• Journal of radiological science and technology
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• v.32 no.2
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• pp.213-218
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• 2009

A theoretical investigation has been carried out on how the energy width of the excited state of the nuclei is modulated when the $\gamma$-ray source is placed between two gold plates, at the center of the gold cylinder or the sphere. The width of the 81-keV level of $^{133}Cs$ is shown to become narrower by 3.7% at 4.2 K by reabsorption of $\gamma$ rays scattered backward from the parallel plates which are made of a 0.05-cm-thick, 3-cm-radius gold plates and separated from each other by 1.0 mm. With a 0.05-cm-thick, 5-cm-long, 1.0-mm-radius gold cylinder, we found that a width became narrower by 6.5%. In addition, when the nuclei is located in a spherical reflector of 1.0 mm in radius made of gold with a thickness of 0.5 mm. the level width is reduced by about 18.2% at a temperature 4.2 K. The results of this study indicates that the life-time of energy level was prolonged.

• Journal of radiological science and technology
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• v.30 no.3
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• pp.245-250
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• 2007

This research measured the shielding rates of apron 0.25 and 0.5 mmPb for X-ray energy in diagnosis radiation system and gamma-ray energy of $^{99m}Tc$-MDP and $^{18}F$-FDG. X-ray energies were measured on effective energy of $26.2{\sim}45.6\;keV$ when additional filtering plate of 0, 2 mmAl is used within the range of tube voltage $40{\sim}120\;kVp$, and at this time, apron 0.5 mmPb has shown about 5.5% of increase in its shielding rate over 0.25 mmPb at the highest quality. Besides, the aprons of the two types have shown high shielding rate of over 90% for direct X-ray and spatial dose rate. And, in case 0.25 and 0.5 mmPb aprons were used at 140keV of $^{99m}Tc$-MDP, the shielding effects were between 30 and 53%, and at high energy of 511 keV, $^{18}F$-FDG, the shielding effects of apron, $1.3{\sim}3.6%$, were very small.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.3
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• pp.199-209
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• 2021

Alternative methods of rock cutting have been introduced to substitute and to improve the traditional mechanical rock excavation methods (e.g., TBM and roadheader). Undercutting methods have been recently studied in some countries. In undercutting, several additional cutting parameters are involved in its cutting process compared to the traditional rock-cutting. As a fundamental study, this paper introduces the concept of undercutting method with actuated disc, lab-scaled testing system, and testing procedures of undercutting by the system. Also, we present the calculation methods of cutter forces and specific energy, and discuss the results of undercutting tests compared to those of traditional rock-cutting methods.

• Journal of the HCI Society of Korea
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• v.5 no.2
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• pp.7-14
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• 2010

Urban Data collected through Sensor Network is becoming crucial to understand and analyse a city. Thus, the Ubiquitous Sensor Network builds the foundation of the u-City development. This research aims to develop an energy monitoring application with an intuitive visualization environment which integrates energy usage information on top of urban geospatial information. Such a system will be able to facilitate effective energy supply plan at the early stages of urban planning, and eventually to encourage citizens to conserve energy by giving them real time monitoring information in an easy to understand visual environment. The system provides multiple layers of energy-related information coupled with the geospatial information layer in order to accommodate multiple viewpoints. On the other hand, the system provides logical Level of Detail control based on urban spatial information hierarchy. We defined the system concept and functions, and designed the data structure and the methods of information visualization. This paper presents the visualization methods, data structure, interactions scenarios which combines spacial information, E-GIS data and the energy related sensor data. Furthermore this research tries to introduce the concept of Social Sensor Networking to enhance the monitoring quality.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.367-369
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• 2014

대한민국에 근대적인 항로표지가 처음으로 개설된 이래 지난 2003년에는 대한민국 등대 100주년을 맞이하여 '유인등대 해양문화공간 조성계획'을 수립하고 유인등대 시설보완 및 개방, 등대 박물관 확장 개관 등을 실시하였다. 이러한 다각도의 노력은 폭발적인 성과를 거두어 2001년 한 해 동안 유인등대를 다녀간 방문객이 공식적으로 기록된 것만 300만 명이 넘게 되었다. 이후 대한민국의 등대는 40여 개의 유인등대와 60여 개의 무인등대가 널리 알려지게 되었고 문화적 가치를 인정받아 현재 23개의 등대가 등대문화유산으로 지정되었으며 지속적으로 발굴하고 있다. 대한민국의 등대가 많은 국민들의 관심 속에서 방문객이 지속적으로 늘어나면서 특히 유인등대는 해양문화공간으로서의 기능이 요구되었고 향후로도 더욱 가속화될 전망이다. 이러한 맥락에서 본 연구는 대한민국 유인등대의 친수문화적 특성을 체계적으로 살펴보고 그에 따라 해양문화공간의 조성 방향을 적절하게 설정할 수 있도록 하기 위한 기본적인 지침을 설정하는 것을 목적으로 한다.

• Journal of the Korean Chemical Society
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• v.23 no.1
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• pp.15-19
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• 1979

The new concept of the Bonding and Antibonding Regions in the transition density space is developed from the Integral Hellmann-Feynman Theorem and the positive definiteness of the transition density. The unility of this concept is fully demonstrated for H2 system. It is expected that the nature of the electronic perturbation energy due to the change of nuclear configuration can be successfully understood by using this concept. Properties of the transition density is briefly discussed.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.3
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• pp.148-157
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• 2012

Recently, people are getting more interested in green energy resource and environment friendly energy resource due to the lack of energy and global warming. This study produced a solar energy resource map using LiDAR(Light Detection And Ranging) data to check if it is utilized for spatial information technology and solar energy sectors that people pay more attentions to as new recycling energy. This study assigned Ulleungdo(Island) located in Gyeongsangbuk-do as a target area. This study created the contour line with 1 meter by newly photographing LiDAR and data processing. And using this contour line, this study built DEM(Digital Elevation Model) data with 1 meter. The incidence range depending on the altitude and azimuth of sun using DEM data is used to evaluate solar energy resource. This is expected to suggest an accurate method to evaluate more reliable and more precise information of new recycling energy resource by producing solar energy resource map based on accurate and precise spatial resolution data with 1 meter level.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.65-65
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• 2017

상수관망 시스템(Water Distribution System, WDS)은 원활한 용수 공급을 위해 구축된 사회기반시설물로써, 물 공급절차에 따라 그 구성요소를 공급원, 공급 경로, 수요지 등의 범주로 구분할 수 있다. 원활한 물 공급이란 수요지에서 요구하는 수량과 압력 수준을 충족시키는 것을 의미하며, 따라서 상수관망의 용수공급능력은 요구 수량 및 압력과 실제 공급 결과를 비교함으로써 가늠할 수 있다. 과거에는 두 가지 기준을 별도로 산정하여 이를 평가하였으나, 유량과 압력을 함께 고려할 수 있는 에너지 기반의 평가 방법이 제시되면서 시스템 내 에너지 분포를 정량화하여 시스템의 용수공급능력을 평가하는 연구가 주목받고 있다. 세계적으로 많은 연구자들은 시스템 내 에너지 흐름 상태를 정량화함으로써 다양한 형태의 상수관망의 신뢰도지수(Reliability Index)를 제안한 바 있다. 이 때, 대부분의 신뢰도 지수 연구에서는 수요지에 공급된 에너지를 기본적으로 유지해야 하는 최소요구 에너지(Required Energy)와 비상 상황에 대응하기 위한 잉여 에너지(Surplus Energy)로 구분하고 있으며, 잉여 에너지를 상수관망의 공급 안정성을 나타내는 핵심 요소로 활용하고 있다. 확보된 잉여 에너지는 비상시 최소요구 에너지를 대체하는 개념에서 복원력으로 표현되어, 잘 알려진 Resilience Index(RI)를 비롯해 많은 복원력 지수가 존재한다. 본 연구에서는 복원력 지수를 포함한 세 가지의 신뢰도 지수를 적용하여 상수관망의 용수공급 상황 변화에 따른 시스템의 안정성을 분석하였다. 특히, 절점별 복원력 지수를 산정하고 그 분포를 공간적으로 도시하여 파악함으로써, 비상시 효율적인 운영을 위한 판단기준으로써 신뢰도 지수를 폭 넓게 활용할 수 있음을 제시하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.56-65
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• 2005

A dynamic analysis method that freezes a time domain by discretization and solves the spatial propagation equation has a unique feature that provides a degree of freedom on spatial domain compared with the space discretization or space-time discretization finite element method. Using this feature, the time finite element analysis can be effectively applied to optimize the spatial characteristics of distributed type actuators. In this research, the time domain finite element method was used to discretize the model. A state variable vector was used in the discretization to include arbitrary initial conditions. A performance index was proposed on spatial domain to consider both potential and vibrational energy, so that the resulting shape of the distributed actuator was optimized for dynamic control of the structure. It is assumed that the structure satisfies the final rest condition using the realizable control scheme although the initial disturbance can affect the system response. Both equations on states and costates were derived based on the selected performance index and structural model. Ricatti matrix differential equations on state and costate variables were derived by the reconfiguration of the sub-matrices and application of time/space boundary conditions, and finally optimal actuator distribution was obtained. Numerical simulation results validated the proposed actuator shape optimization scheme.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.285-292
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• 1999

The design parameter of the reactor vessel insulation for the Korea Standard Power Plant has been studied numerically. The heat loss from the reactor vessel through the insulation is analysed by using the computational fluid dynamics code, FLUENT. Parametric study has been performed on the air gap width between the reactor vessel wall and the inner surface of the insulation, and on the insulation thickness. Also evaluated is the performance degradation due to the chimney effect caused by gaps between the panels during the installation of the insulation system. From the analysis results, the optimal air gap width and the optimal insulation thickness are obtained.