• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.297-302
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• 2010

It is very important to know mean and confidence interval of water-quality constituents such as BOD for water-quality control and management of rivers and reservoirs effectively. The mean and confidence interval of BOD at Anseong2 and Hwangguji3 sampling stations which are located at the border of local governments in Anseong Stream were estimated and analyzed in this paper using Bootstrap technique which is one of non-parametric statistics. The results of Bootstrap were compared with arithmetic mean, geometric mean, Biweight method mean as a point estimator and distribution mean came from the appropriate probability distribution of Log-normal. In Bootstrap technique 12 data set was randomly selected in each year and 1000 samples was produced to get parameter of population. Visual Basic for Applications (VBA) of Microsoft Excel was utilized in Bootstrap. It was revealed that the Bootstrap technique can be used to explain more rigorously and robustly the achievement or violation of BOD target concentration in Total Maximum Daily Load (TMDL).

• Research in Mathematical Education
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• v.13 no.2
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• pp.109-122
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• 2009

This study investigates the change in two theoretical constructs, attitudes toward mathematics and mathematics self-efficacy, among college students involved in a learning community model. The case of this study was a developmental mathematics class offered at a historically black college located in the southeastern United States. Subjects included 31 students enrolled in an introductory mathematics course, some of whom participated in a learning community (treatment group). The participants completed mathematics attitudes and mathematics efficacy instruments twice: at the beginning of the semester and again at the end. Data was analyzed using descriptive statistics and a non-parametric statistic. The results showed that students' attitudes toward mathematics and mathematics self-efficacy are strongly correlated; the mathematical problem-solving efficacy changed significantly over time and it is significantly higher in the treatment group than in the control group; and the treatment group produced better outcomes. These findings indicate that a learning community model can increase students' mathematics self-efficacy beliefs. It is recommended that mathematics self-efficacy and attitudes toward mathematics be measured over an extended period of time when a learning community is implemented.

• Journal of applied mathematics & informatics
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• v.32 no.3_4
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• pp.343-357
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• 2014

In many non-life insurance applications past data are given in a form known as the run-off triangle. Smoothing such data using parametric crisp regression models has long served as the basis of estimating future claim amounts and the reserves set aside to protect the insurer from future losses. In this article a fuzzy counterpart of the Hoerl curve, a well-known claim reserving regression model, is proposed to analyze the past claim data and to determine the reserves. The fuzzy Hoerl curve is more flexible and general than the one considered in the previous fuzzy literature in that it includes a categorical variable with multiple explanatory variables, which requires the development of the fuzzy analysis of covariance, or fuzzy ANCOVA. Using an actual insurance run-off claim data we show that the suggested fuzzy Hoerl curve based on the fuzzy ANCOVA gives reasonable claim reserves without stringent assumptions needed for the traditional regression approach in claim reserving.

• Journal of the Korean Society for Library and Information Science
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• v.43 no.1
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• pp.113-133
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• 2009

This study suggests a scheme to activate an e-book service through the analysis on the cause of low usage of the services in academic libraries. The data analysis of e-book circulation records was performed for the purpose of preparing the scheme. Frequency analysis and descriptive statistics were used for basic data analysis. Also, t-test, ANOVA, non-parametric chi-square, and correlation analysis were used to examine whether there are any significant differences between treatment groups divided by gender and major.

• Korean Journal of Radiology
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• v.25 no.7
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• pp.656-661
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• 2024

Evaluating the performance of a binary diagnostic test, including artificial intelligence classification algorithms, involves measuring sensitivity, specificity, positive predictive value, and negative predictive value. Particularly when comparing the performance of two diagnostic tests applied on the same set of patients, these metrics are crucial for identifying the more accurate test. However, comparing predictive values presents statistical challenges because their denominators depend on the test outcomes, unlike the comparison of sensitivities and specificities. This paper reviews existing methods for comparing predictive values and proposes using the permutation test. The permutation test is an intuitive, non-parametric method suitable for datasets with small sample sizes. We demonstrate each method using a dataset from MRI and combined modality of mammography and ultrasound in diagnosing breast cancer.

• The Korean Journal of Applied Statistics
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• v.31 no.1
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• pp.41-65
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• 2018

In Korea, as the mortality rate improves in a shorter period of time than in developed countries, it is important to consider the selection of the time series as well as the model selection in the mortality projection. Therefore, this study proposed a method using the multiple regression model in respect to the selection of the time series period. In addition, we investigate the problems that arise when various time series are used based on the Lee-Carter (LC) model, the kinds of LC model along with Lee-Miller (LM) and Booth-Maindonald-Smith (BMS), and the non-parametric model such as functional data model (FDM) and Coherent FDM, and examine differences in the age-specific mortality rate and life expectancy projection. Based on the analysis results, the age-specific mortality rate and predicted life expectancy of men and women are calculated for the year 2030 for each model. We also compare the mortality rate and life expectancy of the next generation provided by Korean Statistical Information Service (KOSIS).

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1181-1190
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• 2010

When an insurer develops an insurance product, it is very critical to determine reasonable premiums, which is directly related to insurer's profits. There are three methods to determine premiums. Frist, the insurer utilizes premiums paid to the similar cases to the current one. Second, the insurer calculates premiums based on policyholder's past records. The last method is to combine the first with the second one. Based on the three methods, there are two major theories determining premiums, Limited Fluctuation Credibility Theory not based on statistical models and Greatest Accuracy Credibility Theory based on statistical models. There are well-known methods derived from Greatest Accuracy Credibility Theory, such as, Buhlmann model and Buhlmann-Straub model. In this paper, we extend the Buhlmann-Straub model to accommodate the fact that variability grows according to the number of data in practice and suggest a new non-parametric method to estimate the premiums. The suggested estimation method is also applied to the data gained from simulation and compared with the existing estimation method.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.70-77
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• 2017

Dynamic visual acuity is used as an important factor to measure athletic performance in sports field. A study on visual acuity testing system using non-see head mounted display (NST-HMD) was conducted recently. However, the NST-HMD has a problem that the sense of space felt by the subject differs from the actual environment. This is because the view is blocked so that it is only implemented in a virtual space. This paper proposes a dynamic visual acuity testing system using optical see through head mounted display (OST-HMD). To do this, OST-HMD and NST-HMD comparative tests were conducted using existing K-D (King-Devick) charts. Experiments were performed on 30 subjects and their visual acuity was measured and analyzed by parametric statistics and one-sample T-test. The results of the study demonstrate the effectiveness of the proposed OST-HMD. This study is expected to use the visual inspection and training equipment of OST-HMD.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.392-412
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• 2018

Due to the semantic gap problem across different modalities, automatically retrieval from multimedia information still faces a main challenge. It is desirable to provide an effective joint model to bridge the gap and organize the relationships between them. In this work, we develop a deep image annotation and classification by fusing multi-modal semantic topics (DAC_mmst) model, which has the capacity for finding visual and non-visual topics by jointly modeling the image and loosely related text for deep image annotation while simultaneously learning and predicting the class label. More specifically, DAC_mmst depends on a non-parametric Bayesian model for estimating the best number of visual topics that can perfectly explain the image. To evaluate the effectiveness of our proposed algorithm, we collect a real-world dataset to conduct various experiments. The experimental results show our proposed DAC_mmst performs favorably in perplexity, image annotation and classification accuracy, comparing to several state-of-the-art methods.

• Research in Community and Public Health Nursing
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• v.12 no.1
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• pp.202-213
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• 2001

This study was conducted to identify the changes of the relationship among general characteristics, self-efficacy. and self-care of the hypertensives in rural area. For this purpose, self-regulation program was carried at two Community Health Practitioner Post located in the suburbs of Daejeon City from September to November. 1999. Data were analyzed with non-parametric statistics, t-test, pearson correlation. The results were as follows; 1. The level of self-care was significantly different according to sex, status of smoking, and the level of self-efficacy of non-smoker was significantly higher than smoker. 2. After self-regulation program, there were significant positive relationship among self-efficacy, self-care, internal locus control, and negative relationship between perceived barrier and self-care. From these results, it can be concluded that the self-regulation program is an effective nursing strategy to promote self-care performance of hypertensives in rural area, and this program can be recommended for the management of hypertensives.