• 보건행정학회지
• /
• 제11권1호
• /
• pp.107-130
• /
• 2001

During the last year, we had a very severe situation with the strike of physicians working in medical facilities. From that time, many politicians and scholars insisted on the expansion of public hospitals to enhance the public role in the medical care sector. They think that private medical facilities work for profit motivation and that the high proportion of private to whole facilities is an obstacle to the public function of medical care under social insurance system. They found that one of the reasons for failing to prevent the physicians' strike was the high proportion of private facilities. Others insisted that the strike was not a good reason for the expansion of public hospitals. The physicians' strike was a very rare case, and it is not a good basis for generalization of the discussion of public hospitals. Last year almost all apprentice physicians in public facilities took part in the strike, and consequently the public hospitals also lost the role of public function. They view this increasing involvement of government in the medical sector as improper and the cause of inefficiencies. In this paper we review the debate over the expansion of public facilities. To clarify the debate, we review traditional criteria for the role of government in a market system and to apply these criteria to medical care. There are two traditional areas where government Is acknowledged to have a role in a market system: market imperfections and market failure. Where market imperfections and market failure exist, there may be a role for government. The justifications for government intervention are consumer protection and the existence of externalities. One of externalities is to provide medical care for the poor. The appropriate measures to provide medical owe to the poor can be sought in both demand and supply side subsidies. National health insurance is a method of demand subsidies and establishment of public hospitals is a method of supply side subsidies. Under the National Health Insurance System, the expansion of public hospitals is not an appropriate subsidy policy.

• 한국지반신소재학회논문집
• /
• 제18권3호
• /
• pp.79-88
• /
• 2019

본 연구에서는 도로노면 하부 지반에서 발생한 공동의 확장특성을 평가하기 위하여, 지하수주입 실험을 수행하였다. 즉, 공동체적에 비례한 일정량의 물을 단계별로 주입하고, 주입한 물이 배출됨에 따라 확대되는 공동을 모니터링 함으로써, 공동의 체적변화를 확인하였다. 실험결과, 지하수 주입에 따른 공동의 체적은 증가하다 수렴 또는 감소하는 경향을 나타냈다. 이는 지하수 주입 시, 공동이 확장되는 과정에서 주변의 이완된 지반이 일부 붕괴되거나 세립토가 주변 지반의 간극을 채우기 때문인 것으로 분석되었다. 또한 지하수 주입 단계에 따른 공동의 체적변화와 확장특성을 분석한 결과, 실험대상 공동은 횡방향으로 확장되는 것을 확인할 수 있었다. 그리고 지하수 유동에 따라 이완된 공동 주변지반이 붕괴되고, 붕괴된 토사가 공동하부의 지중으로 유실되는 과정이 반복됨으로써 공동이 확장되는 것으로 평가되었다.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 1998년도 제17회 KOSCI SYMPOSIUM 논문집
• /
• pp.139-154
• /
• 1998

Under certain circumstance, premixed turbulent flame can be treated as wrinkled thin laminar flame and its motion in a hydrodynamic flow field has been investigated by employing G-equation. Past studies on G-equation successfully described certain aspects of laminar flame propagation such as effects of stretch on flame speed. In those studies, flames were regarded as a passive interface that does not influence the flow field. The experimental evidences, however, indicate that flow field can be significantly modified by the propagation of flames through the volume expansion of burned gas. In the present study, a new method to be used with G -equation is described to include the effect of volume expansion in the flame dynamics. The effect of volume expansion on the flow field is approximated by Biot-Savart law. The newly developed model is validated by comparison with existing analytical solutions of G -equation to predict flames propagating in hydrodynamic flow field without volume expansion. To further investigate the influence of volume expansion, present method was applied to initially wrinkled or planar flame propagating in an imposed velocity field and the average flame speed was evaluated from the ratio of flame surface area and projected area of unburned stream channel. It was observed that the initial wrinkling of flame cannot sustain itself without velocity disturbance and wrinkled structure decays into planar flame as the flame propagates. The rate of decay of the structure increased with volume expansion. The asymptotic change in the average burning speed occurs only with disturbed velocity field. Because volume expansion acts directly on the velocity field, the average burning speed is affected at all time when its effect is included. With relatively small temperature ratio of 3, the average flame speed increased 10%. The combined effect of volume expansion and flame stretch is also considered and the result implied that the effect of stretch is independent of volume release.

• Steel and Composite Structures
• /
• 제22권1호
• /
• pp.1-12
• /
• 2016

Severe fatigue and noise problems of modular bridge expansion joints (MBEJs) are often induced by vehicle loads. However, the dynamic characteristics of single-support MBEJs have yet to be further investigated. To better understand the vibration mechanism of single-support MBEJs under vehicle loads, a 3D finite element model of single-support MBEJ with five center beams is built. Successive vehicle loads are given out and the vertical dynamic responses of each center beams are analyzed under the successive loads. Dynamic amplification factors (DAFs) are also calculated along with increasing vehicle velocities from 20 km/h to 120 km/h with an interval 20 km/h. The research reveals the vibration mechanism of the single-support MBEJs considering coupled center beam resonance, which shows that dynamic responses of a given center beam will be influenced by the neighboring center beams due to their rebound after the vehicle wheels depart. Maximal DAF 1.5 appears at 120 km/h on the second center beam. The research results can be utilized for reference in the design, operation and maintenance of single-support MBEJs.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.568-573
• /
• 2003

When a safety valve equipped in a nuclear power plant opens in an instant by an accident, a moving shock wave propagates downstream the valve, inducing a complicated unsteady flow field. The moving shock wave may exert severe load to the structure. So, to reduce the load acting on the wall of POSRV, a gradual opening of POSRV is adopted in general. In theses connections, a numerical work is performed to investigate the effect of valve opening time on the unsteady flow fields downstream of the valve. Compressible, two-dimensional Navier-Stokes equations are used with the finite volume method. The obtained results show that sharp pressure rise through moving shock tor the case of instant opening is attenuated by employing the gradual opening of valve. It is turned that the flows for the two cases of gradual valve opening time show the similar to that of highly under-expanded one in jet structure having expansion and compression waves and Mach stem. Also, comparing with the results for the two cases of opening time, the shorter the valve opening is, the pressure gradient at the downstream of the valve becomes softly.

• 보건행정학회지
• /
• 제10권1호
• /
• pp.57-94
• /
• 2000

Korea's social health insurance system was introduced in 1977, which has made a universal coverage possibly by July 1989. Korean government had pursued a single objective for the last decade to put the whole population under the coverage of medical security, and the objective was achieved within 12 years. The rapid accomplishment is primarily due to such factors as limited benefits, high copayment rate, low contributions as well as rapid economic growth. There are several sources of pressure for the implementation of social health insurance such as health professional group, labor unions, politicians, international organizations etc.. However it is important to look at the feasibility of social health insurance. Among other things, it is necessary to identify the administrative infrastructure of insurance system and to assess income for source of fund. As many developed countries, Korea began to apply health insurance to the employees of the large firms, and the expansion based on employment status. Thus the several funds system was inevitable according to the gradual expansion strategy. However many persons had criticized several funds system in respect with equity and efficiency aspects. In the short history of the Korean health insurance, whether one fund or sever or funds had been the most controversial issue. In Febrary 1999, the National Assembly passed the act of one fund system. From July 2000 separate funds will be unifed under new health insurance scheme. In this study we will analyze the policy making process on implementation, expansion and integration of health insurance system of Korea. And also analyse problems related to policy making.

• 해양환경안전학회지
• /
• 제17권2호
• /
• pp.173-178
• /
• 2011

선박에 사용되는 TEMA 열교환기 전열관의 확관 공정에서 발생되는 탄소성 응력과 변형량의 거동을 유한요소법으로 해석하였다. 열교환기의 관판 구명의 홈 깊이와 롤러 익스팬더의 작용압력을 변화시켜 해석한 결과, 전열관의 관판 구멍의 홈 깊이가 커지면 탄소성 압축응력은 감소하였고, 롤러 익스팬더 압력이 높을수록 관판 구멍의 홈 모서리 부분의 탄소성 응력이 증가되었다.

• 한국군사과학기술학회지
• /
• 제16권1호
• /
• pp.74-80
• /
• 2013

In this paper, we have proposed a vapor cycle refrigeration system as a cooling system to provide cooling air to the aircraft external reconnaissance stores. In the proposed vapor cycle system, receiver which prevents refrigerant from subcooling was eliminated and thermal expansion valve was replaced with electronic expansion valve. The vapor cycle refrigeration system is aimed to provide cooling air to the reconnaissance stores which is added to the aircraft in the form of external store. The wide temperature range of ambient air from the flight conditions can decrease the cooling performance and can make the refrigeration system unstable in low ambient temperature. Performance characteristics of the vapor cycle refrigeration system has been experimented under air conditions which is derived from the flight envelope. From the experiments, the vapor cycle refrigeration system has been proved to provide enough cooling air to the reconnaissance equipment and to be stable under all the flight conditions.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 1998년도 21세기 한반도 농업전망과 대책(한국작물학회.한국육종학회 공동주관 심포지움 회보)
• /
• pp.189-209
• /
• 1998

Food resources have been supplied more and more by crop land expansion, technological Improvement for higher crop yield, establishment of irrigation system, and input of fertilizers, chemicals and others, to sustain a world population increase currently about 6 billion. Food demand will be significantly increased in the 21st century due to population increases of 90 million per year and more consumption of meat with per capital income increase. But food production increase will be limited by difficulty of crop/irrigation land expansion and small or decreasing effectiveness of fertilizer use. Development of new techniques for higher yield per ha is only one way to meet future food demand increase. Optimistic prospect for food demand/supply balance was reported by FAO until 2010, and IFPRI until 2020. However, Worldwatch Institute warned world food supply will be less than expected demand by 500 million tons of cereal grains in 2030. It is necessary to establish a national plan to meet expected worldwide shortage of food resources in 21 century. What planning should be under taken to meet the upcoming century of food shortage in Korea whose food self-sufficiency rate is only $30{\%}$. It is recommended that (1) keep paddy field area as much as 1,100 thousand ha, (2) expansion of barley and wheat cultivation on all paddy area in winter season, (3) continue development of new technology to get international superiority of food resources produced in Korea, (4) expand nationwide the importance of food security under the current financial crisis encountered In Korea, and for food security in the future unified Korean peninsula.

• Geomechanics and Engineering
• /
• 제23권6호
• /
• pp.561-573
• /
• 2020

The creep and consolidation behaviors of clays subjected to thermal cycles are of fundamental importance in the application of energy geostructures. This study aims to numerically investigate the physical mechanisms for the temperature-triggered volume change of saturated clays. A recently developed thermodynamic framework is used to derive the thermo-mechanical constitutive model for clays. Based on the model, a fully coupled thermo-hydro-mechanical (THM) finite element (FE) code is developed. Comparison with experimental observations shows that the proposed FE code can well reproduce the irreversible thermal contraction of normally consolidated and lightly overconsolidated clays, as well as the thermal expansion of heavily overconsolidated clays under drained heating. Simulations reveal that excess pore pressure may accumulate in clay samples under triaxial drained conditions due to low permeability and high heating rate, resulting in thermally induced primary consolidation. Results show that four major mechanisms contribute to the thermal volume change of clays: (i) the principle of thermal expansion, (ii) the decrease of effective stress due to the accumulation of excess pore pressure, (iii) the thermal creep, and (iv) the thermally induced primary consolidation. The former two mechanisms mainly contribute to the thermal expansion of heavily overconsolidated clays, whereas the latter two contribute to the noticeable thermal contraction of normally consolidated and lightly overconsolidated clays. Consideration of the four physical mechanisms is important for the settlement prediction of energy geostructures, especially in soft soils.