1,720,970 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Modular action language ALM for dynamic domain representation
No full textThe goal of this dissertation is to define a modular action language, ALM, for the elaboration tolerant representation of knowledge about medium-size dynamic domains. Discrete dynamic domains can be theoretically captured by transition diagrams. The problem of concisely and precisely specifying such diagrams was the subject of study for several decades. Action languages were introduced as a solution to this problem. However, traditional action languages are not suitable for the specification of medium and large size domains because they lack the means for structuring knowledge and do not thoroughly address the problem of representing objects of the domain. Language ALM addresses these issues.
The task of designing a modular action language is a relevant one in the field of AI: it is the first step towards the creation of intelligent agents capable of reasoning about, or acting in a wide variety of dynamic environments. More importantly, the design of ALM allows us to better understand how to represent knowledge. Other modular action languages exist (e.g., MAD, TAL-C), but they correspond to different intuitions and knowledge representation styles. ALM is an alternative to these languages.
The design of ALM was not a trivial task. ALM is intended to be a simple but powerful language that would allow for elegant representations of a variety of
dynamic domains. Hence, our main design and evaluation criteria were its expressive power and its simplicity and elegance. Generally, there is a tension between the two, which makes it challenging to design a modular action language.
Our language is intended to facilitate the creation of knowledge representation libraries, as well as the stepwise development, testing, and readability of a knowledge base. This is achieved by separating the description of a domain into two parts: a general theory, which consists of several modules that can be reused in modeling other domains, and an interpretation of this theory, which is particular to the specific domain. As well, ALM introduces classes of objects that can be described in terms of previously defined ones. Classes have attributes that are optional, a feature that contributes to the elaboration tolerance of the language. We tested that these and other features of our language accomplish our goal by modeling several domains, both commonsensical (e.g., motion) and specialized (e.g., cell division), in ALM.
We were satisfied with the formalizations that resulted and with the capabilities of
our language. In this dissertation, we formally present language ALM, illustrate the methodology of its use for knowledge representation and problem solving, report on an application of ALM to question answering, and compare our language with the closest existing modular action language, MAD
Security policy management in federated computing environments
Get PDFThe default Java implementation for security policies based on policy files doesn’t comply with the specific needs of metacomputing environments. Managing a large number of policy files for all Java runtime systems in the metacomputing system doesn’t scale. This paper presents a federated approach for security policy management in Java-based metacomputing systems. Security policies are stored in a policy base, which is managed by a policy service provider (Policer). The policy base and its Policer are replicated and the replicated policy bases are synchronized with each other in order to avoid a single point of failure. Any bootstrapping service provider gets its security policy dynamically from any available Policer in the network. The proposed solution ensures uniform policy-based authorization for all the services in the SORCER metacomputing environment through the use of the dynamic policy management methodology
D-FLAT^2: Subset Minimization in Dynamic Programming on Tree Decompositions Made Easy
No full textMany problems from the area of AI have been shown tractable for bounded treewidth. In order to put such results into practice, quite involved dynamic programming (DP) algorithms on tree decompositions have to be designed and implemented. These algorithms typically show recurring patterns that call for tasks like subset-minimization. In this paper we present D-FLAT^2, a system that allows one to obtain DP algorithms (specified in ASP) from simpler principles, where the DP formalization of subset-minimization is performed automatically.
We illustrate the method at work by providing several DP algorithms - given in form of ASP programs - that are more space-efficient than existing solutions, while featuring improved readability, reuse and therefore maintainability of ASP code. Experiments show that our approach also yields a significant improvement in runtime performance
Variations on the Author
Get PDF“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
Get PDFWe 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
Program Synthesis Using Example Propagation
No full textWe present scrybe, an example-based synthesis tool for a statically-typed functional programming language, which combines top-down deductive reasoning in the style of λ2 with SMYTH-style live bidirectional evaluation. During synthesis, example constraints are propagated through sketches to prune and guide the search. This enables SCRYBE to make more effective use of functions provided in the context. To evaluate our tool, it is run on the combined, largely disjoint, benchmarks of λ2 and MYTH. SCRYBE is able to synthesize most of the combined benchmark tasks.</p
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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