• Safety and Health at Work
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• 제9권1호
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• pp.42-52
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• 2018

Background: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high man-machine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personnel. An effective human error probability model is required to better manage maintenance on-board ships. The developed model would assist in developing and maintaining effective risk management protocols. Thus, the objective of this study is to develop a human error probability model considering various internal and external factors affecting seafarers' performance. Methods: The human error probability model is developed using probability theory applied to Bayesian network. The model is tested using the data received through the developed questionnaire survey of >200 experienced seafarers with >5 years of experience. The model developed in this study is used to find out the reliability of human performance on particular maintenance activities. Results: The developed methodology is tested on the maintenance of marine engine's cooling water pump for engine department and anchor windlass for deck department. In the considered case studies, human error probabilities are estimated in various scenarios and the results are compared between the scenarios and the different seafarer categories. The results of the case studies for both departments are also compared. Conclusion: The developed model is effective in assessing human error probabilities. These probabilities would get dynamically updated as and when new information is available on changes in either internal (i.e., training, experience, and fatigue) or external (i.e., environmental and operational conditions such as weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress) factors.

• 정보보호학회논문지
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• 제22권2호
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• pp.213-224
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• 2012

통합된 코어 망 구조(core network architecture)와 다양한 무선 가입자 행동들은 3GPP in Release 8에서 제안된 EPC(Evolved Packet Core Network)에서 상당한 시그널링 부하 증가를 가져온다. 따라서 인증 시그널링 분석(authentication signaling analysis)은 체감품질(quality-of-experience)을 충족시키면서 인증 시그널링 부하와 지연을 줄이는 통찰력을 갖게 해준다. 본 논문에서는 갱신 과정 이론(renewal process theory)에 기반을 둔 분석적 모델링을 통해 EPS 구조에서의 시그널링 부하에 대해 평가하였다. 갱신 과정 이론은 특정 랜덤 과정(random process)에 상관없이 잘 작동 한다 (예. 포아송(Poisson)). 본 논문은 발신 발생 속도(call arrival rate), 이동성(mobility), 가입자들의 선호도와 운영정책의 관점에서 가입자들의 다양한 패턴을 고려하였다. 매개변수들과 성능지표들 사이의 상호관계를 나타내기 위해 수치적인 결과를 사용하였다. 수직적 핸드오버(vertical handover) 성능의 민감도와 heavy-tail process의 영향에 대해서도 검토하였다.

• 항공우주시스템공학회지
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• 제13권6호
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• pp.36-42
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• 2019

본 논문은 유/무인 항공기 복합운용체계 검증을 위한 시뮬레이션 환경 구축 및 통합 시험에 대하여 다룬다. 유/무인 항공기 지상 시뮬레이션 환경 구축을 위해서 유인기용 시뮬레이터인 X-Plane과 무인기용 시뮬레이터 HILS를 연동하여 상호 복합운영이 가능한지 시뮬레이션으로 검증하였다. 실제 비행시험 전 유/무인 항공기 및 지상통제실 간 C Band 및 UHF 채널을 이용한 통신 가능성을 확인하기 위하여 통신장비를 제작하고 유인 항공기를 이용한 검증을 수행하였다.

• 한국정보시스템학회지:정보시스템연구
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• 제24권2호
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• pp.163-188
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• 2015

Purpose The healthcare services have drawn so much public attention, and many organizations such as schools and companies require the individuals to undergo the periodic health examination. In general, however, the mass health examination services are not managed in systematic way, and both examinees and medical staffs often experience much inconvenience while preparing, undergoing and managing the services. To address such problems, this paper aims to design the Health Examination Management System (HEMS), an integrated management system for mass health examination operations management, and implement its prototype. Design/methodology/approach First of all, HEMS enables the medical staffs to efficiently collect and manage the examination result data by supporting examination service management. Second, the users can efficiently analyze the cause-and-effect relationships among the examination items by using the visualization tool of HEMS based on the cluster heat map. Finally, the HEMS provides the operational supports for evaluating and managing the service performances. Findings The HEMS indicates that the conventional operations management approaches can be incorporated into the mass health examination services, and it is expected that the proposed system enables the examinees and the medical staffs to participate in such services in more efficient way.

• 대한임베디드공학회논문지
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• 제12권5호
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• pp.331-341
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• 2017

This paper presents the sea-trial results of Crabster CR6000 which is a deep-sea walking robot developed by KRISO in 2016. Crabster CR6000 is designed to inspect deep-sea environment rejecting the disturbance on the silent and calm abyssal area. The sea-trial was conducted at the East Sea and the Philippine Sea on December 2016. The Crabster CR6000 undocked successfully from the Shuttle after touchdown on the sea-bed and walked out on the soft sediment soil of the 4,743m seafloor at the fourth diving in the Philippine Sea. The advanced technologies and capabilities of CR6000 were verified from the operational and functional test conducted in the sea-trial. The experimental data acquired from the sea-trial were summarized and the first experience of the deep-sea walking robot was presented in this paper.

• 경영정보학연구
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• 제8권1호
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• pp.223-239
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• 2006

디지털 경제 시대에 있어 정보시스템은 기업의 경쟁 우위 확보 차원을 넘어 생존의 차원에서 필요성을 인정 받고 있다. 기업은 신규 개발 또는 ERP 도입을 통해 정보시스템을 개발하고 이를 기반으로 사업을 추진하고 확장해야 하는 것이다. 그러나, 이러한 정보시스템의 성공적 운영에는 많은 현실적 문제가 있음을 인식해야 할 것이다. 특히, 중소기업의 경우 정보 시스템 운영 단계에서 많은 문제가 노출되어 운영에 차질이 생기거나 운영 자체를 포기하는 사례가 발생하고 있다. 본 논문은 중소기업의 성공적인 정보화 지속을 위해 효과적인 정보시스템 유지보수와 진화 관리를 위한 프레임웍을 제시하고자 한다. 사례 연구를 통해 설계된 프레임웍은 서비스 프레임웍, 감사 프레임웍, 위험관리 프레임웍 등으로 구성되어 있으며 중소기업의 정보화를 지속적으로 구현할 수 있는 정보시스템의 효과적인 운영 체제 구축에 활용될 수 있을 것으로 기대된다.

• 농촌지도와개발
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• 제8권2호
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• pp.209-221
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• 2001

The nature of work which is changing has increased the importance of HRD within organization. Also, these changes are making HRD shift its paradigm : from the segregated, closed, operational & administrative, dependent, utilitarian view to the integrative, open, strategic & facilitative, interdependent, generative view. The shifts of the perspective on HRD cause HRD professionals rethink the purpose and definition of HRD, and the role & competency needed to HRD in 21st century. The findings which are drawn through literature review and researcher’s intuition based on a long field experience are as follows. First, The function of HRD has recently been much more important then that of the past. Second, There is no consensus over the conceptual identity of HRD. Nonetheless, it is apparent that the preferred activities of the HRD function is performance improvement. Third, It is too difficult that we should define clearly the role & competency of HRD because of diverse perspectives on them. But we find much evidence converging to support the fact that the role & competency of HRD should be extended from the sole focus on training & development to adding the additional role & competency of change agent, who includes planning, implementing, and managing change.

• 전기학회논문지
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• 제67권5호
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• pp.680-687
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• 2018

Because of its predictability of the energy cycle and huge scale power output, the ocean energy from tidal power utilization has always received attention as a great energy source, even though its development cost, including the embankment construction, is so much higher than that of any other energy source. Nevertheless, nowadays many projects are being planned on account of institutional support from the government and the recent advance of construction technology. In Korea, the new industry field operating and managing the tidal power plant has already opened. But we are facing a number of problems for optimal operation of tidal power plant that are a lack of operation experience and a skill of professional management and others. This paper suggests a novel way to determine the starting head of power generation by generating power comparison method For this new method, the paper discusses many factors including changing the volume of the basin, the number of operating turbines and gates and forecasting the tidal amplitude and the characteristic curve of turbine and gate. Finally we verified that it can increase about 2% an annual power generation compared with the conventional method using the original operational function made in the plant design process.

• 한국경영과학회지
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• 제23권2호
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• pp.187-200
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• 1998

This paper presents an original approach for solving short-term power scheduling in extended power system with two fuels in a unit and a limited fuel using Lagrangian relaxations. The underlying model incorporates the full set of costs and constraints including setup, production, ramping, and operational status, and takes the form of a mixed integer nonlinear control problem. Moreover, the mathematical model developed includes two fuels in a unit and a limited fuel, regulation reserve requirements of prespecified group of units. Lagrangian relaxation is used to disaggregate the model by generator into separate subproblems which are then solved with a nested dynamic program including empirical knowledges. The strength of the methodology lies partially in its ability to construct good feasible solutions from information provided by the dual. Thus, the need for branch-and-bound is eliminated. In addition, the inclusion of two fuels in a unit and a limited fuel provides new insight into the limitations of current techniques. Computational experience with the proposed algorithm indicates that Problems containing up to 23 units including 8 unit used two fuels and 24 time periods can be readily solved in reasonable times. Duality gaps of less than 4％ were achieved.

• 산업공학
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• 제18권1호
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• pp.73-81
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• 2005

Injection molding has been widely used in producing plastic parts in large quantities. However, its productivity mainly depends on the expertise and experience of skilled workers because of the difficulty and complexity to determine a robust injection molding condition which is not influenced by the minor operational variation of an injection molding machine and produces good parts continuously. This study analyzes the defect types of the parts and proposes a support system to assist users in determining the robust process condition. The support system calculates the start condition from the information of an injection mold, the injection molding machine, the resin used, and the part. Through the iterative step which updates the condition using the defect information of the part tested, users can obtain the initial condition which produces the part without any problem for the first time. The support system also assists users in obtaining the robust condition from the initial condition using the technique of experimental design. To prove the validity of the support system, this study implements it in the control panel of the injection molding machine.