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Knowledge and Data Engineering, IEEE Transactions on

Issue 3 • Date May-June 2001

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Displaying Results 1 - 16 of 16
  • Guest editors' introduction: special section on semantic issues of multimedia systems

    Page(s): 335 - 336
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    Freely Available from IEEE
  • Editorial: introducing the new AEs

    Page(s): 393 - 394
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    Freely Available from IEEE
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  • Debiasing training data for inductive expert system construction

    Page(s): 497 - 512
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1268 KB) |  | HTML iconHTML  

    We study the presence of economic bias in the training data used to develop inductive expert systems. Such bias arises when an expert considers economic factors in decision making. We find that the presence of economic bias is particularly harmful when there is an economic misalignment between the expert and the user of the induced expert system. Such misalignment is referred to as differential bias. The most significant contribution of this study is a training data debiasing procedure that uses a genetic algorithm to reconstruct training data that is relatively free of economic bias. We conduct a series of simulation experiments that show: the economic performance of accuracy and value seeking algorithms is statistically the same when the training data has economic bias; both accuracy and value seeking algorithms suffer in the presence of differential bias; the proposed debiasing procedure significantly combats differential bias; and the debiasing procedure is quite robust with respect to estimation errors in its input parameters View full abstract»

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  • Redundancy detection in semistructured case bases

    Page(s): 513 - 518
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB) |  | HTML iconHTML  

    With the dramatic proliferation of case-based reasoning systems in commercial applications, many case bases are now becoming legacy systems. They represent a significant portion of an organization's assets, but they are large and difficult to maintain. One of the contributing factors is that these case bases are often large and yet unstructured or semistructured; they are represented in natural language text. Adding to the complexity is the fact that the case bases are often authored and updated by different people from a variety of knowledge sources, making it highly likely for a case base to contain redundant and inconsistent knowledge. We present methods and a system for maintaining large and semistructured case bases. We focus on a difficult problem in case base maintenance: redundancy detection. This problem is particularly pervasive when one deals with a semistructured case base. We discuss an information retrieval-based algorithm and an implemented system for solving this problem. As the ability to contain the knowledge acquisition problem is of paramount importance, our method allows one to express relevant domain expertise for detecting redundancy naturally and effortlessly. Empirical evaluations of the system demonstrate the effectiveness of the methods in several large domains View full abstract»

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  • A new uncertainty measure for belief networks with applications to optimal evidential inferencing

    Page(s): 416 - 425
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    We are concerned with the problem of measuring the uncertainty in a broad class of belief networks, as encountered in evidential reasoning applications. In our discussion, we give an explicit account of the networks concerned, and call them the Dempster-Shafer (D-S) belief networks. We examine the essence and the requirement of such an uncertainty measure based on well-defined discrete event dynamical systems concepts. Furthermore, we extend the notion of entropy for the D-S belief networks in order to obtain an improved optimal dynamical observer. The significance and generality of the proposed dynamical observer of measuring uncertainty for the D-S belief networks lie in that it can serve as a performance estimator as well as a feedback for improving both the efficiency and the quality of the D-S belief network-based evidential inferencing. We demonstrate, with Monte Carlo simulation, the implementation and the effectiveness of the proposed dynamical observer in solving the problem of evidential inferencing with optimal evidence node selection View full abstract»

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  • Query languages for sequence databases: termination and complexity

    Page(s): 519 - 525
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB) |  | HTML iconHTML  

    This paper develops a query language for sequence databases, such as genome databases and text databases. Unlike relational data, queries over sequential data can easily produce infinite answer sets since the universe of sequences is infinite, even for a finite alphabet. The challenge is to develop query languages that are both highly expressive and finite. This paper develops such a language as a subset of a logic for string databases called Sequence Datalog. The main idea is to use safe recursion to control and limit unsafe recursion. The main results are the definition of a finite form of recursion, called domain-bounded recursion, and a characterization of its complexity and expressive power. Although finite, the resulting class of programs is highly expressive since its data complexity is complete for the elementary functions View full abstract»

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  • ZYX-a multimedia document model for reuse and adaptation of multimedia content

    Page(s): 361 - 382
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    Advanced multimedia applications require adequate support for the modeling of multimedia content by multimedia document models. More and more this support calls for not only the adequate modeling of the temporal and spatial course of a multimedia presentation and its interactions, but also for the partial reuse of multimedia documents and adaptation to a given user context. However, our thorough investigation of existing standards for multimedia document models such as HTML, MHEG, SMIL, and HyTime leads to us the conclusion that these standard models do not provide sufficient modeling support for reuse and adaptation. Therefore, we propose a new approach for the modeling of adaptable and reusable multimedia content, the ZYX model. The model offers primitives that provide-beyond the more or less common primitives for temporal, spatial, and interaction modeling-a variform support for reuse of structure and layout of document fragments and for the adaptation of the content and its presentation to the user context. We present the model in detail and illustrate the application and effectiveness of these concepts by samples taken from our Cardio-OP application in the domain of cardiac surgery. With the ZYX model, we developed a comprehensive means for advanced multimedia content creation: support for template-driven authoring of multimedia content and support for flexible, dynamic composition of multimedia documents customized to the user's local context and needs. The approach significantly impacts and supports the authoring process in terms of methodology and economic aspects View full abstract»

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  • Trends in databases: reasoning and mining

    Page(s): 426 - 438
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    We propose a temporal dependency, called trend dependency (TD), which captures a significant family of data evolution regularities. An example of such regularity is “Salaries of employees generally do not decrease.” TDs compare attributes over time using operators of {<,=,>,⩽,⩾,≠}. We define a satisfiability problem that is the dual of the logical implication problem for TDs and we investigate the computational complexity of both problems. As TDs allow expressing meaningful trends, “mining” them from existing databases is interesting. For the purpose of TD mining, TD satisfaction is characterized by support and confidence measures. We study the problem TDMINE: given a temporal database, mine the TDs that conform to a given template and whose support and confidence exceed certain threshold values. The complexity of TDMINE is studied, as well as algorithms to solve the problem View full abstract»

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  • Data semantics for improving retrieval performance of digital news video systems

    Page(s): 352 - 360
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    We propose a novel four-step hybrid approach for retrieval and composition of video newscasts based on information contained in different metadata sets. In the first step, we use conventional retrieval techniques to isolate video segments from the data universe using segment metadata. In the second step, retrieved segments are clustered into potential news items using a dynamic technique sensitive to the information contained in the segments. In the third step, we apply a transitive search technique to increase the recall of the retrieval system. In the final step, we increase recall performance by identifying segments possessing creation-time relationships. A quantitative analysis of the performance of the process on a newscast composition shows an increase in recall by 59 percent over the conventional keyword-based search technique used in the first step View full abstract»

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  • A survey of languages for specifying dynamics: a knowledge engineering perspective

    Page(s): 462 - 496
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (864 KB) |  | HTML iconHTML  

    A number of formal specification languages for knowledge-based systems has been developed. Characteristics for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide the means to specify a complex and large amount of knowledge and they have to provide the means to specify the dynamic reasoning behavior of a knowledge-based system. We focus on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behavior in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modeling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic) and the generic specification framework of abstract state machines View full abstract»

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  • Fuzzy logic techniques in multimedia database querying: a preliminary investigation of the potentials

    Page(s): 383 - 392
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    Fuzzy logic is known for providing a convenient tool for interfacing linguistic categories with numerical data and for expressing user's preference in a gradual and qualitative way. Fuzzy set methods have been already applied to the representation of flexible queries and to the modeling of uncertain pieces of information in databases systems, as well as in information retrieval. This methodology seems to be even more promising in multimedia databases which have a complex structure and from which documents have to be retrieved and selected not only from their contents, but also from “the idea” the user has of their appearance, through queries specified in terms of user's criteria. This paper provides a preliminary investigation of the potential applications of fuzzy logic in multimedia databases. The problem of comparing semistructured documents is first discussed. Querying issues are then more particularly emphasized. We distinguish two types of request, namely, those which can be handled within some extended version of an SQL-like language and those for which one has to elicit user's preference through examples View full abstract»

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  • Emergent semantics through interaction in image databases

    Page(s): 337 - 351
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    In this paper, we briefly discuss some aspects of image semantics and the role that it plays for the design of image databases. We argue that images don't have an intrinsic meaning, but that they are endowed with a meaning by placing them in the context of other images and by the user interaction. From this observation, we conclude that, in an image, database users should be allowed to manipulate not only the individual images, but also the relation between them. We present an interface model based on the manipulation of configurations of images View full abstract»

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  • Automata for the assessment of knowledge

    Page(s): 451 - 461
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    The results of this paper can be applied to construct efficient algorithms for the adaptive assessment of the students' knowledge. The problem of knowledge assessment is a special case of the problem of assessing the state of a system. These results are obtained suggesting a new assessment algorithm whose formal equivalence to previously suggested assessment algorithms is proven. A simulation study illustrates the vast improvements of efficiency with the new algorithm View full abstract»

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  • Constructing the dependency structure of a multiagent probabilistic network

    Page(s): 395 - 415
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    A probabilistic network consists of a dependency structure and corresponding probability tables. The dependency structure is a graphical representation of the conditional independencies that are known to hold in the problem domain. We propose an automated process for constructing the combined dependency structure of a multiagent probabilistic network. Each domain expert supplies any known conditional independency information and not necessarily an explicit dependency structure. Our method determines a succinct representation of all the supplied independency information called a minimal cover. This process involves detecting all inconsistent information and removing all redundant information. A unique dependency structure of the multiagent probabilistic network can be constructed directly from this minimal cover. The main result is that the constructed dependency structure is a perfect-map of the minimal cover. That is, every probabilistic conditional independency logically implied by the minimal cover can be inferred from the dependency structure and every probabilistic conditional independency inferred from the dependency structure is logically implied by the minimal cover View full abstract»

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  • Global scheduling for flexible transactions in heterogeneous distributed database systems

    Page(s): 439 - 450
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    A heterogeneous distributed database environment integrates a set of autonomous database systems to provide global database functions. A flexible transaction approach has been proposed for the heterogeneous distributed database environments. In such an environment, flexible transactions can increase the failure resilience of global transactions by allowing alternate (but in some sense equivalent) executions to be attempted when a local database system fails or some subtransactions of the global transaction abort. We study the impact of compensation, retry, and switching to alternative executions on global concurrency control for the execution of flexible transactions. We propose a new concurrency control criterion for the execution of flexible and local transactions, termed F-serializability, in the error-prone heterogeneous distributed database environments. We then present a scheduling protocol that ensures F-serializability on global schedules. We also demonstrate that this scheduler avoids unnecessary aborts and compensation View full abstract»

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Aims & Scope

IEEE Transactions on Knowledge and Data Engineering (TKDE) informs researchers, developers, managers, strategic planners, users, and others interested in state-of-the-art and state-of-the-practice activities in the knowledge and data engineering area.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Jian Pei
Simon Fraser University