• Journal of Aerospace System Engineering
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• v.15 no.2
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• pp.16-25
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• 2021

Reliability of fatigue strength on Aircraft Composites(GFRP) Structures was assessed in this paper. Fatigue strength of GFRP was used through the existing fatigue test data with Monte Carlo method. The S_a-N_f curve of composites fatigue strength was assumed as normal distribution and reliability was analyzed using SSIT model. Fatigue stress was designed IAW ASTM F3114-15 with special safety factor of S_sf=1.2~2.0. Reliability was calculated by analytic method and FORM. Sensitivity for the effect of mean and standard deviation of fatigue strength as well as fatigue stability was evaluated. This result can be usefully applied to reliability and fatigue design for composite structures of light weight aircraft.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.179-187
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• 2015

The purpose of this study is to identify the aspect that the traffic distribution function changes, according to the direction of the datum line and the horizontal and vertical positions of the datum point applied when it is calculated. Targeting routes at the entrance of Mokpo Harbor, this study tested using AIS survey data of January 2013 the effects of the three variables-direction of the datum line(${\theta}$), horizontal position($\mathfrak{L}_H$) and vertical position($\mathfrak{L}_V$) on mean ($\bar{x}$) and standard deviation (${\delta}$). The test result showed that $\bar{x}$ and ${\delta}$ were changed according to the change of ${\theta}$, because the extracted sample data were changed according to ${\theta}$; and the changes of $\bar{x}$ and ${\delta}$ according to ${\theta}$ were drawn as the relation of the sine function' sum. In addition, it was found that setting up ${\theta}$ that the change value of ${\delta}$ becomes the least as the direction of the datum line was valid, to determine the optimum passage distribution function on complex waters with multiple branches of route. The result of this study is expected to be used as basic data to understand maritime traffic flow based on more quantified data of normal distribution and make decisions related to maritime traffic safety management.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.81-95
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• 1994

This study was performed in a diatomite factory where silicosis had been found at October, 1993. The major objectives were to evaluate worker exposure to diatomaceous earth and to present engineering control methods for workplace management. Total and respirable dust of diatomaceous earth were measured. Size distribution of dust was analyzed by applying the multiple diffraction method. Also crystalline silica in respirable dust samples was analyzed qualitatively by X-ray diffraction. The suitable Local Exhaust Ventilation systems for that factory were recommended. The results were as follows. The airborne total and respirable dust concentrations by exposure groups showed approximate normal distribution. The means of total dust exposures at flour maufacturing, fire brick grinding and packaging, ceramic raws packaging processes exceeded Korean and ACGIH standards, $10mg/m^3$. The means of total and respirable dust concentrations to high exposure groups were 6.8 and 3.9 times higher than those of low expousre groups, respectively. The size distribution of diatomaceous earth dust was lognormal with a median diameter of $7.07{\mu}m$(range, $0.10-60.0{\mu}m$) and with a geometric standard deviation of 1.43. The crystalline silica in respirable dust samples was identified to quartz and cristobalite and/or tridymite. Above results suggest that engineering controls and periodic environmental and medical surveillances will be important for preventing silicosis in the diatomite factory.

• Journal of Distribution Science
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• v.20 no.8
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• pp.81-91
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• 2022

Purpose: The work aimed to integrate and distribute the knowledge of marketing and chemistry for product development, in which individual packaging from water hyacinth was ideal. Research design, data, and methodology: A customer perception was surveyed to guide the preparation process, and eco-packaging preparation followed the perception study. The satisfaction with the packaging using the 4Ps was determined. Results: 159 samples participated in the survey to establish their perceptions. They perceived that eco-packaging was a friendly environment with a score of 4.47. The uses of chemicals and water were less. The design for other functions than a normal function of packaging was preferred. The pulping was done using 3.0 M NaOH. The natural additives of carboxymethyl cellulose (defibering) and corn starch (adhesive) were desired. The paper was characterized according to The National Standard of Kraft paper and was equivalent to the liner board. The prototype of packaging was fabricated as individual packaging. The marketing mix was used to survey 200 samples. The satisfaction with the product was the maximum at 4.53, while the minimum was on price. The online channel was preferred to access the product. Conclusions: Water hyacinth could be added value as eco-packaging that the qualities of pulp were equal to the Kraft paper. Individual packaging from water hyacinth was satisfied.

• Clinical and Experimental Pediatrics
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• v.48 no.11
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• pp.1179-1186
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• 2005

Purpose : A universal standard of the birth weight for gestational age cannot be made since girth weight distribution varies with race and other sociodemographic factors. This report aims to establish the birth weight distribution curve by gestational age, specific for Korean live births. Methods : We used the national birth certificate data of all live births in Korea from January 2001 to December 2003; for live births with gestational ages 24 weeks to 44 weeks(n=1,509,763), we obtained mean birth weigh, standard deviation and 10th, 25th, 50th, 75th and 90th percentile values for each gestational age group by one week increment. Then, we investigated the birth weight distribution of each gestational age group by the normal Gaussian model. To establish final standard values of Korean birth weight distribution by gestational age, we used the finite mixture model to eliminate erroneous birth slights for respective gestational ages. Results : For gestational ages 28 weeks 32 weeks, birth weight distribution showed a biologically implausible skewed tail or bimodal distribution. Following correction of the erroneous distribution by using the finite mixture model, the constructed curve of birth weight distribution was compared to those of other studies. The Korean birth weight percentile values were generally lower than those for Norwegians and North Americans, particularly after 37 weeks of gestation. The Korean curve was similar to that of Lubchenco both 50th and 90th percentiles, but generally the Korean curve had higher 10th percentile values. Conclusion : This birth weight distribution curve by gestational age is based on the most recent and the national population data compared to previous studies in Korea. We hope that for Korean infants, this curve will help clinicians in defining and managing the large for gestational age infants and also for infants with intrauterine growth retardation.

• Fashion & Textile Research Journal
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• v.16 no.1
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• pp.118-127
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• 2014

This study proposed a revision of standard sizing system for infant clothing to provide exact information for consumers and manufacturers. The size designation was set up by compensating the defect of existing system. Basic body measurement and reference body measurement were analysed according to size designation. The ages of the infants ranged from 0 to 36 month in accordance with safety standard of KC Self-Regularity Safety Confirmation. The results are as follows: Size designation for infant clothing was based on height that was basic body measurement. Chest girth, waist girth, head girth, arm length, foot length and weight were also analysed according to age of the month. It was proposed that height could be written alone and height with age of month did together for size designation. Size intervals of basic and reference body measurements were fixed as follows: size intervals are 5 cm in height, 2 cm in chest girth, 2 cm in waist girth, 1 cm in head girth, 2 cm in arm length, 0.5 cm in foot length and 2 kg in weight. The distributions of height and chest girth showed normal distributions. As height was taller, chest girth was also bigger. But the distribution of waist girth didn't show remarkable change with age of month. The distributions of arm length and weight showed remarkable difference with growth in 0~9 months, but the amount of growth variation got less in 12~18 months.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.1
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• pp.19-26
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• 2004

According to increase of domestic blood components use, the quality control of blood components is necessary to support good products. The purpose of this study is used to provide the producing index of the good product as compared with the accuracy and validity for the distribution of the quality control data. The value of mean, standard deviation, 95% confidence interval and degree of normal distribution of data were calculated by univariate procedure, the value of monthly mean of each blood centers per items were compared by Analysis of Variance(ANOVA) test for the degree of distribution. When there was difference among the mean values, the Duncan's multiple range test was done to confirm the difference. Finally, methods for accessing accuracy and validity of the quality data was done by the Contingency table test. The quality data of five blood centers was showed to the normal distribution and it was in a acceptable range. For each blood centers, the monthly means of Hematocrit(Hct), Platelet(PLT) and pH were not significantly different except Hct of C center, PLT of B, D center and pH of A center. The quality data per items was graded according to quality to six level. As a result of the comparative analysis, the monthly means of Hct of C and E center was significantly different higher than that of D, B and A center. The monthly means of PLT of A center and pH of C center was significantly different higher than that of the others. In the accuracy and validity of the quality control data, C center for Hct, A center for PLT and C center for pH were better than the other. The C blood center was most satisfiable and stable in the quality control for blood component. If the quality control method used in C blood center is adopted in other blood centers, the prepared level of the blood component of the center will be improved partly.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.17-24
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• 2019

Carbon Fiber Reinforced Polymers(CFRP) has widely utilized as a material for rehabilitation because of its light-weight, deformability and workability. Because CFRP is brittle material whereas steel is ductile, it is inappropriate to apply conventional design approach for steel reinforcement. For ductile material, the behavior of combined elements is on average of that of unit element due to the stress redistribution between elements after yielding. Therefore, the mean value of the stress of combined elements is equal to that of unit element and the standard variation is smaller. Therefore, although the design value can increase, it is used as constant value because it is conservative and practical approach. However, for brittle material, the behavior of combined elements is governed by the weaker element because no stress redistribution is expected. Therefore, both the mean value and standard variation of the stress of combined elements decreases. For this reason, the design value would decrease as the number of element increases although it is eventually converged. In this paper, in brittle material, it is verified that the combination of unit element with normal distribution results in combined element with weibull distribution, so the modifying equation of mechanical properties is proposed with respect to the area load applied.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.2
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• pp.368-382
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• 1997

Through the recognition and the satisfaction of the lower part of the women body in 20s' we studied 202 respondents of the women in 20s' to analyze what lower part shape they want. And also through the measurment, we tried to analyze their wants. The results are as follows. 1. The women in 20s' think ideal body shapes are highstature, long legs, slander waist, hip, abdomen, thigh, ankle, and light weight. And so it needs to be studied to make slacks pattern which show slander girth and long length. 2. At the result of the body measurments the laterallargeness related with width, girth and depth items of the first factor rated 33.1 oyo in the variousfactors, and vertical largeness related with highness of the second fact rated 18.3% the first and the second factors affect importantly in the lower part of women body in 20s'. 3. At the result of the group analysis, the type divided five kinds, according to the body measurments, the type of 1, 3, 4, are normal, the type of 2 is weak, the type of 5 is fat. The type of 1 shows the largest distribution of all held 108, the flank is standard somatotype. The type of 2 is the second largest distribution held 59, the flank is forwardsomatotype. The type of 3 is the smallest of all types in the lateral largeness, the flankis turning over somatotype. The type of 4 is large both in the lateral largenessand in the vertical largeness, the flank is forward somatotype. The type of 5 is the fat type. The lateral type is the largest, the flank is forward turning over somatotype. The type of 5 showed the smallest distribution.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.1
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• pp.31-38
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• 2005

This paper is focused on the research of environmental and human factors for a design of PMVbased air conditioning system in the ship. In the results from environmental factor research, it is possible to dissatisfy thermally in the wheel house and communication room of 25 ton and engine room of 100 ton. The clothing and activity in the ship is modified using inland indoor characteristics. Thermal resistance of clothing may be more sensitive to PMV(predicted mean vote) than metabolic rate because of large deviation among maritime polices. The distribution of human factor is right long-tailed than standard normal distribution.