• Title/Summary/Keyword: a longitudinal study

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A longitudinal study on the development of English phonological awareness in preschool children (어린이집 유아의 영어 음운 인식 발달 종단 연구)

  • Chung, Hyunsong
    • Phonetics and Speech Sciences
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    • v.10 no.4
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    • pp.53-66
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    • 2018
  • This study investigated the development of English phonological awareness in preschool children based on a longitudinal study. It carried out a phonological matching task, mispronunciation task, articulation test, explicit phoneme awareness task, rhyme matching task, and initial-phoneme matching task for three-, four- and five-year-old children. A letter knowledge test was also added to the tests for the 5-year-old children. The results revealed that the development of phonological awareness follows a progression of syllable, then onset and rhyme, then phoneme. It was also revealed that language skills such as vocabulary, detection of mispronunciations, and articulation were partially related to the development of phoneme awareness. Finally, we also found that letter knowledge partially affected the children's development of phonological awareness.

Effect of Longitudinal Reinforcement Ratios and Axial Deformation on Frame Analysis in RC Columns (기둥의 철근비와 축변형량이 보 해석에 미치는 영향 연구)

  • 장원석;민창식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.477-482
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    • 2001
  • This paper is to study the effect of longitudinal reinforcement ratios and axial deformation on the frame analysis in reinforced concrete(RC) columns and to investigate the effect of confined concrete core, the length-width ratio and longitudinal steel ratios on frame analysis in Concrete-Filled steel Tubular(CFT) columns. An equation if derived to evaluate the modulus of elasticity for core concrete. The 34 reference data have been collected for the purpose and are processed by the mean of a multiple regression analysis technique. The equation and longitudinal reinforcement ratios was applied to RC columns for structural analysis. Then, the difference of beam moment was identified. In general, the results of analysis was indicated reasonable differences in beam moment, in case of longitudinal reinforcement ratios applied to RC columns when compared with the plain concrete columns. In CFT columns the equation was also applied in order to the effect of confined concrete core on structural analysis. Beam moment was increased as volumetric ratio of lateral steel was decreased. The effect of longitudinal steel ratios was investigated in CFT columns and was confirmed beam moment variety. The result was appeared reasonable difference in beam moment as longitudinal steel was increased.

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The Experimental Study of the End-to-side Microarterial Anastomosis with the Longitudinal Slit and the Triangular Flap (고전적 및 삼각조각 기법을 이용한 단-측면 미세동맥 접합술의 실험적 연구)

  • Lee, Jun-Mo;Lee, Gang-Wook;Lee, Dong-Geun
    • Archives of Reconstructive Microsurgery
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    • v.1 no.1
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    • pp.51-55
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    • 1992
  • Problems of composite tissue transfer commonly arise when a single indispensable recipient vessel receives the graft vssel, and the graft vessel must be sutured in end-to-side fashion so as not todisturb the vascularity of the recipient vessel. The triangular flap in the recipient vessel wall gives an intact endothelial surface when the flow of blood stream is presented and may reduce the chance of anastomosis. We selected mature Wistar rats weighing over 450 grams to compare the conventional longitudinal slit from the triangular flap in the recipient carotid artery over bloood pressure and blood flow when the donor carotid artery was anastomosed in end-to-side fashion. In 30 minutes after anastomosis, maximum blood pressure measured in the donor carotid arterial side when the recipient arterial wall was fasioned with the longitudinal slit was recorded 114 mmHg and with the triangular flap 100mmHg. Minimum blood pressure with the longitudinal slit was 98mmHg and with the triangular flap 88mmHg. The amount of blood collected for 30 seconds in the conventional longitudinal slit was 1.18mg and in the triangular flap 0.78mg. Histology study in 30 minutes, the conventional longitudinal slit demonstrated the more hemorrhagic features around the suture material compared to that of the triangular. flap and, in the 7th day, the conventional longitudinal slit demonstrated the more prominent granulomatous reactions and vascular proliferations around the suture material compared to that of the triangular flap.

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Development of a Longitudinal Control Algorithm based on V2V Communication for Ensuring Takeover Time of Autonomous Vehicle (자율주행 자동차의 제어권 전환 시간 확보를 위한 차간 통신 기반 종방향 제어 알고리즘 개발)

  • Lee, Hyewon;Song, Taejun;Yoon, Youngmin;Oh, Kwangseok;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.12 no.1
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    • pp.15-25
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    • 2020
  • This paper presents a longitudinal control algorithm for ensuring takeover time of autonomous vehicle using V2V communication. In the autonomous driving of more than level 3, autonomous systems should control the vehicles by itself partially. However if the driver's intervention is required for functional safety, the driver should take over the control reasonably. Autonomous driving system has to be designed so that drivers can take over the control from autonomous vehicle reasonably for driving safety. In this study, control algorithm considering takeover time has been developed based on computation method of takeover time. Takeover time is analysed by conditions of longitudinal velocity of preceding vehicle in time-velocity plane. In addition, desired clearance is derived based on takeover time. The performance evaluation of the proposed algorithm in this study was conducted using 3D vehicle model with actual driving data in Matlab/Simulink environment. The results of the performance evaluation show that the longitudinal control algorithm can control while securing takeover time reasonably.

Influence of Longitudinal Arch of Foot on the Strength and Muscle Activity of the Abductor Hallucis in Subjects with and without Navicular Drop Sign

  • Jeon, In-Cheol
    • The Journal of Korean Physical Therapy
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    • v.31 no.4
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    • pp.222-227
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    • 2019
  • Purpose: This study examined the influence of longitudinal arch on the strength and muscle activity of the abductor hallucis in the standing position in subjects with and without navicular drop signs. Methods: A sample of 34 subjects with and without navicular drop signs between 22 and 28 years of age were enrolled in this study. The strength and muscle activity of the abductor hallucis was measured using a tensiometer. The Smart KEMA System and electromyography device was used on the subjects with and without navicular drop signs. Two groups were classified using the navicular drop test to identify the longitudinal arch of the foot. The strength of the abductor hallucis was evaluated in standing, both with and without an external arch support condition. The two-way mixed ANOVA was used. The level of statistical significance was set to ${\alpha}=0.05$. Results: The strength and muscle activity of the abductor hallucis in standing was significantly higher with external arch support than that without the external arch support in the group with navicular drop signs. There was no significant difference in the abductor hallucis strength and muscle activity with and without external arch support in the subjects without navicular drop signs. Conclusions: The strength and muscle activity of the abductor hallucis in standing can be influenced by the external arch support in the group with navicular drop signs. The strength measurement of the abductor hallucis in standing should be separately performed in conditions with and without longitudinal arch of foot.

A Study on Compact Section Requirements for Plate Girder Web Panels with Longitudinal Stiffeners (수평보강재가 설치된 플레이트거더 복부판의 조밀기준에 관한 연구)

  • Lee, Myung Soo;Lee, Doo Sung;Lee, Sung Chul
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6A
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    • pp.503-512
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    • 2010
  • In AASHTO LRFD (2007), a compact section is defined as a section in which no premature failure caused by local buckling of web and flange plate or later buckling occurs before the section reaches the plastic moment, Mp. The current AASHTO LRFD (2007) provides the compact section requirement by limiting the web slenderness only for webs without longitudinal stiffeners. The role of longitudinal stiffener is to increase the web buckling strength caused flexure. Although a web does not satisfy the compactness requirement without longitudinal stiffeners, the web buckling can be prevented by use of valid longitudinal stiffeners. Therefore, the web may be able to reach the plastic moment. However, the reason why a longitudinal stiffener may not be used to satisfy compactness requirement is not cleary explained in AASHTO LRFD (2007). In this study, the buckling and ultimate strength behaviors of stiffened webs subjected to bending are investigated through the linear buckling and nonlinear finite element analysis. It is found that steel plate girders having webs that do not satisfy the compactness requirement are able to reach the plastic moment if the longitudinal stiffeners have sufficient rigidities and are properly located. From a nonlinear regression analysis of the results, a new compactness requirement is suggested for webs stiffened with one longitudinal stiffener.

Analysis of 'Better Class' Characteristics and Patterns from College Lecture Evaluation by Longitudinal Big Data

  • Nam, Min-Woo;Cho, Eun-Soon
    • International Journal of Contents
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    • v.15 no.3
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    • pp.7-12
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    • 2019
  • The purpose of this study was to analyze characteristics and patterns of 'better class' by using the longitudinal text mining big data analysis technique from subjective lecture evaluation comments. First, this study classified upper 30% classes to deduce certain characteristics and patterns from every five-year subjective text data for 10 years. A total of 47,177courses (100%) from spring semester 2005 to fall semester 2014 were analyzed from a university at a metropolitan city in the mid area of South Korea. This study extracted meaningful words such as good, course, professor, appreciation, lecture, interesting, useful, know, easy, improvement, progress, teaching material, passion, and concern from the order of frequency 2005-2009. The other set of words were class, appreciation, professor, good, course, interesting, understanding, useful, help, student, effort, thinking, not difficult, explanation, lecture, hard, pleasant, easy, study, examination, like, various, fun, and knowledge 2010-2014. This study suggests that the characteristics and patterns of 'better class' at college, should be analyzed according to different academic code such as liberal arts, fine arts, social science, engineering, math and science, and etc.

Development and Operation of Longitudinal Integrated Clerkship Programs in Overseas Medical Schools (외국 의과대학에서의 장기추적통합임상실습 개발과 운영사례)

  • Yeo, Sanghee
    • Korean Medical Education Review
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    • v.20 no.1
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    • pp.6-14
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    • 2018
  • In recent years, Korean medical schools have shown a growing interest in the longitudinal integrated clerkship (LIC) as a means of improving clinical education. Some overseas medical schools have tried the LIC since the 1970s. In the 1990s, several universities in the United States, Canada, and Australia introduced LICs. A variety of studies have confirmed positive results of the LIC. Traditional block-rotation is a discipline-based, inpatient-centered practice. Instead, under the LIC system, a medical student responsible for a panel of longitudinal patients observes developments of their diseases, serving several departments simultaneously. Overseas medical schools have different LIC models depending on their affiliate hospitals' sizes and characteristics. The purpose of this study is to introduce LIC practices in Harvard Medical School and University of California San Francisco, which could be applied by Korean medical schools. This paper also aims to find out the strategies that have been able to help the two US medical schools implement the LIC successfully.

Body Image Dissatisfaction and Self-esteem among Korean Pre- and Early Adolescent Girls and Boys: A Five-year Longitudinal Panel Study (후기 아동기 및 초기 청소년의 신체상불만족과 자존감: 종단적 패널 연구)

  • Park, Woochul
    • Human Ecology Research
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    • v.58 no.2
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    • pp.163-176
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    • 2020
  • Longitudinal studies have shown mixed findings on the association between body image dissatisfaction and self-esteem among adolescents. This study examined the longitudinal, reciprocal influences between body image dissatisfaction and self-esteem among Korean pre- and early adolescents by using nationally representative longitudinal panel data from the Korean Youth Panel Study (KYPS). Analyses based on 2,230 participants indicated that girls' body image dissatisfaction was significantly higher than boys'. The trajectory of body image dissatisfaction increased sharply during pre- and early adolescence, but stabilized afterwards for both boys and girls. Self-esteem deteriorated rapidly initially, but began to recover as adolescent girls and boys matured. Structural equation modeling showed that reciprocal influences between body image dissatisfaction and self-esteem were detected for boys. Body image dissatisfaction among girls predicted self-esteem during the entire period, while the opposite direction from self-esteem to body image dissatisfaction emerged two years later. The present study found that, during pre- and early adolescence, body image dissatisfaction and self-esteem develop in a circular fashion by forming a vicious cycle. Implications for the development of intervention and prevention programs are discussed in consideration of age and gender.

The Influence of Parenting and Peer Relationship on the Development of Child's Self-Concept : A Longitudinal Study (부모의 양육행동 및 또래관계가 아동의 자아개념 발달에 미치는 영향에 관한 종단적 연구)

  • Lee, Sarah;Park, Seong Yeon
    • Korean Journal of Child Studies
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    • v.22 no.4
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    • pp.17-32
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    • 2001
  • The purpose of this study was to explore the developmental patterns of self-concept of pre-adolescents and adolescents by using the longitudinal data originated by the Korean Institute for Research in the Behavioral Sciences (KIRBS). Specifically, using Structural Equation Modeling (SEM), the effects of parents and peer groups on the stability and change of self-concept were examined across a 9-year-period. The subjects were 62 children(29 boys and 33 girls) from the KIRBS longitudinal data. The results showed that, peer relationships revealed consistent effects on children's self-concept from pre-adolescence to mid-adolescence. In particular, this influence was most evident at 7 years of age and at 16 years of age. However, parental influence was almost non-existent for 7-year-olds, equivalent to peer relationships for 10-year-olds, and decreased for 16-year-olds. On the whole, parental and peer influence on self-concept gradually decrease in adolescence. Nevertheless, parental and peer influence continue to maintain a certain level of influence from childhood to adolescence. This study provides an understanding of developmental change and stability in the self-concept of Korean adolescents.

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