• Journal of Advanced Navigation Technology
• /
• v.18 no.4
• /
• pp.304-311
• /
• 2014

In this paper, we propose a ultra sound inspection technique for automatic defect detection and classification in aircraft composite materials. Using local maximum values of ultra sound wave, we choose peak values for defect detection. Distance data among peak values are used to construct histogram and to determine surface and back-wall echo from the floor of composite materials. C-scan image is then composed through this method. A threshold value is determined by average and variance of the peak values, and defects are detected by the values. PCA(principal component analysis) and QDA(quadratic discriminant analysis) are carried out to classify the types of defects. In PCA, 512 dimensional data are converted into 30 PCs(Principal Components), which is 99% of total variances. Computational cost and misclassification rate are reduced by limiting the number of PCs. A decision boundary equation is obtained by QDA, and defects are classified by the equation. Experimental result shows that our proposed method is able to detect and classify the defects automatically.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.570-578
• /
• 2016

This study examined the relationship between the attitudes toward pets and elementary school students' empathy ability, and analysed the difference in the attitude toward pets and the level of elementary school students' empathy depending on gender, school year and rearing period. To carry out this study, data were collected by giving a test on the attitudes toward pets and a test in empathy ability to 220 elementary school students in Daejeon Metropolitan City, who had a pet rearing experience in the past. With regard to the data collected, correlation analysis, multiple regression analysis, t-test and analysis of variance were carried out using SPSS win23. As a result of the analysis, the following facts were revealed. First, the attitudes and the degree of empathy ability for pets showed relevance. Second, affection for pets, interaction, and the joy of having pets were closely related to the empathy ability. Third, there was a significant difference in the attitude toward pets depending on gender and rearing period. Finally, there was a significant difference in empathy ability depending on the gender and rearing period. However, there was no significant difference depending on the school year.

• Journal of Korean Society for Geospatial Information Science
• /
• v.18 no.2
• /
• pp.13-20
• /
• 2010

Currently, NGII(National Geographic Information Institute) provides VRS(Virtual Reference System) service using 44 CORS(Continuously Operating Reference Stations). Since the VRS provides high-precision coordinate in a short time, the users and applications are expected to be rapidly increasing. The accuracy analysis on the VRS service, however, was not sufficiently performed yet. Therefore, in this study, the VRS data is acquired from various circumstances and its accuracy is analyzed. According to analysis, it was concluded that the VRS could be applied to public control point survey. Furthermore, it was found that the PQ(Position Quality) which represents variance of estimated coordinates rather than GDOP(Geometric Dilution of Precision) is more relevant as a factor to determine the accuracy of coordinates. Based on the analysis of data from four manufacturers (TRIMBLE, MAGELLAN, LECIA, TOPCON), it was confirmed that the standard deviations better than 3cm. Therefore, VRS Survey apply to public control point survey.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.10
• /
• pp.179-186
• /
• 2023

This study investigated tooth whitening preferences among college students, evaluating their knowledge, satisfaction, aesthetic criteria, and preferences, while identifying influencing factors. Using a 28-item questionnaire covering general, tooth whitening knowledge, satisfaction, aesthetic criteria, and preference questions, 175 participants surveyed from June 7th to 10th, 2022, underwent analysis. Descriptive statistics, t-tests, analysis of variance, and regression analysis were applied. Results showed tooth whitening knowledge scored 2.90 out of 5 points, satisfaction 2.97, aesthetic criteria 3.59, and preferences 3.28. Tooth whitening knowledge was higher among female and health-related major students, while satisfaction was greater among males, non-health-related majors, and those without cosmetic procedures. Aesthetic criteria were stronger in participants with higher allowances and cosmetic procedures experience. No significant tooth whitening preference differences were found based on general characteristics. Regression analysis revealed significant impact of aesthetic criteria on tooth whitening preferences (β=0.252).

• Journal of Digital Convergence
• /
• v.14 no.5
• /
• pp.519-526
• /
• 2016

This study aims to verify the relationship between achievement goal orientation and life satisfaction. It consists of 450 athletes from high school, university, and professional teams as an object. After examining reliability and validity on questionnaires, the data, based on gender, was evaluated by analysis of variance, correlation analysis, and multiple regression analysis. The result says that male athletes have higher scores in Mastery approach and Performance approach - two of the four achievement motivation factors - which means a meaningful difference between gender. Life satisfaction also shows that male players have more satisfaction and indicates a big difference between gender. Finally, according to the multiple regression analysis on the Athlete's achievement goal orientation and life satisfaction, Mastery approach affects statically but Mastery avoidance does negatively on athlete's life satisfaction. The gender-based relationship between Athlete's achievement goal orientation and life satisfaction reveals that mastery approach gives positive effects on life satisfaction for both genders, but mastery avoidance influences negatively on male and female life satisfaction.

• Journal of the Korean Society for information Management
• /
• v.26 no.4
• /
• pp.169-186
• /
• 2009

This paper examined what factors affect the immediacy index showing the average number of times an article is cited in the year it is published. Not only Seventy-one immediacy indexes for subject field biology on JCR 2008 edition were gathered, but also many characteristics of scholarly journals that may influence the indexes directly or indirectly were aggregated. Simple correlation coefficient analysis, factor analysis, and regression analysis were performed on the paper. Therefore factors such as physical volume, availability, forthcoming issue, age and language explaining 67.64% of total variance were identified. After regression analysis using these factors as independent variables, the results were statistically significant. The results showed physical volumes, the total pages of publication, have an influence upon immediacy indexes obviously, although it is expected that journal reputations may affect immediacy indexes. Generally open access journals had high immediacy indexes. High ranked journals on immediacy index were apt to be issued frequently, uploaded very often on PMC, and published in major countries including United States and United Kingdom.

• Journal of the Korean Society for Library and Information Science
• /
• v.56 no.3
• /
• pp.47-72
• /
• 2022

This study aims to understand the trends of subjects related to real estate policies and public's emotional opinion on the policies. Two keywords related to real estate policies such as "real estate policy" and "real estate measure" were used to collect tweets created from February 25, 2008 to August 31, 2021. A total of 91,740 tweets were collected and we applied sentiment analysis and dynamic topic modeling to the final preprocessed and categorized data of 18,925 tweets. Sentiment analysis and dynamic topic model analysis were conducted for a total of 18,925 posts after preprocessing data and categorizing them into supply, real estate tax, interest rate, and population variance. Keywords of each category are as follows: the supply categories (rental housing, greenbelt, newlyweds, homeless, supply, reconstruction, sale), real estate tax categories (comprehensive real estate tax, acquisition tax, holding tax, multiple homeowners, speculation), interest rate categories (interest rate), and population variance categories (Sejong, new city). The results of the sentiment analysis showed that one person posted on average one or two positive tweets whereas in the case of negative and neutral tweets, one person posted two or three. In addition, we found that part of people have both positive as well as negative and neutral opinions towards real estate policies. As the results of dynamic topic modeling analysis, negative reactions to real estate speculative forces and unearned income were identified as major negative topics and as for positive topics, expectation on increasing supply of housing and benefits for homeless people who purchase houses were identified. Unlike previous studies, which focused on changes and evaluations of specific real estate policies, this study has academic significance in that it collected posts from Twitter, one of the social media platforms, used emotional analysis, dynamic topic modeling analysis, and identified potential topics and trends of real estate policy over time. The results of the study can help create new policies that take public opinion on real estate policies into consideration.

• Journal of Distribution Science
• /
• v.13 no.9
• /
• pp.103-112
• /
• 2015

Purpose - This paper aims to provide a step-by-step approach to factor analytic procedures, such as principal component analysis (PCA) and exploratory factor analysis (EFA), and to offer a guideline for factor analysis. Authors have argued that the results of PCA and EFA are substantially similar. Additionally, they assert that PCA is a more appropriate technique for factor analysis because PCA produces easily interpreted results that are likely to be the basis of better decisions. For these reasons, many researchers have used PCA as a technique instead of EFA. However, these techniques are clearly different. PCA should be used for data reduction. On the other hand, EFA has been tailored to identify any underlying factor structure, a set of measured variables that cause the manifest variables to covary. Thus, it is needed for a guideline and for procedures to use in factor analysis. To date, however, these two techniques have been indiscriminately misused. Research design, data, and methodology - This research conducted a literature review. For this, we summarized the meaningful and consistent arguments and drew up guidelines and suggested procedures for rigorous EFA. Results - PCA can be used instead of common factor analysis when all measured variables have high communality. However, common factor analysis is recommended for EFA. First, researchers should evaluate the sample size and check for sampling adequacy before conducting factor analysis. If these conditions are not satisfied, then the next steps cannot be followed. Sample size must be at least 100 with communality above 0.5 and a minimum subject to item ratio of at least 5:1, with a minimum of five items in EFA. Next, Bartlett's sphericity test and the Kaiser-Mayer-Olkin (KMO) measure should be assessed for sampling adequacy. The chi-square value for Bartlett's test should be significant. In addition, a KMO of more than 0.8 is recommended. The next step is to conduct a factor analysis. The analysis is composed of three stages. The first stage determines a rotation technique. Generally, ML or PAF will suggest to researchers the best results. Selection of one of the two techniques heavily hinges on data normality. ML requires normally distributed data; on the other hand, PAF does not. The second step is associated with determining the number of factors to retain in the EFA. The best way to determine the number of factors to retain is to apply three methods including eigenvalues greater than 1.0, the scree plot test, and the variance extracted. The last step is to select one of two rotation methods: orthogonal or oblique. If the research suggests some variables that are correlated to each other, then the oblique method should be selected for factor rotation because the method assumes all factors are correlated in the research. If not, the orthogonal method is possible for factor rotation. Conclusions - Recommendations are offered for the best factor analytic practice for empirical research.

• Culinary science and hospitality research
• /
• v.21 no.6
• /
• pp.49-62
• /
• 2015

Give that statistical analysis is an essential component of foodservice-related research, the purpose of this review is to analyse research trends of statistical methods applied to foodservice-related research. To achieve these objective, this study carried out a content analysis on a total of 251 out of 415 research articles published in The Korean Journal of Culinary Research(TKJCR) from January 2010 to December 2013. Of the total 164 research articles focussing on natural science research, qualitative research, articles written in English were excluded from the scope of this study. The results of this study are as follows. First, it turned out that 269 research articles applied quantitative research methods, and only 10 articles applied qualitative research methods among the 279 research articles based on social science research methods. Second, 20 article (8.0%) among the 251 did not specify the statistical methods or computer programs that were used for statistical analysis. Third, it was found that 228 articles (90.8%) used the SPSS program for data analysis. Fourth, in terms of frequency of use, it was revealed frequency analysis was most used, followed in order by reliability analysis, exploratory factor analysis, correlation analysis, regression analysis, structural equation modeling, confirmatory factor analysis, t-test, variance analysis, and cross tabs analysis, However, 3 out of 56 research articles that used a t-test did not suggest a t-value. 10 out of 64 articles that used ANOVA and demonstrated a significant difference in between-group mean did not conducted post-hoc test. Therefore, the researchers with interest in foodservice fields need to keep in mind that choosing and applying the correct statistical technique both determine the value and the success or failure of a study. To enhance the value and success of a study, it is necessary to use the proper statistical technique in an efficient way in order to prevent statistical errors.

• Culinary science and hospitality research
• /
• v.20 no.1
• /
• pp.189-204
• /
• 2014

This study is aimed to identify the relationship between Korean restaurant selection attributes and behavioral intention regarding foodservice consumption tendency. In order to achieve the purpose of research, frequency analysis, factor and reliability analysis, correlation analysis, cluster analysis, chi-square test, variance analysis, and multiple regression analysis were conducted using SPSS 18.0. As a result of variance analysis, accessibility did not appear to have a significant difference in all clusters, food quality appeared to have a significant result (F=5.587, $p{\leq}.001$), employees' service appeared to have a significant difference (F=5.186, p<.01), and price discounts also showed a significant difference (F=4.921, p<.01). Therefore, the first hypothesis that the foodservice consumption tendency has a difference in the Korean restaurants selection attributes was partially selected. In order to verify the hypothesis that the Korean restaurants selection attributes affect behavioral intention, the sub-factors of the Korean restaurant selection attributes (accessibility of restaurants, food quality, employees' service, price discounts) were set as independent variables, and the behavioral intention of foodservice consumers was set as a dependent variable. As a result, the accessibility of restaurants (${\beta}=.092$) and price discounts (${\beta}=.299$) have a non-significant effect on behavioral intention. However, a significant result was shown in food quality (${\beta}=.379$, p<.001) and employees' service (${\beta}=.251$, p<.001). Thus, the hypothesis that the Korean restaurant selection attributes have a positive effect on behavioral intention was partially selected. Based on the results, foodservice managers need to build up strategic management to improve food quality with better ingredients, sanitation, adequate quantity, and consistent taste of food. In addition, they should provide better service with well-trained employees.