• Environmental and Resource Economics Review
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• v.8 no.1
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• pp.131-147
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• 1998

본 논문은 시차종속변수를 이용한 우리 나라 원목수요분석을 통해 장기원목수요의 변화를 예측하는 데 그 목적이 있다. 원목수요는 재화의 특성상 파생수요를 전제하여 분석하였다. 분석에서는 1970년부터 1996년까지 27년간의 원목수요 자료를 이용하였다. 원목수요는 1980년대 들어서면서 1970년대와 같은 빠른 증가는 아니지만 지속적으로 완만히 증가하다가 1991년을 정점으로 하향 안정세를 보이고 있다. 분석에서는 적응적 기대모형과 부분적 조정모형을 사용하였다. 1977년에서 1979년까지 원목수요량의 급격한 증가를 설명하기 위하여 모형내에 더미변수를 사용하였다. 설명변수는 원목가격, 더미변수, 파생재화(목재 및 나무제품)의 가격과 시차종속변수를 이용하였다. 분석 결과, 적응적 기대모형은 시차종속변수를 사용해야 할 만큼 유의한 결과를 얻을 수 없었다. 하지만 부분적 조정모형에서는 각 변수의 추정치가 전반적으로 유의하게 나타났다. 특히, 시차종속변수 추정치에 대한 t값이 2.07로 유의하게 나옴으로써 모형의 설명력을 높여 주었다. 부분적 조정모형의 수정계수는 0.74 정도로 나타났다. 부분적 조정모형의 가정하에 2010년까지 매년 원목가격지수 6.7%와 국내 목제품가격지수 5.8% 상승률에 근거한 방법과 원목가격지수 6.8%와 목제품가격지수 5.6%로 전제하여 원목수요를 전망하였다. 그 결과, 원목수요는 지속적으로 상승하는 것으로 나타났다. 일정한 가격상승률을 전제한 예측수요량이 일정한 가격지수의 상승을 전제한 경우보다 높게 나타났다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.214-221
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• 2018

The purpose of this study is to analyze the shipbuilding structure of field tangerine by ten days and by month. By estimating and analyzing the price flexibility function of field tangerines, this study determines whether the shipment control can stabilize and increase the income of field tangerine farmers and provides policy implication. Considering the overall market, a 1% increase in shipment volume indicates that the coefficient of price flexibility varies with ten days and month. The greatest decline is from late October to early January. Therefore, a greater necessity of shipment control is required during late October and early January. The coefficient of the dummy variable (DUM_Q) indicates the year in which the quality declines is statistically significant and sign. The coefficient of the dummy variable (DUM02) represents the year in which more than 7 days after the New Year holidays are in February is statistically significant and sign from early October to late January. Therefore, it can be seen that the necessity of shipment control is more required when New Year holidays are in February. The greatest decline in the coefficient of price flexibility is from October to December. Therefore, a greater necessity of shipment control is required during October and December. The signs of coefficients of DUM01 and DUM_Q dummy variable of the price flexibility function suggest that the need for shipment control is more important when quality is worse than better quality and that the necessity of shipment control is more required when New Year holidays are in February, respectively.

• Communications for Statistical Applications and Methods
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• v.18 no.4
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• pp.495-505
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• 2011

This study performs statistical tests for stability of a long-run relationship in the telecommunication market system by identifying the time path of a recursively estimated cointegration parameter. A dummy variable is used to recover stability for the period that the hypothesis of stable cointegration is rejected, and then a proper cointegrating relation is derived. A dummy variable appears to reflect the structural change in the cointegrating relation according to the analytical results for the error correction term.

• Korea Real Estate Review
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• v.28 no.3
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• pp.21-35
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• 2018

The recent performance of residential mortgages demonstrated how default risk operated separately from prepayment risk. In this study, we investigated the determinants of the borrowers' decisions pertaining to early termination through default from the mortgage performance data released by Freddie Mac, involving securitized mortgage loans from January 2011 to September 2013. We estimated a Cox-type, proportional hazard model with a single risk on fundamental factors associated with default options for individual mortgages. We proposed a mortgage default model that included two specifications of delinquency: one using a delinquency binary variable, while the other using a delinquency probability. We also compared the results obtained from two specifications with respect to goodness-of-fit proposed in the spirit of Vuong (1989) in both overlapping and nested models' cases. We found that a model with our proposed delinquency probability variable showed a statistically significant advantage compared to a benchmark model with delinquency dummy variables. We performed a default prediction power test based on the method proposed in Shumway (2001), and found a much stronger performance from the proposed model.

• The Korean Journal of Applied Statistics
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• v.22 no.2
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• pp.435-442
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• 2009

Multiple genes interacting is a difficult due to the limitations of parametric statistical method like as logistic regression for detection of gene effects that are dependent solely on interactions with other genes and with environmental exposures. Multifactor dimensionality reduction(MDR) statistical method by dummy variables was applied to identify interaction effects of single nucleotide polymorphisms(SNPs) responsible for longissimus mulcle dorsi area(LMA), carcass cold weight(CWT) and average daily gain(ADG) in a Hanwoo beef cattle population.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.555-561
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• 2019

This study analyzed the shipbuilding structure of House Tangerine over a ten day period and according to the month in Jeju. By estimating and analyzing the price flexibility function of House Tangerine, the aim was to determine if the shipment control can stabilize and increase the incomes of House Tangerine farmers and derive policy implications. The greatest decline in the coefficients of the ten-day price flexibility occurred in the equations from early June to late July. Therefore, the shipment control of House Tangerine is required more during early June and late July. The coefficient of DUM_Q, indicating the year in which the quality of House Tangerine is somewhat deteriorated, was statistically significant and had a (-) sign. The coefficients of DUM_SUK, indicating the year in which Chuseok (Korean Thanksgiving Day) was in October, was statistically significant and had a (-) sign in the middle and late October. The greatest decline in the coefficient of monthly price flexibility function occurred in July, June, and September. Therefore, shipment control is required more in July, June, and September. The (-) signs of the coefficients of DUM_Q and DUM_SUK suggest that the need for shipment control is more important when the quality is less than better quality and that the necessity of shipment control is required more when Chuseok is in October, respectively.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.284-289
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• 2009

This study estimated the fiberboard demand using VAR and econometric model, and compared the prediction accuracy of the two models. And the variance decomposition and impulse response were analyzed using VAR model, and predicted the fiberboard demand. The VAR model was specified with lagged dependent variable, lagged own price, lagged construction product, dummy. The econometric model was specified with own price, substitute price, construction product, dummy. The dummy variable reflected the abrupt decrease in fiberboard demand in the late 1990's. The results showed that the fiberboard demand prediction can be performed more accurately by VAR model than by econometric model. In the VAR model of fiberboard demand, after twelve months, the construction product change accounts for about fifty percent of variation in the demand, and the own price change accounts for about thirty percent of variation in the demand. On the other hand, the impact of a shock to the construction product is significant for about twelve months on the demand of fiberboard, and the impact of a shock to the own price is significant for about six months on the demand of fiberboard.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.287-297
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• 2019

When cryptographic algorithms are implemented to provide countermeasures against the side-channel analysis, designers frequently employ the combined countermeasures between the first-order masking scheme and hiding schemes. Their combination can be enough to offer security and efficiency. However, if dummy operations can be distinguished from real operations, an attacker can extract the secret key with lower complexity than the intended attack complexity by the designer inserting the dummy operations. In this paper, we categorize types of variables used in a dummy operation when C language is employed. Then, we present the novel vulnerability that can distinguish dummy operations for all cases where the hiding schemes are applied using different types of variables. Moreover, the countermeasure is provided to prevent the novel vulnerability.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.6
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• pp.111-122
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• 2016

Support and efforts are being strengthened at the national level for entrepreneurial activities that are expected to revitalize our economy. Generally, according to the previous studies, it is known that entrepreneurship positively affects economic growth and the reduction of unemployment rate through employment creation. The analysis of the impact of entrepreneurial activities on economic growth and job creation is mainly based on national comparative analysis. In this paper, however, the impact of start-up activities in the Busan metropolitan city on regional economic growth and employment improvement. In this study, the dummy variables were assigned to firms within three years, five years, and ten years after start-up according to the period since the start-up of the firm. As a result of the empirical analysis, the value of dummy variable of the start - up firms was found to be significant in the analysis of the sales growth rate as the dependent variable according to the preceding study by Evans(1987). Therefore, it can be seen that the growth rate of the start - up company is higher than that of the other companies and it is positive for the regional economic growth. In addition, the coefficient of the dummy variable decreases from the enterprise analysis to the latter within three years, five years, and ten years after the start-up, and confirms that the coefficient of the firm's start-up years has a negative value. I could see more clearly. On the other hand, in the analysis of the effect of start-up firms on unemployment rate reduction, the growth rate of regular workers was higher than that of other firms. This suggests that it positively affects the reduction of the unemployment rate in the region. In addition, in the dynamic analysis using the Almon estimation formula and the Koyck model, the effect of log-transformed net start-up firms on the growth rate of new workers is very significant. As a result of the above model, It is reaffirmed that start-up activity has a positive effect on employment growth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2096-2109
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• 2012

This study investigates empirical issues that have received little attention in the previous research in the Korean capital market. It is to find any financial determinants on the capital structure for the firms listed in the KOSDAQ(Korea Securities Dealers Automated Quotation). Another test is performed to find any possible discriminating factors by utilizing a robust methodology, which may distinguish between the firms belonging the 'prime section' and the 'venture section' in terms of their financial aspects. Moreover, the null hypothesis that the changing trend or movement of a firm's capital structure with respect to its industry mean (or median) may be random, is also tested. For the book-value based debt ratios, size(INSIZE), growth(GROWTH), Market to book value of equity(MVBV), volatility(VOLATILITY), market value of equity (MVE) and section dummy (SECTION) showed their statistically significant effects on the book-value based leverage ratios, respectively, while size(INSIZE), growth(GROWTH), market value of equity(MVE), beta(BETA) and section dummy (SECTION) showed their statistically significant effects on the market-value based leverage ratios. This study also found an interesting result that a firm belonging to each corresponding industry has a tendency for reversion toward its mean and median leverage ratios over the five-year tested period.