• Journal of Power Electronics
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• 제19권3호
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• pp.691-701
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• 2019

To solve the problems in the contact charging of inspection robots, a wireless charging system for inspection robots and a control strategy are introduced in this paper. Circuit models of a wireless power system with a compound compensation circuit and a three-phase Class-D resonant inverter are set up based on circuit theory. An output voltage control method based on the equal spread regulation of the phase difference between adjacent phases and the parameter correction method in the primary compound compensation circuit are proposed. The dynamic characteristics of the key parameters varying with the secondary coil position are obtained to further investigate the adaptive location scheme during the access and exit processes of moving robots. Combining the output voltage control method and the adaptive location scheme, a transition control strategy for the standby and operation modes of the wireless charging systems for inspection robots is put forward to realize the system characteristics including the low standby power in the standby mode and the high receiving power in the operation mode. Finally, experiments are designed and conducted to verify the correctness of the theoretical research.

• Journal of Power Electronics
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• 제12권3호
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• pp.495-502
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• 2012

This paper presents an improved grid voltage control strategy for wind farms with doubly-fed induction generators (DFIGs) connected to distribution networks based on an analysis of the operation limits of DFIG systems. A modified reactive power limit calculation method in different operation states is proposed and a reactive power control strategy during grid voltage dips/rises is further discussed. A control strategy for compensating unbalanced grid voltage, based on DFIG systems, by injecting negative sequence current into the grid through the grid side converter (GSC) is proposed. In addition, the negative current limit of the GSC is discussed. The distribution principle of the negative sequence current among the different DFIG systems in a wind farm is also introduced. The validity of the proposed voltage control strategy is demonstrated by Matlab/Simulink simulations. It is shown that the stability of a wind farm and the power grid can be improved with the proposed strategy.

• Journal of Chest Surgery
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• 제45권4호
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• pp.213-224
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• 2012

Tetralogy of Fallot (TOF) is an index lesion for all paediatric and congenital heart surgeons. In designing an appropriate operation for children with TOF, the predicted postoperative physiology must be taken into account, both for the short and long term. A favourable balance between pulmonary stenosis (PS) and pulmonary insufficiency (PI) may be critical for preservation of biventricular function. A unified repair strategy to limit both residual PS and PI is presented, along with supportive experimental evidence. A strategy for dealing with coronary anomalies and some comments regarding best timing of operation are also included.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.198-201
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• 1993

In this paper a numerical model of the industrial cogeneration system which have a thermal storage tank is proposed for the short-term operation strategy. Short-term operation costs of towing cycle and bottoming cycle are calculated by using the proposed model of a thermal storage tank. Simulation results of four cases are compared and analyzed each other. By these simulations which are similar to real operation circumstances, the validity of the proposed model is verified.

• Journal of Information Technology Applications and Management
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• 제25권3호
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• pp.29-41
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• 2018

The purpose of constructing university information system is for improvement in diversification and throughput of information, streamlines business processes, rapid exchange of information, sharing of information, decision-making information, and securing educational facilities. Similar to business information technology system, university information system does not have a review system for sharing and overlapping investment of information. Due to the lack of project management for outsourcing and vulnerability of system suitability, system audit is absolutely needed for the university information system. This paper especially focuses on an operational phase in the audit of university information system. Additionally, we proposed operating model and checklists of the university information system based on Management Guidelines of ITIL V3 Operational and Information System. We derived the checklists of operation audit by each domain of service strategy, service design, service transition, service operation, and continual service improvement. As the result, this study appear to have more than average satisfaction the suitability results were.

• 한국항해항만학회지
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• 제34권7호
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• pp.595-601
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• 2010

This paper aims to diagnose the strategy execution ability and to provide corresponding measures for Korean oceanic shipping companies. The analysis method is the t-test between importance awareness and Corresponding ability for strategy execution diagnosis index(XPP). According to the diagnosed results, the strategy development is unsatisfactory because the strategy implemented does not adhere to concurrent environmental change. Moreover, the execution of the strategy is also unsatisfactory. Therefore, an evaluation shows that there is a need for a SWOT analysis using BSC, an organization structure to strengthen the strategy execution ability and the support from the market condition analysis prediction center.

• 한국ITS학회 논문지
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• 제22권1호
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• pp.172-191
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• 2023

본 연구는 국내 자율주행차 시범운행지구 지정 및 운영에 따라 자율주행차 혼재 시 예상되는 교통 변화를 분석하여, 시범운행지구의 자율주행차 혼재 교통운영전략 수립을 목적으로 한다. 시범운행지구가 자율주행차의 안정적 상용화를 위한 테스트 베드로서의 역할을 해내기 위해서는 안전하고 효율적인 교통운영전략 수립이 요구됨에도 현재까지는 자율주행차 혼재에 따른 교통운영전략은 부재하다. 이에 본 연구에서는 자율주행차 혼재 시 자율주행차 시범운행 지구의 교통운영전략을 수립하고자 한다. 자율주행차 도입 단계별 교통운영전략 수립을 위해 자율주행차 혼입률에 따른 교통 효율성 및 안전성 분석을 수행하였으며, 분석 결과를 토대로 자율주행차 혼입률 30%, 70%를 기준으로 도입기, 과도기, 안정기로 구분하였다. 본 연구에서 자율주행차 도입 단계별로 제시한 교통류와 교통안전 관점의 교통운영전략은 다음과 같다. 교통류 운영전략은 자율주행차 도입기에는 기존 도로 인프라 첨단화, 과도기에는 자율주행차 전용차로 및 일반차 마일리지 제도 운영, 안정기에는 자율주행차 전용차로 확대 운영 및 제한속도 완화를 제시하였다. 교통안전 전략은 도입기에는 자율주행차 사고 발생 대응 매뉴얼 및 법 제도 마련, 과도기에는 자율주행차 사고 원인 분석 및 예방정책 시행, 안정기에는 자율주행차 시스템 고도화 및 보안정책 강화를 제시하였다. 본 연구에서 제시한 교통운영전략을 통해 향후 자율주행차 시범운행지구 내 자율주행차 혼재로 인해 예상되는 교통류 및 교통안전 관에서 선제적으로 대응할 수 있을 것으로 기대된다.

• KIEAE Journal
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• 제15권4호
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• pp.37-43
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• 2015

Purpose : The study applied control strategy to reduce through optimal control and operation of pump by applying control on variable speed to the circulation pump of HVAC system in the office building. The study has the purpose to review validity of control on variable speed as ESMs(Energy Saving Measures) and establish the control technology on variable speed pump. The study performed reduction analysis of building energy and economic evaluation of pump through energy effectiveness control strategy of HVAC system. Method: The study sought possible reduction through energy control strategy which can provide proper flow fitting to building load by applying control on variable speed pump. The study applied control strategy to reduce through pressure differential set-point control and operation of pump by applying control on variable speed to the circulation pump of HVAC system in the office building. Result : The results showed that about 16-35% of pump energy could be saved by using these optimal control strategies. In the result of analysis on 10 years life cycle cost of analysis on payback period of initial investment pump, variable speed pump control showed 5.1 years.

• 산업경영시스템학회지
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• 제45권3호
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• pp.115-122
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• 2022

As cable TV, which has been leading the paid broadcasting market, has given the lead to IPTV, which has huge communication capital, its competitiveness is gradually weakening. This study examines the operation status of local cable TV and seeks ways to strengthen competitiveness for survival. To this end, we conducted data analysis such as related statistics, broadcasting industry survey reports, IPTV growth reports, CMB management indicators, paid broadcasting literature data, marketing reports, industry success stories, and marketing mix and SWOT analysis. As a result, four strategies for strengthening the survival competitiveness of local cable TV, namely joint purchase apartment marketing strategy, influencer marketing strategy, relationship marketing strategy, and digital marketing strategy were derived. Therefore, the results of this study can contribute to the improvement of the competitiveness of local cable TV, which has been with local residents through close content, and can be used as basic data for establishing marketing strategies for local cable TV in the future.

• 전기저널
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• 4호통권76호
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• pp.30-35
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• 1983