• Journal of Advanced Marine Engineering and Technology
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• v.15 no.3
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• pp.45-56
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• 1991

This paper describes characteristics of the flow pattern of the flow past a rectangular cylinder experimentally investigated. The width-to-length ratio of the section varried from 2 to4. For the statistical treatment, autocorrelation coefficient, probability density function and power spectral density function are obtained by the digital processing technic through on-line system with a hot wire anemometer. As a results, it was found that strong periodic coherent eddies structure is sustained to about 20H downstream from the cylinder. And nearer the cylinder in the wake, the number of turbulent eddies of a large scale coherent structure are comparatively much more dominant than that of a small scale one. By the analysis of power spectrum, It was cleared that there exists a certain range of the width to length ratio between 2.5 and 3 of which the flow pattern changes abruptly with a sudden discontinuity in Strouhal number.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1446-1454
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• 1990

A systematic method of design modification to reduce the influence of impact from multiple clearances in a planar four bar mechanism is developed. For this purpose, an optimization method is used with the objective function which is the linear sum of the Earles and Wu criteria for every joints with clearances. One coil spring is attached to a joint of limited range of revolution to reduce the undesirable dynamic effects due to clearances at joints. The stiffness of the coil spring and its pre-loading angle are chosen as design variables. A numerical example is taken for a four bar mechanism. The initial and modified mechanisms are compared using a clearance mechanism analysis technic to see the difference in dynamic effects due to contact loss. It is found that the modified mechanism produces much more smooth joint contact forces than the original design.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.448-453
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• 2003

This paper researched about technique of Opened CNC that were able to adapt themselves to rapid development of software and hardware. It is basic research what develop a scheme whereby technic make property. This paper theorized about to realize Opened CNC Software which is developing CNC Software flow from building Windows CE operating system's image that is possible realtime acting and multitasking. And Opened CNC Software's component designed independent classified modules. Classify Opened CNC Software's component which was consisted of basic OS Kernel, NC Code parser, Servo Motor Control, Software PLC, MMI(Man-Machine Interftce). And show there's functional example

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.592-596
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• 2001

A TACUB jig was applied to separate waste plastics [polystyrene (PS), acrylonitrile butadiene styrene (ABS), and polyethylene terephthalate (PET)] used in copy machine. The effect of water pulsation including amplitude and frequency on the separation performance was investigated for the feeds containing two or three plastics. Good results are obtained under suitable conditions. Grades of 99.8% PS,99.3% ABS, and 98.6% PET are recovered as the products in the upper, middle and bottom layers respectively. Based on these results, a processing plant fer recycling of plastics from scrapped copy machines is now under construction.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1216-1220
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• 2007

All the systems can be used properly for the original purpose when they can make the functions required for the users be concrete. Especially in the case that many technical systems are integrated like railroad systems, physically useful systems could be built if requirements analyses applying systems engineering and the process of functional design had to be supported. This paper is intended to review and present the measures and procedures to correctly supply the systems to users by giving systems manufactures and suppliers requirements in order to supply safe systems using safety analysis techniques named FHA(Functional Hazard Analysis) and Hazop Study.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.572-576
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• 2007

Railroad systems can be divided into the primary function for transporting passengers or freight and secondary function covering diverse environmental factors and interfaces. So, the most biggest and important reason and the goal of railroad systems is to satisfy the need for transportation based on the production and consumption of energy. Especially, the operation of safe systems is the inevitable element for achieving this objective. Performing this can be ultimately satisfied only when the relationship among operators, contractors, suppliers and assessors is established according to their missions. Therefore, we are trying to finding the way of approaching it systematically by reviewing which procedures and methodologies mission performers in various domains have to follow.

• Journal of Korean Society of Steel Construction
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• v.8 no.3 s.28
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• pp.47-54
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• 1996

Recently Sucessive progress in train technic has enabled us to constructed high-speed railways for ourselves. This caused more rapid train more pressure on a track and speedier track break-down. Especially in the construction of high-speed rails for high-speed traveling and safety accurate breaking distance is essential and not only computation of rolling resistance in theory but also verification through real measurement are important in basic material for breaking and starting load caused during the train running. In this study, we measured traveling resistance and calculated traveling resistance formula in the case of the SAEMA-EUL which consists of main part of current passenger trains and frights in this country.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.137-140
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• 1996

The deterioration of concrete due to alkali-aggregate reaction is dependent on the total alkali content per unit volume of concrete. It was reported that the expansion of high alkali concrete with the reactive aggregate increased easily due to high alkali of concrete with the reactive aggregate increased easily. And it has been confirmed that the addition of pozzolanic material prevents the concrete with reactive aggregate from deterioration caused by alkali-aggregate reaction. It is the aim of this study to provide the fundamental data on the possibility of alkali-aggregate reaction of high strength concrete and its preventing and repair technic.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.691-696
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• 1997

In recent years, stengthening of beam by steel plate, carbon fiber sheets, and carbon fiber laminate is spotlighted in order to repair and rehabilitation of R/C structures. In this study, 3 method of rehabilitation technic are analyzed from the tests. Test parameters are the width of cracks, the method of repair and rehabilitation, the magnitude of existing load. Deflection, failure load, strains of reinforcing bar, strains of sheet and plates are measured during tests. The failure mode and ultimate load are analyzed from these measured data. Test result shows that the width of cracks and the magnitude of existing load do not make any difference of ultimate flexural capacity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.879-884
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• 2012

Photoacoustic Tomography (PAT) is a promising medical imaging modality by reason of its particularity. It combines optical imaging contrast of optical imaging with the spatial resolution of ultrasound imaging and can demonstrate change of biological feature in an image. For that reason, many studies are in progress to apply this technic for diagnosis. But, real-time PAT system is necessary to confirm a biological reaction induced by external stimulation immediately. Thus, we developed a real-time PAT system using linear array transducer and self-developed Data acquisition board (DAQ) resources, To evaluate the feasibility and performance of our proposed system, two type of phantom test were also performed. As a result of those experiments, the proposed system shows enough performance and confirm its usefulness.