• Journal of the Korea Convergence Society
• /
• v.9 no.2
• /
• pp.1-6
• /
• 2018

In this study, the investigation results of conducted and radiated emission for DC/DC converter circuit applied in electric vehicles are presented. A frequency spreading circuit was used to improve the EMI characteristics of a power converter designed by using MPQ4433 chip. The frequency spreading circuit using a TLV3201 chip was designed and applied to the power converter. A PCB was fabricated based on the EMI minimization procedures and simulated and measured results were presented for the far-field and near-field conducted and radiated emissions using the fabricated circuit. The measurement were done as CISPR 25 standardized test procedures. It is clearly showed that the EMI characteristics were improved 20% in case frequency spreading was applied. The EMI reduction technique using the frequency spreading proposed in this study was first applied to the design of power converter module for automobile. It is expected that the method presented here can be effectively used for EMI improvement in the future.

• Journal of Technologic Dentistry
• /
• v.33 no.1
• /
• pp.79-92
• /
• 2011

Purpose: This study is to present substantial data for the development of practicable health related programs with which the dental technicians can enjoy better quality of life. To this end, we have surveyed the self-reported psychosomatic symptoms of the dental technicians in Korea and figured out their current health problems. Methods: Out of the random selection of the registered dental offices of Dental Technicians in Korea, 2,000 working dental technicians were asked to fill out the questionnaire from January 19 to April 30, 2009. We collected the 1,525 sheets of the questionnaire and took frequency analysis, t-test, analysis of variance and structural equation modeling using SPSS Win 12.0 and AMOS program. Results: Concerning the modes of the subjects' appealing of their psychosomatic self-symptoms, scale point of the mental health turned out 18.68, which is higher than the physical health that scored 17.28. In the case of the results from the standardized scores of the sub items, scale point of aggressiveness scored the highest(20.14), whereas that of mouth and annus scored the lowest (15.29). Additionally, the overall satisfaction rates of the health related quality of life was 67.89. Regarding the health related quality of life, self reported mental symptoms(-.736) was more influential than physical symptoms(0.29). Conclusion: The psychosomatic self reported symptoms of the dental technicians proved higher than other occupations, whereas health related quality of life was very low. Consequently, it seems vital to lessen the mental symptoms and the sub items concerned.

• Journal of Korean Academy of Nursing
• /
• v.50 no.4
• /
• pp.554-570
• /
• 2020

Purpose: This study aimed to develop and test a structural equation model of health-related quality of life among older women following bilateral total knee replacement based on a literature review and Wilson and Cleary's model of health-related quality of life. Methods: One hundred ninety three women who were diagnosed with osteoarthritis, were older than 65 years, and were between 13 weeks and 12 months of having a bilateral total knee replacement were recruited from an outpatient clinic. Data were collected from July 2017 to April 2018 using a structured questionnaire and medical records. Data were analyzed using SPSS/WIN 22.0, AMOS 22.0, and Smart PLS 3.2.4. Results: The fitness of the hypothetical model was good, with coefficients of determination (R²) ranging between .28 and .75 and predictive relevance (Q²) between .26 and .73. The standardized root mean square residual of the model fit indices for the hypothetical model was .04; which explained 64.2% of physical and 62.5% of mental health-related quality of life. Self-efficacy, symptom status, functional status, and general health perceptions had a significant direct effect on physical health-related quality of life, while social support, symptom status, and general health perceptions had a significant direct effect on participants' mental-health-related quality of life. Conclusion: To improve the physical and mental quality of life of older women who receive bilateral knee replacement, nursing-based intervention strategies that reduce symptoms, improve functional status, and increase health perceptions, self-efficacy, and social support are needed. The most important factor is the symptom status.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.3
• /
• pp.295-302
• /
• 2007

Statement of problem. Fracture of the tooth-colored superstructure material is one of the main prosthetic complications in implant-supported prostheses. Purpose. The purpose of this in vitro study was to compare the fracture strength between the cement-retained implant-supported metal-ceramic crowns and the indirect composite resinveneered metal crowns under the vertical compressive load. Material and methods. Standard implants of external type (AVANA IFR 415 Pre-mount; Osstem Co., Busan, Korea) were embedded in stainless steel blocks perpendicular to their long axis. Customized abutments were fabricated using plastic UCLA abutments (Esthetic plastic cylinder; Osstem Co., Busan, Korea). Thirty standardized copings were cast with non-precious metal (Rexillium III, Pentron, Walling ford, Conn., USA). Copings were divided into two groups of 15 specimens each (n = 15). For Group I specimens, metal-ceramic crowns were fabricated. For Group II specimens, composite resin-veneered (Sinfony, 3M-ESPE, St. Paul, MN, USA) metal crowns (Sinfony-veneered crowns) were fabricated according to manufacturer's instructions. All crowns were temporary cemented and vertically loaded with an Instron universal testing machine (Instron 3366, Instron Corp., Norwood, MA, USA). The maximum load value (N) at the moment of complete failure was recorded and all data were statistically analyzed by independent sample t-test at the significance level of 0.05. The modes of failure were also investigated with visual analysis. Results. The fracture strength of Sinfony-veneered crowns ($2292.7{\pm}576.0N$) was significantly greater than that of metal-ceramic crowns ($1150.6{\pm}268.2N$) (P < 0.05). With regard to the failure mode, Sinfony-veneered crowns exhibited adhesive failure, while metal-ceramic crowns tended to fracture in a manner that resulted in combined failure. Conclusion. Sinfony-veneered crowns demonstrated a significantly higher fracture strength than that of metal-ceramic crowns in cement-retained implant-supported prostheses.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.1
• /
• pp.181-199
• /
• 2000

In this paper, we implemented and tested MPOA(MutiProtocol Over ATM) standardized in ATM Forum, which provides service for various layer 3 protocols as well as legacy LAN applications over ATM networks. The functions of MPCs(MPOA Clients) and MPSs(MPOA Servers) which are the components in MPOA systems are implemented. MPCs are located at the edge device and MPOA hosts and MPSs exist in routers. The implemented MPCs have the functions such as exchances of primitives between an LEC(LAN Emulation Client) and an MPC, management and maintenance of Egress/Ingress cache, default transmission through LECs and shortcut transmission. Assuming that routing, convergence and NHRP(Next Hop Resolution Protocol) functions exist in routers, the implemented MPSs have the functions such as exchanges of primitives between an LEC and an MPC, conversion and exchanges of frames between MPOA and NHRP, and management and maintenance of Egress/Ingress cache. All of the possible scenarios are made up to test whether they run correctly. The implemented system is tested by simulation according to the scenarios.

• Journal of The Korean Association For Science Education
• /
• v.16 no.4
• /
• pp.410-416
• /
• 1996

The purpose of this study is to determine which variable is the best predictor of students' science-related attitudes. Three influential variables were tested : students' science achievement. students' science process skills, and teachers' attitudes toward science. This study has been made on the basis of questionnaire from 205 1st graders in 5 different middle schools in Seoul. The instruments used for measuring attitudes were TOSRA and the questionnaire developed by Sung-Jae Pak(1980). The instrument used for measuring science process skills was a standardized test developed by Youne-Woo Lee(1989). The results was analyzed by multiple-regression in the statistical packages SPSS/PC+. The major findings of this study are as follows. 1. The mean score of students' science-related attitudes was 66.8, and there was no significant difference according to gender of students and teachers(p> .05). 2. The mean score of students' science process skills was 61.1, and there was no significant difference according to gender of students and teachers(p> .05). 3. Students' science process skills was the best predictor of students' science-related attitudes among three variables(R=0.3102, p< .05). 4. The subjects were divided into 2 groups by students' science achievement. In the high score group, students' science achievement was the best predictor of students' science-related attitudes (R=0.3406, p<.05). And in the low score group, none of the variables was related to students' science-related attitudes (p> .05). 5. In students who has a male science teacher, students' science process skill was the best predictor of students' science-related attitudes (R=0.3220, p<.05). And in students who has a female science teacher, students' science achievement was the best predictor of students' science-related attitudes (R=0.3480, p<.05).

• Structural Engineering and Mechanics
• /
• v.55 no.4
• /
• pp.765-784
• /
• 2015

Connections are usually designed either as pinned usually associated with simple construction or rigid normally is associated with continuous construction. However, the actual behaviour falls in between these two extreme cases. The use of partial strength or semi-rigid connections has been encouraged by Euro-code 3 and studies on semi-continuous construction have shown substantial savings in steel weight of the overall construction. Composite connections are proposed in this paper as partial or full strength connections. Standardized connection tables are developed based on checking on all possible failure modes as suggested by "component method" for beam-to-column composite connection on major axis. Four experimental tests were carried out to validate the proposed standardised connection table. The test results showed good agreement between experimental and theoretical values with the ratio in the range between 1.06 to 1.50. All tested specimens of the composite connections showed ductile type of failure with the formation of cracks occurred on concrete slab at maximum load. No failure occurred on the Trapezoidal Web Profiled Steel Section as beam and on the British Section as column.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.13 no.3
• /
• pp.43-60
• /
• 2005

In september 2004, a new pilot certificate scheme referred to as Sport Pilot Certificate was declared official and standardized in the US. The designation of Light-sport aircraft and the details of the relevant pilot certificate policy was announced out of the perception that a new regulation is required to be applied whereby the limitations on the manufacturing process enhancements and current aviation rules are considered the triggering factors. US Federal Aviation Regulation retains a comprehensive range of airworthiness certificates and aircrafts are managed systematically in accordance with FAR 21, 103. The airworthiness are further segregated into sub categories, which allows differentiated management. Korean Aviation Law classify aircraft into five different categories and powered air vehicle that weighs more than 150kg(19liters fuel capacity) for one seat, 225kg for two seats(38liters fuel capacity) while the systems that fall under a specific mass threshold level are known as ultralight vehicle. The research discusses the policy of the sport pilot certificate and the light-sport aircraft ratings announced official by the Federal Aviation Administration in an intuitive fashion with the analysis of the operations providing the evidence as to the viability of adopting the policy in local grounds. Based on the findings, the report discusses the case for introducing the light-sport aircraft and make recommendation on a strategy of applying the policy in Korea with respect to the pilot certificates, safety agenda, and the written test for the pilot certificate, and operating efficiency.

• Research in Community and Public Health Nursing
• /
• v.11 no.2
• /
• pp.321-332
• /
• 2000

The purpose of this study was to test the hypothetical model designed to explain nursing students' perceived stress, coping levels, and stress outcomes. This hypothetical model was based on the Kim. Jung Hee(l987)' s stress model and stress-related literature. Exogenous variables were self-efficacy. hardiness. social support. and exercise. Endogenous variables were stress perception. coping levels. and stress outcomes. Empirical data for testing the hypothetical model consisted of 205 nursing students. SAS PC Program and LISREL 8.12a program were used for descriptive statistics and linear structural relationship(LISREL) modeling. The results were as follows. 1) The overall fit of the hypothetical model to the data was good( $x^2$=78.41(p=0.010), $x^2$/ df=1.50. RMSEA=0.05, standardized RMR= 0.05, GFI=0.95, AGFI=0.91, NNFI=0.90, NFI=0.94). 2) The results of statistical testing of the hypotheses were as follows. (1) As expected. self-efficacy had a significant effect on stress perception. But. hardiness. social support, and exercise did not have a significant effect on stress perception. Self-efficacy, hardiness. social support, and exercise explained 12% of the total variance of stress perception. (2) As expected, self-efficacy, hardiness, social support, exercise, and stress perception had a significant effect on coping behavior, Self-efficacy, hardiness, social support, exercise, and stress perception explained 53% of the total variance of coping behavior. (3) As expected, stress perception and coping behavior had a significant effect on stress outcomes. Stress perception and coping behavior explained 84% of the total variance of stress outcomes. In conclusion, the hypothetical model of this study was confirmed in explaining and predicting stress perception, coping levels, and stress outcomes in nursing students. And these findings suggest the need to develop nursing intervention to enhance self-efficacy, hardiness, social support, and exercise to decrease the harmful outcomes of stress.

• Korean Journal of Construction Engineering and Management
• /
• v.10 no.6
• /
• pp.88-98
• /
• 2009

Construction industries have increasingly utilized Building information Modeling (BIM) technologies. Interoperability - the capability for BIM data to run from one computer application to another in the life cycle of a project has become one of the principal research areas. Enhancing interoperability inevitably requires information structures that are standardized throughout the construction industries. As a candidate of the data exchange standard, Industry Foundation Classes (IFC) has been developed and several researches recently performed to measure its richness of digital data exchange. But doubts have been brought up whether IFC meets a sufficient level of interoperability since the research result revealed a number of cases of information misrepresentation and loss. This research presents the lessons learned from the interoperability tests of three widely used 3D design applications including Graphisoft's Archicad, Autodesk's Revit, and Bentley's Bentley Architecture. One building's architectural and structural design data were modeled with the three tools and exchanged through IFC respectively for interoperability test.