• Composites Research
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• v.36 no.2
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• pp.108-116
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• 2023

In this paper, kinematic design and multi-body dynamics analysis were conducted to develop a small manipulator platform for automating the maintenance of structures made of composite materials. To design manipulator kinematically, the existing composite repair process was considered. The 3D design was conducted after selecting the basic specifications of manipulator and end-effecter in consideration of the patch lamination process for repair. Then, variables necessary for simulation and control were generated in MATLAB through inverse kinematic analysis. To evaluate the structural stability of platform, multibody dynamics analysis was conducted using Altair Inspire and Optistruct. Based on the simulation conducted in Inspire, multibody dynamics analysis was conducted in Optistruct, and structural stability was verified through the results of maximum displacement and Von-Mises stress over time. To verify the design, manufacturing and controlling of platform were conducted and compared with the simulation. It was confirmed that the actual repair process path and the simulation showed a good agreement.

• Computers and Concrete
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• v.32 no.2
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• pp.217-232
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• 2023

Numerous studies have been performed on the behavior of pile foundations in cold regions. This study first attempted to employ artificial neural networks (ANN) to predict pile-bearing capacity focusing on pile data recorded primarily on cold regions. As the ANN technique has disadvantages such as finding global minima or slower convergence rates, this study in the second phase deals with the development of an ANN-based predictive model improved with an Elephant herding optimizer (EHO), Dragonfly Algorithm (DA), Genetic Algorithm (GA), and Evolution Strategy (ES) methods for predicting the piles' bearing capacity. The network inputs included the pile geometrical features, pile area (m²), pile length (m), internal friction angle along the pile body and pile tip (Ø°), and effective vertical stress. The MLP model pile's output was the ultimate bearing capacity. A sensitivity analysis was performed to determine the optimum parameters to select the best predictive model. A trial-and-error technique was also used to find the optimum network architecture and the number of hidden nodes. According to the results, there is a good consistency between the pile-bearing DA-MLP-predicted capacities and the measured bearing capacities. Based on the R2 and determination coefficient as 0.90364 and 0.8643 for testing and training datasets, respectively, it is suggested that the DA-MLP model can be effectively implemented with higher reliability, efficiency, and practicability to predict the bearing capacity of piles.

• Journal of Korean Biological Nursing Science
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• v.25 no.1
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• pp.73-85
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• 2023

Purpose: This study focused on identifying the interaction effects of genetic and lifestyle-environmental factors on the development of type 2 diabetes mellitus (T2D). Methods: Study subjects were selected from the Korean Genome and Epidemiology Study (KoGES) from 2001 to 2014. Data on genetic variations, anthropometric measurements, biochemical data, and seven lifestyle factors (diet, physical activity, alcohol drinking, smoking, sleep, depression, and stress) were obtained from 4,836 Koreans aged between 40 and 59 years, including those with T2D at baseline (n = 1,209), newly developed T2D (n= 1,298) and verified controls (n = 3,538). The genetic risk score (GRS) was calculated by using 11 single-nucleotide polymorphisms (SNPs) related to T2D development and the second quartile was used as the reference category. A Cox proportional hazards regression model was used to evaluate the associations of GRS and lifestyle factors with T2D risk, controlling for covariates. Results: Multivariate regression analysis revealed that GRS was the strongest risk factor for T2D, and body mass index (BMI), smoking, drinking, and spicy food preference also increased the risk. Lifestyle/environmental factors that showed significant interactions with GRS were BMI, current smoking, current drinking, fatty food preference, and spicy food preference. Conclusions: Interactions between genetic factors and lifestyle/environmental factors were associated with an increased risk of T2D. The results will be useful to provide a new perspective on genetic profiling for the earlier detection of T2D risk and clues for personalized interventions, which might be more effective prevention strategies or therapies in individuals with a genetic predisposition to T2D.

• Journal of Veterinary Clinics
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• v.40 no.3
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• pp.238-241
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• 2023

This study determined the effect of ovarian status at the beginning of the modified Double-Ovsynch program on reproductive performance in dairy cows. In the study, 1,302 cows were treated with a modified Double-Ovsynch program at 56 days after calving. This program comprises administering gonadotropin-releasing hormones (GnRH), prostaglandin F_2α (PGF_2α) 10 days later, GnRH 3 days later, GnRH 7 days later, and GnRH 56 h later, followed by timed artificial insemination (TAI) 16 h later. At the beginning of the program, cows were categorized according to the size of the largest follicle and the presence of a corpus luteum (CL) in the ovaries as follows: 1) small follicle (<5 mm, SF group, n = 100), 2) medium follicle (8-20 mm, MF group, n = 538), and 3) large follicle (≥25 mm, LF group, n = 354) without a CL, or 4) the presence of a CL (CL group, n = 310). The pregnancies per AI after the first TAI were analyzed by logistic regression using the LOGISTIC procedure, and the logistic model included the fixed effects of the herd size, parity, body condition score (BCS) at the first TAI, TAI period, and ovarian status. A larger herd size, higher BCS at the first TAI, and TAI period with no heat stress increased (p < 0.05) the probability of pregnancy per AI after the first TAI. However, ovarian status at the beginning of the program did not affect (p > 0.05) the pregnancies per AI (ranges of 37.9% to 42.9%). These results show that the modified Double-Ovsynch program can be used effectively while maintaining good fertility regardless of the ovarian status in dairy herds.

• Journal of the Korean Society of Food Culture
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• v.22 no.6
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• pp.665-672
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• 2007

The purpose of this study was to investigate the eating habits and eating behaviors, nutrition knowledge of students in 4, 5 and 6th graders of elementary school in Jeonju Area. The subjects for questionnaire were 2,568 elementary school students (boys 1,364, girls 1,204). The results were analyzed by SPSS program, and were as follows. In anthropometric data, there were significant differences between boys and girls. In eating habits and eating behaviors, there were significant differences in the rate of 'Hasty eating habit(p<0.01)', 'Most heavy meal(p<0.01)', 'Eating when receive stress(p<0.05)', and 'Frequency of snack eating per day(p<0.01)' between boys and girls. In total scores of nutrition knowledge, there were significant differences between boys and girls. In nutrition knowledge, there were significant differences in the rate of 'Carbohydrate and fat give heat and force.(p<0.001)', 'Carbohydrate is nutrient that make muscle and blood of our body.(p<0.01)', 'Overeating of carbohydrate does not contribute gain of weight. (p<0.05)', To intake vitamin, it is good to eat fresh fruit and vegetable.(p<0.01)', 'Calcium deficiency is leading to anemia.(p<0.001)' between boys and girls. In conclusion, systematical educational programs need to be developed at elementary school. These should include information about achieving a balanced diet, good eating habit and behavior, meal management and Korean dietary culture. Also, nutritional education at home must be emphasized.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.298-307
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• 2023

Objectives: The purpose of this study is to analyze the recent trends in patients with work-related musculoskeletal disorders in South Korea and to check the major results by reviewing the literature on the risk factors and prevalence of musculoskeletal diseases related to work. Methods: Industrial disaster data from the Ministry of Employment and Labor from 2012 to 2021 were used, and the literature was reviewed regarding risk factors for musculoskeletal diseases related to work using PubMed and RISS. Results: The trend of patients with work-related musculoskeletal disorders has increased overall since 2017 after declining until 2016, with a particularly notable increase in the average annual number of patients with physical burden work. The average annual rate per ten thousand people for patients with body burden work, non-accidental lower back pain, and carpal tunnel syndrome among work-related diseases was high in the mining industry. The average annual rate per ten thousand people for patients with accidental lower back pain was the highest in the fishing industry. Within the manufacturing field, it was the highest in the shipbuilding and ship repair industry. As a result of the literature review, the search rate for work-related musculoskeletal disease papers in unstructured work was high. In addition, physical stress factors were high among risk factors, and pain areas showed a high rate for the waist. Conclusion: Even after the institutional implementation of a hazard investigation system related to musculoskeletal diseases is implemented, the number of patients with occupational musculoskeletal disorders continues to increase. Therefore, it is necessary to conduct regular surveys and implement effective improvement activities for vulnerable industries or occupations.

• Journal of Korean Physical Therapy Science
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• v.30 no.4
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• pp.71-81
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• 2023

Background: The purpose of this study was to comparison and correlation between physical and psychological functions by gender in Judo athletes. Both the physical and psychological factors of athletes are important as factors influencing athletic performance, but there are few papers that have compared and studied the correlation between physical and psychological functions of judo players. Design: Cross sectional study Methods: The 134 participants; high school students, college students, and team players. They used physical functions to measure such as self-describing KOOS, FAOS, ODI, POMS, SCAT, ASMQ, and ACSI-28. Results: There was a significant difference in the physical function according to gender in the KOOS, but no significant difference in the FAOS and ODI. For psychological function, there was a significant difference in the vitality item in the POMS, and a significant difference in the body management, training management, life management, and unique behavior management items in the ASMQ. In the ACSI-28, there were significant differences in coping with adversity, stress repayment, concentration, freedom to worry about matches, and self-coaching behavior items. Physical function and psychological function showed a significant negative correlation. The POMS showed a negative correlation between the ASMQ and ACSI-28, whereas the SCAT showed a positive correlation. Conclusion: The results of this study are expected to be used as a basic data for sports training by gender of Judo athletes.

• Journal of the Korean Society of School Health
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• v.36 no.3
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• pp.113-125
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• 2023

Purpose: The purpose of this study is to develop a model for predicting mental health risk among adolescents based on health behavior information by employing a hybrid machine learning method. Methods: The study analyzed data of 51,850 domestic middle and high school students from 2022 Youth Health Behavior Survey conducted by the Korea Disease Control and Prevention Agency. Firstly, mental health risk levels (stress perception, suicidal thoughts, suicide attempts, suicide plans, experiences of sadness and despair, loneliness, and generalized anxiety disorder) were classified using the k-mean unsupervised learning technique. Secondly, demographic factors (family economic status, gender, age), academic performance, physical health (body mass index, moderate-intensity exercise, subjective health perception, oral health perception), daily life habits (sleep time, wake-up time, smartphone use time, difficulty recovering from fatigue), eating habits (consumption of high-caffeine drinks, sweet drinks, late-night snacks), violence victimization, and deviance (drinking, smoking experience) data were input to develop a random forest model predicting mental health risk, using logistic and XGBoosting. The model and its prediction performance were compared. Results: First, the subjects were classified into two mental health groups using k-mean unsupervised learning, with the high mental health risk group constituting 26.45% of the total sample (13,712 adolescents). This mental health risk group included most of the adolescents who had made suicide plans (95.1%) or attempted suicide (96.7%). Second, the predictive performance of the random forest model for classifying mental health risk groups significantly outperformed that of the reference model (AUC=.94). Predictors of high importance were 'difficulty recovering from daytime fatigue' and 'subjective health perception'. Conclusion: Based on an understanding of adolescent health behavior information, it is possible to predict the mental health risk levels of adolescents and make interventions in advance.

• Journal of TMJ Balancing Medicine
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• v.13 no.sup
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• pp.1-8
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• 2023

Objectives: Parkinson's disease (PD) is currently the most rapidly increasing degenerative brain disease due to population aging and westernization of lifestyle. Levodopa is the most commonly used drug to manage PD symptoms. However, levodopa has a problem in that the wearing-off phenomenon occurs as the duration and dose of administration increase. In order to investigate the wearing-off phenomenon in PD patients and devise countermeasures, we conducted a questionnaire survey in Korea. Methods: For the study, a questionnaire with a total of seven items was prepared. Part IV of the MDS-UPDRS (Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale) and the WOQ-9 (9-symptom Wearing-off Questionnaire) were used as references. Results: Of the 48 patients who completed the questionnaire, all 47 patients who completed the questionnaire experienced the wearing-off phenomenon. Only one of the patients diagnosed with PD a year ago did not experience the wearing-off phenomenon. Patients frequently mentioned a lack of sleep and stress as aggravating factors for wearing-off. They also stated that in order to resolve the off-state, they walked, massaged, warmed up the body, stretched and exercised. Conclusions: Because wearing-off is such a common occurrence, it is thought necessary to develop wearing-off prevention and resolution measures that PD patients can use in their daily lives.

• Journal of the Korean Society of Safety
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• v.39 no.1
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• pp.9-15
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• 2024

Hydrogen-based electricity and transportation systems are widely recognized as sustainable power sources. However, the low ignition energy of hydrogen, only 1/10th that of conventional fossil fuels, poses a safety concern involving the risk of ignition due to electrostatic discharge from facility workers. Therefore, anti-static systems are imperative for hydrogen-based electricity facilities. To address this, we propose a reliable conductive rubber mat (CRM) to ensure the safety of these facilities. Unlike conventional anti-static floors that utilize conductive paint (CP), the CRM features a uniform distribution of conductive components in chemically and mechanically stable rubber. As a result, the CRM is unyielding to polar solvents (such as ethanol and hydrosulfuric acid) and non-polar solvents (like mineral oil) without increasing its resistance. Moreover, the CRM can withstand mechanical stress. Consequently, the human-body voltage of workers on the CRM would be sufficiently low enough to protect them from hydrogen explosions, thereby enhancing overall safety.