遗传算法时间复杂性的研究

遗传算法的时间复杂是目前研究的焦点之一。本文以模式生存的概念为基础，将模式风险函数引入遗传算法的分析中，建立了一种随机可靠性模型，分析了遗传算法的时间复杂性。     

The M/PH/1 queue with working vacations and vacation interruption

We study an M/PH/1 queue with phase type working vacation and vacation interruption where the vacation time follows a phase type distribution. The server serves the customers at a lower rate in a vacation period. The server comes back to the regular busy period at a service completion without completing the vacation. Such policy is called vacation interruption. In terms of quasi birth and death process and matrix-geometric solution method, we obtain the stationary queue length distribution. Moreover we obtain the conditional stochastic decomposition structures of queue length and waiting time when the service time distribution in the regular busy period is exponential.     

带有滞留时间的流水作业计划排序方法研究

本文对带有滞留时间的流水作业车间以零件加工全长最小为目标的排序问题进行了分析和研究。分析证明了对于两台机床带有滞留时间的问题存在有效的多项式算法。本文还给出了三台以上机床带有滞留时间排序问题的启发式算法。     

STUDY ON AN SIS EPIDEMIC MODEL WITH TIME VARIANT DELAY

In this paper, we study an SIS epidemic model with a time variant delay. By means of Liapunov functional, some sufficient conditions of global stability to endemic equilibrium and disease free equilibrium have been obtained. The influence of time delay on the stability of equilibria is displayed.     

EFFECTS OF TOXICANTS ON CHEMTAT MODELWITH TIME VARIABLE NUTRIENT INPUT ANDWASHOUT

1.IntroductionItiswellknownthatchemostatmodelshavebeenwidelyinvestigatedinmanyliterature.[1MS].Itisprobablythebestsimulationinlaboratoryforthegrowthofplanktoniccommunitiesofunicellularalgaeandoceans.Inthereality,thelakesandoceansareoftenpolluted,soitisreasonableandimportanttoinvestigatechemostatmodelswithnutrientandtoxicantsinputtogether,andsomepapershavebeenpublishedrecentlytostudytheeffectoftoxicantsonthepopulationsinchemostatmodels[9--11].Butinthosechemostat-toxicantmodels,thewashoutratewa…     

货到人拣选系统多阶段可穿行多AGV路径规划

针对货到人拣选系统大规模多AGV（automated guided vehicle）路径规划中由于转弯和避障导致行驶时间增长的问题,考虑空载AGV可穿行货架,建立以任务完成时间最短为目标的路径规划模型,并通过改进A*算法对该问题进行求解。对AGV运行阶段进行划分,在A*算法中引入转弯惩罚值减少转弯次数,利用避障等待时间设置避障优先级。仿真实例结果表明考虑转弯和避障的可穿行货架路径规划方法能够降低任务完成时间和行走路径长度,在提高拣选系统作业效率方面具有参考价值。     

A GENERAL APPROACH BASED ON AUTOCORRELATION TO DETERMINE INPUT VARIABLES OF NEURAL NETWORKS FOR TIME SERIES FORECASTING

Input selection is probably one of the most critical decision issues in neural network designing, because it has a great impact on forecasting performance. Among the many applications of artificial neural networks to finance, time series forecasting is perhaps one of the most challenging issues. Considering the features of neural networks, we propose a general approach called Autocorrelation Criterion (AC) to determine the inputs variables for a neural network. The purpose is to seek optimal lag periods, which are more predictive and less correlated. AC is a data-driven approach in that there is no prior assumption about the models for time series under study. So it has extensive applications and avoids a lengthy experimentation and tinkering in input selection. We apply the approach to the determination of input variables for foreign exchange rate forecasting and conduct comparisons between AC and information-based in-sample model selection criterion. The experiment results show that AC outperforms inf     

THE DISTRIBUTION OF LIMIT POINTS OFINCREMENTS OF LOCAL TIME OF THE WIENER PROCESS

ThisresearchissupportedbythePostdoctoralGrantofChina.1.IntroductionLetW(t)for05t相似文献   

树约束线性加工时间的单机排序问题

讨论工件具有线性加工时间,工件间优先约束为树约束的单机排序问题。当目标函数为极小化加权完工时间和时,问题比相应的经典排序问题复杂,在工件间优先约束为出、入树2种情况下,分别给出了该问题最优排序的多项式算法。     

基于子波变换和AR模型的轴心轨迹识别

应用子波及子波向量，结合自回归时间序列ＡＲ模型，给出了大型旋转机械轴心轨迹的识别方法．该方法不仅能够反映轨迹的总体特征，而且还一定程度地描述了ｘ轴信号与ｙ轴信号的相关性．实验表明本方法具有较高的识别率．     

基于时间片段的多IT项目人力资源调度问题求解

针对多个IT项目的人力资源调度问题, 根据其在时间和人员方面的特殊要求, 可以将项目的演进时间划分 为相等的时间片段, 然后根据特定时间片段内的活动与可选人员之间的关系, 建立相应的人员调度方案搜索树. 将所有时间片段内的搜索树按顺序连接后, 可以得到总的方案树, 并列出所有的方案, 然后根据不同方案下得到的平均提前完工率和提前完工率方差, 找到最优解. 又为该搜索算法添加了启发规则, 使搜索空间急剧收缩, 极大提高了搜索效率. 基于该算法的特殊性, 可以将其用于求解许多具有与上述问题类似条件的资源调度问题. 本研究通过实例发现, 根据运算中的特殊规律, 该算法还具有进一步提取启发规则的潜力.     

SOME STABILITY THEOREMS FOR DIFFERENCE EQUATIONS WITH TIME DELAY

1.IntroductionDifferellceequationswithtimedelayhavebeenanimportantclassofmathematicallllodels.Fol'instance,inbiology,systemsofdifferenceequationshavebeedmuchusedtomodeltheinteractiollsofspecieswithlion-overlappinggeneration,butthemodelwillberelatedtodifferenceequationswithtimedelaywhenollemustconsidertheinfluenceoftimedelayeffectforspecies11limber.Thereisextensiveresearchondifferentialequationswithtimedelaybutthereisoillylittleworkdoneondifferenceequationswithtimedelay.Ouraimistoestablishstabi…     

链约束线性加工时间单机排序问题

讨论工件具有线性加工时间,工件间具有链约束的单机排序问题。目标函数为极小化加权完工时间和。在这类问题中,工件的加工时间是其开工时间的线性函数。对链不允许中断和链允许中断两种情况分别给出了最优算法。     

舰载机模块化弹药调度方案优化设计

舰载机模块化弹药存储和调度是未来发展的主要趋势之一。模块化弹药调度与整弹调度相比，调度对象的数量成倍增加并且多了一个弹药装配环节，使调度工作的难度呈指数级增长。针对模块化弹药调度问题，建立以任务完成时间最小化和各舱室与升降机平均工作时间最小化为优化目标，以各模块调度次序、机器选择和调度起始时间为约束条件的舰载机模块化弹药调度模型，设计递推法计算任务完成时间，并使用改进的遗传算法对模型进行求解，结合模块化弹药特点优化多层编码方式，使染色体更加完整地表达弹药在各个阶段的信息。通过仿真验证，所提的舰载机模块化弹药调度方法生成的调度方案具有可行性。     

SOME NEW RESULTS ON THE CONFIDENCELIMITS FOR RELIABILITY PARAMETERS IN THECASE OF NO FAILURES

1.IntroductionDenotethelifelengthofanyitemofsomekindofproductbyX.ThedistributionfunctionofXisF(t)(F(0)=0).Asiswellknown,themostimportantreliabilitypametersare:(1)R(t)=1--F(t)(reliatiility);(2)tR=tR(F)=sup{t:R(t)2R}(reliablespan);(3)M=M(F)=/ootdF(t)(averagelife).]0Inreliabilityengineeringoneofthemostimportanttasksistoestimatethesereliabilityparameters,especiallytogivegoodlowerconfidencelimitsforthem.Whenitemsofsuchaproductareputintoareliabilitytestitoftenhappensthatnofailureismet.Example…     

加工时间依赖开工时间的FlOW ShoP调度问题

讨论了加工时间依赖开工时间的Flow shop 调度问题。在这类问题中,工件的加工时间是开工时间的简单线性函数,机器间满足某种优势关系。对于这类问题,当目标函数是极小化最大完工时间时,尽管比相应的经典问题复杂,但仍存在多项式算法。如果目标函数是极小化加权完工时间和或极小化最大延误,则经典问题中的结论未必成立。     

A CLASS OF GENERALIZED MULTIPROCESSOR SCHEDULING PROBLEMS

1. IntroductionOne of the fundamental problems in the theory of scheduling is to sChedule n independent jobs non-preemptively on m 2 2 multiprocessors. It is well-known that PllCm.. andPI I Z:=, wiCi are strongly NP-hardll'2].In this paper, we consider a class of generalized multiprocessor scheduling problem. It canbe described as follows: There are m almost identical processors M = {MI, M2,'' 5 Mm}, andn independent jobs J = {JI, J2,'' 9 Jn}. The processing time of job Ji is pi. A…     

Stochastic Scheduling on an Unreliable Machine with General Uptimes and General Set－UpTimes

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短期生产计划中产品完成期的动态决策

生产计划和决策是一个企业成功运营的关键。在研究了产品完成期的基础上提出了动态甘特图 ,用于短期生产计划中产品完成期的动态决策。该动态甘特图具有形象、直观和易于决策等特点。仿真结果表明了它的有效性。     

A STAGE-STRUCTURED SI ECO-EPIDEMIOLOGICAL MODEL WITH TIME DELAY AND IMPULSIVE CONTROLLING*

This paper formulates a robust stage-structured SI eco-epidemiological model with periodic constant pulse releasing of infectious pests with pathogens. The authors show that the conditions for global attractivity of the ＇pest-eradication＇ periodic solution and permanence of the system depend on time delay, hence, the authors call it ＂profitless＂. Further, the authors present a pest management strategy in which the pest population is kept under the economic threshold level （ETL） when the pest population is uniformly persistent. By numerical analysis, the authors also show that constant maturation time delay for the susceptible pests and pulse releasing of the infectious pests can bring obvious effects on the dynamics of system.