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scheduling
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A bi-objective model for scheduling of multiple projects under multi-skilled workforce for distributed load energy usage
, Article Operational Research ; Volume 22, Issue 3 , 2022 , Pages 2245-2280 ; 11092858 (ISSN) ; Afshar Nadjafi, B ; Taghi Akhavan Niaki, S ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Satisfying the clients' uncompromising priorities is a challenge for decision makers of organizations that face multiple projects. This paper considers an organization with a multi-skilled workforce working on several predetermined projects under time-of-use energy tariffs where distributed load energy usage is the primary concern of energy suppliers. This paper also considers different time-of-use energy tariffs, which are among the most common strategies to reach a more balanced energy utilization. The problem is stated as a bi-objective mixed-integer programming model containing two conflicting objectives; to minimize the total cost of the multi-skilled workforce and obtain a sustainable...
Evaluating the impact of operation scheduling methods on microgrid reliability using monte carlo simulation
, Article 30th International Conference on Electrical Engineering, ICEE 2022, 17 May 2022 through 19 May 2022 ; 2022 , Pages 670-675 ; 9781665480871 (ISBN) ; Jooshaki, M ; Abbaspour, A ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This paper provides a general methodology for evaluating the reliability of microgrids embedding conventional and renewable energy sources (RESs), as well as energy storage systems (ESSs). The developed reliability assessment model is then leveraged to investigate the impact of different resource scheduling methods on the reliability. The technique applied in this article to assess microgrid reliability is based on the sequential Monte Carlo simulation. In this approach, the coincidence of faults is considered, aside from the annual generation pattern of RESs, i.e., wind and photovoltaic, and the network load profiles. For the sake of considering priority of the microgrid loads, two...
A novel straightforward unit commitment method for large-scale power systems
, Article IEEE Transactions on Power Systems ; Volume 22, Issue 4 , 2007 , Pages 2134-2143 ; 08858950 (ISSN) ; Khodaei, A ; Aminifar, F ; Sharif University of Technology
2007
Abstract
In this paper, a novel fast straightforward method for thermal generating units scheduling is presented. The new method decomposes the solution of the unit commitment (UC) problem into three subproblems. In the first subproblem, the quadratic cost functions of units are linearized and hourly optimum solution of UC is obtained considering all constraints except the minimum up/down time constraints. In the second subproblem, the minimum up/down times are enforced through a novel optimization process by modifying the schedule obtained in the first step. Finally, in the third subproblem, the extra reserve is minimized using a new decommitment algorithm. For testing the proposed method, the...
Bicriteria two-machine flowshop scheduling using metaheuristics
, Article 9th Annual Genetic and Evolutionary Computation Conference, GECCO 2007, London, 7 July 2007 through 11 July 2007 ; 2007 , Pages 909- ; 9781595936974 (ISBN) ; Hendizadeh, S. H ; Salmasi, N ; Sharif University of Technology
2007
Abstract
A bicriteria two-machine flowshop scheduling problem is addressed to minimize the number of setups and makespan. The jobs have sequence dependent setup times. Scheduling problems considering either of these objectives are NP-hard. Two multi-objective metaheurisctics based on genetic algorithms (MOGA) and simulated annealing (MOSA) are proposed to find approximations of Pareto-optimal frontiers. The performances of these approaches are compared with lower bounds for small problems. In larger problems, their performance is compared with each other. Experimentations revealed that both algorithms perform very similar on small problems and that MOGA outperforms MOSA in terms of the quality of...
A genetic algorithm for resource investment project scheduling problem, tardiness permitted with penalty
, Article European Journal of Operational Research ; Volume 181, Issue 1 , 2007 , Pages 86-101 ; 03772217 (ISSN) ; Kianfar, F ; Sharif University of Technology
2007
Abstract
In this paper a genetic algorithm for solving a class of project scheduling problems, called Resource Investment Problem, is presented. Tardiness of project is permitted with defined penalty. Elements of algorithm such as chromosome structure, unfitness function, crossover, mutation, immigration and local search operations are explained. The performance of this genetic algorithm is compared with the performance of other published algorithms for Resource Investment Problem. Also 690 problems are solved and their optimal solutions are used for the performance tests of the genetic algorithm. The tests results are quite satisfactory. © 2006 Elsevier B.V. All rights reserved
Solving the discrete time/resource trade-off problem in project scheduling with genetic algorithms
, Article Applied Mathematics and Computation ; Volume 191, Issue 2 , 2007 , Pages 451-456 ; 00963003 (ISSN) ; Kianfar, F ; Sharif University of Technology
2007
Abstract
In this paper, we develop a metaheuristic procedure for solving the discrete time/resource trade-off problem in the field of project scheduling. In this problem, a project contains activities interrelated by finish-start-type precedence constraints with a time lag of zero, which require a single constrained renewable resource. Each activity has a specified work content and can be performed in different modes, i.e. with different durations and resource requirements; as long as the required work content is met. The objective is to schedule each activity in one of its modes in order to minimize the project makespan. To tackle this problem, we use a genetic algorithm in which a new method based...
A new structure for electricity market scheduling
, Article 2006 International Conference on Power Electronics, Drives and Energy Systems, PEDES '06, New Delhi, 12 December 2006 through 15 December 2006 ; 2006 ; 078039772X (ISBN); 9780780397729 (ISBN) ; Ranjbar, A. M ; Shirani, A. R ; Sharif University of Technology
2006
Abstract
On pool market structure, the generating units are typically dispatched in order of lowest to highest bid as needed to meet demand requirement as well as considering network constraints. Generally, no account is taken of generating unit's reliability when scheduling them. This paper proposes a new structure for electricity market to consider generating unit's reliability in the scheduling problem. GAMS (General Algebraic Modeling System) language has been used to solve the social welfare maximization problem using CPLEX optimization software with mixed integer programming. ©2006 IEEE
Conventional and metaheuristic optimization algorithms for solving short term hydrothermal scheduling problem: a review
, Article IEEE Access ; Volume 9 , 2021 , Pages 25993-26025 ; 21693536 (ISSN) ; Liaquat, S ; Kashif, S. A. R ; Rasool, A ; Khizer, M ; Iqbal, M. A ; Baig, M. A ; Padmanaban, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Short term hydrothermal scheduling (STHTS) is a non-linear, multi-modal and very complex constrained optimization problem which has been solved using several conventional and modern metaheuristic optimization algorithms. A number of research articles have been published addressing STHTS using different techniques. This article presents a comprehensive review of research published for solving the STHTS problem in the last four decades. © 2013 IEEE
Flowshop-scheduling problems with makespan criterion: A review
, Article International Journal of Production Research ; Volume 43, Issue 14 , 2005 , Pages 2895-2929 ; 00207543 (ISSN) ; Saghafian, S ; Sharif University of Technology
2005
Abstract
This paper is a complete survey of flowshop-scheduling problems and contributions from early works of Johnson of 1954 to recent approaches of metaheuristics of 2004. It mainly considers a flowshop problem with a makespan criterion and it surveys some exact methods (for small size problems), constructive heuristics and developed improving metaheuristic and evolutionary approaches as well as some well-known properties and rules for this problem. Each part has a brief literature review of the contributions and a glimpse of that approach before discussing the implementation for a flowshop problem. Moreover, in the first section, a complete literature review of flowshop-related scheduling...
Energy-aware scheduling algorithm for precedence-constrained parallel tasks of network-intensive applications in a distributed homogeneous environment
, Article Proceedings of the 3rd International Conference on Computer and Knowledge Engineering, ICCKE 2013 ; 2013 , Pages 368-375 ; 9781479920921 (ISBN) ; Rajabi, A ; Goudarzi, M ; Sharif University of Technology
2013
Abstract
A wide range of scheduling algorithms used in the data centers have traditionally concentrated on enhancement of performance metrics. Recently, with the rapid growth of data centers in terms of both size and number, the power consumption has become a major challenge for both industry and society. At the software level, energy-aware task scheduling is an effective technique for power reduction in the data centers. However, most of the currently proposed energy-aware scheduling approaches are only paying attention to computation cost. In the other words, they ignore the energy consumed by the network equipment, namely communication cost. In this paper, the problem of scheduling...
Scheduling tasks with exponential duration on unrelated parallel machines
, Article Discrete Applied Mathematics ; Volume 160, Issue 16-17 , November , 2012 , Pages 2462-2473 ; 0166218X (ISSN) ; Ghodsi, M ; Sharif University of Technology
2012
Abstract
This paper introduces a stochastic scheduling problem. In this problem a directed acyclic graphs (DAG) represents the precedence relations among m tasks that n workers are scheduled to execute. The question is to find a schedule Σ such that if tasks are assigned to workers according to Σ, the expected time needed to execute all the tasks is minimized. The time needed to execute task t by worker w is a random variable expressed by a negative exponential distribution with parameter λ wt and each task can be executed by more than one worker at a time. In this paper, we will prove that the problem in its general form is NP-hard, but when the DAG width is constant, we will show that the optimum...
Lot streaming in a two-stage assembly hybrid flow shop scheduling problem with a work shift constraint
, Article Journal of Industrial and Production Engineering ; Volume 33, Issue 7 , 2016 , Pages 459-471 ; 21681015 (ISSN) ; Mahdavi, I ; Hassanzadeh, R ; Mahdavi Amiri, N ; Sharif University of Technology
Taylor and Francis Ltd
Abstract
We address the two-stage assembly scheduling problem where there are m machines at the first stage and n assembly machines at the second stage under lot sizing environment. Lot streaming (lot sizing) means breaking a lot into some sublots, where each sublot is transferred to the next machine for continuing operations. This problem can be considered as a production system model consisting of production stage and assembly stage. If different production operations are done in parallel machines independently, then the manufactured parts transferred to the next stage are assembled with purchased parts at n machines according to the operation process chart to produce the final products. Here,...
Bicriteria scheduling of a two-machine flowshop with sequence-dependent setup times
, Article International Journal of Advanced Manufacturing Technology ; Volume 40, Issue 11-12 , 2009 , Pages 1216-1226 ; 02683768 (ISSN) ; Hendizadeh, S. H ; Salmasi, N ; Sharif University of Technology
2009
Abstract
A two-machine flowshop scheduling problem is addressed to minimize setups and makespan where each job is characterized by a pair of attributes that entail setups on each machine. The setup times are sequence-dependent on both machines. It is shown that these objectives conflict, so the Pareto optimization approach is considered. The scheduling problems considering either of these objectives are N p - hard, so exact optimization techniques are impractical for large-sized problems. We propose two multi-objective metaheurisctics based on genetic algorithms (MOGA) and simulated annealing (MOSA) to find approximations of Pareto-optimal sets. The performances of these approaches are compared with...
A hybrid genetic and Lagrangian relaxation algorithm for resource-constrained project scheduling under nonrenewable resources
, Article Applied Soft Computing Journal ; Volume 94 , 2020 ; Shadrokh, S ; Khakifirooz, M ; Fathi, M ; Pardalos, P. M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Scheduling under nonrenewable resources is one of the challenging issues in project scheduling problems. There are many cases where the projects are subject to some nonrenewable resources. In most of the literature, nonrenewable resources are assumed to be available in full amount at the beginning of the project. However, in practice, it is prevalent that these resources are procured along the project horizon. This paper studies the generalized resource-constrained project scheduling problem (RCPSP) where, in addition to renewable resources, nonrenewable resources are considered, such as budget or consuming materials by the project activities. As the problem is NP-hard, some sub-algorithm...
A probabilistic task scheduling method for grid environments
, Article Future Generation Computer Systems ; Volume 28, Issue 3 , 2012 , Pages 513-524 ; 0167739X (ISSN) ; Movaghar, A ; Sharif University of Technology
Abstract
This paper presents a probabilistic task scheduling method to minimize the overall mean response time of the tasks submitted to the grid computing environments. Minimum mean response time of a given task can be obtained by finding a subset of appropriate computational resources to service the task. To achieve this, a discrete time Markov chain (DTMC) representing the task scheduling process within the grid environment is constructed. The connection probabilities between the nodes representing the grid managers and resources can be considered as transition probabilities of the obtained DTMC. Knowing the mean response times of the managers and resources, and finding fundamental matrix of the...
Lateral solutions for optimizing holding costs in job shops
, Article International Journal of Advanced Manufacturing Technology ; Volume 56, Issue 1-4 , 2011 , Pages 261-272 ; 02683768 (ISSN) ; Aliahmadi, A ; Sefidkoohi, H. M ; Omran, M. M ; Sharif University of Technology
Abstract
Queuing networks present as beneficial models for a category of problems emerging in modern manufacturing systems. As the optimal control problem for queuing networks in familiar to be difficult, an important topic of research during the last two decades has been the growth of difficult estimations, and the use of these estimations to control optimal controls. Flexible moderations are an important class of such estimations that have received much consideration in recent years. The central objective of this paper is to determine the utilization of flexible moderations in solving a diversity of scheduling problems. In this paper, we investigate the role of flexible moderations in solving...
A bee colony task scheduling algorithm in computational grids
, Article Communications in Computer and Information Science, 7 July 2011 through 9 July 2011 ; Volume 188 CCIS, Issue PART 1 , July , 2011 , Pages 200-210 ; 18650929 (ISSN) ; 9783642223884 (ISBN) ; Entezari Maleki, R ; Movaghar, A ; Springer ; Sharif University of Technology
2011
Abstract
The efficient scheduling of the independent and sequential tasks on distributed and heterogeneous computing resources within grid computing environments is an NP-complete problem. Therefore, using heuristic approaches to solve the scheduling problem is a very common and also acceptable method in these environments. In this paper, a new task scheduling algorithm based on bee colony optimization approach is proposed. The algorithm uses artificial bees to appropriately schedule the submitted tasks to the grid resources. Applying the proposed algorithm to the grid computing environments, the maximum delay and finish times of the tasks are reduced. Furthermore, the total makespan of the...
Single machine scheduling problem with batch outsourcing
, Article International Journal of Engineering, Transactions B: Applications ; Volume 35, Issue 5 , 2022 , Pages 1006-1016 ; 1728144X (ISSN) ; Kianfar, F ; Sharif University of Technology
Materials and Energy Research Center
2022
Abstract
Outsourcing as a useful strategy in the industry can be integrated into scheduling problems. Moreover, batch outsourcing is a practical assumption owing to the logistics issues for transferring the parts between the manufacturer and the subcontractors. However, this assumption is rarely addressed in the scheduling literature. In this paper, a novel single machine scheduling problem with the option of batch outsourcing is studied. The objective is to minimize the sum of the total completion time of the jobs and the total outsourcing cost. To solve the problem, first, two mixed-integer linear programming (MILP) models, named MP1 and MP2, are developed, which respectively use a straightforward...
Scheduling of Refinary Overhaul Activities Under Uncertainty, Case Study: Glycol Regeneration Unit of Farashband Refinary
, Ph.D. Dissertation Sharif University of Technology ; Shadrokh, Shahram (Supervisor)
Abstract
In order to maintain system reliability and high production rate, at oil, gas and petrochemical industries and other manufacturing plants, the plant is shut down and the planned maintenance activities are done on machines and equipment. In this research, a robust reliability-based scheduling for the maintenance activities are considered, in which the duration of maintenance activities and also project deadline are uncertain, start date and finish date of the shutdown are predefined and maintenance activities can be done in the multi-mode. The proposed problem is a multi-mode time-constrained project scheduling problem (MTCPSP). The glycol regeneration unit in a gas refinery is studied as the...
Timetable Synchronization Optimization for Urban Rail Transit Network
, M.Sc. Thesis Sharif University of Technology ; Shafahi, Yousef (Supervisor)
Abstract
Scheduling urban railway network is one of the most important parts of managing the rail transportation system. Therefore, researchers are trying to provide suitable solutions to produce an optimal timetable for the railway network. The purpose of this study is to provide a mathematical planning model to create a synchronized and optimal timetable for different lines of the railway network, including arrival time to each station and departure time from each station to reduce Travel time, waiting time at the origin station and transfer waiting time at the transfer station for passengers and maximize the number of passengers who successfully reach their destination in a specific study horizon....