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integer-programming
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An efficient multiple-stage mathematical programming method for advanced single and multi-floor facility layout problems
, Article Applied Mathematical Modelling ; Volume 40, Issue 9-10 , 2016 , Pages 5605-5620 ; 0307904X (ISSN) ; Akbari Jokar, M. R ; Sharif University of Technology
Elsevier Inc
2016
Abstract
Single floor facility layout problem (FLP) is related to finding the arrangement of a given number of departments within a facility; while in multi-floor FLP, the departments should be imbedded in some floors inside the facility. The significant influence of layout design on the effectiveness of any organization has turned FLP into an important issue. This paper presents a three- (two-) stage mathematical programming method to find competitive solutions for multi- (single-) floor problems. At the first stage, the departments are assigned to the floors through a mixed integer programming model (the single floor version does not require this stage). At the second stage, a nonlinear programming...
Preemptive multi-skilled resource investment project scheduling problem: mathematical modelling and solution approaches
, Article Computers and Chemical Engineering ; Volume 96 , 2017 , Pages 55-68 ; 00981354 (ISSN) ; Afshar Nadjafi, B ; Akhavan Niaki, S. T ; Sharif University of Technology
Abstract
Many chemical production systems encounter with a functionally flexible workplace which need multi-skilled workers. This research integrates the multi-skilled project scheduling problem with the resource investment problem which aims to obtain concurrent optimal policy of project scheduling and skills’ recruitment. The objective of the proposed model is minimization of total recruitment cost for different levels of the skills. An integer programming formulation is developed for the problem, and it is validated through solving several small scale instances using the GAMS software. To tackle real-life problem scales, a genetic-based and a particle-swarm-based algorithm with calibrated...
Designing a multi-service healthcare network based on the impact of patients’ flow among medical services
, Article OR Spectrum ; Volume 40, Issue 3 , 2018 , Pages 637-678 ; 01716468 (ISSN) ; Eshghi, K ; Sharif University of Technology
Springer Verlag
2018
Abstract
Efficient location of medical services is an issue of paramount importance in healthcare strategic planning. In this research, a mathematical model is developed for the location of multi-service health centers, assuming probabilistic demand and service time. Since patients may be shifted to another service after receiving a service by doctors’ order, health system is considered a Jackson queueing network. We assume that patients have “probabilistic choice behavior” and the primary factors contributing to their choice of one center over another are their proximity to the center and the number of medical services offered by the center. The proposed mixed integer nonlinear programming model...
Some relations between rank of a graph and its complement
, Article Linear Algebra and Its Applications ; Volume 422, Issue 1 , 2007 , Pages 341-347 ; 00243795 (ISSN) ; Alipour, A ; Ebrahimi Boroojeni, J ; Ghorbani, E ; Mirjalalieh Shirazi, M ; Sharif University of Technology
2007
Abstract
Let G be a graph of order n and rank(G) denotes the rank of its adjacency matrix. Clearly, n ≤ rank (G) + rank (over(G, -)) ≤ 2 n. In this paper we characterize all graphs G such that rank (G) + rank (over(G, -)) = n, n + 1 or n + 2. Also for every integer n ≥ 5 and any k, 0 ≤ k ≤ n, we construct a graph G of order n, such that rank (G) + rank (over(G, -)) = n + k. © 2006 Elsevier Inc. All rights reserved
Solving Multi-objective Integer Optimization Problems by Using Benders Decomposition Method
, M.Sc. Thesis Sharif University of Technology ; Eshghi, Kourosh (Supervisor)
Abstract
Real-world decision-making problems usually have several criteria for evaluating the performance of alternatives. On the other hand, mathematical programming is a very practical tool for modeling and solving decision-making problems and multi-objective mathematical programming has high importance among researchers and managers in this field of study. However, the field of multi-objective integer programming is considered a rigorous category. Methods for solving these types of problems can be divided into three different approaches. There are few approaches and methods for solving multi-objective mixed-integer optimization problems in litreture.In this research, an extension of benders...
Observability of hybrid AC/DC power systems with variable-cost PMUs
, Article IEEE Transactions on Power Delivery ; Vol. 29, issue. 1 , February , 2014 , p. 345-352 ; ISSN: 8858977 ; Fotuhi-Firuzabad, M ; Safdarian, A ; Shahidehpour, M ; Sharif University of Technology
Abstract
The integration of high-voltage direct-current (dc) transmission lines in conventional alternating-current (ac) systems would affect the indirect measurement of phasor measurement unit (PMU) devices since the concept of phasors would not correspond to dc transmission circuits. The optimal PMU placement problem in ac/dc systems subjected to the system observability is presented in this paper by applying a mixed-integer programming model. In practice, the cost of each PMU is variable as a function of PMU measurement channels. This attribute is incorporated in the proposed model as well. In addition, the number of PMU measurement channels is deemed to be technically limited; thus, the common...
A stochastic framework for short-term operation of a distribution company
, Article IEEE Transactions on Power Systems ; Volume 28, Issue 4 , 2013 , Pages 4712-4721 ; 08858950 (ISSN) ; Fotuhi Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
2013
Abstract
This paper presents a stochastic framework for short-term operation of a distribution company (disco). The proposed framework optimizes disco's operational decisions in two hierarchical stages. The first stage, called day-ahead operation stage (DAOS), deals with the operational decisions on purchases from the day-ahead market and commitment of distributed generation (DG) units. The objective of this stage is to minimize the expected operating cost while the financial risk exposed by uncertain real-time prices and loads is restricted to a given level. The model associated with this stage is based on the mixed-integer programming (MIP) format. The second stage, named real-time operation stage...
A new concept of adjacency for concurrent consideration of economic and safety aspects in design of facility layout problems
, Article Journal of Loss Prevention in the Process Industries ; Volume 40 , 2016 , Pages 603-614 ; 09504230 (ISSN) ; Ghassemi Tari, F ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this manuscript a new phenomenon of adjacency and closeness rating is proposed for constructing the optimal facility layout design. In the proposed approach, the closeness rating is applied to every pair of neighboring departments in a range of their attached point up to a predefined distance between them. Also, while in the traditional approach the closeness rating is applied for determining either the proximity or farness of two departments, the proposed approach considers both the degree of closeness as the economical purposes, and farness as the safety purposes concurrently. A mathematical model is proposed for constructing the optimal layout design. For evaluating the efficiency and...
Generation expansion and retirement planning based on the stochastic programming
, Article Electric Power Systems Research ; Volume 104 , November , 2013 , Pages 138-145 ; 03787796 (ISSN) ; Aminifar, F ; Fotuhi Firuzabad, M ; Sharif University of Technology
Abstract
This paper develops a mathematical model based on the stochastic programming for simultaneous generation expansion and retirement planning. Retirement decision of the existing generating units is accommodated since these units are aging more and more. The proposed method is formulated as an optimization problem in which the objective function is to minimize the expected total cost consisting of the investment required for commissioning new units, operation and maintenance costs, the retirement salvage cost, and the system risk cost. The problem is subjected to a set of generating unit and system physical and operational constraints. The modeling of energy limited units is also devised in a...
Cloud manufacturing service selection optimization and scheduling with transportation considerations: mixed-integer programming models
, Article International Journal of Advanced Manufacturing Technology ; 2017 , Pages 1-28 ; 02683768 (ISSN) ; Houshmand, M ; Van Woensel, T ; Mutlu, N ; Sharif University of Technology
Abstract
Cloud manufacturing is an emerging service-oriented manufacturing paradigm that integrates and manages distributed manufacturing resources through which complex manufacturing demands with a high degree of customization can be fulfilled. The process of service selection optimization and scheduling (SSOS) is an important issue for practical implementation of cloud manufacturing. In this paper, we propose new mixed-integer programming (MIP) models for solving the SSOS problem with basic composition structures (i.e., sequential, parallel, loop, and selective). Through incorporation of the proposed MIP models, the SSOS with a mixed composition structure can be tackled. As transportation is...
Optimal placement of sectionalizing switch considering switch malfunction probability
, Article IEEE Transactions on Smart Grid ; 2017 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
Abstract
Sectionalizing switches (SSs) are often presumed to function fully reliable. However, SSs are exposed to have some malfunctions, whereby undermining their ability to improve service reliability. This study presents a model to integrate SS malfunction probability into SS placement problem. The model aims to minimize the total SSs costs as well as customers interruption cost. The proposed model is formulated in mixed integer programing (MIP), which can be easily solved via several available solvers and gain global optimal solution. The proposed model indicates the extent to which the placement problem is affected by uncertainty associated with SSs functionality, and how not considering SSs...
Sectionalizing switch placement in distribution networks considering switch failure
, Article IEEE Transactions on Smart Grid ; 2018 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
Abstract
Sectionalizing switches play a crucial role in enhancing service reliability to the end users of distribution networks. However, they might encounter failures, thereby causing interruptions in the networks. The existing switch placement models consider only the pros of switches in improving service reliability, while they fail to deem switches cons in possible failures and thus increasing system interruptions. This study intends to show the importance of switch failure in the switch placement problem and the extent to which switch failure alters the switches allocation in a network. To do so, we develop a novel model based on mixed integer programming format to integrate the impacts of...
Deployment of fault indicator in distribution networks: a MIP-based approach
, Article IEEE Transactions on Smart Grid ; Volume 9, Issue 3 , May , 2018 , Pages 2259-2267 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Fault indicator (FI) plays a crucial rule in enhancing service reliability in distribution systems. This device brings substantial benefits for fault management procedure by speeding up fault location procedure. This paper intends to develop a new optimization model to optimally deploy FI in distribution systems. The proposed model aims to consider a tradeoff between the total customer interruption cost and FI relevant costs, including capital investment, installation, and maintenance costs. As the main contribution of this paper, the problem is formulated in mixed integer programing, which guarantees global optimum solution achieved in an effective runtime. Moreover, the model takes...
Computational load reduction in model predictive control of nonlinear systems via decomposition
, Article 5th International Conference on Control, Instrumentation, and Automation, ICCIA 2017, 21 November 2017 through 23 November 2017 ; Volume 2018-January , 2018 , Pages 216-221 ; 9781538621349 (ISBN) ; Rastgar, M ; Haeri, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
The aim of this study is to reduce the computational load in model predictive control of multi-input nonlinear systems. First, the nonlinear system which has a high number of states and inputs is decomposed into several subsystems by solving a linear integer programming problem offline. Then, the model of each subsystem is revised by considering the effect of coupling and interactions of other subsystems. Next, the robust model predictive technique based on linear matrix inequalities is employed to compute control signal for each subsystem. An industrial chemical reaction example is used to illustrate the effectiveness of the proposed method. © 2017 IEEE
Component and mode models for the short-term scheduling of combined-cycle units
, Article IEEE Transactions on Power Systems ; Volume 24, Issue 2 , 2009 , Pages 976-990 ; 08858950 (ISSN) ; Shahidehpour, M ; Li, Z ; Fotuhi Firuzabad, M ; Sharif University of Technology
2009
Abstract
We propose a component model for the scheduling of combined-cycle gas turbine (CCGT) units by mixed-integer programming (MIP) in which combustion turbines (CTs) and steam turbines (STs) are modeled as individual units. The hourly schedule of CCGT based on the component model is compared with that of the mode model. The modeling of modes, which includes a combination of CTs and STs, would require certain approximations for representing fuel input-power output curves, ramping rate limits, minimum operating time limits, etc. The approximations can result in sub-optimal schedules. Furthermore, the commitment and dispatch of CCGTs based on the mode model will require a real-time dispatch to...
Unit commitment with probabilistic spinning reserve and interruptible load considerations
, Article IEEE Transactions on Power Systems ; Volume 24, Issue 1 , 2009 , Pages 388-397 ; 08858950 (ISSN) ; Fotuhi Firuzabad, M ; Shahidehpour, M ; Sharif University of Technology
2009
Abstract
This paper demonstrates how a probabilistic criterion could be explicitly integrated in the unit commitment (UC) formulation. Both spinning reserve and interruptible load are taken into account as the operating reserve facilities. Incorporating the interruption notice time of interruptible load involves some complexities in the evaluation procedure and problem formulation which is considered in this paper. The expected energy not supplied (EENS) is considered as a probabilistic criterion and a new method is proposed to calculate this index in the presence of interruptible load. The reliability-constrained unit commitment (RCUC) problem is formulated based on the mixed-integer programming...
Optimal placement of sectionalizing switch considering switch malfunction probability
, Article IEEE Transactions on Smart Grid ; Volume 10, Issue 1 , 2019 , Pages 403-413 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Sectionalizing switches (SSs) are often presumed to function fully reliable. However, SSs are exposed to have some malfunctions, whereby undermining their ability to improve service reliability. This paper presents a model to integrate SS malfunction probability into SS placement problem. The model aims to minimize the total SSs costs as well as customers interruption cost. The proposed model is formulated in mixed integer programing, which can be easily solved via several available solvers and gain global optimal solution. The proposed model indicates the extent to which the placement problem is affected by uncertainty associated with SSs functionality, and how not considering SSs...
Optimal placement of protective and controlling devices in electric power distribution systems: a MIP model
, Article IEEE Access ; Volume 7 , 2019 , Pages 122827-122837 ; 21693536 (ISSN) ; Safdarian, A ; Moeini Aghtaie, M ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
This paper presents a mathematical model for simultaneous deployment of protective devices (PDs) and controlling devices (CDs) in distribution networks. The PDs include fuses and reclosers and the CDs are remote controlled switches (RCSs) and manual switches (MSs). The model is to minimize equipment costs as well as sustained and momentary interruption costs. It considers the coordination of fuses and reclosers during temporary faults involving fuse saving and fuse blowing schemes. The model is in mixed integer programming (MIP) fashion which can be effectively solved with available solvers. The performance of the proposed model is verified through applying it to Bus 4 of Roy Billinton test...
Optimal placement of sectionalizing switch considering switch malfunction probability
, Article IEEE Transactions on Smart Grid ; Volume 10, Issue 1 , 2019 , Pages 403-413 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Sectionalizing switches (SSs) are often presumed to function fully reliable. However, SSs are exposed to have some malfunctions, whereby undermining their ability to improve service reliability. This paper presents a model to integrate SS malfunction probability into SS placement problem. The model aims to minimize the total SSs costs as well as customers interruption cost. The proposed model is formulated in mixed integer programing, which can be easily solved via several available solvers and gain global optimal solution. The proposed model indicates the extent to which the placement problem is affected by uncertainty associated with SSs functionality, and how not considering SSs...
Optimal placement of protective and controlling devices in electric power distribution systems: A MIP Model
, Article IEEE Access ; Volume 7 , 2019 , Pages 122827-122837 ; 21693536 (ISSN) ; Safdarian, A ; Moeini Aghtaie, M ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
This paper presents a mathematical model for simultaneous deployment of protective devices (PDs) and controlling devices (CDs) in distribution networks. The PDs include fuses and reclosers and the CDs are remote controlled switches (RCSs) and manual switches (MSs). The model is to minimize equipment costs as well as sustained and momentary interruption costs. It considers the coordination of fuses and reclosers during temporary faults involving fuse saving and fuse blowing schemes. The model is in mixed integer programming (MIP) fashion which can be effectively solved with available solvers. The performance of the proposed model is verified through applying it to Bus 4 of Roy Billinton test...