• Journal of the Institute of Electronics Engineers of Korea TC
• /
• 제48권1호
• /
• pp.92-96
• /
• 2011

In this paper, we present a bandpass filter (BPF) based on composite right-/left-handed (CRLH) structure for improving the linearity of the power amplifier. The proposed BPF consist of the inter-digit signal line on the top plane and the complementary split ring resonator (CSRR) on the bottom plane, respectively. The insertion loss is minimized at operation frequency and the 2nd harmonic is suppressed by the bandpass filter using the CRLH structure, respectively. The output power of 33 dBm, the 2nd harmonic of -53.527 dBc, 3rd inter-modulation distortion of -36.16 dBc was obtained at 2.14 GHz, respectively. Compared with the reference power amplifier, the 2nd harmonic of 16 dB and 3rd inter-modulation distortion of 12 dB have been improved at 2.14 GHz, respectively.

• Journal of the Korea Society of Computer and Information
• /
• 제16권4호
• /
• pp.23-28
• /
• 2011

Ultrasound images for the abdominal muscles are complicated enough to have difficulty in interpreting their results. For better interpretation, magnifying the original image is necessary but its magnified image could be deteriorated and suffer from information loss. Thus, in this paper, we propose a magnifying method that reduces the gap between the original image and the magnified one in quality using a fuzzy method with weights for its brightness and interpolation. The proposed method extracts information of pixels in magnified image that have most similar characteristics of the original one by applying fuzzy membership function. In the process, the difference in the brightness between pixels of the magnified image and the original one using bilinear interpolation method and the weight value using the interpolation from multiplied values of four pixels are supplied to the fuzzy membership function. In this experiment, the proposed method reduces the cloudy phenomenon appears commonly compared to the bilinear interpolation method among those qualitative issues of image interpretation.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• 제15권1호
• /
• pp.33-38
• /
• 2003

Turbidity meter calibrations were conducted using bottom sediment and suspended material collected with a vertical array of sediment traps at the coastal water off Gaduk Island. Compared to the bottom sediment comprising sand fraction of approximately 6％, trapped suspended material was composed entirely of silt and clay fractions and showed a tendency to get finer as elevation from the sea-bed increases. Slope parameter of linear regression due to bottom sediment was of minimum value and values of those due to suspended material increased gradually as the height of sediment trap increases (i.e., sediment size decreases). This result shows that turbidity meter calibration using bottom sediment can cause an overestimation error in the calculation of suspended sediment concentration and that the error can reach up to 25% in case of this study. Therefore, it is suggested that the use of a corrected calibration curve based on grain size distribution of suspended material instead of bottom sediment may reduce the measurement error of suspended sediment concentration.

• Journal of the Korea Society for Simulation
• /
• 제26권3호
• /
• pp.105-113
• /
• 2017

This study considers an optimal investment planning for improving survivability from an air threat in the layered air defense system. To establish an optimization model, we first represent the layered air defense system as a network model, and then, present two optimization models minimizing the failure probability of counteracting an air threat subject to budget limitation, in which one deals with whether to invest and the other enables continuous investment on the subset of nodes. Nonlinear objective functions are linearized using log function, and we suggest dynamic programming algorithm and linear programing for solving the proposed models. After designing a layered air defense system based on a virtual scenario, we solve the two optimization problems and analyze the corresponding optimal solutions. This provides necessity and an approach for an effective investment planning of the layered air defense system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• 제37권6A호
• /
• pp.473-479
• /
• 2012

In this paper, blind equalization technique using Gaussian two-cluster model is proposed. The proposed approach, by modeling the received M-QAM signals as Gaussian distributed two-cluster, minimizes the computational complexity and enhances the reliability of the signal estimates. In addition, by using a nonlinear estimator with variable parameters to estimate the transmitted signal, and by selectively applying the reduced constellation and the original constellation when estimating the signals, the reliability of the signal estimation was further improved. As a result, the proposed approach has improved the performance while reducing the complexity of the equalizer. Through computer simulations for blind equalization of higher-order signals of 64-QAM, it was confirmed that the proposed method showed better performance than traditional approaches.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• 제35권1C호
• /
• pp.33-39
• /
• 2010

Correntropy is a generalized correlation function that contains higher order moments of the probability density function (PDF) than the conventional moment expansions. The criterion maximizing cross-correntropy (MCC) of two different random variables has yielded superior performance particularly in nonlinear, non-Gaussian signal processing comparing to mean squared error criterion. In this paper we propose a new blind equalization algorithm based on cross-correntropy criterion which uses, as two variables, equalizer output PDF and Parzen PDF estimate of a set of randomly generated symbols that complies with the transmitted symbol PDF. The performance of the proposed algorithm based on MCC is compared with the Euclidian distance minimization.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 한국신호처리시스템학회 2005년도 추계학술대회 논문집
• /
• pp.353-356
• /
• 2005

In this paper, the proposed $gamma({\gamma})$ line system is developed for reducing the error between non-linear gamma curve produced by a formula and result produced by hardware implementation. The proposed algorithm and system is based on the specific gamma value 2.2, namely the formula is represented by {0,1}$^{2.2}$ and the bit width of input and out data is 10bit. In order to reduce the error, the system is using least squares polynomial of the numerical method which is calculating the best fitting polynomial through a set of points. The proposed gamma line is consisting of nine kinds of quadratic equations, each with their own overlap sections to get more precise. Based on the algorithm verified by $MATLAB^{TM}$ 7.0, the proposed system is implemented by using Verilog-HDL. The proposed system has 2 clock latency; 1 result per clock. The error range (LSB) is -4 and +3. Its standard deviation is 1.287956238. The total gate count of system is 2,083 gates and the maximum timing is 15.56[ns].

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제18권1호
• /
• pp.579-584
• /
• 2017

The damper oil seal of a high-speed railway vehicle is made from nitrile butadiene rubber (NBR) in order to prevent lubricant from leaking into the damper and to stop harmful contaminants from entering the external environment while in service. Oil leakage through the seal primarily occurs from fatigue failure of the damper. Cumulative damage of the seal occurs due to the contact force between the rod and the rubber during movement due to track irregularities and cants, among other factors. Thus, the design of the oil seal should minimize the maximum principal strain at weak points. In this study, the optimal cross section of the damper oil seal was found using the multi-island genetic algorithm method to improve the durability of the damper. The optimal shape of the oil seal was derived using process automation and design optimization software. Nonlinear material properties for finite element analysis (FEA) of the rubber were determined by Marlow's model. The nonlinear FEA confirmed that the maximum principal strain at the oil leakage point was decreased 24% between the initial design and the optimum design.

• Journal of the Korean Geotechnical Society
• /
• 제32권4호
• /
• pp.5-14
• /
• 2016

Numerical simulation of dynamic soil-pile-structure interaction embedded in a dry sand was carried out. 3D model of the dynamic centrifuge model tests was formulated in a time domain to consider nonlinear behavior of soil using the finite difference method program, FLAC3D. As a modeling methodology, Mohr-Coulomb criteria was adopted as soil constitutive model. Soil nonlinearity was considered by adopting the hysteretic damping model, and an interface model which can simulate separation and slip between soil and pile was adopted. Simplified continuum modeling (Kim et al., 2012) was used as boundary condition to reduce analysis time. Calibration process for numerical modeling results and test results was performed through the parametric study. Verification process was then performed by comparing numerical modeling results with another test results. Based on the calibration and validation procedure, it is identified that proposed modeling method can properly simulate dynamic behavior of soil-pile system in dry condition.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• 제11권2호
• /
• pp.265-272
• /
• 2007

This proposed gamma (${\gamma}$) correction system is developed to reduce the difference between non-linear gamma curve produced by a typical formula and result produced by the proposed algorithm. In order to reduce the difference, the proposed system is using the Least Squares Polynomial which is calculating the best fitting polynomial through a set of points which is sampled. Each system is consisting of continuous several kinds of equations and having their own overlap sections to get more precise. Based on the algorithm verified by MATLAB, the proposed systems are implemented by using Verilog-HDL. This paper will compare the previous algorithm of gamma system such as Existing system with Seed Table with the latest that such as Proposed system. The former and the latter system have 1, 2 clock latency; each 1 result per clock. Because each of the error range (LSB) is $1{\sim}+1,\;0{\sim}+36$, we can how that Proposed system is improved. Under the condition of SAMSUNG STD90 0.35 worst case, each gate count is 2,063, 2,564 gates and each maximum data arrival time is 29.05[ns], 17.52[ns], respectively.