• 대한전자공학회논문지
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• 제23권2호
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• pp.236-242
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• 1986

The dependence of the current-voltage characteristics of hydrogenated amorphous silicon pin solar cells on the illumimination light intensity has been investigated. The open circuit voltage increases linearly with increasing the logarithm of light intensity up to AM 1, and nearly saturates above AM 1, indicating the open circuit voltage approaching the built-in potential of the pin solar cell above AM 1. The short circuit current density increase with light intensity in proportion to I**0.85 before and I**0.97 after light exposure. Since the series resistance devreses and shunt resistance increases with light intensily, the fill factor increases with light illumination. To increase the fill factor at high illumination in large area solar cells, t6he grid pattern on the ITO substrates should be made. Long light exposure on the solar cells gives rise to the increase of bulk resistance and defect states, resulting in the decrease of the fil factor and short circuit current density. The potential drop in the bulk of the a-Si:H pin solar cells at short circuit condition increases with decreasing temperature, and increases after long light exposure.

• 보건의료산업학회지
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• 제11권4호
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• pp.145-155
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• 2017

Objectives : To investigate the factors affecting bone mineral density in across stratified postmenopausal ages. Methods : Data from 1,698 subjects who completed the 2010-2011 National Health and Nutrition Survey were analyzed using SPSS Statistics 21.0 The $x^2$ test and one way (ANOVA) were used to verify the relationship between general characteristics and health behaviors and the prevalence of osteoporosis. Logistic regression analysis was used to verify the factors Influencing bone mineral density. Results : The bone mineral density distribution was the highest among those with osteopenia, with proportions of 21.8% in healthy subjects, 58.1% in osteopenia, and 20.0% in those with osteoporosis. The distribution of osteoporosis by age group was 5.2% among subjects in their 50s, 15.4% among those in their 60s, and 42.4% among those in their 70s. In multivariate logistic regression analysis, the prevalence of osteoporosis according to ages was significantly correlated with age, educational level, body mass index(BMI), and parity 4 of more than 1-2 babies. Conclusions : Although age is an uncontrollable factor in the prevention of osteoporosis, educational level and BMI are correctable factors to maintain bone mineral density. There is a need to maintain healthy BMI and expand osteoporosis prevention education.

• 대한공간정보학회지
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• 제18권1호
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• pp.3-9
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• 2010

하천에 의하여 지면이 절개되는 정도로 정의되는 배수밀도는 유역의 형태학적 응답을 포괄적으로 반영하는 자연 지형의 근본적인 특성으로 알려져 있다. 본 연구에서는 배수밀도에 대한 통계학적 접근방법을 기반으로 해당 지형 인자의 공간적 변동성을 분석하고 이로부터 배수밀도의 공간적 변동성을 도시할 수 있는 방법을 제시하였다. 지표면 유하거리의 통계학적 특성을 분석해 본 결과 이 지형인자는 고도의 공간적 변동성으로 대표되는 자연지형의 고유한 특성들 중 하나임을 확인할 수 있었다. 이로부터 본 연구에서 제시한 분포도 형태의 배수밀도는 고전적인 정의의 배수밀도보다 유용한 도구가 될 수 있을 것으로 판단된다.

• 한국간호교육학회지
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• 제12권2호
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• pp.214-223
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• 2006

Purpose: This study is to find the significant symptoms related to bone density, from which a cost-effective nursing diagnosis and intervention can be derived. Method: The research sample was 102 women, the sampling was designed by the researcher's convenience, and the subjects of the sample voluntarily participated in a questionnaire survey and measurements. The questionnaire asked socio-demographics, women' reproductive health symptoms, and the life style of the subject. Osteometer DTX-200 for bone density measure and a ruler for measuring spinal curvature were used. All the data were collected at the two public health clinics in a city in Korea. Result: The subjects' current and completed menopause ages, duration of menopause, degree of spinal curvature, BMI, frequency of parity and etc. showed significant correlations with bone density. However, only the degree of spinal curvature(p<.001, r=-.22) was found to be meaningful as a predicted factor for self diagnosis of bone density level. Conclusions: Since most of the subjects have not recognized the relationships between changes in spinal curvature and lowered bone densities, nurse needs to educate clients to get medical assistance to prevent from further bone density reduction by earlier finding of spinal curvature.

• 천문학회지
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• 제19권1호
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• pp.33-49
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• 1986

Radial distribution of internal density has been determined for thirteen subclouds in the three giant molecular cloud complexes accompanying Mon OB1, Mon OB2 and CMa OB1 associations, We modeled their radial density structures with the density distribution of isothermal gas spheres. Most of the subclouds, nine out of the thirteen, are well described by isothermal spheres of single component; while the rest four require an additional component. Total mass and potential energy of each subcloud are also derived from the radial density structure; thermal energy and internal velocity dispersion required for sustaining the density structure are deduced from the isothermal gas model. Our derived masses of the clouds are comparable to the values determined by Blitz (1978) under LTE assumption. This agreement suggests that the correction factor for non-LTE effect on mass-estimate is not far from unity. The ratio of the gravitational potential energy to the kinetic energy of thermal motion is as large as 250; hence the thermal motion alone cannot support these clouds against the gravity. Being supported by turbulence motion with velocities of six to seven times the thermal velocity, the clouds of one-component type seem to be in equilibrium with the gravity; while the clouds of two-component type are likely to be in the stage of gravitational collapse.

• 한국지반공학회논문집
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• 제23권10호
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• pp.23-31
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• 2007

상대밀도는 사질토의 역학적 특성을 나타내는 중요한 요소 중의 하나이지만 아직까지도 최대 및 최소 상대밀도를 결정하는 방법이 명확하게 규정되지 않았다. 최대 및 최소상대밀도를 결정하는 방법은 많은 학자들에 의해 연구되었으나, 기존의 방법들은 시간과 노력이 많이 소요될 뿐만 아니라, 특히 최대상대밀도는 실험방법에 따라서 상당한 차이를 보여주고 있다. 이 연구에서는 기존 방법으로 구한 최대상대밀도와 큰 오차를 보이지 않으면서도 간편하고 실질적으로 이용하기 편리한 간편법을 제안하고자 한다. 실험은 타격수와 층수를 달리해 가면서 작은 몰드를 사용하여 실시하였으며, 실험결과를 Bowles 방법과 비교하였다.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2000년도 추계학술발표회 논문집
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• pp.65-73
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• 2000

Kernel estimator is very popular in nonparametric density estimation. In this paper we propose an estimator which reduces the bias to the fourth power of the bandwidth, while the variance of the estimator increases only by at most moderate constant factor. The estimator is fully nonparametric in the sense of convex combination of three kernel estimators, and has good numerical properties.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.47-50
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• 2001

The laboratory tests were peformed to investigate the relationship between electrical resistivity and the unsaturated subsurface condition and to evaluate the contamination due to leachate based on measuring electrical resistivity. For weathered granite soil, the electrical resistivity of soil decreases as moisture density increases. The electrical resistivity of soil decreases as the concentration of leachate in pore fluid increases since leachate contains various ionic constituents. And the modified Archie's equation for applying to unsaturated sand is derived by regression analysis.

• 대한전기학회논문지
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• 제36권4호
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• pp.240-251
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• 1987

In this paper, with the end effect taken into consideration, the fundamental characteristics of a linear induction motor-the eddy currents of the secondary conducting sheet (traveller), the flux density in the air gap-are analysed by means of electromagnetic field theory. Accordingly, the derived governing eqations of the chatacteristics with goodness factor, presents that it was possible not only to predict the performance characteristics, but to obtain the data that needs to optimize a design of a motor with the reduction of the end effect.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.21-25
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• 2005

In order to implement high pixel density in AMLCDs, high aperture ratio is a very important design factor. We have implemented VGA panels with IPS and TN modes. IPS mode is a very attractive solution to meet the requirement for mobile phone displays. It provides much higher aperture ratio as well as wider viewing angle at extremely high pixel density over 400 ppi.