• Smart Structures and Systems
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• v.21 no.3
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• pp.349-358
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• 2018

This paper investigates the free vibration analysis of double-beam system coupled by a two-degree-of-freedom mass-spring system. In order to generalize the model, the main beams are assumed to be elastically restrained against translation and rotation at one end and free at the other. Furthermore, the mass-spring system is elastically connected to the beams at adjustable positions by means of four translational and rotational springs. The governing differential equations of the beams and the mass-spring system are derived and analytically solved by using the Fourier transform method. Moreover, as a second way, a finite element solution is derived. The frequency parameters and mode shapes of some diverse cases are obtained using both methods. Comparison of obtained results by two methods shows the accuracy of both solutions. The influence of system parameters on the free vibration response of the studied mechanical system is examined.

• Safety and Health at Work
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• v.6 no.3
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• pp.211-217
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• 2015

Background: E-learning-based programs have recently been introduced to the occupational safety and health (OSH) education for migrant workers in Korea. The purpose of this study was to investigate how the factors related to migrant workers' backgrounds and the instructional design affect the migrant workers' satisfaction with e-learning-based OSH education. Methods: The data were collected from the surveys of 300 migrant workers who had participated in an OSH education program. Independent sample t test and one-way analysis of variance were conducted to examine differences in the degree of learning satisfaction using background variables. In addition, correlation analysis and multiple regression analysis were conducted to examine relationships between the instructional design variables and the degree of learning satisfaction. Results: There was no significant difference in the degree of learning satisfaction by gender, age, level of education, number of employees, or type of occupation, except for nationality. Among the instructional design variables, "learning content" (${\beta}=0.344$, p < 0.001) affected the degree of learning satisfaction most significantly, followed by "motivation to learn" (${\beta}=0.293$, p < 0.001), "interactions with learners and instructors" (${\beta}=0.149$, p < 0.01), and "previous experience related to e-learning" (${\beta}=0.095$, p < 0.05). "Learning environment" had no significant influence on the degree of learning satisfaction. Conclusion: E-learning-based OSH education for migrant workers may be an effective way to increase their safety knowledge and behavior if the accuracy, credibility, and novelty of learning content; strategies to promote learners' motivation to learn; and interactions with learners and instructors are systematically applied during the development and implementation of e-learning programs.

• Steel and Composite Structures
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• v.20 no.4
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• pp.869-887
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• 2016

The socket-spigot template supporting system is widely used in engineering applications in China. As a newer type of support structure, there has been growing research interest in its bearing capacity. In this paper, four vertical bearing capacity tests were carried out on the basic mechanical unit frame of a socket-spigot template supporting system. The first goal was to explore the influence of the node semi-rigid degree and the longitudinal spacing of the upright tube on the vertical bearing capacity. The second objective was to analyze the displacement trend and the failure mode during the loading process. This paper presents numerical analysis of the vertical bearing capacity of the unit frames using the finite element software ANSYS. It revealed the relationship between the node semi-rigid degree and the vertical bearing capacity, that the two-linear reinforcement model of elastic-plastic material can be used to analyze the socket-spigot template supporting system, and, through node entity model analysis, that the load transfer direction greatly influences the node bearing area. Finally, this paper indicates the results of on-site application performance experiments, shows that the supporting system has adequate bearing capacity and stability, and comments on the common work performance of a socket and fastener scaffold.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.2 s.115
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• pp.9-15
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• 2006

Neutral sizing is required for linerboard to solve the troubles in strength and process caused by recycled raw materials. AKD sizing efficiency can be influenced by process condition like white water quality, fines retention and so on. Therefore, this study was aimed to evaluate sizing performance of general and fast cure type AKDs using process water obtained from linerboard mill. To evaluate effect of process water quality on AKD sizing, white water was diluted with tap water at the different dilution ratios and UKP slurry was sized using the prepared water. Also, effects of inorganic and organic ion material on sizing were examined. When white water was used for stock forming, UKP sheet showed very low sizing degree. Sizing degree of sheet was increased with increase of dilution ratio because water quality was improved. Especially anionic organic material had a greater influence on AKD sizing than inorganic material. When white water quality was deteriorated, fast cure type AKD showed superior sizing performance to general type AKD.

• Journal of Korean Clinical Health Science
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• v.4 no.2
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• pp.571-581
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• 2016

Purpose. This study was to identify the relationship between self-directed learning and nursing student's satisfaction of clinical practice. Methods. This study was designed to measure the level of satisfaction according to the contents, guidance, environment, time, and the evaluation of clinical practice. Two hundred thirty-one nursing student from baccalaureate program in H-gun was sampled. A scale consisting of 75 questions, developed by the researcher, was used to gather data from September 14 through 27, 2012. The data was analyzed by descriptive statistics, paired t-test, pearson correlation, and multiple linear regression using the SPSS WIN 18.0 program. Results. The results were summarized : Self-directed learning didn't show a significant different by grade(t=0.83, p=.934). Nursing student's satisfaction of clinical practice didn't show a significant different by grade(t=0.26, p=.798). The relationship between self-directed learning correlated with the degree of nursing student's satisfaction in clinical practice(r=.44, p<.001). The factors of self-directed learning described nursing student's satisfaction of clinical practice as $R^2$=.215(F=9.858, p<.001). Conclusions. It was found that a higher degree of satisfaction in clinical practice depends on a higher degree of self-directed learning. Therefore, nursing faculty should plan intervention to improve satisfaction level of clinical practice by fostering self-directed learning.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.6
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• pp.86-95
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• 2007

This paper presents the optimal design of an exhaust system of a vacuum-compatible air bearing using a genetic algorithm. To use the air bearings in vacuum conditions, the differential exhaust method is adopted to minimize the air leakage, which prevents air from leaking into a vacuum chamber by recovering air through several successive seal stages in advance. Therefore, the design of the differential exhaust system is very important because several design parameters such as the number of seals, diameter and length of an exhaust tube, pumping speed and ultimate pressure of a vacuum pump, seal length and gap(bearing clearance) influence on the air leakage, that is, chamber's degree of vacuum. In this paper, we used a genetic algorithm to optimize the design parameters of the exhaust system of a vacuum-compatible air bearing under the several constraint conditions. The results indicate that chamber's degree of vacuum after optimization improved dramatically compared to the initial design, and that the distribution of the spatial design parameters, such as exhaust tube diameter and seal length, was well achieved, and that technical limit of the pumping speed was well determined.

• Korean Journal of Adult Nursing
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• v.16 no.4
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• pp.585-596
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• 2004

Purpose: This study is to examine the effect of balance taping therapy applied on the old people who suffer from arthritis upon the pain in legs and obstacle in daily activity. Methods: The research period was from Dec. 2003 to Feb. 2004, and among the old female people who visited one of the welfare halls in Seoul downtown and 4 assembly hall for old people who aged over 60 years. 30 of the experimental group and 33 of control group were optionally collected. Results: The pain degree in legs and the uneasiness degree of the obstacle in the daily life of the experimental group who were treated by the balance taping was decreased than those of the control group(p=0.015, p=0.000). Conclusions: Based upon the above result, it was confirmed that the balance taping therapy has influence in decreasing the degree of the uneasiness in the leg pain and daily activity obstacle of the old people who suffer from the arthritis, and therefore it is thought that this therapy can be usefully applied for one of the nursing methods for the old patients, and besides the repeated future researches are needed.

• Journal of the Ergonomics Society of Korea
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• v.29 no.2
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• pp.183-188
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• 2010

The purpose of this study is to investigate the stationarity of the electromyographic signal in various flexion angles, loads, and window sizes, which influence the result of the mean power frequency (MPF) and median frequency (MNF) analysis. Six healthy subjects participated in the experiment. They were tested in the combination of 3-level flexion angles (0 degree, 22.5 degree, 45 degree) and 3-level loads (0Nm, 30Nm, 60Nm). Electromyographic data were collected for 20 seconds during isometric contraction. The stationarity of collected data were analyzed with four different window sizes including 250, 500, 1000 and 2000ms. Two test methods for stationarity such as Reverse Arrangements Test and Modified Reverse Arrangements Test were used. In order to show the effect of nonstationarity, the increasing/decreasing trend of MPF and MNF trend were discussed. In results, the stationarity of the electromyographic signal decreased as flexion angle increased and load decreased while window size decreased based on Reverse Arrangements Test. The highest stationarity was shown at 500 ms window in Modified Reverse Arrangements Test. The inclination of MNF and MPF indicated 3.6-6.3%, 3.8-5.1% discrepancy compared to the result from stationary data.

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1109-1117
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• 2006

To investigate the influence of the mesophyll cells on stomatal opening in response to white light, the segments of isolated epidermis were transferred on partly exposed mesophyll cells of a leaf and stomatal apertures were measured. Transferring the isolated epidermis on partly exposed mesophyll cells of a leaf caused a marked increase on stomatal apertures while stomata in isolated epidermis incubated in MES buffer hardly opened. Mesophyll infiltration with photosynthetic inhibitors (DCMU, DCCD, $NaN_3$) was performed to elucidate the correlation between stomatal apertures and the degree of photosynthetic activity. It was found that transferring the isolated epidermis on partly exposed mesophyll cells of a leaf caused an increase of stomatal apertures depending on the degree of photosynthetic activities. In $NaN_3$ infiltrated leaf discs, transferring the fresh isolated epidermis on partly exposed mesophyll cells of a leaf showed no significant effect, but a slight increase on stomatal apertures. Isolated epidermis alone did not respond to the light properly, but if it was closely contacted with mesophyil cells, the stomata regained the ability of the light response. Therefore, it could be suggested that stomatai apertures were related with the degree of photosynthetic activity in the mesophyll cells.

• Journal of the Korean Home Economics Association
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• v.39 no.4
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• pp.19-33
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• 2001

The purpose of this study was to examine the influence of mothers'depression and children's perception of parents' behavior on children's competencies. The subjects were 729 mothers and their children with grade 5 and 6 in the five elementary schools located in T city. Data were analysed by frequency, percentile, mean, standard deviation, one-way ANOVA, scheff test and regression analysis. The levels of mothers' depression were found to be statistically different according to the parents'educational level, fathers' occupation, and the average monthly house income. The degree of children's positive perception of parents' behavior was different according to the parents'educational level and average monthly house income. And the degree of children's competencies was different according to mother's age, parents'educational level, father's occupation and average monthly house income. Mother's depression affected children's perception of their parents' behavior, suggesting that the lower the degree of mother's depression is, the more positively children tend to perceive parents' behavior. The most important factor that affected the whole areas of children's competencies was the children's positive perception of their mothers'behavior, and the next important factor was mothers' depression.