• Journal of Radiation Protection and Research
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• 제46권4호
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• pp.204-212
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• 2021

Background: Identification of radioisotopes for plastic scintillation detectors is challenging because their spectra have poor energy resolutions and lack photo peaks. To overcome this weakness, many researchers have conducted radioisotope identification studies using machine learning algorithms; however, the effect of data normalization on radioisotope identification has not been addressed yet. Furthermore, studies on machine learning-based radioisotope identifiers for plastic scintillation detectors are limited. Materials and Methods: In this study, machine learning-based radioisotope identifiers were implemented, and their performances according to data normalization methods were compared. Eight classes of radioisotopes consisting of combinations of ²²Na, ⁶⁰Co, and ¹³⁷Cs, and the background, were defined. The training set was generated by the random sampling technique based on probabilistic density functions acquired by experiments and simulations, and test set was acquired by experiments. Support vector machine (SVM), artificial neural network (ANN), and convolutional neural network (CNN) were implemented as radioisotope identifiers with six data normalization methods, and trained using the generated training set. Results and Discussion: The implemented identifiers were evaluated by test sets acquired by experiments with and without gain shifts to confirm the robustness of the identifiers against the gain shift effect. Among the three machine learning-based radioisotope identifiers, prediction accuracy followed the order SVM > ANN > CNN, while the training time followed the order SVM > ANN > CNN. Conclusion: The prediction accuracy for the combined test sets was highest with the SVM. The CNN exhibited a minimum variation in prediction accuracy for each class, even though it had the lowest prediction accuracy for the combined test sets among three identifiers. The SVM exhibited the highest prediction accuracy for the combined test sets, and its training time was the shortest among three identifiers.

• 감성과학
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• 제17권2호
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• pp.35-44
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• 2014

본 연구에서는 VDT(Visual Display Terminals) 환경에서 배경색과 가독성의 상관관계를 알아보았다. 본 실험에 앞서 예비실험으로 색 온도가 다른 White 지각도를 알아보았으며, 실험 자극물은 태블릿 PC를 활용하였다. 실험 환경은 주광과 야외광이 함께 공존할 수 있는 창가에서 실험 자극물을 제시하였다. White 지각도의 인식과 선호 결과 중 단파장계열의 Nearly Whites 색 에서 백색에 대한 높은 선호도와 인식도를 보였다. 이러한 예비실험 결과를 바탕으로 본 연구에서는 동일한 실험 환경과 실험 기기를 가지고 빨간색, 초록색, 파란색, 노란색의 총 4가지 Nearly Whites와 한 가지 백색을 배경색으로 사용하여 배색 평가, 가독성, 피로도를 조사하였다. 또한, 글자는 검은색으로 제한하였다. 그 결과, 초록색의 Nearly White 배경색에서 가독성과 배색 평가가 높게 나타났으며, 가독 시 느끼는 피로도는 가장 낮은 것으로 나타났다. 이와 반대로 빨간색의 Nearly White 배경색에서는 가독성과 배색 평가가 가장 낮게 나타났으며, 가독 시 느끼는 피로도는 가장 높은 것으로 나타났다. 이러한 연구 결과를 통해서 VDT 환경에서의 가독성을 향상시키며, 눈의 피로도를 낮출 수 있는 배경색을 제안해 보고자한다.

• 한국학교수학회논문집
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• 제15권2호
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• pp.281-297
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• 2012

수학과 평가는 학생들의 수학적 사고력과 성취도를 측정하는데 있다. 또한 이를 분석 활용하여 수학교육의 질을 높이는데 그 목적이 있다. 이러한 평가는 좋은 문항제작에서부터 시작된다. 이에 본고는 문항제작 관련 이론을 고찰하고, 교육목표에 따른 예시 문항과 문항제작시의 유의점을 살펴보며, 계획 단계, 초안 문항제작 단계, 검토 단계, 최종 문항제작 단계 등 단계별 문항제작의 실제를 안내하고자 한다.

• 혜화의학회지
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• 제8권1호
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• pp.827-836
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• 1999

Numerous persons complained dyspepsia even though no specific objective findings are revealed by imaging study, laboratory examinations and other clinical research. To find out of so many symptoms what they are, I would to approach by two ways. One way is oriental medical literatural study and the other is Helicobacter pylori infection that is accepted as one of most important causal factors of many gastric diseases. Background/Aims: Recently, the role of Helicobacter pylori as a causal factor in the etiology of gastric cancer, peptic ulcer, gastritis and low-grade gastric mucosa-associated lymphoid tissue(MALT) lymphoma is well known. Using endoscopy, biopsy urease testing and histology are recommanded as the tests of choice. Serological test is not recommanded at the moment because of its low sensitivity and espicially low specificity. The urea breath test is more sensitive and specific noninvasive test than serologic test, but it is not widely available yet. Methods/Results: We studied 90 cases by diagnostic endoscopy as a screening test for the persons complaining gastrointestinal symptoms. As a result eighteen persons are revealed to be Helicoacter pylori infected histologicaly. Conclusion: More specific literatural studies are requied.

• 인지과학
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• 제23권3호
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• pp.409-424
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• 2012

본 연구의 목적은 상대적 위상을 이용한 시각적 협응 패턴의 지각이 조절변수의 변화에 따라 HKB 모델(Haken, Kelso, Bunz, 1985)의 예측에 따르는지 확인해 보는 것이었다. 또한 격자무늬 배경을 이용한 부가적인 시각 정보가 협응 패턴 분별의 정확성과 안정성을 향상시키는지 알아보았다. 피험자들은 일반 배경과 격자 배경 중 하나의 그룹에 속하여 패턴 지각 연습과 패턴 분별 시험을 하였다. 피험자들은 좌우로 이동하는 두 점 사이의 상대위상으로 정의된 $0^{\circ}$, $18^{\circ}$, $36^{\circ}$, $54^{\circ}$, $72^{\circ}$, $90^{\circ}$, $108^{\circ}$, $126^{\circ}$, $144^{\circ}$, $162^{\circ}$, $180^{\circ}$ 패턴을 관찰하였다. 패턴 지각 연습은 두 점의 진동 주기 0.25 Hz에서 시행되었고, 패턴 분별 시험은 0.5 Hz, 1 Hz, 2 Hz에서 시행되었다. 패턴 분별 시험에서 얻은 분별 점수, 절대 분별 오차, 분별 안정성 자료를 통계적으로 분석하였다. 분별의 정확성과 안정성은 진동 주기가 느릴 때는 "뒤집어진 U" 모양을 띄다가 진동 주기가 빨라짐에 따라 $180^{\circ}$ 상대위상 패턴에 가까운 패턴들에서 정확성과 안정성이 감소하였다. 이러한 발견은 협응 패턴의 지각적 분별 역학이 HKB 모델을 따름을 나타낸다. 부가적 환경 정보인 격자무늬가 협응 패턴 분별의 정확성과 안정성에 도움은 되지 못하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.208-212
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• 2010

The high-speed railway consists of tracks, gravel ballast and subgrade, and the dynamic load is passed to subgrade through track and gravel ballast. The relaxation condition of the gravel ballast is able to be evaluate relatively and to be repaired through a continuous management, but it is difficult to evaluate the condition of subgrade, which is final part of supporting dynamic load and to repair it when made a problem. The gravel ballast and subgrade are evaluated by determining shear wave velocity. To evaluate ballast and subgrade, a good method to determine shear wave velocity is a non-destructive experiment such as surface wave tests providing a prompt experiment because an experiment in railway has a lot of tests which are carried out following railway directions and needs to prevent damage of the system. In general, a railway has limitation of an experimental space by narrow width, sleeper and etc., and background noise by a reflector exists. The existing surface wave tests need a minimum space, and it is difficult to get a reliable test results on account of background noise effect. Therefore, it is difficult or impossible to apply to existing surface wave test of subgrade and ballast. In this study, the HWAW method is applied to determine a shear wave velocity profile of the underground. The HWAW method is the experiment which is able to be carried out on a narrow space, and it determines share wave velocity of a site by measuring the wave from surface sources on the same spot. In addition, it removes effects of background noise accordingly to a signal processing using harmonic wavelet transforms, so it is useful to evaluate subgrade of a high-speed railway in the narrow space and the situation of background noise. In order to check an application of the HWAW method, an experiment is carried out on a high-speed railway field and a test result is compared to boring results.

• 한국인터넷방송통신학회논문지
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• 제16권1호
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• pp.43-53
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• 2016

본 연구는 배경의 밝기와 색상 자극의 크기에 따라 인지될 수 있는 색상 속성이 차이가 있을 수 있다는 가정 아래, 배경의 밝기를 차등적으로 적용하여 Peripheral vision에 해당하는 $10^{\circ}$와 $20^{\circ}$의 자극을 colour matching하는 실험을 진행 하였다. 실험결과, 배경의 밝기 및 실험 자극으로 사용된 Munsell 색상 속성의 조합에 따라 동일한 색상임에도 불구하고 colour를 각기 다르게 인지할 수 있다는 경향성을 볼 수 있었으며, 자극의 크기에 대한 색상 인지 관련 선행 연구 결과와 다르게 배경의 밝기의 변화에 따라 색상 자극의 크기가 상대적으로 작다고 하더라도 더욱 colourful하거나 더욱 밝게 인지될 수 있다는 결과를 얻을 수 있었다. 본 연구에서 진행된 실험 결과를 바탕으로 향후 영상의 크기가 변환 될 때 발생할 수 있는 화질 열화를 개선할 수 있으며 2D 뿐만 아니라 3D나 홀로그램 영상처리 시, 시감적 특성을 반영한 효과적인 입체 영상 재현에도 기여할 수 있다.

• 한국도로학회논문집
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• 제16권3호
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• pp.85-99
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• 2014

PURPOSES : This study has been performed with the objective to determine threshold zone luminance of adaptation luminance by target safety level in a vehicular traffic tunnel with design speed set at 100km/h. METHODS : The study made a miniature capable of portraying changes in luminance distribution within $2{\times}10^{\circ}$ conical field of view of the driver approaching to the tunnel for the test. Test conditions were set based on justifications for CIE 88-1990's threshold zone luminance used as a reference by domestic tunnel light standards (KS C 3703 : 2010). Luminance contrast of object background and object is 23%, object presentation duration is 0.5 seconds, and size of the object background is $7.3{\times}11.5m^2$ RESULTS : Threshold zone luminance was set within adaptation luminance of $100{\sim}3,000cd/m^2$. Adaptation luminance and threshold zone luminance based on 50%, 75% and 90% target safety level all showed a relatively high linear relationship. According to findings in the study, it is not appropriate to specify the relationship between adaptation luminance and threshold zone luminance as luminance ratio. Rather, direct utilization of the linear relationship gained from the study findings appears to be the better solution. CONCLUSIONS : Findings of this study may be used to determine operation of threshold zone luminance based on target safety level. However, a proper verification and validity of test results are required. Furthermore, a study to determine proper threshold zone luminance level considering target safety level reviewed in this study and various decision-making factors such as economic conditions in Korea and energy-related policies should be carried out in addition. Additional tests on adaptation luminance greater than $3,000cd/m^2$ will be performed, through which application scope of the test findings will be broadened.

• 한국통신학회논문지
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• 제31권10B호
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• pp.857-865
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• 2006

NGN(Next Generation Network)이 약속하는 다양한 기능과 서비스가 제공될 수 있는가를 시험하고 평가하기 위해 평가방법이 필요하며 시험 대상 장치의 구성, 성능평가대상, 시험에 필요한 트래픽의 특성 등에 대한 개발이 요구되고 있다. 그간 IP패킷 성능평가방법으로 시뮬레이션(simulation)방법과 분석적 모델링(analytical modeling)방법 등 많은 연구가 수행되어 왔지만 아직까지 미흡한 실정이다. 본 논문은 NGN 통신망에 대하여 실제 운용환경과 유사한 조건을 만족시키고, 객관적이고 신뢰성 있는 성능 평가 방법을 도출하여 제시하였다. 이를 위해 시험용 트래픽(Test Traffic)과 백그라운드 트래픽(Background Traffic)을 개발하였고, IP 통신망과 동일한 장비로 구축된 시험망을 구성하여 NGN 서비스 특성을 고려한 대역폭, 패킷사이즈별로 성능평가를 수행하였다. 제안된 평가방법을 통해, 지연(Delay), 지연변이(Jitter) 손실(Loss)등의 성능평가결과를 기존의 평가방법의 결과와 비교하였을 때 제안된 평가방법이 단대단NGN 통신망의 성능평가방법으로 우수함을 입증하였다.

• 한국가정과교육학회지
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• 제3권1호
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• pp.71-94
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• 1991

The purpose of this study is to investigate the desirable method of courtesy education for middle school students. The major research questions of this study are to identify and test the follows： 1) The influence of the environment (grade, sex, the educational background of father, the educational background of mother, the scale of family, the presence of grandfather, the presence of grandmother, students’age ranking among their brothers and sisters, religion, academie record) on the middle school students’ knowledge and attitude on courtesy. 2) The influence of the courtesy education on students’knowledge and attitudes on courtesy. 3) The degree of change on their knowledge and attitudes after courtesy education. The response were given by 485 middle school students and their mothers in Wanju county Chonbuk province. Frequences, Percentages, Means and Standard Deviations were calculated, T-test and Pearson Correlation Coefficients were used for data analysis. The result of this study are as follows, 1. The influence of environment： 1) Higher grade students gained more score of courtesy test than lower grade ones. 2) Female students gained more score than male students. 3) The students who had higher academic record gained more score of courtesy test than any other students. 2. The influence of courtesy education： Most of educated groups changed significantly due to courtesy education. It showed that courtesy education contributed to improve their knowledge and attitudes on courtesy. 3. After courtesy education： On the one hand, the most changed attitude was bow-courtesy area and then good-manners area, conversation-courtesy area, etc. On the other hand, the basic spirit area on courtesy changed less than any other areas. It means that long-term courtesy education should be done in order to change students’ attitudes on courtesy basically, even though they could improve their knowledge and attitudes externally in a short time.