• Journal of Radiation Protection and Research
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• 제28권1호
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• pp.59-63
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• 2003

Purpose : Measurement of transmission dose is useful for in vivo dosimetry of QA purpose. The objective of this study is to develope an algorithm for estimation of tumor dose using measured transmission dose for open radiation field. Materials and Methods : Transmission dose was measured with various field size (FS), phantom thickness (Tp), and phantom chamber distance (PCD) with a acrylic phantom for 6 MV and 10 MV X-ray Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 cc Farmer type ion chamber. Using measured data and regression analysis, an algorithm was developed for estimation of expected reading of transmission dose. Accuracy of the algorithm was tested with flat solid phantom with various settings. Results : The algorithm consisted of quadratic function of log(A/P) (where A/P is area-perimeter ratio) and tertiary function of PCD. The algorithm could estimate dose with very high accuracy for open square field, with errors within ${\pm}0.5%$. For elongated radiation field, the errors were limited to ${\pm}1.0%$. Conclusion : The developed algorithm can accurately estimate the transmission dose in open radiation fields with various treatment settings.

• 한국입자에어로졸학회지
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• 제9권2호
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• pp.103-110
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• 2013

The electrostatic precipitator (ESP) has been used for degrading atmospheric pollutants. These devices induce the electrical forces to facilitate the removal of particulate pollutants. The ions travel from the high voltage electrode to the grounded electrode by Coulomb force induced by the electric field when a high voltage is applied between two electrodes. The ions collide with gas molecules and exchange momentum with each other thus inducing fluid motion, electrohydrodynamic (EHD) flow. In this study, for the simulation of electric field and EHD flow in ESPs, an open source EHD solver, "espFoam", has been developed using open source CFD toolbox, OpenFOAM(R) (Open Field Operation and Manipulation). The electric potential distribution and ionic space charge density distribution were obtained with the developed solver, and validated with experimental results in the literature. The comparison results showed good agreement. Turbulence model is also incorporated to simulate turbulent flow; hence the developed solver can analyze laminar and turbulent flow. In distributions of electric potential and space charge, the distributions become distorted and asymmetric as the flow velocity increases. The effect of electrical drift flow was investigated for different flow velocities and the secondary flow in a flow of low velocity is successfully predicted.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• 제1호
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• pp.150-158
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• 2001

Maintenance open spaces and community development in large scale housing development is one of the most important issues. We(UDC) established a resident participation activity for maintenance and use open space with community development in Hachioji New Town from 1997. The purpose of this study is to establish resident participation activities for maintenance and use open space with community development in Hajichioji New Town, and to clarify the characteristics and to on sider about efficiency of the activity. We established Minamino Shizen-Juku as a methodology for maintenance and use open spaces at the same time Hachioji New Town was opened in 1997. The activity has continued by now in 2001. We conducted questionnaire survey to make sure efficiency and characteristics of the activity past three years. Minamino Shizen-Juku (nature friendly lessons) is a resident participation activity in Hachioji New Town. It was established in 1997 as soon as the new town was opened, this year is fifth since it was started. It has three objects. 1)Maintenance and use woody environment, 2) Community development, 3) Continuation and renewal native culture. And it has general course, three special courses and one extra course were established in the activity. 1) General course is an activity participated all of member. It's included farming experience in the native field and seasonal events. 2) Rice growing and woods maintenance course is rice growing and wild wood maintenance in the park as a series of annual farming activities. 3) Benefaction from farm course is started from planting spring vegetable at Mizukoshi(Leader of Minamino Shezen-Juku)'s field. There is the number of participant limit because of the area of the field. 4) Watching nature course is watching seasonal wild flowers, trees, animals and plants to know about native nature. 5) Extra program is programmed to know about native history and tradition. It's planned including participant's ideas. Not member can participate in this course too.

• 지식경영연구
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• 제19권2호
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• pp.133-150
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• 2018

To cope with the rapid changes in the corporate environment, the creation of innovative output through various forms of collaboration have been discussed. For open collaborations, contributors who distribute to various countries and cultures are able to share knowledge via the internet without physical rewards or responsibilities. In this study, we focused on the open source software project, which is a representative open collaboration. We investigated the factors that affect the knowledge contribution of developers of various countries within the open collaboration platform. Specifically, we investigated the open collaborative nature of multi-culture developers by dividing cultures according to collectivism and individualism. We collected data on 26,604 developers using a python based web crawler for GitHub which is an open source software development platform, and conducted cross-cultural study. This paper contributes to the field of knowledge management by suggesting various impacts of antecedents such as hireability, and information exposure on knowledge sharing according to culture.

• 천문학회보
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• 제44권1호
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• pp.84.1-84.1
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• 2019

722 open clusters in the Sim open cluster catalogue show the outermost structure of open clusters. The catalogue is based on the proper motion and parallax of the stars. These results reveal the hidden structures of weak membership signals in the field star contamination. It contains the tidal tails, flattened structure along the galactic plane, interacting double clusters and very poor and spread clusters. We will show these interesting structures.

• Journal of Magnetics
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• 제4권3호
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• pp.98-101
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• 1999

In this work we htave constructed an under water sonar transducer using Terfenol-D rod employing open magnetic circuit. Normally Sonar transducer using Terfenol-D was designed under closed magnetic flux return path, and permanent magnet for dc bias marnetic field, but high magnetic field should be applied to the transducer coil for high sound power and it brings temperature increase inside of the transducer. To improve this heat dissipation problem, we have designed an open magnetic circuit type transducer and we can get 200 dB (re. 1 Pa @ 1m) sound power for the input power of 650 VA.

• 전기전자학회논문지
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• 제25권2호
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• pp.291-301
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• 2021

제어 및 필드 레벨에서의 OPC UA는 필드 버스를 대체할 만큼의 충분한 성능을 제공하지 못한다. OPC 협회는 실시간 및 비연결 메커니즘을 지향하고, MQTT나 AMQP와 같이 브로커 기능을 지원하는 새로운 사양인 OPC UA 발행-구독 모델을 OPC UA Part14 표준으로 추가하였다. 본 논문은 OPC UA Part14 표준을 추가한 OPC UA 발행자와 DDS 구독자 간에 상호운용성을 위한 게이트웨이에 관한 내용이다. 본 논문에서 제안한 게이트웨이는 라즈베리파이 4를 사용하였으며, DDS는 오픈 소스인 OpenDDS를 사용하였다. OPC UA 발행-구독 모듈은 Open62541 발행-구독 오픈 소스를 기반으로 해당 소스에서 제공하지 않는 기능을 추가 구현한 것인 A-Open62541 발행-구독 모듈을 사용하였다.

• Radiation Oncology Journal
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• 제7권2호
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• pp.279-285
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• 1989

Tatcher식에 의하여 조직최대선량비와 깊이선량을 6MV X-선의 중심축상에서 측정하였다. 쐐기형 조사야에 있어서 깊이, 조사야 및 쐐기의 두께 등이 증가할수록 깊이선량은 개방 조사야에 비하여 크기가 증가하였다. 그러나 쐐기형 조사야에 있어서 조직산란보정 계수는 개방 조사야에 비하여 그 차이가 $1\%$ 미만이었다. 두 조사야에 있어서 중심축상의 깊이선량백분률의 차이가 발생하는 것은 쐐기에 의해서 X-선이 강화됨을 의미한다. 같은 각도의 쇄기에서 깊이선량백분률과 산란보정계수의 명목쐐기형 조사야와 유효쐐기형 조사야사이의 차이는 없었다. 개방조사야에서 조사야 $6cm{\times}6cm$, 깊이 7cm의 깊이선량백분률은 명목 또는 유효쐐기형 조사야 보다 $3.26\%$가 더 컸다. 그러나 조사야 $(10cm{\times}10cm)$가 커질수록 깊이선량백분률의 차이는 명목 또는 유효쐐기형 조사야보다 더 증가하였다-선량계측차이는 깊이 7cm에서 $3.56\%$, 12cm에서는 $5.30\%$였다 그러므로 심부종양치료시 선량의 계산이나 모니터세팅은 각 쐐기의 깊이 백분선량률과 투과율을 사용하여야 오차를 줄일 수 있을 것으로 사료된다.

• Journal of Advanced Marine Engineering and Technology
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• 제32권6호
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• pp.989-996
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• 2008

Recently, a few types of fish-cage in open sea are researched. This fish-cage has to operate monitoring system for keeping an optimum living condition for fish. The most efficient monitoring system is WVMS(Wireless Vision Monitoring System) for fish-cage in open sea. WVMS should be able to transmit video signal and communicate with each controller. So. it needs to be based on WLAN(Wireless LAN) which has characteristic of higher transfer-rate, In this paper, we propose a structure of WVMS using WLAN equipments for maritime environment and prove its effectiveness. We present the propagation loss model of WVMS's communication channel. measured by field test, and discuss its validity compared with the predictive value based on the Friss propagation model and Plane earth reflection model. We present the number of frames that is received from WLAN modem connecting with underwater-camera in field test spots. As a result, we confirmed that proposed WVMS is suitable for maritime environment and it is possible to be applied to fish-cage in open sea on 'seogwipo'.

• 한국컴퓨터정보학회논문지
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• 제17권5호
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• pp.93-101
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• 2012

도시계획이나 재난방재와 관련하여 지리정보시스템과 설계용 소프트웨어를 중심으로 한 다양한 소프트웨어들이 활용되고 있다. 그러나, 최근의 스마트폰 애플리케이션을 중심으로 한 모바일 환경의 변화와 3차원 지리정보시스템의 발전, 그리고 web 환경의 변화는 도시계획이나 재난방재 분야에 새로운 변화를 요구하고 있다. 특별히 Open API와 Mashup의 성장과 발전은 도시계획이나 재난방재 분야에 시민참여형 스마트폰 애플리케이션의 가능성을 넓혀주고 있다. 본 연구에서 제안하는 시민 참여형 스마트폰 애플리케이션 개발은 기술적, 경제적 및 행정적 파급효과를 가져올 뿐 아니라, 최근 활발히 건설되고 있는 U-City, U-health, 그리고 재난방재에 효과적인 역할을 할 것을 기대할 수 있다.