• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.1112-1117
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• 2005

Construction cost index is generally used to estimate the new project cost based on past construction data and to adjust contract cost when the price change of various articles and items of expenditure composing the contract occurs. In Korea, it is mostly used for adjustment of construction contract cost due to fluctuation of prices. However index adjustment rate which is used for adjustment of construction contract cost had some problems in calculating cost index of each expenditure item that could not reflect properly the change of construction cost. For supplementing these problems, the research of developing construction cost index has been executed. Through the precedent research, these problems were partially resolved but still remain. Therefore this research proposes method of making cost index that utilizes representative items of labor, material, and equipment by analyzing bill of quantity of road construction, through analysis and comparison of precedent study. By using this method, it is expected to solve problems which were not reflected in precedent studies.

• Journal of the Korean Data and Information Science Society
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• 제25권6호
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• pp.1361-1369
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• 2014

월세가격 동향을 살펴볼 수 있는 국가승인통계인 월세가격동향조사는 8개시도 (수도권 및 지방광역시)의 3,000개 월세표본에 대하여 매월 월세가격을 파악하여 지역별, 주택유형별, 규모별 월세가격지수 및 증감률, 그리고 월세이율을 공표하고 있다. 이 통계에서 제공되는 월세가격지수는 월세시장 동향을 파악하는데 매우 중요한 지표로서, 적절한 주택정책의 수립과 평가에 활용되고 있다. 월세가격지수는 보증금과 월세의 이원적인 가격자료를 전월세전환율을 이용하여 완전월세액이라는 하나의 가격자료로 환산하여 그 변화율을 측정함으로써 산정되는데, 적용되는 전월세전환율 종류에 따라 상이한 가격지수가 도출될 수 있다. 현재 적용되고 있는 전월세전환율 하에서는 임차인의 입장에서 월세부담이 상승했다 하다라도 전세금 수준이 더 많이 상승한 경우 전월세전환율이 낮아져서 결과적으로 월세가격지수가 하락하는 현상이 발생될 수 있다. 따라서 현행 월세가격지수의 변동률에 대한 해석에 유의할 필요가 있다. 본 논문에서는 월세가격지수의 변동률을 전월세전환율 변화에 기인한 부분과 그렇지 않은 부분을 구분하여 분석할 수 있는 틀을 제공하고자 한다. 이러한 방법을 통하여 현재와 같이 전세금이 급격하게 상승하는 시장에서 월세가격지수가 떨어지는 경우, 적용된 전월세전환율 효과에 기인하지 않는 실제 월세수준의 변동 흐름을 보다 정확하게 파악할 수 있다.

• 한국군사과학기술학회지
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• 제23권3호
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• pp.237-245
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• 2020

In this paper, I introduce Phase-Change Cooling for thermal management of high power devices that can be applied to High Power Laser and Electric Propulsion Systems which are composed of multiple distributed superheat sources. Phase-Change Cooling can be good used to efficient cooling of their heat sources. Phase-Change Cooling has extremely high efficiency of two-phase heat transport by utilizing heat of vaporization, relatively low flow rates and reduced pumps power. And I suggest TPI(Thermal Performance Index) which is a quantitative performance index of Phase-Change Cooling for thermal management. I quantify the performance of Phase-Change Cooling by introducing TPI. I present the test results of TPI's changing refrigerant, heat sink and flow rate of the Phase-Change Cooling system through the experiments and analyze these results.

• 산경연구논집
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• 제11권8호
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• pp.31-38
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• 2020

Purpose: This study uses 'Autoregressive Integrated Moving Average Model' to predict the impact of a sharp drop in the base rate due to COVID-19 at the present time when government policies for stabilizing house prices are in progress. The purpose of this study is to predict implications for the direction of the government's house policy by predicting changes in house transaction prices and house rental prices after a sharp cut in the base rate. Research design, data, and methodology: The ARIMA intervention model can build a model without additional information with just one time series. Therefore, it is a time-series analysis method frequently used for short-term prediction. After the subprime mortgage, which had shocked since the global financial crisis in April 2007, the bank's interest rate in 2020 is set at a time point close to zero at 0.75%. After that, the model was estimated using the interest rate fluctuations for the Bank of Korea base interest rate, the house transaction price index, and the house rental price index as event variables. Results: In predicting the change in house transaction price due to interest rate intervention, the house transaction price index due to the fall in interest rates was predicted to change after 3 months. As a result, it was 102.47 in April 2020, 102.87 in May 2020, and 103.21 in June 2020. It was expected to rise in the short term. In forecasting the change in house rental price due to interest rate intervention, the house rental price index due to the drop in interest rate was predicted to change after 3 months. As a result, it was 97.76 in April 2020, 97.85 in May 2020, and 97.97 in June 2020. It was expected to rise in the short term. Conclusions: If low interest rates continue to stimulate the contracted economy caused by COVID-19, it seems that there is ample room for house transaction and rental prices to rise amid low growth. Therefore, In order to stabilize the house price due to the low interest rate situation, it is considered that additional measures are needed to suppress speculative demand.

• 자원ㆍ환경경제연구
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• 제9권3호
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• pp.489-513
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• 2000

This paper introduces a new method to estimate and decompose sources of carbon dioxide emissions using an input-output model with decomposition method free of residual usually associated with this kind of analysis. This method is different from others, using what we call 'mean rate-of-change index (MRCI)' for weights of the decomposed terms. Ang et al.(1998) asserted that logarithmic mean divisia index(LMDI) is superior to Laspeyres index(LI) or simple average divisia index(SADI) since it reduces residual to zero. We claim that our method is an improvement over the other methods because it enables residual free decomposition even when data contain negative values, the case which LMDI cannot handle. We demonstrate by way of showing some examples that our method is superior to LI, SADI(Proops, 1993 and Chung, 1998) or LMDI(Ang et al., 1998).

• 전기학회논문지
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• 제58권11호
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• pp.2122-2127
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• 2009

This study presents the failure rate and repair rate of Superconducting Fault Current Limiter(SFCL) and adjacent distribution equipments. When the fault current penetrated SFCL, the supply of electric power to the customers can be partly continued. It is expected that SFCL makes to improve the reliability index of customers. Contrary to the expectations, the series connection between SFCL and distribution system could deteriorate the reliability index. To evaluate the reliability index in the distribution system including SFCL, the failure rate and repair rate of SFCL are required as well as that of distribution equipments. Also, the insertion of SFCL makes to change the failure rate and repair rate of adjacent equipments. This study proposes a method to calculate the failure rate and repair rate of a component combining SFCL and adjacent equipments.

• 한국자원식물학회지
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• 제33권2호
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• pp.106-115
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• 2020

본 연구는 봄 식물계절지수와 기온지표와의 관계를 알아보기 위해 지난 9년간(2010년-2018년) 대구수목원, 팔공산, 주왕산, 가야산에 공통적으로 생육하는 소나무, 일본잎갈나무, 신갈나무, 진달래, 생강나무, 당단풍나무 6종을 대상으로 발아, 개화, 개엽의 봄 식물계절 시기의 변화 경향과 기온간의 관계를 파악하였다. 기온의 변화는 9년동안2월 보다 3~4월의 월평균 기온이 증가하였으며, 지역별로 수목원과 팔공산의 평균기온이 높았다. 발아, 개화, 개엽은 수종별로 생강나무가 가장 빠르며 소나무가 가장 느렸고, 지역별로 수목원에서 가장 빨리 식물계절시기가 도래하였다. 봄 식물계절시기는 -1.267~-6.151일/9년 정도 앞당겨지고 있는 경향을 보이는데 소나무(-6.151일/9년)가 가장 크며, 진달래(-1.267일/9년)의 변화율이 가장 낮았다. 발아, 개화, 개엽에서 모두 유의한 값을 보이는 수종은 진달래와 소나무로서 이들은 1월~3월 평균기온과 상관관계를 보였다. 봄 식물계절지수(SPI)의 시계열 변화를 확인한 결과 4개 지역의 변화율이 모두 음의 값으로 식물계절 시기가 모두 빨라지고 있었다. 그 중 수목원, 팔공산 및 가야산과 같은 내륙지역일수록 변화율이 컸으며, 다소 거리가 떨어진 주왕산의 경우 변화율이 조금 낮게 나타났다.

• 한국태양에너지학회 논문집
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• 제27권4호
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• pp.67-75
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• 2007

This study intends to the adequacy inspection of the room temperature variation rate that is available in the building heat performance evaluation index, so we performed the sensitivity analysis about the room temperature variation rate and the energy consumption in the room. For these purpose, we supposed the models which are composed of the various window area, insulation thickness and ventilation rate. Then we analyzed the simulation using the ESP-r and Seoul weather data. In this research, the pattern of the increasing & decreasing rate of annual load according to the change of the various design factors is similar to the pattern of increasing & decreasing rate of not the K-values but the room temperature variation rate. Also we derive the optimum value of the various design factors and the room temperature variation rate in this analysis model. Further study is to be required the development of convenient tool to use in the real design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.975-978
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• 1997

This Paper presents a high impedance fault (HIF) detection algorithm of distribution systems using wavelet transform. Two HIFs on dry soil and sandy soil were simulated on various load conditions in 22.9 kV distribution systems using EMTP, and the current wavelets were decomposed by wavelet transform. The current root mean square(rms) change, the index change rate and the relative amplitude change were used as the multi-criteria for a HIF detection. The index change rate and the relative amplitude were made using the wavelet coefficients.

• 한국건설관리학회논문집
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• 제5권6호
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• pp.203-211
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• 2004

본 연구는 전문가를 대상으로 한 델파이(Delphi) 설문조사를 통하여 물가 변동에 따른 건설공사 계약 금액 조정(escalation) 제도의 문제점 및 개선 방안에 대하여 살펴본 결과이다. 조사 결과, 에스컬레이션의 요건이 되는 건설공사비의 등락률은 소비자 물가 변동률 혹은 건설 공사비 지수에 근거하여 결정하는 것이 바람직하며, 전문가의 의견을 보면, 총 공사금액의 $3\%$ 수준이 적정한 것으로 나타났다. 나아가 환율 및 국제 원자재 가격 등 단기적 충격 요인에 기인하는 자재 가격의 급등은 건설업체가 사전적으로 예측하여 대응하는 것이 어렵다. 따라서 단품슬라이드 제를 도입하여 특정 자재의 가격 급등에 대하여 에스컬레이션을 허용할 필요성이 있다. 등락률의 산정 방식으로는 지수조정률보다는 개별 공사의 특성을 정확하게 반영할 수 있는 품목조정률이 더 바람직한 것으로 평가되었다. 지수조정률이 합리적으로 기능하기 위하여는 품목별 공종별로 노임지수와 자재지수, 기계경비지수 등이 산출되어 발표될 필요성이 있다. 에스컬레이션의 기산일로서는 현행 법령에서는 계약 체결일로 규정되어 있으나, 계약 체결 이전부터 물가 변동이 발생한다는 점을 고려할 때, 입찰일로 규정하는것이 바람직하다.