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51.
M. Stolpe K. Svanberg 《International journal for numerical methods in engineering》2003,57(5):723-739
This paper deals with topology optimization of discretized continuum structures. It is shown that a large class of non‐linear 0–1 topology optimization problems, including stress‐ and displacement‐constrained minimum weight problems, can equivalently be modelled as linear mixed 0–1 programs. The modelling approach is applied to some test problems which are solved to global optimality. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
52.
本文对多目标二次规划问题非劣解集的理论生成进行了探讨,在介绍二次规划单目标问题优化解求法的基础上,提出了在决策平面上互切点,共交点轨迹的概念.由此导出了非劣解集的一般解析式(对切点解问题)和另一类交点解问题时的非劣解集求法,然后介绍了在目标平面非劣解集的解析表达式.使多目标二次规划问题整个非劣解集的推求严格、明确和方便,有理论和实际意义。文中以一个综合利用水库参数的多目标优选作为例子阐述了应用,并求出了最终的最佳协调解. 相似文献
53.
Scheduling emergency medicine residents (EMRs) is a complex task, which considers a large number of rules (often conflicting) related to various aspects such as limits on the number of consecutive work hours, number of day and night shifts that should be worked by each resident, resident staffing requirements according to seniority levels for the day and night shifts, restrictions on the number of consecutive day and night shifts assigned, vacation periods, weekend off requests, and fair distribution of responsibilities among the residents. Emergency rooms (ERs) are stressful workplaces, and in addition shift work is well-known to be more demanding than regular daytime work. For this reason, preparing schedules that suit the working rules for EMRs is especially important for reducing the negative impact on shift workers physiologically, psychologically, and socially. In this paper, we present a goal programming (GP) model that accommodates both hard and soft constraints for a monthly planning horizon. The hard constraints should be adhered to strictly, whereas the soft constraints can be violated when necessary. The relative importance values of the soft constraints have been computed by the analytical hierarchy process (AHP), which are used as coefficients of the deviations from the soft constraints in the objective function. The model has been tested in the ER of a major local university hospital. The main conclusions of the study are that problems of realistic size can be solved quickly and the generated schedules have very high qualities compared to the manually prepared schedules, which require a lot of effort and time from the chief resident who is responsible for this duty. 相似文献
54.
本文给出一个结构不完全对称并联电网的等价定理,它把双输入双输出非线性耦合的微分方程组等价为单输入单输出的非线性微分方程,然后用渐近方法和谐波线性化方法求其一次近似解,得到一些新的物理性质,有助于合理选择电网结构,以提高其结构稳定性. 相似文献
55.
价格不确定情况下炼厂生产计划的优化 总被引:4,自引:0,他引:4
生产计划的编制是炼油企业生产经营管理中的一个关键环节,然而由于市场变化的不确定性,使企业制度长远规划受到限制,笔者将多目标规划应用于炼厂价格不确定情况下生产计划的制定,使所得到的生产计划在一定程度上反映市场的变化并能使企业的生产效益最优,为企业管理决策者进行长远规划给予指导。通过实例验证了该方法的可行性。 相似文献
56.
Optimal Operation of Reservoir Systems using Simulated Annealing 总被引:5,自引:0,他引:5
A stochastic search technique, simulated annealing (SA), is used to optimize the operation of multiple reservoirs. Seminal application of annealing technique in general to multi-period, multiple-reservoir systems, along with problem representation and selection of different parameter values used in the annealing algorithm for specific cases is discussed. The search technique is improved with the help of heuristic rules, problem-specific information and concepts from the field of evolutionary algorithms. The technique is tested for application to a benchmark problem of four-reservoir system previously solved using a linear programming formulation and its ability to replicate the global optimum solution is examined. The technique is also applied to a system of four hydropower generating reservoirs in Manitoba, Canada, to derive optimal operating rules. A limited version of this problem is solved using a mixed integer nonlinear programming and results are compared with those obtained using SA. A better objective function value is obtained using simulated annealing than the value from a mixed integer non-linear programming model developed for the same problem. Results obtained from these applications suggest that simulated annealing can be used for obtaining near-optimal solutions for multi-period reservoir operation problems that are computationally intractable. 相似文献
57.
空间桁架结构拓扑优化设计的线性规划方法 总被引:1,自引:0,他引:1
本文以杆件内力为设计变量,构造了多工况作用下空间桁架结构拓扑优化的线性规划模型,考虑了应力和位移约束,能够避免奇异最优拓扑和不稳定结构的产生。 相似文献
58.
Yasuhiro Kobayashi Toshiyuki Sawa Toshiyuki Furukawa Shigeru Kawamoto 《Electrical Engineering in Japan》2002,138(2):49-58
This paper describes a load dispatch method which minimizes power cost—[fuel cost]/[electric output]—for a power system with thermal plants and energy storage facilities. The proposed method employs fractional programming to convert a minimization problem with fractional objective function to a series of quadratic minimization problems, and semidefinite programming to solve converted problems. The method provides the optimum time‐dependent power output/input and storage level of energy storage facilities as well as time‐dependent power output of thermal plants. The method has been applied to a power system with five thermal plants, two energy storage facilities of various performances, and five load demands. The optimum load scheme of four time mesh points is obtained for the thermal plants and energy storage facilities. The fractional programming successfully converges the optimal scheme through a few iterations. The semidefinite programming deals with a variable matrix of 164 dimensions, and 185 inequality constraints. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 49–58, 2002 相似文献
59.
转子系统热膨胀状态下固有横振频率 总被引:8,自引:3,他引:5
把转子的惯性力看成作用在轴上的外力,采用新的非线性渐近法研究热膨胀对转子系统固有横振频率的影响. 相似文献
60.