• Korean Journal of Health Education and Promotion
• /
• v.11 no.1
• /
• pp.70-84
• /
• 1994

On the basis of the study intended to research by cross-sectional study keeped pace with semi-longitudinal study the growth accelerating phenomena that MGA(Maximum Growth Age) in teenager's body height. The duration of study is from Oct. 1st. 1991 to September 30 1992 and the data are analysed through computer. The body height and MGA of Koreans who had been for during the period from 1898 to 1973 proved transition of the growth accelerating phenomena by research data reported between 1913 and 1990. The results are as follows: 1. Maximum Growth Age The MGA's in body height of male are respectively the age 15.024 in 1913, 14.28 in 1940, 13.65 in 1959, 13.86 in 1967, 12.52 in 1983, 11.39 in 1987, 12.36 in 1990, while those of female are the age of 12.0 in 1940, 12.36 in 1959, 10.45 in 1969, 11.15 in 1985, 10.27 in 1988, 10.23 in 1990 ; these data show that the MGA of the Korean has been getting younger. 2. The correlation of the MGA's in body height are as below ; Male ; r = -0.448(p<0.01) Female ; r = -0.404(p<0.05) 3. The equation of linear regression of MGA's in body height are as below ; Male ; Y(MGA) = -0.0316X(the year)+75.297 Female ; Y(MGA) = -0.035X(the year)+79.986 4. The MGA's in body height are shown in Table 3. 5. From the transition of the growth accelerating phenomena, we can compute the fact that the MGA's has been getting younger by 0.3 year per 10 years. 6. The future growth accelerating phenomena in body height, the MGA's of male are respectively the age 12.25 in 1995, 12.09 in 2000, 11.94 in 2005, 11.78 in 2010, while those of female are the age of 10.16 in 1995, 9.98 in 2000, 9.81 in 2005, 9.64 in 2010, these data show that the MGA of female are more younger than that of male.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.31 no.3
• /
• pp.154-160
• /
• 2020

Objectives: It remains unclear whether methylphenidate (MPH) has yadverse effects on growth in children. This study aimed to investigate the association of MPH with serum biological markers of growth in children with attention-deficit/hyperactivity disorder (ADHD). Methods: The present study included 103 children with ADHD (64 drug-naive children, 39 MPH-treated children) and 112 control subjects. Children with ADHD were diagnosed on the basis of a semi-structured interview. Levels of biochemical markers of growth, including insulin-like growth factor-I, thyroid stimulating hormone (TSH), free T₄, calcium, phosphorus, alkaline phosphatase, vitamin D, hemoglobin, total protein, albumin, total cholesterol, and hematocrit were measured in these individuals. Results: Except in case of TSH, no intergroup differences were found in the levels of the growth markers. The levels of TSH were found to be lower in the MPH-treated boys with ADHD than in the drug-naive and control groups (p<0.05), although the levels of TSH in all the groups were within normal limits. Conclusion: In this cross-sectional study, no significant association was found between MPH and growth markers. This calls for the need to carry out prospective longitudinal research studies in the future that investigate the effect of MPH on the growth trajectory in children.

• Korean Journal of Social Welfare Studies
• /
• v.41 no.1
• /
• pp.119-144
• /
• 2010

This study advances the knowledge of developmental patterns in affiliation with delinquent peers and delinquency during adolescence; data were obtained from waves 1-5 (2003-2007) of the Korea Youth Panel Survey. Semi-parametric group-based modeling (SGM) identified 3 affiliative trajectories of delinquent peers from age 13 to 16: rarely or never, persistently affiliative, and declining groups; and five developmental trajectories of delinquency: non-offending, late onset, low-level continuous, desisting, and chronic groups. A joint trajectory analysis predicted the membership of delinquency trajectories conditional on delinquent peer trajectories. Persistently affiliative group was more likely than others to follow chronic trajectory of delinquency; the rarely or never affiliative group was more likely to be non-offending. This study may help reconcile different theoretical models such as influence, selection, and enhancement models with respect to the role of delinquent peers in delinquency. The distinct theoretical models are equally valid, albeit each model pertains to a specific aspect of longitudinal patterns of affiliation with delinquent peers. Implications of this study for youth welfare were discussed to reduce increased risks for both affiliation with delinquent peers and delinquency.

• Fire Science and Engineering
• /
• v.23 no.3
• /
• pp.79-84
• /
• 2009

The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75m/s and 2.5m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

• Phonetics and Speech Sciences
• /
• v.12 no.2
• /
• pp.63-72
• /
• 2020

This study aims to develop a video-based smart utterance deep analyser (SUDA) application that analyzes semiautomatically the utterances that child and mother produce during interactions over time. SUDA runs on the platform of Android, iPhones, and tablet PCs, and allows video recording and uploading to server. In this device, user modes are divided into three modes: expert mode, general mode and manager mode. In the expert mode which is useful for speech and language evaluation, the subject's utterances are analyzed semi-automatically by measuring speech and language factors such as disfluency, morpheme, syllable, word, articulation rate and response time, etc. In the general mode, the outcome of utterance analysis is provided in a graph form, and the manger mode is accessed only to the administrator controlling the entire system, such as utterance analysis and video deletion. SUDA helps to reduce clinicians' and researchers' work burden by saving time for utterance analysis. It also helps parents to receive detailed information about speech and language development of their child easily. Further, this device will contribute to building a big longitudinal data enough to explore predictors of stuttering recovery and persistence.

• The korean journal of orthodontics
• /
• v.26 no.4
• /
• pp.325-340
• /
• 1996

Along with traditional goal of 'straightening teeth', today's orthodontics put more and more emphasis on facial esthetics. Naturally, the importance of soft tissue, which dictates one's facial form, is noticed. There have been many cephalometric studies on growth of hard tissue ; however, only a few on that of soft tissue. In Korea, various methods of sampling, measuring and analysing were used to study soft tissue changes, and yet, soft tissue changes along with process of normal growth have not been studied. The author carried out this study as a part of semi-longitudinal study on craniofacial growth and development of Korean children from ages of six to seventeen. 409 boys and 436 girls who'd had no systemic disease for the last three years and shown normal developmental and occlusal status were chosen as subjects. Cephalometric X-rays were taken of each subject, and facial form, lip position & form, nose form, and lip thickness were measured. Mean values and standard deviations were calculated according to age and gender, and figures and tables were drawn accordingly. The following results were obtained: 1. In respect to facial form, boys showed growth for longer period compared to girls. Also, lower face showed higher growth rate than upper face. 2. There was not much change in thickness of upper and lower lips with age; however, they appeared more prominent compared to caucasian children. 3. Nose grew horizontally with age. 4. Horizontal thickness of lower face increased with age, and upper lip thickness at nose base[A-Sn(FH)] showed more growth than anywhere else.

• The korean journal of orthodontics
• /
• v.26 no.3
• /
• pp.225-239
• /
• 1996

This study was carried out as a part of the semi-longitudinal study on growth and development of Korean children, with purpose of observing the growth change in arch form., 736 pairs, of study models were taken for 3 years. Mesio-distal diameter of each tooth, intercanine width, intermolar width, canine arch depth, molar arch depth and arch perimeters were measured. Afterwards, mean value and each standard deviation of each age group and each gender were obtained, and corresponding graphs were drawn. The following conclusions were obtained : 1. Mesio-distal diameters of maxillary central incisor, maxillary 2nd molar, mandibular canine, and mandibular 2nd molar showed statistical difierences between boys and girls. 2. Intercanine width shows a gradual increase until age of 11. 3. Intermolar width in maxilla shows continuous increase, and the tendency of increase is more apparent between age of 9 and 14. In mandible, various pattern was shown until age of 9, and after, a slight increase. 4. Canine arch depth shows the increasing tendency until age of 13 in maxilla and 11 in mandible. 5. Molar arch depth shows the pattern of increase until age of 10 in male and 9 in female, which is more apparent in maxilla. After age of 9 or 10,dereasing pattrn was significantly shown until age of 15 in maxilla and age of 12 in mandible. 6. Arch perimeters in maxilla and mandible showed gradual increase until age of 10, and the tendency of increase was more apparent in maxilla; however, between the age of 10 and 14, arch perimeters of maxilla and mandible showed gradual decrease which was more apparent in mandible.

• The korean journal of orthodontics
• /
• v.29 no.1 s.72
• /
• pp.51-72
• /
• 1999

In orthodontic field, it is very important to understand the normal growth. Such an understanding can be derived from observation of normal growth in various samples from childhood to adulthood, and this builds a foundation from which growth abnormality or variation can be defined. Thus, a broad data collection of normal children, as well as basic study reviewing such data become necessary. The relationship between the mean values of cephalometric measurements in Growth and Development was studied among the groups(boys and girls) of Korean chidren from the ages 6-years to 16-years. 220 boys 170 girls were chosen as subjects : Cephalometric X-ray were taken for 3 years and hard tissue analysis on McNamara and Ricketts Analysis which was divided into measurements of 5 parts(Cranial base, Cranial base and Maxilla & Mandible, Maxilla and Mandible, Mandible, Dental measurements). The relationship of craniofacial growth was studied. The following conclusions were obtained: 1. There were statistically significant differences in anterior cranial base between the two sexes of 14 and 15-year grouips. 2. In comparison of growth amounts among different age groups, statistically singnificant difference in Posterior facial height exhisted among $10\~11,\;12\~13\;and\;14\~15$ year-old interval groups. This pattern increased with aging. 3. Na perpendicular to A showed earlier growth peak in females(11-12years) than males(12-13years). When horizontal measurements of point A and Pogonion are compared, mandibular growth appeared to be greater. 4. Maximum growth peak of cranial base and mandible was earlier in females (11-12years) than males(13-14 years). 5. Upper central incisor flared out with aging, and there were increases in lower incisor to A-Pg, and lower incisor inclination There was significant difference between the two sexes in 10-year-old group.

• Geotechnical Engineering
• /
• v.13 no.6
• /
• pp.107-122
• /
• 1997

This paper presents a ground surface settlement prediction method for shield tunneling in cohesive soils. In order to develop the method, a parametric study on shield tunneling was performed by using a threetimensional elasto-plastic finite element analysis, which can simulate the construction procedure. By using the results of the finite element analysis, the ground movement mechanism was investigated and a base which relates the ground surface settlement and iuluencing factors was formed. The data base was then used to formulate semi -empirical equations for both surface settlement ratio above tunnel face and imflection point by means of a regression analysis. Furthermore, a prediction method for transverse and longitudinal surface settlement profiles was suggested by using the leveloped equations in conjunction with the normal probability curve. Effectiveness of the developed method was illustrated by comparing settlement profiles obtained by using the developed method with the results of finite element analysis and measured data. Based on the comparison, it was concluded that the developed method can be effectively rosed for practical applications at least within the conditions investigated.

• Journal of the Korea Concrete Institute
• /
• v.14 no.2
• /
• pp.231-238
• /
• 2002

Dry shrinkage md temperature change cause to develope concrete bridge decks on main girders have initial unidirectional cracks in longitudinal or transverse direction. As they receive traffic loads, the crack gradually propagate in different directions depending on the concrete dimension and reinforcement ratio. Since existing equations that predict crack width are mostly based on the one directional bond-slip theory, it is difficult to determine the actual crack width of a bridge deck with varying the spacing of rebar or strengthening material and to estimate the improvement rate in serviceability of the strengthened bridge deck. In this study, crack propagation mechanism is identified based on the test results and a new crack prediction equation is proposed for evaluation of serviceability. Although more accurate results are derived using the proposed equation, the extent of error is increased as the strain of the rebar or the strengthening material increases after the yielding of rebar Therefore, further research is required to better predict the crack width after the rebar yields under fatigue loading condition.