• Structural Engineering and Mechanics
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• v.45 no.5
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• pp.677-691
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• 2013

A semi-analytical finite strip method is developed for analyzing the post-buckling behavior of rectangular composite laminated plates of arbitrary lay-up subjected to progressive end-shortening in their plane and to normal pressure loading. In this method, all the displacements are postulated by the appropriate harmonic shape functions in the longitudinal direction and polynomial interpolation functions in the transverse direction. Thin or thick plates are assumed and correspondingly the Classical Plate Theory (CPT) or Higher Order Plate Theory (HOPT) is applied. The in-plane transverse deflection is allowed at the loaded ends of the plate, whilst the same deflection at the unloaded edges is either allowed to occur or completely restrained. Geometric non-linearity is introduced in the strain-displacement equations in the manner of the von-Karman assumptions. The formulations of the finite strip methods are based on the concept of the principle of the minimum potential energy. The Newton-Raphson method is used to solve the non-linear equilibrium equations. A number of applications involving isotropic plates, symmetric and unsymmetric cross-ply laminates are described to investigate the through-thickness shearing effects as well as the effect of pressure loading, end-shortening and boundary conditions. The study of the results has revealed that the response of the composite laminated plates is particularly influenced by the application of the Higher Order Plate Theory (HOPT) and normal pressure loading. In the relatively thick plates, the HOPT results have more accuracy than CPT.

• Smart Structures and Systems
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• v.22 no.4
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• pp.481-493
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• 2018

Ultrasonic guided waves have attracted increasing attention for non-destructive testing (NDT) and structural health monitoring (SHM) of bridge cables. They offer advantages like single measurement, wide coverage of acoustical field, and long-range propagation capability. To design defect detection systems, it is essential to understand how guided waves propagate in cables and how to select the optimal excitation frequency and mode. However, certain cable characteristics such as multiple wires, anchorage, and polyethylene (PE) sheath increase the complexity in analyzing the guided wave propagation. In this study, guided wave modes for multi-wire bridge cables are identified by using a semi-analytical finite element (SAFE) technique to obtain relevant dispersion curves. Numerical results indicated that the number of guided wave modes increases, the length of the flat region with a low frequency of L(0,1) mode becomes shorter, and the cutoff frequency for high order longitudinal wave modes becomes lower, as the number of steel wires in a cable increases. These findings were used in design of transducers for defect detection and selection of the optimal wave mode and frequency for subsequent experiments. A magnetostrictive transducer system was used to excite and detect the guided waves. The applicability of the proposed approach for detecting and locating wire breakages was demonstrated for a cable with 37 wires. The present ultrasonic guided wave method has been found to be very responsive to the number of brokenwires and is thus capable of detecting defects with varying sizes.

• Korean Journal of Comparative Education
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• v.24 no.5
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• pp.71-95
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• 2014

This is a pilot study of multifaceted longitudinal research project to explore educational experiences of students with multicultural family backgrounds in Korea. Especially for this pilot study, I selected three foreign-born immigrant youths and tried to explore how these youths describe constraints of their learning experience in different culture. The data for this study were mainly collected through qualitative research methods. For a better understanding of the research participants' perceptions in this study, narrative inquiry and series of semi-structured in-depth interviews were conducted for a period of four months which corresponds to one semester of school system in Korea. As a result, this study found that there is an urgent need to establish a systemic and developmentaly appropriate language education programs that ensure educating the language to the foreign-born immigrant youths because their academic achievement, interpersonal relationships, and future depend greatly on the fluency of Korean language. It was also found that it is necessary to take appropriate educational actions in supporting alternative schools where the foreign-born immigrant youths can fully and seriously considered as a whole person. Although this study has some limitations in examining every single aspect of the current state of education of students with multicultural backgrounds in Korea, it provides deep insight into some of their initial educational experiences and proposes several ways to improve these educational programs for them.

• Survey Research
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• v.12 no.2
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• pp.113-144
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• 2011

The purposes of the present study were (1) to identify the latent classes depending on youth employees' trajectories in job satisfaction and turnover intention and (2) to test the effects of person-job fit(major fit, education level fit, skill level fit) on job satisfaction and turnover intention using Youth Panel 2001. In order to estimate latent classes of job satisfaction and turnover intention changes simultaneously and study probabilities linking latent class membership in trajectory across the two variables, we applied dual trajectory model, an extension of semi-parametric group-based approach, Results showed that four latent classes were identified for job satisfaction, which were defined, based on the trajectory patterns, as increasing group, decreasing group, medium-level group, and high-level group. And, three latent classes estimated for turnover intention were defined as low-level group, maintaining group, and rapidly decreasing group. To test the effects of person-job fit variables, we added the variables as time-dependant variables to the unconditional latent class model. The effect of education level fit and skill level fit were found significant in the groups which are low in job satisfaction and have high in turnover intention. Findings from this study suggest the need to consider trajectory heterogeneity in the study of youth employees' job satisfaction and turnover intention to capture the dynamic dimension of overlap between the two constructs.

• The korean journal of orthodontics
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• v.30 no.6 s.83
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• pp.699-712
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• 2000

Reduced nasal breathing can influence the growth at)d development of facial structures. It nay have many causes, and enlarged adenoid is the most frequent one. To investigate the effects of adenoids to jaw growth, we must first understand the normal growth of adenoids and jaws, and the relationship between size of adenoids and the values lot the jaw variables. The purpose of this study is to present a more objective standard of nasopharyngeal size and jaw dimension at each bone age, by using Cervical Vertebrae Maturation Index(CYMI) of Hassel, from normal occlusion children aged 6 to 17. The results of this study suggests as follows : 1. At same bone age, female's chronologic age was about 2 year older than male. 2. There was a growth peak of nasopharyngeal(NP) height and depth between CVMI 1 to 2 in male, hut in female NP height and depth gradually increase through CVMI 1 to 6. 3. Relative airway of nasopharynx increases the most between CVMI 1 to 2 period in both gender 4. Among adenoid measurements, Ad2-related variables and upper pharynx, and among dentofacial measurements inter canine width in both arch, maxillary intermolar width and palatal depth had high correlation coefficient with adenoid percentage.

• Journal of Nutrition and Health
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• v.55 no.2
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• pp.263-277
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• 2022

Purpose: The present study examined the associations of Korean Food-based Index of Dietary Inflammatory Potential (FBDI) scores with the prevalence of diabetes and hemoglobin A1c (HbA1c) level of diabetes patients in Korean adults. Methods: The Korean Genome and Epidemiology Study (KoGES) Health Examinee baseline data, collected between 2004 and 2013 and followed up between 2012 and 2016, were used in our study. A total 56,391 participants including diabetes (n = 5,733) and non-diabetes (n = 50,658) were analyzed. The subjects were classified into quartiles of FBDI scores using the semi-quantitative food-frequency questionnaire developed for KoGES. The prevalence rate of diabetes under FBDI scores was assessed by Cox proportional risk models and the severity of the diabetes was analyzed by multiple regression analysis. Results: There were 775 incident cases of diabetes after a mean follow-up of 3.97 years. There was no statistically significant association between FBDI scores and incidence of diabetes. Among diabetes patients at baseline, FBDI scores were related to the risk of progression of diabetes which was represented by greater than 9% HbA1c (Q1 vs. Q4; odds ratio, 1.562 [95% confidence intervals, 1.13-2.15]; p for trend = 0.007). The stratified analysis showed a stronger association in females, irregular exercise group, and higher body mass index group. Conclusion: These results suggest that a pro-inflammatory diet is not associated with the incidence of diabetes but is related to the HbA1c level of diabetes patients. Thus, further longitudinal studies with longer periods are required to determine a relationship between dietary inflammatory index and diabetes in Korea.

• The korean journal of orthodontics
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• v.27 no.6 s.65
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• pp.891-904
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• 1997

Today's orthodontic treatment goals lie in functional esthetics, and the importance of the latter is increasing gradually in trend. Considering such, study on growth and development of soft as well as hard tissues becomes inevitable. Early studies emphasize mainly on skeletal analysis using cephalometric data. However, more recent studies report that maxillofacial soft tissue, which plays a critical role in determining facial esthetics, is influenced by underlying hard tissue, and yet close relationship between them was not noticed. Cephalometric x-rays were taken of 137 Korean boys and 106 girls with no systemic disease, fair developmental status and normal occlusion for two consecutive years; afterwards, soft tissue analysis, which was divided into four parts, facial form lip position & posture, nose, and thickness, was done to correlate them with general growth.

• Fisheries and Aquatic Sciences
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• v.20 no.11
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• pp.30.1-30.10
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• 2017

Small-scale fish farmers in developing countries are faced with challenges owing to their limited information on aquaculture management. Nile tilapia farmers in Teso North Sub-County recorded lower yields than expected in 2009 despite having been provided with required inputs. Water quality was suspected to be the key factor responsible for the low yields. This study sought to assess the effects of earthen pond water physico-chemical parameters on the growth of Nile tilapia in six earthen fish ponds under semi-intensive culture system in Teso North Sub-County. The study was longitudinal in nature with pond water and fish being the units of analysis. Systematic sampling was used to select five ponds while a control pond was purposively selected based on its previously high harvest. Four ponds were fed by surface flow and two by underground water. Each pond was fertilized and stocked with 900 fry of averagely 1.4 g and 4.4 cm. Physico-chemical parameters were measured in-situ using a multi-parameter probe. Sixty fish samples were randomly obtained from each pond fortnightly for four months using a 10 mm mesh size and measured, weighed and returned into the pond. Mean range of physico-chemical parameters were: dissolved oxygen (DO) 4.86-10.53 mg/l, temperature $24-26^{\circ}C$, pH 6.1-8.3, conductivity $35-87{\mu}S/cm$ and ammonia 0.01-0.3 mg/l. Temperature (p = 0.012) and conductivity (p = 0.0001) levels varied significantly between ponds. Overall Specific Growth Rate ranged between 1.8% (0.1692 g/day) and 3.8% (1.9 g/day). Ammonia, DO and pH in the ponds were within the optimal levels for growth of tilapia, while temperature and conductivity were below optimal levels. As temperature and DO increased, growth rate of tilapia increased. However, increase in conductivity, pH and ammonia decreased fish growth rate. Temperature and DO ranging between 27 and $30^{\circ}C$ and 5-23 mg/l, respectively, and SGR of 3.8%/day and above are recommended for higher productivity.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.629-636
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• 2022

Domestic eco-friendly vehicles currently account for 5.8% of the total registered vehicles in Korea. Hydrogen vehicles, one of the representative eco-friendly vehicles, have grown rapidly as they have been expanded to the market based on the government's policy to boost the hydrogen industry. Therefore, it is time to expand the safety review of hydrogen vehicles in various directions according to the increase in supply. In this study, the effect of internal heat damage was analyzed when a jet flame was generated by a hydrogen car in a road tunnel. It was simulated using Fluent, and the amount of jet flame injection was selected in consideration of the hydrogen tank capacity of commercial hydrogen vehicles for road tunnels. In addition, the study was conducted with the direction of the jet flame and the nozzle distance from the tunnel wall as variables. From the results, when the jet flame erupted in the road tunnel, high radiant heat emission of more than 20 kW/m² was generated in most areas within ±5 m in the longitudinal direction based on the vehicle (spray nozzle) and 5 to 7 m in the lateral direction based on the adjacent tunnel wall.

• Women's Health Nursing
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• v.5 no.1
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• pp.111-132
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• 1999

This correlational descriptive study sought to define the relationship between the experience of Sanhujori, Korean tradition non-professional postpartal care after delivery and abortion and present physical symptom distress of arthritis female who visited to outpatient clinic of rheumatic internal medicine at three hospital located in Seoul, Pusan, Chongju, Korea. Data from a convenience sample of 98 women who orally agreed to be respondent were collected from September 1, 1998 to October 31, 1998 for two months by way of interview with semi-structured questionnaire. Data analysis consisted of frequency, percentage, mean, S. D., Pearson Correlation Coefficient, t-test, ANOVA and Scheffe test as a post hoc by SPSS. The results of the study were as follows ; Mean age of participants as 52.8 years and mean number of children 3.3. Mean frequency of child birth was 3.1 times per woman, 67.4% of respondents had menopause, 57.0% did not have Sunhujori after abortion. The health status implies the subjective health status women perceived, which came from the three points of view of the present, comparative with other of same age and changed after delivery. The respondents of 76.1% perceived them as unhealthy and the main sites of physical symptom distress were upper & lower extremities including knee and hand 34.8%, shoulder 26.5%, waist 22.4%. Women perceived the etiology of the arthritis as 'did Sanhujori wrongly' 36.7%, 'aging process' 24.5%, 'stress' 16.3%, 'overwork' 15.3%, 'Immunocompromize' & 'physical constitution' 7.1% respectively, 'character' 3.1%, 'genetic' 2.0%, 'malnutrition' 1.0%. The mean period of Sanhujori after delivery was 20.4 at the first child and 18.1 at the second child. The higher frequency of child birth, the shorter period of Sanhujori. For the subjective evaluation of whether the women did Sanhujori well or not, the rate of 'did Sanhujori well' was the highest rank in the first child and the rate of 'did not particularly Sanhujori well' was the highest rank in the last child. There was a significant positive correlation between physical function disability and rheumatoid arthritis symptom at the level of 1% of significance statistically(r=.406). And a positive correlation between physical function disability and Sanhubyung symptom at the level of 5% of significance statistically(r=.224). There was a significant positive correlation among rheumatoid arthritis symptom, Sanhubyung symptom and menopause symptom at the level of 1%-5% of significance statistically. Most of all, the correlation between Sanhubyung symptom and menopause symptom was the higher than others. There was a negative correlation between the present physical symptom distress and experience of Sanhujori(r=.-130), however it was not significant statistically. However, there was a positive correlation between subjective health status and experience of Sanhujori at the level of 1% of significance statistically(r=.328). In conclusion, this finding reconfirmed the positive relationship between the perceived health status and experience of Sanhujori after delivery among women of arthritis. It provides a challenge to the professional care givers to study further on the effects of Sanhuiori after abortion or delivery on the physical symptom distress from the variouis aspects through the cross-sectional and longitudinal research. The strategy for the development of the appropriate intervention for primary prevention of sequele after childbirth and quality of care for desirable health outcomes for postpartal women with considering deeply on the relationship between women's health and postapartal care.