• 설비공학논문집
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• 제29권4호
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• pp.175-184
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• 2017

With the improvement of living standards, the ventilation for the mitigation of indoor or outdoor air-pollution problems has recently attracted a lot of attention. Consequently, the ventilation for the supply of outdoor fresh air into a room is treated as an important building-design factor. The ventilation is generally divided into the forced and natural types; here, the former can control the ventilation rate by using mechanical devices, but it has the disadvantages of the equipment costs, maintenance costs, and noise generation, while the latter is applied to most workshops due to the absence of noise and the low installation and maintenance costs. In this experimental study, the ventilation performance of a typical rotating-type natural ventilator, which is called a "wind turbine," was investigated with the outdoor-wind velocity and the indoor/outdoor-temperature difference. From the experiment results, it was confirmed that the temperature difference of $10^{\circ}C$ corresponds to the ventilation driving force with an outdoor-wind velocity of 1.0 m/s. Additionally, the intake-opening area of a building also exerts a great effect on the ventilation rates.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 21세기 한반도 농업전망과 대책(한국작물학회.한국육종학회 공동주관 심포지움 회보)
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• pp.68-111
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• 1998

The structure of the Hanwoo (Korean Native Cattle) Industry remains very weak and vulnerable to the WTO/IMF system. Considering that the majority of cattle farmers are small sized, and that marketing systems are outdated and inefficient, rapid expansion of lower priced beef imports by WTO system and rapid increasing of production costs by IMF system would lead to the deprivation of a regular source of farm income and threaten the stability of rural life. Accordingly, the Hanwoo industry should be expanded in accordance with progress in the implementation of (1) programs for the structural adjustment and (2) measures to compensate for the loss. Efforts for lowering major production factor costs needs to continue, In order to increase the supply of calves at low cost, the programs of collective cow-calf farms should be expanded, thereby reducing the cost of calf purchase, which constitutes the largest share of Hanwoo production cost. Also, feedlot operations should be encouraged for small herd farms in order to achieve a substantial saving in beef production costs by integrated operations from calf production to cattle fattening. A substantial saving would also be made by collective purchase and distribution of various inputs through the cooperatives' channels. Extension services should be strengthened for cattle farm management, cattle care and feeding, prevention of cattle disease, etc. In order to minimize cash outlays for commercial mixed feeds, utilization of far by-products as feeds should be enhanced and production of forage crops productive of resources, such as land and rural labor, during the farm o(f-season, needs to be encouraged. Also, technological development for enhancing the nutritional value of farm by-products should be encouraged. Measures for successful segregation of the Hanwoo beef market should be implemented, thereby enhancing incentive for quality beef producers and protecting consumers willing to pay higher price for quality beef. For development of the Hanwoo industry, a considerable time frame would be required in order for (1) small livestock farmers to make a successful adjustment by staying in the enterprise and achieving increased price efficiency (2) livestock farmers to acquire know-how for producing quality Hanwoo beef, (3) the ongoing Government policy of enhancing price-quality competitiveness, and for improving the quality Hanwoo beef marketing to take root. (4) consumers to increase their ability to distinguish meat quality, and others.

• Journal of Preventive Medicine and Public Health
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• 제55권1호
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• pp.19-27
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• 2022

This study estimated the direct and indirect socioeconomic costs of 238 diseases and 22 injuries from a social perspective in Korea from 2007 to 2015. The socioeconomic cost of each disease group was calculated based on the Korean Standard Disease Classification System. Direct costs were estimated using health insurance claims data provided by the National Health Insurance Service. The numbers of outpatients and inpatients with the main diagnostic codes for each disease were selected as a proxy indicator for estimating patients' medical use behavior by disease. The economic burden of disease from 2007 to 2015 showed an approximately 20% increase in total costs. From 2007 to 2015, communicable diseases (including infectious, maternal, pediatric, and nutritional diseases) accounted for 8.9-12.2% of the socioeconomic burden, while non-infectious diseases accounted for 65.7-70.7% and injuries accounted for 19.1-22.8%. The top 5 diseases in terms of the socioeconomic burden were self-harm (which took the top spot for 8 years), followed by cirrhosis of the liver, liver cancer, ischemic heart disease, and upper respiratory infections in 2007. Since 2010, the economic burden of conditions such as low back pain, falls, and acute bronchitis has been included in this ranking. This study expanded the scope of calculating the burden of disease at the national level by calculating the burden of disease in Koreans by gender and disease. These findings can be used as indicators of health equality and as useful data for establishing community-centered (or customized) health promotion policies, projects, and national health policy goals.

• 가족자원경영과 정책
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• 제26권3호
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• pp.19-34
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• 2022

청년층 및 저소득층을 포함한 취약계층과 제2금융권을 중심으로 한 부채 불이행에 대한 우려가 증가하고 있다. 청년층의 가계부채 건전성은 최근 고용 부진, 학자금대출 부담 증가, 제2금융권에서 고금리 대출 증가 등이 복합적으로 작용하여 더욱 취약해졌다. 본 연구의 목적은 한국의 청년층 차입자를 대상으로 채무 불이행 가능성을 진단하고, 그 가능성에 영향을 주는 요인을 예측하는 것이다. 이러한 목적을 달성하기 위하여 본 연구는 2021년 「가계금융·복지조사」를 활용하고, 청년층의 채무 불이행 가능성과 관련된 요인들을 포괄적으로 분석하기 위하여 머신러닝 알고리즘의 랜덤포레스트 방법을 적용하였다. 청년층 차입자의 채무 불이행 위험을 예측하는 모형을 탐색한 뒤 중요도 지수를 산출하고, 중요도가 높은 설명변수들을 선별한 뒤, 주요 결정요인들의 부분 의존성 도표를 제시하고자 하였다. 최종적으로 자산대비부채비율(DTA), 의료비 비중, 가계부실위험지수(HDRI), 통신비 비중, 주거비 비중이 주요한 변인으로 나타났다.

• 한국지반신소재학회논문집
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• 제22권3호
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• pp.27-35
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• 2023

굴착 공사 중 가시설의 안정성을 확보하는 것은 매우 중요하다. 설계 시 지반의 안정성을 수치해석을 통해 분석하고 있지만, 시공시에는 여건이 달라지기 때문에 계측으로 벽체 안정성을 분석하는 일은 필수불가결한 일이다. 공사현장에서의 계측비용은 매우 낮은 단가로 책정되어있으며 이를 통해 흙막이 벽체의 사고위험성은 예측되고 있다. 따라서 본 연구에서는 흙막이 벽체의 자동 혹은 무선 시스템 계측의 중요성을 가상의 사고사례 분석을 통해 공사기간 및 사고비용을 산정하고 이를 계측비용과 비교하여 무선 및 자동계측 업무의 중요성을 주장하였다. 굴착공사 중 중대형 파괴 시 사고처리 금액에 대하여 계측비용은 5% 미만으로 계측비용을 증가시켜 사고를 미연에 방지하는 것이 경제적일 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2211-2216
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• 2007

Liquefied gas vaporizer means machine to vaporize the liquefied gas as liquid nitrogen($LN_2$), liquefied natural gas(LNG), liquid oxygen($LO_2$) etc. In the air type vaporizer, the frozen dew is also created by temperature drop (below 273 K) on vaporizer surface. This problem increases as the time progresses and humidity increases. In addition, the frozen dew gradually becomes frost deposit consequently, heat transfer through vaporizer decreases because frost deposit form adiabatic sheet. Because of this reason, recent vaporizer system is installed as parallel type, this vaporizer system needs more expensive installation costs and more space. This paper was investigated on the heat transfer characteristics of liquefied gas vaporizer with super low temperature and this paper was carried out the numerical about air heating vaporizer with super low temperature. The numerical analysis on the heat transfer was studied on the effect of geometric parameters of the vaporizer, which are length 1000 mm of 4fin75le type vaporizer. 4fin75le means number of fin is 4 and height of fin is 75 mm.

• 한국분말재료학회지
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• 제3권4호
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• pp.227-232
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• 1996

(i) The development of a metallurgical bond during the spray forming of clad products has offered the possibility of manufacturing large rolls, including those used in hot and cold strip mills. Small rolls are already being produced in Japan. (ii) Technical developments, including the use-of-multi-atomizers have resulted in the elimination of porosity from the internal bore of a sprayed tube. Bimetallic tubing can also be manufactured and the installation of a 4.5 ton tube plant in the USA should provide low operation costs. (iii) Spray forming offers a potentially low cost manufacturing route for superalloy ring/casing components in high strength superalloys. (iv) A large pilot plant has been built for the spray forming of ultra-clean superalloys for turbine disc applications. (v) Using twin-atomizing technology, special steel billets have been spray formed up to 400mm diameter with deposition yields in excess of 90%. (vi) Al/Si alloy extrusion billets with excellent dimensional tolerances are being manufactured for large scale automotive applications. Several new aluminum alloys have also been developed, including high strength, low density and low cocfficient of expansion materials. (vii) New copper alloys have been developed and pilot plants are in operation to produce these alloys once markets have become established.

• Journal of Advanced Marine Engineering and Technology
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• 제27권2호
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• pp.280-288
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• 2003

We need refrigeration system which can maintain the freshness of agricultural products, because of being distance from a tiller to a consumer. Vacuum Pre-cooling system has an advantage in quality maintenance through vapid cooling down by using latent heat of evaporation of stored products. A number or thawing methods in current use have also several disadvantages in thawing time. discoloration mass loss caused by drying, capital costs and running cost. These damages are, it is claimed, either eliminated or improved by the vacuum thawing system. An experimental study on the pre-cooling for the bean sprouts and cabbage, and thawing for hairtail and croaker by the low temperature vacuum system were carried out. The cabbage cooling time with this Pre-cooling vacuum system took about 60 minutes to reach from $23.2^{circ}C to 4.5^{\circ}C$ at 5 mmHg abs. ($6.66\times10^{-4}$ MPa). The croaker thawing time with this low temperature vacuum thawing system took about 170 minutes to reach from $-10.3^{circ}C to -0.8^{\circ}C$ at 20 mmHg abs ($2.67\tiems10^{-3}$MPa). The vacuum Pre-cooling and thawing system have merits compared with present systems in their short intervals to cool down and to thaw without any quality losses.

• 한국항만경제학회지
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• 제36권1호
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• pp.23-40
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• 2020

본 연구는 IMO 2020 시행에 따른 국내외 선사의 대응전략을 살펴보고, 선사의 주요 대응방안인 저유황유로 연료를 전환할 경우 국적선사가 부담해야 할 추가비용과 그것이 선사의 수익성에 미치는 영향을 시나리오별로 분석하였다. 분석결과, 저유황유 사용 시 국적선사는 상당한 추가 비용이 발생하게 되고 이로 인해 모든 시나리오에서 영업이익 적자를 기록하는 등 수익성이 악화될 것으로 분석되었다. 이러한 결과는 대화주 운임교섭력이 약한 근해선사의 경우 연료유 가격에 탄력적으로 적용할 수 있는 합리적인 BAF 설정 기준이 필요하며, 또한 정유사, 화주, 선사 간 상호협력을 통해 상생할 수 있는 방안을 모색할 필요가 있음을 시사한다.

• 대한간호학회지
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• 제34권1호
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• pp.191-201
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• 2004

Purpose: This study aimed to evaluate economic viability of public health center visiting nurse services for the low-income elderly with long-term care needs. Method: The sample consisted of 252 community dwelling elderly who enrolled in public health center visiting nurse services for three months or more. Data was collected on physical (ADL and IADL) and cognitive impairments of the elderly, contents and frequency of visiting nurse services, cost per visit, and costs of alternative services for long-term care. Result: The mean score of ADL and IADL levels of the elderly was 2.80.4904, which indicated these patients were mostly independent. Eighty four percent of the elderly subjects were cognitively intact. Among visiting nurse services supplied, providing assessment was 34%, followed by education and counseling 26%, medication 22%, and referral. The mean cost per visit was 17,824.1 won, which transformed into a total cost per person per year of 161,130.2 won. Comparing the cost of a visiting nurse service with those of other long-term care alternatives, the visiting nurse service was the least costly alternative, followed by an outpatient clinic, hospital based home care, and nursing home. Conclusion: Overall, the results of the study provide evidence of the economic viability of visiting nurse services for the low-income elderly among long-term care alternatives.