1,354,221 research outputs found
Computational Management Science, special issue
No full textNumero speciale della rivista Computational Management Science. Guest Editors A. Migdalas, P.M. Pardalos, Gerardo Torald
Nonlinear Optimization and Parallel Computing
No full textThe new computational technologies are having a very strong influence on numerical optimization, in several different ways. Many researchers have been stimulated by the need to either conform the existing numerical techniques to the new parallel architectures or to devise completely new parallel solution approaches. A mini-symposium on Parallel Computing in Nonlinear Optimization was held in Naples, Italy, September 2001, during the International Conference ParCo2001, in order to bring together researchers active in this field and to discuss and share their findings. Some of the papers presented during the mini-symposium, as well as additional contributions from other researchers are collected in this special issue. Clearly, two different trends, well representative for most of the current research activities, can be identified. Firstly, there is an attempt to encapsulate parallel linear algebra software and algorithms into optimization codes, particularly codes implementing interior point strategies for which the linear algebra issues are very critical, and secondly, there is an effort to devise new parallel solution strategies in global optimization, either for specific or general purpose problems, motivated by the large size and the combinatorial nature of them. In the present paper we review the literature on these trends and classify the contributed papers within this framework
A Hybrid Genetic—GRASP Algorithm Using Lagrangean Relaxation for the Traveling Salesman Problem
No full textHybridization techniques are very effective for the solution of combinatorial optimization problems. This paper presents a genetic algorithm based on Expanding Neighborhood Search technique (Marinakis, Migdalas, and Pardalos, Computational Optimization and Applications, 2004) for the solution of the traveling salesman problem: The initial population of the algorithm is created not entirely at random but rather using a modified version of the Greedy Randomized Adaptive Search Procedure. Farther more a stopping criterion based on Lagrangean Relaxation is proposed. The combination of these different techniques produces high quality solutions. The proposed algorithm was tested on numerous benchmark problems from TSPLIB with very satisfactory results. Comparisons with the algorithms of the DIMACS Implementation Challenge are also presented</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
Aging in the Contemporary Urban Context: The Mortality Rates of Older Residents in Genoa, Italy
No full textBackground and Aims: The development of contemporary urbanization and the consequent growing complexity of social life have to be related with the demographic ageing process, diffusely interesting more and more Wester as well non-Western societies (Phillipson, 2013). Understanding the lives of the increasing number of older residents within the rapid contextual changing of urban environments become a priority issue both for urban architects and social gerontologists, as well, especially for city decision makers (Scharf et al., 2002; Rodwin et al., 2006; Ogg and Bonvalet, 2007). This study assessed the association between the living conditions of older residents and the urban settings where they experience the ageing process. The main objective was to realize a secondary data analysis leading to an efficient decision support system, focused on a deeply detailed geo-mapping representation of the Genoa municipality (a metropolitan urban context of northern Italy describing an aging index equal to 235.9 in 2013, compared to the national mean value of 152.7 and the EU28 mean value of 117.7), in order to support local policy makers in evaluating the vulnerability risk for older residents and planning adequate urban interventions.
Methods: This was a secondary data analysis combined with a geo-referencing model. The study was realized on big datasets provided by the official statistical registry of the Municipality of Genoa, deepening the analysis to the tiniest possible level of territorial observation. In order to perform a very detailed examination of the contextual living conditions of older residents, we assessed at smallest city block level the association of standard mortality rates of over65s with several factors of social and structural exclusion, like the levels of isolation of older residents, the average income and education levels of the neighborhood, the degree of deterioration of the building environment. Data where analyzed through SPSS statistical software and geospatially represented by QGIS mapping system, providing a detailed map of the whole town describing though adequate alert indicators the different territorial risk for older residents of exposure to vulnerability.
Results: Standard mortality rates of over 65s resulted significantly higher within those city blocks evidencing highest levels of social exclusion, economic deprivation and environmental decay, with a major gender disadvantaged for female older people and for older residents living in suburban contexts. The geo-referenced representation of results provided a mapping alert system helpful for decision makers to plan adequate interventions of social and urban requalification.
Conclusions: Our study, beyond implicit ecological limitations, demonstrates, on the one hand, the importance of focusing a specific attention to inclusion and exclusion processes interesting older people in town environment, and, on the other hand, the opportunity of converting the already available and continuously updated datasets of city registry offices in useful planning tools, helping older residents to better experience later stages of life within the increasing complexity of the contemporary urban setting
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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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