• Journal of Communications and Networks
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• v.11 no.6
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• pp.607-614
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• 2009

Recently, Lu et al. proposed an efficient conditional privacy preservation protocol, named ECPP, based on group signature scheme for generating anonymous certificates from roadside units (RSUs). However, ECPP does not provide unlinkability and traceability when multiple RSUs are compromised. In this paper, we make up for the limitations and propose a robust and efficient anonymous authentication protocol without loss of efficiency as compared with ECPP. Furthermore, in the proposed protocol, RSUs can issue multiple anonymous certificates to an OBU to alleviate system overheads for mutual authentication between OBUs and RSUs. In order to achieve these goals, we consider a universal re-encryption scheme and identity-based key establishment scheme as our building blocks. Several simulations are conducted to verify the efficiency and effectiveness of the proposed protocol by comparing with those of the existing ECPP.

• Genomics & Informatics
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• v.6 no.3
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• pp.130-135
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• 2008

The haplotypes of a 200 kb region in the human chromosome X terminal band (q28) were analyzed using the International HapMap Project Phasell data, which had been collected for three analysis panels (YRI, CEU, and CHB＋JPT). When multiple linkage disequilibrium blocks were encountered for a panel, the neighboring haplotypes that had crossover rate of 5% or more in the panel were combined to generate 'haploid' configurations. This resulted in 8, 7, and 5 'haploid' configurations for the panels of YRI, CEU, and CHB＋JPT, respectively. The multiple sequence alignment of these 'haploids' was used for the calculation of allele-sharing distances and the subsequent principal coordinate analysis. Two 'haploids' in CEU and CHB＋JPT were hypothesized as 'parental' in light of the observations that the successive recombinants of these haploids can model two other haploids in CEU and CHB＋JPT, and that their configurations were consistent with those in YRI. This study demonstrates the utility of haplotype phylogeny in understanding population evolution.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4C
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• pp.253-261
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• 2005

In this paper, we propose an efficient block-based disparity estimation algorithm fur multiple view image coding in EE2 and EE3 in 3DAV. The proposed method emphasizes on visual quality improvement to satisfy the requirements for multiple view generation. Therefore, we perform an adaptive disparity estimation that constructs variable blocks by considering given image features. Examining neighboring features around desired block search range is set up to decrease complexity and additional information than only using quad-tree coding through applying binary-tree and quad-tree coding by taking into account stereo image feature having big disparity. The experimental results show that the proposed method improves PSNR about 1 to 2dB compared to existing other methods and decreases computational complexity up to maximum 68 percentages than FBMA.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1075-1082
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• 2017

This paper describes a design of hash processor which can execute new hash algorithm, SHA-3 and extendable-output function (XOF), SHAKE-256. The processor that consists of padder block, round-core block and output block maximizes its performance by using the block-level pipelining scheme. The padder block formats the variable-length input data into multiple blocks and then round block generates SHA-3 message digest or SHAKE256 result for multiple blocks using on-the-fly round constant generator. The output block finally transfers the result to host processor. The hash processor that is implemented with Xilinx Virtex-5 FPGA can operate up to 220-MHz clock frequency. The estimated maximum throughput is 5.28 Gbps(giga bits per second) for SHA3-512. Because the processor supports both SHA-3 hash algorithm and SHAKE256 algorithm, it can be applicable to cryptographic areas such as data integrity, key generation and random number generation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.3
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• pp.40-49
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• 1989

A variable-state block interference channel model is presented which matches asynchronous multiple-access slow frequency-hopped spread-spectrum systems which suffer from bursts of interference of variable duration. For variable-state block interference channels test pattern techniques combined with interleaving are presented from which the decoder obtain side information about channel states. By examining test patterns the decoder estimates which parts of data blocks are affected by interference and regards the parts of blocks affected by interference as erasures. Since the presence of test patterns reduces the number of bits for data transmission, test patterns are not useful for variable-state block interference channels for small hit probability, It is shown that test patterns increase the capacities of variable-state block interference channels for large hit probability. It is also shown that test patterns provide a almost full side information about channel states for certain values of parameters.

• Journal of Power Electronics
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• v.17 no.3
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• pp.821-834
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• 2017

This paper reports on a single-inductor multiple-output step-up converter with digital control. A systematic analog-to-digital-controller design is explained. The number of digital blocks in the feedback path of the proposed converter has been decreased. The simpler digital pulse-width modulation (DPWM) architecture is then utilized to reduce the power consumption. This architecture has several advantages because counters and a complex digital design are not required. An initially designed unit-delay cell is adopted recursively for the construction of coarse, intermediate, and fine delay blocks. A digital limiter is then designed to allow only useful code for the DPWM. The input voltage is 1.8 V, whereas output voltages are 2 V and 2.2 V. A co-simulation was also conducted utilizing PowerSim and Matlab/Simulink, whereby the 55 nm process was employed in the experimental results to evaluate the performance of the architecture.

• The KIPS Transactions:PartB
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• v.11B no.6
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• pp.661-666
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• 2004

In the wireless communication systems, transmission errors degrade the reconstructed image quality severely. Error concealment in video communication is becoming increasingly important because transmission errors can cause single or multiple loss of macroblocks in video delivery over unreliable channels such as wireless networks and internet. Among various techniques which can reduce the degradation of video quality, the error concealment techniques yield good performance without overheads and the modification of the encoder. In this paper, lost image blocks can be concealed with the OBMC(Overlapped Block Motion Compensation) after new motion vectors of the lost image blocks are allocated by median values using the adaptive selection with motion vectors of adjacent blocks. We know our algorithm is more effective in case of continuous GOB loss. The results show a significant improvement over the zero motion error concealment and other temporal concealment methods such as Motion Vector Rational Interpolation or Median＋OBMC by 3dB gain in PSNR.

• The Korean Journal of Pain
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• v.31 no.1
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• pp.27-38
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• 2018

Background: Related to escalating health care costs and the questionable effectiveness of multiple interventions including lumbar facet joint interventions, cost effectiveness or cost utility analysis has become the cornerstone of evidence-based medicine influencing coverage decisions. Methods: Cost utility of therapeutic lumbar facet joint nerve blocks in managing chronic low back pain was performed utilizing data from a randomized, double-blind, controlled trial with a 2-year follow-up, with direct payment data from 2016. Based on the data from surgical interventions, utilizing the lowest proportion of direct procedural costs of 60%, total cost utility per quality adjusted life year (QALY) was determined by multiplying the derived direct cost at 1.67. Results: Patients in this trial on average received $5.6{\pm}2.6$ procedures over a period of 2 years, with average relief over a period of 2 years of $82.8{\pm}29.6$ weeks with $19{\pm}18.77$ weeks of improvement per procedure. Procedural cost for one-year improvement in quality of life showed USD $2,654.08. Estimated total costs, including indirect costs and drugs with multiplication of direct costs at 1.67, showed a cost of USD $4,432 per QALY. Conclusions: The analysis of therapeutic lumbar facet joint nerve blocks in the treatment of chronic low back pain shows clinical effectiveness and cost utility at USD $2,654.08 for the direct costs of the procedures, and USD $4,432 for the estimated overall cost per one year of QALY, in chronic persistent low back pain non-responsive to conservative management.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.725-733
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• 2000

In this paper, we propose a modified boundary block merging technique for the texture coding of MPEG-4. We propose an ORP(Optimized Region Partitioning) method that partition the VOP-based reference position to minimize the number of coding blocks. The merging possibility is improved by adding +90。and -90。 Rotation merging. We propose a MRM(Multiple Rotation Merging) method which applies the rotation merging in the order of 180。, +90。and -90。. If a pair of boundary blocks has low correlation, existing BBM's padding technique is not efficient. Our padding after merging method gives better result even if it has low correlation. The proposed method showed 5 ~8(%) coding bit reduction at the same PSNR values compared to BBM method.

• Smart Media Journal
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• v.4 no.2
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• pp.26-33
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• 2015

In this paper, we propose an efficient automatic pedestrian removal system from a frame in a video sequence. It firstly finds pedestrians from the frame using a Histogram of Oriented Gradient(HOG) / Linear-Support Vector Machine(L-SVM) classifier, searches for proper background patches, and then the patches are used to replace the deleted pedestrians. Background patches are retrieved from the reference video sequence and a modified feather blender algorithm is applied to make boundaries of replaced blocks look naturally. The proposed system, is designed to automatically detect object and generate natural-looking patches, while most existing systems provide search operation in manual. In the experiment, the average PSNR of the replaced blocks is 19.246