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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of Advanced Navigation Technology
Journal Basic Information
Journal DOI :
The Korea Navigation Institute
Editor in Chief :
Volume & Issues
Volume 5, Issue 2 - Dec 2001
Volume 5, Issue 1 - Jun 2001
Selecting the target year
A Study on the Fast Enrollment of Text-Independent Speaker Verification for Vehicle Security
Lee, Tae-Seung ; Choi, Ho-Jin ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 1~10
Speech has a good characteristics of which car drivers busy to concern with miscellaneous operation can make use in convenient handling and manipulating of devices. By utilizing this, this works proposes a speaker verification method for protecting cars from being stolen and identifying a person trying to access critical on-line services. In this, continuant phonemes recognition which uses language information of speech and MLP(mult-layer perceptron) which has some advantages against previous stochastic methods are adopted. The recognition method, though, involves huge computation amount for learning, so it is somewhat difficult to adopt this in speaker verification application in which speakers should enroll themselves at real time. To relieve this problem, this works presents a solution that introduces speaker cohort models from speaker verification score normalization technique established before, dividing background speakers into small cohorts in advance. As a result, this enables computation burden to be reduced through classifying the enrolling speaker into one of those cohorts and going through enrollment for only that cohort.
A Study on the Performance Improvement of Trellis Coded Orthogonal MC/FH-CDMA System in Wireless Channel
Lee, Moon Seung ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 11~18
In this paper, we evaluated the performance of Orthogonal MC/FH-CDMA system considering the hit of frequency hopping patterns, and obtained the degree of the performance improvement by adopting TCM scheme under frequency selective Rayleigh fading channel. From the performance analysis, it is known that the error performance is improved, since delay time relative to symbol time is reduced as the number of carrier is increased. On the other hand, it is found that BER performance is improved about
degree by adopting TCM scheme, and higher S/N is required if the QoS of voice (BER =
) must be achieved.
A Study on Flight Characteristics and Flight Control Methodology for a Wing In Ground Effect Vehicle
Song, Yongkyu ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 19~25
In this study an analysis on flight characteristics and flight control methods for a wing in ground effect vehicle is made. In order to closely view its nonlinearity a few limit cycles are examined and related to the characteristics of the linearized systems. Several flight control methods are compared for the cruise mode with initial height error and command tracking mode of ascending, cruise, and descending. In comparison performance and the implementation aspects are examined. For the possible control inputs, combinations of elevator, thrust, and flap are considered and LQR-based output command tracking scheme is applied in the control system design.
Tracking of Moving Object using Fuzzy Prediction
Lim, Yong-Ho ; Baek, Joong-Hwan ; Hwang, Soo-Chan ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 26~36
One of the most important problems in time-varying image sequences is the automatic target tracking. This paper proposes a position prediction and tracking technique of moving object using fuzzy prediction. First, the object is segmented from background of the image using accumulative difference image technique. Then centroid of the segmented object is extracted by using the centroid method, and we propose to apply variable size searching window to the object in order to increase the tracking performance. Also, non-linear prediction is required for efficient object tracking. Therefore, in this paper, fuzzy prediction method is proposed for predicting the location of the moving object at next frame. An experimental result shows that the proposed fuzzy prediction system tracks the moving object in stable under various conditions.
A Study on the Performance Analysis and Improvement of Physical Layer for Next Generation ITS/DSRC
Jeong, Jae-Seung ; Park, Sung-Jin ; Lee, Byung-Seub ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 37~44
In this paper, the channel environment for next generation ITS/DSRC which is developed for 10Mbps is modeled with ray tracing technique and, we analyzed BER of OFDM which has an advantage over reducing the effect of ISI with multi-carrier and guard time, occuping bandwidth on 6-ray channel environment. Also, we applied the one-tap equalizer to improve the performance of BER. In case only OFDM is applied with 32 sub-carrier, the result of BER is under
from 10 to 100m if
is more than 23dB. But in case OFDM and one-tap equalizer are applied with 32 sub-carrier,
is required of about 17dB to achieve BER under
Performance Analysis of an Efficient Frame Synchronization Scheme using FFT Window Position Restoration Algorithm for OFDM Systems
Kim, Dong Ok ; Yoon, Chong Ho ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 45~53
We present the frame synchronization scheme using the FFT window position restoration algorithm appropriate for wireless OFDM systems under multipath fading environment. From the restoration of the synchronization parameters of previous several frames, the algorithm can extract the synchronization parameters for the next frames. To analyze the performance of the proposed algorithm, we compare the probability of synchronization failure under time and frequency domains, respectively. From the simulation results, one can see that the algorithm in the time domain shows better performance than in the frequency one, for the
of 6.0dB or more.
Power Spectral Density of Antipodal Ultra Wideband Signal
Kim, Jong Han ; Lee, Jung Suk ; Kim, Yoo Chang ; Kim, Won Hoo ; Kim, Jung Sun ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 54~61
In conventional Ultra Wide Band(UWB) system, it uses Pulse Positioning Modulation Method to modulate data signal. In this paper, however, we derive power spectral density characteristic of time hopped antipodal signal using stochastic process. UWB signal employes Gaussian monopulse and Rayleigh monopulse which pulse width is 0.5 nsec and interval is 5 nsec. But comb line which produces unintentionally could be evidently reduced by the time hopped code, so this code be used to channelize for multiple access and minimize to different communication system.
Performance Analysis and Improvement of Dedicated Short Range Communication System
Park, Ju-Nam ; Cho, Sung-Joon ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 62~73
In this paper, performance of DSRC systems is analyzed with considering the real roads and height of vehicles. The channels are modeled as 2-Ray and 4-Ray with a direct wave and reflected waves by a road and buildings in a physical layer because DSRC keeps LOS propagation characteristics, and the pass loss for each model is calculated respectively. Rician factor is obtained through the calculated path loss on two models for DSRC, and the performance of the systems is analyzed in AWGN and Rician fading channels, Impulsive noise and Rician fading channels respectively. As a result, in Rician fading channels with impulsive noise(A=0.2,
), BER is below
when the distance is farther than 80[m] and 40[m] in 2-Ray model and 4-Ray model respectively. For performance improvement, BCH coding scheme and MRC diversity scheme are adopted.
Performance Enhancement of Combined-IMM/IE Filter for Tracking a Maneuvering Target
Lim, Sang-Seok ; Park, Jung-Ho ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 74~84
Recently a new algorithm which combines advantages of the IMM and IE methods has been suggested. The combined-IMM/IE algorithm could improve the performance to some extent. However, the problem of large increase of tracking error near the maneuver detection due to the sudden maneuver input has not been solved. In this paper, we propose two schemes which can resolve this limitations of combined-IMM/IE algorithm. For illustrations of the performance of the proposed methods. Monte-Carlo simulations are carried out and the results are analyzed.
Control of Flutter using ASTROS
with Smart Structures
Kim, Jong-Sun ; Nam, Changho ;
The Journal of Advanced Navigation Technology, volume 5, issue 1, 2001, Pages 85~96
Recent development of a smart structures module and its successful integration with a multidisciplinary design optimization software
and an Aeroservoelasticity module is presented. A modeled F-16 wing using piezoelectric actuators is used as an example to demonstrate the integrated software capability to design a flutter suppression system. For an active control design, neural network based controller is used for this study. A smart structures module is developed by modifying the existing thermal loads module in
in order to include the effects of the induced strain due to piezoelectric actuation. The control surface/piezoelectric equivalence model principle is developed, which ensures the interchangeability between the control surface force input and the piezoelectric force input to the Aeroservoelasticity modules in
. The results show that the developed controller can increase the flutter speed.