• Journal of Korean Society of Forest Science
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• v.95 no.2
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• pp.203-208
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• 2006

This study compared the roundwood demand prediction accuracy of econometric and time-series models using Korean data. The roundwood was divided into softwood and hardwood by species. The econometric model of roundwood demand was specified with four explanatory variables; own price, substitute price, gross domestic product, dummy. The time-series model was specified with lagged endogenous variable. The dummy variable reflected the abrupt decrease in roundwood demand in the late 1990's in the case of softwood roundwood, and the boom of plywood export in the late 1970's in the case of hardwood roundwood. On the other hand, the prediction accuracy was estimated on the basis of Residual Mean Square Errors(RMSE). The results showed that the softwood roundwood demand prediction can be performed more accurately by econometric model than by time-series model. However, the hardwood roundwood demand prediction accuracy was similar in the case of using econometric and time-series model.

• Asia-Pacific Journal of Business
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• v.3 no.1
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• pp.29-38
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• 2012

This study aims at evaluating the impact of network formation variables and found to have positive impact on the economic performance and growth of the enterprises. The calucation of the weighted scores of networking statements brought some affirmative results to influence the performance of the enterprises. Through multiple regression and logistic regression models it is identified that network formation variables like service receiving status, consultation of the family, other business dummy and attendance in fair have some significant positive impact both on the growth and performance of the enterprises. In addition to above variables, from the set of enterprise characteristics natural logarithm of the market value of total assets and from the entrepreneurs' characteristics set of variables, schooling year and squared value of the experience have been found to have significant positive impact. Finally, it is concluded in the study that to enhance the performance and growth of the enterprises, government and policy rlated organizations need to consider important variables that have positive impact in supplying the entrepreneurial resources especially, developing the net-working relationship.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3824-3832
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• 2009

Would it be true that cutting off using BLOG in business hour prevents that job performance decreases? Even though it is right, would the worker have different reason of using BLOG according to job characteristic? This is the purpose of this study to search the answers for the questions above. Under the first hypothesis, (factors having the people use BLOG can influence the job satisfaction), independent variable was set to three factors and define as 'Interoperability', 'Informative', 'Amusement' respectively and dependent variable was set to job satisfaction in this study. The result of analyzing this hypothesis was that two factors('Interoperability', 'Informative') haveinfluence on job satisfaction but 'Amusement' factor hadn't any influence on job satisfaction. For another hypothesis, (the factor having the worker use BLOG would have different influence on job satisfaction according to job characteristic), Job characteristic was set to 3 group (fixed/unfixed, individual/co-operational, static/active) in this study and these variables were converted to dummy variable for validating the moderating effect on both variables(independent/dependent). The result of analyzing this hypothesis was that all dummy variables set to 3 groupshadn't any moderating effect on both variables. Because a dummy variable couldn't be contained the job characteristic exactly.

• Journal of Korean Society of Forest Science
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• v.81 no.2
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• pp.124-138
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• 1992

This study was carried out to estimate long-term demand functions, and to project consumption of roundwood to the year 2030, using time series data for the period 1970-1990. Especially, the unique features of this study are in the estimation of demand functions for roundwood by species group and by end-use with help of dummy variables. It also, attempts to show how dummy variables can be utilized for improving the estimation result. The result of this study reveals that hardwood roundwood consumption is being substituted by softwood roundwood due to the rapid increase in the relative price of softwood, and this trend is expected to continue in the near future. The consumption of roundwood by mining industry is projected to fall as the coal :mining is expected to decline. The parametric estimates of timber demand function by species group and by end-use indicate that the demand for timber in Korea is more responsive to the performance of domestic economy as a whole, represented by GDP in this study, than to other variables such as own and substitute prices. The effects of population growth and substitute prices could not be determined.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.3
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• pp.10-18
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• 2001

The purpose of this study is to research the influence of soundscape in the preference of landscape. Specifically, Standards types of communications are applied to the landscape such as artificial waterscapes and natural valley. The spatial image was analyzed by the variables of Kaplan´s information processing model. The level of visual preferences was measured by a type of acoustic information in landscape and media of communication, and these data were analyzed by multiple regression. The results of this study can be summarized as follows; The value of landscape preference was not different from all fluent of coherence, complexity, legibility ,mystery and preference utilized the communication media, but it was different by the type of acoustic information in landscape. These results clearly show the influence of sound affecting decisions of landscape preference. The factors determining the level of landscape preference were found to be coherence, complexity, legibility, mystery and dummy variables of acoustic information in landscape and media od communication. These variables amy be the major factors which must be considered on planning and designing as the functional basis for the quantitative analysis.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.272-274
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• 2001

This paper presents a model for short-term load forecasting using relationship of temperature and load. We made one-day ahead load forecasting model using hourly normalized load and 11 dummy variables that were classified by day characteristics such as day of the week, holiday, and special holiday.

• Human Ecology Research
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• v.53 no.6
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• pp.641-654
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• 2015

This study identifies and tracks changes gender differences in adolescent users' problematic online behavior. This study used Korea Youth Panel Survey (KYPS), which has tracked respondents over 7 years, with self-control theory and social learning theory applied as a theoretical framework. The model included individual-level variables such as self-control and respondent's experience of problematic behavior (offline), as well as socialization variables such as the number close friends who engaged in problematic offline behavior, parent-child relationships, and parental monitoring. Dependent variables included problematic online behavior, unauthorized ID use (ID theft) and cyberbullying (cursing/insulting someone in a chat room or on a bulletin board). Control variables consisted of academic performance, time spent on a computer, monthly household income, and father's educational attainment. Random and fixed effects models were performed by gender. Results supported self-control theory even for the within-level analysis (fixed effects models) regardless of gender, while social learning theory was partially supported. Only peer effects were found significant (except for unauthorized ID use) among girls. Year dummy variables showed significant negative associations; however, academic performance and time spent using computers were significant in some models. Father's educational attainment and monthly household income were found insignificant, even in the random effects models. We also discuss implications and suggestions for future research and policy makers.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.935-946
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• 2016

In this paper, we analyzed wage determinants of the vocational high school graduates utilizing both individual-level and work region-level variables. We formulate the models in the way wage determination has multi-level structure in the sense that individual wage is influenced by individual-level variables (level-1) and work region-level (level-2) variables. To incorporate dependency between individual wages into the model, we utilize hierarchical linear model (HLM). The major results are as follows. First, it is shown that the HLM model is better than the OLS regression models which do not take level-1 and level-2 variables simultaneously into account. Second, random effects on sex, maester dummy and engineering dummy variables are statistically significant. Third, the fixed effects on business hours and mean wage of regular job for level-2 variables are statistically significant effect individual-level wages. Finally, parental education level, parental income, number of licenses and high school grade are statistically significant for higher individual-level wages.

• Journal of Korean Society of Forest Science
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• v.87 no.1
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• pp.40-49
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• 1998

This study aimed to provide a strategy for selecting an adequate combination of growth intervals(i.e. times between age $T_1$ and age $T_2$) to be used to improve the reality of the growth equation through obtaining better precision of parameter estimates. Variety of growth functions were fitted to the data and one equation which best fitted the data was chosen for the analysis. A modified Schumacher projection equation, selected as a best equation, that included dummy variables representing locality as a predictor variable was fitted for basal area and height equations with nonoverlapping growth interval and all possible growth interval data sets of Douglas-fir(Pseudotsuga menziesii Mirb.Franco). The data were measured in all parts of the South Island of New Zealand. It was found that the precision of parameter estimates was increased in both basal area and height equations by using data set which contained a range of measurement intervals from short to long term.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.72
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• pp.139-160
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• 2016

Using the gravity model, this paper analyzes empirically how the world trade in goods is affected by regional trade agreements(RTAs) which have been spreading rapidly since the mid-1990s. This paper attempt to do the panel data analysis about 174 countries during the period of 1994-2008. These panel data include 157 RTAs. It is meaningful that this paper uses comprehensive data to analyze the net effect of regional trade agreements on the global trade volume. This provides a clue as to the answer to the stumbling block debate raised early in the regional trade agreement. Also, confirming how the participation of the WTO affected the trade volume among the member countries, the WTO-related dummy variables are additionally introduced to this gravity model. And as far as we know, the state system-related variables is first considered in this model. This variable reflects the social and cultural environments of countries as the proxy variable representing the sociocultural homogeneity. In all regressions, joining to the WTO and consistency of the state system have a positive effect on increasing the trade volumes between countries. According to the analysis of RTA trade effects, RTAs, on average, increase the volume of trade within the RTA region by 27%~37%, and decrease the volume of trade between the regional and the non-regional nation by 1.2%~3.4%.Therefore, the net effect of regional trade agreements on the promotion of global welfare is positive. For robustness check, we also introduce the interaction term of the dummy variable which reflects the RTA tightening and the continuous variable which reflects the distance effect. As a result, the RTAs alleviate the trade-decreasing effect which is caused by the distance between the countries.