• 실천공학교육논문지
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• 제11권1호
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• pp.51-59
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• 2019

대학연계형 일학습병행제를 운영하는 계약학과 입장에서 NCS기반자격과 과정평가형 자격 모두를 수용할 수 있는 교과 편성이 가능한가에 대한 연구로 두 자격 간 주요내용과 차이점을 비교 분석한다. 기계설계 직무중에서 과정평가형 자격으로 공고된 기계설계기사 사례 분석을 통하여 양측 자격의 편성 기준에 부합하는 교과과정을 개발하였고 향후 운영상의 문제점을 예측하고 극복방안을 제시한다. 또한 일학습병행제와 과정평가형을 연계하여 운영하는 전문 교육기관으로 공급자 중심의 교육훈련과 수요자 중심 기술 자격의 격차를 최소화하고 학습근로자의 학업 성과를 극대화 하기 위한 현장주도 교육과정 편성이 용이하도록 몇가지 방안을 제안한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.346-349
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• 1996

In this paper development of a CAD of control systems is introduced which enables us to do not only analysis of control systems, design of controllers but also real-time implementation of controllers. By utilizing this software, the control engineer is able to repeat the procedure of modification of controllers and experiments without recompile to attain better performance. The software also offers the facility to update the parameters of controllers without stopping real-time control, which helps on-line tuning of controllers. If some parameters of the controller is changed on-line, the control input may change discontinuously. It has serious effect on the control systems. A method for on-line tuning of state feedback controller with state observer is proposed and verified through the experiment with an inverted pendulum.

• 산업기술연구
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• 제25권B호
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• pp.141-147
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• 2005

A target of this paper is to get some elementary experimental data on the energy harvesting using a piezoelectric material. A THUNDER series piezo material (TH7-R), which has been developed by NASA engineer is selected for this study. In order to provide a mechanical energy to the piezoelectric material, a mechanical motion vibrator and its driving electronics are designed. Using a simple PWM control, the excitation frequency of vibrating mechanical motion is varied. The generated electric power as a function of the excitation frequency is monitored and analyzed. This initial experiment shows a possible energy source using a piezoelectric material for the application to low-power consumed small electronic devices such as RFID, MEMS, and etc.

• 한국정밀공학회지
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• 제23권6호
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• pp.64-71
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• 2006

A target of this paper is to study on the usefulness of the adaptive piezoelectric energy harvesting device as a wireless electrical power supply when it is driven by mechanical vibrations of low frequency. For this purpose, an adaptive control technique and a step-down converter are used. A THUNDER series a piezoelectric material (TH7-R), which has been developed by a NASA engineer is selected for this study. In order to provide a mechanical energy to the piezoelectric material, a mechanical motion vibrator is designed. The adaptive controller is implemented using a dSPACE DS1104 controller board. The do-dc converter with an adaptive control technique harvests energy at over five times the rate of direct charging without a converter.

• Journal of Mechanical Science and Technology
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• 제17권11호
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• pp.1725-1731
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• 2003

A high level CVT ratio control algorithm is proposed to improve the engine performance by considering the powertrain response lag. In this algorithm, the desired CVT speed ratio is modified from the vehicle velocity, which is estimated after the time delay due to the powertrain response lag. In addition, the acceleration map is constructed to estimate the vehicle acceleration from the throttle pedal position and the CVT ratio. Using the CVT ratio control algorithm and the acceleration map, vehicle performance simulations are performed to evaluate the engine performance and fuel economy. It is found that the fuel economy can be improved about 3.6% for FUDS by the ratio control algorithm for the target vehicle. In selecting the appropriate time delay, compromise between the fuel economy and the acceleration performance is required.

• 공학교육연구
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• 제14권5호
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• pp.37-45
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• 2011

This paper suggests a reinterpretation on Calvert's thesis of the conflict between "shop culture" and "school culture". Robert H. Thurston, who Calvert portraited as the proponent of school culture, was a man from shop culture and the shop culuture's old boy network was essential for Thurston's many achievements as an engineer and educater. This reinterpretation based on the narrowing the scope of the American mechanical engineers in the 19th century into those who shared and inherited the social recognition as the leading machinists from the social upper strata machinist such as the Stevens via machine tool makers of the mid century.

• 한국정밀공학회지
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• 제25권6호
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• pp.92-98
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• 2008

The target of this paper is to study on the usefulness of the SSHI technique as a wireless electrical power supply when it is driven by mechanical vibrations of low frequency. A THUNDER series a piezoelectric material (TH7-R), which has been developed by a NASA engineer is selected for this study. A mechanical motion vibrator supplies piezoelectric material with mechanical energy. An optical fiber sensor and a pulse generating circuit are used to accomplish the parallel-SSHI technique. As a result of this study, energy harvesting using SSHI technique results in a significant increase of the electrical power flow.

• Advances in materials Research
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• 제12권4호
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• pp.273-286
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• 2023

The fracture mechanics make it possible to characterize the behavior with cracking of structures using parameters quantifiable in the sense of the engineer, in particular the stress field, the size of the crack, and the resistance to cracking of the material. Any structure contains defects, whether they were introduced during the production of the part (machining or molding defects for example). The aim of this work is to determine numerically by the finite element method the stress concentration factor Kt of a plate subjected to a tensile loading containing a lateral form defect with different sizes: a semicircle of different radii, a notch with different opening angles and a crack of different lengths. The crack propagation is then determined using the extended finite element technique (X-FEM). The modeling was carried out using the ABAQUS calculation code.

• 한국생산제조학회지
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• 제22권3_1spc호
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• pp.509-517
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• 2013

This paper presents upgraded equipment to assist a patient in rehabilitating of their knee-joint by themselves. A new automatic mechanism is suggested and developed in order to add functions for enforcing the leg muscles, which were absent in previous rehabilitation machines. Using the Pro-engineer software, we analyze the displacements and speeds of several moving points of the equipment during various planned exercises. In addition, an appropriate control panel for operation is developed. Three motors andthree motor drivers are used in a tilting part for the ankle joint, sliding guide part for the knee joint, and up-down moving part for the whole leg. Finally, various newly upgraded motions can be generated by controlling the three motors simultaneously. we show that by using this equipment, we can adjust the proper length of the equipment according to the user's height and the intensity of the rehabilitation exercise.

• 한국전자거래학회지
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• 제1권2호
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• pp.93-116
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• 1996

Nowadays, there are many efforts to integrate CAD/CAM and other systems. The key of integration is engineering database implementation through the product data definition. In this paper, we suggest the product data definition and their properties for electronic consumer product throughout the requirement analysis for engineering database. Electronic consumer products include electric/electronic parts. as well as mechanical part which mainly compose of machinery. The paper is composed of three parts: the first is analysis about engineering data base. the second is understanding of product data structure and properties. and the last is modeling of product data including static and dynamic characteristics.