• 연구논문집
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• 통권33호
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• pp.89-97
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• 2003

A barrel cam is used as a very important part of an index drive unit. The index drive unit must have an intermittent-rotational motion. The barrel typed cam and roller gear mechanism has the advantages of high reliability to perform a prescribed motion of a follower. This paper proposes a new method for the shape design of the barrel cam and also a CAD program is developed by using the proposed method. As defined in this paper, the relative velocity method for the shape design calculates the relative velocity of the follower versus cam at a center of roller, and then detemines a contact point by using the geometric relationships and the kinematic constraints, where the direction of the relative velocity must be parallel to a common tangential line at the contact point of two independent bodies, i.e. the cam and the follower. Then, the shape of the cam is defined by the coordinate transformation of the trace of the contact points. This paper presents shape design of the barrel cam in order to prove the accuracy of the proposed methods

• 지능정보연구
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• 제1권2호
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• pp.103-121
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• 1995

This study proposes a artificial neural network method to predict the time to buy and sell the stocks listed on the Korea Composite Stock Price Index(KOSPI). Four types (NN1, NN2, NN3, NN4) of independent networks were developed to predict KOSPIs up/down direction after four weeks. These networks have a difference only in the length of learning period. NN5 - arithmetic average of four networks outputs - shows an higher accuracy than other network types and Multiple Linear Regression (MLR), and buying and selling simulation using systems outputs produces higher reture than buy-and-hold strategy.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.144-144
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• 2022

Identifying waterbody from remote sensing images, namely water detection, helps understand continuous redistribution of terrestrial water storage and accompanying hydrological processes. It also allows us to estimate available surface water resources and help effective water management. For this problem, NDWI (Normalized Difference Water Index) and MNDWI (Modified Normalized Difference Water Index) are widely used. Although remote sensing indexes can highlight remote sensing image in the water, the noise and the spatial information of the remote sensing image are difficult to be considered, so the accuracy is difficult to be compared with the visual interpretation (the most accurate method, but it requires a lot of labor, which makes it difficult to apply). In this study, we attempt to improve existing NDWI and MNDWI to better water detection. We establish waterbody database of South Korea first and then used it for assessing waterbody indices.

• 정보관리연구
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• 제41권2호
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• pp.161-181
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• 2010

본 연구는 국내 주요 10개 경제연구기관의 보고서를 대상으로 인터넷 뉴스에서의 인용 행태를 분석하고 각 기관의 영향력을 h-지수와 다양한 변형 지수(g-지수, $h_s$-지수, $g_s$-지수)로 제시하였다. 이를 위해 네이버 뉴스에서 기사를 검색하여 총 878건에 대한 기사의 내용 분석을 실시하였다. 먼저, 보고서 인용 기사 수, 뉴스매체, 주제 섹션, 신속성, 정확성, 중심성, 기사 길이 등을 중심으로 인용행태를 분석하였다. 다음으로 인용 건수로 영향력을 산출하여 기관 순위를 비교하였다. 분석 결과 인용 지수 순위가 상위권에 속한 기관들은 지수 간의 순위 차이가 거의 없었고, 전문가가 제시한 순위와도 유사한 반면, 중 하위권의 기관들은 상대적으로 지수에 따라 차이가 나고, 전문가 순위와 다른 양상을 보였다.

• 문화기술의 융합
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• 제10권1호
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• pp.489-493
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• 2024

행복 지수는 집단적인 행복 정도를 직관적으로 파악하는데 효과적인 측정 시스템이다. 가치관의 변화에 따라행복 지수에 행동의 가치를 추가한 연구들이 제안되고 있으나, 개인이 느끼는 감정을 활용하여 관계성을 분석한 연구는 부족한 실정이다. 따라서 본 연구는 행동의 가치를 나타내는 사회적 변수와 개개인의 감정지수를 함께 고려해 행복 지수를 예측하는 딥러닝 모델을 설계한다. 첫째, 2005년 1월 ~ 2020년 12월의 사회적, 감정적 변수를 수집한다. 둘째, 데이터 전처리 및 유의변수 탐색을 수행한다. 셋째, 딥러닝 기반의 회귀 모델로 학습하고, 5-Fold 교차 검증(Cross Validation)으로 학습 모델을 평가한다. 본 연구의 제안 모델은 테스트 데이터에서 90.65%의 높은 예측 정확도를 보인다. 향후 이 연구는 국가별 데이터로 확대 적용하여 행복 지수 주요 요인 분석 등의 연구에 활용될 수 있을 것으로 기대된다.

• 대한의용생체공학회:의공학회지
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• 제33권1호
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• pp.8-14
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• 2012

The purpose of this study was to evaluate how much effect to accuracy when measuring abdominal fat by Computed Tomography (CT) under different respiration movements. The study volunteer composed of 66 normal adults ($50.4{\pm}11.2$ years, 33 males, 33 females). We measured their obesity by using Broca index, body mass index (BMI) and CT and have investigated the correlation. The CT scanning for the obesity measurement have done in two ways, one was done in stopping breath after exhaling and the other was holding a breath after inhaling. The results showed no statistically significant difference among the three measuring techniques. And, the error in two ways of inhaling and exhaling was showed 24.2% of volunteers. The two ways of respiration movements made different result in visceral fat area (P = 0.044), subcutaneous fat area (P = 0.636) and abdominal obesity value (P = 0.012). This study demonstrates that the two ways of respiration movements when scanning CT makes change in accuracy in visceral fat area, and in abdominal obesity quantitative measure. Therefore, our study suggests that CT should take twice in two ways while a patient stops breath after exhaling and holds a breath after inhaling when measuring abdominal obesity using CT equipments.

• 전기학회논문지
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• 제58권6호
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• pp.1078-1086
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• 2009

This paper presents a Fourier based algorithm for estimating the parameters of the low frequency oscillating modes. The proposed methods estimates various parameters(frequency, damping factor, mode magnitude, phase) by fitting Fourier spectrum and phase with a damped exponential cosine function. Dominant frequency is selected by taking frequency corresponding to the peak spectrum, and damping factor is estimated using the left/right spectra of Fourier spectrum. In addition, mode magnitude is calculated by the normalized peak spectrum, and phase is estimated from spectrum phase. Also, we introduce an accuracy index in order to determine the accuracy of the estimated parameters, and the index is calculated using the deviations of the peak spectrum and the left/right spectra. The parameter estimation methods proposed in this paper include very simple arithmetical processes, so the algorithms are simple and the calculation speed is very fast. The proposed methods are applied to test functions with two dominant modes. The results show that the proposed methods are highly applicable to low frequency parameter estimation.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.46-46
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• 2017

We developed a rice simulation model for remote-sensing (SIMRIW-RS, Homma et al., 2007) to evaluate rice production and management on a regional scale. Here, we reports its application trial to estimate rice production in farmers' fields in Sendai, Japan. The remote-sensing data for the application was periodically obtained by multispectral camera (RGB + NIR and RedEdge) attached with unmanned air vehicle (UAV). The airborne images was 8 cm in resolution which was attained by the flight at an altitude of 115 m. The remote-sensing data was relatively corresponded with leaf area index (LAI) of rice and its spatial and temporal variation, although the correspondences had some errors due to locational inaccuracy. Calibration of the simulation model depended on the first two remote-sensing data (obtained around one month after transplanting and panicle initiation) well predicted rice growth evaluated by the third remote-sensing data. The parameters obtained through the calibration may reflect soil fertility, and will be utilized for nutritional management. Although estimation accuracy has still needed to be improved, the rice yield was also well estimated. These results recommended further data accumulation and more accurate locational identification to improve the estimation accuracy.

• Perspectives in Nursing Science
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• 제9권1호
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• pp.24-35
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• 2012

Purpose: This research was performed to investigate Korean adolescents' body weight perception, appropriate weight change efforts, and factors that influencing these efforts. Methods: The data were obtained from 68,136 adolescents, aged 12~18 years from the 2007 Third Korean Youth' Risk Behavior Web-based Survey. Descriptive statistical analysis and odds ratio were calculated by logistic regression. Results: The distribution of the body mass index differed in boys and girls. The accuracy of body weight perception was shown in the order of the underweight (91.6%), overweigh t (73.3%), normal weight (55.4%), obesity (41.3%) groups. Adolescents with high perceived economic status tended to have a high prevalence of accuracy of body weight perception. The distribution of appropriate weight change efforts according to the actual body mass index showed that girls were trying to lose weight more than boys. The results of a logistic regression analysis regarding appropriate weight change efforts showed differences according to gender, perceived economic status, mother's educational level, and family affluence scale. Conclusion: Appropriate body weight perception and change management plans are needed for Korean adolescents. In addition, active weight change programs have to be established in the adolescents' living environments, such as schools.

• 전기전자학회논문지
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• 제14권4호
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• pp.339-345
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• 2010

보다 빠른 내용 기반 이미지 검색을 위해, 다차원 특징 정보의 효과적인 인덱싱에 대한 다양한 연구들이 수행되고 있다. 하지만, 대부분의 인덱싱 기법들은 특징 정보의 차원이 커질수록 성능이 저하되는 문제를 가지고 있으며, 이를 대체하기 위해서 '높은 확률'로써 사용자가 원하는 결과를 제공해 주기 위한 휴리스틱 (heuristic) 알고리즘을 사용한 기법들이 제안되었다. 본 논문에서는 이러한 다차원 특징 정보를 효과적으로 인덱싱 하기 위해, 연장 해쉬 기반의 새로운 인덱싱 기법을 제안한다. 제안된 인덱싱 기법은 기존의 기법들이 가졌던 문제들을 해결하기 위해, 검색의 정확도에 영향을 주지 않으면서 빠른 검색이 가능하도록 설계되었다. 다양한 실험을 통해, 제안된 기법이 월등한 성능을 가질 수 있음을 보였다.