• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.543-551
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• 2011

Steam generator tubes for nuclear power plants contain the local shape transitions on their inner or outer surface such as dent, bulge, over-expansion, eccentricity, deflection, and so on by the application of physical force during the tube manufacturing and steam generator assembling and by the sludge (that is, corrosion products) produced during the plant operation. The structural integrity of tubes will be degraded by generating the corrosive crack at that location. The profilometry using the traditional bobbin probes which are currently applied for measuring the profile change of tubes gives us basic information such as axial locations and average magnitudes of deformations. However, the three-dimensional quantitative evaluation on circumferential locations, distributional angle, and size of deformations will have to be conducted to understand the effects of residual stresses increased by local deformations on corrosive cracking of tubes. Steam generator tubes of Korean standard nuclear power plants expanded within their tube-sheets by the explosive expansion method and suffered from corrosive cracks in the early stage of power operation. Thus, local deformations of steam generator tubes at the top of tube-sheet were measured with an advanced rotating probe and a laser profiling system for the two cases where the tubes expanded by the explosive expansion method and hydraulic expansion. Also, the trends of eccentricity, deflection, and over-expansion of tubes were evaluated. The advanced eddy current profilometry was confirmed to provide accurate information of local deformations compared with laser profilometry.

• Design & Manufacturing
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• v.11 no.1
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• pp.45-49
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• 2017

Currently, a lot of efforts to make increases the manufacturing efficiency have tried and there is growing the interest to implementing the machining operation through CAM automation and optimization. This kind of movement has shown gradually in 5X milling as well as 3X milling task. By the way, in case of 5X milling, it is difficult to hire the CAM experts who is an experience for 5X machining and also it has too big trouble to use them due to high cost. For this reason, you can see the manufacturer who is concern the CAM S/W to provide the NC automation program that beginners can generate easily the 5X milling in short term and the existing 5X milling process can be improved. These requirements need to make a NC automation process including the practical machining strategies same as the generation by NC expert. In order to support this, it is necessary to directly apply the 3D machining part based on NC template which includes the machining procedures, standard cutter library, auto machine area selection, analyze tool for part shape, machining condition setting considering the material stiffness to be provided by CimatronE and it should be created the 5axis machining data by a minimized operation. With user-friendly, CimatronE's NC machining automation tools improve the 5-axis machining process and speed up the process, maximizing work efficiency and improving product productivity compared to existing machining tasks.

• Advances in aircraft and spacecraft science
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• v.2 no.1
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• pp.95-108
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• 2015

Automatic Dependent Surveillance Broadcast (ADS-B) is quickly being adopted by aviation safety authorities around the world as the standard for aircraft tracking. The technology provides the opportunity for live tracking of aircraft positions within range of an ADS-B receiver stations. Currently these receiver stations are bound by land and local infrastructural constraints. As such there is little to no coverage over oceans and poles, over which many commercial flights routinely travel. A low cost space based ADS-B receiving system is proposed as a constellation of small satellites. The possibility for a link between aircraft and satellite is dependent primarily on proximity. Calculating the likelihood of a link between two moving targets when considering with the non-periodic and non-uniform nature of actual aircraft flight-paths is non-trivial. This analysis of the link likelihood and the performance of the tracking ability of the satellite constellation has been carried out by a direct simulation of satellites and aircraft. Parameters defining the constellation (satellite numbers, orbit size and shape, orbit configuration) were varied between reasonable limits. The recent MH370 disappearance was simulated and potential tracking and coverage was analysed using an example constellation. The trend of more satellites at a higher altitude inclined at 60 degrees was found to be the optimal solution.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.584-593
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• 2006

Statement of problem : Dental implant which has been developed gradually through many experiments and clinical applications is presently used to various dental prosthetic treatments. To conduct a successful function of implant prosthesis in oral cavity for a long time, it is important that not only structure materials must have the biocompatibility, but also the prosthesis must be designed for the stress, which is occurred in occlusion, to scatter adequately of load support. Therefore, it is essential to give the consideration about the stress analysis of supporting tissues for higher successful rates. Purpose : Recently, many implant manufacturing company produce various taper design of root form implant, the fixture is often selected. However, the stress analysis of taper form fixture still requires more studies. Material and method : This study we make the element models that five implant fixture; Branemark system(Nobel Biocare, Gothenberg, Sweden), Camlog system(Altatec, Germany), Astra system(Astra Tech, Sweden), 3i system(Implant Innovations Inc, USA), Avana system(Osstem, Korea) were placed in the area of mandibular first premolar and prosthesis fabricated, which we compared with stress distribution using the three-dimension finite element analysis under two loading condition. Results : This study compares the aspect of stress distribution of each system with the standard of Von mises stress, among many resulted from finite element analysis so that this research gets the following results. 1. In all implant system, oblique loading of maximum Von mises stress of implant, alveolar bone and crown is higher than vertical loading of those. 2. Regardless of loading conditions and type of system, cortical bone which contacts with implant fixture top area has high stress, and cancellous bone has a little stress. under the vertical loading, maximum Von mises stress is more higher in order of Branemark, Camlog, Astra, 3i, Avana. under the horizontal loading, maximum Von mises is more higher in order of Camlog, Branemark, Astra, 3i, Avana.

• Fashion & Textile Research Journal
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• v.14 no.3
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• pp.448-453
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• 2012

This study aims to categorize age groups for shoes manufacturing including shoes size and boot tree development for Koreans. In order to carry out the research, the characteristics of different parts of foot in relation to size are analyzed according to age and sex, making use of human body measurement database. As a result of statistical analysis, it was found that the measurement items such as foot length, metatarsal tibiale, foot breadth and instep circumference of a person reached the range of standard deviation and average numerical figures of an adult group (18-24) from the age of 14 in men's case, and from 12 for women's case, which indicates the time of completion of their foot growth. Based on these findings where males of 14 years old and females of 12 are within similar measurement range to adults, it is necessary to categorize the age groups for shoe sizing system into the following four groups: males 13 years old or under, males 14 years old or over, females 11 years or under, and females 12 years or over. The proportional measurement produced by dividing each measurement item of foot parts by foot length was compared in an independent samples t-test, and there were meaningful differences according to different foot shapes of the two age groups of males 13 or under - males 14 or over, and females 11 or under - females 12 or over. Also, the independent samples t-test for the age groups of males 13 or under - females 11 or under, and males 14 or over - female 12 or over, showed similar meaningful differences, which indicates the differences in foot shapes of male and female during the period of growth.

• The Research Journal of the Costume Culture
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• v.13 no.5 s.58
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• pp.671-685
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• 2005

The purpose of this study was to develop a new size range and size interval for early adolescent girls. For this purpose, a total of 529 girls aged between 10 and 14 were measured and data were collected from 42 anthropometric measurements and 41 photographic measurements per a person. SAS 8.1 was used in data analysis including means, standard deviations, and frequency analysis. The stature was divided at 5cm intervals as in KS into 9 sizes from the lowest 130cm to the highest 171cm. If waist circumference were divided at the same intervals, the sizes cannot reflect the body growth of adolescent girls at these ages. Thus this study set intervals between sizes irregularly based on the mean of waist circumference by the type of body shape. Based on the results, this study proposed: for Type A - 6 sizes (140A-58, 145A-54, 145A-62, 150A-58, 150A-62, 155A-62); for Type X- 9 sizes (150X-59, 155X-63, 155X-66, 160X-59, 160X-63, 160X-66, 165X-59, 165X-63, 165X-66): and for Type H - 7 sizes (145H-68, 150H-68, 150H-70, 155H-68, 155H-73, 160H-68, 160H-73). For the sizes selected for each type, reference measurements were decided - centering on items necessary for manufacturing clothes. Reference measurements suggested for lower garments 8 items including waist circumference, hip circumference, slacks length and crotch length. The suggested sizes are distributed in a wider range, so they are considered to be helpful for students to find clothes fitting their bodies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.245-252
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• 2016

In this study, an alternative bend design is proposed to overcome the aging problem in piping bends. In this design, the foam pad is not included. Finite element analysis was performed based on the total pipe diameter. From this analysis, the shape of the Shear Control Ring (SCR) was determined. Temperature, stress, and other data of the proposed reinforced pipe were acquired and analyzed after the test was performed. The value of the thermal stress for the reinforced steel pipe satisfied the required standard without the foam pad based on the manufacturing of the reinforced fitting and construction site of the test. The reinforcement provided a shear strength level for the foam pad that resulted in maximum shear stress less than stress based on the original foam pad applied at the pipe bend. Additionally, an increasing factor of safety effect for the reinforced fitting application was discovered.

• Journal of Fashion Business
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• v.4 no.1
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• pp.45-58
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• 2000

The purpose of this study is to provide for the basic data useful to the development of a quality bassiere featuring a good wearing feeling, to investigate the characteristics of breast shapes by age and suggest a brassiere sizing system for woman. For this purpose, the subjects of anthropometry were 220 women aged between 20 and 59. The anthropometric measurements were analyzed by various statistical methods mean, standard deviation, F-test, Duncan-test, Factor analysis, frequency. The results of this study can be summarized as follows; 1. According to the increase of age, the items of height were decreased and items of width, depth, circumference and length were increased, being obeser and breast point were drooped. So volume and bottom area of breast of 40 50's women were larger than 20 30's women and breast point width of 40 50's women was being wider by increase of the interior of breast. 2. From analyzing the effect of brassiere wearing, it was found that brassiere reformed the breast shape with the breast volume transferred from exterior part to interior part and the bottom area of breast diminished, so brassiere can have the breast location of adult woman up and the breast point width being centered 3. It was found that there was no direct linear relationships between under bust girth and cup size from analysis of breast measurements. Therefore those 2 factors(under bust girth and cup size) was brought into basic item of brassiere sizing system. From the dual distribution table whose intervals had been decided by KS K-0070(1999), it was picked out 12 sizes which had more than 4% of appearance for suggesting brassiere size chart. The sizing system covers 76.36% of all subjects and supply reference measurements relevant to brassiere manufacturing.

• Composites Research
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• v.19 no.3
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• pp.7-14
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• 2006

In this paper, an integrated probabilistic strength analysis was conducted to predict the reliability of a composite pressure vessel under inner pressure loading condition. As a probabilistic strength analysis, the probabilistic progressive failure model consisting of progressive failure model and Monte Carlo simulation was incorporated with a commercial FEA code, ABAQUS Standard, to perform the probabilistic failure analysis of composite structure which has a complex shape and boundary conditions. As design random variables, the laminar strengths of each direction were considered. Finally, from probabilistic strength analysis, the scattering of burst pressure could be explained and the reliability of composite pressure vessel could be obtained for each component. In case of composite structures in mass production, the effects of uncertainties in material and manufacturing on the performance of composite structures would apparently become larger. So, the probabilistic strength analysis is essential for the structural design of composite structures in mass production.

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.663-675
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• 2023

Purpose: Skewness is an indicator used to measure the asymmetry of data distribution. In the past, product quality was judged only by mean and variance, but in modern management and manufacturing environments, various factors and volatility must be considered. Therefore, skewness helps accurately understand the shape of data distribution and identify outliers or problems, and skewness can be utilized from this new perspective. Therefore, we would like to propose a statistical quality control method using skewness. Methods: In order to generate data with the same mean and variance but different skewness, data was generated using normal distribution and gamma distribution. Using Minitab 18, we created 20 sets of 1,000 random data of normal distribution and gamma distribution. Using this data, it was proven that the process state can be sensitively identified by using skewness. Results: As a result of the analysis of this study, if the skewness is within ± 0.2, there is no difference in judgment from management based on the probability of errors that can be made in the management state as discussed in quality control. However, if the skewness exceeds ±0.2, the control chart considering only the standard deviation determines that it is in control, but it can be seen that the data is out of control. Conclusion: By using skewness in process management, the ability to evaluate data quality is improved and the ability to detect abnormal signals is excellent. By using this, process improvement and process non-sub-stitutability issues can be quickly identified and improved.