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61.
姜志明 《石油化工管理干部学院学报》2003,(4):61-62
从辩证关系角度详细阐述了类似于北京燕化建筑工程公司这样的国有施工企业走向市场过程中应关注的企业定位、利益相关性、竞争策略与公平性、自我保护与內涵发展等问题,以促进国有施工企业的改革与发展。 相似文献
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A function minimization algorithm that updates solutions based on approximated derivative information is proposed. The algorithm generates sample points with Gaussian white noise, and approximates derivatives based on stochastic sensitivity analysis. Unlike standard trust region methods which calculate gradients with n or more sample points, where n is the number of variables, the proposed algorithm allows the number of sample points M to be less than n. Furthermore, it ignores small amounts of noise within a trust region. This paper addresses the following two questions: how does the derivative approximation become worse when the number of sample points is small? Can the algorithm find good solutions with inexact derivative information when the objective landscape is noisy? Through intensive numerical experiments using quadratic functions, the algorithm is shown to be able to approximate derivatives when M is about n/10 or more. The experiments using a formulation of the traveling salesman problem show that the algorithm can find reasonably good solutions for noisy objective landscapes with inexact derivatives information. 相似文献
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Fadwa T. Eljack Ahmed F. Abdelhady Mario R. Eden Frederico B. Gabriel Xiaoyun Qin Mahmoud M. El-Halwagi 《Computers & Chemical Engineering》2005,29(11-12):2304
Decoupling the constitutive equations from the balance and constraint equations allows for reformulating a conventional forward problem into two reverse problems. The first reverse problem is the reverse of a simulation problem, where the process model is solved in terms of the constitutive (synthesis/design) variables instead of the process variables, thus providing the synthesis/design targets. The second reverse problem (reverse property prediction) solves the constitutive equations to identify unit operations, operating conditions and/or products by matching the synthesis/design targets. Visualization of the problem is achieved by employing recently developed property clustering techniques, which allows a high-dimensional problem to be visualized in two or three dimensions. The clusters by definition satisfy intra-stream and inter-stream conservation through linear “mixing” rules, which allows for the development of consistent additive rules along with their ternary representation. 相似文献
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Children's perceived attachments with parents, and family cohesion and adaptability were examined as predictors, mediators, and moderators in the parental problem drinking-child outcomes link. A total of 216 6- to 12-year-olds (110 boys, 106 girls) participated. Data were obtained from children and their mothers, fathers, and teachers. A higher level of family cohesion and adaptability functioned as (a) a robust protective factor against adjustment and cognitive difficulties otherwise associated with problem drinking and (b) a mediator of adjustment problems. Children's perceptions of attachments to mothers and fathers were consistent predictors of behavioral, social, and cognitive problems and further moderated relations between problem drinking and child functioning. The results support that child-parent and family functioning variables act as either pathways and/or vulnerability and protective factors for children exposed to a high-risk environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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一个改进的单抓钩周期性排序模型及其在自动化学处理线中的应用 总被引:1,自引:0,他引:1
计算机控制的抓钩广泛用于自动化学处理线的工件的运送。抓钩的排序直接影响系统的生产率,抓钩排序的目标是对运送进行排序以极大化生产率。当某工序处理时间非常长时,该工序成为瓶颈。为了去除该瓶颈,系统可以为该工序设计多个处理槽,这称为“多重处理槽”问题。本文提出一个改进的混合整数规划模型以求解有“多重处理槽”的单抓钩周期性排序问题的最优解。实例表明所提出的方法是有效的。 相似文献
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软件问题管理是软件测试的核心活动,也是软件测试管理的灵魂.探讨了软件问题管理的重要性,介绍了两种软件问题生命周期建模的基本模型,提出了一种包含子状态控制的状态可定制的改进的生命周期模型,最后基于提出的生命周期模型给出与其相应的建模方法. 相似文献
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