• Journal of Power Electronics
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• v.14 no.5
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• pp.834-841
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• 2014

This paper proposes new active switched-capacitor and switched-inductor Z-source inverter (ASC/SL-ZSI) topologies, which can provide a higher boost ability with a small shoot-through time. The proposed ASC/SL-ZSIs inherit all of the advantages of the classical ZSI, and have a stronger voltage boost inversion ability when compared with the classical ZSI. Thus, the output ac voltage quality is significantly improved. In addition, more cells can be cascaded in the impedance network in order to obtain a very high boost ability. The proposed topologies can be applied to photovoltaic or fuel-cell generation systems with low-voltage renewal sources due to their wide range of obtainable voltages. Both simulations and the experimental results are carried out in order to verify performance of the proposed topologies.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.255-262
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• 1998

This paper presents a translation, rotation and scale invariant methodology for the recognition of closed planar shape images using the bispectrum of a contour sequence and the learning vector quantization(LVQ) neural classifier. The contour sequences obtained from the closed planar images represent the Euclidean distance between the centroid and all boundary pixels of the shape, and are related to the overall shape of the images. The higher order spectra based on third order cumulants is applied to tihs contour sample to extract fifteen bispectral feature vectors for each planar image. There feature vector, which are invariant to shape translation, rotation and scale transformation, can be used to represent two0dimensional planar images and are fed into a neural network classifier. The LVQ architecture is chosen as a neural classifier because the network is easy and fast to train, the structure is relatively simple. The experimental recognition processes with eight different hapes of aircraft images are presented to illustrate the high performance of this proposed method even the target images are significantly corrupted by noise.

• Journal of Power Electronics
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• v.14 no.3
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• pp.432-443
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• 2014

In order to improve the output efficiency of solar cells and to extend the life span of batteries, the input currents of converters are required to be continuous. If low output voltage ripple is required at the same time, it is obvious that the application of basic two-order converters (such as Buck and Boost derived converters) will not be good enough. In this paper, a lot of non-isolated push-pull converters (NIPPCs) with continuous current will be introduced due to their lower current stress, higher efficiency and better EMC performance. By decomposing the converters into push-pull cells, inductor and free-wheeling diodes, two families of NIPPCs based on single inductor and coupled inductor separately are systematically generated. Furthermore, characteristics analyses for some of the generated converters are also shown in this paper. Finally, two prototypes based on the corresponding typical topologies are built in the lab to verify the theoretical outcomes.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.3
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• pp.345-357
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• 1998

This paper focuses on production planning and scheduling problems in an assembly system operating on a make-to-order basis. Due dates are considered as constraints in the problems, that is, tardiness is not allowed. Since the planning problem is a higher-level decision making than the scheduling problem, the scheduling problem is solved using a production plan obtained by solving the planning problem. We suggest heuristic procedures in which aggregated information is used when the production planning problem is solved while more detailed information is used when the scheduling problem is solved. Since a feasible schedule may not be obtained from a production plan, an iterative approach is employed in the two procedures to obtain a solution that is feasible for both the production planning and scheduling problems. Computational tests on randomly generated test problems are done to show the performance of these algorithms, and results are reported.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.2
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• pp.161-167
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• 2005

The improvements of the propulsive engine efficiencies could reduce the fuel consumption. Therefore. for a marine main diesel engine the substantial increase of stroke bore ratio. so that the engine speed can be significantly reduced in order to increase the Propulsive efficiency. As a typical example. a Sulzer RTA 60C engine has acylinder diameter of 600 mm and each cylinder is capable of delivering 2.369 kW in the speed range 91-114 rpm. In order to Provide basic data for thermal system of marine engine. this work performs an experimental study of heat transfer in a square channel with one rib-roughened wall under sin91e mode of reciprocating oscillation. A selection of heat transfer measurements illustrates the manner by which the reciprocating channel with two opposite heating walls has the higher heat transfer Performance than with four heating wall.

• ETRI Journal
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• v.46 no.3
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• pp.421-431
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• 2024

In this study, a direct position tracking method for non-circular (NC) signals using distributed passive arrays is proposed. First, we calculate the initial positions of sources using a direct position determination (DPD) approach; next, we transform the tracking into a compensation problem. The offsets of the adjacent time positions are calculated using a first-order Taylor expansion. The fusion calculation of the noise subspace is performed according to the NC characteristics. Because the proposed method uses the signal information from the previous iteration, it can realize automatic data associations. Compared with traditional DPD and two-step localization methods, our novel process has lower computational complexity and provides higher accuracy. Moreover, its performance is better than that of the traditional tracking methods. Numerous simulation results support the superiority of our proposed method.

• The Journal of Korean Society for School & Community Health Education
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• v.8 no.1
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• pp.43-54
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• 2007

This study aimed at investigating the level of high school students' entrance exam stress and mental health first and also investigating if the entrance exam stress and mental health are related to gender, grade, character type, parenting style and economic status. This is expected to be used as a fundamental data for the development of health education program on high school students' stress and diagnosis of their mental health. To achieve those goals above, the questionnaire was used and the sample consisted of 600 students from general high schools in a large city, C and in a smaller city, A in Chungnam province through questionnaire and the conclusion, which was based on 582 proper questionnaires from the 600 questionnaires, through variable analysis, correlation analysis and multi-regression, is below. First, according to the information provided by respondents, the result showed the relationship between those background variables and the entrance exam stress and mental health level. As the students are more introverted and the parenting style is more authoritative, the entrance exam stress is higher and the mental health level is higher as the parenting style is more authoritative and the economic status is lower. In gender, the entrance exam stress level was high for male students in regard to parents pressure. For female students, it was due to the insufficient free time. In test performance, the good grade group showed high stress level when they don't have enough free time and the poor grade group showed high stress level when they have test tension and poor test performance. In character style, the introverted group showed high stress level in future uncertainty. In parenting style, the authoritative group showed significantly high level in all four sub-factors and there is no significant relationship with the stress level and economic statue. Female students reported higher mental health level than male students in somatization and depression. In academic achievement, the poor grade group showed high level in obsession, fear-anxiety and psychotism. In character style, the introverted group showed high level in sensitivity towards others and depression. And in parenting style, the authoritative group is higher in 9 sub-factors than the other two groups in the factor, economic status. The lower economic status group showed high mental health problem level in this order; in obsession, sensitivity towards others, depression, paranonia and psychotism. Second, the results revealed that there is a significant difference among the groups after comparing and analyzing the relationship between the mental health level according to the three groups, the first, second and third group divided by the degree of entrance exam stress. And the higher the entrance exam stress is, the higher the mental health problem level is. Verification showed that there was obvious difference among the groups. the entrance exam stress was positively correlated with the mental health level. The lack of free time, future uncertainty, test anxiety/poor test performance and parents pressure, these factors, in that order, were correlated with the mental health level. when the prediction variables which influenced on mental health are analyzed, test-anxiety/poor test performance was found to be related to mental health most. And after the factor, test-anxiety, future uncertainty and the lack of free time were listed(ranked), however results did not show any correlation with parents' pressure.

• Journal of Korean society of Dental Hygiene
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• v.16 no.4
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• pp.601-607
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• 2016

Objectives: The purpose of the study is to investigate the cardiopulmonary resuscitation(CPR) knowledge and performance in the dental hygiene students in Gyeongju. Methods: A self-reported questionnaire was completed by 106 dental hygiene students in Gyeongju. The questionnaire consisted of CPR knowledge and performance, and was collected from April 4 to 12. The data were analyzed using SPSS version 18.0 by t-test, correlation analysis, ANOVA, and multiple regression analysis. Results: The average age of the subjects was 20.6 years and 97.2% were female students. The students did not experience the emergency situation(96.2%). Approximately half of the students received CPR education(51.9%), but they did not have the CPR certificate(94.3%). There was a significantly statistical correlation between the CPR knowledge and performance(p<0.01). The CPR knowledge was proportional to the CPR performance skill. The CPR knowledge (p<0.05) and performance (p<0.01) showed a statistical difference by the grade of the students. The CPR knowledge of the senior students was higher than that of the freshmen and sophomore. The CPR knowledge (p<0.01) and performance (p<0.01) showed a statistical difference by the education experience. The CPR education provided the students with CPR knowledge and performance. Conclusions: In order to promote and maintain CPR knowledge and performance on dental hygiene student, it should be reinforced the more systematic training program which can be repeatedly evaluated and retrained than the present. In addition, a follow-up study will also be needed for the student and clinical dental hygienist.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.322-334
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• 2012

The purpose of this paper is to explain and identify how service trust about enterprise of internal employees influence on management performance by investigating relationships between service trust in internal organization of enterprise, job commitment, customer service behavior, management performance. A survey study was conducted to collect the data with sales forces of at domestic major pharmaceutical companies. Analysis of structural equation modeling with AMOS 18.0 was performed to test the research hypothesis. The results of the study are as follows: service trust in internal organization of enterprise are positively associated on both job commitment and management performance, but it was negatively associated on customer service behavior. Job commitment was positively associated on customer service behavior but it was not influences on management performance. And customer service behavior was positively associated on management performance. Therefore, service trust in internal organization of enterprise was direct influences on management performance and it was also effects on through job commitment and customer service behavior. To sum up, if employees are devote themselves in work of their organization, service behavior on their customer of employees will be higher, and then management performance will be achievement. So, it have to reinforce job commitment on employees in order to achievement high performance of management through sales.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.182-189
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• 2015

The purpose of this study was to investigate the relationship between degree of satisfaction and experience on performance in accordance with the characteristics for the dental hygiene students. Dental hygiene students to 480 people from November to December 2014 and analyzed by conducting a survey. The higher grade students were more satisfied with the degree of satisfaction on experience for clinical test performance and clinical practice organization rather than the lower grade students. Also, the degree of satisfaction on major for the higher grade students has been shown as relatively higher than the lower grade students. The factors that affecting the experience for clinical performance and the degree of satisfaction for clinical practice were shown as grade, satisfaction for major and period for practice. In order to enhance the degree of satisfaction on the clinical performance for students, it should be established the system for practice management considering the characteristics of clinical practice by relevant organizations. Also, the dental hygienist who is responsible for dental education should manage his/her practice for students actively. Meanwhile, the practice organization should improve and update the content of education through the consistent alliance with colleges continuously.