• Communications for Statistical Applications and Methods
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• 제14권2호
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• pp.443-457
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• 2007

This paper deals with the problem of testing the existence of change in mean and estimating the change-point using nonparametric bootstrap technique. A test statistic using Gombay and Horvath (1990)'s functional form is applied to derive a test statistic and nonparametric change-point estimator with bootstrapping idea. Achieved significance level of the test is calculated for the proposed test to show the evidence against the null hypothesis. MSE and percentiles of the bootstrap change-point estimators are given to show the distribution of the proposed estimator in simulation.

• Journal of the Korean Statistical Society
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• 제30권1호
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• pp.1-20
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• 2001

We present how bootstrap methods can be used to conduct inference on the rates of Poisson distributions when only the grouped data are available. A theoretical justification for the validity of bootstrap is given with an illustration of proposed method using a data set obtained fro ma pathology laboratory test. Traditional asymptotic methods are compared with bootstrap methods in computing the estimated standard errors and achieved significance levels for one sample and two sample tests. Bootstrap methods are shown to possess a nice property that he small sample distribution of the relevant statistics can be readily obtained from the bootstrap copies.

• 농촌지도와개발
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• 제8권2호
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• pp.179-190
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• 2001

The purpose of this study was to analysis the education effects of web-based on-line cyber program mesaured by Kirkpatrick’s evaluation process. The average score on satisfaction of the program was 4.28(.59), which was designed to evaluate the level 1, reaction. To test level 2, learning, the average score that students achieved was calculated and it was 86.87(std.=7.05) in the term examinations. The level 3, job months. It was reported that most employees who took the course are utilizing the knowledge that they acquired from the course(mean=3.80, std.=.77). To identify the level 4, business results, the mean score of the number of accidents and near misses that happened in their factories for 3 months before and after the course were compared. There was statistically significant difference between the number of accidents that happened 3 months before the course and 3 months after the course, at the significance level of .01, which was tested by Paired t-test.

• Communications for Statistical Applications and Methods
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• 제17권3호
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• pp.459-471
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• 2010

일반적으로 고객들은 어떤 상품에 대한 품질수준이 높을수록 보다 높은 만족을 얻는 것으로 알려져 있다. 보통품질수준은 공정능력지수에 의해 측정된다. 공정능력이란 공정이 관리상태에 있을 때, 그 공정에서 생산, 제공되는 상품의 변동이 어느 정도인가를 나타내는 중요한 개념이다. 3세대 공정능력지수 $C_{pmk}$는 흔히 현장에서 사용되고 있는 지수$C_p$나$C_{pk}$보다 공정능력을 평가함에 보다 설명력이 있고 합리적인지수라고 할 수 있다. 공정능력에 대한 효율성 평가는 대부분 점추정과 구간추정을 통하여 행하여지고 있는 바, 가설검정을 통한 의사결정 또한 중요한 문제라고 할 수 있다. 본 논문에서는 공정능력여부를 결정하기위하여 공정능력지수 $C_{pmk}$에 대한 보다 유용한 가설검정방법에 대하여 연구하였다. 제안된 붓스트랩 가설검정방법은 공정분포가 정규분포에 따르던 그렇지 않던지 간에 매우 유용하며 보다 수월하게 활용할 수 있음을 밝혔다. 그리고 수치적인 모의실험을 통해 공정의 정규성 여부와 상관없이 제안된 가설검정방법의 타당성을 밝히고자 하였다.

• 한국융합학회논문지
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• 제13권5호
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• pp.237-247
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• 2022

본 연구는 급속한 고령화 시대에서 우리나라의 고령층의 경제활동 수준을 다양한 머신러닝 기법으로 정확히 예측하고자 하였다. 고령층의 경제활동 수준과 기존 연구들은 고령층의 삶의 만족도, 사회보장제도 등과 연관된 인과성 검증을 중심으로 이루어진 데 반해, 본 연구는 다양한 머신러닝 기법으로 고령층의 경제활동 수준을 예측하였으며, 특히 예측조합법을 함께 사용함으로써 예측의 안정성을 도모하였다. 60세 이상의 경제활동참가율, 취업률 등을 종속변수로 하고 가구 특성, 소득, 평균임금 등을 설명변수로 설정하여 서로 다른 특성을 지닌 5가지의 머신러닝 기법과 2가지의 예측조합법을 적용하여 예측결과들을 비교하였다. 분석 결과, 종속변수별, 예측구간별로 예측성능이 높은 머신러닝 기법 및 예측조합법은 상이하였으나, 예측의 안정성 측면에서는 예측조합법이 상대적으로 우수한 것으로 나타났다. 이에 따라, 본 연구는 고령층의 경제활동 수준을 정확히 예측하고 예측의 안정성을 도모하여 정책적 관점에서도 실용성을 제고한다고 볼 수 있다.

• 한국치위생학회지
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• 제10권4호
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• pp.635-644
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• 2010

Objectives : The purpose of this study was to analyze and investigate the effecting factors on the actual condition of dental clinic use of the out patient. Methods : In oder to achieve this purpose, A survey for 302 patients in 6 participating dental clinics located in Daejeon metropolitan city from May 01 to May 30, 2010. The result of this study was as follows. Results : 1. The duration of dental clinic use was reflected in 36.1% of the under 1 year, 34.1% of over 2 years, and 29.8% of over 1 ~ under 2 years in order. Especially, the higher the duration of over 2 years the higher the age was, on married group had a significance. 2. The type of medical examination for samples was 27.6% of periodontal, 26.5% of conservative, 17.2% of prosthodontics, 10.9% of implant, and 7.9% of preventive in order. Especially, the male group the more the prosthodontics, implant had a significance. the higher the monthly income, on married group, the more the periodontal, prosthodontics and implant had a significance. 3. The motive of dental clinic selection was 38.4% of acquaintances' inducement, 33.4% of the superb treatment, 15.6% of easy convenience, and 7.0% of friendliness staff in order. Especially, male group the more the easy convenience, superb treatment, friendliness staff had a significance. 4. The mean of transportation in order to visit a dental clinic was 38.7% of public transportation, 37.5% of the own car, 23.8% of others in order. Especially, there was a highly significant difference on the public transportation in female, the lower education level, lower monthly income, and medical protection group. 5. The duration of time required of dental clinic reflected in 80.1% of the under 30 minute, 16.3% of over 30 minute~under 1 hour, and 3.6% of over 1 hour in order. Especially, the higher the treatment satisfaction, the dissatisfaction the higher the duration of time required under 30 minute had a significance. Conclusions : These results indicate that as medical services upgrade and get more varied, the expectation of medical quality also increases. It is thus considered that the revitalization of this hospital's management strategy can be achieved by providing highly developed medical services, and, more importantly, by better understanding the actual conditions of dental clinic use by the patients themselves.

• Journal of Periodontal and Implant Science
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• 제23권3호
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• pp.359-373
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• 1993

The ultimate objective of periodontal therapy is not only stopping the progression of periodontal disease, but also promoting the regeneration of lost periodontal tissue. Guided Tissue Regeneration, which is based on the principle that the goal of periodontal regeneration can be achieved by preventing apical migration of gingival epithelium and blocking cells originating from connective tissue, has been developed and used as a clinical procedure, and although it has shown excellent results in connective tissue healing, there have not been many studies showing its effect on the regeneration of alveolar bone loss due to periodontal disease. The objectives of this study are to investigate the result of 12 months-long treatment following guided tissue regeneration using expanded polytetrafluoroehylene membrane, and to observe the presence of regenerated alveolar bone. Forty-one teeth from 28 patients with clinical diagnosis of periodontitis has been selected. In fifteen of those interproximal intrabony defects, only flap operation had been carried out, and designated as the control group. Twenty-six intrabony defects received e-PTFE membrane following flap operation, and designated as the experimental group. Eleven teeth whose membrane had been exposed were excluded from the experiment. Various measurements including probing depth, loss of attachment, probing bone level and gingival recession have been recorded at 6th month and 12th month, and the significance of the changes has been analyzed. The results are as follows: 1. Probing depth at 6th and 12th month has shown a significant decrease in both groups (p<0.01), but significantly higher decrease was found in the experimental group compared to the control at the month(p<0.05). 2. Loss of attachment at 6th and 12th month has shown a significant decrease in both groups, but significantly higher decrease was found in the experimental group compared to the control (p<0.05). 3. Probing bone level at 6th and 12th month has shown a insignificant decrease in the control group and significant decrease in the experimental group (p<0.01). Significantly higher decrease in probing bone level was found in the experimental group (p<0.05). 4. Gingival recession at 6th and 12th month has shown a statistically significant increase (p<0.05), and the control group showed higher increase compared to the experimental group although no statistical significance was found. As these results have shown, the use of e-PTFE membrane in intrabony pockets results in marked decrease in the loss of attachment and probing bone level. This seems to indicate that e-PTFE membrane may play a role in alveolar bone regeneration in intrabony defects.

• Clinical and Experimental Pediatrics
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• 제59권9호
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• pp.362-367
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• 2016

Purpose: This study aimed to investigate the clinical significance of serum alanine aminotransferase (ALT) levels in children with nonalcoholic fatty liver disease (NAFLD) and the effect of lifestyle intervention on NAFLD. Methods: The clinical data of 86 children diagnosed with NAFLD were reviewed retrospectively. Forty-six patients belonged to the elevated ALT group and 40 to the normal ALT group. The clinical parameters of patients with NAFLD were also compared based on the status of ALT levels after lifestyle intervention. Results: Patients with elevated ALT had significantly higher body mass index (BMI) scores than those with normal ALT (P<0.05). Of all the patients with elevated ALT, 89% exhibited moderate or severe degree of fatty change in the liver on ultrasonographic examination, whereas most patients with normal ALT exhibited mild or moderate degree changes. Liver biopsy was performed in 15 children with elevated ALT and all showed mild histological changes. Of all patients with elevated ALT, 49% achieved normal ALT levels after lifestyle intervention. Those with more severe histological changes tended to have continuously increasing ALT levels. There was no correlation between the normalization of posttreatment ALT level and BMI, as well as ultrasonographic findings at diagnosis. Conclusion: ALT elevation in NAFLD is highly associated with higher BMI scores and more severe degree of fatty changes on ultrasonographic examination. Lifestyle intervention can significantly improve ALT in children with NAFLD. The degree of histologic changes appears to be a predictor of the treatment response to NAFLD.

• 지식경영연구
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• 제18권3호
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• pp.101-124
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• 2017

Recently, 'happiness' has become a major issue of national level, exceeding the matter of personal issue. Especially, Korea has actually increased its GDP by focusing on the economic growth for decades, and now it has achieved the economic/technical development as an IT power. However, Korean people's satisfaction with life called 'happiness index' is moving back every year. Even though there have been continuous efforts to enhance the national happiness by mentioning it as an essential issue in the national level, there are not many researches related to it. This study drew measures to enhance happiness by extracting happiness factors and unhappiness factors of Korea through social network service. Especially, it aims to analyze, compare, and apply happiness factors and unhappiness factors of three countries such as the US, UK, and Brazil with higher happiness indexes than Korea. For this, through the topic modeling of text mining technique, postings including keywords about happiness and unhappiness were collected/analyzed from Twitter of Korea, the US, UK, and Brazil. The significance of this study is to discuss measures to increase happiness and to decrease unhappiness by mining/analyzing the actual public opinions about happiness and unhappiness in four countries like Korea, the US, UK, and Brazil by using the topic modeling. Through this, the quality of life of Korean people could be improved by suggesting measures to enhance happiness and to decrease unhappiness in the level of individual, family, society, and government.

• Human Ecology Research
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• 제60권3호
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• pp.331-344
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• 2022

The purpose of this study was to identify a support method for the introduction of metaverse-based classes (MBC) in home economics (HE) education. This was achieved by diagnosing the stages of concern and levels of use exhibited by HE teachers applying the concerns-based adoption model (CBAM). Questionnaires were sent to a convenience sample of middle- and high-school HE teachers using the KSDC (Korea Social Science Data Center). Overall, 271 responses were received, and the data were analyzed using KSDC E-STAT 3.0 and SPSS 28.0.1.1. The results were as follows: First, regarding the level of knowledge of MBC, the introductory level was the most common (139 respondents, 51.3%,), followed by the beginner level (81, 29.9%), the intermediate level (28, 10.3%,), the advanced level (12, 4.4%), and the master level (11, 4.1%). Average responses on a 5-point Likert scale to questions about the use of metaverse in HE classes were as follows: possibility (4.02), necessity (3.82), and usefulness (3.90). Second, HE teachers' stages of concern in MBC were as follows (in descending order): unconcerned - stage 0, and information - stage 1 (86.9), personal - stage 2 (85.6), management - stage 3 (80.9), collaboration - stage 5 (57.5), consequence - stage 4 (57.4), and refocusing - stage 6 (55.2). Third, the use of MBC was highest for orientation - level 1 (173 respondents, 63.8%), followed by non-use - level 0 (34, 12.5%), preparation - level 2 (29, 10.7%), mechanical - level 3 (15, 5.5%), refinement - level 5 (8, 3.0%), renewal - level 7 (8, 3.0%), routine - level 4 (3, 1.1%), and integration - level 6 (1, 0.4%). Many HE teachers had heard about MBC but were in the introductory level of not knowing what it is, and at the stage of being unconcerned or wanting to know about MBC. Of the 271 respondents, only 35 used metaverse in classes. Therefore, it is necessary to provide teacher training opportunities that provide basic information on the significance and implementation of MBC for HE teachers. Also, an MBC guideline book should be developed and distributed to HE teachers. Finally, a teacher community meeting is needed to share the expertise of teachers with substantial experience in using MBC.