• Journal of Drive and Control
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• v.9 no.1
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• pp.18-24
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• 2012

The paper deals with the design of a new low-friction seal for a pneumatic cylinder with high speed actuation. The seal performance with variation of the cross sections in piston seals with elastomeric material was investigated to minimize the friction forces using ABAQUS. The contact stress and strain distributions and frictional forces of the piston seals were investigated with variation of interference fits, supply pressures and friction coefficients. To develop adequate and productive procedures, the finite element models of the piston seals were created and nonlinear analysis of a seal design was conducted in order to build further knowledge and understanding of the seal's performance characteristics.

• Journal of Drive and Control
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• v.10 no.3
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• pp.7-13
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• 2013

Hydraulic vane pumps are widely used in various hydraulic systems because of its compactness and light weight. It is well known that the vanes and cam ring are separated by very thin liquid films which result in the EHL state. Contrary to the case of cylindrical roller bearings, the inlet and side boundary pressures are much higher than the atmospheric pressure. In this paper, a numerical solution of the EHL of finite line contacts between the cam ring and vane tip with profiled ends is presented. Using a finite difference method with non-uniform grids and the Newton-Raphson method, converged solutions are obtained for moderate load and material parameters. The EHL pressure distribution and film shape are considerably affected by pump delivery pressure and the side boundary condition applied. Both the maximum pressure and the minimum film thickness always occurred near the edge regions. The present results can be used in the design of optimum vane profile in hydraulic vane pump.

• Knowledge Management Research
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• v.19 no.1
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• pp.119-132
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• 2018

Many advanced products and services are emerging in the market thanks to data-based technologies such as Internet (IoT), Big Data, and AI. The construction of a system for data processing under the IoT network environment is not simple in configuration, and has a lot of restrictions due to a high cost for constructing a high performance server environment. Therefore, in this paper, we will design a development environment for large data analysis computing platform using open source with low cost and practicality. Therefore, this study intends to implement a big data processing system using Raspberry Pi, an ultra-small PC environment, and open source API. This big data processing system includes building a portable server system, building a web server for web mining, developing Python IDE classes for crawling, and developing R Libraries for NLP and visualization. Through this research, we will develop a web environment that can control real-time data collection and analysis of web media in a mobile environment and present it as a curriculum for non-IT specialists.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1442-1447
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• 2003

Computer is a very powerful machine which is widely using for data processing, DB construction, peripheral device control, image processing etc. Consequently, many researches and developments have progressed for high performance processing unit, and other devices. Especially, the core units such as semiconductor parts are rapidly growing so that high-integration, high-performance, microminiat turization is possible. The packaging in the semiconductor industry is very important technique to de determine the performance of the system that the semiconductor is used. In this paper, the inspection of the inner defects such as delamination, void, crack, etc. in the semiconductor packages is studied. ESPI which is a non-contact, non-destructive, and full-field inspection method is used for the inner defect inspection and its results are compared with that of C-Scan method.

• Water Engineering Research
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• v.4 no.4
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• pp.187-192
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• 2003

The rainfall observation systems have largely been improved in Japan. The Japan Meteorological Agency, prefecture governments, and other administrative bodies have also increased the number of rain gauges thru out the country. The density of observatories is now one per several $\km^2$. Heavy rainfall information systems have been improved. Besides it, the Internet was popularized in the late 1990s, and has been used to transmit data of heavy rainfall. Internet accessible cellular phones have been popular in Japan since 1999. Such phones are expected to be useful in the field of disaster warning announcements, because they can automatically notify users bye-mail of pending disasters. The use of the Internet during natural disasters is groundbreaking in Japan today. However, in order to use disaster information effectively on Internet it is necessary to investigate how to use the information during the rainfall disaster. Therefore in our study we suggest methods on the effective construction and their use of information technology on Internet.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.918-919
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• 2012

This paper present a method of function decomposition and input variable manipulation method based on modular design techniques. We obtain the column multiplicity of decomposition function according to row decomposition method. Also, the proposed partial decomposition function have advantage which is able to omit control function using t-Gate. We find the advantage for internal connection decrement 12% and T-gate number 16%, therefore we find the simple design circuit.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.11-15
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• 2002

Switched Reluctance Motor (SRM) offers the advantages of simple and robust motor construction, high speeds and high efficiencies over a wide operating range of torque and speed, excellent controllability. However, SRM has the disadvantages of high current harmonics, and low power factor because of a capacitor filter is inserted in the power converter and inductance of SRM is high, it has pulse waveform of current. This paper deals with an energy efficient converter fed SRM system with the reduced harmonics and improved power factor and with higher efficiency. The validity of the proposed scheme is verified via experiment. We are implemented the proposed control system using 80C196KC micro-controller.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.369-373
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• 2001

In this paper, we proposes the steps adopted to construct the neural network model for GMAW welds. Conventional, automated process generally involves sophisticated sensing and control techniques applied to various processing parameters. Welding parameters are influenced by numerous factors, such as welding current, arc voltage, torch travel speed, electrode condition and shielding gas type and flow rate etc. In traditional work, the structural mathematical models have been used to represent this relationship. Contrary to the traditional model method, neural network models are based on non-parametric modeling techniques. For the welding process modeling, the non-linearity at well as the coupled input characteristics makes it apparent that the neural network is probably the most suitable candidate for this task. Finally, a suitable proposal to improve the construction of the model has also been presented in the paper.

• Annual Conference of KIPS
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• 2003.11b
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• pp.975-978
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• 2003

초고속 통신망의 발달과 개인 컴퓨터의 고급화가 이루어지면서 분산 환경에서 네트워크에 연결된 이런 고급화된 컴퓨터들의 유휴자원을 이용하여 대규모의 데이터를 처리하기 위한 연구와 기존의 클라이언트-서버 환경에서의 부하를 각 컴퓨터들에게 분산시키는 연구가 활발하게 진행되고 있다. 본 논문에서는 Peer-to-Peer환경에서 메시지 제어를 위한 mesh 기반의 네트워크를 구성하고 Gossip 프로토콜을 이용한 각 peer간의 효율적인 메시지 전송 기법을 제안한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.6
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• pp.316-321
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• 1999

Disk type single phase switched reluctance motor which is a simple robust construction, simple control circuit and low manufacturing cost, has a characteristics of axial and radial flux machines. However, because this DSPSRM has a complicated magnetic circuit, it is difficult to analyze the design characteristics.. In this study, the calculation of design parameter based on the conventional design theory of electric machine and the characteristics analysis by computer simulation was performed. As the DSPSRM has the characteristics of both AFM and RFM, it is difficult to analyze its characteristics by the 2D FEM. 3D FEM was applied in the analysis of energy distribution and approximated calculation of torque characteristics with rotor positions. With analysis results, prototype of DSPSRM is manufactured.