• 한국학교보건학회지
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• 제13권2호
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• pp.283-293
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• 2000

The following results were obtained after data adjustment and analysis of a study consisting of self-writing, of oral check-ups and questionnaires of 356 students of the O middle school in Suwon in June of 2000. The purpose of this study was to discover the effects of the dental health types of middle school students on dental caries and to understand the specific teeth of dental health types due to educational experience. Based on such data, we want to develop a desirable educational program for middle school dental heath. 1. The DMFT index was higher in females (0.75+4.39) than males(4.99+3.67), so there was a significant difference(p=0.000) 2. The DMFT index increased from the ages of 12 (4.69+3.90). 13 (5.69+3.67), 14 (6.18+4.39) and 15(6.98+4.08) and were significantly different (p=0.011). 3. There was no difference in the DMFT index regarding the method of brushing, educational experience for dental health, oral hygiene index and plaque index in dental health types. Yet, the more snack-eating increased the higher the DMFT index increased; thus, there was found a significant difference (p=0.0006). The more fluoride use increased, the lower the DMFT index; thus, there was a significant difference (p=0.048). As for the self-awareness index of dental health, the ones who answered positively had a DMFT index of 2.14+ 1.83 and those who answered negatively had a DMFT index of 7.00+3.94; thus, there was a significant difference (p=0.000). 4. For those who had had educational experience in dental health, a rolling method was used in brushing, and the frequency of fluoride use was high; the self-awareness index of dental health was high as well.

• 한국도로학회논문집
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• 제11권2호
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• pp.27-35
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• 2009

본 연구는 국내에 적합한 지불규정을 도입하기 위해 아스팔트 포장의 품질측정 방법을 제시하고자 수행되었다. 지불규정은 통계이론을 바탕으로 포장의 품질을 결정하여 시공비용을 조정하는 방법으로 지불규정을 적용하는 미국 대다수의 주에서는 고유의 품질테이블을 이용해 PWL(Percent With in Limit)을 산정한다. 따라서 미국 South Carolina에서 적용중인 품질측정테이블을 사용한 PWL과 통계분석방법에 기초한 확률이론의 비교분석을 통해 PWL의 국내 적용여부의 가능성을 판단하였다. 시험포장구간의 데이터를 사용하여 통계이론을 이용해 산출한 확률값과 PWL을 미국AASHTO에서 제시한 지불계수(Pay Factor)에 대입한 결과는 큰 차이를 보이지 않았으며 확률값 도출을 위한 Z-Value산출과정에서 모집단의 평균을 추정해 계산한 확률값 역시 PWL과 유사한 값을 보였다. 또한 현행 아스팔트 포장의 시방규정을 만족하지만 표준편차가 큰 가상의 데이터를 이용하여 지불계수를 산정한 결과 데이터의 평균값은 현행 시방규정에 만족하지만 지불계수는 100%이하로 산정되는 경우가 있는 것을 알 수 있었다. 이는 PWL방법을 이용함으로써 균질하고 성능이 우수한 품질의 측정이 가능한 것을 의미하며 따라서 국내실정에 접합한 품질측정테이블을 개발하여 PWL을 국내 지불규정의 품질측정방법으로 사용하는 것이 적합한 것으로 판단되었다.

• 한국건설관리학회논문집
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• 제5권6호
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• pp.203-211
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• 2004

본 연구는 전문가를 대상으로 한 델파이(Delphi) 설문조사를 통하여 물가 변동에 따른 건설공사 계약 금액 조정(escalation) 제도의 문제점 및 개선 방안에 대하여 살펴본 결과이다. 조사 결과, 에스컬레이션의 요건이 되는 건설공사비의 등락률은 소비자 물가 변동률 혹은 건설 공사비 지수에 근거하여 결정하는 것이 바람직하며, 전문가의 의견을 보면, 총 공사금액의 $3\%$ 수준이 적정한 것으로 나타났다. 나아가 환율 및 국제 원자재 가격 등 단기적 충격 요인에 기인하는 자재 가격의 급등은 건설업체가 사전적으로 예측하여 대응하는 것이 어렵다. 따라서 단품슬라이드 제를 도입하여 특정 자재의 가격 급등에 대하여 에스컬레이션을 허용할 필요성이 있다. 등락률의 산정 방식으로는 지수조정률보다는 개별 공사의 특성을 정확하게 반영할 수 있는 품목조정률이 더 바람직한 것으로 평가되었다. 지수조정률이 합리적으로 기능하기 위하여는 품목별 공종별로 노임지수와 자재지수, 기계경비지수 등이 산출되어 발표될 필요성이 있다. 에스컬레이션의 기산일로서는 현행 법령에서는 계약 체결일로 규정되어 있으나, 계약 체결 이전부터 물가 변동이 발생한다는 점을 고려할 때, 입찰일로 규정하는것이 바람직하다.

• 대한한의학회지
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• 제42권4호
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• pp.185-196
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• 2021

Objectives: Many symptoms of cold and heat patterns are related to the thermoregulation of the body. Thus, we aimed to study the association of cold and heat patterns with anthropometry/body composition. Methods: The cold and heat patterns of 2000 individuals aged 30-55 years were evaluated using a self-administered questionnaire. Results: Among the anthropometric and body composition variables, body mass index (-0.37, 0.39) and fat mass index (-0.35, 0.38) had the highest correlation coefficients with the cold and heat pattern scores after adjustment for age and sex in the cold-heat group, while the correlation coefficients were relatively lower in the non-cold-heat group. In the cold-heat group, the most parsimonious model for the cold pattern with the variables selected by the best subset method and Lasso included sex, body mass index, waist-hip ratio, and extracellular water/total body water (adjusted R² = 0.324), and the model for heat pattern additionally included age (adjusted R² = 0.292). Conclusions: The variables related to obesity and water balance were the most useful for predicting cold and heat patterns. Further studies are required to improve the performance of prediction models.

• 제어로봇시스템학회논문지
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• 제6권3호
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• pp.273-283
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• 2000

In this paper we suggest an optimal design method of Fuzzy-Neural Networks(FNN) model for complex and nonlinear systems. The FNNs use the simplified inference as fuzzy inference method and Error Back Propagation Algorithm as learning rule. And we use a HCM(Hard C-Means) Clustering Algorithm to find initial parameters of the membership function. The parameters such as parameters of membership functions learning rates and momentum weighted value is proposed to achieve a sound balance between approximation and generalization abilities of the model. According to selection and adjustment of a weighting factor of an aggregate objective function which depends on the number of data and a certain degree of nonlinearity (distribution of I/O data we show that it is available and effective to design and optimal FNN model structure with a mutual balance and dependency between approximation and generalization abilities. This methodology sheds light on the role and impact of different parameters of the model on its performance (especially the mapping and predicting capabilities of the rule based computing). To evaluate the performance of the proposed model we use the time series data for gas furnace the data of sewage treatment process and traffic route choice process.

• 한국항해학회지
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• 제5권2호
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• pp.49-58
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• 1981

One of the main purposes of the marine gyrocompass follow-up system is to preserve the sensitive part from the wandering error due to the frictional or torsional torque around the vertical axis. This error can be diminished through the rapid follow-up action, which minimizes the relative azimuthal angular displacement between the sensitive and follow-up parts and shortens the duration of the same displacement. But an excessive rapidity of the follow-up action would result in a sustained oscillation to the system. Therefore, to design a new type of the follow-up system, the theoretical annlysis of the problems concerned should be studied systematically by introducing the control theory. This paper suggest a concrete procedure for the optimal adjustment of the gyrocompass follow-up system, utilizing the mathematic model and the stability informations formerly investiaged by the author. For theoptimal determination of the adjustable paramfter K, the performance index(P.I.), ITSE(Intergral of the Time multiplied by the Squared Error) is proposed, namely, P.I. = $\int_{0}^{\infty} t \cdot e^{2}(t)dt$ where t is time and e(t) means control error. Then, the optimal parameter minimizing the performance index is calculated by means of Parseval's theorem and numerical computation, and the validity of the obtained optimal value of the parameter Ka is examined and confirmed through the simulations and experiments. By using, the proposed method, the optimal adjustment can be performed deterministically. But, this can not be expected in the conventional frequency domain analysis. While the Mps of the original system vary to the extent of from 0.98 to 46.27, Mp of the optimal system is evaluated as 1.1 which satisfies the generally accepted frequency domain specification.

• 대한방사선기술학회지:방사선기술과학
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• 제45권1호
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• pp.41-47
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• 2022

The purpose of this study is to apply a deep learning model that can distinguish lung perfusion and lung ventilation images in nuclear medicine, and to evaluate the image classification ability. Image data pre-processing was performed in the following order: image matrix size adjustment, min-max normalization, image center position adjustment, train/validation/test data set classification, and data augmentation. The convolutional neural network(CNN) structures of VGG-16, ResNet-18, Inception-ResNet-v2, and SE-ResNeXt-101 were used. For classification model evaluation, performance evaluation index of classification model, class activation map(CAM), and statistical image evaluation method were applied. As for the performance evaluation index of the classification model, SE-ResNeXt-101 and Inception-ResNet-v2 showed the highest performance with the same results. As a result of CAM, cardiac and right lung regions were highly activated in lung perfusion, and upper lung and neck regions were highly activated in lung ventilation. Statistical image evaluation showed a meaningful difference between SE-ResNeXt-101 and Inception-ResNet-v2. As a result of the study, the applicability of the CNN model for lung scintigraphy classification was confirmed. In the future, it is expected that it will be used as basic data for research on new artificial intelligence models and will help stable image management in clinical practice.

• 디지털융복합연구
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• 제19권1호
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• pp.125-139
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• 2021

본 연구는 이익조정을 연구주제로 국내 회계학 관련 논문들의 세부 연구 동향 파악을 목적으로 한국학술지인용색인(KCI)의 회계학 또는 경영학에 속하는 학술지에 게재된 논문 초록을 텍스트 마이닝 기법을 이용하여 분석하였다. 분석 결과, 이익조정 관련 회계학 논문들이 감사 및 감사보고서, 법인세 및 부채비율, 기업의 전반적인 경영전략, 재무제표와 회계기준의 4가지 연구 영역으로 나누어지는 것을 확인하였으며, 재무제표와 회계기준이 주된 토픽일 것이라는 예측과는 달리 감사가 가장 많이 연구된 토픽으로 분석되었다. 이어 토픽별 논문 수를 기준으로 토픽 트렌드를 확인하고 특이사항에 대한 원인을 분석하였으며, K-IFRS의 도입이 이익조정 연구에 미친 영향을 확인하였다. 본 연구는 이익조정에 대한 자세한 연구 동향에 대한 정보를 제공하고 회계학 문헌분석 연구방법으로 텍스트 마이닝 기법을 제시하였다. 또한 정책결정자 및 기업 실무 담당자가 이익조정 관련하여 회계기준 외에 감사 등 4개 토픽별로 추가적으로 고려하여야 할 사항과 그 추세를 파악할 수 있도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4568-4587
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• 2014

Authentication of videos and images based on the content is becoming an important problem in information security. Unfortunately, previous studies lack the consideration of Kerckhoffs's principle in order to achieve this (i.e., a cryptosystem should be secure even if everything about the system, except the key, is public knowledge). In this paper, a solution to the problem of finding a relationship between a frame's index and its content is proposed based on the creative utilization of a robust manifold feature. The proposed solution is based on a novel semi-fragile watermarking scheme for H.264/AVC video content authentication. At first, the input I-frame is partitioned for feature extraction and watermark embedding. This is followed by the temporal feature extraction using the Isometric Mapping algorithm. The frame index is included in the feature to produce the temporal watermark. In order to improve security, the spatial watermark will be encrypted together with the temporal watermark. Finally, the resultant watermark is embedded into the Discrete Cosine Transform coefficients in the diagonal positions. At the receiver side, after watermark extraction and decryption, temporal tampering is detected through a mismatch between the frame index extracted from the temporal watermark and the observed frame index. Next, the feature is regenerate through temporal feature regeneration, and compared with the extracted feature. It is judged through the comparison whether the extracted temporal watermark is similar to that of the original watermarked video. Additionally, for spatial authentication, the tampered areas are located via the comparison between extracted and regenerated spatial features. Experimental results show that the proposed method is sensitive to intentional malicious attacks and modifications, whereas it is robust to legitimate manipulations, such as certain level of lossy compression, channel noise, Gaussian filtering and brightness adjustment. Through a comparison between the extracted frame index and the current frame index, the temporal tempering is identified. With the proposed scheme, a solution to the Kerckhoffs's principle problem is specified.

• 토지주택연구
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• 제4권4호
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• pp.407-415
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• 2013

2002년에 친환경건축물인증제도가 시행된 이후 많은 인증 수행에도 불구하고 이 제도의 효과분석이나 개선방안 노력이 저조하다. 특히 인증제도에서 에너지성능은 에너지절약설계기준에 있는 에너지성능지표(EPI)로 평가되지만 지금까지 지표에 대한 현황분석이 미비하여 개선에 어려움이 있다. 본 연구에서는 친환경 공동주택 인증단지를 대상으로 에너지성능지표간의 상관관계를 살펴보고 에너지성능지표의 각 부문별 에너지 기본 배점에 따른 점수 현황을 분석하여 지표 개선을 도모하였다. 친환경 공동주택 인증단지의 EPI 평균득점은 약 74.68점, 최소 63.40점, 최대 90점으로 편차가 큰 것으로 나타났다. 또한 인증지표 중에서 최고의 배점으로 편성된 에너지소비량의 경우, 최대 12점 배점에서 평균 7.04점으로 평균 수준에 머물고 있었다. 향후 에너지소비량 인증지표에서 등급구간의 강화 또는 산출식의 조정 등의 지표 개선이 필요하였다.