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Low-complexity encoder for LDPC codes in space applications

ELECTRONICS LETTERS 2019年第23期55卷 1241-+页

作者： Chen, Weigang Han, Changcai Yang, Jinsheng Tianjin Univ Sch Microelect Tianjin Peoples R China

A low complexity encoding method and encoder architecture are proposed for the low-density parity-check (LDPC) codes in space applications recommended by Consultant Committee for Space Data Systems. This method uses the generator matrix partition and decomposition to obtain a much smaller dense core matrix. Thus, only one quarter of dense block matrices need to be implemented using the traditional circulant encoding structure. Therefore, the encoder can be implemented with lower computation and storage complexity.

关键词： satellite communication Satellite communication systems generator matrix partition low complexity encoding method Algebra space applications dense core matrix computation complexity Codecs, coders and decoders low-density parity-check codes Consultant Committee for Space Data Systems Codes matrix algebra dense block matrices storage complexity encoder architecture LDPC codes circulant encoding structure encoding parity check codes low-complexity encoder computational complexity

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Analysis of Hydrogen Gas Sensing Characteristics Based on a Grey Polynomial Differential Model (GPDM) Algorithm

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IEEE SENSORS JOURNAL 2011年第9期11卷 1894-1898页

作者： Lin, Kun-Wei Hsu, Chi-Shiang Chaoyang Univ Technol Dept Comp Sci & Informat Engn Taichung 41349 Taiwan Natl Cheng Kung Univ Inst Microelect Dept Elect Engn Tainan 70101 Taiwan

The interesting hydrogen gas sensing characteristics, based on a field-effect transistor (FET)-based sensor, are studied and analyzed. In addition, a new grey algorithm is developed to reduce the computing complexity. From experimental results, the studied device exhibits good hydrogen performance for wide hydrogen concentration detection and widespread operation temperature. For practical applications, it is important to reduce the computational complexity and eliminate data redundancy. In this paper, a new grey polynomial differential model (GPDM) is developed to analyze hydrogen gas sensing properties. Based on the proposed model, the simulated data points are substantially decreased from 4000 points (the measured results) to 68 points (GPDM data). It is worth to note that, the simulated curve still retains the original features of experimental hydrogen transient response. The error rate between the simulated data and experimental results is only of 0.091%. Therefore, the reported GPDM presents the promise on the analysis of hydrogen gas sensing performance by reducing the undesired computing complexity and data redundancy.

关键词： computation complexity data redundancy grey polynomial differential model (GPDM) hydrogen sensor

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Spectrum sidelobe suppression for discrete Fourier transformation-based orthogonal frequency division multiplexing using adjacent subcarriers correlative coding

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IET COMMUNICATIONS 2012年第11期6卷 1374-1381页

作者： Xu, R. Chen, M. Zhang, J. Wu, B. Wang, H. Nanjing Inst Commun Engn Nanjing Jiangsu Peoples R China Southeast Univ Natl Mobile Commun Res Lab Nanjing Jiangsu Peoples R China

The large spectrum sidelobes of orthogonal frequency division multiplexing (OFDM) signal lead to the interference with the licensed user working on the adjacent band in spectrum pooling. The power spectral leakage of discrete Fourier transformation (DFT)-based OFDM systems can be divided into two parts, in-band-out-of-subband (IBOSB) spectral leakage and out-of-band (OOB) spectral leakage. A correlative coding technique is proposed to suppress the IBOSB leakage and redistribute the OOB leakage of DFT-based OFDM signal through the subcarrier coding in the frequency domain with appropriate weighting. The correlation is introduced between adjacent subcarriers and mutual cancellation of the spectrum sidelobes reshapes the spectrum of DFT-based OFDM signal. The optimum weighting factor is obtained through optimisation. Analytical results and simulation show that the proposed coding scheme significantly suppresses the IBOSB leakage in contrast with the common OFDM system and introduces least interference with the licensed user. Furthermore, the carrier-interference ratio (CIR) of OFDM system with correlative coding increases by 3 dB. At the same time, maximum likelihood sequence detection (MLSD) can mostly compensate the bit error rate (BER) degradation caused by error propagation at the expense of introducing a little computation complexity.

关键词： discrete Fourier transforms MLSD spectrum pooling adjacent subcarriers correlative coding DFT-based OFDM systems Optimisation techniques error statistics CIR spectrum sidelobe suppression frequency domain Codes maximum likelihood detection IBOSB leakage orthogonal frequency division multiplexing signal OOB leakage optimisation maximum likelihood sequence detection OFDM modulation codes error propagation Signal detection discrete Fourier transformation computation complexity out-of-band spectral leakage frequency-domain analysis maximum likelihood sequence estimation Integral transforms computational complexity BER in-band-out-of-subband spectral leakage power spectral leakage bit error rate degradation licensed user carrier-interference ratio optimum weighting factor Other topics in statistics

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Successive crosstalk cancellation facing the dynamic situation in very-high-speed digital subscriber line 2 systems

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IET COMMUNICATIONS 2011年第11期5卷 1491-1496页

作者： Ruan, Y. Duengen, M. Rohling, H. Hamburg Univ Technol Inst Telecommun Hamburg Germany

Broadband digital transmission over cable wires, such as in very-high-speed digital subscriber line 2 systems, applies the discrete multitone technique in combination with a bit-loading procedure. The crosstalk interference among the different cables inside a binder is the major performance degradation in the systems. Different crosstalk cancellation schemes considering computation complexity as well as the quality-of-service (QoS) aspect have been investigated to improve the system performance. Nowadays, driven by the newest high-layer applications the QoS requirements are more critical and a dynamic situation happening quite often in reality has to be considered. In this situation, new active cable lines might significantly influence the existing running lines in terms of achieved data rates. Therefore a successive crosstalk cancellation scheme is presented in this study to deal with the dynamic situation. The performance degradation because of the new active lines is predicted. Based on the prediction a line-independent partial cancellation with successive procedure is performed until the QoS requirements are fulfilled again.

关键词： Electromagnetic compatibility and interference telephone interference line-independent partial cancellation Subscriber loops digital subscriber lines system performance quality of service broadband digital transmission broadband networks discrete multitone technique bit-loading procedure Transmission line links and equipment cable wire Telephony crosstalk interference active cable line crosstalk very-high-speed digital subscriber line 2 system telecommunication cables computation complexity crosstalk cancellation communication complexity QoS requirement radiofrequency interference interference suppression

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Turbo equalisation of time varying multipath channel under class-A impulsive noise

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IEE PROCEEDINGS-COMMUNICATIONS 2006年第3期153卷 341-348页

作者： El-Mahdy, A. E. Namazi, N. M. Mil Tech Coll Dept Elect Engn Cairo Egypt Catholic Univ Amer Dept Elect Engn & Comp Sci Washington DC 20064 USA

The paper explores the problem of turbo equalisation and channel estimation under class-A impulsive noise. The channel is a frequency selective fading channel in which its time varying coefficients are expanded into a finite number of basis sequences and time invariant (TI) expansion parameters. Instead of the application of a maximum likelihood (ML) approach in its standard form, the proposed channel estimator is performed by an iterative approach based on the expectation maximisation (EM) algorithm and the steepest descent algorithm. The proposed estimator reduces the complexity of computations resulting from direct application of the ML approach and provides significant performance gain over the algorithms which are efficient in white Gaussian noise. Also, the proposed estimator is suitable for class-A impulsive noise and utilises the soft information obtained from the soft output Viterbi algorithm (SOVA) which is derived under class-A impulsive noise.

关键词： white Gaussian noise SOVA computational complexity computation complexity iterative approach impulse noise basis sequence maximum likelihood decoding turbo codes maximum likelihood sequence estimation expectation-maximisation algorithm time varying multipath channel equalisers turbo equalisation expectation maximisation maximum likelihood approach time-varying channels iterative decoding EM algorithm Communication channel equalisation and identification T invariance Other topics in statistics fading channels time invariant expansion parameter Viterbi decoding white noise Gaussian noise channel estimation ML approach multipath channels soft output Viterbi algorithm Codes frequency selective fading channel class-A impulsive noise Radio links and equipment steepest descent algorithm

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Fast mapping algorithm for histogram to binary set conversion

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PATTERN RECOGNITION LETTERS 2000年第10期21卷 899-906页

作者： Chen, T Chen, LH Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore Monash Univ Sch Comp Sci & Software Engn Clayton Vic 3168 Australia

In this paper, a fast binary set mapping (FBSM) algorithm is proposed for expediting the conversion from histograms to binary color sets. In comparison with the original mapping scheme, significant reduction in the computation complexity can be achieved. Such an efficient mapping algorithm justifies the practical usage of the prefiltering technique in the application to histogram-based image retrieval systems, especially to searching large image databases. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

关键词： computation complexity binary color set histogram-based image retrieval

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Enabling Efficient Data Transmission in Wireless Sensor Networks-Based IoT Application

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Computers, Materials & Continua 2024年第6期79卷 4197-4218页

作者： Ibraheem Al-Hejri Farag Azzedin Sultan Almuhammadi Naeem Firdous Syed Information and Computer Science Department King Fahd University of Petroleum andMineralsDhahran31261Saudi Arabia Center for Cyber Resilience and Trust(CREST) Deakin UniversityGeelong3220Australia

The use of the Internet of Things(IoT)is expanding at an unprecedented scale in many critical applications due to the ability to interconnect and utilize a plethora of wide range of *** critical infrastructure domains like oil and gas supply,intelligent transportation,power grids,and autonomous agriculture,it is essential to guarantee the confidentiality,integrity,and authenticity of data collected and ***,the limited resources coupled with the heterogeneity of IoT devices make it inefficient or sometimes infeasible to achieve secure data transmission using traditional cryptographic ***,designing a lightweight secure data transmission scheme is becoming *** this article,we propose lightweight secure data transmission(LSDT)scheme for IoT *** consists of three phases and utilizes an effective combination of symmetric keys and the Elliptic Curve Menezes-Qu-Vanstone asymmetric key agreement *** design the simulation environment and experiments to evaluate the performance of the LSDT scheme in terms of communication and computation *** and performance analysis indicates that the LSDT scheme is secure,suitable for IoT applications,and performs better in comparison to other related security schemes.

关键词： IoT lightweight computation complexity communication overhead cybersecurity threats threat prevention secure data transmission Wireless Sensor Networks(WSNs) elliptic curve cryptography

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Distributed-program reliability analysis: complexity and efficient algorithms

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IEEE TRANSACTIONS ON RELIABILITY 1999年第1期48卷 87-95页

作者： Lin, MS Chang, MS Chen, DJ Tamsui Oxford Univ Coll Dept Informat Management Taipei 25103 Taiwan Chunghwa Telecommun Training Inst Taipei 22077 Taiwan Natl Chiao Tung Univ Dept Comp Sci & Informat Hsinchu 30050 Taiwan

This paper investigates the problem of distributed-program reliability in various classes of distributed computing systems. This problem is computationally intractable for arbitrary distributed computing systems, even when it is restricted to the class of star distributed computing systems. One solvable case for star distributed computing systems is identified, in which data files are distributed with respective to a consecutive property;a polynomial-time algorithm is developed for this case. A linear-time algorithm is developed to test whether or not an arbitrary star distributed computing system has this consecutive file distribution property. Efficient algorithms may still be sought for computing lower & upper bounds on the distributed program reliability for arbitrary distributed computing systems.

关键词： distributed computing system distributed-program reliability computation complexity

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On the weighting optimisation of the antenna with overlapped subarrays architecture

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IET MICROWAVES ANTENNAS & PROPAGATION 2015年第10期9卷 1035-1044页

作者： Xiong, Zi-Yuan Xu, Zhen-Hai Song, Dan Xiao, Shun-Ping Natl Univ Def Technol State Key Lab Complex Electromagnet Environm Effe Changsha 410073 Hunan Peoples R China

In large array radars, subarray technology can be used to reduce the complexity and cost of system under the restriction of freedom degree. The overlapped subarray, which has high application value, is investigated in this study. For the array antenna with overlapped suabarrays architecture, the traditional weighting methods (such as the two staged tapering method) optimise the subarray pattern and subarray array factor independently, which cannot directly control the final pattern. Based on the analysis of the pattern and the application of overlapped subarrays, a new weighting optimisation method is proposed in this study. By optimising the final antenna pattern directly, the proposed method can obtain the high performance pattern with the lower sidelobe level, the higher taper efficient and the higher gain flatness in the field of view. Moreover, the computation complexity of the new method is very low since its basic algorithm is the linear programming. A set of representative numerical results are reported to validate the effectiveness and potentiality of the proposed method.

关键词： large array radar array antenna antenna radiation patterns computation complexity computational complexity subarray array factor subarray pattern Optimisation techniques antenna arrays linear programming overlapped subarrays architecture Antenna arrays final antenna pattern weighting optimisation method

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Deep ReLU neural networks in high-dimensional approximation

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NEURAL NETWORKS 2021年 142卷 619-635页

作者： Dung, Dinh Nguyen, Van Kien Vietnam Natl Univ Informat Technol Inst Hanoi 144 Xuan Thuy Hanoi Vietnam Univ Transport & Commun Fac Basic Sci 3 Cau Giay St Hanoi Vietnam

We study the computation complexity of deep ReLU (Rectified Linear Unit) neural networks for the approximation of functions from the Holder-Zygmund space of mixed smoothness defined on the d-dimensional unit cube when the dimension d may be very large. The approximation error is measured in the norm of isotropic Sobolev space. For every function f from the Holder-Zygmund space of mixed smoothness, we explicitly construct a deep ReLU neural network having an output that approximates f with a prescribed accuracy epsilon, and prove tight dimension-dependent upper and lower bounds of the computation complexity of the approximation, characterized as the size and depth of this deep ReLU neural network, explicitly in d and epsilon. The proof of these results in particular, relies on the approximation by sparse-grid sampling recovery based on the Faber series. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Deep ReLU neural network computation complexity High-dimensional approximation Sparse-grid sampling Continuous piece-wise linear functions Holder-Zygmund space of mixed smoothness

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