无线传感器网络流量的冗余抑制机制研究

冗余抑制是一种通过在接收节点缓存频繁传输的内容以避免多次发送重复数据的网络流量抑制技术.现有的解决方式需要有大量的内存,用于分析当前冗余流量并维持缓存.由于硬件的限制,无线传感器节点在同一时刻不能够提供相应的资源;协议和通信模式的多样性还使得通信中冗余发生的频率及其所占比例难以预测.因此,给出了一种改进的冗余抑制协议,通过概率流量分析以确定和缓存那些造成最多流量储存的冗余传输子集,实现性能表现接近于建立在全面分析和无约束缓存基础上的冗余抑制解决方案.     

基于混沌映射的伪随机序列发生器

提出了一种基于线性分段混沌映射(PWLCM)的收缩式伪随机序列发生器.针对分段线性混沌映射“逐段线性”的缺点,提出一种新的混沌轨迹比特位提取算法.该算法使用具有最长周期的线性移位寄存器(m-LFSR)所产生的序列来控制混沌轨道比特位的提取,从而有效避免混沌轨道泄露造成的安全性问题.分析表明,该发生器具有良好的密码学特性.     

自组网环境下基于组合公钥的分布式密钥管理

结合组合公钥密码体制和秘密共享思想,针对移动自组网环境,提出了一种分布式密钥管理方案.从系统初始化、管理平台构建、节点公私钥生成、私钥矩阵份额更新等4个方面进行了详细描述,并给出了具体实施方法.分析表明,该方案具有安全性高、扩展性强、计算量小、适用性好的特点,特别适合移动自组网环境.     

Control allocation for a V/STOL aircraft based on robust fuzzy control

This study addresses the design of an output-feedback H-infinity and fuzzy mixed controller for an advanced vertical and/or short take-off and landing aircraft that exhibits satisfactory global stability criteria. A fuzzy logic based optimization approach is employed to solve autonomously the constrained control allocation problem by suitably adjusting the components of the output vector and finding a proper vector in the attainable moment set. Simulations show that the designed fuzzy controller is better s...     

Fast feature-based mode decision for 4×4 intra prediction in H.264/AVC

Intra coding in H.264/AVC can significantly improve the compression efficiency at the cost of high computational complexity due to the use of the rate-distortion optimization technique.To reduce the complexity of intra prediction,we propose a feature-based mode decision algorithm for 4×4 intra prediction.This algorithm is motivated by the fact that a good prediction mode usually has a small residue block,which is the difference between the original block and predicted block.The sum of the absolute transformed coefficients and deviation information of residue block are used to measure the distortion of prediction mode and the smoothness of residue block,respectively.According to the ranking of these two features of all possible modes,and together with the most probable mode,small numbers of candidate modes can be determined.Moreover,the candidate modes are further reduced to only one by using two early termination rules based on the correlation of rank and most probable mode.Simulation results demonstrate that the proposed mode decision method reduces about 60% of total encoding time of intra coding with negligible loss of coding performance.     

组态监控PLC控制的电梯系统

利用组态王软件开发电梯远程监视系统,通过电梯远程监测装置实时监控电梯运行状态,运用PLC技术控制8层观光电梯系统,完成了电梯的运行、电梯门的开合、轿厢内外呼叫应答等功能,并结合变频器,完成了电梯的变频调速。     

渣处理自动控制故障分析与措施

介绍高炉INBA法渣处理工作原理和转鼓自动控制故障和自动控制故障的方法,以及INBA自动控制改造措施与故障的解决方法。     

An efficient and DoS-resistant user authentication scheme for two-tiered wireless sensor networks

Wireless sensor networks (WSNs) are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and denial-of-service (DoS)-resistant user authentication scheme for two-tiered WSNs.The proposed approach reduces the computational load,since it performs only simple operations,such as exclusive-OR and a one-way hash function.This feature is more suitable for the resource-limited sensor nodes and mobile devices.And it is unnecessary for master nodes to forward login request messages to the base station,or maintain a long user list.In addition,pseudonym identity is introduced to preserve user anonymity.Through clever design,our proposed scheme can prevent smart card breaches.Finally,security and performance analysis demonstrates the effectiveness and robustness of the proposed scheme.     

基于CORDIC算法的高速正余弦函数实现架构

坐标旋转数字计算机算法（Coordinates Rotation Digital Computer （CORDIC） Algorithm）,其硬件结构实现简单,可以在硬件系统中实现包括乘、除、各种三角函数、自然对数和平方根在内的初等函数;针对图像处理对计算速度要求高的特点,本文采用了多级流水线的实现架构,可以明显提高CORDIC电路的工作频率;为了进一步地减少各级流水线的计算时延,电路中采用了运算速度较快的BKA加法器。基于Altera公司的FPGA（EP2C5F256C7）芯片的CORDIC算法架构综合,使其能够工作在188．38MHz的最高时钟频率。仿真结果表明本文提出的CORDIC架构能高速正确地实现CORDIC算法。     

Some improved results on communication between information systems

To study the communication between information systems, Wang et al. [C. Wang, C. Wu, D. Chen, Q. Hu, C. Wu, Communicating between information systems, Information Sciences 178 (2008) 3228-3239] proposed two concepts of type-1 and type-2 consistent functions. Some properties of such functions and induced relation mappings have been investigated there. In this paper, we provide an improvement of the aforementioned work by disclosing the symmetric relationship between type-1 and type-2 consistent functions. We present more properties of consistent functions and induced relation mappings and improve upon several deficient assertions in the original work. In particular, we unify and extend type-1 and type-2 consistent functions into the so-called neighborhood-consistent functions. This provides a convenient means for studying the communication between information systems based on various neighborhoods.