• International Journal of Automotive Technology
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• v.4 no.4
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• pp.181-191
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• 2003

Since the nonlinearity and uncertainties which inherently exist in vehicle system need to be considered in active suspension control law design, this paper proposes a new control strategy for active vehicle suspension systems by using a combined control scheme, i.e., respectively using a genetic algorithm (GA) based self-tuning PID controller and a fuzzy logic controller in two loops. In the control scheme, the PID controller is used to minimize vehicle body vertical acceleration, the fuzzy logic controller is to minimize pitch acceleration and meanwhile to attenuate vehicle body vertical acceleration further by tuning weighting factors. In order to improve the adaptability to the changes of plant parameters, based on the defined objectives, a genetic algorithm is introduced to tune the parameters of PID controller, the scaling factors, the gain values and the membership functions of fuzzy logic controller on-line. Taking a four degree-of-freedom nonlinear vehicle model as example, the proposed control scheme is applied and the simulations are carried out in different road disturbance input conditions. Simulation results show that the present control scheme is very effective in reducing peak values of vehicle body accelerations, especially within the most sensitive frequency range of human response, and in attenuating the excessive dynamic tire load to enhance road holding performance. The stability and adaptability are also showed even when the system is subject to severe road conditions, such as a pothole, an obstacle or a step input. Compared with conventional passive suspensions and the active vehicle suspension systems by using, e.g., linear fuzzy logic control, the combined PID and fuzzy control without parameters self-tuning, the new proposed control system with GA-based self-learning ability can improve vehicle ride comfort performance significantly and offer better system robustness.

• Journal of the Korean Institute of Educational Facilities
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• v.9 no.5
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• pp.5-12
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• 2002

High-speed telecommunication has brought variety of changes in every field of the world at large. In the field of education, use of multimedia has been positively introduced as teaching and learning tools. In addition, introduction of remote education as well as information and communication technology (ICT) has led an educational system gone into melting pot. These changes have known to be impossible without the provision of the infrastructure of telecommunications such as cabling, cable pathway, telecommunication equipments, and space for the equipments. Although the infrastructure of telecommunications should be fully considered from the early stage of the building design, most of the existing buildings have only cabling for voice communication such as telephone. As a result, heavy expenses are required for the installation of new telecommunication equipments. Such problems as defilement of the appearance of the building and a falling-off in reliability of telecommunication line are caused by the exposed cabling, when the cabling pathway and/or the space for the equipments are not reserved. Considering over 70% of error in telecommunication is coming from the cabling in building, it is necessary to reserve the space for efficient maintenance of the cabling and the equipments. In recent years, the national standard(TTAS.KO-04.0005) on the reservation of space for telecommunication cabling and equipments in residential and commercial building is established and applied for the building design. As well, the standard is in force for the educational buildings. In this study, we try to provide the guidelines for the design of telecommunications infrastructure in educational buildings for the purpose of efficient operation of education information and ICT.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.10
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• pp.516-523
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• 2000

In this paper, intelligent methods using digital protective relay in power supervisory control system is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which has various load environments and capacities in power systems. The spectrum pattern of input currents was used to monitor to state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrums pattern caused by faults were detected. For diagnosis of the fault detected, the fuzzy fault tree was derived, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, was solved. The solution of the fuzzy relation equation shows the possibility of each fault's occurring. The results obtained are summarized as follows: 1) The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protective relay is improved within ${\pm}5%$. 2) Using clustering algorithm by unsupervisory learning, an on-line fault detection method, not affected by the characteristics of loads and rates, was implemented, and the degree of dependency by experts during fault detection was reduced. 3) With the fuzzy fault tree, fault diagnosis process became systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.

• The Journal of Korean Association of Computer Education
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• v.21 no.4
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• pp.1-10
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• 2018

Block programming environment, which is represented by Scratch in elementary and middle school programming education, is suitable for learner's characteristics and cognitive level, and is recommended not only for beginners. Transference to the text programming environment after the block programming is essential for understanding the data processing process, understanding the accuracy and efficiency aspects of algorithms, and creating SW activity. In addition, it is presented step by step in the programming curriculum. In this study, developed WithBlock the online evaluation system for the purpose of transference from a block programming to a text programming environment. The developed system can solve the same algorithm problem in both block and text programming environment, and it can be used for elementary and secondary programming education by automatically scoring the written code and providing immediate feedback. In order to applicable to programming education in elementary and secondary surveyed the usability, learning possibility, interest and satisfaction of WithBlock. The results of the survey showed that it can be used for programming education.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.4
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• pp.539-554
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• 2019

This study suggests a conceptualization model of 'cultural inclusiveness' organically connected to social inclusiveness, by expanding the implications of urban inclusiveness to the domain and relationship. Based on the process of necessity of relation, connection of space, and execution of act, the cultural inclusiveness could be connected to the formation of organic/learning relation, the creation of openness focusing on public space, and the practice of diverse subjects. Concretely, the concept of cultural inclusiveness is applied to the case of 'Hongdae-ap'. The recent Hongdae-ap is showing the value of coexistence such as the establishment of environment that could protect the diversity of individual subjects and groups(artists, residents, government officials, students, cultural activists, citizens, tourists, and etc.), the formation of public space such as 'Hongdae-up playground', 'pedestrian-friendly street', and 'Gyeongui-Line book street', social network service & horizontal network, and access.

• Journal of the Korean School Mathematics Society
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• v.14 no.1
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• pp.1-29
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• 2011

In this study, we designed and constructed a very low-cost electronic board in order to test its efficiency in the classroom as well as provide an easy-to-follow model for front-line teachers to re-create and utilize for their own academic use. For our sample size, we tested 143 high school first grade students. In mathematical achievement, we found meaningful improvement in both genders but we did not find any meaningful gender differences. In the mathematical disposition test, we also found some meaningful changes in curiosity and flexibility in both genders but did not find any meaningful gender differences either. Based on this study, we propose using our low-cost electronic board system, which is easy to make and effective in mathematical achievement, instead of recently promoted high-cost electronic board systems.

• Journal of Korean Library and Information Science Society
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• v.43 no.3
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• pp.333-352
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• 2012

Building a new library and remodeling an existing library for the multi-cultural space is a recent trend of the university libraries. That is, the spaces for using the digital and multimedia equipments, the rooms for reading and studying, the spaces for the cultural activities such as watching movies and holding an exhibition, and the spaces for the communication and refreshment are increasing in the libraries. However, this movement of securing and providing the new spaces is not closely connected with the off-line services and happens without the consideration of how to change the librarian's role and position. Therefore, the university libraries need to plan and provide the multi-learning space rather than the multi-cultural space considering the university library is an academic organization. Additionally, understanding the purpose of the university libraries, user's need, utilization method of books and considering the librarian's roles and placement are necessary in planning and providing the space of the libraries.

• School Mathematics
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• v.18 no.4
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• pp.881-901
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• 2016

This study is about investigating students' recognition and expression on relationship of 'time, distance, speed' via teaching experiment. In this process, students showed not only a change in perception of the relationship of 'time, distance, speed' but also recognizing the average speed as a viewpoint of the slope of the line connecting the end points of the interval in the distance function as well as another way of perceiving average speed of a height of a rectangle. In this process, the study shows the scene of expanding the relation of 'distance = time ${\times}$ speed' to 'distance = time ${\times}$ average speed', and also the student who makes the continuous reasoning shows the possibility of constructing a new function that can explain the change of the primitive function by allocating the average rate of change to the interval. Although this study was conducted with a limited number of students, this study suggests some implications through the observation of relationship of 'time, distance, speed' the students'. We hope that these results will be the starting point for various studies for constructing the integral learning model in the future.

• The Korean Journal of Food And Nutrition
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• v.33 no.3
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• pp.347-355
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• 2020

Cognitive impairment is considered to be key research topics in the field of neurodegenerative diseases and in understanding of learning and memory. In the present study, we investigated neuroprotective effects of Schisandra chinensis (SC) and Ribes fasciculatum (RF) extracts in hydrogen peroxide-induced neuronal cell death in vitro and scopolamine-induced cognitive impairment in Sprague Dawley^® (SD) rat in vivo. Apoptotic cell death in neuroblastic PC12 cell line was induced by hydrogen peroxide for 1 hour at 100 μM. However, mixture of SC and RF treatment prevented peroxide induced PC12 cell death with no neurotoxic effects. For in vivo experiment, the effect of SC and RF extracts on scopolamine-induced cognitive impairment in SD rat was evaluated by spontaneous alternation behavior in Y-Maze test. After 30 min scopolamine injection, the scopolamine-induced rats presented significantly decreased % spontaneous alteration and acetylcholine level, compared to non-induced group. However, treatment of SC+RF extracts rescued the reduced % spontaneous alteration with acetylcholine concentration from hippocampus in scopolamine-induced rats. These results suggested that mixture of SC and RF extract may be a potential natural therapeutic agent for the prevention of cognitive impairment.

• Journal of Korean society of Dental Hygiene
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• v.15 no.1
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• pp.137-146
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• 2015

Objectives: This study was obtained to identify current education status of the community dental hygiene practice. Methods: It was designed cross section and self-reported on-line questionnaire(Survey monkey). It was performed probability sampling by targeting 82 dental hygiene schools(each one faculty member) in charge of community dental hygiene curriculum and 254 community health centers's community dental hygienists whom was working at oral health section. The response rate was 60% and 53%, respectively. The questionnaire consisted of time, duration, practice group, evaluation method, and practice contents including 63 learning objectives of dental hygiene. Results: Nearly half of these schools conduct such community field work practice in the spring semester of the junior year. This practice was mainly progressed based on average 4 students as one team per each one school for 7-8 hours a day during the period of more than 5 weeks(p<0.05). However, in case of both school and community health center, almost half of feedback after practice was not achieved and there was a difference in needs for practice education between schools and community health center. Conclusions: We should be considered that a sufficient consultation for the practice environment and its contents between schools and community health centers. It was considered that development of a standardized practice manual reflecting such requirement.