• Asia pacific journal of information systems
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• 제10권1호
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• pp.61-79
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• 2000

ERP system is a very popular tool for pushing management innovation and implementing an integrated information system. The purpose of this research is to investigate the relationship among the structure of production systems, types of implementation strategy, relative importance of competitive goals, information technology and culture level, and the efficiency from using the system. The data for this study were collected from 45 Korean manufacturing firms that have implemented ERP system. Research results confirm that the success factors include the top managements' strategic views and culture level related to new information technology. But the linkage between the structure of production systems and types of implementation strategy is proved to be very weak. Also control effect of types of implementation strategy on the efficiency of the organization is not strongly recognized. A summarized report of other findings is provided as well.

• Structural Engineering and Mechanics
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• 제38권1호
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• pp.39-63
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• 2011

Referring to the formulation of physical stochastic optimal control of structures and the scheme of optimal polynomial control, a nonlinear stochastic optimal control strategy is developed for a class of structural systems with hysteretic behaviors in the present paper. This control strategy provides an amenable approach to the classical stochastic optimal control strategies, bypasses the dilemma involved in It$\hat{o}$-type stochastic differential equations and is applicable to the dynamical systems driven by practical non-stationary and non-white random excitations, such as earthquake ground motions, strong winds and sea waves. The newly developed generalized optimal control policy is integrated in the nonlinear stochastic optimal control scheme so as to logically distribute the controllers and design their parameters associated with control gains. For illustrative purposes, the stochastic optimal controls of two base-excited multi-degree-of-freedom structural systems with hysteretic behavior in Clough bilinear model and Bouc-Wen differential model, respectively, are investigated. Numerical results reveal that a linear control with the 1st-order controller suffices even for the hysteretic structural systems when a control criterion in exceedance probability performance function for designing the weighting matrices is employed. This is practically meaningful due to the nonlinear controllers which may be associated with dynamical instabilities being saved. It is also noted that using the generalized optimal control policy, the maximum control effectiveness with the few number of control devices can be achieved, allowing for a desirable structural performance. It is remarked, meanwhile, that the response process and energy-dissipation behavior of the hysteretic structures are controlled to a certain extent.

• 로봇학회논문지
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• 제15권4호
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• pp.330-340
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• 2020

The purpose of this study was to develop Dementia-Care-Robot integrated program based on group customization and to identify effects on IADL, depression, and attitudes toward robot. This study was nonequivalent control group pre-post test design. The subjects were 40 elders diagnosed with mild dementia participating in the dementia center daily program (20 in the experimental group and 20 in the control group). Each session lasted for 30 minutes, twice a week during 6 weeks. Data were collected from July 16 to November 7, 2019, and were analyzed using SPSS WIN 22.0 program to identify differences between groups for variables. After the program, the experimental group improved in IADL, depression, but there were no significant differences between the two groups. In attitude toward robot, the experimental group showed positive change to the robot, but the control group showed negative change to it, also there was a significant difference between the two groups. Findings indicate that integrated program using Dementia-Care-Robot has potential as a strategy to improve the symptoms of dementia and to delay the progression. It needs to be applied in the medical field through convergent approach of engineering.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.75.1-75.1
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• 2010

This research presents a fuel cell simulator for control logic verification and operator training. Nowadays, power industries are focusing on clean energy as a response to new policy. The fuel cell can be the solution for clean energy, but operating technology is not well developed compared to other conventional power plans because of its short history. Therefore we need a simulator to verify the new control strategy and train operators, because the price of a real fuel cell system is too high and mechanically weak to be used for these kind of purposes. To develop the simulator, a 300 KW MCFC(Molten Carbonate Fuel Cell) system was modeled with stack, BOPs(pre-reformer, steam generator, etc) and mechanical components(valves, pipes, pumps, blowers, etc). The process model was integrated to emulated control system and HMI(Human Machine Interface). A static load and open loop tests were conducted for verifying the accuracy of the process model, since it is the most important part in the simulation. After verifying the process model, an automatic load change and start-up tests were conducted to verify the performance of a new control strategy(logic and functional loops).

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1232-1240
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• 2018

This paper aims at designing an intelligent controller, based on control Lyapunov Function strategy integrated with fabricating discrete model of Buck and Boost converters and analyzing energy changes during the DC/DC progress to realize tracing reference current on Buck and Boost converters. In addition, practical stability phenomenon research and transient performance analysis has been proposed to give an insight to the influence of controller parameters in achieving an enhanced output performance and how the time of sample period affect the error of practical stability will be illustrated. The novelty of this controller in comparison to other schemes lies in the improved performance of practical stability.

• 한국시뮬레이션학회논문지
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• 제28권2호
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• pp.149-158
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• 2019

본 연구에서는 전장이나 재난 환경과 같은 인간이 투입되기 힘든 환경에서 인간을 대신하여 부상자 구조 및 위험물 처리 목적으로 개발된 구조로봇의 효율적 개발을 위한 통합 M&S 프레임워크를 소개한다. 개발된 통합 M&S 프레임워크는 계층화, 모듈화된 통합운동제어 소프트웨어의 구조에 기인하여 통합운동제어 소프트웨어 구조는 동일하게 이용하며 로봇 플랫폼을 시뮬레이션 프로그램으로 대체하여 SILS(Software-in-the-Loop Simulation) 개념의 M&S를 가능하게 하였다. 이를 활용하여 로봇 설계 및 로봇 제어 기술의 성능 검증 등의 개발 전 과정을 효율적으로 수행하였고, 비정형 환경에서의 원격 운용성 향상도 가져왔다. 통합 M&S 프레임워크의 적극적인 활용을 통해 구조로봇의 성공적인 개발 및 성능 확인을 완료하였으며, 구조로봇의 주요 기술 중 하나인 가변형상 제어를 통한 주행 안정화 기술 개발 과정에 적용된 통합 M&S 프레임워크의 사례를 통해 효용성을 확인한다.

• Asia pacific journal of information systems
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• 제12권1호
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• pp.67-85
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• 2002

This study attempts (1) to analyze the changing pattern of organizational control by investigating the impacts of ERP implementations on the determinants of organizational control types and (2) to compare the performance variances based on the fitness between implementation of ERP and the changed mode of organizational control. Research results reveal that firms with ERP shows high degree of information integration, which partially affects the determinants of organizational control types. Also, results indicate that firms now with ERP shows the higher levels of both behavior and output control than without ERP, and the magnitude of change in behavior control level was greater than that of output control level. Finally, this research suggests that while the firms that implemented ERP for the purpose of quality and service improvement need to more focus on behavior control than on output control, the firms for the purpose of cost reduction need to excercise more output control in order to establish a cost effective control strategy.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.751-760
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• 2017

This paper proposes a point of common coupling (PCC) voltage compensation algorithm using a current limitation strategy for use in distributed generation (DG). The proposed strategy maintains the PCC voltage by prioritizing currents when an output current reference is larger than the current capacity of the power condition system (PCS) of the DG. With this strategy, the DG outputs the active current, reactive current, and the negative sequence current. The DG uses the reactive current for maintaining the PCC voltage within a normal range; the negative sequence current is used for reducing the PCC voltage unbalance. The proposed method was verified using PSIM simulation and experimental results.

• 대한교통학회지
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• 제26권6호
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• pp.81-89
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• 2008

도시고속도로의 확대와 더불어 일반 간선도로에 접속되는 도시고속도로 진출램프 또한 증가하고 있으며, 진출램프가 혼잡한 간선도로 상에 접속시 간선도로에서의 차량 혼입으로 인한 혼잡 가중 및 이로 인한 진출램프에서의 대기행렬이 역류하여 도시고속도로 본선에 혼잡의 영향이 미치는 현상이 발생하고 있다. 이러한 문제를 해결하고자 본 연구에서는 도시고속도로 진출부 교차로 제어의 개념으로 접근하여 도시고속도로 진출차량을 포함한 간선도로에서의 교통상황(하류부 링크 포함)까지도 고려하여 간선도로가 포화된 경우, 진출램프가 포화된 경우, 간선도로와 진출램프 모두 포화된 경우로 나누어 각 교통상황별 제어전략의 효과를 분석하였으며, 제어전략의 효과에 영향을 미치는 기하조건을 반영하기 위하여 COSMOS에서 제시한 하류부 링크저장공간 200m를 기준으로 이상일 때와 이하일 때로 구분하여 전체 6가지 CASE에 대한 감응식 신호제어전략 적용 전 후의 효과를 평가하였다. 그 결과, 전체 네트워크 차원에서 하류부링크 저장공간 200m 이하일 때 CASE I${\sim}$III에서는 4.4%${\sim}$6.2%, 200m 이상일 때 CASE Ⅳ${\sim}$Ⅵ에서는 6.1%${\sim}$16.2%의 지체 감소 효과가 발생하였으며, 상대적으로 하류부 링크저장공간이 큰 네트워크에서 효과가 더욱 크게 발생한 것으로 분석되었다.

• The Plant Pathology Journal
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• 제29권3호
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• pp.294-304
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• 2013

To improve the integrated pest management (IPM) of hot pepper, field study was conducted in Hwasung from 2010 to 2012 and an IPM system was developed to help growers decide when to apply pesticides to control anthracnose, tobacco budworm, Phytophthora blight, bacterial wilt, and bacterial leaf spot. The three field treatments consisted of IPM sprays following the forecast model advisory, a periodic spray at 7-to-10-day intervals, and no spray (control). The number of annual pesticide applications for the IPM treatment ranged from six to eight, whereas the plots subjected to the periodic treatment received pesticide 11 or 12 times annually for three years. Compared to the former strategy, our improved IPM strategy features more intense pest management, with frequent spraying for anthracnose and mixed spraying for tobacco budworm or Phytophthora blight. The incidences for no pesticide control in 2010, 2011, and 2012 were 91, 97.6, and 41.4%, respectively. Conversely, the incidences for the IPM treatment for those years were 7.6, 62.6, and 2%, and the yields from IPM-treated plots were 48.6 kg, 12.1 kg, and 48.8 kg. The incidence and yield in the IPM-treated plots were almost the same as those of the periodic treatment except in 2011, in which no unnecessary sprays were given, meaning that the IPM control was quite successful. From reviewing eight years of field work, sophisticated forecasts that optimize pesticide spray timing reveal that reliance on pesticides can be reduced without compromising yield. Eco-friendly strategies can be implemented in the pest management of hot pepper.