• Journal of The Korean Association For Science Education
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• v.9 no.1
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• pp.69-74
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• 1989

For the advancement of research in biological education in Korea, research trends shown in Journal of Biological Education(JBE)of England were analyzed by using a PC program(REFMENU). Papers Published in JBE between 1977 and 1987 were registered on the program with classifying keys of biological education and biology including names of authors, year, title, volume pages, and key words. Those input-date were analyzed by sorting depend-ing on either the classifying keys or the key words. Among the 361 papers 28.8% was dealing with the theory of science education. The rest dealt with biology and biological education, together. Of the six categories of biological education, the research on biological curriculum was 41 % of total and was the most. The major trends in this category was in developing the content of the curriculum. In the research of biological instruction, 37 papers dealt with the instruction theory and the rest 60 papers dealt with the tactics of Instruction. Of the 60 papers on materials in biological education, the research in developing the biological material was the most. Thus, the general research trend was far more practical aspect than the theoretical aspect of biological education. In the analysis of the papers depending on the biological categories, the one dealt with ecology was the most(26.8%). The rest papers showed almost even distribution in the 13 categories of biology. The results of this analysis was discussed by comparing with the research trends in Korea to suggest the possible future studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.26-33
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• 2016

Recently, the use of transformer-less UPS has increased to improve the efficiency of UPS. However, transformer-less UPS is required in three-phase four-wire input IGBT PWM rectifier and the existing three-phase three-wire PFC algorithm cannot be applied in the three-phase four-wire system due to the neutral current problem of UPS input. To control the three-phase four-wire input IGBT PWM rectifier, there are two existing algorithms: 3D SVM and single phase control method. These two algorithms have advantages/disadvantages in controlling the rectifier. The single phase control method is unstable for controlling the rectifier and the 3D SVM method has a problem that must increase the L value of the input-side inductor considerably. Therefore, this paper proposes digital single phase control technology and another new algorithm considering the d-q control, to improve the characteristics of the existing control algorithm. In addition, this paper performed a simulation and experiment based on the proposed control algorithm. The simulation results showed that the proposed technology can control three-phase four-wire IGBT PWM rectifier in a stable manner and can also reduce the neutral current. The proposed algorithm is a useful tool for controlling the three-phase four-wire IGBT PWM rectifier.

• Korean Journal of Human Ecology
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• v.21 no.3
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• pp.439-451
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• 2012

Maternal interaction behavior, language input and children's language of 34 multicultural families were compared with those of ordinary families. MLU's of multicultural mothers and their children were shorter than those of ordinary Korean mothers and children. Positive maternal interaction behaviors of multicultural mothers were significantly lower than those of ordinary mothers. Correlational analyses revealed that there were positive correlations among maternal interaction behaviors, mother's MLU and children' MLU in multicultural families. However, there were no such correlations in ordinary families. Findings suggest language education and support for multicultural mothers be an effective policy for their children's language development.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.1
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• pp.71-81
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• 2020

This paper proposes a possibility of using active front-end rectifier with the SVPWM method for induction motor speed control, which is applicable to small electric propulsion boats. The proposed method can produce a more precise sinusoidal input current waveform and a higher power factor than conventional methods. Its speed, torque, input current, DC voltage, and load current control performance are similar to or better than those of conventional methods. Through computer simulations using the PSIM program, the validity of the proposed method was verified by comparing and analyzing the characteristics of the conventional methods and the proposed method.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.527-533
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• 2020

The purpose of this study is to explore the experience of graduates' career success who actively participated during their school days. The experience of participation in education has been explored from three perspectives: input, environment, and output. The first factor which is the input includes the admission process, motivation for application, and methods of appropriating tuition fees. The second factor which is the environment includes the interrelationships with both in and out of school activities, in-class activities, and in-college members. Lastly, the output factor of university education includes the results of university education and the perception of social advancement. The subjects of the study were 21 students who succeeded in entering society based on their goals. The interviews and surveys were conducted, and the factors affecting their career success were analyzed by dividing them into three upper categories and each category is to create implications for the future direction of university education.

• Smart Structures and Systems
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• v.26 no.6
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• pp.693-701
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• 2020

The conventional Kalman Filter (KF) provides a promising way for structural state estimation. However, the physical parameters of structural systems or models should be available for the estimation. Moreover, it is not applicable when the loadings applied to the structures are unknown. To circumvent the aforementioned limitations, a two-stage KF with unknown input approach is proposed for the simultaneous identification of structural parameters and unknown loadings. In stage 1, a modified observation equation is employed. The structural state vector is estimated by KF on the basis of structural parameters identified at the previous time-step. Then, the unknown input is identified by Least Squares Estimation (LSE). In stage 2, based on the concept of sensitivity matrix, the structural parameters are updated at the current time-step by using the estimated structural states obtained from stage 1. The effectiveness of the proposed approach is numerically validated via a five-story shearing model under random and earthquake excitations. Shaking table tests on a five-story structure are also employed to demonstrate the performance of the proposed approach. It is demonstrated from numerical and experimental results that the proposed approach can be used for the identification of parameters of structure and the external force applied to it with acceptable accuracy.

• Journal of Practical Engineering Education
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• v.9 no.2
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• pp.139-148
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• 2017

As the connection between objects and computers becomes easier, learning using physical computing is presented as a good alternative to solve the problems raised in programming education for beginners. In this paper, we propose a training method that can be applied to basic programming courses for beginners. To do this, we will proceed with a basic programming lecture based on the physical computing method. Currently, physical computing courses focus on various input sensor connection methods and output device control. However, the content of programming education using physical computing materials is lacking. In this paper, we proposed and tested a teaching method that is used in programming education by using low cost materials used in physical computing.

• Journal of the Korean association of regional geographers
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• v.8 no.4
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• pp.480-491
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• 2002

The purpose of this study is to construct interregional input-output table for multi-regions using non-survey methods. Despite of wide use of interregional input-output table, there have been continuing debates with respect to it's accuracy mostly when it is constructed by non-survey method. The best ideal one is to construct through real survey, while we must pay much time and cost. With regard to this concern, Hulu and Hewings developed a step by step method for the estimation of interregional input coefficients for the Indonesian economy which might be a challenge for the limitation of location quotient method, for which Round pointed out earlier. A five regions interregional input-output table for Korea is developed in this study by expanding Location Quotient method. Some development was made, however, according to the degree of collection of data and the assumption in treating the interregional flows. Finally, a comparison was made for the accuracy of input coefficients between the real surveyed and derived ones.

• Journal of Korean Biological Nursing Science
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• v.5 no.2
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• pp.13-19
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• 2003

Purpose : The purpose of this study was to investigate the effects of the education using short messaging service(SMS) on fasting blood sugar(FBS) and diabetes adherence. Method : Forty-five diabetic patients being assessed pre and post intervention was used to assess the effectiveness of the education. Participants were requested to input the FBS and 2 hours post-prandial blood sugar everyday in http://www.biodang.com by cellular phone or wire Internet. The goal of the education was to lower FBS and keep diabetes adherence. The education was applied to the for 12 weeks. The education consisted of continuous education and reinforcement of diet, exercise, medication adjustment, as well as frequent self-monitoring of blood glucose levels. The education performed weekly. All medication adjustments were communicated to the participants' doctor. FBS and diabetes adherence were measured before and after the education. Results : The education using SMS of cellular phone had decrease FBS and increase oral medication taking, exercise, foot care, and hypoglycemia preparation adherence.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.586-592
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• 2012

One approach of the control of a nonlinear system that has gained some success employs a fuzzy structure in cooperation with a neural network(ANFIS). The traditional ANFIS can only model and control the process in single-dimensional output nature in spite of multi-dimensional input. The membership function parameters are tuned using a combination of least squares estimation and back-propagation algorithm. In the case of a mobile robot, we need to drive left and right wheel respectively. In this paper, we proposed the control system architecture for a mobile robotic system that employs the 2-input 2-output ANFIS controller for trajectory tracking. Simulation results and preliminary evaluation show that the proposed architecture is a feasible one for mobile robotic systems.