• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.251-258
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• 2009

In this study, the optimum design conditions for embankment construction on soft clay layer improved by soil compaction pile (SCP) are discussed by comparing the practical design method to the reliability design which is based on the loss function and advanced first order second moment (AFOSM) method. The results are summarized as follows; 1) the relationship between safety factor and failure probability becomes heavy exponentially, failure probability decreases rapidly till 1% approximately until safety factor is smaller than 1.2 and after then, failure probability decrease gradually along the increase of the safety factor. The design safety factor of 1.2 may be the critical value that has been established on considering both relationships appropriately, 2) the safety factor of 1.15 at the minimum expected total cost is a little smaller than the design safety factor of 1.2 and the failure probability is about 1%, 3) the sensitivities of the ratio of stress share and the internal friction angle of sand is larger than the variables related the undrained shear strength of soft layer. This result means that the distribution characteristic of n and ${\phi}$ influences on the stability analysis considerably and they should be considered necessarily on stability analysis of embankment on soft layer improved by SCP, 4) new failure points of the input variables at the design safety factor of 1.2(below failure probability of 0.1~0.3%) is far 1~2 times of standard deviation from the initial design values of themselves.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.609-615
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• 2010

Angular contact ball bearings in a high speed spindles are under the extreme conditions, such as high temperature, big centrifugal force and thrust cutting forces. So, the assembly contacts between spindle shaft and inner ring bearings, bearing housing and outer ring of bearings are occasionally unstable at high speed revolution. Furthermore, the ball contact angle of a bearing, which influence stiffness and lifetime of bearings, are changed according to loads and rotational speed. To analyze internal forces of a bearing under high speed revolution, the ball contact are calculated using nonlinear equations in consideration of rotational speed, thrust loads and raceway form. Diameter increase of inner and outer ring by influence factors, such as internal forces to inner and outer ring, centrifugal force and temperature of inner and outer rings are calculated to establish stable state in bearing assembly in high speed spindle. Finally, contribution ratio of influence factor to assembly design tolerance of inner and outer rings are shown and the stable assembly design tolerance are proposed.

• International Journal of Quality Innovation
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• v.2 no.2
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• pp.24-33
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• 2001

As we know, the quality of processes is technically depicted by variation, a product or process with the best quality must naturally require the variation as less as possible. The variation is usually reduced with many ways, say, by adjusting parameters settings under robust design with many turns expensive experiments. So ones are trying to reach the robustness by detecting cheap and simple methods. In this paper, a both practical and simple technique for quality improvement, namely reducing the variation, by data classification is studied. First, all possible system factors are included, which may dominate the variation law. And then we make use of the past observations and their classification as well as boxplot charts to find out the internal rule between the variation and the system factor. Next, adjust the location of the system factor according to the rule so that the variation could, to some extent, be lessened. Finally, two typical quality improvement cases based on data classification are presented.

• Korean Journal of Human Ecology
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• v.15 no.2
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• pp.251-259
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• 2006

The purpose of this study is to identify main effect of gender and expenditure, and interaction effect of gender by expenditure on satisfaction with foodservices of western restaurants. Accordingly, this study surveyed questionnaires concerning 20 measures of foodservice as well as major subject descriptors. The result of this study was as follows: KMO and Bartlett's test statistics showed that the data well fitted a factor analysis. Results of the factor analysis, average variance extracted estimates, and shared variance showed that the convergent and discriminant validities of 5 factors were supported, and Cronbach's alpha also showed that the internal consistencies of 5 factors were supported. But there was an interaction effect between independent variables and covariate on service quality factor. This study, therefore, used food decor factor, facility factor, food quality factor, and food value factor as dependent variables in two way 3$\times$2 design factorial ANCOVA. It was found that there were no main effects of gender and expenditure on those four factors. It was however revealed that there was an interaction effect of gender by expenditure on food decor factor.

• Journal of Korean Elementary Science Education
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• v.35 no.1
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• pp.123-135
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• 2016

Interest is one of the important factors in science education. The purpose of this study was to investigate factors affecting the follow-up interest of elementary school students on topics of 'Small Organisms' World'. The follow-up interests of the students on the topic were grouped into three categories; the developed-expanded-deepened (EDD), the simply expanded and maintained (SEM), and the stoped or decreased (SD) types. Each types had specific distinguishing features. Through the examination of students' responses and the in-depth interviews, the factors affecting on the follow-up interests of the students were analyzed. The factors were classified into two types of the external factor and the internal one. While the external factors were mainly related to the instructional materials used in science class and teaching methods, the internal factors were related to the desire for knowing, prior knowledge, students' experience and attitude toward the topics of science. In relation to the types of the follow-up interests, these factors were affected by different causes. The EDD type was most affected by internal factors, such as desire for knowing and prior knowledge. The SEM type was shown to be most affected by external factors, such as instructional materials. The SD type was mainly influenced by external factors, such as teaching methods. From the analysis of internal factors, it was revealed that the attitude and the prior knowledge about the topic are related with the follow-up interests. There was a positive relationship between the levels of science attitude and science knowledge. The students who had EDD type had a higher level of attitude and knowledge. However, there were some students who had higher level of scientific knowledge with SD type. The results of in-depth interviews showed that they were influenced by negative perceptions about science and stress on their grades. In conclusion, each follow-up interest type were caused by the external factors contained in the processes of the science class and the internal ones associated with the individual features and were influenced by the science class. So, the teacher should help the students be able to have the EDD type of follow-up interest which is persisted even after the completion of the science curriculum. For this, when the teachers design science curriculum and plan lesson, they should consider both internal and external factors significantly influencing the students' follow-up interests.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.312-318
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• 2013

PURPOSE. The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS. A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of ${\alpha}$=.05. RESULTS. The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 ${\mu}m/m$ at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION. Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.

• Journal of the Korean Home Economics Association
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• v.43 no.10 s.212
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• pp.1-23
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• 2005

This study proposes design factors for Korean style ecological apartment for application in Cheongju. Library and internal surveys were performed to summarize the concept of locality in housing and to determine the present condition of apartment estates which were introduced with design factors according to locality, traditionalism, or ecology, fold surveys were carried out at 10 apartment estates to investigate the present condition of management and residents's un. The interviewees were concierges and representative residents. The following design factors for Korean style ecological apartment to be applied in Cheongju were proposed; layout and building shape according to climate as natural environment, landscape factors according to cultural assets as human environment, adolescent spaces according to population as social environment, road plan according to 'Cheongju Garosu-Gil' civil environment.

• Archives of design research
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• v.16 no.3
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• pp.221-230
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• 2003

In product design, many designers incorporate psychological aspects to express the "fun" factor. If so, is it possible to apply the fun inducing mechanism utilized in psychology to product design and are there any problems in the application\ulcorner Psychology defines the sense of fun as the result of relief to a situation that causes a mental accumulation through the discovery of a due. The psychological extraction of fun inducing mechanism tends to lean too much to the cognitive aspect. Therefore, when dealing with product design, psychology's particular disposition is inadequate in explaining the important perceptive factor of fun. This study hypothesizes that perceptive aspect of should be induced along with the cognitive aspect in order to rationalize fun in product design. In order to understand the perception of fun, this study will introduce the amusement aspect within Kitsch products. Methods of developing a humorous form will be studied and these methods will be applicable to perceptive aspects. This paper hypothesizes that through the theoretical basis of internal characteristic of cognitive factors and external characteristic of perceptive factors, the mechanism of fun can be determined.etermined.

• Steel and Composite Structures
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• v.25 no.2
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• pp.209-216
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• 2017

In this paper, the analysis of the behavior of surface cracks in finite-thickness plates repaired with a Boron/Epoxy composite patch is investigated using three-dimensional finite element methods. The stress intensity factor at the crack-front was used as the fracture criteria. Using the Ansys Parametric Design Language (APDL), the stress intensities at the internal and external positions of repaired surface crack were compared. The effects of the mechanical and geometrical properties of the adhesive layer and the composite patch on the variation of the stress intensity factor at the crack-front were examined.

• Journal of computational fluids engineering
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• v.19 no.4
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• pp.14-19
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• 2014

This study conducts shape optimization of rib turbulator on the internal cooling passage that has triangular cross-section of high pressure turbine nozzle. During optimization, various types of rib turbulator including angled, V-shaped, A-shaped and angled rib with intersecting rib are considered. Each type of rib turbulator is parameterized with attack angle(s), rib height, spacing ratio and bending/intersecting location. For optimization, Design of Experiment (DOE) and Kriging surrogate model are used to utilize computational resource more efficiently and Genetic Algorithm (GA) is used to search the optimum points. As a result, Pareto front of each type of rib turbulator with friction factor that relates to pressure drop in cooling passage and spatially averaged Nusselt number that relates to heat transfer on the wall is drawn and optimum points on the Pareto front are suggested.