可重编程正交频分复用水声调制解调技术进展*

随着海洋探索和军事应用的迫切需求,水声通信需要向高数据率、高可靠性方向发展。正交频分复用技术被视为水声高速通信的新途径,并被成功应用于水声通信,在水声通信中展现了其优越性。高度灵活的自适应平台的发展,激发了可重编程水声调制解调器的发展,以适应不同实验/应用场景的需求。文中从带宽、调制方案、数据率、传输距离、误码率方面,介绍了国内外研究机构对可重编程正交频分复用水声调制解调器研究的进展,并对其中的技术进行概述。最后对可重编程正交频分复用水声调制解调器进行了展望。认为可重编程正交频分复用水声调制解调器需要的是分块接收处理的自适应实时扩展平台,同时也坚信水声网络的发展和需求必将推动智能水声通信的发展。     

一种新型光分插复用器及其在WDM自愈环网中的应用

提出了一种新型的基于FBG和光环形器的双向光分插/复用器结构.它的结构简单,网络配置灵活,而且可实现单纤双向环网中功率放大.结合该OADM,首次给出了在单纤双向DNI环网实现保护的策略,指出此结构在各种WDM网络中实现单纤环网保护的可行性.     

Reconfigurable mesh-based inter-chip optical interconnection network for distributed-memory multiprocessor system

A 4×4 reconfigurable mesh-based inter-chip optical interconnection network is reported for distributed-memory multiprocessor system and the experiment confirmed that the data rate in each channel could reach above 3.125 Gbps, which would be a good solution to solve the communication bottlenecks between processors. Each node of this reconfigurable mesh could realize 15 internal connection patterns to complete the interconnections of processors. Besides, this mesh interconnect network via ultra-high bandwidth waveguides embedded in EOPCB can realize flexible multiprocessor system architecture options.     

Transmission-type reconfigurable metasurface for linear-to-circular and linear-to-linear polarization conversions

We present a transmission-type polarization conversion metamaterial (PCM) whose functions can be dynamically switched among the linear-to-circular (LTC) and linear-to-linear (LTL) polarization conversions. The proposed PCM consists of a grating, a polarization conversion surface and a reconfigurable polarization selective surface incorporated with PIN diodes. By changing the states of diodes, the PCM can achieve the reconfigurable manipulations for incident waves. The Fabry-Pérot (F-P) resonances excited by the PCM contribute to the polarization conversions, as is illustrated. Moreover, through establishing the F-P-like cavity model and analyzing the electric field components of the transmitted waves, the conditions for realizing LTC polarization conversion are revealed, which can guide the construction of PCM. The prototype of PCM is fabricated and measured, which can achieve LTC and LTL polarization conversions within 3.31-3.56 GHz and 2.76-4.24 GHz, respectively, the polarization conversion ratios of two functions are higher than 0.95. The measurement results are in agreement with the simulation data.     

Reconfigurable microwave photonic transversal filter using a variable gain tilt filter

A novel and simple technique to realize reconfigurable microwave photonic transversal filter is presented. In the proposed method, a multi-wavelength source and a dispersive medium are applied to achieve multiple taps; and an electro-optic ceramic material-based variable gain tilt filter (VGTF) is utilized to control the tap weights of the filter. The VGTF is computer-controlled via a universal serial bus interface, which enables real-time reconfiguration of the filter. Filter responses with different passband bandwidth and different sidelobe suppression can be achieved. Compared with previous approaches, the given method features in less optical components involved and faster response speed. A three-tap reconfigurable filter with sub-millisecond response speed is experimentally demonstrated.     

Expandable quantum key distribution networks based on secret bits comparison

A scheme of quantum network based on multiuser differential phase shift quantum key distribution system (DPS-QKD) is proposed. In this quantum network, arbitrary two users can achieve secret bits sharing by point-to-multipoint quantum key distribution and secret bits comparison. A protocol of secret bits sharing between arbitrary two users is presented. This network can implement secret bits distribution over 200 km with higher key generation rate by today's technologies. In theory, the capacity of user numbers in this network is unlimited. Hence, our proposed quantum network can serve for a metropolitan QKD network. A wide area QKD network can be constructed with this metropolitan QKD network.     

大尺寸薄壳物体表面的三维光学自动检测

报道一种大型薄壳物体的智能光学三维测量以及自动在线检测方法,利用三节点光学测量传感器网络实现了大型薄壳物体内外表面数据的三维重建、特征尺寸获取及计算机辅助设计(CAD)模型的比对.提出一种有效的三维多节点传感器测量网络的系统标定方法,可同时完成整体测量系统在大尺度测量空间的现场标定以及各个三维节点测量传感器的标定.提出...     

具备重构能力的三模冗余器载计算机研究

器载计算机是航天器电气系统的重要组成部分,需要冗余技术来满足其高可靠性运行要求。为了保证航天器上计算机在出现异常故障时仍能正常工作,对传统三模容错结构、具有降级功能的三模容余结构的体系结构、算法原理、关键技术等内容进行了研究。综合使用多种检测机制确保可靠锁定故障机,基于故障机无法修复时再逐步降级使用的策略,以正常工作的当班机为基础,通过故障机在每个流程的开始读取刷新后的当班机指针和重要状态参数并在流程的结束向当班机发送同步请求的方式,提出了一种具备重构能力的三模冗余器载计算机设计方案,设计了三模冗余重构流程,使故障机具备自修复的能力。实践表明,该重构方法能有效地提高器载计算机系统的可靠性,对高可靠器载计算机设计与实现具有较好的工程参考意义。     

Dynamic quality of transmission optimization and global impairments control in reconfigurable transparent WDM networks:schemes and demonstrations

<正>Two novel dynamical quality of transmission(QoT) optimization schemes with explicit optimization targets and accurate end-to-end QoT estimation are proposed for reconfigurable transparent wavelength-division multiplexing(WDM) networks.Numerical simulations show that the scheme of quality(Q) best has the best Q factor improvement with large attenuation adjustment.The scheme of Q allowable can achieve minimized number of tuning sites and attenuation adjustment and also improve the Q factor of light path to the required value.In addition,the idea of dynamic QoT optimization and global impairment control has been experimentally demonstrated on a simple mesh network by the cooperation of a control plane and tunable devices.     

Semi-Quantum Key Distribution Protocols with GHZ States

With the development of information security, quantum key distribution (QKD) has attracted much attention. Because of the lower requirement on quantum capability, more attention is paid to semi-quantum key distribution (SQKD). Two semi-quantum key distribution protocols based on GHZ states are proposed. The first protocol can achieve quantum key distribution between one classical party and one quantum party by cooperating with a third party with a strong quantum capability. Under the same conditions, the second one can achieve quantum key distribution between two classical parties. And the proposed semi-quantum key distribution protocols are free from some common attacks. It is significant for communication party without enough quantum devices to achieve quantum communication.     

Failure location mechanism in long-reach PON based on OCDR

An efficient and unambiguous failure monitoring and protection mechanism is proposed in long-reach passive optical network (LR-PON). Optical code domain reflectometer by optical coding scheme is utilized. Improved optical encoders are placed centrally in optical distribution network and at both sides of each remote node to monitor all links and nodes in the network, which can make much simpler installation and smaller management costs. A reliable and robust protection system is designed and it can protect LR-PON from multiple fault cases. The network can achieve monitoring and protection process by network management system centrally. After locating fault, the system can also monitor the network continuously. The performance analysis of the monitoring system: signal-to-noise-plus-interference ratio, signal-to-interference-ratio and signal-to-noise-ratio are studied. Furthermore, the performance of data signals for protection system is investigated by bit error rate. The results obtained prove the feasibility and efficiency of the proposed network, and it can support high network capacity.     

不同耦合下混沌神经元网络的同步

采用Hindmarsh-Rose神经元动力学模型, 对二维点阵上的神经元网络的同步进行了研究. 为了解不同耦合对网络同步的影响, 提出了一般反馈耦合、分层反馈耦合和分层局域平均场反馈耦合三种方案.研究表明:在耦合强度较小的近邻耦合下, 一般反馈耦合不能使网络达到完全同步, 而分层反馈耦合和分层局域平均场反馈耦合可以使网络出现局部同步和全局同步. 不同形式的耦合会导致网络出现不同的斑图, 随着耦合强度的增大, 网络从不同步到同步的过程也不相同, 一般反馈耦合和分层反馈耦合网络是突然出现全局同步, 同步之前网络出现非周期性的相干斑图; 对于分层局域平均场反馈耦合网络, 同层神经元之间先出现从簇放电同步到同步的转变, 形成靶波, 然后同步区由中心向外逐渐扩大, 最终达到网络的全局同步. 这些结果表明, 只有适当的耦合才能实现信号的无损耗的传递. 此外我们发现分层局域平均场反馈耦合可以促进网络的同步.     

基于去模糊空间变换RCNN的毫米波图像目标检测（英文）

提出一种包含去模糊的空间变换区域卷积神经网络的目标检测算法.首先,基于主动毫米波圆柱扫描成像原理对人体进行三维成像(频率24~30 GHz),建立毫米波图像数据集.然后,估计毫米波图像的模糊核,通过卷积去噪网络获得图像先验知识,将其集成到半二次分裂的优化方法中,以实现非盲目去模糊.最后,由定位网络、网格生成器和采样网络三部分组成空间变换网络,将它融入到特征提取网络中,在去模糊后实现目标检测.通过该非盲目去模糊算法得到的图像的峰值信噪比可达27.49 dB,目标检测算法的平均精度可达80.9%.实验结果表明,与现有的先进方法相比,该方法可以有效地提高图像质量和检测精度,为毫米波图像中隐藏危险品的目标检测提供了新的技术支持.     

Si/Ge/Si异质横向SPiN二极管固态等离子体解析模型

采用横向表面PiN(SPiN)二极管构造的硅基可重构天线具有众多优于传统天线的独特优势, 是实现天线小型化和提升雷达与微波通信系统性能的有效技术途径. 本文提出一种Si/Ge/Si异质横向SPiN二极管, 并基于双极扩散模型与Fletcher型边界条件, 在大注入条件下建立了二极管结电压、电流密度与本征区固态等离子体浓度分布解析模型, 并数值模拟分析了本征区长度、P⁺与N⁺区掺杂浓度、外加电压对所建模型的影响. 结果表明, 固态等离子体浓度随本征区长度的增加下降, 随外加电压的增加而指数上升, 随P⁺与N⁺区掺杂浓度的提高而上升, 电流密度随外加电压的增加而指数上升. 同等条件下, 异质SPiN二极管的固态等离子体浓度相比同质二极管提高近7倍以上. 本文所建模型为硅基可重构天线的设计与应用提供有效的参考.     

Synchronizability of chaotic logistic maps in delayed complex networks

We study a network of coupled logistic maps whose interactions occur with a certain distribution of delay times. The local dynamics is chaotic in the absence of coupling and thus the network is a paradigm of a complex system. There are two regimes of synchronization, depending on the distribution of delays: when the delays are sufficiently heterogeneous the network synchronizes on a steady-state (that is unstable for the uncoupled maps); when the delays are homogeneous, it synchronizes in a time-dependent state (that is either periodic or chaotic). Using two global indicators we quantify the synchronizability on the two regimes, focusing on the roles of the network connectivity and the topology. The connectivity is measured in terms of the average number of links per node, and we consider various topologies (scale-free, small-world, star, and nearest-neighbor with and without a central hub). With weak connectivity and weak coupling strength, the network displays an irregular oscillatory dynamics that is largely independent of the topology and of the delay distribution. With heterogeneous delays, we find a threshold connectivity level below which the network does not synchronize, regardless of the network size. This minimum average number of neighbors seems to be independent of the delay distribution. We also analyze the effect of self-feedback loops and find that they have an impact on the synchronizability of small networks with large coupling strengths. The influence of feedback, enhancing or degrading synchronization, depends on the topology and on the distribution of delays.     

带有层级结构的复杂网络级联失效模型

针对现实世界的网络中普遍存在的层级结构建立一个级联失效模型, 该模型可用于优化金融、物流网络设计. 选择的层级网络模型具有树形骨架和异质的隐含连接, 并且骨架中每层节点拥有的分枝数服从正态分布. 级联失效模型中对底层节点的打击在不完全信息条件下进行, 也即假设打击者无法观察到隐含连接. 失效节点的负载重分配考虑了层级异质性, 它可以选择倾向于向同级或高层级完好节点分配额外负载. 仿真实验表明, 层级网络的拓扑结构随连接参数变化逐渐从小世界网络过渡到随机网络. 网络级联失效规模随隐含连接比例呈现出先增加后降低的规律. 负载重分配越倾向于高层级节点, 网络的抗毁损性越高. 同时, 由于连接参数会改变隐含连接在不同层级之间的分布, 进而对网络的抗毁损性产生显著影响, 为了提高网络抗毁损能力, 设计网络、制定管理控制策略时应合理设定连接参数. 关键词： 复杂网络 级联失效 层级结构     

Analysis of queuing delay in optical space network on LEO satellite constellations

Low earth orbit (LEO) satellite constellations using laser inter-satellite links (ISLs) are recognized as a promising technology to provide global broadband network services. In this paper, the queuing delay model of an optical space network built on LEO satellite constellations is established. It is assumed that the optical space network employs wavelength division multiplexing ISLs with wavelength routing technology to communication satellites and makes routing decisions. With consideration of the network task characterizations such as distribution of task arrival time and task holding duration, simulation experiment results are analyzed and the expression of optical space network queuing delay is given. Both theoretical analysis and simulation results show that features of queuing delay vary with distribution characterizations of the network tasks. It is hoped that the study can be helpful to evaluate the design of constellation networking.     

智能检索引擎中的网络数据挖掘技术优化研究

随着计算机网络技术的不断发展,对于Web Service检索技术的要求也越来越大。并且现在网络环境当中数据信息流量十分庞大,对于信息可以做到深入搜索,实现全方位信息查询是非常有必要的。为此,利用网络数据挖掘技术在智能检索引擎中的应用,以文本描述为信息作为本文的研究对象,为用户提供运用查询要求实现概念检索功能。其中强调在智能搜索引擎当中的网络数据挖掘技术进行优化研究,从结构设计以及算法分析上总结出当前网络数据挖掘应用智能检索的可能性。最终设计出一种利用数据挖掘技术的智能检索模型,实现在众多网络数据中可以准确快速的进行详细的信息检索功能。     

基于扩展DALI总线的智能照明系统设计

针对大型商业照明场合存在的如组网不便、照明效果单一,能源利用率底的问题,设计了一套基于扩展DALI总线的商业智能照明系统,以实现系统的大面积组网和集中控制,获得丰富的照明效果,实现系统的绿色环保运行。测试系统搭建完成后,实现了管理人员对系统的集中管理和远程监控;系统可按照工作日程表、时间表自动运行;具有分区、分组、单灯、场景等多种控制方式,控制灵活,能达到较好的照明效果和节能要求,可满足多种商业照明需求。     

Spatial light modulator as a reconfigurable intracavity dispersive element for tunable lasers

An improved approach for narrow-band wavelength selection in tunable lasers is described. To provide the tunability, a reconfigurable diffractive optical element (DOE) based on a programmable spatial light modulator (PSLM) is applied. With a proper choice of the phase transfer function of the PSLM, the device can be used as a dispersive intra-cavity component for precise tuning within the lasing spectral band of a solid-state dye laser. The suggested design allows avoiding the mechanical movement of any cavity components. The tunability performance and simulation are demonstrated using the Fourier optics method.