Modbus设备嵌入式网页控制方法的研究与实现

为了具备与Internet的互联能力，遇到的首先就是协议转换的问题，本课题介绍如何将MODBUS协议转换为WEB服务器的HTTP协议，设计一个网关以及基于Cortex-M3微处理器结合RS232构建了Modbus协议转换模块。模块可通过RS232通讯方式与各种支持Modbus协议的设备进行通讯，可以将Modbus设备连入Internet，通过该模块的协议转换功能，能够通过Internet对Modbus设备实施网络化远程控制。     

ospf路由机制与安全性研究

ospf是一种基于链路状态的内部网关路由协议.本文介绍了ospf路由协议,分析了其链路状态数据库及其形成与维护,最后对ospf的安全机制进行了探讨和研究.     

基于TDMA的临近空间通信网MAC层协议仿真

运用网络仿真软件OPNET Modeler10.5作为开发环境,建立了临近空间通信网模型,设计了媒体接入控制(MAC)层的时分多址(TDMA)接入协议,实现了各个地面站对临近空间物理链路资源的有效共享.利用排队理论推导了该协议下的平均网络时延计算公式.收集的仿真结果表明,理论分析能够较准确地估计平均网络时延.     

HFDSR:一种新的短波分层网拓扑的路由算法

本文提出了一种短波分层网络路由算法HFDSR(High Frequency Dynamic SourceRouting),该算法是按需路由算法,由于短波信道具有带宽低、信道质量差的缺点,这势必要求其路由协议消耗尽可能低的网络开销并以链路质量为选径标准.分析和仿真结果表明,这种算法具有数据包发送成功率高,吞吐量大等特点.     

Arp欺骗实现网络准入控制方法分析

局域网中，通过ARP协议来完成IP地址转换为第二层物理地址（即MAC地址）的。ARP协议对网络安全具有重要的意义。通过伪造IP地址和MAC地址实现ARP欺骗，可以实现交换环境下的会话嗅探，第三方会话劫持攻击；不当的ARP欺骗可能导致整个局域网的不稳定甚至瘫痪；一些网络管理软件利用ARP欺骗也可以实现局域网强制接入的控制（如Internet上流行的“网络执法官”工具）。本文将详细分析ARP欺骗的工作原理，给网络可能造成的不稳定因素以及防范措施，并证明采用ARP欺骗技术实现网络接入控制的局限性。     

数据链传输IP分组的技术探讨

针对要求通过数据链远程控制计算机的实际需求,提出了利用数据链承载IP分组的方法.该方法通过使用专用网关设备连接有线和无线网络,实现了网间数据中继转发,同时利用轮询协议来规范无线链路的收发行为.测试结果表明,该技术简单适用,可以在地空通信中发挥较大作用.     

一种多信道的分簇式短波令牌协议

传统的短波令牌协议（HFTP）调度方式单一,在没有数据传送时,信道资源会被各节点间的令牌传递所占用,且令牌在通信质量较差时易丢失。基于此,提出一种多信道的分簇式短波令牌协议（CHFTP）,通过以通信质量评估为标准的分簇算法和基于预约的动态令牌调度,减小了令牌丢失的概率和令牌传递、处理的开销,并给出了仿真分析。仿真结果表明,该协议的端到端平均时延和网络吞吐量明显优于短波令牌协议,CHFTP的平均时延最多可减少75%,网络吞吐量最多可增加66.7%,适合在短波通信网络中使用。     

中继终端设备的天地网关功能设计与性能测试

近年来,空间网络协议大力发展,CCSDS空间网络协议体系已成为事实上的标准。基于跟踪与数据中继卫星系统（TDRSS）地面站中低速中继终端设备进行相应改造,增加网关路由板卡,加载CCSDS空间传输协议软件,将原来的中低速中继终端设备改造成带有路由网关功能的中低速中继终端设备。在此基础上,采用两台增加路由网关功能的中低速中继终端设备以及信道模拟器搭建天地网络演示验证系统,并分别对采用TCP协议和PEP增强协议作为传输层协议的HTTP应用进行了性能分析比对,证明PEP增强协议更能适应天地网络传输。     

小卫星星座非IP组网建模与仿真

针对移动IP技术需要依赖地面的家乡代理完成每个卫星地址注册与解析的不足,给出一种新的非IP构架的小卫星星座组网模型,并设计相应网络通信协议.组网模型不使用中高轨道卫星做数据与测控中继节点,在星际链路上使用定向天线指向器保证星际链路的连续性和链路切换.在OPNET平台上设计了通用的卫星节点通信模型和一个基于加权最短路径算法的卫星路由信息协议(SRIP),并进行了星座组网仿真实验.仿真结果验证了星座组网模型设计的正确性.该模型为小卫星星座依赖于自身网络,而不依赖于中高轨道卫星做中继完成网络测控提供了一种新思路.     

低轨卫星接入系统中基于位置信息的时隙分配协议

针对浮标卫星通信系统中卫星覆盖范围广、接入链路传播时延差异大的场景结构引起的统一延迟分配协议中端到端时延长、吞吐率低的问题,提出了一种基于位置信息的时隙分配协议。协议中卫星通过获取浮标位置信息来控制时隙分配的起点,实现时隙离散分配,增大可用传输时隙长度,同时降低传输时延。OPNET 仿真结果表明所提出的时隙分配协议可以显著提高单信道传输模式下的网络吞吐量,并有效降低单信道与双信道模式下浮标卫星通信系统接入时的端到端时延。     

Pricing Internet access in the presence of user loyalty

Socio-economic aspects of future communication networks such as pricing models for network providers, network neutrality, and Quality of Experience (QoE) are becoming more and more important as the convergence of networks is in progress. All the above areas share a common interest: the deeper understanding of user behavior. In this paper, as a first step towards a more realistic user model, we investigate customer loyalty and its impact on the pricing competition of Internet Service Providers (ISPs) who sell Internet access to end-users. The main contribution of this paper is twofold. First, we analyze the impact of user loyalty with game-theoretical means motivated by the Bertrand game. We show how loyalty introduces a new equilibrium in a repeated game setting resulting in the cooperation of ISPs. Furthermore, we investigate the case of a differentiated customer population by introducing dual reservation values, and show how it leads to new, pure strategy Nash equilibria indicating that ISPs should make the most out of their respective loyal user base. Second, we construct two novel models for customer loyalty incorporating two important aspects of the users’ purchasing decisions: price sensitivity and inherent uncertainty. We evaluate the impact of user loyalty through these models by extensive simulations in a number of relevant scenarios. In particular, we show how the higher level of loyalty in the user population leads to larger profits for ISPs. We argue that our findings can motivate network researchers to incorporate a finer-grained user behavior model in their investigations on pricing models of network services and other socio-economic issues.     

Device-mediated customer behaviour on the internet: A systematic literature review

The proliferation of smartphones, tablets and other digital devices in addition to traditional computers has transformed the Internet into a device-mediated environment. While these devices provide immediate access to similar Internet sources, they differ significantly in their characteristics, such as screen size, operation mode and context of use. As a consequence, behaviours on the Internet along the customer journey vary substantially depending on the device used. To summarize the fast-growing body of research on device-mediated customer behaviour, a systematic, framework-based literature review of 59 articles from the last decade was conducted. Through an examination of the antecedents, decisions and outcomes investigated in the publications, the review presents a conceptual framework that highlights the relation between device characteristics, decision processes and behavioural outcomes. The review further summarizes the theories, contexts and methods employed in the studies and sets an extensive future research agenda. We found that the extant literature lacks comprehensive theories and clear definitions of digital devices in the omnichannel environment. Furthermore, existing findings should be generalized for other contexts (e.g. industries and countries) and validated via the introduction of other research designs and methods. The understanding of device-mediated behaviour and the consequently arising marketing measures remains scarce. Thus, this review advances the comprehension of customer behaviour on the Internet and provides researchers and practitioners with information on the implications for customer experience and omnichannel management.     

Flexible Geschäftsmodelle in der Telekommunikation und die Netzneutralitätsdebatte

The net neutrality debate concerns the differential treatment of data on the Internet and the pricing models used by enduser internet service providers (IPSs). In particular, end-user ISPs may want to prioritize certain services and charge on the sender or the receiver side for this activity. In the policy debate it is asked whether regulatory intervention is warranted to restrict such behavior. The introduction of new end-user tariffs for fixed-line Internet access by Deutsche Telekom has heated up the debate in Germany. At the national level, the German Ministry of Economics and Technology has prepared a draft regulation on net neutrality, which aims at limiting the differential treatment of data transmission on the internet including the access networks and, thus, to protect the “Open Internet”. The European Commission has prepared an alternative draft regulation for a single European market in telecommunications, which contains provisions for an “Open Internet”. In this article, the authors investigate the extent to which the new tariff structure by Deutsche Telekom relates to the net neutrality debate. They also provide a first critical analysis of the proposals by the German Ministry of Economics and Technology and the European Commission.     

卫星通信网络和短波/超短波通信网络的互连

基于未来战争对于无线通信系统集成化、综合化的要求。通过对卫星网络、短波／超短波网络的深入研究，设计了一个新型的无线通信系统，该系统不但可以同时接入上述3种网络实现不同系统的连接，也可以单独作为某一无线网络而独立应用，对未来的军用无线系统研究有一定的参考价值。     

Internet user behaviour in France and Britain: exploring socio‐spatial disparity among adolescents

The Internet has radically transformed society – although its diffusion has been uneven. Various studies of digital inequality have been undertaken in Anglo‐Saxon communities. Few studies have investigated digital inequality from a socio‐spatial perspective (urban vs. suburban, rather than urban vs. rural) in a French setting. This absence underscores a gap in knowledge and methodology. It highlights the complexities of gathering comparable data on Internet user behaviour beyond national borders. This paper takes a multidisciplinary approach to investigate emerging trends in Internet use across different territories (inner‐city and suburban, as opposed to urban vs. rural) by means of in‐depth interviews with Internet users aged 13–15 years old in France and Britain. The aim is to provide a broad understanding of the way in which teenage Internet users behave online in different territories. The investigation reveals a number of converging trends that are common to both France and Britain and some unexpected disparity.     

终端准入控制解决方案在检验检疫信息安全工作中的应用研究

重点阐述终端准入控制解决方案的原理,介绍其在上海出入境检验检疫局的成功上线过程,并且对解决方案上线后的容灾备份方案进行了详细论述。通过终端准入控制解决方案部署,解决检验检疫信息化推进过程中网络安全等问题,加强检验检疫内网安全防御能力,提升内网的整体安全。     

Exploring the intention to continue using web-based self-service

The popularization of Internet and the development of cloud computing have not only changed our lifestyles, but have impacted the ways in which enterprises relate with their customers. For example, customers and enterprises can now directly interact through web-based self-services (e.g., Internet banking, online ticketing, online bookstores, and online reservations) that do not require face-to-face interactions. Web-based self-services (WBSS) allow enterprises to proactively initiate contacts with customers and respond to their needs. Customers can also quickly access the services they want online, at any time and place, thus enhancing overall service efficiency. However, a review of the previous literature shows that most related studies have used the Technology Acceptance Model, which examines perceived usefulness, perceived ease of use and attitude toward use, in order to investigate user behaviors when operating a WBSS. In contrast, there are few studies that examine the impact of perceived usefulness and perceived quality features on the continued intention to use a WBSS. Therefore, this study applied the questionnaire method and investigated the relationships among users’ perceived usage characteristics, quality characteristics, satisfaction and continued usage intention with regard to WBSS. Based on the results, specific recommendations are provided for enterprises to enhance the intention to continue using WBSS.     

产业互联网平台价值共创机理——基于宏图智能物流的案例研究

文章通过宏图智能物流的案例分析,揭示产业互联网平台价值共创的机理。研究发现,产业互联网平台价值共创过程包括平台启动、平台成长和平台拓展三个阶段。产业互联网平台价值共创机理主要体现为平台企业基于瓶颈问题甄别,实施分阶段差异化的平台架构设计,推进平台与产业环节上多边用户的价值共创。在平台启动阶段体现为平台架构归核,通过平台架构精炼和用户关系连接解决用户体验梗阻问题;在平台成长阶段体现为平台架构扩核,通过平台垂直整合和用户关系嵌入解决平台优势弱化问题;在平台拓展阶段体现为平台架构嵌套,通过平台水平包络和用户关系锁定突破平台拓展困境。与消费互联网平台强调用户规模的快速增长不同,产业互联网平台更强调用户深度参与共创实现效率提升。     

Antecedents of Perceived Quality in the Context of Internet Retail Stores

This study investigates specific antecedents of perceived service quality in the Internet environment for trust to a retail store, experience with e-commerce, Internet familiarity, excitement with e-commerce, extent of using e-commerce, frequency of purchases from a company, in addition to exploring the reasons for shopping on line: such as price discounts, convenience, product availability, and purchase conditions. The results indicate that perceived e-service quality is comprised of four key dimensions: information, user friendliness, interaction / adaptation and aesthetics. Moreover, the study reveals that different dimensions of perceived e-service quality are influenced by diverse antecedents. For instance, whilst customer trust to a company influences all four dimensions, Internet familiarity has an impact solely on user friendliness. This picture remained when the type of store, either pure dot. com versus hybrid retailer, was tested as a moderator variable. Implications for practice, the limitations of the study, and directions for future research are discussed.