ZigBee技术及测试认证综述

介绍了IEEE 802.15.4标准的一致性测试的流程,并给出了测试实例.同时,阐述了ZigBee协议栈的构成及ZigBee产品的一致性测试和互操作性测试.     

水声传感网MAC协议的研究进展

水声传感网因其广阔的应用领域和巨大的应用潜力,近年来已成为通信领域的研究新热点,MAC协议是水声传感网的重要组成部分.概述水声传感网MAC协议的研究现状,指出水声传感网的MAC协议大体可分为基于非竞争的MAC协议和基于竞争的MAC协议,并对不同类别协议的优缺点进行对比分析.针对现有各种协议在吞吐量、开销、信道利用率以及网络的扩展性等方面均存在优势和不足等,从如何更好地克服水声通信中的传播时延长、可用带宽有限、能量消耗大和移动性大等方面,提出更合理更实用的水声通信MAC协议将是该领域未来的重点研究方向.     

农村广播电视台如何架构媒体资产管理网络

为了使城乡统筹发展数字广播电视,必须架构适应农村广播电视台需求的媒体资产管理网络系统,以实现数字节目的制作、存储、资源管理与播出一体化,采用消息＋WebService实现综合信息管理系统,进行无缝连接,可充分利用媒体资产,使节目的生产与资源再利用的效益达到最大化。     

Skype协议分析及流量识别

近几年来,P2P网络技术发展迅速,Skype是创建Kazaa的组织开发的一个基于P2P的VoIP客户端,用户可以用Skype通过互联网进行语音通话.本文通过抓取Skype的流量数据进行协议分析,主要关注PC2PC的登录/注销,文字通讯,语音通信,文件传输及PC2Phone等过程,进而总结协议特征,提出了一种基于协议分析的Skype流量识别方法,结果显示识别率达到95％以上.     

Eco-friendly synthesis of guanidinyltetrazole compounds and 5-substituted 1H-tetrazoles in water under microwave irradiation

We have developed simple, short time, cost effective, purification of products by non-chromatographic methods and environmentally benign protocol for the synthesis of guanidinyltetrazoles and 5-substituted 1H-tetrazoles derivatives via [2,3]cyclo-addition reaction of nitriles and azide derivatives in water under microwave irradiation. All the synthesized products are screened for their in vitro antimicrobial activity. The synthesized compounds were obtained in excellent yield (85–98%).     

General probabilistic chain teleportation

We have investigated different strategies for chain teleportation of a d-level quantum state (qudit-state) with the non-maximally entangled channels. The total success probabilities of chain teleportation protocols, the separate chain teleportation protocol (SCTP) and the global chain teleportation protocol (GCTP) are calculated. In the SCTP the errors are corrected between every step while in the GCTP the errors are corrected only at the end. The result shows that the GCTP is more efficient than the SCTP. Nevertheless, the error-correction of the GCTP will become more complicated with the increase of the node number. For keeping away from this inconvenience of the GCTP, we have presented an eclectic strategy, the piecewise chain teleportation protocol (PCTP) to balance the efficiency and maneuverability of chain teleportation.     

RVIP: an indistinguishable approach to scalable network simulation at real time

In the hybrid simulation research, we investigate a new approach to build software virtual networks (SVNs) that are indistinguishable from their equivalent real live networks (LNs). We define the concept of ‘Network's Interactive Turing Test' based on the similar concept used in the artificial intelligence areas. Our goal is to actualize the interactive and indistinguishable real–virtual interface pair (RVIP) for large‐scale computer network simulations. By RVIP's support, a single SVN is indistinguishable from its equivalent LN. In the entire hybrid system, multiple LNs and multiple SVNs are connected using many RVIPs in an arbitrary topology and at real time. To actualize RVIP, the following necessary conditions must be satisfied: (i) the performance of the underlying simulation platform must be faster than real time; (ii) all needed changes incurred by introducing any SVN into an LN scenario are put on the simulation's side. To interact with an SVN, RVIP requires that no change is made on any live node; (iii) an SVN does not exchange simulation events with LNs, that is, only standard IP protocol interactions between SVN and LN are allowed. (iv) Any LN can be dynamically plugged into the hybrid scenario at real time, just like being plugged into an equivalent purely LN. Compared with existing hybrid simulation efforts on NS‐3, QualNet's EXata and OPNET's system‐in‐the‐loop, in this paper, we use the actual RVIP implementation to show that RVIP is a better candidate to pass the Network's Interactive Turing Test owing to the following two advantages: (i) an interactive network tester can easily distinguish the existing hybrid networks from the LNs by using a live topology that cannot be simulated, for example, by including the entire live Internet. But RVIP is not vulnerable to such tests. RVIP can support hybrid scenarios with multiple SVNs and multiple LNs connected by an arbitrary network topology, and with the LNs on and off at anytime. (ii) Performance‐wise, our studies show that RVIP provides more efficient support in terms of common metrics such as larger throughput limit and smaller extra latency; thus, the simulated SVNs are more indistinguishable from their live counterparts. Copyright © 2014 John Wiley & Sons, Ltd.     

Liquid chromatographic behavior of two alanine‐substituted calix[4]arene‐bonded silica gel stationary phases

Two new kinds of alanine‐substituted calix[4]arene stationary phases of 5,11,17,23‐p‐tert‐butyl‐25,27‐bis(l ‐alanine‐methylester‐N‐carbonyl‐methoxy)‐26,28‐dihyroxycalix[4]arene‐bonded silica gel stationary phase (BABS4) and 5, 11, 17, 23‐p‐tert‐butyl‐25,26,27,28‐tetra(l ‐alanine‐methylester‐N‐carbonyl‐methoxy)‐calix[4]arene‐bonded silica gel stationary phase (TABS4) were prepared and characterized in the present study. They were compared with each other and investigated in terms of their chromatographic performance by using polycyclic aromatic hydrocarbons, disubstituted benzene isomers, and mono‐substituted benzenes as solute probes. The results indicated that both BABS4 and TABS4 exhibited multiple interactions with analytes. In addition, the commonly used Tanaka characterization protocol for the evaluation of commercially available stationary phases was applied to evaluate the properties of these two new functionalized calixarene stationary phases. The Tanaka test results were compared with Zorbax Eclipse XDB C₁₈ and Kromasil phenyl columns, respectively. BABS4 has stronger hydrogen‐bonding capacity and ion‐exchange capacity than TABS4, and features weaker hydrophobicity and hydrophobic selectivity. Both of them behave similarly in stereoselectivity. Both BABS4 and TABS4 are weaker than C₁₈ and phenyl stationary phases in hydrophobicity and hydrophobic selectivity.     

基于802.11协议的无线传感器数据流优先级模型

本文利用数学分析方法做了验证,结果表明,该机制对于高优先级数据数据优先传送的作用是非常明显的,在传输过程,数据流分组丢失的情况也得到了有效遏制。本文还对该机制的能耗情况进行了分析,结果表明,高优先级的能耗水平低于低优先级,并且这种趋势随着节点数的增加而更加明显。因此,本文所提出的提高高优先级传输效率的机制,更适用于节点数比较高的网络中。