• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.449-456
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• 2010

The HCCI engine is a prospective internal combustion engine with which high diesel-like efficiencies and very low NOx and particulate emissions can be achieved. However, several technical issues must be resolved before HCCI engines can be used for different applications. One of the issues concerning the HCCI engine is that the operating range of this engine is limited by the rapid pressure rise caused by the release of excessive heat. This heat release is because of the self-accelerated combustion reaction occurring in the engine and the resulting engine knock in the high-load region. The purpose of this study is to evaluate the role of thermal stratification and fuel stratification in reducing the pressure rise rate in an HCCI engine. The concentrations of NOx and CO in the exhaust gas are also evaluated to confirm combustion completeness and NOx emission. The computation is carried out with the help of a multizone code, by using the information on the detailed chemical kinetics and the effect of thermal and fuel stratification on the onset of ignition and rate of combustion. The engine is fueled with dimethyl ether (DME), which allows heat release to occur in two stages, as opposed to methane, which allows for heat release in a single stage.

• 월간 기계설비
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• s.21
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• pp.69-73
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• 1992

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.244-250
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• 1999

This study aimed to analyze the effect of the change in CP class of a firm on the abnormal yield of its stock price. As a result, it was found that the change in CP class of a firm had an effect on the abnormal yield. That is. the abnormal yield rose when the class of CP rose while it dropped when the class of CP dropped. And it was analyzed that the class of CP in the firm in which its current net gain was great while it dropped in the firm in which the current net gain was small. And it was found that the CP class of the firm with the high debt to equity ratio rose when the CP class of the firm changed, whereas it rose in the firm with the low debt to equity ratio. But it was found that the size of majority shareholders equity rate in a firm, the size of corporate value of the firm, the size of cash flow of the firm and the size of the burden of financial costs of the firm were not related to the abnormal yield of its stock price. This study has its significance in analyzing the effect of the information on the change in CP class of the firm on the capital market. But it has its limitations in the sample firm and the selection of the point in time of disclosure.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.104-107
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• 1995

지구온난화에 따른 해면상승이 일어난다면 한국 서해안과 같은 완경사의 간사지의 범람은 크게 일어날 것이다. 향후 2010년 까지의 해면상승에 대한 정량적인 예측에는 불확실성이 있으나 적어도 과거 1세기의 해면상승률 보다는 최소 2배이상일 것으로 추정되고 있다. 또한 IPCC(Inter-governmental Panel on Climate Change)는 각국이 100cm의 go면상승에 대한 영향평가를 수행할 것을 권장하였는데 미국 EPA는 이 보다도 더 비관적인 상승을 추정하고 있다. (중략)

• The Korean Journal of Financial Studies
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• v.5 no.1
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• pp.19-47
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• 1999

본 연구는 기업가치 추정모형인 EVA모형과 FCFF모형의 적합성을 한국주식시장을 대상으로 검증하는데 목적을 두고 있다. 1992년$\sim$1996년의 5년간 상장기업을 대상으로 분석한 결과는 다음과 같다. 실제주가와 이론주가간에 음(-)의 괴리율을 갖는 집단의 누적평균초과수익률은 EVA 모형 기준인 경우 40일$\sim$60일간에 유의적으로 상승하고 있으며, FCFF모형의 경우 1일$\sim$20일간에 유의적으로 상승하고 있다. 그리고 실제주가와 이론주가간에 양(+)의 괴리율을 갖는 집단의 누적평균초과수익률은 EVA모형 기준인 경우 21일$\sim$40일간에 유의적으로 하락하고 있으며, FCFF모형 기준인 경우 1일$\sim$20일간에 유의적으로 하락하고 있다. 또한 EVA모형과 FCFF모형 모두에서 음(-)의 괴리율집단과 양(+)의 괴리율집단간의 누적평균초과수익률은 기준일 이후 유의적 차이를 보이고 있다. EVA모형과 FCFF모형으로 평가한 결과는 반영시점이 다소 차이가 난다는 점을 제외하고는 상대적으로 과소평가된 주식은 기준일 이후 가격이 상승하고 상대적으로 과대 평가된 주식은 기준일 이후 하락한다는 사실을 보여주고 있다. 이런 사실은 제한적이지만 절대가치평가모형이 한국주식시장에서 어느 정도 적합성을 가질 수 있는 가능성을 보여주고 있다.

• International Area Studies Review
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• v.12 no.3
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• pp.49-67
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• 2008

In this paper, we address the problem of optimal monetary policy rule in the presence of abrupt shifts in the structure of the economy. To do so, we first estimate a Markov switching model for the US housing price inflation, and find evidence supporting the presence of two distinct regimes for the US housing price inflation. One of the two regimes identified appears 'usual', in that housing price inflation negatively responds to higher real interest rate. The other regime is 'unusual', in that the housing price inflation is positively related with real interest rate. We then solve an optimal control problem of the FRB under the presence of the two regimes thus identified. The optimal policy is 'asymmetric' in that the optimal responses in the 'usual' regime require the FRB to lean against the wind to inflationary pressure, while the FRB is recommended to accommodate it in the unusual regime. It is also found that the optimal degree of responses is more conservative when the FRB acknowledges the uncertainty about future regime.

• Journal of Cadastre & Land InformatiX
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• v.48 no.2
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• pp.5-20
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• 2018

This paper aims to analyze characteristic by the cities focused on the ratio of new apartment resale that is one of the apartment unit sale market, which has been increased recently. So, this study examined characteristics of population, apartment trade & sale, housing with 162 cities and counties and performed multiple regression analysis with dependent variable, ratio of new apartment resale. As a result. the factors affecting the ratio of new apartment resale are 7variables, apartment sales rate, transfer of ownership, apartment turnover rate, sale volume, regional apartment rate, population increasing rate, housing average apartment sale price rate. In terms of the increase in apartment sales prices, the rate of sales price increase was relatively low in areas where the transaction rate for apartment sales is high, and the number of apartment sales right transactions increased as the number of other ownership transfers rose. As a result, the data will be based on the improvement of the government's policies and systems to stimulate the transaction focused on the real estate agents in the apartment market.

• The Korean Journal of Financial Management
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• v.22 no.2
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• pp.107-133
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• 2005

The object of this study is to examine the informational effect of the rating change announcement on the capital market. For this study, daily stock prices from January 1993 to February 2001 and daily bond prices from July 2000 to February 2001, for the bond market are used. In the stock market, we could not observe any statistically significant stock price reaction to rate change announcements from July 2000 to February 2001. However, if rating agencies announce more than two degradation for the period of January 1993 to February 2001, statistically negative significant stock price reactions are observed. On the other hand, there is no statistically significant stock price reaction to any other rating change announcement. In the bond market, there is no statistically test on the bond price reaction, but the general directions of bond price movements are consistent with the effect we can expect from rating change announcements. Generally, when the rating agencies degraded more than two grades at once, a cumulative abnormal returns move negatively during the overall period. In this case, we can say that rating agencies' role is to confirm information or investor's expectations. However, for the other cases, we could not observe my significant movement before or on the event data.

• Proceedings of the Safety Management and Science Conference
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• 2008.11a
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• pp.441-455
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• 2008

본 논문은 단기 및 장기간에 걸쳐 부동산시장의 동태적 자금흐름과 수익률 분석에 초점을 맞추고 있다. 본 논문에서는 부동산시장의 실증적 동태적 자금흐름과 수익률 분석은 VAR모형을 사용하였으며 다양한 금융 및 경제관련 변수들을 연구에 포함시키고 있다. 실증적 분석 결과에 따르면 우리나라에서도 기존의 미국 연구 사례에서와 같이 금융시장의 자금흐름을 통하여 부동산시장의 동태적 자금흐름을 예측할 수 없다는 점을 파악할 수 있다. 또한 Granger 인과성 검정 결과에 따르면 통화정책 및 증권시장 변수 모두 전국아파트 매매가격, 전국 단독주택 매매가격, 전국 전세아파트 매매가격 실질상승률 등의 부동산관련 변수에 통계적으로 유의한 영향이 크지 않음을 알 수 있다. 그러나 분산분해 결과에 따르면 전국아파트 및 전국전세아파트 매매가격 실질상승률에 대한 움직임에 코스피수익률의 영향력이 증대될 수 있음을 알 수 있다.

• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.21-28
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• 2009

The purpose of this study is to gain a better understanding of the effects of thermal stratification and partial fuel stratification on reducing the pressure-rise rate and emission in HCCI combustion. The engine is fueled with Di-Methyl Ether(DME) which has unique 2-stage heat release. Computational work is conducted with multi-zones model and detailed chemical reaction scheme. Calculation result shows that wider thermal stratification and partial fuel stratification prolong combustion duration and reduce pressure rise rate. But too wide partial fuel stratification increases CO and NOx concentration in exhaust gas, and decreases combustion efficiency.