查询词典 discrete optimization

Optimization solution algorithm is the most important in topology optimization.Algorithms fit for discrete structure and continuum structure are all investigated. Thecharacteristic and different using limit of both optimization criteria method andmathematics programming method are all analyzed in this paper. OC algorithm and theseries MMA algorithm based on SIMP approach are deducedand used for the topology optimization problem of continuum structure.

优化求解算法是拓扑优化问题求解的核心和关键，本文系统分析了适用于离散结构和连续体结构优化的优化求解算法，重点讨论了 OC 算法和 MP 算法，分析比较了不同算法的特点和适用范围，推导了基于 SIMP 理论的优化准则法和 MMA 系列算法，并将MMA 系列算法应用于连续体结构拓扑优化问题的求解。

Based on the ICMmethod,the discrete topological optimization problem about spot-weld's existence or not is transformed into the continuous optimization problem on[0,1].The optimization model is founded with maximizing the structural stiffness as objective and structural strength as constraints.The problem of multi-objectives and multi-constraints is transformed into the problem of single-objective and single-constraint with the K-S function.The displacement and stress are transformed into the explicit function of design variables with the Response Surface Methodology.The optimization model is solved with Sequential Quadratic Program.

基于ICM（Independent Continuous Mapping，即独立、连续、映射）方法，将焊点有无的离散拓扑优化问题转化为[0，1]区间上的连续优化问题；建立了以结构刚度最大为目标、结构强度为约束的连续拓扑优化模型；采用K-S函数将多目标和多约束问题转化为单目标和单约束问题；运用响应面方法将位移和应力转化为设计变量的显式函数，采用序列二次规划方法求解优化模型。

In this paper an optimum design method complex method with mixed discrete variables is discussed with the focus on the optimization design of discrete and continuous variables.

针对工程中大量存在的设计变量为离散型和连续型的混合离散变量的情况，探讨了一种优化设计问题的方法———混合离散复合形法。

Mixed Discrete Complex Programming is a mature optimization recently . It is suitable for the questions containing discrete variable .But, its' astringency is slow and easy to be trapped in the partial solution .

离散变量复合型法是当前比较成熟的管道优化算法，适用于求解含离散变量的优化问题，但存在收敛速度缓慢、易陷入局部最优解的缺点。

Three solution algorithms for classical transportation continuous/discrete/ mixed network design problems are designed based on particle swarm optimization approach, in which the continuous NDP is studied in detail, discrete and mixed NDP are only described the frameworks of the solution algorithms.2. Generally, road capacity constraints must be added to the lower level problem of classical discrete NDPs bilevel programming model in order to avoid traffic assignment on candidate roads.

本论文研究工作主要有如下几个方面：(1)基于粒子群优化思想设计了求解传统的城市道路交通网络设计问题的算法，其中详细研究了连续网络设计问题，并用两个网络例子进行了数值实验；并给出了离散网络设计问题和混合网络设计问题的求解算法思路和主要步骤。

The dissertation focuses on performance gradient estimation and SRO algorithm of DES aswell as other related topics,such as modeling of DES and discrete event simulation,performancemeasure Hessian matrix estimation,Stochastic Approximationand so on.General Semi-Markov Processis adapted to describe behaviour of DES and discrete eventsimulation.A general result is obtained and applied to analyze strong consistency of performancegradient Perturbation Analysisestimator.Conditions for effectiveness of InfinitesimalPerturbation Analysisare also discussed.New PA algorithms,such as server PA,PA usingDirac generalized function,job sequence PA etc.,are proposed to deal with discreteparameters.Furthermore,strategies of combining PA algorithms with certain iterative rules areanalyzed widely in order to optimize DES parameters and some SRO algorithms are constructed toslove DES optimization problems.

论文将DES性能分析领域中性能梯度估计和单运行仿真优化作为主要的研究对象，探讨了与性能梯度估计有关的DES和离散事件仿真过程建模、高阶导数估计以及随机逼近等理论和方法；建立了具有一般性的DES和离散事件仿真的广义半Markov过程模型；获得了分析性能梯度估计量强相合性的理论结果和无穷小摄动分析算法应用的条件；提出了诸如服务台数目的摄动分析、奇异摄动分析、串联生产线和加工车间中工件加工序的摄动分析等一系列摄动的思想和算法，对连续参数和离散参数都进行了深入的研究；对摄动分析算法同优化规则结合实现仿真优化的策略也进行了广泛的分析，构造了新型的变界截尾的随机逼近算法，并用于DES的单运行仿真优化研究；最后，给出了DES性能分析方法的实证性研究结果。

The algorithm is proved to be convergent theoretically and implemented for numerical calculation.Thirdly, two kind problems of multi-unit system maintenance based on the discrete-state deterioration model are analyzed:To achieve the optimization aim of series system consist of two types of units with different failure mode, an opportunistic policy is presented to combine the corrective and condition-based maintenance. The optimal model based on this policy is built and an iteration algorithm based on sequential decision is proposed according to the characteristic of discrete-state deterioration model.

第三、在部件优化分析的基础上，针对基于离散状态劣化模型的多部件系统视情维修决策中的两类典型问题，提出了相应的机会维修策略和优化分析方法：(1)针对串联系统由分别采用视情维修和事后维修的两类部件组成的情况，提出了一类事后维修与视情维修相结合的机会策略，建立了相应的多部件系统维修优化模型，并根据离散状态劣化模型的特点，提出了一类基于序贯决策的求解方法。

By using the transfer matrix method of multibody system, the hard problem of computation of the vibration characteristics of LRMLRS coupled with rigid bodies and elastic bodies is solved which is very difficult to the ordinary dynamic methods, and the vibration characteristics of LRMLRS which is varied when the number of rockets in the launch device is varied, is obtained conveniently. By developing augmented eigenvectors of the LRMLRS and its orthogonality conditions, the nonorthogonality problem of the multibody system including rigid bodies and elastic bodies is solved and the exact analysis of the dynamics response of the LRMLRS including rigid bodies and elastic bodies is realized. By using the random integer programming method, the hard optimization problem which contains continuous variables, discrete variables and random variables at the same time is solved. This method provides a technology for optimum design with random variables and discrete variables. The dynamic optimum design is realized to decrease the number of rockets consumption in the LRMLRS test. The simulation system of dispersion of fire is established by using the maximum entropy method to estimate dispersion of fire.

通过应用多体系统传递矩阵法，解决了刚弹耦合远程多管火箭多体系统振动特性这一通常力学方法不便于解决的计算难题，方便地获得了远程多管火箭振动特性及其随发射架上火箭弹个数变化而变化的情况；通过构造增广特征矢量及其正交性条件，解决了刚弹耦合多体系统特征矢量不具有通常意义下的正交性的难题，实现了对刚弹耦合远程多管火箭动力响应的精确分析；应用随机整数规划法，解决了同时考虑连续、离散和随机变量等多种设计变量的优化设计难题，为含随机和离散变量的优化设计提供了手段，实现了减少远程多管火箭试验用弹量的动态优化设计；建立了应用最大熵法估计的密集度仿真系统，优化射序和射击间隔，实现了提高远程多管火箭射击密集度的动态优化。

Among them, one of the most promising seems to be Simulation Annealing that aims to reach the optimization of an objective function by physically analogizing to an annealing process of malerial at high temperature. This involves in a transformation of optimization of a function in continuous domain into a combinatorial optimization in discrete domain, as well as the proper choice of various control parameters such as temperature, iterative number etc.

为此，目前主要采用三种基于随机搜索策略的鲁棒技术，其中模拟退火算法是最有希望的一种，该算法的核心思想是随机模拟物理上的物质退火过程，它主要涉及将连续域优化问题转换为离散的组合优化问题，以及合理地选择各种控制参数、迭代时间等。

The application of genetic algorithm in optimization design of structures with discrete variables is presented with an example of optimization design for three-bar hyper static truss structures with discrete variables.

以三杆桁架结构优化设计演示了遗传算法在离散变量优化设计中的应用。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。