The Optimal Base-Stock Level in Assembly lines

고성석(Sung-Seok Ko),서동원(Dong-Won Seo) 한국산업경영시스템학회 2007 한국산업경영시스템학회지 Vol.30 No.3

  In this study, we consider an assembly line operated under a base-stock policy. A product consists of two parts, and a finished product transfers to a warehouse in which demands are satisfied. Assume that demands arrive according to a Poisson process and processing times at each production line are exponentially distributed. Whenever a demand arrives, it is satisfied immediately from an inventory in the warehouse if available; otherwise, it is backlogged and satisfied later by the next product exiting from production lines. In either case, an arriving demand automatically triggers the production of a part at both production lines. These two parts will be assembled into a product that eventually transfers to the warehouse. We obtain a closed form formula of approximation for delay time or lead time distribution of a demand when a base- stock level is s. Moreover, it can be applied to the optimal base-stock level which minimizes the total inventory cost. Numerical examples are presented to show our optimal base-stock level"s quality.

옵션 계약을 통한 공급사슬내 공급자-판매자간 협력 문제

고성석(Sung-Seok Ko),한용희(Yong-Hee Han) 한국산업경영시스템학회 2012 한국산업경영시스템학회지 Vol.35 No.2

공급사슬상에서의 구성원간 협력이 보편화되어가는 현재의 추세에 따라 본 논문은 공급자-판매자로 구성된 공급 사슬에서의 옵션 계약을 통한 구성원간 협력 문제에 대해 연구하였다. 구체적으로, 본 논문은 가격이 공급자에 의해 결정되고 옵션 계약 물량이 판매자에 의해 결정될 경우에 대한 공급사슬 전체 관점 및 각 구성원 관점에서의 최적 옵션 가격, (옵션) 행사 가격, 현물 시장 가격, 옵션 계약 물량 결정 문제를 계량적으로 연구하였다. 본 논문의 연구결과를 통해 옵션 계약이 공급사슬에서의 구성원간 협력에 이용되는 경우에 대한 좀 더 나은 이해가 가능하며, 본 논문에서 제시한 예제는 실제 공급사슬상에서의 최종 소비자 수요가 정규분포나 연속균등분포등의 특정 분포를 따를 경우에 대한 최적 가격 및 옵션 계약 물량 계산 방법을 설명한다.

온라인 협업 시스템의 품질 관리 체계에 대한 연구

고성석(Sung-Seok Ko),조미연(Miyeon Cho) 한국산업경영시스템학회 2010 한국산업경영시스템학회지 Vol.33 No.2

Recently, the illlportance of quality con trol on the online co llabora tion system is increasing, since it is realized that many parti cipants do not guarantee the quality of online collaboration’ s Oll tpu t anylllore. Hence in this paper, we propose the frame work of qu ality control in order to ass ure the qllality of Olltput frolll online co ll abo ration systelll. The proposed framework prov ides the solution strategies to overcome the challenges of cu rrent co llaboration systems. To do that, fi rst of all we define the basic process (create, ini tiate, discuss, complete) of th e onli ne co llaboration system based on wiki -based system or open source project, and then we fi nd the challenges in each online co llaboration process, and propose the effective strategy to overcome these challenges with reference cases inc llld ing W ikipedi a, OSS project, etc.

중소 요식업체의 소셜커머스 활용 전략에 관한 연구

고성석(Sung-Seok Ko),김민규(Min-Gyu Kim),유영진(Young-Jin Yoo),김석술(Seok-Sul Kim) 한국산업경영시스템학회 2012 한국산업경영시스템학회지 Vol.35 No.1

Recently, Social Commerce that provides customer with cheap deals is under the spotlight. The purpose of this study is to propose how to use social commerce on small restaurant business, which encompass almost a half of entire deals. We analyzed each element from the last transaction data of three social commerce company and survey obtained from the restaurant business. As a result, we can find that the purpose of promoting, the location of restaurant, whether is franchise or not, price and menu composition have an effect on sales of coupon. Based on these results, we proposed two step approaches to use the social commerce company. The first step is to decide whether social commerce is used or not and the second step is to define the detail content of deal including the social commerce company. We convinced that our proposed strategy is very helpful to the small restaurant which considers utilization of social commerce company.

보강형의 시공방법을 고려한 타정식 현수교의 초기형상해석 모델

고성석(Ko Seong Seok),강성후(Kang Sung Hoo),박선준(Park Sun Joon),정재호(Jung Jae Ho) 대한토목학회 2009 대한토목학회논문집 A Vol.29 No.4A

타정식 현수교의 보강형 가설중의 경계조건과 하중조건의 변화를 고려하여 초기형상을 결정하기 위한 구조해석 모델링 방법 및 해석 알고리즘을 제안하였다. 타정식 현수교의 가설단계를 보강형의 가설시점을 기준으로 보강형 가설단계인 1단계와 완공단계의 2단계로 구분하였으며 이러한 가설단계를 고려하여 초기형상해석 단계를 1차 형상해석과 2차 형상보정해석의 2단계로 구분하였다. 각 해석단계에 대한 보강형의 경계조건과 작용하중의 모델링 방법 및 반복해석 알고리즘을 제안하였으며 실 교량에 대해 수치해석을 수행하여 기존 해석방법에 의한 초기형상해석결과와 비교, 분석하였다. 실 교량에 대한 수치해석결과 기존 초기형상해석방법의 문제점을 파악할 수 있었으며 본 연구에서 제안된 방법을 적용할 경우 기존 방법의 문제점을 해결할 수 있음을 확인하였다. To determine the initial configuration of the suspension bridge appropriate idealization model and analysis procedure are proposed as considering the boundary and loading conditions of stiffening girder during the erection. The construction stages of a suspension bridge are divided into two steps which are the first stage of the erection and the second stage of the completion in terms of the erection time of stiffening girders, and depending upon such an erection step the initial configuration analysis is classified the first configuration analysis and the revision analysis of the second configuration. The boundary and loading conditions and the analysis procedures for each stage are suggested and the results are verified by comparing with existing data. The results show that the proposed method provides better solution compared to the results using existing method.

동물식별 개체이력정보 추적을 위한 RFID 검색 시스템 구현에 관한 연구

백민호(Min-Ho Park),고성석(Sung-Seok Ko) 한국산업경영시스템학회 2008 한국산업경영시스템학회지 Vol.31 No.1

  Food and Agriculture Organization (FAO) and many countries make an effort to conserve and utilization of animal genetic resources to prepare for our unpredictable future. In order to protect the customer and the producer from the animal diseases and unjust distribution, many country seek to appropriate solution. Among the solutions, RFID technology can be used as a basic technology, since this technology can be applied in the conservancy and utilization of animal genetic resources, object management for improved animal and traceability of animal"s distribution flow.<BR>  There are two main issues in making the efficient RFID environment. The first issue is the standardization of code system for object identification. International Organization for Standard (ISO) published the standard which regulates RFID of animal (ISO 11784 and ISO 11785). Based on these standards, many countries have tried to establish their national standard. In Korea, National Institute of Animal Science (NIAS) play a main role in establishing the standard of object identification code based on ISO 11784. Even though the standard format of object"s identification is well established, the RFID system may not be operated well without the standardization of RFID network and related equipment. In Korea, National Internet Development Agency of Korea (NIDA) has proposed the RFID Network at 2006, which can be applied in the different kind of system at each phase. But, the implementation case of this RFID Network does not reported yet, since many company or agency who introduce RFID technology, implemented as an isolated individual system. In our study, we show that RFID network can be utilized for any kind of system at each phase, and propose the improvement point in order to be widely used.

통계적 기법을 이용한 집단 협업 프로젝트에서의 공정한 동료 평가 방법론에 대한 연구

조미연(Miyeon Cho),고성석(Sung-Seok Ko) 한국산업경영시스템학회 2013 한국산업경영시스템학회지 Vol.36 No.1

For evaluating participation in collaboration project, the peer assement method is mostly used and various scoring methods have been proposed. But, the reliability and validity of the peer assessment method are still doubted for all most method. In order to overcome these weaknesss, some guidelines and training methods have been recommended. In this article, however, statistical technique is proposed for measuring individual contributions to collaboration projects considering each assessor's reliability. The gist of our proposed algorithm is that an assessor's reliability depends on the evaluation policy, and this reliability is evaluated by an analysis of variance of the scores assigned by the assessor. We also show that the proposed method is very efficient by case study in university class.

농축산물 생산 이력 정보 추적을 위한 RFID 코드체계에 관한 연구

백민호(Paek Min Ho),고성석(Ko Sung-Seok) 한국전자거래학회 2007 한국전자거래학회지 Vol.12 No.2

농축산물 산업은 복잡한 유통 구조를 보이고 있고, 농축산물에 대한 안전성에 대한 소비자의 요구가 높아지고 있다. 이에 대한 대응방안으로 생산 이력에 대한 정확한 정보 제공과 활용을 제공할 수 있는 RFID 기반 정보 시스템의 구축 벚 계획 중에 있다. 그러나 개별 사업주체들에 의해 사업이 추진되고 있고 코드 체계가 확립되지 않아 상호간 정보 교류가 쉽지 않을 뿐 아니라, 사업의 고도화 빛 확산에 많은 어려움을 껶고 있다. 이러한 문제를 극복하고 RFID 시스템의 장점을 극대화시키기 위해 글로벌 네트워크 표준과 국가 RFID 표준 체계에 근거한 RFID 기반 농축산물 생산 이력정보 검색을 위한 RFID 코드 체계를 제안하고자 한다. The agro-livestock industry is composed of a complicated supply chain and the customer's interest in safety of agro-livestock products is increasing. In order to provide customer with the accurate information about the history of product, and make good use of these information, traceability systems based on RFID technology were implemented and are planned. It is, however, difficult to make the efficient flow of information and to enhance or expand the traceability system because of the lack of the standard of RFID code system. To overcome this problem, we propose a RFID code system for the traceability of argo-livestock products on the basis of ISO/IEC 15459 KKR code system.

Newsvendor Problem with Downside-risk Constraint under Unreliable Supplier

김형태(Hyoung-Tae Kim),고성석(Sung-Seok Ko),김주철(Joo-Cheol Kim) 한국산업경영시스템학회 2007 한국산업경영시스템학회지 Vol.30 No.2

  이 논문의 공급업체의 불확실성하에서의 신문팔이 문제를 다루고 있다. 즉 공급업체의 공급량이 소매업체가 주문한 양을 충족하기 못하는 상황을 고려한 것이다. 여기서 우리는 기대 이익을 최대화하는 최적의 주문량을 구하였고, 기존의 연구와 달리 소매업체의 위험 성향을 고려하기 위해 하향 리스크에 대한 제약 조건을 추가하여, 위험 성향이 높을수록 더 많은 주문량을 사용한다는 결과를 사례 연구를 통해 확인할 수 있었다.

The Impact of ISO 13485 on the Performance of Korean Medical Device Manufacturers

Chung-Yeon Kim(김충연),Sung-Seok Ko(고성석),Yong-Hee Han(한용희) 한국산업경영시스템학회 2018 한국산업경영시스템학회지 Vol.41 No.1

This paper investigated relationship among internal as well as external motive to receive the ISO 13485 certification, counter-measure to the certification examination, active reception/execution level of the certification, and operational as well as financial performance of the medical device related enterprises in South Korea which received and are maintaining the ISO 13485 certification. SEM (structural equation model) and related analyses using AMOS 21.0 and SPSS 21.0 have been applied to verify the hypotheses of the research. Result of the research showed that internal as well as external motive for certification positively(+) affects active reception/execution level of the certification as well as countermeasure to the certification examination. The reception/execution level of the certification also positively(+) affects on the operational as well as financial performance of the certified enterprises. However, countermeasure to the certification examination was found out to negatively(-) affects the active reception/execution level of the certification and we can interpret that relatively more countermeasure to the certification examination burdens the employees of the enterprise, causing them to be less active on the reception/execution level of the certification. This research found that an enterprise’s operational/financial performance improves when an enterprise introduces the ISO 13485 certification standard spontaneously on the purpose of improving its system and the certification system is applied to the enterprise actively, not passively. This research emphasizes the need to recognize the difference of the level of active reception implication among members of an enterprise according to the motive of introduction of the certification system.