五品联动模式下品位决策问题建模与优化

矿冶工程中,地质品位、采出品位、入选品位、精矿品位、入炉品位是互为条件、相互联系的,对其进行实时动态优化是“五品联动”矿冶工程管理模式的基础。本文通过考察开采、配矿、选矿和冶炼过程中的品位与产量关系,推导出各阶段的品位与成本的关系模型,并在该模型的基础上进行边际分析,得出各阶段的品位-成本边际模型。建立了相应的品位-链接成本关系模型,并此基础上提出了品位-成本边际指数。最后,提出了五品联动的品位优化方法并给出具体步骤。文中还应用鞍钢矿业的实际数据进行了公式计算,结果和实际生产的情况吻合。     

能源消费结构统计特征研究

采用移动平均、HP滤波、VAR模型等方法对中国能源消费结构的循环及趋势特征进行研究,结果表明：化石能源消费对新能源消费影响通过GDP波动而发生作用,强化能源利用效率,维持GDP的稳定增长有助于中国能源消费结构优化,克服循环因素波动的影响。从强化提升新能源消费水平的角度看,煤炭／石油消费量的上升会拉动新能源／天然气消费量的增加,而新能源消费量上升会抑制煤炭／石油消费量的上升。因此,在中国能源消费结构上,新能源与煤炭／石油之间存在一种制衡机制,这也印证了中国产业政策取向和能源消费结构优化政策的合理性。基于此,针对性的提出了相关能源消费结构优化对策。     

INVENTORY PROCESSES: QUASI-REGENERATIVE PROPERTY,PERFORMANCE EVALUATION,AND SENSITIVITY ESTIMATION VIA SIMULATION

We consider a single-commodity, discrete-time, multiperiod (s, S)-policy inventory model with backlog. The cost function may contain holding, shortage, and fixed ordering costs. Holding and shortage costs may be nonlinear. We show that the resulting inventory process is quasi-regenerative, i.e., admits a cycle decomposition and indicates how to estimate the performance by Monte Carlo simulation. By using a conditioning method, the push-out technique, and the change-of-measure method, estimates of the whole response surface (i.e., the steady-state performance in dependence of the parameters s and S) and its derivatives can be found. Estimates for the optimal (s, S) policy can be calculated then by numerical optimization.     

An R package and a study of methods for computing empirical likelihood

Empirical likelihood (EL) is an important nonparametric statistical methodology. We develop a package in R called el.convex to implement EL for inference about a multivariate mean. This package contains five functions which use different optimization algorithms but meanwhile seek the same goal. These functions are based on the theory of convex optimization; they are Newton, Davidon–Fletcher–Powell, Broyden–Fletcher–Goldfarb–Shanno, conjugate gradient method, and damped Newton, respectively. We also compare them with the function el.test in the existing R package emplik, and discuss their relative advantages and disadvantages.     

Parameter Estimation Algorithms for the Hyper-Gamma Distribution Class

Microcomputer-based algorithms for the estimation of the parameters shift, scale, initial and terminal shape of the hyper–Gamma distribution class are presented. They are based on the moment equations and on the logarithmic likelihood function (LLF) associated with the hyper-Gamma density. The maximum–likelihood approach is implemented by means of the derivative equations resulting from the LLF and, independently, by means of direct optimization of the LLF. Program options include estimation of (i) four parameters, (ii) three parameters (shift known), and (iii) two parameters (shift known, initial shape zero). A program diskette with user's guide will be made available upon request.     

Optimal two-stage designs for phase ii clinical trials with differentiation of complete and partial responses

In the usual design and analysis of a phase II trial, there is no differentiation between complete response and partial response. Since complete response is considered more desirable this paper proposes a weighted score method which extends Simon's (1989) two-stage design to the situation where the complete and partial responses are differentiated. The weight assigned to the complete response is suggested by examining the likelihood ratio (LR) statistic for testing a simple hypothesis of a trinomial distribution. Both optimal and minimax designs are tabulated for a wide range of design parameters. The weighted score approach is shown to give more efficient designs, especially when the response probability is moderate to large.     

直接配送下随机需求库存-路径问题最优平稳策略及其算法

直接配送策略下随机需求库存-路径问题（Stochastic Demand Inventory Routing Problem with Direct Deliveries, SDIRPDD）由于其需求的不确定性、决策的长期性以及其最优策略形式对求解其他库存-路径问题（IRP）的参考价值,使得对SDIPRDD问题的研究成为物流、供应链优化领域研究的一个热点。文章首先证明了无约束SDIRPDD的最优平稳策略为（s,S）形式,并通过分析车辆数约束对客户单阶段期望成本函数的影响,给出了存在车辆数和客户库存容量约束时SDIRPDD问题的最优平稳策略形式,进而提出了一种求解有约束SDIRPDD问题最优平稳策略的近似算法。最后,通过数值算例验证了算法的有效性并分析了结果的现实意义。     

大规模灾害中基于聚类的医疗物资联合运送优化

应急响应中,往往出现救援物资供应节点与需求节点距离太远、关键道路损毁导致难以及时通过车辆运送物资到灾区等情景,此时直升飞机逐渐被用来运送关键应急资源（如医疗物资及医护人员）。然而,大规模灾害中难以使用直升飞机运送医疗物资到每个医疗救助点,通常考虑灾民的聚集性选择一定数量的应急中转点,以接收直升飞机运送的医疗物资,之后采用车辆运送物资到其覆盖的医疗救助点。针对该问题,提出一种基于聚类的两阶段医疗物资联合运输方法：第一阶段根据医疗救助点分布,采用模糊C-均值算法（FCM）进行应急中转点选择和医疗救助点划分,并针对FCM划分中存在的剩余容量不均衡问题,考虑容量约束提出一种改进划分方法（FCMwCC）,构建“直升飞机-车辆”医疗物资联合运输网络结构;第二阶段建立基于聚类的运送路线优化模型,确定从应急中转点到医疗救助点的具体运送路线。数值实验验证了提出方法和算法的有效性。     

面向安全硬约束的煤矿生产物流效率优化研究

在保证安全生产前提下实现效率最大化是煤炭生产企业亟需解决的现实问题。本文结合煤矿生产物流系统的复杂性特征,首先从人员素质、机械装备、环境改善、安全管理、应急救援等方面确定了煤矿生产物流的安全投入指标,运用响应曲面法分析了安全指标与安全水平间的作用关系,确定了煤矿生产物流安全硬约束条件;然后以效率最大化为目标函数、安全目标和资源投入为约束条件,构建了煤矿生产物流效率优化模型;最后通过实例验证了模型的有效性及适用性,为安全生产前提下实现资源优化配置,提高煤矿生产物流效率提供了科学依据。     

基于双层规划的交通疏散中车辆出发与交通控制综合优化

在有组织的区域性疏散中,从需求调节(即疏散车辆出发安排)和供给管理(即交通管控)两方面对疏散交通流进行合理组织,是提高疏散效率的有效途径。论文立足于疏散车辆出发组织与路网交通管控之间的双层决策关系,建立双层规划模型对集结点疏散车辆的发车频率、路线和交叉口控制参数进行综合优化,其中上层模型通过优化信号交叉口的相位绿灯时间即绿信比以降低平均延误,其决策影响到交叉口通行能力等供给特性;下层模型通过优化疏散车辆的分批出发时间与路线以压缩疏散总时间,其决策影响到交叉口流量等需求特性。设计了基于遗产算法的求解步骤,给出了一个数值算例。将模型优化方案和只从交叉口控制参数出发的单方面优化模式所得结果进行了比较,结果表明只从调整绿灯时间着手不结合车辆的出发组织,很难有效降低延误和压缩疏散时间。