• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.173-174
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• 2006

Understanding chondrocyte behavior inside complex, three-dimensional environments with controlled patterning of geometrical factors would provide significant insights into the basic biology of tissue regenerations. One of the fundamental limitations in studying such behavior has been the inability to fabricate controlled 3D structures. To overcome this problem, we have developed a three-dimensional microfabrication system. This system allows fabrication of predesigned internal architectures and pore size by stacking up the photopolymerized materials. Photopolymer SL5180 was used as the material for 3D scaffolds. The results demonstrate that controllable and reproducible inner-architecture can be fabricated. Chondrocytes harvested from human nasal septum were cultured in two kinds of 3D scaffolds to observe cell adhesion behavior. Such 3D scaffolds might provide effective key factors to study cell behavior in complex environments and could eventually lead to optimum design of scaffolds in various tissue regenerations such as cartilage, bone, etc. in a near future.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1086-1092
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• 2000

To realize a visual servo control of slender manipulators, two problems to be solved are analysed. The stability problem on so-called noncolocation control and the infinite order problem of the real Jacobian matrix caused by the elastic deformation are discussed. By considering the dynamic relations between rigid and elastic modes, a Jacobian operator is derived and the physical meaning is also explained. Then, for practical control, a simple control scheme using an approximate Jacobian is proposed and its stable conditions are proven by means of the $L_$2$ stability theory. The scheme is structurally similar to the conventional PD control laws, but external sensors(e. g. visual sensor) are used for positioning and internal sensors for damping. A good performance is obtained via control experiments of a slender two link manipulator.

• Computers and Concrete
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• v.23 no.3
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• pp.171-188
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• 2019

This study proposed a new and efficient 2D damage-plasticity model within the framework of Isogeometric analysis (IGA) for the geometrically nonlinear damage analysis of concrete. Since concrete exhibits complicated material properties, two internal variables are introduced to measure the hardening/softening behavior of concrete in tension and compression, and an implicit gradient-enhanced formulation is adopted to restore the well-posedness of the boundary value problem. The numerical results calculated by the model is compared with the experimental data of three benchmark problems of plain concrete (three-point and four-point bending single-notched beams and four-point bending double-notched beam) to illustrate the geometrical flexibility, accuracy, and robustness of the proposed approach. In addition, the influence of the characteristic length on the numerical results of each problem is investigated.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.7-19
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• 2002

This paper presents the results of an investigation on the effect of foundation stiffness on the performance of soil-reinforced segmental retaining walls (SRWalls). Laboratory model tests were performed using a reduced-scale physical model to capture the fundamentals of the manner in which the foundation stiffness affects the behavior of SRWalls. A series of finite-element analyses were additionally performed on a prototype wall in order to supplement the findings from the model tests and to examine full-scale behavior of SRWalls encountered in the field. The results of the present investigation indicate that lateral wall displacements significantly increase with the decrease of the foundation stiffness. Also revealed is that the increase in wall displacements is likely to be caused by the rigid body movement of the reinforced soil mass with negligible internal deformation within the reinforced soil mass. The findings from this study support the current design approaches, in which the problem concerning the foundation condition are treated in the frame work of the external stability rather than the internal stability. The implications of the findings from this study to current design approaches are discussed in detail.

• Korean Journal of Social Welfare Studies
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• v.48 no.1
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• pp.173-206
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• 2017

The purpose of this meta-analysis was to address two questions: (1) To what extent are types of child abuse related to psycho-social maladjustment of the abused? (2) Do relations found in this study vary by the gender, sample size, year of publication, types of publication, and respondents' age? The materials of this study were based on 14 variables obtained from 104 published and unpublished (doctoral disserations and master's theses) research papers over a span of 26 years(1990-2016). Child abuse related variables were categorized into physical abuse, emotional abuse, neglect, and abuse while psycho-social maladjustment grouped as internal (anxiety, depression, withdrawal, and anxiety/depression) and external problem behaviors(aggression, problem behavior, and delinquency). Major findings were: Medium effect size of emotional abuse, abuse, physical abuse, neglect on psycho-social maladjustment among the abused were calculated. Emotional abuse was highly related to every internal and external problem behaviors. Neglect was found to have higher effect size in external problem behaviors than internal problem behaviors. Publication types moderated the association between types of child abuse and internalization while year of publication, number of samples and publication types showed moderation effects on the relation between types of child abuse and externalization. Finding suggest that future studies on child sexual abuse and those on intervention outcome are required and use of well validated instruments are essential.

• Korean Journal of Childcare and Education
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• v.10 no.3
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• pp.5-29
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• 2014

The purpose of this study was to find out various problem behaviors of children who were not diagnosed with any disability, but instead, engaged in problem behaviors. This study also intended to review the difficulties of children with problem behaviors, their teachers' difficulties and needs, to suggest support for child care and education teachers. This study conducted semi-structured qualitative interviews with eight child care and education teachers. The interviews were transcribed into text and analyzed by contents. The results of this study are as follows. Problem behaviors of children described by teachers were classified into external and internal types. In addition, children with problem behaviors had experienced difficulties in maintaining relationships with their teachers, peers and parents. Many teachers were not successful to provide appropriate support for preschoolers who demonstrated problem behaviors in classrooms or some teachers provided individualized support. Teachers adapted the behavioral and the psychological approaches to problem behaviors of preschoolers. However, teachers reported difficulties with children with problem behavior and brought up the following issues on teaching children with problem behaviors; managing troubled matters happening in the class, difficulty in controlling teacher's emotions on problem behaviors, the lack of time, the integrated child care time without teacher in charge of child, the interruption in activity progress, the lack of a special way to deal with problem behaviors, and difficulty in cooperation with families through parents-teacher counseling sessions. Teachers counseled with parents who had a child with problem behaviors and revealed that parents reacted to problem behaviors in various ways such as embarrassment, acceptance, ignorance, or avoidance. Most teachers received assistance and support for teaching children with problem behaviors, from families, local communities and in-service training. Lastly, teachers with preschoolers with problem behaviors needed the support of experts on managing behavior problems, assistant teaching personnel, education for parents and teachers, respects for teachers, psychological counseling or play therapy from professional service agencies, diagnosis service at child care and education centers which children attended, and support networking with agencies. Teachers also required the family support of medical diagnosis and psychological counseling and financial support from the government.

• Child Health Nursing Research
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• v.17 no.1
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• pp.39-47
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• 2011

Purpose: This study was done to determine whether a parenting education program using responsive teaching strategies is effective for parenting stress, maternal interactional behavior and behavioral problems in children at risk for Attention Deficit Hyperactivity Disorder (ADHD). Methods: Participants in this study were 17 elementary school children and their parents. The ADHD risk group was determined by scores on the Korean-ADHD Rating Scale. The parenting education program was developed based on Dr. Mahoney's responsive teaching curriculum. Mothers participated in the program once a week for 8 sessions. Treatment outcome was evaluated using the Korean version of the Child Behavior CheckList (K-CBCL), parenting stress, maternal interactional behavior, and child pivotal developmental behavior. Data were analyzed using Wilcoxon signed rank test, Mann-Whitney test, and regression analysis. Results: After the parenting education program, no significant difference in parenting stress (Z=-1.00, p=.320) was found, but there was a significant decrease in the child's internal behavior problems (Z=-2.05, p=.040), and also a significant improvement in maternal interactional behavior and a significant difference in child pivotal developmental behavior (Z=-2.67, p=.008). Conclusion: The results indicate that parenting education programs based on responsive teaching strategies are effective and that application of a program is recommended to prevent behavioral problems and improve maternal child interaction for children at risk for ADHD.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.25 no.3
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• pp.142-155
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• 2014

Objectives : The aim of this study was to develop an assessment tool for measurement of children's functioning in the mental health service. We conducted a preliminary study to develop a sensitive and inclusive scale focused on the functional changes of children rather than just focusing on their symptoms or screening. Methods : The Child and Adolescent Functional Assessment Scale and the Korean-Child Behavior Checklist (K-CBCL) were both administered to 134 parents of children with emotional or behavioral problems who participated in the Aizone program and also to 186 parents of elementary school children in the Seoul metropolitan area as a control group. SPSS version 12.0 was used for statistical analysis. Results : Most of the reliability coefficients were over 0.70 except those of the conduct behavior items, which showed relatively high internal consistency. The corrected item-total correlations ranged from .411 to 758, except those of conduct behavior items and special measure items. In a concurrent validity test with K-CBCL, the total behavior problem score of K-CBCL was highly correlated with the total score of the Child and Adolescent Functional Assesment Scale (r=.610). For the construct validity, confirmatory factor analysis was performed for each of four areas, including behavior (at home/school), achievement, peer relationship, and emotion. Conclusion : The results showed that the scale was statistically reliable and valid, except for conduct behavior items. This study was conducted only for parents with elementary children. An adolescents group should be included in future studies.

• The Korean Journal of Elementary Counseling
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• v.9 no.2
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• pp.163-173
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• 2010

This study was designed to develop a teacher's rating scale of elementary school student's school maladjustment. 50 behavior were drawn as elementary school student's school maladjustment behavior from the responses of elementary school teachers. To identify sub-factors of the scale, 60 teachers rated their 240 student's behavior and the collected data were analyzed by using factor analysis. 4 sub-factors were identified as the result : aggressive selfish behavior, misconduct of lesson and classroom rules, passive unsociable behavior and positive evasion of school activities. To identify the validity of the scale, the data from 120 students were analyzed through the concurrent validity between the scale and the teacher rating scale of school maladjustment for Student Problem Behavior Checklist for Elementary School students(Kim & Hwang, 2009). To examine the reliability of the scale, test-retest correlations were calculated by using the data from 120 students and internal consistency coefficients were calculated by using the data from 120 students. The results showed that Teacher's rating Scale of Elementary School Student's School Maladjustment was valid and reliable.

• Education of Primary School Mathematics
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• v.22 no.4
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• pp.223-237
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• 2019

There is a close interaction between the linguistic-syntactic representation system and the affective representation system that appear in the mathematical process. On the other hand, since the mathematical conceptual system is fundamentally metaphoric, the analysis of the mathematical concept structure through linguistic representation can help to identify the source of cognitive and affective obstacles that interfere with mathematics learning. In this study, we analyzed the problem-solving protocols of mathematical gifted children from the perspective of cognitive language and meta-affect to identify the relationship between the functional characteristics of the text and metaphor they use and the functional characteristics of meta-affect. As a result, the behavior of the cognitive and affective characteristics of mathematically gifted children differed according to the success of problem solving. In the case of unsuccessful problem-solving, the use of metaphor as an internal representation system was relatively more frequent than in the successful case. In addition, while the cognitive linguistic aspects of metaphors play an important role in problem-solving, meta-affective attributes are closely related to the external representation of metaphors.