• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.3
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• pp.477-489
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• 2014

Based on some flaws occurred for implementing a public key cryptosystem in the embedded security device, many side-channel attacks to extract the secret private key have been tried. In spite of the fact that the cryptographic exponentiation is basically composed of a sequence of multiplications and squarings, a new Square Always exponentiation algorithm was recently presented as a countermeasure against side-channel attacks based on trading multiplications for squarings. In this paper, we propose Known Power Collision Analysis and modified Doubling attacks to break the Right-to-Left Square Always exponentiation algorithm which is known resistant to the existing side-channel attacks. And we also present a Collision-based Combined Attack which is a combinational method of fault attack and power collision analysis. Furthermore, we verify that the Square Always algorithm is vulnerable to the proposed side-channel attacks using computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11B
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• pp.1020-1029
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• 2008

This paper proposes an high speed pattern matching algorithm and its implementation. The pattern matcher is used to check patterns from realtime input packet. The proposed algorithm can find exact string, range of string values, and combination of string values from input packet at high speed. Given string and rule set are modelled as a state transition graph which can find overlapped strings simultaneously, and the state transition graph is partitioned according to input implicants to reduce implementation complexity. The pattern matcher scheme uses the transformed state transition graph and input packet as an input. The pattern matcher was modelled and implemented in VHDL language. Experimental results show the proprieties of the proposed approach.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.3
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• pp.1-11
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• 2013

This study developed the algorithm of location-based service for supplying the efficient tourism service to traveller using mobile device and applied it to the Jeonju HANOK village. First, the location service was advanced using algorithm coupling with GPS error range and travel speed in single line, and with GPS location and nearest neighbor method to line in multiple one. Also this study developed a program using DuraMap-Xr spatial engine for establishing topology to Node and Link in line automatically. And the foundation was prepared for improving travel convenience by programming location-based service technology to single and multiple lines based on Blackpoint-Xr mobile application engine.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.5
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• pp.380-388
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• 2002

This paper describes the optimum design for low-pressure steam turbine rotor of 1,000 MW nuclear power plant by using a combined genetic algorithm, which uses both a genetic algorithm and a local concentrate search algorithm (e.g. simplex method). This algorithm is not only faster than the standard genetic algorithm but also supplies a more accurate solution. In addition, this algorithm can find the global and local optimum solutions. The objective is to minimize the resonance response (Q factor) and total weight of the shaft, and to separate the critical speeds as far from the operating speed as possible. These factors play very important roles in designing a rotor-bearing system under the dynamic behavior constraint. In the present work, the shaft diameter, the bearing length, and clearance are used as the design variables. The results show that the proposed algorithm can improve the Q factor and reduce the weight of the shaft and the 1st critical speed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.887-890
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• 2009

To transmit information over a channel in the presence of noise, there needs some technique to code the information. One of the coding techniques used for error detection and correction close to the Shannon limit is Low Density Parity Code. LDPC and decoding characteristic features by sum-product algorithm are matched for the performance to Turbo Code, RA(Repeat Accumulate) code, in case of very long code length of LDPC surpass their performance. This paper explains LDPC coding scheme of image data and decoding scheme, implements LDPC decoder in FPGA.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.232-237
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• 2013

A newly developed fall detection algorithm using the HMM (Hidden Markov Model) extracted from the video is introduced. To distinguish between the fall from personal difference fall pattern or the normal activities of daily living (ADL), HMM machine learning algorithm is used. For getting fall feature vector of video, the motion vector from the optical flow is applied to the PCA (Principal Component Analysis). The combination of the angle, ratio of long-short axis, velocity from results of PCA make the new fall feature parameters. These parameters were applied to the HMM and the results were compared and analyzed. Among the newly proposed various kinds of fall parameters, the angle of movement showed the best results. The results show that this parameter can distinguish various types of fall from ADLs with 91.5% sensitivity and 88.01% specificity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1409-1418
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• 1998

The recent audio CODEC(Coding/Decoding) algorithms are complex of several coding techniques, and can be divided into DSP tasks, controller tasks and mixed tasks. The traditional DSP processor has been designed for fast processing of DSP tasks only, but not for controller and mixed tasks. This paper presents a new architecture that achieves high throughput on both controller and mixed tasks of such algorithms while maintaining high performance for DSP tasks. The proposed processor, YSP-3, operates four algorithms while maintaining high performance for DSP tasks. The proposed processor, YSP-3, operates functional units (Multiplier, two ALUs, Load/Store Unit) in parallel via 4-issue super-scalar instruction structure. The performance evaluation of YSP-3 has been done through the implementation of the several DSP algorithms and the part of the AC-3 decoding algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.250-258
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• 2005

An initial carrier frequency offset estimation algorithm is proposed for a multi-user frequency bowing orthogonal frequency division modulation-frequency division multiple access (FH-OFDMA) system with a single preamble symbol. To mitigate the effect of the frequency offset, every mobile station needs to accurately and rapidly acquire synchronization. The proposed algorithm uses only one preamble symbol in which two kinds of subcarriers are designed for coarse and fine frequency offset estimation. The non-data aided estimation using the energy spectrum is exploited for fine offset estimation, and maximum likelihood estimation using correlation for coarse offset estimation. By combining the two estimation results, an accurate frequency offset can be estimated with a single symbol. Through simulations, the performance of the proposed algorithm is evaluated by comparing estimation error variance with a conventional method.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.333-338
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• 2000

In this paper, an automated segmentation algorithm is proposed for MR brain images using T1-weighted, T2-weighted, and PD images complementarily. The proposed segmentation algorithm is composed of 3 step. In the first step, cerebrum images are extracted by putting a cerebrum mask upon the three input images. In the second step, outstanding clusters that represent inner tissues of the cerebrum are chosen among 3-dimensional(3D) clusters. 3D clusters are determined by intersecting densely distributed parts of 2D histogram in the 3D space formed with three optimal scale images. Optimal scale image is made up of applying scale space filtering to each 2D histogram and searching graph structure. Optimal scale image best describes the shape of densely distributed parts of pixels in 2D histogram and searching graph structure. Optimal scale image best describes the shape of densely distributed parts of pixels in 2D histogram. In the final step, cerebrum images are segmented using FCM algorithm with its initial centroid value as the outstanding clusters centroid value. The proposed cluster's centroid accurately. And also can get better segmentation results from the proposed segmentation algorithm with multi spectral analysis than the method of single spectral analysis.

• The Journal of the Acoustical Society of Korea
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• v.18 no.1
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• pp.45-52
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• 1999

In this thesis, a packer is proposed and designed for removing the bottle-neck effect and easy signal processing using a new algorithm with the operation frequency of 54MHz. To verify the performance of the proposed packer, DCT coefficient encoding block with ROM table using a combinational logic is designed and its output data are used the input data of the packer. Circuits in this thesis are designed by using VHDL code and its modeling and simulation are performed by SYNOPSYS tool using $0.65{\mu}m$ rule.