1,721,013 research outputs found
What Foundations does the RM-ODP need?
Full text linkThis position paper revisits the requirements for the set of Foundation Concepts for the ODP Reference Model and the approach originally taken to satisfying them. It then examines, in the light of experience, the areas where the Foundations have subsided, and areas where extensions need to be built. The aim is to provide a starting point for discussion on requirements to change the Foundations document
Black Cats and Yellow Birds - What do Viewpoint Correspondences Do?
Full text linkThe ODP Reference Model is one of a number of specification frameworks which are based on the definition of a set of viewpoints that are coupled together by the definition of correspondences between terms. Wherever a correspondence is declared, any real world entity that is represented by a term in one viewpoint must also satisfy the requirements placed by the occurrence of the corresponding term in the other viewpoint. Although this idea represents an intuitively simple and satisfying way of talking about the design of complex systems, the idea of a correspondence is not as simple as it might, at first sight, appear. This paper uses simple examples to illustrate some of the complexities resulting from the coupling of object models and examines the consequences for claims of conformance to the complete system of specifications
Policy Specification: Meeting Changing Requirements without Breaking the System Design Contract
No full textThere has been a great deal of interest in recent years in the use of policies to simplify system management and to reduce costs. However, the major focus has been on the development of techniques with the greatest expressive power possible, generally viewing the policy authoring as a self-contained activity performed by experts who understand the aims of and constraints on the system being managed. A system is normally designed to meet agreed requirements and objectives, which can be seen as constituting a design contract for the system. The aim in introducing policies should be to allow flexibility to meet changing circumstances without violating the guarantees given by this contract. This paper looks at policy specification as a step in the incremental design of systems and examines how policies need to be constrained in order to preserve the over all design objectives for the system being managed. It proposes a specification architecture for policies, discusses how it might be used, and considers how well-suited some existing specification languages and tools are to supporting this architecture
A architecture for MHEG objects
Full text linkHypermedia applications are one of the most recent and most demanding computer uses. It is accepted that one of the main impediments to their widespread use is the lack of standards, and the lack of Open Systems with the possibility of having documents interchangeable between different hardware and software platforms. Several standards are emerging, one of which is the one being developed by the ISO/IEC WG12 known as the Multimedia and Hypermedia Information Coding Expert Group (MHEG). As desktop systems become more powerful, one of the main users of hypermedia applications is the home market. Therefore it is important to have standards and applications suitable for those platforms. This work reviews existing proposals for hypermedia architectures and interchange standards. It then assesses the suitability of the MHEG standard for use in open, distributed, and extensible hypermedia systems. An architecture for the implementation of MHEG objects taking into account the limitations imposed by current desktop computers is also proposed. To assess the suitability of the proposed architecture, a prototype has been implemented. An analysis of the performance obtained in the prototype is presented and conclusions on the requirements for future implementations drawn. Finally, some suggestions to improve the MHEG standard are made
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
Constructing efficient self-organising application layer multicast overlays
Full text linkThis thesis investigates efficient techniques to build both low cost (i.e. low resource usage) and low delay ALM trees. We focus on self-organising distributed proposals that use limited information about the underlying physical network, limited coordination between the members, and construct overlays with bounded branching degree subject to the bandwidth constraint of each individual member
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
- …
