• Imaging Science in Dentistry
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• v.44 no.3
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• pp.185-191
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• 2014

Purpose: This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. Materials and Methods: A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. Results: The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. Conclusion: The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.63-70
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• 1996

This paper is concerned with a chronological analysis of the simple limb movement and the performance of a selective response for Korean adults. The cybernetical control number(C.C.No) tester is used to perform the experiment for 103 males and 96 females aged from 20s to above 60s. For the selective response ecperiment, judgement speed has decreased with age. The judgement speed was slowed down more rapidly with age for female than for male. Both the limb movement and the judgement speed showed significantly different trends according to age groups. Especially, it was shown that simple limb movement decreased beginning with 50s for male and 40s for female. It is expected that the results can be applied to the job design of aged people.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.262-268
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• 2023

It is necessary to investigate how age or gender affects visual perception and social skills in late adolescence. A study on the relevance of visual perception in late adolescence, a period that requires social adaptation through the development of social functions, is necessary. The purpose of this study is to investigate the relationship between visual perception and social skills in adolescence. Visual perception and social skill were evaluated for 18-24-year-olds, who are in late adolescence, and were analyzed for gender differences and correlations with chronological age. This study found that there was a difference in visual perceptual function according to gender in late adolescence, and it was significantly higher in men. There was no significant difference in social skills according to gender. However, there was a significantly positive correlation between chronological age and visual perception, but there was no correlation with social skills. These findings provide novel information regarding the developmental course of visual perception and social skill in late adolescence.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.78-83
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• 2007

The purpose of present study was to investigate the characteristics of disfluency between the Korean-English bilingual and Korean monolingual children, matched by their chronological age with the bilingual children. Twenty-eight children, 14 bilingual children and 14 monolingual children participated in this study. The experimental tasks consisted of the play situation and the task situation. The conclusion is (a) The score of total disfluency of the bilingual was significantly higher than that of the monolingual. The score of normal disfluency of the bilingual was significantly higher than that of the monolingual. The most frequent type is Interjection in both groups. All shows higher score in the task situation than the play situation. The bilingual children have quantitative and qualitative differences in disfluency score and types from the monolingual. (b) The bilingual were divided into two groups such as 6 Korean-dominant bilingual and 8 English-dominant bilingual. All shows more disfluency in their non-dominant language. The most frequent type is Interjection in both groups. (c) The higher the chronological age and the expressive language test score is, the lower the disfluency score is. The earlier the exposure age to the 2nd language is, the higher the disfluency score is. There is no correlation between resident month at foreign country and the disfluency.

• Journal of Gastric Cancer
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• v.1 no.3
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• pp.161-167
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• 2001

Purpose: Although gastric carcinomas occur throughout the world and the incidence is on the decrease, they remain the most common type of carcinoma in Korea. Significant advancements in the diagnostics and the surgical treatment of gastric carcinomas have been achieved during the last three decades. The present retrospective study was undertaken to investigate the chronological changes in the clinical features, including clinicopathological findings, operative treatment, and prognosis of gastric carcinomas. Materials and Methods: A total of 1973 patients with a primary gastric adenocarcinoma who had been treated surgically during the period from 1983 to 1998 at the Department of Surgery, Korea University College of Medicine, were divided into two groups to evaluate chronological changes: 1007 patients had been treated during the period from 1983 to 1992 (early period) and 966 patients during the period from 1993 to 1998 (late period). Chronological changes in age, sex, ratio of early gastric cancer (EGC), and resectability were analyzed in all 1973 cases. For the 1755 resected cases, we also studied the chronological changes in the clinicopathological and treatment factors between the early-period (n=894) and the late-period (n=867) groups. Results: There were significant differences between the two periods with regard to age and ratio of EGC: EGC was more frequent in the late period. Univariate analysis of resected cases showed that gross type, tumor size, depth of invasion, UICC stage, and histological type were statistically significant. The analysis of the treatment factors revealed that total gastrectomies and extended lymphadenectomies were more frequent during the late period. The number of lymph nodes dissected was $26.0\pm12.7$ in the early period and $33.4\pm14.1$ in the late period (p<0.01). The 5-year survival rate in all cases was $51.4\%$ in the early period and $55.9\%$ in the late period. The stage-related survival rates (UICC 4th Ed., 1987) in the early vs. the late periods were $92.9\%\;vs.\;95.5\%$ in stage IA, $82.1\%\;vs.\;91.1\%$ in stage IB, $76.5\%\;vs.\;73.1\%$ in stage II, $46.5\%\;vs.\;52.1\%$ in stage IIIA, $14.5\%\;vs.\;33.6\%$ in stage IIIB, and $2.8\%\;vs.\;8.8\%$ in stage IV. There was a statistically significant difference in survival between stage IIIB and IV. Conclusion: These results suggest that the differences in the clinicopathological findings are related primarily to the increased number of early gastric cancer cases in the late period and that the improved survival noted during the late period for in stage IIIB and IV cancers might be related to extended surgery.

• Phonetics and Speech Sciences
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• v.11 no.4
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• pp.9-18
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• 2019

This study aimed to investigate the correlation between speaker's chronological age (CA) and perceived age (PA) and to specify the effect of pitch and speech rate as acoustic cue on judging age, using perceptual testing and acoustic analysis. Three tasks were conducted to identify the degree of listener's accuracy about age estimation. Three perception tasks were conducted to measure the accuracy of 80 Korean listeners when presented with different types of speech. In all the tasks, participants listened to speech samples and gave their estimate of the speaker's age in figures. It was found that Korean listeners are able to gauge the age of a speaker fairly precisely. CA and mean PA were positively correlated in all three tasks. It is clear that the amount and type of information included in the voice samples affected the accuracy of a listener's judgement. Moreover, the result revealed that listeners make use of acoustic information such as pitch and speech rate to estimate speaker's age.

• Imaging Science in Dentistry
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• v.43 no.1
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• pp.1-6
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• 2013

Purpose: This study investigated the possible correlation between the mineralization of the second molars and the chronological age of a sample population of the state of Paraiba, Brazil. Materials and Methods: One thousand eight hundred fifty-four digitized panoramic images using a scanner of a private dental radiology service were obtained in six months. Of these, 457 were selected from patients aged 4.6 to 16 years who met certain criteria. The images were assessed twice by a radiologist with 5 years experience. A minimum interval of 30 days between the evaluations of the same patient was established. To analyze the relationship between chronological age, calcification level proposed by Demirjian et al in 1973, gender, and tooth, a multiple linear regression model was adjusted, taking age as the response variable (p<0.05). Results: The gender and calcification level were significantly correlated with the age of the patients (p<0.05). There was a significant difference between the average age of the patients' upper teeth compared to the lower ones in both genders (p<0.05). The dental development occurred earlier in female individuals than in male ones, and there was no significant difference between the right and left second permanent molars. Conclusion: It was observed that ethnic variables are related to certain parameters of age and sex identification in the Brazilian population, providing important information for forensic evaluations.

• Journal of Korean Physical Therapy Science
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• v.3 no.1
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• pp.835-841
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• 1996

The purpose of this study is to investigate the relationship between the development of laterality and bilateral motor abilities measured with respect to various rhythm movements in upper extremity of mentally retared children. The development of laterality was measured by a survey of dominace-hand. The bilateral motor abilities were assessed by means of a tentative rhythm beat test of hands. One hundred sixty eighty subjects with special education needs shose age ranged from 7 to 18 years old were used for an experimental group. Fity nine normal children whose age ranged from 3 to 6 years old were also chosen as a control group. The major findings were a follows: 1. The development of lateral dominace-hand in mentally retared children differed from that of normal subjects with as increase in chronological age; the degree of the attainment of lateral dominance - hand was 75 percest of the mean level of the normal children. Though normal children establish a dominance - hand by ths age of years old, meatally retarded children are likely to show 57 percent of normal development at the age of 7 through 9 years old and 65 percent of normal development at the age of 16 through 18 years old. 2. A greater delay in mentally retarded was found through a rhythm test which was development to assess bilateral motor abilities in upper extremity. A closser relationship betwin chronological age and the development of bilateral motor abilities in mentally retared children was found. 3. In view of these findings, it was indicated that bilateral motor abilities of the retarded and non-retarded children were significantly correlated to the acqusition of dominance-hand.

• The Journal of Korean Medicine
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• v.35 no.1
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• pp.88-98
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• 2014

Objectives: The purpose of this study is to investigate the relationship between bone age, chronological age, anthropometric parameters, and diagnosed pulse rate on child-adolescence's growth according to sex and the revelation of secondary sexual characteristics. Methods: Growth-concerned 44 children and adolescence (from 6 to 16 years) were analyzed in retrospective study. They visited Korean Medical Clinic in Suwon, Korea from January 2012 to October 2013. Individual bone age (BA), chronological age (CA), Risser sign, anthropometric parameters, and pulse rate were measured. The correlations of each variable were done by Pearson analysis, Spearman analysis and Regression analysis. Results: 1. The female group was shown to have stronger negative correlation between pulse rate and BA, CA than the male group. In gender analysis, the female group showed negative correlation between weight and pulse rate. 2. In a further analysis according to the revelation of secondary sexual characteristics, the group of child-adolescent without secondary sexual characteristics was shown to have stronger negative correlation between pulse rate and BA, CA than the group with secondary sexual characteristics. The height percentile and pulse rate were negative correlation in secondary sexual character being. 3. The Risser sign and pulse rate were not correlated in this study. Conclusions: These findings suggested that a regular and continual measurement of pulse rate is effective in estimating potential for growth in child-adolescent group.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.1
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• pp.10-20
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• 2019

Individual dental age is used as an index of chronological age estimation and is an important indicator of the child's growth stage. Dental age does change greatly over time, but it changes constantly. And updating information about this change is important. The purpose of this study was to provide information about tooth eruption stage using diagnostic model analysis and to investigate tooth eruption sequence and estimate chronological age based on this information. Tooth eruption stages were measured on a diagnostic model from 488 patients in 5 - 13 year old children. Based on the information on eruption stage, eruption sequence in maxilla was first permanent molar, central incisor, lateral incisor, first premolar, canine, second premolar and second permanent molar. Eruption sequence in mandible was first permanent molar, central incisor, lateral incisor, canine, first premolar, second premolar and second permanent molar. There were significant differences between males and females in the eruption stage of canine, first and second premolar, and second molar at several ages. The chronological age of male and female was estimated by the coefficient of determination of 0.816, 0.826 respectively.