• Proceedings of the KIEE Conference
• /
• 2008.10c
• /
• pp.74-76
• /
• 2008

최근 BLDC 모터는 널리 사용되고 있지만, 불필요한 코깅 토크가 발생된다. 본 논문에서는 BLDC 모터의 코깅 토크 감소 방법을 설계하고 실험 하였다. 이론을 바탕으로 한 이 방법은 모터의 Magnet을 움직여 고주파성분을 제거하여 코깅 토크를 감소시키는 방법이다. 4극 24슬롯 BLDC 모터를 이용하여 Flux2D로 시물레이션 하고 계산 결과를 얻었다.

• Annual Conference of KIPS
• /
• 2021.05a
• /
• pp.447-450
• /
• 2021

시뮬레이션을 비롯한 많은 다중 에이전트 환경에서는 중앙 집중 훈련 및 분산 수행(centralized training with decentralized execution; CTDE) 방식이 활용되고 있다. CTDE 방식 하에서 중앙 집중 훈련 및 분산 수행 환경에서의 다중 에이전트 학습을 위한 상태 행동 가치 기반(state-action value; Q-value) 다중 에이전트 알고리즘들에 대한 많은 연구가 이루어졌다. 이러한 알고리즘들은 Independent Q-learning (IQL)이라는 강력한 벤치 마크 알고리즘에서 파생되어 다중 에이전트의 공동의 상태 행동 가치의 분해(Decomposition) 문제에 대해 집중적으로 연구되었다. 본 논문에서는 앞선 연구들에 관한 알고리즘들에 대한 분석과 실용적이고 일반적인 도메인에서의 실험 분석을 통해 검증한다.

• Journal of Energy Engineering
• /
• v.28 no.1
• /
• pp.45-48
• /
• 2019

Currently, the global atmosphere around the world is altering at a very rapid pace. Among those changes, some are beneficial, but most of the changes are lead to destruction to our planet. The area of environmental science is a significant resource for learning more about these changes. Due to the urbanization, the human population is increasing, natural resources becoming very limited. To solve the limited resources issues, recycling is absolutely an alternative source for the new demands and limitations. Recycling education is very important to raise awareness among students and their communities about the need for recycling and what materials are recyclable locally. In this paper, we reported the role of sustainability science and technology and the impact of recycling research education in the middle schools, both in developing countries and Asian countries and also we included the brief data of global recycling of waste.

• Journal of the Semiconductor & Display Technology
• /
• v.14 no.3
• /
• pp.37-43
• /
• 2015

In this paper, a new background subtraction algorithm for video based fence monitoring surveillance systems is proposed. We adopt the sampling based background subtraction technique and focus on the two main issues: handling highly dynamic environment and handling the flickering nature of pulse based IR (infrared) lamp. Natural scenes from fence monitoring system are usually composed of several dynamic entities such as swaying trees, moving water, waves and rain. To deal with such dynamic backgrounds, we utilize the confidence factor for each background value of the input image. For the flickering IR lamp, the original sampling based technique is extended to handle double background models. Experimental results revealed that our method works well in real fence monitoring surveillance systems.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.1
• /
• pp.107-111
• /
• 2011

Polypropylene(PP)/carbon fiber(CF)/multi-walled carbon nanotube(MWCNT) nanocomposites along with various CF and MWCNT contents were prepared in a Twin screw extruder. Electrical, mechanical property and morphology were investigated with a variation of CF and MWCNT contents. From the surface resistance of PP/CF/MWCNT composites, MWCNT can increase the conductivity of composites compared with PP/CF composites without MWCNT. It is suggested that MWCNT and CF can make the conductive network in the polymer matrix. Flexural modulus and Izod impact strength of the PP/CF/MWCNT composites were improved with the increase of CF contents. Morphology showed that length of CF in polymer matrix was shortened by torque during melt mixing with MWCNT. As a result of this phenomenon, the impact strength of composites was somewhat decreased.

• Journal of the Semiconductor & Display Technology
• /
• v.18 no.4
• /
• pp.110-115
• /
• 2019

Blur detection and segmentation play vital role in many computer vision applications. Among various methods, local binary pattern based methods provide reasonable blur detection results. However, in conventional local binary pattern based methods, the blur map is computed by using a fixed threshold irrespective of the type and level of blur. It may not be suitable for images with variations in imaging conditions and blur. In this paper we propose an effective method based on local binary pattern with adaptive threshold for blur detection. The adaptive threshold is computed based on the model learned through the multinomial logistic regression. The performance of the proposed method is evaluated using different datasets. The comparative analysis not only demonstrates the effectiveness of the proposed method but also exhibits it superiority over the existing methods.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.4
• /
• pp.30-35
• /
• 2017

Moving object segmentation from a nonstationary camera is a difficult problem due to the motion of both camera and the object. In this paper, we propose a new confidence-based background subtraction technique from moving camera. The method is based on clustering of motion vectors and generating adaptive multi-homography from a pair of adjacent video frames. The main innovation concerns the use of confidence images for each foreground and background motion groups. Experimental results revealed that our confidence-based approach robustly detect moving targets in sequences taken by a freely moving camera.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1780-1782
• /
• 1999

The ultrasonic motor used here is the windmill type ultrasonic motor operated by single-phase AC source. A metal-ceramic composite component was used as the stator element to generate ultrasonic vibrations. The windmill type ultrasonic motors has only three components; a stator element of two wind-mill shape slotted metal endcaps, a rotor and a bearing. In this paper we proposed a system for torque measurement of piezoelectric ultrasonic motor.

• International Journal of Advanced Culture Technology
• /
• v.11 no.4
• /
• pp.131-140
• /
• 2023

This study aims to investigate the impact of pre-service early childhood teachers' civic awareness and multicultural beliefs on their ability to teach democratic citizenship education and to verify the mediating effect of multicultural beliefs in the relationship between civic awareness and the ability to teach democratic citizenship education. The subjects of the study were 226 pre-service early childhood teachers, and a survey was conducted. As a result of the study, first, the civic awareness of pre-service early childhood teachers influenced the ability to teach democratic citizenship education, and the influence of the sub-variables of civic awareness was in the order of rights awareness, responsibility, community awareness, and rational decision-making awareness. Second, the multicultural beliefs of pre-service early childhood teachers also affected the ability to teach democratic citizenship education, and multicultural understanding had the strongest influence among the sub-variables of multicultural beliefs. Thirdly, we found that multicultural beliefs partially mediated the relationship between civic awareness and the ability to teach democratic citizenship education. Additionally, the results highlight the importance of educational interventions targeting multicultural beliefs, as they partially mediate the relationship between civic awareness and the ability to teach democratic citizenship education.

• Journal of Engineering Education Research
• /
• v.13 no.5
• /
• pp.15-19
• /
• 2010

Upon request from the Tokushima Prefectural Senior High School of Science and Technology, two faculty staff members and eight students of The University of Tokushima visited the high school and set up a chemistry laboratory class for 59 students. Since the participating senior high school students were freshmen, four simple, safe and visual experiments were selected: 1) Water purification, 2) Surface modification, 3) Briggs-Rauscher reaction, and 4) Polymer synthesis and characterization. All experiments received a favorable reception as a follow-up questionnaire verified. Since the high school students enjoyed the experiments it is hoped that the results will strengthen the students' interest in chemistry. It was good opportunity for the observers; they recognized the difficulty of teaching students.