• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.264-274
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• 2003

This paper presents a direct generalized minimum-variance self tuning controller with a PID structure using neural network which adapts to the changing parameters of the nonlinear system with nonminimum phase behavior, noises and time delays. The self-tuning controller with a PID structure is a combination of the simple structure of a PID controller and the characteristics of a self-tuning controller that can adapt to changes in the environment. The self-tuning control effect is achieved through the RLS (recursive least square) algorithm at the parameter estimation stage as well as through the Robbins-Monro algorithm at the stage of optimizing the design parameter of the controller. The neural network control effect which compensates for nonlinear factor is obtained from the learning algorithm which the learning error between the filtered reference and the auxiliary output of plant becomes zero. Computer simulation has shown that the proposed method works effectively on the nonlinear nonminimum phase system with time delays and changed system parameter.

• The Journal of the Acoustical Society of Korea
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• v.14 no.1
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• pp.31-39
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• 1995

In this paper, we have constructed phoneme discriminant filters [PDF] according to the linear discriminant function. These discriminant filters do not follow the heuristic rules by the experts but the mathematical methods in iterative learning. Proposed system. is based on the piecewise linear classifier and error correction learning method. The segmentation of speech and the classification of phoneme are carried out simutaneously by the PDF. Because each of them operates independently, some speech intervals may have multiple outputs. Therefore, we introduce the unified coefficients by the output unification process. But sometimes the output has a region which shows no response, or insensitive. So we propose time windows and median filters to remove such problems. We have trained this system with the 549 monosyllables uttered 3 times by 3 male speakers. After we detect the endpoint of speech signal using threshold value and zero crossing rate, the vowels and consonants are separated by the PDF, and then selected phoneme passes through the following PDF. Finally this system unifies the outputs for competitive region or insensitive area using time window and median filter.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.963-971
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• 2008

Unsaturated soil mechanics has been often used to find out a cause of failure (tensile failure) of retaining walls and hill slopes containing sandy soils. Checking shear strength is a popular method by considering suction stress developed form pore water menisci among the grains and saturated pockets of pore water under negative pressure. Linear Mohr-Coulomb failure criterion is generally adopted as a failure criterion. However, depending on relative density, stress history, and the magnitude of stress, the failure behavior of sand may not follow linear M-C frictional behavior. For stress in the large compressive ranges, say from tens to hundreds of kPa, the linear M-C criterion is an adequate representation for the shear strength behavior of sand. However, less than tens of kPa, the M-C criterion often can not be accurately represented. Depending on failure criterion, the uniaxial tensile strength is different over 100% relative error. For sand behavior under small compression regimes, therefore, such as under low or zero gravity, or under undergoing tensile failure in the crest area of hill slopes or behind retaining walls, it is important to consider the non-linear behavior.

• Journal of Korean Association for Spatial Structures
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• v.8 no.4
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• pp.81-90
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• 2008

This paper presents a finite element formulation for the three-dimensional hierarchical solid element using Integrals of Legendre polynomials. The proposed hexahedral solid element is composed of four different modes including vertex, edge, face, and internal mode, respectively. The eigenvalue and patch test have been carried out to confirm the zero-energy mode and constant strain condition. In addition to these, a posteriori error estimation has been studied for the p-adaptive finite element analysis that is based on a smoothing technique to compute a post-processed solution from the finite element solution. The uniform p-refinement and non-uniform p-refinement are compared in terms of convergence rate as the number of degree of freedom is increased. The simple cantilever beam is tested to show the performance of the proposed solid element.

• Journal of the Korean School Mathematics Society
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• v.15 no.1
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• pp.53-80
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• 2012

This study was designed to find the characteristics of mathematical errors and discourse in simultaneous equations and inequalities for migrant students from North Korea. 5 sample students participated, who attended in an alternative school for the migrant students from North Korea at the study in Seoul, Korea. A total of 8 lesson units were performed as an extra curriculum activity once a week during the 1st semester, 2011. The results indicated that students showed technical errors, encoding errors, misunderstood symbols, misinterpreted language, and misunderstood Chines characters of Koreans and the discourse levels improved from the zero level to the third level, but the scenes of the third level did not constantly happen. Nevertheless, the components of discourse, explanation & justification, were activated and as a result, evaluation & elaboration increased in ERE pattern on communication.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.105-110
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• 2015

This paper relates with the eualization performance of Constellation Matching-MMA (CM-MMA) in order to the consists of optimum receiver for the minimization of intersymbol interference and additive noise effects that is occurs in the nonlinear communication channel. The error signal were obtained that combines the Constellation Matching technique that inserts the zero point between the signal point of equalizer for improving the residual isi and convergence speed compared to the currently used MMA algorithm. In the initial state of adaptive equalization, it depends on the MMA characteristics mainly. And in the steady state, it depends on the CM characteristics mainly. In order to analyzing the equalization performance, the output signal constellation, residual isi, maximum distortion, MSE and SER were applied, then it were compared with the present MMA algorithm. As a result of computer simulation, the CM-MMA has more better performance in the every performance index, and it was also confirmed that the constellation matching effect can be obtained in the greater than 20dB signal to noise ratio.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.6
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• pp.1-8
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• 2001

Recently, Ryu et al. proposed a multiple target angle tracking algorithm using the angular innovation extracted from the estimated signal subspace. This algorithm obtains the angles of targets and associates data simultaneously. Therefore, it has a simple structure without data association problem. However it requires the calculation of the inverse of a real matrix with dimension (2N+1)${\times}$(2N+1) to obtain the angular innovations of N targets. In this paper, a new linear equation for angular innovation is proposed using the fact that the projection error is zero when the target steering vector is projected onto the signal subspace. As a result, the proposed algorithm dose not require the matrix inversion and is computationally efficient.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.124-130
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• 2016

NDIR $CO_2$ gas sensor was built with ASIC implemented thermopile sensor which included temperature sensor and unique elliptical waveguide structures in this paper. The temperature dependency of dual infrared sensor module ($CO_2$ and reference IR sensors) has been characterized and its output voltage characteristics according to the temperature and gas concentration were proposed for the first time. NDIR $CO_2$ gas and reference IR sensors showed linear output voltages according to the variation of ambient temperatures from 243 K to 333 K and their slopes were 14.2 mV/K and 8.8 mV/K, respectively. The output voltages of temperature sensor also presented a linear dependency according to the ambient temperature and could be described with V(T)=-3.191+0.0148T(V). The output voltage ratio between $CO_2$ and reference IR sensors revealed irrelevant to the changes of ambient temperatures and gave a constant value around 1.6255 with standard deviation 0.008 at 0 ppm. The output voltage of $CO_2$ gas sensor at zero ppm $CO_2$ gas consisted of two components; one is caused by the HPB (half pass-band) of IR filter and the other is attributed to the part of $CO_2$ absorption wavelength. The characteristics of output voltages of $CO_2$ gas sensor could be accurately modeled with three parameters which are dependent upon the ambient temperatures and represented small average error less than 1.5% with 5% standard deviation.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.6
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• pp.860-866
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• 2016

An injection-locked ring phase-locked loop (ILRPLL) using a charge-stored complementary switch (CSCS) injection technique is described in this paper. The ILRPLL exhibits a wider lock range compared to other conventional ILRPLLs, owing to the improvement of the injection effect by the proposed CSCS. A frequency calibration loop and a device mismatch calibration loop force the frequency error to be zero to minimize jitter and reference spur. The prototype chip fabricated in 65-nm CMOS technology achieves a $285-fs_{rms}$ integrated jitter at GHz from the reference clock of 52 MHz while consuming 7.16 mW. The figure-of-merit of the ILRPLL is -242.4 dB.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.2
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• pp.73-80
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• 2003

This Paper Proposes instantaneous following control method to control pulse modulation switching converter by using principle that reset time of integrator is inverse proportion in size of integrator input voltage. proposed control method acts of fixed frequency and control switch calculates time of become turn on and turn off using analog integrator. Duty ratio that express switching time of converter is depended on mean value of switching variable and following time consists in one cycle. Follow to do order exactly stationary state as well as transition state, and controller corrects mean value of control variable and control reference value and control as control error gets into zero. Proposed control method could experimented and know that experiment result and theory are agreeing well through this using the buck converter.