• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1124-1132
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• 2006

This paper considers a flow shop scheduling problem where a different WIP (work-in-process) state has different weight on the duration time. The objective is to minimize the sum of the weighted WIP. For the two machine flow shop case, the recognition version is unary NP-Complete. The three simple and intuitive heuristics H0, H1, and H2 are presented for the problem. For each heuristic, we find an upper bound on relative error which is tight in limit. For heuristic H2, we show that H2 dominates the other two heuristics.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.55-63
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• 2019

This paper develops an algorithm to determine the batch size of the batch process in real time for improving production and efficient control of production system with multiple processes and batch processes. It is so important to find the batch size of the batch process, because the variability arising from the batch process in the production system affects the capacity of the production. Specifically, batch size could change system efficiency such as throughput, WIP (Work In Process) in production system, batch formation time and so on. In order to improve the system variability and productivity, real time batch size determined by considering the preparation time and batch formation time according to the number of operation of the batch process. The purpose of the study is to control the WIP by applying CONWIP production system method in the production line and implements an algorithm for a real time batch size decision in a batch process that requires long work preparation time and affects system efficiency. In order to verify the efficiency of the developed algorithm that determine the batch size in a real time, an existed production system with fixed the batch size will be implemented first and determines that batch size in real time considering WIP in queue and average lead time in the current system. To comparing the efficiency of a system with a fixed batch size and a system that determines a batch size in real time, the results are analyzed using three evaluation indexes of lead time, throughput, and average WIP of the queue.

• IE interfaces
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• v.15 no.4
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• pp.349-355
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• 2002

In order to build a new factory, we must have answers regarding the following questions; 1. what is to be produced? 2. how are the products to be produced? 3. how much of each product will be produced? The answers are related to product-design, process-design and capacity-design respectively and they are used for layout-design as the input data. Especially capacity design decision provides the information regarding the number of equipments required and the balance of the line. This paper introduces a case study on the capacity design for a new factory where the retainers of ball bearing are manufactured. A simulation model is developed with ARENA for analyzing the system considered. The major objectives of the study are evaluating the performance of the line which is originally suggested by the company, and finding out alternatives for improving the system. Number of WIP between the processes are also investigated because it affects the space planning of the layout.

• Journal of the Korea Society for Simulation
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• v.26 no.1
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• pp.69-75
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• 2017

An MCP(Multi-chip Package) is a package consisting of several chips. Since several chips are stacked on the same substrate, multiple assembly steps are required to make an MCP. The characteristics of the chips in the MCP are dependent on the layer sequence. In the MCP manufacturing process, it is very essential to carefully consider the layer sequence in scheduling to achieve the intended throughput as well as the WIP balance. In this paper, we propose a scheduling methodology considering the layer sequence constraint.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.15.1-15.7
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• 2014

Objectives This paper tried to review a recent research trend for the environmental exposure of engineered nanomaterials (ENMs) and its removal efficiency in the nanowaste treatment plants. Methods The studies on the predicted environmental concentrations (PEC) of ENMs obtained by exposure modeling and treatment (or removal) efficiency in nanowaste treatment facilities, such as wastewater treatment plant (WTP) and waste incineration plant (WIP) were investigated. The studies on the landfill of nanowastes also were investigated. Results The Swiss Federal Laboratories for Materials Science and Technology group has led the way in developing methods for estimating ENM production and emissions. The PEC values are available for surface water, wastewater treatment plant effluents, biosolids, sediments, soils, and air. Based on the PEC modeling, the major routes for the environmental exposure of the ENMs were found as WTP effluents/sludge. The ENMs entered in the WTP were 90-99% removed and accumulated in the activated sludge and sludge cake. Additionally, the waste ash released from the WIP contain ENMs. Ultimately, landfills are the likely final destination of the disposed sludge or discarded ENMs products. Conclusions Although the removal efficiency of the ENMs using nanowaste treatment facilities is acceptable, the ENMs were accumulated on the sludge and then finally moved to the landfill. Therefore, the monitoring for the ENMs in the environment where the WTP effluent is discharged or biomass disposed is required to increase our knowledge on the fate and transport of the ENMs and to prevent the unintentional exposure (release) in the environment.

• Korean Management Science Review
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• v.17 no.1
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• pp.17-30
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• 2000

This paper addresses the effect of protective capacity on the lead time and throughput of a re-entrant line where statistical fluctuations exist in the form of variation in processing times and machine breakdowns. The specific framework employed in the paper is a five station re-entrant line structured as a closed network mode. This paper argues that protective capacity can be used in conjunction with WIP inventory in order to reduce the lead time and to increase the increase the throughput of a line. Simulation analyses are included to give insight into the effectiveness of protective capacity.

• Journal of Korean Institute of Industrial Engineers
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• v.15 no.1
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• pp.77-87
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• 1989

This paper deals with an automated storage carrousel which handles work-in-process(WIP) such as small parts for kitting. The system has been used predominately for order picking applications. Throughput performance of the system can be measured by the inverse of the expected order picking time. Analytic models are developed for approximating the expected times under the "nearest-item" sequencing rule. The performance of the models are tested through computer simulation. The gap between the two is shown to be reasonably small.

• Journal of Integrative Natural Science
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• v.9 no.1
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• pp.35-40
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• 2016

Protein phosphatase manganese dependent 1D (PPM1D) is one of the Ser/Thr protein phosphatases belongs to the PP2C family. They play an important role in cancer tumorigenesis of various tumors including neuroblastoma, pancreatic adenocarcinoma, medulloblastoma, breast cancer, prostate cancer and ovarian cancer. Even though PPM1D is involved in the pathophysiology of various tumors, the three dimensional protein structure is still unknown. Hence in the present study, homology modelling of PPM1D was performed. 20 different models were modelled using single- and multiple-template based homology modelling and validated using different techniques. Best models were selected based on the validation. Three models were selected and found to have similar structures. The predicted models may be useful as a tool in studying the pathophysiological role of PPM1D.

• Journal of Life Science
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• v.19 no.1
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• pp.1-8
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• 2009

In this paper, to elucidate the further mechanisms of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced growth arrest, we investigated the effect of MNNG on cell cycle and proliferation in U937 cells, a p53-null human myeloid leukemia cell line. It was found that MNNG causes an arrest at the G2/M phase of the cell cycle and induces apoptosis, which is closely correlated to inhibition of cyclin B1 and cyelin-dependent kinase (Cdk) 2-associated kinase activities. MNNG treatment in. creased protein and mRNA levels of the Cdk inhibitor p21(WAF1/CIP1), and activated the reporter construct of a p21 promoter. By using p21 promoter deletion constructs, the MNNG-responsive element was mapped to a region between 113 and 61 relative to the transcription start site. These data indicate that in U937 cells MNNG can circumvent the loss of wild-type p53 function and induce critical downstream regulatory events leading to transcriptional activation of p21. Present results indicate that the p53-independent up-regulation of p21 by MNNG is likely responsible for the inhibition of cyclin/Cdk complex kinase activity rather than the down-regulation of cyclins and Cdks expression. These novel phenomena have not been previously described and provide important new insights into the possible biological effects of MNNG.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.83-86
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• 2006

모바일 플랫폼이 WIPI라는 표준 플랫폼으로 2004년 2월 WIP2.0으로 규격화되어 컨텐츠 개발 시간 및 비용의 최소화와 빠른 단말기 개발 공정으로 원활한 단말기 공급 그리고 1회의 컨텐츠 개발로 모든 이동 통신 사업자에 공급등 여러 가지 측면에서 장점을 가지게 되었다. 이러한 WIPI의 우수성을 우리가 직접 사용해 눈으로 확인 해보기 위해 모바일 컨텐츠 중에서 가장 활발하게 개발되고 있는 게임을 제작해 보았다.