• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.174-179
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• 2004

The paper deals with gravitational effect on dynamic stability of a cantilevered pipe conveying fluid. The eigenvalue branches and modes associated with flutter of cantilevered pipes conveying fluid are fully investigated. Governing equations of motion are derived by extended Hamilton's principle, and the solutions are sought by Galerkin's method. Root locus diagrams are plotted for different values of mass ratio of the pipe, and the order of branch in root locus diagrams is defined. The flutter modes of the pipe at the critical flow velocities are drawn at every one of the twelfth period. The transference of flutter-type instability from one eigenvalue branches to another is investigated thoroughly.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.45-52
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• 1995

A prototype of a linear piezoelectric actuator is developed and its dynamic behaviors are investigated. The actuator consists of a driving tip with two stacked piezoelectric elements and a slider. Dynamic characteristics of slider over various vibration lici of the driving tip and changes of normal force acting on the vibratory tip are examined through experiments. The moving direction of slider can be controlled by changing a phase angle between input signals applied to piezoelectric elements. A change of phase difference between input signals also have a great influence on the vibration locus of driving tip. Changes of slider motion due to different vibration loci are examined by experiments.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.4 s.181
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• pp.67-74
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• 2006

The paper presents gravitational effect on eigenvalue branches and flutter modes of a vertical cantilevered pipe conveying fluid. The eigenvalue branches and modes associated with flutter of cantilevered pipes conveying fluid are fully investigated. Governing equations of motion are derived by extended Hamilton's principle, and the related numerical solutions are sought by Galerkin's method. Root locus diagrams are plotted for different values of mass ratios of the pipe, and the order of branch in root locus diagrams is defined. The flutter modes of the pipe at the critical flow velocities are drawn at every one of the twelfth period. The transference of flutter-type instability from one eigenvalue branches to another is investigated thoroughly.

• Health Policy and Management
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• v.13 no.4
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• pp.66-83
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• 2003

Self-efficacy is a person's perceived capability to perform a behavior. We have studied the antecedents of self­efficacy, and its moderating role on the relationship between job characteristics and job satisfaction. Data is collected through questionnaire from 910 employees of 6 large hospitals in Korea. The results show that individual's internal locus of control has positive relationship with self­efficacy and self-efficacy has positive relationship with job satisfaction. Contrary to the hypothesis, supervisors' transformational leadership doesn't show any relations with self­efficacy. The moderating role of self efficacy on the relationship between job characteristics and job satisfaction is supported. These results suggest that hospital managers should manage the self­efficacy as an important instrument of enhancing productivity and employee satisfaction.

• Journal of Families and Better Life
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• v.15 no.4
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• pp.253-268
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• 1997

the purpose of this study was to analyze the relationship between elderly's leissure participation and the type of leisure attitude and leisure constraints. The sample of this study consisted of 485 elderly over 55 years old living in Seoul Daejeon Jeonju and Daegu. Statistics employed for the analysis were frequencies means cross-tabs and multiple regression analysis. The results could be summarized as follows The types of leisure attitude and leisure constraints of elderly was affected by the age educational attaintment health status region total asset income pocket money family relationship locus of control and self-esteem. And educational attaintment health status region family relationship locus of control and self-esteem had effects on leisure participation level of elderly. These findings pointed that psychological factors such as family relation self-esteen and type of leisure attitude and leisure constraints were the variables explaining leisure activities of elderly.

• Journal of the Korean Home Economics Association
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• v.36 no.7
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• pp.83-96
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• 1998

The purpose of this study was the development of a scale to assess daily hassles coping behaviors for school aged children. The subjects were 398 children consisted of 197 3rd grade an 201 6th grade. They were selected from elementary school in Seoul, InCheon, DaeJeon, GwangJu and Pusan(202 males and 196 females) A questionnaire as the methodological instrument composed of 65-item daily hassles coping scale, demographic questions, 27-item Children's Depression Inventory and 20-item Locus of Control Scale. Statistics such as mean, %, X2, Cramer's V, Cronbach's α, factor analysis and Person's γ was used for used data analysis. The major findings of this study were as follows; 1)55 items of the 65-item scale were selected through item discriminant method. The discriminant coeffcients of the items(Cramer's V) ranged from .35 to .68. 2)5 factors were extracted from the 1st and the 2nd factor analysis. The subscales labelled 'active' 'passive' 'aggressive' 'avoidant' and 'social support seeking' coping. The criterion validity of this scale was assessed by computing the correlation measures of Children's Depression Inventory and Locus of Control Scale with this scale. Most coefficients were significant(ranging from r=-.16 to r=.40,p<.01,p<.001), although their correlations were modest. 3)Finally, the internal consistency of this scale appeared to be at an acceptable level(Cronbach's α=.90)

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.1729-1736
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• 2015

Background: The purpose of this study was to investigate the associations among the internal health locus of control, depression, perceived health status, self efficacy, social support, and health-promoting behavior in Iranian breast cancer survivors and to determine influential variables. Materials and Methods: A predictive design was adopted. By convenient sampling the data of 262 breast cancer survivors in Iran were collected by questionnaires during 2014. Data were analyzed applying descriptive statistics, t-tests, one-way ANOVA, Pearson's correlation coefficients, and stepwise multiple regression. Results: The internal health locus of control, depression, perceived health status, self efficacy, social support and undergoing chemotherapy all correlated significantly with the health-promoting lifestyle. Stepwise multiple regression analysis revealed that social internal health locus of control, depression, perceived health status, self efficacy and social support and chemotherapy accounted for about 39.8% of the variance in health promoting lifestyle. The strongest influence was social support, followed by self efficacy, perceived health status, chemotherapy and depression. Conclusions: The results of the study clarifed the seriousness of social support, self efficacy, perceived health status and depression in determining the health-promoting lifestyle among Iranian breast cancer survivors. Health professionals should concentrate on these variables in designing plans to promoting a healthy lifestyle.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.256-262
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• 1999

To evaluate the genetic diversity and structure of the South Korean soybean population, 233 landraces collected in various regions of the country were surveyed for 15 allozyme loci and one protein locus. The South Korean population was fixed or nearly fixed at seven of the 16 loci tested. The number of alleles per locus was 2.06 and Nei’s gene diversity was 0.194. These values were lower than the values for the same 16 loci previously reported for the Japanese and Chinese populations. The differences among eight regional groups were not so marked, with only 7.2% of the total variation arising from regional differentiation. Three southern regional groups (Chollabuk-do, Chollanam-do and Kyong-sangnam-do) exhibited a relatively high variability because of frequent occurrence of alleles characteristic of the Japanese population. A marked difference was found in allelic frequencies at the Dial locus between large-seeded landraces and small-seeded ones, suggesting that the latter, which are used mainly for bean sprouts, had been established independently of the former, which are used mostly for soy sauce and cooking with rice. Not only the region but also the usage as food materials should therefore be taken into consideration in designing an efficient collection and preservation method for the Korean soybean landraces.

• The Journal of Information Technology
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• v.3 no.1
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• pp.177-189
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• 2000

It was investigated this study how much individual's job stress would be explained by formalized task environment. also, would be explained locus of control as moderate variable. The data used in the study were collected from employees in domestic corporate. After sending the total of 150 questionnaires, 113 responses were returned. Among the returned questionnaires, 9 poor responses were excluded, and the remained 104 copies were analyzed. The final regression model included formalized task environment as statistically significant, but locus of control as statistically non-significant. it was relied on a lack of sample. This study was to open job stress studies up multi level study(individual - organizational level).

• Journal of Drive and Control
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• v.13 no.3
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• pp.15-23
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• 2016

The direct-drive servo valve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the dc motor. Since the DDV structure is simple, it is less expensive, more reliable, and offers a reduced internal leakage and a reduced sensitivity to fluid contamination. The control system of the DDV is highly nonlinear due to a current limiter, a voltage limiter, and the flow-force effect on the spool motion. The shape of the step response of the DDV-control system varies considerably according to the magnitudes of the step input and the load pressure. The system-design requirements mean that the overshoots should be less than 20%, and the errors at 0.02s should be less than 2%, regardless of the reference-step input sizes of 1V and 5V and the load-pressure magnitudes of 0MPa and 20.7MPa. To satisfy the system-design requirements, the PID-controller parameters of $K_c$, $T_i$ and $T_d$, and the derivative-feedback gain of $K_{der}$ are designed using the root locus and manual tuning.