This paper introduces a method for optimizing sewer networks using the mixed-integerlinearprogramming (MILP) for a given layout. The objective function is defined as the sum of the costs for pipe purchase, pipe-layi...
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This paper introduces a method for optimizing sewer networks using the mixed-integerlinearprogramming (MILP) for a given layout. The objective function is defined as the sum of the costs for pipe purchase, pipe-laying, and manhole construction expressed in linear terms and subject to minimum and maximum allowable slopes, velocities, and relative depths for both minimum and maximum sewage discharge rates in each pipe. Additionally, provisions are made as constraints or conditions to ensure that a minimum pipe cover is required, that pipe diameters do not decrease in the flow direction, and that pipes maintain a steady elevation at each manhole. All the non-linear constraints are transformed into the linear format. Pipe slope, binary variables accounting for commercial pipe diameters and average implemented depths have also been considered as decision variables. Finally, the performance of the proposed optimization method is evaluated in a benchmark sewer network from the literature.
This paper deals with the Event Scheduling Problem with Consumption and Production of Resources (ESPCPR). ESPCPR is an extension of the Resource Constrained Project Scheduling Problem (RCPSP), where activities requiri...
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This paper deals with the Event Scheduling Problem with Consumption and Production of Resources (ESPCPR). ESPCPR is an extension of the Resource Constrained Project Scheduling Problem (RCPSP), where activities requiring renewable resources arc replaced by events consuming or producing non-renewable resources, the precedence constraints are generalized to define minimal and maximal delays between events and the objective remains the minimization of the makespan. Inspired by previous works on RCPSP, We propose four mixed integer linear programming (MILP) models to solve this problem. Computational results are reported to compare these formulations. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
A wide range of problems can be modeled as mixed integer linear programming (MIP) problems using standard formulation techniques. However, in some cases the resulting MIP can be either too weak or too large to be effe...
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A wide range of problems can be modeled as mixed integer linear programming (MIP) problems using standard formulation techniques. However, in some cases the resulting MIP can be either too weak or too large to be effectively solved by state of the art solvers. In this survey we review advanced MIP formulation techniques that result in stronger and/or smaller formulations for a wide class of problems.
In this paper we report two mixed integer linear programming models to resolve the malleable jobs scheduling problem with single resource. Jobs' release dates and deadlines are taken into account. The total amount...
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ISBN:
(纸本)9783662493908;9783662493892
In this paper we report two mixed integer linear programming models to resolve the malleable jobs scheduling problem with single resource. Jobs' release dates and deadlines are taken into account. The total amount of available resource of the system is variable at different times. Numerical experimentation is conducted to evaluate the performance variability between two introduced models. The objective of this optimization problem is to minimize the total weighted completion time.
Biochar-based systems are a potentially effective means of large-scale carbon sequestration. Such systems rely on carbonization of biomass into biochar, which can then be added to soil for the dual purpose of sequeste...
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Biochar-based systems are a potentially effective means of large-scale carbon sequestration. Such systems rely on carbonization of biomass into biochar, which can then be added to soil for the dual purpose of sequestering carbon and improving fertility. When properly deployed, these systems can potentially achieve negative emissions through the net transfer of carbon from the atmosphere into the ground. In this work, an optimization model is developed to determine the allocation of biochar streams of different quality levels to various biochar sinks, which are farms whose tolerance to impurities present in biochar are known a priori. The optimization model determines source-sink allocation of biochar so as to minimize total system carbon footprint, while ensuring that soil quality parameters for each sink are not exceeded. An illustrative case study is solved to demonstrate the use of the model.
the problem studied in this paper is to allocate and to sequence the elective operation on operating rooms (ORs). We develop a mixed integer linear programming (MILP) model to solve this problem. Decisions in this mod...
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ISBN:
(纸本)9781509018970
the problem studied in this paper is to allocate and to sequence the elective operation on operating rooms (ORs). We develop a mixed integer linear programming (MILP) model to solve this problem. Decisions in this model include the allocation of operations to material resources and human resources, the starting time of them and the starting time for each surgeon. To show the efficiency of this model, we decide to compare it with a constraints programming (CP) approach. The performance of these models is tested using a benchmark of the literature. The results indicate the efficiency of the MILP model compared with the CP model in terms of computational time.
Cellular manufacturing systems (CMS) are production systems that typically comprise a number of manufacturing cells served by a centralized material handling system. Designing such systems includes three major decisio...
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ISBN:
(纸本)9781479978007
Cellular manufacturing systems (CMS) are production systems that typically comprise a number of manufacturing cells served by a centralized material handling system. Designing such systems includes three major decisions;cell formation (CF), group layout (GL), and group scheduling (GS). Traditionally, these three decisions have been dealt with separately, which has usually lead to less than optimal system performance. In this paper, a new mixed integer linear programming (MILP) model is proposed for the integrated CF, GL and GS problem, to efficiently design and operate CMSs. The model solves the integrated problem, taking into consideration intercellular and intracellular transportation times to determine the optimal cell formation, layout of machines and schedule of parts on the machines, simultaneously. Sequence-dependent set up times are also considered in the model. The performance of the model is tested by solving problems previously introduced in the literature considering two objectives;minimizing the makespan or minimizing the mean flow time in the system. The results show that the proposed model is efficient in solving small to medium-sized problems.
This study focuses on the optimal design of district-scale DER (distributed energy resource) systems in which energy is produced outside energy-consuming buildings and sent to the buildings through the energy distribu...
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This study focuses on the optimal design of district-scale DER (distributed energy resource) systems in which energy is produced outside energy-consuming buildings and sent to the buildings through the energy distribution networks. A MILP (mixed integer linear programming) model is constructed. The model can achieve simultaneous optimization of locations (i.e., site for energy generation), synthesis (i.e., type, capacity, and number of equipment as well as structure of the energy distribution networks), and operation strategies of the entire system. The model is built in consideration of discreteness of equipment capacities, equipment partial load operation and output bounds as well as the influence of ambient temperature on gas turbine performance. The objective function is the total annual cost for investing, maintaining, and operating the system. The model is applied to an urban area in Guangzhou (China), and its validity and effectiveness is verified. Results show that the adoption of the proposed DER system provides significant economic benefits in respect to the conventional energy system. (C) 2015 Published by Elsevier Ltd.
In this paper, we model a single elevator scheduling problem as a mixedintegerlinear program (MILP). Based on an industrial prototype model for elevator moving dynamics, the nonlinear travel activities for the eleva...
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ISBN:
(纸本)9781467386838
In this paper, we model a single elevator scheduling problem as a mixedintegerlinear program (MILP). Based on an industrial prototype model for elevator moving dynamics, the nonlinear travel activities for the elevator are linearized in the scheduling problem. We propose a set of cutting planes that accelerate the computation time for solving the MILP for a set of testing cases under different scenarios. For the first time, an exact scheduling model is modeled with MILP, and the elevator moving dynamics model is based on a high-accuracy industrial prototype model. According to the model structure, it can be easily extended to various objectives and can be easily implemented. This model can serve as benchmarks for other approaches in simulation.
The paper presents a mixed integer linear programming (MILP) model for the solution of the three-phase volt/var optimization (WO) of medium voltage unbalanced distribution feeders. The WO of a distribution feeder is a...
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The paper presents a mixed integer linear programming (MILP) model for the solution of the three-phase volt/var optimization (WO) of medium voltage unbalanced distribution feeders. The WO of a distribution feeder is aimed at calculating the most efficient operating conditions by means of the scheduling of transformers equipped with an on-load tap changer and distributed reactive power resources (such as embedded generators and switchable capacitors banks). The proposed model allows the representation of feeders composed by three-phase, two-phase, and single-phase lines, by transformers with different winding connections, by unbalanced wye- and delta-connected loads, by three-phase and single phase capacitor banks and embedded generators. The accuracy of the results is verified by using IEEE test feeders. (C) 2015 Elsevier Ltd. All rights reserved.
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