• 한국소음진동공학회논문집
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• 제16권5호
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• pp.495-502
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• 2006

A fault diagnosis method is developed in this study using automaton through quantization of vibration signals for normal and faulty conditions, respectively. Automaton is a kind of qualitative model which describes the system behaviour at the level of abstraction. The system behavior was extracted from the probability of the output sequence of vibration signals. The sequence was made as vibration levels by reconstructing the originally measured vibration signals. As an example, a fault diagnosis for the bearing of ATM machine was done, which detected the bearing fault with confident level compared to any other existing methods of kurtosis or spectrum analysis.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.216-219
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• 2003

In this paper, we present performance analysis of an IEEE P802.15.3a high rate wireless personal area network transceiver. This physical layer standard uses QOSK as its sub-channel modulation scheme and orthogonal frequency domain modulation (OFDM) for sub-bands. OFDM is used for each sub-band so that multi-path effects are absorbed by equalizer and guard, and fading can be approximately modeled as additive white Gaussian noise. In multi-band ultra-wideband system, DAC quantization error is important noise source since high resolution conversion cannot be used due to high power consumption. Simulation result shows that, to get 640-Mbps throughput, at least 5-bits precision is necessary to maintain bit-error rate under 10$\^$-2/, which can be lowered, with channel coding, to 10$\^$-6/ that is the bit-error rate required by IEEE 802.15 upper protocol layer, in 4-meter LOS fading channel.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1985년도 추계학술발표회 논문집
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• pp.220-223
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• 1985

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.667-670
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• 2000

This paper provides a heuristic theory for modeling and analysis of vector quantization effects in 2-dimensional subband filter banks. This model is used as the basis for optimal filter bank design. The scalar non-linear gain-plus-additive noise quantization model can be used to represent each vector quantizer in 2-band subband codec. The validity and accuracy and of this analytic model is confirmed by comparing the calculated model quantization errors with actual simulation of the optimum LBG vector quantizer. Numerical design examples for the optimum separable paraunitary filter banks are suggested in this paper.

• 소음진동
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• 제10권2호
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• pp.331-337
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• 2000

The necessity of diagnosis of the rotating machinery which is widely used in the industry is increasing. Many research has been conducted to manipulate field vibration signal data for diagnosing the fault of designated machinery. As the pattern recognition tool of that signal, neural network which use usually back-propagation algorithm was used in the diagnosis of rotating machinery. In this paper, self-organizing feature map(SOFM) which is unsupervised learning algorithm is used in the abnormal defect diagnosis of rotating machinery and then learning vector quantization(LVQ) which is supervised learning algorithm is used to improve the quality of the classifier decision regions.

• 한국통신학회논문지
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• 제23권9A호
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• pp.2271-2281
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• 1998

The wordlength optimization for the analog-to-digital converter in DS-CDMA receivers is very important for the efficient implementation of front-end digital demodulator blocks. Wideband CDMA systems reqire a very fast acquisition time, thus they prefer the matched filter base dreceiver architecture.However, the matched filter should san very long chips, and as a results, requires a large number of gates and a high-power consumption. In this paper, the quantization effects on the acquisition performance of the matched filter is analyzed stochastically. The quantization is modeled as a series of saturation and digitization procedures, because the distortion due to the saturation is signal dependent and causes very different effects when compared with that of the, random, digitization noise. Numerical results are obtained to show the optimum saturaton limit of the quantizer for a given wordlength. This analysis can give a guide to low-cost and low-powr digital implementations and assurance of the system performance without intensive simulations.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.131-137
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• 1997

In this paper, we propose an efficient motion adaptive 3-dimensional (3D) video coding algorithm using 3D subband coding (3D-SBC) and lattice vector quantization (LVQ) for low bit rate. Instead of splitting input video sequences into the fixed number of subbands along the temporal axes, we decompose them into temporal subbands of variable size according to motions in frames. Each spatio-temporally splitted 7 subbands are partitioned by quadtree technique and coded with lattice vector quantization(LVQ). The simulation results show 0.1∼4.3dB gain over H.261 in peak signal to noise ratio (PSNR) at low bit rate(64Kbps).

• 전자공학회논문지C
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• 제36C권11호
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• pp.84-91
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• 1999

본 논문에서는 삼각함수와 양자화 된 삼각 퍼지함수를 가중퍼지평균(WFM: Weighted Fuzzy Mean)에 적용하여 비교하였다 또한 잡음의 특성에 따라서 영상에 포함된 잡음을 완전히 제거할 수 없는 단점을 개선하기 위하여, 계층적 구조의 결정기반 신경회로망(DBNN: Decision Based Neural Network)에 퍼지알고리즘을 적용하여서, 영상에 포함된 잡음을 제거하고 동시에 정보의 손실을 최소화하고 최적의 정보를 얻을 수 있는 고속 가중 퍼지결정 신경회로망(FDNN: fuzzy Decision Neural Network)을 구현하였다. 그리고 모의실험을 통하여 WFM과 FDNN의 성능을 비교하였으며, 보트(boats)의 영상에 대한 평균자승오차 (MSE:Mean Square Error)를 비교한 결과 제안된 FDNN이 우수함을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.321-340
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• 2016

The Compressive Video Sensing (CVS) is a useful technology for wireless systems requiring simple encoders but handling more complex decoders, and its rate-distortion performance is highly affected by the quantization of measurements and reconstruction of video frame, which motivates us to presents the Space-Time Quantization (ST-Q) and Motion-Aligned Reconstruction (MA-R) in this paper to both improve the performance of CVS system. The ST-Q removes the space-time redundancy in the measurement vector to reduce the amount of bits required to encode the video frame, and it also guarantees a low quantization error due to the fact that the high frequency of small values close to zero in the predictive residuals limits the intensity of quantizing noise. The MA-R constructs the Multi-Hypothesis (MH) matrix by selecting the temporal neighbors along the motion trajectory of current to-be-reconstructed block to improve the accuracy of prediction, and besides it reduces the computational complexity of motion estimation by the extraction of static area and 3-D Recursive Search (3DRS). Extensive experiments validate that the significant improvements is achieved by ST-Q in the rate-distortion as compared with the existing quantization methods, and the MA-R improves both the objective and the subjective quality of the reconstructed video frame. Combined with ST-Q and MA-R, the CVS system obtains a significant rate-distortion performance gain when compared with the existing CS-based video codecs.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.444-447
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• 2004

SNR(Signal to Noise Ratio) is one of the most important performance for the electro-optical camera system. This paper shows not only the SNR analyses for the MSC system, which is the payload in the KOMPSAT2 satellite, but also the trials for its improvement in the electronics circuit design. The MSC deals with one panchromatic band and four multi-spectral bands. The SNR analyses are performed based on the MSC design for the each band and assuming that the defined radiance reached directly to the sensor entrance pupil. In the SNR calculation, shot noise, dark current noise, analog electronics noise and ADC quantization noise are considered as noise sources. In these noise sources, especially, the electronics noise depends on the camera electronics design. This paper shows the camera electronics design to increase SNR and its test results as well as the SNR analyses.