1,720,997 research outputs found
Hybrid Metaheuristics: Preface to the proceedings of HM2006
No full textThe International Workshop on Hybrid Metaheuristics reached its third edition with HM 2006. The active and successful participation in the past editions was a clear indication that the research community on metaheuristics and related areas felt the need for a forum to discuss specific aspects of hybridization of metaheuristics. The selection of papers for HM 2006 consolidated some of the mainstream issues that have emerged from the past editions. Firstly, there are prominent examples of effective hybrid techniques whose design and implementation were motivated by challenging real-world applications. A second important issue is that the research community on metaheuristics has become increasingly interested in and open to techniques and methods known from artificial intelligence (AI) and operations research (OR). The awareness of the need for a sound experimental methodology is a third keypoint. This aspect has gained more relevance and currency, even though there are still no widely agreed standard methodologies. As research on hybrid metaheuristics is mostly based on experimental methods, similar standards to those found in the evaluation of experiments in natural sciences can be expected. Scientific testing, a fourth notable aspect, emerges as a fundamental methodology for understanding the behavior of algorithms. The goal of scientific testing is to abstract from actual implementations and study, empirically and through predictive models, the effect of algorithmic components. This research approach can be particularly useful in the case of conjectures on metaheuristic algorithm behavior that, while being widespread in the community, have not yet been the subject of validation. Finally, a tendency to reconsider hybrid metaheuristics from a higher and more general perspective is emerging. Providing classifications, systematic analyses and surveys on important branches underlines a certain maturity of the relatively young field.
For the future, we envision a scenario in which some challenges have to be faced: – It should become common practice that experimental analysis meets high quality standards. This empirical approach is absolutely necessary to produce objective and reproducible results and to anchor the successes of metaheuristics in real-world applications. – Hybrid metaheuristic techniques have to be openly compared not just among themselves but also with state-of-the-art methods, from whatever field they are. By following this approach, researchers would be able to design techniques that meet the goal of solving a real-world problem and to consider the other approaches as rich sources of design components and ideas. – Scientific testing and theoretical models of algorithms for studying their behavior are still confined to a limited area of research. We believe that, by being able to explain rigorously algorithm behavior by means of sound empirical investigation and formal models, researchers would give the field a firmer status and give support to the development of real-world applications. The achievement of these goals will take some time in view of the difficult theoretical and practical problems involved in these challenges. Nevertheless, research is very active and has already produced some remarkable results and studies in this direction
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
Hybrid Metaheuristics: An Emerging Approach to Optimization
No full textWhen facing complex and unknown problems, it is very natural to use rules of thumb, common sense, trial and error, so called heuristics in order to find possible answers. Such approaches are at first sight quite different from scientific approaches to a problem, which are usually based on characterizations, deductions, hypotheses and experiments. It is common knowledge that many heuristic criteria and strategies that are used to find good solutions for particular problems share common aspects and are often independent of the problem itself.
In the computer science and artificial intelligence community the term metaheuristic was created and is now well accepted for such general techniques that are not specific to one particular problem. Genetic and evolutionary algorithms, tabu search, simulated annealing, iterated local search, ant colony optimization, scatter search, etc. are typical representatives falling under this generic term. Research in metaheuristics has been very active during the last decades, which is easy to understand when looking at the wide spectrum of fascinating problems that have been successfully tackled and the beauty of the techniques, many of them inspired by nature. Though many combinatorial optimization problems are very hard to solve, it is incredible how good results can be achieved for many instances in practice by rather simple metaheuristic approaches.
These success stories let the researchers also focus on questions why a given metaheuristic is successful, what problem instance characteristics are most informative and which problem model is best for the metaheuristic of choice. Investigations on theoretical aspects began also to be studied and formal theories of some metaheuristics as such were developed. Questions as to which metaheuristic is the best for a given problem were quite common and, more prosaically, often led to a defensive attitude towards other metaheuristics.
It became also evident that the concentration on a sole metaheuristic is rather restrictive for advancing the state of the art when tackling both academic and practical optimization problems. A skilful combination of concepts of different metaheuristics can lead to more efficient behaviour and greater flexibility in many cases. The incorporation of typical operations research (OR) techniques, such as mathematical programming, can be very beneficial, too. Also, the combination of metaheuristics with other techniques known from artificial intelligence (AI), such as constraint programming and data mining, can be very fruitful. Combinations of metaheuristic components with components from other metaheuristics or from AI and OR techniques are called hybrid metaheuristics.
It is somethimes critisized that this unsharp definition does not exactly limit the scope of research in the field. We in contrary believe that this open concepts is a very positive aspect, because in the past indeed too strict boarderlines were often blocking creative research directions. A vivid research community is driven by new ideas and creativity, not by limitations.
In 2004, the editors of this book initiated with the First International Workshop on Hybrid Metaheuristics (HM 2004) a series of annual workshops that has given a forum to researchers who directed their work to integrative approaches that go beyond the borderline of a single metaheuristic. The growing interest in this workshop is an indication that typical questions as to the choice and tuning of parameters, the proper interaction of different algorithm components, the adequate analysis of results etc. do not live any longer in the shadows. With this background, it becomes evident that the field of hybrid metaheuristics clearly belongs to the field of experimental sciences and its strong interdisciplinarity fosters the cooperation among researchers with different expertise.
We feel that it is now time to provide a textbook on hybrid metaheuristics, that collects the most p..
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
