• Radiation Oncology Journal
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• v.16 no.1
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• pp.71-79
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• 1998

Purpose : The objective of this study is to introduce our installation of a non-commercial 3D Planning system, Plunc and confirm it's clinical applicability in various treatment situations. Materials and Methods : We obtained source codes of Plunc, offered by University of North Carolina and installed them on a Pentium Pro 200MHz (128MB RAM, Millenium VGA) with Linux operating system. To examine accuracy of dose distributions calculated by Plunc, we input beam data of 6MV Photon of our linear accelerator(Siemens MXE 6740) including tissue-maximum ratio, scatter-maximum ratio, attenuation coefficients and shapes of wedge filters. After then, we compared values of dose distributions(Percent depth dose; PDD, dose profiles with and without wedge filters, oblique incident beam, and dose distributions under air-gap) calculated by Plunc with measured values. Results : Plunc operated in almost real time except spending about 10 seconds in full volume dose distribution and dose-volume histogram(DVH) on the PC described above. As compared with measurements for irradiations of 90-cm 550 and 10-cm depth isocenter, the PDD curves calculated by Plunc did not exceed $1\%$ of inaccuracies except buildup region. For dose profiles with and without wedge filter, the calculated ones are accurate within $2\%$ except low-dose region outside irradiations where Plunc showed $5\%$ of dose reduction. For the oblique incident beam, it showed a good agreement except low dose region below $30\%$ of isocenter dose. In the case of dose distribution under air-gap, there was $5\%$ errors of the central-axis dose. Conclusion : By comparing photon dose calculations using the Plunc with measurements, we confirmed that Plunc showed acceptable accuracies about $2-5\%$ in typical treatment situations which was comparable to commercial planning systems using correction-based a1gorithms. Plunc does not have a function for electron beam planning up to the present. However, it is possible to implement electron dose calculation modules or more accurate photon dose calculation into the Plunc system. Plunc is shown to be useful to clear many limitations of 2D planning systems in clinics where a commercial 3D planning system is not available.

• Radiation Oncology Journal
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• v.20 no.3
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• pp.283-293
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• 2002

Purpose : A PC based brachytherapy planning system was developed to display dose distributions on simulation images by 2D isodose curve including the dose profiles, dose-volume histogram and 30 dose distributions. Materials and Methods : Brachytherapy dose planning software was developed especially for the Ir-192 source, which had been developed by KAERI as a substitute for the Co-60 source. The dose computation was achieved by searching for a pre-computed dose matrix which was tabulated as a function of radial and axial distance from a source. In the computation process, the effects of the tissue scattering correction factor and anisotropic dose distributions were included. The computed dose distributions were displayed in 2D film image including the profile dose, 3D isodose curves with wire frame forms and dosevolume histogram. Results : The brachytherapy dose plan was initiated by obtaining source positions on the principal plane of the source axis. The dose distributions in tissue were computed on a $200\times200\;(mm^2)$ plane on which the source axis was located at the center of the plane. The point doses along the longitudinal axis of the source were $4.5\~9.0\%$ smaller than those on the radial axis of the plane, due to the anisotropy created by the cylindrical shape of the source. When compared to manual calculation, the point doses showed $1\~5\%$ discrepancies from the benchmarking plan. The 2D dose distributions of different planes were matched to the same administered isodose level in order to analyze the shape of the optimized dose level. The accumulated dose-volume histogram, displayed as a function of the percentage volume of administered minimum dose level, was used to guide the volume analysis. Conclusion : This study evaluated the developed computerized dose planning system of brachytherapy. The dose distribution was displayed on the coronal, sagittal and axial planes with the dose histogram. The accumulated DVH and 3D dose distributions provided by the developed system may be useful tools for dose analysis in comparison with orthogonal dose planning.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.612-616
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• 2007

오랫동안 홍수조절, 용수공급, 전력생산, 레저 활동을 위해 건설된 댐들은 하천이나 호소의 생태적 기능보다는 치수 및 이수기능이 중요시되면서 운영 관리되어 왔다. 하지만 최근 들어 선진국을 중심으로 환경 및 생태의 중요성이 인식되면서 하천생태계 보호를 위한 환경유량 산정이 언급되고 있는데 이는 하천이 동 식물의 서식처로서 적절한 수질뿐만 아니라 수심, 유속, 하상재료, 먹이원, 어류를 보호할 수 있는 휴식 및 은신처 등의 다양한 조건을 제공할 수 있어야 한다고 제시되고 있다. 이들 조건 중 유량(Flow)은 하천에서 생물집단을 구성하는데 있어 물리적 서식조건의 주요한 결정인자로 작용하는데, 댐 하류하천의 자연유량(natural flow)을 변화시키면 생태학적 측면에서 기대치 않던 영향을 야기할 수 있다. 따라서 댐 건설 전 후의 자연유량과 조절유량 사이에서 생태학적 어류조사연구를 통한 차이점을 찾는 것은 매우 중요하다고 볼 수 있다. 본 연구의 최종목적은 수계 내 댐 건설 전 후의 어류군집과 유량 등 수리조건과의 연관성을 분석하여 하천구간별로 어류생태에 적합한 유량을 산정하는 것이다. 조사대상 구간은 금강본류를 대상으로 하되 용담댐과 대청댐을 중심으로 하여 10개 구간을 선정하였고. 과거로부터 2000년도까지와 용담댐 건설후인 $2002{\sim}2004$년도에 조사된 어류생태자료를 활용하였다. 용담댐 상류로부터 대청댐 하류에 이르기까지 전 구간을 대상으로 조사된 자료를 분석한 결과 총 20과 82종이 출현하였고, 이중 종 45종(54.9%)이 잉어과에 해당하며 미꾸리과(6종), 동자개과(4종), 망둑어과(5종)를 제외한 대다수의 분류군(Family)들은 단일 또는 2종으로만 구성되었다. 이들 중 천연기념물 제 259호로 지정되어 법적으로 보호되고 있는 어름치(금강에서 서식한 어름치를 따로 천연기념물 238호로 지정함)를 비롯하여 다묵장어를 포함한 7종의 멸종위기종이 확인되었다. 또한 각시붕어 등 총 29종(39.4%)의 높은 한국고유종 출현과 6종의 외래도입종도 확인되었다. 금강의 중 상류에 해당하는 구역을 포함하는 대청댐 상 하류 구간에서 대청댐 건설 전(1980년 이전)을 포함하는 2000년 이전 조사 자료가 가장 다양한 어류상과 특이어종(멸종위기종 및 한국고유종)을 보였고, 최근자료$(2002{\sim}2004)$를 살펴볼 때 용담댐 상 하류에서보다 대청댐 상 하류에서 멸종위기종(7종$\rightarrow$1종) 및 한국고유종(28종$\rightarrow$16종)의 출현감소와 외래도입종의 출현증가(1종$\rightarrow$6종)와 같은 주요한 어류군집 변화를 보였다. 이는 댐 건설에 따라 주로 계류성 어종을 중심으로 정수역 구간에서 인근 지류로 이동하게 되고 일부는 제한된 서식공간과 하천교란으로 인해 개체군이 극감하거나 일부 소멸된 종이 발생하였을 것으로 사료된다. 실측 유량자료 분석에 의하면 홍수기 최대유량 변화는 크지 않으나, 갈수기 최소유량은 크게 증가한 것을 알 수 있었고, 대다수 어류의 산란기인 봄철(5월, 6월) 최소유량은 증가하였으나, 최대유량은 감소한 것으로 분석되었다. 이러한 변화는 어류생태계에 긍정적인 면과 부정적인 면이 있으며, 향후 이러한 영향을 분석하기 위해 선택어종(Target species)별 생태환경 서식조건을 확인할 수 있는 조사기법 및 자료구축이 절실히 필요한 실정이다.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.29-34
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• 2003

It has been well documented that white egg layers are far more resistant to fowl typhoid than the brown egg layers. In Korea, however, most consumers prefer brown eggs to white ones. Therefore, a study was conducted to Produce fowl typhoid-resistant crossbred layers producing somewhat brown-colored eggs. Several crossbred strains were obtained from crossbreeding white egg lines (W) with brown egg lines (B). These crossbred layers (W${\times}$B) produced eggs with varying degrees of brown-colored shells between the white eggs obtained from W (White) and the brown eggs from B (Brown). Eggs from the peak stage of production were collected and their eggshell color values were measured. The mean eggshell color values of White and Brown were 81.9 and 36.4, respectively. Eggs from the crossbred lines (W${\times}$B) were collected, and their eggshell color values were measured to re-group these eggs according to their color. The mean eggshell color values of Trt-White, Middle, and Trt-Brown were 70, 60, and 50, respectively (Fig. 1). A total of 247 people living in Daejeon area, mainly housewives, took part in this survey. First, they were offered eggs with varying degrees of eggshell color in a paper egg-tray, together with a questionnaire. After they filled out the first questionnaire, they were instructed that the eggshell color has nothing to do with its nutritive value. In the second questionnaire, their preference on both eggshell color and price, i.e., purchasing will, were investigated. In the first questionnaire, the Brown (eggshell color lightness 36.4) were most preferred, and the Trt-white (eggshell color lightness 70) were least preferred. No statistical significance was detected between Brown and Trt-Brown, and White and Trt-White. In the second questionnaire, the trend was the same as in the first. Although no significant difference was found between Trt-Brown and Brown, however, the Trt-Brown were most preferred, surpassing the Brown. In conclusion, regardless of the nutritive values, the Korean consumers prefer brown eggs to white ones, and this trend could be changed gradually through consumer education.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.249-255
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• 2008

The experiment was conducted to determine effect of the mixed herbal medicine for the substitution of antibiotics on the performance of laying hens. Day old hyline 1,500 layer chicks were randomly assigned to 4 treatments. Control were 600 chicks and there were three treatments of each 300 chicks. The 4 treatments were as follows: the mixed herbal medicine 0.1%(T-1), 0.3%(T-2) and 0.5%(T-3) after removed antibiotics on commercial feed and commercial feed( control) from 5th week to 13th week, each treatment was replicated 3 times and from 14th week to 18th week. Each 100 hens of the mixed herbal medicine 0.1%(CT-1), 0.3%(CT-2) and 0.5%(CT-3) were moved to cage. Body weight were measured on 4th, 8th, 13th week and feed intake, mortality were measured on every weeks. Body weight at fourth week, all treatments tended to be higher than control and T-3 statistically was highest(p<0.01). On 8th week, also treatments statistically high and T-1 was highest(p<0.01). But 12th week, there was not significantly different among treatments. Therefore it will be possible that the mixed herbal medicine substitute for antibiotics after vaccination. Mortality was not different between treatment and control overall rearing period. Early laying period($19{\sim}41wk$), T-2 showed highest feed intake(107.1g) among treatments, later laying period($42{\sim}77wk$), T-1 showed highest feed intake(134.3g) and was not any different among each treatments.

• Journal of Korean Home Economics Education Association
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• v.26 no.1
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• pp.81-99
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• 2014

Student teaching is equivalent to an egg just before oviposition. There is a growing acting voice that teaching profession is not necessarily required as the years go by. I developed a process that 55 student teachers search for their identity as a teacher during four-week student teaching program according to Clandinin and Connelly(2000)'s narrative inquiry. The procedure consisted of three stages such as access to the field, field text writing, and research text writing. The student teachers wrote journals by week to search for their identity as a teacher with a focus on what they observed in the field and what they were motivated by teachers and students. Free and truthful 220 stories conducted in a student teaching online cafe were collected as a field text. And the research text was reliving and retelling through poetic writing on each week's themes of exploration, growth, reflection, and pledge to complete the narrative inquiry. Student teachers, an absolute majority, including home economics student teachers aimed for the teaching profession and waited for their hatching.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.298-306
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• 2015

This study is the material of the additional filter(Cu, Ni, CaWO4, Gd+Ba) being used when the diagnosis X-ray was varied to evaluate the spatial dose distribution accordingly. And it suggest to find a suitable material. Experiments using MCNPX program based on the Monte Carlo simulation method was carried out by selecting the chest and abdomen taken. As a result, each material per dose, the average scatter dose is approximately 62%, 100 cm radius of the point of the simulated body surface exposure dose and 50 cm radius centered on the point average about 47%. It is determined that an Al material is currently available in accordance with the result to be replaced by Cu, Ni material is sufficient. With just the thickness due to the difference in the atomic number and density adjusted to be about one-tenth of the Al it will be suitable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.9
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• pp.862-876
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• 1991

In this theses, the procedure for finding the equivalent immittance of an n-line coupled structures is presented in terms of the normal mode parameters of the n-line coupled system. The above generalized equations can be applied to the various Coupled structures including directional couplers, DC blocks, bandpass/band elimination filters, and various other uniformly coupled filters. The design equations are based on a simplified TEM(Quasi TEM) mode. The obtained results and the definition of the scattering parameters for a general coupled line four port with arbitrary terminations are used to present the procedure to determine the optimum physical dimensions matching the given load impedances connected to input, output port. Multiple coupled rnicrostrip two-port with three lines circuit designed shows little discrepancy between the conventional method and this one. Four port with five lines were fabricated on teflon substrate($e$r=2.55) with its thickness h=l.588mm designed at the center frequency, 4 GHz. Their measured results are fairly close to the ones by computation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1092-1100
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• 2011

A C-band ground-based rotational SAR system is presented in this paper. The rotaional SAR system is a test-bed for future rotational SAR systems which can be deployed in space and on a tower. The test-bed system is designed for imaging the electromagnetic scattering from earth surfaces and buried targets. This paper also presents the examination results of the generated SAR images. This rotational SAR system is basically consisted of the network-analyzer based HPS(Hongik Polarimetric Scatterometer) and a horizontally rotating arm. Several SAR images were obtained using the rotational SAR system for various target areas. To verify this system, we simulated the SAR images for the rotational SAR using the FDTD algorithm and compared between the measured and simulated SAR images. The rotational SAR system is operated at the center frequency of 5 GHz and various frequency bandwidth within 0.5~2 GHz to change the resolution of SAR images.

• Progress in Medical Physics
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• v.25 no.1
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• pp.23-30
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• 2014

The purpose of this study is to evaluate the developed dose verification program for in vivo dosimetry based on transit dose in radiotherapy. Five intensity modulated radiotherapy (IMRT) plans of lung cancer patients were used in the irradiation of a homogeneous solid water phantom and anthropomorphic phantom. Transit dose distribution was measured using electronic portal imaging device (EPID) and used for the calculation of in vivo dose in patient. The average passing rate compared with treatment planning system based on a gamma index with a 3% dose and a 3 mm distance-to-dose agreement tolerance limit was 95% for the in vivo dose with the homogeneous phantom, but was reduced to 81.8% for the in vivo dose with the anthropomorphic phantom. This feasibility study suggested that transit dose-based in vivo dosimetry can provide information about the actual dose delivery to patients in the treatment room.