• Journal of Radiation Protection and Research
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• v.28 no.1
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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.

• Particle and aerosol research
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• v.9 no.2
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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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• no.1
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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.

• Knowledge Management Research
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• v.19 no.2
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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.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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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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• v.4 no.3
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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.

• Journal of IKEEE
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• v.25 no.2
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• pp.291-301
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• 2021

OPC UA at the control and field level does not provide enough performance to replace the field bus. The OPC Foundation aims for a real-time and connection-less mechanism, and has added the OPC UA publish-subscribe model, a new specification that supports broker functions such as MQTT and AMQP, as the OPC UA Part 14 standard. This paper is about a gateway for interoperability between OPC UA publisher with the addition of OPC UA Part14 standard and DDS subscribers. Raspberry Pi 4 is used for the gateway proposed in this paper, and OpenDDS, an open source, is used for DDS. OPC UA publish-subscribe module used A-Open62541 publish-subscribe module, which additionally implements functions not provided by the corresponding source based on Open62541 publish-subscribe open source.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.279-285
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• 1989

Central axis depth dose data for 6 MV X-rays, including tissue maximum ratios, were measured for wedge fields according to Tatcher's equation. In wedge fields, the differences in magnitude which increased with depth, field size, and wedge thickness increased when compared with the corresponding open field data. However, phantom scatter correction factors for wedge fields differed less than $1\%$ from the corresponding open field factors. The differences in central axis percent depth dose between two types of fields indicated beam hardening by the wedge filter The deviation of percent depth doses and scatter correction factors between the effective wedge field and the nominal wedge field at same angle was negligible. The differences were less than $3.20\%$ between the nominal or effective wedge fields and the open fields for percent depth doses to the depth 7cm in $6cm{\times}6cm$ field. For larger $(10cm{\times}10cm)$ field size, however, the deviation of percnet depth doses between the nominal or effective wedge fields and the open fields were greater-dosimetric errors were $3.56\%$ at depth 7cm and nearly $5.30\%$ at 12cm. We suggest that the percent depth doses of individual wedge and wedge transmission factors should be considered for the dose calculation or monitor setting in the treatment of deep seated tumor.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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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'.

• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.93-101
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• 2012

In the field of urban planning and disaster prevention, various geographical information systems (GIS) and design softwares have been in use. Recently urban planners and disaster managing officials face new challenges, as three dimensional GIS, web environment, and smart phone app are rapidly developed. Technical progress in open API and mashup opens a possibility of making the citizen participation-based smart phone applications in the field of urban planning and disaster prevention. Our suggested smart phone applications will have technical, economic, and administrative impacts on the society in general; and play an effective role in developing U-City, U-health, and disaster prevention.