• Title, Summary, Keyword: Error Detection

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A Modified Viterbi Algorithm for Word Boundary Detection Error Compensation (단어 경계 검출 오류 보정을 위한 수정된 비터비 알고리즘)

  • Chung, Hoon;Chung, Ik-Joo
    • The Journal of the Acoustical Society of Korea
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    • v.26 no.1E
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    • pp.21-26
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    • 2007
  • In this paper, we propose a modified Viterbi algorithm to compensate for endpoint detection error during the decoding phase of an isolated word recognition task. Since the conventional Viterbi algorithm explores only the search space whose boundaries are fixed to the endpoints of the segmented utterance by the endpoint detector, the recognition performance is highly dependent on the accuracy level of endpoint detection. Inaccurately segmented word boundaries lead directly to recognition error. In order to relax the degradation of recognition accuracy due to endpoint detection error, we describe an unconstrained search of word boundaries and present an algorithm to explore the search space with efficiency. The proposed algorithm was evaluated by performing a variety of simulated endpoint detection error cases on an isolated word recognition task. The proposed algorithm reduced the Word Error Rate (WER) considerably, from 84.4% to 10.6%, while consuming only a little more computation power.

Quadrature-detection-error Compensation in a Sinusoidally Modulated Optical Interferometer Using Digital Signal Processing

  • Hwang, Jeong-hwan;Park, Chang-Soo
    • Current Optics and Photonics
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    • v.3 no.3
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    • pp.204-209
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    • 2019
  • In an optical interferometer that uses sinusoidal modulation and quadrature detection, the amplitude and offset of the interference signal vary with time, even without considering system noise. As a result, the circular Lissajous figure becomes elliptical, with wide lines. We propose and experimentally demonstrate a method for compensating quadrature detection error, based on digital signal processing to deal with scaling and fitting. In scaling, fluctuations in the amplitudes of in-phase and quadrature signals are compensated, and the scaled signals are fitted to a Lissajous unit circle. To do so, we scale the average fluctuation, remove the offset, and fit the ellipse to a unit circle. Our measurements of a target moving with uniform velocity show that we reduce quadrature detection error from 5 to 2 nanometers.

Obstacle Position Detection on an Inclined Plane Using Randomized Hough Transform and Corner Detection (랜덤하프변환과 코너추출을 이용한 경사면의 장애물 위치 탐색)

  • Hwang, Sun-Min;Lee, Min-Cheol
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.5
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    • pp.419-428
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    • 2011
  • This paper suggests a judgement method for an inclined plane before entrance of it and the detection of obstacle position. Main idea is started from the assumption that obstacle is always on the bottom plane, and corner appears at this position. The process to detect the obstacle consists of three steps. First the 3D data using stereo matching is acquired to detect an obstacle. Second a bottom plane is extracted by using limit condition. Last the obstacle position is found by using Harris corner detection. Obstacle position detection on an inclined plane was verified by outdoor and indoor experiment. In error analysis, it is confirmed that an average error of obstacle detection in outdoor was larger than the error in indoor but the error are within about 0.030 m. This method will be applied to unmanned vehicles to navigate under various environment.

Low-Complexity MIMO Detection Algorithm with Adaptive Interference Mitigation in DL MU-MIMO Systems with Quantization Error

  • Park, Jangyong;Kim, Minjoon;Kim, Hyunsub;Jung, Yunho;Kim, Jaeseok
    • Journal of Communications and Networks
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    • v.18 no.2
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    • pp.210-217
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    • 2016
  • In this paper, we propose a low complexity multiple-input multiple-output (MIMO) detection algorithm with adaptive interference mitigation in downlink multiuser MIMO (DL MU-MIMO) systems with quantization error of the channel state information (CSI) feedback. In DL MU-MIMO systems using the imperfect precoding matrix caused by quantization error of the CSI feedback, the station receives the desired signal as well as the residual interference signal. Therefore, a complexMIMO detection algorithm with interference mitigation is required for mitigating the residual interference. To reduce the computational complexity, we propose a MIMO detection algorithm with adaptive interference mitigation. The proposed algorithm adaptively mitigates the residual interference by using the maximum likelihood detection (MLD) error criterion (MEC). We derive a theoretical MEC by using the MLD error condition and a practical MEC by approximating the theoretical MEC. In conclusion, the proposed algorithm adaptively performs interference mitigation when satisfying the practical MEC. Simulation results show that the proposed algorithm reduces the computational complexity and has the same performance, compared to the generalized sphere decoder, which always performs interference mitigation.

Effective Error Detection Method for Video using Fragile Watermark (연성 워터마크를 이용한 비디오의 효율적인 에러 검출 방법)

  • Hwang, Young-Hooi;Jeon, Byeung-Woo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.39 no.6
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    • pp.602-611
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    • 2002
  • Recent advances in technology have resulted in rapid growth in mobile communication. With this explosive growth, reliable transmission and error resilient technique become increasingly necessary to offer high quality multimedia service. The success of error resilient techniques at decoder sensitively depends on error detection performance. Therefore, this paper proposes a computationally very simple and efficient error detection technique using fragile watermark for real-time video communication. To balance between image quality degradation and error detection efficiency, fragile watermark is embedded only in least significant bits of selected transform coefficients. The proposed method is workable without additional bit in video bitstream and can be implemented very efficiently. This method will be useful in video communication in error prone environment such as wireless channel.

Motion Compensation Based on Signal Processing Method for Airborne SAR

  • Song, Won-Gyu;Shin, Hee-Sub;Lee, Ho-Jin;Lim, Jong-Tae
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1199-1201
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    • 2005
  • In the synthetic aperture radar (SAR) system, the motion error is the main phase error sources and the motion compensation is very important. The phase gradient autofocus (PGA) is a state of art technique for phase error correction of SAR. It exploits the redundancy of the phase-error information among range bins by selecting the strongest scatter for each range bin and synthesizes them. The motivation of this paper is based on the observation that the redundancy of phase error is also among the cross-range direction. Moreover, the proposed method applies the weighting function to better utilize the phase error information. The validity of the proposed scheme for PGA is tested with some numerical simulation.

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Error Detection Architecture for Modular Operations (Modular 연산에 대한 오류 탐지)

  • Kim, Chang Han;Chang, Nam Su
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.27 no.2
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    • pp.193-199
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    • 2017
  • In this paper, we proposed an architecture of error detection in $Z_N$ operations using $Z_{(2^r-1)N}$. The error detection can be simply constructed in hardware. The hardware overheads are only 50% and 1% with respectively space and time complexity. The architecture is very efficient because it is detection 99% for 1 bit fault. For 2 bit fault, it is detection 99% and 50% with respective r=2 and r=3.

On the Improvement of Error Performance in the Differential Detector for 3-h CPM (3-h CPM 차동 검파기의 오율 성능 개선)

  • 홍의식;한영열
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.3
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    • pp.240-246
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    • 1992
  • In the paper, the differential detection techniques of 3-h CPM signals whose modulation index is varied periodically are proposed and their error performances are analyzed. We select the modulation index sets which are proper to the differential detection and propose the differential detectors which detect symbol with 3 bits per smapling period of 3T and detect a bit per sampling period of T. Applying the nonredundant error correction circuit and viterbi algorithm to differential detection of 3-h CPM. We ascertain the error performances are improved.

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Error-detection-coding-aided iterative hard decision interference cancellation for MIMO systems with HARQ

  • Park, Sangjoon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.3
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    • pp.1016-1030
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    • 2018
  • In this paper, an error-detection-coding-aided iterative hard decision interference cancellation (EDC-IHIC) scheme for multiple-input multiple-output systems employing hybrid automatic repeat request (HARQ) for multi-packet transmission is developed and investigated. In the EDC-IHIC scheme, only packets identified as error-free by the EDC are submitted to the interference cancellation (IC) stage for cancellation from the received signals. Therefore, the possibility of error propagation, including inter-transmission error propagation, can be eliminated using EDC-IHIC. Because EDC must be implemented in systems that employ HARQ to determine packet retransmission, error propagation can be prevented without the need for additional redundancy. The results of simulations conducted herein verify that the EDC-IHIC scheme outperforms conventional hard decision IC schemes in terms of the packet error rate in various environments.

A Novel Error Detection Algorithm Based on the Structural Pattern of LZ78-Compression Data (LZ78 압축 데이터의 구조적 패턴에 기반한 새로운 오류 검출 알고리즘)

  • Gong, Myongsik;Kwon, Beom;Kim, Jinwoo;Lee, Sanghoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.11
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    • pp.1356-1363
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    • 2016
  • In this paper, we propose a novel error detection algorithm for LZ78-compressed data. The conventional error detection method adds a certain number of parity bits in transmission, and the receiver checks the number of bits representing '1' to detect the errors. These conventional methods use additional bits resulting in increased redundancy in the compressed data which results in reduced effectiveness of the final compressed data. In this paper, we propose error detection algorithm using the structural properties of LZ78 compression without using additional bits in the compressed data. The simulation results show that the error detection ratio of the proposed algorithm is about 1.3 times better for error detection than conventional algorithms.