• Journal of Korean Society of Transportation
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• v.27 no.5
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• pp.113-124
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• 2009

This paper suggests a new approach for providing information for driver safety at signalized intersections. Particularly dangerous situations at signalized intersections such as red-light violations, accelerating through yellow intervals, red-light running, and stopping abruptly due to the dilemma zone problem are considered in this study. This paper presents the development of a dangerous vehicle determination algorithm by collecting real-time vehicle speeds and times from multiple point detectors when the vehicles are traveling during phase-change. For an evaluation of this algorithm, VISSIM is used to perform a real-time multiple detection situation by changing the input data such as various inflow-volume, design speed change, driver perception, and response time. As a result the correct-classification rate is approximately 98.5% and the prediction rate of the algorithm is approximately 88.5%. This paper shows the sensitivity results by changing the input data. This result showed that the new approach can be used to improve safety for signalized intersections.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.155-160
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• 1996

In this paper, we consider the discrete-time known signal detection problem under the presence of additive noise exhibiting weak dependence. We derive the locally optimum, memoryless, and one-memory detector test statistics under a seakly dependent noise model. The performance characteristics of the one-memory detector can achieve almost optimum performance at the expense of only one memory unit under the weakly dependent noise model.

• Korean Journal of Optics and Photonics
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• v.8 no.1
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• pp.42-46
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• 1997

In order to acquire the fluorescence burst signals emitted from single dye molecules that pass through a detection space defined by a confocal microscope, a computer-interfaced photon counter has been fabricated. The maximum count rate is about 80 MHz, which is limited by the counter devices used. Using both the operating computer program written by BASIC and the 486 PC computer, the minimum bin-width of 25 $mutextrm{s}$ has been achieved. The characteristics of fluorescence burst signals emitted from JA22 molecules at about 1$\times$$10^{-11}$m mol/L in ethylene glycol are discussed briefly.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.1
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• pp.48-53
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• 2002

In this paper, we presented a new approach to the recognition of unconstrained handwritten numerals using an improved RBF(Radial Basis Function) Neural Networks. The RBF Neural Networks used Raised Cosine as a basis function to improve discrimination and reduce processing time. The performance of Raised Cosine RBF Neural Networks classifier was evaluated using totally unconstrained handwritten numeral database of Concordia University, Montreal, Canada, and the experimental results showed the recognition rate of 98.05%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.3
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• pp.425-433
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• 1994

The conventional weakly-coupled tap-off for CATV and/or MATV transmitting circuits has been fabricated empirically and experimentally. So, the theoretical analysis or the design method of the conventional one has not been established, the characteristics of which were not good. To solve these problems, we have proposed a modified weakly-coupled freedom in design. This paper describes the design theories and analysis method of the theoretical frequency characteristics of a Modified Weakly-coupled Tap-off with high density of coupling intervals for CATV and/or MATV system. From the theoretical analysis it has been shown that the frequency characteristics of the tap-off proposed here are improved much in comparision with the conventional one. Furthermore, the practical measurements of frequency characteristics for the fabricated circuits show agreement with the theoretical results, and hence, the validity of proposed design and analysis methods has been confirmed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2388-2396
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• 2012

This paper is on an simplified orthogonal projection method which cancel the acoustic echo signals in the stereo acoustic echo canceller. Comparing with the NLMS algorithm which is widely used for simplicity and stability, it shows that this method has the improvement of the convergence performances for signals with the high auto-correlation, and has small computational quantities. To verify the convergence characteristics of the proposed algorithm, we simulated about various input signals. And we compared the results of simulation for this algorithm with the ones for the NLMS algorithm. By these works, it was proved that the stereo acoustic echo canceller adopting the proposed algorithm shows about 3dB more high ERLE than the NLMS algorithm for the white noise signals, and 5dB for the colored voice signals.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.226-237
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• 1998

In recent SATCOM systems, transparent transponders are widely used. The transponder is, however, the most vulnerable part in SATCOM systems against jamming interference. All signals within the transponder bandwidth are frequency-converted and retransmitted with IM(intermodulation) products. In this paper, the method is proposed that makes the SJR(Signal-to-Jammer ratio) better. The bandwidth spreading of the user signal can reduce the jammers effects. The geostationary satellite system is modeled to simulate and to certificate the capability of suppression of jammers by DSSS. If signal is partially-overlapped by jammer and PG(processing gain) is 16.9 [dB] for 2ASK jammer and about 16.8 [dB] for QPSK jammer, when BER is $10^{-3}$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12A
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• pp.1019-1024
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• 2003

In the thesis, we propose a new type of the predistortion linearizer using frequency multiplier The linearizer utilizing the 2nd and 3th harmonic used the individual control of the 3rd and 5th order intermodulation distortion(IMD) component. This structure is composed of wilkinson power combiner for combine and isolation of output signal, 3rd order IMD product controller using doubler and 5th order IMD product controller using tripler. The proposed predistortion linearizer controlled by individual order is obtained for about -16 dBc and 18 dBc of 3rd order and 5th order IMD components, respectively, over the frequency band 870 MHz to 880 MHz at the output power of 34 dBm/tone.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.8
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• pp.859-867
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• 2016

The Global Positioning System is a navigation system that has been developed by the United States for military use. Currently, many countries, including the Republic of Korea, use GPS for civilian and military uses. However, as useful as it is, GPS is vulnerable to its Jamming signal, as the strength of the signal from satellites is very weak. In this paper, a novel jamming signal detection and cancellation method is proposed when a narrow-band jamming signal is included in the GPS received signal. At the GPS receiver, the received signal is transformed to a frequency domain sample by Fast Fourier Transform. In order to suppress the Spectral Leakage, the Blackman-Harris window is used. The proposed jamming signal cancellation algorithm will find the frequency sample with maximum power and null the maximum sample in addition to some lateral samples. If the GPS receiver is designed with FFT of size 128 to 512, it is shown that 42 samples are optimal to cancel the narrow-band jamming signal.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.201-207
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• 2013

The chirp signaling has been mainly used in radar systems due to its good correlation characteristics, and nowadays it is applied to real time locating system(RTLS). The RTLS with chirp signaling was chosen as a standard such as ISO/IEC 24730-5 and IEEE 802.15.4a. In this paper, the performance of a real time locating system with chirp signaling was evaluated and simulated with relative distance error rates. We considered three cases of S/I = -30[dB], -20[dB], and -10[dB] with Rician factor K=10 and K=20. The performance was enhanced with K factor improvement by 25%, 27% and 50% for respective three cases of S/I. As results, in case of S/I < -20[dB], the minimum signal power is required for performance improvement even though the line of sight component is helpful. And also, in case of S/I ${\geq}$ -20[dB], as the line of sight component is stronger the better performance is obtained.