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乘积码的迭代译码算法 被引量:2
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作者 欧劲昭 叶梧 +1 位作者 黄娟 尹俊勋 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2000年第11期30-34,共5页
对乘积码的迭代译码算法进行研究 ,给出以BCH(15,7,5)为分量码的乘积码在译码器选择不同参数时的仿真结果 .还研究了译码参数对译码器性能的影响 ,得出有关这些参数选择的有用结论 ,并对进一步提高译码器性能给出一些可行的方法 .
关键词 乘积码 信道编码 迭代译码算法 译码参数
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Improved Sinusoid Analysis and Post-Processing in Parametric Audio Coding
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作者 周宏 陈健 《Journal of Shanghai Jiaotong university(Science)》 EI 2003年第2期163-168,共6页
This paper proposed improvements to the low bit rate parametric audio coder with sinusoid model as its kernel. Firstly, we propose a new method to effectively order and select the perceptually most important sinusoids... This paper proposed improvements to the low bit rate parametric audio coder with sinusoid model as its kernel. Firstly, we propose a new method to effectively order and select the perceptually most important sinusoids. The sinusoid which contributes most to the reduction of overall NMR is chosen. Combined with our improved parametric psychoacoustic model and advanced peak riddling techniques, the number of sinusoids required can be greatly reduced and the coding efficiency can be greatly enhanced. A lightweight version is also given to reduce the amount of computation with only little sacrifice of performance. Secondly, we propose two enhancement techniques for sinusoid synthesis: bandwidth enhancement and line enhancement. With little overhead, the effective bandwidth can be extended one more octave; the timbre tends to sound much brighter, thicker and more beautiful. 展开更多
关键词 parametric audio coding SINUSOID POST-PROCESSING
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Cryptanalysis of Key Exchange Protocol Based on Tensor Ergodic Problem
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作者 Chunsheng Gu Youyu Gu +2 位作者 Peizhong Shi Chunpeng Ge Zhenjun Jing 《China Communications》 SCIE CSCD 2018年第10期172-181,共10页
Recently, Mao, Zhang, Wu et al. constructed two key exchange(KE) protocols based on tensor ergodic problem(TEP). Although they conjectured that these constructions can potentially resist quantum computing attack, they... Recently, Mao, Zhang, Wu et al. constructed two key exchange(KE) protocols based on tensor ergodic problem(TEP). Although they conjectured that these constructions can potentially resist quantum computing attack, they did not provide a rigorous security proof for their KE protocols. In this paper, applying the properties of ergodic matrix, we first present a polynomial time algorithm to solve the TEP problem using O(n^6) arithmetic operations in the finite field, where n is the security parameter. Then, applying this polynomial time algorithm, we generate a common shared key for two TEP-based KE constructions, respectively. In addition, we also provide a polynomial time algorithm with O(n^6) arithmetic operations that directly recovers the plaintext from a ciphertext for the KE-based encryption scheme. Thus, the TEP-based KE protocols and their corresponding encryption schemes are insecure. 展开更多
关键词 key exchange KE-based encryption tensor decomposition ergodic matrix
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Real-Code Genetic Algorithm for Ground State Energies of Hydrogenic Donors in GaAs-(Ga,Al)As Quantum Dots
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作者 YAN Hai-Qing TANG Chen +1 位作者 LIU Ming ZHANG Hao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第4X期727-730,共4页
We present a global optimization method, called the real-code genetic algorithm (RGA), to the ground state energies. The proposed method does not require partial derivatives with respect to each variational parameter ... We present a global optimization method, called the real-code genetic algorithm (RGA), to the ground state energies. The proposed method does not require partial derivatives with respect to each variational parameter or solving an eigenequation, so the present method overcomes the major difficulties of the variational method. RGAs also do not require coding and encoding procedures, so the computation time and complexity are reduced. The ground state energies of hydrogenic donors in GaAs-(Ga,Al)As quantum dots have been calculated for a range of the radius of the quantum dot radii of practical interest. They are compared with those obtained by the variational method. The results obtained demonstrate the proposed method is simple, accurate, and easy implement. 展开更多
关键词 ground state energy quantum dots real-code genetic algorithms
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