• Tribology and Lubricants
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• v.26 no.4
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• pp.219-223
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• 2010

Despite the increasing need of nanometer-scale accuracy in abrasive machining using ultrasmall particles such as abrasive jet and chemical mechanical polishing(CMP), the process mechanism is still unknown. Based on the background, research on the effects of various process parameters on the machined surface at abrasive machining was motivated and performed by using finite element analysis where the effect of slurry fluid flow involved. The effect of particle shape on the machined surface during particle-surface collision was discussed in this paper. The results from FEA simulation revealed that any damage or defect generation on machined surface by the impact may occur only if the particle has enough impact energy. Therefore, it could be concluded that generation of the defects and damage on the wafer surface after CMP process was mainly due to direct contact of the 3 bodies, i.e., pad-particle-wafer.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.2
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• pp.96-100
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• 2012

Existing, widely used industrial controller programmable logic controller (PLC) using the high cost and maintenance was a difficult problem. In addition, the network configuration was not easy. Thus, the filter press by remote control and management to improve productivity and shorten maintenance time. Variety of smart devices (smart phones, iPad, tablet PC, etc.) Remote control is possible by utilizing the existing controlled by the PLC addresses maintenance and improved performance compared to that of possible filter press control and management system was developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.769-772
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• 1995

Most turbo machines, which operate at high speeds, such as gas turbines, jet engines, pumps, and compressors are prone to perrturbing vibrations. The best vibration control method for rotors is to eliminate destabilizing factors. Careful balancing application of "more stable" oil-lubricated bearing, such as tilting pad bearings or use of anti-swirl devices in seals, are examplse of passive vibration control methods. the use of magnetic bearing is an active control method. An obvious advantage of active control is that it provides damping (or modifies system stiffness or other parameters) only when there is a need for that, i.e., in emergency states, while not affecting the rotor normal operational conditions. Moreover, active control methods provide exact position control through on-line control. In this study, a magnetic actuator, digital contrliier using DSP, and bipolar operational power supply/amplifiers were developed to show the effectiveness of reducing robot vibration. Also the curve fitting procedure to obtain the transfer function of frequency dependent component was developed. Results presented in this dissertation will provide a well-defined technical parameters in designing magnetic damper system.er system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.171-172
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• 2013

기존의 종이책은 다양한 스마트 모바일기기의 활발한 보급으로 인해 전용 단말기와 뷰어 앱(Veiwer App)을 통해 전자책(e-book)으로 서비스되고 있다. 최근에는 텍스트(Text) 중심의 전자책과 달리, 텍스트와 함께 동영상, 다양한 상호작용 요소를 중심으로 하는 앱북(App book)의 형태로 진화되고 있다. 아이패드(iPad)용 앱스토어(App Store)에서는 도서 관련 앱이 28%를 차지할 정도로 앱북 시장이 빠르게 성장함에도 불구하고, 여러 가지 전자책 전용 단말기, 뷰어 앱 UI(User Interface) 관련 연구들에 비해 앱북의 콘텐츠 및 UI에 대한 연구가 상대적으로 부족한 상황이다. 이에, 본 논문에서는 앱북 콘텐츠의 표시 방법에 따라 3개의 유형으로 분류하고, 대표 앱북을 선정하여, 콘텐츠의 객체 표시방법에 대해 분석하고, 상호작용 요소들을 분석하였다. 이를 통해, 객체 별 상호작용 요소를 고려한 전자잡지형 앱북의 콘텐츠 표시 방법 프레임워크를 설계하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.8
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• pp.1201-1210
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• 1990

This paper proposes on-chip instruction and data cache memories on RISC reduced instruction set computer) architecture which supports fast instruction fetch and data read/write, and enables RISC processor under research to obtain high performance. In the execution of HLL(high level language) programs, heavily used local scalar variables are stored in large register file, but arrays, structures, and global scalar variables are difficult for compiler to allocate registers. These problems can be solved by on-chip Instruction/Data cache. And each cycle of instruction fetch, pad delay causes the lowering of the processors's performance. Cache memories are designed in CMOS technology and SRAM(static-RAM), that saves layout area and power dissipation, is used for instruction and data storage. To speed up and support RISC processor's piplined architecture efficiently, hardwired logic technology is used overall circuits i cache blocks. The schematic capture and timing simulation of proposed cache memorises are performed on Apollo DN4000 workstation using Mentor Graphics CAD tools.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.213-214
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• 2011

스마트 기기 시장의 대중화와 수요가 증가함에 따라 다양한 종류의 애플리케이션이 사용자들의 일상생활에 큰 부분을 차지하고 있다. 더욱이 최근 iPad, Smart TV 등 다양한 기기와 스마트 기기와의 정보교환이 원활하게 이루어져 다양한 서비스가 제공되고 있다. 본 논문에서는 최근 많은 관심을 받고 있는 스마트 기기를 이용하여 특정 식당정보를 획득하고, 필요시 사용자가 메뉴 정보를 업데이트 할 수 있는 식당메뉴관리 애플리케이션을 개발한다. 이는 식당의 메뉴를 찾아가지 않고 스마트 기기를 활용하여 미리 파악하고, 해당 메뉴에 대한 맛 평가를 하여 보다 더 좋은 식단 메뉴를 선택 할 수 있게 한다. 안드로이드 운영체제를 이용하여 각각의 식당서버에 접속하여 메뉴를 검색하고, 각 음식에 대한 정보들을 공유 및 업데이트 할 수 있는 애플리케이션을 설계 및 구현하였다.

• International Journal of Contents
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• v.7 no.3
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• pp.38-47
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• 2011

The present research has created and evaluated contents capable of work appreciation visitors changing their viewpoints on their will by introducing mobile exhibition exposition devices (iPad) for large exhibition museum. Various exposition contents of usually invisible parts or those provided in accordance with user positions drew visitors' attentions and improved museum experience satisfaction. Utilization of digitalized exhibition information generated activeness in viewing and new communication between exhibition and a visitor instead of the conventional exhibition exposition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1517-1520
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• 2003

In this paper, we design a wedge type rail-clamp which can protect container crane from wind with constant clamping force regardless of the operating period. When we design wedge type rail clamp, it is important to determine the weight for locker to descent smoothly with an initial clamping force of rail and pad. Therefor, this paper suggest a process to decide a wright within proper range which could be obtained using FEA of wedge type rail clamp.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.90-96
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• 1998

There are various noises generated by friction. Among the rest, eliminating squeal noise generated during braking is an important task for the improvement of vehicle passengers' comfort. The parameters affecting brake squeal noise are the material properties of the braking pad, the dynamic properties of the brake parts and the dimensions of the brake assemble etc. Also, the squeal noise changes its inherent form(i.e. its sound pressure level and its frequency) with the normal load and sliding speed. In this study, the characteristics of brake squeal noise generated by friction is analyzed experimentally. The experiment focused on the analysis of friction self-excited vibrationand squeal noise level. Friction self-excited vibration is caused by the dry friction between pads and rotor, and occurs as a function of their relative sliding speeds. And Friction self-excited vibration is raised the brake squeal noise.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.873-878
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• 2000

Semiconductor packaging technology is changed rapidly according to the trends of the micro miniaturization of multimedia and information equipment. For I/O limitation and fine pitch limitation, DIP and SOP/QFP are replaced by BGA/CSP. This is one of the surface mount technology(SMT). Solder ball is bumped n the die pad and connected onto mounting board. In ball bump formation, vacuum suction type ball alignment process is widely used, However this type has some problems such as ionization, static electricity and difficulty of fifo(first-input first-out) of solder balls. Seesaw type is reducing these problems and has a structural simplicity and economic efficiency. Ball cartridge velocity and ball aligned plate angle are Important variables to improve the ball alignment Process. In this paper, seesaw-type CSP solder ball loader is developed and the optimal velocity and plate angle are proposed.