• Asian-Australasian Journal of Animal Sciences
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• v.31 no.1
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• pp.26-31
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• 2018

Objective: This study estimated the genetic parameters for body weight gain and growth curve parameter traits in Korean native chicken (KNC). Methods: A total of 585 $F_1$ chickens were used along with 88 of their $F_0$ birds. Body weights were measured every 2 weeks from hatching to 20 weeks of age to measure weight gain at 2-week intervals. For each individual, a logistic growth curve model was fitted to the longitudinal growth dataset to obtain three growth curve parameters (${\alpha}$, asymptotic final body weight; ${\beta}$, inflection point; and ${\gamma}$, constant scale that was proportional to the overall growth rate). Genetic parameters were estimated based on the linear-mixed model using a restricted maximum likelihood method. Results: Heritability estimates of body weight gain traits were low to high (0.057 to 0.458). Heritability estimates for ${\alpha}$, ${\beta}$, and ${\gamma}$ were $0.211{\pm}0.08$, $0.249{\pm}0.09$, and $0.095{\pm}0.06$, respectively. Both genetic and phenotypic correlations between weight gain traits ranged from -0.527 to 0.993. Genetic and phenotypic correlation between the growth curve parameters and weight gain traits ranged from -0.968 to 0.987. Conclusion: Based on the results of this study population, we suggest that the KNC could be used for selective breeding between 6 and 8 weeks of age to enhance the overall genetic improvement of growth traits. After validation of these results in independent studies, these findings will be useful for further optimization of breeding programs for KNC.

• Journal of Veterinary Clinics
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• v.26 no.2
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• pp.134-137
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• 2009

Although there is circumstantial evidence that infectious bronchitis(IB) in the Korean layer industry has contributed to severe economic losses, the seroprevalence against IB virus(IBV) and risk factors associated with seropositivity are not well known. During May to October 2007, 820 blood samples were randomly collected from 41 laying hen flocks(20 birds in each flock) with $\geq$ 3,000 birds of 18 week of age or older in three provinces of Korea. The samples size was determined considering a flock-size range of 3,000-65,000 birds, an expected bird-level seroprevalence of $\geq$ 15%, and a 95% level of confidence. Serum samples were examined using a hemagglutination inhibition test for antibodies to IBV. The overall apparent flock-level seroprevalence was 46.3%(95% CI, 31.1-66.6) with no statistically significant differences among provinces(X=1.205, p>0.05). There were 19 positive flocks with one to eight seropositive birds, and 11 of these had one or two seropositive birds. None of the measured parameters were significantly associated with seropositivity against IBV in a subsequent multivariable logistic regression analysis. A longitudinal risk factor studies considering management and vaccination characteristics possibly associated with the IBV flock prevalence would be beneficial.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.575-583
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• 2017

This paper describes the design and evaluation of a driving mode decision algorithm for automated driving for merge situations on highways. For the development of a highly automated driving control algorithm for merge situations, the driving mode decision is crucial for merging appropriately. There are two driving modes: lane keeping and lane changing (merging). The merge mode decision is determined based on the state of the surrounding vehicles and the remaining length of the merge lane. In the merge mode decision algorithm, merge possibility and the desired merge position are decided to change the lane safely and quickly. A safety driving envelope is defined based on the desired driving mode using the information on the surrounding vehicles' behaviors. To obtain the desired steering angle and longitudinal acceleration for maintaining the subject vehicle in the safe driving envelope, a motion planning controller is designed using model predictive control (MPC), with constraints that are decided considering the vehicle dynamics, safe driving envelope, and actuator limit. The proposed control algorithm has been evaluated via computer simulation studies.

• Journal of Preventive Medicine and Public Health
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• v.40 no.5
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• pp.388-396
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• 2007

Objectives: The purpose of this study was to examine the relationship between the differences in employment status and self assessed health in Korea. Methods: We analyzed 4 year follow-up data generated by the Korean Labor and Income Panel Study(KLIPS), which was conducted on 1,207 men and 582 women who had undergone a change in employment status. The study subjects were placed into 1 of the following 4 groups based on their employment history; Non-precarious workers, Precarious to non-precarious workers, Non-precarious to precarious workers and Precarious workers. Logistic regression was then used to examine the relationship between the changes in employment status and self assessed health. Results: When males were considered, self assessed health was better among the precarious to non-precarious workers (OR 1.58, 95% CI=1.57-1.60) and the precarious workers (OR 1.29, 95% CI=1.28-1.30) than in the non-precarious workers, after adjusting for age, socioeconomic status (education level, occupational class, marital status, average equivalent household income and average number of hours worked per week), health behavior (smoking, drinking and exercise) and medical service access (regular medical examination, have chronic disease or hospitalized within 1 year). When female workers were considered, the precarious to non-precarious workers (OR 1.89, 95% CI=1.86-1.92), non-precarious to precarious workers(OR 1.24, 95% CI=1.23-1.26) and precarious workers (OR 1.27, 95% CI=1.25-1.28) all reported poorer health than the non-precarious workers after adjusting for the aforementioned factors. Conclusions: This study showed that changes in employment status were associated with differences in self assessed health among men and women. Specifically, the results of this study showed that a corresponding positive outcome based on self assessed health was greater for employees that changed from precarious to non-precarious jobs and for male employees with precarious jobs., whereas female employees with non-precarious jobs had higher self assessed health. However, additional longitudinal studies on the health effects of employment status should be conducted.

• Journal of Korean Society of Transportation
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• v.36 no.2
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• pp.98-111
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• 2018

Truck platooning, which is a cluster of trucks in support of vehicle-to-vehicle communication and automated longitudinal vehicle control, is a promising method to both operational efficiency and prevent traffic crashes. Although a variety of studies have been conducted to identify the effects of vehicle platooning on traffic stream, we are not aware of any study attempting to identify promising road segments for vehicle platooning. This study aims to develop a methodology for determining the priority of freeway segments that would potentially lead to maximize the effectiveness of truck platooning. Evaluation measures derived in this study includes truck crash rates, the percentage of truck traffic, segment length, and the number of entry and exit points. Weighting values obtained from an analytical hierarchical process (AHP) method were applied to compute the proposed priority score to determine better freeway segment for truck platooning. Results suggested that a 46.9km freeway segment, from Sacheon IC to Sanin JC, was the most promising segment for maximizing the effectiveness of truck platooning. It is expected that the outcome of this study would be effectively used as a fundamental to establish operational strategies for truck platooning.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.204-211
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• 2011

A dynamic analysis procedure is developed to provide a better estimation of the dynamic responses of bridge during the passage of high speed railway vehicles. Particularly, a three dimensional numerical model including the structural interaction between high speed vehicles, bridges and railway endures to analyse accurately and evaluate with in-depth parametric studies for dynamic responses of various bridge span lengths running KTX railway locomotive up to increasing maximum speed(450km/h). Three dimensional frame element is used to model the simply supported pre-stressed concrete (PSC) box bridges for four span lengths(40~25m). Track irregularity employed as a stationary random process from the given spectral density functions and irregularities of both sides of the track are assumed to have high correlation. The high-speed railway vehicle (KTX) is used as 38-degree of freedom system. Three displacements (Vertical, lateral, and longitudinal) as well as three rotational components (Pitching, rolling, and yawing) are considered in the 38-degree of freedom model. The dynamic amplification factors are evaluated by the developed procedure under various traveling conditions, such as track irregularity camber, train speed and ballast. The dynamic analysis such as Newmark-${\beta}$ and Runge-Kutta methods which are able to analyse considering the dynamic impact factors are compared and contrasted.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.287-293
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• 2016

This study aims to look into the effects of ego-resilience and social support on school adjustment of dormitory high school students in the convergence age. For achieving this purpose, a survey with 358 students in an autonomous private high school situated in D area was conducted. For analysis of the collected data, regression analysis was carried out using SPSS WIN 20.0. As a result, it was found that ego-resilience positively affected school adjustment, and optimism, curiosity and emotional control, which are sub-factors of ego-resilience, positively affected it, too. Also, social support positively influenced school adjustment, and peer support and teacher support that are sub-factors of social support, positively influenced it, too. Therefore, it is considered that developing various programs and school culture for improving ego-resilience and providing social support to prevent a lot of problems caused by school maladjustment of high school students in the digital convergence era will positively influence individual students, schools, families and furthermore general sections of the society, and diverse interdisciplinary convergence studies on this will serve as the foundation for future longitudinal research.

• Korean Journal of Health Education and Promotion
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• v.19 no.4
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• pp.77-97
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• 2002

Since growth promotion was defined by Koch(1935), many researches like Benholdt and Thomsen(1942) have conducted studies for understanding problem of puberty growth. Growth promotion means that growth is developed in puberty, and several researchers have reported that the more becomes economic growth, the more becomes growth promotion. Thereupon, this study was attempted to find Maximum Growth Age(M.G.A.), as an index of height growth promotion in Korea, which was obtained by longitudinal observations of the same group. Thus, this study can explain the earlier tendency of growth. To investigate domestic changes in M.G.A., M.G.A. was calculated with the results of cross-sectional researchs using 25 representative papers between 1940-1953 including measurements by Lee(1940) and data by Kim(1953) in this study. Based on the research data published between 1940 and 2000, height and M.G.A. of males and females who were born between 1925 and 1983 were gotten by years, and a trend of growth promotion for height in Koreans was suggested by examining study subjects. Findings of this study are as follows; 1. M.G.A. for height decreased both in males and females; for males, 14.28 years in 1940, 14.24 in 1953, 13.86 in 1967, 12.74 in 1985, and 11.71 in 2000; for females, 12.0 in 1940, 11.52 in 1965, 10.00 in 1978 and 9.77 in 2000. 2. Regression equations and standard errors of estimate concerning M.G.A. for height by years were obtained; for males, Y$_1$(M.G.A.) = 17.21 - 0.059X$_1$, S$_{Y1X1}$(standard error of estimate about the regression line) = ${\pm}$0.62; for females, Y$_2$(M.G.A.) = 13.81-0.042X$_2$, S$_{Y2X2}$(standard error of estimate about the regression line) = ${\pm}$0.64 3. As a result of finding correlation between year and M.G.A. r=-0.763 (p<0.001) for male and r=-0.699(p<0.001) for female were obtained 4. From a view that the growth promotion has been continued before 2000, M.G.A. decreased 0.6 years for male and 0.4 for female per 10 years. 5. M.G.A. for height is as shown in Table 2. 6. It is thought that the future trend of growth promotion for height will follow the progress from 1940s to now. It shall be reviewed again after development of coming several years is investigated.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.179-190
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• 2012

The installation of an implant in the distal extension area to assist a partial dentrue (IARPD) was used carefully in clinical situations. The purpose of this review on the IARPD is describing the concept, clinical results and guidelines of IARPD. For the review, a literature search was performed using the PubMed. The data from the literature suggest that the placement of the implants could improve function and patient satisfaction. In addition, IARPD reduced the residual ridge resorption. Longer and wider implant should be placed. Less than $15^{\circ}$ angulation may be not harmful. To prevent the loosening of the abutment, modified abutment or resilient attachment should be used. However, the connection method between the clasp retention and IARPD should be considered for long time success. Moreover, longitudinal clinical studies are required for evaluation of IARPD.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.223-228
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• 2015

This study aims to verify the effect of the strength note program by comparing and analyzing the effect of the strength note program on self-esteem and self-efficacy of university students in Convergence Age. This study targeted 70 male and female university students in G area and the subjects were asked to find their and other people's positive characteristics or strengths once a week and record them. For analysis of the collected data, frequency and percentage analysis and paired-t-test were conducted using SPSS WIN 20.0. As the result, the strength note program significantly influenced the improvement in self-esteem and self-efficacy of university students. This result demonstrates the necessity of the strength note program for improving self-esteem and self-efficacy of university students. Therefore, there is a need to provide a specific and systematic strength note program to help university students get over diverse problems. It is considered that this will help mental health, academic achievement and career search of university students and contribute to the enhancement in happiness and the quality of life. Also it will be the basis for future longitudinal studies through interdisciplinary convergency research.