A solid transportation problem with mixed constraint in different environment

In this paper, we have introduced a Solid Transportation Problem where the constrains are mixed type. The model is developed under different environment like, crisp, fuzzy and intuitionistic fuzzy etc. Using the interval approximation method we defuzzify the fuzzy amount and for intuitionistic fuzzy set we use the ($\alpha,\beta$)-cut sets to get the corresponding crisp amount. To find the optimal transportation units a time and space based with order of convergence $O (MN^2)$ meta-heuristic Genetic Algorithm have been proposed. Also the equivalent crisp model so obtained are solved by using LINGO 13.0. The results obtained using GA treats as the best solution by comparing with LINGO results for this present study. The proposed models and techniques are finally illustrated by providing numerical examples. Degree of efficiency have been find out for both the algorithm.     

A Lagrangian relaxation-based heuristic for the vehicle routing with full container load

We address a problem of vehicle routing that arises in picking up and delivering full container load from/to an intermodal terminal. The substantial cost and time savings are expected by efficient linkage between pickup and delivery tasks, if the time of tasks and the suitability of containers for cargo allow. As this problem is NP-hard, we develop a subgradient heuristic based on a Lagrangian relaxation which enables us to identify a near optimal solution. The heuristic consists of two sub-problems: the classical assignment problem and the generalized assignment problem. As generalized assignment problem is also NP-hard, we employ an efficient solution procedure for a bin packing based problem, which replaces the generalized assignment problem. The heuristic procedure is tested on a wide variety of problem examples. The test results demonstrate that the procedure developed here can efficiently solve large instances of the problem.     

Capacitated transportation problem with bounds on RIM conditions

Motivated by dead-mileage problem assessed in terms of running empty buses from various depots to starting points, we consider a class of the capacitated transportation problems with bounds on total availabilities at sources and total destination requirements. It is often difficult to solve such problems and the present paper establishes their equivalence with a balanced capacitated transportation problem which can be easily solved by existing methods. Sometimes, total flow in transportation problem is also specified by some external decision maker because of budget/political consideration and optimal solution of such problem is of practical interest to the decision maker and has motivated us to discuss such problem. Various situations arising in unbalanced capacitated transportation problems have been discussed in the present paper as a particular case of original problem. In addition, we have discussed paradoxical situation in a balanced capacitated transportation problem and have obtained the paradoxical solution by solving one of the unbalanced problems. Numerical illustrations are included in support of theory.     

地下矿山运输系统建模与仿真

系统仿真是系统工程领域的研究热点之一.针对大型地下矿山的运输这一庞大而复杂的系统,以云南锡业集团松树脚矿1360水平运输系统为研究对象,应用离散事件仿真原理,建立了运输系统模型.通过对某些运输参数的调整,确定了其最优的车辆分配,分析了运输系统效率,对该运输系统的运输能力做出了科学的评估.     

基于Stackelberg博弈的时变双层交通分配模型

提出一个时变双层交通分配模型,其中上层网络管理者设立了一个路段的最大排队长度,其目标是使由网络流和排队长度定义的总出行时间最小.目标函数在离散时段内以路段流量和排队长度作为决策变量,同时考虑不同类型的信号交叉口延误的影响.下层网络用户的反应依赖于上层管理者的决策,其选择是使自身感知阻抗最小的路径,服从一个基于成对组合Logit的路径选择模型,构成一个成对组合Logit的均衡分配问题.结合了交通分配和流传播方法,将其表示为一个均衡约束下的双层数学规划问题,形成了一个Stackelberg非合作博弈.使用遗传算法求解该双层规划问题,并采用实证分析来表现模型的特征和算法的计算表现.结果表明路径重叠、路段流量、路段排队长度等因素对网络均衡流分布均有显著影响.     

基于NSGA-II的应急生产任务多目标优化模型及算法研究

重大突发事件发生后,若灾区的应急物资需求不能通过调用储备得到满足,则应急生产将成为灾区应急物资供应的重要保障手段。本文研究重大突发事件发生后应急物资生产任务的优化问题,重点关注原材料生产能力变化对完成应急生产任务的影响,以应急生产任务完成时间最短、完成成本最低为决策目标,研究了包含多个供应商、多个制造商以及单个受灾点的应急物资生产任务多目标规划模型。运用在求解多目标规划问题时具有众多优势的非支配排序多目标遗传算法(NSGA-II)对模型进行求解。通过算例分析,NSGA-II可以得到较好的Pareto前沿,并且可以根据不同情况给出最优的应急物资生产和原材料保障方案。本文的研究还表明,要想更快完成应急生产任务,需要做好原材料、资金、电力、交通等各种要素的配套保障工作。     

Direct observation of the carrier transport process in InGaN quantum wells with a pn-junction

A new mechanism of light-to-electricity conversion that uses InGaN/GaN QWs with a p-n junction is reported.According to the well established light-to-electricity conversion theory,quantum wells(QWs) cannot be used in solar cells and photodetectors because the photogenerated carriers in QWs usually relax to ground energy levels,owing to quantum confinement,and cannot form a photocurrent.We observe directly that more than 95% of the photoexcited carriers escape from InGaN/GaN QWs to generate a photocurrent,indicating that the thermionic emission and tunneling processes proposed previously cannot explain carriers escaping from QWs.We show that photoexcited carriers can escape directly from the QWs when the device is under working conditions.Our finding challenges the current theory and demonstrates a new prospect for developing highly efficient solar cells and photodetectors.     

随机交通网络渐近连通可靠性分析

应用原有拓扑法获得城市交通网络的拓扑结构图,利用对偶拓扑法得到交通网络的对偶图,建立交通网络的随机网络模型。定义交通网络的渐近连通可靠性,得到路段连通可靠性、路网规模及整个路网连通可靠性之间的定量关系,结合随机图论、大数定律、渐近方法等证明所得结论;通过实例说明结论的应用价值。     

危险品物流中的多目标定位-路径问题

随着经济的增长,危险化学品需求呈日益增长的趋势,其安全储运问题已成为政府和企业关注的焦点。本文通过建立危险品物流中多配送中心、多目标定位—路径问题优化模型,并设计混合遗传算法对模型进行求解,最后通过算例验证该模型和算法的可行性和有效性。结果表明:与只考虑系统总成本的结果相比,考虑运输风险的结果能够以较小的风险和成本、较少的人力资源配备实现危险品的储运;所设计混合遗传算法具有良好的性能。     

基于高维突变模型的海上通道安全预警研究

为了在海上通道突发事件发生前给出可能的危险等级,减少海上通道突发事件造成的损失和提高海上通道预警与应急管理能力,本文针对海上通道安全突发事件的复杂性,提出一种历史案例分析与高维突变级数相结合的新方法。首先,通过对历史突发事件案例的统计分析,得出海上通道安全的主要风险源因素,并由此建立了海上通道安全预警指标体系。其次,将突变级数法在高维指标应用方面进行了推广,建立海上通道安全预警模型,并根据历史案例数据计算模型的预警阈值。最后,选取了实际案例对预警模型进行了检验,检验结果表明模型可以对海上通道突发事件进行有效预警。