Hani Pourvaziri - Academia.edu (original) (raw)

Papers by Hani Pourvaziri

Research paper thumbnail of Dealing with Capacitated Aisles in Facility Layout: A Simulation Optimization Approach

Dealing with Capacitated Aisles in Facility Layout: A Simulation Optimization Approach

Advances in Intelligent Systems and Computing, 2018

In manufacturing systems layout of machines has a significant impact on production time and cost.... more In manufacturing systems layout of machines has a significant impact on production time and cost. The most important reason for this is that machine layout impact on transportation time and cost. When designing layout, the aisles structure has an effect on transportation. The aisles are paths that transporters go through them to move the materials between machines. The capacity of the aisles is not infinitive and there is a limitation for the number of transporters that can pass an aisle at the same time. This causes transporters wait for the aisle to be empty or even transporters crossing. Therefore, when optimizing the layout of machines, the aisles structure and their capacity must be investigated. This paper proposes an approach for layout design in manufacturing systems taking into account capacitated aisles structure. First, the aisle structure is determined. Then, the machines are assigned in the possible areas. A simulation optimization approach is proposed to solve the problem. This helps us to avoid unrealistic assumptions and consider realistic conditions such as stochastic characteristics of the manufacturing system, random process time and random breakdown. A genetic algorithm is used to search for the best position of machines. Finally, a numerical example is included to illustrate the proposed approach.

Research paper thumbnail of Combining metaheuristic search and simulation to deal with capacitated aisles in facility layout

Neurocomputing, 2020

background: Many NSTEACS patients are medically managed without coronary revascularization. The r... more background: Many NSTEACS patients are medically managed without coronary revascularization. The reasons vary and may impact prognosis. methods: EPICOR Asia (NCT01361386) is a prospective study of hospital survivors post ACS enrolled in 219 hospitals from 8 countries/ regions in Asia (06/2011-05/2012). All medically managed NSTEACS patients in EPICOR Asia were classified into 3 groups: 1) no coronary angiography (CAG-); 2) non-significant coronary artery disease (CAD) on angiogram (CAG+ CAD-); and 3) significant CAD (CAG+ CAD+). We compared baseline differences between groups, and report 1-y mortality rates. Results: Of 6,164 NSTEACS patients, 2,272 (37%) were medically managed only, with 1,339 (59%), 254 (11%) and 679 (30%) patients in the CAG-, CAG+ CAD-, and CAG+ CAD+ groups, respectively. There were marked differences in number of NSTEACS patients medically managed among the 8 countries/regions (13-81%). Between-group differences were seen in baseline characteristics (Table). CAG+ CADpatients were younger with fewer CV risk factors than CAG+ CAD+. CAG-patients were older, more likely with known CV disease, more frequently admitted to hospitals with no cath lab, and had the highest 1-y mortality (6.9% versus 3.3% for EPICOR Asia overall). conclusion: NSTEACS patients who are medically managed are a heterogeneous group with different clinical features and outcomes e.g. mortality risk. The factors underlying different management strategies, and to improve prognosis, need to be identified.

Research paper thumbnail of Integrating facility layout design and aisle structure in manufacturing systems: Formulation and exact solution

European Journal of Operational Research, 2020

In manufacturing systems, aisles are paths which are used for the movement of workers, transporta... more In manufacturing systems, aisles are paths which are used for the movement of workers, transportation devices, and materials. The aisle structure contributes to layout efficiency by reducing material handling costs, mean flow time and the amount of space needed, and providing smooth transportation. Therefore, to achieve a good layout, it is essential to determine the position of facilities such as machines and workstations, but also the corresponding aisle structure. In this article, we analyze the requirements for the design of an efficient aisle structure and propose a formulation of the corresponding layout problem as a mixed-integer linear programming model. This formulation allows the layout of unequal-area facilities and the aisle structure to be simultaneously optimized. In optimizing the aisle structure, issues such as optimizing the number, position, and width of the aisles, the position of the entrance and exit doors, and how to connect them to the aisles are studied. By optimizing the number and width of the aisles, the proposed approach contributes towards optimizing transportation traffic. A branch-and-cut algorithm, improved by adding optimality cuts and efficient branching and node strategies, is used to solve the problem. Finally, a set of computational experiments is performed to show the effectiveness of the proposed approach.

Research paper thumbnail of Dynamic facility layout problem based on open queuing network theory

European Journal of Operational Research, 2017

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  The layout objectives concern handling and restarting costs and work-in-process.  Cloud based multi-objective simulated annealing is used.  An open queuing network is used to allow material handling and work-in-process to be estimated.  Results are verified through the use of simulation experiments.  Extensive experiments show the efficiency of the approach.

Research paper thumbnail of A r c h i v e o f S I D A New Hybrid Parallel Simulated Annealing Algorithm for Travelling Salesman Problem with Multiple Transporters

In today's competitive transportation systems, passengers search to find traveling agencies ... more In today's competitive transportation systems, passengers search to find traveling agencies that are able to serve them efficiently considering both traveling time and transportation costs. In this paper, we present a new model for the traveling salesman problem with multiple transporters (TSPMT). In the proposed model, which is more applicable than the traditional versions, each city has different transporting vehicles and the cost of travel through each city is dependent on the transporting vehicles type. The aim is to determine an optimal sequence of visited cities with minimum traveling times by available transporting vehicles within a limited budget. First, the mathematical model of TSPMT is presented. Next, since the problem is NP-hard, a new hybrid parallel simulated annealing algorithm with a new coding scheme is proposed. To analyze the performance of the proposed algorithm, 50 numerical examples with different budget types are examined and solved using the algorithm. ...

Research paper thumbnail of A Tunned-parameter Hybrid Algorithm for Dynamic Facility Layout Problem with Budget Constraint using GA and SAA

Journal of Optimization in Industrial Engineering, 2014

A facility layout problem is concerned with determining the best position of departments, cells, ... more A facility layout problem is concerned with determining the best position of departments, cells, or machines on the plant. An efficient layout contributes to the overall efficiency of operations. It’s been proved that, when system characteristics change, it can cause a significant increase in material handling cost. Consequently, the efficiency of the current layout decreases or is lost and it does necessitate rearrangement. On the other hand, the rearrangement of the workstations may burden a lot of expenses on the system. The problem that considers balance between material handling cost and the rearrangement cost is known as the Dynamic Facility Layout Problem (DFLP). The objective of a DFLP is to find the best layout for the company facilities in each period of planning horizon considering the rearrangement costs. Due to the complex structure of the problem, there are few researches in the literature which tried to find near optimum solutions for DFLP with budget constraint. In t...

Research paper thumbnail of Multi-echelon supply chain network modelling and optimization via simulation and metaheuristic algorithms

Scientia Iranica, 2016

An important problem in todays industries is the cost issue, due to the high level of competition... more An important problem in todays industries is the cost issue, due to the high level of competition in the global market. This fact obliges organizations to focus on improvement of their production-distribution routes, in order to nd the best. The Supply Chain Network (SCN) is one of the, so-called, production-distribution models that has many layers and/or echelons. In this paper, a new SCN, which is more compatible with real world problems is presented, and then, two novel hybrid algorithms have been developed to solve the model. Each hybrid algorithm integrates the simulation technique with two metaheuristic algorithms, including the Genetic Algorithm (GA) and the Simulated Annealing Algorithm (SAA), namely, HSIM-META. The output of the simulation model is inserted as the initial population in tuned-parameter metaheuristic algorithms to nd near optimum solutions, which is in fact a new approach in the literature. To analyze the performance of the proposed algorithms, di erent numerical examples are presented. The computational results of the proposed HSIM-META, including hybrid simulation-GA (HSIM-GA) and hybrid simulation-SAA (HSIM-SAA), are compared to the GA and the SAA. Computational results show that the proposed HSIM-META has suitable accuracy and speed for use in real world applications.

Research paper thumbnail of A New Hybrid Parallel Simulated Annealing Algorithm for Travelling Salesman Problem with Multiple Transporters

Journal of Optimization in Industrial Engineering, 2014

In today’s competitive transportation systems, passengers search to find traveling agencies that ... more In today’s competitive transportation systems, passengers search to find traveling agencies that are able to serve them efficiently considering both traveling time and transportation costs. In this paper, we present a new model for the traveling salesman problem with multiple transporters (TSPMT). In the proposed model, which is more applicable than the traditional versions, each city has different transporting vehicles and the cost of travel through each city is dependent on the transporting vehicles type. The aim is to determine an optimal sequence of visited cities with minimum traveling times by available transporting vehicles within a limited budget. First, the mathematical model of TSPMT is presented. Next, since the problem is NP-hard, a new hybrid parallel simulated annealing algorithm with a new coding scheme is proposed. To analyze the performance of the proposed algorithm, 50 numerical examples with different budget types are examined and solved using the algorithm. The c...

Research paper thumbnail of Multi-echelon supply chain network modelling and optimization via simulation and metaheuristic algorithms

An important problem in todays industries is the cost issue, due to the high level of competition... more An important problem in todays industries is the cost issue, due to the high level of competition in the global market. This fact obliges organizations to focus on improvement of their production-distribution routes, in order to nd the best. The Supply Chain Network (SCN) is one of the, so-called, production-distribution models that has many layers and/or echelons. In this paper, a new SCN, which is more compatible with real world problems is presented, and then, two novel hybrid algorithms have been developed to solve the model. Each hybrid algorithm integrates the simulation technique with two metaheuristic algorithms, including the Genetic Algorithm (GA) and the Simulated Annealing Algorithm (SAA), namely, HSIM-META. The output of the simulation model is inserted as the initial population in tuned-parameter metaheuristic algorithms to nd near optimum solutions, which is in fact a new approach in the literature. To analyze the performance of the proposed algorithms, diierent numerical examples are presented. The computational results of the proposed HSIM-META, including hybrid simulation-GA (HSIM-GA) and hybrid simulation-SAA (HSIM-SAA), are compared to the GA and the SAA. Computational results show that the proposed HSIM-META has suitable accuracy and speed for use in real world applications.

Research paper thumbnail of Dealing with Capacitated Aisles in Facility Layout: A Simulation Optimization Approach

Dealing with Capacitated Aisles in Facility Layout: A Simulation Optimization Approach

Advances in Intelligent Systems and Computing, 2018

In manufacturing systems layout of machines has a significant impact on production time and cost.... more In manufacturing systems layout of machines has a significant impact on production time and cost. The most important reason for this is that machine layout impact on transportation time and cost. When designing layout, the aisles structure has an effect on transportation. The aisles are paths that transporters go through them to move the materials between machines. The capacity of the aisles is not infinitive and there is a limitation for the number of transporters that can pass an aisle at the same time. This causes transporters wait for the aisle to be empty or even transporters crossing. Therefore, when optimizing the layout of machines, the aisles structure and their capacity must be investigated. This paper proposes an approach for layout design in manufacturing systems taking into account capacitated aisles structure. First, the aisle structure is determined. Then, the machines are assigned in the possible areas. A simulation optimization approach is proposed to solve the problem. This helps us to avoid unrealistic assumptions and consider realistic conditions such as stochastic characteristics of the manufacturing system, random process time and random breakdown. A genetic algorithm is used to search for the best position of machines. Finally, a numerical example is included to illustrate the proposed approach.

Research paper thumbnail of Combining metaheuristic search and simulation to deal with capacitated aisles in facility layout

Neurocomputing, 2020

background: Many NSTEACS patients are medically managed without coronary revascularization. The r... more background: Many NSTEACS patients are medically managed without coronary revascularization. The reasons vary and may impact prognosis. methods: EPICOR Asia (NCT01361386) is a prospective study of hospital survivors post ACS enrolled in 219 hospitals from 8 countries/ regions in Asia (06/2011-05/2012). All medically managed NSTEACS patients in EPICOR Asia were classified into 3 groups: 1) no coronary angiography (CAG-); 2) non-significant coronary artery disease (CAD) on angiogram (CAG+ CAD-); and 3) significant CAD (CAG+ CAD+). We compared baseline differences between groups, and report 1-y mortality rates. Results: Of 6,164 NSTEACS patients, 2,272 (37%) were medically managed only, with 1,339 (59%), 254 (11%) and 679 (30%) patients in the CAG-, CAG+ CAD-, and CAG+ CAD+ groups, respectively. There were marked differences in number of NSTEACS patients medically managed among the 8 countries/regions (13-81%). Between-group differences were seen in baseline characteristics (Table). CAG+ CADpatients were younger with fewer CV risk factors than CAG+ CAD+. CAG-patients were older, more likely with known CV disease, more frequently admitted to hospitals with no cath lab, and had the highest 1-y mortality (6.9% versus 3.3% for EPICOR Asia overall). conclusion: NSTEACS patients who are medically managed are a heterogeneous group with different clinical features and outcomes e.g. mortality risk. The factors underlying different management strategies, and to improve prognosis, need to be identified.

Research paper thumbnail of Integrating facility layout design and aisle structure in manufacturing systems: Formulation and exact solution

European Journal of Operational Research, 2020

In manufacturing systems, aisles are paths which are used for the movement of workers, transporta... more In manufacturing systems, aisles are paths which are used for the movement of workers, transportation devices, and materials. The aisle structure contributes to layout efficiency by reducing material handling costs, mean flow time and the amount of space needed, and providing smooth transportation. Therefore, to achieve a good layout, it is essential to determine the position of facilities such as machines and workstations, but also the corresponding aisle structure. In this article, we analyze the requirements for the design of an efficient aisle structure and propose a formulation of the corresponding layout problem as a mixed-integer linear programming model. This formulation allows the layout of unequal-area facilities and the aisle structure to be simultaneously optimized. In optimizing the aisle structure, issues such as optimizing the number, position, and width of the aisles, the position of the entrance and exit doors, and how to connect them to the aisles are studied. By optimizing the number and width of the aisles, the proposed approach contributes towards optimizing transportation traffic. A branch-and-cut algorithm, improved by adding optimality cuts and efficient branching and node strategies, is used to solve the problem. Finally, a set of computational experiments is performed to show the effectiveness of the proposed approach.

Research paper thumbnail of Dynamic facility layout problem based on open queuing network theory

European Journal of Operational Research, 2017

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  The layout objectives concern handling and restarting costs and work-in-process.  Cloud based multi-objective simulated annealing is used.  An open queuing network is used to allow material handling and work-in-process to be estimated.  Results are verified through the use of simulation experiments.  Extensive experiments show the efficiency of the approach.

Research paper thumbnail of A r c h i v e o f S I D A New Hybrid Parallel Simulated Annealing Algorithm for Travelling Salesman Problem with Multiple Transporters

In today's competitive transportation systems, passengers search to find traveling agencies ... more In today's competitive transportation systems, passengers search to find traveling agencies that are able to serve them efficiently considering both traveling time and transportation costs. In this paper, we present a new model for the traveling salesman problem with multiple transporters (TSPMT). In the proposed model, which is more applicable than the traditional versions, each city has different transporting vehicles and the cost of travel through each city is dependent on the transporting vehicles type. The aim is to determine an optimal sequence of visited cities with minimum traveling times by available transporting vehicles within a limited budget. First, the mathematical model of TSPMT is presented. Next, since the problem is NP-hard, a new hybrid parallel simulated annealing algorithm with a new coding scheme is proposed. To analyze the performance of the proposed algorithm, 50 numerical examples with different budget types are examined and solved using the algorithm. ...

Research paper thumbnail of A Tunned-parameter Hybrid Algorithm for Dynamic Facility Layout Problem with Budget Constraint using GA and SAA

Journal of Optimization in Industrial Engineering, 2014

A facility layout problem is concerned with determining the best position of departments, cells, ... more A facility layout problem is concerned with determining the best position of departments, cells, or machines on the plant. An efficient layout contributes to the overall efficiency of operations. It’s been proved that, when system characteristics change, it can cause a significant increase in material handling cost. Consequently, the efficiency of the current layout decreases or is lost and it does necessitate rearrangement. On the other hand, the rearrangement of the workstations may burden a lot of expenses on the system. The problem that considers balance between material handling cost and the rearrangement cost is known as the Dynamic Facility Layout Problem (DFLP). The objective of a DFLP is to find the best layout for the company facilities in each period of planning horizon considering the rearrangement costs. Due to the complex structure of the problem, there are few researches in the literature which tried to find near optimum solutions for DFLP with budget constraint. In t...

Research paper thumbnail of Multi-echelon supply chain network modelling and optimization via simulation and metaheuristic algorithms

Scientia Iranica, 2016

An important problem in todays industries is the cost issue, due to the high level of competition... more An important problem in todays industries is the cost issue, due to the high level of competition in the global market. This fact obliges organizations to focus on improvement of their production-distribution routes, in order to nd the best. The Supply Chain Network (SCN) is one of the, so-called, production-distribution models that has many layers and/or echelons. In this paper, a new SCN, which is more compatible with real world problems is presented, and then, two novel hybrid algorithms have been developed to solve the model. Each hybrid algorithm integrates the simulation technique with two metaheuristic algorithms, including the Genetic Algorithm (GA) and the Simulated Annealing Algorithm (SAA), namely, HSIM-META. The output of the simulation model is inserted as the initial population in tuned-parameter metaheuristic algorithms to nd near optimum solutions, which is in fact a new approach in the literature. To analyze the performance of the proposed algorithms, di erent numerical examples are presented. The computational results of the proposed HSIM-META, including hybrid simulation-GA (HSIM-GA) and hybrid simulation-SAA (HSIM-SAA), are compared to the GA and the SAA. Computational results show that the proposed HSIM-META has suitable accuracy and speed for use in real world applications.

Research paper thumbnail of A New Hybrid Parallel Simulated Annealing Algorithm for Travelling Salesman Problem with Multiple Transporters

Journal of Optimization in Industrial Engineering, 2014

In today’s competitive transportation systems, passengers search to find traveling agencies that ... more In today’s competitive transportation systems, passengers search to find traveling agencies that are able to serve them efficiently considering both traveling time and transportation costs. In this paper, we present a new model for the traveling salesman problem with multiple transporters (TSPMT). In the proposed model, which is more applicable than the traditional versions, each city has different transporting vehicles and the cost of travel through each city is dependent on the transporting vehicles type. The aim is to determine an optimal sequence of visited cities with minimum traveling times by available transporting vehicles within a limited budget. First, the mathematical model of TSPMT is presented. Next, since the problem is NP-hard, a new hybrid parallel simulated annealing algorithm with a new coding scheme is proposed. To analyze the performance of the proposed algorithm, 50 numerical examples with different budget types are examined and solved using the algorithm. The c...

Research paper thumbnail of Multi-echelon supply chain network modelling and optimization via simulation and metaheuristic algorithms

An important problem in todays industries is the cost issue, due to the high level of competition... more An important problem in todays industries is the cost issue, due to the high level of competition in the global market. This fact obliges organizations to focus on improvement of their production-distribution routes, in order to nd the best. The Supply Chain Network (SCN) is one of the, so-called, production-distribution models that has many layers and/or echelons. In this paper, a new SCN, which is more compatible with real world problems is presented, and then, two novel hybrid algorithms have been developed to solve the model. Each hybrid algorithm integrates the simulation technique with two metaheuristic algorithms, including the Genetic Algorithm (GA) and the Simulated Annealing Algorithm (SAA), namely, HSIM-META. The output of the simulation model is inserted as the initial population in tuned-parameter metaheuristic algorithms to nd near optimum solutions, which is in fact a new approach in the literature. To analyze the performance of the proposed algorithms, diierent numerical examples are presented. The computational results of the proposed HSIM-META, including hybrid simulation-GA (HSIM-GA) and hybrid simulation-SAA (HSIM-SAA), are compared to the GA and the SAA. Computational results show that the proposed HSIM-META has suitable accuracy and speed for use in real world applications.