• Korean Journal of Childcare and Education
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• v.16 no.1
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• pp.75-98
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• 2020

Objective: This study aimed to examine the influences of household chaos on self-control of young children and to investigate whether teachers' limit-setting styles had moderating effects. Methods: The participants were 184 children (83 boys and 101 girls), at age 3 -5, their mothers and teachers working at daycare centers located in Seoul and Gyeonggi-do. The data were analyzed by descriptive statistics, Pearson's correlation, and hierarchical regression. Moderating effects were examined using the Mplus8.0 program. Results: The results indicated that household chaos as well as teacher's permissive and logical limit-setting styles had significant effects on self-control of preschoolers. The lower the level of household chaos was, the higher the level of self-control of preschoolers was. The level of self-control was more likely to be high when teachers used logical limit-setting with detailed explanation to children whereas it was lower when they used more permissive limit-setting. In addition, teachers' logical limit-setting moderated the relation between household chaos and self-control of preschoolers. That is, the effects of household chaos on preschoolers' self-control were mitigated when the level of logical limit-setting was high compared to when it was low. Conclusion/Implications: The results suggested that both household chaos and teachers' limit-setting styles play important roles in increasing self-control of preschoolers.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.299-308
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• 2007

This study proposes a two-layer hierarchical control system that integrates active front wheel steering and four wheel braking torque control to improve vehicle handling performance and stability. The first layer is a robust model matching controller (R-MMC) based on linear matrix inequalities (LMIs), which optimizes an active front steering angle compensation and a desired yaw moment control, and calculates reference wheel slip for the target wheel according to the desired yaw moment. The second layer is a moving sliding mode controller (MSMC) that can track the reference wheel slip in a predetermined time by commanding proper braking torque on the target wheel to achieve the desired yaw moment. Since vehicle sideslip angle measurement is difficult to achieve in practice, a sliding mode observer (SMO) that requires only vehicle yaw rate as the measured input is also developed in this study. The performance and robustness of the SMO and the integrated control system are demonstrated through comprehensive computer simulations. Simulation results reveal the satisfactory tracking ability of the SMO, and the superior improved vehicle handling performance, stability and robustness of the integrated control vehicle.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.49-51
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• 2005

Robot control involves advance programming, scientific and high technology. The systematic and methodological aspects of robot controls often results in having superficial control design problems that can negatively affect the robot application, usability and appeal. User friendly interface of robot control is extremely advantageous and more attractive. To illustrate, the application of medical robot is usually handled by clients who have little background in advance programming language. Thus, it would be difficult if the client needs to use programming language to control the robot. It would justify better if the robot control is presented in a meaningful interface to the client. This way the robot application would be more natural and user friendly. This paper describes the method of developing the user interface for web based communication to control an internet robot named Tarou. The web based communication tasks involves three levels. The first one accommodates on the client sending commands to robot through the internet. The next communication level relates to the robot receiving the commands sent by the client. The final communication level generates on sending feedback on status of commands by the robot to the client. The methodology used here can be elaborated in four hierarchical steps; identify user needs and robot tasks, identify the enhancing tag reference used by the server, induce the tag into HTML, present the HTML in attractive user interface as the client control panel.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.362-364
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• 1992

In this paper, the development of a fiber optic network for an integrated digital protection relay system is described. The structure of the developed network is determined to loosen the optic requirements and to have good extensibility while providing sufficient functions for protection and control for substations. The network has a hierarchical structure with two levels. The upper level handles data for monitoring and control of the system with star topology. The lower level manages the real time data for bus protection with one-to-one connections. Communication flows of each level are described. The HDLC is employed as the network protocol.

• Korean Journal of Child Studies
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• v.37 no.3
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• pp.39-51
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• 2016

Objective: The present study examined the effects of school violence victimization and self-control on cyberbullying perpetration in middle school students and investigated whether self-control moderated the relationship between school violence victimization and cyberbullying perpetration. Methods: The participants of this study were 315 middle school students (172 boys; 143 girls) from three middle schools in Seoul and Incheon. To measure the level of cyberbullying perpetration, the Bullying/Victimization Questionnaire was used. School violence victimization and self-control were measured via the School Violence Victimization Scale and the Self-Control Scale, respectively. The data were analyzed by means of descriptive statistics and hierarchical regressions. Results and Conclusion: The results indicated that school bullying victimization level increased cyberbullying perpetration level whereas self-control level decreased cyberbullying perpetration. In addition, self-control moderated the effect of school violence victimization on cyberbullying perpetration. That is, the influence of school bullying victimization on cyberbullying perpetration was greater when self-control was low, compared to when it was high.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.459-468
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• 2017

This study investigated the factors influencing how obesity stress and health belief impact weight control behavior among nursing students. Data were collected from nursing students in U city between September 1 and October 10, 2016 and analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and hierarchical multiple regression. Among the general characteristics of the subjects, gender (t=2.30, p=0.044) and health status (F=8.03, p<0.001) significantly influenced weight control behavior. There were negative correlations between diet therapy of weight control behavior (r=-0.26, p<0.001), exercise therapy (r=-0.25, p<0.001), behavior modification therapy (r=-0.29, p<0.001), and perceived barriers in health belief. In addition, acquiring special knowledge for weight control behavior showed positive correlations in obesity stress (r=0.42, p<0.001), perceived susceptibility (r=0.25, p<0.001) and perceived benefits (r=0.19, p<0.001). Furthermore, the significant factors influencing weight control behavior were perceived barriers (${\beta}=-0.30$, p<0.001) and obesity stress (${\beta}=0.20$, p<0.05) in health belief, and these factors explained 17.2% of the variance. Based on the study results, it is necessary to develop and apply effective educational programs that can influence weight control behavior through gender, health status, obesity stress and health beliefs, which determine weight control behavior of nursing students.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.3
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• pp.238-248
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• 2016

In this study, an automatic command mode transition strategy of direct power control (DPC) is proposed for permanent magnet synchronous generators (PMSGs) medium-voltage (MV) offshore wind turbines (WTs). Benchmarking against the control methods are performed based on a three-level neutral-point-clamped (NPC) back-to-back type voltage source converter (VSC). The ramping rate criterion of complex power is utilized to select the switching vector in DPC for a three-level NPC converter. With a grid command and an MPPT mode transition strategy, the proposed control method automatically controls the generated output power to satisfy a grid requirement from the hierarchical wind farm controller. The automatic command mode transition strategy of DPC is confirmed through PLECS simulations based on Matlab. The simulation result of the automatic mode transition strategy shows that the proposed control method of VOC and DPC achieves a much shorter transient time of generated output power than the conventional control methods of MPPT and VOC under a step response. The proposed control method helps provide a good dynamic performance for PMSGs MV offshore WTs, thereby generating high quality output power.

• Korean Journal of Human Ecology
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• v.20 no.3
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• pp.595-609
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• 2011

This study examine the mediating role of teacher-child relationships on children's effortful control and problem behaviors. Boys and girls were analyzed separately. Participants were 221 children(l21 boys, 100 girls; aged 4-5), their mothers and 19 child care teachers. The teachers completed rating scales to measure the perception of teacher-child relationships and the children's problem behaviors. Children's effortful control was rated by the mother's questionnaire. The collected data was analyzed using descriptive statistics, t-tests, Pearson's correlations, and hierarchical multiple regressions. Results indicated that children's effortful control was negatively related to their problem behaviors. In addition, the associations between children's effortful control and their aggressive behaviors were mediated by conflictual teacher-child relationship. Also, the relation of girl's effortful control and her withdrawal behavior was partially mediated by conflictual teacher-child relationship. Finally, the association between boy's effortful control and his withdrawal behavior was mediated by close teacher-child relationship. Results suggest the importance of teacher-child relationships in the context of intervention planning for preschooler's problem behaviors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1582-1587
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• 2005

In coagulant control of water treatment plants, rule extraction, one of datamining categories, was performed for coagulant control of a water treatment plant. Clustering methods were applied to extract control rules from data. These control rules can be used for fully automation of water treatment plants instead of operator's knowledge for plant control. To perform fuzzy clustering, there are some coefficients to be determined and these kinds of studies have been performed over decades such as clustering indices. In this study, statistical indices were taken to calculate the number of clusters. Simultaneously, seed points were found out based on hierarchical clustering. These statistical approaches give information about features of clusters, so it can reduce computing cost and increase accuracy of clustering. The proposed algorithm can play an important role in datamining and knowledge discovery.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.187-192
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• 2004

In this paper, it is presented a new technique to the design and real-time implementation of fuzzy control system based-on digital signal processors in order to improve the precision and robustness for system of industrial robot. Fuzzy control has emerged as one of the most active and fruitful areas for research in the applications of fuzzy set theory, especially in the real of industrial processes. In this thesis, a self-organizing fuzzy controller for the industrial robot manipulator with a actuator located at the base is studied. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variable of the controller, In the synthesis of a FLC, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult, SOFC is proposed for a hierarchical control structure consisting of basic level and high level that modify control rules. The proposed SOFC scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Performance of the SOFC is illustrated by simulation and experimental results for robot with eight joints.