• Journal of the Korean Data and Information Science Society
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• v.20 no.2
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• pp.377-385
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• 2009

Twenty five female students in Seoul participated and were divided into two group in the experiment of weight loss effect of two treatments. Fourteen students(Treatment A group), randomly chosen from the students, had fed on diet foods and exercised over 8 weeks, and the remaining students(Treatment B group) had fed on diet foods only for the same periods. Weights of 25 students had been measured repeatedly four times at an interval of two weeks during 8 weeks, It resulted from mixed model analysis of repeated measurements data that separate Toeplitz pattern for each treatment group was selected as the optimal covariance pattern. Based upon the optimal covariance pattern model, the baseline effect and time effect were found to be highly significant, but the treatment-time interaction effect was found to be insignificant. Finally, the students with diet foods and exercises were more effective in losing weight than the students with only diet foods were.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.765-772
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• 2017

Objective: This study examines the genetic factors influencing the phenotypes (four economic traits:oleic acid [C18:1], monounsaturated fatty acids, carcass weight, and marbling score) of Hanwoo. Methods: To enhance the accuracy of the genetic analysis, the study proposes a new statistical model that excludes environmental factors. A statistically adjusted, analysis of covariance model of environmental and genetic factors was developed, and estimated environmental effects (covariate effects of age and effects of calving farms) were excluded from the model. Results: The accuracy was compared before and after adjustment. The accuracy of the best single nucleotide polymorphism (SNP) in C18:1 increased from 60.16% to 74.26%, and that of the two-factor interaction increased from 58.69% to 87.19%. Also, superior SNPs and SNP interactions were identified using the multifactor dimensionality reduction method in Table 1 to 4. Finally, high- and low-risk genotypes were compared based on their mean scores for each trait. Conclusion: The proposed method significantly improved the analysis accuracy and identified superior gene-gene interactions and genotypes for each of the four economic traits of Hanwoo.

• Journal of the Korean Society of Food Culture
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• v.19 no.5
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• pp.544-555
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• 2004

The purpose of this study is to highlight the importance of relationship marketing which has been developed as an alternative way of handling marketing in family restaurants. This study focused on the consumers' behavior - mainly their switching behavior and loyalty toward relationship marketing activities exercised by from family restaurants. 269 usable questionnaires were collected from customers patronizing three family style restaurants in Seoul. Several statistical methods were used including descriptive analysis, reliability test, covariance analysis, confirmatory factor analysis, and covariance structural analysis. The result drawn from empirical test proved that relationship marketing activities actually are the significant determinants of relationship quality and thus to the customers' behaviors toward the restaurants they patronize. Managerial implications can be drawn from the result findings that restaurant companies can identify the activities of relationship marketing to continue the long-term relationship with their customers. Also restaurant companies can use the activities of relationship marketing as differentiating strategies, and allocate their resources into the activities of relationship marketing.

• Industrial Engineering and Management Systems
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• v.15 no.3
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• pp.251-258
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• 2016

Companies have developed a keen interest in bolstering their CSR activities. Especially in Japan, CSR is strongly associated with social contribution and $m{\acute{e}}c{\acute{e}}nat$ activities. On the other hand, the primary purpose of companies is to provide their products and services to consumers and thereby return value to their shareholders through sales and profits. It is, however, difficult to estimate directly the relationship between CSR and sales/profits. This study focuses particularly on CSR activities related to environmental and consumer issues and community involvement and development. It is also analyzed the relationship between the degree of CSR empathy and product purchase motivation. For accomplishment the purpose, a questionnaire is designed that elicits the respondent's degree of purchase intention and empathy toward CSR activities supported through sales. The object industry for questionnaires is TV maker. For results of the questionnaire, a covariance structure analysis is conducted to understand potential relationships among CSR activities, sales, and disposable budget. Through this study, it is able to clear the relationship between CSR activities and sales/profits. It is one of the advice to future prospect, strategy and CSR concept for the companies.

• Asia pacific journal of information systems
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• v.21 no.3
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• pp.51-69
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• 2011

Security has been considered one of the most critical issues for managing IT resources in many organizations. Despite a growing interest and extensive research on security at various levels, little research has focused on the comparison of security knowledge levels between different cultures. The current study investigates and compares the security knowledge level between Korea and the U.S. Based on the literature review of spyware, Hofstede's cultural dimensions, and security knowledge, this study identifies three constructs (i.e., security familiarity, spyware awareness, and spyware knowledge) to examine the difference of security knowledge levels between Korea and the U.S. Six hundred ninety-six respondents from Korea and the U.S. participated in the survey, and an in-depth analysis based on analysis of covariance (ANCOVA) was carried out. The results show that the levels of security familiarity, spyware awareness, and spyware knowledge are significantly lower in Korea than in the U.S., as expected. These findings present a significant association between national culture and security knowledge, and the degree of individualism (or collectivism) plays an especially critical role in the perception of security. A number of implications for academia and practitioners emerge. Limitations and future research directions are discussed in the conclusion.

• Journal of Korean society of Dental Hygiene
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• v.23 no.2
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• pp.115-123
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• 2023

Objectives: This study was conducted to identify the oral hygiene status of children and adolescents from North Korean (NK) refugee families residing in South Korea (SK) and to find ways to improve it. Methods: This study examined 88 children in NK refugee families. Their oral hygiene ability were estimated using the Patient Hygiene Performance (PHP)-index for children. The Independent Samples t-test and one-way ANOVA were conducted on the oral hygiene status according to the characteristics of children of NK refugees, and covariance analysis was conducted by controlling for significant variables in the simple analysis. Statistical significance levels were set at than p<0.05. Results: The overall PHP-index of normal, poor, and severe poor were 14.8%, 5.7%, and 79.5%, respectively. Adjusted for sex, age, country of birth, duration of settlement, covariance analysis was performed to determine the PHP-index according to oral examination. PHP-index was 3.55±1.56 when the oral examination was conducted and 4.26±0.98 when the oral examination was not conducted; this difference was significantly (p=0.022). Conclusions: Children and from NK refugee families have severely poor oral hygiene. Therefore, education to improve the oral hygiene status is necessary.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.1
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• pp.29-43
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• 2024

The present study concerns a feasibility study for applying principal component analysis to ship dynamics in maneuver. Using the four degrees of freedom standard modular model for ship dynamics maneuver simulations of large angle zigzag tests with rudder deflection angle variations are conducted. The datasets of ship motion, hydrodynamic force, and moment during the maneuver are acquired to identify the principal modes. The covariance matrix of obtained ship dynamics variables shows a strong linear correlation between the motion, hydrodynamic force, and moment, except the surge force. Four eigenvectors of the covariance matrix are selected as the principal modes of ship dynamics. Using the principal modes, ship motion in turning circle and zigzag tests is reconstructed, showing good agreement with the original data.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1562-1573
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• 2024

This study rigorously examined uncertainty in the TMI-1 benchmark within the Uncertainty Analysis in Modeling (UAM) benchmark suite using the STREAM/RAST-K two-step method. It presents two pivotal advancements in computational techniques: (1) Development of an uncertainty quantification (UQ) module and a specialized library for the pin-based pointwise energy slowing-down method (PSM), and (2) Application of Principal Component Analysis (PCA) for UQ. To evaluate the new computational framework, we conducted verification tests using SCALE 6.2.2. Results demonstrated that STREAM's performance closely matched SCALE 6.2.2, with a negligible uncertainty discrepancy of ±0.0078% in TMI-1 pin cell calculations. To assess the reliability of the PSM covariance library, we performed verification tests, comparing calculations with Calvik's two-term rational approximation (EQ 2-term) covariance library. These calculations included both pin-based and fuel assembly (FA-wise) computations, encompassing hot zero-power and hot full-power operational conditions. The uncertainties calculated using both the EQ 2-term and PSM resonance treatments were consistent, showing a deviation within ±0.054%. Additionally, the data compression process yielded compression ratios of 88.210% and 92.926% for on-the-fly and data-saving approaches, respectively, in TMI fuel assembly calculations. In summary, this study provides a comprehensive explanation of the PCA process used for UQ calculations and offers valuable insights into the robustness and reliability of newly developed computational methods, supported by rigorous verification tests.

• Journal of Digital Contents Society
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• v.19 no.3
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• pp.489-496
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• 2018

This article is to examine the influence of occupational stress, socio-psychological factors and quality of sleep on fatigue symptoms from firefighters in fire service. The correlation coefficients were obtained by a tool of Pearson analysis, and covariance structure analysis was performed on the factors affecting the level of fatigue symptoms. This result suggests that the level of firefighters' fatigue symptoms in fire service. has a causal effect with occupational stress, socio-psychological factors and quality of sleep. Therefore, it is necessary to improve the work environment and to increase organizational support to deal with firefighters' fatigue in fire service.

• Journal of The Korean Association For Science Education
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• v.17 no.1
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• pp.1-10
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• 1997

The purpose of this study was to analyze the structural model of causal effects of students' variables on science process skills. Student characteristics investigated in the study included attitude related to the science, logical thinking ability, scientific experiences, cognitive style. Covariance structural modeling procedures were used to test causal inferences about hypothesized relationships. The sample consisted of 319 6th grade students and 321 8th grade students in Seoul City, Korea. Five instruments were used in the study, TSPS(test of science process skills), GALT(group assessment of logical thinking), CEFT(children embedded figures test), questionnaire of attitude related to the science, questionnaire of scientific experience. For statistical analysis, the study adopted the structural equation modeling with LlSREL, a computer statistical program developed by J reskog and S rbom. Major findings of the study are as follows:1) Logical thinking ability has a most strong direct effect on science process skills. 2) The structural coefficient of scientific experience influence on attitude related to the science has the greatest direct one than the others in the covariance structural model. According to the results of this study, it is very importance that various scientific experiences, particularly hands-on activity, should be offer to students to improve science process skills. Also, understanding the relationships of student variable to science process skills will be helpful to decision making on the part of curriculum developers, science teachers and researchers.