• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1674-1680
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• 2017

In this paper, an embedded system for face authentication, which exploits high-dimensional local binary pattern (LBP) descriptor and joint Bayesian algorithm, is proposed. We also present a feasible embedded system for the proposed algorithm implemented with a Raspberry Pi 3 model B. Computer simulation for performance evaluation of the presented face authentication algorithm is carried out using a face database of 500 persons. The face data of a person consist of 2 images, one for training and the other for test. As performance measures, we exploit score distribution and face authentication time with respect to the dimensions of principal component analysis (PCA). As a result, it is confirmed that an embedded system having a good face authentication performance can be implemented with a relatively low cost under an optimized embedded environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7A
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• pp.641-650
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• 2002

Space-Time Block Code(STBC) provides full diversity gains with simple linear processing at the receiver. Interference Cancellation(IC) techniques in system using STBC improve the capacity and performance of wireless systems with co-channel users. Various IC techniques, Minimum Mean-Squared Error(MMSE) and Zero-Forcing(ZF) algorithms in system with STBC were proposed in the literatures in multiuser environment. The performance of these IC techniques were simulated by assuming perfect channel state information(CSI) of multiuser at the receiver. However, in practice it is difficult to know perfect CSI of multiuser at the receiver. Thus, channel estimation scheme is essential at the receiver. Also SNR estimation scheme is required to operate the MMSE IC algorithm. In this paper, we present estimation schemes of CSI and SNR using training sequences. Through extensive computer simulation, we compare and evaluate the performance of IC techniques using the proposed CSI and SNR estimation techniques.

• The Journal of the Acoustical Society of Korea
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• v.31 no.1
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• pp.1-10
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• 2012

The linear and decision-feedback equalization can mitigate time-varying intersymbol interference (ISI) caused by time-varying multipath propagation for underwater acoustic channels. The perfect elimination of interference components, however, is difficult using the linear equalization and the decision feedback equalizer has an error propagation problem. To overcome these shortcomings, this paper proposes an equalizer mode selection method using training sequences. The proposed method selects an equalization mode corresponding to the signal-to-noise ratio (SNR). If the SNR is low, the proposed system operates the linear equalizer for preventing the error propagation and if the SNR is high, the decision feedback equalizer for eliminating the residual ISI. Therefore, the proposed method can improve the error performance compared to the conventional equalizers. The computer simulation shows the proposed method improves the bit error performance using practical underwater channels responses acquired from the sea experiment.

• Convergence Security Journal
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• v.16 no.6_1
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• pp.43-50
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• 2016

As North Korea has a sufficient ability to attack our society's vulnerable computer network, various large-scale cyber attacks are expected to be tried. North Korea's cyber military strength is known a world-class level. The number of its cyber agents is increasing consistently. Recently North Korea's cyber attack has been made regardless of trick and target. But up to now North Korea's cyber attack is more of an exploration than a real attack. Its purpose was to check how fast Korea found a problem and recovered from it. In future, cyber attack that damages substantially is highly probable. In case of an attack against national infrastructure like traffic, financial and energy services, the extent of the damage will be great beyond imagination. In this paper, characteristics of recent North Korea's cyber attack is addressed in depth and countermeasures such as the enactment of cyber terror prevention law, simulation training enforcement, private and public cooperation system construction, cyber security infrastructure expansion, etc. are proposed.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.424-429
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• 2014

This paper investigates the problem of synchronization of the Pehlivan chaotic system based on sliding mode control and GA. For this, a brief overview of the Pehlivan chaotic system is given. Then, the conventional sliding mode control technique is described and a synchronization method using GA strategy is proposed. The proposed method is that the GA searched the parameters including sliding plane and control gains) selected by the designer in the sliding mode control are searched optimally through the GA. The GA in the MATLAB Toolbox was used and simulation work is shown to illustrate the effectiveness of the synchronization schemes for the chaotic system.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.145-152
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• 2012

Due to the large sizes of streaming media, previous delivery techniques are not providing optimal performance. For this purpose, video proxy server is employed for reducing the bandwidth consumption, network congestion, and network traffic. This paper proposes a fast distributed network file system using state transition model in the media streaming system for efficient utilization of video proxy server. The proposed method is composed of three steps: step 1. Training process using state transition model, step 2. base and decision probability generation, and step 3. storing and deletion based on probability. In addition, storage space of video proxy server is divided into each segment area in order to store the segments efficiently and to avoid the fragmentation. The simulation results show that the proposed method performs better than other methods in terms of hit rate and number of deletion. Therefore, the proposed method provides the lowest user start-up latency and the highest bandwidth saving significantly.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.5
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• pp.99-106
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• 2011

In many applications, wireless sensor networks could be thought as data-centric networks, and the sensor nodes are densely distributed over a large sensor field. The sensor nodes are normally vulnerable in terms of security since they are very often deployed in a hostile environment and open space. In this paper, we propose a scheme for contents-based anomaly detection in wireless sensor networks. In this scheme we use the characteristics of sensor networks where several nodes surrounding an event point can simultaneously detect the phenomenon occurring and the contents detected from these sensors are limited to inside a certain range. The proposed scheme consists of several phases; training, testing and refining phases. Anomaly candidates detected by the distance-based anomaly detection scheme in the testing phase are sent to the refining phase. They are then compared in the sink node with previously collected data set to improve detection performance in the refining phase. Our simulation results suggest the effectiveness of the proposed scheme in this paper evidenced by the improvements of the detection rate and the false positive rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2342-2348
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• 1999

DCT-based codebook design using binary tree was proposed to reduce computation time and to solve the initial codebook problem. In this method, DCT coefficient of training vectors that has maximum variance is to be a split key and the mean of coefficients at the location is used as split threshold, then balanced binary tree for final codebook is formed. However edge degradation appears in the reconstructed image, since the blocks of shade region are frequently selected for codevector. In this paper, we propose DCT-based vector quantization codebook design using unbalanced binary tree. Above all, the node that has the largest split key is splited. So the number of edge codevector can be increased. From the simulation results, this method reconstructs the edge region sincerely and shows higher PSNR than previous methods.

• Journal of the Society of Disaster Information
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• v.13 no.4
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• pp.529-536
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• 2017

In this study, the perceptions were surveyed fire risk and flash flames concerning the firefighters. The results were statistically evaluated according to age, experience and rank. More than 70% of the respondents answered that there is a possibility of unexpected flame exposure in the field of fire, but there was no recognition difference according to age, experience and rank. However, if there is an emergency situation in the field of fire, the survey on the ability to cope with crises showed that there is a difference in perception depending on the age, career, and rank of respondents. From these results, it is expected that strengthening simulation training of unexpected situation will be more urgently required in the future, and measures should be taken to minimize human accidents through improvement of standard operation procedures or supplement of fire suppression education according to unexpected situation.

• Journal of Navigation and Port Research
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• v.26 no.3
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• pp.261-268
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• 2002

At recently, Oil spill accident of large size oiler that happen domestic and outside the country is occured to social impact us as well as economical damage in sea environment. Also, because spread extent of pollution accident is reaching harbor, bay and close water areas, as necessity that traffic control ships are sea place. VTS is changing to concept that control space is magnified gradually. Our country is operated to 14 harbors which is control center. But abroad is operating coastal VTS that do main waterway and coastals to authority dimension. Therefore, necessity that traffic density of ship manages high coastals and ship traffic of waterway to our country is risen. This paper is execute sea traffic survey at Mokop sea areas and sea casualty occurs. It proposal that coastal VTS center field of most suitable and position of radar site.