检索结果-内蒙古大学图书馆

dynamic multi-appointment patient scheduling for radiation therapy

EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2012年第2期223卷 573-584页

作者： Saure, Antoine Patrick, Jonathan Tyldesley, Scott Puterman, Martin L. Univ British Columbia Sauder Sch Business Vancouver BC V6T 1Z2 Canada Univ Ottawa Telfer Sch Management Ottawa ON K1N 6N5 Canada British Columbia Canc Agcy Vancouver BC V5Z 4E6 Canada

Seeking to reduce the potential impact of delays on radiation therapy cancer patients such as psychological distress, deterioration in quality of life and decreased cancer control and survival, and motivated by inefficiencies in the use of expensive resources, we undertook a study of scheduling practices at the British Columbia Cancer Agency (BCCA). As a result, we formulated and solved a discounted infinite-horizon Markov decision process for scheduling cancer treatments in radiation therapy units. The main purpose of this model is to identify good policies for allocating available treatment capacity to incoming demand, while reducing wait times in a cost-effective manner. We use an affine architecture to approximate the value function in our formulation and solve an equivalent linear programming model through column generation to obtain an approximate optimal policy for this problem. The benefits from the proposed method are evaluated by simulating its performance for a practical example based on data provided by the BCCA. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Patient scheduling OR in health services Markov decision processes Linear programming approximate dynamic programming

来源：评论

学校读者我要写书评

暂无评论

Computing Near-Optimal Policies in Generalized Joint Replenishment

引用

INFORMS JOURNAL ON COMPUTING 2012年第1期24卷 148-164页

作者： Adelman, Daniel Klabjan, Diego Univ Chicago Booth Sch Business Chicago IL 60637 USA Northwestern Univ Dept Ind Engn & Management Sci Evanston IL 60208 USA

We provide a practical methodology for solving the generalized joint replenishment (GJR) problem, based on a mathematical programming approach to approximate dynamic programming. We show how to automatically generate a value function approximation basis built upon piecewise-linear ridge functions by developing and exploiting a theoretical connection with the problem of finding optimal cyclic schedules. We provide a variant of the algorithm that is effective in practice, and we exploit the special structure of the GJR problem to provide a coherent, implementable framework.

关键词： approximate dynamic programming piecewise-linear ridge functions generalized joint replenishment

来源：评论

学校读者我要写书评

暂无评论

State partitioning based linear program for stochastic dynamic programs: An invariance property

引用

OPERATIONS RESEARCH LETTERS 2012年第6期40卷 487-491页

作者： Park, M. Krishnamoorthy, K. Darbha, S. Chandler, P. Pachter, M. Infoscitex Corp Technol Solut Div Dayton OH 45431 USA Texas A&M Univ Dept Mech Engn College Stn TX 77843 USA USAF Res Lab Control Design & Anal Branch Wright Patterson AFB OH 45433 USA USAF Inst Technol Dept Elect Engn Wright Patterson AFB OH 45433 USA

A common approximate dynamic programming method entails state partitioning and the use of linear programming, i.e., the state-space is partitioned and the optimal value function is approximated by a constant over each partition. By minimizing a positive cost function defined on the partitions, one can construct an upper bound for the optimal value function. We show that this approximate value function is independent of the positive cost function and that it is the least upper bound, given the partitions. (C) 2012 Elsevier B.V. All rights reserved.

关键词： approximate dynamic programming Linear programming State aggregation

来源：评论

学校读者我要写书评

暂无评论

Satisficing vs exploring when learning a constrained environment

Satisficing vs exploring when learning a constrained environ...

引用

6th International Conference on Soft Computing and Intelligent Systems (SCIS) / 13th International Symposium on Advanced Intelligence Systems (ISIS)

作者： Shervais, Stephen Shannon, Thaddeus T. Eastern Washington Univ Coll Business & Publ Adm Cheney WA 99004 USA Portland State Univ Syst Sci Program Portland OR 97207 USA

ISBN: (纸本)9781467327435;9781467327428

Satisficing is an efficient strategy for applying existing knowledge in a complex, constrained, environment. We present a set of agent-based simulations that demonstrate a higher payoff for satisficing strategies than for exploring strategies when using approximate dynamic programming methods for learning complex environments. In our constrained learning environment, satisficing agents outperformed exploring agent by approximately six percent, in terms of the number of tasks completed.

关键词： component satisficing approximate dynamic programming Q learning agent-based simulation

来源：评论

学校读者我要写书评

暂无评论

Virtual Generators: Simplified Online Power System Representations for Wide-Area Damping Control

Virtual Generators: Simplified Online Power System Represent...

引用

General Meeting of the IEEE-Power-and-Energy-Society

作者： Molina, Diogenes Liang, Jiaqi Harley, Ronald G. Venayagamoorthy, Ganesh Kumar Georgia Inst Technol Intelligent Power Infrastruct Consortium Dept Elect & Comp Engn Atlanta GA 30332 USA Univ KwaZulu Natal Durban South Africa Clemson Univ Holcombe Dept Elect & Comp Engn Clemson SC 29634 USA

ISBN: (纸本)9781467327299

This paper introduces a new concept called a Virtual Generator (VG). VGs are simplified representations of groups of coherent synchronous generators in a power system. They resemble commonly used power system dynamic equivalents obtained via generator aggregation techniques. Traditionally power system dynamic equivalents are developed offline, fixed, and used to replace large portions of the system that are considered external to the portion of the system being analyzed in detail. In contrast, VGs are calculated online, are not limited to representing external areas of the system being analyzed/controlled, and do not replace any portion of the power system. Instead, they allow wide-area damping controllers (WADCs) to exploit the realization that a group of coherent synchronous generators in a power system can be controlled as a single generating unit for achieving wide-area damping control objectives. The implementation of VGs is made possible by the availability of Wide-Area Measurements (WAMs) from Phasor Measurement Units (PMUs). To the authors' knowledge, this is the first time that the use of power system equivalencing techniques has been extended to real-time WADC. Simulation studies carried out on the 68-bus New England/New York power system demonstrate that intelligent controllers developed using VGs can significantly improve the stability of a power system by effectively damping low-frequency interarea oscillations.

关键词： virtual generator power system stabilizer wide-area control power system equivalents intelligent control approximate dynamic programming adaptive critic designs generator coherency interarea oscillations

来源：评论

学校读者我要写书评

暂无评论

Optimal Control of Unknown Discrete-Time Nonlinear Systems with Constrained Inputs Using GDHP Technique

Optimal Control of Unknown Discrete-Time Nonlinear Systems w...

引用

31st Chinese Control Conference

作者： Liu Derong Wang Ding Li Hongliang Chinese Acad Sci Inst Automat State Key Lab Management & Control Complex Syst Beijing 100190 Peoples R China

ISBN: (纸本)9789881563811

The adaptive dynamic programming (ADP) approach is employed to design an optimal controller for unknown discrete-time nonlinear systems with control constraints. First, a neural network is constructed to identify the unknown dynamical system with stability proof. Then, the iterative ADP algorithm is developed to solve the optimal control problem with convergence analysis. Moreover, two other neural networks are introduced to approximate the cost function and its derivative and the control law, under the framework of globalized dual heuristic programming technique. Finally, two simulation examples are included to verify the theoretical results.

关键词： Adaptive dynamic programming approximate dynamic programming Control constraints Neural networks Optimal control System identification

来源：评论

学校读者我要写书评

暂无评论

Demand Side Management of Electric Vehicles with Uncertainty on Arrival and Departure Times

Demand Side Management of Electric Vehicles with Uncertainty...

引用

3rd IEEE PES International Conference and Exhibition on Innovative Smart Grid Technologies Europe (ISGT Europe)

作者： Ruelens, Frederik Vandael, Stijn Leterme, Willem Claessens, Bert J. Hommelberg, Maarten Holvoet, Tom Belmans, Ronnie Katholieke Univ Leuven Dept Elect Engn ESAT ELECTA Kasteelpk Arenberg 10Bus 2445 B-3001 Louvain Belgium Katholieke Univ Leuven Dept Comp Sci B-3001 Leuven Belgium Energy Dept Flemish Inst technol Res VITO B-2400 Mol Belgium

ISBN: (纸本)9781467325950;9781467325967

Uncertainty on arrival and departure times makes the scheduling of plug-in hybrid electric vehicles an intrinsically stochastic optimization problem. To take the stochastic nature of this problem into consideration, a scalable stochastic optimization strategy has been formulated. Generally, stochastic programming methods are computationally demanding and become impractical for large-scale problems. This work reduced the dimensionality of the scheduling problem with techniques from approximate dynamic programming. To illustrate the advantage of the stochastic algorithm a deterministic method has been formulated. Compared to the deterministic method, the proposed stochastic method can help an aggregator to reduce its expensive peak charging or avoid penalties for not fully charging the batteries of its clients.

关键词： approximate dynamic programming demand side management stochastic optimization

来源：评论

学校读者我要写书评

暂无评论

Neural-Network-Based Optimal Control for Discrete-Time Nonlinear Systems Using General Value Iteration

Neural-Network-Based Optimal Control for Discrete-Time Nonli...

引用

31st Chinese Control Conference

作者： Li Hongliang Liu Derong Wang Ding Chinese Acad Sci Inst Automat State Key Lab Management & Control Complex Syst Beijing 100190 Peoples R China

ISBN: (纸本)9789881563811

In this paper, we propose a novel adaptive dynamic programming (ADP) scheme based on general value iteration to obtain near optimal control for discrete-time nonlinear systems with continuous state and control space. First, the selection of initial value function is different from the traditional value iteration, and a new method is introduced to demonstrate the convergence property and convergence speed of the value function. Then, the control law obtained at each iteration can stabilize the system under some conditions. At last, three neural networks with Levenberg-Marquardt training algorithm are used to approximate the unknown nonlinear system, the value function and the optimal control law. One simulation example is presented to demonstrate the effectiveness of the present scheme.

关键词： Adaptive dynamic programming approximate dynamic programming optimal control value iteration neural networks reinforcement learning

来源：评论

学校读者我要写书评

暂无评论

A New Optimal Control Method for Discrete-Time Nonlinear Systems with Approximation Error

A New Optimal Control Method for Discrete-Time Nonlinear Sys...

引用

10th World Congress on Intelligent Control and Automation (WCICA)

作者： Wei, Qinglai Liu, Derong Chinese Acad Sci Inst Automat State Key Lab Management & Control Complex Syst Beijing 100190 Peoples R China

ISBN: (纸本)9781467313988

In this paper, a new optimal control method is proposed for discrete-time nonlinear systems based on iterative adaptive dynamic programming (ADP) algorithm with approximation error. In each iteration of the proposed algorithm, the iterative control law and iterative performance index function cannot be accurately obtained. The convergence conditions of the iterative ADP algorithm are presented. According to the convergence conditions, the iterative performance index functions are proved to be convergent to a small neighborhood of the optimal performance index function. Finally, a simulation example is given to illustrate the performance of the proposed method.

关键词： Adaptive dynamic programming approximate dynamic programming discrete-time systems optimal control convergence conditions

来源：评论

学校读者我要写书评

暂无评论

Finite-Horizon Neural Optimal Tracking Control for a Class of Nonlinear Systems with Unknown dynamics

Finite-Horizon Neural Optimal Tracking Control for a Class o...

引用

10th World Congress on Intelligent Control and Automation (WCICA)

作者： Wang, Ding Liu, Derong Li, Hongliang Chinese Acad Sci Inst Automat State Key Lab Management & Control Complex Syst Beijing 100190 Peoples R China

ISBN: (纸本)9781467313988

A neural-network-based finite-horizon optimal tracking control scheme for a class of unknown nonlinear discrete-time systems is developed. First, the tracking control problem is converted into designing a regulator for the tracking error dynamics under the framework of finite-horizon optimal control theory. Then, with convergence analysis in terms of cost function and control law, the iterative adaptive dynamic programming algorithm is introduced to obtain the finite-horizon optimal controller to make the cost function close to its optimal value within an g-error bound. Furthermore, in order to implement the algorithm via dual heuristic dynamic programming technique, three neural networks are employed to approximate the error dynamics, the cost function, and the control law, respectively. In addition, a numerical example is given to demonstrate the validity of the present approach.

关键词： Adaptive dynamic programming approximate dynamic programming finite-horizon optimal tracking control intelligent control neural networks

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：