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Due date assignment in single machine with stochastic processing times
, Article International Journal of Production Research ; Volume 51, Issue 8 , 2013 , Pages 2352-2362 ; 00207543 (ISSN) ; Salmasi, N ; Sharif University of Technology
2013
Abstract
This paper considers two different due date assignment and sequencing problems in single machine where the processing times of jobs are random variables. The first problem is to minimise the maximum due date so that all jobs are stochastically on time. It is shown that sequencing the jobs in decreasing service level (DSL) order optimally solves the problem. The results are then extended for two special cases of flow shop problem. The other problem is to minimise a total cost function which is a linear combination of three penalties: penalty on job earliness, penalty on job tardiness, and penalty associated with long due date assignment. The assignment of a common due date and distinct due...
Heuristic rules for tardiness problem in flow shop with intermediate due dates
, Article International Journal of Advanced Manufacturing Technology ; Vol. 71, issue. 1-4 , 2014 , pp. 381-393 ; ISSN: 02683768 ; Olfat, L ; Sharif University of Technology
Abstract
In this paper, the tardiness flow shop models with intermediate due date were considered. The flow shop models consist of a set of jobs each having a number of operations, while each operation is performed in a single machine. All the jobs are considered having the same unidirectional precedence order. In the tardiness flow shop models with intermediate due date, which we call the generalized tardiness flow shop models, there exist a due date associated with the completion of each operation, and we want to find a schedule which minimizes the total tardiness of the jobs. This is a more general version of tardiness flow shop in the sense that, by assigning a large value to each of the...
Preemptive multi-skilled resource constrained project scheduling problem with hard/soft interval due dates
, Article RAIRO - Operations Research ; Volume 53, Issue 5 , 2019 , Pages 1877-1898 ; 03990559 (ISSN) ; Afshar Nadjafi, B ; Akhavan Niaki, S. T ; Sharif University of Technology
EDP Sciences
2019
Abstract
This paper considers a preemptive multi-skilled resource constrained project scheduling problem in a just-in-time environment where each activity has an interval due date to be completed. In this problem setting, resuming a preempted activity requires an extra setup cost, while each time unit violation from the given due date incurs earliness or tardiness penalty. Also, processing cost of each skill to execute any activity depends on the assigned staff member to accomplish the skill. The objective function of the model aims to minimize the total cost of allocating staff to skills, earliness-tardiness penalties and preemption costs. Two integer formulations are proposed for the model which...
Lead Time Quotation and Lot Sizing in Production Systems
, Ph.D. Dissertation Sharif University of Technology ; Kianfar, Farhad (Supervisor)
Abstract
Due date assignment for customer orders has been studied in various production environments. In this thesis a production system is considered in which the orders of several customers are produced in a single lot because of the economy of scale. If a lot is completed before receiving customer orders, inventory carrying cost is incurred. On shortages, a due date is quoted to customers and lead time quotation cost is incurred. The due date may not be met because of (lead-time) uncertainty in production system. Hence if the order is delivered after its due date, tardiness cost is charged. The literature reviews show that such a model is not considered by other researchers. Two different problems...
Order Production Planning, and Meeting Due-Dates for MTO Reconfigurable Manufacturing Systems
, M.Sc. Thesis Sharif University of Technology ; Houshmand, Mahmoud (Supervisor)
Abstract
Time based competition is considered as an importance strategy in the contemporary manufacturing systems. Reconfigurable Manufacturing System (RMS) is a new paradigm that not only produces the products with high productivity but also allows for rapid response to market changes. Despite the large impact on company performance, the importance of due date setting and order planning processes and related decisions is underexposed in the literature of RMS. The most important contribution of this thesis is orders planning under setting due date in make-to-order RMS environment. This thesis seeks to determine the best selection of several orders, their sequencing and corresponding configurations...
Ant colony optimisation for the bi-objective due-date-setting problem in the multi-class make-to-order firm
, Article International Journal of Industrial and Systems Engineering ; Volume 13, Issue 4 , 2013 , Pages 496-520 ; 17485037 (ISSN) ; Chaharsooghi, S. K ; Modarres, M ; Sharif University of Technology
2013
Abstract
In this study, we develop a bi-objective programming approach for due-date setting in make-to-order manufacturing with different classes of customers. We formulate the problem of quoting due-dates under the assumption that demand is dependent on lead-time and price is determined by the length of the delivery time. In addition, other parameters such as production policy, inventory holding, delivery system and capacity utilisation should be considered in due-date decisions. To this purpose, we consider additional objective function in traditional due-date management problem. So, the proposed bi-objective model attempts to maximise total profit and minimise rates of changes in capacity...
Due date assignment in repetitive projects
, Article International Journal of Production Economics ; Volume 129, Issue 1 , January , 2011 , Pages 79-85 ; 09255273 (ISSN) ; Fynes, B ; Modarres, M ; Sharif University of Technology
2011
Abstract
This paper is concerned with the study of the constant due-date assignment policy in repetitive projects, where the activity durations are exponentially distributed random variables. It is then extended to the case where activity durations follow generalized Erlang distributions. The main feature of this research over the classical PERT networks is that the projects are generated according to a renewal process and share the same facilities. Our approach is first to obtain the project completion time distribution, for each generated project, by constructing a proper continuous-time Markov chain, and then to compute the optimal constant lead time for each particular project. The repetitive...
Generalized Tardiness Flow Shop Problem
, M.Sc. Thesis Sharif University of Technology ; Shavandi, Hassan (Supervisor)
Abstract
In this thesis, several metaheusristic algorithms for solving the generalized tardiness flow shop problem are proposed. In the generalized tardiness flowshop a due date is defined for every operation of the jobs. With the best of our knowledge is the first attempt to develop a genetic algorithm for the proposed problem. Several genetic algorithms are develpoed based on selecting the parents.The proposed GAs are tunned using experimtal analysis and the efficiency of lgorithms are analyzed with many randomly generated problems. Sensitivity analysis is also done to drive mangerial insights
Optimal constrained non-renewable resource allocation in PERT networks with discrete activity times
, Article Scientia Iranica ; Volume 19, Issue 3 , 2012 , Pages 841-848 ; 10263098 (ISSN) ; Fatemi Ghomi, S. M. T ; Modarres, M ; Sharif University of Technology
2012
Abstract
In this paper, we develop an approach to optimally allocate a limited nonrenewable resource among the activities of a project, represented by a PERT-Type Network (PTN). The project needs to be completed within some specified due date. The objective is to maximize the probability of project completion on time. The duration of each activity is an arbitrary discrete random variable and also depends on the amount of consumable resource allocated to it. On the basis of the structure of networks, they are categorized as either reducible or irreducible. For each network structure, an analytical algorithm is presented. Through some examples, the algorithms are illustrated
Due date assignment for multistage assembly systems
, Article Optimization Letters ; Volume 3, Issue 2 , 2009 , Pages 199-210 ; 18624472 (ISSN) ; Kianfar, F ; Sharif University of Technology
2009
Abstract
This paper is concerned with the study of the constant due-date assignment policy in a multistage assembly system. The multistage assembly system is modeled as an open queueing network. It is assumed that the product order arrives according to a Poisson process. In each service station, there is either one or infinite machine with exponentially distributed processing time. The transport times between every pair of service stations are independent random variables with generalized Erlang distributions. It is assumed that each product has a penalty cost that is some linear function of its due-date and its actual completion time. The due date is found by adding a constant to the time that the...
Simultaneous Due date assignment and lot sizing with uncertain flow times
, Article International Journal of Engineering, Transactions A: Basics ; Volume 20, Issue 3 , 2007 , Pages 263-280 ; 17281431 (ISSN) ; Kianfar, F ; Sharif University of Technology
Materials and Energy Research Center
2007
Abstract
Due date assignment for customer orders has been studied in various production environments using different modeling approaches. In this paper the researchers consider a production system in which the orders of several customers are produced in a single batch because of the economy of scale. If a batch is completed before receiving customer orders, inventory carrying cost is incurred but if it is completed after receiving customer orders, shortage cost is incurred and finally if the order is delivered after its due date, tardiness cost is charged. The problem is to decide on batch size, due date of batch (imposed on supply process) and lead time (to be quoted to the next coming customers) so...
Stochastic Scheduling in Single Machine and Flow Shop Environments
, Ph.D. Dissertation Sharif University of Technology ; Salmasi, Naser (Supervisor)
Abstract
Sequencing and scheduling of jobs are decision making processes that are used in many manufacturing and service industries. In the traditional scheduling models, it is assumed that the values for all the problem parameters are constant and known in advance. However, production environments in the real world are subject to many sources of uncertainty or randomness. This research investigates three different types of stochastic scheduling problems. In the first case, the problem is minimizing the number of tardy jobs in the class of static list policies, where the job processing times are random variables. For this case, the stochastic problems in single machine and flow shop environments are...
A modified PSO algorithm for minimizing the total costs of resources in MRCPSP
, Article Mathematical Problems in Engineering ; Volume 2012 , 2012 ; 1024123X (ISSN) ; Kianfar, F ; Shirzadeh Chaleshtari, A ; Shadrokh, S ; Ranjbar, M ; Sharif University of Technology
2012
Abstract
We introduce a multimode resource-constrained project scheduling problem with finish-to-start precedence relations among project activities, considering renewable and nonrenewable resource costs. We assume that renewable resources are rented and are not available in all periods of time of the project. In other words, there is a mandated ready date as well as a due date for each renewable resource type so that no resource is used before its ready date. However, the resources are permitted to be used after their due dates by paying penalty costs. The objective is to minimize the total costs of both renewable and nonrenewable resource usage. This problem is called multimode resource-constrained...
An optimal procedure for minimizing total weighted resource tardiness penalty costs in the resource-constrained project scheduling problem
, Article Computers and Industrial Engineering ; Volume 62, Issue 1 , 2012 , Pages 264-270 ; 03608352 (ISSN) ; Khalilzadeh, M ; Kianfar, F ; Etminani, K ; Sharif University of Technology
Abstract
We present an optimal solution procedure for minimizing total weighted resource tardiness penalty costs in the resource-constrained project scheduling problem. In this problem, we assume the constrained renewable resources are limited to very expensive equipments and machines that are used in other projects and are not available in all periods of time of a project. In other words, for each resource, there is a dictated ready date as well as a due date such that no resource can be available before its ready date but the resources are permitted to be used after their due dates by paying penalty cost depending on the resource type. We also assume that only one unit of each resource type is...
Lot sizing and lead time quotations in assembly systems
, Article Scientia Iranica ; Volume 16, Issue 2 E , 2009 , Pages 100-113 ; 10263098 (ISSN) ; Mokhtari, G ; Sharif University of Technology
Abstract
In this paper, a simultaneous lead time quotation and lot sizing problem in an assembly system is investigated. We address a production system with a product that has deterministic demand over a T-period planning horizon and is produced in lots because of the economy of scale. If a lot is completed before the demand period, inventory carrying cost is incurred. On shortages, a lead time is quoted to customers and a lead time quotation cost is incurred. Finally, if the order is delivered later than its due date period, a tardiness cost is charged. The components supply lead time is stochastic, which follows a discrete distribution. The problem is to decide on the lot size of products and...
A multi-stage stochastic programming model for dynamic pricing and lead time decisions in multi-class make-to-order firm
, Article Scientia Iranica ; Volume 18, Issue 3 E , 2011 , Pages 711-721 ; 10263098 (ISSN) ; Honarvar, M ; Modarres, M ; Sharif University of Technology
2011
Abstract
Make-to-order firms use different strategies, such as dynamic pricing and due date management, to influence their performance. In these strategies, orders are segmented into classes based on their sensitivity to lead time and price. Quoting different prices and lead times to different classes of customer can increase a firm's profit and its capacity utilization. Most research in this area does not consider the effects of production constraints on price and lead time decisions. In this paper, we consider the role of flexibility in dynamically choosing the price, lead time and segmentation of customers in make-to-order environments with limited production capacity and multi-period horizon...