• Computers and Concrete
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• 제6권3호
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• pp.203-223
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• 2009

Regression analysis (RA) can establish an explicit formula to predict the strength of High-Performance Concrete (HPC); however, the accuracy of the formula is poor. Back-Propagation Networks (BPNs) can establish a highly accurate model to predict the strength of HPC, but cannot generate an explicit formula. Genetic Operation Trees (GOTs) can establish an explicit formula to predict the strength of HPC that achieves a level of accuracy in between the two aforementioned approaches. Although GOT can produce an explicit formula but the formula is often too complicated so that unable to explain the substantial meaning of the formula. This study developed a Backward Pruning Technique (BPT) to simplify the complexity of GOT formula by replacing each variable of the tip node of operation tree with the median of the variable in the training dataset belonging to the node, and then pruning the node with the most accurate test dataset. Such pruning reduces formula complexity while maintaining the accuracy. 404 experimental datasets were used to compare accuracy and complexity of three model building techniques, RA, BPN and GOT. Results show that the pruned GOT can generate simple and accurate formula for predicting the strength of HPC.

• Journal of Biosystems Engineering
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• 제36권4호
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• pp.285-289
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• 2011

Muscle fatigue is characterized as a progressive increase in discomfort arising from the active muscle at moderate load levels are maintained. The median frequency is the most commonly used as a parameter to describe muscle fatigue. However, the estimate of the median frequency is difficult to indicate muscle fatigue because of its high standard deviation and instability. This paper investigates the power changes of the appropriate low frequency band as a fatigue parameter in EMG during isotonic exercise. To select the appropriate band, linear regression lines are employed to calculate the slopes and the coefficient of determination. Three females and seven males volunteered to participate in surface EMG recordings placed on the biceps brachii and each recording experiment continued until their exhaustion. The results of experiment shows that the power changes of the selected low frequency band (15~45 Hz) have linear slopes and high determinant coefficients. Therefore, this fatiguing parameter using the power changes of the low frequency band is valid to measure the state of muscular fatigue.

• 한국안전학회지
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• 제32권5호
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• pp.129-134
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• 2017

This study aims to develop the traffic accident models by circular intersection type using count data model. The number of accident, the number of fatal and injured persons(FSI), and EPDO are calculated from the traffic accident data of TAAS. The circular intersection accident models are developed through Poisson and negative binomial regression analysis. The main results of this study are as follows. First, the null hypotheses that there are differences in the number of traffic accidents, FSI and EPDO by type of circular intersections are rejected. Second, the scale of intersection(median, large), number of approach road, mean width and length of exit road, area of the circulating roadway and central island are selected as factors influencing the number of traffic accidents, FSI and EPDO in rotary. Third, the scale of intersection(median), guide signs(limited speed, direction, roundabout), number of approach road, entry angle, area of the intersection and central island are adopted as factors influencing the number of traffic accidents, FSI and EPDO in roundabout. Finally, transferring from rotary to roundabout could be expected to make the accident decrease.

• 대한가정학회지
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• 제43권1호
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• pp.129-144
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• 2005

The purposes of this study were to find the general trends and differences factors influencing single mothers' psychological well-being, and, analyze the effects of family, and social variables on their psychological well-being. The subjects were the 284 single mothers living in Kwangju and Chonnam. The data were analyzed with frequency, t, F, and Pearson's r test, and by multiple regression using SPSS. The major findings were as follows: 1. Single mothers' family variables were lower than the median, but instrumental support was higher than emotional support. Single mothers' psychological well-being was found to be around that of the median value. 2. Single mothers' psychological well-being was significantly different from family stress, family resources, mother-child conflicts, income, emotional support, participation of education program, and institutional support. 3. Life satisfaction of single mothers was influenced by institutional support, family stress, family resources, and emotional support. Depression among single mothers was influenced by family stress, family resources, mother-child conflicts, and institutional and emotional support.

• 보건행정학회지
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• 제13권4호
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• pp.115-130
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• 2003

Reperfusion delay in patients with acute myocardial infarction leads to increased morbidity and mortality. We sought to measure the rates of reperfusion delay and to identify factors associated with reperfusion delay after arrival to hospitals. We included 360 patients who had acute myocardial infarction with ST-elevation or left bundle branch block on electrocardiogram and received reperfusion therapy from the three participating academic medical centers from 1997 to 2000. Through retrospective chart review, we collected data about time to reperfusion therapy, patient and hospital factors potentially associated with reperfusion delay. Factors independently associated with reperfusion delay were determined by logistic regression analysis. Median door­to­needle time was 60.0 minutes, and median door­to­balloon time was 102.5 minutes. According to recommendation of the American College of Cardiology/American Heart Association Guidelines, 226 out of 264(85.6％) of thrombolytic patients and 43 out of 96(44.8％) percutaneous transluminal coronary angioplasty(PTCA) patients experienced reperfusion delay. The significant factors associated with delay were type of reperfusion therapy, patient factors including hypertension and delayed symptom onset to presentation(>4 hours), and hospital factors including nocturnal presentation(6pm∼8am), weekend, and an individual hospital. A significant proportion of patients experienced reperfusion delay. The identified predictors of reperfusion delay may help design a hospital system to reduce the delay in reperfusion therapy

• Structural Engineering and Mechanics
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• 제42권5호
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• pp.631-644
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• 2012

Current seismic codes require from the seismically designed structures to be capable to withstand inelastic deformation. Many studies dealt with the development of different inelastic spectra with the aim to simplify the evaluation of inelastic deformation and performance of structures. Recently, the concept of inelastic spectra has been adopted in the global scheme of the performance-based seismic design through capacity-spectrum methods. In this paper, the median of the ductility demand ratio for 80 ground motions are presented for different levels of normalized yield strength, defined as the yield strength coefficient divided by the peak ground acceleration (PGA). The influence of the post-to-preyield stiffness ratio on the ductility demand is investigated. For fixed levels of normalized yield strength, the median ductility versus period plots demonstrated that they are independent of the earthquake magnitude and epicentral distance. Determined by regression analysis of the data, two design equations have been developed; one for the ductility demand as function of period, post-to-preyield stiffness ratio, and normalized yield strength, and the other for the inelastic deformation as function of period and peak ground acceleration valid for periods longer than 0.6 seconds. The equations are useful in estimating the ductility and inelastic deformation demands for structures in the preliminary design. It was found that the post-to-preyield stiffness has a negligible effect on the ductility factor if the yield strength coefficient is greater than the PGA of the design ground motion normalized by gravity.

• 대한인간공학회지
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• 제32권6호
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• pp.541-547
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• 2013

Objective: The aim of this study is to find the influence on muscle fatigue by changing an angle of neck while Shaker exercise. Background: Shaker exercise is commonly applied to dysphagia patients for strengthen suprahyoid muscle(SHM) and relaxing upper esophageal sphincter. Method: Experiments were conducted by measuring muscle fatigue with surface electromyography(SEMG) in case of neck $15^{\circ}$ and $50^{\circ}$ flexion, in addition to original method. For the study 30 undergraduate students were participated as subjects. Muscle fatigue was measured with variations of median frequency(MF) and median frequency slope(MFS) by attaching SEMG to 3 muscles. At the same time, perceived exertion was measured by using Borg's rating of perceived exertion(RPE). Results: A MF was increased when low angle in SHM, both male and female. It means that muscle fatigue was significantly decreased(p<.05). RPE was significantly increased when low angle(p<.01). Perceived exertion explained 15.2% of the variation of MF in SHM. And regression equation was, MF in SHM = 59.918 + (4,910 * RPE). Conclusion: The outcome shows that it is possible to use the efficient method which makes muscle fatigue decrease by reducing the angle of neck flexion. Application: The results might contribute to develop the effective Shaker exercise method.

• 가정간호학회지
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• 제25권2호
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• pp.209-218
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• 2018

Purpose: This study is to identify the health promoting behaviors, health belief, and self-efficacy of visiting nurses working for the Health Visiting Project in Seoul and to determine the predictors of influencing health promoting behaviors. Methods: Data were collected from an online survey of 496 visiting nurses form 25 districts in Seoul. Using SPSS ver. 24, the study performed descriptive statistics, t-test, one-way ANOVA, correlations, and stepwise multiple regression. Results: The mean scores for health promoting behaviors and self-efficacy were slightly higher than that of the median, whereas health belief showed in the median. The factors influencing health promoting behavior were perceived barriers, perceived sensitivity, self-efficacy, and age. These variables explained 36.0% of health promoting behaviors(F=60.62, p<.05). Conclusion: To prevent illness and to promote the health of the population, the visiting nurse mainly performs health screening, health education and counseling. To fulfill these responsibilities, the visiting nurse should be healthy and perform health promoting behaviors well, effectively serving as a model for their clients. Most of the visiting nurses were middle-aged, thus, it is necessary to strengthen health promotion activities that manage physical and psychological health at the individual level.

• 대한가정학회지
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• 제41권1호
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• pp.139-153
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• 2003

The purposes of this study were to find the general trends of aged couples' marital conflict, life satisfaction, and to examine relationships between husbands' marital conflict, life satisfaction and those of wives, and to investigate effective variables influencing on their life satisfaction. The subjects were the 218 couples over 60 years old living in Gwangju. Trained researchers interviewed the subjects with structured questionnaires. Data were analyzed with mean, sd, Cronbach' α, paired-t test, Pearson's correlation and Hierarchical Regression using SAS program. The major findings were as follows; 1. The marital conflict scores of husbands and wives were lower than median and wives' marital conflict scores were higher than those of husbands. The average scores of life satisfaction were higher than median and Husbands achieved higher scores in life satisfaction than wives. 2. Husbands' marital conflict and life satisfaction were positively related to those of wives. 3. Husbands' life satisfaction was influenced by health, self-esteem, filial support, acquaintances' support, marital conflict. Wives' life satisfaction was influenced by income, health, marital intimacy, filial support, acquaintances' support, marital conflict. Spouses marital conflict was significantly effective variable to wives' life satisfaction, but no significant to husbands'.

• Journal of Gastric Cancer
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• 제16권2호
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• pp.78-84
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• 2016

Purpose: The aim of this study was to determine whether surgical resection of the primary tumor contributes to survival in patients with metastatic gastric cancer. Materials and Methods: A total of 288 patients with metastatic gastric cancer from the Akdeniz University, Antalya Training and Research Hospital, and the Meram University of Konya database were retrospectively analyzed. The effect of primary tumor resection on survival of patients with metastatic gastric cancer was investigated using the log-rank test. Kaplan-Meier survival estimates were calculated. Multivariate analysis was performed using Cox proportional hazards regression modeling. Results: The median overall survival was 12.0 months (95% confidence intewrval [CI], 10.4~13.6 months) and 7.8 months (95% CI, 5.5~10.0 months) for patients with and without primary tumor resection, respectively (P<0.001). The median progression-free survival was 8.3 months (95% CI, 7.1~9.5 months) and 6.2 months (95% CI, 5.8~6.7 months) for patients with and without primary tumor resection, respectively (P=0.002). Conclusions: Non-curative gastrectomy in patients with metastatic gastric cancer might increase their survival rate regardless of the occurrence of life-threatening tumor-related complications.