• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1734-1740
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• 2015

This paper introduces a generalized notion, referred to as joint locality, of the usual locality in distributed storage systems and proposes a code construction of binary locally repairable codes with joint locality ($r_1$=2, $r_2$=3 or 4). Joint locality is a set of numbers of nodes for repairing various failure patterns of nodes. The proposed scheme simplifies the code design problem utilizing complete multipartite graphs. Moreover, our construction can generate binary locally repairable codes achieving (2,t)-availability for any positive integer t. It means that each node can be repaired by t disjoint repair sets of cardinality 2. This property is useful for distributed storage systems since it permits parallel access to hot data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1807-1823
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• 2016

Local Binary Pattern (LBP) and its variants have powerful discriminative capabilities but most of them just consider each LBP code independently. In this paper, we propose sub oriented histograms of LBP for smoke detection and image classification. We first extract LBP codes from an image, compute the gradient of LBP codes, and then calculate sub oriented histograms to capture spatial relations of LBP codes. Since an LBP code is just a label without any numerical meaning, we use Hamming distance to estimate the gradient of LBP codes instead of Euclidean distance. We propose to use two coordinates systems to compute two orientations, which are quantized into discrete bins. For each pair of the two discrete orientations, we generate a sub LBP code map from the original LBP code map, and compute sub oriented histograms for all sub LBP code maps. Finally, all the sub oriented histograms are concatenated together to form a robust feature vector, which is input into SVM for training and classifying. Experiments show that our approach not only has better performance than existing methods in smoke detection, but also has good performance in texture classification.

• Journal of KIISE:Software and Applications
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• v.32 no.12
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• pp.1260-1270
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• 2005

Support Vector Machines (SVM) is well known for a representative learner as one of the kernel methods. SVM which is based on the statistical learning theory shows good generalization performance and has been applied to various pattern recognition problems. However, SVM is basically to deal with a two-class classification problem, so we cannot solve directly a multi-class problem with a binary SVM. One-Per-Class (OPC) and All-Pairs have been applied to solve the face recognition problem, which is one of the multi-class problems, with SVM. The two methods above are ones of the output coding methods, a general approach for solving multi-class problem with multiple binary classifiers, which decomposes a complex multi-class problem into a set of binary problems and then reconstructs the outputs of binary classifiers for each binary problem. In this paper, we introduce the output coding methods as an approach for extending binary SVM to multi-class SVM and propose new output coding schemes based on the Error-Correcting Output Codes (ECOC) which is a dominant theoretical foundation of the output coding methods. From the experiment on the face recognition, we give empirical results on the properties of output coding methods including our proposed ones.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1996.11a
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• pp.286-294
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• 1996

In a remarkable paper 〔3〕, Hammons et al. showed that, when properly defined, the binary nonlinear Preparata code can be considered as the Gray map of a linear code eve. Z$_4$, the so-called Preparata code eve. Z$_4$. Recently, Yang and Helleseth 〔12〕 considered the generalized Hamming weights d$\_$r/(m) for Preparata codes of length 2$\^$m/ over Z$_4$ and exactly determined d$\_$r/, for r = 0.5,1.0,1.5,2,2.5 and 3.0. In particular, they completely determined d$\_$r/(m) for any r in the case of m $\leq$ 6. In this paper we show that the Preparata code of length 16 over Z$_4$ does not satisfy the chain condition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1128-1135
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• 1993

In this paper, new binary cyclic codes (hereafter, refered to as GMW code) which are generated by using GMW sequence, g(t) = tr((trk(a))r), and its cyclic shifts are introduced. Code length of GMW codes is 2a-1, where k is composite integer, e·J. Dimension of the GMW codes is k(k/j)w-1, where w is a Hamming weight of r. Several properties of GMW codes such as designed distance, minimum distance, and weights of code words are obtained in terms of parameters of GMW sequences. And expansion of GMW sequences in terms of m-sequence and its decimation sequences are introduced and characteristic polynomials of GMW sequences are also derived.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1647-1650
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• 2002

In this paper, a class of multi-level spreading codes, i.e., ternary ZCD(zero-correlation duration) spreading codes are introduced. Novel ternary ZCD code sets are generated by carrying out a chip-shift operation of the ternary preferred pairs (TPP) with a ZCD of(0.75N+1)chips. Ternary ZCD codes have superior family size than the binary ZCD codes and they are effective for approximately synchronized (AS) CDMA

• Bulletin of the Korean Mathematical Society
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• v.60 no.2
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• pp.443-460
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• 2023

A binary linear code is said to be a ℤ₂-double cyclic code if its coordinates can be partitioned into two subsets such that any simultaneous cyclic shift of the coordinates of the subsets leaves the code invariant. These codes were introduced in [6]. A ℤ₂-double cyclic code is called reversible if reversing the order of the coordinates of the two subsets leaves the code invariant. In this note, we give necessary and sufficient conditions for a ℤ₂-double cyclic code to be reversible. We also give a relation between reversible ℤ₂-double cyclic code and LCD ℤ₂-double cyclic code for the separable case and we present a few examples to show that such a relation doesn't hold in the non-separable case. Furthermore, we list examples of reversible ℤ₂-double cyclic codes of length ≤ 10.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.9-17
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• 2004

We present a performance improvement of Binary CDMA by flattening the correlation values. A Binary CDMA system, in which multi-leveled transmission signal of multi-code CDMA is clipped into a binary value, is cost-efficient since the strict linearity of the power amplifier is relieved. However, a loss of orthogonality among user channels due to the clipping causes the correlation values at the receiver to have a random distribution. If the correlation value for even a single channel goes too low, the average BER drops considerably. We developed a method of correlation flattening, where the binary chip pattern at the transmitter is adjusted so that the correlation values have averaged magnitude. Experimental results on several spreading codes show that the correlation flattening method increases the number of available channels at reduced BER.

• Journal of the military operations research society of Korea
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• v.15 no.2
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• pp.94-104
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• 1989

The concept of Algebraic-Coded Cryptosystem has been proposed recently but its application has not been developed yet. The primary object of this paper is to implement the Private-Key Algebraic-Coded Cryptosystem by using the primitive binary BCH codes. In the analysis of the cryptosystein, we find out the fact that there may exist other key pairs $S_i\;and\;P_i$ satisfying $G^*=S_{i},G_{s},P_{i}$ where $SG_{s}P$ is the original cryptosystem made by use of the systematic code generation matrix $G_{s}$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.4
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• pp.374-387
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• 1989

The decoding method of Binary BCH Codes using symmetric matrix is proposed in this paper. With this method, the error-locator-polynomial is composed by symmetric matrix which consists of the powers of the unknown X plus the synfromes as its elements. The symmetric matirx can also be represented in terms of the unknown X. But the each coefficients of the error-locator polynomial represents the matirx with the syndromes as its entries. By utilizing this proposed algorithm, the device for decoding circuit of the (63, 45) BCH Code for t=3 has been implemented for demonstration.