摘要：A novel Discrete Wavelet Transform (DWT) based Hidden Markov Module (HMM) for face recognition is presented in this letter. To improve the accuracy of HMM based face recognition algorithm, DWT is used to replace Discrete Cosine Transform (DCT) for observation sequence ex- traction. Extensive experiments are conducted on two public databases and the results show that the proposed method can improve the accuracy significantly, especially when the face database is large and only few training images are available.

摘要：化学取代是有效调节分子电导,产生多通道输运、量子干涉效应和其他机制的关键方法.但分子骨架和侧基之间存在复杂的相互作用,目前仍未被研究清楚.在本工作中,我们结合扫描隧道显微镜裂结实验技术和第一性原理计算方法,深入研究了具有不同σ和π侧基的分子电导.实验结果及理论分析表明,σ侧基的加入引起了分子前线轨道的对称性破缺并加剧了分子内散射,从而导致电导的降低.相反,π侧基引入了额外的电荷传输通道,实现了电荷传输的多通道效应,增加了分子的电导.这些发现为未来分子功能化和分子电子器件的设计提供了坚实的基础.

摘要：The recent decade has witnessed an upsurge in the demands of intelligent and simplified Internet of Things(IoT)networks that provide ultra-low-power communication for numerous miniaturized *** the research community has paid great attention to wireless protocol designs for these networks,researchers are handicapped by the lack of an energy-efficient software-defined radio(SDR)platform for fast implementation and experimental *** SDRs perform well in battery-equipped systems,but fail to support miniaturized IoT devices with stringent hardware and power *** paper takes the first step toward designing an ultra-low-power SDR that satisfies the ultra-low-power or even battery-free requirements of intelligent and simplified IoT *** achieve this goal,the core technique is the effective integration ofµW-level backscatter in our SDR to sidestep power-hungry active radio frequency *** carefully develop a novel circuit design for efficient energy harvesting and power control,and devise a competent solution for eliminating the harmonic and mirror frequencies caused by backscatter *** evaluate the proposed SDR using different modulation schemes,and it achieves a high data rate of 100 kb/s with power consumption less than 200µW in the active mode and as low as 10µW in the sleep *** also conduct a case study of railway inspection using our platform,achieving 1 kb/s battery-free data delivery to the monitoring unmanned aerial vehicle at a distance of 50 m in a real-world environment,and provide two case studies on smart factories and logistic distribution to explore the application of our platform.

摘要：There are a lot of security issues in block cipher *** analysis and enhanced design of a dynamic block cipher was ***,the safety of ciphertext was enhanced based on confusion substitution of S-box,thus disordering the internal structure of data blocks by four steps of matrix ***,the diffusivity of ciphertext was obtained by cyclic displacement of bytes using column ambiguity *** dynamic key was finally generated by using LFSR,which improved the stochastic characters of secret key in each of round of *** safety performance of proposed algorithm was analyzed by simulation *** results showed the proposed algorithm has a little effect on the speed of encryption and decryption while enhancing the ***,the proposed algorithm has highly scalability,the dimension of S-box and the number of register can be dynamically extended according to the security requirement.

摘要：Since most ad hoc mobile devices today operate on batteries,the power consumption becomes an important *** paper proposes a cross-layer design of energy-aware ad hoc on-demand distance vector(CEAODV) routing protocol which adopts cross-layer mechanism and energy-aware metric to improve AODV routing protocol to reduce the energy consumption and then prolong the life of the whole *** CEAODV,the link layer and the routing layer work together to choose the optimized transmission power for nodes and the route for *** link layer provides the energy consumption information for the routing layer and the routing layer chooses route accordingly and conversely controls the link layer to adjust the transmission *** simulation result shows that CEAODV can outperform AODV to save more *** can reduce the consumed energy by about 8%over traditional energy-aware *** the performance is better when the traffic load is higher in the network.

摘要：本文提出一种在特殊任务下基于Chebychev映射的移动机器人混沌全覆盖路径规划器的设计新策略。所设计的混沌路径规划器包含一个二维的Chebychev映射,该映射由两个一维的Chebychev映射构建而成。对规划器所产生的时间序列,进行反正弦变换,可以改善系统的混沌特性和均匀分布特性,从而提高机器人在完成特殊任务时的覆盖率和随机特性。通过仿射变换,Chebychev混沌系统映射到机器人工作空间的可行区域内,然后设计有障碍物环境下全覆盖路径规划的通用方法。仿真结果显示,所设计的混沌路径规划器在可行空间能够安全运行,不需要设计避障算法。所设计策略能够满足特殊任务下随机性、遍历性和高效率的需求。

摘要：Not So Cooperative Caching(NSCC) considers a network comprised of selfish nodes; each is with caching capability and an objective of reducing its own access cost by fetching data from its local cache or from neighboring caches. These nodes would cooperate in caching and share cached content if and only if they each benefit. The challenges are to determine what objects to cache at each node and to implement the system in the context of information Centric Networking(ICN). This work includes both a solution for the NSCC problem and a design and implementation of an NSCC system in Named Data Networking(NDN), a large effort that exemplifies ICN. Our design applies NDN synchronization protocol to facilitate the information exchange among nodes, adopts group key encryption to control data access within the NSCC group, and offers an error checker to detect error events in the system. Our approach is validated by deploying the system we developed on Planet Lab.

摘要：光场成像是计算摄像学领域一项新兴技术。基于对成像模型和光路的创新设计,光场相机不仅记录了三维物体的空间强度,而且捕获了物理世界中的角度信息。这为解决三维重建、显著区域检测、目标识别等计算机视觉问题提供了新途径。本文首先回顾了光场相机的三个关键问题,包括成像模型、标定理论以及重建方法。然后,系统介绍了光场成像技术在信息学、物理学、医学和生物学等领域的应用现状。最后,讨论了光场成像目前存在的问题,并展望了光场成像技术的应用前景。

摘要：Efficiency and scalability are still the bottleneck for secure multi-party computation geometry(SMCG).In this work a secure planar convex hull(SPCH) protocol for large-scaled point sets in semi-honest model has been proposed efficiendy to solve the above ***,a novel privacy-preserving point-inclusion(PPPI) protocol is designed based on the classic homomorphic encryption and secure cross product protocol,and it is demonstrated that the complexity of PPPI protocol is independent of the vertex size of the input convex *** then on the basis of the novel PPPI protocol,an effective SPCH protocol is *** shows that this SPCH protocol has a good performance for large-scaled point sets compared with previous ***,analysis finds that the complexity of our SPCH protocol relies on the size of the points on the outermost layer of the input point sets only.

摘要：Role based access control is one of the widely used access control *** are investigations in the literature that use knowledge representation mechanisms such as formal concept analysis(FCA),description logics,and Ontology for representing access control ***,while using FCA,investigations reported in the literature so far work on the logic that transforms the three dimensional access control matrix into dyadic formal *** transformation is mainly to derive the formal concepts,lattice structure and implications to represent role hierarchy and constraints of *** this work,we propose a methodology that models RBAC using triadic FCA without transforming the triadic access control matrix into dyadic formal *** discussion is on two lines of *** present how triadic FCA can provide a suitable representation of RBAC policy and we demonstrate how this representation follows role hierarchy and constraints of RBAC on sample healthcare network available in the literature.