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The contribution of heat storage to the profitable operation of combined heat and power plants in liberalized electricity markets

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ENERGY 2012年第1期41卷 75-82页

作者： Christidis, Andreas Koch, Christoph Pottel, Lothar Tsatsaronis, George Tech Univ Berlin Inst Energy Engn D-10587 Berlin Germany Vottenfall Europe Warme AG D-12435 Berlin Germany

Combined heat and power (CHP) plants are characterized by high fuel efficiency and are therefore usually the thermal power producing units of choice within a district heating network. The operation of CHP units is typically controlled by the current heat demand and thus delimits the range of electricity production. Heat storage devices are a promising alternative to uncouple the heat load of the district heating network from the commitment of the units and to allow for price-oriented electricity production. In this paper we present numerical results for the combined optimization of the operation of nineteen existing power plant units and the design of six proposed heat accumulators which supply the district heating network of Berlin. A mixed-integer programming problem (MIP) is formulated in GAMS and solved with CPLEX. This paper focuses on the potential for increasing profitability through the addition of heat accumulators in the energy system described above, on the optimal storage capacities for different price scenarios (variation of fuel costs, prices for carbon dioxide emission certificates, and electricity price time series) as well as on the adjustment of the operation of the power plants due to heat storage. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Combined heat and power plants District heating Heat storage Design optimization Unit commitment mixed-integer programming

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Exact methods for the quay crane scheduling problem when tasks are modeled at the single container level

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COMPUTERS & OPERATIONS RESEARCH 2018年 99卷 218-233页

作者： Msakni, Mohamed Kais Diabat, Ali Rabadi, Ghaith Al-Salem, Mohamed Kotachi, Mariam Qatar Univ Dept Mech & Ind Engn Doha Qatar New York Univ Abu Dhabi Div Engn Abu Dhabi 129188 U Arab Emirates NYU Tandon Sch Engn Dept Civil & Urban Engn Brooklyn NY 11201 USA Old Dominion Univ Dept Engn Management & Syst Engn Norfolk VA 23529 USA

The scheduling of quay cranes (QCs) to minimize the handling time of a berthed vessel is one of the most important operations in container terminals as it impacts the terminal's overall productivity. In this paper, we propose two exact methods to solve the quay crane scheduling problem (QCSP) where a task is defined as handling a single container and subject to different technical constraints including QCs' safety margin, non-crossing, initial position, and nonzero traveling time. The first method is based on two versions of a compact mixed-integer programming formulation that can solve large problem instances using a general purpose solver. The second is a combination of some constraints of the proposed mathematical model and the binary search algorithm to reduce the CPU time, and solve more efficiently large-sized problems. Unlike existing studies, the computational study demonstrates that both methods can reach optimal solutions for large-sized instances and validates their dominance compared to an exact model proposed in the literature which finds solutions only for small problems. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Scheduling Container terminals Quay crane scheduling problem mixed-integer programming

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Resource-constrained project scheduling with concave processing rate functions

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JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY 2015年第5期66卷 794-806页

作者： Steeneek, Daniel W. Sarin, Subhash C. Virginia Tech Blacksburg VA 24061 USA

In this paper, we address a resource-constrained project scheduling problem involving a single resource. The resource can be applied at varying consumption rates to the activities of the project. The duration of each activity is defined by a convex, non-increasing time-resource trade-off function. In addition, activities are not preemptable (ie, the resource consumption rate of an activity cannot be altered while the activity is being processed). We explicitly consider variation of the rate at which an activity is performed with variation in resource consumption rate. We designate the number of units (amount of an activity) performed per unit time with variation in resource consumption rate as the processing rate function, and assume this function to be concave. We present a tree-search-based method in concert with the solution of a nonlinear program and the use of dominance properties to determine: (i) the sequence in which to perform the activities of the project, and (ii) the resource consumption rate to allocate to each activity so as to minimize the project duration (makespan). We also present results of an experimental investigation that reveal the efficacy of the proposed methodology Finally, we present an application of this methodology to a practical setting.

关键词： project scheduling project management mixed-integer programming non-linear programming

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Scheduling of waterways with tide and passing box

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NAVAL RESEARCH LOGISTICS 2022年第4期69卷 609-621页

作者： Nehrke, Lara Schulz, Arne Univ Hamburg Inst Operat Management Moorweidenstr 18 D-20148 Hamburg Germany

Due to the increasing amount of goods transported by vessels and the resulting increased size of the vessels, waterway scheduling becomes a challenging task. Waterways can often only be expanded with enormous costs and environmental damage. Therefore, this paper investigates a scheduling problem on a restricted waterway. Wide vessels are only allowed to pass in a passing box and vessels with deep draught can only pass the waterway in a time window around high tide. We present a mixed-integer program (MIP) for the problem setting and develop techniques which allow us to fix variables and reduce the number of variables and constraints of the model. The resulting model formulations are evaluated in a comprehensive computational study on a real-world setting at the river Elbe next to Hamburg (Germany).

关键词： mixed-integer programming passing box tide-dependent waterway vessel scheduling

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MIP formulations for an application of project scheduling in human resource management

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FLEXIBLE SERVICES AND MANUFACTURING JOURNAL 2018年第4期30卷 609-639页

作者： Rihm, Tom Trautmann, Norbert Zimmermann, Adrian Univ Bern Dept Business Adm Bern Switzerland Univ Bern Quantitat Methods Business Adm Bern Switzerland

In the literature, various discrete-time and continuous-time mixed-integer linear programming (MIP) formulations for project scheduling problems have been proposed. The performance of these formulations has been analyzed based on generic test instances. The objective of this study is to analyze the performance of discrete-time and continuous-time MIP formulations for a real-life application of project scheduling in human resource management. We consider the problem of scheduling assessment centers. In an assessment center, candidates for job positions perform different tasks while being observed and evaluated by assessors. Because these assessors are highly qualified and expensive personnel, the duration of the assessment center should be minimized. Complex rules for assigning assessors to candidates distinguish this problem from other scheduling problems discussed in the literature. We develop two discrete-time and three continuous-time MIP formulations, and we present problem-specific lower bounds. In a comparative study, we analyze the performance of the five MIP formulations on four real-life instances and a set of 240 instances derived from real-life data. The results indicate that good or optimal solutions are obtained for all instances within short computational time. In particular, one of the real-life instances is solved to optimality. Surprisingly, the continuous-time formulations outperform the discrete-time formulations in terms of solution quality.

关键词： OR in the service industries Human resource management Project scheduling mixed-integer programming Comparative analysis

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An exact algorithm for robust influence maximization

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MATHEMATICAL programming 2020年第1-2期183卷 419-453页

作者： Nannicini, Giacomo Sartor, Giorgio Traversi, Emiliano Calvo, Roberto Wolfler IBM TJ Watson Res Ctr Yorktown Hts NY 10598 USA SINTEF Digital Oslo Norway Univ Sorbonne Paris Nord LIPN CNRS UMR 7030 F-93430 Villetaneuse France Univ Cagliari Dept Math & Comp Sci Cagliari Italy

We propose a Branch-and-Cut algorithm for the robust influence maximization problem. The influence maximization problem aims to identify, in a social network, a set of given cardinality comprising actors that are able to influence the maximum number of other actors. We assume that the social network is given in the form of a graph with node thresholds to indicate the resistance of an actor to influence, and arc weights to represent the strength of the influence between two actors. In the robust version of the problem that we study, the node thresholds and arc weights are affected by uncertainty and we optimize over a worst-case scenario within given robustness budgets. We study properties of the robust solution and showthat even computing theworst-case scenario for given robustness budgets is NP-hard. We implement an exact Branch-and-Cut as well as a heuristic Branch-Cut-and-Price. Numerical experiments show that we are able to solve to optimality instances of size comparable to other exact approaches in the literature for the non-robust problem, and we can tackle the robust version with similar performance. On larger instances (= 2000 nodes), our heuristic Branch-Cutand-Price significantly outperforms a 2-opt heuristic. An extended abstract of this paper appeared in the proceedings of IPCO 2019.

关键词： Influence maximization mixed-integer programming Robust optimization

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Using integer programming to refine Lagrangian-based unit commitment solutions

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IEEE TRANSACTIONS ON POWER SYSTEMS 2000年第1期15卷 151-156页

作者： Takriti, S Birge, JR IBM Corp Thomas J Watson Res Ctr Dept Math Sci Yorktown Heights NY 10598 USA Univ Michigan Dept Ind & Operat Engn Ann Arbor MI 48109 USA

We develop a technique for refining the unit commitment solution obtained from solving the Lagrangian. Our model is an integer program with nonlinear constraints. It can be solved to optimality using branch-and-bound.... 详细信息

关键词： branch-and-bound dynamic programming Lagrangian relaxation mixed-integer programming unit commitment

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Time-Indexed Formulations for the Runway Scheduling Problem

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TRANSPORTATION SCIENCE 2017年第4期51卷 1196-1209页

作者： Avella, Pasquale Boccia, Maurizio Mannino, Carlo Vasilyev, Igor Univ Sannio Dipartimento Ingn I-82100 Benevento Italy SINTEF Informat & Commun Technol N-0373 Oslo Norway Russian Acad Sci Matrosov Inst Syst Dynam & Control Theory Siberian Branch Irkutsk 664033 Russia

The problem of sequencing and scheduling airplanes landing and taking off on a runway is a major challenge for air traffic management. This difficult real-time task is still carried out by human controllers, with little help from automatic tools. Several methods have been proposed in the literature, including mixed-integer programming (MlP)-based approaches. However, there is an opinion that MIP is unattractive for real-time applications, since computation times are likely to grow too large. In this paper, we reverse this claim, by developing a MIP approach able to solve to optimality real-life instances from congested airports in the stringent times allowed by the application. To achieve this, it was mandatory to identify new classes of strong valid inequalities, along with developing effective fixing and lifting procedures.

关键词： air traffic management runway scheduling problem single-machine scheduling mixed-integer programming valid inequalities fixing and lifting procedures

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An assignment-sequencing methodology for scheduling assembly and test operations with multi-pass requirements

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IIE TRANSACTIONS 2015年第2期47卷 153-172页

作者： Gao, Zhufeng Bard, Jonathan F. Chacon, Rodolfo Stuber, John Univ Texas Austin Ind Engn & Operat Res Program Austin TX 78712 USA Texas Instruments Inc Dallas TX 75243 USA

This article presents a three-phase methodology for scheduling assembly and test operations for semiconductor devices. The facility in which these operations are performed is a re-entrant flow shop consisting of several dozen to several hundred machines and up to a 1000 specialized tools. The semiconductor devices are contained in lots, and each lot follows a specific route through the facility, perhaps returning to the same machine multiple times. Each step in the route is referred to as a "pass." In the first phase of the methodology an extended assignment model is solved to simultaneously assign tooling and lots to the machines. Four prioritized objectives are considered: minimize the weighted sum of key device shortages, maximize the weighted sum of lots processed, minimize the number of machines used, and minimize the makespan. In the second phase, lots are optimally sequenced on their assigned machines using the same prioritized objectives. Due to the precedent relations induced by the pass requirements, some lots may have to be delayed or removed from the assignment model solution to ensure that no machine runs beyond the planning horizon. In the third phase, machines are reset to allow additional lots to be processed when tooling is available. The methodology was tested using data provided by the Assembly and Test facility of a leading manufacturer. The results indicate that high-quality solutions can be obtained within 1hour when compared with those obtained with a greedy randomized adaptive search procedure. Cost reductions were observed across all objectives and averaged 62% in the aggregate.

关键词： assembly and test operations Re-entrant flow semiconductor manufacturing mixed-integer programming assignment model

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Quantitative insights into the integrated supply vehicle routing and production planning problem

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INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS 2016年 177卷 66-76页

作者： Hein, Fanny Almeder, Christian European Univ Viadrina Frankfurt Oder Chair Supply Chain Management Grosse Scharrnstr 59 D-15230 Frankfurt Germany

In this work we assess the benefits of an integrated planning approach for the supply of raw material and the subsequent production process. The supply part is concerned with the collection of raw materials from geographically dispersed suppliers, while the production planning part addresses the conversion of those raw materials into final products to satisfy customer demand. The proposed model is an extension of the model introduced by Kuhn and Liske (2011) considering dynamic demand and general structures of the bill of materials. We investigate two scenarios: one including raw material inventories at the production site, and the other supposing just-in-time (JIT) supply. Numerical experiments show that substantial cost savings are possible with an integrated planning approach compared to a classical sequential approach. The JIT scenario and situations with a rather low utilization in the production system benefit most from the integration. The proposed supply vehicle routing and production planning problem has a reverse structure unlike the well-studied production-distribution systems. Surprisingly, a sensitivity analysis on the dependency of the cost savings on different parameters show a quite similar behavior for both types of planning problems. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Integrated planning Supply-production planning Vehicle routing Just-in-time mixed-integer programming

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