• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1A
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• pp.51-57
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• 2002

In this paper, a simple interpolation technique in a frequency domain is proposed for the discrete Fourier transform(DFT) algorithm. Frequency and phase resolution capabilities of the DFT algorithm can be significantly improved by the proposed interpolation technique without increase of a DFT size(the number of points for the DFT). The new technique uses a diving point in amplitude and phase spectrums. As an application, the technique can be used for joint estimation of fine frequency and phase offsets in burst mode digital transmission. Simulation results show that the joint estimator using the technique is robust to estimation errors.

• Proceedings of the Korea Association of Information Systems Conference
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• 2000.11a
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• pp.1.2-24
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• 2000

The field of neural networks has been a recent surge in activity as a result of progress in developments of efficient training algorithms. For this reason, and coupled with the widespread availability of powerful personal computer hardware for running simulations of networks, there is increasing focus on the potential benefits this field can offer. The neural network may be viewed as an advanced pattern recognition technique and can be applied in many areas such as financial time series forecasting, medical diagnostic expert system and etc.. The intention of this study is to build and implement one simple artificial neural networks hereinafter called ANN. For this purpose, some literature survey was undertaken to understand the structures and algorithms of ANN theoretically. Based on the review of theories about ANN, the system adopted 3-layer back propagation algorithms as its learning algorithm to simulate one case of medical diagnostic model. The adopted ANN algorithm was performed in PC by using turbo PASCAL and many input parameters such as the numbers of layers, the numbers of nodes, the number of cycles for learning, learning rate and momentum term. The system output more or less successful results which nearly agree with goals we assumed. However, the system has some limitations such as the simplicity of the programming structure and the range of parameters it can dealing with. But, this study is useful for understanding general algorithms and applications of ANN system and can be expanded for further refinement for more complex ANN algorithms.

• Journal of Broadcast Engineering
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• v.23 no.3
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• pp.431-436
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• 2018

In this paper, a simple but effective algorithm to reduce the computational complexity of thumbnail generation and to improve image quality without aliasing artifacts is proposed. For the high speed decoding, the proposed algorithm performs partial decoding per $4{\times}4$ boundary in TU(Transform Unit), and preforms TU boundary in PU(Prediction Unit). The proposed method defines the weights based on intra prediction directions and estimates the thumbnail pixel by using that weights. this method remains thumbnail extraction time and improves thumbnail image quality compared with conventional algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.68-75
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• 2013

Recently, there has been introduced various types of pairing computations to implement ID based cryptosystem for mobile ad hoc network. According to spreading the applications of pairing computations, various fault attacks have been proposed. Among them, a counter fault attack has been considered the strongest threat. Thus this paper proposes a new countermeasure to prevent the counter fault attack on Miller's algorithm. The proposed method is able to reduce the possibility of fault propagation by a random index of intermediate values. Additionally, it is difficult to challenge fault attacks on the proposed method since a simple side channel leakage of 'if' branch is eliminated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1661-1672
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• 2000

An immune system has powerful abilities such as memory, recognition and learning how to respond to invading antigens, and has been applied to many engineering algorithms in recent year. In this pap er, the combined optimization algorithm (Immune- Genetic Algorithm: IGA) is proposed for multi-optimization problems by introducing the capability of the immune system that controls the proliferation of clones to the genetic algorithm. The optimizing ability of the proposed combined algorithm is identified by comparing the result of optimization with simple genetic algorithm for two dimensional multi-peak function which have many local optimums. Also the new combined algorithm is applied to minimize the total weight of the shaft and the transmitted forces at the bearings. The inner diameter oil the shaft and the bearing stiffness are chosen as the design variables. The dynamic characteristics are determined by applying the generalized FEM. The results show that the combined algorithm and reduce both the weight of the shaft and the transmitted forces at the bearing with dynamic conatriants.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5C
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• pp.286-294
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• 2011

In most digital cameras, images are obtained by a sensor overlaid by the color filter array (CFA) such as Bayer, demanding a demosaicking procedure to rebuild the full resolution color images. However, due to the nature of sensor, it is necessary to consider denoising step to remove the noise. In this paper, we analyze demosaicking and denoising jointly and show that the proposed method can solve the denoising issue by simple manner, well suppress different level of noises. The proposed algorithm yields comparable performances measured by several image quality assessment (CPSNR, SCIELAB, and FSIM), while the computational cost is low.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2C
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• pp.10-15
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• 2005

In this paper, a simple but fast and reliable technique for the complex dielectric constant measurement of non-magnetic materials is introduced using a measured transmission coefficient (S21) and a genetic algorithm as an inversion process at microwave frequencies. In this experiment, it has been found that the transmission method is less susceptible with the measurement errors than that of the reflection method and the genetic algorithm can be efficiently used as a search technique. The suggested technique is validated with known and unknown conductor-loaded lossy materials and the conductor-loaded PCB at X-band.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.421-424
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• 1998

In this paper, a new on-line local path planning algorithm without local minima problem is proposed. This method, called Window Analysis Method (WAM), is simple and fast, and it helps a robot take a safe path avoiding obstacles in unknown environment. WAM has simulated on the mobile robot to demonstrate its reliability and fesibility.

• The Korean Journal of Applied Statistics
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• v.10 no.2
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• pp.253-260
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• 1997

Various algorithms are investigated with respect to finding the best model-based samples according to criteria such as D-optimality and minimum mean square error. These two criteria are slightly different, but related to each other. Therefore, it is not surprising that these two are producing the almost identical samples. Some simple examples follow and critiques are provided along with directions for further research.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1008-1015
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• 2002

This paper proposes a combinatorial method to compute the global and local solutions of optimization problem. The present hybrid algorithm is the synthesis of a genetic algorithm and a local concentrate search algorithm (simplex method). The hybrid algorithm is not only faster than the standard genetic algorithm, but also gives a more accurate solution. In addition, this algorithm can find both the global and local optimum solutions. An optimization result is presented to demonstrate that the proposed approach successfully focuses on the advantages of global and local searches. Three numerical examples are also presented in this paper to compare with conventional methods.