• Advances in nano research
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• v.14 no.5
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• pp.435-442
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• 2023

Sports activities, including playing tennis, are popular with many people. As this industry has become more professionalized, investors and those involved in sports are sure to pay attention to any tool that improves athletes' performance Tennis requires perfect coordination between hands, eyes, and the whole body. Consequently, to perform long-term sports, athletes must have enough muscle strength, flexibility, and endurance. Tennis rackets with new frames were manufactured because tennis players' performance depends on their rackets. These rackets are distinguished by their lighter weight. Composite rackets are available in many types, most of which are made from the latest composite materials. During physical exercise with a tennis racket, nanocomposite materials have a significant effect on reducing injuries. Materials as strong as graphite and thermoplastic can be used to produce these composites that include both fiber and filament. Polyamide is a thermoplastic typically used in composites as a matrix. In today's manufacturing process, materials are made more flexible, structurally more vital, and lighter. This paper discusses the production, testing, and structural analysis of a new polyamide/Multi-walled carbon nanotube nanocomposite. This polyamide can be a suitable substitute for other composite materials in the tennis racket frame. By compression polymerization, polyamide was synthesized. The functionalization of Multi-walled carbon nanotube (MWCNT) was achieved using sulfuric acid and nitric acid, followed by ultrasonic preparation of nanocomposite materials with weight percentages of 5, 10, and 15. Fourier transform infrared (FTIR) and Nuclear magnetic resonance (NMR) confirmed a synthesized nanocomposite structure. Nanocomposites were tested for thermal resistance using the simultaneous thermal analysis (DTA-TG) method. scanning electron microscopy (SEM) analysis was used to determine pores' size, structure, and surface area. An X-ray diffraction analysis (XRD) analysis was used to determine their amorphous nature.

• Korea Journal of Hospital Management
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• v.28 no.2
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• pp.9-20
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• 2023

Purpose: This study classified the actual functions of geriatric hospitals and examined the differences in their characteristics, in order to provide a basis for discussions on defining the functions of geriatric hospitals and how to pay for care. Methodology: This study used various administrative data such as health insurance data and long-term care insurance data. Cluster analysis was used to categorize geriatric hospitals. To examine the validity of the cluster analysis results, we conducted a discriminant analysis to calculate the accuracy of the classification. To examine cluster characteristics, we examined structure, process, and outcome indicators for each cluster. Findings: The cluster analysis identified five clusters. They were geriatric hospitals with relatively short stays for cancer patients(cluster 1; cancer patient-centered), geriatric hospitals with relatively large numbers of patients using rehabilitation services(cluster 2; rehabilitation patient-centered), geriatric hospitals with a high proportion of relatively severe elderly patients(cluster 3; severe elderly patient-centered), geriatric hospitals with a high proportion of mildly ill elderly patients with various conditions(cluster 4; mildly ill elderly patient-centered), and geriatric hospitals with a significantly higher proportion of dementia patients(cluster 5; dementia patient-centered). The largest number of geriatric hospitals were categorized in clusters 4 and 5, and the structure and process indicators for these clusters were generally lower than for the other clusters. Practical Implications: We have confirmed the existence of geriatric hospitals where the medical function, which is the original purpose of a geriatric hospital, has been weakened. It has been observed that the quality level of these geriatric hospitals is likely to be lower compared to hospitals that prioritize enhanced medical functions. Therefore, it is suggested to consider the conversion of these geriatric hospitals into long-term care facilities, and careful consideration should be given to the review of care-giver payment coverage.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.214-222
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• 2022

It is important to realize employment equality to fulfill corporate social responsibility. The most suitable indicator for assessing its performance is the gender wage gap. Korea is considered the country with the most severe gender wage gap among OECD member countries, however, studies on the gender wage gap have been mainly attempted to explain in terms of the structure of the labor market, government policies, etc. This study focus on the characteristics of CEO and HR systems among the characteristics of organizations affecting the gender wage gap. The management philosophy sets the direction of organizational decision-making and activates the system. In addition, the HR system enables fair and objective organizational management for members through rules and procedures. However, even in organizations seeking rationalization, minority people may experience discrimination. Moreover, the rational HR system may act as a mechanism to justify discrimination, contrary to existing intentions. This study proposes that in order for the rational HR system to work positively, it must be based on the management philosophy. In other words, it is intended to derive a mechanism that can alleviate the gender wage gap from the integrated perspective of the characteristics of the CEO and the rational HR system. In particular, it aims to provide specific implications for how the organization should operate the HR system by examining the gender wage gap based on internal factors of companies that utilize manpower.

• Journal of the Korean Geotechnical Society
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• v.24 no.1
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• pp.51-59
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• 2008

In this study, cyclic shear characterics of sand-clay mixtures were analyzed. In order to perform cyclic triaxial tests on sand clay mixtures, natural clays with activity and silica sand were mixed variously to reproduce soils with wide range of grain size compositions. Test specimens with various fines contents were prepared by the moisture compaction and pre-consolidation methods, while paying attention to the void ratio expressed in terms of the sand structure and clay structures, and undrained cyclic shear tests were performed. In the test results, cyclic shear strength decreased with increasing of sand granular void ratio below 20% of fine contents. When the granular void ratio of the test specimen exceeded the maximum void ratio of the silica sand, the clay matrix dominated the soil structure, and soil structures were not influenced by compaction energy. It was observed that, the matrix structure of the coarse particles has great effect on the undrained cyclic shear strength characteristics for sand-clay mixtures, and therefore, it is more appropriate to pay more attention to the density of the sand structure, rather than to the fines content.

• Korea journal of population studies
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• v.21 no.2
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• pp.58-82
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• 1998

It is usually proposed that job security of old age workers is hampered by the structure of wage increasing with age. This paper sets forth a model to comprehend the characteristic of the old age workers' labor market and policy implications derived from it. In order to stimulate demand for old age workers, policy initiatives should be taken as follows : the wage criteria should be simplified which apply differently from one institution to other; incentives relatively favorable for employing old age workers' in manufacturing sector should be also given to service sectors; employment subsidy or other tax incentives should be given for labor contract after the retirement age; licensing and evaluation system for job ability should be introduced based on occupation & job analysis. To lower the reservation wage of workers, mortgage loan for house and long-term low interest loan for tuition fees should be developed together with stabilization of housing cost. Wedding culture which requires high expense should be amended. Above all, it is necessary to install reasonable social security system. Policy orientation should also pay attention to reduce labor supply of the old aged via aiding old age workers' firm opening and voluntary civil service together with developing various honor programs for members of civil corps.

• Korea Journal of Hospital Management
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• v.6 no.1
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• pp.1-17
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• 2001

According to the increase of the proportion of aged people, the medical demand for a senile chronic disease has been increased; therefore, aged people call for a geriatric hospital for special geriatric medical service. The main purpose of this study was to analyze the general characteristics and financial status of geriatric hospitals. For the study, a questionnaire was designed and sent to the geriatric hospitals to fill out the patient statistics, number of headcount by department, etc. to find out the stability, profitability, activity and so on financial statements of the hospitals were analyzed. The major findings of this study were as belows. 1. The ratio of the medical expenses to the revenue of the geriatric hospitals is much lower than acute care hospitals. But the probability of bankruptcy is higher due to the high ratio of the liabilities therefore it is required to stabilize the financial position by donating more money. 2. Government budget for the elderly people is not enough. To support the geriatric hospitals by going subsides, government should increase the budget. 3. Portion's of the patient of the geriatric hospitals are government support patient. Since the government doesn't pay the medical charges quickly, geriatric hospitals have a serious cash flow problem. Therefore, it is required that government is to prepay the bill. 4. Since geriatric hospitals treat elderly patient and most patients are government support patients, geriatric hospitals can be said to operate under the strict. 5. When we introduce the daily medical charge, the self-liability will be reduced on approximately 50% of current. This affection will bring a huge progressing financial structure to the medical profit of the geriatric hospital, and also patient family will feel less economical burden.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1157-1161
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• 2011

Parametric study has been conducted to calculate the capacity of vacuum pump system that will be used to maintain the pressure of the tube system under atmosphere level. Recently many railroad researchers pay attention to the tube train system as one of the super high speed transportation system. To achieve the ultra super high speed, the inside of tube system should be maintained the low pressure level. In the low pressure environment, it is well known that air resistance of train is drastically decreased. Vacuum pump system will be used to make the low pressure level of tube system, exhaust the leakage air and supplement additional vacuum pumping. Qualitative and quantitative study has been conducted to review the effects of major parameters concerned with the capacity of vacuum pump system. As a results of these studies, we get the lump capacity of vacuum pump for various parameters. These results can be used to analyse the effects of the reduction of air resistance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.101-107
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• 2017

Over-break, which is excavated larger than planned line at tunnel excavation, is inevitable due to the nature of blasting. But regarding the bottom of the foundation, most of the domestic ordering organizations pay only 10 cm thick filled concrete when pouring concrete due to over-break. In accordance, the construction cost will increase greatly if all the depths of the designed over-break are filled only with concrete. When tunnel excavation occurs, concrete filling of 18 MPa(T = 100 mm) and 150 mm~237 mm auxiliary concrete layer and 240 mm concrete track(TCL) are applied to the upper part. The concrete is installed in an excessive amount of about 600 mm between the lower part of the rail and the tunnel rock bed. Therefore, in this study, it is necessary to analyze the concrete crack structure according to the depth of the existing tunnel and the modified tunnel section, and to evaluate the adequacy of the required thickness of the tunnel floor concrete for securing the crack stability of the concrete.

• Journal of Technologic Dentistry
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• v.13 no.1
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• pp.79-97
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• 1991

To improve the management of dental laboratory through the research on the actual condition, this study posed questions on 36 dental laboratories. The results are as follows : 1. The establishment of dental laboratory in Chunbuk was increased between in 1980 and 1986. Especially it has been more increased since 1989. According to the proportion of population the number of the dental laboratories in Chunbuk was much more than that of other provinces and took the first place in september 1990. 2. The ratio between the unlicensed dental technician and the licensed was 24.83% and 67.11% each . The former must be replaced by the licensed. And the latter ought to try to improve their culture and technique. 3. Overtime payment must be paid for those who work above eight hours. 4. It takes 5 days at a minimum for the production of dental prosthesis with both stability and esthetics. 5. Every Saturday afternoon, Sunday and national holiday must be free. 6. Bonus must be paid 600% a year at a minimum. The system of retirement allowance should be active. All dental technicians ought to be affliated with their labor union and medica insurance. 7. Such dental restoration as porcelain and crown and bridge prosthesis must by increased to a degree between 30% and 50% at a minimum and the reduction system of charge for a dental technique has to be abolished. 8. The general working conditions of dental laboratory, especially pay and working hour must be improved. 9. To advance the service improvement of dental treatment and the banishment of illegal one, the medical insurance of crown and bridge prosthesis must be generally practised. 10. Ill case of the staff cull:lloyulent of dental laboratory, minimem wage system must be observed. 11. Directing dentist system on the ertablisment of dental laboratory must be abelished or wholly improved.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.207-221
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• 2003

A hash chain is highly efficient, attractive structure to use in electronic cash. Previous systems using hash chain were, however, either credit-based vendor-specific cash or debit-based general-purpose cash which lacks efficiency due to double spending problem. In this paper, we propose a new divisible cash system using hash chain. This newly proposed cash is general-purpose, debit-based, anonymous, and offline. The efficiency of the system results from its capacity to pay variable amounts with no additional costs. A client always performs a single blind signature in the withdrawal phase, independent of the length of the chain. During payment, a client performs a single challenge-and-response or generates a single signature, independent of the amount paid. This system provides a new refund mechanism, which uses a refund ticket, that allows clients to refund the unspent part of the chain without revealing any connection to the spent part.