• Advances in materials Research
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• v.11 no.4
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• pp.375-390
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• 2022

Carbon Fiber Reinforced Polymer (CFRP) composite provides outstanding mechanical capabilities and is therefore popular in the automotive and aerospace industries. Drilling is a common final production technique for composite laminates however, drilling high-strength composite laminates is extremely complex and challenging. The delamination of composites during the drilling at the entry and exit of the hole has a severe impact on the results of the holes surface and the material properties. The major goal of this research is to investigate contemporary industry solutions for drilling CFRP composites: enhanced edge geometries of cutting tools. This study examined the occurrence of delamination at the entry and exit of the hole during the drilling. For each of the 80°, 90°, and 118°point angle uncoated Brad point, Dagger, and Twist solid carbide drills, Taguchi design of experiments were undertaken. Cutting parameters included three variable cutting speeds (100-125-150 m/min) and feed rates (0.1-0.2-0.3 mm/rev). Brad point drills induced less delamination than dagger and twist drills, according to the research, and the best cutting parameters were found to be a combination of maximum cutting speed, minimum feed rate, and low drill point angle (V:150 m/min, f: 0.1 mm/rev, θ: 80°). The feed rate was determined to be the most efficient factor in preventing hole entry and exit delamination using analysis of variance (ANOVA). Regression analysis was used to create first-degree mathematical models for each cutting tool's entrance and exit delamination components. The results of optimization, mathematical modelling, and experimental tests are thought to be reasonably coherent based on the information obtained.

• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.129-136
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• 2022

In this study, we aimed to develop a maturity classification model for tomatoes using hyperspectral imaging in the range of 400 - 1,000 nm. Fifty-seven tomatoes harvested in August and November of 2021 were used as the sample set, and hyperspectral data was extracted from the surfaces of these tomatoes. A combined method of SNV (standard normal variate) and SG (Savitzky-Golay) methods was used for the pre-processing of the hyperspectral data. In addition, the hyperspectral data were analyzed for all maturity stages and considering bandwidths with different FWHM (full width at half maximum) values of 2, 25, and 50 nm. The PCA (principal component analysis) method was used to analyze the principal components related to maturity stages for the tomatoes. As a result, 500 - 550 nm and 650 - 700 nm bands were found to be related to the maturity stages of tomatoes. In addition, PC1 and PC2 explained approximately 97% of the variance at all FWHM conditions and thus were used as input data for classification model training based on the SVM (support vector machine). The SVM models were able to classify tomato maturity into five stages (Green, Turning, Pink, Light red, and Red) with over 95% accuracy regardless of the FWHM condition. Therefore, it was considered that hyperspectral data with 50 nm FWHM and SVM is feasible for use in the classification of tomato maturity into five stages.

• Journal of the Korean Society of Food Culture
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• v.23 no.6
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• pp.779-792
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• 2008

The consumption of a wide variety of food groups is considered one of the key components of nutritional adequacy. The 2005 Dietary Guidelines for Koreans includes the consumption of a variety of foods from diverse food groups as a component of a normal diet. A survey was conducted to evaluate the relationship between the dietary diversity of food groups and nutrient intake in elderly patients (age 65 and above) at a rural area in Korea (Inje). 296 subjects (111 male and 185 female) were probed in a 3 day 24-recall dietary survey. Subjects were grouped according to food group intake frequency, based on six food groups (grain, meat/fish/legume/egg, vegetable, fat/oil, dairy, fruit). Nutritional quality was evaluated according to the numbers of nutrients under EAR (Estimated Average Requirements), and MAR (mean adequacy ratios). The frequency of elderly subjects consuming a meat/fish/legumes/egg food group less than once per day was 29.4%. The frequency of elderly subjects consuming fat/oil food group less than once per day was 65.8%. The percentage of subjects who did not eat dairy food was 88.8%, and that of subjects who did not eat fruit was 57.5%. A stepwise multiple regression analysis was used to develop models relating nutritional quality to possible food group intake frequency factors. Using the number of nutrients under EAR as a dependent variable, the meat/fish/legume/egg food group intake frequency explained 9.9% of variance, followed by the grain group, fat/oil group, dairy group, and vegetable and fruit group (Model $R^2$=0.260). For mean nutrient adequacy ratio as a dependent variable, the model $R^2$ was 0.326. The results of this study suggest that a highly varied diet in elderly might be associated with better nutritional quality, as assessed by nutrient intake. Accordingly, dietary guidelines should take into consideration nutritional characteristics in order to improve intake from all major food groups and to provide a variety of foods in the diet.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.509-516
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• 2004

This study is to investigate the amount of biased estimates for heritability and genetic correlation according to data structure on marbling scores in Korean cattle. Breeding population with 5 generations were simulated by way of selection for carcass weight, Longissimus muscle area and latent values of marbling scores and random mating. Latent variables of marbling scores were categorized into five by the thresholds of 0, I, 2, and 3 SD(DSI) or seven by the thresholds of -2, -1, 0,1I, 2, and 3 SD(DS2). Variance components and genetic pararneters(Heritabilities and Genetic correlations) were estimated by restricted maximum likelihood on multivariate linear mixed animal models and by Gibbs sampling algorithms on multivariate threshold mixed animal models in DS1 and DS2. Simulation was performed for 10 replicates and averages and empirical standard deviation were calculated. Using REML, heritabilitis of marbling score were under-estimated as 0.315 and 0.462 on DS1 and DS2, respectively, with comparison of the pararneter(0.500). Otherwise, using Gibbs sampling in the multivariate threshold animal models, these estimates did not significantly differ to the parameter. Residual correlations of marbling score to other traits were reduced with comparing the parameters when using REML algorithm with assuming linear and normal distribution. This would be due to loss of information and therefore, reduced variation on marbling score. As concluding, genetic variation of marbling would be well defined if liability concepts were adopted on marbling score and implemented threshold mixed model on genetic parameter estimation in Korean cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.459-464
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• 2009

Data and pedigree information for Lori-Bakhtiari sheep used in this study were 6,239 records of lamb mortality from 246 sires and 1,721 dams, collected from 1989 through 2007 from a Lori-Bakhtiari flock at Shooli station in Shahrekord. The traits investigated were cumulative lamb mortality from birth up to 7 days, up to 14 days, up to 21 days, and up to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 months of age. The models included fixed factors that had significant effects and random direct genetic, maternal genetic and maternal permanent environmental effects. Variance components were estimated using the restricted maximum likelihood procedure applying three animal models with and without maternal and common environmental effects. The overall mean of cumulative lamb mortality rate was 22.95% from birth to 1 year of age, while the overall mortality rate up to 3 and from 3 to 6 months of age was 6.14% and 12.76%, respectively. The mortality rate after 6 months of age declined as the lambs grew older. The age of dam had no important effect on lamb mortality. The type of birth was more important during the preweaning period than at later ages, and lamb mortality rate was higher in twins. The year of birth, month of birth and sex of lamb significantly (p${\leq}$0.01) affected the cumulative lamb mortality rate at all ages. The least square mean of mortality during the final one-third of the lambing period was higher than the first and middle onethird of the lambing period. Male lambs were found to be at a higher risk of mortality than females. Birth weight of the lamb had a highly significant (p${\leq}$0.01) effect on lamb mortality at all ages as a quadratic regression. Direct and maternal heritability estimates of lamb mortality ranged from 0.01 to 0.13 and 0.01 to 0.05, respectively. Direct heritability increased with age of lamb, while maternal effects (genetic and common environmental) were important in the preweaning period. These results indicate that lamb mortality can be reduced first through farm management practices and secondly by genetic selection. Both animal and maternal effects should be considered in breeding programmes for reducing lamb mortality at preweaning.

• Quality Improvement in Health Care
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• v.1 no.2
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• pp.60-72
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• 1994

Background: The number of outpatients visiting large university teaching hospitals has increased drastically with the introduction of a nationwide health care insurance in 1989 and the improvement of the socio-economic status of the population. This resulted in long waiting times for services, particularly prescribed drugs, which have been patients' chief complaints. Hospitals have tried to solve the problem with limited success because their approach lacked comprehensive research. The objective of this study is to investigate associations between waiting times and variables defining a total work system. Methods: Data for the outpatient pharmacy department in a tertiary care university teaching hospital located in Seoul was analyzed to achieve the study objective. Associations of pharmacy system variables -- work load, work force, pharmacist work schedule, machine problems, and inventory control -- with mean and 99th percentile of waiting times were examined by the hierarchical stepwise regression method. Day was a unit of the analyses. Results: The regression models explained 65.8% of variance in the mean waiting time and 61.34% in the 99th percentile of waiting times. The break-down of the printer for drug envelops, Automatic Tablet Counters (ATCs), and main computer system lasted longer than 30 minutes increased the mean for 7.7 minutes, 4.5 minutes, and 7.0 minutes, respectively, and the 99th percentile for 14.8 minutes, 9.0 minutes, and 15.7 minutes, respectively. Concerning the work force, study results showed that there were significant differences in the productivity of pharmacists with work experience more than three years, one to three years, and less than one year, and showed that peak time aid work by pharmacists at job assignments other than the outpatient pharmacy, part-time pharmacists, and the installation of ATCs were effective in reducing waiting times, Finally, study findings indicated that the operational policy of work assignment and rotation schedule, supply and inventory of drugs at work tables, and readiness for undisrupted work during the work hours could have a significant effect on waiting times. Conclusion: The study results indicated that efforts to reduce waiting times for prescribed drugs should be geared toward every components of the pharmacy work system ranging from work schedule of pharmacists and supply of dugs at work tables. These findings should provide hospital managers with right directions in battling the problem.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.171-176
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• 2007

A total of 4,627 records on pre-weaning growth traits, birth weight(BW), weaning weight(WW) and pre-weaning daily gain(ADG) of Hanwoo’s born form 1970 to 2005 were collected from Hanwoo Experiment Station, National Livestock Research Institute. Variance components and heritabilities of BW, WW and ADG were estimated with two models; Model 1 included only direct genetic effect while Mode1 2 included direct genetic, maternal genetic and permanent environmental effects. Direct herit- ability estimates of BW, WW and ADG estimated by model 1 were 0.34, 0.26 and 0.20, respectively. In model 2, direct heritability and maternal genetic heritability estimates were 0.14 and 0.06 for BW, 0.07 and 0.04 for WW and 0.05 and 0.04 for ADG. Estimates of genetic correlation between direct and maternal effect for BW, WW and ADG were 0.58, 0.75 and 0.61, respectively. Genetic correlation coefficients between BW and WW, between BW and ADG, and between WW and ADG were 0.76, 0.62 and 0.99, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.151-162
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• 2012

Analysis for back fat thickness (BFAT) and daily body weight gains from birth to the end of a performance test were conducted to find an optimal method for estimation of weaning age effects and to ascertain impacts of weaning age on the growth performance of purebred Berkshire pigs from a closed population in Korea. Individual body weights were measured at birth (B), at weaning (W: mean, 22.9 d), at the beginning of the performance test (P: mean, 72.7 d), and at the end of the performance test (T: mean, 152.4 d). Further, the average daily gains in body weight (ADG) of 3,713 pigs were analyzed for the following periods: B to W (DGBW), W to P (DGWP), P to T (DGPT), B to P (DGBP), B to T (DGBT), and W to T (DGWT). Weaning ages ranged from 17 to 34 d, and were treated as fixed (WF), random with (WC) and random without (WU) consideration of an empirical relationship between weaning ages in the models. WF and WC produced the lowest AIC (Akaike Information Criterion) and least fractions of error variance components in multi-traits analysis, respectively. The fractions of variances due to diverse weaning age and the weaning age correlations among ADGs of different stages (when no overlapping allowed) by WC ranged from 0.09 to 0.35 and from -0.03 to 0.44, respectively. The maximum weaning age effects and optimal back fat thicknesses were attained at weaning ages of 27 to 32 d. With the exception of DGBW, the effects of weaning age on the ADGs increased (ranging from 1.50 g/d to 7.14 g/d) with increased weaning age. In addition, BFAT was reduced by 0.106 mm per increased day in weaning age. In conclusion, WC produced reasonable weaning age correlations, and improved the fitness of the model. Weaning age was one of crucial factors (comparable with heritability) influencing growth performance in Berkshire pigs. Further, these studies suggest that increasing weaning age up to 32 d can be an effective management strategy to improve growth performance. However, additional investigations of the costs and losses related to extension of the suckling period and on the extended range of weaning age are necessary to determine the productivity and safety of this practice in a commercial herd and production system.

• Journal of Nutrition and Health
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• v.54 no.1
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• pp.116-128
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• 2021

Purpose: The extraction conditions for bioactive components from peanut shells, which is a byproduct of peanut processing, were optimized to enhance the total phenolic content (TPC, Y1), total flavonoid content (TFC, Y2), and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (RSA, Y3). In addition, this study evaluated the anti-obesity effect of peanut shell extract. Methods: Optimization of ultrasonic-assisted extraction (UAE) was performed using a response surface methodology. The independent variables applied for extraction were time (X1: 5.0-55.0), temperature (X2: 26.0-94.0), and ethanol concentration (X3: 0.0%-99.5%). Quadratic regression models were derived based on the results of 17 experimental sets, and an analysis of the variance was performed to verify its accuracy and precision of the regression equations. Results: When evaluating the effects of independent variables on responses using statistically-based optimization, the independent variable with the most significant effect on the TPC, TFC, and RSA was the ethanol concentration (p = 0.0008). The optimal extraction conditions to satisfy all three responses were 35.8 minutes, 82.7℃, and 96.0% ethanol. Under these conditions, the inhibitory activities of α-glucosidase and pancreatic lipase by the extract were 86.4% and 78.5%, respectively. Conclusion: In this study, UAE showed superior extraction efficiency compared to conventional hot-water extraction in the extraction of polyphenols and bioactive materials. In addition, α-glucosidase and pancreatic lipase inhibitory effects were identified, suggesting that peanut shells can be used as effective antioxidants and anti-obesity agents in functional foods and medicines.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.1
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• pp.162-170
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• 1998

The purpose of this study is to provide framework for understanding children's dental utilization. In this paper Andersen-Newman's model is applied to the use of dental visits. This model consists of predisposing, enabling, and need components that describe a person's decision to use dental health services. One thousand, nine hundred seven children and their mothers were selected for the study. The children were fourth grade to sixth grade in elementary schools in Iksan city, Korea. Models are operationalized using stepwise multiple regression analysis and path analysis. The number of independent variables used in the analysis was 39 in total, ie 32 predisposing components, 6 enabling components, and 1 need component. Children's Dental utilization was measured based on the number of visits. The data collected by means of a questionnaire survey. In this study, the amount of variance by the model was 25 percent. Predisposing factors had the greatest effect on utilization. Number of restricted activity days caused by oral disease, having a regular dental care, and susceptibility on oral disease of children were found to have significant major effects on dental utilization of children. Mother's dental visits was most important factor affecting dental utilization of children.