• Journal of Korea Multimedia Society
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• v.7 no.8
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• pp.1035-1045
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• 2004

In this paper, we describe a method that can recognize gestures and evaluate the degree of the gestures from sequential gesture images by using Gesture Feature Space. The previous popular methods based on HMM and neural network have difficulties in recognizing the degree of gesture even though it can classify gesture into some kinds. However, our proposed method can recognize not only posture but also the degree information of the gestures, such as speed and magnitude by calculating distance among the position vectors substituting input and model images in parametric eigenspace. This method which can be applied in various applications such as intelligent interface systems and surveillance systems is a simple and robust recognition algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2310-2316
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• 2010

This paper presents an application of retiming to model checking, a branch of formal verification. Retiming can change the transition relation of a circuit without changing its input-output behaviour by relocating its registers. With the retiming, a given circuit can have a different structure more adequate for model checking. This paper proposes a cost function to reflect the number of registers and the characteristic of its transition relation and develops a heuristic annealing algorithm to search efficiently the circuit structures obtained by retiming. Experimental results show that the proposed method can improve the model checking performance.

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.661-672
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• 2008

In this paper an algorithm, based on extracting a certain target of an image, is proposed that is capable of performing bilevel thresholding of image with multimodal distribution. Each pixel in the image has a membership value which is used to denote the characteristic relationship between the pixel and its belonging region (i.e. the object or background). Using the membership values of image set, a new measurement, which simultaneously measures the measure of fuzziness and the conditional entropy of the image, is calculated. Then, thresholds are found by optimally minimizing calculated measurement. In addition, a fuzzy range is defined to improve the threshold values. The experimental results demonstrate that the proposed approach can select the thresholds automatically and effectively extract the meaningful target from the input image. The resulting image can preserve the object region we target very well.

• Journal of Korea Multimedia Society
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• v.19 no.1
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• pp.68-79
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• 2016

Electromyographic (EMG) signals have been widely used as motion commands of prosthetic arms. Although EMG signals contain meaningful information including the movement intentions of human body, it is difficult to predict the subject's motion by analyzing EMG signals in real-time due to the difficulties in extracting motion information from the signals including a lot of noises inherently. In this paper, four Ag/AgCl electrodes are placed on the surface of the subject's major muscles which are in charge of four upper arm movements (wrist flexion, wrist extension, ulnar deviation, finger flexion) to measure EMG signals corresponding to the movements. The measured signals are sampled using DAQ module and clustered sequentially. The Fuzzy C-Means (FCMs) method calculates the center values of the clustered data group. The fuzzy system designed to detect the upper arm movement intention utilizing the center values as input signals shows about 90% success in classifying the movement intentions.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.371-381
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• 2013

An encryption algorithm is executed to supply data confidentiality using a secret key which is embedded in a crypto device. However, the fault injection attack has been developed to extract the secret key by injecting errors during the encryption processes. Especially, an attacker can find the secret key of block cipher ARIA using about 33 faulty outputs. In this paper, we proposed a countermeasure resistant to the these fault injection attacks by checking the difference value between input and output informations. Using computer simulation, we also verified that the proposed countermeasure has excellent fault detection rate and negligible computational overhead.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.113-116
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• 2007

This paper describes the development of an optimal 3D maze path game as web-based game contents. Client user using web can access and run java applet program with download of java byte code with the independence of hardware system. The optimal 3D maze path game developed in this paper consists of random maze path generation module, selected path input module, weighted optimal path search module, and path comparison module. It enhances the cognition faculty of game users with the comparison of the maze path searched by optimal path search algorithm and the selected maze path by game users.

• Journal of Communications and Networks
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• v.8 no.2
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• pp.169-174
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• 2006

In this paper, the algorithm of a methodology for the calculation of spectrum requirements was implemented. As well, the influence of traffic distribution ratio among radio access technology groups, spectral efficiency, and flexible spectrum usage (FSU) margin was analyzed in terms of the spectrum requirements, with a view toward for future development of international mobile telecommunication (IMT)-2000 and systems beyond IMT-2000. The calculated spectrum requirement in the maximum spectral efficiency case is reduced by approximately 40% compared to a minimum spectral efficiency case. The effect of the distribution ratio on the required spectrum is smaller than the effect of the spectral efficiency. As the flexible spectrum usage margin increases by 1.0 dB, the total spectrum requirement decreases by 0.9 dB. The required spectrum for the market input parameter, ${\rho}$ = 0.5 is 801.63 MHz, while the required spectrum for ${\rho}$ = 1.0 is 6295.4 MHz. This is equivalent to an increase of 785.32 %.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8A
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• pp.768-776
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• 2010

In this paper, we consider a linear precoding for the effective spectrum sharing in multiple-input multiple-output (MIMO) cognitive radio system where a secondary user coexists with primary users. The secondary user employs the orthogonal space time block coding (OSTBC) at the transmitter. Assuming a flat fading channel and a maximum-likelihood receiver, the optimum precoder forces transmission referred to as eigen-beamforming. In this paper, to eliminate the interference, ZF criterion based eigen-beamforming is not only used but also the precoding weight is chosen to cancel the remaining interference. This weight is computed by vector's likelihood. Simulation results show stronger interference suppression capability, better SER performance, and higher capacity than the algorithm in [4].

• 전자공학회논문지 IE
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• v.44 no.4
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• pp.19-25
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• 2007

In this paper, we consider the input-state(I/S) transformation for the time-varying linear system with the uncertainty because of to determine the bounded range of the uncertainty. And we get the time-invarying linear system after the I/S transformation. We present the necessary sufficient condition for the I/S transformation. The transformed system represent the system with the multiple integral. We verify the proposal algorithm via the example and examine.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.407-416
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• 2000

Adaptive digital filtering and noise cancelling technique using a tree structured filter bank are presented to reduce a undesirable aliasing due to the decimation of filtered output and improve the performance in terms of mean-square error and the convergence speed using a aliasing canceller. A signal is split into two subband by analysis filter bank and decimated by decimator and reconstructed by interpolation technique and synthesis filter bank. A variable step-size LMS algorithm is used to improve the convergence speed in case of existing the measurement noise in desired input of filter. It is shown by computer simulation that the proposed subband structure in this paper is superior to conventional subband filter structure in terms of mean-square error and convergence speed.