Variation-aware approaches with power improvement in digital circuits

In submicron technology, during the fabrication process factors like lithography and lens defect can change some of the physical parameters of transistors and interconnects. This change can modify the transistor electrical characteristics such as current, threshold voltage and gate capacitance, and thus it causes variation in power, delay and performance of the circuit. Process variation has become one of designer׳s challenges to the point that in below 45 nm technology it is considered as the most important issue in reliability. Power consumption and transistors variation are limiting factors to physical scalability. In this paper, we propose two approaches to reduce D2D and WID variations effects on digital CMOS circuits, at design time. The first approach concerns a variation-aware algorithm capable of extracting optimal design parameters to decrease variation and power. The second approach, using transistor stacking will help further reduce variation and power. Applying the algorithm on a digital design and according to parameters behavior in the presence of variation, we extract for each parameter value that will lead to power and variation reduction. On the other hand, with the stacking approach only basic gates are considered and subsequently gate configurations that reduce power and variation are proposed. The proposed approaches could be used identically for synchronous and asynchronous circuits. To prove this claim, we apply our approaches to a network-on-chip asynchronous router and a circuit from the ISCAS85 benchmark. All simulations are done in 32 nm technology using the HSPICE tool. The proposed algorithm similar to Monte Carlo simulation achieves the same results; however with lower execution time. The application of stacking approach to both asynchronous router and ISCAS85 circuit reduces variation effects up to 40.9% and 13.35%, respectively.     

基于不可靠通信链路的数据共享模块

随着企业规模的逐步扩大和计算机网络与企业信息技术的飞速发展，大中型企业陆续建立了很多业务系统，对各个系统之间数据同步的安全性提出了更高的需求。针对此需求，基于RabbitMQ消息队列中间件，本文设计并实现基于不可靠通信链路的数据共享模块，解决在企业内部两级数据中心之间的双向数据同步问题，并通过RabbitMQ的消息确认机制和持久化机制，保证数据的安全送达、无丢失。经过实践证明，该数据共享模块功能稳定，可提高两级数据中心的数据传输效率并保证其安全性。     

车联网环境下基于节点认知交互的路由算法

针对车联网（IoV）环境下消息传输效率低下、网络资源开销较大等诸多问题，提出一种适用于城市交通场景下基于车辆节点认知交互的路由算法。首先，依据信任理论提出节点认知交互度的概念，并在此基础上对车联网中的车辆节点进行分类，赋予它们不同的认知交互度初值；同时还引入车辆节点交互时间、交互频率、车辆节点物理间隔距离、间隔跳数以及消息生存时间等影响因子，进而构建了车辆节点认知交互评估模型。基于该模型计算并更新节点的认知交互度，并通过比较对应车辆节点间的认知交互度值来选取认知交互度相对较高的邻居节点作为中继节点进行消息转发。仿真实验结果表明，与Epidemic和Prophet路由算法相比，所提路由算法有效提高了消息投递率并降低了消息投递时延，同时显著降低了网络资源的开销，有助于提升车联网环境的消息传输质量。     

基于哈希链的软件定义网络路径安全

针对软件定义网络中，控制器无法保证下发的网络策略能够在转发设备上得到正确执行的安全问题，提出一种新的转发路径监控安全方案。首先以控制器的全局视图能力为基础，设计了基于OpenFlow协议的路径凭据交互处理机制；然后采用哈希链和消息验证码作为生成和处理转发路径凭据信息的关键技术；最后在此基础上，对Ryu控制器和Open vSwitch开源交换机进行深度优化，添加相应处理流程，建立轻量级的路径安全机制。测试结果表明，该机制能够有效保证数据转发路径安全，吞吐量消耗比SDN数据层可信转发方案（SDNsec）降低20%以上，更适用于路径复杂的网络环境，但时延和CPU使用率的浮动超过15%，有待进一步优化。     

Transmission of medical messages of patient using control signal of cellular network

The healthcare system needs to track and monitor patients’ status and information. One of the most important requirements is that the patient is able to access the service anywhere at any time. Systems are being developed using the Internet to monitor patients’ status, and in some areas, especially rural areas and motorways, the Internet may not be available, even though the mobile network is available. In some cases, the network might be overloaded, so the patient information cannot be delivered to the hospital or medical centre. We propose a new method that uses the spare extension of the random access channel (RACH), which is carried by physical random access channel (PRACH) to send the patient information to the medical centre. We present the mathematical model of the channel and compare the results with another system from 3GPP to evaluate the results. The results show that the proposed method needs less time to transmit the patient’s information.     

The influence of textese on adolescents’ perceptions of text message writers

Text messages are characterised by a casual language style, ‘textese’ (e.g., c u on thurs). This study investigated adolescents’ perceptions of the use of different levels of textese in digital messages which varied in their intended recipient (friend, teacher). Grade 8 students in Australia (N = 90, aged 13–14 years) each read six text messages purportedly written by a fellow student, and rated the extent to which they agreed (on a 7-point Likert scale) that the message writer was intelligent, paid attention to detail, used an appropriate writing style, and was friendly. Overall, participants rated message senders most favourably on all measures when they used no textese, and least favourably when they used high levels of textese. This pattern was even stronger when messages were addressed to teachers rather than same-aged friends. The findings suggest that adolescents are sensitive to both writing style and recipient when considering digital messages.     

基于能量平衡的电能路由器综合控制技术

电能路由器由多级电力电子变换单元组合而成,利用各级单元之间的能量传递关系实施综合控制可以提高电能路由器内部直流母线电压的瞬态性能,进而提高电能路由器的瞬态性能。本文首先建立电能路由器的能量模型,然后建立两条不同时间尺度的能量支路,根据其中的能量平衡关系分别设计了控制两级母线电压的能量平衡控制器,同时根据拓扑中各个级联模块之间的能量关系设计了用于级联模块的均压控制器。之后,对于实际系统中无源器件的参数差异对控制模型的影响进行分析,最后给出了基于能量平衡关系的电能路由器的并网运行综合控制策略。仿真结果证明了所提能量平衡控制方法的有效性,并分析了两级母线电容值变化分别对各自母线电压瞬态值的影响,说明采用能量平衡控制可以减少母线电容的设计余量。实验结果验证了理论分析和仿真结果的正确性。     

西气东输江都-如东线网络架构的优化

针对西气东输江都-如东线频繁出现网络故障的情况,基于江都-如东线现有网络架构,分析了网络系统存在的不足,对网络架构进行了优化,重新划分了局域网,处理了网络环网,禁用了路由器的多余广播,进行了风暴控制,优化了ESD系统参数,提出了在江都-如东线进行网络架构优化的方案。通过对思科交换机、思科路由器、SIXNET交换机和ESD系统的配置进行修改,以及为期1年的试运行,实现了网络故障零发生的目标,提高了网络通讯的质量,保证了系统的可靠性和安全性。     

能源互联网路由策略研究

能源互联网将可再生能源技术与互联网技术相结合,实现分布式可再生能源的大规模利用与分享。针对在以"能源路由器"为基础、以"微电网"为结构单元的能源互联网中,存在大规模、频繁的能量与信息转移传输现象,即能量信息流的"路由"问题,基于能源互联网理想路由模型,利用复杂网络理论,提出3种路由策略,解决3种考虑不同因素下的能量信息流路由问题。针对"能量传输拥塞"问题,提出基于边权的路由策略;针对"能量负载均衡"问题,提出基于网络邻节点负载的路由策略;在同时考虑"能量传输拥塞"和"能量负载均衡"影响下,提出联合路由策略,并通过仿真实验证明了该策略的可行性与有效性。     

基于点对点通信的分布式实时控制技术

对智能电网、清洁能源系统中存在的多种分布式系统进行了共性需求分析,针对分布式系统的工程技术特点,提出了一种基于点对点通信的新型分布式实时控制技术,通过点对点报文通信的方式实现了模拟量及开关量采集模块、出口控制模块和主处理器模块等环节的实时控制,满足了分布式系统对分散单元协同控制的工程应用需求。文中基于两种成熟的工业通信协议,针对两类分布式控制装置采用现场可编程逻辑门阵列(FPGA)对此技术进行了实现,并对装置进行了详细的测试与分析。两类典型装置已经在工程现场得到了试运行与推广,取得了良好的工程应用效果。