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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Journal of Applied Statistics
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Journal DOI :
The Korean Statistical Society
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Volume & Issues
Volume 17, Issue 3 - Nov 2004
Volume 17, Issue 2 - Jul 2004
Volume 17, Issue 1 - Mar 2004
Selecting the target year
A Study on Spatial and Temporal Distribution of a Pest via Generalized Linear Mixed Models
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 185~196
DOI : 10.5351/KJAS.2004.17.2.185
It is an important research area in Integrated Pest Management System to estimate the pest density within plants, because the artificial controls such as spraying pesticides or biological enemies depend on the information of pest density. This paper studies the population density distribution of two-spotted spider mite in glasshouse roses. As the data were collected repeatedly on the same subject, Subject-Specific and Population Averaged approaches are used and compared.
The Classification of Metabolic Type Using Tissue Mineral Analysis
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 197~204
DOI : 10.5351/KJAS.2004.17.2.197
We have sent the 1000 hair samples to USA and received the results from USA because the programs for the interpretation of Tissue Mineral Analysis (TMA) result is not opened yet in Korea. Therefore, the study will analyze the relationship between the hair for Korean and minerals and make a classification system. To achieve the goal, first of all, we coded the results of patients and classified the analyzed results which are the interrelationship between the minerals and dietary situation and the heavy metals and diseases through the statistical methods. Finally we classified 8 metabolic type using decision tree classifier.
Conjoint Analysis Based on the Chebyshev Estimation, with Application to New Product Development of Cellular Phone
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 205~218
DOI : 10.5351/KJAS.2004.17.2.205
Conjoint analysis is employed to decompose the consumer's preference judgements into the importance of attributes, and to predict the degree of preference for each profile of the products, services, or ideas. It has been widely used in industrial marketing, particularly in the areas of product positioning and new product development. This paper is mainly concerned with the conjoint analysis based on the Chebyshev estimation since the efficiency of the least squares estimator is lower than that of the Chebyshev estimator when the preferences are measured as the rank-order. A case study is performed on the preference for cellular phones. And it is shown that conjoint analysis based on the Chebyshev estimation is superior, in terms of the predictive validity, to one which is based on the least squares estimation.
Prediction Intervals for Nonlinear Time Series Models Using the Bootstrap Method
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 219~228
DOI : 10.5351/KJAS.2004.17.2.219
In this paper we construct prediction intervals for nonlinear time series models using the bootstrap. We compare these prediction intervals to traditional asymptotic prediction intervals using quasi-score estimation function and M-quasi-score estimating function comprising bounded functions. Simulation results show that the bootstrap method leads to improved accuracy. The accuracy of the bootstrap is empirically demonstrated with the consumer price index.
A Development of Cross-Sell Scoring Model
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 229~238
DOI : 10.5351/KJAS.2004.17.2.229
Cross-sell models are used to predict the probability or value of a current customer buying a different product or service from the same company. Selling to current customers is one of the easiest way to increase profits and allows companies to carefully manage offers to avoid over-soliciting and possibly alienating their customers. In this study, by using the real database of an insurance company in Korea, we try to explain the steps of actual data mining process. Especially, this study aims to develop cross-sell models to predict the probability which a current customer of automobile insurance buys long-term insurance product.
Dynamic Integration and Causal Relationships between Stock Price Indexes
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 239~252
DOI : 10.5351/KJAS.2004.17.2.239
It is known that the domestic and the U.S. stock prices tend to move together as those markets are closely interrelated. In this study, cointegration and causal relationships among the four stock price indexes of KOSPI, KOSDAQ, DOWJONES and NASDAQ are carefully investigated for the period of declining stock prices in the long run. When all indexes move in a similar fashion, cointegration does not exist and the causal linkages between the domestic and the U.S. stock prices appear relatively complex. On the other hand, when the domestic and the V.S. stock prices move in a different manner, cointegration exists and the causal relationships appear relatively simple. NASDAQ is apparently found to lead the domestic stock market in both periods, which is consistent with the actual market situation when the If industry is under recession.
Simulation Study for Statistical Methods in Comparing Cure Rates between Two Groups
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 253~267
DOI : 10.5351/KJAS.2004.17.2.253
In some clinical trials, one may see that a significant fraction of patients are cured and their original disease does not recur even after termination of treatment and pro-longed follow-up. This situation occurs frequently in pediatric cancer trials where there are excellent therapeutic results. In such cases, interest concentrated on the difference of cure rates rather than other types of differences in failure distributions. Various authors have investigated the parametric and nonparametric methods for testing the difference of cure rates. In this study, we compare by simulation the power and size of a parametric test and five nonparametric tests in a various range of the alternatives, censoring rates and cure rates. Our objectives are to determine if any test was preferable on the basis of size and power in various situation, and to investigate the effect of the model misspecification.
Asymptotic Relative Efficiency for New Score Functions in Rank Regression Models
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 269~280
DOI : 10.5351/KJAS.2004.17.2.269
We explore the selection of r and s that provides improvement over the Wilcoxon scores under the asymmetric distributions we encounter in practice. We select 0 〈 r 〈 1, s 〉 1 for right-skewed distribution and r 〉 1,0 〈 s 〈 1 for left-skewed distributions from the perspective plots. We also study the association between the desirable r and s and the test statistic for skewness.
Bayesian Change Point Analysis for a Sequence of Normal Observations: Application to the Winter Average Temperature in Seoul
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 281~301
DOI : 10.5351/KJAS.2004.17.2.281
In this paper we consider the change point problem in a sequence of univariate normal observations. We want to know whether there is any change point or not. In case a change point exists, we will identify its change type. Namely, it can be a mean change, a variance change, or both the mean and variance change. The intrinsic Bayes factors of Berger and Pericchi (1996, 1998) are used to find the type of optimal change model. The Gibbs sampling including the Metropolis-Hastings algorithm is used to estimate all the parameters in the change model. These methods are checked via simulation and applied to the winter average temperature data in Seoul.
A Combined Randomized Response Technique Using Stratified Two-Phase Sampling
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 303~310
DOI : 10.5351/KJAS.2004.17.2.303
We suggest a method to procure information from the sensitive population which combine a direct survey method, BB and an indirect survey one, RRT, and a combined estimator that uses the stratified double sampling to estimate the sensitive parameter. We compare the efficiency of our estimator with that of Mangat and Singh model.
Analysis of Two Bottleneck ECN/RED Gateways in Many User TCP Networks
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 311~326
DOI : 10.5351/KJAS.2004.17.2.311
We propose a Markov model of two bottleneck ECN/RED gateways experiencing a large number of TCP users. We show that, as the number of users becomes large, the queue sizes per user of the both gateways converge at steady-state to individual fixed points. Also, we derive a computational algorithm to exactly obtain the fixed points and present simulation example showing the limiting behavior of the gateway traffic.
On the Efficiency of Outlier Cleaners in Spatial Data Analysis
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 327~336
DOI : 10.5351/KJAS.2004.17.2.327
Many researchers have used the robust variogram to reduce the effect of outliers in spatial data analysis. Recently it is known that estimating the variogram after replacing outliers is more efficient. In this paper, we suggest a new data cleaner for geostatistic data analysis and compare the efficiency of outlier cleaners.
Testing Independence in Contingency Tables with Clustered Data
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 337~346
DOI : 10.5351/KJAS.2004.17.2.337
The Pearson chi-square goodness-of-fit test and the likelihood ratio tests are usually used for testing independence in two-way contingency tables under random sampling. But both of these tests may provide false results for the contingency table with clustered observations. In this case we consider the generalized linear mixed model which includes random effects of clustering in addition to the fixed effects of covariates. Both the heterogeneity between clusters and the dependency within a cluster can be explained via generalized linear mixed model. In this paper we introduce several types of generalized linear mixed model for testing independence in contingency tables with clustered observations. We also discuss the fitting of these models through a real dataset.
A Study on Selection of Split Variable in Constructing Classification Tree
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 347~357
DOI : 10.5351/KJAS.2004.17.2.347
It is very important to select a split variable in constructing the classification tree. The efficiency of a classification tree algorithm can be evaluated by the variable selection bias and the variable selection power. The C4.5 has largely biased variable selection due to the influence of many distinct values in variable selection and the QUEST has low variable selection power when a continuous predictor variable doesn't deviate from normal distribution. In this thesis, we propose the SRT algorithm which overcomes the drawback of the C4.5 and the QUEST. Simulations were performed to compare the SRT with the C4.5 and the QUEST. As a result, the SRT is characterized with low biased variable selection and robust variable selection power.
Can Statistics Departments Survive in Crisis of Universities in the Local Region\ulcorner
Korean Journal of Applied Statistics, volume 17, issue 2, 2004, Pages 359~371
DOI : 10.5351/KJAS.2004.17.2.359
The goal of this article is to examine the problems and crisis of statistics departments, and to explore the means of settlement.