• 오토저널
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• 제15권2호
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• pp.44-52
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• 1993

In this study, the characteristics of decreasing exhaust gas of diesel engine was examined in dual fuel method by using commertial LPG for automotive. LPG was supplied to engine intake port by fumigation method and flow rate was controlled by using the needle valve. LPG supply ratios were 0, 20, 30% of total fuel amount to be supplied to engine by mass base. We investigated the effect of LPG supply ratio on exhaust gas concentrations related to excess air ratio and engine load at 1600, 1800, 2000 rpm. Soot concentration decreased about 30% in proportion to the increase of the LPG supply ratio. NOx concentration decreased in proportion to the increase of the LPG than diesel only and the increase rate was higher at low engine load. BSFC(Brake specific fuel consumption) was lower in proportion to the increase of the LPG supply ratio at high engine load and to the decrease of LPG supply ratio at low engine load.

• 한국환경과학회지
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• 제14권6호
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• pp.533-542
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• 2005

In this study, an optimization technique was developed from the application of Allocation Rule. Average Allocation coefficients of the Andong and Imha dam compare constant water supply condition with vary water supply condition that are above the contribute ratio $67\%\~50\%$ the Andong dam in Rule(A)-Rule(C). In the Refill Season, Andong dam water supply contribution is higher than Imha dam at the Control point water supply. In the Allocation analysis results, Rule(A) is calculated storage ratio because Andong dam contribute to Control point larger than Imha dam which Andong dam storage is larger than Imha dam storage. Rule(B) calculated sum of the storage and inflow ratio for Andong dam and Imha dam, as Andong dam contribution is higher than Imha dam. Rule(C) calculated that sum of storage, inflow and water supply is divided average storage ratio, as the best results of the Allocation coefficients and water supply capacity. The results of storage analysis is larger vary water supply condition than constant water supply condition and the results of water supply analysis is larger vary water supply condition than constant water supply condition. Water supply deficit is decrease $30\%$ for vary water supply condition.

• 한국태양에너지학회 논문집
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• 제33권2호
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• pp.42-49
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• 2013

Recently, the attention to renewable energy has increased globally because of the environmental issue and the global energy crisis. Accordingly, south korea is focused on increasing the renewable energy usage. And the government enforced a law to the public buildings to install the renewable energy facilities. In this study, the building to evaluate renewable energy consumption and supply ratio was selected. This building has 9.79% of renewable energy supply ratio by PV system. In this study, the method for improving renewable energy supply ratio was analyzed using additional PV system. And The 5 methods to increasing electricity were evaluated. The method of increase 4.24 times PV arrays area is most efficient way to increase the renewable supply ratio. The case 1, show that the increasing renewable energy supply ratio of 39.2% compared to exsiting PV system. The result of the above, consider the additional supply of renewable energy.

• 한국물환경학회지
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• 제28권2호
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• pp.202-212
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• 2012

Due to the deterioration of water supply network and the deficiency of raw water, the water utility of local governments have performed various projects to improve their revenue water ratio. However, it is very difficult to estimate the cost for maintaining the revenue water ratio at higher level after completing the project, because local governments have different conditions affecting the operating and maintenance cost of water supply network. The purpose of this study is to present a procedure to estimate the operating and maintenance cost required to maintain the target revenue water ratio of the water supply network. For this purpose, we estimated the cost used only for operation and maintenance of water supply network of 164 local governments with the aid of K-Mean Clustering Analysis and the data from 40 representative local governments. Then, the regression analysis was performed to find relationship between revenue water ratio and the operating and maintenance cost with two different data sets generated by two classification methods; the first method classifies the local governments by means of k-means clustering, and the other classifies the local governments according to the index standardized by the operating and maintenance cost per unit length of water mains per revenue water ratio. The results shows that the method based on the index standardized by the cost and revenue water ratio of each government produces more reliable results for finding regression equations between revenue water ratio and the operating and maintenance cost only for water supply network. The estimated regression equations for each group can be used to estimate the cost required to keep the target revenue water ratio of the local government.

• 한국건설관리학회논문집
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• 제6권2호
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• pp.61-68
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• 2005

지역별 적정 주택량을 공급하기 위해 수요예측 모형을 구축한다 예측모형은 자료유형에 따라 다소 차이가 있으나 시계열자료(Time Series Data) 분석기법에 의한 모형 구축 시 추정대상 지역특성을 민감히 반영할 수 있는 영향인자가 필요하다. 도시지역을 인구규모로 분류하여 영향인자를 분석할 경우, 대도시와는 달리 중 $\cdot$ 소도시는 주택량과 상수도보급률의 변화가 일정기간 민감한 상관관계가 존재하는 것으로 조사되고 있다. 이에 따라 중 $\cdot$ 소도시 주택수요 예측을 위해 상수도보급률을 유용하게 적용할 수 있는 구간, 즉 예측모형 구축이 가능한 시점까지의 도시 주택량과 인구수 규모를 찾아낼 필요가 있다. 따라서, 전국 중 $\cdot$ 소도시를 대상으로 주택량과 상수도 보급률의 상관관계가 중 소도시 지역에서만 있는 것으로 조사된 기존 연구 결과를 재 입증하고, 지역별 상관관계가 완화되는 시점의 시기, 상수도보급률, 주택량, 인구수 규모를 발견하는 것을 본 연구의 목적으로 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.857-861
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• 1997

In discontinuous wheel grinding, temperature is different form conventional grinding. The characteristics of discontinuous grinding with respect to various slotted wheel were compared with those of general grinding. Thermal conditions vary with intermittent ratio, direction of fluid supply for discontinous wheel. According to three direction of grinding fluid supply and intermittent ratio,temperature and surface roughness were analyzed.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2011년도 춘계학술발표대회 논문집
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• pp.187-192
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• 2011

The purpose of this study is to evaluate the supply plan of public rental housing under the Lee Myung-bak government. According to the supply plan, the government will supply public rental housings by 80,000 unit every year from 2009 to 2018, and achieve 12% as stock ratio in 2018. To evaluate the supply plan, this study analyzed housing needs of tenants in private rental housing by using the raw data of Korea Welfare Panel Survey(2008). The results are as follows: (1) It is difficult for the supply plan to meet the housing needs of tenants in private rental housing. (2) The link between supply plan and stock ratio target is weak. (3) To meet the housing needs, it is necessary to supply public rental housings by 107,000 unit every year for 10 years, and, in this case, the stock ratio will be 10% in 2018. In conclusion, this study proposed that the supply plan of public rental housing should be redesigned.

• 한국주거학회논문집
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• 제23권1호
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• pp.1-8
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• 2012

The purpose of this study is to evaluate the supply plan of public rental housing under the Lee Myung-bak government. According to the supply plan, the government will supply public rental housings by 80,000 unit every year from 2009 to 2018, and achieve 12% as stock ratio in 2018. To evaluate the supply plan, this study analyzed housing needs of tenants in private rental housing by using the raw data of Korea Welfare Panel Survey (2008). The results are as follows: (1) It is difficult for the supply plan to meet the housing needs of tenants in private rental housing. (2) The link between supply plan and stock ratio target is weak. (3) To meet the housing needs, it is necessary to supply public rental housings by 107,000 unit every year for 10 years, and, in this case, the stock ratio will be 10% in 2018. In conclusion, this study proposed that the supply plan of public rental housing should be redesigned.

• 유통과학연구
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• 제20권6호
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• pp.125-135
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• 2022

Purpose: The revenue sharing contract has been used in various industries and it is expected to coordinate the individual companies' operations in a way to improve the whole supply chain performance. This study evaluates the performance of the revenue sharing contract to find out whether this contract achieves its original goal, the supply chain coordination. Research design, data, and methodology: The profit optimization models are developed to represent two stage supply chain system with a supplier and a buyer. By using the numerical examples of the proposed mathematical models, this study examines whether this supply chain contract coordinates the supply chain system. Results: The numerical examples show that the revenue sharing contract does not make the same supply chain profit as the centralized system does. With the proper combination of the wholesale price discount rate and revenue share ratio, both manufacturer and retailer can obtain increased profits from the revenue sharing contract. Conclusions: The outcomes of the numerical analysis imply that the revenue sharing certainly improves the supply chain performance but it does not fully coordinate the supply chain system. By controlling the wholesale price and revenue share ratio, every supply chain member can be beneficiaries of this supply chain contract.

• 한국관개배수논문집
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• 제18권1호
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• pp.68-80
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• 2011

To provide a operation rule curve for reservoir with low ratio of watershed area to paddy field area, Duckyong reservoir with watershed area of $15.8km^2$ and paddy field area of 1,071ha was selected, in which 4 meters are being heightened and full water levels will be increased from EL.26.0m to EL.30.0m, total water storages from 365.6M $m^3$ to 708.0M $m^3$. There was no operation rule curve that satisfied over 90% reliability of water supply in reservoir with watershed area of 1.48 times of paddy field area. The differences between observed and simulated reservoir daily water storages were minimized to determine parameters for simulating reservoir inflow in case of paddy field area of 550ha from 1991 to 2010. A operation rule curve was drawn to have a maximum storage with total water storage, which was in paddy field area of 700ha with ratio of 2.3 between watershed area and paddy field area. This case showed that annual irrigation water supply was 668M $m^3$ and instream flow of 57M $m^3$, water supply reliability of 55.6% in normal operation, and annual irrigation water supply was 605M $m^3$ and instream flow of 38M $m^3$, water supply reliability of 95.6% in withdrawal limited operation. Water supply reliabilities showed 35.6% without flood regulation and 17.8% with flood regulation in existing reservoir before heightening.