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991.
992.
提出了一种与DRA编码算法兼容的分层音频编码算法,其中环绕声分层编码采用了声道分类方式,而单声道/立体声分层编码则以残差再编码作为增强层的框架。分析和测试结果表明该DRA分层编码算法能够提供较好的声音质量,可作为信源编码与信道编码和分层调制技术完美结合应用于我国数字音频广播。 相似文献
993.
以数字音视频编码技术标准(Audio Video coding Standard,AVS)为依据,通过对该算法全过程的分析,并结合FPGA硬件平台的结构特点,设计了预测、DCT变换和反DCT变换、量化和反量化、熵编码的全过程。利用FPGA开发工具ISE10.1和仿真工具ModelSim SE 6.2b,并通过Xilinx公司xc5vlx110t-1ff1136平台验证,完成了AVS编码标准P帧从设计到实现的全过程。填补了AVS编码器P帧在FPGA上未实现的空白,同时促进了AVS在FPGA上的发展,并对AVS+和AVS 2发展起到关键性作用。 相似文献
994.
由于无线信道的多径衰落引起的符号间干扰(ISI)极大地影响了接收端的信号质量,为了对抗ISI引起的信号畸变,通常要在接收端进行信道均衡。该文分析了基于MMSE-DFE的Turbo均衡原理并提出两种低复杂度的改进算法。仿真结果表明,这两种算法性能良好。 相似文献
995.
996.
Correspondence analysis and establishment of evaluation model of classification performance indices for a turbo air classifier 下载免费PDF全文
The operational parameters of a turbo air classifier including feeding speed, rotor cage's rotary speed and air inlet velocity affect its classification performance directly, such as cut size, classification precision, classification efficiency, fine powder yield, particle fineness and degree of dispersion. Current methods of optimizing operational parameters and improving the classification performance of a turbo air classifier are almost single objective decision only for one of the classification performance indices. In this paper, the multi‐objective programming (MOP) model on classification performance for a turbo air classifier is established to evaluate these performance indices comprehensively and achieve optimal classification performance. To minimize the effect of repeatability within these classification performance indices, correspondence analysis is applied to determine the evaluation indices of this MOP model. According to correspondence analysis on the fine talc classification experimental data as well as the calcium carbonate classification experimental data, there is a very strong correlation between cut size and D90; there is also a very strong correlation between cut size and fine powder yield. Thus D90 and fine powder yield are filtered out and they aren't discussed in the evaluation model. The variation coefficient method is introduced to calculate weights of the evaluation function, and the dimensionless transformation method is used to eliminate the effects of different dimension. Thus, the optimal solution among the experimental data is obtained through solving the evaluation function. For the talc classification experiments, the optimal operational parameter combinations are: the feeding speed is 40 kg · h–1, the air inlet velocity is 5 m · s–1 and the rotor cage's rotary speed is 1200 ? min–1. The classification performance indices are: cut size is 16.5 μm, classification precision index is 0.59, Newton classification efficiency is 57% and degree of dispersion is 2.13. For the calcium carbonate classification experiments, the optimal operational parameter combinations are: the feeding speed is 92 kg · h–1, the air inlet velocity is 12 m · s–1 and the rotor cage's rotary speed is 1200 ? min–1. The classification performance indices are: cut size is 31.4 μm, classification precision index is 0.74, Newton classification efficiency is 74% and degree of dispersion is 1.27. This evaluation model avoids the limitation of evaluation for the single classification performance index and incomplete information got by the means of single factor experiment of operational parameters. It also provides the quantitative evaluating criteria for classification performance of a turbo air classifier, which offers a theoretical basis for effective production. This multi‐objective programming optimizing method and evaluation model on classification performance can be applied to other dynamic air classifiers as well. 相似文献
997.
Profit‐based exclusive‐or coding algorithm for data retransmission in DVB‐H with a recovery network 下载免费PDF全文
You‐Chiun Wang 《International Journal of Communication Systems》2015,28(9):1580-1597
The digital video broadcasting‐handheld (DVB‐H) standard is developed by European Telecommunications Standards Institute to broadcast digital videos to handheld devices, but data loss is a critical issue due to the broadcast behavior. On the other hand, DVB‐Internet protocol datacasting (DVB‐IPDC) integrates DVB‐H with an Internet protocol‐based wireless network to provide bidirectional communication. We adopt this wireless network to deal with data retransmission and call it a recovery network. The paper argues that network coding can improve retransmission efficiency of the recovery network because DVB‐H packet loss often exhibits high correlation. In addition, DVB‐H packets may be heterogeneous in the sense that they have different importance. According to these two arguments, the paper considers that DVB‐H packets are associated with different profit depending on their importance and proposes an α‐maximum profit network coding problem. It asks the base station in the recovery network to use no more than α coded packets for handheld devices to retrieve the lost DVB‐H packets such that the overall profit is the maximum. An efficient exclusive‐or coding scheme, namely the profit‐based exclusive‐or network coding (PEN) algorithm, is proposed to solve this problem. Extensive simulation results also verify the effectiveness of the PEN algorithm. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
998.
A serial concatenated decoding algorithm with dynamic threshold is proposed for low‐density parity‐check codes with short and medium code lengths. The proposed approach uses a dynamic threshold to select a decoding result from belief propagation decoding and order statistic decoding, which improves the performance of the decoder at a negligible cost. Simulation results show that, under a high SNR region, the proposed concatenated decoder performs better than a serial concatenated decoder without threshold with an Eb/N0 gain of above 0.1 dB. 相似文献
999.
Combining network coding and compressed sensing for error correction in wireless sensor networks 下载免费PDF全文
Siguang Chen Meng Wu Kun Wang Zhixin Sun Weifeng Lu 《International Journal of Communication Systems》2015,28(7):1303-1315
As the spatial and temporal correlations of sensor readings are common in wireless sensor networks, motivated by these features and the drawbacks of network coding (NC), we introduce compressed sensing (CS) into NC scheme and construct a cooperating coding mechanism, which performs over different data fields with a compatible transformation measure for the combination of NC and CS. This cooperating coding scheme can reduce the amount of redundant information transmission significantly, because the temporal and spatial correlations are explored fully. Meanwhile, the erasures and errors are considered simultaneously in relay transmission process; a NC decoding for error control is proposed to correct the erasures and errors. Although the decoding error of NC is existent, this error can be further reduced by the reconstruction process of CS; as a result, the relative recovery error is small enough in the sink. Finally, the reliability and performance analyses confirm that the proposed cooperating coding scheme obtains considerable compression gain as compared with conventional coding scheme of NC and transmits information reliably with high recovery precision. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
1000.
Selective Capture and Quick Detection of Targeting Cells with SERS‐Coding Microsphere Suspension Chip 下载免费PDF全文
Dian Li Yuting Zhang Ruimin Li Jia Guo Changchun Wang Chuanbing Tang 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(18):2200-2208
Circulating tumor cells (CTCs) captured from blood fluid represent recurrent cancers and metastatic lesions to monitor the situation of cancers. We develop surface‐enhanced Raman scattering (SERS)‐coding microsphere suspension chip as a new strategy for fast and efficient capture, recovery, and detection of targeting cancer cells. Using HeLa cells as model CTCs, we first utilize folate as a recognition molecule to be immobilized in magnetic composite microspheres for capturing HeLa cells and attaining high capturing efficacy (up to 95%). After capturing cells, the composite microsphere, which utilizes a disulfide bond as crosslinker in the polymer shell and as a spacer for linking folate, can recycle 90% cells within 20 min eluted by glutathion solution. Taking advantage of the SERS with fingerprint features, we characterize captured/recovered cells with the unique signal of report‐molecule 4‐aminothiophenol through introducing the SERS‐coding microsphere suspension chip to CTCs. Finally, the exploratory experiment of sieving cells shows that the magnetic composite microspheres can selectively capture the HeLa cells from samples of mixed cells, indicating that these magnetic composite microspheres have potential in real blood samples for capturing CTCs. 相似文献