• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권2호
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• pp.136-144
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• 2014

The existing conventional motion controller does not perform well in the presence of nonlinear properties, uncertain factors, and servo lag phenomena of industrial actuators. Hence, a feasible and effective fuzzy self-tuning proportional integral derivative (PID) and feed-forward control scheme is introduced to overcome these problems. In this design, a fuzzy tuner is used to tune the PID parameters resulting in the rejection of the disturbance, which achieves better performance. Then, both velocity and acceleration feed-forward units are added to considerably reduce the tracking error due to servo lag. To verify the capability and effectiveness of the proposed control scheme, the hardware configuration includes digital signal processing (DSP) which plays the main role, dual-port RAM (DPRAM) to guarantee rapid and reliable communication with the host, field-programmable gate array (FPGA) to handle the task of the address decoder and receive the feed-back encoder signal, and several peripheral logic circuits. The results from the experiments show that the proposed motion controller has a smooth profile, with high tracking precision and real-time performance, which are applicable in various manufacturing fields.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.27-33
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• 2004

Electro-theological fluid is recently used for the micro polishing of 3-dimensional micro-aspherical lens. It's also used for polishing small area defects on the wide flat wafer. Since ER fluid shows a behavior of viscosity changing under certain electric fields. micro polishing efficiency may be enhanced for certain cases. In this paper, a perfluorinated carbonyl fluoride oil based ER fluids was used to improve surface polishing rate and submicron-scale accuracy. As the polishing electrodes, micro size cylindrical tools had been used for maximizing the electric field. An experimental device, which was applied for micro polishing a number of wafers of 4inches in size and other workpiece. was made on a precision polishing system. It consisted of a steel electrode. a wafer fixture. l0㎃ current and DC 5㎸ power supply unit, and a controller unit. From the Experiments. the ER fluid is applicable for micro polishing of small parts.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.611-613
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• 2000

Rotor eccentricity exists extensively in BLDC motors because of manufacturing imprecision or bearing defects. In this paper, magnetic fields of a BLDC motor with static rotor eccentricity are analyzed by the time- stepping finite element method. Torque ripple, cogging torque, winding current, counter-em! and unbalanced magnetic force characteristics are obtained. These results are compared with those of a non-eccentric BLDC motor.

• International journal of advanced smart convergence
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• 제4권2호
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• pp.124-130
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• 2015

Infinite competition on ICT industries is starting again. The basis of competence over global dominance will be human resource, a global ecosystem for products and national agenda for science and technology, etc.. This paper presents the six solution for the Global Competitiveness and Coexistence of Korean ICT Industries. Korea should nurture the brand of "World Best Korean ICT Forever" to secure technical competency of ICT related fields in global market. All ICT technologies should be aligned to global standard and market demand from beginning and the ecosystem around product needs to be established. System framework for utilizing the resource of core SW experts must be established. Through global partnership with China as manufacturing base for Korea-developed products, technical competency can be maintained including product planning. Security measure for technical assets is mandatory. Finally, core technology that will drive the future of ICT industries in Korea should be regarded as core subjects.

• 로봇학회논문지
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• 제17권2호
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• pp.230-237
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• 2022

A technology that allows users to feel the elasticity of fabric through force feedback in the fashion and textile fields is very helpful to related manufacturing and sales areas. Currently bundle of fabrics, so called Swatch, is the only available way for the designer, manufacturer and the end-user to feel the fabrics. Images and video clips provide only visual characteristics, hence touch and stiffness are also very important characteristics to check beforehand. A study is conducted on a haptic device, which estimates the amount of change in the length of the virtual fabric and generates resistive force so that the user could feel the fabric stiffness. Since cables that can only transmit the tensile force are used, a force realization method is proposed, and it is verified numerically and experimentally.

• 연구논문집
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• 통권25호
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• pp.91-98
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• 1995

Recently, improving the energy efficiency of a pneumatic system and reducing the consumption of compressed air were a concern of scholars at domestic and abroad. The using fields of a pneumatic system are widely used in factory automation of manufacturing line, chemical factories with explosiveness danger and petroleum industries etc. In particular, pneumatic cylinder is applied to feeding work of workpiece. jig tools and press mechanism, reciprocation and rotary motion with rack and pinion. In this study, the experimental apparatus consisted to pneumatic cylinder, dual supply pressure regulator and solenoid valve. The dual supply pressure regulator connected to outlet port of solenoid valve. The supply pressure($4.5kg_f/cm^2$) of compressed air goes into the rodless chamber 1 to drive the piston rod forward which is named working stage. The supply pressure ($2kg_f/cm^2$) of compressed air goes into the rod chamber 2 to drive the piston rod backward which is named no-working stage. Accordingly, the research results of this study can be obtained to Energy-Saving Effects of the compressed air about 35%.

• 한국통신학회논문지
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• 제37권1C호
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• pp.17-23
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• 2012

RFID(Radio Frequency IDentification)는 바코드를 대체해 많은 분야에서 각광을 받고 있으나, 현재까지는 적용 범위가 유통관리, 판매 등의 한정된 산업 분야에서 주로 이용되어 왔다. 본 논문에서는 RFID 시스템을 실제 공정과정에 적용할 경우의 운영 방안 및 효과에 대한 연구 결과를 기술하였다. 아울러 RFID 시스템의 도입 전과 후의 비용 관점에서의 비교 분석 결과, RFID 시스템의 운용 이후 이에 투자되는 비용 상쇄는 물론 그 이상의 효과가 있음을 확인 하였다. 따라서 본 연구 결과는 바코드 시스템에서 RFID 시스템으로의 교체를 망설이는 많은 제조업체들의 의사결정에 크게 기여할 수 있을 것으로 기대된다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.494-497
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• 2002

본 연구의 목적은 효과적인 건설안전경영시스템의 구축을 위한 표준모델을 제시하는데 있다. 연구의 진행은 문헌을 통한 이론적 고찰과 기존의 품질 및 환경시스템에 관한 현황조사를 통하여 이루어졌다. 이와 같은 과정을 통하여 도출된 결론을 요약하면 다음과 같다. 기존의 품질 및 환경시스템에 관한 현황조사 결과, 효과적인 건설안전경영시스템의 구축에 있어 성과측정 및 보고시스템 체계의 정립이 필요한 것으로 분석되었다. 따라서 기존 시스템에 대한 보완과 GMP(Good Management Practice)의 적용을 중심으로 한 총 여섯 단계의 사전적 안전경영시스템의 표준모델을 제시하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.639-640
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• 2006

Many companies in mechanical engineering fields have accumulated information of design and manufacturing. The Enterprise Resource Planning (ERP) and Product Data Management (PDM) systems help information gathering and data managing. However, these systems are not flexible to support suitable functionality for specific product because these systems deal with entire enterprise resources. To cope with this issue, a web-based design support system was constructed for the design process of automotive steel pulley. This system provided 1) search service for part design with key word and clustering map, and 2) estimation service of maximum stress. These services reduced design time by reducing iterative jobs with Computer Aided Design (CAD) and Computer Aided Engineering (CAE) for stress analysis, and by enhancing search for existing data of steel pulley.

• 한국시뮬레이션학회논문지
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• 제14권3호
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• pp.91-100
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• 2005

Grid computing is widely applicable to various fields of industry including process control and manufacturing, military command and control, transportation management, and so on. In a viewpoint of application area, grid computing can be classified to three aspects that are computational grid, data grid and access grid. This paper focuses on computational grid which handles complex and large-scale computing problems. Computational grid is characterized by system dynamics which handles a variety of processors and jobs on continuous time. To solve problems of system complexity and reliability due to complex system dynamics, computational grid needs scheduling policies that allocate various jobs to proper processors and decide processing orders of allocated jobs. This paper proposes a service prediction-based job scheduling model and present its scheduling algorithm that is applicable for computational grid. The service prediction-based job scheduling model can minimize overall system execution time since the model predicts the next processing time of each processing component and distributes a job to a processing component with minimum processing time. This paper implements the job scheduling model on the DEVS modeling and simulation environment and evaluates its efficiency and reliability. Empirical results, which are compared to conventional scheduling policies, show the usefulness of service prediction-based job scheduling.