph Nodes. CR Categories and Subject Descriptors. I.3.6 [Computer Graphics ] Methodology and Techniques: Standards - VRML; I.3.7 [Computer Graphics] Three Dimensional Graphics and Realism: Animation; I.3.8 [Computer Graphics] Applications. Additional Keywords. Animation, Avatars, Morphing, Virtual Humans, VRML. INTRODUCTION Animation of three-dimensional shapes involves the change of vertex attributes over ... | [
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182 | 3 | HYSSOP: Natural Language Generation Meets Knowledge Discovery in Databases. In this paper, we present HYSSOP, a system that generates natural language hypertext summaries of insights resulting from a knowledge discovery process. We discuss the synergy between the two technologies underlying HYSSOP: Natural Language Generation (NLG) and Knowledge Discovery in Databases (KDD). We first highlight the advantages of natural language hypertext as a summarization medium for KDD results, showing the gains that it provides over charts and tables in terms of conciseness, expressive versatility and ease of interpretation for decision makers. Second, we highlight how KDD technologies, and in particular OLAP and data mining, can implement key tasks of automated natural language data summary generation, in a more domain-independent and scalable way than the human written heuristic rule approach of previous systems. | [
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183 | 0 | Combinations of Modal Logics Combining logics for modelling purposes has become a rapidly expanding enterprise that is inspired mainly by concerns about modularity and the wish to join together different kinds of information. As any interesting real world system is a complex, composite entity, decomposing its descriptive requirements (for design, verification, or maintenance purposes) into simpler, more restricted, reasoning tasks is not only appealing but is often the only plausible way forward. It would be an exaggeration to claim that we currently have a thorough understanding of `combined methods.' However, a core body of notions, questions and results has emerged for an important class of combined logics, and we are beginning to understand how this core theory behaves when it is applied outside this particular class. In this paper we will consider the combination of modal (including temporal) logics, identifying leading edge research that we, and others, have carried out. Such combined sys | [
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184 | 2 | Using Experience to Guide Web Server Selection We examine the use of the anycasting communication paradigm to improve client performance when accessing replicated multimedia objects. Anycasting supports dynamic selection of a server amongst a group of servers that provide equivalent content. If the selection is done well, the client will experience improved performance. A key issue in anycasting is the method used to maintain performance information used in server selection. We explore using past performance or experience to predict future performance. We conduct our work in the context of a customized web prefetching application called WebSnatcher. We examine a variety of algorithms for selecting a server using past performance and find that the overall average and weighted average algorithms are closest to optimal performance. In addition to the WebSnatcher application, this work has implications for responsible network behavior by other applications that generate network traffic automatically. By using the techniques we present ... | [
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185 | 0 | A multi-agent system for advising and monitoring students navigating instructional Web sites A growing community of teachers, at all levels of the educational system, provides course material in the form of hypertext/multimedia documents. In most cases this is done by creating a course Web site. This paper explores the issues related to the design of software systems that aid teachers in monitoring how students use their sites and proactively advise students navigating the sites. In connection to these functions two important topics in current applications of technology to education are discussed. Firstly the definition of a set of criteria allowing the evaluation of the appropriateness of multi-media and hypertext technologies vis vis to classic course support material and in particular textbooks. Secondly the issue of the utility and acceptability of proactive user interfaces such as interface agents or personal assistant agents. A multi agent system capable of advising and monitoring students navigating instructional Web sites is introduced and it is used as a basis for discussion of the above two topics. The system generates and uses a set of indicators evaluating how much use is made of hypertext and multimedia tools as well as indicators of usefulness and cognitive support of the proactive user interface. Keywords: Tutoring systems, Multi agent systems, World Wide Web, Autonomous Interface Agents, Digital Course Material, XML. 1. | [
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186 | 2 | A Theory of Term Weighting Based on Exploratory Data Analysis Techniques of exploratory data analysis are used to study the weight of evidence that the occurrence of a query term provides in support of the hypothesis that a document is relevant to an information need. In particular, the relationship between the document frequency and the weight of evidence is investigated. A correlation between document frequency normalized by collection size and the mutual information between relevance and term occurrence is uncovered. This correlation is found to be robust across a variety of query sets and document collections. Based on this relationship, a theoretical explanation of the efficacy of inverse document frequency for term weighting is developed which differs in both style and content from theories previously put forth. The theory predicts that a "flattening" of idf at both low and high frequency should result in improved retrieval performance. This altered idf formulation is tested on all TREC query sets. Retrieval results corroborate the predicti... | [
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187 | 4 | Guided by Voices: An Audio Augmented Reality System This paper presents an application of a low cost, lightweight audio-only augmented reality infrastructure. The system uses a simple wearable computer and a RF based location system to play digital sounds corresponding to the user's location and current state. Using this infrastructure we implemented a game in the fantasy genre where players move around in the real world and trigger actions in the virtual game world. We present some of the issues involved in creating audio-only augmented reality games and show how our location infrastructure is generalizable to other audio augmented realities. Keywords Audio, augmented reality, wearable computing, context-awareness INTRODUCTION This paper presents a lightweight and inexpensive infrastructure for augmented realities that uses a simple wearable computer. Whereas most traditional augmented reality systems overlay graphics onto the user's environment, this system employs only audio. Furthermore, we have created a positioning infrastruct... | [
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188 | 1 | A Rule Induction Approach to Modeling Regional Pronunciation Variation. This 1)~q)er descril)es the use of rule indue-tion techniques fi)r the mli;omatic exl;ra(:l;ion of l)honemic knowledge mM rules fl'om pairs of l:,romm(:intion lexi(:a. This (:xtra(:ted knowl-edge allows the ndat)tntion of sl)ee(:h pro(:ess-ing systelns tO regional vm'iants of a language. As a case sl;u(ty, we apply the approach to Northern Dutch and Flemish (the wtriant of Dutch spoken in Flan(lers, a t)art; of Bel-gium), based Oll C(?lex and l'bnilex, promm-clarion lexi(:a tbr Norttmrn l)utch mM Fhm,-ish, r(~sl)e(:tively. In our study, we (:omt)ar(~ l;wo rule ilMu(:tion techniques, franslbrmation-B;tsed Error-l)riven Learning ('I'I/E])I,) (Brill, 1995) mM C5.0 (Quinl~m, 1993), and (,valu-ate the extr~tct(xl knowh;dge quanl:it~l;ively (a(:-(:ura.cy) mM qualitatively (linguistic r(;levanc:e of the rules). We (:onchMe that. whereas classificntion-1)ased rule. induct;ion with C5.0 is 11101.'0 a(;(:(lr&l;e ~ th(? |;rallSt~)rnl;~l;ion l"ules le;~rne(t with TBE1)I, can 1)e more easily ini;ert)reted. 1. | [
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189 | 5 | Bringing up Robots or - The Psychology of Socially Intelligent Robots: From Theory to Implementation We discuss robotic experiments in a framework based on theories in developmental psychology. 1 Introduction Piaget's theory of cognitive development has strongly influenced many approaches in artificial intelligence and agent research. His theory has been challenged from various directions, and recent experiments have confirmed Vygotsky's belief in the essential role of social interaction and teaching as a scaffolding mechanism which is important for the child in order to reach higher levels of competence and control based on current skills. Hereby concepts are not taught directly but through social interaction, the child's experiences are re-arranged, a shared understanding develops between the child and its interaction partner. A Piagetean viewpoint sees language as a product of the cognitive development of mental representations, while Vygotsky believes that the sole primary function of language is communication with peers and adults, and that language develops exactly in this cont... | [
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190 | 2 | Routing Documents According to Style Most research on automated text categorization has focused on determining the topic of a given text. While topic is generally the main characteristic of an information need, there are other characteristics that are useful for information retrieval. In this paper we consider the problem of text categorization according to style. For example, in searching the web, we may wish to automatically determine if a given page is promotional or informative, was written by a native English speaker or not, and so on. Learning to determine the style of a document is a dual to that of determining its topic, in that those document features which capture the style of a document are precisely those which are independent of its topic. We here define the features of a document to be the frequencies of each of a set of function words and parts-of-speech triples. We then use machine learning techniques to classify documents. We test our methods on four collections of downloaded newspaper and magazine articl... | [
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191 | 1 | Boosting the Margin: A New Explanation for the Effectiveness of Voting Methods Abstract. One of the surprising recurring phenomena observed in experiments with boosting is that the test error of the generated hypothesis usually does not increase as its size becomes very large, and often is observed to decrease even after the training error reaches zero. In this paper, we show that this phenomenon is related to the distribution of margins of the training examples with respect to the generated voting classification rule, where the margin of an example is simply the difference between the number of correct votes and the maximum number of votes received by any incorrect label. We show that techniques used in the analysis of Vapnik’s support vector classifiers and of neural networks with small weights can be applied to voting methods to relate the margin distribution to the test error. We also show theoretically and experimentally that boosting is especially effective at increasing the margins of the training examples. Finally, we compare our explanation to those based on the bias-variance decomposition. 1 | [
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192 | 5 | Mining Constrained Association Rules to Predict Heart Disease This work describes our experiences on discovering association rules in medical data to predict heart disease. We focus on two aspects in this work: mapping medical data to a transaction format suitable for mining association rules and identifying useful constraints. Based on these aspects we introduce an improved algorithm to discover constrained association rules. We present an experimental section explaining several interesting discovered rules. 1. | [
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193 | 2 | A World Wide Web Meta Search Engine Using an Automatic Query Routing Algorithm CONTENTS 1. INTRODUCTION......................................................... ........................................ 6 2. LITERATURE REVIEW............................................................... ........................ 9 2.1 Overview of conventional search techniques............................................. 9 2.2 Conventional query routing systems......................................................... 11 2.2.1 Manual query routing services......................................................... 11 2.2.2 Automated query routing systems based on centroids..................... 12 2.2.3 Automated query routing systems without centroids....................... 12 3. SYSTEM STRUCTURE............................................................ .......................... 14 3.1 System overview............................................................. .......................... 14 3.2 Off-line operations....................................................... | [
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194 | 1 | Optimization and Global Minimization Methods Suitable for Neural Networks Neural networks are usually trained using local, gradient-based procedures. Such methods frequently find suboptimal solutions being trapped in local minima. Optimization of neural structures and global minimization methods applied to network cost functions have strong influence on all aspects of network performance. Recently genetic algorithms are frequently combined with neural methods to select best architectures and avoid drawbacks of local minimization methods. Many other global minimization methods are suitable for that purpose, although they are used rather rarely in this context. This paper provides a survey of such global methods, including some aspects of genetic algorithms. CONTENTS 1 Introduction 2 2 Monte Carlo and its improvements 4 3 Simulated annealing and its variants 6 3.1 Adaptive Simulated Annealing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2 Alopex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... | [
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195 | 1 | Advanced DeInterlacing techniques with the use of Zonal Based Algorithms This paper describes a new highly efficient aleinterlacing approach based on motion estimation and compensation techniques. The proposed technique mainly benefits from the motion vector properties of zonal based algorithms, such as the Advanced Predictive Diamond Zonal Search (APDZS) and the Predictive Motion Vector Field Adaptive Search Technique (PMVFAST), multihypothesis motion compensation, but also an additional motion classification phase where, depending on the motion of a pixel, additional spatial and temporal information is also considered to further improve performance. Extensive simulations demonstrate the efficacy of these algorithms, especially when compared to standard deinterlacing techniques such as the line doubling and line averaging algorithms. | [
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196 | 4 | LivingLab: A white paper The LivingLab is a planned research infrastructure that is pivotal for user-system interaction research in the next decade. This article presents the concept and outlines a research programme that will be served by this facility. These future plans are motivated by a vision of future developments concerning interaction with intelligent environments. | [
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197 | 1 | Continuous State Space Q-Learning for Control of Nonlinear Systems Contents 1 Introduction 1 1.1 Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.1 Designing the state feedback controller . . . . . . . . . . . . . . . . 3 1.1.2 Unknown systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Reinforcement Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.4 Overview of this Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2 Reinforcement Learning 11 2.1 A Discrete Deterministic Optimal Control Task . . . . . . . . . . . . . . . 11 2.1.1 The problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1.2 The solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.2 The Stochastic Optimization Tasks . . . . . . . . . . . . . . . . . . . . . . 13 2.2.1 The Markov Decision Process . . . . . . . . . . . . . . . . . . . | [
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198 | 0 | Analysis and Design of Multiagent Systems Using Hybrid Coordination Media Over the last few years, two advances in agent-oriented software engineering have had a significant impact. The first is the identification of interaction and coordination as the central focus of multiagent systems design and the second is the realization that the multiagent organization is distinct from the individual agents that populate the system. Also, the evolution of new, more powerful hybrid coordination models, which combine data-centered and control-centered coordination approaches, have given us the capability to model and implement the rules that govern organizations independently from the individual agents in the system. This paper investigates how to combine the power of these hybrid coordination capabilities with the concept of organizational rules using traditional conversation-based approaches to designing multiagent systems. 1. | [
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199 | 0 | Multiple-Agent Probabilistic Pursuit-Evasion Games In this paper we develop a probabilistic framework for pursuit-evasion games. We propose a "greedy" policy to control a swarm of autonomous agents in the pursuit of one or several evaders. At each instant of time this policy directs the pursuers to the locations that maximize the probability of finding an evader at that particular time instant. It is shown that, under mild assumptions, this policy guarantees that an evader is found in finite time and that the expected time needed to find the evader is also finite. Simulations are included to illustrate the results. 1 Introduction This paper addresses the problem of controlling a swarm of autonomous agents in the pursuit of one or several evaders. To this effect we develop a probabilistic framework for pursuit-evasion games involving multiple agents. The problem is nondeterministic because the motions of the pursuers/evaders and the devices they use to sense their surroundings require probabilistic models. It is also assumed that when ... | [] | Train |
200 | 4 | Let's Browse: A Collaborative Browsing Agent Web browsing, like most of today's desktop applications, is usually a solitary activity. Other forms of media, such as watching television, are often done by groups of people, such as families or friends. What would it be like to do collaborative Web browsing? Could the computer provide assistance to group browsing by trying to help find mutual interests among the participants? Let's Browse is an experiment in building an agent to assist a group of people in browsing, by suggesting new material likely to be of common interest. It is built as an extension to the single user Web browsing agent Letizia. Let's Browse features automatic detection of the presence of users, automated "channel surfing" browsing, and dynamic display of the user profiles and explanation of recommendations. # 1999 Elsevier Science B.V. All rights reserved. Keywords: Browsing; Collaboration; Agents; User profiles 1. Collaborative browsing Increasingly, Web browsing will be performed in collaborative settings, ... | [
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201 | 3 | Typechecking for XML Transformers We study the typechecking problem for XML transformers: given an XML transformation program and a DTD for the input XML documents, check whether every result of the program conforms to a specified output DTD. We model XML transformers using a novel device called a k- pebble transducer, that can express most queries without data-value joins in XML-QL, XSLT, and other XML query languages. Types are modeled by regular tree languages, a robust extension of DTDs. The main result of the paper is that typechecking for k-pebble transducers is decidable. Consequently, typechecking can be performed for a broad range of XML transformation languages, including XMLQL and a fragment of XSLT. 1. INTRODUCTION Traditionally, database query languages have focused on data retrieval, with complex data transformations left to applications. The new XML data exchange standard for the Web, and emerging applications requiring data wrapping and integration, have shifted the focus towards data transformations.... | [
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202 | 5 | BISMARC: A Biologically Inspired System for Map-based Autonomous Rover Control As the complexity of the missions to planetary surfaces increases, so too does the need for autonomous rover systems. This need is complicated by the power, mass and computer storage restrictions on such systems (Miller, 1992). To address these problems, we have recently developed a system called BISMARC (Biologically Inspired System for Map-based Autonomous Rover Control) for planetary missions involving multiple small, lightweight surface rovers (Huntsberger, 1997). BISMARC is capable of cooperative planetary surface retrieval operations such as a multiple cache recovery mission to Mars. The system employs autonomous navigation techniques, behavior-based control for surface retrieval operations, and an action selection mechanism based on a modified form of free flow hierarchy (Rosenblatt and Payton, 1989). This paper primarily describes the navigation and map-mapping subsystems of BISMARC. They are inspired by some recent studies of London taxi drivers indicating that the right hippo... | [] | Train |
203 | 4 | Contract-Net-Based Learning in a User-Adaptive Interface Agency . This paper describes a multi-agent learning approach to adaptation to users' preferences realized by an interface agency. Using a contract-net-based negotiation technique, agents as contractors as well as managers negotiate with each other to pursue the overall goal of dynamic user adaptation. By learning from indirect user feedback, the adjustment of internal credit vectors and the assignment of contractors that gained maximal credit with respect to the user's current preferences, the preceding session, and current situational circumstances can be realized. In this way, user adaptation is achieved without accumulating explicit user models but by the use of implicit, distributed user models. 1 Introduction Interface agents are computer programs that enhance the human-computer interaction by mediating a relationship between technical systems and users [Lau90]. On the one hand, they provide assistance to users by acting on his/her behalf and automating his/her actions [Nor94... | [
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204 | 3 | Creating Specialised Integrity Checks Through Partial Evaluation Of Meta-Interpreters Interpretation". Danny De Schreye is senior research associate of the Belgian National Fund for Scientific Research. We would like to thank Bern Martens for proof-reading several versions of this paper and for his helpful insights and comments on the topic of this paper. We would also like to thank him for his huge pile of references on integrity checking and for introducing the first author to the subject. We thank Bart Demoen for sharing his expertise on writing efficient Prolog programs. Our thanks also go to John Gallagher for pointing out several errors in an earlier version of the paper and for the fruitful discussions on partial evaluation and integrity checking. We are also grateful for discussions and extremely helpful comments by Hendrik Decker. Other interesting discussions about the topic of this paper were held with Stefan Decker, the members of the Compulog II project as well as with the participants of the 1996 Dagstuhl seminar on "Logic and the Meaning of Change". Fina... | [
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205 | 1 | On the Correspondence between Neural Folding Architectures and Tree Automata The folding architecture together with adequate supervised training algorithms is a special recurrent neural network model designed to solve inductive inference tasks on structured domains. Recently, the generic architecture has been proven as a universal approximator of mappings from rooted labeled ordered trees to real vector spaces. In this article we explore formal correspondences to the automata (language) theory in order to characterize the computational power (representational capabilities) of different instances of the generic folding architecture. As the main result we prove that simple instances of the folding architecture have the computational power of at least the class of deterministic bottom-up tree automata. It is shown how architectural constraints like the number of layers, the type of the activation functions (first-order vs. higher-order) and the transfer functions (threshold vs. sigmoid) influence the representational capabilities. All proofs are carried out in a c... | [
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206 | 3 | On Computational Representations of Herbrand Models . Finding computationally valuable representations of models of predicate logic formulas is an important issue in the field of automated theorem proving, e.g. for automated model building or semantic resolution. In this article we treat the problem of representing single models independently of building them and discuss the power of different mechanisms for this purpose. We start with investigating context-free languages for representing single Herbrand models. We show their computational feasibility and prove their expressive power to be exactly the finite models. We show an equivalence with "ground atoms and ground equations" concluding equal expressive power. Finally we indicate how various other well known techniques could be used for representing essentially infinite models (i.e. models of not finitely controllable formulas), thus motivating our interest in relating model properties with syntactical properties of corresponding Herbrand models and in investigating connections betwe... | [] | Test |
207 | 3 | Integrating Spatial Information And Image Analysis - One Plus One Makes Ten Photogrammetry and remote sensing have proven their efficiency for spatial data collection in many ways. Interactive mapping at digital workstations is performed by skilled operators, which guarantees excellent quality in particular of the geometric data. In this way, worldwide acquisition of a large number of national GIS databases has been supported and still a lot of production effort is devoted to this task. In the field of image analysis, it has become evident that algorithms for scene interpretation and 3D reconstruction of topographic objects, which rely on a single data source, cannot function efficiently. Research in two directions promises to be more successful. Multiple, largely complementary, sensor data like range data from laser scanners, SAR and panchromatic or multi-/hyper-spectral aerial images have been used to achieve robustness and better performance in image analysis. On the other hand, given GIS databases, e.g. layers from topographic maps, can be considered as vi... | [
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208 | 2 | QUEST - Querying specialized collections on the Web Ensuring access to specialized web-collections in a fast evolving web environment requires flexible techniques for orientation and querying. The adoption of meta search techniques for web-collections is hindered by the enormous heterogeneity of the resources. In this paper we introduce QUEST --- a system for querying specialized collections on the web. | [
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209 | 1 | Naive Bayes for Regression Abstract. Despite its simplicity, the naive Bayes learning scheme performs well on most classification tasks, and is often significantly more accurate than more sophisticated methods. Although the probability estimates that it produces can be inaccurate, it often assigns maximum probability to the correct class. This suggests that its good performance might be restricted to situations where the output is categorical. It is therefore interesting to see how it performs in domains where the predicted value is numeric, because in this case, predictions are more sensitive to inaccurate probability estimates. This paper shows how to apply the naive Bayes methodology to numeric prediction (i.e., regression) tasks by modeling the probability distribution of the target value with kernel density estimators, and compares it to linear regression, locally weighted linear regression, and a method that produces “model trees”—decision trees with linear regression functions at the leaves. Although we exhibit an artificial dataset for which naive Bayes is the method of choice, on real-world datasets it is almost uniformly worse than locally weighted linear regression and model trees. The comparison with linear regression depends on the error measure: for one measure naive Bayes performs similarly, while for another it is worse. We also show that standard naive Bayes applied to regression problems by discretizing the target value performs similarly badly. We then present empirical evidence that isolates naive Bayes ’ independence assumption as the culprit for its poor performance in the regression setting. These results indicate that the simplistic statistical assumption that naive Bayes makes is indeed more restrictive for regression than for classification. | [
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210 | 5 | Paradigma: Agent Implementation through Jini One of the key problems of recent years has been the divide between theoretical work in agent-based systems and its practical complement which have, to a large extent, developed along different paths. The Paradigma implementation framework has been designed with the aim of narrowing this gap. It relies on an extensive formal agent framework implemented using recent advances in Java technology. Specifically, Paradigma uses Jini connectivity technology to enable the creation of on-line communities in support of the development of agent-based systems. 1 Introduction In a networked environment that is highly interconnected, interdependent and heterogeneous, we are faced with an explosion of information and available services that are increasingly hard to manage. Agent-based systems can provide solutions to these problems as a consequence of their dynamics of social interaction; communication and cooperation can be used to effectively model problem domains through the interaction of agent... | [
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211 | 3 | Rewriting Conjunctive Queries Using Views in Description Logics with Existential Restrictions this paper, extending the work of [8], we study the problem of rewriting conjunctive queries over DL expressions into conjunctive queries using a set of views that are a set of distinguished DL expressions, for three DLs allowing existential restrictions: FLE , ALE and ALNE . Thus, our rewriting problem is: given a conjunctive query over expressions from a DL L 2 fFLE;ALE ; ALNEg and a set of views V over expressions from L, we want to compute a representative set of all the rewritings of the query that are conjunctive queries over V. By representative set we mean that this set contains at least the rewritings that are maximally contained in the query. | [
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212 | 1 | Applying Parallelism to Improve Genetic Algorithm-based Design Optimization Introduction The abundance of powerful workstations makes course-grained parallelization an obvious enhancement to many optimization techniques, including genetic algorithms [Gol89, DM97]. While initial modifications have been made to GADO (Genetic Algorithm for Design Optimization [Ras98, RHG97]), such changes have not been carefully analyzed for potential impacts on quality. More generally, parallelization has the potential to improve GA performance through the use of alternative models of computation. Parallelism can certainly reduce the total elapsed clock-time for a solution, but as a change in model of computation (either real or simulated) , it can change the number of simulator calls and even make new solutions achievable. The effects of parallelization on GADO were investigated during my summer internship at the Center for Computational Design. 2 Objectives Since a straightforward parallelized implementation already existed, my first tasks were to ana | [] | Validation |
213 | 1 | Using the CONDENSATION Algorithm for Robust, Vision-based Mobile Robot Localization To navigate reliably in indoor environments, a mobile robot must know where it is. This includes both the ability of globally localizing the robot from scratch, as well as tracking the robot's position once its location is known. Vision has long been advertised as providing a solution to these problems, but we still lack efficient solutions in unmodified environments. Many existing approaches require modification of the environment to function properly, and those that work within unmodified environments seldomly address the problem of global localization. In this paper we present a novel, vision-based localization method based on the CONDENSATION algorithm [17, 18], a Bayesian filtering method that uses a samplingbased density representation. We show how the CONDEN- SATION algorithm can be used in a novel way to track the position of the camera platform rather than tracking an object in the scene. In addition, it can also be used to globally localize the camera platform, given a visua... | [
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214 | 0 | An Intelligent Agent Framework In VRML Worlds actions, e.g. move to next room, are received by it and consequently send to the EAC. Finally, the abstract action arrives at the Virtual Reality Management Unit that specifies in detail the received actions. It provides specific values concerning the orientation and position of the avatar, e.g. it specifies the coordinates, orientation and path so that it can successfully move to the next room, and sends them as commands to the Virtual Reality World Browser. The browser executes the command by altering the virtual environment appropriately. When changes have been performed the AEC unit notifies the logical core that the action has been successfully executed and the logical core goes on by updating its internal and external state. Consequently, the agent looks around into the virtual space, gathers any additional information and decides the next step it should take to satisfy its goals. | [
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215 | 1 | Model-Free Least-Squares Policy Iteration We propose a new approach to reinforcement learning which combines least squares function approximation with policy iteration. Our method is model-free and completely off policy. We are motivated by the least squares temporal difference learning algorithm (LSTD), which is known for its efficient use of sample experiences compared to pure temporal difference algorithms. LSTD is ideal for prediction problems, however it heretofore has not had a straightforward application to control problems. Moreover, approximations learned by LSTD are strongly influenced by the visitation distribution over states. Our new algorithm, Least-Squares Policy Iteration (LSPI) addresses these issues. The result is an off-policy method which can use (or reuse) data collected from any source. We test LSPI on several problems, including a bicycle simulator in which it learns to guide the bicycle to a goal efficiently by merely observing a relatively small number of completely random trials. | [
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216 | 3 | The BASIS System: a Benchmarking Approach for Spatial Index Structures This paper describes the design of the BASIS prototype system, which is currently under implementation. BASIS stands for Benchmarking Approach for Spatial Index Structures. It is a prototype system aiming at performance evaluation of spatial access methods and query processing strategies, under different data sets, various query types, and different workloads. BASIS is based on a modular architecture, composed of a simple storage manager, a query processor, and a set of algorithmic techniques to facilitate benchmarking. The main objective of BASIS is twofold: (i) to provide a benchmarking environment for spatial access methods and related query evaluation techniques, and (ii) to allow comparative studies of spatial access methods in different cases but under a common framework. We currently extend it to support the fundamental features of spatiotemporal data management and access methods. | [
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217 | 4 | Exploration of Perceptual Computing for Smart-Its The future success of ubiquitous computing depends to a big part on how well applications can adapt to their environment and act accordingly. This thesis has set itself the goal of exploring perceptual computing for Smart-Its, which is one such ubiquitous computing vision. | [
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218 | 3 | ToX - The Toronto XML Engine Abstract. We present ToX – the Toronto XML Engine – a repository for XML data and metadata, which supports real and virtual XML documents. Real documents are stored as files or mapped into relational or object databases, depending on their structuredness; indices are defined according to the storage method used. Virtual documents can be remote documents, defined as arbitrary WebOQL queries, or views, defined as queries over documents registered in the system. The system catalog contains metadata for the documents, especially their schemata, used for query processing and optimization. Queries can range over both the catalog and the documents, and multiple query languages are supported. In this paper we describe the architecture and main of ToX; we present our indexing and storage strategies, including two novel techniques; and we discuss our query processing strategy. The project started recently and is under active development. 1 | [
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219 | 5 | Logic-Based Subsumption Architecture In this paper we describe a logic-based AI architecture based on Brooks' Subsumption Architecture. We axiomatize each of the layers of control in his system separately and use independent theorem provers to derive each layer's output actions given its inputs. We implement the subsumption of lower layers by higher layers using circumscription. We give formal semantics to our approach. 1 Introduction In [?], Brooks proposed a reactive architecture embodying an approach to robot control different on various counts from traditional approaches. He decomposed the problem into layers corresponding to levels of behavior, rather than according to a sequential, functional form. Within this setting he introduced the idea of subsumption, that is, that more complex layers could not only depend on lower, more reactive layers, but could also influence their behavior. The resulting architecture was one that could service simultaneously multiple, potentially conflicting goals in a reactive fashi... | [
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220 | 2 | REFEREE: An open framework for practical testing of recommender systems using ResearchIndex Automated recommendation (e.g., personalized product recommendation on an ecommerce web site) is an increasingly valuable service associated with many databases--typically online retail catalogs and web logs. Currently, a major obstacle for evaluating recommendation algorithms is the lack of any standard, public, real-world testbed appropriate for the task. In an attempt to fill this gap, we have created REFEREE, a framework for building recommender systems using ResearchIndex--a huge online digital library of computer science research papers--so that anyone in the research community can develop, deploy, and evaluate recommender systems relatively easily and quickly. Research Index is in many ways ideal for evaluating recommender systems, especially so-called hybrid recommenders that combine information filtering and collaborative filtering techniques. The documents in the database are associated with a wealth of content information (author, title, abstract, full text) and collaborative information (user behaviors), as well as linkage information via the citation structure. Our framework supports more realistic evaluation metrics that assess user buy-in directly, rather than resorting to offline metrics like prediction accuracy that may have little to do with end user utility. The sheer scale of ResearchIndex (over 500,000 documents with thousands of user accesses per hour) will force algorithm designers to make real-world trade-offs that consider performance, not just accuracy. We present our own tradeoff decisions in building an example hybrid recommender called PD-Live. The algorithm uses content-based similarity information to select a set of documents from which to recommend, and collaborative information to rank the documents. PD-Live performs reasonably well compared to other recommenders in ResearchIndex. | [
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221 | 0 | Performance Analysis of Mobile Agents for Filtering Data Streams on Wireless Networks Wireless networks are an ideal environment for mobile agents, since their mobility allows them to move across an unreliable link to reside on a wired host, next to or closer to the resources that they need to use. Furthermore, clientspecific data transformations can be moved across the wireless link and run on a wired gateway server, reducing bandwidth demands. In this paper we examine the tradeoffs faced when deciding whether to use mobile agents in a datafiltering application where numerous wireless clients filter information from a large data stream arriving across the wired network. We develop an analytical model and use parameters from filtering experiments conducted during a U.S. Navy Fleet Battle Experiment (FBE) to explore the model's implications. 1. Introduction Mobile agents are programs that can migrate from host to host in a network of computers, at times and to places of their own choosing. Unlike applets, both the code and the execution state (heap and stack) move with... | [
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222 | 3 | Latent Semantic Indexing: A Probabilistic Analysis Latent semantic indexing (LSI) is an information retrieval technique based on the spectral analysis of the term-document matrix, whose empirical success had heretofore been without rigorous prediction and explanation. We prove that, under certain conditions, LSI does succeed in capturing the underlying semantics of the corpus and achieves improved retrieval performance. We also propose the technique of random projection as a way of speeding up LSI. We complement our theorems with encouraging experimental results. We also argue that our results may be viewed in a more general framework, as a theoretical basis for the use of spectral methods in a wider class of applications such as collaborative filtering. Computer Science Division, U. C. Berkeley, Berkeley, CA 94720. Email: christos@cs.berkeley.edu. y IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120. Email: pragh@almaden.ibm.com. z Computer Science Department, Meiji University, Tokyo, Japan. Email: htamaki@cs.meiji.... | [
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223 | 0 | The Eel Programming Language and Internal Concurrency in Logic Agents This paper describes work done on creating the logic programming language Eel. The language is designed for implementing agents with a behaviour based, concurrent internal architecture. The paper also suggests a new such architecture which improves on the ones currently available. It gives examples of how parts of that architecture are implemented in Eel and comments that the Agent Oriented Programming paradigm currently contains two different metaphors for concurrency. Eel's event based approach to process communication and process initiation introduces an explicit representation of state to a logic program. A new declarative approach to object states is demonstrated as a part of the object oriented implementation of the suggested agent architecture. As well as being a programming language, Eel is a formalism which is well suited for logic based machine learning of behaviour and interaction. This paper briefly outlines the scope for using such learning to improve on exist... | [
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224 | 2 | Image Retrieval: Current Techniques, Promising Directions And Open Issues This paper provides a comprehensive survey of the technical achievements in the research area of image retrieval, especially content-based image retrieval, an area that has been so active and prosperous in the past few years. The survey includes 100+ papers covering the research aspects of image feature representation and extraction, multidimensional indexing, and system design, three of the fundamental bases of content-based image retrieval. Furthermore, based on the state-of-the-art technology available now and the demand from real-world applications, open research issues are identified and future promising research directions are suggested. C ○ 1999 Academic Press 1. | [
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225 | 1 | Multi-Layer Incremental Induction . This paper describes a multi-layer incremental induction algorithm, MLII, which is linked to an existing nonincremental induction algorithm to learn incrementally from noisy data. MLII makes use of three operations: data partitioning, generalization and reduction. Generalization can either learn a set of rules from a (sub)set of examples, or refine a previous set of rules. The latter is achieved through a redescription operation called reduction: from a set of examples and a set of rules, we derive a new set of examples describing the behaviour of the rule set. New rules are extracted from these behavioral examples, and these rules can be seen as meta-rules, as they control previous rules in order to improve their predictive accuracy. Experimental results show that MLII achieves significant improvement on the existing nonincremental algorithm HCV used for experiments in this paper, in terms of rule accuracy. 1 Introduction Existing machine learning algorithms can be generally distin... | [
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226 | 5 | Super Logic Programs Recently, considerable interest and research e#ort has been given to the problem of finding a suitable extension of the logic programming paradigm beyond the class of normal logic programs. In order to demonstrate that a class of programs can be justifiably called an extension of logic programs one should be able to argue that: . the proposed syntax of such programs resembles the syntax of logic programs but it applies to a significantly broader class of programs; . the proposed semantics of such programs constitutes an intuitively natural extension of the semantics of normal logic programs; . there exists a reasonably simple procedural mechanism allowing, at least in principle, to compute the semantics; . the proposed class of programs and their semantics is a special case of a more general non-monotonic formalism which clearly links it to other well-established non-monotonic formalisms. In this paper we propose a specific class of extended logic programs which will be (modestly) called super logic programs or just super-programs. We will argue that the class of super-programs satisfies all of the above conditions, and, in addition, is su#ciently flexible to allow various application-dependent extensions and modifications. We also provide a brief description of a Prolog implementation of a query-answering interpreter for the class of super-programs which is available via FTP and WWW. Keywords: Non-Monotonic Reasoning, Logics of Knowledge and Beliefs, Semantics of Logic Programs and Deductive Databases. # An extended abstract of this paper appeared in the Proceedings of the Fifth International Conference on Principles of Knowledge Representation and Reasoning (KR'96), Boston, Massachusetts, 1996, pp. 529--541. + Partially supported by the National Science Fou... | [
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227 | 1 | Supporting Flexibility. A Case-Based Reasoning Approach This paper presents a case-based reasoning system TA3. We address the flexibility of the case-based reasoning process, namely flexible retrieval of relevant experiences, by using a novel similarity assessment theory. To exemplify the advantages of such an approach, we have experimentally evaluated the system and compared its performance to the performance of non-flexible version of TA3 and to other machine learning algorithms on several domains. Introduction Flexible Computation There are many situation when resources are scarce and when the system has to make decision as to how to proceed with further computation in order to make the right tradeoff between quality of the answer and resources needed. In several domains, such as medicine, robotics, financing, etc., if the answer to a query is not produced within a certain time limit it may become useless. Such family of problems has been a motivation for designing anytime algorithms (Dean & Boddy 1988; Frisch & Haddawy 1994), algorit... | [
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228 | 3 | Indexing Moving Points We propose three indexing schemes for storing a set S of N points in the plane, each moving along a linear trajectory, so that a query of the following form can be answered quickly: Given a rectangle R and a real value t q , report all K points of S that lie inside R at time t q . We first present an indexing structure that, for any given constant " ? 0, uses O(N=B) disk blocks, where B is the block size, and answers a query in O((N=B) 1=2+" + K=B) I/Os. It can also report all the points of S that lie inside R during a given time interval. A point can be inserted or deleted, or the trajectory of a point can be changed, in O(log 2 B N) I/Os. Next, we present a general approach that improves the query time if the queries arrive in chronological order, by allowing the index to evolve over time. We obtain a tradeoff between the query time and the number of times the index needs to be updated as the points move. We also describe an indexing scheme in which the number of I/Os required to answer a query depends monotonically on the difference between t q and the current time. Finally, we develop an efficient indexing scheme to answer approximate nearest-neighbor queries among moving points. An extended abstract of this paper appeared in the Proceedings of the 19th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems. y Center for Geometric Computing, Department of Computer Science, Duke University, Box 90129, Durham, NC 27708--0129; pankaj@cs.duke.edu; http://www.cs.duke.edu/ pankaj. Supported in part by National Science Foundation grants EIA--9870734, EIA--9972879, and CCR--9732787, by Army Research Of fice MURI grant DAAH04-- 96--1--0013, by a Sloan fellowship, and by a grant from the U.S.-Israeli Binational Science Foundation. z Center ... | [
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229 | 0 | Multi-Layer Methods and the Optimal Optimizer Multi-Layer Methods are methods that act on several layers simultaneously. Examples of multi-layer methods are found in multi-agent systems (global and per-agent behavior), in learning (e.g. boosting, bias tuning), in self-adaptive methods (such as evolution strategies), in hybrid approaches, and in optimization (e.g. multiple runs, result pooling). We give a formal definition of what a multi-layer method is. We discuss the relationship with the no free lunch theorem, to show that such a thing as the optimal optimizer exists, and how multi-layer methods can be used to approximate it. | [
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230 | 3 | Scalable Trigger Processing + Current database trigger systems have extremely limited scalability. This paper proposes a way to develop a truly scalable trigger system. Scalability to large numbers of triggers is achieved with a trigger cache to use main memory effectively, and a memory-conserving selection predicate index based on the use of unique expression formats called expression signatures. A key observation is that if a very large number of triggers are created, many will have the same structure, except for the appearance of different constant values. When a trigger is created, tuples are added to special relations created for expression signatures to hold the trigger's constants. These tables can be augmented with a database index or main-memory index structure to serve as a predicate index. The design presented also uses a number of types of concurrency to achieve scalability, including token (tuple)-level, condition-level, rule action-level, and datalevel concurrency. 1. Introduction Trigger feature... | [
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231 | 0 | Agent-Based Modeling for Holonic Manufacturing Systems with Fuzzy Control Agent-based systems technologies are of emerging interest in the specification and implementation of complex systems. This article introduces the CASA agent development system which seamlessly combines the BDI (Belief Desire Intention) approach with the FIPA agent communication language standard and an integrated specification of fuzzy controllers. The behavior of agents is defined by strategies which basically correspond to extended guarded horn clauses with priorities. The presented concepts are introduced by an example from Computer Integrated Manufacturing (CIM). The example gives the specification of a fuzzy controller for a manufacturing station in the context of a holonic manufacturing system (HMS). 1 Introduction Agent-based systems technologies in the sense of distributed computing is an area of emerging interest in the domain of complex systems design. The agent-based paradigm can be seen as a real enhancement of the objectoriented paradigm where objects become autonomous, ... | [
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232 | 1 | Robust Entropy Estimation Strategies Based on Edge Weighted Random Graphs (with corrections) In this paper we treat the problem of robust entropy estimation given a multidimensional random sample from an unknown distribution. In particular, we consider estimation of the Renyi entropy of fractional order which is insensitive to outliers, e.g. high variance contaminating distributions, using the k-point minimal spanning tree (kMST) . A greedy algorithm for approximating the NP-hard problem of computing the k-minimal spanning tree is given which is a generalization of the potential function partitioning method of Ravi etal. 1 The basis for our approach is an asymptotic theorem establishing that the log of the overall length or weight of the greedy approximation is a strongly consistent estimator of the Renyi entropy. Quantitative robustness of the estimator to outliers is established using Hampel's method of inuence functions. 2 The structure of the inuence function indicates that the k-MST is a natural extension of the one dimensional -trimmed mean for multi-dimensional... | [
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233 | 3 | Using Java and CORBA for Implementing Internet Databases We describe an architecture called WebFINDIT that allows dynamic couplings of Web accessible databases based on their content and interest. We propose an implementation using WWW, Java, JDBC, and CORBA's ORBs that communicate via the CORBA's IIOP protocol. The combination of these technologies offers a compelling middleware infrastructure to implement wide-area enterprise applications. In addition to a discussion of WebFINDIT's core concepts and implementation architecture, we also discuss an experience of using WebFINDIT in a healthcare application. 1 Introduction The growth of the Internet and the Web increased dramatically the need for data sharing. The Web has brought a wave of new users and service providers to the Internet. It contains a huge quantity of heterogeneous information and services (e.g., home pages, online digital libraries, product catalogs, and so on) (Bouguettaya et al. 1998). The result is that the Web is now accepted as the de facto support in all domains of li... | [
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234 | 0 | Cross Entropy Guided Ant-like Agents Finding Dependable Primary/Backup Path Patterns in Networks Telecommunication network owners and operators have for half a century been well aware of the potential loss of revenue if a major trunk is damaged, thus dependability at high cost has been implemented. A simple, effective and common dependability scheme is 1:1 protection with 100% capacity redundancy in the network. A growing number of applications in need of dependable connections with specific requirements to bandwidth and delay have started using the internet (which only provides best effort transport) as their base communication service. In this paper we adopt the 1:1 protection scheme and incorporate it as part of a routing system applicable for internet infrastructures. 100% capacity redundancy is no longer required. A distributed stochastic path finding (routing) algorithm based on Rubinstein's Cross Entropy method for combinatorial optimisation is presented. Early results from Monte Carlo simulations indeed indicate that the algorithm is capable of finding pairs of independent primary and backup paths satisfying specific bandwidth a constraints. | [
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235 | 0 | Policy Controlled Mobility The mobility of software components seems an interesting solution for the deployment of web services and applications in the Internet global infrastructure and also in mobile ad-hoc networks. The network infrastructure already supports several forms of code mobility to make possible to dynamically reconfigure bindings between code fragments and locations where they are to be executed. However, more work is still to be done to facilitate the specification and the enforcement of the mobility behaviour of software components. The traditional approach to embed the migration strategy into the component at design time can not suit the dynamicity of the new network scenarios. Mobile components should instead be enhanced with the possibility to adapt their mobility behaviour to evolving application and environment conditions and to react to unforeseen events. To reach this goal, the paper proposes the adoption of policy based systems to abstract away the specification of migration strategies from the component code. This approach permits to change the mobility behaviour of components without intervention on the component code. We have experienced the dynamicity and flexibility of the proposed approach in the framework obtained by integrating a policy-based management system in a mobile agent environment. Keywords: Mobility, Migration Policies, Adaptation Mobile Agents, Reconfiguration. 1 | [
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236 | 2 | User Behavior Analysis of Location Aware Search Engine Rapid growth of internet access from mobile users puts much importance on location specific information on the web. An unique web service called Mobile Info Search (MIS) from NTT Laboratories gathers the information and provide location aware search facilities. We performed association rule mining and sequence pattern mining against the access log which was accumulated at the MIS site in order to get some insight into the behavior of mobile users regarding the spatial information on the web. Detail web log mining process and the rules we derived are reported in this paper. | [
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237 | 1 | Bayesian Representations and Learning Mechanisms for Content-Based Image Retrieval We have previously introduced a Bayesian framework for content-based image retrieval (CBIR) that relies on a generative model for feature representation based on embedded mixtures. This is a truly generic image representation that can jointly model color and texture and has been shown to perform well across a broad spectrum of image databases. In this paper, we expand the Bayesian framework along two directions. First, we show that the formulation of CBIR as a problem of Bayesian inference leads to a natural criteria for evaluating local image similarity without requiring any image segmentation. This allows the practical implementation of retrieval systems where users can provide image regions, or objects, as queries. Region-based queries are significantly less ambiguous than queries based on entire images leading to significant improvements in retrieval precision. Second, we present a Bayesian learning algorithm that relies on belief propagation to integrate feedback provided by the... | [
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238 | 3 | An Ounce of Prevention is Worth A Pound of Cure: Formal Verification for Consistent Database Evolution Consistency of a database is as an important property that must be preserved at all times. In most OODB systems today, application code can directly access and alter both the data as well as the structure of the database. As a consequence application code can potentially violate the integrity of the database, in terms of the invariants of the data model, the user-specified application constraints, and even the referential integrity of the objects themselves. A common form of consistency management in most databases today is to encode constraints at the system level (e.g., foreign keys), or at the trigger based level (e.g., user constraints) and to perform transaction rollback on discovery of any violation of these constraints. However, for programs that alter the structure as well as the objects in a database, such as an extensible schema evolution program, roll-backs are expensive and add to the already astronomical cost of doing schema evolution. In this paper, pre-execution ... | [] | Train |
239 | 0 | Specification of Heterogeneous Agent Architectures . Agent-based software applications need to incorporate agents having heterogeneous architectures in order for each agent to optimally perform its task. HEMASL is a simple meta-language used to specify intelligent agents and multi-agent systems when different and heterogeneous agent architectures must be used. HEMASL specifications are based on an agent model that abstracts several existing agent architectures. The paper describes some of the features of the language, presents examples of its use and outlines its operational semantics. We argue that adding HEMASL to CaseLP, a specification and prototyping environment for MAS, can enhance its flexibility and usability. 1 Introduction Intelligent agents and multi-agent systems (MAS) are increasingly being acknowledged as the "new" modelling techniques to be used to engineer complex and distributed software applications [17, 9]. Agent-based software development is concerned with the realization of software applications modelled ... | [
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240 | 0 | Multiagent Learning Using a Variable Learning Rate Learning to act in a multiagent environment is a difficult problem since the normal definition of an optimal policy no longer applies. The optimal policy at any moment depends on the policies of the other agents. This creates a situation of learning a moving target. Previous learning algorithms have one of two shortcomings depending on their approach. They either converge to a policy that may not be optimal against the specific opponents ’ policies, or they may not converge at all. In this article we examine this learning problem in the framework of stochastic games. We look at a number of previous learning algorithms showing how they fail at one of the above criteria. We then contribute a new reinforcement learning technique using a variable learning rate to overcome these shortcomings. Specifically, we introduce the WoLF principle, “Win or Learn Fast, ” for varying the learning rate. We examine this technique theoretically, proving convergence in self-play on a restricted class of iterated matrix games. We also present empirical results on a variety of more general stochastic games, in situations of self-play and otherwise, demonstrating the wide applicability of this method. Key words: Multiagent learning, reinforcement learning, game theory 1 | [
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241 | 4 | Smart Playing Cards A Ubiquitous Computing Game Abstract. Recent technological advances allow for turning parts of our everyday environment into so–called smart environments. In this paper we present the “Smart Playing Cards ” application, a ubiquitous computing game that augments a classical card game with information–technological functionality, in contrast to developing new games around the abilities of available technology. Furthermore, we present the requirements such an application makes on a supporting software infrastructure for ubiquitous computing. | [
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242 | 3 | Query Optimization for Semistructured Data using Path Constraints in a Deterministic Data Model . Path constraints have been studied for semistructured data modeled as a rooted edge-labeled directed graph [4, 11--13]. In this model, the implication problems associated with many natural path constraints are undecidable [11, 13]. A variant of the graph model, called the deterministic data model , was recently proposed in [10]. In this model, data is represented as a graph with deterministic edge relations, i.e., the edges emanating from any node in the graph have distinct labels. This model is more appropriate for representing, e.g., ACeDB [27] databases and Web sites. This paper investigates path constraints for the deterministic data model. It demonstrates the application of path constraints to, among others, query optimization. Three classes of path constraints are considered: the language Pc introduced in [11], an extension of Pc , denoted by P w c , by including wildcards in path expressions, and a generalization of P w c , denoted by P c , by representing pa... | [
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243 | 1 | Comparing Evolutionary Programs and Evolutionary Pattern Search Algorithms: A Drug Docking Application Evolutionary programs (EPs) and evolutionary pattern search algorithms (EPSAs) are two general classes of evolutionary methods for optimizing on continuous domains. The relative performance of these methods has been evaluated on standard global optimization test functions, and these results suggest that EPSAs more robustly converge to nearoptimal solutions than EPs. In this paper we evaluate the relative performance of EPSAs and EPs on a real-world application: flexible ligand binding in the Autodock docking software. We compare the performance of these methods on a suite of docking test problems. Our results confirm that EPSAs and EPs have comparable performance, and they suggest that EPSAs may be more robust on larger, more complex problems. 1 Introduction Evolutionary programs (EPs) and evolutionary pattern search algorithms (EPSAs) are two classes of evolutionary algorithms (EAs) that have been specifically developed for solving problems of the form min x2R n f(x): In particula... | [
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244 | 1 | Making Use of Population Information in Evolutionary Artificial Neural Networks This paper is concerned with the simultaneous evolution of artificial neural network (ANN) architectures and weights. The current practice in evolving ANN's is to choose the best ANN in the last generation as the final result. This paper proposes a different approach to form the final result by combining all the individuals in the last generation in order to make best use of all the information contained in the whole population. This approach regards a population of ANN's as an ensemble and uses a combination method to integrate them. Although there has been some work on integrating ANN modules [2], [3], little has been done in evolutionary learning to make best use of its population information. Four linear combination methods have been investigated in this paper to illustrate our ideas. Three real-world data sets have been used in our experimental studies, which show that the recursive least-square (RLS) algorithm always produces an integrated system that outperforms the best individual. The results confirm that a population contains more information than a single individual. Evolutionary learning should exploit such information to improve generalization of learned systems. | [
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245 | 0 | Organisational Rules as an Abstraction for the Analysis and Design of Multi-Agent Systems Multi-agent systems... In this paper we introduce three additional organisational concepts - organisational rules, organisational structures, and organisational patterns - and discuss why we believe they are necessary for the complete specification of computational organisations. In particular, we focus on the concept of organisational rules and introduce a formalism, based on temporal logic, to specify them. This formalism is then used to drive the definition of the organisational structure and the identification of the organisational patterns. Finally, the paper sketches some guidelines for a methodology for agent-oriented systems based on our expanded set of organisational abstractions. | [
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246 | 4 | An Agent-Based Approach to the Construction of Floristic Digital Libraries This paper describes an agent-assisted approach to the construction of floristic digital libraries, which consist of very large botanical data repositories and related services. We propose an environment, termed Chrysalis, in which authors of plant morphologic descriptions can enter data into a digital library via a web-based editor. An agent that runs concurrently with the editor suggests potentially useful morphologic descriptions based on similar documents existing in the library. Benefits derived from the introduction of Chrysalis include reduced potential for errors and data inconsistencies, increased parallelism among descriptions, and considerable savings in the time regularly spent in visually checking for parallelism and manually editing data. KEYWORDS: agents, agent-based interfaces, floristic digital libraries, FNA, Chrysalis. INTRODUCTION Constructing the vast data repositories that will support knowledge-intensive activities in digital libraries poses problems of enormo... | [
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247 | 3 | Effective Temporal Aggregation using Point-based Trees . Temporal databases introduce the concept of time into underlying data, and provide built-in facilities that allow users to store and retrieve time-varying data. The aggregation in temporal databases, that is, temporal aggregation is an extension of conventional aggregation on the domain and range of aggregates to include time concept. Temporal aggregation is important for various applications, but is very expensive. In this paper, we propose a new tree structure for temporal aggregation, called PA-tree, and aggregate processing method based on the PA-tree. We show that the time complexity of the proposed method is better than those of the existing methods. The time complexity of the proposed method is shown to be indeed the lower bound of the problem. We perform comparative experiments and show the performance advantage of our proposed method in practice. 1 Introduction While conventional database systems store the most recent snapshots of the real world, temporal datab... | [
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248 | 4 | Business Suitability Principles for Workflow Modelling By incorporating aspects of coordination and collaboration, workflow implementations of information systems require a sound conceptualisation of business processing semantics. Traditionally, the success of conceptual modelling techniques has depended largely on the adequacy of conceptualisation, expressive power, comprehensibility and formal foundation. An equally important requirement, particularly with the increased conceptualisation of business aspects, is business suitability. In this paper, the focus is on the business suitability of workflow modelling for a commonly encountered class of (operational) business processing, e.g. those of insurance claims, bank loans and land conveyancing. A general assessment is first conducted on some integrated techniques characterising well-known paradigms - structured process modelling, object-oriented modelling, behavioural process modelling and business-oriented modelling. Through this, an insight into business suitability within the broader... | [
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249 | 4 | A Scalable and Ontology-Based P2P Infrastructure for Semantic Web Services Semantic Web Services are a promising combination of Semantic Web and Web service technology, aiming at providing means of automatically executing, discovering and composing semantically marked-up Web services. We envision peer-to-peer networks which allow for carrying out searches in real-time on permanently reconfiguring networks to be an ideal injastructure for deploying a network of Semantic Web Service providers. However, P2P networks evolving in an unorganized manner suffer jom serious scalability problems, limiting the number of nodes in the network, creating network overload and pushing search times to unacceptable limits. We address these problems by imposing a deterministic shape on P2P networks: We propose a graph topology which allows for very efficient broadcast and search, and we provide an efficient topology construction and maintenance algorithm which, crucial to symmetric peer-to-peer networks, does neither require a central server nor super nodes in the network. We show how our scheme can be made even more efficient by using a globally known ontology to determine the organization of peers in the graph topology, allowing for efficient concept-based search. | [
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250 | 5 | Boticelli: A Single-Camera Mobile Robot Using New Approaches to Range Data Fusion, World Modeling, and Navigation Planning ID: A083 Abstract Boticelli is a mobile robot, designed and built for testing new approaches in stereo vision, world modeling, data fusion, map extraction, reinforcement learning and navigation planning. A single camera is used to capture depth information by taking advantage of camera movements. The main thrust of the new approaches is to replace well-known techniques, that depend upon grids of points in space with techniques that use continuous, piecewise linear functions. These techniques scale well to large, complex environments. Keywords: mobile agents, mapping and exploration, reinforcement learning Acknowledgements This research was supported mainly by the Defence Research Establishment Suffield (contract W7702-6R594 /001 to Dendronic Decisions Limited). We are very grateful to the Scientific Authority Dr. Simon Barton for his guidance. Travel was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC). Help of Kyle Palmer in designing the multi... | [
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251 | 0 | Response Generation in Collaborative Negotiation In collaborative planning activities, since the agents are autonomous and heterogeneous, it is inevitable that conflicts arise in their beliefs during the planning process. In cases where such conflicts are relevant to the task at hand, the agents should engage in collaborative negotiation as an attempt to square away the discrepancies in their beliefs. This paper presents a computational strategy for detecting conflicts regarding proposed beliefs and for engaging in collaborative negotiation to resolve the conflicts that warrant resolution. Our model is capable of selecting the most effective aspect to address in its pursuit of conflict resolution in cases where multiple conflicts arise, and of selecting appropriate evidence to justify the need for such modification. Furthermore, by capturing the negotiation process in a recursive Propose-Evaluate-Modify cycle of actions, our model can successfully handle embedded negotiation subdialogues. 1 Introduction In collaborative consultat... | [
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252 | 3 | View Security as the Basis for Data Warehouse Security Access . permissions in a data warehouse are currently managed in a separate world from the sources' policies. The consequences are inconsistencies, slow response to change, and wasted administrative work. We present a different approach, which treats the sources' exported tables and the warehouse as part of the same distributed database. Our main result is a way to control derived products by extending SQL grants rather than creating entirely new mechanisms. We provide a powerful, sound inference theory that derives permissions on warehouse tables (both materialized and virtual), making the system easier to administer and its applications more robust. We also propose a new permission construct suitable for views that filter data from mutually-suspicious parties. 1 Introduction A key challenge for data warehouse security is how to manage the entire system coherently -- from sources and their export tables, to warehouse stored tables (conventional and cubes) and vi... | [
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253 | 3 | Achieving Consistency in Mobile Databases through Localization in PRO-MOTION There is great need and potential for traditional transaction support in a mobile computing environment. However, owing to the inherent limitations of mobile computing, we need to augment the well-developed techniques of Database Management Systems with new approaches. In this paper, we focus on the challenge of assuring data consistency. Our approach of localization is to reformulate global constraints so as to enhance the autonomy of the mobile hosts. We show how this approach unifies techniques of maintaining replicated data with methods of enforcing polynomial inequalities. We also discuss how localization can be implemented in PRO-MOTION, a flexible infrastructure for transaction processing in a mobile environment. 1. Introduction Thanks to the relentless advances in semiconductors, the number of users with mobile computers (we will refer to these machines as mobile hosts or MHs) continues to increase. These users have discovered that exciting developments in wireless technology... | [
1047
] | Validation |
254 | 3 | Optimizatizing the Performance of Schema Evolution Sequences More than ever before schema transformation is a prevalent problem that needs to be addressed to accomplish for example the migration of legacy systems to the newer OODB systems, the generation of structured web pages from data in database systems, or the integration of systems with different native data models. Such schema transformations are typically composed of a sequence of schema evolution operations. The execution of such sequences can be very timeintensive, possibly requiring many hours or even days and thus effectively making the database unavailable for unacceptable time spans. While researchers have looked at the deferred execution approach for schema evolution in an effort to improve availability of the system, to the best of our knowledge ours is the first effort to provide a direct optimization strategy for a sequence of changes. In this paper, we propose heuristics for the iterative elimination and cancellation of schema evolution primitives as well as for the merging of... | [
3183
] | Test |
255 | 2 | Web Mining Research: A Survey With the huge amount of information available online, the World Wide Web is a fertile area for data mining research. The Web mining research is at the cross road of research from several research communities, such as database, information retrieval, and within AI, especially the sub-areas of machine learning and natural language processing. However, there is a lot of confusions when comparing research efforts from different point of views. In this paper, we survey the research in the area of Web mining, point out some confusions regarded the usage of the term Web mining and suggest three Web mining categories. Then we situate some of the research with respect to these three categories. We also explore the connection between the Web mining categories and the related agent paradigm. For the survey, we focus on representation issues, on the process, on the learning algorithm, and on the application of the recent works as the criteria. We conclude the paper with some research issues. | [
39,
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721,
836,
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1838,
2068,
2283,
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2503,
2760,
2929,
3138
] | Train |
256 | 2 | Digital Library Resources as a Basis for Collaborative Work The creation of large, networked, digital document resources has greatly facilitated information access and dissemination. We suggest that such resources can further enhance how we work with information, namely, that they can provide a substrate that supports collaborative work. We focus on one form of collaboration, annotation, by which we mean any of an open-ended number of creative document manipulations which are useful to record and to share with others. Widespread digital document dissemination required technological enablers, such as web clients and servers. The resulting infrastructure is one in which information may be widely shared by individuals across administrative boundaries. To achieve the same ubiquitous availability for annotation requires providing support for spontaneous collaboration, that is, for collaboration across administrative boundaries without significant prior agreements. Annotation is not more commonplace, we suggest, because the technological needs of sp... | [
2909
] | Validation |
257 | 4 | MSVT: A Virtual Reality-Based Multimodal Scientific Visualization Tool Recent approaches to providing users with more natural methods of interacting with virtual environment applications have shown that more than one mode of input can be both beneficial and intuitive as a communication medium between humans and computer applications. Although there are many different modes that could be used in these applications, hand gestures and speech appear to be two of the most logical since users will typically be in environments that will have them immersed in a virtual world with limited access to traditional input devices such as the keyboard or mouse. In this paper, we describe a prototype application, MSVT (Multimodal Scientific Visualization Tool), for visualizing fluid flow around a dataset. MSVT uses a multimodal interface which combines whole-hand and voice input to allow users to visualize and interact with the dataset in a natural manner. A discussion of the various interaction techniques, and the results of an informal user evaluation are presented. KE... | [
261,
2069
] | Train |
258 | 4 | The WristCam as Input Device We show how images of a user's hand from a video camera attached to the underside of the wrist can be processed to yield finger movement information. Discrete (and discreet) movements of the fingers away from a rest position are translated into a small set of base symbols. These are interpreted as input to a wearable computer, providing unobtrusive control. | [
1454
] | Test |
259 | 1 | Pruning Decision Trees with Misclassification Costs . We describe an experimental study of pruning methods for decision tree classifiers when the goal is minimizing loss rather than error. In addition to two common methods for error minimization, CART's cost-complexity pruning and C4.5's error-based pruning, we study the extension of cost-complexity pruning to loss and one pruning variant based on the Laplace correction. We perform an empirical comparison of these methods and evaluate them with respect to loss. We found that applying the Laplace correction to estimate the probability distributions at the leaves was beneficial to all pruning methods. Unlike in error minimization, and somewhat surprisingly, performing no pruning led to results that were on par with other methods in terms of the evaluation criteria. The main advantage of pruning was in the reduction of the decision tree size, sometimes by a factor of ten. While no method dominated others on all datasets, even for the same domain different pruning mechanisms are better for ... | [
724,
3041
] | Train |
260 | 0 | Compiling for Fast State Capture of Mobile Agents Saving, transporting, and restoring the state of a mobile agent is one of the main problems in implementing a mobile agents system. We present an approach, implemented as part of our Messengers system, that represents a trade-off between the unrestricted use of pointers and the ability to perform fully transparent state capture. When writing the code for an agent, the programmer has a choice between two types of functions. C functions are fully general and may use unrestricted pointers, but they are not allowed to invoke any migration commands. Messengers functions may cause migration but their use of pointers is restricted to only a special type of a dynamic array structure. Under these restrictions, the local variables, the program counter, and the calling stack of an agent can all be made machine-independent and can be captured/restored transparently during migration. 1 Introduction Saving, transporting, and restoring the state of a mobile agent is one of the main problem in implem... | [
997
] | Test |
261 | 4 | Speech and Gesture Multimodal Control of a Whole Earth 3D Visualization Environment A growing body of research shows several advantages to multimodal interfaces including increased expressiveness, flexibility, and user freedom. This paper investigates the design of such an interface that integrates speech and hand gestures. The interface has the additional property of operating relative to the user and can be used while the user is in motion or stands at a distance from the computer display. The paper then describes an implementation of the multimodal interface for a whole earth 3D visualization environment which presents navigation interface challenges due to the large magnitude of scale and extended spaces that is available. The characteristics of the multimodal interface are examined, such as speed, recognizability of gestures, ease and accuracy of use, and learnability under likely conditions of use. This implementation shows that such a multimodal interface can be e#ective in a real environment and sets some parameters for the design and use of such interfaces. | [
257,
1854
] | Test |
262 | 3 | Decidable Fragments of First-Order Temporal Logics In this paper, we introduce a new fragment of the first-order temporal language, called the monodic fragment, in which all formulas beginning with a temporal operator (Since or Until) have at most one free variable. We show that the satisfiability problem for monodic formulas in various linear time structures can be reduced to the satisfiability problem for a certain fragment of classical first-order logic. This reduction is then used to single out a number of decidable fragments of first-order temporal logics and of two-sorted first-order logics in which one sort is intended for temporal reasoning. Besides standard first-order time structures, we consider also those that have only finite first-order domains, and extend the results mentioned above to temporal logics of finite domains. We prove decidability in three different ways: using decidability of monadic second-order logic over the intended flows of time, by an explicit analysis of structures with natural numbers time, and by a composition method that builds a model from pieces in finitely many steps. 1 | [
720,
1222,
2297,
2487,
2677,
2802
] | Train |
263 | 2 | Text Database Selection for Longer Queries A metasearch engine is a system that supports unified access to multiple local search engines. One of the main challenges in building a large-scale metasearch engine is to solve the database (search engine) selection problem, which is to efficiently and accurately determine a small number of potentially useful local search engines to invoke for each user query. For the database of each search engine, a representative which indicates approximately the contents of the database is created in advance to enable database selection. The representatives of all databases can be integrated into a single representative to make the selection process more scalable. While an integrated representative with high scalability has just been proposed and has been found to be effective for short queries, its effectiveness for longer queries is significantly lower. In the Internet environment, most queries initially submitted by users are short queries. However, it has been found that better search effectiveness can often be achieved when additional terms are added to the initial queries through query expansion or relevance feedback. The resulting queries are usually longer than the initial queries. In this paper, we propose a new method to construct database representatives and to decide which databases to select for longer queries. Experimental results are given to compare the performance of the new method with that of a previous method. | [
16,
471,
488,
521,
1134,
1642,
1888,
2275,
2464,
2503
] | Train |
264 | 1 | Incremental Learning of Explanation Patterns and their Indices This paper describes how a reasoner can improve its understanding of an incompletely understood domain through the application of what it already knows to novel problems in that domain. Recent work in AI has dealt with the issue of using past explanations stored in the reasoner's memory to understand novel situations. However, this process assumes that past explanations are well understood and provide good "lessons" to be used for future situations. This assumption is usually false when one is learning about a novel domain, since situations encountered previously in this domain might not have been understood completely. Instead, it is reasonable to assume that the reasoner would have gaps in its knowledge base. By reasoning about a new situation, the reasoner should be able to fill in these gaps as new information came in, reorganize its explanations in memory, and gradually evolve a better understanding of its domain. We present a story understanding program that retrieves past explan... | [
225
] | Train |
265 | 1 | Equivalence in Knowledge Representation: Automata, Recurrent Neural Networks, and Dynamical Fuzzy Systems Neurofuzzy systems-the combination of artificial neural networks with fuzzy logic-have become useful in many application domains. However, conventional neurofuzzy models usually need enhanced representation power for applications that require context and state (e.g., speech, time series prediction, control). Some of these applications can be readily modeled as finite state automata. Previously, it was proved that deterministic finite state automata (DFA) can be synthesized by or mapped into recurrent neural networks by directly programming the DFA structure into the weights of the neural network. Based on those results, a synthesis method is proposed for mapping fuzzy finite state automata (FFA) into recurrent neural networks. Furthermore, this mapping is suitable for direct implementation in very large scale integration (VLSI), i.e., the encoding of FFA as a generalization of the encoding of DFA in VLSI systems. The synthesis method requires FFA to undergo a transformation prior to being mapped into recurrent networks. The neurons are provided with an enriched functionality in order to accommodate a fuzzy representation of FFA states. This enriched neuron functionality also permits fuzzy parameters of FFA to be directly represented as parameters of the neural network. We also prove the stability of fuzzy finite state dynamics of the constructed neural networks for finite values of network weight and, through simulations, give empirical validation of the proofs. Hence, we prove various knowledge equivalence representations between neural and fuzzy systems and models of automata. | [
1763
] | Train |
266 | 1 | Using an Explicit Teamwork Model and Learning in RoboCup: An Extended Abstract Stacy Marsella, Jafar Adibi, Yaser Al-Onaizan, Ali Erdem, Randall Hill Gal A. Kaminka, Zhun Qiu, Milind Tambe Information Sciences Institute and Computer Science Department University of Southern California 4676 Admiralty Way, Marina del Rey, CA 90292, USA robocup-sim@isi.edu 1 Introduction The RoboCup research initiative has established synthetic and robotic soccer as testbeds for pursuing research challenges in Artificial Intelligence and robotics. This extended abstract focuses on teamwork and learning, two of the multiagent research challenges highlighted in RoboCup. To address the challenge of teamwork, we discuss the use of a domain-independent explicit model of teamwork, and an explicit representation of team plans and goals. We also discuss the application of agent learning in RoboCup. The vehicle for our research investigations in RoboCup is ISIS (ISI Synthetic), a team of synthetic soccer-players that successfully participated in the simulation league of RoboCup'97, by win... | [
1724,
2492
] | Train |
267 | 1 | Hardware/Software Implementation for Localization and Classification Systems Pattern localization and classification are CPU time intensive being normally implemented in software, however with lower performance than custom implementations. Custom implementation in hardware (ASIC) allows real-time processing, having higher cost and time-to-market than software implementation. We present an alternative that represents a good trade-off between performance and cost. This paper presents initially some systems dealing with object localization and classification, analyzing the performance and implementation of each work. After we propose a system for localization and classification of shapes using reconfigurable devices (FPGA) and a signal processor (DSP) available in a flexible codesign platform. The system will be described using C and VHDL languages, for the software and hardware parts respectively, and has been implemented in an APTIX prototyping platform. 1. | [
2974
] | Validation |
268 | 3 | A Meta Modeling Approach to Workflow Management Systems Supporting Exception Handling Workflow Management Systems (WFMSs) facilitate the definition of structure and decomposition of business processes and assists in management of coordinating, scheduling, executing and monitoring of such activities. Most of the current WFMSs are built on traditional relational database systems and/or using an objectoriented database system for storing the definition and run time data about the workflows. However, a WFMS requires advanced modeling functionalities to support adaptive features, such as on-line exception handling. This article describes our advanced meta-modeling approach using various enabling technologies (such as object orientation, roles, rules, active capabilities) supported by an integrated environment, the ADOME, as a solid basis for a flexible WFMS involving dynamic match making, migrating workflows and exception handling. Copyright 1999 Elsevier Science Ltd Key words: Meta-modeling, Object-Orientation, Workflow Management, Match-Making, Exception Handling, Workflo... | [
822
] | Test |
269 | 4 | SIDE Surfer: a Spontaneous Information Discovery and Exchange System Development of wireless communications enables the rise of networking applications in embedded systems. Web interactions, which are the most spread, are nowadays available on wireless PDAs. Moreover, we can observe a development of ubiquitous computing. Based on this concept, many works aim to consider user's context as part of the parameters of the applications. The context notion can include the user's location, his social activity . . . Taking part from emerging technologies enabling short range and direct wireless communications (which allow to define a proximity context), the aim of our study is to design a new kind of application, extending the Web paradigm: spontaneous and proximate Web interactions. | [
2988
] | Validation |
270 | 2 | MetaSEEk: A Content-Based Meta-Search Engine for Images Search engines are the most powerful resources for finding information on the rapidly expanding World Wide Web (WWW). Finding the desired search engines and learning how to use them, however, can be very time consuming. The integration of such search tools enables the users to access information across the world in a transparent and efficient manner. These systems are called meta-search engines. The recent emergence of visual information retrieval (VIR) search engines on the web is leading to the same efficiency problem. This paper describes and evaluates MetaSEEk, a content-based meta-search engine used for finding images on the Web based on their visual information. MetaSEEk is designed to intelligently select and interface with multiple on-line image search engines by ranking their performance for different classes of user queries. User feedback is also integrated in the ranking refinement. We compare MetaSEEk with a base line version of meta-search engine, which does not use the past performance of the different search engines in recommending target search engines for future queries. | [
152,
224,
489,
583,
1688,
1824,
1858,
2275,
2683,
3031
] | Train |
271 | 1 | Acquisition of Place Knowledge Through Case-Based Learning In this paper we define the task of place learning and describe one approach to this problem. The framework represents distinct places as evidence grids, a probabilistic description of occupancy. Place recognition relies on case-based classification, augmented by a registration process to correct for translations. The learning mechanism is also similar to that in case-based systems, involving the simple storage of inferred evidence grids. Experimental studies with physical and simulated robots suggest that this approach improves place recognition with experience, that it can handle significant sensor noise, that it benefits from improved quality in stored cases, and that it scales well to environments with many distinct places. Previous researchers have studied evidence grids and place learning, but they have not combined these two powerful concepts, nor have they used the experimental methods of machine learning to evaluate their methods' abilities. Keywords: place acquisition, case-b... | [
3144
] | Train |
272 | 4 | Hierarchical Presentation of Expansion Terms Different presentations of candidate expansion terms have not been fully explored in interactive query expansion (IQE). Most existing systems that offer an IQE facility use a list form of presentation. This paper examines an hierarchical presentation of the expansion terms which are automatically generated from a set of retrieved documents, organised in a general to specific manner, and visualised by cascade menus. To evaluate the effectiveness of the presentation, a user test was carried out to compare the hierarchical form with the conventional list form. This shows that users of the hierarchy can complete the expansion task in less time and with fewer terms over those using the lists. Relations between initial query terms and selected expansion terms were also investigated. Keywords Information retrieval, interactive query expansion, concept hierarchies 1. | [
1594,
2535
] | Train |
273 | 5 | Seamless Guidance by Personal Agent in Virtual Space Based on User Interaction in Real World This paper describes a personal agent that guides a visitor through a virtual space by using context, i.e., visitor interaction, in the real world. #Context-aware# guidance in the real world has become an increasingly important research demand since the advent of small and powerful palmtop computers, or PDAs (Personal Digital Assistants), that can obtain useful information about objects in the real world based on context (e.g., current location and visit history) in the real world. We have tried to extend this context-aware guidance into a virtual environment by using context not from the virtual environment but from the real world; such seamless guidance allows visitors to concentrate their attention on the understanding of actual elements. This paper reports our experiment on seamless guidance by a personal agent in a virtual ancient village using real-world context. This was presented at an open house exhibition in our research laboratories. 1 Introduction We have proposed a notion... | [
1216
] | Test |
274 | 3 | Merging Potentially Inconsistent Items of Structured Text Structured text is a general concept that is implicit in a variety of approaches to handling information. Syntactically, an item of structured text is a number of grammatically simple phrases together with a semantic label for each phrase. Items of structured text may be nested within larger items of structured text. The semantic labels in a structured text are meant to parameterize a stereotypical situation, and so a particular item of structured text is an instance of that stereotypical situation. Much information is potentially available as structured text including tagged text in XML, text in relational and object-oriented databases, and the output from information extraction systems in the form of instantiated templates. In this paper, we formalize the concept of structured text, and then focus on how we can identify inconsistency in the logical representation of items of structured text. We then present a new framework for merging logical theories that can be employed t... | [
1443,
1632,
1843
] | Train |
275 | 0 | MARS: a Programmable Coordination Architecture for Mobile Agents Mobile agents represent a promising technology for the development of Internet applications. However, mobile computational entities introduce peculiar problems w.r.t. the coordination of the application components. The paper outlines the advantages of Linda-like coordination models, and shows how a programmable coordination model based on reactive tuple spaces can provide further desirable features for Internet applications based on mobile agents. Accordingly, the paper presents the design and the implementation of the MARS coordination architecture for Java-based mobile agents. MARS defines Linda-like tuple spaces, which can be programmed to react with specific actions to the accesses made by mobile agents. | [
245,
532,
666,
915,
1062,
1065,
1390,
1795,
2576,
2693
] | Train |
276 | 2 | Text-Based Content Search and Retrieval in ad hoc P2P Communities We consider the problem of content search and retrieval in peer-to-peer (P2P) communities. P2P computing is a potentially powerful model for information sharing between ad hoc groups' of users because of its' low cost of entry and natural model for resource scaling with community size. As P2P communities grow in size, however, locating information distributed across the large number of peers becomes problematic. We present a distributed text-based content search and retrieval algorithm to address this' problem. Our algorithm is' based on a state-of-the-art text-based document ranking algorithm: the vector-space model instantiated with the TFxlDF ranking rule. A naive application of TFxlDF wouM require each peer in a community to collect an inverted index of the entire community. This' is' costly both in terms of bandwidth and storage. Instea & we show how TFxlDF can be approximated given compact summaries of peers' local inverted indexes. We make three contributions: (a) we show how the TFxlDF rule can be adapted to use the index summaries, (b) we provide a heuristic for adaptively determining the set of peers that shouM be contacted for a query, and (c) we show that our algorithm tracks' TFxlDF's performance very closely, regardless of how documents' are distributed throughout the community. Furthermore, our algorithm preserves the main flavor of TFxlDF by retrieving close to the same set of documents for any given query. | [
1505,
2503
] | Train |
277 | 1 | Projective Rotations applied to a Pan-Tilt Stereo Head A non-metric pan-tilt stereo-head consists of a weakly calibrated stereo rig mounted on a pan-tilt mechanism. It is called non-metric since neither the kinematics of the mechanism, nor camera calibration are required. The Lie group of "projective rotations"- homographies of projective space corresponding to pure rotations -- is an original formalism to model the geometry of such a pan-tilt system. A Rodrigues alike formula as well as a minimal parameterization of projective rotations are introduced. Based on this, the practical part devises a numerical optimization technique for accurately estimating projective rotations from point correspondences, only. This procedure recovers sufficient geometry to operate the system. The experiments validate and evaluate the proposed approach on real image data. They show the weak calibration, image prediction, and homing of a non-metric pan-tilt head. 1 Introduction One of the most useful sensors in computer vision is a pan and tilt stereo head. ... | [
2142
] | Train |
278 | 0 | Cooperating Mobile Agents for Dynamic Network Routing this paper we present a contrasting model, a dynamic, wireless, peer to peer network with routing tasks performed in a decentralized and distributed fashion by mobile software agents that cooperate to accumulate and distribute connectivity information. Our agents determine system topology by exploring the network, then store this information in the nodes on the network. Other agents use this stored information to derive multi-hop routes across the network. We study these algorithms in simulation as an example of using populations of mobile agents to manage networks | [
81,
1173,
1515,
2542
] | Validation |
279 | 3 | Optimization Techniques For Queries with Expensive Methods Object-Relational database management systems allow knowledgeable users to de ne new data types, as well as new methods (operators) for the types. This exibility produces an attendant complexity, which must be handled in new ways for an Object-Relational database management system to be e cient. In this paper we study techniques for optimizing queries that contain time-consuming methods. The focus of traditional query optimizers has been on the choice of join methods and orders; selections have been handled by \pushdown " rules. These rules apply selections in an arbitrary order before as many joins as possible, using the assumption that selection takes no time. However, users of Object-Relational systems can embed complex methods in selections. Thus selections may take signi cant amounts of time, and the query optimization model must be enhanced. In this paper, we carefully de ne a query cost framework that incorporates both selectivity and cost estimates for selections. We develop an algorithm called Predicate Migration, and prove that it produces optimal plans for queries with expensive methods. We then describe our implementation of Predicate Migration in the commercial Object-Relational database management system Illustra, and discuss practical issues that a ect our earlier assumptions. We compare Predicate Migration to a variety of simpler optimization techniques, and demonstrate that Predicate Migration is the best general solution to date. The alternative techniques we presentmaybe useful for constrained workloads. | [
230,
2022,
2149
] | Train |
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