• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.222-229
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• 2006

Three dimensional turbulent flow in the scroll volute of centrifugal compressor has been numerically investigated in this paper by solving the Navier-Stokes equations and $\kappa-\varepsilon$ equation model. The computational grid for the flow field of the scroll volute has been constructed based on the multi-block grid concept, which is good to avoid the central grid singularity as well as to promote grid stretching toward the volute wall. Numerical result has been obtained for both the two- and three- dimensions. For the latter flow, result of the scroll volute flow is compared with that of the straight conical volute. This comparison has sorted out the characteristic features of the three-dimensional scroll-type volute flow of centrifugal compressor.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.23 no.3
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• pp.253-266
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• 2019

In this article, a systematic solution based on the sequence of expansion method is planned to solve the time-fractional diffusion equation, time-fractional telegraphic equation and time-fractional wave equation in three dimensions using a current and valid approximate method, namely the ADM, VIM, and the NIM subject to the estimate initial condition. By using these three methods it is likely to find the exact solutions or a nearby approximate solution of fractional partial differential equations. The exactness, efficiency, and convergence of the method are demonstrated through the three numerical examples.

• Journal of Distribution Science
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• v.13 no.2
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• pp.85-94
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• 2015

Purpose - This study attempts to examine the impacts of consumers' perceived service convenience of retailers on various service performance metrics such as service quality and customer satisfaction. It also tries to investigate differences in the importance of service convenience dimensions on service performance between a department store and a general super market. Research design, data, and methodology - The four hypotheses in this study were proposed and tested. Two hypotheses were on the causal relationships between service convenience dimensions and service performances (service quality and customer satisfaction). The other two hypotheses were on comparisons for the effects of convenience dimensions on service quality and customer satisfaction between department stores and general super markets. To test the hypotheses, three department store chains (Hyundai, Lotte, and Shinsegae department Store) and three general super markets (E-mart, Homeplus, and Lotte mart) were involved. Overall, 510 usable responses were used. The data were analyzed using regression analysis. Results - The results largely support the hypothesized relationships of the proposed model. The results show that access convenience, transaction convenience, benefit convenience, and post-benefit convenience have positive influences on service quality, whereas decision convenience, access convenience, transaction convenience, benefit convenience, and post-benefit convenience have positive effects on customer satisfaction. Furthermore, the results show that there are differences between department stores and general super markets in the effects of benefit convenience and post-benefit convenience on service quality as well as the effects of transaction convenience and post-benefit convenience on customer satisfaction. Conclusions - The concept of service convenience is important in retail environments but little is known about this topic in retail literature. Specially, while service convenience dimensions have different impacts on service performance in distinct retail environments, there has been little investigation or comparison between retail types as regards service convenience. This study is the first to test the differences between distinct retail types (department stores and general super markets) on the service convenience-service performance links. Managerially, the findings of this study suggest that the service convenience management of retailers is an important part of successful service performance management. Because it is most important that both department stores and general super markets enhance benefit convenience to improve service performance, managers of both store types need to invest their resources to reduce consumers' perceived time and effort expenditures to experience the retailer's core benefits. Therefore, the results of this study suggest that retail stores should spend human and financial resources to enhance customer perceptions of service convenience, while also considering what constitutes the service outcome in the consumer's mind. Furthermore, the findings suggest that managers need to use different service convenience management tactics in department stores and general super markets. Specifically, managers in general super markets should pay more attention to benefit convenience and transaction convenience to achieve better service performance whereas managers in department stores should concentrate on post-benefit convenience to create customers' positive evaluation.

• The korean journal of orthodontics
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• v.41 no.4
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• pp.288-296
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• 2011

Objective: The purposes of this study were to evaluate the relationship between the dental and basal arch forms; to analyze their differences in the tapered, ovoid, and square arch forms in normal occlusion by using three-dimensional (3D) virtual models; and to test the hypothesis that the overjet and maxillomandibular basal arch width difference have a significantly positive correlation. Methods: Seventy-seven normal occlusion plaster casts were examined by 3D scanning. Facial axis (FA) and WALA points were digitized using the Rapidform 2006 software. The dimensions of the dental and basal arches and the overjet were measured. The samples were classified into 3 groups according to arch forms: tapered (n = 20), ovoid (n = 20), and square (n = 37). Analysis of variance (ANOVA) was used to compare the dental and basal arch dimensions. The Pearson correlation coefficients between the intercanine as well as the intermolar widths at the FA and WALA points were calculated. Results: With regard to the basal arch dimensions, the tapered arch form showed a larger mandibular intermolar depth than the ovoid. Strong correlations were noted between the basal and dental intermolar widths in both the upper and lower arches (r = 0.83 and 0.85, respectively). Moderate correlation was found between the upper and lower intercanine widths (r = 0.65 and 0.48, respectively). Conclusions: The 3 dental arch form groups differed only in some dimensions of the skeletal arch. Moderate correlations were found between the basal and dental intercanine widths. These findings suggest that the basal arch may not be a principle factor in determining the dental arch form.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.145-155
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• 2020

Since Campbell (1990) proposed multidimensionality of job performance, unlike the single structure of traditional job performance, it has been largely classified as task performance, contextual performance, and counterproductive work behavior. The objective of this study is to validate the threecriteria currently considered major aspects of job performance, to identify different types of performance based on three dimensions, and to compare the power of personality factors among performance types. A total of 681 employees working at various organizations participated in an on-line survey. The survey included boththe exploratory and confirmatory factor analyses. A 3-factor job performance model consisting of three dimensions was also included. The relationships between performance dimensions and personality factors differedby dimensions of performance, supporting the validity of the 3-factor structure of performance.The results of the Latent Profile Analysis identified four types of performance: exemplary, moderately conscientious moderate, and conscientious, butlow.. The Multinomial logistic regression analysis showed each type differed significantly according to the predictors of personality variables. In conclusion, implications and limitations of the study were noted.

• Journal of Distribution Science
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• v.13 no.8
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• pp.91-96
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• 2015

Purpose - This study reviews the delivery of child welfare service quality and examines how the dimensions of the variables of customer satisfaction impact the results from a service distribution perspective. This study differs from existing research since it proposes that a recognized level of child welfare service quality is necessary to achieve customer satisfaction from the perspective of service distribution. Research design, data, and methodology - This study explores child welfare service quality factors that affect customer satisfaction. The study examines and analyzes demographic variables, service quality dimensions, and the causal relationships between child welfare service quality and customer satisfaction. Data from 300 child welfare cases were collected from organizations in Korea in the areas of Busan and Gyeongsangnamdo. The methods of analysis are as follow. First, using descriptive analysis frequency, the percentages were evaluated to assess the demographic variables. Second, Cronbach's α was used to test reliability and to evaluate the internal consistency of the measuring of items. Third, multiple regression analysis was conducted to find out how much the independent variable can affect customer satisfaction. Results - Five factors of child welfare service quality were identified in three categories: process quality (assurance, empathy), results quality (reliability, caring), and physical environment quality (tangibles). There were significant differences among the effects of the child welfare service quality factors on customer satisfaction. A multiple regression analysis was done with process quality (assurance, empathy), results quality (reliability, caring) and physical environment quality (tangibles) to test the hypothesis: assurance (t=2.434, p<0.05), empathy (t=3.677, p<0.001), reliability (t=3.271, p<0.05), caring (t=4.380, p<0.000), and tangibles (t=3.654, p<0.01) had a positive influence on child welfare service quality from a service distribution perspective. Therefore, hypotheses 1, 2, 3, 4, and 5 were supported. In addition, multiple regression analysis on the effects of the variables showed that caring (β=0.273), empathy (β=0.246), tangibles (β=0.265), reliability (β=0.152), and assurance (β=0.131) all had a positive and strong influence on child welfare service quality from a service distribution perspective. Therefore, all child welfare service quality categories (process, results and physical environment quality) were positively statistically significant. Conclusion - In this study, the main findings can be summarized as follows. First, the quality of service of child welfare consists of three dimensions of quality: process quality, results quality, and physical environment quality. The results of the multiple regression analysis also showed that caring and reliability were confirmed as more meaningful variables by the increasing loading factors. Second, the family members involved in child welfare proposed caring as the most important variable among the dimensions of service quality. Third, the results of the hypothesis testing using regression showed that all child welfare service quality factors had a positive impact on customer satisfaction. The results of the study could provide useful information to help increase the effectiveness of delivery strategies for child welfare service quality from a service distribution perspective.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.358-365
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• 2019

This study was conducted to estimate the dimensions of horticultural products and the mean plant height of plug seedlings using three-dimensional (3D) images. Two types of camera, a ToF camera and a stereo-vision camera, were used to acquire 3D images for horticultural products and plug seedlings. The errors calculated from the ToF images for dimensions of horticultural products and mean height of plug seedlings were lower than those predicted from stereo-vision images. A new indicator was defined for determining the mean plant height of plug seedlings. Except for watermelon with tap, the errors of circumference and height of horticultural products were 0.0-3.0% and 0.0-4.7%, respectively. Also, the error of mean plant height for plug seedlings was 0.0-5.5%. The results revealed that 3D images can be utilized to estimate accurately the dimensions of horticultural products and the plant height of plug seedlings. Moreover, our method is potentially applicable for segmenting objects and for removing outliers from the point cloud data based on the 3D images of horticultural crops.

• Journal of the Korean Society for information Management
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• v.23 no.1 s.59
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• pp.243-259
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• 2006

This paper examines the values of various library functions according to users' points of view. To execute this study, the several 'circumstance', related variables and 'condition' variables that lead to factors or functions of academic libraries were measured. Analysis was carried out in three stages. In the first, factor analysis was used on the three multi variable dimensions to ensure that the groups of variables loaded significantly and uniquely on the respective dimensions. The second phase of analysis involved the use of binary logistic regression analysis to complete research models. In the third phase, t-test was used to identify significant differences in the independent variables for additional explanation of the models. Books, competition & effectiveness and fee verses free (fee-free hereafter) are the three main factors that distinguish not only the purpose of using an academic library but also the degree of influence on knowledge, information and library facilities for the users. In addition, the fee-free factor related to digital library facilities was also uncovered.

• International Journal of Concrete Structures and Materials
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• v.8 no.1
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• pp.83-97
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• 2014

This paper presents the results of an investigation aimed at developing reinforced concrete beams consisting of precast permanent U-shaped reinforced mortar forms filled with different types of core materials to be used as a viable alternative to the conventional reinforced concrete beam. To accomplish this objective, an experimental program was conducted and theoretical model was adopted. The experimental program comprised casting and testing of thirty beams of total dimensions $300{\times}150{\times}2,000mm$ consisting of permanent precast U-shaped reinforced mortar forms of thickness 25 mm filled with the core material. Three additional typical reinforced concrete beams of the same total dimensions were also cast to serve as control specimens. Two types of single-layer and double-layers steel meshes were used to reinforce the permanent U-shaped forms; namely welded wire mesh and X8 expanded steel mesh. Three types of core materials were investigated: conventional concrete, autoclaved aerated lightweight concrete brick, and recycled concrete. Two types of shear connections between the precast permanent reinforced mortar form and the core material were investigated namely; adhesive bonding layer between the two surfaces, and mechanical shear connectors. The test specimens were tested as simple beams under three-point loadings on a span of 1,800 mm. The behavior of the beams incorporating the permanent forms was compared to that of the control beams. The experimental results showed that better crack resistance, high serviceability and ultimate loads, and good energy absorption could be achieved by using the proposed beams which verifies the validity of using the proposed system. The theoretical results compared well with the experimental ones.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.172-185
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• 2020

To explore the impact of restaurant service quality for foreigners in South Korea on customer satisfaction, customer trust, and loyalty from three dimensions: quality of physical environment, food quality, and service quality and the influence of perceived price on satisfaction and loyalty, a survey was conducted by collecting 202 valid questionnaires and Amos 23 was used to examine the relationships between variables. The results show that the quality of physical environment, food quality, and service quality have significant positive effects on customer trust, but only food quality has a significant effect on customer loyalty and all three have no significant effects on customer satisfaction. In addition, customer trust has a significant positive effect on customer satisfaction and customer loyalty, but the effect of customer satisfaction on loyalty has not been verified in this study. At the same time, perceived price has a significant positive effect on customer satisfaction, but no significant effect on customer loyalty. Then the study examined the moderating effect of gender by using the SEM multi-group analysis method, founding that there are no significant differences between male and female on the impact of the three dimensions of restaurant service quality on customer satisfaction, and no significant differences between male and female on the impact of perceived price on customer satisfaction and customer satisfaction on loyalty, meaning that gender's moderating effects are not valid. These conclusions of this study are useful for restaurant operators to improve the quality of the physical environment, food quality and service quality, effectively improve customer trust, and thus customer satisfaction and loyalty.