• The KIPS Transactions:PartA
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• v.8A no.1
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• pp.36-41
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• 2001

In this paper, we first design an parallel quadratic sieve algorithm for factoring method. We then present parallel factoring algorithm for factoring a large odd integer by repeatedly using the parallel quadratic sieve algorithm based on the divide-and-conquer strategy on SIMD machines with DMM. We show that this algorithm is optimal in view of the product of time and processor numbers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1624-1632
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• 1996

Wavelet transform is widely used for high compression ratio image compression. It requeires a large memory when it is implemented by a hardware. Therefore, it is efficient to divide the entire image into blocks. Because the wavelet transform for divided blocks causes losses, pixels of the adjacent blocks are used. In the case of color image compression, the image is decomposed into brightness and color components, and then color components are downsampled. When the wavelet transform is performed by using pixels of adjacentblocks, the number of necessary pixels are doubled due to downsampling of color components. In this paper, we propose an efficient block wavelet transform using variablefilter length for brightness and color components. By using the proposed method, the number of pixels of adjacent blocks is optimized. We show the degradation of image quality due to the reduction of filter length for color components is negligible through simulations.

• Journal of the Korea Society of Computer and Information
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• v.23 no.4
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• pp.33-39
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• 2018

In this paper, we propose a describes how to detect a false iris image by inserting watermark into a iris image. The existing method, which inserts the watermark into the entire iris image to detect a fake iris, has a problem that can evade it by segmenting iris region of an iris image. The purpose of overcoming the problem, this paper proposes a new fake iris detection technique based on digital watermark. It first searches a central point of an iris image, divide the image into blocks with respect to the point. executes Discrete Cosine Transform, inserts watermark into the blocks, and then verifies an iris image using NC(Normalized Correlation). In the experiments, we confirm the robustness for attacks - crop and JPEG.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.498-502
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• 2002

Section insulators are indispensible devices for the electric railways, which divide electrical connections between the trolley lines without losing mechanical connections, and this means that they should have both good electrical insulation performance and mechanical performance for pantograph interaction. This paper reviews some technical aspects of the several type section insulators and makes analysis of difficulties during operation. The closed type section insulators are proposed for newly electrified railways, because they have good mechanical and electrical performances for high speed trains up to 200[km/H]. Technical specifications of closed-type section insulators based on survey of the advanced technologies are provided, and also the neutral section configuration method which might be the best solution for newly electrified railways in Korea of 200km/H speed.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.135-138
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• 2001

This paper presents micro step driving method using VHDL(Very high speed integrated circuit Hardware Description Language) which can configure CPLD(Complex Programmable Logic Device). Using VHDL which can do abstractive programming is similar to high level language. The whole block divided into five parts with freq. divide part, saw-tooth wave generation part, sine-cosine wave generation part, comparative part, out part. In the result of this study, peripheral circuits are to be simple and using LPM(Library of Parameterized Modules) is more easily to configure circuit. It is easy to verify and implement by using VHDL. To subdivide one natural step, we confirm that using micro step driver is expected that the rotor motion is stepless very smooth.

• Speech Sciences
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• v.14 no.2
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• pp.127-135
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• 2007

Feature vectors of speech are generally extracted from whole frequency domain. The inherent character of a speaker is located in the low band or high band frequency. However, if the speech is corrupted by narrowband noise with concentrated energy, speaker verification performance is reduced as the individual characteristic is removed. In this paper, we propose a PCA Covariance Model based on the multiband to extract the robust feature vectors against the narrowband noise. First, we divide the overall frequency band into several subbands. Second, the correlation of feature vectors extracted independently from each subband is removed by PCA. The distance obtained from each subband has different distribution. To normalize against the different distribution, we moved the value into the normalized distribution through the mapping function. Finally, the represented value applying the weighting function is used for speaker verification. In the experiments, the proposed method shows better performance of the speaker verification and reduces the computation.

• East Asian mathematical journal
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• v.33 no.4
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• pp.467-482
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• 2017

This paper studies the relationship between the college entrance examination scores and college mathematics achievements of the freshman, who are the students of college of technology and management in Yanbian University, by employing statistical analysis. First of all, we start from the correlation analysis of the majors and regions of students. Secondly, with gender and region as the classification, we divide the sample into two parts and test the mean significance, and we find that not only different gender but also different region have significant differences to college mathematics achievements. Thirdly, we use the college entrance examination scores as independent variable, and college mathematics achievement as the dependent variable to establish regression model. The model provides a realistic basis for the education department of our school, and provides reference value for the other major research.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.145-156
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• 2003

This paper for real time object tracking in this treatise detect histogram analysis that is accumulation value of binary conversion density and edge information and body that move by real time use of difference Image techniques and proposed method to object tracking. Firstly, we extract edge that can reduce quantity of data keeping information about form of input image in object detection. Object is extracted by performing difference image and binarization in edge image. Area of detected object is determined by threshold value that divide sum of horizontal accumulation value about binary conversion density by value that add horizontalityㆍverticality maximum accumulation value. Object is tracked by comparing similarity with object that is detected in previous frame and present frame. As experiment result, proposed algorithm could improve the object detection speed, and could track object by real time and could track local movement.

• Journal of the Korean housing association
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• v.9 no.1
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• pp.21-32
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• 1998

This is study on the changes of the Apartment House Managerial Problems to grope for the way of more practical management about increasing the apartment house in Korea. The documentary research method was used for this study and the Han-Kook newspapers (1954-1991) was used as an analysis data. On the basis of it, we examined the changes, such as the number of whole articles by time series and the column of head title. We also classified it into several subjects and analyzed it. Finally, we attempted to divide an chronological section on the Changes of the Apartment House Managerial Problems. On the basis of this study, we expect that various documents, related laws and regulations will be analyzed in no distant future. These is going to make the Apartment House Managerial Problems gave more systemic and efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.425-430
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• 2017

This paper presents a novel method for identification of FSK modulated radar signal. Three features which measure the number of frequency tones, the regularity of the frequency shifting, and the diversity of power spectrum of detected radar signal, are introduced. A Two-step combined maximum likelihood classifier was used to identify the details of the detected FSK signal; the modulation order and the use of Costas code. We attempted to divide FSK signal into binary FSK, ternary FSK, 8-ary FSK, and FSK with Costas code of length 7. The simulation results indicated that the proposed methods achieves an averaged identification accuracy was 99.93% at a signal-to-noise of 0 dB.