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The use of optimal orthogonal array latin hypercube designs is proposed. Orthogonal arrays were proposed for constructing latin hypercube designs by Tang (1993). Such designs generally have better space filling properties than random latin hypercube designs. Even so, these designs do not necessarily fill the space particularly well. As a result, we consider orthogonal-array-based latin hypercube designs that try to achieve optimality in some sense. Optimization is performed by adapting strategies found in Morris & Mitchell (1995) and Ye et al. (2000). The strategies here search only orthogonal-array-based latin hypercube designs and, as a result, optimal designs are found in a more efficient fashion. The designs found are in general agreement with existing optimal designs reported elsewhere. 相似文献
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Johan A. Oldekop Lorenza B. Fontana Jean Grugel Nicole Roughton Emmanuel A. Adu‐Ampong Gemma K. Bird Alex Dorgan Marcia A. Vera Espinoza Sara Wallin Daniel Hammett Esther Agbarakwe Arun Agrawal Nurgul Asylbekova Clarissa Azkoul Craig Bardsley Anthony J. Bebbington Savio Carvalho Deepta Chopra Stamatios Christopoulos Emma Crewe Marie‐Claude Dop Joern Fischer Daan Gerretsen Jonathan Glennie William Gois Mtinkheni Gondwe Lizz A. Harrison Katja Hujo Mark Keen Roberto Laserna Luca Miggiano Sarah Mistry Rosemary J. Morgan Linda L. Raftree Duncan Rhind Thiago Rodrigues Sonia Roschnik Flavia Senkubuge Ian Thornton Simon Trace Teresa Ore Ren Mauricio Valds Bhaskar Vira Nicola Yeates William J. Sutherland 《Development policy review : the journal of the Overseas Development Institute》2016,34(1):55-82
The Sustainable Development Goals (SDGs) herald a new phase for international development. This article presents the results of a consultative exercise to collaboratively identify 100 research questions of critical importance for the post‐2015 international development agenda. The final shortlist is grouped into nine thematic areas and was selected by 21 representatives of international and non‐governmental organisations and consultancies, and 14 academics with diverse disciplinary expertise from an initial pool of 704 questions submitted by 110 organisations based in 34 countries. The shortlist includes questions addressing long‐standing problems, new challenges and broader issues related to development policies, practices and institutions. Collectively, these questions are relevant for future development‐related research priorities of governmental and non‐governmental organisations worldwide and could act as focal points for transdisciplinary research collaborations. 相似文献
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We use a sample of CEO appointments at US corporations over the years 1992–2004 to test the 'glass cliff' hypothesis, which posits that females are appointed to leadership positions at firms that are in a precarious financial condition. Our analysis utilizes three measures of stock-price-based financial performance and two distinct control samples of appointments of males to the CEO position. We find that corporate performance preceding CEO appointments tends to favor females, implying that females (males) are appointed to the CEO position largely at times when the firm is in relatively better (worse) financial health. Disaggregating the data by appointments in up versus down markets, at high-risk versus low-risk firms, and by calendar time yield similar conclusions. There appears to be no glass cliff facing female CEOs at US firms. Our findings suggest a need for additional research to identify where and for what types of positions this phenomenon is prevalent. 相似文献
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For exponentially distributed failure times under general progressive censoring schemes, testing procedures for ordered failure rates are proposed using the likelihood ratio principle. Constrained maximum likelihood estimators of the failure rates are found. The asymptotic distributions of the test statistics are shown to be mixtures of chi-square distributions. When testing the equality of the failure rates, a simulation study shows that the proposed test with restricted alternative has improved power over the usual chi-square statistic with an unrestricted alternative. The proposed methods are illustrated using data of survival times of patients with squamous carcinoma of the oropharynx. 相似文献
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For a two-dimensional contingency table of probabilities, the concept of symmetry around the main diagonal is well defined. Statistical hypothesis test of symmetry versus positive bias have also been explored. For tables of higher (three or more) dimensions, however, different concepts of symmetry are available. In this study, we consider statistical inference procedures of symmetry in partial tables versus various biases in three-dimensional tables. We find the maximum likelihood estimates of the cell probabilities and the asymptotic distribution of the likelihood ratio test statistic in each case. Simulation studies are used to investigate the sizes and powers of the tests. The methodologies developed are applied on real data sets. 相似文献
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Comparison functions and choice correspondences 总被引:1,自引:1,他引:0
In this paper, we introduce the concept of a comparison function, which is a mapping g that assigns numbers to ordered pairs of alternatives (x,y) with the property that g(x,y)=−g(y,x). The paper discusses how some well-known choice correspondences on tournaments such as the uncovered set, the minimal covering
set and the bipartisan set can be extended to this general framework. Axiomatic characterizations and properties are studied
for these correspondences.
Received: 4 November 1996/Accepted: 13 April 1998 相似文献
8.
We consider the problem of off-line throughput maximization for job scheduling on one or more machines, where each job has a release time, a deadline and a profit. Most of the versions of the problem discussed here were already treated by Bar-Noy et al. (Proc. 31st ACM STOC, 1999, pp. 622–631; http://www.eng.tau.ac.il/amotz/). Our main contribution is to provide algorithms that do not use linear programming, are simple and much faster than the corresponding ones proposed in Bar-Noy et al. (ibid., 1999), while either having the same quality of approximation or improving it. More precisely, compared to the results of in Bar-Noy et al. (ibid., 1999), our pseudo-polynomial algorithm for multiple unrelated machines and all of our strongly-polynomial algorithms have better performance ratios, all of our algorithms run much faster, are combinatorial in nature and avoid linear programming. Finally, we show that algorithms with better performance ratios than 2 are possible if the stretch factors of the jobs are bounded; a straightforward consequence of this result is an improvement of the ratio of an optimal solution of the integer programming formulation of the JISP2 problem (see Spieksma, Journal of Scheduling, vol. 2, pp. 215–227, 1999) to its linear programming relaxation. 相似文献
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We consider a model in which there is uncertainty over when a one-shot game will be played. We show how a mechanism designer
can implement desirable outcomes in certain economic games by manipulating only the probability that the game is played in
a given round while leaving all other aspects of the game unchanged. We also show that if there is no discounting, this uncertainty
imparts a sequential structure that is almost mathematically equivalent to a repeated version of the game with discounting.
In particular, a folk theorem applies to such games. Thus, games of probabilistic cheap provide a third interpretation of
the repeated game framework with the additional feature that expected payoff is invariant to the probability of the game ending.
Received: 10 May 1999/Accepted: 16 October 2000 相似文献