检索结果-内蒙古大学图书馆

Integrated joint pest management strategies in the presence of control spillovers

EUROPEAN REVIEW OF AGRICULTURAL ECONOMICS 2013年第5期40卷 785-805页

作者： Yigezu, Yigezu A. Alexander, Corinne E. Preckel, Paul V. Maier, Dirk E. Mason, Linda J. Woloshuk, Charles P. Lawrence, John Moog, Dale J. Int Ctr Agr Res Dry Areas Amman Jordan Purdue Univ W Lafayette IN 47907 USA Kansas State Univ Manhattan KS 66506 USA

Integrated pest management has proved cost-effective in coping with crop pests. This article identifies characteristics of pests, controls and economic incentives that may make the development of an integrated joint pest management (IJPM) strategy designed for simultaneous control of multiple pests worthwhile. We demonstrate via a case study that an IJPM strategy may add considerable value for on-farm corn storage. Critical factors for an IJPM strategy are that the pests are affected by the same environmental variables, but with different thresholds and response functions;controls for one pest impact other pests;and the pests have similar economic importance.

关键词： integrated pest management stochastic dynamic programming insect management mould management stored corn

来源：评论

学校读者我要写书评

暂无评论

Optimal dynamic asset allocation strategy for ELA scheme of DC pension plan during the distribution phase

引用

INSURANCE MATHEMATICS & ECONOMICS 2013年第2期52卷 404-410页

作者： He, Lin Liang, Zongxia Renmin Univ China Sch Finance Beijing 100084 Peoples R China Tsinghua Univ Dept Math Sci Beijing 100084 Peoples R China

In this paper, we study the optimal dynamic asset allocation strategy for the ELA scheme of DC pension plan during the distribution phase. In an ELA scheme of DC pension plan, the assets are invested in equities and bonds, and are distributed to the plan participants by an actuarial method. The survived participant can also obtain a survival credit from the mortality risk-sharing implicit in the pension plan. The goal of the scheme is to maintain the stable purchasing power of the plan participants, i.e., to minimize the square deviations of the distribution and a predetermined level by choosing the optimal dynamic asset allocation proportions. We formalize the problem into a continuous-time stochastic optimal control problem and establish the optimal dynamic asset allocation strategy by stochastic dynamic programming method. We obtain the optimal dynamic asset allocation proportions invested in the equities and bonds, and give an economical explanation of the key factors influencing the strategy. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Defined contribution pension plan Equity-linked annuity (ELA) scheme Optimal dynamic asset allocation stochastic dynamic programming HJB equations

来源：评论

学校读者我要写书评

暂无评论

Valuing flexible operating strategies in nickel production under uncertainty 20

Valuing flexible operating strategies in nickel production u...

引用

20th International Congress on Modelling and Simulation (MODSIM)

作者： Bao, C. Mortazavi-Naeini, M. Northey, S. Tarnopolskaya, T. Monch, A. Zhu, Z. CSIRO Computat Informat Minerals Flagship Melbourne Vic Australia CSIRO Proc Sci & Engn Minerals Flagship Melbourne Vic Australia

ISBN: (纸本)9780987214331

With increasing global demand for nickel (which is a key component of stainless steel) the focus of mineral industry is currently on the abundant low-grade nickel laterite reserves. The extraction of nickel from the low-grade laterites is a technically difficult and expensive process and, as a result, the profitability of nickel production projects is highly affected by uncertainty over future market conditions. The project value can be increased by utilizing flexible operating strategies in response to changing future market conditions and Real Options analysis provides a suitable tool for optimizing flexible operating strategies over a long planning horizon in the face of uncertainty. This paper presents the first study on the valuation of flexible operating strategies in a realistic nickel laterite production system under uncertainty of nickel price and exchange rate. In this paper, the production of ore from the three hypothetical nickel laterite mines being fed to a central processing facility is studied. The common features of nickel laterite production, such as a two-fraction (limonite and saprolite) structure of the laterite ore body, layering of each fraction, with different ore grades (concentration of nickel) in each layer, and a simultaneous mining of several ore bodies, are incorporated into the model. It is common in the minerals industry that the ore from each mine is blended to provide as constant a feed rate and grade as possible to the processing facility. However, such a constant feed strategy may not generate the best financial return. In this paper, we investigate whether higher returns can be achieved by adopting a flexible strategy of switching, at prescribed intervals of time, between different feed rates of ore from the three mines that have different quality of nickel laterite. Such flexible strategy allows the operator to change the production rate of nickel in response to changing projected market conditions. In this paper, we use an appr

关键词： Real options stochastic dynamic programming Least Squares Monte Carlo (LSM) nickel laterite multiple mine-site operation genetic algorithm

来源：评论

学校读者我要写书评

暂无评论

Upper and lower bounds for convex value functions of derivative contracts

引用

ECONOMIC MODELLING 2013年 34卷 69-75页

作者： Ben-Ameur, Hatem de Frutos, Javier Fakhfakh, Tarek Diaby, Vacaba HEC Montreal Montreal PQ Canada Univ Valladolid Inst Math IMUVA E-47002 Valladolid Spain FSEG Sfax Sfax Tunisia ISG Tunis Tunis Tunisia

The aim of this paper is to compute upper and lower bounds for convex value functions of derivative contracts. Laprise et al. (2006) compute bounds for American-style vanilla options by selected portfolios of call options. We provide an alternative interpretation of their numerical procedure as a stochastic dynamic program for which the Bellman value function is approximated by selected piecewise linear interpolations at each decision date. The stochastic dynamic program does not (directly) depend on portfolios of call options, but rather on a key ingredient: some transition parameters of the underlying asset. More in line with the literature on dynamic programming, our procedure is contract free and is well designed to accommodate all one-dimensional convex value functions of derivative contracts. In support of this, we revisit the numerical investigation of Laprise et al. (2006) and enlarge their findings to include options embedded in bonds under affine term-structure models of interest rates. (C) 2012 Elsevier B.V. All rights reserved.

关键词： American options Derivative contracts Convex functions Upper and lower bounds stochastic dynamic programming Piecewise linear interpolations

来源：评论

学校读者我要写书评

暂无评论

KALMAN-LIKE STATE TRACKING AND CONTROL IN POMDPS WITH APPLICATIONS TO BODY SENSING NETWORKS

KALMAN-LIKE STATE TRACKING AND CONTROL IN POMDPS WITH APPLIC...

引用

IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Zois, Daphney-Stavroula Levorato, Marco Mitra, Urbashi Univ So Calif Ming Hsieh Dept Elect Enginering Los Angeles CA 90089 USA

ISBN: (纸本)9781479903566

In this paper, the problem of state tracking with controlled observations is considered for a system modeled by a discrete-time, finite-state Markov chain. The system state is 'hidden' and observed via conditionally Gaussian measurements that are shaped by the underlying state and an exogenous control input. Following an innovations approach, a Kalman-like filter is derived to estimate the Markov chain system state. To optimize the control strategy, the associated mean-squared error is used as an optimization criterion for a partially observable Markov Decision Process (POMDP). The optimal solution is determined via stochastic dynamic programming. Numerical results are presented for the application of physical activity detection in heterogeneous, wireless body area networks.

关键词： Markov models approximate MMSE POMDP stochastic dynamic programming innovations approach

来源：评论

学校读者我要写书评

暂无评论

OPTIMAL ALLOCATION OF INVENTORY AND DEMAND FOR MANAGING SUPPLY CHAIN REVENUES

OPTIMAL ALLOCATION OF INVENTORY AND DEMAND FOR MANAGING SUPP...

引用

作者： ABHILASHA KATARIYA Texas A&M University

学位级别：博士

This dissertation focuses on three distinct yet related problems that are motivated by practices of electronics manufacturers, who satisfy stochastic demand from multiple markets and multisource parts from several suppliers. The first problem investigates joint replenish- ment and allocation decisions for a supplier who satisfies stochastic demand from a primary market and a spot market. We formulate the problem as a multi-period stochastic dynamic program and show that the optimal policy is characterized by two quantities: the critical produce-up-to level and the critical retain-up-to level. We establish bounds for these two quantities, discuss their economic interpretation, and use them to construct a new and effec- tive heuristic policy. We identify two practical benchmark policies and establish thresholds on the unit revenue earned from the spot market such that one of the two benchmark poli- cies is optimal. Using a computational study, we quantify the benefits of the optimal policy relative to the benchmark policies and examine the effects of demand correlation. The second problem investigates an important extension where a supplier faces stochas- tic demand from Class 1 along with price-sensitive stochastic demand from Class 2. We investigate the supplier's joint replenishment, allocation and pricing problem by formulating it as a multi-period, two-stage stochastic dynamic program. We show that a dynamic pricing policy is optimal at stage 2, and the stage 1 optimal policy is characterized by two quan- tities: the critical produce-up-to level and the critical amount of inventory to be protected from Class 1. In contrast to the optimal policy, myopic policies are less costly to evaluate, and hence, are more practical. We establish two sufficient conditions under which a myopic joint inventory and pricing policy is optimal. Using a computational study, we show that the benefits of dynamic pricing to Class 2 are higher than the benefits of discretionary sales to

关键词： Inventory/production systems production capacity spot market stochastic dynamic programming dynamic pricing myopic policies replenishment inventory allocation demand allocation bullwhip effect cyclic consumption policy multi-sourcing multiple

来源：评论

学校读者我要写书评

暂无评论

Balancing learning and economies of scale for adaptive clinical trials

引用

OPERATIONS RESEARCH FOR HEALTH CARE 2013年第3期2卷 42-51页

作者： Fleischhacker, Adam J. Zhao, Yao Univ Delaware Dept Business Adm Newark DE 19716 USA State Univ New Jersey Rutgers Univ Dept Supply Chain Management & Mkt Sci Newark NJ 07102 USA

Prior to the start of an adaptive clinical trial, demand for an investigational drug can be highly uncertain. Treatment length, recommended dosages, and forecasted patient recruitment can fluctuate in response to early trial results. While initial demand forecasts can be very wrong, the factors influencing future demand can be learned during the trial. To take advantage of this learning, intra-trial production and/or packaging can be leveraged, but this is done at the expense of scale economies. In this paper, we study the balance between learning and economies of scale for adaptive clinical trials. We characterize the optimal production (or packaging) decisions and through analytical and numerical studies, we develop insights on the impact of fixed costs, learning rates in terms of forecasting future demand, inventory overage costs, and inventory underage costs on the value of having intra-trial flexibility and on decisions regarding quantity and timing of drug supply. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Clinical trial supply stochastic dynamic programming Production planning

来源：评论

学校读者我要写书评

暂无评论

Maintenance Centered Service Parts Inventory Control

Maintenance Centered Service Parts Inventory Control

引用

作者： Willem van Jaarsveld Erasmus University Rotterdam

学位级别：master

High-tech capital goods enable the production of many services and articles that have become a part of our daily lives. Examples include the refineries that produce the gasoline we put in our cars, the photolithography systems that enable the production of the chips in our cell phones and laptops, the trains and railway infrastructure that facilitate public transport and the aircraft that permit us to travel long distances. To prevent costly production disruptions of such systems when failures occur, it is crucial that service parts are readily available to replace any failed parts. However, service parts represent significant investments and failures are unpredictable, so it is unclear which parts should be stocked and in what quantity. In this thesis, analytical models and solution methods are developed to aid companies in making this decision. Amongst other things, we analyze systems in which multiple parts need replacement after a failure, a situation that is frequently encountered in practice. This affects the ability to complete repairs in a timely fashion. We develop new modeling techniques in order to successfully apply scalable deterministic approaches, such as column generation techniques and sample average approximation methods, to this stochastic problem. This leads to solution techniques that, unlike traditional methods, can ensure that all parts needed to complete maintenance are readily available. The approach is capable of meeting the challenging requirements of a real-life repair shop.

关键词： ATO systems Column Generation Intermittent Demand Forecasting Inventory control Obsolescence Redundancy Service parts Spare parts stochastic dynamic programming stochastic programming

来源：评论

学校读者我要写书评

暂无评论

Expected Future Value Decomposition Based Bid Price Generation for Large-Scale Network Revenue Management

引用

TRANSPORTATION SCIENCE 2013年第2期47卷 181-197页

作者： Escudero, L. F. Monge, J. F. Morales, D. Romero Wang, J. Univ Rey Juan Carlos Dept Estadist & Invest Operativa Madrid Spain Univ Miguel Hernandez Ctr Invest Operativa Elche Alicante Spain Univ Oxford Said Business Sch Oxford England

This paper studies a multistage stochastic programming (SP) model for large-scale network revenue management. We solve the model by means of the so-called expected future value (EFV) decomposition via scenario analysis, estimating the impact of the decisions made at a given stage on the objective function value related to the future stages. The EFV curves are used to define bid prices on bundles of resources directly, as opposed to the traditional additive approach. We compare our revenues to those obtained by additive bid prices, such as the bid prices derived from the deterministic equivalent model (DEM) of the compact representation of the SP model. Our computational experience shows that the revenues obtained by our approach are better for middle-range values of the load factor of demand, whereas the differences among all the approaches we have tested are insignificant for extreme values. Moreover, our approach requires significantly less computation time than does the optimization of DEM by plain use of optimization engines. Problem instances with 72 pairs of bundle-fare classes have been solved in less than one minute, with 800 pairs in less than five minutes, and with 4,000 pairs in less than one hour. The time taken by DEM was, in general, of one order of magnitude higher. Finally, for the three largest problem instances, and after two hours, the expected revenue returned by DEM was below that obtained by EFV by 13.47%, 17.14%, and 38.94%, respectively.

关键词： network revenue management scenario trees stochastic dynamic programming expected future value curves nonadditive bid prices load factor of demand

来源：评论

学校读者我要写书评

暂无评论

Joint Production and Preventive Maintenance Strategy for Manufacturing Systems With stochastic Demand

引用

JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME 2013年第3期135卷 031016-031016页

作者： Jin, Xiaoning Ni, Jun Univ Michigan Dept Mech Engn Ann Arbor MI 48109 USA

This paper seeks to make joint decisions on preventive maintenance level and production quantity for manufacturing systems subject to stochastic demand in a finite-horizon. Standard models for scheduling preventive maintenance typically ignore the throughput target variation due to demand uncertainty and specify instead a constant demand rate. We show that maintenance decisions should be integrated with production decisions to accommodate the demand uncertainty. To achieve this objective, preventive maintenance (PM) flexibility is introduced as the opportunity to select and implement maintenance tasks at different levels, which can be viewed as real options to the manufacturer. PM levels can be defined according to the degree to which the machine condition is stored by maintenance. A preventive maintenance can be a minimal, imperfect, or perfect one. By leveraging PM flexibility, this paper proposes a model to determine optimal production quantity and PM level for a single-product manufacturing system with a finite planning horizon. A real option analysis (ROA) is developed to quantify the benefits and costs of PM flexibility. We derive optimal joint decisions for maintenance and production that maximize the overall expected profit of the system. We compare the proposed PM-flexible model with the conventional PM-fixed model in a case study. The results demonstrate the condition that the PM-flexible model outperforms the PM-fixed model in terms of option value (expected operating profits). We also show how the growth in demand volatility affects the optimal decisions and overall profitability. These results have important implications for making maintenance and production decisions, especially in industries that feature high demand volatility.

关键词： real option analysis flexibility preventive maintenance stochastic dynamic programming

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：