• Nuclear Engineering and Technology
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• 제47권1호
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• pp.66-73
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• 2015

Background: A numerical simulation was carried out to investigate the difference between internal and external heat-flux distributions at the reactor vessel wall under in-vessel retention through external reactor vessel cooling (IVR-ERVC). Methods: Total loss of feed water, station blackout, and large break loss of coolant accidents were selected as the severe accident scenarios, and a transient analysis using the element-birth-and-death technique was conducted to reflect the vessel erosion (vessel wall thickness change) effect. Results: It was found that the maximum heat flux at the focusing region was decreased at least 10% when considering the two-dimensional heat conduction at the reactor vessel wall. Conclusion: The results show that a higher thermal margin for the IVR-ERVC strategy can be achieved in the focusing region. In addition, sensitivity studies revealed that the heat flux and reactor vessel thickness are dominantly affected by the molten corium pool formation according to the accident scenario.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 추계학술발표회요약집
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• pp.190-190
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• 1999

CHF (Critical heat flux) on the external surface of the reactor vessel lower head is major key in the evaluation on the feasibility of IVR-EVC (In-Vessel Retention through External Vessel Cooling) concept. To identify the CHF on the external surface, considerable works have been performed. Through the review on the previous works related to the CHF on the external surface, liquid subcooling, induced flow along the external surface, ICI (In-Core Instrument) nozzle and minimum gap are identified as major parameters. According to the present analysis, the effects of the ICI nozzle and minimum gap on CHF are pronounced at the upstream of test vessel: on the other hand, the induced flow considerably affects the CHF at downstream of test vessel. In addition, the subcooling effect is shown at all of test vessel, and decreases with the increase in the elevation of test vessel. In the real application of the IVR-EVC concept, vertical position is known as a limiting position, at which thermal margin is the minimum. So, it is very important to precisely predict the CHF at vertical position in a viewpoint of gaining more thermal margins. However, the effects of the liquid subcooling and induced flow do not seem to be adequately included in the CHF correlations suggested by previous works, especially at the downstream positions.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1504-1507
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• 2007

Depth data for is very important data for 3D display. Disparity and depth data makes users to feel 3D effect. We used stereo camera to measure depth and made fast algorithm to get in real time. This vision system can be substituted for expensive laser system.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.459-462
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• 2004

본 연구에서는 기존의 전통적인 IVR 시스템이 갖는 제약을 해결할 수 있는 XML 포맷을 가지는 VoireXML 문서를 브라우징할 수 있는 Voice 브라우저를 설계ㆍ구현하였다. VoiceXML로 기술된 다이얼로고를 VoiceXML 인터프리터를 통하여 해석하고 추출된 폼을 FIA로 해석하게 하였으며 음성인식 엔진의 컴포넌트를 이용하여 Grammar 컴파일 및 음성 입ㆍ출력이 가능하도록 하였다. 본 연구의 브라우저를 기반으로 하는 시스템은 음성 언어 어플리케이션을 개발할 시에 음성 인식과 같은 복잡한 기술을 이용하지 않아도 되며 현재 웹 개발의 이점을 이용할 수 있다.

• 인터넷정보학회논문지
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• 제6권1호
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• pp.39-50
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• 2005

음성 DB는 음성학, 음성인식, 음성합성 등을 연구할 때 가장 기본적으로 필요한 요소이다. 음성 DB의 양과 질이 개발하고자하는 시스템의 성능을 좌우한다고 할 정도로 음성 DB의 중요성 및 역할은 막중하다. 최근 음성포탈을 비롯한 다양한 전화 서비스 기술의 발달로 인하여 전화 음성 DB 수집의 필요성이 시급한 상황이다. 기존 CTI 분야의 IVR 애플리케이션 전화음성 DB 수집 시스템은 C/C++언어나 전용 개발 도구를 사용하여 이루어져 왔으며, 이로 인하여 각 응용서비스간 자원의 재활용이 어려운 실정이며 많은 인력과 시간을 필요하다는 문제점을 가지고 있다. 그러나, VoiceXML의 전화 음성 DB 수집시스템은 XML에 내포된 태그형식을 갖는 언어로써 쉽고, 간단한 문법체계를 가지고 있어 조금만 노력을 기울이면 손쉽게 작성할 수 있어 인력과 시간을 절약할 수 있는 장점을 가지고 있다. 또한 단지 웹서버에 연결된 DB의 내용만을 변경함으로써 다양한 전화 음성 DB를 수집할 수 있는 장점을 가지고 있다. 본 논문에서는 음성인식이나 음성합성 등 음성정보처리기술의 개발에 가장 중요한 요소인 음성 DB를 Voiceful을 사용하여 전화 음성 DB를 수집하는 시스템을 소개한다.

• 한국방사선학회논문지
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• 제6권1호
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• pp.11-17
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• 2012

중재적 방사선 시술 시 환자의 피폭선량을 시술별로 분류하여 측정 및 평가하여 안전관리 자료로 활용하고자 하였다. 검사는 시술별(TACE, EVAR, Iliac stent, Lower Limb, BAE, Embolization, PTBD, PTGBD, Abscess, Nephrostomy)로 투시시간, 면적선량, 영상획득이미지 수를 측정하였다. 시술별 분석결과 비혈관계 검사에서 전반적으로 낮은 값을 보였으며, 혈관계 검사에서는 IVC filter를 제외한 모든 검사에서 높은 값을 나타냈다. 투시시간은 EVAR가 24m30s로 가장 높았고, 면적선량 또한 EVAR가 236 $Gy/cm^2$로 가장 높았다. 면적선량률은 TACE가 22.8 $Gy/cm^2$로 높게 나타났다. 이 결과를 토대로 중재적 방사선시술시 환자피폭선량에 대한 기준선량을 제시하고자 한다.

• Nuclear Engineering and Technology
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• 제48권6호
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• pp.1330-1337
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• 2016

A visualization test of the fuel-coolant interaction in the Test for Real cOrium Interaction with water (TROI) test facility was carried out. To experimentally simulate the In-Vessel corium Retention (IVR)- External Reactor Vessel Cooling (ERVC) conditions, prototypic corium was released directly into the coolant water without a free fall in a gas phase before making contact with the coolant. Corium (34.39 kg) consisting of uranium oxide and zirconium oxide with a weight ratio of 8:2 was superheated, and 22.54 kg of the 34.39 kg corium was passed through water contained in a transparent interaction vessel. An image of the corium jet behavior in the coolant was taken by a high-speed camera every millisecond. Thermocouple junctions installed in the vertical direction of the coolant were cut sequentially by the falling corium jet. It was clearly observed that the visualization image of the corium jet taken during the fuel-coolant interaction corresponded with the temperature variations in the direction of the falling melt. The corium penetrated through the coolant, and the jet leading edge velocity was 2.0 m/s. Debris smaller than 1 mm was 15% of the total weight of the debris collected after a fuel-coolant interaction test, and the mass median diameter was 2.9 mm.

• 대한음성학회지:말소리
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• 제56호
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• pp.135-145
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• 2005

In this paper, a WiFi phone system with distributed speech recognition is implemented. The WiFi phone with voice-activated dialing and its functions are explained. Features of the input speech are extracted and are sent to the interactive voice response (IVR) server according to the real-time transport protocol (RTP). Feature extraction is based on the European Telecommunication Standards Institute (ETSI) standard front-end, but is modified to reduce the processing time. The time for front-end processing on a WiFi phone is compared with that in a PC.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.181-184
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• 2002

CFD calculations are carried out to investigate the turbulent flow characteristics inside the duct of marine waterjet propulsors. The Reynolds-averaged Wavier-Stokes equations are solved using a finite-volume method. Standard $k-{\varepsilon}$ model and realizable $k-{\varepsilon}$ model are evaluated with an existing experimental data. Multi-block grid topology is adopted to describe the details of complex duct geometry. The present numerical methods are applied to the preliminary duct design of new waterjet propulsor system. Four different influx conditions are simulated to find out pressure and velocity distribution inside the intake duct. Attention is also paid upon the possible flow separation inside the waterjet duct. It is found that CFD tools can be used for the initial evaluation of inflow condition into the impeller of waterjet propulsor system.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.13-16
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• 2002

Recent topics on quality assurance (QA) of X-ray diagnosis in Japan were reported in this presentation. These were related to mass screening mammography (MMG), lung screening CT (LSCT), skin injury caused by interventional radiology (IVR) and traceable system of dosimeters for x-ray diagnosis. In these successful stories, the author would like to stress the cooperation of all the medical am: clinical staff including medical doctors, radiological technologists, medical physicists, manufacturers of medical devices and others.