• 전기학회논문지
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• 제64권8호
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• pp.1161-1167
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• 2015

Distribution Management System(DMS) ienhancing distribution automation system-based operation efficiency is an optimized system by various operational applications in a distribution network. DMS employs various applications like topology reconfiguration, volt/var control, and restoration at events such as overload, voltage violation, and a fault in a distribution system. An operation efficiency to employ multi-applications as restoration with short-term load forecasting is higher than a performance by a single application; and the applications are accomplished by an operator’s control. Applications’ combination is determined by various alarm information which means critical issues in order to operate a distribution system. Thus, this paper proposes an application management system which can configure application combination, control applications depending on alarm information and check their performance condition. The proposed application management system can be customized by operator easily and have high operation efficiency and reliability because it is worked by reviewed alarm information from operator.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제17권1호
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• pp.41-50
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• 2011

This paper assesses the evidence of the built environments' impact on patients' and staff's well-being. It also introduces evidence-based design (EBD) and discusses barriers and solutions for promoting EBD. EBD is an informed approach to design by improving design decisions based on best available knowledge. Designers should provide psychologically and physically supportive environments to promote occupants' well-being. There is increasing evidence that a poorly designed environment elicits negative feelings and stress. Better design will lead to better outcomes especially when it applied to a vulnerable population such as patients, children, and the elderly. Due to high demands of promoting patients' health, healthcare providers and professional designers have been searching for evidence to create healing environments. EBD has been well received in healthcare facilities design and is expanding to other types of environmental design such as educational and commercial design. Design firms should consider EBD as a value-added component of design to meet current and future challenges. It is important for designers to realize that engaging in EBD is not a rejection of creativity, but a means by which to scrutinize their design projects. With critical literature reviews on healing environments, there is sufficient evidence that well-designed environments can promote patients' and medical staff's health outcomes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.3181-3183
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• 2000

As the fact that the simple data of text and sound in early year have been changed to be high quality images and sounds. PLL(Phase-Locked Loop) system plays an important role in communication system. VCO(Voltage Controlled Oscillator) is the most important part in PLL system because it can have critical effects on operation of PLL. Recently, it has been raised the necessity of high speed and high accuracy circuit application. In this paper, a new differential voltage clamped VCO using negative-skewed path is suggested. Using a dual-delay scheme to implement the VCO, higher operation frequency and wider tuning are achieved simultaneously. The dual-delay scheme means that both the negative skewed delay paths and the normal delay paths exist in the same ring oscillator. The negative skewed delay paths decrease the unit delay time of the ring oscillator below the single inverter delay time. As a result, higher operation frequency can be obtained. The whole characteristics of VCO are simulated by using HSPICE. Simulation results show that the resulting operating frequencies are 50% higher than those obtainable from the conventional approaches.

• 전기학회논문지P
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• 제51권4호
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• pp.175-185
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• 2002

In this paper, a new fully digital current control method of UPS inverter, which is based on an internal model control, is proposed. In the proposed control system, overshoots and oscillations due to the computation time-delay are compensated by explicit incorporation of the time-delay in the current control loop transfer function. The internal model controller is adopted to a second order deadbeat reference-to-output response which means that its response reaches the reference in two sampling time including computational time-delays. That is, the average current of filter capacitor is been exactly equal to the reference current with a time lag of two sampling intervals. Therefore, this method has an essentially overshoot free reference-to-output response with a minimum possible rise time. The effectiveness of the proposed control system has been verified by the simulation and experimental respectively. From the simulation and experimental results, the proposed system is achieved the robust characteristics to the calculation time delay and parameter variation as well as very fast dynamic performance, thus it can be effectively applied to the power supply for the critical load.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.702-705
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• 1998

To be applied to electrical equipment HTSC tapes have to endure external stress and so on. The critical current density has been shown depending on the mechanical properties, strain and bending stress. AC loss reduction is primary concern in the development of such high-efficiency equipment. AC losses in Bi-2223 silver-sheathed tapes, both single and multi-filamentary, were investigated by means of AC magnetization techniques. The results were compared with the hysteresis loss equation based on Bean model and the eddy current loss equation. The AC loss of the mono-filamentary tape was the hysteresis. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.

• 대한화학회지
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• 제39권12호
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• pp.896-901
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• 1995

순수 물 및 NaCl의 수용액에서 Sodium Dodecyl Sulfate(SDS)와 Tetraethylene glycol monodode-cyl ether(TGME)의 혼합계면활성제가 $25^{\circ}C$에서 나타내는 임계미셀농도값(CMC$^*$)들을 표면장력계로 측정하였으며, 이들 CMC$^*$값들이 음이온 계면활성제인 SDS의 몰분율 조성(${\alpha}_1$)과 첨과제인 NaCl의 농도에 따라 어떻게 변화하는지를 조사하였다. 유사상태분리모델을 기초로하는 비이상적 혼합비셀모델을 적용함으로써 측정된 CMC$^*$값들로부터 SDS/TGME 혼합계면활성제의 미셀화에 대한 여러가지 열역학적 함수값들을 계산하여 분석하였다.

• Smart Structures and Systems
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• 제8권2호
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• pp.205-217
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• 2011

This article describes the research work involving the implementation of an Active Bracing System aimed at the modification of the initial dynamics of a laboratorial building structure to a new desired dynamics. By means of an adequate control force it is possible to assign an entirely new dynamics to a system by moving its natural frequencies and damping ratios to different values with the purpose of achieving a better overall structural response to external loads. In Civil Engineering applications, the most common procedures for controlling vibrations in structures include changing natural frequencies in order to avoid resonance phenomena and increasing the damping ratios of the critical vibration modes. In this study, the actual implementation of an active system is demonstrated, which is able to perform such modifications in a wide frequency range; to this end, a plane frame physical model with 4 degrees-of-freedom is used. The Active Bracing System developed is actuated by a linear motor controlled by an algorithm based on pole assignment strategy. The efficiency of this control system is verified experimentally by analyzing the control effect obtained with the modification of the initial dynamic parameters of the plane frame and observing the subsequent structural response.

• 의학교육논단
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• 제16권3호
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• pp.147-155
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• 2014

Medical ethics has been integrated into the curriculum for medical education in Korea for over 30 years now. There have been many attempts to establish standards for the educational objectives and curriculum, including establishing learning outcomes and publishing medical ethics textbooks in Korean. However, this task is not easy for several reasons: the interdisciplinary nature of the subject, educators' lack of experience, and the lack of a consensus on the criteria that would be effective educational goals. In this article, the author explores (1) the need for reflection on the education itself, (2) two perspectives of medical ethics education, (3) critical perspectives on the effectiveness of the current medical ethics education, and (4) the variety of modalities of medical ethics education. Further, the author proposes a way to teach medical ethics in Korea. The contents and means are closely related to the question of philosophy of medical education: "Should professional ethics education be 'realistic' or 'idealistic'?" Ethics requires educators to be open to new learning experiences and to ethical development. Medical Ethics education should be relevant to everyday clinical experiences and, at the same time provide students and educators to critically review their ethical perspective through reflections.

• 한국기계가공학회지
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• 제10권2호
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• pp.79-83
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• 2011

Magnetic seal uses a magnetic fluid to seal a gap between a rotating shaft and housing. It is distinguished from other kinds of seals from the fact that solid contact does not occur in the seal. This implies that it is free from solid rubbing thus dustless and provides a clean circumstance. That is the reason why the magnetic seal is used exclusively for most of vacuum chambers in semiconductor process where dustless clean circumstance is critical. A magnetic seal has been developed of which design parameters are determined based on published data, and an air pressure test has been done to examine its sealing capability. Effects of some design parameters have been studied through FEM analysis. The results show some notable aspects of design parameters and provide suggestions for developing the seals. Regarding the sealing capacity of the magnetic seal the factor to match the theoretical value with the actual one was found to be 0.4~0.7, which means still there is some discrepancy between theory and actual.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.678-685
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• 2016

The standard high-availability seamless redundancy (HSR) protocol utilizes duplicated frame copies of each sent frame for zero fail over time. This means that even in cases of a node or link failure, the destination node will receive at least one copy of the sent frame, resulting in no network downtime. However, the standard HSR is mostly based on the electrical signal connection inside the node, which leads to the production of considerable latency at each node due to frame processing. Therefore, in a large scale HSR ring network, the accumulated latencies become significant and can often restrict the mission-critical real-time application of HSR. In this paper, we present a novel design for optical HSR (OHSR) that uses beam splitting/combining techniques. The proposed OHSR passes the frames directly to adjacent nodes without frame processing at each node, thereby theoretically generating no latency in any node. Various simulations for network samples, made to validate the OHSR design and its performance, show that the OHSR outperforms the standard HSR.