• Nutrition Research and Practice
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• v.4 no.1
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• pp.51-57
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• 2010

We performed this study to examine lifestyle patterns and dietary behavior based on the level of Internet addiction of Korean adolescents. Data were collected from 853 Korean junior high school students. The level of Internet addiction was determined based on the Korean Internet addiction self-scale short form for youth, and students were classified as high-risk Internet users, potential-risk Internet users, and no risk Internet users. The associations between the students' levels of Internet addiction and lifestyle patterns and dietary behavior were analyzed using a chi-square test. Irregular bedtimes and the use of alcohol and tobacco were higher in high-risk Internet users than no risk Internet users. Moreover, in high-risk Internet users, irregular dietary behavior due to the loss of appetite, a high frequency of skipping meals, and snacking might cause imbalances in nutritional intake. Diet quality in high-risk Internet users was also worse than in potential-risk Internet users and no risk Internet users. We demonstrated in this study that high-risk Internet users have inappropriate dietary behavior and poor diet quality, which could result in stunted growth and development. Therefore, nutrition education targeting high-risk Internet users should be conducted to ensure proper growth and development.

• Journal of Korean Public Health Nursing
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• v.3 no.1
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• pp.5-17
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• 1989

The purpose of this study was to investigate the natural menopause age of middle-aged women in Korea and to analyse various factors affecting them. For the collection of date, 1,140 women aged between 45-54 were selected through stratified sampling technics in Seoul and at a rual area in Kyong KiProvince. They were interviewed from Nov. 1 through Dec. 31,1987 by use of questionnaires made after pilot study had been performed twice. Among them the final subjects for analysis were restricted to only those who had experienced menopause or irregular menstruation during the past one year, the number of which was total 410:206 in urban and 204 in rural area. For the analysis, menopause age was used as dependent variables while fertility variables, socio-economic variables, bio-physical varibles, and insight of life variables were classified as independent variables. Dependent variables such as menopause was tested and analysed by descriptive statistical methods(e.g., frequency, percentage, mean, $X^2-test.$ t-test, ANOVA). The relation between menopause age and independent variables was analysed by use of Pearson's correlation coefficients. For the analysis of various factors affecting menopause age, multiple stepwise regression method was used. The obtained results are summarized as follows: 1. The natural menopause age of Korean women were 47.2 mean age: it was 47.7 and 46.7 mean age in urban and rural area respectively, which revealed that the former was later then the latter by one year. And the recollective error on menopause starting age between the menopause group and the group who had experienced irregular menstruation during the past one year was 0.4-0.7 year. 2. The main factors affecting the menopause age were (1) the duration of marital life, (2) the duration of oral pill use, (3) insight of life and economic status, (4) educational background. (5) menarche, (6) usual menstruation amount, (7) electic charge. and (8) area. These factors. altogether, could explain $18.4\%$ of factors related with menopause, and they took the high percentage in the order mentioned.

• Journal of muscle and joint health
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• v.26 no.3
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• pp.232-240
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• 2019

Purpose: The purpose of this study was to investigate the effects of exercise intention, exercise habit, exercise self-efficacy on exercise behavior with elders at welfare center. Methods: The subjects were 152 elders at the welfare center at J city. Data were collected using the questionnaires which consisted of the Exercise intention scale and the Exercise habit scale developed by Lee and Gu (2018), and the Exercise self-efficacy scale developed by Lee and Chang (2001). The collected data were analyzed with the SPSS/WIN 22.0 program, which was used for frequency, percentage, mean, standard deviation, x² test, and multiple logistic regression. Results: The regular exercise group consisted of 92 elders (62.5%) and the irregular exercise group of 60 elders (39.5%). The scores for exercise intention, exercise habits, exercise self-efficacy were 3.28±0.70, 3.92±0.61, 2.80±0.88 in regular exercise group, and 2.38±0.99, 3.00±1.07, 2.04±0.73 in irregular exercise group, respectively. Two groups were significantly different between the two groups. Multiple logistic regression analysis showed that exercise intention (OR: 2.26, 95% CI:1.19~4.28), exercise habits (OR: 1.79, 95% CI:1.01~3.15), exercise self-efficacy (OR: 1.99, 95% CI:1.11~3.57) were affecting factors for regular exercise in elders. Conclusion: To increase the regular exercise behaviors of the elderly at the welfare center, it is needed the strategies to increase exercise intention, exercise self-efficacy, and exercise habits.

• Journal of Korean Society of Steel Construction
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• v.14 no.1
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• pp.23-29
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• 2002

Many of the bridge systems, including the girders and cross-beams, and concrete decks behave as the special orthotropic plates. Such systems with boundary conditions other than Navier or Levy solution types, or with irregular cross sections, analytical solution is very difficult to obtain. Numerical method for eigenvalue problems are also very much involved in seeking such a solution. A method of calculating the natural frequency corresponding to the first mode of vibration of beam and tower structures with irregular cross-sections was developed and reported by Kim in 1974. Recently, this method was extended to two dimensional problems including composite laminates, and has been applied to composite plates with shear deformation effects. In this paper, application of this method to the specially orthotropic laminated plates with various boundary condition is accomplished and the result of analysis is presented.

• The Journal of Korean Physical Therapy
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• v.22 no.2
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• pp.61-68
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• 2010

Purpose: The purpose of this study was to investigate (1) job satisfaction, (2) general characteristics and (3) working fields of 57 physical therapists at public health centers in the Seoul Metropolitan area. Methods: We distributed questionnaires to 57 physical therapists and collected completed questionnaires from 51 We analyzed the data using frequency analysis, independent t-tests and analysis of variance. Results: The results were as follows; 1) General characteristics of participants were 68.6% female, 64.7% over 35 years old, 43.1% working over 10 years in the public health centers. 2) Most (56.8%) participants treated 20~29 patients a day 66.7% were regular staff members and 33.3% irregular ones. 3) Participants, who worked at the public health center and who worked at the Seoul Metropolitan affiliated organization, showed a sense of dignity about their job. 4) Regular staff members showed a higher satisfaction rate with interpersonal relations than irregular ones. Satisfaction in the work place was greatly increased in those over 40 years old. Conclusion: Because the number of patients who visit physical therapists in Seoul Metropolitan public health centers have been increasing, it is necessary to improve the level of satisfaction of physical therapists so that there will be better physical therapy services.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.5
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• pp.873-887
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• 2015

The springing response of a large blunt ship was considered to be influenced by a second order interaction between the incoming irregular wave and the blunt geometry of the forebody of the ship. Little efforts have been made to simulate this complicated fluid-structure interaction phenomenon under irregular waves considering the second order effect; hence, the above mentioned premise still remains unproven. In this paper, efforts were made to quantify the second order effect between the wave and vibrating flexible ship structure by analyzing the experimental data obtained through the model basin test of the scaled-segmented model of a large blunt ship. To achieve this goal, the measured vertical bending moment and the wave elevation time history were analyzed using a higher order spectral analysis technique, where the quadratic interaction between the excitation and response was captured by the cross bispectrum of two randomly oscillating variables. The nonlinear response of the vibrating hull was expressed in terms of a quadratic Volterra series assuming that the wave excitation is Gaussian. The Volterra series was then orthogonalized using Barrett's procedure to remove the interference between the kernels of different orders. Both the linear and quadratic transfer functions of the given system were then derived based on a Fourier transform of the orthogonalized Volterra series. Finally, the response was decomposed into a linear and quadratic part to determine the contribution of the second order effect using the obtained linear and quadratic transfer functions of the system, combined with the given wave spectrum used in the experiment. The contribution of the second order effect on the springing response of the analyzed ship was almost comparable to the linear one in terms of its peak power near the resonance frequency.

• Journal of agricultural medicine and community health
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• v.23 no.1
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• pp.51-64
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• 1998

This study was carried out during 3 years from March 1992 to March 1995, 140 healthy people and 140 C.V.A patients were investigated, at an oriental clinic in Taejon. The data collected was analysed using a SAS. The results are as follows. 1. The Relationships between patients who have undergone one or more abortion procedures and C.V.A occurrence. A statistical significant difference was recorded between the control group and the outpatients group of P<0.05 2. Number of years after initial C.V.A diagnosis before C.V.A symptom onset. within 1 years 52% (2-3 years, 3-4 years, 4-5 years, 5 years and over) 3. Additional diseases occurring after initial stroke 1 disease 50.7% (2, 3, 4, 5 or more) 4. Alcohol Consumption "A statistical significant difference was recorded between the control group and the outpatients group of" P<0.01 5. Previous Treatment Experience for stoke outpatients Oriental Hospital, clinic 64.3% (General Hospital, clinic, a public health center drug store, home remedies, etc) 6. Exercise Frequency Outpatients Regular 28.6%, Irregular 71.4% Control sample Regular 27%, Irregular 72.9% 7. Degree of Appetite "A statistical significant difference was recorded between the control group and the outpatients group of" P<0.01 8. People who include fish in their diet "A statistical difference was recorded between the control group and the outpatients group of" P<0.01.

• The Journal of the Acoustical Society of Korea
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• v.28 no.3
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• pp.174-186
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• 2009

When we apply a propagation model to the ocean with boundaries, we can calculate reflected wave using reflection coefficient suggested by Rayleigh assuming the boundaries are flat. But boundaries in ocean such as sea surface and sea bottom have an irregular rough surface. To calculate the reflection loss for an irregular boundary, it is needed to compute the coherent reflection coefficient based on an experimental formula or scattering theory. In this article, we derive the coherent reflection coefficients for a fluid-fluid interface using perturbation theory, Kirchhoff approximation and small-slope approximation respectively. Based on each formula, we can calculate coherent reflection coefficients for a rough sea surface or sea bottom, and then compare them to the Rayleigh reflection coefficient to analyze the reflection loss for a random rough surface. In general, the coherent reflection coefficient based on small-slope approximation has a wide valid region. Comparing it with the coherent reflection coefficients derived from the Kirchhoff approximation and perturbation theory, we discuss a valid region of them.

• 한국기계연구소 소보
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• s.14
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• pp.135-144
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• 1985

A method is described to obtain the first order force and second order steady force on the fixed two dimensional submerged or semisubmerged cylinders at infinite depth of water due to regular waves. The first order diffraction wave velocity potential which describes the flow diffracted by a body is obtained numerically using source distribution method on the mean wetted surface. And a technique to remove the irregular frequency phenomena of the source distribution method is also applied. The second order steady force is calculates by means of direct integration of the pressures on the body as derived from the first order velocity potential and is also computed by means of reflection wave height derives from momentum conservation theory. The results are compared with those of published works, and show good agreement.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.163-165
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• 2005

최근 GPS의 이상 현상에 대한 대비 핀 독자 항법 시스템을 구축하기 위해 유럽의 갈릴레오 일본의 QZSS 등 세계 선진각국의 GPS에 독립적인 위성항법시스템을 구축하고 있으며 GPS의 백업 용도로 지상항법 시스템인 Loran의 현대화 작업 등이 진행되고 있다. 국내에서도 독자항법에 대한 필요성이 거론되었고 해양수산부는 해상 밀 국내 전 지역을 커버할 수 있는 신호 영역을 가진 DGPS 신호의 대체항법 및 시각동기 인프라로서의 활용성에 대해 정책적으로 접근하고 있다. GPS 보정 정보를 방송하는 DGPS 비콘 신호는 중파 대역으로 지표를 따라 전파되는 특성이 있다. 지표를 따라 전파되는 지표파는 지형의 전도율과 고도에 의해 전파의 전파시 추가 지연이 발생하고 이 추가 지연은 항법 린 시각동기에 오차를 유발하게 된다. 본 논문은 DGPS 신호가 지형의 특성에 따라 지연되는 전파 특성 및 전파지연모델을 소개하고 해당 전파지연모델 구현 결과를 기존 연구결과와 비교$\cdot$검증하여 그 결과를 제시한다.