• 한국양식학회지
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• 제16권4호
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• pp.203-209
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• 2003

Nitrification efficiency of fixed film biofilters with sand, loess bead, and styrofoam bead in biofilter columns of 1-m height and 30 cm width was studied. Synthetic wastewater was continuously supplied to the culture tank to maintain total ammonia nitrogen (TAN) concentration in the inflow water at around 8 mg/L. The hydraulic loading rate was set at 200 ㎥/$m^2$/day. TAN conversion was stabilized after about 90 day conditioning for all the selected filter media but with net accumulations of nitrite. On the volumetric basis, conversion rates of TAN and nitrite were the highest in styrofoam bead filter. Mean volumetric TAN conversion rates in the final samples were 682, 269, and 79 g TAN/㎥/day in the styrofoam bead, sand and loess bead filters, respectively. Low gravity and cost of styrofoam bead render the handling easier and more cost-effective.

• 한국콘텐츠학회논문지
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• 제20권3호
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• pp.245-253
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• 2020

전월세 전환율이 시장이자율 또는 임대인의 기대수익률이라면 전국의 전월세 전환율은 동일하여야 한다. 그러나 전월세 전환율은 항상 시장이자율보다 높은 수준을 유지하고 있다. 본 연구는 임대주택의 공급원가 구성요소를 현재의 주택가격, 시장이자율, 감가상각비, 보유세, 그리고 임대차에 따른 위험이 존재할 경우 위험프리미엄으로 파악하고 현재의 주택가격과 각 요소와의 관계를 파악함으로써 주택임차료를 현재 가격으로 표현하였다. 이를 통해 주택가격의 변동 폭을 암묵적으로 가정하거나 전월세 전환율에 현재의 주택가격이 반영되지 못한 단점을 극복하였다. 본 연구는 임대주택의 공급 원가를 구성 요소 간의 조합으로 표현함으로써 전월세 전환율이 시장이자율이 아니라 임대인의 필수수익률 또는 요구수익률임을 밝혔다. 이는 전월세 전환율이 항상 시장이자율보다 높은 현상도 설명할 수 있을 뿐만 아니라 전월세 전환율의 지역별 차이 및 주택 유형별 차이가 발생하는 원인도 설명할 수 있다.

• 지역연구
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• 제11권1호
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• pp.61-78
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• 1995

This study begins with a question of what spatial impact international trade policy would have following the Uruguay Round, particularly focusing on agricultural trade liberalization in Korea. Based upon the neoclassical urban economic model, it first identifies the channel in which agricultural market opening can ultimately affect both rural and urban are as; $\circled1$ Free trade will depress domestic price of agricultural products, $\circled2$ which will in turn depreciate agricultural land price. $\circled3$ The decrease in marginal supply cost for urban land will then facilitate urban sprawl, provided that the government relaxes restrictions on urban-rural land conversion. Theoretical analysis is further refined by empirical considerations that distinguish agricultural land value solely for production purpose from that for future urban, uses, and that distinguish the urbanization effect caused by the fall in the supply cost of urban land from that caused by the existing high level of demand. Utilizing the estimate of bid-price for paddy field derived from the revenue-cost relationship of rice production, simulation results show that the urban-rural boundary under trade liberalization can expand outward up to 70-85km radius in the Seoul metropolitan area, suggesting the emergency of a metropolis or even a megalopolis which extends from Seoul to the central part of the country. Since the geographic extent of urbanization effect can vary depending upon the urban spatial structure, however, it is recommended that the redevelopment option in the built - up area should always be tied up with the issue of whether to deregulate rural-to-urban land conversion.

• 한국산업정보학회논문지
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• 제26권6호
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• pp.35-46
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• 2021

본 연구는 4차 산업혁명시대와 Covid 19로 인해 비대면 라이프스타일이 가속화됨에 따라 배달 앱을 이용하는 사용자의 행태를 분석하였다. 구체적으로 본 연구는 배달 앱 서비스를 이용하는 고객의 지각된 서비스 품질이 전환비용, 고객 만족과 지속적 사용의도에 미치는 영향을 살펴보고, 그 결과를 토대로 배달 앱을 이용하는 이용자(고객), 배달 앱에 가입하여 운영하는 입점자(음식점), 그리고 고객과 음식점을 연결하여 주는 플랫폼(배달의 민족 등)에 유용한 정보와 시사점을 제공하는 것이 주요 목적이다.

• 산업경영시스템학회지
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• 제18권33호
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• pp.161-171
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• 1995

When physical distribution cost can be correctly measured, its management can also be efficient. Thus the primary objective of the study is to develop systems for measuring correctly physical distribution cost. The systems have two aspects : the One is the consumption of the resourses(materials, labor service, the other services), the other is the creation of physical distribution services(transportation, storage, cargo, packing, distribution conversion, management). By measuring the cost through the systems, the commoditization of the physical distribution services is possible and measurement of the cost and revenue can also be reasonable ,which makes its management efficient.

• International Journal of Industrial Entomology and Biomaterials
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• 제11권1호
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• pp.1-12
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• 2005

Feed conversion efficiency contributes directly or indirectly on the cost benefit ratio of silkworm rearing and is considered to be an important physiological criterion for evaluating the superiority of silkworm breeds/hybrids. Food intake, assimilation and conversion of indigenous as well as exotic silkworm races are well studied by many researchers. In this review, an attempt has been made to consolidate works on feed conversion aspects of indigenous and exotic silkworm races. The paper also deals with the effect of various factors viz., nutritional, environmental and feeding on food assimilation and conversion parameters of mulberry silkworm.

• 보건행정학회지
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• 제23권4호
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• pp.343-348
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• 2013

Background: Price control alone may not successfully restrain growth in health expenditures. This study aimed to propose fee adjustment model suitable for Korea reflecting health service volume and to clarify applicability of the model by comparing actual conversion factor with estimated conversion factor from simulation of this model. Methods: Fee adjustment model was developed based on Alberta's fee adjustment formula in Canada and 7 alternatives were assessed according to diversely applied parameters of the model. Results: Estimated conversion factors of the tertiary care hospital and the hospital were lower than actual conversion factors, since the utilization of heath service has been increased. However, there was no big difference between estimated conversion factors and actual conversion factors of the general hospital and the clinic. Eventually this fee adjustment model could estimate proper conversion factor reflecting health service volume. Conclusion: This model may be applicable to the mechanism as determining conversion factor between insurer and provider via negotiation and controling growth in health expenditures.

• Journal of Power Electronics
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• 제12권3호
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• pp.387-398
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• 2012

It is known that transformer based power supplies for ozone generators have low efficiency, high cost and exhibits a limited frequency range of operation. To overcome these disadvantages, this paper proposes a high frequency ozone generator with the absence of a transformer. The voltage step-up is achieved only by utilizing the resonant tank. This is made possible by a novel combination of ozone chamber materials that allow ozone to be generated at only 1.5 - 3.5 $kV_{p-p}$. The input to the resonant tank is driven by a PWM full bridge resonant inverter. Furthermore, zero-current zero-voltage switching (ZCZVS) operation is achieved by employing a duty factor of 25% between the switches of the full bridge. The advantages of the proposed system include high efficiency, low cost and the ability to control ozone production by varying the input voltage to the inverter. The prototype is verified by both simulation and experimental results.

• 대한예방한의학회지
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• 제12권3호
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• pp.21-34
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• 2008

Objectives : This paper analysed the alternative methods of calculating conversion factor for oriental medicine in the National Health Insurance and estimated the conversion factor(reimbursing price level) of the oriental medical services, based on health insurance claims data and macro economic data. Methods : Comparing cost accounting method, SGR model, and index model to estimate conversion factor in the national health insurance, six empirical models were derived depending on the scope of revenue considered in financial indicators. Classifications of data and sources used in the analysis were identified as officially released by the government. Results and Conclusion : Cost accounting analysis and SGR model showed a two digit decrease in the physician fee schedule of oriental medical services in the national health insurance, while index model indicated a positive increase in the fee reimbursed. As expected, SGR model measured an overall trend of health expenditures rather than an individual financial status of medical institutions, and index model properly estimated the level of payments to oriental medical doctors. Upon a declining share of health expenditures on oriental medicine, a global budget system fixed to a flat rate of total budget could be an opportunity as well as a challenge.

• Journal of Power Electronics
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• 제15권3호
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• pp.695-701
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• 2015

Uninterruptible Power Supplies (UPSs) can be largely divided into the passive-standby, line-interactive and double-conversion methods. This paper proposes a double-conversion UPS with a low cost and high performance. This single phase UPS uses a single-loop robust voltage controller and 1-switch voltage doubler strategy PFC. The proposed UPS is composed of a single phase PFC, a half-bridge inverter, a battery charger and a battery discharger. Finally, the validity of proposed UPS was verified by various experimental tests.