This paper focus on the routing, modulation level and spectrum allocation (RMLSA) problem in the next generation datacentre networks, which own the advantages of both Elastic Optical Networks (EON) and Software Define...
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This paper focus on the routing, modulation level and spectrum allocation (RMLSA) problem in the next generation datacentre networks, which own the advantages of both Elastic Optical Networks (EON) and Software Defined Networking (SDN). We proposes an integerlinearprogramming (ILP) model for this problem. Simulation results show the ILP model achieves an outstanding load balancing performance.
Particle swarm optimization (PSO) originated from bird flocking models. It has become a popular research field with many successful applications. In this paper, we present a scheme of an aggregate production planning ...
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Particle swarm optimization (PSO) originated from bird flocking models. It has become a popular research field with many successful applications. In this paper, we present a scheme of an aggregate production planning (APP) from a manufacturer of gardening equipment. It is formulated as an integer linear programming model and optimized by PSO. During the course of optimizing the problem, we discovered that PSO had limited ability and unsatisfactory performance, especially a large constrained integral APP problem with plenty of equality constraints. In order to enhance its performance and alleviate the deficiencies to the problem solving, a modified PSO (MPSO) is proposed, which introduces the idea of sub-particles, a particular coding principle, and a modified operation procedure of particles to the update rules to regulate the search processes for a particle swarm. In the computational study, some instances of the APP problems are experimented and analyzed to evaluate the performance of the MPSO with standard PSO (SPSO) and genetic algorithm (GA). The experimental results demonstrate that the MPSO variant provides particular qualities in the aspects of accuracy, reliability, and convergence speed than SPSO and GA. (C) 2013 Elsevier Ltd. All rights reserved.
In this article, we propose a model based on 0-1 linearprogramming for automatically determining a transactional composite web service (CWS) from a service dependency graph that optimizes a QoS measure. The QoS measu...
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ISBN:
(纸本)9783662453919;9783662453902
In this article, we propose a model based on 0-1 linearprogramming for automatically determining a transactional composite web service (CWS) from a service dependency graph that optimizes a QoS measure. The QoS measure used in this model can be either a classical weighted sum of QoS criteria or a minmax-type criterion (e.g. response time). The transactional properties are a set of rules that ensures a reliable execution of the resulting CWS. The proposed 0-1 linear program is solved using a standard solver (CPLEX). Our experiments show that this new exact model surpasses two main related approaches: an approximate one based on transactional requirements and an exact one, based on 0-1 linearprogramming (LP), but not dealing with transactional properties. In a large majority of the test sets used for our experiments, our model finds a better solution more rapidly than both related approaches and is able to guarantee its optimality. Moreover, our model is able to find the optimal solutions of big size test sets, as the ones proposed by the Web Service Challenge 2009.
In this paper, we present two approaches to solve the relocation problem in one-way carsharing system. We start by formulating the problem as an integer linear programming model. Then using mobility data collected fro...
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ISBN:
(纸本)9781479944972
In this paper, we present two approaches to solve the relocation problem in one-way carsharing system. We start by formulating the problem as an integer linear programming model. Then using mobility data collected from an operational carsharing system, we built demands matrices that will be used as input data for our solver. We notice that the time needed to solve the ILP using an exact solver increases dramatically when we increase the number of employees involved in the relocation process and when the system gets bigger. To cope with this problem, we develop a greedy algorithm in order to solve the relocation problem in a faster time. Our algorithm takes one second to solve the relocation problem in worst cases;also, we evaluated the robustness of the two approaches with stochastic input data using different numbers of employees.
In this study, a mathematical programmingmodel is proposed for scheduling problem of nurses' labor shifts. The developed mathematical programmingmodel's aim is to minimize nurses' total idle waiting time...
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In this study, a mathematical programmingmodel is proposed for scheduling problem of nurses' labor shifts. The developed mathematical programmingmodel's aim is to minimize nurses' total idle waiting time during a week planning horizon. In this model, investigated constraints are as follows: (1) Maximum total working time a week for each nurse must not be exceeded. (2) After a nurse works a shift, the nurse can be assigned to another shift after two shifts at least. This constraints-set ensures resting of the nurse after the nurse works a shift. (3) Total number of nurses worked for each shift must be controlled with maximum and minimum bounds given for number of nurses for each shift. In this manner, total number of nurses worked for each shift is between maximum and minimum limit-values given for each shift. This constraint ensures flexibility to the user to determine number of nurses for each shift. (4) The decision variable that shows nurse-shift assignment pairs is 0 or 1. In this study, maximum total working time a week for a nurse, total number of nurses in a health service, maximum and minimum numbers of nurses worked a shift are user-specified parameters. In this way, this model can be adapted for the studies with different values of these parameters. In this study, the developed model is illustrated using a numerical example and then LINGO8.0 software is used to ensure the global optimum solution of the developed model. Results and also sensitivity analysis carried out for this example are presented in the study.
This paper proposes a more realistic multi-period liner ship fleet planning problem for liner container shipping company than has been studied in previous literature. The proposed problem is formulated as a scenario-b...
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This paper proposes a more realistic multi-period liner ship fleet planning problem for liner container shipping company than has been studied in previous literature. The proposed problem is formulated as a scenario-based dynamic programmingmodel consisting of a number of integerlinearprogramming formulations for each single planning period, and the model can be solved efficiently by a shortest path algorithm on an acyclic network. A numerical example is carried out to illustrate the applicability of the proposed model and solution method. The numerical results show that chartering in ships may not always be a better policy for a long-term planning horizon though it is much cheaper than buying ships in the short-term. Purchasing ships seems to be a more profitable investment in the long run. (C) 2010 Elsevier Ltd. All rights reserved.
Cellular manufacturing represents an effective and even more applied alternative in production system organization especially when line or batch-type production is not economically convenient or technically feasible. ...
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Cellular manufacturing represents an effective and even more applied alternative in production system organization especially when line or batch-type production is not economically convenient or technically feasible. This is particularly true when a wide range of quite similar items need to be produced in small lot sizes with frequent and expensive setups. Cellular manufacturing is supported by the so-called cell formation problem whose aim is forming part groups to be assigned to manufacturing cells, composed by a defined subset of machines, so that the sum of intercellular flow costs and direct intra-cell costs is minimized. An effective approach to form manufacturing cells is based on cluster analysis and on the evaluation of similarity coefficients: machines are grouped by the application of clustering techniques and finally parts are assigned to clusters. The aim of this paper is to present a hybrid and original procedure for the cell formation problem based on cluster analysis and integerlinearprogramming. In particular, an integer linear programming model optimizes and re-arranges the configuration of the cells as the result of the application of a hierarchical clustering algorithm. The proposed model evaluates the possibility of duplicating a machine in one or more cells in order to reach the best trade-off between direct cell costs and indirect costs caused by intercellular flows. As a result, all work areas are correctly designed with the optimal number of machines of each type and total production system cost is quantified. The presentation and discussion of the proposed approach is supported by the illustration of a significant case study which takes inspiration from the literature.
System-on-chip (SOC) designs comprised of a number of embedded cores are widespread in today's integrated circuits. Embedded core-based design is likely to be equally popular for three-dimensional integrated circu...
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System-on-chip (SOC) designs comprised of a number of embedded cores are widespread in today's integrated circuits. Embedded core-based design is likely to be equally popular for three-dimensional integrated circuits (3D ICs), the manufacture of which has become feasible in recent years. 3D integration offers a number of advantages over traditional 2D technologies, such as the reduction in the average interconnect length, higher performance, lower interconnect power consumption and smaller IC footprint. Despite recent advances in 3D fabrication and design methods, no attempt has been made thus far to design a 1500-style test wrapper for an embedded core that spans multiple layers in a 3D SOC. This study addresses wrapper optimisation in 3D ICs based on through-silicon vias (TSVs) for vertical interconnects. The authors objective is to minimise the scan-test time for a core under constraints on the total number of TSVs available for testing. The authors present an optimal solution based on an integer linear programming model as well as two polynomial-time heuristic solutions. Simulation results are presented for embedded cores from the ITC 2002 SOC test benchmarks.
On-demand digital printing is an example of emerging personalized manufacturing services. It provides unique opportunities to automate the printing process, enhance productivity, and better utilize resources such as e...
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ISBN:
(纸本)9781457704345
On-demand digital printing is an example of emerging personalized manufacturing services. It provides unique opportunities to automate the printing process, enhance productivity, and better utilize resources such as equipment, servers and IT infrastructure. In this work, we present a unified solution approach to solve an important optimization problem in digital printing, viz., simultaneous mapping of component tasks of a print job to time steps (scheduling), selection of resources for these tasks, and mapping of tasks to resources (binding). We model print jobs, the relationships between them, and dependencies between tasks within a job, in terms of sequencing graphs. This formal representation is then used for scheduling and resource binding. The optimization objective is to enable just-in-time manufacturing, that is, to minimize both the slack time (the duration between the delivery deadline and the completion time of the order) and the opportunity cost for job orders. The proposed approach uses genetic algorithms (GA) to systematically search the space of feasible solutions. The fitness function of the GA is carefully crafted to match the optimization objective. An integerlinearprogramming (ILP) model is described to evaluate the GA heuristic by deriving optimal solutions for small problem instances. The optimization technique is further evaluated using print orders from a commercial print service provider and compared to baseline methods commonly implemented in the industrial settings.
In this paper, we focus on solving the problem of removing inter-core communication overhead for streaming applications on chip multiprocessors. The objective is to totally remove inter-core communication overhead whi...
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ISBN:
(纸本)9780769542980
In this paper, we focus on solving the problem of removing inter-core communication overhead for streaming applications on chip multiprocessors. The objective is to totally remove inter-core communication overhead while minimizing the overall memory usage. By totally removing inter-core communication overhead, a shorter period can be applied and system throughput can be improved. Our basic idea is to let tasks with intra-period data dependencies transform to inter-period data dependencies so as to overlap the execution of computation and inter-core communication tasks. To solve the problem, we first perform analysis and obtain the bounds of the times needed to reschedule each task. Then we formulate the scheduling problem as an integerlinearprogramming (ILP) model and obtain an optimal schedule. We perform simulations on a set of benchmarks from both real-life streaming applications and synthetic task graphs. The simulation results show that the proposed approach can achieve significant reduction in schedule length and improve the memory usage compared with the previous work.
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