• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1008-1011
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• 2001

The purpose of this paper is to evaluate the chip breakability during turning using the experimental equation, which is developed by an orthogonal array method. The chip breaking index(CB), non-dimensional parameter is used in the evaluation of chip breakability. The analysis of variance(ANOVA)-test has been used to check the significance of cutting parameters. And using the result of ANOVA-test, the experimental equation of chip breakability, which consists of significant cutting parameters, has been developed.

• Journal of Welding and Joining
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• 제15권1호
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• pp.66-80
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• 1997

This paper describes a newly developed arc-sensing algorithm of seam-tracking for FCA W (flux-cored arc welding) horizontal fillet welding. In this algorithm, arc current and the Weighted-Are-Current (WAC) are used to adjust the position of a weld torch in directions of bead throat and weaving, respectively. The WAC, which is newly devised in this study, means that arc current in the vicinity of weaving end is more emphasized than that in the center of weaving. The reason of this is because there usually exists much noise in the center of weaving due to abrupt change of arc length in case some empty gaps exist in a fillet joint Variance analysis was performed in order to check the effect of weld parameters on arc current and the WAC. As a result, the relationships between tip-to-workpiece distance and arc current, and between weaving offset and the WAC were established.To check "the validity of the algorithm, seam-tracking experiments were performed ;mder various welding condition. The result of experiments showed a satisfactory tracking performance in the presence of empty gaps in a horizontal fillet joint.et joint.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.862-865
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• 2000

The object of this paper is to evaluate the surface roughness using the experimental equation of surface roughness, which is developed in turning by an orthogonal array method. $L_9{3^4}$ orthogonal array method, one of fractional factorial design has been used to study effects of main cutting parameters such as cutting speed, feed rate and depth of cut, on the surface roughness. And the analysis of variance (ANOVA)-test has been used to check the significance of cutting parameters. Using the result of ANOVA-test, the experimental equation of surface roughness, which consists of only significant cutting parameter - feed rate, has been developed. The coefficient of determination of this equation is 0.962.

• Journal of Welding and Joining
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• 제15권6호
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• pp.66-77
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• 1997

In the present work, Taguchi method for electron beam welding(EBW) process in AISI 4130 steel plate has been adopted for investigating the contribution of effect of welding variables. $A L_8(2^7)$ orthogonal array is adopted to obtain the effect of adjustment parameters. The adjustment parameters consist of accelerating voltage, beam current, travel speed and focus currrent. And the quality features selected for the EBW process are bead width of weldment, reinforcement, penetration depth, undercut and area of weld metal. Variance analysis is performed in order to check the effect of adjustment parameters on EBW. The mechanical properties of electron beam welded joints for each heat treatment conditions are investigated in comparison with those of base metal, especially from the view point of tensile and impact properties.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2012년 춘계학술대회
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• pp.579-583
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• 2012

The Design of Experiment (DOE) is a most practical technique when establishing an optimal condition for production technology in Six Sigma innovation project. This research proposes the assessment of properties of error terms, such as normality, equal variance, unbiasedness and independence. The properties of six nonparametric ranking techniques for checking normality assumption are discussed as well as run test which is used to identify the randomness, and to check unbiased assumption. Furthermore, Durbin-Watson (DW) statistics and ARIMA (p,d,q) process are discussed to identify the serial correlation.

• ETRI Journal
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• 제37권4호
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• pp.752-765
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• 2015

We propose a novel post-processing algorithm and its very-large-scale integration architecture that simultaneously uses the passive and active stereo vision information to improve the reliability of the three-dimensional disparity in a hybrid stereo vision system. The proposed architecture consists of four steps - left-right consistency checking, semi-2D hole filling, a tiny adaptive variance checking, and a 2D weighted median filter. The experimental results show that the error rate of the proposed algorithm (5.77%) is less than that of a raw disparity (10.12%) for a real-world camera image having a $1,280{\times}720$ resolution and maximum disparity of 256. Moreover, for the famous Middlebury stereo image sets, the proposed algorithm's error rate (8.30%) is also less than that of the raw disparity (13.7%). The proposed architecture is implemented on a single commercial field-programmable gate array using only 13.01% of slice resources, which achieves a rate of 60 fps for $1,280{\times}720$ stereo images with a disparity range of 256.

• Communications for Statistical Applications and Methods
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• 제31권1호
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• pp.1-35
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• 2024

The assumption of homoscedasticity is one of the most crucial assumptions for many parametric tests used in the biological sciences. The aim of this paper is to compare the empirical probability of type I error and the power of ten parametric and two non-parametric tests for homoscedasticity with simulations under different types of distributions, number of groups, number of samples per group, variance ratio and significance levels, as well as through empirical data from an agricultural experiment. According to the findings of the simulation study, when there is no violation of the assumption of normality and the groups have equal variances and equal number of samples, the Bhandary-Dai, Cochran's C, Hartley's Fmax, Levene (trimmed mean) and Bartlett tests are considered robust. The Levene (absolute and square deviations) tests show a high probability of type I error in a small number of samples, which increases as the number of groups rises. When data groups display a nonnormal distribution, researchers should utilize the Levene (trimmed mean), O'Brien and Brown-Forsythe tests. On the other hand, if the assumption of normality is not violated but diagnostic plots indicate unequal variances between groups, researchers are advised to use the Bartlett, Z-variance, Bhandary-Dai and Levene (trimmed mean) tests. Assessing the tests being considered, the test that stands out as the most well-rounded choice is the Levene's test (trimmed mean), which provides satisfactory type I error control and relatively high power. According to the findings of the study and for the scenarios considered, the two non-parametric tests are not recommended. In conclusion, it is suggested to initially check for normality and consider the number of samples per group before choosing the most appropriate test for homoscedasticity.

• 대한통합의학회지
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• 제11권1호
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• pp.1-12
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• 2023

Purpose : This study examined the relationship between oral health management behavior and subjective health perception by using a tool that measures health-related quality of life named EQ-5D. The findings are expected to provide fundamental data for developing diverse programs, including health- and oral-health-related educational media, to ultimately enhance people's health-related quality of life. Methods : Adults over the age of 20 were extracted from the raw materials of the 8th national health and nutrition examination survey conducted in 2019. Among them, 4034 were finally chosen as the study subjects after checking the response distribution of relevant questions and excluding inadequate samples. Variables included general characteristics, health management behavior, oral health management behavior, subjective health perception, and EQ-5D level. Cross-tabulation test, independent t-test, one-way analysis of variance, and linear regression analysis were conducted using SPSS 25.0. Results : EQ-5D, which measures the level of health-related quality of life, was high when the subjects had a medical check-up experience, no experience of unsatisfactory medical service, and did not get an influenza vaccination (p<.001). The quality of life was higher when the subjects received dental inspections, did not require treatment, and used oral care goods (p<.005). Health-related quality of life was also higher when the subjective health level and subjective oral health level were high. Conclusion : Results indicate that subjective health, oral health perception level, and quality of life together were high when people had a regular check-up, did not neglect treatment, and used oral care goods. Considering the findings of this study, check-up programs that are customized for each age group are necessary. Health-related quality of life could be enhanced through the provision of diverse medical services and active efforts to prevent any medical blind spot.

• 치위생과학회지
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• 제5권4호
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• pp.171-177
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• 2005

본 연구는 어머니의 사회경제적 특성과 어머니의 구강보건지식 및 행동이 치과의료이용경험과 이용목적에 미치는 영향을 분석하고자 서울특별시에 소재한 2개의 어린이집에 내원하는 만 5-6세 유아를 자녀로 둔 103명의 어머니를 대상으로 설문조사를 실시하여 분석한 결과, 다음과 같은 결과를 얻었다. 1. 어머니의 이용목적에 따른 치과의료이용경험율은 치료(56.7%), 정기검진(23.3%), 예방(20.0%)순으로 나타났다. 2. 어머니의 사회경제적 특성 및 구강보건지식과 치과의료이용경험과의 상관성은 유의한 차이가 없었으나, 어머니의 구강보건행동과의 상관성은 치실 사용율이 낮을수록 치과의료이용경험율이 높게 나타났다(p < 0.01). 3. 어머니의 사회경제적 특성과 치과의료이용목적과의 상관성은 연령별 33-35세군(71.4%)에서, 학력별 대졸군(57.1%)에서 정기검진목적 치과의료이용경험율이 높게 나타났다(p < 0.05). 4. 어머니의 구강보건행동과 치과의료이용목적과의 상관성은 치실사용율이 높을수록 정기검진목적 치과의료이용경험율이 높게 나타났고(p < 0.001), 불소함유치약 사용율이 높을수록 치료목적 치과의료이용경험율이 높게 나타났다(p < 0.05). 5. 치과의료이용경험을 종속변수로 한 다중회귀분석 결과는 설명변량 65%로, 월평균소득(250만원 이하)이 유의미한 설명요인으로 나타났으며, 치과의료이용목적을 종속변수로 한 다중회귀분석에서는 정기검진의 경우 설명변량은 70%이였으며, 직업(전문직), 연령(33-35세)이 유의미한 설명요인으로 나타났고, 예방목적의 경우 설명변량은 78%이였으며, 연령(33-35세), 월평균소득(250만원 이하)이 유의미한 설명요인으로 나타났으며, 치료목적의 경우는 설명변량 33%이였으며, 연령(32세 이하)이 유의미한 설명요인으로 나타났다.

• 한방안이비인후피부과학회지
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• 제19권3호통권31호
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• pp.134-145
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• 2006

Objective : This study was carried out to investigate what type of assumption and conditions are needed for the application of various statistical techniques such as descriptive statistics, t-test, analysis of variance, correlation analysis, regression analysis and chi-square test and to evaluate that they are used correctly in the research process. Methods : One more methods of statistical analysis were used in 91 papers among 162 papers selected from the journal of Korean oriental medical Ophthalmology & Otolaryngology & Dermatology from April 2003 to December 2005. So we analysed the type of statistical analysis method in 91 papers(clinical and experimental study) and assessed the their validity of statistical techniques by the check list consisting of 34 items(3 items for validity assessment of descriptive statistics, 6 items for t-test, 7 items for analysis of variance, correlation analysis and regression analysis, respectively, 4 items for chi-square test) Results : 1. The type of 65(40%) cases is experimental trial, the type of 55(34%) cases is case report, the type of 26(16%) cases is clinical trial and the type of 16(10%) cases is review, in 91 papers using statistical techniques among 162 papers selected from the journal of Korean oriental medical Ophthalmology & Otolaryngology & Dermatol-ogy from April 2003 to December 2005. 2. One more methods of statistical analysis were used in the experimental and clinical study. When we classified 125 units using statistical analysis methods in 91 papers according to statistical techniques such as descriptive statistics, t-test, analysis of variance, correlation analysis, regression analysis and chi-square test, the number of independent sample t-test is 33(26%), the number of only descriptive statistics is 28(22%), the number of independent sample t-test is 33(26%), the number of only descriptive statistics is 28(22%), the number of one way ANOVA is 15(12%), the number of non-parametric test 10(8%). 3. After carrying out one way ANOVA, the number of using multiple comparison methods is 15(Scheffe:6(26%), Duncan:4(17%), Dunnett:3(13%), Tukey:2(9%)) out of 23 (total case carrying out one way ANOVA). 8(35%) out of 23 did not enforce multiple comparison methods after carrying out one way ANOVA. 4. From the assessment of validity about 63 cases using statistical techniques(except descriptive statistics), 5(8%) cases are proper, the other 58(92%) are improper, so we recognized a serious misuse of statistical application in our journal. 5. The number of case below 10 sample size in experimental and clinical study(except descriptive statistics) is 31(34%) and frequent. Also the number of case containing no mention of sample size is 41(45%, including culture study). 6. For example of statistical error, there are wrong choice of statistical technique, lack of check on standard assumption(such as standard distribution, equivariance, independence), and so on. Conclusions : We investigated the validity of statistical analysis methods in our journal by check list consisting of 34 items and suggested correct statistical analysis methods. We should practice the spread of education about statistical analysis methods and precis application, enhance objectivity and reliability of our thesis and further correspond with purpose of scientific study.