非理想CSI下全双工双向中继网络安全性能研究

针对目前物理层安全研究大多未考虑信道估计误差对安全性能的影响,研究基于非理想信道状态信息（Channel State Information,CSI）的全双工双向中继网络安全性能。假设系统中用户之间没有直连链路,且无法获取CSI;采用最优中继选择方案,选取最优中继将信号进行解码转发至目的端;根据最大最小原则推导出系统安全容量和保密中断概率（Secrecy Outage Probability,SOP）的表达式,进一步分析影响系统保密性能的主要因素,并对比全双工与半双工系统性能的差异。仿真结果表明,当中继节点处在用户间的中点位置时,系统保密性能最好;同时,减小信道估计误差、窃听链路的平均信噪比及剩余自干扰能够有效降低系统SOP,适当地增加中继数目可以获得更好的安全性能。     

Deriving Protocol Models from Imperfect Service Conversation Logs

Understanding the business (interaction) protocol supported by a service is very important for both clients and service providers: it allows developers to know how to write clients that interact with a service, and it allows development tools and runtime middleware to deliver functionality that simplifies the service development lifecycle. It also greatly facilitates the monitoring, visualization, and aggregation of interaction data. This paper presents an approach for discovering protocol definitions from real-world service interaction logs. It first describes the challenges in protocol discovery in such a context. Then, it presents a novel discovery algorithm, which is widely applicable, robust to different kinds of imperfections often present in realworld service logs, and able to derive protocols of small sizes, also thanks to heuristics. As finding the most precise and the smallest model is algorithmically not feasible from imperfect service logs, finally, the paper presents an approach to refine the discovered protocol via user interaction, to compensate for possible imprecision introduced in the discovered model. The approach has been implemented and experimental results show its viability on both synthetic and real-world datasets.     

Modbus与Profibus DP协议设备之间的通信方案

随着工业自动化技术的不断发展,近年来工业自动化设备间的通信方案也越来越多。笔者通过S7-300配置、现场设备配置、AB7000网关设置,实现Modbus网络和Profibus DP网络之间数据的异构通信。整个系统具有稳定性和实时性,满足工业生产的要求,可以在自动化工程中广泛推广。     

一种适合移动设备的数字图像签名方案

根据移动商务中计算能力不对等的特点,针对数字图像,提出了一种新的有效的数字签名方案。在不泄漏图像原始信息的情况下,将信息分块之后发送给TP(Third-party)进行签名计算,然后将中间结果发回移动设备进行组合。描述了该协议的运行过程,分析了其在运算速度方面的性能,证明了该协议对各种网络攻击和网络意外所具有的安全解决能力。理论证明该方法可以在一定程度上解决未来移动商务中计算能力不对等的问题,并且可以保证通信的安全性。     

一种基于口令的防窃取私钥保护协议①

现代密码体制中,加密算法是公开的。因此数据安全取决于用户私钥的保护。目前彩的最为广泛的私钥保存方案是使用用户密码将私钥加密后保存在用户设备上,但是这种记法不能够抵抗攻击者在获取用户设备后,对其使用离线字典攻击。根据对一种现有的能够防窃取的用户设备与服务器联合签名的(S-RSA)协议的分析,提出一种新的基于口令的私钥保护(SS-RSA)协议,该协议通过用户设备与服务器联合对文件进行解密。能够有效的保护用户私钥的安全,并解决了S－RSA协议不能够抵抗拒绝服务攻击和用户票据取消后,用户私钥无法恢复的缺点。     

数据通信设备中协议软件研发的经验与思考

该文从研发一个数据通信设备的角度,提出了数据通信设备中协议软件研发所要考虑的关键环节,并给出了一些实践经验的总结。     

一种基于口令的防窃取私钥保护协议①

现代密码体制中,加密算法是公开的。因此数据安全取决于用户私钥的保护。目前彩的最为广泛的私钥保存方案是使用用户密码将私钥加密后保存在用户设备上,但是这种记法不能够抵抗攻击者在获取用户设备后,对其使用离线字典攻击。根据对一种现有的能够防窃取的用户设备与服务器联合签名的（S-RSA）协议的分析,提出一种新的基于口令的私钥保护（SS—RSA）协议,该协议通过用户设备与服务器联合对文件进行解密。能够有效的保护用户私钥的安全,并解决了S—RSA协议不能够抵抗拒绝服务攻击和用户票据取消后。用户私钥无法恢复的缺点。     

基于移动设备的匿名可追踪版权保护协议

提出了基于移动设备的匿名可追踪的版权管理协议。首先,它使用不断变换的临时身份来代替用户的真实 身份,使其他人不可能跟踪到用户,它关注用户动态,具有匿名性;其次,使用一次口令申请一个水印的方法来抵杭假 冒攻击;再次,采用单向哈希函数的认证方法对用户身份、数字内容进行验证;协议中的一些计算由可信中心完成,以 减少移动用户的计算量,提高效率。另外在数字产品中嵌入版权水印和指纹水印,当发现非法副本时,它可以对叛逆 者进行追踪,具有可追踪性。分析表明,该协议是安全有效的。     

基于智能手机协议栈的虚拟Flash设备实现方法

一种基于智能手机协议栈的虚拟flash设备方法,简称VPSFD(Virtual Protocol Stack Flash Device).该方法的实现是在物理Flash设备上划分一块独立区间,将其模拟为一个物理设备,并以一套专用接口封装对其访问.独立于其他物理Flash访问接口,除了VPSFD设备其他接口不能访问.该方案通过智能手机和无线协议栈相结合,实现了高效、便捷的网络优化.     

智能建筑第三方开放式协议设备通讯中抗干扰技术研究

介绍了如何将第三方协议设备集成进Honeywell的EBI系统的方法,对其中影响RS485总线质量的抗干扰技术进行研究,分析了CRC校验码的纠错原理以及编译码过程.     

Two-Way Interconnection with Partial Consumer Participation

This paper incorporates partial consumer participation in a model of competition between telecommunications networks with two-way interconnection. It is shown, in contrast to the results of similar models with full participation, that the firms' equilibrium profits depend on the level of a reciprocal access charge under two-part retail pricing. Under some simplifying assumptions, it is shown that firms prefer the access charge be set equal to the marginal cost of termination, which coincides with the social optimum. Without these additional assumptions the model is analytically complex and simulation results are presented that suggest firms prefer the access charge to be less than marginal cost, while the socially optimal access charge may be above or below cost depending on the differentiation of the firms.     

一个新的适用于移动设备的双方身份认证与密钥共识协议

随着现代互联网的高速发展,人们通过网络进行远程通信变得越来越频繁。但是,在远程通信中如何确认通信双方的身份以及如何保证通信内容的安全,成为人们越来越关注的问题,身份认证与密钥共识协议就是用来解决这个问题的。在现有的身份认证与密钥共识协议中,有些协议在身份认证方面存在一些问题,在没有验证对方身份的前提下达成会话密钥是危险的。本文通过对Liang Ni等人协议的分析,提出了一个改进的身份认证与密钥共识协议,并对其安全性进行了分析。分析结果表明,新协议可以抵抗中间人攻击、假冒攻击等。而且,新协议中不包含双线性对运算,它特别适用于资源受限制的移动设备。     

支持双向验证的动态密文检索方案

动态可搜索加密技术实现了数据动态更新,可以应对更加灵活多变的应用挑战,但是对于数据更新时产生的隐私泄露以及用户与云服务器的不诚实性问题并没有解决.为了解决上述问题,提出了一种支持双向验证的动态密文检索方案,实现用户与云服务器之间的双向验证.首先,引入位图索引以及同态加法对称加密技术,使用位图索引表示单个关键字每次更新涉及的所有文档标识符,减少了云服务器搜索次数和本地索引加密次数,从而提高了搜索效率以及更新效率,并且利用同态加法对称加密对位图索引进行加密,可以有效地保护数据的安全更新.其次,将聚合消息认证码上传到区块链中,利用区块链对云服务器返回的结果进行正确性验证,防止用户和云服务器发生欺骗行为.最后,实验结果和安全分析表明,方案满足前向安全与后向安全,并且在索引生成、搜索、更新以及验证方面提高了效率.     

Imperfect fluid cosmology with heat flow

We discuss spatially homogeneous and locally rotationally symmetric Bianchi type V cosmological models under the influence of both bulk and shear viscosity coefficients with heat flow. Some exact solutions of the Einstein field equations are presented by using a law of variation for the generalized Hubble parameter that yields a constant value of the deceleration parameter. The law also generates power-law and exponential forms of the average scale factor in terms of the cosmic time t. To get a complete solution, a linear relation between the shear viscosity and the expansion scalar has been assumed. The presence of viscous terms, however, does not change the fundamental nature of the initial singularity. The solutions presented here satisfy all necessary conditions for physical acceptability. The thermodynamical relations, entropy production and energy condition in viscous fluid model are studied in detail.     

Lightweight and Secure Mutual Authentication Scheme for IoT Devices Using CoAP Protocol

Internet of things enables every real world objects to be seamlessly integrated with traditional internet. Heterogeneous objects of real world are enhanced with capability to communicate, computing capabilities and standards to interoperate with existing network and these entities are resource constrained and vulnerable to various security attacks. Huge number of research works are being carried out to analyze various possible attacks and to propose standards for securing communication between devices in internet of things (IoT). In this article, a robust and lightweight authentication scheme for mutual authentication between client and server using constrained application protocol is proposed. Internet of things enables devices with different characteristics and capabilities to be integrated with internet. These heterogeneous devices should interoperate with each other to accumulate, process and transmit data for facilitating smart services. The growth of IoT applications leads to the rapid growth of IoT devices incorporated to the global network and network traffic over the traditional network. This scheme greatly reduces the authentication overhead between the devices by reducing the packet size of messages, number of messages transmitted and processing overhead on communicating devices. Efficiency of this authentication scheme against attacks such as DoS (denial of service), replay attacks and attacks to exhaust the resources are also examined. Message transmission time reduced upto 50% of using proposed techniques.     

基于一种新VXIbus规范的网络仪器控制协议

TCP／IP-VXIbus接口规范,用于把VXIbus仪器用标准方式连接到一个TCP／IP计算机网络;文章给出了这个规范的目标以及网络仪器协议在TCP／IP—VXIbus接口设备内实现的LAN—to—VXI映射图．并用一个初级的LAN实例去帮助理解这项技术。     

Imperfect Evolutionary Systems

In this paper, we propose a change from a perfect paradigm to an imperfect paradigm in evolving intelligent systems. An imperfect evolutionary system (IES) is introduced as a new approach in an attempt to solve the problem of an intelligent system adapting to new challenges from its imperfect environment, with an emphasis on the incompleteness and continuity of intelligence. We define an IES as a system where intelligent individuals optimize their own utility, with the available resources, while adapting themselves to the new challenges from an evolving and imperfect environment. An individual and social learning paradigm (ISP) is presented as a general framework for developing IESs. A practical implementation of the ISP framework, an imperfect evolutionary market, is described. Through experimentation, we demonstrate the absorption of new information from an imperfect environment by artificial stock traders and the dissemination of new knowledge within an imperfect evolutionary market. Parameter sensitivity of the ISP framework is also studied by employing different levels of individual and social learning     

浅谈双向网改造技术方案

在进入“三网融合”的今天,全国广电网络面临着从单向单一的数字电视传输网络改为双向多功能多业务网,本文就以湄潭县城区有线电视传输网为例,根据目前网络实际情况出发,简单介绍几种进行低成本、高效率的双向改造组网方式,为了给更多的用户提供更加多的双向业务,建立稳定可靠、可运营、可持续发展的广电双向网络,最终达到三网融合。