• Advances in nano research
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• 제14권6호
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• pp.521-525
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• 2023

This paper concerned with the vibration of double walled carbon nanotubes (CNTs) as continuum model based on Timoshenko-beam theory. The vibration solution obtained from Timoshenko-beam theory provides a better presentation of vibration structure of carbon nanotubes. The natural frequencies of double-walled CNTs against half axial wave mode are investigated. The frequency decreases on decreasing the half axial wave mode. The shape of frequency arcs is different for various lengths. It is observed that model has produced lowest results for C-F and highest for C-C. A large parametric study is performed to see the effect of half axial wave mode on frequencies of CNTs. This numerically vibration solution delivers a benchmark results for other techniques. The comparison of present model is exhibited with previous studies and good agreement is found.

• 한국생산제조학회지
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• 제19권1호
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• pp.15-25
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• 2010

The objective of this study is to investigate the optimal arrangement of cameras used for the robot's vision control scheme. The used robot's vision control scheme involves two estimation models, which are the parameter estimation and robot's joint angle estimation models. In order to perform this study, robot's working region is divided into three work spaces such as left, central and right spaces. Also, cameras are positioned on circular arcs with radius of 1.5m, 2.0m and 2.5m. Seven cameras are placed on each circular arc. For the experiment, nine cases of camera arrangement are selected in each robot's work space, and each case uses three cameras. Six parameters are estimated for each camera using the developed parameter estimation model in order to show the suitability of the vision system model in nine cases of each robot's work space. Finally, the robot's joint angles are estimated using the joint angle estimation model according to the arrangement of cameras for robot's point-position control. Thus, the effect of camera arrangement used for the robot's vision control scheme is shown for robot's point-position control experimentally.

• Journal of Radiation Protection and Research
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• 제20권4호
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• pp.227-236
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• 1995

선량데이타와 정확한 3차원 선량모델을 이용하여 여러 아크에 대한 선량분포를 조사하였다. 정확한 선량모델에 의해 계산된 선량 값은 판단한 실험식으로 표현이 가능했으며 이는 선량 최적화 과정에서 반복적으로 선량 값을 계산하는데 매우 유용하였다. 360도 아크와 부분 아크에 대한 선량 값을 빠른 속도로 계산하기 위하며 실험적으로 구해진 실린더형 선량모델을 개발하였다. 200개 위치의 정확한 선량 값을 비선형식으로 피팅하여 7개의 변수를 포함하는 실험식을 개발하였다. 결과적으로 이 모델을 이용하는 경우 한 아크에 대한 선량 계산시 400개의 위치를 계산하는데 PC-486으로 1초 이내에서 계산이 가능하였다. 결론적으로 개발된 고속선량모델은 정확한 선량모델에 의한 선량 값과 유사한 값을 제공함으로써 계간속도가 늦은 일반 3차원 선량모델을 대치할 수 있을 것으로 사려된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.786-789
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• 2002

The behaviour of contactors protected by arcs under short-circuit currents is analysed using a simple model to represent the electric circuit and the contactor. In most cases, the protection of contactors against short-circuit currents is entrusted to fuses. Fuses are suitable for preventing excessive damage to the contactor, or parts of the contactor, under short-circuit conditions. In particular, they are capable of limiting the thermal and electrodynamic stresses which can lead to arcing or welding together of the contacts of a contactor. This paper is the Dynamic Motion Analysis of a Moving Contact by Electromagnetic Repulsion Force in Molded Case Circuit Breaker(MCCB)

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1287-1289
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• 1995

For the analysis of hot gas flow due to arc in puffer type $SF_6$ gas circuit breakers(GCBs), a program has been developed by adding function for arcing to the Fluid-in Cells(FLIC) method, which is often used for a two dimensional compressible flow problems, utilizing a simplified enthalpy flow arc model available for arcing. In this paper, the results of arc modelling for 800kV GCB are presented and compared with that of cold gas flow in the interrupters. It is shown that the nozzle clogging is the dominating factor in the pressure rise of the puffer chamber. It permits to estimate the dielectric strength of interrupters.

• 한국정보교육학회:학술대회논문집
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• 한국정보교육학회 2005년도 하계학술대회
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• pp.183-192
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• 2005

이동 통신 가입자 수가 빠르게 늘어가면서 무선 인터넷 기술은 다양한 형태의 데이터 제공이 가능해 지고 이에 대한 교육적 활용에 대한 관심이 증대되고 있다. 이에 따라 무선 인터넷만의 장점인 이동성, 실시간성, 휴대성, 편리성, 개별화, 차별화 등을 이용하여 학습에 적용하는 것은 매우 중요한 의미를 지닌다. 또한 학습에 있어서 학습하고자 하는 욕구인 동기가 중요시되어야 하며 이에 따라 학습 성취도는 큰 영향을 가진다. 따라서, 본 논문에서는 보편적으로 잘 알려진 Keller의 ARCS 모형을 기반으로 하여 무선 인터넷 환경에 적합하도록 수정, 보완하여 동기 모형을 제시하고 적용하고자 한다. 본 모형의 특징은 다음과 같다. 첫째, 개별화 및 차별화에 중점을 두었다. 모바일 환경의 가장 큰 특징인 개별화, 차별성을 부각시켜 동기 전략에 적용하였다. 둘째, 학습자 진단에 비중을 두어 설계하였다. 모바일에서 개별화의 가장 큰 기준이 되므로 정확한 진단을 할 수 있도록 한다. 셋째, 무선 인터넷에 적합한 동기 전략을 제시하여 단계별 적용을 용이하도록 하였다. 넷째, 평가 및 피드백 후 교사에 의한 학생 개개인의 결과를 제시하도록 하였으며, 이를 통해 후속 학습에 도움이 되도록 하였다. 또한, 본 동기 모형을 초등학교 3학년 쓰기 활동에 적용하였다.

• 산업공학
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• 제4권2호
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• pp.25-34
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• 1991

The problem of scheduling the passage things with low transit priority to maximize the amonnt that can be sent during given time periods without interfering with the fixed schedule for passage things with high transit priority in a track, is treated in this paper. The problem is transformed into the Time Expanded Network without traverse time through the Ford and Fulkerson Model and the Enumeration Algorithm is developed for solutions using TENET GENerator(TENETGEN). Finally, the proposed algorithm is compared with Dinic's maximal-flow algorithm and examined for the availability of the procedures on the personal computer.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제6권2호
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• pp.55-64
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• 2002

According to changing the society rapidly in the 21s1 century, the self-regulated learning ability is considered as an ability of which people should carry on their lives. The purpose of this study was to investigate prospective elementary school teachers in mathematics teaching method class in terms of the following areas: (1) the degree of their abilities shown the lower level factors of motivated strategies for learning such as self-efficacy, intrinsic value, anxiety, cognitive strategy use, and self-regulation (2) relations between factors of motivated strategies for loaming and performance of prospective elementary school teachers The results show that the prospective elementary school teachers showed above the mean value of the motivated strategies for learning and there are positive relations among lower level factors of motivated strategies fur learning except anxiety, positive relation between motivated strategies for learning and achievement. In order to help the prospective elementary school teacher to improve their motivated strategies fur learning in their elementary mathematics teaching method lecture, several methods such as mathematical connections to real world problem, history of mathematics and interview with mathematicians and application of feller's ARCS model to elementary mathematics education are suggested.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.850-852
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• 1996

High impedance fault (HIF) is defined as fault that general overcurrent relay can't detect or interrupt, Especially when HIF occur under 15 kV, energized high voltage conductor results in fire hazard, equipment damage or personal threat. Because most HIF occur arc, HIF detection using arc is to increase. Numerical arc model can be applied in an electromagnetic transients program (EMTP) to reproduce the dynamic and random characteristic of arcs for any insulator arrangement, current and system voltage. It allows the representation of any network configuration to be investigated, so the digital simulation of arc faults through air can be substitute for demanding power arc test.

• 대한간호학회지
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• 제35권6호
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• pp.1113-1124
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• 2005

Purpose: The purpose of this study was to develop an e-Learning program about medication for nurses to enhance nurses' medication performance ability and to analyze learners' responses after studying with this program. Method: For the development of the e-Learning program, the NBISD(Network Based Instructional Systems Design) model, suggested by Jung(I999) was applied as a basic model and the instruction design theory of Gagne & Briggs(1979) and ARCS theory of Keller(I983) were applied. After the operation of this program for one month to 34 new nurses, learners' responses were analyzed. Result: Learners' knowledge of medication was greatly improved after this program. In addition learners' satisfaction with the overall education program, help in field applicability, ease of screen shift and exploration, and tutor activities were high and the contents were regarded suitable for e-Learning. Many things were advantageous such as easy accessibility, easy understandability with pictures and flash animation, practical cases and feedback from a tutor. Provision of a supplementary handout and improvement of a tight time schedule were pointed out as things to be improved. Conclusion: This e-Learning program can be used effectively for medication education for registered nurses, student nurses, and new nurses.