构建安全的虚拟网

为建设安全高效的企业、虚拟网 .本文综合分析虚拟专用网VPN的隧道协议、用户认证及VPN与防火墙集成的安全问题     

安全协议分析的界——综合模型检查与Strand Spaces(英文)

Strand Spaces是一种用于分析安全协议的机器证明方法.简要介绍了 Strand Spaces的基本特点,分析了其优劣,提出了构造协议的理想子环的算法,并以此来约束协议入侵者的能力和协议并行运行的次数.将模型检查与 Strand Spaces结合在一起,提出了一种综合分析方法来验证协议的安全特性,该方法可充分发挥模型检查与 Strand Spaces二者的优势.     

多媒体通信协议分析

随着VoIP和视频通信的发展,H.323和SIP作为IP多媒体通信领域中被广泛采纳的两种信令控制协议,受到业界的普遍重视.对这两种关键协议分析比较,认为将二者互通协调,H.323和SIP在各自的领域内必将会有更大的发展前景.     

基于Unix的IPv6 RIPng的实验研究

文章介绍了基于下一代网络IPv6下的RIPng路由协议的工作原理,进行了在Unix下实现RIP协议的配置、安装及其连通性的实验,并对实验数据进行了分析。RIPng路由协议因其简单易用也成为当前重点研究的路由技术。     

无线传感器网络跨层路由协议研究

近年来,伴随着无线传感器网络在军事、环境监测等领域所取得的成就,无线传感器网络已经成为科技领域研究的重要课题之一.由于无线传感器网络一些新的特点,传统的路由协议并不适用于无线传感器网络中.针对这些新特点,许多基于跨层设计的路由协议相继被提出.按照跨层设计的思想对无线传感器网络的路由协议进行划分,并进行了比较与分析.在对现有协议研究分析的基础上,进一步指出了无线传感器网络中跨层路由设计的一些新思路.     

基于OpenPLC的医疗仪器通信协议转换平台设计

医疗仪器信息集成已成为医疗卫生信息化不可或缺的一环。由于非影像类医疗仪器信息传输标准滞后,使这类医疗仪器信息集成发展较为缓慢。通过分析多种通信协议,利用图形化编程优势,基于OpenPLC设计实现了一种医疗仪器通信协议转换软件的组件化设计平台。使用模块拼接完成医疗仪器数据帧协议转换配置,在保证协议转换通用性、易用性的同时,降低了使用人员的技术门槛。     

基于RFID标签隐私查询策略

为了能有效保证射频识别(RFID)系统中用户的隐私和数据安全,运用分布式RFID询问应答认证协议,Elgamal密码系统、认证机制和可验证门限秘密共享等协议对标签数据认证查询.该策略不仅查询可靠,还具有保护被查询对象和查询结果隐私安全等特点.通过其安全性能分析和效率分析,说明了本协议具有高效的性能和良好的安全性、可靠性.     

异构系统开放封装的技术分析与实现框架

1　开放封装的意义现实系统环境是一个由众多分布、异构和自主的资源系统组成的开放环境 ,现实应用则要求对这些系统进行整合来向用户提供逻辑化甚至个性化的集成服务。为了形成有效的集成服务 ,我们可以要求新建设的资源系统采用标准的元数据格式、检索方式、检索记录调用机制、检索记录传输格式和传输协议 ,从而支持整合检索、开放链接和基于Web的集成使用[1] 。但对于已经存在的资源系统和第三方资源系统 (在中国科学院这些系统可能占多数 ) ,它们往往各自具有自己的数据结构、检索方式、检索与调用协议、数据记录传输格式等。我们不可…     

The classroom observation protocol for socioscientific issue-based instruction: development and implementation of a new research tool

Background: For the past decade, science educators have been exploring the use of Socio-scientific Issues (SSI) as contexts for science teaching and learning, and research indicates that doing so can support significant learning gains. However, research related to how teachers take up the practice of SSI-based instruction is far more limited, due in part to a lack of tools for use in this kind of research.

Purpose: The focus of this research is development and testing of a new classroom observation protocol specifically designed for SSI-based instructional contexts.

Design and methods: Development of this SSI-Observation Protocol (SSI-OP) took place in four distinct phases: review of existing protocols and SSI-based instruction frameworks, writing and revision of protocol items, initial testing of the draft protocol, and soliciting feedback from SSI experts.

Sample: Following the four stages of SSI-OP development, we progressed to a series of field tests. The field tests were conducted with three different samples. The first sample was an experienced (10 + years) high school biology teacher and one of her honors biology classes. The second sample consisted of seven Turkish Pre-service Science Teachers (PST) participating in a science methods course. The third sample included two Thai PST from a field experience course embedded within a teacher education program.

Results: The final version of the protocol addressed five dimensions of SSI-based instructional activities: focus of instruction, teaching moves, role of teacher, role of students, and classroom environment.

Conclusions: The SSI-OP could be used in a variety of ways for research including documentation of current practices, impacts of professional development and/or curricula on teaching practices, and changes in teaching over time. We offer the SSI-OP as a new tool with the potential to contribute to science teacher education and research that may advance the teaching and learning of science through SSI.     

TCP/IP协议与网络故障实战

TCP/IP协议是网络中计算机之间通信的“语言”,TCP/IP协议系统的层次结构和数据传输机制,使之成为Internet上最为实用的协议。在诊断网络故障中,清晰地把握此协议,可使网络故障的诊断与排除变得更加简单。