Sensitivity analysis for stochastic user equilibrium with elastic demand assignment model

This paper puts forward a rigorous approach for a sensitivity analysis of stochastic user equilibrium with the elastic demand （SUEED） model. First, proof is given for the existence of derivatives of output variables with respect to the perturbation parameters for the SUEED model. Then by taking advantage of the gradient-based method for sensitivity analysis of a general nonlinear program, detailed formulae are developed for calculating the derivatives of designed variables with respect to perturbation parameters at the equilibrium state of the SUEED model. This method is not only applicable for a sensitivity analysis of the logit-type SUEED problem, but also for the probit-type SUEED problem. The application of the proposed method in a numerical example shows that the proposed method can be used to approximate the equilibrium link flow solutions for both logit-type SUEED and probit-type SUEED problems when small perturbations are introduced in the input parameters.

Sensitivity analysis method for increasing the passenger demands of parking and riding

Focused on finding out the relationship between passenger demands of P&R and its influencing factors, a nested-logit mode choice model was developed based on the characteristic of different modes and transfer rules. The utility functions were given respectively according to the characteristic of each alternative. Passenger demands of different modes between O-D pairs were obtained by making use of the binary logit model. Then an equilibrium model for different modes was proposed. Under this condition, the approximate relationship between passenger demands of different modes and their characteristic indexes was modeled by the sensitivity analysis method. Shift volume among different modes was achieved by utilizing this model when their characteristic indexes were changed. A case study indicates that the model and algorithm presented in this paper are effective.

Analysis of an Inventory System for Items with Price-Dependent Demand and Time Dependent Three-Parameter Weibull Deterioration Function

In this research work we propose a mathematical model of an inventory system with time dependent three-parameter Weibull deterioration and price-dependent demand rate. The model incorporates shortages and deteriorating items are considered in which inventory is depleted not only by demand but also by decay, such as, direct spoilage as in fruits, vegetables and food products, or deterioration as in obsolete electronic components. Furthermore, the rate of deterioration is taken to be time-proportional, and a power law form of the price dependence of demand is considered. This price-dependence of the demand function is nonlinear, and is such that when price of a commodity increases, demand decreases and when price of a commodity decreases, demand increases. The objective of the model is to minimize the total inventory costs. From the numerical example presented to illustrate the solution procedure of the model, we obtain meaningful results. We then proceed to perform sensitivity analysis of our model. The sensitivity analysis illustrates the extent to which the optimal solution of the model is affected by slight changes or errors in its input parameter values.

基于多方法综合比较的南水北调西线工程水源区生态需水研究

针对南水北调西线工程调水需求,以方法比选、目标修正、可行性验证为主线,提出了一套多方法综合确定水源区生态需水过程的思路,并制定了10个坝址断面枯水期和非枯水期的生态基流、敏感生态需水及年生态水量目标。结果表明:水源区坝址断面枯水期生态基流在多年平均流量中的占比约为20%,非枯水期占比约为40%;3—6月为鱼类集中产卵敏感期,需要每月发生一次脉冲流量过程,每次至少持续10 d,脉冲流量在多年平均流量中的占比为48%~73%;各坝址断面年均生态水量在多年平均径流量中的占比约为70%,其中丰水年、一般偏枯年、枯水年生态水量占比分别为68%~78%、66%~75%和61%~70%;研究结果符合长江流域现有管控要求,具备较好的现实可达性。

考虑旱灾风险的水库分级分期旱警水位内涵与确定方法

水库蓄水是重要的抗旱应急水源,设定水库旱警水位是提高水库抗旱减灾能力的重要措施。本文基于已有成果,拓展旱警水位的概念与内涵,提出了轻旱、中旱等干旱典型年Ⅰ级、Ⅱ级、Ⅲ级与Ⅳ级分级、分期旱警水位的控制原则;将水库调度模型与计算农业需水量与需水过程的AquaCrop-OSPy模型结合,以农业生产因旱损失风险最小为目标,模拟不同等级干旱典型年在不同初始水位下的水库运行过程与农业生产因旱损失风险,并绘制农业生产因旱损失风险曲线;以损失风险等级分界点所对应的水库水位为分级旱警水位;采用AquaCrop-OSPy模型模拟多种灌溉方案下各典型年的农业生产,计算各月供水率与农业减产率的偏相关系数,来表示各月的需水敏感度,以此作为时段水量对冲和旱警水位分期的依据。以东庄水库为例,选择其供水区域内的主要农作物夏玉米与冬小麦进行了实例分析。结果表明:旱警水位的分级与分期控制反映了临界调控理论与水量的时空对冲调控;农业生产因旱损失风险变化曲线呈现连续、多拐点、三阶段的变化特征,东庄水库轻旱年旱警水位为Ⅳ级预警,中旱和重旱年为Ⅳ级、Ⅲ级与Ⅱ级预警,特旱年为Ⅱ级、Ⅰ级预警,旱警水位从时间上分为7—12月、1—4月和5—6月三期。

机理-数据混合驱动的气象敏感负荷需求响应潜力评估

为准确评估电网中气象敏感负荷需求响应潜力,提出了一种基于机理-数据驱动方法融合的气象敏感负荷需求响应潜力评估方法。该方法根据数据驱动的双分支神经网络模型估算电网层级的气象敏感负荷功率,基于热力学等值模型建立气象敏感负荷的机理聚合模型,并以聚合功率与估算功率误差最小为目标,采用控制变量法和粒子群优化算法优化确定机理聚合模型的等效参数(温控负荷设备数量、温度设定值等),同时综合考虑用户舒适度与意愿度等因素评估气象敏感负荷需求响应潜力。实例验证结果表明,该方法估算的气象敏感负荷功率与温度具有显著相关性,获得的机理聚合模型等效参数及需求响应潜力与实际情况相符且合理。

基于不确定性分析的供水管网压力监测点优化布置

针对现有供水管网压力监测点布置中产生的异参同效问题,基于正态分布利用蒙特卡罗随机抽样法分析管网节点需水量的不确定性,引入节点压力波动系数,讨论节点需水量的随机性对供水管网全局的影响,结合节点水压灵敏度,解决供水管网压力监测点布置中存在的异参同效问题。以华东某城区供水管网为例,结合水压相关性与水压灵敏性构建模型,采用蝙蝠算法求解,获得测压点布置方案。以稳态水力模型的节点需水量初始值为基准进行20 000次随机抽样,应用抽样值进行模拟,计算节点压力波动系数与节点灵敏度,确定最优方案,解决异参同效问题,为供水管网压力监测点布置方案的选取提供了新思路。

AN OPTIMAL DYNAMIC ADVERTISING MODEL WITH INVERSE INVENTORY SENSITIVE DEMAND EFFECT FOR DETERIORATING ITEMS

This paper proposes a dynamic advertising model for deteriorating items, and the demand is influenced by goodwill and inventory level. The goodwill affected by advertising effort has a positive effect on demand while the inventory level has a negative effect on demand, which is named as inverse inventory sensitive demand effect. We assume that the deteriorating rate could be influenced by the inventory level and we determine the deteriorating rate formulation based on this assumption. The optimal advertising effort and inventory level are obtained by solving the optimization problem based on Pontryagin＇s maximum principle. Furthermore, numerical studies are provided and some managerial insights are presented.

Demand-Driven Memory Leak Detection Based on Flow-and Context-Sensitive Pointer Analysis

We present a demand-driven approach to memory leak detection algorithm based on flow- and context-sensitive pointer analysis. The detection algorithm firstly assumes the presence of a memory leak at some program point and then runs a backward analysis to see if this assumption can be disproved. Our algorithm computes the memory abstraction of programs based on points-to graph resulting from flow- and context-sensitive pointer analysis. We have implemented the algorithm in the SUIF2 compiler infrastructure and used the implementation to analyze a set of C benchmark programs. The experimental results show that the approach has better precision with satisfied scalability as expected.

军事干预需求、规范敏感性与大国海外安全市场化发展模式

冷战后,私营军事安保公司在大国普遍出现,但是这些国家安全市场化的发展模式有所不同。有些大国采取作战型模式,一些大国属于安保型模式,也有大国从作战型模式转为军事辅助型模式。作者以海外军事干预需求和规范敏感性为变量,搭建大国海外安全市场化发展模式的解释框架,着重讨论国家和公司的关系。当海外军事干预需求强、规范敏感性低时,大国出现作战型发展模式;当海外军事干预需求强、规范敏感性高时,大国采取军事辅助型模式;当海外军事干预需求弱、规范敏感性高时,大国出现安保型模式。世界主要大国海外安全市场化的发展经验证实了上述假设。英国和美国的案例比较分别验证了大国的作战型模式和军事辅助型模式的成因,而印度和日本的案例论证了安保型模式产生的逻辑。当前,中国加强海外利益保护的需求日益迫切,讨论大国海外安全市场化的发展,对中国借助市场化手段保障海外利益安全也有一定的启发。

A single-manufacturer multi-retailer sustainable reworking model for green and environmental sensitive demand under discrete ordering cost reduction

This paper develops an economic production quantity(EPQ)model for a singlemanufacturer multi-retailer(SMMR)production and reworking system with green and environmental sensitive customer demand.The minimum cost of the manufacturer has obtained under carbon emissions(CE)policies and discrete ordering cost reduction.The model is used to optimize the total number of shipments,greening investment level,environmental measure,and lot size for productions and rework.This research work determines that the manufacturer’s and retailer’s profits will be increased after considering the environmental and green dependent demand of customers.Further,the development of green and environmental demand is proposed to minimize the CE and maximize the demand for the customers.In the existing literature,no discrete investment is developed for reducing the cost of ordering for the retailer/buyer.However,in this paper,we have introduced it.We provide numerical examples to explain the models and determine the significance of model parameters.

价格、时间敏感需求下的价格与交付期竞争策略

针对价格、时间敏感需求,且市场间具有替代性的产品价格与交付期决策问题,构建相关决策模型并对模型的最优性进行分析。通过数值算例,探讨了交付期选择、企业特征(包括产能及直接成本特征)对决策的影响,以及当企业面临不同竞争市场时,如何选择价格与交付期竞争策略。研究结论可以为企业科学进行市场竞争提供有益的指导。

具有心电显示功能的临时心脏按需起搏器的开发研究

介绍了一种具有心电显示功能的临时心脏按需起搏器。由双路低噪声心电前置放大器、限幅器、高通和低通滤波器、5 0 Hz陷波器、TTL 电平发生器以及刺激脉冲形成电路等组成硬件电路。计算机和软件部分采用双微控制器通信技术 ,并由软件分别控制按需起搏和心电显示。本研究首创在临时心脏起搏器安置和运行的同时 ,由液晶屏显示实时体表或心内电生理信号。经临床使用 ,效果良好 ,具有明显的推广和应用价值。

投入产出弹性系数研究

为了研究产业结构变动和产业部门间的关联程度,需要计算投入产出弹性系数。根据矩阵理论,对投入产出弹性系数进行分析,提出了一种新的确定弹性系数的方法。该方法不仅考虑直接消耗系数变动所引起的各个部门产出的相对变动,而且还考虑了最终需求结构对部门产出的影响。最后计算了中国1992年和1995年18部门的弹性系数,同时将投入产出表中部门间相互关系最为敏感的连接通过图表示出来,得到了一些有意义的结果,数值结果表明本方法是有效的有效性。

一种可操作的需求侧管理峰谷分时电价定价方法

运用经济学原理研究了峰谷分时电价的市场效应,建立了基于电力需求价格弹性矩阵的峰谷分时电价数学模型,提出了电网总售电收入(用户电费支出)对电网负荷变化的反应灵敏度概念。通过对该模型的目标函数进行优化,得到了一种可操作的峰谷分时电价定价方法。算例仿真分析表明所提出的分时电价定价方法是切实可行的,它有利于减小电网的高峰负荷,改善负荷曲线,提高系统运行的可靠性和经济性,实现资源的优化配置和电力工业的可持续发展。

需求具有价格敏感性的供应链收益共享契约设计研究

本文研究了供应链收益共享契约的协调问题。在综合考虑最终销售价格为内生变量和剩余产品残值与生产成本相关的情况下,建立了供应链收益共享契约协调模型,并借助报童模型对零售商和供应商的决策行为进行分析,给出零售商最优决策行为和契约参数(?)取值范围的计算公式。最后进行了数值实例分析,验证了供应链收益共享契约的有效性。

基于NILM技术的家庭用户精确负荷建模方法

结合非侵入负荷监测NILM系统的负荷辨识流程,本文提出了一种基于NILM技术的家庭用户精确负荷建模方法。该方法应用NILM技术提取家庭主要设备负荷特性。然后通过模糊C聚类法实现家庭负荷模型归类,获得设备针对不同电价的转移灵敏度和自灵敏度用电特性,并在此基础上形成家庭负荷特性。通过电网公司分时电价环境下实测的家庭典型用电负荷数据验证可知,空调、洗衣机、热水器、电动汽车具有较大的弹性,其中洗衣机的自弹性和交叉弹性最大,在高电价时段可削减100%。该方法所获得的家庭负荷辨识的结果,可支持居民电价/激励等需求侧管理政策的制定,也可支持用户家庭用电设备状态监测服务等。

计及时滞指标综合灵敏度的用户电价响应模式划分方法

基于电量电价弹性矩阵,提出了电价响应时滞性的概念与数学模型,研究了时滞响应的稳定状态,量化了时滞性指标。结合需求响应弹性系数,对335个用户进行需求响应分析,采用模糊C均值聚类方法,将具有共同电价响应特征的用户分类,并用不同用户时间断面负荷曲线验证了该分类结果的有效性。结合需求响应弹性系数,利用综合灵敏度矩阵对多个用户进行分析,将具有共同响应特征的用户分类,扩大了响应矩阵的维度,扩展了用户的响应信息。算例结果表明,该时滞性指标能快速找出对电价调整有响应的用户,并对用户响应时滞性能做出评价。该方法对减小响应不确定性,修正购售电计划、调度方式、交易计划有积极意义。

基于多维性能极限状态的概率地震需求分析

基于概率地震需求分析(PSDA),分别采用增量动力和非线性时程分析,得到某框架结构的最大层间漂移比和最大加速度响应,通过定义多维性能极限状态的性能水准,计算该结构的多维地震易损性,联合地震动危险性曲线,建立了年平均超越概率的三重积分公式,采用梯形法求得50年内地震需求(漂移)危险性曲线。在此基础上,进行了同时考虑性能极限状态的随机性和相关性对结构需求危险性的敏感性分析。在性能极限状态不确定性中选择适当的变异系数(cidrcpfa)及相互作用因子NID R,能够使年平均超越概率增加;相比单一极限状态,考虑二维极限状态的年平均超越概率也将提高。研究结果表明,所提方法可描述对多维响应参数敏感的结构破坏行为,可获得设计基准期内更加符合实际的结构需求危险性曲线,为震后损失估计提供可靠的理论依据。

基于服务能力的产品服务化供应链协调对策研究

针对由功能服务商、服务集成商、客户构成的产品服务化供应链系统,以服务敏感性随机需求为视角,结合服务能力闲置或不足所引起的成本费用,分别从功能服务商和服务集成商角度,建立了产品服务化供应链的收益模型和协调机制模型。通过实例深入分析服务敏感性需求变化对于产品服务化供应链总收益的影响,并给出了产品服务化供应链协调管理的对策。