• Quality Improvement in Health Care
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• v.25 no.2
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• pp.16-25
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• 2019

Purpose:The healthcare system of South Korea is at the extreme of the dispersed system. Few regulations limit patients from directly visiting higher-level medical institutions for primary care sensitive conditions. As a result, similar to local clinics, general and tertiary teaching hospitals also provide diverse primary care services. Our study aimed to examine the general public's perceptions of their primary care performance. Methods: Face-to-face surveys were conducted with 1000 adults who were living in South Korea with the aid of a questionnaire that included the Korean Primary Care Assessment Tool (KPCAT). The KPCAT consists of five domains, which are the main indicators of primary care performance: first contact, comprehensiveness, coordination, personalized care, and family/community orientation. One-way analysis of variance and post hoc tests were used to compare the KPCAT scores across the three types of medical institutions. Results: Domain-wise analyses revealed two different patterns. With regard to first contact and its subdomains, the highest and lowest scores emerged for local clinics and tertiary teaching hospitals, respectively. However, the other four domain scores were significantly lower for local clinics than for the other two types of medical institutions. Conclusions: Local clinics were perceived to be medical institutions that are responsible for providing primary care. However, the general public perceived only one domain of their primary care to be superior to that of the other two types of medical institutions: first contact. National efforts should be taken to strengthen their other four domains of primary care by training their workforce and providing appropriate incentives.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.425-438
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• 2021

The purpose of this study is to analyze local cultural festivals hosted contact-free in the corona era and to suggest the direction for sustainable festivals in the post-corona era. To this end, by analyzing the cases of well-known festivals held contact-free in 2020 and 2021, we tried to get implications for the festivals in the post-corona era from there. As a result of this study, contact-free festivals had the following characteristics. First, the on-tact method, which produces and transmits a video or allows interaction through real-time participation, was prominent. Second, in order to compensate for the shortcomings of the contact-free method, various efforts have been made to enable on-tact experience by making and delivering experience kits in the case of experiential elements of the festival in advance. Third, communication was secured through real-time comments, and fourth, products were sold through the Internet and live commerce channels, and a certain effect was obtained. In particular, in the case of online festivals, there is a problem of loss of the sense of place of the festival, but there are cases of online festivals with more participation than offline festivals. It is judged that the problem of how to achieve this will become a reference material for the future development of contact-free festival contents.

• Tribology and Lubricants
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• v.6 no.1
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• pp.99-107
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• 1990

Most of machines and structures contain the elements which contact each other directly. When these elements subjected to vibration or repeated load, local relative movement occurs between the elements in contact which results in, a kind of wear. In order to know the factors which govern fretting, we have to analyze the phenomenon of microslip which causes fretting by using a general and efficient method from a viewpoint of contact mechanics. Based on the results of analysis, it is necessary to propose the way of minizing fretting which is one of the most significant surface failure. In this report, a general and efficient algorithm is applied to analyze the contact problem of the bolted joint, which is one of the typical elements damaged by fretting, with ratios of plate thickness, the ratios of Young's moduli, the ratios of the plate thickness to bolt radius varied. Finally, the ways of minizing fretting for the boked joint are suggested.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.229-230
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• 2002

This paper presents the hot spot behaviors on the rubbing surface of ventilated disk brake by using finite element method. The depth of asperities on the rubbing surface is usually $2-3\;{\mu}m$ so the real contact area is microscopically. Non-uniform contacts between the disk and the pads lead to high local temperatures, which may cause the material degradation, and develops hot spots, thermal cracking, and brake system failures at the end. High contact asperity flash temperatures in rubbing systems, which is strongly related to the hot spot. It was generally known that high temperature over about $700^{\circ}C$ may form martensite on the cast iron which is material for automotive disk brakes. In this paper, the contact stress, temperature distribution and strain have been presented for the specific asperities of real contact area microscopically by using coupled thermal-mechanical analysis technique.

• Tribology and Lubricants
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• v.21 no.6
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• pp.289-295
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• 2005

Most machine element, such as gears and bearings, are operated in the mixed lubrication region. Contact between two asperities has an effect on machine life by increasing local pressure. To estimate fatigue life exactly, asperity contact should be considered as a factor of fatigue life because this happening produce friction, abrasion and make flash temperature. In this paper, asperity contact is considered as a result of film breakdown when lubricant pressure is not enough to separate two asperities. Contact pressure is calculated to asperity overlap region and added to lubricant pressure. For this model, numerical procedure is introduced and the result on surface roughness and velocity for wheel bearing is presented. Results of EHL analysis for wheel bearing show that asperity contact is occurred at the edge ofEHL conjunction where has a insufficient lubricant pressure to separate two surface.

• Tribology and Lubricants
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• v.19 no.5
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• pp.268-273
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• 2003

This paper presents hot spot behaviors on the rubbing surface of disk-pad type brake by using coupled thermal-mechanical analysis technique. The height of micro-asperity on the rubbing surface is usually 2∼3 ${\mu}$m in practical disk brakes. Non-uniform micro-contacts between the disk and the rigid friction pads lead to high local temperature distributions, which may cause the material degradation, and develop hot spots, thermal cracks, and brake system failure at the end for a braking period. The friction temperatures on the rubbing surface of disk brakes in which are strongly related to the hot spot and thermal related wears are rapidly concentrated on the micro-contact asperities during braking. The computed FEM results show that the contact stress, friction induced temperature and thermal strain are highly concentrated on the rubbing micro-contact asperities even though the braking speed and force are small during the braking period. This hot spot may directly produce the slippage and various thermal wears on the brake-rubbing surface.

• Tribology and Lubricants
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• v.13 no.3
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• pp.48-55
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• 1997

The ball bearing with thin-section raceways which is much lighter than other conventional bearings used in most modem passenger cars and small tracks. The important design parameters of this bearing is the groove radius of raceways, the diametral clearance, the free contact angle and so on. The optimal value of these parameters were determined by considering the dynamic load capacity, the contact angle and the calculated fatigue life. The contact angle between a ball and raceways was calculated by considering the local contact deformation and the structural deformation of thin-section raceways which was estimated by FEM. The raceways were made by means of the press-forming process. The fatigue life tester was designed and manufactured. The fatigue life test was executed and the reliability of this bearing was confirmed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.616-621
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• 2005

Most machine element, such as gears and bearings, are operated in the mixed lubrication region. Contact between two asperities has an effect on machine life by increasing local pressure. To estimate fatigue lift exactly, asperity contact should be considered as a factor of fatigue liff because this happening produce friction, abrasion and make flash temperature. In this paper, asperity contact is considered as a result of film breakdown when lubricant pressure is not enough to separate two asperities. Contact pressure is calculated to asperity overlap region and added to lubricant pressure. For this model, numerical procedure is introduced and the result on surface roughness and velocity for wheel bearing is presented. Results of EHL analysis for wheel bearing show that asperity contact is occurred at the edge of EHL conjunction where has a insufficient lubricant pressure to separate two surface.

• Journal of the Optical Society of Korea
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• v.1 no.2
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• pp.94-99
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• 1997

In this paper, we calculate the four coefficients for the quantum theory of multiwave mixing including a local-field correction resulting from dipole-dipole interactions. We make contact with the semiclassical calculations of probe absorption and four-wave-mixing coupling coefficients, and illustrate the effects of local field corrections on resonance-fluorescence and coupled-mode-fluorescence spectra. The method uses the hybrid quantum-Langevin-equation master-equation approach of An and Sargent.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.7
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• pp.559-564
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• 2016

The objectives of this paper are to develop a finite element analysis model to analyze press-fitted and bending load conditions in a press-fitted assembly, and propose a hub shape optimization method to minimize contact pressure near the shaft contact edge. Numerical asymmetric-axisymmetric finite element models have been developed to predict contact stress on press-fitted shafts. The global optimization method, genetic algorithm, local optimization method, and sequential quadratic programming were applied to a press-fitted assembly to optimize the hub contact edge geometry. The results showed that the maximum contact pressure with the optimized hub shape decreased more than 60 % compared to conventional hubs and the maximum contact stress affecting fatigue life was reduced about 47 %. Hub shape optimization can be useful to increase the load capability of press fits in terms of wear and fatigue behavior.