• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.255-258
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• 2005

A blind-mode integer frequency offset estimation algorithm is proposed for an OFDM system. Imperfect integer frequency offset estimation causes ambiguity in the data sub-carrier position. Morelli's blind integer frequency offiet estimation algorithm exploits the likelihood function by comparing the power in sub-carriers. It, however, shows performance degradation when there is the fractional frequency offset. The proposed algorithm solves this by using interpolation in the frequency domain. In this algorithm, it is exploited that the effect of the frequency offset is shown as a shift of power spectrum. By calculating the covariance of over-sampled samples, most approximate samples to integer point are obtained. It enables integer frequency offset estimation less affected by fractional frequency offset.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.216-222
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• 2002

Brake Moan is a laud and strong noise occurring at any vehicle speed over 2 mph as a low frequency in below 600Hz. In this study, we targeted to shift the unstable mode that causes the brake moan from the moats frequency range to sufficiently higher frequency range to avoid the moan phenomenon. We simulated the finite element model and found out the nodes in which the brake moan occurs the most and we regarded the boundary and its relationship between the brake pad and the rotor as a spring coefficient k. With the binary set of the spring coefficient k, we finally used genetic algorithm (GA) to get the optimal topology of the brake pad and its shape to avoid the brake moan. The final result remarkably shows that genetic algorithm can be used in topology optimization procedures requiring complex eigenvalue problems.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1037-1043
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• 2004

In this paper, a new fault detection and isolation algorithm fur inertial sensor system is proposed. To identify the inertial sensor fault, single antenna GPS receiver is used as an effective redundancy source. To use GPS receiver as redundancy for the inertial sensors, the algorithm to estimate the attitude and acceleration using single antenna GPS receiver is adopted. By using Doppler shift of carrier phase signal and kinetic characteristics of aircraft, attitude information of aircraft can be obtained at the coordinated flight condition. Based on this idea, fault diagnosis algorithm for inertial sensors using single antenna GPS based attitude is proposed. For more effective FDI, decision variables considering the aircraft maneuver are proposed. The effectiveness of the proposed algorithm is verified through the numerical simulations.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.82-85
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• 1998

Because ATM was originally designed for the optical fiber environment with bit error rate(BER) of 10-11, it is difficult to maintain ATM cell extraction capability in wireless environment where BER ranges from 10-6 to 10-3. Therefore, it must be proposed the algorithm of ATM cell extraction in wereless environment. In this paper, the frame structure and synchronization algorithm satisfyling the above condition are explained, and the new ASIC implementation method of this algorithm is proposed. The known method using shift register needs so many gates that it is not suitable for ASIC implementation. But in the proposed method, a considerable reduction in gate count can be achieved by using random access memory.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.813-814
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• 2008

In this paper, we propose a new tracking algorithm which uses weighted sum of color bin's centroids to find the main centroid of the target. The weights are determined by the proportion of colors of the target and by the colors of background. That is, A color which has high occupation in forming the target is highly weighted and a color which has low occupation is lowly weighted. Moreover, the proposed algorithm prevent track failure by lowering the weight of the colors which forms the background. Therefore, the proposed algorithm performs stable tracking inspite of occlusion and existence of confusing backgrounds.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.133-136
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• 1997

This paper explores the optimal design methodology for auto lever using a genetic algorithm. Component of auto lever has been designed sequentially in the industry, but this study presents the novel design method to consider the design parameters of components simultaneously. The genetic algorithm approach is described to determine a set of design parameters for auto lever. The authors have attempted to model the design problem with the objective of minimizing the angle variation of detent spring subject to constraints such as modulus of elasticity of steel, geometry of shift pipe, and stiffness of spring. This method can give the better alternative.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.185-188
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• 1999

An estimation algorithm for vehicle driving load has been proposed in this paper. Driving load is an important factor in a vehicle's longitudinal motion control. An approach using an observer is introduced to estimate driving load based on inexpensive RPM sensors currently being used in production vehicles. Also, a torque estimation technique using nonlinear characteristic functions has been incorporated in this estimation algorithm. Using a nonlinear full vehicle simulation model, we study the effect of the driving load on longitudinal vehicle motion, and the performance of the estimation algorithm has been evaluated. The proposed estimation algorithm has good performance and robustness over uncertainties in the system parameters. An accurate estimate of the driving load can be very helpful in the development of advance vehicle control systems such as intelligent cruise control systems, CW/CA systems and smooth shift control systems.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.961-964
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• 2000

With the advance of wireless communications technology, mobile communications has become more convenient than ever. However because of the openness of wireless communications, how to protect the privacy between communicating parties is becoming a very important issue. In this paper an authentication and encryption algorithm of the GSM network for roaming user is proposed. In the proposed algorithms, we use a new hash function for user authentication and LFSR (Linear Feedback Shift Register) based stream cipher for message encryption and decryption. Each algorithm is programmed with C language and simulated on IBM-PC system and we analyze the randomness properties of the developed algorithm using statistical analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.922-925
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• 2005

This article describes a FM modulation algorithm to increase the measurement speed by increasing the beat frequency of the laser without acousto-optic modulator(AOM) in the heterodyne laser interferometer. The proposed algorithm can increase the beat frequency of the heterodyne laser which limit the measurement speed by adjusting a carrier frequency through electronic circuit, while AOM is used to shift the frequency of the heterodyne laser in conventional method. Electronic circuit is constructed to modulate the signals from a laser interferometer and a waveform generator. The brier analysis, the measurement scheme of the system, and the experimental results using a Zeeman-stabilized He-Ne laser are presented. They demonstrate that the proposed algorithm is proven to enhance the measurement speed limit by increasing the beat frequency of the heterodyne laser.

• Journal of Korea Multimedia Society
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• v.24 no.11
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• pp.1461-1471
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• 2021

This paper presents a light exposure correction algorithm for less pleasant images, acquired with a light metering failure. Since conventional tone mapping and gamma correction methods adopt a function mapping with the same range of input and output, the results are pleasurable for almost symmetric distributions to their intensity average. However, their corrections gave insufficient outputs for asymmetric cases at either bright or dark regions. Also, histogram modification approaches show good results on varied pattern images, but these generate unintentional noises at flat regions because of the compulsive shift of the intensity distribution. Therefore, in order to sufficient corrections for both bright and dark areas, the proposed algorithm calculates the gamma coefficients using primary parameters extracted from the global distribution. And the fusion weights are adaptively determined with complementary parameters, considering the classification information of a binary segmentation. As the result, the proposed algorithm can obtain a good output about both the symmetric and the asymmetric distribution images even with severe exposure values.