• Wind and Structures
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• 제30권6호
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• pp.633-648
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• 2020

The objective of this work was to investigate the interference effects of two-parallel bridge decks on aerodynamic coefficients, vortex-induced vibration, flutter instability and flutter derivatives. The two bridges have significant difference in cross-sections, dynamic properties, and flutter speeds of each isolate bridge. The aerodynamic static tests and aeroelastic tests were performed in TU-AIT boundary layer wind tunnel in Thammasat University (Thailand) with sectional models in a 1:90 scale. Three configuration cases, including the new bridge stand-alone (case 1), the upstream new bridge and downstream existing bridge (case 2), and the downstream new bridge and the upstream existing bridge (case 3), were selected in this study. The covariance-driven stochastic subspace identification technique (SSI-COV) was applied to identify aerodynamic parameters (i.e., natural frequency, structural damping and state space matrix) of the decks. The results showed that, interference effects of two bridges decks on aerodynamic coefficients result in the slightly reduction of the drag coefficient of case 2 and 3 when compared with case 1. The two parallel configurations of the bridge result in vortex-induced vibrations (VIV) and significantly lower the flutter speed compared with the new bridge alone. The huge torsional motion from upstream new bridge (case 2) generated turbulent wakes flow and resulted in vertical aerodynamic damping H1^* of existing bridge becomes zero at wind speed of 72.01 m/s. In this case, the downstream existing bridge was subjected to galloping oscillation induced by the turbulent wake of upstream new bridge. The new bridge also results in significant reduction of the flutter speed of existing bridge from the 128.29 m/s flutter speed of the isolated existing bridge to the 75.35 m/s flutter speed of downstream existing bridge.

• Nutrition Research and Practice
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• 제10권4호
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• pp.433-441
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• 2016

BACKGROUND/OBJECTIVES: The purpose of this study was to develop a dish-based semiquantitative food frequency questionnaire (FFQ) for Korean adolescents and evaluate its reproducibility and validity. SUBJECTS/METHODS: Based on 24-hour dietary recall data from the 4th Korean National Health and Nutrition Examination Survey (KNHANES), we developed a FFQ with 71 items. From a quota sample of 160 adolescents recruited using gender and age group as stratification variables, 153 participated in the complete data collection process. The FFQ was administered to each subject twice, at an interval of 3-4 weeks, to evaluate the test-retest reliability. The validity of the FFQ was assessed relative to 8-day food record data. RESULTS: The study findings demonstrated the FFQ's satisfactory reproducibility. Spearman correlation coefficients ranged from 0.64(for ${\beta}-carotene$) to 0.81(for protein). From cross-classification analyses, the proportion of subjects in the same intake quartile was highest for protein (65.4%) and lowest for vitamin A(47.1%). With regard to validity analysis, Spearman correlation coefficients ranged from 0.27(for vitamin A and fiber) to 0.90 (for energy). The proportions of subjects in the opposite categories between the first FFQ and the 8-day food record data were generally low within the range from 0.74% (for energy and carbohydrate) to 13.2% (for ${\beta}-carotene$). CONCLUSIONS: In conclusion, the dish-based semiquantitative FFQ developed in this study can be useful for grouping Korean adolescents according to major macro- and micronutrient intakes with reasonable reproducibility and validity.

• 한국융합학회논문지
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• 제8권11호
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• pp.133-139
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• 2017

본 연구는 통학버스를 이용하는 대학생의 안전띠 착용에 대한 인식, 태도 및 실천 정도를 분석하기 위한 서술적 조사연구이다. 연구대상은 통학버스를 이용하는 대학생 118명이며, 자기기입식 구조화된 설문지를 이용하였다. 수집된 자료는 SPSS WIN 22.0 프로그램으로 분석하였고, 기술통계, Pearson correlation coefficients, t-test와 ANOVA를 실시하였으며 Scheffe's test로 사후검정을 실시하였다. 본 연구에서 안전띠 착용에 대한 인식, 태도 및 실천 간에는 유의한 양의 상관관계가 있는 것으로 나타났으며, 안전띠 착용에 대한 인식은 대상자의 마지막 안전띠 미착용 시점에 따라 차이가 있었고, 태도는 성별, 연령, 안전띠 미착용 시점에 따라, 실천은 대상자의 성별, 연령, 통학시간, 안전띠 미착용 시점, 경제적 수준에 따라 차이가 있었다. 본 연구 결과는 통합적인 안전사고 예방 보건교육 프로그램을 개발하는데 기여할 수 있을 것으로 사료된다.

• 한국항해학회지
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• 제23권2호
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• pp.29-42
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• 1999

An accurate method of estimating ship maneuverability needs to be developed to evaluate precisely and improve the maneuverability of ships according to the water depth. In order to estimate maneuverability by a mathematical model. The hydrodynamic forces acting on a ship hull and the flow field around the ship in maneuvering motion need to be estimated. The ship speed new the berth is very low and the fluid flow around a ship hull is unsteady. So, the transient fluid motion should be considered to estimate the drag force acting on the ship hull. In the low speed and short time lateral motion, the vorticity is created by the body and grow up in the acceleration stage and the velocity induced by the vorticity affect to the body in deceleration stage. For this kind of problem, CFD is considered as a goof tool to understand the phenomena. In this paper, the 2D CFD code is used for basic consideration of the phenomena to solve the flow in the cross section of the ship considering the ship is slender and the water depth is large enough. The flow fields Added and hydrodynamic forces for the some prescribed motions are computed and compared with the preliminary experiment results. The comparison of the force with measurement is shown a fairly good agreement in tendency. The 3D Potential Calculation based on the Hess & Smith Theory is employed to predict the surge, sway added mass and yaw added moment of inertia of hydrodynamic coefficients for M/V ESSO OSAKA according to the water depth. The results are also compared with experimental data. Finally, the sway added mass of hydrodynamic coefficients for T/S HANNARA is suggested in each water depth.

• The Journal of Korean Physical Therapy
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• 제29권3호
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• pp.122-127
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• 2017

Purpose: The aim of this study was to investigate if the 7-item Berg balance scale (BBS) 3-point, which is a short form of the BBS (SFBBS), has compatible psychometric properties in comparison with the original BBS, and also to study the concurrent validity using a 10-meter walk test (10mWT) and a timed up and go test (TUG), which are widely used with SFBBS in clinical settings. Methods: A total of 255 patients who had experienced stroke participated in this cross-sectional study. We used results obtained from 188 patients who completed both 10mWT and TUG. The three levels in the center of the BBS were collapsed to a single level (i.e.,0-2-4) to form the SFBBS. The concurrent validity was assessed by computing the Spearman coefficients for correlation among outcome measures and in between each outcome measure and the SFBBS. As there were four outcomes, the corrected p-value for significant correlation was 0.013 (0.05/4). Results: Spearman coefficients for correlations and evaluation instruments for concurrent validity revealed significantly high validity for both of SFBBS and BBS (r=0.944). 10mWT and TUG were -0.749 and -0.770 respectively, which are in the high margin and are statistically significant (p>0.000). Conclusion: SFBBS has sound psychometric properties for evaluating patients with stroke. Thus, we recommend the use of SFBBS in both clinical and research settings.

• 대한화학회지
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• 제22권5호
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• pp.304-310
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• 1978

혈장내의 중요한 성분인 몇가지 염들이 poly(2-hydroxyethyl methacrylate) 격막을 통과하는 상대투과계수($U_{re}$), 분배계수($K_D$), 확산계수($D_m$)등을 측정하였다. 이 격막을 제조할 때 cross-linker로서 사용된 tetraethylene glycol dimethacrylate(TEGDMA)의 함량은 중량비로 2.8%였다. 이 염들의 확산계수는 그 분자량이 증가함에 따라서 지수함수적으로 감소하였으며, 그 분자의 원통반지름(a)에 대해서는 요소를 제외하고는 직선적으로 감소하였다. 이와 같은 사실을 sieve pore filow 모델로서 설명하였다. 여러 온도에서 요소의 $U_{re}$와 $D_m$은 글리신, ${\beta}$-알라닌, D-글루코오스, 사카로스 및 말레산과 같은 다른 염들의 값보다 더 컸다. 이와 같은 결과는 이 poly(HEMA) 격막이 혈투석 응용에 적합하다는 사실을 보여 주었다.

• 대한의용생체공학회:의공학회지
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• 제36권4호
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• pp.103-108
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• 2015

Discrimination of Parkinson's disease (PD) from Essential tremor (ET) is often misdiagnosed in clinical practice. Since tremor is time-varying signal, and dominant and harmonic frequencies are shown in tremor only with moderate or severe symptom, there are some limitations to use frequency related features. Moreover, patients with PD or ET can suffer from both resting tremor and postural tremor. In this study, 28 patients with PD and 17 patients with ET were enrolled. Tremor was measured with accelerations on the more affected hand during resting and postural conditions. The ratio of root mean square (RMS) of resting tremor to RMS of postural tremor, the mean coefficients of autocorrelation function (ACF), and the mean of differences of two adjacent coefficients of ACF at resting and postural were calculated and compared between PD and ET. The performance showed 98% accuracy with support vector machine and leave-one-out cross validation. In addition, the method accurately differentiated the patients with tremor-dominant PD from patients with ET, with 100% accuracy. Therefore, the developed algorithm can assist clinicians in diagnosing and categorizing patients with tremor, especially, patients with mild symptom or the early stage of a disease, for proper treatment.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.5078-5087
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• 2014

본 연구는 노인대학을 다니는 노인의 자아존중감, 생활만족도 및 삶의 질을 파악하고 자아존중감과 생활만족도가 삶의 질에 미치는 영향을 파악하기 위한 횡단적 서술적 조사연구이다. 자료수집은 2013년 11월 18일부터 11월 29일 까지 G시에 소재한 3곳의 노인대학을 다니는 노인 269명을 대상으로 하였으며, 수집된 자료는 SPSS WIN 20.0을 이용하여 t-test, ANOVA, Pearson's correlation coefficients, multiple regression으로 분석하였다. 연구결과, 대상자의 삶의 질은 자아존중감(r=-.338, p<.001), 생활만족도(r=-.507, p<.001)는 유의한 음의 상관관계가 있는 것으로 나타났다. 그리고 연구 대상자의 삶의 질에 미치는 요인을 다중회귀로 분석한 결과, 생활 만족도(${\beta}$=-.512, p<.001)는 통계적으로 유의한 것으로 나타났으며, 모형의 설명력을 나타내는 결정계수($R^2$)는 .251로 이 모형의 설명력은 25.1% 이었다. 이상의 결과를 바탕으로 지역사회 차원에서 노인들의 건강관리 서비스를 통합하여 노인의 삶의 질을 향상을 향상시킬 수 있는 체계적인 간호중재 프로그램이 개발되어야 할 것이다.

• 한국전문물리치료학회지
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• 제15권1호
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• pp.12-19
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• 2008

The purpose of this study was to determine the relationship between activities of daily living and health-related quality of life in ambulatory stroke patients. This was a cross-sectional survey study of 60 patients who had survived one year or more after a stroke in community. Activities of daily living were assessed using the Functional Independence Measure (FlM) and health-related quality of life using the Stroke Impact Scale (SIS). The association between FIM and SIS was examined using Pearson' s correlation. The FIM score was higher than the SIS score. Most domains of FIM exhibited a high rate (45-85%) of ceiling effects. However, only the communication and memory domain of SIS exhibited of ceiling effects. The correlation coefficients were .835 (p<.01) for FIM-motor vs. SIS-ADL, .257 (p<,05) for FIM-motor vs. SIS-communication, .596 (p<.01) for FIM-motor vs. SIS-social participation, .635 (p<.01) for FIM-cognition vs. SIS-memory, .369 (p<.01) for FIM-cognition vs. SIS-ADL, and .289 (p<.05) for FlM-cognition vs. SIS-social participation. In conclusion, the correlation between FIM-motor and SIS-social participation was higher than that of FlM-cognition and SIS-social participation. The domains of emotion and hand function of SIS showed no correlation coefficients with FIM-total. To examine the activities of daily living and the quality of life in ambulatory stroke patients in community, it is necessary to use both the FIM and SIS.

• 대한수의학회지
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• 제30권2호
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• pp.171-175
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• 1990

항체로서 4-pregnen-$11{\alpha}$-ol-3,20-dione-hemisuccinate bovine serum albumin을 사용하여 progesterone 측정을 위한 방사선 면역분석법을 개발하였다. 항체의 최종 희석 배율은 1 : 5,000이었다. Label progesterone의 회수율은 84%였으며 최저 측정치는 8pg/ml이었다. Intra- and interassay coefficients of variation은 각각 6.2, 10.4%이었다. 방사선 면역 분석법은 가축에서 성성숙(性成熟), 발정확인(發情確認), 임신진단(姙娠診斷), 분만(分娩)후 난소기능회복(卵巢機能回復) 및 번식장애(繁殖障碍)의 진단(診斷)등에 적용될 수 있을 것으로 사료된다.