Multi-cluster environments are composed of multiple clusters of computers that act collaboratively, and thus allowing computational problems to be treated that require more resources than those available in a single c...
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Multi-cluster environments are composed of multiple clusters of computers that act collaboratively, and thus allowing computational problems to be treated that require more resources than those available in a single cluster. However, the degree of complexity of the scheduling process is greatly increased by the heterogeneity of resources and co-allocation process, which distributes the tasks of parallel jobs across cluster boundaries. This work presents a new scheduling strategy that allocates multiple jobs from the system queue simultaneously on a heterogeneous multicluster, by applying co-allocation when is necessary. Our strategy is composed by a job selection function and a linear programming model to find the best allocation for multiple jobs. The proposed scheduling technique is shown to reduce the execution times of the parallel jobs and the overall response times by 38% compared with other scheduling techniques in the literature.
Given a product design and a repair network for capital goods, a level of repair analysis determines for each component in the product (1) whether it should be discarded or repaired upon failure and (2) at which locat...
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Given a product design and a repair network for capital goods, a level of repair analysis determines for each component in the product (1) whether it should be discarded or repaired upon failure and (2) at which location in the repair network to do this. In this paper, we show how the problem can be modelled as a minimum cost flow problem with side constraints. Advantages are that (1) solving our model requires less computational effort than solving existing models and (2) we achieve a high model flexibility, i.e., many practical extensions can be added. Furthermore, we analyse the added value of modelling the exact structure of the repair network, instead of aggregating all data per echelon as is common in the literature. We show that in some cases, cost savings of over 7% can be achieved. We also show when it is sufficient to model the repair network by echelons only, which requires less input data. (C) 2010 Elsevier B.V. All rights reserved.
The problem of distribution centers location with multiple practical constraints, such as soft service time window, rigid work time window, vehicle being reused and so on, is shown firstly. Secondly, a multi-factor in...
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ISBN:
(纸本)9781612842011
The problem of distribution centers location with multiple practical constraints, such as soft service time window, rigid work time window, vehicle being reused and so on, is shown firstly. Secondly, a multi-factor integrated optimization model is given, which not only optimizes distribution centers location and vehicle routes, but also meets all the multiple practical constraints. A bi-level nested genetic algorithm is proposed thirdly, where the design of the lower algorithm meets various constraints of optimization. Finally, the feasibility of the model and the efficiency of the algorithm are tested by a numerical example.
Increasing social awareness together with the new regulations for carbon and waste management are forcing enterprises to reconsider their supply chains with respect to economic, social and environmental objectives. Fu...
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Increasing social awareness together with the new regulations for carbon and waste management are forcing enterprises to reconsider their supply chains with respect to economic, social and environmental objectives. Furthermore, cap and trade legislation for greenhouse gas emissions introduces a new level of complexity. This article presents a comprehensive methodology to address sustainable supply chain design problems where carbon emissions and total logistics costs, including suppliers and sub-contractors selection, technology acquisition and the choice of transportation modes, are considered in the design phase. The proposed methodology provides decision makers with a multi-objective mixed-integer linear programming model to determine the trade-off between economic and environmental considerations. This methodology is illustrated through the study of a Canadian firm operating in the steel industry which is facing a new legislation that caps carbon emissions. The results show how emission trading market can be used to reduce the carbon dioxide abatement cost.
In this paper we propose a genetic algorithm (GA) approach based on a topological sort (TS)-based representation procedure for effectively solving precedence-constrained sequencing problems (PCSPs). The TS-based repre...
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In this paper we propose a genetic algorithm (GA) approach based on a topological sort (TS)-based representation procedure for effectively solving precedence-constrained sequencing problems (PCSPs). The TS-based representation procedure used in the proposed GA approach can generate feasible sequences in PCSPs. By applying the proposed GA approach, the sequence determination problems with precedence constraints can be easily solved. Experimental results show that the proposed GA approach is a good alternative in locating optimal sequence for various types of PCSPs.
In both restructured and vertically integrated power systems, it is desirable to transmit power to remote locations without causing any congestion and consequently avoiding inefficiency in generation dispatch. In this...
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ISBN:
(纸本)9781457710018
In both restructured and vertically integrated power systems, it is desirable to transmit power to remote locations without causing any congestion and consequently avoiding inefficiency in generation dispatch. In this paper, in order to relieve network congestion, transmission switching is employed as a powerful tool to change network topology which consequently yields lower energy prices and higher market efficiently. Here, transmission switching problem is formulated as a DC optimal power flow (DCOPF) problem with binary variables and is solved using mixed integer programming (MIP). In addition, a procedure is presented, which examines the impacts of switching on system security in more details by means of an ACOPF problem. In order to test the feasibility and effectiveness of the method, a 5-bus and the IEEE 14-bus systems have been used. In order to study the impact of switching, a number of system variables have been studied including: generation cost, congestion rent, locational marginal price (LMP), voltage profile and transmission losses. The results demonstrate that transmission switching is able to successfully remove congestion as well as reducing system cost and hence leading to lower energy prices.
This paper discusses the evolution and implementation of smart dispatch tools to support the real-time operation of the PJM competitive wholesale electricity market. These innovations include the implementation of mul...
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ISBN:
(纸本)9781457710018
This paper discusses the evolution and implementation of smart dispatch tools to support the real-time operation of the PJM competitive wholesale electricity market. These innovations include the implementation of multi-stage real-time dispatch software, adaptive generation modeling, enhanced visualization tools and comprehensive evaluation and feedback mechanisms through the perfect dispatch concept. The paper discusses the operational situations and challenges that have driven the need for continued evolution of dispatch tools. The paper explores efficiency gains that the market experienced when these innovations were successfully incorporated into the market clearing and dispatch processes at PJM.
This research deals with the multi-level capacitated lot-sizing problem originating from the production system of a large typical oil refinery. A deterministic mixed integer programming model based on the minimization...
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ISBN:
(纸本)9783037852156
This research deals with the multi-level capacitated lot-sizing problem originating from the production system of a large typical oil refinery. A deterministic mixed integer programming model based on the minimization of setup, production, transportation and inventory costs is formulated to determine the production, inventory and transportation quantities in each time period under complicated material-balance and capacity constraints. A numerical example is subsequently provided to illustrate the broad applicability of the proposed model.
Traditional methods conduct production planning and scheduling separately and solve transfer lot sizing problem between these two steps. Unfortunately, this may result in infeasibility in planning and scheduling. We t...
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ISBN:
(纸本)9783037850046
Traditional methods conduct production planning and scheduling separately and solve transfer lot sizing problem between these two steps. Unfortunately, this may result in infeasibility in planning and scheduling. We take into account transfer lot size in production planning to obtain the consistency and to eliminate the gap between planning and real production. We present the detailed Transfer Lot-Based Model with mixed integer programming. Experiments show that performance measures of a production plan change remarkably with increasing of transfer lot size.
Given a product design and a repair network for capital goods, a level of repair analysis determines for each component in the product (1) whether it should be discarded or repaired upon failure and (2) at which locat...
详细信息
Given a product design and a repair network for capital goods, a level of repair analysis determines for each component in the product (1) whether it should be discarded or repaired upon failure and (2) at which location in the repair network to do this. In this paper, we show how the problem can be modelled as a minimum cost flow problem with side constraints. Advantages are that (1) solving our model requires less computational effort than solving existing models and (2) we achieve a high model flexibility, i.e., many practical extensions can be added. Furthermore, we analyse the added value of modelling the exact structure of the repair network, instead of aggregating all data per echelon as is common in the literature. We show that in some cases, cost savings of over 7% can be achieved. We also show when it is sufficient to model the repair network by echelons only, which requires less input data. (C) 2010 Elsevier B.V. All rights reserved.
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