• Transactions of the Korean Society of Machine Tool Engineers
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• 제13권5호
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• pp.38-48
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• 2004

Recently the use of high-speed equipment in machine-tool industry has greatly increased, which requires the development of prognostics and prediction methods on the design stage. Conversion of the test/experiments stage from real to virtual reality will not only significantly reduce the design and manufacturing cost, but will also increase design quality. This paper shows how it is possible to develop the automated system for the design calculations of the air-bearing spindles. First, the general calculation method is introduced. It contains several steps, namely, geometry identification, pressure calculation, stiffiness calculation, dynamics characteristics calculation. For geometry identification reducing spindle shaft to rings was proposed, which helps to automate the calculation process. For pressure calculation the Peshti method was implemented. For stiffiness calculation the analysis was made, which shown the necessity of correct calculation step selection. Then the system of ordinary differential equations containing influence coefficients was evolved, which is used for trjectories calculation. The graphical representation of the calculation results shows the dynamic behavior of the spindle unit concerning various working conditions. Finally, this automated system is illustrated by an example of the air-bearing spindle calculation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 1991년도 추계학술대회 논문집
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• pp.67-71
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• 1991

최근 기계가공의 고능률화와 고정도화를 위하여 공작기계의 고속화의 요구가 해가 갈수록 높아지고 있다. 특히 터어닝센타(Turning Center)에 있어서도 주축회전수가 1만 rpm 정도의 고속화, 고출력화와 함께 공구의 고속, 중점삭을 향한 성능향상이 진전되어가고 있으나, 기계-공작물-공구의 절삭 시스템 중에서 기계와 공작물을 연결하는 인터페이스로서, 고속화된 척의 개발이 늦어져서 기계의 고속화를 저해하는 하나의 요인으로 지적되어 지고 있다.(중략)

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.714-719
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• 2000

This paper describes a transfer matrix approach to analyze the dynamics of a high sped flexible rotor system supported at 2 positions by five ceramic bearings. The rotor system is modelled as lumped parameters in which many factors are considered not only lumped inertia or mass, bending moment, shear force but also gyroscopic effect and unbalance. The equation of motion is derived in the transfer matrix form, from which the eigenvalues equation is also derived. The transfer natural frequencies and modes. The eigenvalues, eigenmodes, campbell diagram, whirling critical speed, whirling modes, and the response of unbalance are calculated and discussed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.27-33
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• 1999

In order to regulate cutting force at a desired level during NC lathe process, a feedrate override Adaptive Control Constraint system was developed. Nonlinear model of the cutting process was linearized as an adaptive model with a time varing process parameter. Performance of the ACC system was confirmed on the NC lathe equipped with the developed NC system through a large amount of experiment.

• 한국기계연구소 소보
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• 통권20호
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• pp.21-26
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• 1990

In order to satisfy the industrial requirements to measure the rotational error motion of main spindles and to find out the source of the error motion, some measuring systems were made. Their measuring principle are based on the 3-point roundness measurement. In these measuring systems, the measurements are processed by digital calculation technique and the form error and the rotational error motion of main spindles are spearated. In the present paper, the principle of 3-point metnod is introduced and some application examples are shown.

• Resources Recycling
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• 제13권4호
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• pp.46-52
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• 2004

The present main research direction of waste treatment is the development of incineration system for low pollution. Also, heat value of waste is increased because of the rising of living standard, environmental consideration and collection of sorted waste for recycling. Therefore, many researches have been continued for solving ash problem including heavy metals, dioxin problem and high energy efficiency by use of high heat value. This study is described for the facilities of pyrolysis system, pyrolysis-melting system, pyrolysis-gasification melting system.

• Journal of Korean Society for Quality Management
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• 제23권1호
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• pp.127-141
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• 1995

대용량 ISDN(Integrated Services Digital Network)용 전전자 교환기 TDX-10 연구개발 사업의 궁극적 목적은 미래 통신망이 요구하는 다양한 음성 및 비음성 정보통신 서비스를 제공하고 정보의 교환, 가공, 축적 및 처리에 고도의 융통성을 부여할 수 있는 국내표준 전전자 교환기를 개발하여 통신투자의 경제적 통신운영기술 자립화를 달성하는데 있다. 현재 대용량 전전자 교환기인 TDX-10 ISDN의 상용화 단계의 마무리 업무가 진행중이며, 통신서비스의 다양화, 광대역화, 고속화를 위한 광대역통신망의 주축이 되는 ATM교환기가 개발중에 있다. 본 고에서는 TDX-10 ISDN 시스템개발단계에서 구현된 시스템 시험수행 과정 및 평가작업을 토대로한 체계적이며 전략적인 품질보증 활동에 관해 기술하였으며, 신뢰성 있는 시험결과를 도출할 수 있는 다양한 시험관리 기법과 그 결과를 분석하고 차후 시험 및 보완작업을 위한 제반 활동체계가 소개된다.

• Proceedings of the KIEE Conference
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1138-1139
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• 2006

철도에 있어서 주행중인 열차와 지상간의 열차무선통신네트워크는 종래의 음성통화를 주축으로 하는 열차무선의 기능에 더하여, 차량상태 정보나 동영상 정보의 차량-지상간 양방향 전송을 비롯하여, 무선통신기반 열차제어시스템(CBTC : Communication Based Train Control System) 등에 확대 응용되면서 그 중요성은 점점 더 증가하고 있는 추세에 있다. 이에 따라, 향후 시스템의 발전에 따라 통화 채널의 증가, 데이터 통신 등을 가능하게 하는 새로운 시스템의 구축이 필요할 것으로 기대된다. 따라서 본 논문에서는 철도 연선에 있어서의 열차와 지상 무선통신기지 간의 효과적인 핸드오프기법에 대하여 검토를 수행하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.116-122
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• 2004

The HF band communication of roast radio station had operated with principal axis of maritime communication until early in the 1990. But, that is changed with development of data communication and satellite technique, which have operated a few by rapidly decrement of user with accomplishment of the GMDSS. Recently, the radio system of 11u band is expanded to globe maritime communication, which is support to maritime safety information and data traffic service by low charge with the SSB high speed modem. This study have proposed the digitalize method for maritime communication system using HF band in domestic.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.833-835
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• 2010

The SPARTAN-3E development kit is equipped with an FPGA which holds 500 thousand logic gates and a bus system platform using MicroBlaze microprocessor system. This kind of embedded systems can be used to gather information from sensor nodes and send over to the main server periodically through the network gateway, using the microprocessor-based embedded system, so that edlers living alone under sensor coverage can send their moving information and can be applied to get help in the event of emergency situations. In this paper, we designed a simple embedded system based on a CPU and flash memories using such FPGAs which can be used to monitor those elderlies living alone. The developed hardware system can be directly combined with the web-based elders-living-alone monitoring system, making the system more efficient.