• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.9
• /
• pp.889-897
• /
• 2002

In this paper, we propose an improved block coding scheme for PAPR reduction in the OFDM communication system. Unlike the conventional block coding scheme which uses one block encoder of subcarrier N, two block encoders of subcarrier N/2 is used for the proposed block coding scheme. This not only improves the coding gain, but enhances the spectral efficiency by twice due to the increment of code rate. PAPR Reduction performance is the same as the conventional block coding. When BER is $10^{-4}$, the proposed block coding scheme has coding gain of 0.5 dB than the conventional scheme.

• Journal of Korea Multimedia Society
• /
• v.3 no.4
• /
• pp.372-379
• /
• 2000

In this paper, we propose a fast variable-size block matching algorithm for motion estimation based on bit-pattern. Motion estimation in the proposed algorithm is performed after the representation of image sequence is transformed 8bit pixel values into 1bit ones depending on the mean value of search block, which brings a short searching time by reducing the computational complexity. Moreover, adaptive searching methods according to the motion information of the block make the procedure of motion estimation efficient by eliminating an unnecessary searching of low motion block and deepening a searching procedure in high motion block. Experimental results show that the proposed algorithm provides better performance-0.5dB PSNR improvement-than full search block matching algorithm with a fixed block size.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1998.06a
• /
• pp.750-755
• /
• 1998

Due to the temporal spatial correlation of the image sequence, the motion vector of a block is highly related to the motion vectors of its adjacent blocks in the same image frame. If we can obtain useful and enough information from the adjacent motion vectors, the total number of search points used to find the motion vector of the block may be reduced significantly. Using that idea, an efficient fuzzy prediction search (FPS) algorithm for block motion estimation is proposed in this paper. Based on the fuzzy inference process, the FPS can determine the motion vectors of image blocks quickly and correctly.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.8 no.4
• /
• pp.248-253
• /
• 2008

In this paper, a novel vehicle detection algorithm is proposed that utilizes the color histogram of the image. The color histogram is used to search the image for regions with shadow, block symmetry, and block non-homogeneity, thereby detecting the vehicle region. First, an integral histogram of the input image is computed to decrease the amount of required computation time for the block color histograms. Then, shadow detection is performed and the block symmetry and block non-homogeneity are checked in a cascade manner to detect the vehicle in the image. Finally, the proposed scheme is applied to both still images taken in a parking lot and an on-road video sequence to demonstrate its effectiveness.

• The Journal of Society for e-Business Studies
• /
• v.19 no.2
• /
• pp.75-93
• /
• 2014

We deal with the design of the effective block logistics operating system in shipyard. The block logistics operation is one of the critical managerial problems in shipbuilding. The block logistics operation in shipyard consists of storage operation for temporary storage in the limited storage area and transfer equipment operation of blocks from the given storage area to next process according to the block production schedule. We propose a design method of block logistics operating system based on the axiomatic design and IDEF0 method. As a result of axiomatic design, system functions are determined regarding implementation sequence. We validated the proposed design by implementation of a block logistics operating system for a large scale shipyard.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.787-788
• /
• 2008

In this paper, we propose a Motion Estimation (ME) based on Frame Difference (FD) for frame interpolation in video sequence with luminance variation. Proposed algorithm uses limited blocks whose motion is predicted by FD for ME. The Block average of current and previous frame for the blocks which has no motion variation is used as interpolated block. In experiments, the proposed algorithm shows better performance than conventional algorithms.

• Proceedings of the IEEK Conference
• /
• 2002.06d
• /
• pp.101-104
• /
• 2002

This paper proposes a unique data embedding algorithm for the video sequence. It describes two processings: shot boundary detection and robust data embedding. First, for the shot boundary detection, instead of using absolute frame differences, block by block based relative frame differences are employed. Frame adaptive thresholding values are also employed for the better detection. Second, for the robust data embedding, we generate message template and then convolve and correlate it with carrier signal. And then we embed data on the time domain video sequence. By using these two methods, watermarks into randomly selected frames of shots. Watermarks are detected well even if several certain shots are damaged because we embed watermark into each shot equally.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.12
• /
• pp.1797-1805
• /
• 1993

An algorithm for the threshold decision from the maximum mismatching correlation value in a direct-sequence spread-spectrum system is presented. This algorithm is named the TDMMC(Threshold Decision from the Maximum Mismatching Correlation value). The purpose of the algorithm is to set the decision threshold in the system which will provide large probability of signal detection. Using this algorithm, the proper setting of the threshold for various SNRs is possible. An additional block called the Threshold Block is used to improve the system performance. The result from the computer simmulation has shown that appling the TDMMC to the noncoherent DS/SS-CSK system can achieve performance improvement.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.9 no.2
• /
• pp.117-122
• /
• 2009

In this paper, the performance of double binary turbo code is analyzed and simulated in ultra wide-band (UWB) systems employing multiple-antenna scheme. We consider both pulse position modulation-time hopping (PPM-TH) and pulse amplitude modulation-direct sequence (PAM-DS) UWB systems. The space time block code (STBC) scheme is adopted as a transmit diversity method. Also, receive diversity scheme is applied. And double binary turbo code is applied to the UWB system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.83-86
• /
• 2007

In the blind Maximum-likelihood (ML) detection for Orthogonal Space-Time Block Codes (OSTBC), the problem of ambiguity in determining the symbols has been a great concern. A solution to this problem is to apply semi-blind ML detection, i.e., the blind ML decoding with pilot symbols or training sequence. In order to increase the performance, the number of pilot symbols or length of training sequence should be increased. Unfortunately, this leads to a significant decrease in system spectral efficiency. This work presents an approach to resolve the aforementioned issue by introducing a new method for constructing transmitted information symbol. Thus, by transmitting information symbols drawn from different modulation constellation, the ambiguity can be easily eliminated in blind detection. Also, computer simulations are implemented to verify the performance of the proposed approach.