• 한국환경과학회지
• /
• 제22권8호
• /
• pp.953-963
• /
• 2013

Reliable long-term streamflow forecasting is invaluable for water resource planning and management which allocates water supply according to the demand of water users. Forecasting of seasonal inflow to Andong dam is performed and assessed using statistical methods based on hydrometeorological data. Predictors which is used to forecast seasonal inflow to Andong dam are selected from southern oscillation index, sea surface temperature, and 500 hPa geopotential height data in northern hemisphere. Predictors are selected by the following procedure. Primary predictors sets are obtained, and then final predictors are determined from the sets. The primary predictor sets for each season are identified using cross correlation and mutual information. The final predictors are identified using partial cross correlation and partial mutual information. In each season, there are three selected predictors. The values are determined using bootstrapping technique considering a specific significance level for predictor selection. Seasonal inflow forecasting is performed by multiple linear regression analysis using the selected predictors for each season, and the results of forecast using cross validation are assessed. Multiple linear regression analysis is performed using SAS. The results of multiple linear regression analysis are assessed by mean squared error and mean absolute error. And contingency table is established and assessed by Heidke skill score. The assessment reveals that the forecasts by multiple linear regression analysis are better than the reference forecasts.

• Journal of the Korean Data and Information Science Society
• /
• 제24권6호
• /
• pp.1465-1475
• /
• 2013

The chi-square type test statistic is the most commonly used test in terms of measuring testing goodness-of-fit for multinomial logistic regression model, which has its grouped data (binomial data) and ungrouped (binary) data classified by a covariate pattern. Chi-square type statistic is not a satisfactory gauge, however, because the ungrouped Pearson chi-square statistic does not adhere well to the chi-square statistic and the ungrouped Pearson chi-square statistic is also not a satisfactory form of measurement in itself. Currently, goodness-of-fit in the ordinal setting is often assessed using the Pearson chi-square statistic and deviance tests. These tests involve creating a contingency table in which rows consist of all possible cross-classifications of the model covariates, and columns consist of the levels of the ordinal response. I examined goodness-of-fit tests for a proportional odds logistic regression model-the most commonly used regression model for an ordinal response variable. Using a simulation study, I investigated the distribution and power properties of this test and compared these with those of three other goodness-of-fit tests. The new test had lower power than the existing tests; however, it was able to detect a greater number of the different types of lack of fit considered in this study. I illustrated the ability of the tests to detect lack of fit using a study of aftercare decisions for psychiatrically hospitalized adolescents.

• 한국통계학회:학술대회논문집
• /
• 한국통계학회 2005년도 추계 학술발표회 논문집
• /
• pp.31-36
• /
• 2005

An identification and characterization of susceptibility genes for common complex multifactorial diseases is a challengeable task, in which the effect of single genetic variation will be likely dependent on other genetic variations(gene-gene interaction) and environmental factors (gene-environment interaction). To address is issue, the multifactor dimensionality reduction (MDR) has been proposed and implemented by Ritchie et al. (2001), Moore et al. (2002), Hahn et al.(2003) and Ritchie et al. (2003). With MDR, multilocus genotypes effectively reduce the dimension of genotype predictors from n to one, which improves the identification of polymorphism combinations associated with disease risk. However, MDR cannot handle missing observations appropriately, in which missing observation is treated as an additional genotype category. This approach may suffer from a sparseness problem since when high-order interactions are considered, an additional missing category would make the contingency table cells more sparse. We propose a new MDR approach with minimum loss of sample sizes by considering missing data over all possible multifactor classes. We evaluate the proposed MDR by using the prediction errors and cross validation consistency.

• 산업경영시스템학회지
• /
• 제30권2호
• /
• pp.89-98
• /
• 2007

In this paper the economic value of weather forecasts is valuated for profit-oriented enterprise decision-making situations. Value is estimated in terms of monetary profits (or benefits) resulted from the forecast user's decision under the specific payoff structure, which is represented by a profit/loss ratio model combined with a decision function and a value score (VS). The forecast user determines a business-related decision based on the probabilistic forecast, the user's subjective reliability of the forecasts, and the payoff structure specific to the user's business environment. The VS curve for a meteorological forecast is specified by a function of the various profit/loss ratios, providing the scaled economic value relative to the value of a perfect forecast. The proposed valuation method based on the profit/loss ratio model and the VS is adapted for hypothetical sets of forecasts and verified for site-specific probability of precipitation forecast of 12 hour and 24 hour-lead time, which is generated from Korea meteorological administration (KMA). The application results show that forecast information with shorter lead time can provide the decision-makers with great benefits and there are ranges of profit/loss ratios in which high subjective reliability of the given forecast is preferred.

• The Korean Journal of Ecology
• /
• 제9권3호
• /
• pp.135-147
• /
• 1986

The simplification and the searching trends of complex data which assumed relationship between predictor variables and object variables are one of primary objective of ecological research. This study was aimed to apply cononical analysis consisting of canonical correlation analysis and canonical variate analysis related to lichen vegetation and several environmental variables which are elevation, height on grond, exposure side and cover values. Data collected from the Duckyoo National Park in August 1985. Lichen species was ranked by eqivocation information theory with cover values. Canonical correlation analysis was applied to one data set both set both environmental variables and lichem family. In order to make two sets of data matrix the scale of position vector ordination was calculated from the vector scalar product for lichen species. Canonical variate analysis was applied to rearranged data which was made by interval class code for environmental variables. The sharpness values was calculated in frequency of cotingency tables and the dispersion profiles of each species in classes of environmental variables was designed to extract component values based on the decomposition of expected frequencies in contingency table. The results of canonical correlation analysis revealed canonical first correlation value 0.815(89%), and second correlation value 0.083(11%). Significance test showed that the hypothesis of joint mutuallity of canonical correlation is accepted (P>0.05). The relation between canonical score of vegetation variables and that of environmental variable indicated linear tendency.

• Journal of the Korean Data and Information Science Society
• /
• 제10권1호
• /
• pp.29-36
• /
• 1999

분할표 분석에서 승산비 (odds ratio)에 대한 추론은 중요하다. 이에 대한 정확한 추론은 비중심초기하(noncentral hypergeometric) 분포의 누적확률등의 계산이 요구되어 표본의 크기가 클 경우 많은 양의 계산과 계산시간이 요구되므로 StatXact 등의 프로그램을 이용하는 것이 일반적이다. 본 논문에서는 정확한 추론에 대한 대안적 방법으로 안부점 근사(saddlepoint approximation)의 결과를 이용한 점근적 추론법을 제시하였다. 이 방법은 비교적 소표본의 경우에도 정확한 추론의 결과와 일치하며, 기존의 정규근사를 이용한 방법에 비해 매우 뛰어난 정확도를 유지함을 예제를 통해 확인하였다.

• Journal of the Korean Data and Information Science Society
• /
• 제21권6호
• /
• pp.1203-1209
• /
• 2010

한국정보화진흥원에서는 2002년 개발한 한국형 인터넷 중독 진단척도를 사용하여 인터넷 중독 실태를 매년 발표하고 예방을 위해 노력하고 있다. 그러나 인터넷사용이 급증함에 따라 정보화의 역기능도 증가하고 있으며 특히 인터넷 중독의 폐해가 우려되고 있는 실정이다. 본 연구에서는 인터넷 중독 자가진단 소형척도를 제안하고자한다. 대학생들을 대상으로 킴벌리영척도와 한국형진단척도를 적용하여 인터넷 중독을 진단한 자료를 분석한다. 두 척도의 신뢰성과 타당성을 검토한 결과 한국형진단척도에서 요인타당도가 있음으로, 이를 이용하여 소형척도를 개발한다. 요인타당도의 요인적재값과 변수선택법을 이용하여 선택한 소형척도들을 비교 분석한다. 분할표와 감마 연관성측도를 이용하여 소형척도와 기존의 척도들과의 일치성을 비교하고, 소형척도들의 신뢰성과 타당성을 조사한다.

• 한국지구과학회지
• /
• 제25권1호
• /
• pp.10-21
• /
• 2004

Recently, spatial data integration for geoscientific application has been regarded as an important task of various geoscientific applications of GIS. Although much research has been reported in the literature, quantitative assessment of the spatial interrelationship between input data layers and an integrated layer has not been considered fully and is in the development stage. Regarding this matter, we propose here, methodologies that account for the spatial interrelationship and spatial patterns in the spatial integration task, namely a multi-buffer zone analysis and a statistical analysis based on a contingency table. The main part of our work, the multi-buffer zone analysis, was addressed and applied to reveal the spatial pattern around geological source primitives and statistical analysis was performed to extract information for the assessment of an integrated layer. Mineral potential mapping using multi-source geoscience data sets from Ogdong in Korea was applied to illustrate application of this methodology.

• 한국의상디자인학회지
• /
• 제9권3호
• /
• pp.87-97
• /
• 2007

This study is to investigate the KS size recognition and mother's preference of female children's apparel. The practical research is performed for 150 mothers lived in Seoul and are randomly selected to their age, female children's number, education and income level. For statistical analysis and evaluation of survey data, frequency and percentage use contingency table. Findings in this study as follow: 1. Mother's preference for purchasing the girl's garments shows the significant differences of their subject characteristics such as age, girl's number, education and income level. 2. Mother's recognition about KSK 9403: 2004 sizing system for girl's garments does not show the significant differences of their subject properties. Most mothers only know the part of the KS size specifications because KS sizing systems are complex. So KS sizing systems must be simplified and respecified to understand the KS for mothers easily when purchasing their girl's garments. In summary this paper investigates mother's preference and recognition about KS sizing system for the girl's garments.

• 성인간호학회지
• /
• 제21권6호
• /
• pp.559-569
• /
• 2009

Purpose: This study was to examine the reliability and validity of Patient-Generated Subjective Global Assessment (PG-SGA) as a nutritional measurement for stroke patients. Methods: This was a methodological study performed from May 6 to June 10, 2009 at a tertiary university hospital in Seoul. For reliability of PG-SGA, inter-rater reliability was used for statistics. For concurrent validity, BMI and biomarkers were compared between PG-SGA 0 ~ 8 and ${\geq}$ 9. In addition, sensitivity, specificity, and predictive value of PG-SGA compared with SGA were calculated using a contingency table. For predictive validity, hospital day, complications, and readmission within 1-month after discharge were compared between PG-SGA 0 ~ 8 and ${\geq}$ 9. Results: Correlation of PG-SGA score between two observers was 0.83, and kappa value for the agreement of severe malnutrition was 0.78(all $p_s$ < .001). The scored PG-SGA showed high sensitivity and specificity (100% and 96.7%, respectively). Severe undernourished patients (PG-SGA ${\geq}$ 9) had significantly low TLC, protein, albumin, and prealbumin (all $p_s$ < .01) compared with non-undernourished patients (PG-SGA 0 ~ 8). Also, in severe undernourished patients, complications and readmission (all $p_s$ = 0.01) were more often represented, and hospital days (p = .013) were significantly delayed. Conclusion: PG-SGA is a reliable and valid measurement to assess nutritional status for stroke patients.