• Fire Science and Engineering
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• v.25 no.1
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• pp.50-56
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• 2011

In recently years, occurrences of lightning return strokes have been increased by global worming effect and intensity of lightning impulse voltage and current accompanied by lightning discharges has being strengthening. In Korea, 560 thousand lightning discharges happened in 200S. According to the increasing frequencies of lightning, human deaths and damages to the structure have been increased steadily. Electric fire caused by lightning return strokes due to the breakdown between power line and ground line from the ground potential rise on a process of the lightning impulse current through to the ground. The damages of lightning were occurring at same time in the neighboring areas of the lightning point. In order to protect from the lightning stroke, we made a suggestion to use protection devices and equipotential bonding at the dangerous areas. The analysis results of electric fires caused by lightning would be utilized to investigate and to find accurate fire cause in the fire scenes.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.5
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• pp.375-384
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• 2021

The development of the European Railway Traffic Management System (ERTMS) began in 1989 as part of the European Union policy to establish a unified and interoperable railway route in Europe. It is a trend that ERTMS/ETCS(European Train Control System) is becoming an international standard in the railway signaling system. As the solution to this situation, the domestic railway signaling field is also at a time when it is more necessary to develop the technology of the train control system considering interoperability. The European Railway Agency (ERA) has proposed B3R2 (Baseline 3 Release 2) for new ETCS-equipped trains after 2020.12.31. In Korea, Baseline 2.2.0 to 2.3.0d on Gyeongbu Line, Honam Line, Jeolla Line, and Gyeongchun Line was installed and now is under operating. As the Baseline upgrade continues, technical considerations and economic considerations are an occurring trend. In this paper, we analyzed the main functions and compatibility of the currently distributed European standard ERTMS/ETCS Baseline 3 and presented a plan to apply the domestic KTCS(Korean Train Control System) Baseline in the near future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.610-615
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• 2016

Diverse accessories are used in automobiles, such as navigation systems, front and rear cameras, spoilers, and sun visors. Sun visors block sunlight so that drivers can drive safely with a better view, and they are used in many automobile designs. However, when large plastic products are manufactured using injection molding, there are many difficulties that develop, like weld lines, short shots, flow marks, imperfections, and distortion. In this study, a CAE simulation was conducted based on previous results to predict potential problems in the injection molding of large products. The flow characteristics up to complete charge for the melting resins were captured using a computer-aided engineering simulation. The temperature departure on the front part of a flow was about $10^{\circ}C$ and very stable. The practical ejecting time of the cold runner was about 70 seconds in the simulation. Finally, the capability of a suitable injection machine was calculated and recommended by prediction of the injection pressure and the die clamping force.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1723-1730
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• 2014

The use of strand wire in structure has been increased by the recent development of construction technologies. Until now, in spite of difficult problems in measuring strand stresses within PSC girders, indirect estimation with a load cell or accelerometer has been often used. In this paper, the electrical resistance strand meter for effective measurement of strand stresses is proposed with experiments considering material, location and thickness of sensor. The reliability and feasibility of the strand meter is enhanced through the experiment with 29.9m PSC girder.

• Journal of Korea Technology Innovation Society
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• v.15 no.1
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• pp.76-104
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• 2012

For many small and medium-sized enterprises (SMEs), innovation activities to lead a market with technology development and a globalization strategy tend to be a haphazard process due to a lack of capabilities. Thus, this paper aims to explore success factors of the global leading SMEs in Korea that are not only the first mover through technology innovation but also outstanding in export. The analysis utilizes data from Korean Innovation Survey (KIS) and statistical analyses such as t-test and chi-square are performed to compare global leading SMEs and normal SMEs, concentrating on various factors such as information sources, collaboration and non-technology innovation activities. The results indicate that critical success factors involve information from outside companies (information from conferences and government institutes) and government supports through logistic regression analysis. This research suggests a strategic direction for policy makers to promote innovation and growth in SMEs.

• Journal of the Korean GEO-environmental Society
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• v.11 no.7
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• pp.5-14
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• 2010

The paper processed settlement analysis using Finite Elements Method(FEM). Because Stress Distribution Ratio has to be decreased, for settlement analysis of soft clay deposit improved by sand compaction piles(SCP). Back analysis was processed comparing the measured settlements of laboratory model tests and finite element analysis where the SCP treated area was assumed as mixed ground with clay deposit rather than being a composite ground. The paper proposes a methodology which employs a compression index($C_c$) for settlement analysis of soft clay deposit improved by sand compaction piles from the back analysis. This approach is applied to a field measurement case(A revetment founded on the SCP improved clay deposit with the replacement ratio of 45%).

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.105-108
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• 1999

TTS(Text-To-Speech) 시스템 합성음성의 자연감을 개선하기 위해 하나의 언어에 대해 존재하는 운율 법칙을 정확히 구현해야 한다. 존재하는 운율 법칙을 추출하기 위해서는 방대한 분량의 언어 자료 구축이 필요하다. 그러나 이 방법은 존재하는 운율 현상이 포함된 언어자료에 대해 완벽한 운율을 파악할 수 없으므로 합성음성의 질을 좋게 할 수 없다. 본 논문은 한국어 음성의 운율을 학습하기 위해 2개의 인공 신경망을 제안한다. 하나의 신경망으로 문장의 각 음소에 대한 피치 변화를 학습시키는 것이며, 다른 하나는 에너지 변화를 학습하도록 하였다. 신경망은 BP 신경망을 이용하며 11개의 음소를 나타내기 위해 11개의 입력과, 중간 음소의 피치와 에너지 변화곡선을 근사하는 다항식 계수를 출력하도록 하였다. 신경망시스템의 학습과 평가에 앞서, 음성학적 균형잡힌 고립단어를 기반으로 의미있는 문장을 구성하였다. 문장을 남자 화자로 하여금 읽게 하고 녹음하여 음성 DB를 구축하였다. 음성 DB에 대해 각 음소의 운율 정보를 수집하여 신경망에 맞는 목표 패턴과 훈련 패턴을 작성하였다. 이 목표 패턴은 회귀분석을 통한 추세선을 이용해 피치와 에너지에 대한 2차 다항식계수로 구성하였다. 본 논문은 목표패턴에 맞는 신경망을 학습시켜 좋은 결과를 얻었다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.4
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• pp.363-368
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• 2012

The result of the line simplification algorithm varies with the choice of algorithms, the change in tolerance and the selection of target objects. Three of the algorithms used in this study are Sleeve-fitting, Visvalingam-Whyatt, and Bend-simplify. They were applied to the three kinds of objects which were buildings, rivers, and roads with the five degrees of the tolerance. Through this experiments the vector displacement, the areal displacement, and the angular displacement were measured and the qualitative analysis was performed with the trend line of the errors. The experimental results show that errors were differ from tolerance values, and characteristics of line simplification algorithms based on changes of tolerance were understood.

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.208-212
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• 2002

통신기술의 발달에 따라 기존의 통신망은 TP 기반의 NGN 구조로 통합이 추진되고 있으며, 서비스 형태도 음성주도형 서비스에서 음성과 데이터가 혼합된 멀티미디어형 서비스로 전환되는 추세이다. 또한 기존 PSTN 서비스를 인터넷기반으로 대체하는 인터넷전화 서비스가 출현하게 되었다. 인터넷전화 서비스는 VoIP 관련 번호 제도가 체계적으로 도입되고 사업자 역무가 구체화될 경우 본격적인 활성화 단계에 진입할 것으로 예상된다. 기업측면에서는 통신 요금을 절감하고 음성과 데이터를 통합하여 사용할 수 있는 사설망 구축을 적극적으로 도입하거나 활용을 검토하고 있는 추세이며 개인 고객들도 향후 IP 기반의 유무선 인터넷전화 서비스를 많이 활용하게 될 것이다. 결국 ITSP와 사설기업망이 많이 생겨나게 되고, 이러한 환경에서는 ITSP(Internet Telephony Service Provider)와 사설 기업망 가입자들은 모든 타사업자 (ITSP, 무선통신사업자. PSTN 사업자, 사설 기업망 등)들간 통신을 위하여 협약을 체결하고, 호 라우팅을 위한 정보를 유지하고 과금 정산 기능을 지원하여야 하는 문제점이 있다. 이를 위한 방안으로서 사업자간 정산 시스템을 중심으로 ITSP와 사설기업망 가입자를 연동하도록 구성할 수 있다. 프로토콜로서는 ETSI 표준 프로토콜 OSP을 사용하도록 한다. 본 고에서는 사업자간 정산 시스템(OSPs : OSP 서버)을 통한 ITSP와 사설 VoIP 망들간의 호 서비스 연동 방안을 제시하였다.

• KIEAE Journal
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• v.16 no.6
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• pp.129-134
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• 2016

Today, natural ventilation systems are widely applied in multi-family housing. However, studies using the wind data trend line of the blower door test are insufficient. Purpose: Through this study, we will propose a computational method about ventilation performance of natural ventilation systems by conducting blower door test. Method: First, we sealed the gaps between the main systems including the natural ventilation system and conducted the blower door test. Next, the natural ventilation system was opened, the blower door test was conducted, and the difference in air flow rate between when closed and when opened was checked. Blower door test was carried out with a pressure difference of 50 Pa. Result: Therefore, the ventilation performance of the natural ventilation system was checked by drawing a trend line using the data to calculate the air flow rate at 2 Pa of the natural ventilation equipment standard pressure difference.