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A branch and price algorithm for the minimum power multicasting problem in wireless sensor networks

MATHEMATICAL METHODS OF OPERATIONS RESEARCH 2011年第3期74卷 327-342页

作者： Montemanni, R. Leggieri, V. Ist Dalle Molle Studi Intelligenza Artificial IDS CH-6928 Manno Switzerland Free Univ Bozen Bolzano Fac Comp Sci I-39100 Bolzano Italy

The Minimum Power Multicast Problem arises in wireless sensor networks and consists in assigning a transmission power to each node of a network in such a way that the total power consumption over the network is minimized, while a source node is connected to a set of destination nodes, toward which a message has to be sent periodically. A new mixed integer programming model for the problem, based on paths, is presented. A practical exact algorithm based on column generation and branch and price is derived from this model. A comparison with state-of-the-art exact methods is presented, and it is shown that the new approach compares favorably to other algorithms when the number of destination nodes is moderate. Under this condition, the proposed method is able to solve previously unmanageable instances.

关键词： Minimum power topology Wireless networks mixed integer linear programming Column generation Branch and price

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Challenges and models in supporting logistics system design for dedicated-biomass-based bioenergy industry

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BIORESOURCE TECHNOLOGY 2011年第2期102卷 1344-1351页

作者： Zhu, Xiaoyan Li, Xueping Yao, Qingzhu Chen, Yuerong Univ Tennessee Dept Ind & Informat Engn Knoxville TN 37996 USA Univ Akron Dept Mech Engn Akron OH 44325 USA

This paper analyzed the uniqueness and challenges in designing the logistics system for dedicated biomass-to-bioenergy industry, which differs from the other industries, due to the unique features of dedicated biomass (e.g., switchgrass) including its low bulk density, restrictions on harvesting season and frequency, content variation with time and circumambient conditions, weather effects, scattered distribution over a wide geographical area, and so on. To design it, this paper proposed a mixed integer linear programming model. It covered from planting and harvesting switchgrass to delivering to a biorefinery and included the residue handling, concentrating on integrating strategic decisions on the supply chain design and tactical decisions on the annual operation schedules. The present numerical examples verified the model and demonstrated its use in practice. This paper showed that the operations of the logistics system were significantly different for harvesting and non-harvesting seasons, and that under the well-designed biomass logistics system, the mass production with a steady and sufficient supply of biomass can increase the unit profit of bioenergy. The analytical model and practical methodology proposed in this paper will help realize the commercial production in biomass-to-bioenergy industry. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Logistics analysis Switchgrass Biomass-to-bioenergy Supply chain mixed integer linear programming

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On electrical load tracking scheduling for a steel plant

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COMPUTERS & CHEMICAL ENGINEERING 2011年第12期35卷 3044-3047页

作者： Hait, Alain Artigues, Christian Univ Toulouse Inst Super Aeronaut & Espace F-31055 Toulouse France CNRS LAAS F-31077 Toulouse 4 France Univ Toulouse UPS INSA INPISAEUT1UTMLAAS F-31077 Toulouse 4 France

Nolde and Morari (2010) study a steel manufacturing scheduling problem where the tasks must be scheduled such that electricity consumption matches to a pre-specified periodic energy chart. They propose a continuous time integer linear programming formulation to solve the problem. In this note, we present an alternative continuous time formulation, focused on the relative positions of tasks and time periods, that improves significantly the computation time. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Steel plant mixed integer linear programming Load tracking

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mixed integer linear models for the optimization of dynamical transport networks

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MATHEMATICAL METHODS OF OPERATIONS RESEARCH 2011年第3期73卷 339-362页

作者： Geissler, Bjoern Kolb, Oliver Lang, Jens Leugering, Guenter Martin, Alexander Morsi, Antonio Univ Erlangen Nurnberg Dept Math D-91058 Erlangen Germany Tech Univ Darmstadt Dept Math D-64293 Darmstadt Germany

We introduce a mixed integer linear modeling approach for the optimization of dynamic transport networks based on the piecewise linearization of nonlinear constraints and we show how to apply this method by two examples, transient gas and water supply network optimization. We state the mixed integer linear programs for both cases and provide numerical evidence for their suitability.

关键词： mixed integer linear programming Piecewise linear approximation Gas network optimization Water network optimization

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On Ex Post Pricing in the Real-Time Electricity Market

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IEEE TRANSACTIONS ON POWER SYSTEMS 2011年第1期26卷 153-164页

作者： Zheng, Tongxin Litvinov, Eugene ISO New England Inc Holyoke MA 01040 USA

This paper proposes a new framework in calculating the ex post prices for the spot electricity market. The proposed method finds a set of prices that are as consistent as possible with the actual outputs of resources correctly following their dispatch instructions. Two alternative consistency metrics are proposed in the paper. One measures the difference between the actual performance of an individual resource and its bid-based profit-maximizing response to the ex post prices in a perfectly competitive market. Another measures the difference between the ex post price and the price that supports the actual response of an individual resource. Compared to the existing approaches adopted in the real-time electricity markets in the U. S., the proposed method solves the ex post energy and ancillary service prices directly and simultaneously. It does not require heuristics that are hard to justify, and has a much clear definition for the pricing problem than the existing approaches do. Moreover, the proposed approach is flexible in the price control required by the market operators. Numerical examples are presented to further demonstrate the validity of this approach.

关键词： Ancillary service co-optimization ex ante pricing ex post pricing locational marginal pricing mixed integer linear programming power systems spot electricity market

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Optimal design and global sensitivity analysis of biomass supply chain networks for biofuels under uncertainty

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COMPUTERS & CHEMICAL ENGINEERING 2011年第9期35卷 1738-1751页

作者： Kim, Jinkyung Realff, Matthew J. Lee, Jay H. Georgia Inst Technol Sch Chem & Biomol Engn Atlanta GA 30332 USA Korea Adv Inst Sci & Technol Dept Chem & Biomol Engn Taejon 305701 South Korea

Bio-fuels represent promising candidates for renewable liquid fuels. One of the challenges for the emerging industry is the high level of uncertainty in supply amounts, market demands, market prices, and processing technologies. These uncertainties complicate the assessment of investment decisions. This paper presents a model for the optimal design of biomass supply chain networks under uncertainty. The uncertainties manifest themselves as a large number of stochastic model parameters that could impact the overall profitability and design. The supply chain network we study covers the Southeastern region of the United States and includes biomass supply locations and amounts, candidate sites and capacities for two kinds of fuel conversion processing, and the logistics of transportation from the locations of forestry resources to the conversion sites and then to the final markets. To reduce the design problem to a manageable size the impact of each uncertain parameter on the objective function is computed for each end of the parameter's range. The parameters that cause the most change in the profit over their range are then combined into scenarios that are used to find a design through a two stage mixed integer stochastic program. The first stage decisions are the capital investment decisions including the size and location of the processing plants. The second stage recourse decisions are the biomass and product flows in each scenario. The objective is the maximization of the expected profit over the different scenarios. The robustness and global sensitivity analysis of the nominal design (for a single nominal scenario) vs. the robust design (for multiple scenarios) are analyzed using Monte Carlo simulation over the hypercube formed from the parameter ranges. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Biorefinery Supply chain networks Uncertainty Robustness mixed integer linear programming Global sensitivity analysis

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Redispatching Active and Reactive Powers Using a Limited Number of Control Actions

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IEEE TRANSACTIONS ON POWER SYSTEMS 2011年第3期26卷 1221-1230页

作者： Capitanescu, Florin Wehenkel, Louis Univ Liege Dept Elect Engn & Comp Sci B-4000 Liege Belgium

This paper deals with some essential open questions in the field of optimal power flow (OPF) computations, namely: the limitation of the number of controls allowed to move, the trade-off between the objective function and the number of controls allowed to move, the computation of the minimum number of control actions needed to satisfy constraints, and the determination of the sequence of control actions to be taken by the system operator in order to achieve its operation goal. To address these questions, we propose approaches which rely on the computation of sensitivities of the objective function and inequality constraints with respect to control actions. We thus determine a subset of controls allowed to move in the OPF, by solving a sensitivity-based mixed integer linear programming (MILP) problem. We study the performances of these approaches on three test systems (of 60, 118, and 618 buses) and by considering three different OPF problems important for a system operator in emergency and/or in normal states, namely the removal of thermal congestions, the removal of bus voltage limits violation, and the reduction of the active power losses.

关键词： mixed integer linear programming nonlinear programming optimal power flow

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Modeling the machine configuration and line-balancing problem of a PCB assembly line with modular placement machines

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INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2011年第1-4期54卷 349-360页

作者： Rong, Aiying Toth, Attila Nevalainen, Olli S. Knuutila, Timo Lahdelma, Risto Univ Turku Dept Informat Technol Turku 20014 Finland Univ Turku TUCS Turku 20014 Finland Univ Szeged Juhasz Gyula Fac Educ Szeged Hungary Aalto Univ Dept Energy Technol Aalto 00076 Finland

This paper studies the combined task of determining a favorable machine configuration and line balancing (MCLB) for an assembly line where a single type of printed circuit board is assembled by a set of interconnected, reconfigurable machine modules. The MCLB problem has been solved previously by heuristic methods. In the present work, we give a mathematical formulation for it and transform the model into a linear integer programming model that can be solved using a standard solver for problems of moderate size. The model determines the best machine configuration and allocation of components to the machine modules with the objective of minimizing the cycle time. Because the solutions found in this way are globally optimal, they can be used to evaluate the efficiency of previous heuristics designed for the MCLB problem. In our experiments, an evolutionary algorithm gave near optimal results.

关键词： Printed circuit board assembly Reconfigurable machine modules Line balancing integer programming mixed integer linear programming

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MILP model for emergy optimization in EIP water networks

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CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY 2011年第5期13卷 703-712页

作者： Taskhiri, Mohammad Sadegh Tan, Raymond R. Chiu, Anthony S. F. De La Salle Univ Ctr Engn & Sustainable Dev Res Manila Philippines De La Salle Univ Dept Ind Engn Manila Philippines

The eco-industrial park (EIP) concept provides a framework in which several plants can cooperate with each other and exchange their wastewater to minimize total freshwater consumption. Emergy analysis is a methodology that considers the total, cumulative energy which has been consumed within a system;thus, by minimizing emergy, an environmentally optimal EIP can be designed. This article presents a mixed-integer linear programming (MILP) model for minimizing emergy of an interplant water network in an EIP. The methodology accounts for the environmental impacts of water use, energy consumption, and capital goods within the EIP in a balanced manner. The proposed technique is then demonstrated by solving a case study from literature.

关键词： Emergy Eco-industrial park mixed integer linear programming Water reuse network

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Joint Optimal Relay Selection and Power Allocation in Multicast Cooperative Networks

Joint Optimal Relay Selection and Power Allocation in Multic...

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IEEE International Conference on Communications

作者： Mohammad Faisal Uddin Chadi Assi Ali Ghrayeb Concordia University

ISBN: (纸本)9781457720529

We investigate the joint problem of relay selection and optimal sharing of relay power in wireless cellular networks with multicast traffic. We use two different performance metrics to maximize the network performance. We first present a mixed Boolean-convex optimization model to maximize the overall network capacity and solve this combinatorial problem optimally using branch and bound technique. We then show that obtaining the optimal solution is computationally not feasible for large network sizes and, unlike the case of unicast traffic, a water filling method does not yield near optimal solutions in multicast scenarios. We thus adopt an algorithm based on sequential fixing which substantially reduces the computation time and achieves near optimal solutions. In addition, we present a mixed integer linear programming model to maximize the capacity of the minimum capacity link and show that the model is very efficient to reach the optimal solutions.

关键词： optimal solution mixed integer linear programming power splitting Multicast network capacity relay computational time branch-and-bound techniques Cellular networks Maximize Performance metrics

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