Production planning decisions are usually made by human planners that are assisted by decision su... more Production planning decisions are usually made by human planners that are assisted by decision support systems. While it is widely argued in the literature that current decision support systems for production planning are generally inadequate, it is not clear to what extent human planners actually disregard the planning decisions proposed by the system. In this study, we investigate this question. In a setting in which the planning system's model has an adequate representation of reality, we collect data on actual planning decisions and compare them to the planning decisions proposed by the system.
International Journal of Operations & Production Management, 1996
Production scheduling, which is a part of the planning and control of individual production units... more Production scheduling, which is a part of the planning and control of individual production units, lies at the very heart of the performance of manufacturing organizations. The need for efficient scheduling has greatly increased in recent decades owing to market demands for product quality, flexibility and order flow times. However, although scheduling research activities have in the same period moved from purely academic exercises to serious attempts to solve real-world problems, successful implementations of scheduling techniques in practice are still scarce . Moreover, most of the existing successful implementations have only been realized in highly controlled production processes such as massassembly and the (semi-)process industry. Therefore, in many companies, scheduling is still a typically human domain. However, the task of scheduling production units can become very complex. Humans are not very well equipped to control or optimize large and complex systems, and the relations between actions and effects are very difficult to assess. Hence, practitioners in production planning and control are often convinced that much can be improved with regard to manual scheduling. This paper will focus on problems that are related to the complexity of scheduling in practice. Techniques and information systems based on these techniques are commonly regarded as means to improve scheduling. However, because of the complexity of scheduling in practice, implementing these systems has created many problems. Schedules based on these techniques are often changed by the scheduler or are not carried out exactly on the shopfloor; they are often based on a simplified representation of the shopfloor, and therefore are possibly violating constraints. Also, some techniques cannot account for disturbances without completely regenerating the schedule. This can lead to unacceptable response times and nervous scheduling behaviour. Because the quality of a schedule is very hard to assess, the advantages of a scheduling technique are hard to prove to schedulers and the operators on the shopfloor. Therefore, these techniques are easily overruled by the scheduler and the shopfloor operators. The specific strengths and weaknesses of human cognition are often underemphazised when implementing scheduling techniques.
The theory and practice of what has traditionally been called scheduling have been relatively clo... more The theory and practice of what has traditionally been called scheduling have been relatively close in some domains, while remaining worlds apart in others. Success at higher levels of production control has often been seen where the execution issues can be glossed over, especially in industries where there are prolonged periods of stability and maturity. Scheduling theory at the detailed level has been particularly successful in process industries or in situations where there are relatively few machines with significant setup issues. Unfortunately, the theory and practice have not been close in intermittent job shops or industries where there is inherent uncertainty or human judgment is necessary. This paper discusses the traditional scheduling problem and develops a framework based on the practice of scheduling that assists in understanding the requirements for an extended definition of scheduling that goes beyond the sequencing problem.
Abstract The first three steps of a new design method for decision support systems in production ... more Abstract The first three steps of a new design method for decision support systems in production scheduling tasks are applied to a large bulk terminal. The operational characteristics of the company largely correspond with those of typical semiprocess ...
This article describes the implementation of information systems to support the production planni... more This article describes the implementation of information systems to support the production planning and scheduling functions in two steel processing business units of a steel plant. In particular, the integration of the implementation of two systems is described: Enterprise Resource Planning (ERP) and Advanced Planning and Scheduling (APS). The article presents a functional architecture that integrates the two systems, and discusses typical issues that have to be solved when ERP and APS systems have to be integrated. Lessons learnt included the importance of an architecture to facilitate discussions, issue management, the importance of the primary process, diÄerences between an ERP and APS implementation and differences in process descriptions.
Omega-international Journal of Management Science, 1997
This paper presents a review on the applicability of scheduling techniques in practice. Both the ... more This paper presents a review on the applicability of scheduling techniques in practice. Both the operations research and the artificial intelligence research communities have produced a number of reports on the applicability of techniques, often in isolation from each other, although the problems encountered seem largely similar in each case. Moreover, studies on the role of humans in production scheduling are reviewed. Papers that discuss the use of techniques by humans are also discussed. The paper suggests ways in which the applicability of scheduling techniques might be improved.
"What is the difference between planning and scheduling?" Production control encompasses many tas... more "What is the difference between planning and scheduling?" Production control encompasses many tasks performed by humans, three of which are planning, scheduling, and dispatching. In the past, the only criterion that could distinguish between the tasks was that planning is usually on a higher level than scheduling and scheduling is on a higher level than dispatching. Hence, the tasks are often ambiguous, unclear, and subject to speculation. There are few formal studies on the actual tasks of planning, scheduling, and dispatching, and there are no known studies that compare or discuss all three. In this paper it is argued that it is important to understand the differences between the tasks. An action science and ethnographic case study is presented as the empirical basis for the discussion, and the implications for decision support systems in production control tasks are presented.
Standard software for decision support in production control tasks is commonly structured accordi... more Standard software for decision support in production control tasks is commonly structured according to the hierarchical production planning (HPP) concept. However, in a focused factory one planner may carry out planning, scheduling and dispatching. This paper presents a case study ...
In this chapter, we will review the research conducted on the human factor in planning and schedu... more In this chapter, we will review the research conducted on the human factor in planning and scheduling. Specifically, the positive and negative aspects of the human factor will be discussed. We will also discuss the consequences when these aspects are ignored or overlooked by the formal or systemized solutions.
Production planning decisions are usually made by human planners that are assisted by decision su... more Production planning decisions are usually made by human planners that are assisted by decision support systems. While it is widely argued in the literature that current decision support systems for production planning are generally inadequate, it is not clear to what ...
Production scheduling in industrial practice is still primarily a manual task, despite immense re... more Production scheduling in industrial practice is still primarily a manual task, despite immense research efforts and the fact that manual scheduling is a very complex task. In this paper, the allocation of tasks between scheduling systems and human schedulers for various types ...
The complexity of planning tasks have increased over the past decade. There is relatively poor un... more The complexity of planning tasks have increased over the past decade. There is relatively poor understanding what the implications are of increased task complexity in planning and scheduling operations. Previous work in the behavorial sciences have investigated the concept of cognitive load, addressing both task complecity and task workload or stress, and have concluded that decision makers tend to resort to routine action and reduce the variety in their actions with increasing complexity and workload. Alternatively, control theory suggests that a higher variety of actions is needed to deal with more complex problems. In this paper, we investigate the effects of task complexity in a chemical plant on the variety of actions deployed by the planners. The single work center resource structure and the availability of actual planning data from an ERP system allows us to both use field data and study a situation which is simple enough to measure the main effect. Our results suggest that increased task complexity without time pressure does indeed lead to increased action variety deployed by the planners.
Production planning and control fulfill a crucial role in enterprises. Planning and scheduling ac... more Production planning and control fulfill a crucial role in enterprises. Planning and scheduling activities are very complex, and take place within the enterprise and across the entire supply chain in order to achieve high quality products at lower cost, lower inventory and higher levels of customer service. Since the information that has to be processed in planning and scheduling functions is very complex information technology is used extensively to support these functions. In the field of manufacturing planning and control Decision Support Systems (DSS) are used. Those are also known as Advanced Planning Systems (APS).
In companies where Advanced Planning and Scheduling (APS) systems are implemented, planning and s... more In companies where Advanced Planning and Scheduling (APS) systems are implemented, planning and scheduling decisions are often transferred from the shop floor to the new APS system. As a result, there can be disagreement between the scheduler and the shop floor ...
Production planning decisions are usually made by human planners that are assisted by decision su... more Production planning decisions are usually made by human planners that are assisted by decision support systems. While it is widely argued in the literature that current decision support systems for production planning are generally inadequate, it is not clear to what extent human planners actually disregard the planning decisions proposed by the system. In this study, we investigate this question. In a setting in which the planning system's model has an adequate representation of reality, we collect data on actual planning decisions and compare them to the planning decisions proposed by the system.
International Journal of Operations & Production Management, 1996
Production scheduling, which is a part of the planning and control of individual production units... more Production scheduling, which is a part of the planning and control of individual production units, lies at the very heart of the performance of manufacturing organizations. The need for efficient scheduling has greatly increased in recent decades owing to market demands for product quality, flexibility and order flow times. However, although scheduling research activities have in the same period moved from purely academic exercises to serious attempts to solve real-world problems, successful implementations of scheduling techniques in practice are still scarce . Moreover, most of the existing successful implementations have only been realized in highly controlled production processes such as massassembly and the (semi-)process industry. Therefore, in many companies, scheduling is still a typically human domain. However, the task of scheduling production units can become very complex. Humans are not very well equipped to control or optimize large and complex systems, and the relations between actions and effects are very difficult to assess. Hence, practitioners in production planning and control are often convinced that much can be improved with regard to manual scheduling. This paper will focus on problems that are related to the complexity of scheduling in practice. Techniques and information systems based on these techniques are commonly regarded as means to improve scheduling. However, because of the complexity of scheduling in practice, implementing these systems has created many problems. Schedules based on these techniques are often changed by the scheduler or are not carried out exactly on the shopfloor; they are often based on a simplified representation of the shopfloor, and therefore are possibly violating constraints. Also, some techniques cannot account for disturbances without completely regenerating the schedule. This can lead to unacceptable response times and nervous scheduling behaviour. Because the quality of a schedule is very hard to assess, the advantages of a scheduling technique are hard to prove to schedulers and the operators on the shopfloor. Therefore, these techniques are easily overruled by the scheduler and the shopfloor operators. The specific strengths and weaknesses of human cognition are often underemphazised when implementing scheduling techniques.
The theory and practice of what has traditionally been called scheduling have been relatively clo... more The theory and practice of what has traditionally been called scheduling have been relatively close in some domains, while remaining worlds apart in others. Success at higher levels of production control has often been seen where the execution issues can be glossed over, especially in industries where there are prolonged periods of stability and maturity. Scheduling theory at the detailed level has been particularly successful in process industries or in situations where there are relatively few machines with significant setup issues. Unfortunately, the theory and practice have not been close in intermittent job shops or industries where there is inherent uncertainty or human judgment is necessary. This paper discusses the traditional scheduling problem and develops a framework based on the practice of scheduling that assists in understanding the requirements for an extended definition of scheduling that goes beyond the sequencing problem.
Abstract The first three steps of a new design method for decision support systems in production ... more Abstract The first three steps of a new design method for decision support systems in production scheduling tasks are applied to a large bulk terminal. The operational characteristics of the company largely correspond with those of typical semiprocess ...
This article describes the implementation of information systems to support the production planni... more This article describes the implementation of information systems to support the production planning and scheduling functions in two steel processing business units of a steel plant. In particular, the integration of the implementation of two systems is described: Enterprise Resource Planning (ERP) and Advanced Planning and Scheduling (APS). The article presents a functional architecture that integrates the two systems, and discusses typical issues that have to be solved when ERP and APS systems have to be integrated. Lessons learnt included the importance of an architecture to facilitate discussions, issue management, the importance of the primary process, diÄerences between an ERP and APS implementation and differences in process descriptions.
Omega-international Journal of Management Science, 1997
This paper presents a review on the applicability of scheduling techniques in practice. Both the ... more This paper presents a review on the applicability of scheduling techniques in practice. Both the operations research and the artificial intelligence research communities have produced a number of reports on the applicability of techniques, often in isolation from each other, although the problems encountered seem largely similar in each case. Moreover, studies on the role of humans in production scheduling are reviewed. Papers that discuss the use of techniques by humans are also discussed. The paper suggests ways in which the applicability of scheduling techniques might be improved.
"What is the difference between planning and scheduling?" Production control encompasses many tas... more "What is the difference between planning and scheduling?" Production control encompasses many tasks performed by humans, three of which are planning, scheduling, and dispatching. In the past, the only criterion that could distinguish between the tasks was that planning is usually on a higher level than scheduling and scheduling is on a higher level than dispatching. Hence, the tasks are often ambiguous, unclear, and subject to speculation. There are few formal studies on the actual tasks of planning, scheduling, and dispatching, and there are no known studies that compare or discuss all three. In this paper it is argued that it is important to understand the differences between the tasks. An action science and ethnographic case study is presented as the empirical basis for the discussion, and the implications for decision support systems in production control tasks are presented.
Standard software for decision support in production control tasks is commonly structured accordi... more Standard software for decision support in production control tasks is commonly structured according to the hierarchical production planning (HPP) concept. However, in a focused factory one planner may carry out planning, scheduling and dispatching. This paper presents a case study ...
In this chapter, we will review the research conducted on the human factor in planning and schedu... more In this chapter, we will review the research conducted on the human factor in planning and scheduling. Specifically, the positive and negative aspects of the human factor will be discussed. We will also discuss the consequences when these aspects are ignored or overlooked by the formal or systemized solutions.
Production planning decisions are usually made by human planners that are assisted by decision su... more Production planning decisions are usually made by human planners that are assisted by decision support systems. While it is widely argued in the literature that current decision support systems for production planning are generally inadequate, it is not clear to what ...
Production scheduling in industrial practice is still primarily a manual task, despite immense re... more Production scheduling in industrial practice is still primarily a manual task, despite immense research efforts and the fact that manual scheduling is a very complex task. In this paper, the allocation of tasks between scheduling systems and human schedulers for various types ...
The complexity of planning tasks have increased over the past decade. There is relatively poor un... more The complexity of planning tasks have increased over the past decade. There is relatively poor understanding what the implications are of increased task complexity in planning and scheduling operations. Previous work in the behavorial sciences have investigated the concept of cognitive load, addressing both task complecity and task workload or stress, and have concluded that decision makers tend to resort to routine action and reduce the variety in their actions with increasing complexity and workload. Alternatively, control theory suggests that a higher variety of actions is needed to deal with more complex problems. In this paper, we investigate the effects of task complexity in a chemical plant on the variety of actions deployed by the planners. The single work center resource structure and the availability of actual planning data from an ERP system allows us to both use field data and study a situation which is simple enough to measure the main effect. Our results suggest that increased task complexity without time pressure does indeed lead to increased action variety deployed by the planners.
Production planning and control fulfill a crucial role in enterprises. Planning and scheduling ac... more Production planning and control fulfill a crucial role in enterprises. Planning and scheduling activities are very complex, and take place within the enterprise and across the entire supply chain in order to achieve high quality products at lower cost, lower inventory and higher levels of customer service. Since the information that has to be processed in planning and scheduling functions is very complex information technology is used extensively to support these functions. In the field of manufacturing planning and control Decision Support Systems (DSS) are used. Those are also known as Advanced Planning Systems (APS).
In companies where Advanced Planning and Scheduling (APS) systems are implemented, planning and s... more In companies where Advanced Planning and Scheduling (APS) systems are implemented, planning and scheduling decisions are often transferred from the shop floor to the new APS system. As a result, there can be disagreement between the scheduler and the shop floor ...
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