1,720,982 research outputs found
PRODUCT-FORM SYNTHESIS OF QUEUEING NETWORKS.
No full textThe mathematics of product-form queueing networks has traditionally dealt with the 'analysis' of computer systems. That is, the system is assumed to be given and the question of how it performs is answered. In this paper the opposite process of system 'synthesis' is dealt with: i. e. , we answer the question of what the system topology and parameters should be in order to achieve a given performance objective. Possible research and industry applications range from the hierarchical top-down design of software systems to the management and design of computer installations
An Extension of Norton's Theorem for Queueing Networks
No full textGiven a closed BCMP queueing network, the problem is considered of studying the behavior of any subsystem σ without solving for the entire system. This paper proves that this is possible for σ consisting of any number of queues, arbitrarily interfacing the rest of the system, thus generalizing the classic CHW theorem, also known as Norton's theorem. A general flow-equivalent solution procedure is given and its computational complexity is compared with that of the product-form and the exact aggregation procedure. The relative merits of these procedures are also expressed in terms of σ's cardinality. Copyright © 1982 by The Institute of Electrical and Electronics Engineers, Inc
A simulation tool for the design of satellite data-flow handling system: Workload characterization
No full textabstrac
Automatic derivation of software performance models from CASE documents
No full textLifecycle validation of software performance (or prediction of the product ability to satisfy the user performance-requirements) is based on the automatic derivation of software performance models from CASE documents or rapid prototypes. This paper deals with the CASE document alternative. After a brief overview of existing automatic derivation methods, it introduces a method that unifies existing techniques that use CASE documents. The method is step-wise clear, can be used from the early phases of the software lifecycle, is distributed-software oriented, and can be easily incorporated into modern (e.g., UML-based) CASE tools. The method enables the software designer with no specific knowledge of performance theory to predict at design time the performance of various final product alternatives. The designer does only need to feed the CASE documents into the performance model generator. The paper carries on an application case study that deals with the development of distributed software, where the method is used to predict the performance of different distributed architectures the designer could select at preliminary design time to obtain the best performing final product. The method can be easily incorporated into modern object-oriented software development environments to encourage software designers to introduce lifecycle performance validation into their development best practices
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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