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1.
数学最优化技术在过程系统综合中起着重要作用。本文综述了混合整数非线性规划(MINLP)和随机优化两类最优化方法在多组分精馏过程综合中的应用及取得的新成果。首先对离散流程结构的表达方法、MINLP模型的建立和求解方法、以及各种方法的优缺点等方面进行了比较分析;随后提出了一种新的可包括复杂精馏结构的编码表达法及一个求解混合变量问题的随机优化策略;最后对该领域发展提出展望。  相似文献   

2.
针对传统的离散事件系统仿真技术在排队系统进行设计方面存在的不足和困难,本文提出采 用一种新的仿真技术——离散事件系统逆向仿真来解决,并以单急救站系统为例,介绍了逆向 仿真应用于该系统进行结构设计的具体方法和过程,最后通过正向仿真对设计结果进行检验, 说明了利用逆向仿真求解该类问题的可行性和有效性.  相似文献   

3.
多选择背包问题离散狼群算法研究   总被引:1,自引:0,他引:1  
狼群算法是一种通过模拟狼群的捕食行为和猎物分配方式提出的群体智能算法,为求解复杂组合优化问题提供了一种新的思路。目前狼群算法不能解决离散问题,以NP难中的经典问题——多选择背包问题的求解为研究对象,设计了基于离散空间的狼群算法。对于离散空间的狼群算法,通过将人工狼编码,重新设计了狼群的游走、奔袭和围捕过程,并设计了三个过程中的步长。把学习机制引入离散狼群算法,实现了人工狼之间的交流,且确立了自适应步长公式。结果表明:离散狼群算法成功实现了对离散问题的求解,为组合优化问题的求解提供了新方法。  相似文献   

4.
对于桥式吊车系统的最优控制问题,根据实际的工况要求,性能指标有时不一定是标准的二次形式.同时,在实际的控制问题中,状态和控制输入往往会受到一些边界条件和路径过程中的约束.针对这一问题,本文应用Chebyshev伪谱优化算法来处理,它可以处理状态和控制约束的非线性最优化问题以及一个非标准的目标函数.首先对桥式吊车系统模型进行一系列的坐标变换,将其转变为上三角系统形式的误差模型.然后将桥式吊车最优控制问题转化成具有一系列代数约束的参数优化问题,即非线性规划问题.通过求解离散化后的参数优化问题,得到桥式吊车的最优控制律.本文还给出了Chebyshev伪谱最优解的可行性和一致性分析.最后,在仿真研究中验证该控制器的有效性.  相似文献   

5.
离散灰色模型的仿射特性研究   总被引:3,自引:1,他引:2  
对离散灰色模型进行了重新定义并给出了参数求解式,建立了离散最优化灰色模型.通过对这两个模型进行仿射特性研究,分析了仿射变换导致的模型参数变化特征,以及仿射变换对模型模拟和预测值的影响.研究结果表明,通过仿射变换,可以缩小数据的量级,简化建模过程,而不会改变模型的模拟和预测效果.  相似文献   

6.
一种具有混合编码的二进制差分演化算法   总被引:11,自引:0,他引:11  
差分演化(DE)是Storn和Price于1997年提出的一种基于个体差异重组思想的演化算法,非常适用于求解连续域上的最优化问题.首先引入"差异算子"等概念,给出DE的一种简洁算法描述,并分析了它所具有的特性.然后,为了使DE能够求解离散域上的最优化问题,基于数学变换思想引入"辅助搜索空间"和"个体混合编码"等概念,通过定义一个特殊的满射变换,在辅助搜索空间的作用下将连续域上的高效差分演化搜索变换为离散域上的同步演化搜索,由此提出了第1个二进制差分演化算法:具有混合编码的二进制差分演化算法(HBDE).接着,给出了HBDE的依概率收敛和完全收敛的定义,并利用离散Markov随机理论证明了HBDE是完全收敛的. HBDE不仅完全具有DE的各种特性和所有优点,而且非常适用于求解离散域上的最优化问题,对随机生成的大规模3-SAT问题实例和典型0/1背包问题实例的数值计算表明:该算法具有很好的全局收敛性和稳定性,其性能远远超过二进制粒子群优化算法和遗传算法.  相似文献   

7.
板坯加热炉的递阶计算机控制   总被引:2,自引:0,他引:2  
本文以作者开发的板坯加热炉离散状态空间模型为基础提出了以启发式搜索方法求解加热炉炉温设定值最优化问题的原理,并介绍了基于上述原理的加热炉递阶计算机控制系统的设计与实施.该系统经过一年多连续运行表明其控制准确、性能可靠,降低能耗9%,明显提高钢坯的加热质量,直接经济效益可达100万元/年以上.  相似文献   

8.
用于间歇化工过程最优设计的遗传算法   总被引:6,自引:0,他引:6  
间歇化工过程的最优设计问题是一类复杂且难以求解的组合优化问题。通过把这类问题分解为只包含离散变量的主导问题和只含连续变量的子问题,把遗传算法和线性规划法结合起来对其进行求解。并在算法中引入了一类新的算子,显著地提高了收敛概率、算例表明,该方法可以避免直接求解过程的复杂性和困难,并且具有很好的全局收敛性。  相似文献   

9.
采用一种新的混合标识过程/变迁网模型一变计时过程/变迁网来描述复杂工业过程。该模型通过引入过程运行标志离散标识(逻辑变量)和过程运行剩余时间连续标识(时间变量),有效解决了多工位多工况复杂工业过程底层子过程的集成建模问题、离散事件与连续状态和过程控制与生产控制之间的耦合衔接问题,以及离散事件实时监控、连续子过程实时调度与控制等问题。给出了其实时监控、实时调度与过程控制的最佳策略求解方法。  相似文献   

10.
间歇化工过程的最优设计问题是一类复杂且难以求解的组合优化问题。通过把这类问题分解为只包含离散变量的主导问题和只含连续变量的子问题,把遗传算法和线性规划法结合起来对其进行求解。并在算法中引入了一类新的算子,显著地提高了收敛概率。算例表明,该方法可以避免直接求解过程的复杂性和困难,并且具有很好的全局收敛性。  相似文献   

11.
《Advanced Robotics》2013,27(3):319-333
This paper describes a new algorithm for analysing the influence of the tool geometry on the motions of industrial robots in large manufacturing systems. On the basis of given points which are defined by the periphery devices used, the proposed method allows an evaluation of the cycle time. The computational time which is needed to determine the robot trajectory is kept small because an approach with constant velocities is calculated instead of the real path. In addition to an analysis of a single motion between two points, it is possible to calculate values for motions between several points which are linked together by a point to point move, so that an optimization of complex processes can be reached.  相似文献   

12.
This paper describes a multi-agent architecture based on the actors computational model, for the distributed simulation of discrete event systems whose entities have a complex dynamic behaviour. Complexity is dealt with by exploiting statechart-based actors which constitute the basic building blocks of a model. Actors are lightweight reactive autonomous agents that communicate to one another by asynchronous message passing. The thread-less character of actors saves memory space and fosters efficient execution. The behaviour of actors is specified through “distilled statecharts” that enable hierarchical and modular specifications. Distributed simulation is achieved by partitioning a system model among a set of logical processes (theatres). Timing management and inter-theatre communications rest in a case on the High Level Architecture services. The paper illustrates the practical application of the proposed modelling and simulation methodology by specifying and analysing a complex manufacturing system.  相似文献   

13.
电力系统无功优化问题是一个多变量、多约束的混合非线性规划问题,其操作变量既有连续变量又有离散变量,其优化过程比较复杂。遗传算法是模拟生物在自然环境中的遗传和进化过程而形成的一种自适应的全局优化搜索算法,可用于解决含有离散变量的复杂优化问题。本文选用遗传算法求解电力系统无功优化问题,并对基本遗传算法的编码、初始种群、适应度函数和交叉、变异策略等进行改进,使用本文提出的改进算法对IEEE1 4节点进行无功优化计算,结果证明本文模型和算法的实用性、可靠性和优越性。  相似文献   

14.
基于可拓控制的离散变结构系统的组合控制   总被引:1,自引:0,他引:1  
刁晨  陈希平 《计算机仿真》2007,24(2):130-133
提出了一种新的离散变结构系统组合控制策略和一种改进的变速趋近律.众所周知,由于变结构控制系统中存在高频抖振,这一现象限制了变结构控制方法在各种工程设计领域中的应用.新的离散变结构系统组合控制策略的目的是使系统在最短的时间内完成正常运动从而系统的鲁棒性得以提高.对于滑动模态的到达问题,提出了基于改进的变速趋近率、指数趋近率和可拓控制的组合控制策略.这种新的控制策略能有效地削弱抖振提高系统的动态性能.最后通过将传统组合控制策略与所提出的组合控制策略仿真比较,其结果表明新的组合控制策略能够获得令人满意的结果.  相似文献   

15.
Ant Algorithms: Theory and Applications   总被引:6,自引:0,他引:6  
This paper reviews the theory and applications of ant algorithms, new methods of discrete optimization based on the simulation of self-organized colony of biologic ants. The colony can be regarded as a multi-agent system where each agent is functioning independently by simple rules. Unlike the nearly primitive behavior of the agents, the behavior of the whole system happens to be amazingly reasonable. The ant algorithms have been extensively studied by European researchers from the mid-1990s. These algorithms have successfully been applied to solving many complex combinatorial optimization problems, such as the traveling salesman problem, the vehicle routing problem, the problem of graph coloring, the quadratic assignment problem, the problem of network-traffic optimization, the job-shop scheduling problem, etc. The ant algorithms are especially efficient for online optimization of processes in distributed nonstationary systems (for example, telecommunication network routing).__________Translated from Programmirovanie, Vol. 31, No. 4, 2005.Original Russian Text Copyright © 2005 by Shtovba.  相似文献   

16.
离散非线性系统开闭环P型迭代学习控制律及其收敛性   总被引:9,自引:3,他引:9  
本文在讨论了一般开环与闭环迭代学习控制的不足后,针对一类离散非线性系统,提出了新的开闭环PG型迭代学习控制律,给出了它的收敛性证明,仿真结果表明:开闭环P型迭代律优于单纯的开环或产才环P型迭代 律。  相似文献   

17.
在网格计算中,资源的调度优化特别是请求的调度优化是一个关键技术问题,引入离散事件动态系统中的水箱型混合动态系统模型,对网格上的资源和请求进行一体化建模。清空型调度策略是混合动态系统中一类重要的调度策略,研究了它在网格环境下的应用性能,提出一种推广形式。重点研究系统模型的建立和调度策略的稳定性分析,给出稳定性证明的理论推导过程和仿真实验结果。为下一代网络中的数据管理提供了一种新思路。  相似文献   

18.
We propose a new method for laminate stacking sequence optimization based on a two-level approximation and genetic algorithm (GA), and establish an optimization model including continuous size variables (thicknesses of plies) and discrete variables (0/1 variables that represent the existence of each ply). To solve this problem, a first-level approximate problem is constructed using the branched multipoint approximate (BMA) function. Since mixed-variables are involved in the first-level approximate problem, a new optimization strategy is introduced. The discrete variables are optimized through the GA. When calculating the fitness of each member in the population of GA, a second-level approximate problem that can be solved by the dual method is established to obtain the optimal thicknesses corresponding to the each given ply orientation sequence. The two-level approximation genetic algorithm optimization is performed starting from a ground laminate structure, which could include relatively arbitrarily discrete set of angles. The method is first applied to cylindrical laminate design examples to demonstrate its efficiency and accuracy compared with known methods. The capacity of the optimization strategy to solve more complex problems is then demonstrated using a design example. With the presented method, the stacking sequence in analytical tools can be directly taken as design variables and no intermediate variables need be adopted.  相似文献   

19.
Job Shop Scheduling Problem (JSSP) is one of classic combinatorial optimization problems and has a long research history. Modern job shop has following characteristics: increasingly complicated processes, small batch and personalized requirement, which lead to complex correlations among processes. Complex correlations of processes, involving nested correlations besides serial and parallel correlations, propose a new task for JSSP research. Decomposing JSSP into two nested sub problems of order of arranging processes and machine arrangement, this research integrates the traditional thought of complex method into the ant colony optimization (ACO) to develop a nested optimization method in order to solve the new task. This paper is divided into four parts: first, the model of JSSP with complex associated processes is constructed and the difficulties to solve which are analyzed and listed; second, the definition of “order of arranging processes” is originally proposed, based on which the mathematical model available for the complex method is developed, taking process starting time as design variables of the first level optimization. The steps of the first level optimization and the secondary nested flow chart are detailed with the demonstration of the effectiveness of the complex method’s iteration mechanism; third, based on the representation of features the order of arranging processes obtained by the first level optimization combined with the first-in first-out rule owns, the corresponding modified ACO algorithm, involving pheromone positive perception and reverse spreading mechanism, is put forward to realize the second level optimization, which result is taken as the objective function value of the complex vertex to realize the secondary nested optimization strategy; finally, taking plentiful JSSP with complex associated processes as study cases, a serial of comparative experiments are done respectively adopting the genetic algorithm, ACO algorithm, particle swarm optimization algorithm, some combinations of heuristic algorithms respectively in the nested two levels, and the proposed nested optimization method, and experiment results attest the reliability and superiority of the proposed method.  相似文献   

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