• Journal of Families and Better Life
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• v.25 no.4
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• pp.1-16
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• 2007

The purpose of this study is to examine adolescent future orientation in relation to education, work and career, and marriage and family. This study also explores the effects of adolescent future orientation in relation to their psychosocial characteristics: self-esteem, self-control, scholastic performance, and sexual permissiveness. Data were collected from 345 students in the second grade (male: 166, female: 179) of two middle schools in Seoul, Korea. Scale for adolescent future orientation was formulated based on literature review. The major findings of this study were as follows. Adolescents were found to be more future-oriented in the areas of work and career and in the area of marriage and family than in the area of education. Several hierarchical multiple regression analyses were also performed to examine the contribution of socio-demographic characteristics and future orientation to predictions of adolescent psychosocial characteristics. This study found that adolescent future orientation significantly predicted their self-esteem, self-control, and scholastic performance, while having no significant influence on sexual permissiveness.

• Tunnel and Underground Space
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• v.24 no.3
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• pp.201-211
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• 2014

In the present study, the thermal performance of multiple rock caverns for large-scale thermal energy storage (TES) was numerically investigated for different separation distances between the caverns through heat transfer analysis using a computational fluid dynamics code, FLUENT. The thermal performance of multiple caverns was assessed in terms of the thermal stratification within the caverns and the heat loss to the surroundings, and the heating characteristics of the rock around the caverns were investigated. The results of numerical simulation showed that there was little difference in thermal performance between multiple TES caverns with different separation distances when the surrounding rock was less heated and it reached thermal steady-state, which represent the thermal states of the surrounding rock at the early and long-term operational stages of the TES caverns, respectively. However, as the separation distance decreased, the rock between the caverns reached thermal steady-state more quickly, and thus the heat loss from the caverns tended to converge rapidly to the value of heat loss occurred under thermal steady-state conditions in the surrounding rock. This result implies that the operating cost of heating the surrounding rock (i.e., rock heating) can be reduced with a reduction in the separation distance between multiple caverns, and suggests that the separation distance should be determined by considering the operating cost of rock heating as well as the construction cost of the caverns.

• Journal of the Korean Data and Information Science Society
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• v.20 no.4
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• pp.713-717
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• 2009

The purpose of this paper is to analyse the factors influencing satisfaction, reliance, and loyalty to the life insurance companies. The factors are divided into two categories: the characteristics of life insurance companies and sellers. Factor analysis and multiple regression is employed. Two factors are found in the analysis of the characteristics of life insurance companies. Those are quality and social liability of life insurance companies. One factor are extracted from the analysis of the characteristics of sellers. We also find each one factor in the factor analysis of satisfaction, reliance, and loyalty. The findings are summarized as follows. Firstly, the role of sellers are very important for the three performance variables, namely satisfaction, reliance, and loyalty. Secondly, the factor for social liability of life insurance companies is statistically significant to the satisfaction performance. Finally, The three explaining variables are statistically significant to the reliance and loyalty performance.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.12
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• pp.689-697
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• 2005

In this paper, an application of a decentralized $H_{\infty}$ controller(DHC) to multiple controlled-permanent magnet(CMAG) magnetic levitation(Maglev) systems is presented. The designed DHC using two Riccati equations iteratively has simpler structure and needs less computational loads than conventional centralized $H_{\infty}$ controller. A target plant is a hybrid-type CMAG system with permanent magnet and coil, and its mathematical model is firstly derived to design the DHC. To implement the designed algorithm, a real Maglev vehicle system including digital controller, chopper, sensor, etc., is manufactured. To compare the performances of the DHC method with an observer-based state feedback control(OSFC), the input tracking and disturbance rejection characteristics are experimentally tested. As performance indices(PI), integral of squared error(ISE), integral of absolute error(IAE), integral of time multiplied by absolute error(ITAE) and integral of time multiplied by squared error(ITSE) are used. From the experimental results, it can be seen that the input tracking and disturbance rejection performances of the DHC are better than those of the conventional controller.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2053-2058
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• 2008

It was investigated thermal performances on two array types of a serial circulation and a two-way parallel circulation for six water-cooled cold plates covered with non-metallic material (polycarbonate, PC) to reduce weight of the cooling devices for humanoid robot cooling. Six cold plates attached on $10{\times}10\;mm^2$ copper base : $0.5{\times}0.5\;mm^2$ pin-finned surfaces of 1.5 mm high with 0.5 mm array spacing, was mounted on six copper heating blocks with isothermal conditions of $50{\sim}90^{\circ}C$, respectively. In order to compare thermal characteristics according to two circulation types, the surface temperatures of heating blocks and the cooling water temperatures at inlets and outlets of cold plates were measured. From the results, it was found that a two-way parallel circulation was better performance than a serial circulation in terms of total thermal resistance, total heat transfer rate, and surface temperature rises from $1^{st}$ heating block to last one for six multiple cold plates.

• Health Policy and Management
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• v.13 no.2
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• pp.101-124
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• 2003

Performance of public hospitals is difficult to define and measure because not only their managerial or financial performance but also their role as a public entity is important. The purpose of this paper is to examine the internal and external factors that influence the performance of local government hospitals. A multiple regression was performed to analyze the effects of the environmental, organizational, operational, and cost-related factors on the return on total assets(ROA), operating margin(OM), and the ratio of Medicaid patients. Empirical results show that financial performance (ROA and OM) are more influenced by operational or cost-related factors, while the ratio of Medicaid patients is more affected by environmental or organizational characteristics. It is noteworthy that competition and the contract with private sector management have negative effects on the ratio of Medicaid patients that local government hospitals treat.

• Korean Journal of Community Nutrition
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• v.5 no.4
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• pp.672-682
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• 2000

The purpose of this study was to identify the effect of job characteristics, job performance and organizational commitment on job satisfaction of hospital dietitians. The first survey was carried out on 74 hospital dietitians to determine their demographic characteristics, job characteristics, organizational commitment, and job satisfaction. The second survey was carried out on 47 hospital foodservice dietitians to determine their job performance. Thirty-two percent of the subjects were aged between 26 and 30, and 62.2% had Bachelor's degrees. The dietitians felt most satisfied by their co-workers, followed by the work-itself, supervision, pay, and promotion possibilities. Dietitians who had a higher education were satisfied with pay and supervision. The longer the length of employment, the more the satisfaction with the work-itself and pay, plus the higher the monthly wage the more the satisfaction with the work-itself, pay, supervision, and co-workers. lob satisfaction was high in the group that scored high on autonomy, feedback, task identity, and friendship of in the job characteristic inventory. The job performances of nutrition counseling(r= 0.469, p < 0.01), nutrition education(r= 0.446, p < 0.01) and management of therapeutic diet(r= 0.394, p < 0.01) were positively correlated with job satisfaction. The $R^2$for the multiple regression model was 0.677, indicating that 67.7% of the variance in job satisfaction could be accounted for by feedback, organizational commitment, nutrition counseling performance, and nutrition education performance. In conclusion, the level of job satisfaction for hospital dietitians would appear to improve with increased feedback, organizational commitment, and opportunity for nutrition counseling and nutrition education.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.3-9
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• 2016

Current mobile communication systems utilize the multiple-input multiple-output (MIMO) transmission technique as an important means to enhance the bandwidth efficiency. Accurate beamforming via channel estimation contributes to the signal-to-interference-plus-noise ratio (SINR) increase and the system performance improvement when MIMO transmission techniques are employed. Therefore, determination of beamforming vectors as well as the design of appropriate codebooks defining these codevectors play an important role in system operation. In this paper, we statistically analyze the phase difference between the channels corresponding to adjacent antenna elements in order to design an efficient codebook for uniform circular arrays (UCAs). We introduce new parameters which compensate for the additional phase difference observed in its probability density functions (PDFs). The performance of the proposed codebook is tested using the spatial channel model (SCM) to demonstrate its gain over the standard codebooks adopted in the long term evolution (LTE) Releases 8 and 10.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.296-314
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• 2016

This paper presents experimental and computational investigations of synthetic jets with a circular exit for improving flow control performance. First, the flow feature and vortex structure of a multiple serial circular exit were numerically analyzed from the view point of flow control effect under a cross flow condition. In order to improve separation control performance, experimental and numerical studies were conducted according to several key parameters, such as hole diameter, hole gap, the number of hole, jet array, and phase difference. Experiments were carried out in a quiescent condition and a forced separated flow condition using piezoelectrically driven synthetic jets. Jet characteristics were compared by measuring velocity profiles and pressure distributions. The interaction of synthetic jets with a freestream was examined by analyzing vortical structure characteristics. For separation control performance, separated flow over an airfoil at high angles of attack was employed and the flow control performance of the proposed synthetic jet was verified by measuring aerodynamic coefficient. The circular exit with a suitable hole parameter provides stable and persistent jet vortices that do beneficially affect separation control. This demonstrates the flow control performance of circular exit array could be remarkably improved by applying a set of suitable hole parameters.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.183-188
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• 2009

The High speed electrical multiple train having a distributed electrical motor system has just been developing to aim the experimental maximum speed at 400km/h since August, 2007. This project comes in stage of basic design and so, it needs to take some review and analysis the characteristics of suspensions on the view of basic design. The vehicle model for dynamic analysis is made from the concept design model that used for the preliminary design review with Vampire program and it is modeled with three linear secondary dampers and two shear springs separated from the bush elements in previous model. The optimization technique is applied to search the proper range of linear characteristics for the suspension elements to satisfy the stability performance at speed 130m/s (about 460km/h). The results shows there are some optimum points according to the variation of primary and secondary suspension characteristics and it would be useful to make a decision to select the proper suspension elements in the precision design that will be done by the manufacturing company.