• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.7
• /
• pp.689-694
• /
• 2008

This paper proposes a roll rate estimation method for spinning vehicles. The carrier phase and frequency variations caused by spinning of vehicles are observed and the roll rate estimator is designed on the observation. The roll rate estimator consists of phase detector and zero crossing counter. The phase detector computes phase variation using in-phase and quadrature value from the correlator. By using zero crossing counter, the roll rate can be estimated since the output of phase detector is changed in proportion to the roll rate. Experiment a results show that estimated roll rate error is smaller than 0.0578Hz.

• Journal of the Chungcheong Mathematical Society
• /
• v.19 no.2
• /
• pp.133-139
• /
• 2006

By combining the classical Newton's method with the pseudo-secant method, pseudo-secant-Newton's method is constructed and its order and rate of convergence are investigated. Given a function $f:\mathbb{R}{\rightarrow}\mathbb{R}$ that has a simple real zero ${\alpha}$ and is sufficiently smooth in a small neighborhood of ${\alpha}$, the convergence behavior is analyzed near ${\alpha}$ for pseudo-secant-Newton's method. The order of convergence is shown to be cubic and the rate of convergence is proven to be $\(\frac{f^{{\prime}{\prime}}(\alpha)}{2f^{\prime}(\alpha)}\)^2$. Numerical experiments show the validity of the theory presented here and are confirmed via high-precision programming in Mathematica.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.10
• /
• pp.542-549
• /
• 2004

The conventional fault location algorithms based on the travelling waves have an inherent problem. In cases of the close-up faults occurring near the relaying point and of the faults having zero degree inception angle of voltage signals, the conventional algorithms can not estimate an accurate fault distance. It is because the shapes of travelling waves are near sinusoidal in those cases. A new method solving this problem is presented in this paper. An FIR(Finite Impulse response) filter which makes high frequency components prominent and makes the power frequency component and dc-offset attenuated is used. With this method, the cross-correlation peak is to be very clear when a close-up fault or a fault having near zero-degree inception angle occurs. The cross-correlation peaks can be clearly distinguished and accurate fault location is practically possible consequently. A series of simulation studies using EMTP(Electromagnetic Transients Program) show that the proposed algorithm can calculate an accurate fault distance having maximum 2% or less error.

• Proceedings of the KIEE Conference
• /
• 1999.07f
• /
• pp.2529-2533
• /
• 1999

This paper proposes a modified hysteresis current control method based on space vector modulation. The proposed method differs from former works in that it uses effective voltage vectors instead of zero vectors while not significantly increasing the circuit complexity. The circuit uses outer band that is slightly wider than the usual current limit band (inner band) to detect the phase of current command and thereby the region information. The comparator output signals associated with the inner and outer band are used to determine the proper voltage vector that minimizes the current error and number of switching, with simple logic circuitry. The utilization of effective voltage vector is of particular importance when the ac-side emf is relatively large. Both the simulation and experiment show that the proposed method is more effective than the conventional one that uses zero vectors, in reducing the number of switching over a range of ac-side emf variation.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.12 no.5
• /
• pp.636-643
• /
• 2009

NHC means that the velocity of the vehicle in the plane perpendicular to the forward direction is almost zero. The main error source of NHC is the mounting misalignment which is the difference between the body frame of a land vehicle and the sensor frame of an inertial measurement unit. This paper suggests new NHC algorithm that can reduce position errors by real-time estimation of mounting misalignment. Then NHC/ZUPT integrated land navigation system is designed and its performances are analyzed by simulations with van test data. Simulation results show that the proposed NHC/ZUPT land navigation system improves navigation accuracy regardless of misalignment angle and is very useful when SDINS operates stand-alone for land vehicle navigation with large mounting misalignment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1995.06a
• /
• pp.155-157
• /
• 1995

New formulas for McClellan transform parameters for the design of 2-D Zero-phase FIR fan filters are optimally derived under the integral squared error(ISE) criterion. By imposing the constraint that F(0,0)=coswc, where F($.$) is the McClellan transform and w is the cutoff frequency of the 1-D prototype filter, the ISE is directly minimized without modifying it and, as a consequence, closed-form formulas for the McClellan transform parameters are obtained. It is shows that these formulas lead to a very efficient design for 2-D zero-phase FIR fan filters.

• International journal of advanced smart convergence
• /
• v.7 no.3
• /
• pp.37-43
• /
• 2018

Lattice-reduction (LR) techniques have been developed for signal detection in spatial multiplexing multiple input multiple output (MIMO) systems to obtain the largest diversity gain. Thus, an LR-assisted zero-forcing (ZF) receiver can achieve the maximum diversity gain in spatial multiplexing MIMO systems. In this paper, a simplified analysis of the achievable diversity gain is presented by fitting the channel coefficients lattice-reduced by a complex Lenstra-Lenstra-$Lov{\acute{a}}z$ (LLL) algorithm into approximated Gaussian random variables. It will be shown that the maximum diversity gain corresponding to two times the number of receive antennas can be achieved by the LR-based ZF detector. In addition, the approximated bit error rate (BER) expression is also derived. Finally, the analytical BER performance is comparatively studied with the simulated results.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.5
• /
• pp.1225-1239
• /
• 2016

We investigate pediatric tumor incidence data collected by the Florida Association for Pediatric Tumor program using various models commonly used in disease mapping analysis. Particularly, we consider Poisson normal models with various conditional autoregressive structure for spatial dependence, a zero-in ated component to capture excess zero counts and a spatio-temporal model to capture spatial and temporal dependence, together. We found that intrinsic conditional autoregressive model provides the smallest Deviance Information Criterion (DIC) among the models when only spatial dependence is considered. On the other hand, adding an autoregressive structure over time decreases DIC over the model without time dependence component. We adopt weighted ranks squared error loss to identify high risk regions which provides similar results with other researchers who have worked on the same data set (e.g. Zhang et al., 2014; Wang and Rodriguez, 2014). Our results, thus, provide additional statistical support on those identied high risk regions discovered by the other researchers.

• Electronics and Telecommunications Trends
• /
• v.36 no.1
• /
• pp.22-31
• /
• 2021

In this thesis, we examine the development status of autonomous mobility services using various artificial intelligence algorithms and propose a solution by combining edge and cloud computing to overcome technical difficulties. A fully autonomous vehicle with enhanced safety and ethics can be implemented using the proposed solution. In addition, for the future of 2035, we present a new concept that enables two- and three-dimensional movement via cooperation between ecofriendly, low-noise, and modular fully autonomous vehicles. The zero-error autonomous driving system will safely and conveniently transport people, goods, and services without time and space constraints and contribute to the autonomous mobility services that are free from movement in connection with various mobility.

• ETRI Journal
• /
• v.44 no.1
• /
• pp.117-124
• /
• 2022

In this paper, the performance of precoding-aided differential spatial modulation (PDSM) systems with optimal transmit antenna subset (TAS) selection is examined analytically. The average bit error rate (ABER) performance of the optimal TAS selection-based PDSM systems using a zero-forcing (ZF) precoder is evaluated using theoretical upper bound and Monte Carlo simulations. Simulation results validate the analysis and demonstrate a performance penalty < 2.6 dB compared with precoding-aided spatial modulation (PSM) with optimal TAS selection. The performance analysis reveals a transmit diversity gain of (N_T-N_R+1) for the ZF-based PDSM (ZF-PDSM) systems that employ TAS selection with N_T transmit antennas, N_S selected transmit antennas, and N_R receive antennas. It is also shown that reducing the number of activated transmit antennas via optimal TAS selection in the ZF-PDSM systems degrades ABER performance. In addition, the impacts of channel estimation errors on the performance of the ZF-PDSM system with TAS selection are evaluated, and the performance of this system is compared with that of ZF-based PSM with TAS selection.