• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.141-148
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• 1992

본 사례연구는 자동차용 스프링 제조업체의 생산합리화를 위하여 공정별 생산능력을 고려한 작업량 할당방안에 관한 것이다. 현재 자동차용 스프링 제조업체의 전 생산공정은 크게 압연공정, 열간작업공정, 열처리.조립공정으로 구성되어있다. 열처리.조립공정에 대해서는 열간작업을 마친 작업물을 일정한 투입순서에 의하여 투입만 통제하면 된다. 또한 압연공정도 별도로 관리되고 있는것이 스프링 제조업체의 현실이다. 따라서 열간작업에서의 작업량 할당이 결국은 스프링 제조업체의 생산계획에 있어서 제일 중요한 문제이므로 열간작업에 대한 합리적인 작업량 할당이 이루어져야 한다. 따라서 본 사례연구에서는 각 공정에 대한 공정능력 및 불량률을 분석하여 각 공정의 기간별 부하량을 평준화 시킬 수 있는 주별, 일별 작업량 할당방안을 제시한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.253-256
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• 2000

In general, Automated Storage/Retrieval Systems (AS/RS ) have racks of equal sized cells to utilize the concept of unit-load. Most of the techniques for the performance estimation of a unit-load AS/RS are a static model or computer simulation. Especially, their models were developed under assumption that the Storage/Retrieval (S/R) machine performs only single command (SC) or dual command (DC). In reality, defending on the operating policy and the status of the system at a particular time, the S/B machine performs a SC or a DC, or becomes .: idle. In order to resolve these weak points, we propose a stochastic model for the performance estimation of unit-load AS/RS by using a single-server queueing model. Expected numbers of waiting storage and retrieval commands are found

• Journal of the Korean Society of Food Culture
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• v.1 no.3
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• pp.279-294
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• 1986

In order to survey the traditional salt production at the eastern coast, Young-Hae, in Yi-dynasty, data of salt production were collected through interviewing with whom had received the skill from ancestors and analyzed the data. The results obtained were as follows. Salt-producer take the salt water containing much salt and then he transported the salt-water by having water buckets an back in with using the water-toting device (Mul ji ge). Finally he carried out the irrigation (Mul dae gi) to a ditch (Dorang). It is noteworthy that the East-sea salt production method was not selecting a method of salt-pond style with a bank for salt production but using the salt water transportation fashion without a bank for that. Judging from these facts, we could conclude that traditional salt production method was handed down into the Yi-dynasty from ancient times.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.1
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• pp.54-60
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• 2001

In this paper, a shape-based block layout (SBL) approach is presented to solve the facility layout problem with unequal-area and fixed shapes. The SBL approach employs hybrid genetic algorithm (Hybrid-GA) to find a good solution and the concept of bay structure is used. In the typical facility layout problem with unequal area and fixed shapes, the given geometric constraints of unequal-area and fixed shapes are mostly approximated to original shape by aspect ratio. Thus, the layout results require extensive manual revision to create practical layouts and it produces irregular building shapes and too much unusable spaces. Experimental results show that a SBL model is able to produce better solution and to create more practical layouts than those of existing approaches.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.4
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• pp.91-112
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• 2009

The bullwhip effect means the phenomenon of increasing demand variation as moving UP to the upstream in the supply chain. Therefore, it is recognized that the bullwhip effect is problematic for effective supply chain operations. In this paper, we exactly quantifies the bullwhip effect for the case of stochastic lead time and seasonal demand in two-echelon supply chain where retailer employs a base-stock policy considering SARMA demand processes and stochastic lead time. We also investigate the behavior of the proposed measurement for the bullwhip effect with autoregressive and moving average coefficient, stochastic lead time, and seasonal factor.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.162-165
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• 1998

We consider a facility layout problem for optimized material flow system design in the automated production system design. Existing facility layout algorithm have a weak point that arranged facilities have irregular shape or don't preserve their own shape and size. The proposed algorithm give a layout which is minimize total material handling cost and maximize space utility under preserving each facilities' own shape and size.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.51-53
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• 2011

최근 우리나라는 해상 물동량 증가, 조선경기의 호황, 해양레저의 수요증가 등으로 인해 해상에서의 선박 교통량이 점점 증가 하고, 선박도 대형화가 되어가는 추세로서, 해상에서의 사고 개연성과 대형사고의 발생가능성이 높아지고 있다. 또한 허베이스피리트호의 사고에서 알 수 있듯이 연안에서 일어난 해양사고는 막대한 경제적 피해를 가져왔다. 따라서 본 연구에서는 영해를 포함한 EEZ해역에서의 선박통항량과 해양사고를 조사하여, 해상교통환경을 분석했다.

• Journal of the Korea Society for Simulation
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• v.4 no.2
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• pp.69-78
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• 1995

Simulation is generally used for the performance analysis and optimization of manufacturing systems. Therefore in this paper using the simulation techniques we obtain the information about the efficiency improvement and the optimization. Because simulation optimization method is subjected to the applied field and environment the general simulation optimization method does not exist. So we do not take the fixed optimization procedure but suggest the alternative one which is modified for applied field. This procedure supplies the optimized simulation information and helps improve the productivity of Geared-Motor assembly line. In order to optimize the manufacturing system we use two simulation languages, FACTOR/AIM and SLAMSYSTEM. The former gives the abundant output information. The latter gives the flexibility in simulation modeling.

• Journal of the Korea Society for Simulation
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• v.5 no.2
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• pp.85-93
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• 1996

Simulation is commonly used to find the best values of decision variables for problems which defy analytical solutions. This objective is similar to that of optimization problems and thus, mathematical programming techniques may be applied to simulation. However, the application of mathematical programming techniques, e.g., the gradient methods, to simulation is compounded by the random nature of simulation responses and by the complexity of the statistical issues involved. In this paper, therefore, we explain the Reverse-Simulation method to optimize a simulation model in a single simulation run. First, we point the problem of the previous Reverse-Simulation method. Secondly, we propose the new algorithm to solve the previous method and show the efficiency of the proposed algorithm.

• The Korea Journal of Herbology
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• v.21 no.4
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• pp.207-212
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• 2006

Objectives : This study was designed to investigate the effect of aromatherapy using rosemary on memory for college students. Methods : This study used equivalent control group pretest-posttest design. The subjects of this experiment consisted of thirty college students. Fifteen college students were in the experimental and control group each. As a treatment, intervention using rosemary aromatic candles was applied. Data was analyzed by SPSS Program. Results : List learning and verbal span were significantly improve in the experimental group (P=0.013, P=0.017, respectively). There was no significant difference between the two groups in others. Conclusion : These findings indicate that aromatherapy using rosemary could be effective in improving list learning and verbal span.