基于CoAP协议可靠组通信系统的设计及实现

为了解决资源受限传感器网络中的CoAP协议组通信不可靠性的问题,采用基于代理服务器的方式,给出了CoAP协议可靠组通信系统的设计方案,并通过仿真系统模拟实现了此方案。针对接收端节点数量的不同,分别采用基于代理服务器和单播重传的方式实现了该系统的构建,为CoAP协议可靠组通信方案的构建提供了理论模型和架构基础。     

基于DMSP共享的移动多播方案

RBMoM是一种综合了IETF的移动IP协议中远程加入和双向隧道两种基本方法、综合性能较优的移动多播协议。文中通过分析RBMoM移动多播协议中存在的问题,提出了DMSP共享机制,基于此机制实现了一个高效的移动多播方案。该方案有效地减少了网络中的多播通信量并降低了多播树的维护代价,却没有给多播数据传输带来太大的延迟。     

基于UDP多播文件传输方法的研究

本文阐述了以UDP无连接数据报为基础的可靠多播协议实现原理和技术,解决了在Windows平台下的多播文件传输问题。主要采用了数据包乱序接收技术和主从客户端批量数据接收技术。     

一种基于遗传算法的半动态应用层多播协议

将半动态应用层多播通信分解为静态起始和动态维护两种阶段交替出现的过程．在起始阶段．采用基于遗传算法的多播路由机制构建优化的静态多播树；在维护阶段，采用拓扑维护机制、路由性能监控机制和路由更新机制．对多播拓扑的动态进行快速响应．仿真结果表明．该协议同时具备优化多播树性能和快速维护多播拓扑的能力，改善了通信过程中多播树的整体性能．     

基于转接节点的可靠多媒体多播协议

研讨了多媒体多播应用中的允许延迟和分组丢失率问题，提出了一种基于转接节点概念的可靠多播协议（RMPRM）。RMPRM协议聚焦在允许延迟上提供多媒体服务质量保证，转接节点放置在多播树上，数据恢复在两个转接节点之间进行。RMPRM协议转接能满足重传需求和减少分组的复制数量。给出了RMPRM协议与不可靠多播协议的比较。仿真实验表明，该协议具有较高的传输率和较低的端到端的传输延迟。     

MPLS多播技术研究

本文深入讨论了支持多播的MPLS关键技术问题,包括标记交换的发起方式及其性能特征、信令的选择、多播路由协议行为对MPLS多播实现技术的影响等。最后综合多种技术因素,提出可行的MPLS多播方案,并明确了需要进一步解决的一些其他重要技术问题。     

基于ODMRP的可靠多播路由协议

基于按需多播路由协议(ODMRP),提出一种改进的可靠多播路由协议。该协议采用集中报错机制,在尽量不增加控制分组数目的前提下,将一定数量的数据分组丢失事件集中在一个聚合的NACK中,并将该NACK添加到Join Table分组中,通过上游节点重传实现ODMRP协议的可靠传输。在OPNET下进行仿真实验,结果表明,与原协议相比,改进协议的数据包投递率提高了2.5%。     

计算机网络中的多播路由问题

在计算机网络中，多播是目前研究最多、应用最广的连接方式。就目前存在的多播路由算法及路由协议进行了分析与总结，给出了解决多播问题的一般方法，提出了在光网络中推行多播的必要性。     

基于Internet的可靠多播传输协议

对于大规模多媒体多播应用来说，一个有效发现和修正传输错误的可靠多媒体多播传输协议是必要的。研讨了多媒体多播应用中的传输延迟和分组丢失率问题，提出了一种基于转接节点概念的Internet可靠多播传输协议（IRMTP）。IPMTP协议聚焦在一定延迟上提供多媒体服务质量保证，转接节点放置在多播树上，数据恢复在两个转接节点之问进行，IRMTP协议能满足分组重传需求和减少分组的传输延迟。给出了IRMTP协议与SRM协议的性能比较，仿真实验表明，IRMTP协议能提供较高的传输率和较低的端到端分组传输延迟。     

基于LKH树的动态多播群组批密钥更新方案的优化设计

逻辑密钥层次（LKH）方案是目前多播领域中最有效的密钥管理协议。然而，由于其集中式访问控制和密钥分配方式，限制了组规模的进一步扩展。根据文献[1，2]关于MBone的多播组成员行为的研究和监测结果，援引批处理和优化控制的思想，本文对LKH树的方案进行了改进和扩展，设计了一个基于LKH树的优化批密钥更新方案，并给出了它的协协议和算法。分析表明，该方案克服了原有协议的缺点，增加了组规模的可扩展性，因而适用于大型的动态多播环境。     

Privacy‐preserving targeted mobile advertising: requirements,design and a prototype implementation

With the continued proliferation of mobile devices, the collection of information associated with such devices and their users—such as location, installed applications and cookies associated with built‐in browsers—has become increasingly straightforward. By analysing such information, organisations are often able to deliver more relevant and better focused advertisements. Of course, such targeted mobile advertising gives rise to a number of concerns, with privacy‐related concerns being prominent. In this paper, we discuss the necessary balance that needs to be struck between privacy and utility in this emerging area and propose privacy‐preserving targeted mobile advertising as a solution that tries to achieve that balance. Our aim is to develop a solution that can be deployed by users but is also palatable to businesses that operate in this space. This paper focuses on the requirements and design of privacy‐preserving targeted mobile advertising and also describes an initial prototype. We also discuss how more detailed technical aspects and a complete evaluation will underpin our future work in this area. Copyright © 2016 John Wiley & Sons, Ltd.     

Energy-efficient mobile web in a bundle

The mobile Internet that was a huge hype ten years ago is finally here. We have a wealth of mobile devices that allow us to enjoy and consume Internet content from any number of web sites and services. With faster processors and radio links, our use of the Internet and the traffic mobile users generate grows at a tremendous pace. In this development, we still have a huge challenge to tackle: energy efficiency. When ten years ago one would recharge his personal mobile device once a week, we now do that daily; Smart phones today are not able to carry enough energy to allow us several days of usage time. The focus on this paper is to present and analyse one solution to help us in our daily lives. We implement and study a scheme where web content, a page, is delivered as a whole to a mobile device, instead of sending each individual object of the page separately. Combined with RRC state based header compression and selective content compression, our proposal allows the radio to keep in low power state for longer durations, and as a consequence brings huge energy savings. Download times also decrease, thus bringing increased Quality of Experience.     

Modeling resource constrained BitTorrent proxies for energy efficient mobile content sharing

In this paper we present a solution that makes BitTorrent content transfer for mobile device more energy efficient. The main idea of the research is that instead of downloading the content via BitTorrent directly to the mobile phone, an intermediate proxy is used which sends the data to the phone in high speed bursts. This results in smaller energy footprint compared with regular BitTorrent data transfer. Furthermore, we focus on how the proxy can be hosted on memory limited broadband routers which are available in almost every home. We define an analytical model which can be used to analyze the memory allocation strategies of the proxy peers and predict how proxy peers influence the P2P community performance. We verify our model via simulations. We also present measurement results with real life torrents using our prototype system running on home routers and Symbian based mobile phones.     

A Bayesian exploration-exploitation approach for optimal online sensing and planning with a visually guided mobile robot

We address the problem of online path planning for optimal sensing with a mobile robot. The objective of the robot is to learn the most about its pose and the environment given time constraints. We use a POMDP with a utility function that depends on the belief state to model the finite horizon planning problem. We replan as the robot progresses throughout the environment. The POMDP is high-dimensional, continuous, non-differentiable, nonlinear, non-Gaussian and must be solved in real-time. Most existing techniques for stochastic planning and reinforcement learning are therefore inapplicable. To solve this extremely complex problem, we propose a Bayesian optimization method that dynamically trades off exploration (minimizing uncertainty in unknown parts of the policy space) and exploitation (capitalizing on the current best solution). We demonstrate our approach with a visually-guide mobile robot. The solution proposed here is also applicable to other closely-related domains, including active vision, sequential experimental design, dynamic sensing and calibration with mobile sensors.     

Understanding dynamics between initial trust and usage intentions of mobile banking

Mobile banking is an emerging application of mobile commerce that could become an additional revenue source to both banks and telecom service providers. It is a form of service convergence enabled by innovative technologies. Despite the alleged benefits of mobile banking, its acceptance has been short of industry expectations. One plausible explanation may be consumers' initial lack of trust in available services. The objective of our research is to reveal the mechanisms associated with the initial formation of people's trust in mobile banking and intention to use the service. For this, we attempt to understand the effect of four antecedent variables (structural assurances, relative benefits, personal propensity to trust and firm reputation) on shaping a person's initial trust in mobile banking and its usage intention. They represent four types of trust-inducing forces: institutional offering (structural assurances), cognition (perceived benefits), personality (personal propensity) and firm characteristics (firm reputation). We examine individual significance of the selected antecedents and also their comparative reliability in explaining the two exogenous variables. The technical basis of our empirical research is the innovative mobile banking solution that uses cellphones with a built-in smart chipset. The survey data are analyzed using structural equation modelling. The analysis showed that three variables (relative benefits, propensity to trust and structural assurances) had a significant effect on initial trust in mobile banking. Also, the perception of initial trust and relative benefits was vital in promoting personal intention to make use of related services. However, contrary to our expectation, the reputation as a firm characteristics variable failed to attract people to mobile banking.     

SIPmsign: a lightweight mobile signature service based on the Session Initiation Protocol

The development of mobile signatures could increase the spread and adoption of mobile services based on electronic signatures, such as mobile payments, mobile business transactions, and mobile government services. A Mobile Signature Service (MSS) means that a user in any of the scenarios mentioned can attach an electronic signature, anywhere, anytime, as with a handwritten signature with a device that is almost always on him or her. Several solutions have appeared, such as using the European Telecommunications Standard Institute MSS, the Mobile Signature Application Unit, and the Mobile Network Operator‐independent MSS. These solutions present two kinds of drawbacks. On the one hand, some of them require the service to be developed by all mobile network operators, whereas others are not based on efficient communications. In this paper, we present a new MSS named SIPmsign that solves these problems. Our proposal is based on the Session Initiation Protocol and defines how to exchange the information in a secure and more efficient way than previously. Thanks to Session Initiation Protocol, we provide the adoption of our proposal as a MSS for the new generation of mobile communications. In this paper, we also present the prototype we have developed as a proof of its feasibility as well as an evaluation of the performance of our solution. Copyright © 2012 John Wiley & Sons, Ltd.     

Collision Avoidance by Using Space-Time Representations of Motion Processes

This paper handles the problem of collision avoidance in a multi-robot environment. To solve this problem, the motion processes of the mobile robots are modelled in space-time. Since the robots are autonomous and communication is non-deterministic, there is temporal uncertainty in addition to spatial uncertainty. The paper presents a method to model both uncertainty components in a homogeneous way. It is shown, that it is not sufficient to guarantee a spatial security distance between the robots. Distances in space-time and space-time vectors must be considered. The main result of this paper is a straightforward and efficient solution to the problem of collision avoidance between up to three mobile robots by applying a space-time displacement vector. The solution is based on space-time, which is a helpful view onto our world in relativity theory and quantum physics. Space-time methods are also very valuable in Robotics, especially for problems in dynamic environments and for motion coordination of mobile robots. Practical experiments with up to two robots, and simulations of up to three robots have been performed and are reported.     

移动设备在系统中的集成方案

移动技术的应用延伸了客户端用户对空间位置的需求，使这些企业平台进一步扩展变为现实。如何利用移动设备的便携性和后台处理的强大功能，是一个值得研究的课题。在分析现有移动开发方法和开发平台的基础上，提出了一种四层软件模型的解决方案。模型可以对现有系统进行兼容，在保持原有系统的基础上对其进行移动扩展。     

Reliable Communication for Highly Mobile Agents

The provision of a reliable communication infrastructure for mobile agents is still an open research issue. The challenge to reliability we address in this work does not come from the possibility of faults, but rather from the mere presence of mobility, which complicates the problem of ensuring the delivery of information even in a fault-free network. For instance, the asynchronous nature of message passing and agent migration may cause situations where messages forever chase a mobile agent that moves frequently from one host to another. Current solutions rely on conventional technologies that either do not provide a solution for the aforementioned problem, because they were not designed with mobility in mind, or enforce continuous connectivity with the message source, which in many cases defeats the very purpose of using mobile agents.In this paper, we propose an algorithm that guarantees delivery to highly mobile agents using a technique similar to a distributed snapshot. A number of enhancements to this basic idea are discussed, which limit the scope of message delivery by allowing dynamic creation of the connectivity graph. Notably, the very structure of our algorithm makes it amenable not only to guarantee message delivery to a specific mobile agent, but also to provide multicast communication to a group of agents, which constitutes another open problem in research on mobile agents. After presenting our algorithm and its properties, we discuss its implementability by analyzing the requirements on the underlying mobile agent platform, and argue about its applicability.     

基于区块链的可信移动应用市场

针对普通用户无法鉴别移动应用市场是否可信,以及移动市场恶意行为难以追溯的问题,提出基于区块链的可信移动应用市场的方案。该方案将区块链去中心、防篡改、可追溯的安全特性应用于移动应用的发布与传播,实现应用开发方、应用市场以及用户的互联互通互信,确保了移动应用源头可查证,完整性可验证,流转轨迹可追溯,恶意行为难抵赖。分析表明,本文方案能够建立可信的移动应用生态,提高移动应用的安全性。