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排序方式: 共有438条查询结果,搜索用时 187 毫秒
61.
62.
资源约束型项目调度的优化是一个NP-hard问题,其求解难度随着资源约束项的增多呈指数方式增长,传统的基于Excel表的手工优化方法不能及时计算出有效的资源配置方式,从而影响项目管理人员的资源调度.针对多资源约束型项目调度的优化问题提出基于遗传算法的资源约束型项目调度的优化方法,该算法采用基于活动优先权的十进制编码方式,结合活动的存储邻接矩阵,有效地解决活动调度违例现象;运用优先抢占模式的资源分配方式安排活动资源,避免资源分配中的冲突问题;并为该算法设计了启发式遗传算法的C语言程序,通过计算机的多次迭代运算得出满足资源约束的最优工期.实践结果表明,遗传算法可以快速有效地解决企业项目调度的优化问题,适合在企业项目进度管理中推广运用. 相似文献
63.
Morgan A. Bishop Anthony J. Macula Thomas E. Renz Vladimir V. Ufimtsev 《Journal of Combinatorial Optimization》2008,15(1):7-16
Classical group testing (CGT) is a widely applicable biotechnical technique used to identify a small number of distinguished
objects from a population when the presence of any one of these distinguished objects among a group of others produces an observable result. This paper discusses a variant of CGT called group testing for disjoint pairs (GTAP). The difference between the two is that in GTDP, the distinguished items are pairs from, not individual objects in,
the population. There are several biological examples of when this abstract model applies. One biological example is DNA hybridization.
The presence of pairs of hybridized DNA strands can be detected in a pool of DNA strands. Another situation is the detection
of binding interactions between prey and bait proteins. This paper gives a random pooling method, similar in spirit to hypothesis
testing, which identifies pairs of objects from a population that collectively have an observable function. This method is
simply to apply, achieves good results, is amenable to automation and can be easily modified to compensate for testing errors.
M.A. Bishop is supported by AFOSR FA8750-06-C-0007.
A.J. Macula is supported by NSF-0436298, AFOSR FA8750-06-C-0007. 相似文献
64.
Group testing, sometimes called pooling design, has been applied to a variety of problems such as blood testing, multiple
access communication, coding theory, among others. Recently, screening experiments in molecular biology has become the most
important application. In this paper, we review several models in this application by focusing on decoding, namely, giving
a comparative study of how the problem is solved in each of these models. 相似文献
65.
Manuel Rizzo Francesco Battaglia 《Journal of Statistical Computation and Simulation》2018,88(16):3081-3097
When a genetic algorithm (GA) is employed in a statistical problem, the result is affected by both variability due to sampling and the stochastic elements of algorithm. Both of these components should be controlled in order to obtain reliable results. In the present work we analyze parametric estimation problems tackled by GAs, and pursue two objectives: the first one is related to a formal variability analysis of final estimates, showing that it can be easily decomposed in the two sources of variability. In the second one we introduce a framework of GA estimation with fixed computational resources, which is a form of statistical and the computational tradeoff question, crucial in recent problems. In this situation the result should be optimal from both the statistical and computational point of view, considering the two sources of variability and the constraints on resources. Simulation studies will be presented for illustrating the proposed method and the statistical and computational tradeoff question. 相似文献
66.
多维背包问题的二进制蚂蚁算法 总被引:1,自引:0,他引:1
针对著名的多维背包问题(MKP), 在蚁群优化系统高维立方体结构的基础上,提出了一种二进制蚂蚁算法(BAS).与其他求解MKP问题的蚂蚁算法不同,BAS根据二进制解的结构设计了特殊的信息素放置方式,同时在算法的迭代过程中允许非可行解的产生,并通过基于问题特征信息的修改算子修复每次迭代所产生的非可行解.BAS算法采用了特殊的信息素更新规则,使得各个选择路径上的信息素可以直接作为选择概率,同时,为了避免算法陷入早熟,BAS设计了简单的局部搜索法,并根据算法所处的不同收敛状况,采用了不同的信息素更新规划和信息素重新初始化的方法.针对MKP基准问题的实验结果表明,BAS具有超越其他蚂蚁算法的求解结果,其求解不同基准测试问题的能力表明了BAS具有解决超大规模MKP问题的潜力. 相似文献
67.
An improved approximation algorithm for uncapacitated facility location problem with penalties 总被引:1,自引:0,他引:1
In this paper, we consider an interesting variant of the classical facility location problem called uncapacitated facility location problem with penalties (UFLWP for short) in which each client is either assigned to an opened facility or rejected by paying a penalty. The UFLWP
problem has been effectively used to model the facility location problem with outliers. Three constant approximation algorithms
have been obtained (Charikar et al. in Proceedings of the Symposium on Discrete Algorithms, pp. 642–651, 2001; Jain et al. in J. ACM 50(6):795–824, 2003; Xu and Xu in Inf. Process. Lett. 94(3):119–123, 2005), and the best known performance ratio is 2. The only known hardness result is a 1.463-inapproximability result inherited
from the uncapacitated facility location problem (Guha and Khuller in J. Algorithms 31(1):228–248, 1999). In this paper, We present a 1.8526-approximation algorithm for the UFLWP problem. Our algorithm significantly reduces the
gap between known performance ratio and the inapproximability result. Our algorithm first enhances the primal-dual method
for the UFLWP problem (Charikar et al. in Proceedings of the Symposium on Discrete Algorithms, pp. 642–651, 2001) so that outliers can be recognized more efficiently, and then applies a local search heuristic (Charikar and Guha in Proceedings
of the 39th IEEE Symposium on Foundations of Computer Science, pp. 378–388, 1999) to further reduce the cost for serving those non-rejected clients. Our algorithm is simple and can be easily implemented.
The research of this work was supported in part by NSF through CAREER award CCF-0546509 and grant IIS-0713489. A preliminary
version of this paper appeared in the Proceedings of the 11th Annual International Computing and Combinatorics Conference
(COCOON’05). 相似文献
68.
How does granting certificates of ‘business clean of Arab workers’ to owners of shops, stores, and Jewish businesses who prove they are not employing Arab workers shape identity? Identity development involves making sense of, and coming to terms with, the social world one inhabits, recognizing choices and making decisions within contexts, and finding a sense of unity within one's self while claiming a place in the world. Since there is no objective, ahistoric, universal trans-cultural identity, views of identity must be historically and culturally situated. This paper explores identity issues among members of the Palestinian Arab minority in Israel. While there is a body of literature exploring this subject, we will offer a different perspective by contextualizing the political and economic contexts that form an essential foundation for understanding identity formation among this minority group. We argue that, as a genre of settler colonialism, ‘pure settlement colonies’ involve the conquering not only of land, but of labor as well, excluding the natives from the economy. Such an exclusion from the economy is significant for its cultural, social, and ideological consequences, and therefore is especially significant in identity formation discussed in the paper. We briefly review existing approaches to the study of identity among Palestinian Arabs in Israel, and illustrate our theoretical contextual framework. Finally, we present and discuss findings from a new study of identity among Palestinian Arab college students in Israel through the lens of this framework. 相似文献
69.
70.