• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.2
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• pp.68-78
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• 2000

This paper suggests a new map-matching algorithm for matching traveling trace of vehicle, which is measured by GPS receiver, to the road of a digital map This eventually brings the Improvement of positioning accuracy of the vehicle with GPS receiver After representing the travelling vehicle's motion by state equations using Singer's model, the proposed map-matching algorithm places the position of a vehicle right on the road and also improves the positioning accuracy of the vehicle using a Kalman filter In the crossroad, since it is difficult to determine precisely a current travelling road, we take linear regression to the estimated values from Kalman filtering This gives the direction angle of turning vehicle, then we can determine the correct route direction after comparing with each route-direction angle at the intersection.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.395-404
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• 2013

A pattern matching algorithm plays an important role in traffic identification and classification based on predefined patterns for intrusion detection and prevention. As attacks become prevalent and complex, current patterns are written using regular expressions, called regexes, which are expressed into the deterministic finite automata(DFA) due to the guaranteed worst-case performance in pattern matching process. Currently, because of the increased complexity of regex patterns and their large number, memory-efficient DFA from states reduction have become the mainstay of pattern matching process. However, most of the previous works have focused on reducing only the number of states on a single automaton, and thus there still exists a state blowup problem under the large number of patterns. To solve the above problem, we propose a new state compression algorithm that merges states on multiple automata. We show that by merging states with the same input character on multiple automata, the proposed algorithm can lead to a significant reduction of the number of states in the original DFA by as much as 40.0% on average.

• The KIPS Transactions:PartB
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• v.9B no.1
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• pp.29-34
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• 2002

Fingerprint recognition technology was studied by classification and matching. In general, there are five different classifications left loop, right loop, whore, arch, and tented-arch. These classifications are used to determine which class an individual's fingerprint belong to, thereby identifying the individual's fingerprint pattern. The result of this classification, which is sent to the large fingerprint database as an index, helps reduce the matching time and enhance the accuracy of fingerprint matching. The existing fingerprint classification method relies on the number and location of cores and delta points called singular points. The drawback of this method is the lack of accuracy stemming from the classification difficulty involving unclear and/or partially-erased fingerprints. The current paper presents an efficient classification method to rectify the problem associated with identifying Singular points from unclear fingerprints. This method, which is based on Gabor filter's unique characteristics for magnifying directional patterns and frequency range selections, improves fingerprint classification accuracy significantly. In this paper, this method is described and its test result is presented for verification.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.12
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• pp.76-84
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• 1999

This paper presents an integrated method for aircraft position estimation using sequential aerial images. The proposed integrated system for position estimation is composed of two parts: relative position estimation and absolute position estimation. Relative position estimation recursively computes the current position of an aircraft by accumulating relative displacement estimates extracted from two successive aerial images. Simple accumulation of parameter values decreases reliability of the extracted parameter estimates as an aircraft goes on navigating, resulting in large position error. Therefore absolute position estimation is required to compensate for the position error generated in relative position estimation. Absolute position estimation algorithms by image matching or digital elevation model (DEM) matching are presented. In image matching, a robust oriented Hausdorff measure (ROHM) is employed whereas in DEM matching an algorithm using multiple image pairs is used. Computer simulation with four real aerial image sequences shows the effectiveness of the proposed integrated position estimation algorithm.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.9-20
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• 2012

In computer vision, it is very important to obtain reliable corresponding feature points. However, we know it is not easy to find the corresponding feature points exactly considering by scaling, lighting, viewpoints, etc. Lots of SIFT methods applies the invariant to image scale and rotation and change in illumination, which is due to the feature vector extracted from corners or edges of object. However, SIFT could not find feature points, if edges do not exist in the area when we extract feature points along edges. In this paper, we present a new placement method of marker to improve the performance of SIFT feature detection and matching between different view of an object or scene. The shape of the markers used in the proposed method is formed in a semicircle to detect dominant direction vector by SIFT algorithm depending on direction placement of marker. We applied De Bruijn sequence for the markers direction placement to improve the matching performance. The experimental results show that the proposed method is more accurate and effective comparing to the current method.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.99-105
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• 2017

Generally, stereo matching methods are used to estimate depth information based on color and spatial similarity. However, most depth estimation methods suffer from the occlusion region because occlusion regions cause inaccurate depth information. Moreover, they do not consider the temporal dimension when estimating the disparity. In this paper, we propose a temporal stereo matching method, considering occlusion and disregarding inaccurate temporal depth information. First, we apply a global stereo matching algorithm to estimate the depth information, we segment the image to occlusion and non-occlusion regions. After occlusion detection, we fill the occluded region with a reasonable disparity value that are obtained from neighboring pixels of the current pixel. Then, we apply a temporal disparity estimation method using the reliable information. Experimental results show that our method detects more accurate occlusion regions, compared to a conventional method. The proposed method increases the temporal consistency of estimated disparity maps and outperforms per-frame methods in noisy images.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.79-84
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• 2019

This paper compare the performance of CM-MMA (Constellation Matching-MMA) and RMMA (Region-based MMA) blind equalization algorithm for improve the QoS by minimizing the intersymbol interference that is occurred in nonlinear communication channel when transmitting the QAM signal. In the tap coefficient update for adaptive, CM-MMA use the error of nonconstant modulus signal adding the current MMA cost fuction and constellation matching error terms of sinusoidal power function, and the RMMA use the error by transfoms the nonconstant modulus signal of equalizer output constellation to 4-QAM constant modulus signal. They has different equalization performance by these error signal, it were compared in this paper by simulation, and performance index such as output signal constellation of equalizer, residual isi, maximum distortion, SER curves are applied for this. As a result of computer simulation, the RMMA has more better performance in the every performance index, convergence speed, residual value, noise robustness compared to CM-MMA.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.3
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• pp.1051-1077
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• 2021

The secure communication of information is a major concern over the internet. The information must be protected before transmitting over a communication channel to avoid security violations. In this paper, a new hybrid method called compressed encrypted data embedding (CEDE) is proposed. In CEDE, the secret information is first compressed with Lempel Ziv Welch (LZW) compression algorithm. Then, the compressed secret information is encrypted using the Advanced Encryption Standard (AES) symmetric block cipher. In the last step, the encrypted information is embedded into an image of size 512 × 512 pixels by using image steganography. In the steganographic technique, the compressed and encrypted secret data bits are divided into pairs of two bits and pixels of the cover image are also arranged in four pairs. The four pairs of secret data are compared with the respective four pairs of each cover pixel which leads to sixteen possibilities of matching in between secret data pairs and pairs of cover pixels. The least significant bits (LSBs) of current and imminent pixels are modified according to the matching case number. The proposed technique provides double-folded security and the results show that stego image carries a high capacity of secret data with adequate peak signal to noise ratio (PSNR) and lower mean square error (MSE) when compared with existing methods in the literature.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.63-67
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• 2009

Current mismatch in a charge pump causes degradation in spectral purity of the phase locked loops(PLLs), such as reference spurs. The current mismatch can be reduced by increasing the output resistance of the charge pump, as in a cascoded output stage. However as the supply voltage is lowered, it is hard to stack transistors. In this paper, a new method for reducing the current mismatch is proposed. The proposed method is based on a feed-forward compensation for the channel length modulation effect of the output stage. The new method has been demonstrated through simulations on typical $0.18{\mu}m$ CMOS circuits.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.469-471
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• 2008

The charge pump affects the performance of PLL. In designing the charge pump, we need to consider various issues such as current mismatch, charge sharing, feedthrough, charge injection, and leakage current. This paper propose the new charge pump circuit which is improved in terms of the current match over the existing high-speed charge pump. The simple method used for reducing current mismatch is the technique that uses a cascode in order to increase the output resistance of the charge pump. However the method limits the output voltage range of the charge pump. So the method is hard to apply as the supply voltage is lowered. Thus this paper proposes a new charge pump circuit using an op amp instead of the cascode. And the new charge pump circuit has an excellent current matching characteristics over a wide output range.