International Journal of Industrial Engineering Computations, 2016
Scheduling and layout planning are two important areas of operations research, which are used in ... more Scheduling and layout planning are two important areas of operations research, which are used in the areas of production planning, logistics and supply chain management. In many industries locations of machines are not specified, previously, therefore, it is necessary to consider both location and scheduling, simultaneously. This paper presents a mathematical model to consider both scheduling and layout planning for parallel machines in discrete and continuous spaces, concurrently. The preliminary results have indicated that the integrated model is capable of handling problems more efficiently.
Reliability optimization plays an important role in design, operation and management of the indus... more Reliability optimization plays an important role in design, operation and management of the industrial systems. System reliability can be easily enhanced by improving the reliability of unreliable components and/or by using redundant configuration with subsystems/components in parallel. Redundancy Allocation Problem (RAP) was studied in this research. A mixed integer programming model was proposed to solve the problem, which considers simultaneously two objectives under several resource constraints. The model is only for the hierarchical series-parallel systems in which the elements of any subset of subsystems or components are connected in series or parallel and constitute a larger subsystem or total system. At the end of the study, the performance of the proposed approach was evaluated by a numerical example.
International Journal of Industrial Engineering Computations, 2010
Vendor Managed Inventory (VMI) is one of the effective techniques for managing the inventory in s... more Vendor Managed Inventory (VMI) is one of the effective techniques for managing the inventory in supply chain. VMI models have been proven to reduce the cost of inventory compared with traditional economic order quantity method under some conditions such as constant demand and production expenditure. However, the modeling of the VMI problem has never been studied under some realistic assumptions such as price dependent demand. In this paper, three problem formulations are proposed. In the first problem formulation, we study a VMI problem with one buyer and one supplier when demand is considered to be a function of price and price elasticity to demand, and production cost is also a function of demand. The proposed model is formulated and solved in a form of geometric programming. For the second and the third models, we consider VMI problem with two buyers and two suppliers assuming that each buyer centre is relatively close to the other buyer centre. Each supplier has only one product which is different from the product of the other supplier. Two suppliers cooperate in customer relationship management and two buyers cooperate in supplier relationship management as well, so the suppliers send the orders of two buyers by one vehicle, simultaneously. For the third model, an additional assumption which is practically applicable and reasonable is considered. For all the proposed models, the optimal solution is compared with the traditional one. We demonstrate the implementation of our proposed models using some numerical examples.
A Price Discrimination Modeling Using Geometric Programming
Lecture Notes in Computer Science, 2006
This paper presents a price discrimination model which determines the product’s selling price and... more This paper presents a price discrimination model which determines the product’s selling price and marketing expenditure in two markets. We assume production as a function of price and marketing cost in two states. The cost of production is also assumed to be a function of production in both markets. We propose a Multi Objective Decision Making (MODM) method called Lexicograph Approach (LA) in order to find an efficient solution between two objectives for each market. Geometric Programming is used to solve the resulted model. In our GP implementation, we use a transformed dual problem in order to reduce the model to an optimization of a nonlinear concave function subject to some linear constraints and solved the resulted model using a simple grid line search.
The International Journal of Advanced Manufacturing Technology, 2014
This paper deals with the flexible job shop scheduling problem with the objective of minimizing t... more This paper deals with the flexible job shop scheduling problem with the objective of minimizing the makespan. An efficient heuristic based on a constructive procedure is developed to obtain high-quality schedules very quickly. The algorithm is tested on benchmark instances from the literature in order to evaluate its performance. Computational results show that, despite its simplicity, the proposed heuristic can obtain effective solutions in very short and nearly zero time and is comparable with even metaheuristic algorithms and promising for practical problems.
A modular approach to ERP system selection: A case study
Information Management & Computer Security, 2006
Design/methodology/approach In the first phase of the proposed method the preliminary actions ... more Design/methodology/approach In the first phase of the proposed method the preliminary actions such as constructing a project team, collecting all possible information about ERP vendors and systems, and identifying the ERP system characteristics are established. In the ...
The distributed manufacturing takes place in a multi-factory environment including several factor... more The distributed manufacturing takes place in a multi-factory environment including several factories, which may be geographically distributed in different locations, or in a multi-cell environment including several independent manufacturing cells located in the same plant. Each factory/cell is capable of manufacturing a variety of product types. An important issue in dealing with the production in this decentralized manner is the scheduling of manufacturing operations of products (jobs) in the distributed manufacturing system. In this paper, we study the distributed and flexible job-shop scheduling problem (DFJSP) which involves the scheduling of jobs (products) in a distributed manufacturing environment, under the assumption that the shop floor of each factory/cell is configured as a flexible job shop. A fast heuristic algorithm based on a constructive procedure is developed to obtain good quality schedules very quickly. The algorithm is tested on benchmark instances from the literature in order to evaluate its performance. Computational results show that, despite its simplicity, the proposed heuristic is computationally efficient and promising for practical problems.
International Journal of Industrial Engineering Computations, 2016
Scheduling and layout planning are two important areas of operations research, which are used in ... more Scheduling and layout planning are two important areas of operations research, which are used in the areas of production planning, logistics and supply chain management. In many industries locations of machines are not specified, previously, therefore, it is necessary to consider both location and scheduling, simultaneously. This paper presents a mathematical model to consider both scheduling and layout planning for parallel machines in discrete and continuous spaces, concurrently. The preliminary results have indicated that the integrated model is capable of handling problems more efficiently.
Reliability optimization plays an important role in design, operation and management of the indus... more Reliability optimization plays an important role in design, operation and management of the industrial systems. System reliability can be easily enhanced by improving the reliability of unreliable components and/or by using redundant configuration with subsystems/components in parallel. Redundancy Allocation Problem (RAP) was studied in this research. A mixed integer programming model was proposed to solve the problem, which considers simultaneously two objectives under several resource constraints. The model is only for the hierarchical series-parallel systems in which the elements of any subset of subsystems or components are connected in series or parallel and constitute a larger subsystem or total system. At the end of the study, the performance of the proposed approach was evaluated by a numerical example.
International Journal of Industrial Engineering Computations, 2010
Vendor Managed Inventory (VMI) is one of the effective techniques for managing the inventory in s... more Vendor Managed Inventory (VMI) is one of the effective techniques for managing the inventory in supply chain. VMI models have been proven to reduce the cost of inventory compared with traditional economic order quantity method under some conditions such as constant demand and production expenditure. However, the modeling of the VMI problem has never been studied under some realistic assumptions such as price dependent demand. In this paper, three problem formulations are proposed. In the first problem formulation, we study a VMI problem with one buyer and one supplier when demand is considered to be a function of price and price elasticity to demand, and production cost is also a function of demand. The proposed model is formulated and solved in a form of geometric programming. For the second and the third models, we consider VMI problem with two buyers and two suppliers assuming that each buyer centre is relatively close to the other buyer centre. Each supplier has only one product which is different from the product of the other supplier. Two suppliers cooperate in customer relationship management and two buyers cooperate in supplier relationship management as well, so the suppliers send the orders of two buyers by one vehicle, simultaneously. For the third model, an additional assumption which is practically applicable and reasonable is considered. For all the proposed models, the optimal solution is compared with the traditional one. We demonstrate the implementation of our proposed models using some numerical examples.
A Price Discrimination Modeling Using Geometric Programming
Lecture Notes in Computer Science, 2006
This paper presents a price discrimination model which determines the product’s selling price and... more This paper presents a price discrimination model which determines the product’s selling price and marketing expenditure in two markets. We assume production as a function of price and marketing cost in two states. The cost of production is also assumed to be a function of production in both markets. We propose a Multi Objective Decision Making (MODM) method called Lexicograph Approach (LA) in order to find an efficient solution between two objectives for each market. Geometric Programming is used to solve the resulted model. In our GP implementation, we use a transformed dual problem in order to reduce the model to an optimization of a nonlinear concave function subject to some linear constraints and solved the resulted model using a simple grid line search.
The International Journal of Advanced Manufacturing Technology, 2014
This paper deals with the flexible job shop scheduling problem with the objective of minimizing t... more This paper deals with the flexible job shop scheduling problem with the objective of minimizing the makespan. An efficient heuristic based on a constructive procedure is developed to obtain high-quality schedules very quickly. The algorithm is tested on benchmark instances from the literature in order to evaluate its performance. Computational results show that, despite its simplicity, the proposed heuristic can obtain effective solutions in very short and nearly zero time and is comparable with even metaheuristic algorithms and promising for practical problems.
A modular approach to ERP system selection: A case study
Information Management & Computer Security, 2006
Design/methodology/approach In the first phase of the proposed method the preliminary actions ... more Design/methodology/approach In the first phase of the proposed method the preliminary actions such as constructing a project team, collecting all possible information about ERP vendors and systems, and identifying the ERP system characteristics are established. In the ...
The distributed manufacturing takes place in a multi-factory environment including several factor... more The distributed manufacturing takes place in a multi-factory environment including several factories, which may be geographically distributed in different locations, or in a multi-cell environment including several independent manufacturing cells located in the same plant. Each factory/cell is capable of manufacturing a variety of product types. An important issue in dealing with the production in this decentralized manner is the scheduling of manufacturing operations of products (jobs) in the distributed manufacturing system. In this paper, we study the distributed and flexible job-shop scheduling problem (DFJSP) which involves the scheduling of jobs (products) in a distributed manufacturing environment, under the assumption that the shop floor of each factory/cell is configured as a flexible job shop. A fast heuristic algorithm based on a constructive procedure is developed to obtain good quality schedules very quickly. The algorithm is tested on benchmark instances from the literature in order to evaluate its performance. Computational results show that, despite its simplicity, the proposed heuristic is computationally efficient and promising for practical problems.
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Papers by Mohsen Ziaee