• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.97-104
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• 2004

This paper proposes an efficient VLSI architecture of 9-7/5-3 Lifting DWT filters that is used by lossy or lossless compression of JPEG2000. The proposed architecture uses only internal line memories to compute Lifting-DWT operations and its PE(Processing Element) has critical path with 1 multiplier and 1 adder. To reduce the number of PE, we make the vertical filter that is responsible for the column operations of the first level perform both the row and column operations of the second and following levels. As a result, the architecture has smaller hardware cost compared to that of other architectures. It was modeled in RTL level using VHDL and implemented on Altera APEX 20K FPGA.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1224-1227
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• 2006

It has been recognized unsaturated soil behaviour playing an important role in geomechanics. Up to now, only a few experimental data are available for the technical difficulties related to both volume changes and suction measurements. In this study, the volume changes of unsaturated compacted silty soil were monitored with proximeter (i.e. non-contactable transducer) during various triaxial compression tests, which gave a realistic estimation in the volume changes of unsaturated soil sample. The measurement of volume changes were performed with 0.5% of the maximum error under the axial strain ratio of less than 10%. The experimental results have revealed that the mechanical behaviour of unsaturated soil can be significantly affected by the matric suction. During the shearing processes, the level of maximum deviator stress under the initial suction pressure of 50kPa was higher than that under the initial suction pressure of 10kPa. On the other hand, the volume changes became smaller under the increase in the initial suction pressure.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1039-1046
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• 2005

After clay particles have been sediment isotropically, the clay deposits have been consolidated under $K_0$-stress system. Therefore, in order to predict the behavior in-situ of normally consolidated clays, the laboratory test should be enforced under $K_0$-stress system and should obtain the characteristics of normally consolidated clays. And relationship of stress-strain on clay is effected on not only method of consolidation but also characteristic of visco-plastic behavior. Saturated clay is effected more this trend. So, rate of strain is considered to understand exact stress-strain relationship. In this study, the series of undrained triaxial compression tests were preformed on remolded specimens which was made by slurry of clay, consolidated under $K_0$-stress systems. And the undrained triaxial compression test were preformed to examine behavior of stress-strain relationship due to rate of shear strain relationship due to rate of shear strain.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.146-153
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• 1990

A new 3-D segmentation-based coding technique is proposed for transmitting the motion video with reasonablly acceptable quality even at a very low bit rate. Only meaningful motion areas are extracted by using two change detection masks and a current frame is directly segmented rather than a difference frame itself so that a good quality of image can be obtained at high compression ratios. Through the experiments, the sequence of Miss America is reconstructed with visually acceptable quality at the very high compression ratio of 360:1.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.329-334
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• 2011

This paper presents improvement of compression rate for SPIHT algorithm based on wavelet compression through redundancy bit removing. Proposed SPIHT algorithm uses a method to select of optimized threshold from feature of wavelet transform coefficients and removes sign bit only if coefficient is LL area. Finally Proposed SPIHT algorithm applies to Huffman coding. Experimental results show that the proposed algorithm achieves more improvement bit rate and more fast progressive transmission with low bit rate.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.1
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• pp.26-31
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• 1997

One of the most common benign tumors of bone is the osteochondroma which is a cartilage-capped bony projection on the surface of a bone. It may occur in any bone that has been performed from cartilage, but the most common locations are the long bone at the metaphyseal region of the most active growth cartilage, that is, the lower end of femur, the upper end of the tibia, and the upper end of the humerus. Other bones often involved are the ilium, scapula, fibula, and phalanges of hands and feet. But, the vertebral column is very rare location for osteochondroma. Only one case of osteochondroma involving the lumbar spine has been previously reported in Korea. We report an unusual case of osteochondroma arising from the left lamina and inferior articular process of the 3rd lumbar spine causing spinal cord compression.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2411-2414
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• 2003

In this paper, we present a digital image authentication using semi-fragile watermarking techniques. The algorithm is robust to innocuous manipulations while detecting malicious manipulations. Specifically, the proposed method is designed for the purpose of the real time authentication of an image frame captured from a digital camera due to its easy H/W implementation, security and visible verification. To achieve the semi-fragile characteristics that survive a certain amount of compression, we employ the invariant property of DCT coefficients' quantization proposed by Lin and Chang [1]. The binary watermark bits are generated by exclusive ORing the binary logo with pseudo random binary sequences. Then watermark bits are embedded into the LSBs of pre-quantized DCT coefficients in the medium frequency range. Verification is carried out easily due to visually recognizable pattern of the logo extracted by exclusive ORing the LSBs of the embedded DCT coefficient with pseudo random number seeded by a secret key. By the experiment results, this method is not only robust to JPEG compression but also it detects powerfully alterations of the original image, such as the tempering of images.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.1
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• pp.42-49
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• 2010

Increasing environmental concerns regarding the use of fossil fuels and global wanning have prompted researcher to investigate alternative fuels. The purpose of this study is to investigate the syngas production by biogas reforming using a compression spark ignition engine. The parametric screening studies were carried out according to the variations of oxygen enrichment rate, biogas $CO_2$ ratio, intake gas temperature, and engine revolution. When the oxygen enrichment rate and input gas temperature increased, hydrogen and carbon monoxide were increased. But the biogas $CO_2$ ratio and engine revolution increased, the syngas were reduced. For the reforming of methane 100% only, generation of hydrogen and carbon monoxide was 58% and 17%, respectively. However when the biogas $CO_2$ ratio was 40%, hydrogen and carbon monoxide concentration were about 20% each.

• Composites Research
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• v.14 no.2
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• pp.43-49
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• 2001

The characteristics of smart skin for wireless LAN system under compression load are investigated. The smart skin structure is composed of 3 layers of face material and 2 layers of core material. Theoretical formula for determining buckling load is derived by Rayleigh-Ritz method and compared with experimental result. The maximum length of specimen that buckling does not occur is determined by assuming that the compression load is sustained by only face material. In the experiment, if buckling occurs obviously then it follows the theoretical result well. In the process of buckling, the load supporting capability and the antenna property such as radiation pattern and reflection coefficient were examined.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.1
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• pp.61-68
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• 2006

The p-version nonlinear finite element model has been developed to analyze the nonlinear behavior of simply supported RC slabs strengthened with carbon fiber reinforced plastic sheets. The shape function is adopted with integral of Legendre polynomials. The compression model of concrete is based on the Kupfer's yield criterion, hardening rule, and crushing condition. The cracking behavior is modeled by a smeared crack model. In this study, the fixed crack approach is adopted as being geometrically fixed in direction once generated. Each steel layer has a uniaxial behavior resisting only the axial force in the bar direction. Identical behavior is assumed fur tension and compression of steel according to the elastic modulus. The carbon fiber reinforced plastic sheets are considered as reinforced layers of equivalent thickness with uniaxial strength and rigidity properties in the present model. It is shown that the proposed model is able to adequately predicte the displacement and ultimate load of nonlinear simply supported RC slabs by a patch with respect to reinforcement ratio, thickness and angles of CFRP sheets.