• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2008년도 제7회 추계학술대회 및 정기총회
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• pp.301-308
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• 2008

• 대한조선학회논문집
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• 제54권1호
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• pp.63-70
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• 2017

Release of hazardous and flammable gas is a significant contributor to risk. The ignition of flammable gas clouds can lead to explosion accidents in the offshore installations. A gas detector, which is one of active protect systems, brings the module into a safe state through emergency shut down processes and reduces the damage by eliminating the dangerous releases. It is critical to understand the gas release, the wind field, and the complex geometry of installations to determine gas detector placement. In this paper, the Gas detector Location Index (GLI) which is a novel index for optimal detector location determination to efficiently prevent explosion accident using probabilistic approach.

• 한국ITS학회 논문지
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• 제8권5호
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• pp.26-37
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• 2009

본 연구에서는 USN 환경하에서 다수 개의 지점교통센서를 신호교차로의 접근로에 설치되어 운전자 안전서비스를 제공할 경우 딜레마구간 검지를 위한 센서의 배치 방법에 대하여 다룬다. 교통 신호가 녹색-황색-적색으로 변동되는 시점에서 딜레마구간에 존재하는 위험차량을 검지하는 시스템에서, 센서의 배치 간격과 초기 위치를 확인하기 위해 미시적 시뮬레이션인 VISSIM을 이용하여 평가하였다. VISSIM에 지점검지기를 다수 개 설치하여 유입교통량의 변화, 설계속도의 변화, 운전자 인지반응시간의 변화를 수행하였다. 그 결과 지점교통센서는 20~27m의 간격으로, 도로의 설계속도에 따라 초기 센서의 위치를 변화하여 설치할 필요성이 있음을 알 수 있었다. 또한 교통량의 변화에 따라 센서의 딜레마구간 검지추세가 다름을 알 수 있었다. 본 연구로 미시적 교통시뮬레이션 기반으로 지점교통센서의 배치를 평가하는 방법의 유용성을 확인할 수 있었고, 향후 USN 서비스의 실현에 있어 기초 자료로 사용될 수 있음을 알 수 있었다.

• 한국안전학회지
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• 제32권5호
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• pp.168-178
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• 2017

In order to prevent major and chemical accidents, some of the plants which would like to install and operate hazard chemicals handling facilities must submit Off-site Consequence Analysis due to recent arisen leak accidents since 2015. A lot of chemical industrials choose gas detectors as mitigation equipment to early detect gas vapor. The way of placement of gas detectors has two methods; Code-based Design(CBD) and Performance-based Design. The CBD has principles for gas detectors to be installed with consideration for the place that is expected to accumulate gas, and the leak locations according to legal standards and technical guidelines, and has a possibility to be unable to detect by these rules to locate gas detectors by vapor density information. The PBD has two methods; a Geographic Method and Scenario based Method. The Scenario-based Method has been suggested to make up for the Geographic Coverage Method. This Scenario-based Method draw the best optimum placement of gas detectors by considering leak locations, leak speed information, leak directions and etc. However, the domestic placement guidelines just refers to the CBD. Therefore, this study is to compare existing placement location of gas detectors by the domestic CBD with placement locations, coverages and the number of gas detectors in accordance with the Scenario-based Method. Also this study has measures for early detecting interest of Vapor Cloud and suitable placement of gas detectors to prevent chemical accidents. The Phast software was selected to simulate vapor cloud dispersion to predict the consequence. There are two cases; an accident hole size of leak(8 mm) from API which is the highst accident hole size less than 24.5 mm, and a normal leak hole size from KOSHA Guide (1.8 mm). Detect3D was also selected to locate gas detectors efficiently and compare CBD results and PBD results. Currently, domestic methods of gas detectors do not consider any risk, but just depend on domestic code methods which lead to placement of gas detectors not to make personnels recognize tolerable or intolerable risks. The results of the Scenario-based Method, however, analyze the leak estimated range by simulating leak dispersion, and then it is able to tell tolerable risks. Thus it is considered that individuals will be able to place gas detectors reasonably by making objectives and roles flexibly according to situations in a specific plant.

• 대한안전경영과학회지
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• 제16권4호
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• pp.379-389
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• 2014

Fire detectors are designed to minimize loss of life from a fire alarm system as an alarm to help evacuate more quickly until the completion of the evacuation alarm should be continued. the purpose of such alarms in order to achieve the characteristic fire heat release rate reaches a certain level, or when a certain time has elapsed, when the heat detector is to be alarms to answer. Requires a quick response, it is desirable to install the sensor as much as possible, but taking into account the cost of installation problems by engineering approach to minimize the quantity and rapidity of detection capability should be increased. In order to increase the rapidity of fire detectors in a room according to the height of the sensing period is to be maintained the optimum distance of the fire detector detects characteristics should be considered. Differential spot-type heat detectors installed domestic basis, depending on the type of sensor that can detect one sensor area is limited and less than 4m ceiling height regulations and simply double the number in excess of 4m and intended to be installed.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.799-806
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• 2012

In recent years, a new algorithm has been introduced to perform the regional overpower protection (ROP) detector layout optimization for $CANDU^{(R)}$ reactors. This algorithm is called DETPLASA. This algorithm has been shown to successfully come up with a detector layout which meets the target trip set point (TSP) value. Knowing that these ROP detectors are placed in a number of safety channels, one expects that there is an optimal placement of the candidate detectors into these channels. The objective of the present paper is to show that a slight improvement to the TSP value can be realized by optimizing the channelization of these ROP detectors. Depending on the size of the ROP system, based on numerical experiments performed in this study, the range of additional TSP improvement is from 0.16%FP (full power) to 0.56%FP.

• 방사선산업학회지
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• 제11권3호
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• pp.157-165
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• 2017

In this paper, we calculate the light photons collection efficiency of large-volume plastic scintillation detector mainly used for radiation portal monitor (RPM). A Monte Carlo light photon transport code, DETECT2000, were used to quantitatively evaluate light collection efficiency of plastic scintillation detector. DETECT2000 calculated the placement of light collection efficiency based on the energy spectrum. We calculated the light collection efficiency relative to the position of the energy spectrum that proportional to the placement of the source. The $850{\times}285{\times}65mm^3$ size of polyvinyl toluene (PVT) scintillator was used for measurements. Through DETECT2000 simulation, the light collection efficiency of $5{\times}5$ arrays were calculated and verification was performed by comparing with experimentally measured. And then, the corrected MCNP simulation by applying the light collection efficiency in $21{\times}13$ arrays was compared and analyzed. Comparing the Monte Carlo simulation with measured results, it shows an average difference of 10.1% in $5{\times}5$ arrays. Particularly, about twice of the difference was found in the edge of first column, which coupled with PMT. In whole $5{\times}5$ array, the overall ratio was the same except for the first column. And then comparing the energy spectra of the $21{\times}13$ array with and without the light collection efficiency, it shows a difference of 6.69% in Compton edge area. The DETECT2000 based light collection efficiency simulation showed well agreement with the point source experiment. And comparing with measured energy spectra, we could compare the differences according to whether or not the light collection efficiency was applied. As a results, it is possible to increase the accuracy and reliability of Monte Carlo simulation results by pre-calculating the light collection efficiency according to the PVT geometry by using the DETECT2000.

• 한국화재소방학회논문지
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• 제24권1호
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• pp.15-23
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• 2010

현재의 화재안전기준에서 규정하는 화재감지기의 배치방법은 면적에 따라 규정된 숫자를 적정하게 배치하는 수준이다. 이 기준은 과학적인 근거는 가지고 있지 못하다. 외국의 기준을 도입하여 그에 따라서 설치하고 있을 뿐이다. 소방시설을 설계하는 방법에는 화재안전기준과 같이 명문화 된 규정에 따르는 규범위주설계(Prescriptive-based)와 화재역학, 구조역학, 재료역학, 유체역학, 열역학 등 공학적 지식을 바탕으로 하는 성능위주설계(Performance-based design)가 있다. 현재로서는 성능위주설계가 활성화 되지 않았지만, 최근 소방시설공사업법은 성능위주설계방법을 이용하여 소방시설을 설계 할 수 있도록 개정('05. 8. 4)되었으며 그 시행령('07, 1. 24)에서 성능위주설계를 적용할 특정소방대상물의 범위를 정하고 있다. 이러한 시점에서 자동화재탐지설비의 화재감지기를 최적의 위치 및 거리에 설치하기 위하여 그에 대한 공식의 도입과 공식을 Software로 계산할 수 있도록 시뮬레이터를 제작하여 계산하고 규범위주설계에 따라 배치한 화재감지기의 상태와 비교 분석하며 향후 성능위주설계 방법으로서 정착시키기 위하여 연구를 시도하였다.

• Imaging Science in Dentistry
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• 제48권3호
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• pp.167-176
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• 2018

Purpose: In the age of X-ray computed tomography (CT) and digital volume tomography (DVT), with their outstanding post-processing capabilities, indications for planar radiography for the study of the dentition of ancient Egyptian mummies may easily be overlooked. In this article, the advantages and limitations of different approaches and projections are discussed for planar oral and maxillofacial radiography using portable digital X-ray equipment during archaeological excavations. Furthermore, recommendations are provided regarding projections and sample positioning in this context. Materials and Methods: A total of 55 specimens, including 19 skeletonized mandibles, 14 skeletonized skulls, 18 separate mummified heads, and 4 partially preserved mummies were imaged using portable digital X-ray equipment in the course of archaeological excavations led by the University of Basel in the Valley of the Kings between 2009 and 2012. Images were evaluated by 2 authors with regard to the visibility of diagnostically relevant dental structures using a 4-point grading system(Likert scale). Results: Overall, the visibility of diagnostically relevant dental structures was rated highest by both authors on X-ray images acquired using a dental detector. The tube-shift technique in the lateral projections of mandibular dentition achieved the second-best rating, and lateral projections achieved the third-best rating. Conclusion: Conventional planar digital X-ray imaging, due to its ubiquity, remains an excellent method-and often the only practicable one-for examining the skulls and teeth of ancient Egyptian mummies under field conditions. Radiographic images of excellent diagnostic quality can be obtained, if an appropriate methodology regarding the selected projections and sample placement is followed.

• 방송공학회논문지
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• 제25권6호
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• pp.882-897
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• 2020

최근 Panorama와 360° 영상이 대표되는 몰입형 미디어 콘텐츠의 활용이 증가하고 있다. 일반적인 카메라 한 대를 통해서 해당 콘텐츠를 생성하기에는 시야각이 제한되기 때문에, 다수의 카메라로 촬영한 영상을 넓은 시야각을 갖는 하나의 영상으로 합성하는 영상 스티칭이 주로 사용되고 있다. 그러나 촬영하는 카메라 간의 시차(Parallax)가 크다면 스티칭 영상에서 시차 왜곡이 발생할 수 있고, 이는 사용자의 콘텐츠 몰입을 제한하기 때문에 시차 왜곡을 극복할 수 있는 영상 스티칭 기술이 필요하다. 시차 왜곡을 극복하기 위한 기존의 Seam Optimization 기반 영상 스티칭 방법은 사물의 위치 정보를 반영하기 위하여 에너지 함수나 객체 세그먼트 정보를 활용하고 있지만, 초기 Seam 생성 위치, 배경 정보, 사물 검출기의 성능 그리고 사물의 배치 등의 제한 사항으로 인해 기술의 적용이 제한될 수 있다. 이에 본 논문에서는 딥러닝 기반 사물 검출을 활용하여 사물의 종류에 따라 다르게 설정한 가중치 값을 시각적 인지 에너지 값에 더함으로써, 기존 기술의 제한 사항을 극복할 수 있는 영상 스티칭 방법을 제안하고자 한다.