ABSTRACT In this paper, we explore the difference between preemption and activity splitting in th... more ABSTRACT In this paper, we explore the difference between preemption and activity splitting in the resource-constrained project scheduling problem (RCPSP) literature and identify a new set of RCPSPs that only allows non-preemptive activity splitting. Each activity can be processed in multiple modes and both renewable and non-renewable resources are considered. Renewable resources have time-varying resource constraints and vacations. Multi-mode RCPSP (MRCPSP) with non-preemptive activity splitting is shown to be a generalization of the RCPSP with calendarization. Activity ready times and due dates are considered to study the impact on project makespan. Computational experiments are conducted to compare optimal makespans under three different problem settings: RCPSPs without activity splitting (P1), RCPSPs with non-preemptive activity splitting (P2), and preemptive RCPSPs (P3). A precedence tree-based branch-and-bound algorithm is modified as an exact method to find optimal solutions. Resource constraints are included into the general time window rule and priority rule-based simple heuristics are proposed to search for good initial solutions to tighten bounding rules. Results indicate that there are significant makespan reductions possible when non-preemptive activity splitting or preemptions are allowed. The higher the range of time-varying renewable resource limits and the tighter the renewable resource limits are, the bigger the resulting makespan reduction can be.
The primary goal of our proposed research effort is to develop solution methodologies for minimiz... more The primary goal of our proposed research effort is to develop solution methodologies for minimizing total weighted tardiness (TWT) for wafer fabrication facilities. We have taken the first steps towards this goal. In Mason et al. [1], we extended the classical job shop work of Pinedo and Singer [2] and developed a disjunctive graph formulation of the problem. Unlike previous job shop scheduling efforts, our disjunctive graph formulation accounts for batching tools, tool groups (identical machines operating in parallel), sequence-dependent setup times, and recirculating product flow. We provide some computational results that show the effectiveness of our approach.
All military organizations depend on the reliable performance of repairable systems for the succe... more All military organizations depend on the reliable performance of repairable systems for the successful completion of missions. Due to limitations in maintenance resources, a maintenance manager must decide how to allocate available resources. This allocation falls within the domain of selective maintenance. Selective maintenance is defined as the process of identifying the subset of maintenance activities to perform from a set of desired maintenance actions. Previously, researchers developed a class of mathematical models that can be used to identify selective maintenance decisions for the following scenario. A system has just completed a mission and will begin its next mission soon. Maintenance cannot be performed during missions; therefore, the decision-maker must decide which components to maintain prior to the next mission. The selective maintenance models considered to date treat decision-making for binary-state systems (i.e. all components, subsystems, and the system itself ar...
In this paper, we study a design problem found in wafer fabs. Different orders are grouped into o... more In this paper, we study a design problem found in wafer fabs. Different orders are grouped into one job because or- ders of an individual customer very often fill only a portion of a Front-Opening Unified Pod (FOUP). A FOUP is as- signed to each job and is used to move the job throughout the wafer fab after job formation.
Proceedings of the Winter Simulation Conference, 2002
... 159-163. Chance, F. 1996. Factory Explorer® users' guide. Hopp, WJ and ML Spearman. 1996... more ... 159-163. Chance, F. 1996. Factory Explorer® users' guide. Hopp, WJ and ML Spearman. 1996.Factory physics; foundation of manufacturing management. Chicago: Irwin. Sze, SM 1985. Semiconductor Devices: Physics and Technology. New York: John Wiley & Sons. ...
ABSTRACT We investigate the integrated production and distribution scheduling problem in a supply... more ABSTRACT We investigate the integrated production and distribution scheduling problem in a supply chain. The manufacturer's production environment is modeled as a parallel machine system. A single capacitated vehicle is employed to deliver products in batches to multiple customers. The scheduling problem can also be viewed as either parallel machines with delivery considerations or a flexible flowshop. Different inventory holding costs, job sizes (volume or storage space required in the transportation unit), and job priorities are taken into account. Efficient mathematical modeling and near-optimal heuristic approaches are presented for minimizing total weighted completion time.
Transportation Research Part E: Logistics and Transportation Review, 2014
ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model... more ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model in which an interdictor chooses a limited amount of elements to attack first on a given network, and then an operator dispatches trains through the residual network. Our MIP model explicitly incorporates discrete unit flows of trains on the rail network with time-variant capacities. A real coal rail transportation network is used in order to generate scenarios to provide tactical and operational level vulnerability assessment analysis including rerouting decisions, travel and delay costs analysis, and the frequency of interdictions of facilities for the dynamic rail system.
ABSTRACT In this paper, we explore the difference between preemption and activity splitting in th... more ABSTRACT In this paper, we explore the difference between preemption and activity splitting in the resource-constrained project scheduling problem (RCPSP) literature and identify a new set of RCPSPs that only allows non-preemptive activity splitting. Each activity can be processed in multiple modes and both renewable and non-renewable resources are considered. Renewable resources have time-varying resource constraints and vacations. Multi-mode RCPSP (MRCPSP) with non-preemptive activity splitting is shown to be a generalization of the RCPSP with calendarization. Activity ready times and due dates are considered to study the impact on project makespan. Computational experiments are conducted to compare optimal makespans under three different problem settings: RCPSPs without activity splitting (P1), RCPSPs with non-preemptive activity splitting (P2), and preemptive RCPSPs (P3). A precedence tree-based branch-and-bound algorithm is modified as an exact method to find optimal solutions. Resource constraints are included into the general time window rule and priority rule-based simple heuristics are proposed to search for good initial solutions to tighten bounding rules. Results indicate that there are significant makespan reductions possible when non-preemptive activity splitting or preemptions are allowed. The higher the range of time-varying renewable resource limits and the tighter the renewable resource limits are, the bigger the resulting makespan reduction can be.
The primary goal of our proposed research effort is to develop solution methodologies for minimiz... more The primary goal of our proposed research effort is to develop solution methodologies for minimizing total weighted tardiness (TWT) for wafer fabrication facilities. We have taken the first steps towards this goal. In Mason et al. [1], we extended the classical job shop work of Pinedo and Singer [2] and developed a disjunctive graph formulation of the problem. Unlike previous job shop scheduling efforts, our disjunctive graph formulation accounts for batching tools, tool groups (identical machines operating in parallel), sequence-dependent setup times, and recirculating product flow. We provide some computational results that show the effectiveness of our approach.
All military organizations depend on the reliable performance of repairable systems for the succe... more All military organizations depend on the reliable performance of repairable systems for the successful completion of missions. Due to limitations in maintenance resources, a maintenance manager must decide how to allocate available resources. This allocation falls within the domain of selective maintenance. Selective maintenance is defined as the process of identifying the subset of maintenance activities to perform from a set of desired maintenance actions. Previously, researchers developed a class of mathematical models that can be used to identify selective maintenance decisions for the following scenario. A system has just completed a mission and will begin its next mission soon. Maintenance cannot be performed during missions; therefore, the decision-maker must decide which components to maintain prior to the next mission. The selective maintenance models considered to date treat decision-making for binary-state systems (i.e. all components, subsystems, and the system itself ar...
In this paper, we study a design problem found in wafer fabs. Different orders are grouped into o... more In this paper, we study a design problem found in wafer fabs. Different orders are grouped into one job because or- ders of an individual customer very often fill only a portion of a Front-Opening Unified Pod (FOUP). A FOUP is as- signed to each job and is used to move the job throughout the wafer fab after job formation.
Proceedings of the Winter Simulation Conference, 2002
... 159-163. Chance, F. 1996. Factory Explorer® users' guide. Hopp, WJ and ML Spearman. 1996... more ... 159-163. Chance, F. 1996. Factory Explorer® users' guide. Hopp, WJ and ML Spearman. 1996.Factory physics; foundation of manufacturing management. Chicago: Irwin. Sze, SM 1985. Semiconductor Devices: Physics and Technology. New York: John Wiley & Sons. ...
ABSTRACT We investigate the integrated production and distribution scheduling problem in a supply... more ABSTRACT We investigate the integrated production and distribution scheduling problem in a supply chain. The manufacturer's production environment is modeled as a parallel machine system. A single capacitated vehicle is employed to deliver products in batches to multiple customers. The scheduling problem can also be viewed as either parallel machines with delivery considerations or a flexible flowshop. Different inventory holding costs, job sizes (volume or storage space required in the transportation unit), and job priorities are taken into account. Efficient mathematical modeling and near-optimal heuristic approaches are presented for minimizing total weighted completion time.
Transportation Research Part E: Logistics and Transportation Review, 2014
ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model... more ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model in which an interdictor chooses a limited amount of elements to attack first on a given network, and then an operator dispatches trains through the residual network. Our MIP model explicitly incorporates discrete unit flows of trains on the rail network with time-variant capacities. A real coal rail transportation network is used in order to generate scenarios to provide tactical and operational level vulnerability assessment analysis including rerouting decisions, travel and delay costs analysis, and the frequency of interdictions of facilities for the dynamic rail system.
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