• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.5
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• pp.68-74
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• 1998

Block-based interframe interpolation algorithms cause severe block effect because the algorithm interpolates the skipped frame by using block based motion vector. Therefore, in this paper, we propose an algorithm that reduces the block effect in the interpolated frames. First, we propose an algorithm that obtains backward motion vector by using forward motion vector received from the transmitter. In order to predict well covered and uncovered region, backward motion vector is needed as well as forward motion vector. Second, we propose the algorithm which segments the motion boundary blocks into regions and obtains the motion vector of each region from candidates that consist of the motion vectors of neighbor blocks. This algorithm makes it possible that the moving object and the background, in spite of being in the same block, have different motion vectors from each other so that the block effect can be reduced. According to the results of simulation, the proposed algorithm is superior to conventional algorithm in subjective quality a swell as in objective quality.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.235-240
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• 2002

The blocks using flyash were prepared in this study. The characteristic of sound absorption of flyash block was investigated. It was revealed that the chemical additives and flyash played an important role to determine the characteristic of sound absorption. Chemical additive affects the capability of sound absorption while flyash affects the characteristic of sound absorption, i.e. high value of the sound absorption coefficient at the specific frequencies(1KHz and 2KHz). The flyash block showed higher sound absorption coefficient than that of the commercial concrete block having carpet on the surface. It was also shown that the sound absorption coefficient increases with increase of the content of flyash in the block. However, it was found that the 70wt% of flyash in the flyash block was the optimum content to obtain the highest sound absorption coefficient.

• Journal of Communications and Networks
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• v.8 no.3
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• pp.275-285
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• 2006

Suitable for multi-input multi-output (MIMO) communications, the joint beamforming space-time block coding (JBSTBC) scheme is proposed for high-speed downlink transmission. The major functionality of the scheme entails space-time block encoder and joint transmit and receive eigen-beamformer (EBF) incorporating with block-ordered layered decoder (BOLD), and its operating principle is described in this paper. Within these functionalities, the joint EBFs will be utilized for decorrelating fading channels to cause an enhancement in the spatial diversity gain. Furthermore, to fortify the capability of layered successive interference cancellation (LSIC) in block-ordered layered decoding process, this paper will develop a simple ad-hoc transmit power discrimination scheme (TPDS) based on a particular power discrimination function (PDF). To confirm the superior behavior of the proposed JBSTBC scheme employing ad-hoc TPDS, computer simulations will be conducted under various channel conditions with the provision of detailed mathematical derivations for clarifying its functionality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.675-684
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• 1997

The bit rate control algorithm which is capable of handing scene change is proposed. In MPEG-2 TM5, block variance is used to measure block activity. But block variance is not consistent with human visual system and does not differenciate the distribution of pixel values within the block. In target bit allocation process of TM5, global complexity, obtained by results of previous coded pictures, is used. Since I pictures are spaced relatively far apart, their complexity estimate is not very accurate. In the proposed algorithm local variance is used to measure block activity and detect scene change. Local variance, using deviation from the mean of neighboring pixels, well represents the distribution of pixel values within the block. If scene change is detected, the local variance information is used for target bit allocation process. Allocating target bits for I picture, the average local variance difference between previous and current I picture is considered. The experimental results show that the proposed algorithm can detect scene change very precisely and gives better picture quality and higher PSNR values than MPEG-2 TM5.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.8
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• pp.390-396
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• 2003

This paper is focused on an optimal block sectioning technique which are widely used in conventional railway system. We studied braking distance with pure train braking performance to generalize train braking. We tried to apply the braking distance to wayside signaling system to decide optimal block sectioning to reduce headway. The braking distances are obtained for 2 aspects, 3 aspects, 4 aspects and n aspects such that step speed control, are longer than the pure braking distance. We found an optimal solution with the generalized n aspects, and a minimum block distance for ATO mode.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.7
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• pp.1089-1096
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• 2001

This paper presents the fatigue behavior of composite materials with impact-induced damage under 2 level block loading. For this purpose, the 2 level block loading fatigue tests were performed on the impacted composite laminate. The fatigue life of the laminate under the block loading is greatly influenced by the impact damage; the effect of impact damage can be characterized by the present impact damage parameter. Based on this parameter, the model is developed to predict the fatigue life under block loading and the results by this model agree well with experimental results regardless of applied impact energy. Also, stochastic model is established to describe the variation of cumulative damage behavior and fatigue life due to the material nonhomogeneity.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.2
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• pp.11-17
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• 2018

IDS/IPS and networked computer systems are playing an increasingly important role in our society. They have been the targets of a malicious attacks that actually turn into intrusions. That is why computer security has become an important concern for network administrators. Recently, various Detection/Prevention System schemes have been proposed based on various technologies. However, the techniques, which have been applied in many systems is useful for existing intrusion patterns on standard-only systems. Therefore, probe detection of private clouds using BlockChain has become a major security protection technology to detection potential attacks. In addition, BlockChain and Probe detection need to take into account the relationship between the various factors. We should develop a new probe detection technology that uses BlockChain to fine new pattern detection probes in cloud service security in the end. In this paper, we propose a probe detection using Fuzzy Cognitive Map(FCM) and Self Adaptive Module(SAM) based on service security using BlockChain technology.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.3
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• pp.16-22
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• 2006

The friction and wear of tire determined by frictional behavior of tire tread that translate driving force, cornering force and braking force between automobile and road as a result of frictional behavior of each tread block. The tire tread block is representative case of rubber block doing frictional behavior. In this paper, frictional behavior of rubber block under compressive force and shear force was analytically obtained by using slip starting position parameter instead of friction coefficient which is uncertain to express exact value between rubber and other surfaces yet. And local coefficients of friction were calculated as a function of compressive force, shear force, shear modulus of rubber, shape factor and slip starting position.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.915-927
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• 1997

In this paper, we propose an error concealment technique using directional interpolation in block-based image compression. In the proposed method the edge direction is determined by finding the maximum correlation coefficients of boundary pixels of blocks neighboring the errored block in spatial domain. Then the errored block is interpolated linearly or bilinearly along the determined edge direction. The proposed method can conceal the block error, the macro block error, and the slice error adaptively. Also, the parameters for the directional interpolation are represented by closed forms. When applied to compressed images, the proposed method shows superior subjective and objective quality to conventional error concealment methods.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2108-2110
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• 2001

Used analog control systems have been converted into digital control systems due to performance degradation and difficulty of maintenance. There are few domestic DCS (Distribued Control System)s that have been applied to power plant. To apply a domestic DCS to power plant, the reliability, redundacny, and fault tolerance of DCS is important. Besides those items, the control action of control function block is also important. In this paper, we describe the requirements that PID control function block has to have, and implement a PID control function block that satisfies those requirements. Finally, real control result using an implemented PID function block in thermal power plant shows the validity of an implemented PID control function block.