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1.
In this paper we develop a study on several types of parallel genetic algorithms (PGAs). Our motivation is to bring some uniformity to the proposal, comparison, and knowledge exchange among the traditionally opposite kinds of serial and parallel GAs. We comparatively analyze the properties of steady-state, generational, and cellular genetic algorithms. Afterwards, this study is extended to consider a distributed model consisting in a ring of GA islands. The analyzed features are the time complexity, selection pressure, schema processing rates, efficacy in finding an optimum, efficiency, speedup, and resistance to scalability. Besides that, we briefly discuss how the migration policy affects the search. Also, some of the search properties of cellular GAs are investigated. The selected benchmark is a representative subset of problems containing real world difficulties. We often conclude that parallel GAs are numerically better and faster than equivalent sequential GAs. Our aim is to shed some light on the advantages and drawbacks of various sequential and parallel GAs to help researchers using them in the very diverse application fields of the evolutionary computation. 相似文献
2.
Recently, we developed a GIS-Integrated Integral Risk Index (IRI) to assess human health risks in areas with presence of environmental pollutants. Contaminants were previously ranked by applying a self-organizing map (SOM) to their characteristics of persistence, bioaccumulation, and toxicity in order to obtain the Hazard Index (HI). In the present study, the original IRI was substantially improved by allowing the entrance of probabilistic data. A neuroprobabilistic HI was developed by combining SOM and Monte Carlo analysis. In general terms, the deterministic and probabilistic HIs followed a similar pattern: polychlorinated biphenyls (PCBs) and light polycyclic aromatic hydrocarbons (PAHs) were the pollutants showing the highest and lowest values of HI, respectively. However, the bioaccumulation value of heavy metals notably increased after considering a probability density function to explain the bioaccumulation factor. To check its applicability, a case study was investigated. The probabilistic integral risk was calculated in the chemical/petrochemical industrial area of Tarragona (Catalonia, Spain), where an environmental program has been carried out since 2002. The risk change between 2002 and 2005 was evaluated on the basis of probabilistic data of the levels of various pollutants in soils. The results indicated that the risk of the chemicals under study did not follow a homogeneous tendency. However, the current levels of pollution do not mean a relevant source of health risks for the local population. Moreover, the neuroprobabilistic HI seems to be an adequate tool to be taken into account in risk assessment processes. 相似文献
3.
A cooperative game with transferable utilities– or simply a TU-game – describes a situation in which players can obtain certain payoffs by cooperation. A solution concept for these games is a function which assigns to every such a game a distribution of payoffs over the players in the game.
Famous solution concepts for TU-games are the Shapley value and the Banzhaf value. Both solution concepts have been axiomatized in various ways.
An important difference between these two solution concepts is the fact that the Shapley value always distributes the payoff
that can be obtained by the `grand coalition' consisting of all players cooperating together while the Banzhaf value does
not satisfy this property, i.e., the Banzhaf value is not efficient. In this paper we consider the normalized Banzhaf value which distributes the payoff that can be obtained by the `grand coalition' proportional to the Banzhaf values of the players.
This value does not satisfy certain axioms underlying the Banzhaf value. In this paper we introduce some new axioms that characterize
the normalized Banzhaf value. We also provide an axiomatization of the Shapley value using similar axioms.
Received: 10 April 1996 / Accepted: 2 June 1997 相似文献
4.
José Guimón Cristina Chaminade Claudio Maggi Juan Carlos Salazar-Elena 《Journal of International Management》2018,24(2):165-178
Over the last decade we have witnessed an unprecedented growth in the number of cross-border R&D investments towards large emerging countries such as China and India. However, small middle-income countries have played a marginal role as recipients of R&D-related FDI despite increasing policy efforts. In particular, several Latin American countries have recently launched new policy programs with the aim of attracting this kind of investments, but it remains uncertain whether public incentives can be useful to compensate for other locational disadvantages. The case of Chile provides an interesting empirical setting to explore these issues because during the last decade its government has been actively promoting R&D-related FDI through a new policy mix. This article suggests that for national innovation systems to benefit from the attraction of internationally-mobile R&D it is critical for public policies to ensure that appropriate linkages are established with local actors that hold absorptive capacities. Equally important for a small emerging economy like Chile is to prioritize R&D-related FDI in strategic technology niches where the country can realistically attain critical mass. 相似文献
5.
Alfaro Moreno Ana Karina Núñez Velázquez José Javier 《Social indicators research》2019,142(3):911-946
Social Indicators Research - This study analyzes the evolution of salary polarization in the Spanish labor market. The paper proposes the use of mixed distributions to examine the consequences of... 相似文献
6.
7.
Hèla Yousfi 《European Management Journal》2019,37(5):625-636
International development agencies believe that by adopting institutional reforms based on the best practices that have proved effective elsewhere, so-called « developing countries » could take their places in the globalised economy. Based on a case study carried out on the implementation challenges of a decentralization project in Tunisia, I will argue by using an interpretive approach that this thesis is not sustained. This article shows that institutions cannot be reduced to their technical functions but that they are based on particular collective imaginaries that ground what is legitimate or not and structure the relationship of individuals to power and the meaning given to their actions. It encourages the consideration of cultural framework of meaning; these local cultural references structure the governance modalities of a society, understood in terms of the modalities of exercise of power in a given group (state, company, local authority, etc.). It advocates the necessity to move from a technic-prone approach in the implementation of institutional changes towards a socio-cultural approach that integrates the local expectations of what “good governance” should be and on which depends the legitimacy of institutions and their appropriation by local populations. 相似文献
8.
Víctor Leiva Shuangzhe Liu Lei Shi Francisco José A. Cysneiros 《Journal of applied statistics》2016,43(4):627-642
We propose an influence diagnostic methodology for linear regression models with stochastic restrictions and errors following elliptically contoured distributions. We study how a perturbation may impact on the mixed estimation procedure of parameters in the model. Normal curvatures and slopes for assessing influence under usual schemes are derived, including perturbations of case-weight, response variable, and explanatory variable. Simulations are conducted to evaluate the performance of the proposed methodology. An example with real-world economy data is presented as an illustration. 相似文献
9.
Gómez P González MJ Gil F Lupiáñez JL Moreno MF Rico L Romero I 《Evaluation and program planning》2007,30(2):149-160
The establishment of the European Higher Education Area has involved specifying lists of professional competencies that programs are expected to develop, and with this the need for procedures to measure how every course within a higher education program is aligned with the program's competencies. We propose an instrument for characterizing this alignment, a process that we call assessing the relevance of a course. Using information from the course syllabus (objectives, contents and assessment scheme), our instrument produces indicators for characterizing the syllabus in terms of a competence list and for assessing its coherence. Because assessment involves quality, the results obtained can also be used to revise and improve the course syllabus. We illustrate this process with an example of a methods course from a mathematics teacher education program at a Spanish university. 相似文献
10.
Inmaculada García José Alberto Molina María Navarro 《Journal of Family and Economic Issues》2007,28(4):546-565
This paper first identifies the determinants of spouses’ satisfaction levels within the household with respect to their leisure
time and, secondly, characterizes whether their preferences have some degree of altruistic or egoistic character in regard
to this particular satisfaction. To that end, it formulates a theoretical framework from the collective family model whose
stochastic formulations are estimated for 14 EU countries. The general empirical results first reveal that the presence of
children has a significantly negative impact on the leisure satisfaction of both spouses. Then, increases in individual incomes
lead to lower own leisure satisfaction levels. Both husbands and wives show egoistic behavior with respect to the labor and
non-labor incomes (wage rate) of their respective spouses’ satisfaction levels.
相似文献
María NavarroEmail: |