Catálogo de publicaciones - revistas

<jats:p>The security of information systems is a serious issue because computer abuse is increasing. It is important, therefore, that systems analysts and designers develop expertise in methods for specifying information systems security. The characteristics found in three generations of general information system design methods provide a framework for comparing and understanding current security design methods. These methods include approaches that use checklists of controls, divide functional requirements into engineering partitions, and create abstract models of both the problem and the solution. Comparisons and contrasts reveal that advances in security methods lag behind advances in general systems development methods. This analysis also reveals that more general methods fail to consider security specifications rigorously.</jats:p>

<jats:p> Finding a binary encoding of symbolic control states, such that the implementation area of a digital control unit is minimized is well known to be NP-complete. Many heuristic algorithms have been proposed for this <jats:italic>state assignment problem</jats:italic> . The objective of this article is to present a comprehensive survey and systematic categorization of the various techniques, in particular, for synchronous sequential circuits with nonmicroprogrammed implementations. The problem is partitioned into the generation and the satisfaction of coding constraints. Three types of coding constraints—adjacency, covering, and disjunctive constraints—are widely used. The constraint satisfaction algorithms are classified into column-based, row-based, tree-based, dichotomy-based, and global minimization approaches. All of them are illustrated with examples. Special coding requirements and testability-related aspects of state assignment are considered in a separate section. Different implementations of the algorithms presented are also compared. </jats:p>

<jats:p>The development of computing applications by the people who have direct need for them in their work has become commonplace. During the 1980s, development of applications by “end users” accelerated and became a key management and research concern. Known as “end-user computing,” the phenomena and research associated with this trend cross a variety of disciplines. This article critically surveys the published literature on end-user computing (EUC) management according to a comprehensive research model. The article introduces the EUC management research model, identifies prior research contributions, and offers guideline for the future. The focal points of the model are two EUC management components which represent two different levels of theorizing found in the literature. The first level focuses on the organization factors of strategy, technology, and management action. The second level focuses on the individual factors of end user, task, tool, and end-user action. The remainder of the model includes factors typically investigated as the antecedents (context) and consequences (outcomes) of EUC. More than 90 English-language articles published from 1983-1990 are mapped into the model. Specific variables for each factor are identified; research streams are interpreted; findings are synthesized; and gaps in our knowledge are highlighted. We then raise a number of substantive and methodological issues that need to be addressed and suggest two themes we envision as important for EUC management research in the 1990s: EUC as an extension of organizational computing and EUC as a social learning phenomenon. Guidance is offered for using these theme to inform future research.</jats:p>

<jats:p> Probabilistic, or randomized, algorithms are fast becoming as commonplace as conventional deterministic algorithms. This survey presents five techniques that have been widely used in the design of randomized algorithms. These techniques are illustrated using 12 randomized algorithms—both sequential and distributed— that span a wide range of applications, including: <jats:italic>primality testing</jats:italic> (a classical problem in number theory), <jats:italic>interactive probabilistic proof systems</jats:italic> (a new method of program testing), <jats:italic>dining philosophers</jats:italic> (a classical problem in distributed computing), and <jats:italic>Byzantine agreement</jats:italic> (reaching agreement in the presence of malicious processors). Included with each algorithm is a discussion of its correctness and its computational complexity. Several related topics of interest are also addressed, including the theory of probabilistic automata, probabilistic analysis of conventional algorithms, deterministic amplification, and derandomization of randomized algorithms. Finally, a comprehensive annotated bibliography is given. </jats:p>

<jats:p> This survey characterizes an emerging research area, sometimes called <jats:italic>coordination theory</jats:italic> , that focuses on the interdisciplinary study of coordination. Research in this area uses and extends ideas about coordination from disciplines such as computer science, organization theory, operations research, economics, linguistics, and psychology. </jats:p> <jats:p> A key insight of the framework presented here is that coordination can be seen as the process of <jats:italic>managing dependencies</jats:italic> among activities. Further progress, therefore, should be possible by characterizing different kinds of dependencies and identifying the coordination processes that can be used to manage them. A variety of processes are analyzed from this perspective, and commonalities across disciplines are identified. Processes analyzed include those for managing <jats:italic>shared resources, producer/consumer relationships, simultaneity constraints</jats:italic> , and <jats:italic>task/subtask dependencies</jats:italic> . </jats:p> <jats:p>Section 3 summarizes ways of applying a coordination perspective in three different domains:(1) understanding the effects of information technology on human organizations and markets, (2) designing cooperative work tools, and (3) designing distributed and parallel computer systems. In the final section, elements of a research agenda in this new area are briefly outlined.</jats:p>

<jats:p> This paper critically surveys methods for the automated probabilistic diagnosis of large multiprocessor systems. In recent years, much of the work on system-level diagnosis has focused on probabilistic methods, which can diagnose intermittently faulty processing nodes and can be applied in <jats:italic>general</jats:italic> situations on <jats:italic>general</jats:italic> interconnection networks. The theory behind the probabilistic diagnosis methods is explained, and the various diagnosis algorithms are described in simple terms with the aid of a running example. The diagnosis methods are compared and analyzed, and a chart is produced, showing the comparative advantages of the various diagnosis algorithms on the basis of several factors important to the probabilistic diagnosis. </jats:p>

<jats:p>Disk arrays were proposed in the 1980s as a way to use parallelism between multiple disks to improve aggregate I/O performance. Today they appear in the product lines of most major computer manufacturers. This article gives a comprehensive overview of disk arrays and provides a framework in which to organize current and future work. First, the article introduces disk technology and reviews the driving forces that have popularized disk arrays: performance and reliability. It discusses the two architectural techniques used in disk arrays: striping across multiple disks to improve performance and redundancy to improve reliability. Next, the article describes seven disk array architectures, called RAID (Redundant Arrays of Inexpensive Disks) levels 0–6 and compares their performance, cost, and reliability. It goes on to discuss advanced research and implementation topics such as refining the basic RAID levels to improve performance and designing algorithms to maintain data consistency. Last, the article describes six disk array prototypes of products and discusses future opportunities for research, with an annotated bibliography disk array-related literature.</jats:p>