Space-frequency-Doppler coded OFDM over the time-varying Doppler fading channels

In this paper, space-frequency-Doppler coded OFDM (SFDO-OFDM) scheme over the time-varying Doppler fading channels via the time-frequency duality is proposed. Based on the basis expansion model (BEM) and the time-frequency duality, through the circulant matrix diagonalized processing, the nonlinear time-varying Doppler fading channel is dually converted to the virtual frequency-selective linear channels. With OFDM module, subgrouping the subcarriers in OFDM through the block matrix method and fatherly general complex orthogonal coding (GCOD) on each corresponding block subcarriers, SFDO-OFDM codes for the general multiple input multiple output (MIMO) is thus constructed. And concatenating it with the signal constellation precoding, full maximum diversity gains including the inherent Doppler fading are achieved. Theoretical analysis and corroborating simulation results demonstrate that, comparing with existing Doppler coding alternatives, the proposed scheme can effectively and robustly combat the Doppler fading with high bandwidth efficiency and even lower bit error ratio (BER).     

Robust SVM for Cost-Sensitive Learning

Neural Processing Letters - Although the performance of cost-sensitive support vector machine (CS-SVM) has been demonstrated to approximate to the cost-sensitive Bayes risk, previous CS-SVM methods...     

Sparse learning based on clustering by fast search and find of density peaks

Multimedia Tools and Applications - Clustering by fast search and find of density peaks (CFSFDP) is a novel clustering algorithm proposed in recent years. The algorithm has the advantages of low...     

Graph convolutional networks of reconstructed graph structure with constrained Laplacian rank

Multimedia Tools and Applications - Convolutional neural networks (CNNs) have achieved unprecedented competitiveness in text and two-dimensional image data processing because of its good accuracy...     

无线定位技术中基于多相位的预滤波算法研究

针对接收信号的前端预滤波处理的问题,文章提出了一种基于多相位滤波的预滤波算法,算法有效提高了接收信号噪声功率比,从而可以更精确地估算出定位计算中所需要的定位参数。理论分析表明,多相位滤波的前端预处理技术的采用可以明显提高无线定位精度。     

基于局部结构学习的非线性属性选择算法

针对大多数高维数据之间不仅有相似性,而且还有非线性关系等特点,提出一种基于局部结构学习的非线性属性选择算法。该算法首先通过核函数把数据映射到高维空间,在高维空间中表示出数据属性之间的非线性关系;然后在低维空间中通过局部结构学习来充分挖掘属性之间的相似性,同时通过低秩约束来排除噪声的干扰;最后通过稀疏正则化因子来进行属性选择。其通过核函数映射来找出数据属性之间的非线性关系,运用局部结构学习来找出数据属性之间的相似性,是一种嵌入了局部结构学习的非线性属性选择算法。实验结果表明,该算法相比其他的对比算法,有更好的效果。     

Single-Carrier Single-Block Differential Space–Frequency Coding Transmission Over the Frequency-Selective Fading Channels

In this paper, a single-carrier single-block differential space-frequency block coding scheme for multiple input multiple output frequency-selective fading channels is proposed. In the proposed scheme, an alternative constant modulus single-carrier transmission is adopted, which significantly mitigates the sensitivity to the nonlinear distortion while having comparable lower complexity to the orthogonal frequency division multiplexing modulus. Based on this, subgrouping the signal transmit matrix through the block matrix method and fatherly differential space-frequency complex orthogonal coding on each subblocks, it not only transmits the differentially encoded signal matrix within one symbol block periods regardless of the number of transmit antennas, but also achieves the available spatial and frequency diversities without the requirement of multichannel estimation at the receiver. In the proposed scheme, it is only required that the fading channels keep approximately constant within each subblock during one symbol block transmission period, and thus can be more robust and effective to combat the channel rapidly fading with even lower bit error ratio. Theoretical analysis and corroborating simulation under various channel conditions shows that, our proposed scheme yields superior performance to previously proposed differential schemes.

尿素高压氨泵运行周期短的原因分析和对策

分析尿素装置、三聚氰胺装置联运后高压氨泵高负荷运行时运行周期短、设备本体检修频繁的原因,制定相应措施,保证高压氨泵长周期运行,降低设备备件损耗,实现装置高负荷经济运行。