Catálogo de publicaciones - revistas

<jats:p>This article surveys probablistic approaches to modeling information retrieval. The basic concepts of probabilistic approaches to information retrieval are outlined and the principles and assumptions upon which the approaches are based are presented. The various models proposed in the development of IR are described, classified, and compared using a common formalism. New approaches that constitute the basis of future research are described.</jats:p>

<jats:p> Fault tolerance in distributed computing is a wide area with a significant body of literature that is vastly diverse in methodology and terminology. This paper aims at structuring the area and thus guiding readers into this interesting field. We use a formal approach to define important terms like <jats:italic>fault, fault tolerance</jats:italic> , and <jats:italic>redundancy</jats:italic> . This leads to four distinct forms of fault tolerance and to two main phases in achieving them: <jats:italic>detection</jats:italic> and <jats:italic>correction</jats:italic> . We show that this can help to reveal inherently fundamental structures that contribute to understanding and unifying methods and terminology. By doing this, we survey many existing methodologies and discuss their relations. The underlying system model is the close-to-reality asynchronous message-passing model of distributed computing. </jats:p>

<jats:p>Deductive databases result from the integration of relational database and logic programming techniques. However, significant problems remain inherent in this simple synthesis from the language point of view. In this paper, we discuss these problems from four different aspects: complex values, object orientation, higher-orderness, and updates. In each case, we examine four typical languages that address the corresponding issues.</jats:p>

<jats:p>Active database systems support mechanisms that enable them to respond automatically to events that are taking place either inside or outside the database system itself. Considerable effort has been directed towards improving understanding of such systems in recent years, and many different proposals have been made and applications suggested. This high level of activity has not yielded a single agreed-upon standard approach to the integration of active functionality with conventional database systems, but has led to improved understanding of active behavior description languages, execution models, and architectures. This survey presents the fundamental characteristics of active database systems, describes a collection of representative systems within a common framework, considers the consequences for implementations of certain design decisions, and discusses tools for developing active applications.</jats:p>

<jats:p>Computer-supported cooperative work (CSCW) holds great importance and promise for modern society. This paper provides an overview of seventeen papers comprising a symposium on CSCW. The overview also discusses some relationships among the contributions made by each paper, and places those contributions into a larger context by identifying some of the key challenges faced by computer science researchers who aim to help us work effectively as teams mediated through networks of computers. The paper also describes why the promise of CSCW holds particular salience for the U.S military. In the context of a military setting, the paper describes five particular challenges for CSCW researchers. While most of these challenges might seem specific to military environments, many others probably already face similar challenges, or soon will, when attempting to collaborate through networks of computers. To support this claim, the paper includes a military scenario that might hit fairly close to home for many, and certainly for civilian emergency response personnel. After discussing the military needs for collaboration technology, the paper briefly outlines the motivation for a recent DARPA research program along these lines. That program, called Intelligent Collaboration and Visualization, sponsored the work reported in this symposium.</jats:p>

<jats:p>We introduce the concept of semantic multicast to implement a large-scale shared interaction infrastructure providing mechanisms for collecting, indexing, and disseminating the information produced in collaborative sessions. This infrastructure captures the interactions between users (as video, text, audio and other data streams) and promotes a philosophy of filtering, archiving, and correlating collaborative sessions in user and context sensitive groupings. The semantic multicast service efficiently disseminates relevant information to every user engaged in the collaborative session, making the aggregated streams of the collaborative session available to the correct users at the right amount of detail. This contextual focus is accomplished by introducing proxy servers to gather, annotate, and filter the streams appropriate for specific interest groups. Users are subscribed to appropriate proxies, based on their profiles, and the collaborative session becomes a multi-level multicast of data from sources through proxies and to user interest groups.</jats:p>

<jats:p>This paper presents a framework for sharing JavaBeans applications in real-time synchronous collaboration. A generic collaboration bus provides a plug-and-play environment that enables collaboration with applications that may or may not be collaboration aware. Research on knowledge-based quality-of-service management and multimodel human/machine interface is described.</jats:p>

<jats:p> In distributed collaborative virtual environments, participants are often embodied or represented in some form within a virtual world. The representations take many different forms and are often driven by limitations in the available technology. Desktop Web based environments typically use textual or two dimensional representations, while high end environments use motion trackers to embody a participant and their actions in an <jats:italic>avatar</jats:italic> or human form. This paper describes this wide range of virtual user representations and their creation and performance issues investigated as part of the Human-Computer Symbiotes project within DARPA's Intelligent Collaboration and Visualization (IC&amp;V) program. </jats:p>