Mustafa Ozbayrak | Bahcesehir University (original) (raw)

Papers by Mustafa Ozbayrak

Proceedings of the 29th conference on Winter simulation - WSC '97, 1997

The objective of this thesis is to study the design and analysis of tool management system in the... more The objective of this thesis is to study the design and analysis of tool management system in the automated manufacturing systems. The thesis is focused on two main areas, namely design and experiment. In the first part of the thesis, the design facility created has been reported. The model has been designed using a hybrid approach in which the power of both algorithmic and knowledge based approaches is utilised. Model permits detail, more accurate and complete solutions for the management of tools in a generic manufacturing system. In the second part of the thesis, to add more understanding to the tool management problems, the interactions of the major tool management design parameters have been investigated using a well known design technique, the Taguchi method. For this purpose, a large number of design experiments have been configured where some have been suggested by the Taguchi method and some have been created by the author to add more confidence, using a large body of real ...

International Journal of Computer Integrated Manufacturing, Feb 19, 2007

This paper reports on a new approach to applying simulated annealing to a class of mixed-model se... more This paper reports on a new approach to applying simulated annealing to a class of mixed-model sequencing problems. Two major problems are considered: (1) minimizing of actual workload from the ideal workload on the assembly lines; (2) minimizing required set-ups on the assembly lines. The approaches that are found to perform the best are extended for the bicriteria problem considering

Proceedings of the 34th Conference on Winter Simulation Exploring New Frontiers, Dec 8, 2002

A medium sized UK based academic publishers own a subsidiary printing business. Presently the Aca... more A medium sized UK based academic publishers own a subsidiary printing business. Presently the Academic Printers (AP) is experiencing productions line flow problems reducing the efficiency of the operation. Most of the problems are generated by the imbalanced workflow through the system. By implementing a JIT production planning system it is hoped that some of the production problems can be

Int J Prod Econ, 2004

... ABC to estimate the manufacturing and product costs in an advanced manufacturing organisation... more ... ABC to estimate the manufacturing and product costs in an advanced manufacturing organisation that ... the major cost items involved in resource consumption in automated manufacturing systems: ... spent to buy machine tools, and cutting tool holders used in machining processes. ...

Robotics and Computer Integrated Manufacturing, Oct 1, 2006

Evolving consumer demand has led to the emergence of a new business era where change plays a domi... more Evolving consumer demand has led to the emergence of a new business era where change plays a dominant role. This new era has in turn posed a number of competences that supply chain systems need to posses so as to survive and prosper under change and uncertainty. The main aim of this work is to model the performance of an make-to-order (MTO) production environment that operates as part of a wider supply chain network under various control policies and identify the best performing ones. A simulation model has been created and used as a tool to help quantify the effects of three control policies on this MTO system. A number of performance metrics such as Work-in-process (WIP), tardiness, responsiveness and mean flow time have been considered to provide further insight into the impact of these three localised control policies. The three control policies implemented were push, and two modes of pull control, which are, CONWIP and tight pull.

International Journal of Computer Integrated Manufacturing - IJCIM, 2003

Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular,... more Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular, tool management is critically important for timely manufacture. Since a large number of tools flow in a medium-size FMS, it is important to design and operate the tool management system (TMS) to guarantee unmanned and streamlined manufacturing. In this work, a new strategy is developed to minimize the tooling cost by recycling the partially used tools within the manufacturing cell. A particular TMS design strategy, entitled workpiece-oriented tool flow, is considered. Under this strategy, three different tool issue sub-strategies are used to assign tools to available machines. These sub-strategies are measured against cell and tooling performance criteria and are compared to each other with and without recycling. Conclusions are drawn for some different cell configurations and the results are highlighted for different performance criteria.

ARCHIVE: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 1989-1996 (vols 203-210), 1996

In many flexible machining cells, total priority is given to meeting a scheduled list of work ord... more In many flexible machining cells, total priority is given to meeting a scheduled list of work orders. The management of the tooling resource required to process these work schedules is also important. This paper presents and investigates strategies for tool management and job allocation in such a demand-driven system, and are termed work oriented. These generic strategies are described, forecasting the required level of tool exchange activity at individual machines according to different sets of issue and return rules. A computational study using industrial data has been conducted to assess the effectiveness of the strategies over a range of different system characteristics and under the influence of two job allocation rules. The model, data and range of parameters are discussed and results are presented and compared. Conclusions are drawn regarding the success of the study, the nature of the data used and the relative performance of the strategies.

Journal of Manufacturing Technology Management, 2004

The quality of health care is increasingly receiving more and more emphases in almost all develop... more The quality of health care is increasingly receiving more and more emphases in almost all developed countries. Traditional health care Quality Assurance (QA) models have always been implemented in retrospect depending heavily on surveys. The objective of this research is to develop a ...

A medium sized UK based academic publishers own a subsidiary printing business. Presently the Aca... more A medium sized UK based academic publishers own a subsidiary printing business. Presently the Academic Printers (AP) is experiencing productions line flow problems reducing the efficiency of the operation. Most of the problems are generated by the imbalanced workflow through the system. By implementing a JIT production planning system it is hoped that some of the production problems can be

Geochimica Et Cosmochimica Acta, 2005

International Journal of Computer Integrated Manufacturing, 2006

This paper reports on a new approach to applying simulated annealing to a class of mixed-model se... more This paper reports on a new approach to applying simulated annealing to a class of mixed-model sequencing problems. Two major problems are considered: (1) minimizing of actual workload from the ideal workload on the assembly lines; (2) minimizing required set-ups on the assembly lines. The approaches that are found to perform the best are extended for the bicriteria problem considering problems 1 and 2. The sequencing of mixed-model assembly lines in a just-in-time (JIT) production environment is a well-known combinatorial optimization problem. The main purpose of this paper is to use the simulated annealing methodology to schedule JIT production lines. The performance of the proposed method is tested on several problems from the literature and is compared with optimal solutions found so far. Finally, it is shown that solutions obtained by the proposed method are superior to the formal optimal solution. The performance of the method is numerically tested on a standard problem.

International Journal of Production Economics, 2006

It is a common practice to measure the performance of a manufacturing system using common product... more It is a common practice to measure the performance of a manufacturing system using common production management criteria such as cell performance metrics or general operations management metrics among engineering management/business administration practitioners. However, most of the time, these performance measures do not truly reflect company's financial performance. It is not unusual to see a well performing operational strategy in terms of one or more cell performance metrics fail to produce the same level of financial performance. The aim of this study is to investigate the effects of the two most common manufacturing planning and control strategies, namely push and pull, on the cash conversion cycle (CCC) in a manufacturing system. The CCC is an important measure of the length of time between cash payment for the purchase of resalable goods or an investment made for production and the collection of accounts receivable generated by the sale of those purchased/produced goods. We have simulated a hypothetical multi-stage manufacturing system that is run under either push or pull control systems to measure the effects of these systems on the financial performance of the company. We used deterministic master production scheduling for the simulated production period to eliminate the variation generated by randomness so that a one-to-one comparison between manufacturing control strategies is made possible. We analyse the results generated by the two control strategies to understand their effects on the CCC and draw conclusions.

Journal of Manufacturing Technology Management, 2004

Scheduling a manufacturing system can be one of the most complex tasks in managing an operation. ... more Scheduling a manufacturing system can be one of the most complex tasks in managing an operation. Planning and control systems such as just in time (JIT) can aid scheduling. However, planning and control tools require a fairly stable shopfloor environment to get the best out of them. Many system designs and schedules only consider 100 per cent reliability in machines,

Robotics and Computer-integrated Manufacturing, 2006

Evolving consumer demand has led to the emergence of a new business era where change plays a domi... more Evolving consumer demand has led to the emergence of a new business era where change plays a dominant role. This new era has in turn posed a number of competences that supply chain systems need to posses so as to survive and prosper under change and uncertainty. The main aim of this work is to model the performance of an make-to-order (MTO) production environment that operates as part of a wider supply chain network under various control policies and identify the best performing ones. A simulation model has been created and used as a tool to help quantify the effects of three control policies on this MTO system. A number of performance metrics such as Work-in-process (WIP), tardiness, responsiveness and mean flow time have been considered to provide further insight into the impact of these three localised control policies. The three control policies implemented were push, and two modes of pull control, which are, CONWIP and tight pull.

International Journal of Advanced Manufacturing Technology, 2006

In this paper, the effects of various dispatching rules on the operation and performance of cellu... more In this paper, the effects of various dispatching rules on the operation and performance of cellular manufacturing systems (CMS) are evaluated. When the study of a CMS considers the automated material handling, it is crucial to reduce the gridlock probability (i.e., the probability of an unsuccessful load transfer attempt occurring in the interface point between the intercell and intracell handling system). Preventing an unsuccessful load transfer is critical for the operation of the entire system as a blockage between the automated guided vehicle (AGV) and the overloaded cell results in a total system shutdown. The gridlock probability is influenced by the dispatching rule used to schedule the load transfers in the system. Therefore, in order to reduce this probability it is necessary to use a dispatching rule that will decrease the number of waiting loads in the transfer spurs. The main objective of the paper presented herein is to identify a dispatching rule that maintains the system operational at all times. A group of dispatching rules, including the first come first served (FCFS), shortest imminent operation (SI), longest imminent operation (LI), most remaining operations (MRO), shortest processing time (SPT), shortest remaining process time (SR), and a newly developed rule proposed by the authors, loads with the minimum number of processing first (MNP), are tested and evaluated with respect to whether the capacity of the transfer spurs of the cells is exceeded. This paper presents a simulation model of a cellular manufacturing system, which is used to further explore the effects of the dispatching rules on the system performance. The results show superior performance of the newly proposed MNP rule.

International Journal of Computer Integrated Manufacturing, 2003

Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular,... more Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular, tool management is critically important for timely manufacture. Since a large number of tools flow in a medium-size FMS, it is important to design and operate the tool management system (TMS) to guarantee unmanned and streamlined manufacturing. In this work, a new strategy is developed to minimize the tooling cost by recycling the partially used tools within the manufacturing cell. A particular TMS design strategy, entitled workpiece-oriented tool flow, is considered. Under this strategy, three different tool issue sub-strategies are used to assign tools to available machines. These sub-strategies are measured against cell and tooling performance criteria and are compared to each other with and without recycling. Conclusions are drawn for some different cell configurations and the results are highlighted for different performance criteria.

Proceedings of the 29th conference on Winter simulation - WSC '97, 1997

The objective of this thesis is to study the design and analysis of tool management system in the... more The objective of this thesis is to study the design and analysis of tool management system in the automated manufacturing systems. The thesis is focused on two main areas, namely design and experiment. In the first part of the thesis, the design facility created has been reported. The model has been designed using a hybrid approach in which the power of both algorithmic and knowledge based approaches is utilised. Model permits detail, more accurate and complete solutions for the management of tools in a generic manufacturing system. In the second part of the thesis, to add more understanding to the tool management problems, the interactions of the major tool management design parameters have been investigated using a well known design technique, the Taguchi method. For this purpose, a large number of design experiments have been configured where some have been suggested by the Taguchi method and some have been created by the author to add more confidence, using a large body of real ...

International Journal of Computer Integrated Manufacturing, Feb 19, 2007

This paper reports on a new approach to applying simulated annealing to a class of mixed-model se... more This paper reports on a new approach to applying simulated annealing to a class of mixed-model sequencing problems. Two major problems are considered: (1) minimizing of actual workload from the ideal workload on the assembly lines; (2) minimizing required set-ups on the assembly lines. The approaches that are found to perform the best are extended for the bicriteria problem considering

Proceedings of the 34th Conference on Winter Simulation Exploring New Frontiers, Dec 8, 2002

A medium sized UK based academic publishers own a subsidiary printing business. Presently the Aca... more A medium sized UK based academic publishers own a subsidiary printing business. Presently the Academic Printers (AP) is experiencing productions line flow problems reducing the efficiency of the operation. Most of the problems are generated by the imbalanced workflow through the system. By implementing a JIT production planning system it is hoped that some of the production problems can be

Int J Prod Econ, 2004

... ABC to estimate the manufacturing and product costs in an advanced manufacturing organisation... more ... ABC to estimate the manufacturing and product costs in an advanced manufacturing organisation that ... the major cost items involved in resource consumption in automated manufacturing systems: ... spent to buy machine tools, and cutting tool holders used in machining processes. ...

Robotics and Computer Integrated Manufacturing, Oct 1, 2006

Evolving consumer demand has led to the emergence of a new business era where change plays a domi... more Evolving consumer demand has led to the emergence of a new business era where change plays a dominant role. This new era has in turn posed a number of competences that supply chain systems need to posses so as to survive and prosper under change and uncertainty. The main aim of this work is to model the performance of an make-to-order (MTO) production environment that operates as part of a wider supply chain network under various control policies and identify the best performing ones. A simulation model has been created and used as a tool to help quantify the effects of three control policies on this MTO system. A number of performance metrics such as Work-in-process (WIP), tardiness, responsiveness and mean flow time have been considered to provide further insight into the impact of these three localised control policies. The three control policies implemented were push, and two modes of pull control, which are, CONWIP and tight pull.

International Journal of Computer Integrated Manufacturing - IJCIM, 2003

Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular,... more Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular, tool management is critically important for timely manufacture. Since a large number of tools flow in a medium-size FMS, it is important to design and operate the tool management system (TMS) to guarantee unmanned and streamlined manufacturing. In this work, a new strategy is developed to minimize the tooling cost by recycling the partially used tools within the manufacturing cell. A particular TMS design strategy, entitled workpiece-oriented tool flow, is considered. Under this strategy, three different tool issue sub-strategies are used to assign tools to available machines. These sub-strategies are measured against cell and tooling performance criteria and are compared to each other with and without recycling. Conclusions are drawn for some different cell configurations and the results are highlighted for different performance criteria.

ARCHIVE: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 1989-1996 (vols 203-210), 1996

In many flexible machining cells, total priority is given to meeting a scheduled list of work ord... more In many flexible machining cells, total priority is given to meeting a scheduled list of work orders. The management of the tooling resource required to process these work schedules is also important. This paper presents and investigates strategies for tool management and job allocation in such a demand-driven system, and are termed work oriented. These generic strategies are described, forecasting the required level of tool exchange activity at individual machines according to different sets of issue and return rules. A computational study using industrial data has been conducted to assess the effectiveness of the strategies over a range of different system characteristics and under the influence of two job allocation rules. The model, data and range of parameters are discussed and results are presented and compared. Conclusions are drawn regarding the success of the study, the nature of the data used and the relative performance of the strategies.

Journal of Manufacturing Technology Management, 2004

The quality of health care is increasingly receiving more and more emphases in almost all develop... more The quality of health care is increasingly receiving more and more emphases in almost all developed countries. Traditional health care Quality Assurance (QA) models have always been implemented in retrospect depending heavily on surveys. The objective of this research is to develop a ...

A medium sized UK based academic publishers own a subsidiary printing business. Presently the Aca... more A medium sized UK based academic publishers own a subsidiary printing business. Presently the Academic Printers (AP) is experiencing productions line flow problems reducing the efficiency of the operation. Most of the problems are generated by the imbalanced workflow through the system. By implementing a JIT production planning system it is hoped that some of the production problems can be

Geochimica Et Cosmochimica Acta, 2005

International Journal of Computer Integrated Manufacturing, 2006

This paper reports on a new approach to applying simulated annealing to a class of mixed-model se... more This paper reports on a new approach to applying simulated annealing to a class of mixed-model sequencing problems. Two major problems are considered: (1) minimizing of actual workload from the ideal workload on the assembly lines; (2) minimizing required set-ups on the assembly lines. The approaches that are found to perform the best are extended for the bicriteria problem considering problems 1 and 2. The sequencing of mixed-model assembly lines in a just-in-time (JIT) production environment is a well-known combinatorial optimization problem. The main purpose of this paper is to use the simulated annealing methodology to schedule JIT production lines. The performance of the proposed method is tested on several problems from the literature and is compared with optimal solutions found so far. Finally, it is shown that solutions obtained by the proposed method are superior to the formal optimal solution. The performance of the method is numerically tested on a standard problem.

International Journal of Production Economics, 2006

It is a common practice to measure the performance of a manufacturing system using common product... more It is a common practice to measure the performance of a manufacturing system using common production management criteria such as cell performance metrics or general operations management metrics among engineering management/business administration practitioners. However, most of the time, these performance measures do not truly reflect company's financial performance. It is not unusual to see a well performing operational strategy in terms of one or more cell performance metrics fail to produce the same level of financial performance. The aim of this study is to investigate the effects of the two most common manufacturing planning and control strategies, namely push and pull, on the cash conversion cycle (CCC) in a manufacturing system. The CCC is an important measure of the length of time between cash payment for the purchase of resalable goods or an investment made for production and the collection of accounts receivable generated by the sale of those purchased/produced goods. We have simulated a hypothetical multi-stage manufacturing system that is run under either push or pull control systems to measure the effects of these systems on the financial performance of the company. We used deterministic master production scheduling for the simulated production period to eliminate the variation generated by randomness so that a one-to-one comparison between manufacturing control strategies is made possible. We analyse the results generated by the two control strategies to understand their effects on the CCC and draw conclusions.

Journal of Manufacturing Technology Management, 2004

Scheduling a manufacturing system can be one of the most complex tasks in managing an operation. ... more Scheduling a manufacturing system can be one of the most complex tasks in managing an operation. Planning and control systems such as just in time (JIT) can aid scheduling. However, planning and control tools require a fairly stable shopfloor environment to get the best out of them. Many system designs and schedules only consider 100 per cent reliability in machines,

Robotics and Computer-integrated Manufacturing, 2006

Evolving consumer demand has led to the emergence of a new business era where change plays a domi... more Evolving consumer demand has led to the emergence of a new business era where change plays a dominant role. This new era has in turn posed a number of competences that supply chain systems need to posses so as to survive and prosper under change and uncertainty. The main aim of this work is to model the performance of an make-to-order (MTO) production environment that operates as part of a wider supply chain network under various control policies and identify the best performing ones. A simulation model has been created and used as a tool to help quantify the effects of three control policies on this MTO system. A number of performance metrics such as Work-in-process (WIP), tardiness, responsiveness and mean flow time have been considered to provide further insight into the impact of these three localised control policies. The three control policies implemented were push, and two modes of pull control, which are, CONWIP and tight pull.

International Journal of Advanced Manufacturing Technology, 2006

In this paper, the effects of various dispatching rules on the operation and performance of cellu... more In this paper, the effects of various dispatching rules on the operation and performance of cellular manufacturing systems (CMS) are evaluated. When the study of a CMS considers the automated material handling, it is crucial to reduce the gridlock probability (i.e., the probability of an unsuccessful load transfer attempt occurring in the interface point between the intercell and intracell handling system). Preventing an unsuccessful load transfer is critical for the operation of the entire system as a blockage between the automated guided vehicle (AGV) and the overloaded cell results in a total system shutdown. The gridlock probability is influenced by the dispatching rule used to schedule the load transfers in the system. Therefore, in order to reduce this probability it is necessary to use a dispatching rule that will decrease the number of waiting loads in the transfer spurs. The main objective of the paper presented herein is to identify a dispatching rule that maintains the system operational at all times. A group of dispatching rules, including the first come first served (FCFS), shortest imminent operation (SI), longest imminent operation (LI), most remaining operations (MRO), shortest processing time (SPT), shortest remaining process time (SR), and a newly developed rule proposed by the authors, loads with the minimum number of processing first (MNP), are tested and evaluated with respect to whether the capacity of the transfer spurs of the cells is exceeded. This paper presents a simulation model of a cellular manufacturing system, which is used to further explore the effects of the dispatching rules on the system performance. The results show superior performance of the newly proposed MNP rule.

International Journal of Computer Integrated Manufacturing, 2003

Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular,... more Flexible manufacturing systems (FMS) are complex, with a high variety of entities. In particular, tool management is critically important for timely manufacture. Since a large number of tools flow in a medium-size FMS, it is important to design and operate the tool management system (TMS) to guarantee unmanned and streamlined manufacturing. In this work, a new strategy is developed to minimize the tooling cost by recycling the partially used tools within the manufacturing cell. A particular TMS design strategy, entitled workpiece-oriented tool flow, is considered. Under this strategy, three different tool issue sub-strategies are used to assign tools to available machines. These sub-strategies are measured against cell and tooling performance criteria and are compared to each other with and without recycling. Conclusions are drawn for some different cell configurations and the results are highlighted for different performance criteria.