基于多数量需求拍卖机制的动态存贮/分配模型

该文分析了折扣准则下基于多数量需求拍卖机制的多阶段存贮问题,运用动态规划方法,在有限阶段对该问题研究了每个时期应该出售的最优产品数量、最优分配方案和最优订购策略,提出了运用修正的多需求二级价格拍卖模型来实现最优分配,并对无限阶段下的动态存贮/分配问题进行了讨论.     

基于多层博弈的智能电网住宅电力实时需求响应机制

通过建立多层博弈模型刻画智能电网系统中电力公司、家庭电力管理中心和家庭内各个电器设备间的电力实时需求响应过程。在此模型中,每个时段电力公司将电价通知各个家庭,每个家庭的电力管理中心接收到实时电价信息后为家庭内各个电器设备分配虚拟电价,各个设备则确定各自最优用电量并将其反馈给家庭电力管理中心,由其确定该家庭总用电量并发送至电力公司,电力公司再计算得到最优电价。证明了所建多层博弈模型的均衡存在唯一性,并得到均衡解。仿真结果验证了模型的有效性,并给出其实际应用价值。     

面向不同占用率水平的泊位共享动态定价策略

为了满足停车场多方利益需求,实现区域内泊位占用率均衡的目标,提出了面向不同泊位占用率水平的动态定价策略.基于车主停车行为特征测算泊位综合效用及车主选择泊位概率,在预测停车场泊位需求的基础上构建定价模型,确定了区域内不同占用率水平下的目标函数,最终引入遗传算法进行优化求解.结果表明:利用构建的动态定价模型能够有效调整区域内泊位占用率水平,实现不同水平下的多方利益最大化,提高社会效益.     

收入管理中多数量需求的动态分批拍卖机制研究

分析了可运用于收入管理的定价及分配存量的动态分批拍卖机制,传统拍卖机制假设竞标者是单一需求,与实际情况不相符合.本文研究的模型中一个卖方在有限时间限制T内采用分批拍卖的方式销售商品出售C件产品,每个时期的竞标者有着多数量的产品需求,并对所需求产品有统一的,独立的私有价值.为使得整个拍卖收益最大化,研究了最优的分配方案和每个时期应该出售的最优产品数量kt*(x),并且运用改进的多需求第二价格拍卖模型实现最优分配机制.     

民航值机人员动态排班问题研究

由于机场地服人员的工作时间具有特殊性,人员需求量通常是由航班数量决定的,一天之中的航班量有高峰和低谷时段,因此不同时段的人员需求也不同.目前大多数机场的值机人员排班实行均衡小组排班制度,每个班次人数均衡,导致人员利用效率差.因此本文首先利用排队论对员工需求进行预测,基于均衡小组排班制度的弊端,提出了组内动态排班模型,并利用此模型进行实例验证,最后提出动态调整的措施.对比均衡小组排班和模型排班结果发现,组内动态排班不仅能够方便进行人员管理,而且提高了员工的工时有效率,减少了人力资源的浪费.     

非对称弹性需求网络容量限制交通分配有效算法

在非对称交通网络中,针对路段容量限制下弹性需求用户均衡分配模型计算困难,提出了一种路段容量限制弹性需求用户均衡交通分配问题的有效算法.该算法在迭代时,排队延误因子、误差因子与交通需求通过自适应调节来逼近真实路段车辆行驶时间和出行者交通需求,促使各路段交通流量逐步满足限制条件,最终达到弹性需求广义用户均衡.方法克服了容量限制弹性需求用户均衡分配计算量大及随机分配法要求枚举所有路径的困难.随后证明了算法的收敛性,并对一个小型路网进行了数值试验.     

随机需求下多供应商和多零售商的生产-库存-运输联合优化模型

考虑随机需求下多供应商和多零售商的生产-库存-运输联合优化问题.在联合优化时,首先利用最近邻算法将各零售商分成不同区域,分区后问题转化为随机需求下单供应商对多零售商的生产-库存-运输联合优化问题.在每个分区内,由供应商统一决策其分区内各零售商的送货量和送货时间.利用粒子群算法和模拟退火算法相结合的两阶段算法求出最优送货量、最优运输路径和最大期望总利润.然后采用收入共享契约将增加的利润合理分配给各供应商和各零售商,使各方利润都得到增加,从而促使各方愿意合作.通过数值算例验证了联合优化模型优于独立决策模型.     

基于退化效应的两台机器流水作业可拒绝排序

考虑了工件具有退化效应的两台机器流水作业可拒绝排序问题,其中工件的加工时间是其开工时间的简单线性增加函数.每个工件或者被接收,依次在两台流水作业机器上被加工,或者被拒绝但需要支付一个确定的费用.考虑的目标是被接收工件的最大完工时间加上被拒绝工件的总拒绝费用之和.证明了问题是NP-难的,并提出了一个动态规划算法.最后对一种特殊情况设计了多项式时间最优算法.     

顾客延时离开的共享车位预订控制策略研究

基于车位共享用户未按约定时间离开而导致车位使用时间冲突的问题,构建了随机动态规划模型。通过模型,研究了平台的预订控制策略,并针对平台能否拒绝延时需求的情形,设计两种算法对模型进行求解,最后通过数值仿真验证了算法的有效性。研究结果表明:(1)随着预订周期的增加,平台的边际收益会先增加后减少,因此存在最优预订周期;(2)若平台可以决策延时需求是否被接受,则随着延时概率的增加,机会成本将减少,而平台服务率和车位利用率将增加;(3)若平台只能被动接受延时需求,则随着延时概率的增加,平台服务率将减少,而机会成本和车位利用率将增加。     

多周期多产品采购量分配优化模型

为了解决随机需求与价格折扣并存条件下的多周期多产品采购量分配问题,建立了相应的多目标混合整数随机规划模型.该模型的特点是:①模型的约束条件中兼具确定性和随机性;②通过累计需求和累计采购量表示多周期的库存持有成本;③通过约束条件方程式准确地表现随机需求和价格折扣两大假设条件.针对该模型的特殊结构,提出了一种适用的求解策略:首先,通过把机会约束转化为确定性等价类,从而将多目标混合整数随机规划模型转化为确定型多目标混合整数规划模型;然后,采用目标规划法求得问题的满意解.此外,通过应用算例说明了模型的有效性和可行性.     

双模式网络停车限制交通需求管理模型与方法研究

在轨道网和公路网并存的双模式交通网络, 合理设计出行终点的停车容量可优化汽车出行需求, 改善路网交通环境。本文通过分析私家车与城市轨道两种交通模式的出行需求, 并考虑私家车模式的终点停车收费服务, 建立了一种带路段环境容量和终点停车需求容量共同约束的交通需求管理模型。模型中路网使用者的出行模式采用二元Logit模型来计算, 而私家车的路线选择行为服从Logit随机用户均衡, 因此该模型是一个带不动点约束的数学规划问题。针对模型求解困难, 文中采用灵敏度分析来获取各路段流量和需求量关于终点容量波动的梯度信息, 进而设计了一种新的灵敏度分析求解算法.最后通过数值仿真实验, 验证了算法的有效性, 同时分析了不同停车收费参数对模型各指标变化趋势的影响。     

Parking Capacity and Pricing in Park'n Ride Trips: A Continuous Equilibrium Network Design Problem

In this paper we consider the problem of designing parking facilities for park'n ride trips. We present a new continuous equilibrium network design problem to decide the capacity and fare of these parking lots at a tactical level. We assume that the parking facilities have already been located and other topological decisions have already been taken.The modeling approach proposed is mathematical programming with equilibrium constraints. In the outer optimization problem, a central Authority evaluates the performance of the transport network for each network design decision. In the inner problem a multimodal traffic assignment with combined modes, formulated as a variational inequality problem, generates the share demand for modes of transportation, and for parking facilities as a function of the design variables of the parking lots. The objective is to make optimal parking investment and pricing decisions in order to minimize the total travel cost in a subnetwork of the multimodal transportation system.We present a new development in model formulation based on the use of generalized parking link cost as a design variable.The bilevel model is solved by a simulated annealing algorithm applied to the continuous and non-negative design decision variables. Numerical tests are reported in order to illustrate the use of the model, and the ability of the approach to solve applications of moderate size.     

基于遗传算法的交易中心停车场优化设计

根据某交易中心大型停车场的实际情况 ,并利用大型客车和轿车的长度、宽度、最小转弯半径等数据 ,建立了停车场优化停车设计模型 ,采用遗传算法进行求解 ,得到了停车场的最优停放布局和车位排列角度的优化结果 .本文优化设计的思想、方法和结果对其他大型停车场优化设计也有一定的参考价值 .     

Dynamic cost allocation for economic lot sizing games

We consider a cooperative game defined by an economic lot sizing problem with concave ordering costs over a finite time horizon, in which each player faces demand for a single product in each period and coalitions can pool orders. We show how to compute a dynamic cost allocation in the strong sequential core of this game, i.e. an allocation over time that exactly distributes costs and is stable against coalitional defections at every period of the time horizon.     

A continuous day-to-day traffic assignment model and the existence of a continuous dynamic user equilibrium

Suppose that a road network model is given, together with some given demand for travel by (say) car and that the demand for travel varies with time of day but not from day to day. Suppose that this demand is given in the form of specified total outflow rates from each origin headed towards each destination, for each origin-destination pair and for each time of day, and that some initial time-dependent routeinflow rates, meeting the given demand, are given. Finally, suppose that within-day time is represented by a continuous variable. This paper specifies a natural smooth day-to-day route-swapping procedure wherein drivers swap toward less expensive routes as day succeeds day, and shows that under reasonable conditions there is an equilibrium state of this dynamical system. If such a collection of route-inflows has arisen today, say, then there is no incentive for any route-inflow to change tomorrow, in the sense that at each moment of today each of today's route-inflows isalready on a route which today yielded the smallest travel cost. Such a set of no-incentive-to-change route-inflows is called adynamic equilibrium, or adynamic user-equilibrium, and may be regarded as a solution of the dynamic equilibrium traffic assignment problem. Thus, the paper introduces a smooth day-to-day dynamic assignment model and, using this model, shows that there is a dynamic user-equilibrium in a continuous time setting. The paper briefly considers the day-to-day stability of the route-swapping process, also in a continuous setting. Finally, the paper gives a simple dynamical example illustrating the stability of the route-swapping process in a simple two-route network when there is deterministic queueing at bottlenecks.     

停车设施选址的双层规划模型

为了解决城市停车难问题,针对目前日益紧张的土地资源和快速增长的交通流量,考虑停车设施对路网上交通流的影响,提出一种在土地利用规划基础上的,对路网影响最小,停车场使用者步行时间最省的停车设施选址的双层规划模型,借助现有的交通规划软件(Emme)进行求解,并应用于上海市江湾-五角场副中心地区停车设施规划研究中.     

Planning vehicle transhipment in a seaport automobile terminal using a multi-agent system

A multi-agent system (MAS) for supporting the planning of transhipments of imported finished vehicles via a seaport is presented. The focus is on storage allocation, i.e. the allocation of parking areas for the temporary storage of vehicles, and on deployment scheduling, i.e. the allocation of drivers to the vehicles that have to be moved in the terminal area. These planning tasks, which in practice are usually carried out by different operators, are assigned to two different agent types. A further agent, the coordinator agent, is responsible for combining the local sub-plans into an overall plan in such a way that the demand for drivers in the planning period is minimised and balanced. The MAS is tested using randomly generated problem instances with different distributions of the manufacturer shares in the vehicle streams. The tests verify a certain robustness of the MAS with regard to changes in the problem data, in particular to the number of permanently employed drivers and the cost surcharge for hired drivers. In addition, the results highlight that the minimum overall (relative) costs of the drivers depends on the number of permanently employed drivers and on the level of the cost surcharge for hired drivers.     

A Model for Evaluation of Transport Policies in Multimodal Networks with Road and Parking Capacity Constraints

This paper presents a model for evaluation of transport policies in multimodal networks with road and parking capacity constraints. The proposed model simultaneously considers choices of travelers on route, parking location and mode between auto and transit. In the proposed model, it is assumed that auto drivers make a simultaneous route and parking location choice in a user equilibrium manner, and the modal split between auto and transit follows a multinomial logit formulation. A mathematical programming model with capacity constraints on road link and parking facilities is proposed that generates optimality conditions equivalent to the requirements for multimodal network equilibrium. An augmented Lagrangian dual algorithm embedded by partial linearization approach is developed to solve the proposed model. Numerical results on two example networks are presented to illustrate the proposed methodology. The results show that the service level of transit, parking charges, road link and parking capacities, and addition of a new parking location may bring significant impacts on travelers’ behavior and network performance. In addition, transport policies may result in paradoxical phenomenon.     

An approach for integrated scheduling and lot-sizing

In this paper a non time discrete approach is developed for an integrated planning procedure, applied to a multi-item capacitated production system with dynamic demand. The objective is to minimize the total costs, which consist of holding and setup costs for one period. The model does not allow backlog. Furthermore, a production rate of zero or full capacity is the only possibility. The result is a schedule, lot-sizes and the sequences for all lots. The approach is based on a specific property of the setup cost function, which allows for replacement of the integer formulation for the number of setup activities in the model. In a situation where the requirements for the multi-item continuous rate economic order quantity, the so-called economic production lot (EPL) formula, are fulfilled, both the EPL as well as the presented model results are identical for the instances dealt with. Moreover, with the new model problems with an arbitrary demand can be solved.