• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.3-6
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• 2008

Electrolytic in-process dressing (ELID) grinding is a new technique for achieving a nanoscale surface finish on hard and brittle materials such as optical glass and ceramics. This process applies an electrochemical dressing on the metal-bonded diamond wheels to ensure constant protrusion of sharp cutting grits throughout the grinding cycle. In conventional ELID grinding, a constant source of pulsed DC power is supplied to the ELID cell, but a feedback mechanism is necessary to control the dressing power and obtain better performance. In this study, we propose a new closed-loop wheel dressing technique for grinding wheel truing that addresses the efficient correction of eccentric wheel rotation and the nonuniformity in the grinding wheel profile. The technique relies on an iterative control algorithm for the ELID power supply. An inductive sensor is used to measure the wheel profile based on the gap between the sensor head and wheel edge, and this is used as the feedback signal to control the pulse width of the power supply. We discuss the detailed mathematical design of the control algorithm and provide simulation results that were confirmed experimentally.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1186-1193
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• 1991

This paper proposed a trajectory controlmethod for a robot manipulator by using neural networks. The total torque for a manipulator is a sum of the linear feedback controller torque and the neural network feedfoward controller torque. The proposed neural network is a multilayer neural network with time delay elements, and learns the inverse dynamics of manipulator by means of PD(propotional denvative)controller error torque. The error backpropagation (BP) learning neural network controller does not directly require manipulator dynamics information. Instead, it learns the information by training and stores the information and connection weights. The control effects of the proposed system are verified by computer simulation.

• Korean System Dynamics Review
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• v.2 no.1
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• pp.69-92
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• 2001

The Managing and measuring performance have long been a popular topic in business. Traditions of financially-oriented managing and measuring performance have provided managers with relatively objective and scientific results of measuring performance until now. But today the value of organization is influenced more by intangible assets than tangible assets. Nobody thus believes that the performance and the value of organization can be measured by financial indicators only. In this background, numerous researches have been conducted to find alternatives to measuring the value of organization's intangible assets. One of the remarkable achievements would be "Balanced Score Card (BSC), "which covers three sectors of indicators, each from customer relations, internal process innovations, and learning and human resource development, in addition to traditional financial indicators. Unfortunately, even BSC, let alone others, fails to accomodate all performance indicators as a holistic system. Namely, performance measuring techniques including BCS, at present, fail to reflect the dynamic features in their model - i.e., the casual relations and the interactions between the indicators, and there is no way of taking into account the impact of delayed feedback which flows from introduction of new policy and legislative changes, etc. Therefore, this paper attempts to devise a means for adding dynamic features to BSC, by introducing the system dynamics concept, with a focus on the effect of casual relations and feedback structure.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.705-709
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• 1995

The objective of this study is to design a multi-layer neural network which controls the position of excavator's attachment. In this paper, a dynamic controller has been developed based on an error back-propagation(BP) neural network. Since the neural network can model an arbitrary nonlinear mapping, it was used as a commanded feedforward input generator. A PD feedback controller is used in parallel with the feedforward neural network to train the system. The neural network was trained by the current state of the excavator as well as the PD feedback error. By using the BP network as a feedforward controller, no a priori knowledge on system dynamics is need. Computer simulation results demonstrate such powerful characteristics of the proposed controller as adaptation to changing environment, robustness to disturbancen and performance improvement with the on-line learning in the position control of excavator attachment.

• The KIPS Transactions:PartB
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• v.10B no.3
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• pp.237-242
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• 2003

Ant Colony System (ACS) Algorithm is new meta heuristic for hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem (TSP). In this paper, we introduce ACS of new method that adds reinforcement value for each edge that visit to Local/Global updating rule. and the performance results under various conditions are conducted, and the comparision between the original ACS and the proposed method is shown. It turns out that our proposed method can compete with tile original ACS in terms of solution quality and computation speed to these problem.

• Korean Medical Education Review
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• v.23 no.2
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• pp.90-103
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• 2021

This study examined the current status of the medical professionalism curriculum in Korea to suggest a plan to move towards the formation of a professional identity. Professionalism education data from 28 Korean medical schools were analyzed, including the number of courses, required or elective status, corresponding credits, major course contents, and teaching and evaluation methods. Considerable variation was found in the number of courses and credits in the professionalism curriculum between medical schools. The course contents were structured to expand learners' experiences, including the essence and knowledge of professionalism, understanding of oneself, social interaction with others, and the role of doctors in society and the healthcare system. The most common teaching methods were lectures and discussions, while reflective writing, coaching, feedback, and role models were used by fewer than 50% of medical schools. Written tests, assignments and reports, discussions, and presentations were frequently used as evaluation methods, but portfolio and self-evaluation rates were relatively low. White coat ceremonies were conducted in 96.2% of medical schools, and 22.2% had no code of conduct. Based on the above results, the author suggests that professional identity formation should be explicitly included in learning outcomes and educational contents, and that professional identity formation courses need to be added to each year of the program. The author also proposes the need to expand teaching methods such as reflective writing, feedback, dilemma discussion, and positive role models, to incorporate various evaluation methods such as portfolios, self-assessment, and moral reasoning, and to strengthen faculty development.

• Journal of the Korean Society of Earth Science Education
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• v.10 no.3
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• pp.262-277
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• 2017

Digital textbooks enable learning that is appropriate to the characteristics and level of learners through various interactions. The purpose of this study was to develop an instruction model that can more effectively use digital textbooks in elementary science classes and to verify its effectiveness. The results were as follows. The instruction model for helping learners complete their learning by using digital textbooks needs to receive diagnostic assessment and feedback on entry behavior, to build a self-directed learning environment, and to interact with teachers, students, and digital textbooks as scaffolding. In this study, we developed an instruction model using digital textbooks reflecting these characteristic. The instructional model consists of preparation, practice and solidity step. In the preparation step, the learner performs a diagnostic evaluation using digital textbooks. Based on the results, feedback provided at each level can complement the entry behavior and maintain interest in learning activities. In the practice step, self-directed learning is implemented using diverse functions of digital textbooks and various types of data. In the solidity step, learners can internalize the learning contents by reviewing video clips which are provided by teachers, performing problem-solving activities, and accessing outcomes accumulated by learners in the community online. In order to verify the effectiveness of this model, we selected the "Weather and our Life" unit. This experiment was conducted using 101 students in the 5th grade in B Elementary School in Gwangju Metropolitan City. In the experimental group, 50 students learned using a smart device that embodies digital textbooks applied with the instruction model. In the comparative group, 51 students were taught using the paper textbooks. The results were as follows. First, there was a significant effect on the improvement of the learning achievement in the experimental group with low academic ability compared with the comparative group with low academic ability. Second, there was a significant effect on self-directed learning attitude in the experimental group. Third, in the experimental group, the number of interactions with the learner, teacher, and digital textbook was higher than the comparative group. In conclusion, the digital textbooks based on the instruction model in elementary science classes developed in this study helped to improve learners' learning achievement and self-directed learning attitudes.

• Journal of Korean Home Economics Education Association
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• v.30 no.4
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• pp.127-139
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• 2018

The purpose of this study was to develop and examine the effect of flipped learning in hand sewing practice. The flipped learning class was designed to three steps(pre-class, in-class, after-class). Pre-class: Students learned kinds of hand sewing by watching video and ppt. In-class: Students were evaluated for their prior learning through the quiz. After the quiz, instructor had a brief hand sewing demonstration. Then basic hand sewing practice was progressed. After that advanced project(making things using more than 3 kinds of hand sewing methods) was progressed. After-class: Students were evaluated each other through project exhibition. The effectiveness of flipped learning was measured based on the students' self-reflective journals and class awareness surveys. As the results, students were actively participated in flipped learning and satisfied with the overall quality of the flipped learning class. They said that videos, project & feedback were helpful in understanding hand sewing. Flipped learning applied to hand sewing practice showed more positive learning effect than the general practice class.

• Journal of The Korean Association For Science Education
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• v.41 no.2
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• pp.133-144
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• 2021

The purpose of this study is to explore the teaching and learning experiences to improve the positive experiences about science (PES) of scientifically-gifted elementary school students. For this study, 36 students in grades 5~6 at a gifted science education institutes in Seoul were selected and conducted pre-test and post-test for 'Test for Indicators of Positive Experiences about Science (TIPES).' After the weekly science classes of the institutions were over, individual in-depth interviews were also conducted with some students to explore the teaching and learning experiences for improving their PES. The analysis of the results reveals that the science classes for scientifically-gifted students have been shown to improve PES of scientifically-gifted elementary school students. The teaching and learning experiences to improve their PES included eight teaching and learning experiences that appeared in general elementary school students of previous study such as 'practice-centered exploratory activities,' 'student-led class,' 'positive and professional feedback,' 'construction of knowledge through exploration,' 'class considering student's interest and aptitude,' 'use of materials related to real life,' 'smooth communication and collaboration in group activities,' and 'appropriate difficulty in learning content.' There were also six teaching and learning experiences that newly emerged from science-gifted students: 'Learning experience through the strategies for improving scientific creativity,' 'inquiry experience as a little scientist,' 'advanced or accelerated learning experience,' 'learning experience with excellent students,' 'experience helping other students,' and 'experience with high or low achievement'. Based on these results, the practical implications for improving the student's PES are suggested.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.10-18
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• 2014

As the standard of living and leisure time of contemporary people is increasing, people who have interest not only in physical health activities but also in mental health activities are increasing. Also, people who have interest in sports activities, which include entertaining factors are gradually increasing. SporTainment is a compound of the words 'Sports' and 'Entertainment' and it possesses the meaning of doing sports and entertainment simultaneously. In addition, in the immersive media technology field, researches, which increase the feeling of existence and immersion through the stimulation of the consumer's emotional feedback technology, have been actively conducted. Such, emotional feedback technologies are based on fun and excitement and are activities, in which learning effects are included such as games, education, national defense etc. In addition, the emotional feedback technology is expanding in applied services, which maximize the feeling of existence and immersion of the consumers by adding reality effects in the virtual environment. In this research, the presence of the user was increased by developing a realistic bike simulation for the use of SporTainment, which combine emotional effects and reappearance devices in the bike simulation.