Punctured(2,1,N)系列卷积码的编码及其Viterbi译码的软件实现

给出了由 (2 ,1,N)系列卷积码作为母码产生的punctured卷积码的编码及其Viterbi译码的软件实现方法 ,从而为各种不同码率的卷积码的编、译码给出了一种通用的实现方法 。

基于CRT的(3,L)-QC-LDPC码构造

对于任意行重L,利用完全确定的方式构造出一类围长为8的(3,L)-LDPC码作为分量码1,构造可快速编码的LDPC码作为分量码2,利用分量码1和分量码2,并结合中国剩余定理(CRT)构造出一类围长至少为8的合成QCLDPC码。该方法构造出来的码字同时具备以上两种特性。仿真结果表明,所构造的码字性能与基于IRCMS算法构造的QC-LDPC码相比,有略微提升,且具有快速编码特性,编码复杂度更低;与具有双对角结构的阵列码相比,性能有了明显提升。在误码率达到10^(-4)时,码字性能大约提高了0.3 dB;与PEG-CRT-LDPC码相比,所构造的码字在低编码复杂度的基础上性能有所提升。

Turbo码的矩阵描述及其对交织器设计的影响

从信号与系统角度研究了Turbo码编码器的工作原理 ,并在这一基础上指出了Turbo码交织器设计过程中应注意的一些问题 .从信号与系统的观点 ,Turbo码编码器的输出码字可以看成是零输入响应和零状态响应的叠加 ,这样可以得出编码器输出码字是由输入信息和几个与编码器结构有关的基本矩阵唯一确定的结论 .利用这样的结论 ,作者讨论了交织器设计过程中满足距离谱特性要求时应遵循的一些设计原则 ,这样可以更好地了解Turbo码的内部结构以及交织器的重要作用 .

斜率因子对Turbo码性能的影响

Turbo码近年来一直是通信领域的研究重点,寻找好的分量码即是一个重要方向。Turbo码分量码编码器采用了以本原多项式作为反馈连接多项式的递归系统卷积码,以获得最大的最小码重和最大的自由距离。本文说明了另一个影响卷积码纠错能力的参量活性突发距离,提出以卷积码的斜率因子为替代参量来分析Turbo码。仿真说明在采用同一个本原多项式作为反馈连接多项式的情况下,分量码的斜率因子越大,则Turbo码的纠错性能相应越好,斜率因子可以作为评价Turbo码性能的另一个重要参数。

结合Turbo码的多级编码调制研究介绍

论文作者在对已有的多级编码调制方案深入研究的基础上 ,进一步研究了Turbo码编码技术 ,并把Turbo码作为分量码结合多级编码调制方案进行了理论研究 .符合当今移动通信的大容量、高可靠性的要求 .论文的主要创新点有 ,通过理论研究 。

A Total Dose Radiation Hardened PDSOI CMOS 3-Line to 8-Line Decoder

The first domestic total dose hardened 2μm partially depleted silicon-on-insulator （PDSOI） CMOS 3-line to 8- line decoder fabricated in SIMOX is demonstrated. The radiation performance is characterized by transistor threshold voltage shifts,circuit static leakage currents,and I-V curves as a function of total dose up to 3× 10^5rad（Si）. The worst case threshold voltage shifts of the front channels are less than 20mV for nMOS transistors at 3 × 10^5rad（Si） and follow-up irradiation and less than 70mV for the pMOS transistors. Furthermore, no significant radiation induced leakage currents and functional degeneration are observed.

IMPROVING THE CAPACITY OF MULTI-CODE MULTIMEDIA CDMA SYSTEM

A novel method for improving the capacity of multi-code multimedia Code Division Mul- tiple Access (CDMA) systems is proposed. By factitiously improving the transmission bit rate of the call, the number of the orthogonal codes used by a user is increased which leads to the decreasing of the interference. Simulation results shows that the proposed scheme results in better throughput than traditional multi-code CDMA systems.

Quantum Key Distribution Scheme Based on Dense Encoding in Entangled States

A quantum key distribution protocol, based on the quantum dense encoding in entangled states, is presented. In this protocol, we introduce an encoding process to encode two classical bits information into one of the four one-qubit unitary operations implemented by Alice and the Bell states measurement implemented by Bob in stead of direct measuring the previously shared Einstein-Podolsky-Rosen pairs by both of the distant parties, Alice and Bob.Considering the practical application we can get the conclusion that our protocol has some advantages. It not only simplifies the measurement which may induce potential errors, but also improves the effectively transmitted rate of the generated qubits by the raw key. Here we also discuss eavesdropping attacks against the scheme and the channel loss.

A NOVEL CAPACITY ANALYZING METHOD FOR MULTIMEDIA CDMA SYSTEMS BASED ON POWER LEVEL ALLOCATION

A novel method is proposed to analyze the capacity of future Code Division Multiple Access （CDMA） systems carrying multimedia services. The power level allocation is firstly investigated to meet each call＇s Bit Error Rate （BER） requirement, then the system capacity is defined from the conditions lbr the existence of the physical meaning of these power levels. Simulation results have shown that the capacity analyzing methods can be well used in the performance evaluation of the system accommodating heterogeneous services and the spectral efficiency of this scheme is higher than the existing ones.

Fluctuation Analysis of Decoy State QKD with Finite Data-Set Size

Decoy state method quantum key distribution (QKD) is one of the promising practical solutions for BB84QKD with coherent light pulses.The number of data-set size in practical QKD protocol is always finite,which will causestatistical fluctuations.In this paper,we apply absolutely statistical fluctuation to amend the yield and error rate of thequantum state.The relationship between exchanged number of quantum signals and key generation rate is analyzed inour simulation,which offers a useful reference for experiment.

The Simulation of High Reynolds Number Cavity Flow Based on Fractional Volumetric Lattice Boltzmann Method

The fractional volumetric lattice Boltzmann method with much better stability was used to simulate two-chmensional cavity flows. Because the effective viscosity was reduced by the fraction factor, it is very effective for simulating high Reynolds number flows. Simulations were carried out on a uniform grids system. The stream lines and the velocity profiles obtained from the simulations agree well with the standard lattice Boltzmann method simulations. Comparisons of detailed flow patterns with other studies via location of vortex centers are also satisfactory.

Measuring-Basis Encrypted Quantum Key Distribution with Four-State Systems

A measuring-basis encrypted quantum key distribution scheme is proposed by using twelve nonorthogohal states in a four-state system and the measuring-basis encryption technique. In this scheme, two bits of classical information can be encoded on one four-state particle and the transmitted particles can be fully used.

A SVM Based Text Steganalysis Algorithm for Spacing Coding

Group distance coding is suitable for secret communication covered by printed documents. However there is no effective method against it. The study found that the hiding method will make group distances of text lines coverage on specified values, and make variances of group distances among N-Window text lines become small. Inspired by the discovery, the research brings out a Support Vector Machine （SVM） based steganalysis algorithm. To avoid the disturbance of large difference among words length from same line, the research only reserves samples whose occurrence-frequencies are ± 10dB of the maximum frequency. The results show that the correct rate of the SVM classifier is higher than 90%.

Constructing Non-binary Asymmetric Quantum Codes via Graphs

The theory of quantum error correcting codes is a primary tool for fighting decoherence and other quantum noise in quantum communication and quantum computation. Recently, the theory of quantum error correcting codes has developed rapidly and been extended to protect quantum information over asymmetric quantum channels, in which phase-shift and qubit-flip errors occur with different probabilities. In this paper, we generalize the construction of symmetric quantum codes via graphs (or matrices) to the asymmetric case, converting the construction of asymmetric quantum codes to finding matrices with some special properties. We also propose some asymmetric quantum Maximal Distance Separable (MDS) codes as examples constructed in this way.

Asymmetrical Quantum Encryption Protocol Based on Quantum Search Algorithm

Quantum cryptography and quantum search algorithm are considered as two important research topics in quantum information science.An asymmetrical quantum encryption protocol based on the properties of quantum one-way function and quantum search algorithm is proposed.Depending on the no-cloning theorem and trapdoor one-way functions of the publickey,the eavesdropper cannot extract any private-information from the public-keys and the ciphertext.Introducing key-generation randomized logarithm to improve security of our proposed protocol,i.e.,one privatekey corresponds to an exponential number of public-keys.Using unitary operations and the single photon measurement,secret messages can be directly sent from the sender to the receiver.The security of the proposed protocol is proved that it is informationtheoretically secure.Furthermore,compared the symmetrical Quantum key distribution,the proposed protocol is not only efficient to reduce additional communication,but also easier to carry out in practice,because no entangled photons and complex operations are required.

A NEW METHOD FOR RESYNCHRONIZATION ATTACK

This paper presents a new method for resynchronization attack, which is the combination of the differential cryptanalysis and algebraic attack. By using the new method one gets a system of linear equations or low-degree equations about initial keys, and the solution of the system of equations results in the recovery of the initial keys. This method has a lower computational complexity and better performance of attack in contrast to the known methods. Accordingly, the design of the resynchronization stream generators should be reconsidered to make them strong enough to avoid our attacks. When implemented to the Toyocrypt, our method gains the computational complexity of O（2^17）, and that of 0（2^67） for LILI-128.

SNP site-drug association prediction algorithm based on denoising variational auto-encoder

Single nucletide polymorphism(SNP)is an important factor for the study of genetic variation in human families and animal and plant strains.Therefore,it is widely used in the study of population genetics and disease related gene.In pharmacogenomics research,identifying the association between SNP site and drug is the key to clinical precision medication,therefore,a predictive model of SNP site and drug association based on denoising variational auto-encoder(DVAE-SVM)is proposed.Firstly,k-mer algorithm is used to construct the initial SNP site feature vector,meanwhile,MACCS molecular fingerprint is introduced to generate the feature vector of the drug module.Then,we use the DVAE to extract the effective features of the initial feature vector of the SNP site.Finally,the effective feature vector of the SNP site and the feature vector of the drug module are fused input to the support vector machines(SVM)to predict the relationship of SNP site and drug module.The results of five-fold cross-validation experiments indicate that the proposed algorithm performs better than random forest(RF)and logistic regression(LR)classification.Further experiments show that compared with the feature extraction algorithms of principal component analysis(PCA),denoising auto-encoder(DAE)and variational auto-encode(VAE),the proposed algorithm has better prediction results.

NOVEL LSCM BEAM-FORMING ALGORITHM IN SMART ANTENNA MC-CDMA SYSTEM

A novel Least Squares Constant Modulus (LSCM) beam-forming algorithm in smart antenna Multi-Carrier Code Division Multiple Access (MC-CDMA) system is proposed in this paper. It adaptively beam-forms the multi-carrier antenna array signal using the LSCM Algorithm (LSCMA), and in the meantime, the beam-formed signals on every sub-carrier are combined by using Orthogonal Restore Combination (ORC), Equal Gain Combination (EGC) or Maximum Ratio Combination (MRC). Then the decision of the combined signals and the spread-code of the expected user are used to re-construct the signals on every sub-carrier. At last, the difference between the re-constructed signal and the output signal of the beam-former is used to con-trol the coefficients of the beam-former. The bit error probability of the proposed algorithm is analyzed. We simulated and compared it with the conventional LSCM beam-forming algorithm. Simulation results show that the proposed algorithm is superior to the latter in Bit Error Rate (BER).

SAR imagery coding based on blocking high frequency energy matching

A new fractal image compression algorithm based on high frequency energy (HFE) partitioning andmatched domain block searching is presented to code synthetic aperture radar (SAR) imagery. In the hybridcoding algorithm, the original SAR image is decomposed to low frequency components and high frequencycomponents by wavelet transform (WT). Then the coder uses HFE of block to partition and searchthe matched domain block for each range block to code the low frequency components. For the high frequencycomponents, a modified embedded zero-tree wavelet coding algorithm is applied. Experiment resultsshow that the proposed coder obtains about 0. 3dB gain when compared to the traditional fractal coderbased on the quadtree partition. Moreover, the subjective visual quality of the reconstructed SAR imageof the proposed coder outperforms that of the traditional fractal coders in the same compression ratio(CR).

Quantization Skipping Method for H.264/AVC Video Coding

This paper presents a quantization skipping method for H. 264/AVC video coding standard. In order to reduce the conputational-cost of quantization process coming from integer discrete cosine transform of H. 264/AVC, a quantization skipping condition is derived by the analysis of integer transform and quantization procedures. The expeerimental results show that the proposed algorithm has the capability to reduce the computional cost about 10% -2.5%.