• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 전기설비
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• pp.19-22
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• 2006

The CMD(Condition Monitoring & Diagnosis) System is used to monitor and analyze the PD(Partial Discharge), Arc, Temperature, Pressure, Gas in Oil and so on for reliability and availability of the substation. Although this system comes into the spotlight as the forecast and management of the failure and fault, there are some problems. For example, the unified standard was not defined, and the effective management of the layed communication network does not performed, limitation of physical space, etc. To resolve above problems, this paper suggests the IEC61850 compatible eCMD system architecture for monitoring and analyzing the CMD factor in substations. The suggested eCMD system consists of CMD-LU(Condition Monitoring & Diagnosis-Local Unit), IED(Intelligent Electronic Device), and engineering centers. The IEC61850 is the international standard that defines communication networks and system in substation.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1769-1776
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• 2016

For on-line partial discharge (PD) monitoring of rotating machines, a novel sensor is proposed, which can be installed on the power lead inside the terminal box of the machine. The sensor has been designed to have high capacitance, and minimal reflection of measured pulses. As a sensitivity of the sensor, transfer impedance $Z_t$ has been measured and compared to conventional coupler-type sensors. A simple method is presented for measuring $Z_t$ of coupler sensors, using a vector network analyzer and a practical lead-cable of rotating machine. Through this method, it became possible to measure the $Z_t$ of coupler sensors including the installation environment of them. The $Z_t$ of the proposed sensor is higher than that of same sized other conventional couplers at frequencies between 30 and 92 MHz. Another sensitivity test has been performed using a PD calibrator as a test pulse source. The proposed sensor has higher measured peak voltage than the conventional coupler type sensors when the same charges were input.

• 한국물환경학회지
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• 제20권3호
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• pp.245-250
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• 2004

This study investigated the micropollutants present in raw water supplied for the several drinking water treatment plants in Seoul. The target sample waters were collected from the several sites, such as Jayang (JY), Kuui (KI), Paldang (PD) and Kangbuk (KB) at the Han-River stream. The analytical method used in this study enable us to detect about 300 kinds of chemicals commonly found in surface water at ppt level by GC-ion trap MS. In this study, the consideration on the analytic results focused on the four hazardous organics, such as benzenes, phenols, phthalates and pesticides. The numbers of each detected micropollutant were 1~8 kinds for benzenes, 1~7 kinds for phenols, 5~7 kinds for phthalates and 1~9 kinds for pesticides. For the pesticides, the higher concentration was detected in the water samples collected from PD and KB adjacent to the farming area, and at June and July, which is the busy farming season. The total concentrations of each micropollutants detected at all the sites were significantly lower than those of drinking water regulation in Korea as well as other advanced countries. However, the frequently detected micropollutants requires the steady and precise monitoring for the effective management of drinking water source.

• Ocean Systems Engineering
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• 제10권4호
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• pp.373-397
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• 2020

Heave compensation is a vital part of various marine and offshore operations. It is used in various applications, including the transfer of cargo between two vessels in the open ocean, installation of topsides of an offshore structure, offshore drilling and for surveillance, reconnaissance and monitoring. These applications typically involve a load suspended from a hydraulically powered winch that is connected to a vessel that is undergoing dynamic motion in the ocean environment. The goal in these applications is to design a winch controller to keep the load at a regulated height by rejecting the net heave motion of the winch arising from ship motions at sea. In this study, we analyze and compare the performance of various control algorithms in stabilizing a suspended load while the vessel is subjected to changing sea conditions. The KCS container ship is chosen as the vessel undergoing dynamic motion in the ocean. The negative of the net heave motion at the winch is provided as a reference signal to track. Various control strategies like Proportional-Derivative (PD) Control, Model Predictive Control (MPC), Linear Quadratic Integral Control (LQI), and Sliding Mode Control (SMC) are implemented and tuned for effective heave compensation. The performance of the controllers is compared with respect to heave compensation, disturbance rejection and noise attenuation.

• The Korean Journal of Physiology and Pharmacology
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• 제17권4호
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• pp.299-306
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• 2013

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been widely used as a treatment for the movement disturbances caused by Parkinson's disease (PD). Despite successful application of DBS, its mechanism of therapeutic effect is not clearly understood. Because PD results from the degeneration of dopamine neurons that affect the basal ganglia (BG) network, investigation of neuronal responses of BG neurons during STN DBS can provide informative insights for the understanding of the mechanism of therapeutic effect. However, it is difficult to observe neuronal activity during DBS because of large stimulation artifacts. Here, we report the observation of neuronal activities of the globus pallidus (GP) in normal and PD model rats during electrical stimulation of the STN. A custom artifact removal technique was devised to enable monitoring of neural activity during stimulation. We investigated how GP neurons responded to STN stimulation at various stimulation frequencies (10, 50, 90 and 130 Hz). It was observed that activities of GP neurons were modulated by stimulation frequency of the STN and significantly inhibited by high frequency stimulation above 50 Hz. These findings suggest that GP neuronal activity is effectively modulated by STN stimulation and strongly dependent on the frequency of stimulation.

• 대한건축학회논문집:계획계
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• 제35권10호
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• pp.83-90
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• 2019

The purpose of the present study is to confirm, through quantitative indices, changes arising with the implementation of urban regeneration projects, with a specific focus on the case of Dongnam-gu, Cheonan, one of the 13 priority rgions in urban regeneration. By utilizing quantitative data including resident population, floating population, revenue, number of small business persons, number of startup companies, and number of licensed buildings, the study confirmed changes in Dongnam-gu and other urban regeneration areas. The study compared monitoring results and implemented project policies to confirm changes within the area as a result of project implementation. Additionally, resident perception toward business districts was surveyed to confirm changes in perception and opinion, and monitoring indices were used to confirm changes as a result of project implementation. Accordingly, the study presented a plan to carry out the assessment of urban regeneration projects, which can be employed as data for conducting future urban regeneration projects. Urban regeneration projects are carried out for the long-term. Therefore, based on monitoring and investigative data, they require constant policy suggestions and periodic monitoring in accordance with changes resulting from project implementation. With regards to the effective range of urban regeneration projects, the study confirmed the possibility of an effect not only in the area of project implementation but also in surrounding areas. However, because the study merely confirms changes in Dongnam-gu, Cheonan, additional research is necessary to ascertain assessment plans suitable to the different types and regional characteristics of urban regeneration projects.

• ETRI Journal
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• 제31권6호
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• pp.770-777
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• 2009

We have developed a fully functional reconfigurable optical add-drop multiplexer (ROADM) switch module using a polymer integrated photonic lightwave circuit technology. The polymer variable optical attenuator (VOA) array and digital optical switch array are integrated into one polymer PLC chip and packaged to form a 10-channel VOA integrated optical switch module. Four of these optical switch modules are used in the ROADM switch module to execute 40-channel switching and power equalization. As a wavelength division multiplexer (WDM) filter device, two C-band 40-channel athermal arrayed waveguide grating WDMs are used in the ROADM module. Optical power monitoring of each channel is carried out using a 5% tap PD. A controller and firmware having the functions of a 40-channel switch and VOA control, optical power monitoring, as well as TEC temperature control, and data communication interfaces are also developed in this study.

• 전자공학회논문지CI
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• 제45권5호
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• pp.155-161
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• 2008

자동화된 건강관리 모니터링은 많은 시간이 소요되고, 많은 문제들이 발생할 수 있다. 왜냐하면 정시에 환자들의 건강 상태에 대한 모니터링 정보를 제공받기 어렵기 때문이다 이 논문에서는 임베디드된 건강 관리 서비스가 iSCSI 프로토콜에 의해 제안된다. 이 프로토콜은 자동화된 멀티에이전트와 제한된 자원의 디바이스들(예. PD4 스마트폰, 테블릿PC)의 협력체계에 기반을 두고 있다. 이 둘의 협력체계는 쌍방향 iSCSI 프로토콜에 의해 유지된다. 자동화된 건강관리 제어는 반복되는 방식에서 매우 유용할 수 있다. 완전 집중화된 제어에서는 이 방법이 적용될 수 없다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.101-103
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• 2004

본 연구는 전력 계통에 상용화된 $SF_6$ GIS(Gas Insulated Switchgear) 내부에서 발생되는 부분방전 검출 방법을 개발하기 위하여, GIS의 내부에 유입되거나 생산과정에서 형성 될 수 있는 세 가지 결함들을 연구용 GIS 내부에 모의하였으며 또한 특성이 다른 센서(UHF, CT, AE)를 제작 또는 이용하여 그 부분방전 패턴 결과와 주파수 분석 결과를 상호 비교하였다. 실험결과에 의하면, 동일한 결함에 의하여 센서의 검출 결과는 다르게 나타나거나 전혀 검출이 되지 않음이 밝혀졌다. 따라서, 부분방전 패턴분석을 하나의 분석방법에 의존하는 것은 바람직하지 못한 것으로 사료되며 신뢰성 있는 GIS 진단을 위하여 적합한 센서개발 및 두 가지 이상의 분석 방법이 병행되는 것이 절대적으로 필요한 것으로 사료된다.

• 센서학회지
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• 제6권5호
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• pp.369-375
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• 1997

$SnO_{2}$에 $V_{2}O_{5}/ThO_{2}/Pd$를 도핑하여 제조된 센서는 약 $500^{\circ}C$의 높은 센서 온도에서 CO에 대해 우수한 선택도와 안전성 및 빠른 응답특성을 보였다. 특히, $V_{2}O_{5}$를 약 3.0 wt.% 첨가하여 선택도에 있어서 CO 감도에 대해 $NO_{x}$, $C_{3}H_{8}$, $CH_{4}$ 및 $SO_{2}$같은 많은 간섭가스들의 영향이 적음을 알았다. 센서 제조는 $V_{2}O_{5}$(3.0 wt.%), $ThO_{2}$(1.5wt.%), Pd(1.0 wt.%)의 촉매물질과 함께 기존에 잘 알려진 후막기술을 이용하였다. 일반적으로 연소배가스처럼 $NO_{x}$와 CO가 혼합되어 있는 복합가스의 경우, $SnO_{2}$계 반도체 센서로는 CO만의 검지는 $NO_{x}$ 간섭 때문에 대단히 어렵다. 본 센서는 공연비제어를 요하는 자동차나 보일러 시스템의 연소배가스의 측정과 감시에 사용할 수 있을 것이다.