• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.3
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• pp.157-162
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• 2012

In this paper, we propose a flight data storing system for effective data processing. Since the flight data contains critical information and their sizes are vast, encryption and compression would be needed to manage the flight data in effect. And we implemented the flight data storing system using an embedded board with DSP based on DPCM compression and AES encryption. Especially, we applied the reordering technique to advance the security function. From the simulations for two type data of voice and avionics, we found the developed system is well performed.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.3
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• pp.63-67
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• 1994

A main property for fiber reinforced thermoplastic composite material in compression molding is the flow of fibers. This flow is so effective a long direction of acting force that this study examined for the inclined angel of 30$^{\circ}$, 45$^{\circ}$ and 6$^{\circ}$. Below the near softing temperature of plastic, the fiber has been fractured at a point so that the fiber strength is smaller then the local hydrostatic stress in the mold. It has been found that the position of fracture is changing accrding to the incling angle. In case of the above softing temperature, the larger the inclined is, the farther the flow of fiber move. Also the plastic flow has been progresed with the cicular are type.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.371-379
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• 1993

The wrinkling in the electromagnetic tube compression with a mandrel is remarkably smaller than that of the process without it. To analyze this phenomenon, the critical forming parameters such as the ratio of the clearance to the shell radius, the ratio of the thickness to the shell radius, and the ratio of the applied pressure to the standard pressure are introduced tp consider the effect of the mandrel, in addition to those of the thickness of shell and applied loads. The amplification ratio is also used to observe the magnitude of amplification. The results obtained by 2-D finite element method show that the initial imperfection embedded in the radius of cylindrical shell is the dominant factor to determine the final shape of the tube compression, and that the amplification ratio tends to have smaller values with the smaller clearance ratio and also with the larger thickness and pressure ratios.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2071-2075
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• 2003

Pressure variation is one of the major sources on noise emission in the oil hydraulic piston pumps. Therefore, it is necessary to clarify about pressure variation characteristics of the oil hydraulic piston pumps to reduce noise. Pressure variations in a cylinder at trapping region were measured during pump working period with discharge pressures, rotational speeds. The effect of pre-compression of the discharge port with three types valve plates also investigated. It was found that the pressure variation characteristics of oil hydraulic piston pumps deeply related with pre-compression design of the discharge port. Also, it was found that the pressure overshoot at trapping region can reduce by use of pre-compression at the end of the discharge port in valve plate

• Journal of the Korean Society for Precision Engineering
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• v.14 no.8
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• pp.82-91
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• 1997

The major objective of this study is to establish analytical technique in order to analyze the behaviour of semi-solid material considering induction heating of the billet. Induction heating process is analyzed by using commerical finite element software. ANSYS. The finite element program, SFAC2D, for the simulation of deformation in semi-solid state is developed in the present study. The semi-solid behaviour is described by a viscoplastic model for the solid phase, and by the Darcy's law for the liquid flow. Simple compression and closed-die compression process considering induction heating are analyzed, and also it is found that the distribution of initial solid fraction of the billet has an important effect on deformation behaviour of semi-solid material. In order to verify the effectiveness of proposed analytical technique the simulation result is compared with experimental result.

• The Journal of Korea CHUNA Manual Medicine
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• v.6 no.1
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• pp.147-156
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• 2005

Objective : The objective of this study is to evaluate the treatment effect of Band training in Osteoporotic Compression Fracture. Methods : Band training, Herb medicine and Acupuncture were performed for 56days admission in a patient who had Osteoporotic Compression Fracture. Result : ROM of Lumbar, Milgram test and Dorsiflexion has improved. VAS and ODI score were also decreased.

• Transactions of Materials Processing
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• v.26 no.6
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• pp.333-340
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• 2017

The cyclic hardening behavior of transformation-induced plasticity (TRIP) steels shows tension-compression asymmetry known to be attributed to transformation of retained austenite into martensite during deformation. In this work, YoshidaUemori hardening model was used to represent the asymmetric hardening behavior of TRIP1180 steel. Yoshida-Uemori hardening model parameters were obtained from three sets of data: tension-compression, compression-tension, and a combination of the two. Material models were validated for U-bending and springback.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.2
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• pp.17-23
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• 2004

The effects of refining consistency and plate gap on the specific energy consumption and physical properties of liner were investigated. Higher refining consistency and narrower plate gap brought about the reduction of specific energy consumption to decrease the freeness. Refining consistency and plate gap did not affect the bulk, Taber stiffness and compression index. The reduction of freeness and/or the increase of specific energy consumption caused the decrease of bulk and Taber stiffness, but increased the compression index. The effect of grammage on bulk was not observed, but Taber stiffness and compression index were increased with grammage. The bulk was decreased with the reduction of freeness rapidly at the above 400 mL CSF, and then levelled off. It is expected that the reduction of energy consumption could be obtained from the application of higher refining consistency and narrower plate gap during refining.

• Korea-Australia Rheology Journal
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• v.18 no.4
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• pp.183-189
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• 2006

High internal phase emulsions are highly concentrated emulsion systems consisting of a large volume of dispersed phase above 0.74. The rheological properties of high internal phase water-in-oil emulsions were measured conducting steady shear, oscillatory shear and creep/recovery experiments. It was found that the yield stress is inversely proportional to the drop size with the exponent of values between 1 and 2. Since the oil phase contains monomeric species, microcellular foams can easily be prepared from high internal phase emulsions. In this study, the microcellular foams combining a couple of thickeners into the conventional formulation of styrene and water system were investigated to understand the effect of viscosity ratio on cell size. Cell size variation on thickener concentration could be explained by a dimensional analysis between the capillary number and the viscosity ratio. Compression properties of foam are important end use properties in many practical applications. Crush strength and Young's modulus of microcellular foams polymerized from high internal phase emulsions were measured and compared from compression tests. Of the foams tested in this study, the foam prepared from the organoclay having reactive group as an oil phase thickener showed outstanding compression properties.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.66-72
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• 2002

A premixed charge compression ignition engine is experimentally investigated for the reduction of NOx and smoke emissions from diesel engines. In this study, the premixed fuel is injected into the intake manifold to form homogeneous pre-mixture in the combustion chamber and then this pre-mixture is ignited by small amount of diesel fuel directly injected into the cylinder. In the premixed charge compression ignition engine, NOx and smoke concentrations of the exhaust emissions were reduced simultaneously as compared with the conventional diesel engine. But HC emission was increased with the increase of premixed ratio. Also, when EGR system was applied to the PCCI diesel engine, the effect of EGR rate on the combustion characteristics and the exhaust gas emissions was discussed.