Compressed and Distributed File Formats for Labeled Transition Systems

With model checking techniques growing towards maturity, the availability for standardised file formats for labeled transition systems is more important than ever. A number of requirements for file formats are introduced, based on requirements for software, databases and compression. Two candidate formats, SVC I and SVC II are introduced, with the former emphasising compression and the latter focusing on distributed access. The two formats are compared with existing file formats.     

移动GIS切片地图展现技术

地图是GIS（地理信息系统）操作的入口,如何快速地显示地图是GIS首要考虑的问题．快速展现地图主要涉及到地图数据的组织和地图展现技术两方面的问题．目前,以谷歌地图为代表的商业地图软件大都采用地图切片的方式组织地图数据,这种方式被认为是快速且有效的．本文采用上述方式组织地图数据,使用切片并发控制技术和切片双缓存技术主要对移动GIS切片地图展现的相关技术进行研究,旨在提供一种快速展现切片地图的方法．基于本文的研究成果,作者分别在WindowsMobile和Android平台上实现了移动GIS系统,并成功应用于实际项目中．     

移动定位技术和移动定位系统

移动终端的位置是移动互联网中的关键信息.本文从移动定位技术、典型的移动定位系统及当前研究热点等方面对其进行了阐述.     

Self-Management Framework for Mobile Autonomous Systems

The advent of mobile and ubiquitous systems has enabled the development of autonomous systems such as wireless-sensors for environmental data collection and teams of collaborating Unmanned Autonomous Vehicles (UAVs) used in missions unsuitable for humans. However, with these range of new application-domains comes a new challenge—enabling self-management in mobile autonomous systems. Autonomous systems have to be able to manage themselves individually as well as form self-managing teams which are able to adapt to failures, protect themselves from attacks and optimise performance. This paper proposes a novel distributed policy-based framework that enables autonomous systems of varying scale to perform self-management individually and as a team. The framework allows missions to be specified in terms of roles in an adaptable and reusable way, enables dynamic and secure team formation with a utility-based approach for optimal role assignment, caters for communication link maintenance amongst team-members and recovery from failure. Adaptive management is achieved by employing a policy-based architecture to enable dynamic modification of the management strategy relating to resources, role behaviour, communications and team management, without interrupting the basic software within the system. Evaluation of the framework shows that it is scalable with respect to the number of roles, and consequently the number of autonomous systems involved in the mission. It is also optimal with respect to role assignments, and robust to intermittent communication link and permanent team-member failures.     

移动组件系统模型的分析与描述

移动计算是新兴的分布式计算范型,其主要特征是计算组件与计算场所能动态改变绑定关系,表现出移动性,从而带来许多新的系统设计需求.从系统模型层次角度对位置、移动组件、移动和资源访问等移动计算核心概念,以及组件与位置之间的各种关系和关系变化刻画的移动范型进行了描述.通过使用集合论和操作语义的规约规则形式地表示这些概念、关系和移动机制,进而抽象出移动系统设计所需的语言结构,为移动系统设计和开发提供了分析基础.     

Language-based Performance Prediction for Distributed and Mobile Systems

We present a framework for performance prediction of distributed and mobile systems. We rely on process calculi and their structural operational semantics. The dynamic behaviour is described through transition systems whose transitions are labelled by encodings of their proofs that we then map into stochastic processes. We enhance related works by allowing general continuous distributions resorting to a notion of enabling between transitions. We also discuss how the number of resources available affects the overall model. Finally, we introduce a notion of bisimulation that takes stochastic information into account and prove it to be a congruence. When only exponential distributions are of interest our equivalence induces a lumpable partition on the underlying Markov process.     

Application Security Models for Mobile Agent Systems

Mobile agents are a distributed computing paradigm based on mobile autonomous programs. Mobile applications must balance security requirements with available security mechanisms in order to meet application level security goals. We introduce a trust framework to reason about application security requirements, trust expression, and agent protection mechanisms. We develop application security models that capture initial trust relationships and consider their use for mobile agent security.     

移动终端系统的访问控制框架

随着移动计算的不断普厦,针对移动终端的安全问题日益受到重视。传统的访问控制技术能够解决机密性和完整性问题,但没有充分考虑可用性要求。移动终端同个人计算机相比更容易耗尽系统资源,受到拒绝服务攻击。本文提出一种应用于移动终端的访问控制框架,扩充DTE机制,保证数据机密性和完整性,并允许关键应用预留动态资源（如CPU时间、物理内存页面等）,系统对预留的资源进行统一的调度和管理,防止关键应用与其它程序竞争系统资源时产生冲突,保证系统对关键应用的响应,提高系统的可用性。     

面向移动边缘的组合服务选择及优化

移动边缘计算作为新型的计算范式,为降低网络延迟、能耗开销提供了新的思路.其将中心云的强大算力下沉至网络边缘,使得用户能够将计算任务卸载至物理位置更近的边缘服务器执行,从而节省经由核心网的时延与能耗开销.然而,由于移动边缘计算技术通常受到计算资源、网络传输带宽、设备电量等因素的制约,如何在有限的资源中获取最大的利用率成为...     

Correlation-Extremal Systems for Navigation and Location of Mobile Objects

The paper reviewed the studies of Tomsk researchers in the area of correlation-extremal navigation systems with emphasis on analysis and design of the systems of extremal passive location.     

移动推荐系统及其应用

近年来,移动推荐系统已成为推荐系统研究领域最为活跃的课题之一.如何利用移动上下文、移动社会化网络等信息进一步提高移动推荐系统的推荐精确度和用户满意度,成为移动推荐系统的主要任务.对最近几年移动推荐系统研究进展进行综述,对其关键技术、效用评价以及应用实践等进行前沿概括、比较和分析.最后,对移动推荐系统有待深入的研究难点和发展趋势进行分析和展望.     

Mutual Anonymity for Mobile P2P Systems

Mobile peer-to-peer networks (MOPNETs) have become popular applications due to their ease of communication and resource sharing patterns in unfixed network infrastructures. As privacy and security are coming under increasing attention, many mobile and ad hoc network protocols attempt to provide mutual anonymity for users. Most existing anonymous designs, however, are path based, where the anonymous communications are achieved via a predetermined path. Such a design suffers from unreliable delivery and high processing overheads and is not practical. We propose a scalable secret-sharing-based mutual anonymity protocol, termed PUZZLE, which enables anonymous query issuance and file delivery for MOPNETs in ad hoc environments by employing Shamir's secret sharing scheme. We present the design of PUZZLE, analyze its degree of security and anonymity, and evaluate its performance by comprehensive trace-driven simulations. Experimental results show that compared with previous designs, PUZZLE achieves mutual anonymous communications with a lower cryptography processing overhead and higher degree of anonymity.     

考虑位置失效的移动系统安全模型

以带位置扩展的移动进程π演算模型为形式化工具,在考虑位置失效的基础上,将移动系统的安全性质转换为系统进程在给定计算环境中的位置互模拟关系,提出了考虑位置失效的一种新安全模型。针对实际安全需求,该模型可以方便地描述不同的非干扰安全性质;该模型提供了一个统一的安全分析架构,可广泛用于移动计算系统的安全性分析。     

一种用于移动机器人遥操作的传输协议

针对移动机器人Internet遥操作系统中存在着将无线丢包误认为拥塞丢包的问题,提出了一种传输协议TFRC-PROBE。它使用了一个探测主机来实时监测移动机器人和网关服务器之间的无线连接状态,从而区分移动机器人发送视频反馈及其他反馈信息的时候数据包丢失的类型。然后远程移动机器人使用一个基于TFRC的改良的发送速率计算公式来计算发送视频反馈及其他反馈信息的速率。使用NS-2的仿真结果显示TFRC-PROBE能大幅度提高网络的吞吐量,并且具有TCP友好的特性。     

MIMO通信系统的移动台单站定位算法

无线MIMO通信系统中在发射和接收端使用天线阵列,充分利用冗余多径信号结合阵列信号处理技术可提取出更多参量,比如AOA、AOD、DOA。该文基于MIMO通信系统多径信号参量的估计,推出一种单基站定位的新方法。该方法将多径参数误差的出现概率降到最低并通过同时解一系列数学定位方程给出移动台位置定位的最佳估计。测量均方误差并与克拉美罗界下界比较,证明了该方法的性能。     

Rule Formats for Timed Processes

Building on previous work (15,8), this paper describes two syntactic ways of defining ‘well-behaved’ operational semantics for timed processes. In both cases, the semantic rules are derived from abstract operational rules for behaviour comonads and thus ensure congruence results. The first of them, a light-weight attempt using schematic rules, is shown to be sound, i.e., to indeed induce abstract rules as introduced in [8]. Then a second format, based on a new and very general kind of abstract rules, comonadic SOS (CSOS), is presented which uses meta rules and is also complete, i.e., it characterises all possible CSOS rules for timed processes.     

A Flexible and Energy-Efficient Coarse-Grained Reconfigurable Architecture for Mobile Systems

Two of the most important design issues for next generation handheld devices are wireless networking and the processing of multimedia content. Both applications rely heavily on computationally intensive digital signal processing algorithms. Programmable architectures that keep pace with the increasing performance requirements become more and more power hungry. This is problematic for a battery powered mobile device, since it has only a limited amount of energy available. Conversely, dedicated architectures are too inflexible to keep pace with changing standards and feature sets. A mobile device requires high-performance, flexibility and (energy-)efficiency. These contradicting requirements need to be balanced in the system architecture of a mobile device. In this paper a heterogeneous architecture of domain specific processing tiles is proposed. The focal point is the coarse-grained reconfigurable architecture of the Montium processing tile, which is designed to execute digital signal processing algorithms energy-efficiently.     

移动数据库同步复制和缓存的一种策略

根据移动数据库系统的应用特殊性,提出了一个基于数据表划分和优先级的移动数据库同步复制与缓存的策略.通过数据表的划分,减少了所要传送的事务量和数据量;而使用优先级也减少了夭折事务的数据传输量,从而降低了对整个通信带宽的消耗.     

Coordinated Handover Initiation and Cross-Layer Adaptation for Mobile Multimedia Systems

A cross-layer mechanism to improve the performance of real-time applications over IEEE 802.16e metropolitan area networks is presented. The proposed mechanism uses channel quality and service quality information from the physical and medium access control layers, respectively, to determine the most suitable burst profile, transmission power level and media encoding rate for a connection, or even initialize a handover execution. The main contribution of this mechanism is the integration of the handover initiation into the cross layer logic, aiming to improve the overall system performance. Extensive simulation results show that the proposed mechanism offers significant performance improvement in terms of packet loss rate, power consumption, throughput, and system capacity.