• 한국산림과학회지
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• 제95권5호
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• pp.601-604
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• 2006

This study compared the accuracy of partial multivariate and vector autoregressive models for lumber demand prediction in Korea. The partial multivariate model has three explanatory variables; own price, construction permit area and dummy. The dummy variable reflected the boom of lumber demand in 1988, and the abrupt decrease in 1998. The VAR model consists of two endogenous variables, lumber demand and construction permit area with one lag. On the other hand, the prediction accuracy was estimated by Root Mean Squared Error. The results showed that the estimation by partial multivariate and vector autoregressive model showed similar explanatory power, and the prediction accuracy was similar in the case of using partial multivariate and vector autoregressive model.

• 보건행정학회지
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• 제12권3호
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• pp.54-76
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• 2002

This study investigated how much EVA which evaluate firm's value can explain hospital bankruptcy prediction as a explanatory variable including financial indicators in Korea. In this study, artificial neural network and logit regression which are traditional statistical were used as the model for bankruptcy prediction. Data used in this study were financial and economic value added indicators of 34 bankrupt and -:4 non-bankrupt hospitals from the Database of Korean Health Industry Development Institute. The main results of this study were as follows: First, there was a significant difference between the financial variable model including EVA and the financial variable model excluding EVA in pre-bankruptcy analysis. Second, EVA could forecast bankruptcy hospitals up to 83% by the logistic analysis. Third, the EVA model outperformed the financial model in terms of the predictive power of hospital bankruptcy. Fourth, The predictive power of neural network model of hospital bankruptcy was more powerful than the legit model. After all the result of this study will be useful to future study on EVA to evaluate bankruptcy hospitals forecast.

• Journal of applied mathematics & informatics
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• 제41권6호
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• pp.1341-1364
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• 2023

This article introduces a method for estimating the conditional hazard function of a real-valued response variable based on a functional variable. The method uses local linear estimation of the conditional density and cumulative distribution function and is applied to a functional stationary ergodic process where the explanatory variable is in a semi-metric space and the response is a scalar value. We also examine the uniform almost complete convergence of this estimation technique.

• 응용통계연구
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• 제21권1호
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• pp.1-17
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• 2008

형제 쌍(sibpair)의 연속형 형질(continuous traits) 자료를 이용한 유전연관성 검정 법(linkage test)으로서 Haseman과 Elston (1972)의 최소제곱(ordinary least square, OLS) 회귀분석법이 주로 사용된다. 비모수적 방법으로서 제시된 Kruglyak과 Lander (1995)의 검정통계량은 Haseman과 Elston (1972)의 방법에 대응되는 방법처럼 보이지만 실제로는 매우 다르다. 본 논문에서는 Kruglyak와 Lander (1995)의 검정통계량과 Haseman과 Elston (1972)의 검정통계량의 관계를 설명하고 모의실험으로 두 검정통계량의 검정력을 비교한다. 유전연관성에 사용되는 형제 자료의 특징은 한정된 설명변수의 값에 매우 많은 자료가 반복(replicated)되었다는 점이며, 이러한 반복 자료에 더욱 적절한 가중 회귀분석법을 제안한다. 가중 회귀분석법의 효율성을 정규분포 또는 정규분포가 아닌 연속형 형질 모의실험 자료로 알아본 결과 형제 쌍 자료의 유전연관성 검정에서 가중 회귀분석법이 다른 검정법들보다도 검정력이 높음을 확인하였다.

• 산경연구논집
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• 제10권1호
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• pp.69-76
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• 2019

Purpose - The purpose of this paper is to empirically investigate the effectiveness of Offcial Development Assistance (ODA) in recipient countries' economy. ODA is designed to mitigate poverty and stimulate economic growth in the developing countries. We classify total ODA into bilateral ODA and multilateral ODA depending on the number of donor countries. If the ODA flows from one donor country to one recipient country, it is classified as bilateral ODA. If the multiple countries simultaneously become donor countries through the international organizations such as United Nations and World Bank, it is classified as multilateral ODA. This paper compares the effect of bilateral ODA and multilateral ODA in determining recipient countries' economic development, and tries to provide policy implications to Korean ODA. Research design, data, and methodology - Our primary explanatory variables are bilateral and multilateral ODA. Private credit in recipient countries is adopted as additional explanatory variables to capture the level of financial development in recipient countries. We measure the ODA effectiveness using economic growth and quality of life of the recipient countries as the dependent variable. We collect 142 recipient countries' data from OECD statistics, during the period from 1970-2014. Panel least squares estimation with country fixed effect is employed as the empirical model. Results - Our results support that ODA variable has a negatively significant impact on recipient countries' economic growth, while it is positively correlated with human development index. Recipient countries' private credit is positively correlated with economic growth and human development index. The interaction variable of ODA and financial development turns out to be significant in general. We find that the positive effect of ODA depends on recipient countries' financial market development and this effect is stronger in multilateral aid than bilateral one. Conclusions - From the analysis, we have confirmed that the recipient countries financial development is the necessity condition to achieve positive effect of ODA. Based on these results, we suggest that Korean government should increase the share of multilateral funding and pay attention to recipient countries' financial market development to maximize the effectiveness of ODA.

• 응용통계연구
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• 제16권1호
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• pp.87-100
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• 2003

서로 연관관계에 있는 실제의 통계자료들은 동태적, 확률적 동시발생적으로 유발되며, 이로 인해 한 자료의 변동이 다른 자료에 미치는 영향은 같은 기간 뿐 아니라 시차를 두고 여러 기간에 걸쳐 지속되며 조정되어 간다. 그러나 일반적인 선형, 비선형 통계모형을 사용하여 현실동향을 분석하는 경우 자료의 이러한 특성에서 오는 시차관계를 통상 무시함으로써 변수 사이의 관계는 같은 기간 내에 결정되어야 하는 제약이 가해지게 된다. 그 결과 시간이 흐름에 따라 이들의 관계가 변화하는 과정이나 한 변수의 변동이 다른 변수에 미치는 장기적 영향도 추정할 수 없을 뿐 아니라 현실여건의 변동이나 전개과정을 설명하는 데도 큰 결함을 갖게 된다. 시차관계가 존재하는 변수에 실제 여건에 합당한 시차구조가 설정되면 현실이 정확히 반영되고, 모형에 내재된 변수들의 장단기 변동상황과 동태적 적응과정이 파악됨과 동시에 다양한 분석이 가능해지므로 모형의 활용도는 높아지게 된다.

• 치위생과학회지
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• 제23권4호
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• pp.312-319
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• 2023

Background: Parental attention is crucial for preventing childhood oral diseases. Mothers play a significant role in maintaining their families' oral health, and their educational level influences their children's oral health behaviors. This study investigates the impact of mothers' educational levels on adult oral health behaviors using data from a national survey. Methods: This study employed a cross-sectional analysis of secondary data. The data used were obtained from the 8th Korea National Health and Nutrition Examination Survey. Descriptive statistics were calculated to identify participant characteristics. Next, t-tests and one-way analysis of variance were conducted to examine the effects of the explanatory variables on the distribution of the dependent variable. Finally, logistic regression analysis was used to investigate the influence of the explanatory variable on the dependent variable, using "no education" as the reference value, and calculate the odds ratios. Results: Children of mothers with a college education or higher had a 1.13 times higher likelihood of receiving oral examinations than those whose mothers had no education. Children whose mothers graduated from college or higher had a 2.23 times higher probability of receiving preventative dental treatment than those whose mothers had no education. Children whose mothers graduated from college or higher had a 1.92 times higher probability of receiving scaling than those whose mothers had no education. Children whose mothers graduated from high school had a 1.35 times higher probability of receiving scaling than those whose mothers had no education. Conclusion: Developing oral health programs is important for low-educated and low-income parents to change theirs and their children's oral health behaviors/attitudes. This will help reduce oral health disparities among adults raised by parents of higher and lower socioeconomic statuses. Therefore, a comprehensive approach is essential for adults to maintain good oral health, regardless of variations in their parental educational levels during childhood.

• 응용통계연구
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• 제21권2호
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• pp.301-312
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• 2008

상호정보(mutual information: MI)는 설명변수의 목적변수에 대한 예측정도를 나타내는 척도로서, 목적변수에 대한 설명 변수의 중요도 순위를 구하거나 목적 변수를 잘 설명해주는 설명변수의 집합을 구하는 변수선택문제에 유용하게 사용된다. 본 논문에서는 연속형 설명변수와 범주형 목적변수로 구성된 데이터로부터 결합확률분포를 추정하지 않고도 MI 추정량을 구할 수 있는 Sample-spacing 방법에 대한 연구를 수행하였다. 몬테 칼로 모의 실험과 실제데이터에 대한 실험결과, MI 추정을 위해 Sample-spacing 방법을 사용할 때 m = 1을 사용하면 충분히 신뢰할만한 결과를 얻을 수 있다는 것을 알 수 있었다.

• 대한토목학회논문집
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• 제6권2호
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• pp.45-55
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• 1986

본(本) 연구(硏究)는 도시교통계획(都市交通計劃)에서 장래교통발생예측시(將來交通發生豫測時) 항상 문제(問題)로 되는 설명변수선택(說明變數選擇)의 애매성(曖昧性)을 해결(解決)하기 위하여 교통발생(交通發生)의 설명지표(說明指標)를 제안(提案)하는 동시(同時)에 최량(最良)의 도시교통발생(都市交通發生) Model을 작성(作成)하였다. 제안(提案)된 설명지표(說明指標)를 사용(使用)하여 목적별(目的別) 교통발생중회귀(交通發生重回歸) 모델을 작성(作成)하고, 단일변수(單一變數)로 설명(說明)이 가능(可能)한 것은 교통발생(交通발生)의 비손성(非負性)을 확보(確保)하기 위하여 단회귀(單回歸)모델로 수정(修正)하였다. 그러나 다변수(多變數)가 도입(導入)되어도 설명(說明)이 불충분(不充分)한 목적별(目的別) 교통(交通)(등교집중(等校集中)과 자유목적(自由目的)의 발생(發生)모델)은 동질(同質)의 토지이용활동(土地利用活動)으로부터 발생(發生)하는 교통(交通)의 발생특성(發生特性)이 유이(類似)함에 주목(注目)하여 각(各) zone을 특성별(特性別)로 분류(分類)하고 zone 군별(群別)로 교통발생(交通發生) 모델을 작성(作成)하여 통계적(統計的)으로 유의성(有意性)을 검토(檢討)하였다. 그리고 장래교통발생예측(將來交通發生豫測)은 단순(單純)하면서도 예측정도(豫測精度)의 제고(提高)가 바람직하므로 토지이용활동별(土地利用活動別)로 교통발생원단위(交通發生原單位)를 작성(作成)하고 안정성(安定性)을 고찰(考察)하여 교통발생예측시(交通發生豫測時) 실용가능(實用可能)한 원단위(原單位)를 제안(提案)하였다.

• 수산해양기술연구
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• 제57권3호
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• pp.236-245
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• 2021

In this study, a drifting test using a experimental vessel (2,966 tons) in the northern waters of Jeju was carried out for the first time in order to obtain the fundamental data for drift. During the test, it was shown that the average leeway speed and direction by GPS position were 0.362 m/s and 155.54° respectively and the leeway rate for wind speed was 8.80%. The analysis of linear regression modes about leeway speed and direction of the experimental vessel indicated that wind or current (i.e. explanatory variable) had a greater influence upon response variable (e.g. leeway speed or direction) with the speed of the wind and current rather than their directions. On the other hand, the result of multiple regression model analysis was able to predict that the direction was negative, and it was demonstrated that predicted values of leeway speed and direction using an experimental vessel is to be more influential by current than wind while the leeway speed through variance and covariance was positive. In terms of the leeway direction of the experimental vessel, the same result of the leeway speed appeared except for a possibility of the existence of multi-collinearity. Then, it can be interpreted that the explanatory variables were less descriptive in the predicted values of the leeway direction. As a result, the prediction of leeway speed and direction can be demonstrated as following equations. Ŷ₁= 0.4031-0.0032X₁+0.0631X₂-0.0010X₃+0.4110X₄ Ŷ₂= 0.4031-0.6662X₁+27.1955X₂-0.6787X₃-420.4833X₄ However, many drift tests using actual vessels and various drifting objects will provide reasonable estimations, so that they can help search and rescue fishing gears as well.