基于时分多路接入自适应休眠的低功耗DOCSIS上行发射器

针对DOCSIS上行发射器的高功耗问题,通过建立DOCSIS上行信道多电缆调制解调器(CM) 突发传输和功耗模型,提出了一种基于时分多路接入(TDMA)方式接入自适应休眠的低功耗上行发射器的设计方法.典型网络环境下的实验结果表明,所提出方法能使DOCSIS上行发射器降低51.37%的功耗.该低功耗DOCSIS上行发射器已经成功应用于符合EuroDOCSIS1.1 规范的支持双向有线电视点播的CM SOC平台中,并表现出优良的低功耗性.     

一种无人直升机一站三机测控系统

为解决数据链一站控制三架无人直升机的问题，设计了一种基于动态调整发送数据时隙的时分多址数据回传方法。通过计算无人直升机相对于地面站的实时位置，对每架机的回传数据时隙和时机进行动态分配和通信延时补偿，从而有效利用数据信道。实验证明，该方案能完成对无人直升机的一站三机控制，并可扩展到其他类型无人机一站多机测控系统。     

基于离散傅立叶变换扩频的广义多载波系统收发机频域简化实现方法

针对基于离散傅立叶变换扩频的广义多载波(DFT-S-GMC)系统的收发机时域实现方法复杂度较高的问题,提出了一种频域等效收发机实现方法;利用滤波器组各子带频率响应能量比原型滤波器的时域冲击响应能量集中的特性,提出了一种基于该频域实现方法的收发机简化实现方法和结构.仿真和分析表明,在多径信道下,采用频域简化实现结构的收发机与现有基于时域实现结构的收发机的误码率(BER)性能几乎相同,但与现有时域实现方法相比,采用频域简化实现方法,DFT-S-GMC系统发射机的实现复杂度可显著降低.     

可逆变长编码的解码器设计及VLSI实现

变长编码(VLCs,Variable Length Codes)因其高效的数据压缩能力被广泛地应用在多媒体压缩领域,但VLCs的自身性质使它对信道错误的恢复能力很弱。随着在不可靠信道,如无线信道和网络上进行视频传送需求的增加,视频通讯的错误控制和错误恢复技术变得越来越重要。可逆变长编码(RVLCs,Reversible Variable Length Codes),当遇到传输错误时,充分利用了可用的数据,错误恢复能力强于VLCs。许多视频标准,如ITU H．263 ,ISO MPEG-4已经采用了RVLCs。本文详细描述了RVLCs解码器的解码算法和解码器的体系结构设计,给出了一个基于MPEG-4 ASP@L5的解码器VLSI实现。结果表明,该实现完全适用于MPEG-4实时编解码系统。     

基于小波分解的视频分级编码方法

提出了一种基于小波分解的视频分级编码方法,该方法主要是对视频对象实施小波分解,将其低频子带与高频子带分别作为基本层与增强层进行编码,以实现视频对象的空域分级、时域分级与混合级。同时,根据小波的方向性特点,采用了视觉模式图像编码方法,以提高编码效率。     

瞬时自相关信道化接收机频率测量研究

提出了一种新的信道化IFM接收机的实现方案,该方案基于多相滤波的信道化技术,利用瞬时自相关方法实现复信号的瞬时频率测量,不仅可以实现精确的大动态范围瞬时频率测量,而且具备多信号同时处理能力,仿真结果和性能分析验证了本方法的有效性.     

数据融合和数据挖掘技术在数字电影流动放映信息回传体系中的应用研究

随着数字电影流动放映业务的规模化发展，对放映数据和放映情况的监管需求越来越大。本文介绍了数据融合和数据挖掘技术的理论基础，分析了基于影片解码卡和GPRS／GPS模块两种回传技术的各自特点。从技术原理和实际应用数据的分析出发，提出并设计了一套以数据融合和数据挖掘为核心，以两种回传技术所采集的信息数据为基础，以准确、详尽、可追溯为目标的回传信息综合分析处理应用结构。     

基于影片解码卡的数字电影信息回传体系

本文提出了基于影片解码卡(智能卡)的数字电影信息回传体系,并着重从影片解码卡COS优化和回传安全机制设计两个方面对信息回传体系进行了阐述.影片解码卡COS优化技术为影片解码卡完整记录回传信息提供了足够的用户空间.回传安全机制可以抗重放、假冒服务器、伪造传输数据和篡改传输数据等攻击,消除了信息回传出错、回传信息被篡改、伪造、窃取等安全隐患.测试结果和实际运行情况表明,本文提出的数字电影信息回传体系的安全性能符合实际使用的要求.     

基于线性非冗余预编码的MIMO-OFDM系统信道估计算法

文章针对MIMO-OFDM系统中的信道估计关键技术提出了一种信道估算方法—基于线性非冗余预编码和二阶统计量的信道盲估计算法,该算法利用预编码信号的二阶统计特性消除了调制信号的信息,然后又利用STBC（Space-Time Block Coding空时分组编码）特殊的复正交特性对参考子载波信道矩阵进行变换,将求逆过程转换成简单的线性处理过程,从而实现了低复杂度的信道估计。另外,该算法通过选取合适长度的统计数据,能够较快收敛。     

利用子空间的投影和跟踪改进OFDM信道估计

OFDM系统的LS信道估计可看作真实信道频率响应的一个有噪观察值，因此可采用子空间投影方法对噪声进行压缩。分析了利用子空间投影方法改进LSOFDM信道估计性能的实质，给出了利用子空间投影改进OFDM信道估计的一般框架，在此基础上将子空间投影推广到非LS信道估计方法。当信号子空间随时间变化时，需要采用子空间跟踪技术保持对信号子空间的良好估计，因此提出了一种基于子空间跟踪的参数化信道估计方法，仿真表明这种方法在性能上优于非参数化时的相应方法。     

区域性海洋观测水声通信网数据链路层研究

简要介绍了水声通信网的研究现状以及常用的组网方式,比较了几种可实际应用的数据链路层协议,在此基础上提出了一种适用于区域性海洋观测的混合型网络协议,进行了仿真研究。该协议通过记录网络中数据包的发送频率来动态地调整所使用的MAC（Media Access Control）协议,当频率较高时选择查询方式的MAC协议,减少数据包的冲突;当频率较低时选择MACAW（Media Access with Collision Avoidance for Wireless）,避免查询信号带来的额外开销。仿真结果表明,对于区域性海洋观测,这种包产生速率低,但可能出现短时间通信量大的应用情况,该协议可以有效地降低每bit的能耗,适用于长时间海洋观测。     

一种新的用于3G互连的盲均衡改进算法TDE—CMA

DVB中广泛使用的CMA均衡算法一直深受伪收敛问题的困扰。从CMA算法的代价函数、迭代方程 及初始化系数等方面对伪收敛问题进行研究,在此基础上提出一种带时延估计的CMA改进算法。该算法通过引 入时延校正因子来调整主径的位置,从而避免了伪收敛现象。计算机仿真表明该方法大大提高了原算法的收敛 性,并且具有运算量小、易实现的优点,是一种实用性较强的改进算法,适用于高速的３G互连应用。     

An optically-based inverse method to measure in-plane permeability fields of fibrous reinforcements

Structural composite manufacturing relying on Liquid Composite Molding technologies is strongly affected by local variability of the fibrous reinforcement. Optical techniques using light transmission are used and allow field measurements of areal weight (and fibre volume fraction) of glass fibre reinforcement. The coupling of obtained areal weight mappings along with injection flow fronts is used to extract in-plane permeability fields. The current work presents results with a focus on glass random mats, but the method can be adapted to any glass fibrous medium. A study of convergence and error due to discretization is performed. Also the influence of the stacking of fibrous layers on the preform variability is analyzed. The major advantage of the proposed technique is a relatively fast acquisition of statistical data on reinforcement variability, which can be later utilized in stochastic based process simulations.     

Fault impact and fault tolerance in multiprocessor interconnection networks

Growing complexity of parallel machines coupled with increasing chip densities escalates the need for fault tolerance and recovery in these systems. In pursuit of the goal of fault-tolerant multiprocessors, many techniques have been proposed. Since methods for designing fault-tolerant processors and memories are relatively mature, the techniques considered in this paper focus on the interconnection network (ICN) linking the processors. The impact of faults on non-fault-tolerant ICNs is contrasted with that in fault-tolerant networks. Fault tolerance in ICNs is addressed at two levels, inter-node or switch level and system level. Inter-node or switch level pertains to data and control integrity and system level deals with maintaining network connectivity and adequate performance levels in the presence of faults. Fault-tolerant schemes at the switching element level warrant some form of concurrent error detection such as the use of codes usually combined with a full handshake protocol. Space–time trade-offs involved in the use of various codes and protocols are investigated. At the system level, several augmented multi-stage switching ICNs, tree and ring networks are studied. The combined provision for fault tolerance together with improved performance in the non-fault condition is emphasized. Finally, strategies for network reconfiguration and rerouting after system failure are presented.     

二维复合压电型表面波声子晶体带隙特性

设计了在镍圆柱体底部添加薄环氧树脂并沉积在铌酸锂基底的二维复合压电型声子晶体。通过有限元法计算了该结构的能带结构、分析了其带隙特性。计算结果显示:通过引入环氧树脂来减小散射体的有效弹性模量,从而降低了声表面波(SAW)完全带隙,同时打开了多条SAW方向带隙。计算了传输损失来验证带隙的存在性且讨论了其传输特性。利用布里渊区高对称点X处不同本征模态的位移场分析了带隙的形成机理。此外,还研究了共振体几何参数对SAW完全带隙、XM方向SAW带隙特性的影响,研究发现,随环氧树脂厚度的增加,在XM方向出现了一条宽为158 MHz的宽禁带。研究结果为设计基于声子晶体的电声设备提供了参考。     

A Novel Quantum Stegonagraphy Based on Brown States

In this paper, a novel quantum steganography protocol based on Brown entangled states is proposed. The new protocol adopts the CNOT operation to achieve the transmission of secret information by the best use of the characteristics of entangled states. Comparing with the previous quantum steganography algorithms, the new protocol focuses on its anti-noise capability for the phase-flip noise, which proved its good security resisting on quantum noise. Furthermore, the covert communication of secret information in the quantum secure direct communication channel would not affect the normal information transmission process due to the new protocol’s good imperceptibility. If the number of Brown states transmitted in carrier protocol is many enough, the imperceptibility of the secret channel can be further enhanced. In aspect of capacity, the new protocol can further expand its capacity by combining with other quantum steganography protocols. Due to that the proposed protocol does not require the participation of the classic channel when it implements the transmission of secret information, any additional information leakage will not be caused for the new algorithm with good security. The detailed theoretical analysis proves that the new protocol can own good performance on imperceptibility, capacity and security.     

Channel adaptive multiple I/O protocol for mixed wireless and wired channels

The presence and availability of several independent wired and wireless networks within a communication environment has led to the channel adaptive multiple I/O (CAMIO) protocol being developed as an appropriate and novel technique for data transmission. The proposed system utilises an intelligent multiplexing technique that enables the transmission/reception of multiple data sources via several wired/wireless networks simultaneously. Real-time configuration and adaptation capabilities when data sources/channels are dynamically added/deleted/modified are described. Data prioritisation methods, combined with traffic control and congestion-reactive techniques, are presented. Simulation results demonstrate that the use of the CAMIO protocol over multiple transmission/reception channels increases the overall data transmission rate, handles the delivery of time-sensitive packets and maintains the quality of service, especially in situations where one or more communication channels fail to operate.     

IoT-based networking for humanoid robots

Abstract

In this paper, a new network communication approach, named real-time network (RTNET), is designed and implemented for humanoid robots. The proposed five network objects – alarm, condition, message, mail, and file are used to represent the task and priority of the communication data. Compared to the existing protocols, the network scheduling mechanism of RTNET arranges, more efficiently, the priority and flow control of the five network communication objects to meet real-time requirements for the limited bandwidth of the local area network. RTNET can be further integrated with other protocols, such as EtherCAT or controller area networks (CAN Bus) for local control systems, e.g. robot arms, to improve the communication mechanism. The RTNET can also be used over Ethernet to connect each subsystem and to exchange information among those systems. Also, an Internet of things (IoT) network structure based on RTNET is proposed in this paper. The information of each subsystems is collected through RTNET and users can access all components in the IoT network. In this paper, the concept of RTNET is presented and RTNET has been implemented on a National Taiwan University (NTU) humanoid robot control system with CAN Bus.     

IP组播路由协议的研究与实现

概述了组播路由协议，分析了协议独立的组播路由－稀疏模式（PIM－SM）的缺陷，提出多个会聚点（RPs)的PIM－SM的改进机制，多个RPs机制有效地提高了原有单个RP的PIM－SM协议的健壮性，有利于实现负载均衡、分类业务及提高系统的容错性能，并讨论多个RPs机制的开销问题。分析了PIM－SM实现细节和组播技术的前景。