• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.449-455
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• 2002

This paper considers that advanced planning and scheduling (APS) in manufacturing and the efficient purchasing where each customer order has its due date and multi-suppliers exit We present a Make-To­Order Supply Chan (MTOSC) model of efficient purchasing process from multi-suppliers and APS with outsourcing in a supply chain, which requires the absolute due date and minimized total cost. Our research has included two states. One is for efficient purchasing from suppliers: (a) selection of suppliers for required parts; (b) optimum part lead­time of selected suppliers. Supplier selection process has received considerable attention in the business­management literature. Determining suitable suppliers in the supply chain has become a key strategic consideration. However, the nature of these decisions usually is complex and unstructured. These influence factors can be divided into quantitative and qualitative factors. In the first level, linguistic values are used to assess the ratings for the qualitative factors such as profitability, relationship closeness and quality. In the second level a MTOSC model determines the solutions (supplier selection and order quantity) by considering quantitative factors such as part unit price, supplier's lead-time, and storage cost, etc. The other is for APS: (a) selection of the best machine for each operation; (b) deciding sequence of operations; (c) picking out the operations to be outsourcing; and (d) minimizing makespan under the due date of each customer's order. To solve the model, a genetic algorithm (GA)-based heuristic approach is developed. From the numerical experiments, GA­based approach could efficiently solve the proposed model, and show the best process plan and schedule for all customers' orders.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.57-66
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• 2010

In this paper, we propose the reliability constrained resource allocation scheduling algorithm in cellular network for uplink transmission, where uplink transmission is supported via packet switching schemes without the dedicated uplink circuit links. We evaluate the performance of the proposed algorithm, and compared with the conventional works to identify the pros and cons. The proposed uplink scheduling algorithm is to satisfy the constraints requirements of the MTC services which is considered as the core technology for future mobile wireless networks. It is different to conventional works which target to maximize the link capacity. The proposed algorithm provides reliable uplink transmission independent to the location and the quality of the wireless link of the mobile terminal. Based on the performance evaluation results, we conclude that the proposed method provides enhanced reliability performance than conventional works.

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.1-11
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• 2010

K company produces semiconductor package products under the make-to-order policy to supply for domestic and foreign semiconductor manufacturing companies. Its production process is a machine-paced assembly line type, which consists of die sawing, assembly, and test. This paper suggests three plans to increase process throughput based on the process analysis of K company and evaluates them via a simulation model using a real data collected. The three plans are line balancing by adding machines to the bottleneck process, product group scheduling, and reallocation of the operators in non-bottleneck processes. The evaluation result shows the highest daily throughput increase of 17.3% with an effect of 2.8% reduction of due date violation when the three plans are applied together. Payback period for the mixed application of the three plans is obtained as 1.37 years.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.4
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• pp.159-168
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• 2012

The purpose of this study is to analyze the relationship of MOT and NPD performance in medium-sized manufacturing firms. To accomplish the purpose of the study, working hypotheses were established based on the literatures about the impacts of MOT factors on the NPD performance. The sample of this study is as follows : 12 electrical and electronics companies, 18 machine and engineering companies, 16 parts and materials companies. In order to verify hypotheses, the data were collected from team leader and manager of research center, R&D, and production department of these companies and the leader of R&D project team who all had experience in project or were participating in it in latest 3 years. The results of study were summarized as follows : First, in analysis on the reality of MOT factors in sample firms, will of top management level on the MOT was comparatively high but relatedness of business strategy and technology strategy, open R&D system, systematic time scheduling, management of R&D manpower, and developing and adapting PLM system were common level. Second, to improve NPD performance in medium-sized manufacturing firms, will of top management level on the MOT, relatedness of business strategy and technology strategy, open R&D system, systematic time scheduling, management of R&D manpower, and developing and adapting PLM system were intensively required.

• Industrial Engineering and Management Systems
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• v.12 no.1
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• pp.51-62
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• 2013

This paper considers a single machine rescheduling problem whose original (efficiency related) objective is minimizing makespan. We assume that disruptions such as order cancelations and newly arrived orders occur after the initial scheduling, and we reschedule this disrupted schedule with the objective of minimizing a disruption related objective while preserving the original objective. The disruption related objective measures the impact of the disruptions as difference of completion times in the remaining (uncanceled) jobs before and after the disruptions. The artificial due dates for the remaining jobs are set to completion times in the original schedule while newly arrived jobs do not have due dates. Then, the objective of the rescheduling is minimizing the maximum earliness without tardiness. In order to preserve the optimality of the original objective, we assume that no-idle time and no tardiness are allowed while rescheduling. We first define this new problem and prove that the general version of the problem is unary NP-complete. Then, we develop three simple but intuitive heuristics. For each of the three heuristics, we find a tight bound on the measure called modified z-approximation ratio. The best theoretical bound is found to be 0.5 - ${\varepsilon}$ for some ${\varepsilon}$ > 0, and it implies that the solution value of the best heuristic is at most around a half of the worst possible solution value. Finally, we empirically evaluate the heuristics and demonstrate that the two best heuristics perform much better than the other one.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.74-79
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• 2009

This paper proposes a hardware structure and associated finite state machine designs sharing key scheduling circuitry to enhance the performance of the block cypher algorithm, HIGHT. It also introduces an efficient protocol applicable to RFID systems comprising the HIGHT block cipher algorithm. The new HIGHT structure occupies an area size small enough to accommodate tag applications. The structure yields twice higher performance them conventional HIGHT algorithms. The proposed protocol overcomes the security vulnerability of RFID tags and thereby strengthens the security of personal information.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12C
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• pp.218-224
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• 2001

The objective of Distributed Parallel Computing is to solve the computationally intensive problems, which have several types of parallelism, on a suite of high performance and parallel machines in a manner that best utilizes the capabilities of each machine. In this paper, we propose a computational model including the generalized graph representation method of distributed parallel systems for speedup analysis, and analyze how the super-linear speedup is achieved when scheduling of programs with diverse embedded parallelism modes onto a distributed heterogeneous supercomputing network environment. The proposed representation method can also be applied to simple homogeneous or heterogeneous systems whose components are heterogeneous only in terms of the processor speed. In order to obtain the core speedup, the matching of the parallelism characteristics between tasks and parallel machines should be carefully handled while minimizing the communication overhead.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.31-40
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• 2005

In this study, we study measurement of wafer processing throughput and sequence simulation of single wafer type for wafer cleaning equipments that were used for etching, cleaning and polishing of wafer. Based on finite state machine, simulation model was built with identification of robot's status according to scheduling algorithm. Moreover, through performance of simulation as above, throughput per hour of cleaning equipment was measured. By the simulation method that are proposed in this paper, we could measure the wafer throughput per hour according to recipe and robot motion speed, and find optimal recipe and moving sequence of robot that maximize the throughput.

• IE interfaces
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• v.19 no.2
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• pp.124-132
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• 2006

The system under study is a single item, multi-echelon distribution system with a capacitated production facility. All the nodes at the downstream ends are demand-sites, i.e., ordered items are delivered to the customers from the node. Also any transshipment depots in the midstream can be demand-sites as well. For a given planning period, at each of demand-site, demand is forecasted and known. Our objective is to minimize the average system cost per period which is the sum of holding and backorder costs in the entire network. Due to the capacity restrictions, it is difficult to establish efficient distribution planning. To overcome such a difficulty and obtain a reasonable and better solution, we convert this problem into a single machine earliness and weighted tardiness scheduling. We propose a simple but cost-effective heuristic for this problem. The experimental results showed that the proposed heuristic obtained much better solutions compared with another approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1838-1855
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• 2008

The manufacturing industry seeks for improvements in efficiency at the manufacturing process. This paper presents a method for effective real time dispatching for parallel machines with multi product that minimizes mean tardiness and maximizes the quality of the product. What is shown in this paper is that using the Rolling Horizon Tabu search method in the real time dispatching process, mean tardiness can be reduced to the minimum. The effectiveness of the method presented in this paper has been examined in the simulation and compared with other dispatching methods. In fact, using this method manufacturing companies can increase profits and improve customer satisfaction as well.