1,720,985 research outputs found
From Agent Theory to Agent Construction: A Case Study
No full textAbstract. There is a growing body of work that concentrates on theoretical aspects of agents and multi-agent systems, and a complementary body of work concerned with building practical systems. However, the two have typically been unrelated. This gap between the theory and practice of intelligent agents has only relatively recently begun to be addressed. In this paper we describe the construction of an agent simulation environment that is based strongly on a formal theory of agent systems, but which is intended to serve in exactly this way as a basis for practical development. The paper briefly introduces the theory, then describes the system and the simple reactive agents built with it, but most importantly shows how it reflects the theoretical framework and how it facilitates incremental agent design and implementation. Using this example as a case-study, some possibilities for a methodology for the development of agent systems are discussed.
London EC2Y 8HB
No full textThe Variance-Gamma model has analytical formulae for the values of European calls and puts. These formulae have to be computed using numerical methods. In general, option valuation may require the use of numerical methods including PDE methods, lattice methods, and Monte Carlo methods. We investigate the use of Monte Carlo methods in the Variance-Gamma model. We demonstrate how a gamma bridge process can be constructed. Using the bridge together with stratified sampling we obtain consider-able speed improvements over a plain Monte Carlo method when pricing path-dependent options. The method is illustrated by pricing lookback, average rate and barrier options in the Variance-Gamma model. We find the method is up to around 400 times faster than plain Monte Carlo. ∗Corresponding author. Claudia Ribeiro gratefully acknowledges the support of Fundação para a Ciência e a Tecnologia and Faculdade de Economia, Universidade do Porto. The paper has benefited from comments from Lynda McCarthy. 1
Ergodic Pumping: a mechanism to drive biomolecular conformation changes
No full textWe propose that a significant contribution to the power stroke of myosin and similar conformation changes in other biomolecules is the pressure of a single molecule (e.g. a phosphate ion) expanding a trap, a mechanism we call “ergodic pumping”. We demonstrate the principle with a toy computer model and discuss the mathematics governing the evolution of slow degrees of freedom in large Hamiltonian systems. We indicate in detail how the mechanism could fit with known features of the myosin cycle. Many other biomolecular conformation changes could be driven in part by ergodic pumping. We suggest the use of ergodic pumping as a design principle in nanobiotechnology.
Improved Compressions of Cube-Connected Cycles Networks
No full textWe present a new technique for the embedding of large cube-connected cycles networks (CCC) into smaller ones, a problem that arises when algorithms designed for an architecture of an ideal size are to be executed on an existing architecture of a fixed size. Using the new embedding strategy, we show that the CCC of dimension l can be embedded into the CCC of dimension k with dilation 1 and optimum load for any k; l 2 IN , k 8, such that 5 3 + c k ! l k 2, c k = 4k + 3 3 \Delta 2 2=3k , thus improving known results. Our embedding technique also leads to improved dilation 1 embeddings in the case 3 2 ! l k 5 3 + c k . Index Terms Parallel computations, parallel architectures, interconnection networks, graph embedding, network simulation, cube-connected cycles network. 1 Introduction Over the past few years, a lot of research has been done in the field of interconnection networks for parallel computer architectures (for an overview, cf. [19]). Much of the work has been focused..
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
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
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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