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1,580 | 0 | Configuration Management for Multi-Agent Systems As heterogeneous distributed systems, multi-agent systems present some challenging configuration management issues. There are the problems of knowing how to allocate agents to computers, launch them on remote hosts, and once the agents have been launched, how to monitor their runtime status so as to manage computing resources effectively. In this paper, we present the RETSINA Configuration Manager, RECoMa. We describe its architecture, how it uses agent infrastructure such as service discovery, to assist the multi-agent system administrator in allocating, launching, and monitoring a heterogeneous distributed agent system in a distributed and networked computing environment. 1 1. | [
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1,581 | 3 | Semantics Of (disjunctive) Logic Programs Based On Partial Evaluation SEMANTICS AND TRANSFORMATIONS In this paper, we consider allowed disjunctive DATALOG : programs over some fixed function-free finite signature \Sigma. In fact, in the semantical part of this paper, we consider only the ground instantiation of the programs, because we claim that any sensible semantics should assign the same meaning to a program P and its instantiation ground(P ). So the variables are seen only as a shorthand for denoting ground programs in a more compact way. This means that in the semantical part, we could as well have worked with propositional programs. However, in the computational part, it would be very inefficient to compute first the ground instantiation of the given program. Here we make use of the allowedness condition: every variable of the rule must occur also in a positive body literal. This guarantees that in every rule application, all variables are bound to a constant. It is 5 true that in this way we again manage to consider only ground programs. But... | [
226,
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1,582 | 3 | Extensible and Similarity-based Grouping for Data Integration Data integration as required in a variety of applications like data warehousing, information system integration etc. makes great demands regarding features to deal with overlapping and inconsistent data. Object-relational and other data management systems available today provide only limited concepts to deal with these requirements. The general concept of grouping and aggregation appears to be a fitting paradigm for various of the current issues in data integration, but in its common form of equality-based grouping a number of problems remain unsolved. Various extensions to this concept have been introduced over the last years regarding user-defined functions for aggregation and grouping. | [
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1,583 | 0 | Automatic translation of PARADIGM models into PLTL-based Software systems have evolved from monolythic programs to systems constructed from parallel, cooperative components, as can be currently found in objectoriented applications. Although powerfull, these cooperative systems are also more di#cult to verify. | [
780
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1,584 | 4 | An Introduction to 3-D User Interface Design Three-dimensional user interface design is a critical component of any virtual environment (VE) application. In this paper, we present a broad overview of 3-D interaction and user interfaces. We discuss the effect of common VE hardware devices on user interaction, as well as interaction techniques for generic 3-D tasks and the use of traditional 2-D interaction styles in 3-D environments. We divide most userinteraction tasks into three categories: navigation, selection/manipulation, and system control. Throughout the paper, our focus is on presenting not only the available techniques but also practical guidelines for 3-D interaction design and widely held myths. Finally, we briefly discuss two approaches to 3-D interaction design and some example applications with complex 3-D interaction requirements. We also present an annotated online bibliography as a reference companion to this article. | [
79,
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1,585 | 4 | Guiding User Navigation in Virtual Environments Using Awareness of Virtual Off-Screen Space Navigation in virtual environments can be difficult. One contributing factor is the problem of user disorientation. Two major causes of this are the lack of navigation cues in the environment and problems with navigating too close to or through virtual world objects. Previous work has developed guidelines, informed by cinematography conventions, for the construction of virtual environments to aid user comprehension of virtual "space" to reduce user disorientation. This paper describes the validation of these guidelines via a user study involving a navigation task in a virtual "maze". Results suggest that the use of the guidelines can help reduce the incidences of user disorientation. However, the guidelines seemed to have little impact on users' abilities to construct 'cognitive maps' of the environment. | [
810,
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1,586 | 2 | On Computing Functions with Uncertainty We study the problem of computing a function f(x1;:::; xn) giv en that the actual values of the variables xi's are kno wn only with some uncertainty. F or each variable xi, aninterval Ii is kno wn such that the value of xi is guaranteed to fall within this interval. Any such interval can be probed to obtain the actual value of the underlying variable; how ever, there is a cost associated with each suc h probe. The goal is to adaptively iden tify a minimum cost sequence of probes suc h that regardless of the actual values tak en b y the unprobed xi's, the v alue of the functionf can be computed to within a speci ed precision. We design online algorithms for this problem when f is either the selection function or an aggregation function such as sum or average. We consider three natural models of precision and give algorithms for each model. We analyze our algorithms in the framework of competitive analysis and sho w that our algorithms are asymptotically optimal. Finally, we also study online algorithms for functions that are obtained by composing together selection and aggregation functions. 1. | [
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1,587 | 4 | A Semantics of Contrast and Information Structure for Specifying Intonation in Spoken Language Generation In this dissertation I present a model for the determination of intonation contours from context and provide two implemented systems which apply this theory to the problem of generating spoken language with appropriate intonation from high-level semantic representations. The theory and implementations presented here are based on an information structure framework that mediates between intonation and discourse, and encodes the proper level of semantic information to account for both contextually-bound accentuation patterns and intonational phrasing. The structural similarities among these linguistic levels of representation are the basis for selecting Combinatory Categorial Grammar #CCG, Steedman 1985,1990a# as the model for spoken language production. This model licenses congruent syntactic, prosodic and information structural constituents and consequently represents a simpli#cation over models of prosody developed in syntactically more traditional frameworks. The previous mention heu... | [
1111,
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1,588 | 4 | i-LAND: An interactive Landscape for Creativity and Innovation We describe the i-LAND environment which constitutes an example of our vision of the workspaces of the future, in this case supporting cooperative work of dynamic teams with changing needs. i-LAND requires and provides new forms of human-computer interaction and new forms of computer-supported cooperative work. Its design is based on an integration of information and architectural spaces, implications of new work practices and an empirical requirements study informing our design. i-LAND consists of several ‘roomware ’ components, i.e. computer-augmented objects integrating room elements with information technology. We present the current realization of i-LAND in terms of an interactive electronic wall, an interactive table, two computer-enhanced chairs, and two “bridges ” for the Passage-mechanism. This is complemented by the description of the creativity support application and the technological infrastructure. The paper is accompanied by a video figure in the CHI’99 video program. | [
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1,589 | 1 | Training Reinforcement Neurocontrollers Using The Polytope Algorithm A new training algorithm is presented for delayed reinforcement learning problems that does not assume the existence of a critic model and employs the polytope optimization algorithm to adjust the weights of the action network so that a simple direct measure of the training performance is maximized. Experimental results from the application of the method to the pole balancing problem indicate improved training performance compared with critic-based and genetic reinforcement approaches. Keywords: reinforcement learning, neurocontrol, optimization, polytope algorithm, pole balancing, genetic reinforcement. TRAINING REINFORCEMENT NEUROCONTROLLERS USING THE POLYTOPE ALGORITHM Abstract A new training algorithm is presented for delayed reinforcement learning problems that does not assume the existence of a critic model and employs the polytope optimization algorithm to adjust the weights of the action network so that a simple direct measure of the training performance is maximized. Exper... | [
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1,590 | 1 | MetaCost: A General Method for Making Classifiers Cost-Sensitive Research in machine learning, statistics and related fields has produced a wide variety of algorithms for classification. However, most of these algorithms assume that all errors have the same cost, which is seldom the case in KDD prob- lems. Individually making each classification learner costsensitive is laborious, and often non-trivial. In this paper we propose a principled method for making an arbitrary classifier cost-sensitive by wrapping a cost-minimizing procedure around it. This procedure, called MetaCost, treats the underlying classifier as a black box, requiring no knowledge of its functioning or change to it. Unlike stratification, MetaCost is applicable to any number of classes and to arbitrary cost matrices. Empirical trials on a large suite of benchmark databases show that MetaCost almost always produces large cost reductions compared to the cost-blind classifier used (C4.5RULES) and to two forms of stratification. Further tests identify the key components of MetaCost and those that can be varied without substantial loss. Experiments on a larger database indicate that MetaCost scales well. | [
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1,591 | 2 | Digital Libraries and Autonomous Citation Indexing The World Wide Web is revolutionizing the way that researchers access scientific information. Articles are increasingly being made available on the homepages of authors or institutions, at journal Web sites, or in online archives. However, scientific information on the Web is largely disorganized. This article introduces the creation of digital libraries incorporating Autonomous Citation Indexing (ACI). ACI autonomously creates citation indices similar to the Science Citation Index R . An ACI system autonomously locates articles, extracts citations, identifies identical citations that occur in different formats, and identifies the context of citations in the body of articles. ACI can organize the literature and provide most of the advantages of traditional citation indices, such as literature search using citation links, and the evaluation of articles based on citation statistics. Furthermore, ACI can provide significant advantages over traditional citation indices. No manual effort is required for indexing, which should result in a reduction in cost and an increase in the availability of citation indices. An ACI system can also provide more comprehensive and up-to-date indices of the literature by indexing articles on the Web, technical reports, conference papers, etc. Furthermore, ACI makes it easy to browse the context of citations to given articles, allowing researchers to quickly and easily see what subsequent researchers have said about a given article. digital libraries incorporating ACI may significantly improve scientific dissemination and feedback. | [
488,
1108,
1755,
2178,
2631,
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2957,
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1,592 | 1 | Optimizing Global-Local Search Hybrids This paper develops a framework for optimizing global-local hybrids of search or optimization procedures. The paper starts by idealizing the search problem as a search by a global algorithm G for either (1) acceptable targets---solutions that meet a specified criterion---or for (2) basins of attraction that then lead to acceptable targets under a specified local search algorithm L. The paper continues by abstracting two sets of parameters, probabilities of successfully hitting targets and basins and time-to-criterion coefficients. With these parameters, equations may be written to account for the total time of search and for the probabilistic success (reliability) in reaching an acceptable solution. Thereafter, optimization problems are formulated in which the division of local versus global search time is optimized so that solution time to acceptable reliability is minimized or reliability under specified solution time is maximized. A two-basin optimality criterion is derived and appl... | [
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1,593 | 5 | AI at IBM Research IBM has played an active role in AI research since the field's inception more than 50 years ago. In a trend that reflects the increasing demand for applications that behave intelligently, IBM today carries out most AI research in an interdisciplinary fashion by combining AI techniques with other computing techniques to solve difficult technical problems. 1 | [
365,
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1,594 | 4 | Query Expansion Using an Interactive Concept Hierarchy Query expansion is the process of supplementing an original query with additional terms in order to refine a search and increase retrieval effectiveness. If the query expansion is interactive, then the user and the system work together to expand the query. The system usually suggests possible expansion terms and the user selects those they wish to add to the query. Studies have shown that interactive query expansion has the potential to improve retrieval effectiveness, but that it rarely succeeds in achieving its potential. It has been shown that users desire some control over the expansion process. In order to achieve this, the functionality of the system must be represented on the user interface in a comprehensible way. The main aim of this study is to focus on a small aspect of the interface and investigate whether the method used to present potential query expansion terms has any effect on retrieval effectiveness. The tool tested in this study automatically generates a hierarchical... | [
272
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1,595 | 2 | Comparing Top k Lists Motivated by several applications, we introduce various distance measures between “top k lists.” Some of these distance measures are metrics, while others are not. For each of these latter distance measures, we show that they are “almost ” a metric in the following two seemingly unrelated aspects: (i) they satisfy a relaxed version of the polygonal (hence, triangle) inequality, and (ii) there is a metric with positive constant multiples that bound our measure above and below. This is not a coincidence—we show that these two notions of almost being a metric are formally identical. Based on the second notion, we define two distance measures to be equivalent if they are bounded above and below by constant multiples of each other. We thereby identify a large and robust equivalence class of distance measures. Besides the applications to the task of identifying good notions of (dis-)similarity between two top k lists, our results imply polynomial-time constant-factor approximation algorithms for the rank aggregation problem [DKNS01] with respect to a large class of distance measures. To appear in SIAM J. on Discrete Mathematics. Extended abstract to appear in 2003 ACM-SIAM Symposium on Discrete Algorithms (SODA ’03). | [
2701
] | Train |
1,596 | 5 | A Comparison Between Two Neural Network Rule Extraction Techniques for the Diagnosis of Hepatobiliary Disorders Neural networks have been widely used as tools for prediction in medicine. We expect to see even more applications of neural networks for medical diagnosis as recently developed neural network rule extraction algorithms make it possible for the decision process of a trained network to be expressed as classification rules. These rules are more comprehensible to a human user than the classification process of the networks which involves complex nonlinear mapping of the input data. This paper reports the results from two neural network rule extraction techniques, NeuroLinear and NeuroRule applied to the diagnosis of hepatobiliary disorders. The data set consists of nine measurements collected from patients in a Japanese hospital and these measurements have continuous values. NeuroLinear generates piece-wise linear discriminant functions for this data set. The continuous measurements have previously been discretized by domain experts. NeuroRule is applied to the discretized data... | [
1626
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1,597 | 2 | Two Decades Of Statistical Language Modeling: Where Do We Go From Here? Statistical Language Models estimate the distribution of various natural language phenomena for the purpose of speech recognition and other language technologies. Since the first significant model was proposed in 1980, many attempts have been made to improve the state of the art. We review them here, point to a few promising directions, and argue for a Bayesian approach to integration of linguistic theories with data. 1. OUTLINE Statistical language modeling (SLM) is the attempt to capture regularities of natural language for the purpose of improving the performance of various natural language applications. By and large, statistical language modeling amounts to estimating the probability distribution of various linguistic units, such as words, sentences, and whole documents. Statistical language modeling is crucial for a large variety of language technology applications. These include speech recognition (where SLM got its start), machine translation, document classification and routing, optical character recognition, information retrieval, handwriting recognition, spelling correction, and many more. In machine translation, for example, purely statistical approaches have been introduced in [1]. But even researchers using rule-based approaches have found it beneficial to introduce some elements of SLM and statistical estimation [2]. In information retrieval, a language modeling approach was recently proposed by [3], and a statistical/information theoretical approach was developed by [4]. SLM employs statistical estimation techniques using language training data, that is, text. Because of the categorical nature of language, and the large vocabularies people naturally use, statistical techniques must estimate a large number of parameters, and consequently depend critically on the availability of large amounts of training data. | [
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1,598 | 4 | Steps Toward Accommodating Variable Position Tracking Accuracy in a Mobile Augmented Reality System The position-tracking accuracy of a location-aware mobile system can change dynamically as a function of the user's location and other variables specific to the tracker technology used. This is especially problematic for mobile augmented reality systems, which ideally require extremely precise position tracking for the user's head, but which may not always be able to achieve the necessary level of accuracy. While it is possible to ignore variable positional accuracy in an augmented reality user interface, this can make for a confusing system; for example, when accuracy is low, virtual objects that are nominally registered with real ones may be too far off to be of use. | [
664,
1186,
1757,
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1,599 | 3 | Administering Permissions for Distributed Data: Factoring and Automated Inference We extend SQL's grant/revoke model to handle all administration of permissions in a distributed database. The key idea is to "factor" permissions into simpler decisions that can be administered separately, and for which we can devise sound inference rules. The model enables us to simplify administration via separation of concerns (between technical DBAs and domain experts), and to justify fully automated inference for some permission factors. We show how this approach would coexist with current practices based on SQL permissions. Keywords: Access permissions, derived data, view, federation, warehouse 1 | [
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1,600 | 3 | Path Constraints on Semistructured and Structured Data We present a class of path constraints of interest in connection with both structured and semi-structured databases, and investigate their associated implication problems. These path constraints are capable of expressing natural integrity constraints that are not only a fundamental part of the semantics of the data, but are also important in query optimization. We show that in semistructured databases, despite the simple syntax of the constraints, their associated implication problem is r.e. complete and finite implication problem is co-r.e. complete. However, we establish the decidability of the implication problems for several fragments of the path constraint language, and demonstrate that these fragments suffice to express important semantic information such as inverse relationships and local database constraints commonly found in object-oriented databases. We also show that in the presence of types, the analysis of path constraint implication becomes more delicate. We demonstrate so... | [
44,
242,
382,
1036,
1318,
1913,
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1,601 | 1 | Employing EM and Pool-Based Active Learning for Text Classification This paper shows how a text classifier's need for labeled training data can be reduced by a combination of active learning and Expectation Maximization (EM) on a pool of unlabeled data. Query-by-Committee is used to actively select documents for labeling, then EM with a naive Bayes model further improves classification accuracy by concurrently estimating probabilistic labels for the remaining unlabeled documents and using them to improve the model. We also present a metric for better measuring disagreement among committee members; it accounts for the strength of their disagreement and for the distribution of the documents. Experimental results show that our method of combining EM and active learning requires only half as many labeled training examples to achieve the same accuracy as either EM or active learning alone. Keywords: text classification active learning unsupervised learning information retrieval 1 Introduction In many settings for learning text classifiers, obtaining lab... | [
759,
1579,
2100,
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1,602 | 3 | Querying Temporal Constraint Networks in PTIME We start with the assumption that temporal knowledge usually captured by constraint networks can be represented and queried more effectively by using the scheme of indefinite constraint databases proposed by Koubarakis. Although query evaluation in this scheme is in general a hard computational problem, we demonstrate that there are several interesting cases where query evaluation can be done in PTIME. These tractability results are original and subsume previous results by van Beek, Brusoni, Console and Terenziani. Introduction When temporal constraint networks are used in applications, their nodes represent the times when certain facts are true, or when certain events take place, or when events start or end. By labeling nodes with appropriate natural language expressions (e.g., breakfast or walk) and arcs by temporal relations, temporal constraint networks can be queried in useful ways. For example the query "Is it possible (or certain) that event walk happened after event breakfast... | [
1024
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1,603 | 1 | Autonomous Learning of Sequential Tasks: Experiments and Analyses : This paper presents a novel learning model Clarion, which is a hybrid model based on the twolevel approach proposed in Sun (1995). The model integrates neural, reinforcement, and symbolic learning methods to perform on-line, bottom-up learning (i.e., learning that goes from neural to symbolic representations). The model utilizes both procedural and declarative knowledge (in neural and symbolic representations respectively), tapping into the synergy of the two types of processes. It was applied to deal with sequential decision tasks. Experiments and analyses in various ways are reported that shed light on the advantages of the model. obstacles agent target Figure 1: Navigating Through A Minefield 1 Introduction This paper presents a model that unifies neural, symbolic, and reinforcement learning. It addresses the following three issues: (1) It deals with autonomous learning: It allows a situated agent to learn autonomously and continuously, from on-going experience in the world, w... | [
472,
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1,604 | 0 | Feasible Formation of Coalitions Among Autonomous Agents in Non-Super-Additive Environments Cooperating and sharing resources by creating coalitions of agents are an important way for autonomous agents to execute tasks and to maximize payoff. Such coalitions will form only if each member of a coalition gains more if it joins the coalition than it could gain otherwise. There are several ways of creating such coalitions and dividing the joint payoff among the members. In this paper we present algorithms for coalition formation and payoff distribution in non-super-additive environments. We focus on a low-complexity kernel-oriented coalition formation algorithm. The properties of this algorithm were examined via simulations. These have shown that the model increases the benefits of the agents within a reasonable time period, and more coalition formations provide more benefits to the agents. Key Words Distributed AI, Coalition Formation, Multi-Agent Systems. This material is based upon work supported in part by the NSF under grant No. IRI-9423967, ARPA/Rome Labs contract F30602... | [
106,
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1,605 | 0 | Transaction Oriented Computational Models For Multi-Agent Systems BDI (Belief, Desire, Intention) is a mature and commonly adopted architecture for Intelligent Agents. However, the current computational model adopted by BDI has a number of problems with concurrency control, recoverability and predictability. This has hindered the construction of agents having robust and predictable behaviour. Indeed the conceptual and practical tools needed for building dependable agent systems, resilient to faults and other unexpected situations, are still at an early stage of research. | [
1113,
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] | Validation |
1,606 | 0 | A Classification Scheme for Negotiation in Electronic Commerce In the last few years we have witnessed a surge of business-to-consumer and business-to-business commerce operated on the Internet. However many of these systems are often nothing more than electronic catalogues on which the user can choose a product which is made available for a fixed price. This modus operandi is clearly failing to exploit the full potential of electronic commerce. Against this background, we argue here that in the next few years we will see a new generation of systems emerge, based on automatic negotiation. In this paper we identify the main parameters on which any automatic negotiation depends. This classification schema is then used to categorise the subsequent papers in this book that focus on automatic negotiation. | [
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1,607 | 4 | Wearable Computing and the Remembrance Agent This paper gives an overview of the field of wearable computing. It covers the key differences between wearables and other portable computers, and discusses issues with the design and application for wearables. There then follows a specific example, the wearable remembrance agent --- a proactive memory aid. The paper concludes with discussion of future directions for research and applications inspired by using the prototype. 1. Introduction This scenario may sound some way off in practical terms, but it is not. All the technologies needed to support it are available. It is the aim of this paper to describe some of these technologies in more detail and give an indication of their current status. The paper will start by describing features available in wearable computers that are not available in current laptops or personal digital assistants (PDAs). It will then go on to describe a number of other general application areas for wearables and current wearable technologies and design needs. This is followed by a description of the remembrance agent (RA), a wearable memory aid that continually reminds the wearer of potentially relevant information based on the wearer's current physical and virtual context. Finally, the paper discusses extensions that are being added to the current prototype system. 2. What are wearable computers? The fuzzy definition of a wearable computer is that it is a computer that is always with the user, is comfortable and easy to keep and use, and is as unobtrusive as clothing. However, this `smart clothing' definition is unsatisfactory when the details are considered. Most importantly, it does not convey how a wearable computer is any different from a very small palm-top. A more specific definition is that wearable computers have many of the followin... | [
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1,608 | 2 | KEA: Practical Automatic Keyphrase Extraction Keyphrases provide semantic metadata that summarize and characterize documents. This paper describes Kea, an algorithm for automatically extracting keyphrases from text. Kea identifies candidate keyphrases using lexical methods, calculates feature values for each candidate, and uses a machine -learning algorithm to predict which candidates are good keyphrases. The machine learning scheme first builds a prediction model using training documents with known keyphrases, and then uses the model to find keyphrases in new documents. We use a large test corpus to evaluate Kea's effectiveness in terms of how many author-assigned keyphrases are correctly identified. The system is simple, robust, and publicly available. INTRODUCTION Keyphrases provide a brief summary of a document's contents. As large document collections such as digital libraries become widespread, the value of such summary information increases. Keywords and keyphrases 1 are particularly useful because they can be interpret... | [
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1,609 | 2 | Agents in Delivering Personalized Content Based on Semantic Metadata In the SmartPush project professional editors add semantic metadata to information flow when the content is created. This metadata is used to filter the information flow to provide the end users with a personalized news service. Personalization and delivery process is modeled as software agents, to whom the user delegates the task of sifting through incoming information. The key components of the SmartPush architecture have been implemented, and the focus in the project is shifting towards a pilot implementation and testing the ideas in practice. Introduction Internet and online distribution are changing the rules of professional publishing. Physical constraints of media products are not any more the key factors in the publishing process. In newspaper publishing, the bottleneck was what could fit in the paper. Today publishers are capable of creating more content, but they need new methods for personalized distribution. Incremental price for publishing on the Internet is neg... | [
2007,
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1,610 | 4 | Designing Storytelling Technologies to Encourage Collaboration Between Young Children We describe the iterative design of two collaborative storytelling technologies for young children, KidPad and the Klump. We focus on the idea of designing interfaces to subtly encourage collaboration so that children are invited to discover the added benefits of working together. This idea has been motivated by our experiences of using early versions of our technologies in schools in Sweden and the UK. We compare the approach of encouraging collaboration with other approaches to synchronizing shared interfaces. We describe how we have revised the technologies to encourage collaboration and to reflect design suggestions made by the children themselves. Keywords Children, Single Display Groupware (SDG), Computer Supported Cooperative Work (CSCW), Education, Computer Supported Collaborative Learning (CSCL). INTRODUCTION Collaboration is an important skill for young children to learn. Educational research has found that working in pairs or small groups can have beneficial effects on l... | [
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1,611 | 4 | Towards a Living Lab research facility and a ubiquitous computing research programme Introduction My interest in the topic of this workshop stems from my current involvement in setting up a new research facility at the Eindhoven University of Technology. This facility is called the 'Living Lab', and is quite similar to related projects around the globe in that it aims to study how people experience a ubiquitous computing environment, when they will inhabit it and use it for prolonged periods of time. The slogan of this development, is 'Vacation on Campus'. The project is currently at the initiation phase. We have proposed a white paper [1] describing the concept and the research programme, and we are currently working to involve stakeholders from different departments of the TU/e, e.g., Architecture, Electrical Engineering, and Technology Management, and of the local industry. (E.g., Philips). In the remaining of this position paper, I outline our research concept and our programme. Concept - Vacation on Campus The Living Lab, will be a cros | [
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1,612 | 3 | Theory of Answering Queries Using Views The problem of answering queries using views is to nd ecient methods of answering a query using a set of previously materialized views over the database, rather than accessing the database relations. The problem has recently received signicant attention because of its relevance to a wide variety of data management problems, such as query optimization, the maintenance of physical data independence, data integration and data warehousing. This article surveys the theoretical issues concerning the problem of answering queries using views. 1 | [
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1,613 | 4 | Combining the Self-Organizing Map and K-Means Clustering for On-line Classification of Sensor Data Many devices, like mobile phones, use contextual profiles like "in the car" or "in a meeting" to quickly switch between behaviors. Achieving automatic context detection, usually by analysis of small hardware sensors, is a fundamental problem in human-computer interaction. However, mapping the sensor data to a context is a difficult problem involving near real-time classification and training of patterns out of noisy sensor signals. This paper proposes an adaptive approach that uses a Kohonen Self-Organizing Map, augmented with on-line k-means clustering for classification of the incoming sensor data. Overwriting of prototypes on the map, especially during the untangling phase of the Self-Organizing Map, is avoided by a refined k-means clustering of labeled input vectors. | [
2225
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1,614 | 0 | CAST: Collaborative Agents for Simulating Teamwork Psychological studies on teamwork have shown that an effective team often can anticipate information needs of teammates based on a shared mental model. Existing multi-agent models for teamwork are limited in their ability to support proactive information exchange among teammates. To address this issue, we have developed and implemented a multi-agent architecture called CAST that simulates teamwork and supports proactive information exchange in a dynamic environment. We present a formal model for proactive information exchange. Knowledge regarding the structure and process of a team is described in a language called MALLET. Beliefs about shared team processes and their states are represented using Petri Nets. Based on this model, CAST agents offer information proactively to those who might need it using an algorithm called DIARG. Empirical evaluations using a multi-agent synthetic testbed application indicate that CAST enhances the effectiveness of teamwork among agents without sacrificing a high cost for communications. 1 | [
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1,615 | 3 | Approximate Nearest Neighbor Searching in Multimedia Databases In this paper, we develop a general framework for approximate nearest neighbor queries. We categorize the current approaches for nearest neighbor query processing based on either their ability to reduce the data set that needs to be examined, or their ability to reduce the representation size of each data object. We first propose modifications to wellknown techniques to support the progressive processing of approximate nearest neighbor queries. A user may therefore stop the retrieval process once enough information has been returned. We then develop a new technique based on clustering that merges the benefits of the two general classes of approaches. Our cluster-based approach allows a user to progressively explore the approximate results with increasing accuracy. We propose a new metric for evaluation of approximate nearest neighbor searching techniques. Using both the proposed and the traditional metrics, we analyze and compare several techniques with a detailed performance evaluation. We demonstrate the feasibility and efficiency of approximate nearest neighbor searching. We perform experiments on several real data sets and establish the superiority of the proposed cluster-based technique over the existing techniques for approximate nearest neighbor searching. 1 | [
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1,616 | 0 | Model Checking Multiagent Systems Model checking is a very successful technique which has been applied in the design and verification of finite state concurrent reactive processes. In this paper we show how this technique can be lifted to be applicable to multiagent systems. Our approach allows us to reuse the technology and tools developed in model checking, to design and verify multiagent systems in a modular and incremental way, and also to have a very efficient model checking algorithm. 1 Introduction Model checking is a very successful automatic technique which has been devised for the design and verification of finite state reactive systems, e.g., sequential circuit designs, communication protocols, and safety critical control systems (see, e.g., [2]). There is evidence that model checking, when applicable, is far more successful than the other approaches to formal methods and verification (e.g., first order or inductive theorem proving, tableau based reasoning about modal satisfiability). Nowadays many very eff... | [
84,
1724,
1899,
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] | Train |
1,617 | 0 | Communicating Agents We study the problem of endowing logic-based agents that can reason about their own beliefs as well as the beliefs of other agents with communication skills. We show how communication performatives from existing agent communication languages as well as their preconditions and eects can be expressed within logic-based agents in terms of the agents' beliefs. We illustrate the resulting language for programming logic-based agents by means of examples. 1 Introduction In an earlier paper [6], we propose an approach to logic-based agents by combining the approach to agents by Kowalski and Sadri [11] and the approach to meta-reasoning by Costantini et al. [5, 4]. Similarly to Kowalski and Sadri's agents, the agents in [6] are hybrid in that they exhibit both rational (or deliberative) and reactive behaviour. The reasoning core of the agents is a proof procedure that combines forward and backward reasoning. Backward reasoning is used primarily for planning, problem solving and other deliber... | [
622,
1192
] | Train |
1,618 | 4 | The Open Agent Architecture: A Framework for Building Distributed Software Systems The Open Agent Architecture (OAA), developed and used for several years at SRI International, makes it possible for software services to be provided through the cooperative efforts of distributed collections of autonomous agents. Communication and cooperation between agents are brokered by one or more facilitators, which are responsible for matching requests, from users and agents, with descriptions of the capabilities of other agents. Thus, it is not generally required that a user or agent know the identities, locations, or number of other agents involved in satisfying a request. OAA is structured so as to minimize the effort involved in creating new agents and "wrapping" legacy applications, written in various languages and operating on various platforms; to encourage the reuse of existing agents; and to allow for dynamism and flexibility in the makeup of agent communities. Distinguishing features of OAA as compared with related work include extreme flexibility in using facilitator-b... | [
1498,
2249,
2313,
2514,
3103,
3169
] | Train |
1,619 | 4 | A Digital Photography Framework Enabling Affective Awareness in Home Communication By transforming the personal computer into a communication appliance, the Internet has initiated the true home computing revolution. As a result, Computer Mediated Communication (CMC) technologies are increasingly used in domestic settings, and are changing the way people keep in touch with their relatives and friends. This article first looks at how CMC tools are currently used in the home, and points at some of their benefits and limitations. Most of these tools support explicit interpersonal communication, by providing a new medium for sustaining conversations. The need for tools supporting implicit interaction between users, in more natural and effortless ways, is then argued for. The idea of affective awareness is introduced as a general sense of being in touch with one's family and friends. Finally, the KAN-G framework, which enables affective awareness through the exchange of digital photographs, is described. Various components, which make the capture, distribution, observation... | [
180,
708
] | Train |
1,620 | 0 | Methodologies for PVC Configuration in Heterogeneous ATM Environments Using Intelligent Mobile Agents Traditionally, the functionality enabling the configuration of Permanent Virtual Connections (PVCs) in heterogeneous Asynchronous Transfer Mode (ATM) environments has been accomplished through the use of client/server technologies. However, this approach suffers from a number of problems in the areas of flexibility, extensibility and efficiency, and as networks become increasingly complex and dynamic, the need for a new paradigm has become apparent. This paper is concerned with the analysis of a proposed solution wherein intelligent mobile agents are utilized to provide autonomous network configuration management functionality. Configuration methodologies based on a single mobile agent acting serially and multiple mobile agents acting in parallel are compared in terms of time duration and network load. The use of a small expert system to provide the intelligence needed to handle error situations is investigated. A test environment composed of three simulated ATM switch nodes is develop... | [
146
] | Train |
1,621 | 2 | Building Efficient Wireless Sensor Networks with Low-Level Naming In most distributed systems, naming of nodes for low-level communication leverages topological location (such as node addresses) and is independent of any application. In this paper, we investigate an emerging class of distributed systems where low-level communication does not rely on network topological location. Rather, low-level communication is based on attributes that are external to the network topology and relevant to the application. When combined with dense deployment of nodes, this kind of named data enables in-network processing for data aggregation, collaborative signal processing, and similar problems. These approaches are essential for emerging applications such as sensor networks where resources such as bandwidth and energy are limited. This paper is the first description of the software architecture that supports named data and in-network processing in an operational, multi-application sensor-network. We show that approaches such as in-network aggregation and nested queries can significantly affect network traffic. In one experiment aggregation reduces traffic by up to 42% and nested queries reduce loss rates by 30%. Although aggregation has been previously studied in simulation, this paper demonstrates nested queries as another form of in-network processing, and it presents the first evaluation of these approaches over an operational testbed. | [
1044,
2807,
2818
] | Train |
1,622 | 5 | Learning from History for Behavior-Based Mobile Robots in Non-Stationary Conditions . Learning in the mobile robot domain is a very challenging task, especially in nonstationary conditions. The behavior-based approach has proven to be useful in making mobile robots work in real-world situations. Since the behaviors are responsible for managing the interactions between the robots and its environment, observing their use can be exploited to model these interactions. In our approach, the robot is initially given a set of "behavior-producing" modules to choose from, and the algorithm provides a memory-based approach to dynamically adapt the selection of these behaviors according to the history of their use. The approach is validated using a vision- and sonar-based Pioneer I robot in non-stationary conditions, in the context of a multirobot foraging task. Results show the effectiveness of the approach in taking advantage of any regularities experienced in the world, leading to fast and adaptable specialization for the learning robot. Keywords: Multi-robot learning, histor... | [
281,
528,
533,
1762,
1799,
3091
] | Train |
1,623 | 2 | Bringing Information Extraction out of the Labs: the Pinocchio Environment . Pinocchio is an environment for developing Information Extraction applications. New applications and languages can be covered by just writing declarative resources. Information is represented uniformly throughout the architecture: all the modules use the same input structure and the same type of declarative resources. Modules are implemented via the same basic processors and share a common environment for resource development and debugging. The result is an environment easy to use with limited training and skills. 1 INTRODUCTION The exponential increase in the quantity of information held in digital archives has fueled growing interest in techniques for Information Extraction. Given that the vast majority of available information is textual (e.g., web pages, electronic newspapers, agency news), the role of Information Extraction from text (IE) is becoming more and more central. An IE system extracts pieces of information that are salient to the user's needs. The typical output is a... | [
47,
1527
] | Test |
1,624 | 3 | The Persistent Cache: Improving OID Indexing in Temporal Object-Oriented Database Systems In a temporal OODB, an OID index (OIDX) is needed to map from OID to the physical location of the object. In a transaction time temporal OODB, the OIDX should also index the object versions. In this case, the index entries, which we call object descriptors (OD), also include the commit timestamp of the transaction that created the object version. The OIDX in a non-temporal OODB only needs to be updated when an object is created, but in a temporal OODB, the OIDX have to be updated every time an object is updated. We have in a previous study shown that this can be a potential bottleneck, and in this report, we present the Persistent Cache (PCache), a novel approach which reduces the index update and lookup costs in temporal OODBs. In this report, we develop a cost model for the PCache, and use this to show that the use of a PCache can reduce the average access cost to only a fraction of the cost when not using the PCache. Even though the primary context of this report is OID indexing in ... | [
1441
] | Train |
1,625 | 3 | Abduction with Negation as Failure for Active Databases and Agents Recent work has suggested abductive logic programming as a suitable formalism to represent active databases and intelligent agents. In particular, abducibles and integrity constaints in abductive logic programs can be used respectively to represent actions and active/reactive rules. One would expect that, in this approach, abductive proof procedures could provide the engine underlying active database management systems and agents. We analyse existing abductive proof procedures and argue that they are inadequate in handling these applications. The inadequacy is due to the "incorrect" treatment of negative literals in integrity constraints. We propose a new abductive proof procedure and give examples of how this proof procedure can be used to achieve active behaviour in (deductive) databases and proactivity and reactivity in agents. | [
872,
1192,
1325
] | Train |
1,626 | 2 | Eliminators and Classifiers Classification may not be reliable for several reasons: noise in the data, insufficient input information, overlapping distributions and sharp definition of classes. Faced with K possibilities a decision support system may still be useful in such cases if instead of classification elimination of improbable classes is done. Eliminators may be constructed using classifiers assigning new cases to a pool of several classes instead of just one winning class. Elimination may be done with the help of several classifiers using modified error functions. A real life medical example is presented illustrating the usefulness of elimination. | [
135,
1596,
2810
] | Test |
1,627 | 2 | Identifying the Subject of Documents in Digital Libraries Automatically Using Contemporary information databases contain millions of electronic documents. The immense number of documents makes it difficult to conduct efficient searches on the Internet. Several studies have found that associating documents with a subject or list of topics can make them easier to locate online [5] [6] [7]. Effective cataloging of information is performed manually, requiring extensive resources. Consequently, at present most information is not cataloged. This paper will present the findings of a study based on a software tool (TextAnalysis) that automatically identifies the subject of a document. We tested documents in two subject categories: geography and family studies. The present study follows an earlier one that examined the subject categories of industrial management and general management. | [
23,
901,
1105,
2535,
2781
] | Test |
1,628 | 0 | A Collective Robotics Application Based On Emergence And Self-Organization This paper presents a collective robotics application, which consists of making a pool of robots regroup objects that are distributed in their environment. The innovative aspect in our approach rests on a system integrating operationally autonomous robots that make the global task achieved by virtue of emergence and self-organization. 1 INTRODUCTION Our work fits in the framework of Bottom-Up Artificial Intelligence (Bottom-Up AI in short) and more particularly in that of Autonomous Agents. We are concerned with collective phenomena and their issues and more precisely the way to carry out solutions that allow a multi-robot system to achieve global tasks by virtue of emergence and self-organization. Our work is supported by two types of experiments, namely those involving multi-agent simulations and those involving real robots. Our paper precisely presents a collective robotics application, which consists of making a pool of autonomous robots regroup objects that are distributed in thei... | [
845,
2146
] | Test |
1,629 | 5 | Achieving Robust Human-Computer Communication This paper describes a computational approach to robust human-computer interaction. The approach relies on an explicit, declarative representation of the content and structure of the interaction that a computer system builds over the course of the interaction. In this paper, we will show how this representation allows the system to recognize and repair misunderstandings between the human and the computer. We demonstrate the utility of the representations by showing how they facilitate the repair process. 1 Introduction In dialogs between people or between people and machines, understanding is an uncertain process. If the goals or beliefs of two discourse 1 participants differ, one of them might interpret an event in the dialog in a way that she believes is complete and correct, although her interpretation is not the one that the other one had intended. When this happens, we as analysts (or observers) would say that a misunderstanding has occurred. The participants themselves might... | [
774
] | Train |
1,630 | 5 | The CMUnited-97 Small Robot Team Abstract. Robotic soccer is a challenging research domain which involves multiple agents that need to collaborate in an adversarial environment toachieve speci c objectives. In this paper, we describe CMUnited, the team of small robotic agents that we developed to enter the RoboCup-97 competition. We designed and built the robotic agents, devised the appropriate vision algorithm, and developed and implemented algorithms for strategic collaboration between the robots in an uncertain and dynamic environment. The robots can organize themselves in formations, hold speci c roles, and pursue their goals. In game situations, they have demonstrated their collaborative behaviors on multiple occasions. The robots can also switch roles to maximize the overall performance of the team. We present anoverview of the vision processing algorithm which successfully tracks multiple moving objects and predicts trajectories. The paper then focusses on the agent behaviors ranging from low-level individual behaviors to coordinated, strategic team behaviors. CMUnited won the RoboCup-97 small-robot competition at IJCAI-97 in Nagoya, Japan. 1 | [
287,
864,
962,
1573,
2264,
3173
] | Test |
1,631 | 1 | Using Multi-Strategy Learning to Improve Planning Efficiency and Quality | [
1429
] | Train |
1,632 | 5 | Ramification Analysis Using Causal Mapping To operate in the real-world, intelligent agents constantly need to absorb new information, and to consider the ramifications of it. This raises interesting questions for knowledge representation and reasoning. Here we consider ramification analysis in which we wish to determine both the likely outcomes from events occuring and the less likely, but very significant outcomes, from events occuring. To formalize ramification analysis, we introduce the notion of causal maps for modelling "causal relationships" between events. In particular, we consider existential event classes, for example presidential-election, with instances being true, false, or unknown, and directional events classes, for example inflation, with instances being increasing, decreasing or unchanging. Using causal maps, we can propagate new information to determine possible ramifications. These ramifications are also described in terms of events. Whilst causal maps offer a lucid view on ramifications, we also want to su... | [
274,
1443
] | Test |
1,633 | 4 | DAB: Interactive Haptic Painting with 3D Virtual Brushes We present a novel painting system with an intuitive haptic interface, which serves as an expressive vehicle for interactively creating painterly works. We introduce a deformable, 3D brush model, which gives the user natural control of complex brush strokes. The force feedback enhances the sense of realism and provides tactile cues that enable the user to better manipulate the paint brush. We have also developed a bidirectional, two-layer paint model that, combined with a palette interface, enables easy loading of complex blends onto our 3D virtual brushes to generate interesting paint effects on the canvas. The resulting system, DAB, provides the user with an artistic setting, which is conceptually equivalent to a real-world painting environment. Several users have tested DAB and were able to start creating original art work within minutes. | [
1364
] | Validation |
1,634 | 4 | Context Awareness and Mobile Phones : This paper investigates some aspects of how context-awareness can support users of mobile phones, in particular the calling party. The use of mobile and stationary phones is discussed in relation to situational properties of a phone conversation, especially with regards to who might benefit from context-awareness in this context. An initial hypothesis is that mobile phone users communicate context information to each other (verbally) to a much higher degree than do stationary phone users. Mobile phone users could benefit much from context awareness technology, in particular when about to make a call, if they can receive context information regarding the person they are trying to reach prior to establishing the call. We argue that such technology should require low amounts of explicit user interaction, and could lead to less disrupting calls in inappropriate moments, as well as less frustration for the calling party when a call is not answered. Keywords: Computer mediated communicati... | [
2118,
2472
] | Test |
1,635 | 3 | Incremental Maintenance of Materialized OQL Views The importance of materialized views has grown significantly with the advent of data warehousing and OLAP technology. This increases the relevance of solutions to the problem of incrementally maintaining materialized views. So far, most work on this problem has been confined to relational settings. Proposals that apply to object databases have either used non-standard models or fallen short of providing a comprehensive framework. This paper contributes a solution to the incremental view maintenance problem for a large class of views expressed in OQL, the query language of the ODMG standard for object databases. The solution applies to immediate update propagation, and works for any update operation on views de ned over a substantial subset of ODMG types. The approach presented has been fully implemented and preliminary performance results are reported. | [
869,
2575,
2934
] | Train |
1,636 | 1 | Why Unary and Binary Operations in Logic: General Result Motivated by Interval-Valued Logics Traditionally, in logic, only unary and binary operations are used as basic ones -- e.g., "not", "and", "or" -- while the only ternary (and higher order) operations are the operations which come from a combination of unary and binary ones. For the classical logic, with the binary set of truth values f0; 1g, the possibility to express an arbitrary operation in terms of unary and binary ones is well known: it follows, e.g., from the well known possibility to express an arbitrary operation in DNF form. A similar representation result for [0; 1]-based logic was proven in our previous paper. In this paper, we expand this result to finite logics (more general than classical logic) and to multi-D analogues of the fuzzy logic -- both motivated by interval-valued fuzzy logics. 1. | [
1388
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1,637 | 5 | IaDEA: A Development Environment Architecture for Building Generic Intelligent User Interface Agents The need exists in the work force for generic intelligent user interface agents to address the problem of increasing taskload that is overwhelming the human user. Interface agents could help alleviate user taskload by providing abstractions and intelligent assistance in a self-contained software agent that communicates with the user through the existing user interface and also adapts to user needs and behaviors. The benefits of a generic intelligent user interface agent environment is it can be applied to any highly interactive and information intensive software system from freight and parcel management systems to Wall Street financial investment and analysis. We desire to address the two following difficulties with developing interface agents: (1) The extensive number of existing computer systems makes it impractical to build these agents by hand for each system; (2) Any such agent must be compliant with existing user interface standards and business practices (e.g., the United States... | [
1382
] | Train |
1,638 | 3 | Revisiting Structured Storage: A Transactional Record Store An increasing number of applications, such as electronic mail servers, web servers, and personal information managers, handle large amounts of homogeneous data. This data can be effectively represented as records and manipulated through simple operations, e.g., record reading, writing, and searching. Unfortunately, modern storage systems are inappropriate for the needs of these applications. On one side, file systems store only unstructured data (byte strings) with very limited reliability guarantees. On the other side, relational databases store structured data and provide both concurrency control and transactions; but relational databases are often too slow, complex, and difficult to manage for many applications. This paper presents a transactional record store that directly addresses the needs of modern applications. The store combines the simplicity and manageability of the file system interface with a select few features for managing record-oriented data. We describe the principles guiding the design of our transactional record store as well as its design. We also present a prototype implementation and its performance evaluation. 1 | [
2953
] | Train |
1,639 | 4 | An Information Search Cost Perspective for Designing Interfaces for Electronic Commerce This research helps web developers apply knowledge on information search costs to the design of a web site for selling consumer products or services. The goal of the research is to predict how subtle changes in the user interface design influence information search costs. An empirical study compared 1,411 choices subjects made regarding a business to patronize from paper and electronic telephone directories. The choices were contingent upon information search costs imposed by the media. By providing a theoretical basis for predicting differences in information search costs, this research helps designers create more effective web sites for achieving their marketing objectives. 1 An Information Search Cost Perspective for Designing Interfaces for Electronic Commerce INTRODUCTION Now more than ever, the promise of electronic commerce and on-line shopping will depend to a great extent upon the user interface and how people interact with the computer. In particular, success will depend ... | [
1917
] | Test |
1,640 | 2 | Generating Extraction-Based Summaries from Hand-Written Summaries by Aligning Text Spans Human-quality text summarization systems based on sentence extraction are difficult to design because documents can differ along several dimensions, such as length, writing style and lexical usage. The lack of suitable corpora of extraction-based summaries makes it difficult to evaluate and improve existing algorithms. However, there are a large number of hand-written (not extraction-based) summaries available for news-wire stories. This paper discusses our work on generating a corpus of approximately 25,000 extractionbased summaries from hand-written summaries. We discuss how text-span alignment can be applied to this problem and how this problem differs from previous work on aligning parallel texts. In addition, we briefly analyze differences between handwritten and extracted summaries. 1 Introduction Human-quality text summarization systems based on sentence extraction are difficult to design, and even more difficult to evaluate, because documents can differ along several dimension... | [
788,
1152,
1241
] | Train |
1,641 | 2 | Automated Collaborative Filtering Applications for Online Recruitment Services . Online recruitment services suffer from shortcomings due to traditional search techniques. Most users fail to construct queries that provide an adequate and accurate description of their (job) requirements, leading to imprecise search results. We investigate one potential solution that combines implicit profiling methods and automated collaborative filtering (ACF) techniques to build personalised query-less job recommendations. Two ACF strategies are implemented and evaluated in the JobFinder domain. 1 Introduction Online recruitment services have emerged as one of the most successful and popular information services on the Internet, providing job seekers with a comprehensive database of jobs and a dedicated search engine. For example, the award-winning Irish site, JobFinder (www.jobfinder.ie). However, like many similar Internet applications JobFinder suffers from shortcomings, due to its reliance on traditional database technology and the client-pull information access mode... | [
2928
] | Train |
1,642 | 2 | Estimating the Usefulness of Search Engines In this paper, we present a statistical method to estimate the usefulness of a search engine for any given query. The estimates can be used by a metasearch engine to choose local search engines to invoke. For a given query, the usefulness of a search engine in this paper is defined to be a combination of the number of documents in the search engine that are sufficiently similar to the query and the average similarity of these documents. Experimental results indicate that the proposed estimation method is quite accurate. 1 Introduction Many search engines have been created on the Internet to help ordinary users find desired data. Each search engine has a corresponding database that defines the set of documents that can be searched by the search engine. Usually, an index for all documents in the database is created and stored in the search engine to speed up query processing. The amount of data in the Internet is huge (it is believed that by the end of 1997, there were more than 300 mil... | [
263,
488,
583,
587,
976,
982,
1059,
1108,
1134,
1167,
1308,
1804,
1888,
2188,
2771,
2920,
3139
] | Test |
1,643 | 3 | A Framework for Ontology Integration One of the basic problems in the development of techniques for the semantic web is the integration of ontologies. Indeed, the web is constituted by a variety of information sources, each expressed over a certain ontology, and in order to extract information from such sources, their semantic integration and reconciliation in terms of a global ontology is required. In this paper, we address the fundamental problem of how to specify the mapping between the global ontology and the local ontologies. We argue that for capturing such mapping in an appropriate way, the notion of query is a crucial one, since it is very likely that a concept in one ontology corresponds to a view (i.e., a query) over the other ontologies. As a result query processing in ontology integration systems is strongly related to view-based query answering in data integration. 1 | [
1252,
2235,
2594,
2789
] | Test |
1,644 | 1 | Linkage Learning via Probabilistic Modeling in the ECGA The goal of linkage learning, or building block identification, is the creation of a more effective genetic algorithm (GA). This paper explores the relationship between the linkage-learning problem and that of learning probability distributions over multi-variate spaces. Herein, it is argued that these problems are equivalent. Using a simple but effective approach to learning distributions, and by implication linkage, this paper reveals the existence of GA-like algorithms that are potentially orders of magnitude faster and more accurate than the simple GA. I. Introduction Linkage learning in genetic algorithms (GAs) is the identification of building blocks to be conserved under crossover. Theoretical studies have shown that if an effective linkage-learning GA were developed, it would hold significant advantages over the simple GA (2). Therefore, the task of developing such an algorithm has drawn significant attention. Past approaches to developing such an algorithm have focused on ev... | [
917,
1244,
1732
] | Validation |
1,645 | 4 | The Amulet Environment: New Models for Effective User Interface Software Development Abstract—The Amulet user interface development environment makes it easier for programmers to create highly-interactive, graphical user interface software for Unix, Windows and the Macintosh. Amulet uses new models for objects, constraints, animation, input, output, commands, and undo. The object system is a prototype-instance model in which there is no distinction between classes and instances or between methods and data. The constraint system allows any value of any object to be computed by arbitrary code and supports multiple constraint solvers. Animations can be attached to existing objects with a single line of code. Input from the user is handled by “interactor ” objects which support reuse of behavior objects. The output model provides a declarative definition of the graphics and supports automatic refresh. Command objects encapsulate all of the information needed about operations, including support for various ways to undo them. A key feature of the Amulet design is that all graphical objects and behaviors of those objects are explicitly represented at run-time, so the system can provide a number of high-level built-in functions, including automatic display and editing of objects, and external analysis and control of interfaces. Amulet integrates these capabilities in a flexible and effective manner. Index Terms—Toolkits, user interface tools, user interface development environments, user interface management systems (UIMSs). 1 | [
635,
682,
1729,
1968,
2218
] | Train |
1,646 | 3 | XML with Data Values: Typechecking Revisited We investigate the typechecking problem for XML queries: statically verifying that every answer to a query conforms to a given output DTD, for inputs satisfying a given input DTD. This problem had been studied by a subset of the authors in a simplified framework that captured the structure of XML documents but ignored data values. We revisit here the typechecking problem in the more realistic case when data values are present in documents and tested by queries. In this extended framework, typechecking quickly becomes undecidable. However, it remains decidable for large classes of queries and DTDs of practical interest. The main contribution of the present paper is to trace a fairly tight boundary of decidability for typechecking with data values. The complexity of typechecking in the decidable cases is also considered. 1. | [
201,
1318,
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] | Train |
1,647 | 1 | Learning to Extract Keyphrases from Text Many academic journals ask their authors to provide a list of about five to fifteen key words, to appear on the first page of each article. Since these key words are often phrases of two or more words, we prefer to call them keyphrases. There is a surprisingly wide variety of tasks for which keyphrases are useful, as we discuss in this paper. Recent commercial software, such as Microsoft's Word 97 and Verity's Search 97, includes algorithms that automatically extract keyphrases from documents. In this paper, we approach the problem of automatically extracting keyphrases from text as a supervised learning task. We treat a document as a set of phrases, which the learning algorithm must learn to classify as positive or negative examples of keyphrases. Our first set of experiments applies the C4.5 decision tree induction algorithm to this learning task. The second set of experiments applies the GenEx algorithm to the task. We developed the GenEx algorithm specifically for this task. T... | [
1608,
1746
] | Train |
1,648 | 1 | Discovering Association Rules based on Image Content Our focus for data mining in this paper is concerned with knowledge discovery in image databases. We present a data mining algorithm to find association rules in 2-dimensional color images. The algorithm has four major steps: feature extraction, object identification, auxiliary image creation and object mining. Our emphasis is on data mining of image content without the use of auxiliary domain knowledge. The purpose of our experiments is to explore the feasibility of this approach. A synthetic image set containing geometric shapes was generated to test our initial algorithm implementation. Our experimental results show that there is promise in image mining based on content. We compare these results against the rules obtained from manually identifying the shapes. We analyze the reasons for discrepancies. We also suggest directions for future work. 1. Introduction Discovering knowledge from data stored in typical alphanumeric databases, such as relational databases, has been the focal p... | [
192,
662
] | Train |
1,649 | 4 | Routing Through the Mist: Privacy Preserving Communication in Ubiquitous Computing Environments Ubiquitous computing is poised to revolutionize the way we compute and interact with each other. However, unless privacy concerns are taken into account early in the design process, we will end up creating a very effective distributed surveillance system, which would be a dream come true for electronic stalkers and "big brothers. " We present a protocol, which preserves the privacy of users and keeps their communication anonymous. In effect, we create a "mist" that conceals users from the system and other users. Yet, users will still be able to enjoy seamless interaction with services and other entities that wander within the ubiquitous computing environment. Keywords Ubiquitous computing, privacy, Mist Routers, anonymous communication, authentication, security 1. | [
837
] | Test |
1,650 | 3 | StorHouse/Relational Manager (RM) - Active Storage Hierarchy Database System and Applications This paper describes how database systems can use and exploit a cost-effective active storage hierarchy. By active storage hierarchy we mean a database system that uses all storage media (i.e. optical, tape, and disk) to store and retrieve data and not just disk. We describe and emphasize the active part, whereby all storage types are used to store raw data that is converted to strategic business information. We describe an evolution to the Data Warehouse concept, called Atomic Data Store, whereby atomic data is stored in the database system. Atomic data is defined as storing all the historic data values and executing queries against the historic queries. We also describe a Data Warehouse information collection, flow and central data store Hub-and-Spoke architecture, used to feed data into Data Marts. We also describe a commercial product; StorHouse/Relational Manager (RM). RM is a commercial relational database system that executes SQL queries directly against data stored on the storage hierarchy (i.e. tape, optical, disk). We conclude with a brief overview of a real world AT&T Call Detail Warehouse (CDW) case study. | [
3068
] | Train |
1,651 | 4 | Eyes in the Interface Computer vision has a significant role to play in the human-computer interaction (HCI) devices of the future. All computer input devices serve one essential purpose. They transduce some motion or energy from a human agent into machine useable signals. One may therefore think of input devices as the `perceptual organs' by which computers sense the intents of their human users. We outline the role computer vision will play, highlight the impediments to the development of vision-based interfaces, and propose an approach for overcoming these impediments. Prospective vision research areas for HCI include human face recognition, facial expression interpretation, lip reading, head orientation detection, eye gaze tracking, three-dimensional finger pointing, hand tracking, hand gesture interpretation, and body pose tracking. For vision-based interfaces to make any impact, we will have to embark on an expansive approach which begins with the study of the interaction modality we seek to implement... | [
1454
] | Validation |
1,652 | 1 | Neurobotics Lab Research: Learning, Vision and Sonar Recognition with Mobile Robots This article provides an overview of research projects undertaken in the Neurobotics Laboratory at Boston University. We focus on applications of neural networks and other biomimetic techniques in sensory processing, navigation, and other tasks using mobile robots. These applications share some central themes: the inclusion of minimal assumptions about the robots and the environment; cross-validation of modules on a variety of robotics platforms and environments; and real-time operation using real robots. Keywords: Mobile robots, looming, mobile robots, robot learning, Neural networks, ARTMAP, sensor fusion 1 Introduction The Neurobotics Laboratory was founded in 1996 with the goal of applying neural networks and other biomimetic techniques to the control and guidance of wheeled mobile robot. Research in the lab covers various problems in the general area of autonomous mobile robotics, with an emphasis on navigation and control using biomimetic algorithms that operate in real-time wi... | [
1708
] | Validation |
1,653 | 4 | Spatially aware local communication in the RAUM system In this paper, we propose a new paradigm for local communication between devices in Ubiquitous Computing environments, assuming a multitude of computerized everyday appliances communicating with each other to solve tasks. This paradigm is based on the concept that the location of devices is central for the communication in such a scenario. Devices define their communication scope by spatial criteria. In our paradigm no explicit addressing or identification of communication partners is used. In comparison to traditional communication methods the approach eases routing and discovery problems and can be deployed in a highly dynamic environment without centralized services. We use the term local communication as inter-device communication in a physically restricted local area. This is well distinguish from the terms telecommunication as communication over distance where location information is explicitly hidden. The communication model (RAUM) introduced is based on the observ... | [
1035,
1156,
3087
] | Validation |
1,654 | 4 | Affine Object Representations for Calibration-Free Augmented Reality We describe the design and implementation of a videobased augmented reality system capable of overlaying threedimensional graphical objects on live video of dynamic environments. The key feature of the system is that it is completely uncalibrated: it does not use any metric information about the calibration parameters of the camera or the 3D locations and dimensions of the environment’s objects. The only requirement is the ability to track across frames at least four feature points that are specified by the user at system initialization time and whose world coordinates are unknown. Our approach is based on the following observation: Given a set of four or more non-coplanar 3D points, the projection of all points in the set can be computed as a linear combination of the projections of just four of the points. We exploit this observation by (1) tracking lines and fiducial points at frame rate, and (2) representing virtual objects in a non-Euclidean, affine frame of reference that allows their projection to be computed as a linear combination of the projection of the fiducial points. 1. | [
1266,
1713
] | Train |
1,655 | 3 | Point- Versus Interval-based Temporal Data Models The association of timestamps with various data items such as tuples or attribute values is fundamental to the management of time-varying information. Using intervals in timestamps, as do most data models, leaves a data model with a variety of choices for giving a meaning to timestamps. Specifically, some such data models claim to be point-based while other data models claim to be interval-based. The meaning chosen for timestamps is important---it has a pervasive effect on most aspects of a data model, including database design, a variety of query language properties, and query processing techniques, e.g., the availability of query optimization opportunities. This paper precisely defines the notions of point-based and interval-based temporal data models, thus providing a new, formal basis for characterizing temporal data models and obtaining new insights into the properties of their query languages. Queries in point-based models treat snapshot equivalent argument relations identically.... | [
10
] | Validation |
1,656 | 1 | The Genetic Algorithm as a Discovery Engine: Strange Circuits and New Principles This paper examines the idea of a genetic or evolutionary algorithm being an inspirational or discovery engine. This is illustrated in the particular context of designing electronic circuits. We argue that by connecting pieces of logic together and testing them to see if they carry out the desired function it may be possible to discover new principles of design, and new algebraic techniques. This is illustrated in the design of binary circuits, particularly arithmetic functions, where we demonstrate that by evolving a hierarchical series of examples, it becomes possible to re-discover the well known ripple-carry principle for building adder circuits of any size. We also examine the much harder case of multiplication. We show also that extending the work into the field of multiple-valued logic, the genetic algorithm is able to produce fully working circuits that lie outside conventional algebra. In addition we look at the issue of principle extraction from evolved data. 1 Introduction ... | [
3171
] | Train |
1,657 | 4 | Mindless Visualisations The wonder and, unfortunately, to the detriment of visualisation for the representation and comprehension of complex data sets is that to be most successful requires that they are tailored to suit the task and underlying data. Such a restriction enables visualisations to be well designed for the tasks to which they are known to be applied to, and also to accommodate the style and range of data to be expected as normal. The problem with this repeated redesign of visualisations is that the interface is often neglected, and can even be solely dependent on the implementing technology used for the visualisation. It is important to add such issues as the interface to visualisation considerations, and to provide reusable concepts that will integrate with a range of metaphors and displays. This position paper examines the issues surrounding such visualisation interfaces and presents a discussion of those issues. 1. | [] | Train |
1,658 | 0 | Contextual Deontic Logic: Normative Agents, Violations and Independence this paper we discuss when and how to use deontic logic in multi agent systems | [
716,
1291,
3030,
3177
] | Validation |
1,659 | 4 | Preliminary Investigation of Wearable Computers for Task Guidance in Aircraft Inspection This paper describes a preliminary investigation of how the capabilities of wearable computers may be used to provide task guidance in mobile environments. Specifically, this study examined how the capabilities of wearable computers may be used to aid a user in an inspection task, using as a case study the procedural task of preflight inspection of a general aviation aircraft. Two different configurations of a computer-based, voiceactivated task guidance system and the current method of preflight inspection were compared and evaluated. Initial results demonstrate an over reliance on the computer by the pilots and indicate the importance of the user interface design to the performance of the inspectors. The paper concludes with recommendations on promising directions of research. Keywords task guidance, procedural tasks, aircraft inspection, computerized procedures, decision aiding, wearable computers 1. Introduction Wearable computers combine portable, voiceactivated, wireless-netw... | [
1427,
2754
] | Validation |
1,660 | 3 | Temporal Aspects of Semistructured Data In many applications, information about the history of data and their dynamic aspects are just as important as static information. During the last years the increasing amount of information accessible through the Web has presented new challenges to academic and industrial research on database. In this context, data are either structured, when coming from relational or object-oriented databases, or partially or completely unstructured, when they consist of simple collections of text or image files. In the context of semistructured data, model and query languages must be extended in order to consider dynamic aspects. We present a model based on labeled graphs for representing changes in semistructured data and a SQL-like query language for querying it. | [
731,
877,
2632
] | Test |
1,661 | 3 | Scalable Algorithms for Large Temporal Aggregation The ability to model time-varying natures is essential to many database applications such as data warehousing and mining. However, the temporal aspects provide many unique characteristics and challenges for query processing and optimization. Among the challenges is computing temporal aggregates, which is complicated by having to compute temporal grouping. In this paper, we introduce a variety of temporal aggregation algorithms that overcome major drawbacks of previous work. First, for small-scale aggregations, both the worst-case and average-case processing time have been improved significantly. Second, for large-scale aggregations, the proposed algorithms can deal with a database that is substantially larger than the size of available memory. | [
456,
853,
1894
] | Train |
1,662 | 0 | Intention Reconsideration Reconsidered Abstract. In this paper, we consider the issue of designing agents that successfully balance the amount of time spent in reconsidering their intentions against the amount of time spent acting to achieve them. Following a brief review of the various ways in which this problem has previously been analysed, we motivate and introduce a simple formal model of agents, which is closely related to the well-known belief-desire-intention model. In this model, an agent is explicitly equipped with mechanisms for deliberation and action selection, as well as a meta-level control function, which allows the agent to choose between deliberation and action. Using the formal model, we define what it means for an agent to be optimal with respect to a task environment, and explore how various properties of an agent’s task environment can impose certain requirements on its deliberation and meta-level control components. We then show how the model can capture a number of interesting practical reasoning scenarios, and illustrate how our notion of meta-level control can easily be extended to encompass higherorder meta-level reasoning. We conclude with a discussion and pointers to future work. 1 | [
2063,
2400,
2813,
3128
] | Test |
1,663 | 5 | What can Knowledge Representation do for Semi-Structured Data? The problem of modeling semi-structured data is important in many application areas such as multimedia data management, biological databases, digital libraries, and data integration. Graph schemas (Buneman et al. 1997) have been proposed recently as a simple and elegant formalism for representing semistructured data. In this model, schemas are represented as graphs whose edges are labeled with unary formulae of a theory, and the notions of conformance of a database to a schema and of subsumption between two schemas are defined in terms of a simulation relation. Several authors have stressed the need of extending graph schemas with various types of constraints, such as edge existence and constraints on the number of outgoing edges. In this paper we analyze the appropriateness of various knowledge representation formalisms for representing and reasoning about graph schemas extended with constraints. We argue that neither First Order Logic, nor Logic Programming nor Frame-based languages ... | [
242,
1787,
3024
] | Train |
1,664 | 0 | Moral Sentiments in Multi-Agent Systems We present a simulation of a society of agents where some of them have "moral sentiments" towards the agents that belong to the same social group, using the Iterated Prisoner's Dilemma as a metaphor for the social interactions. Besides the well-understood phenomenon of short-sighted, self-interested agents performing well in the short-term but ruining their chances of such performance in the long run in a world of reciprocators, the results suggest that, where some agents are more generous than that, these agents have a positive impact on the social group to which they belong, without compromising too much their individual performance (i.e., the group performance improves). The inspiration for this project comes from a discussion on Moral Sentiments by M.Ridley. We describe various simulations where conditions and parameters over determined dimensions were arranged to account for different types and compositions of societies. Further, we indicate several lessons that arise from the analysis of the results and comparison of the different experiments. We also relate this work to our previous anthropological approach to the adaptation of migrant agents, and argue that allowing agents to possess suitably-chosen emotions can have a decisive impact on Multi-Agent Systems. This implies that some common notions of agent autonomy (and related concepts) should be reexamined. | [
429
] | Train |
1,665 | 0 | Using Process Algebras to Formally Specify Mobile Agent Data Integrity Properties: a Case Study This paper shows how cryptographic protocols for mobile agent data integrity properties can be formally specified by using spi calculus, an extension of # calculus with cryptographic properties. In particular, by means of a case study, it is shown how a specification technique initially conceived only for classical cryptographic protocols can be used in the context of mobile agents as well. Our case study includes the spi calculus specification of a sample mobile agent data integrity protocol and of its security property. | [
2260
] | Train |
1,666 | 4 | Interactive Maps for a Digital Video Library The Informedia Digital Video Library contains over 1200 hours of video. Through automatic processing, descriptors are derived for the video to improve library access. A new extension to the video processing is the extraction of geographic references from these descriptors. The operational library interface shows the geographic entities addressed in a given story, highlighting the regions discussed at any point in the video through a map display synchronized with the video playback. The map can also be used as a query mechanism, allowing users to search the terabyte library for stories taking place in a selected area of interest. 1. Introduction The Informedia Project at Carnegie Mellon University investigates the utility of speech recognition, image processing, and natural language processing techniques for improving search and discovery in the video medium. Since 1994, the project has been digitizing, in MPEG-1 format, news video from CNN as well as documentary/educational video fro... | [
17,
2097
] | Train |
1,667 | 3 | Incremental Maintenance for Materialized Views over Semistructured Data Semistructured data is not strictly typed like relational or object-oriented data and may be irregular or incomplete. It often arises in practice, e.g., when heterogeneous data sources are integrated or data is taken from the World Wide Web. Views over semistructured data can be used to filter the data and to restructure (or provide structure to) it. To achieve fast query response time, these views are often materialized. This paper studies incremental maintenance techniques for materialized views over semistructured data. We use the graph-based data model OEM and the query language Lorel, developed at Stanford, as the framework for our work. We propose a new algorithm that produces a set of queries that compute the changes to the view based upon a change to the source. We develop an analytic cost model and compare the cost of executing our incremental maintenance algorithm to that of recomputing the view. We show that for nearly all types of database updates, it is more efficient to a... | [
754,
886,
965,
1576,
1771,
2120,
2981,
3151
] | Train |
1,668 | 3 | Planning in Interplanetary Space: Theory and Practice On May 17th 1999, NASA activated for the first time an AI-based planner/scheduler running on the flight processor of a spacecraft. This was part of the Remote Agent Experiment (RAX), a demonstration of closedloop planning and execution, and model-based state inference and failure recovery. This paper describes the RAX Planner/Scheduler (RAX-PS), both in terms of the underlying planning framework and in terms of the fielded planner. RAX-PS plans are networks of constraints, built incrementally by consulting a model of the dynamics of the spacecraft. The RAX-PS planning procedure is formally well defined and can be proved to be complete. RAX-PS generates plans that are temporally flexible, allowing the execution system to adjust to actual plan execution conditions without breaking the plan. The practical aspect, developing a mission critical application, required paying attention to important engineering issues such as the design of methods for programmable search contr... | [
2122
] | Train |
1,669 | 3 | From Binary Temporal Relations to Non-Binary Ones and Back In this paper a new approach towards temporal reasoning is presented that scales up from the temporal relations commonly used in Allen's qualitative interval calculus and in quantitative temporal constraint satisfaction problems to include interval relations with distances, temporal rules and other non-binary relations into the reasoning scheme. For this purpose, we generalize well-known methods for constraint propagation, determination of consistency and computation of the minimal network from simpler schemes that only allow for binary relations. Thereby, we nd that levels of granularity play a major role for applying these techniques in our more expressive framework. Indeed, the technical preliminaries we provide are especially apt to investigate the switching between dierent granularities of representation, hence illucitating and exploiting the tradeo between expressiveness and eciency of temporal reasoning schemes on the one side and between expressiveness and understandability ... | [
2481
] | Train |
1,670 | 3 | Answering Queries by Semantic Caches There has been growing interest in semantic query caches to aid in query evaluation. Semantic caches are simply the results of previously asked queries, or selected relational information chosen by an evaluation strategy, that have been cached locally. For complex environments such as distributed, heterogeneous databases and data warehousing, the use of semantic caches promises to help optimize query evaluation, increase turnaround for users, and reduce network load and other resource usage. We present a general logical framework for semantic caches. We consider the use of all relational operations across the caches for answering queries, and we consider the various ways to answer, and to partially answer, a query by cache. We address when answers are in cache, when answers in cache can be recovered, and the notions of semantic overlaps, semantic independence, and semantic query remainder. While there has been much work relevant to the use of semantic caches, no one has addressed in conjunction the issues pertinent to the effective use of semantic caches to evaluate queries. In some cases, this is due to overly simplified assumptions, and in other cases to the lack of a formal framework. We attempt to establish some of that framework here. Within that framework, we illustrate the issues involved in using semantic caches for query evaluation. We show various applications for semantic caches, and relate the work to relevant areas. 1 | [
2385,
2554
] | Train |
1,671 | 4 | Phidgets: Easy Development of Physical Interfaces through Physical Widgets Physical widgets or phidgets are to physical user interfaces what widgets are to graphical user interfaces. Similar to widgets, phidgets abstract and package input and output devices: they hide implementation and construction details, they expose functionality through a well-defined API, and they have an (optional) on-screen interactive interface for displaying and controlling device state. Unlike widgets, phidgets also require: a connection manager to track how devices appear on-line; a way to link a software phidget with its physical counterpart; and a simulation mode to allow the programmer to develop, debug and test a physical interface even when no physical device is present. Our evaluation shows that everyday programmers using phidgets can rapidly develop physical interfaces. | [
1082,
2574
] | Train |
1,672 | 3 | Using LDAP Directory Caches this paper, we consider the problem of reusing cached LDAP directory entries for answering (declarative) LDAP queries. We develop a suite of query transformations that capture the semantics of LDAP queries, and design a sound and complete algorithm for determining whether a conjunctive LDAP query is cacheanswerable using positive query templates. We demonstrate the practicality of our algorithm for real applications with a preliminary performance evaluation, based on sample queries from a directory enabled application at AT&T Labs. Cache-answerability is related to the problem of finding complete rewritings of a query using views (see, e.g., [8]). A key conceptual difference arises due to the fact that we do not seek a rewriting of the original query in terms of the (views in the) semantic cache description, but want to evaluate the original query against the cached directory instance. Further, the differences of the LDAP data model and query language make the previous results inapplicable; for details, see Section 2. | [
655,
1787,
2037,
3024
] | Train |
1,673 | 1 | Mixtures of Probabilistic Principal Component Analysers Principal component analysis (PCA) is one of the most popular techniques for processing, compressing and visualising data, although its effectiveness is limited by its global linearity. While nonlinear variants of PCA have been proposed, an alternative paradigm is to capture data complexity by a combination of local linear PCA projections. However, conventional PCA does not correspond to a probability density, and so there is no unique way to combine PCA models. Previous attempts to formulate mixture models for PCA have therefore to some extent been ad hoc. In this paper, PCA is formulated within a maximum-likelihood framework, based on a specific form of Gaussian latent variable model. This leads to a well-defined mixture model for probabilistic principal component analysers, whose parameters can be determined using an EM algorithm. We discuss the advantages of this model in the context of clustering, density modelling and local dimensionality reduction, and we demonstrate its applicatio... | [
700,
1403
] | Train |
1,674 | 3 | Development of a Computer Aided Geographic Database Design System This paper presents a prototype being developed at IC-UNICAMP to help environmental planners specify their application databases. The ultimate goal of the system presented is to reduce the impedance mismatch between the end-user's view of the geographic reality and its implementation in Geographic Information Systems (gis). The prototype offers users the possibility of specifying their application databases using concepts closer to their view of the world, by means of an object oriented geographic data model. This specification is mapped by the system to an intermediate object oriented schema, which can then be transformed into different underlying target geographic DBMS. The prototype was implemented using C and O2C on the O2 object oriented DBMS. 1 Introduction A Geographic Information System -- gis, for short -- is a software that performs data management and retrieval operations for georeferenced data. The term refers to data about geographic phenomena associated with its location... | [
2508
] | Train |
1,675 | 1 | Toward Learning Visual Discrimination Strategies Humans learn strategies for visual discrimination through interaction with their environment. Discrimination skills are refined as demanded by the task at hand, and are not a priori determined by any particular feature set. Tasks are typically incompletely specified and evolve continually. This work presents a general framework for learning visual discrimination that addresses some of these characteristics. It is based on an infinite combinatorial feature space consisting of primitive features such as oriented edgels and texture signatures, and compositions thereof. Features are progressively sampled from this space in a simple-to-complex manner. A simple recognition procedure queries learned features one by one and rules out candidate object classes that do not sufficiently exhibit the queried feature. Training images are presented sequentially to the learning system, which incrementally discovers features for recognition. Experimental results on two databases of geometric objects ill... | [
43,
2162,
2812
] | Train |
1,676 | 0 | Toward Learning Based Web Query Processing In this paper, we describe a novel Web query processing approach with learning capabilities. Under this approach, user queries are in the form of keywords and search engines are employed to find URLs of Web sites that might contain the required information. The first few URLs are presented to the user for browsing. Meanwhile, the query processor learns both the information required by the user and the way that the user navigates through hyperlinks to locate such information. With the learned knowledge, it processes the rest URLs and produces precise query results in the form of segments of Web pages without user involvement. The preliminary experimental results indicate that the approach can process a range of Web queries with satisfactory performance. The architecture of such a query processor, techniques of modeling HTML pages, and knowledge for query processing are discussed. Experiments on the effectiveness of the approach, the required knowledge, and the training strategies are presented. | [
759,
1420,
1547,
1782,
2503,
2918
] | Validation |
1,677 | 2 | A Mediation Infrastructure for Digital Library Services Digital library mediators allow interoperation between diverse information services. In this paper we describe a flexible and dynamic mediator infrastructure that allows mediators to be composed from a set of modules ("blades"). Each module implements a particular mediation function, such as protocol translation, query translation, or result merging. All the information used by the mediator, including the mediator logic itself, is represented by an RDF graph. We illustrate our approach using a mediation scenario involving a Dienst and a Z39.50 server, and we discuss the potential advantages and weaknesses of our framework. KEYWORDS: mediator, wrapper, interoperability, component design 1 INTRODUCTION Heterogeneity is one of the main challenges faced by digital libraries. Too often documents are stored in different formats, collections are searched with disparate query languages, search services are accessed with incompatibleprotocols, intellectual property protection and access sche... | [
663,
1819,
1852,
2154
] | Validation |
1,678 | 1 | Rough Fuzzy MLP: Modular Evolution, Rule Generation and Evaluation A methodology is described for evolving a Rough-fuzzy multi layer perceptron with modular concept using a genetic algorithm to obtain a structured network suitable for both classification and rule extraction. The modular concept, based on "divide and conquer" strategy, provides accelerated training and a compact network suitable for generating a minimum number of rules with high certainty values. The concept of variable mutation operator is introduced for preserving the localized structure of the constituting knowledge based subnetworks, while they are integrated and evolved. Rough set dependency rules are generated directly from the real valued attribute table containing fuzzy membership values. Two new indices viz., `certainty' and `confusion' in a decision are defined for evaluating quantitatively the quality of rules. The effectiveness of the model and the rule extraction algorithm is extensively demonstrated through experiments alongwith comparisons. | [
721,
921
] | Train |
1,679 | 1 | Fusion of Perceptual Cues for Robust Tracking of. . . The paradigm of perceptual fusion provides robust solutions to computer vision problems. By combining the outputs of multiple vision modules, the assumptions and constraints of each module are factored out to result in a more robust system overall. The integration of dierent modules can be regarded as a form of data fusion. To this end, we propose a framework for fusing dierent information sources through estimation of covariance from observations. The framework is demonstrated in a face and 3D pose tracking system that fuses similarity-to-prototypes measures and skin colour to track head pose and face position. The use of data fusion through covariance introduces constraints that allow the tracker to robustly estimate head pose and track face position simultaneously. Key words: data fusion, pose estimation, similarity representation, face recognition 1 Introduction The approach we have taken to computer vision, referred to as perceptual fusion, involves the integration of multip... | [
1924
] | Train |
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