1,721,237 research outputs found
Asymmetric synthesis of all stereoisomers of the strigol analogue GR24. Dependence of absolute configuration on stimulatory activity of Striga hermonthica and Orobanche crenata seed germination
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28336.pdf (Publisher’s version ) (Open Access
Soft computing in finance and economics
Get PDFThe field of Soft Computing covers a wide range of techniques that are tolerant to the presence of uncertainty and imprecision. This feature is key in areas like Finance and Economics, where the opposite is rather the exception than the rule. For this reason, there is a growing interest in applications of the mentioned toolkit in the domain. This special track intends to address that demand introducing a diverse set of papers that cover a wide range of novel techniques and interesting solutions in core areas of application. All of them represent substantial contributions to the literature.The authors acknowledge financial support granted by the Spanish Ministry of Science under contract TIN2011-28336 (MOVES
Clustering technique for large-scale home care crew scheduling problems
Get PDFThe Home Health Care Scheduling Problem involves allocating professional caregivers to patients' places of residence to meet service demands. These services are regular in nature and must be provided at specific times during the week. In this paper, we present a heuristic with two tie-breaking mechanisms suitable for large-scale versions of the problem. The greedy algorithm merges service lots to minimize the accumulated unproductive time. As a result, the solution is restructured in such a way as to increase its efficiency. The approach is tested on a real-world large instance of the problem for a company whose current resource allocation is inefficient. The solutions are benchmarked against the current service assignment and those obtained by a Ward clustering algorithm, and the results show an improvement in efficiency and cost.The authors acknowledge financial support granted by the Spanish Ministry of Science and Innovation under grant TIN2011-28336 (MOVES)
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
Optimizing the number of electrodes and spatial filters for Brain-Computer Interfaces by means of an evolutionary multi-objective approach
Get PDFObtaining high accuracy classification from Brain Computer Interfaces require to attach many electrodes on the scalp of subjects. On the other hand, their placement on the scalp involves generally a laborious and time consuming process. Therefore, it is important for the practitioner to estimate how many electrodes, and which ones, are needed to obtain the required accuracy. With this purpose, a multi-objective formulation is proposed in order to obtain a set of solutions (Pareto front) that represent all the optimal tradeoffs between the number of channels and the classification accuracy, from where the practitioner can choose. Additionally, previous research has shown that classification accuracy highly depends on the proper tuning of the filter used to preprocess the electroencephalogram. Therefore, in this work, the Non-dominated Sorting Genetic Algorithm II is used for optimizing both the number of electrodes and the classification error, through the optimization of a spatial filter encoded in the solution. The fact that the filter is part of the solution allows to determine which electrodes are to be selected by using a simple threshold, instead of a long binary mask as in other approaches. Empirical results show that indeed, the simultaneous optimization of the spatial filter and selected electrodes is crucial to obtain a low classification error, compared to other approaches that reduce the number of electrodes but do not modify the filter.This work has been funded by the Spanish Ministry of Science under contract
TIN2011-28336 (MOVES project)
Extended mean-variance model for reliable evolutionary portfolio optimization
Get PDFReal world optimization of financial portfolios pose a challenging multiobjective problem that can be tackled using Evolutionary Algorithms. The fact that the optimization process is subject to the presence of uncertainty concerning asset returns is likely to lead to unreliable solutions. This work suggests extending the classic mean-variance optimization problem with a third explicit robustness objective. This results on sets of portfolios that can be subsequently grouped together according to their reliability. This additional information allows for a better informed decision making regarding asset allocation. © 2014 - IOS Press and the authors. All rights reserved.Financial support granted by the Spanish Ministry of Science under contract TIN2011-28336 (MOVES)
Automatic design of noncryptographic hash functions using genetic programming
Get PDFNoncryptographic hash functions have an immense number of important practical applications owing to their powerful search properties. However, those properties critically depend on good designs: Inappropriately chosen hash functions are a very common source of performance losses. On the other hand, hash functions are difficult to design: They are extremely nonlinear and counterintuitive, and relationships between the variables are often intricate and obscure. In this work, we demonstrate the utility of genetic programming (GP) and avalanche effect to automatically generate noncryptographic hashes that can compete with state-of-the-art hash functions. We describe the design and implementation of our system, called GP-hash, and its fitness function, based on avalanche properties. Also, we experimentally identify good terminal and function sets and parameters for this task, providing interesting information for future research in this topic. Using GP-hash, we were able to generate two different families of noncryptographic hashes. These hashes are able to compete with a selection of the most important functions of the hashing literature, most of them widely used in the industry and created by world-class hashing experts with years of experience.This work has been funded by the Spanish Department of Science and Innovation (Ministerio de Ciencia e Innovación), under the research project Gestión de Movilidad Eficiente y Sostenible (TIN2011‐28336
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