具有阻塞影响的柔性制造系统排队网络模型

用有限容量局部库区的开排队网络模拟柔性制造系统，模型中，机床加工工件的时间服从指数分布，运送台车按照静态Ｍａｒｋｏｖ方式运送工件且运送时间服从指数分布，被阻塞的工件按照ＢＡＲ机理被处理，静态Ｍａｒｋｏｖ工件运送方式中的概率值受工件被阻塞的影响。     

软计算求解并行多机成组工件调度问题

自从Zade将模糊理论引入求解组合优化问题以来，出现了很多基于模糊规则与智能优化算法相结合的软计算方法，文章尝试将这种方法用于解决并行多机成组工件flow-time问题，本问题中，设有n个工件计划在M台并行一致的机器上加工，这n个工作根据相似性分为b组，开始加工时，需要一个准备时间，当工件接续在同组工件之后加工时，不需要准备时间，反之，接续在不同组工件之后加工时，需要一个准备时间，本问题的目标是找到一个工件加工的调度顺序序列，使M台机器总的流水时间最小，在文章中，作者首次利用模糊规则量化结合遗传算法的软计算方法求解这类复杂的组合优化问题，最后给出计算实例及仿真结果。     

具有时间窗口约束的并行机床调度问题研究

具有时间窗口约束的并行机床调度问题可以被描述为在M台互不相同机器上安排加工N个工件。每个工件只能在一个给定机器子集中的一台机器上加工，且加工过程只能在给定的离散时间窗口内进行，并且工件的加工时间长度和时间窗口约束与加工机器有关。为了解决该问题，本文给出一种集成约束规划与禁忌搜索的搜索算法，其中约束规划系统被作为验证解的可行性和确定变量的值，而禁忌搜索过程被用来对解空间进行搜索。讨论禁忌搜索过程中的初始解产生、邻域结构、禁忌列表、解空间搜索等算法设计问题。最后给出算法在不同问题实例上的算法效率比较及分析。     

具有优势机器和恶化工件的流水作业排序问题

针对流水作业排序问题,建立了具有优势机器和恶化工件并且有无空闲限制的排序模型.在该排序模型中,机器加工工件时,工件的相邻加工工序之间不允许出现空闲,工件的加工时间是其开工时间的严格增加线性函数.其中讨论的优势机器有2种情况:机器形成增减增优势关系和机器形成减增减优势关系.考虑了多台机器的流水作业排序问题,其中,目标函数分别为极小化最大完工时间和极小化总完工时间,对于这两类问题分别给出了求解最优排序的多项式算法和它们的计算复杂性,并通过证明证实了算法的有效性.     

带有学习效应和机器可用性限制的排序问题

针对单机和两台机器的平行机排序问题,建立了机器具有学习效应和可用性限制的排序模型。在这个模型中,机器具有学习效应。在学习效应下,工件的加工时间与所排位置有关,对于需要在同台机器上加工的工件,工件随位置的靠后其实际的加工时间减少。同时由于定期维修等原因而导致机器在某段时间内不能加工工件。考虑了目标函数为极小化总完工时间的单机和两台机器的平行机问题。对于机器在任意时间进行维修的一般情况给出了动态规划算法,通过数值例子说明了算法的有效性,对机器在使用前进行维修的特殊情况给出了多项式算法。     

基于改进DP算法的具有优先序的变速机最小化成本调度

研究了工件具有任意标准优先序、一台机器在同一时间只可加工一个工件、最小化工件加工成本与机器使用成本之和的变速机调度问题.为该问题建立了DP模型,通过启发式规则和常规动态规划方法相结合、引入工件完工时间界限并保存每一步函数值,得到改进的DP算法,数值实验显示该算法具有较强的寻优能力和稳定性.     

交货期窗口下的并行机调度问题的遗传算法

给出了一种求解不同交货期窗口的并行机调度问题的混合遗传算法，根据问题的特征采用扩展排列编码方式表示工件的分配和排列，利用给出的调度优先级规则和最好适应值规则相结合的启发式算法对每台机器上工件的顺序进行调整，实验表明所给的算法是有效的。     

具有学习效应的平行机排序问题

针对具有学习效应的平行机排序模型,讨论了两类问题。在这一模型中,工件的实际加工时间不仅与其所在排序中的位置有关并且与其本身的学习率有关,对于在同一台机器上加工的工件,工件随位置的靠后其实际的加工时间减少。第1类问题的目标函数是极小化提前与延误的加权和;第2类问题的目标函数是极小化提前与误工工件数的加权和。对这两类问题分别给出了多项式算法。     

交货期服从指数分布的单机随机调度问题

工件完成时间与交货期差的绝对值加权和最小化单机随机调度问题是JIT（just-in-time)生产环境下的典型调度模型，是NP－hard问题，然而，当工件权值与加工时间成正比时，LPT（largest processing time）工件调度是问题的最优解，讨论了该问题加工时间和交货期都为随机变量，其中交货期服从指数分布，且工件权值与加工时间成正比的情形，给出了问题的最优解，并在一定条件下将结果推广到机器随机故障的情形。     

可变信息标志诱导下的路径选择行为

随着智能交通技术的发展,可变信息标志(VMS)被广泛应用于动态交通管理中.元胞传输模型(CTM)可以很好的模拟交通流激波、排队形成与消散等交通流动力学特性.应用CTM研究了无信息诱导路径选择、基于VMS的近视转换和有界理性路径选择等三种规则,数值模拟结果表明, 后两种规则可以减少系统 总出行时间,信息服从率越高, 系统的改善程度越大.当有界理性规则的``界'参数设置在一定区间内时,该规则优于近视转换规则, 否则不如近视转换规则.     

Reliability Analysis of a Cold Standby Repairable System with Repairman Extra Work

This paper deals with a cold standby repairable system with two identical units and one repairman who can do extra work in idle time. The authors are devoted to studying the unique existence and exponential stability of the system solution. C0-semigroup theory is used to prove the existence of a unique nonnegative time-dependent solution of the system. Then by using the theory of resolvent positive operator, the authors derive that dynamic solution of the system exponentially converges to its steady-state one which is the eigenfunction corresponding to eigenvalue 0 of the system operator. Some reliability indices of the system are discussed with a different method from traditional one. The authors also make a profit analysis to determine the optimal service time outside the system to maximize the system profit.     

针对FJSP的新型邻域搜索算法及其应用

针对柔性作业车间调度问题提出两种新颖的邻域搜索方法：极值优化邻域和扩展的关键块邻域,并将其结合形成搜索范围广、寻优能力强的复合邻域;以复合邻域为基础,构造改进的遗传算法,使之兼具广阔的全局搜索能力和深刻的局部搜索能力。另外,算法采用较新颖的两级编码方式,使得对于工序排序编码和机器分配编码两部分可采用相同或相近的遗传算子进行运算,提高运算效率。对算例的测试结果及与其他算法的比较验证了本文算法的有效性。     

The Effect of Worker Learning on Scheduling Jobs in a Hybrid Flow Shop: A Bi-Objective Approach

This paper studies learning effect as a resource utilization technique that can model improvement in worker’s ability as a result of repeating similar tasks. By considering learning of workers while performing setup times, a schedule can be determined to place jobs that share similar tools and fixtures next to each other. The purpose of this paper is to schedule a set of jobs in a hybrid flow shop (HFS) environment with learning effect while minimizing two objectives that are in conflict: namely maximum completion time (makespan) and total tardiness. Minimizing makespan is desirable from an internal efficiency viewpoint, but may result in individual jobs being scheduled past their due date, causing customer dissatisfaction and penalty costs. A bi-objective mixed integer programming model is developed, and the complexity of the developed bi-objective model is compared against the bi-criteria one through numerical examples. The effect of worker learning on the structure of assigned jobs to machines and their sequences is analyzed. Two solution methods based on the hybrid water flow like algorithm and non-dominated sorting and ranking concepts are proposed to solve the problem. The quality of the approximated sets of Pareto solutions is evaluated using several performance criteria. The results show that the proposed algorithms with learning effect perform well in reducing setup times and eliminate the need for setups itself through proper scheduling.     

极小化加权总完工时间的同时加工排序问题

讨论了平行机串联工件同时加工排序问题。目标函数是极小化加权总完工时间,并假设满足每批均含有k个工件,并且每批的加工时间为该批中所有工件的加工时间之和。对平行机的情况,该问题是强NP难的。本文主要针对该问题的两种特殊情况:(1)所有工件的权相等;(2)所有工件的加工时间相等,分别给出了最优算法,分析了算法的时间复杂性,同时用数值例子作了说明。     

Regional container port competition in a dual gateway-port system

Many ocean transportation hub systems consist of two container ports that share the container handling business in the area. The container flow passing through a port is the main measurement of the port’s competitiveness. In this paper we adopt a Hotelling model to study the container port competition in a so-called “dual gateway-port system”. The system contains two ports and two terminals, one belonging to each port. The two governments in which the two ports are located compete on cargo fees and the two terminals determine service price and service quality. We study two models with different levels of competition between the terminals. In the first model, the two terminals are owned by two different operators and in the second model, the two terminals are centralized under one operator. The second model exists in practice but is not well studied in the literature. We derive the cargo fee, terminal service price, and service quality equilibria for these two models. We investigate the competition outcome sensitivity with a numerical study. The numerical results reveal that governments prefer terminals to compete with each other. If the terminals do not have competitive advantages in their service quality, then terminal centralization brings more profits to the terminal operator than the competition case.     

一类可修的人机系统解的渐近稳定性

研究了两相同部件温储备可修的人机系统,利用由该系统所决定的算子A+B生成的Banach空间中的正压缩C0半群,证明了此系统的非负稳定解恰是算子A+B的.本征值对应的本征向量,同时通过研究算子A+B的谱特征,得到了算子A+B的谱点均位于复平面的左半平面且在虚轴上除0点外无谱的结论,进而得到了该系统的渐近稳定性.     

切削加工仿真建模技术研究

切削加工仿真是计算机仿真技术在机械制造业的重要应用领域之一。该技术对减少制造成本、缩短产品制造周期和提高产品质量意义重大。仿真模型的建立是实现切削加工仿真的关键环节，也是评价仿真系统优劣的重要指标之一。目前存在的切削加工仿真建模方法主要有三种：解析法、有限元法和分子动力学法。重点介绍了上述建模方法的实现原理和发展现状，并对其优缺点和适用范围加以评述。在此基础上，对切削加工仿真建模技术发展趋势做了进一步探讨。     

Real coded genetic algorithm for stochastic hydrothermal generation scheduling

The intent of this paper is to schedule short-term hydrothermal system probabilistically considering stochastic operating cost curves for thermal power generation units and uncertainties in load demand and reservoir water inflows. Therefore, the stochastic multi-objective hydrothermal generation scheduling problem is formulated with explicit recognition of uncertainties in the system production cost coefficients and system load, which are treated as random variable. Fuzzy methodology has been exploited for solving a decision making problem involving multiplicity of objectives and selection criterion for best compromised solution. A real-coded genetic algorithm with arithmetic-average-bound-blend crossover and wavelet mutation operator is applied to solve short-term variable-head hydrothermal scheduling problem. Initial feasible solution has been obtained by implementing the random heuristic search. The search is performed within the operating generation limits. Equality constraints that satisfy the demand during each time interval are considered by introducing a slack thermal generating unit for each time interval. Whereas the equality constraint which satisfies the consumption of available water to its full extent for the whole scheduling period is considered by introducing slack hydro generating unit for a particular time interval. Operating limit violation by slack hydro and slack thermal generating unit is taken care using exterior penalty method. The effectiveness of the proposed method is demonstrated on two sample systems.     

非强占型优先权的M/M/N可修排队系统

研究一类带有非强占型优先权、服务台忙时与闲时故障率不同的M/M/N可修排队系统,在画出系统状态转移图的基础上,得到系统瞬态概率密度满足的微分方程组。利用拟生灭过程的方法求出系统稳态条件,并在此基础上得到系统的稳态平衡方程组。通过对稳态方程组的分析得到系统中关键的N(N+1)/2个稳态概率值的求解思路,使用Mathematica软件编程实现了稳态概率值的求取过程,并举出一个具体实例。在得到稳态概率值的基础上给出了有效服务台数的稳态分布、稳态队长的母函数这两个系统指标。