无线通信中MIMO-OFDM技术的研究现状和展望

简要介绍了MIMO-OFDM技术的基本原理,重点讨论了空频编码、接收机设计、多用户系统等方面的研究现状以及未来研究的领域。     

On Small World Semiplanes with Generalised Schubert Cells

The well known “real-life examples” of small world graphs, including the graph of binary relation: “two persons on the earth know each other” contains cliques, so they have cycles of order 3 and 4. Some problems of Computer Science require explicit construction of regular algebraic graphs with small diameter but without small cycles. The well known examples here are generalised polygons, which are small world algebraic graphs i.e. graphs with the diameter d≤clog  _k−1(v), where v is order, k is the degree and c is the independent constant, semiplanes (regular bipartite graphs without cycles of order 4); graphs that can be homomorphically mapped onto the ordinary polygons. The problem of the existence of regular graphs satisfying these conditions with the degree ≥k and the diameter ≥d for each pair k≥3 and d≥3 is addressed in the paper. This problem is positively solved via the explicit construction. Generalised Schubert cells are defined in the spirit of Gelfand-Macpherson theorem for the Grassmanian. Constructed graph, induced on the generalised largest Schubert cells, is isomorphic to the well-known Wenger’s graph. We prove that the family of edge-transitive q-regular Wenger graphs of order 2q ⁿ , where integer n≥2 and q is prime power, q≥n, q>2 is a family of small world semiplanes. We observe the applications of some classes of small world graphs without small cycles to Cryptography and Coding Theory.     

Pause or No Pause？--Prosodic Phrase Boundaries Revisited

This study presents evidence from analyses of the acoustic parameters of fluent continuous speech to show that within-paragraph prosodic phrase boundaries are related more to contrasts of neighborhood prosodic states rather than between-phrase pause durations; prosodic states receive more constraints from higher level discourse information. By revising a modular acoustic model by Tseng＇s hierarchical prosodic phrase grouping framework and examining the much varied prosodic phrase （PPh） boundary B3 within speech paragraph, we show that statistical accounts of layered contributions reveal distinct contrasts between boundary immediate duration and intensity patterns irrespective of pause duration. Contrasts of FO contour patterns were also observed in these locations. Evidence was also obtained to illustrate how PPh boundary states are specified more by higher level discourse information than by lower level prosodic word construction. These combined results suggest that contrastive neighboring prosodic states are more significant cues to PPh boundaries than boundary pause duration. The results also help explain why in fluent speech between-phrase pause durations vary greatly, and can be applied to automatic speech segmentation.     

波形变换域浊音语音的一种分帧自适应编码算法

波形变换编码算法中，影响语音质量的主要因素是浊音语音编码进产生的量化误差。本在Ｍｏｚｅｒ算法基础上，提出一种波形变换域分帧自适应编码新算法。采用这种算法用近代的单片数字信号处理器对编译码容易到实时处理，而短时量化信噪比的平均值可达６ｄＢ。     

一种新的机床模块化设计编码方法

从模块化设计的目的出发，提出模块化设计应侧重功能与组合两个方面，而机床功能在模块上体现为模块的特性参数。因此，模块的编码应当引入上述两个方面内容。整个设计通过采用人机交互方式，拼装模块组合机床；通过借助计算机，自动匹配模块来实现。此外，还可以作进一步的后续处理。     

二值化误差扩散的编码算法

提出了基于误差扩散的二值化编码算法，此算法在进行二值化误差扩散的同时加入给定的编码，即用变化的阈值代替固定的阈值，使单纯的二值化算法具有嵌入编码的能力，并能有效地、可靠地嵌入和提取编码．经过对样图进行具体的算法实施，其嵌入编码都能被正确无误地提取出来．结果表明该算法是可行、有效的，具有很好的实用性．     

计划与口语质量

计划能够对实际的语言运用产生很大的影响。计划与口语准确性、流利性和复杂性有密切的关系 ,对于外语教学尤其是英语口语教学有一定的启发意义     

海豚等动物神经系统处理多普勒信号的一种可能性方案

海豚、蝙蝠等动物具有功能强大的生物声纳，生物神经系统处理多普勒效应的网络结构可能会有多种形式.对这类生物的神经系统信号处理机制及结构的研究，将能为信息处理提供新的视角.根据序空间神经编码理论，构建了一个生物神经回路处理多普勒信号.经计算机仿真可知，该生物神经网络运算速度快、分辨率高，并能处理任意的连续变频率多普勒信号.所研究的仅由1—2个神经元组成的网络结构是最简单的，由于网络只有一级神经元的延时，保证了处理的快速性，在神经元输出10个脉冲的情况下分辨率可达7^-10. 关键词： 多普勒效应 海豚 神经编码 神经脉冲序列     

Photonic Implementation of Quantum Computation Algorithm Based on Spatial Coding

Several implementation methods of quantum computation algorithm by conventional computer have been explored for large-scale emulation. Due to the lack of quantum effects, these methods generally require exponential growth of the size of the hardware with increase of the number of qubits. In this paper, the spatial coding, which is an effective digital optical computing technique, is studied as an efficient implementation method of quantum computation algorithms. In the proposed scheme, quantum information is represented by the intensity and the phase of elemental cells. We confirmed correct operation of the quantum teleportation algorithm by computer simulation. We also demonstrated a photonic implementation of some of the quantum gates experimentally.     

Polarization synchronization in quasi-isotropic CO2 lasers

We present experimental evidence of the in-phase and out-phase synchronization of the polarization in two coupled quasi-isotropic CO₂ lasers. We also show, by means of numerical simulations, how it is possible to retrieve message encoded in the polarization of the master laser from the observation of the slave laser alone, due to the synchronization.