Chang Sup Sung

Minimizing makespan on a single burn-in oven in semiconductor manufacturing

Abstract This paper considers a scheduling problem for a single burn-in oven in semiconductor manufacturing industry where the oven is a batch processing machine and each batch processing time is represented by the largest processing time among those of all the jobs contained in the batch. The objective measure of the problem is the maximum completion time (makespan) of all jobs. This paper investigates a static case in which all jobs are available to process at time zero, and also analyzes a dynamic case with different job-release times, for which a branch-and-bound algorithm and several heuristics are exploited. The worst case error performance ratios of the heuristics are also derived.

Integrated service network design for a cross-docking supply chain network

This paper considers an integrated service network design problem for a given set of freight demands that is concerned with integration of locating cross-docking (CD) centers and allocating vehicles for the associated direct (transportation) services from origin node to a CD center or from a CD center to the destination node. For the vehicle allocation, direct services (sub-routes) should be determined for the given freight demands, and then the vehicle allocation has to be made in consideration of routing for the associated direct service fulfillment subject to vehicle capacity and service time restriction. The problem is modeled as a path-based formulation for which a tabu-search-based solution algorithm is proposed. To guarantee the performance of the proposed solution algorithm, strong valid inequalities are derived based on the polyhedral characteristics of the problem domain and an efficient separation heuristic is derived for identifying any violated valid inequalities. Computational experiments are performed to test the performance of the proposed solution algorithm and also that of a valid-inequality separation algorithm, which finds that the solution algorithm works quite well and the separation algorithm provides strengthened lower bounds. Its immediate application may be made to strategic (integrated) service network designs and to tactical service network planning for the CD network.

Minimizing makespan in a two-machine flowshop with dynamic arrivals allowed

This paper considers a scheduling problem for a two-machine flowshop where a discrete processing machine is followed by a batch processing machine and a finite number of jobs arrive dynamically at the first machine. In the flowshop, the discrete processing machine processes one job at a time and the batch processing machine processes a batch of jobs simultaneously. The objective is to find the optimal schedule which minimizes the maximum completion time (makespan) of all jobs. In the situation where preemption is allowed on the discrete processing machine, it is shown that the optimal schedule can be found in polynomial time. However, in the situation where no preemption is allowed on the discrete processing machine, it is shown that the problem is NP-complete, for which an efficient heuristic solution algorithm is constructed and its tight worst-case error bound is derived. Numerical experiments show that the heuristic algorithm consistently generates good schedules.

Scheduling in a two-machine flowshop with batch processing machine(s) for earliness/tardiness measure under a common due date

Abstract This paper considers a scheduling problem for a two-machine flowshop with batch processing machine(s) (BPMs) incorporated where the earliness/tardiness (E/T) measure and a common due date are considered. It assumes that each batch has the same processing time and that the common due date is not set earlier than the total job processing time on the first machine. Under these assumptions, some solution properties are characterized for three different problem cases to derive their associated solution algorithms. For the first two cases concerned with two different machine sequences such as batch-to-discrete and batch-to-batch machine sequences, a polynomial time algorithm is derived based on some of the solution properties. For the last case concerned with discrete-to-batch machine sequence, a pseudopolynomial algorithm is exploited.

Minimizing makespan on a single burn-in oven with job families and dynamic job arrivals

This paper considers a scheduling problem for a single burn-in oven in the semiconductor manufacturing industry where the oven is a batch processing machine and each batch processing time is represented by the largest processing time among those of all the jobs contained in the batch. Each job belongs to one of the given number of families. Moreover, the release times of the jobs are different from one another. The objective measure of the problem is the maximum completion time (makespan) of all jobs. A dynamic programming algorithm is proposed in the order of polynomial time complexity for a situation where the number of job families is given (fixed). A computational experiment is performed to compare the time complexity of the proposed algorithm with that of another exact algorithm evaluating all possible job sequences based on batching-dynamic programming (BDP). The results of the experiment show that the proposed algorithm is superior to the other.

Minimizing due date related measures for a single machine scheduling problem with outsourcing allowed

This paper considers two single-machine scheduling problems with outsourcing allowed where each job can be either processed on an in-house single-machine or outsourced. They include the problem of minimizing maximum lateness and outsourcing costs, and that of minimizing total tardiness and outsourcing costs. Outsourcing is commonly required as a way to improve productivity in various companies including electronics industries and motor industries. The objective is to minimize the weighted sum of the outsourcing cost and the scheduling measure represented by either one of maximum lateness and total tardiness, subject to outsourcing budget. It is proved that the problem is NP-hard. Some solution properties are characterized to derive heuristic algorithms, and also a branch-and-bound algorithm. Numerical experiments are conducted to evaluate performance of the derived algorithms.

Dual-based approach for a hub network design problem under non-restrictive policy

Abstract This paper considers a hub network design problem where the network service area partitioned into the predetermined zones (represented by node clusters) is given, and non-stop (direct link) service is allowed. The objective is to design a hub network under non-restrictive networking policy by determining all the required hub locations in the predetermined zones and also all the terminal-to-terminal routes such that the total network cost (hub construction and flow transportation cost) is minimized. For the design problem, a dual-based solution approach is proposed and tested for its effectiveness with numerical examples.

An exact algorithm for a cross-docking supply chain network design problem

This paper proposes a branch-and-price algorithm as an exact algorithm for the cross-docking supply chain network design problem introduced by one of the authors of this paper. The objective is to optimally locate cross-docking (CD) centres and allocate vehicles for direct transportation services from the associated origin node to the associated CD centre or from the associated CD centre to the associated destination node so as to satisfy a given set of freight demands at minimum cost subject to the associated service (delivery) time restriction. A set-partitioning-based formulation is derived for the problem for which some solution properties are characterized. Based on the properties, a branch-and-price algorithm is derived. The properties can also be used in deriving any efficient local search heuristics with the move operation (neighbourhood search operation) of modifying assignment of some freight demands from current CD centres to other CD centres. Computational experiments show that the branch-and-price algorithm is effective and efficient and also that the solution properties contribute to improve the efficiency of the local search heuristics.

Minimizing due date related performance measures on two batch processing machines

Abstract This paper considers a scheduling problem in a two-machine flowshop of two batch processing machines. On each batch processing machine, jobs are processed in a batch, and each batch is allowed to contain jobs up to the maximum capacity of the associated machine. The scheduling problem is analyzed with respect to three due date related objectives including maximum tardiness, number of tardy jobs and total tardiness. In the analysis, several solution properties are characterized and based upon these properties, three efficient polynomial time algorithms are developed for minimizing the due date related measures.

Reliability optimization of a series system with multiple-choice and budget constraints

Abstract This paper considers a reliability optimization problem for a series system with multiple-choice constraints incorporated at each subsystem to maximize the system reliability subject to the system budget. The problem is formulated as a nonlinear binary integer programming problem and characterized as an NP-hard problem. In the problem analysis, some solution properties are characterized to reduce the solution space in advance. A branch-and-bound solution algorithm is then derived based on the reduced solution space to search for the optimal solution. The algorithm is tested for its efficiency with randomly generated numerical examples.