一种虚拟场景控制方法的研究与实现

针对虚拟场景中视点控制和模型控制两种情况,研究了应用二维鼠标和三维输入设备拾取三维对象模型、移动对象模型和在虚拟场景中漫游的方法,提出了一种用二维鼠标拾取三维模型的方法——粗区域判断、最近拾取,并基于Vega视景仿真开发平台和VC++提出了一种基于二维鼠标拾取、三维输入设备移动的虚拟场景控制方法。     

面向普适计算的动态自适应中间件模型

为了提高普适计算系统的开发效率, 设计了一个基于OSGi框架的动态普适计算中间件模型. 该中间件模型以OSGi框架为基础, 建立移动管理器管理用户和服务的移动, 利用上下文管理器来管理上下文, 动态调整自己的行为, 支持上下文感知应用. 通过标准的接口实现各种异构普适设备间的互操作性. 实验结果表明该中间件能够满足通用普适计算环境的要求, 对于普适计算系统的开发具有一定的借鉴意义.     

移动普适环境中支持QoS控制的安全框架研究

基于对移动普适计算环境所面临的安全威胁的分析,从用户,网络和服务提供商3个方面总结了移动普适计算环境的特殊安全需求,并提出一种适用于移动普适计算环境且支持QoS(quality of service)控制的安全框架.对该框架的相关功能操作和工作时序进行了介绍,并着重研究和实现了安全框架中的QoS控制流程.通过此框架,移动互联网设备用户可以随时随地访问移动普适计算环境并获得高质量的安全服务.     

基于Virtools的虚拟化工厂三维模型的优化

利用虚拟现实技术实现了虚拟化工场景,讨论三维场景建模技术和三维场景优化技术,深入研究了场景优化技术中的LOD技术和面片网格简化方法,将它们作为离散LOD模型的生成方式.对于建模过程中出现的面数过多,场景巨大等问题,使用了可见性裁剪,模型简化与多分辨率造型等方法进行实验,利用Virtools软件对虚拟化工场景进行优化与漫游功能的实现,提出了一种基于Virtools软件在视景系统中进行三维模型优化的方法.     

面向移动终端的三维模型简化与碰撞检测方法研究

移动终端三维场景的绘制与漫游由于其庞大的模型数据量和复杂的外观形态使得实现清晰的场景快速绘制十分困难。为了加快模型的绘制,提出了一种面向移动终端的三维模型的简化与碰撞检测方法,以优化绘制过程。该方法通过二次测量误差半边折叠算法来简化三维模型,并利用八叉树技术对不能显示在屏幕中的场景进行剔除,从而实现三维场景的快速读取、组织和绘制。针对移动设备的屏幕尺寸以及计算能力等限制,实现了适用于移动平台的碰撞检测算法,减少了计算量。实验结果表明,该方法能有效地简化模型,并提高绘制效率,同时减少碰撞检测的计算时间,因而可应用于三维场景的快速逼真绘制。     

三维虚拟火电厂参数化模型库的实现

为提高火电厂三维虚拟建模的效率,结合火电厂设备的特点,提出基于Pro/E二次开发技术Pro/Toolkit的参数化设计流程和方法。对三维虚拟火电厂的架构进行认知,明确火电厂应用领域参数化建模的要求;以Pro/E软件为开发工具,通过分析比较其二次开发工具的优劣,选择Pro/Toolkit技术来完成开发设计;在此基础上设计三维虚拟火电厂常用设备组件的参数化模型库,使用VC++编程语言实现友好、高效的交互界面,以电力变压器为实例阐述基于Pro/toolkit二次开发技术的参数化设计过程。该方法解决了采用三维实体造型技术来进行三维建模时重复建模、工作量大、效率低下等问题,提高了建模效率,降低了建模难度,节约了建模成本。     

面向普适计算应用的仿真测试技术研究

评估普适计算应用的可用性是一项需要时间和精力投入的复杂工程。传统的测试技术依赖系统的全面部署和实现,并且测试者需要了解测试环境的搭建方法,这无疑增加了普适计算应用的测试成本。本文重点研究了面向普适计算应用的仿真测试关键技术,提出了虚拟测试环境,实现了对计算环境和设备能力的模拟。在此基础上,提出基于构件结构的测试系统,模拟对资源的远程访问能力和应用的自适应执行操作,为评估普适计算应用提供支持。     

基于VRML的三维虚拟校园漫游系统的研究

利用VRML(Virtual Reality Modeling Language)的虚拟建模语言的开发技术,提出解决三维虚拟校园场景实体建模方法,确定基于VRML感知器和Cortona VRML Client浏览器对场景中对象行为的控制,并对三维建模、纹理映射、碰撞检测、VRML场景优化技术等问题进行了探.     

基于CREATOR与VEGA技术的虚拟场景优化技术及研究

随着虚拟现实技术的广泛应用,虚拟场景的真实感与交互的实时性已成为急待解决的一对矛盾.从提高桌面虚拟现实系统实时交互性入手,对基于软件的虚拟场景优化技术进行重点研究,使用一套基于CREATOR的技术处理流程实现了一次实验性场景优化过程,并在此基础上对过程中通过VEGA测试得到的指标参数进行详细分析,最终阐明影响场景优化效果的因素以及各因素之间的关系,指出了有效提高优化效率的方法及其原理,对于虚拟系统实时交互性的提高具有普遍意义.     

基于线索化方法的嵌入式Java虚拟机性能优化技术研究

随着计算机的不断发展，逐渐呈现出了普适计算的模式．普遍认为，Java是适应普适计算的关键技术．分析了解释运行中利用线索化方法进行性能优化的技术，实现了基于直接线索化方法的嵌入式Java虚拟机的解释器性能优化方案，并对嵌入式Java虚拟机的参考实现和基于直接线索化的优化方案进行了性能对比．     

Smart devices and spaces for pervasive computing

Applications and services for pervasive computing have been dramatically grown and have contributed extensively to our daily experiences in recent years. Smart systems, devices, and spaces are proactive for ubiquitous and pervasive computing. Smart information technology (IT) is also an outcome of the state of the art and novel mobile and ubiquitous computing technologies that include highly capable handheld device, pervasive and personal device, etc. This special issue will be a trigger for further related research and technology improvements in pervasive and ubiquitous computing using smart devices and services. This special issue called for original papers describing the latest developments, trends, and solutions of smart devices and spaces for pervasive computing including real-time operating systems (OS), tiny OS and middleware supports, mobile system performance, trustworthy Internet and communications, agents and mobile and pervasive services, among others. In particular, this special issue focuses on a remote control and media-sharing system, flash storage-based smart system, heterogeneous mobile OS, and prediction and auto-execution system for pervasive computing.     

面向普适计算环境的Android平台服务编排框架

普适计算环境下的智能移动设备是面向终端用户的服务资源聚集和编排的主要载体。普适计算环境中的服务资源具有多种不同的形态,包括基于互联网提供的Web服务、终端设备自身服务和资源(例如本地应用、自带传感器)以及所处环境中可访问的服务(例如环境传感器)。此外,不断变化的上下文环境对软件本身的自适应能力提出了新的要求,而移动设备上的服务编排受设备计算能力和资源的限制。为了解决上述问题,提出了一个面向普适计算环境的Android平台服务编排框架ASOF。通过ASOF,移动终端可在运行时获取所需业务流程的服务模板,并对该模板中的抽象服务进行服务绑定,实现轻量级的混合服务编排,使终端能够动态获得调用普适计算环境中各种类型的服务的能力。随后,基于OSGi Felix框架给出了一套ASOF的标准实现,并以一个具体案例验证其有效性。     

A resource aware software partitioning algorithm based on mobility constraints in pervasive grid environments

Pervasive computing suffers from resource limitations of mobile devices, while grid computing can utilize almost unlimited resources distributed in the whole Internet. The conjunction of such two paradigms generates a new promising one, called pervasive grid computing, where mobile users can use handheld devices to access abundant resources and services in the grid. In this paper, a novel software partitioning algorithm is presented, which is suitable for pervasive grid to optimally allocate software components between a mobile device and one or more servers, with the goal of saving the resources of mobile devices. The algorithm takes into account component mobility constraints to not only prevent violating execution requirements of the application, but also to fully exploit component mobility, replication and rebinding to conserve more resources as compared to previous works. Another distinguishing feature of the algorithm is its generality, which can be applied to minimize network bandwidth usage, response time and energy consumption, respectively or simultaneously. Extensive simulation results have demonstrated the validity and effectiveness of the proposed algorithm in various environments.     

Utility-based scheduling for grid computing under constraints of energy budget and deadline

With recent advances in computing and communication technologies enabling mobile devices more powerful, the scope of Grid computing has been broadened to include mobile and pervasive devices. Energy has become a critical resource in such devices. So, battery energy limitation is the main challenge towards enabling persistent mobile grid computing. In this paper, we address the problem of energy constrained scheduling scheme for the grid environment. There is a limited energy budget for grid applications. The paper investigates both energy minimization for mobile devices and grid utility optimization problem. We formalize energy aware scheduling using nonlinear optimization theory under constraints of energy budget and deadline. The paper also proposes distributed pricing based algorithm that is used to tradeoff energy and deadline to achieve a system wide optimization based on the preference of the grid user. The simulations reveal that the proposed energy constrained scheduling algorithms can obtain better performance than the previous approach that considers both energy consumption and deadline.     

面向移动云计算的自适应虚拟机调度算法

随着移动云计算的快速发展和应用普及,如何对移动云中心资源进行有效管理同时又降低能耗、确保资源高可用是目前移动云计算数据中心的热点问题之一.本文从CPU、内存、网络带宽和磁盘四个维度,建立了基于多目标优化的虚拟机调度模型VMSM-EUN(Virtual Machine Scheduling Model based on Energy consumption,Utility and minimum Number of servers),将最小化数据中心能耗、最大化数据中心效用以及最小化服务器数量作为调度目标.设计了基于改进粒子群的自适应参数调整的虚拟机调度算法VMSA-IPSO(Virtual Machine Scheduling Algorithm based on Improved Particle Swarm Optimization)来求解该模型.最后通过仿真实验验证了本文提出的调度算法的可行性与有效性.对比实验结果表明,本文设计的基于改进粒子群的自适应虚拟机调度算法在进行虚拟机调度时,能在降低能耗的同时提高数据中心效用.     

Scheduling and development support in the Scavenger cyber foraging system

Cyber foraging is a pervasive computing technique where small mobile devices offload resource intensive tasks to stronger computing machinery in the vicinity.One of the main challenges within cyber foraging is that it is very difficult to develop cyber foraging enabled applications. An application using cyber foraging is working with mobile, distributed and, possibly, parallel computing; fields within computer science notoriously hard for programmers to grasp.This paper presents Scavenger—a cyber foraging system supporting easy development of mobile cyber foraging applications, while still delivering efficient, mobile use of remote computing resources through the use of a custom built mobile code execution environment and a new adaptive, dual-profiling scheduler.     

Seamless mobile computing on fixed infrastructure

The term mobile computing typically evokes images of a laptop, handheld, or wearable computer. However, the plummeting cost of hardware suggests that pervasive computing infrastructure could minimize the need to carry such devices in the near future. Personal computing will be available anywhere on demand, like light at the flip of a switch. Only when a user starts to use a computer will it acquire unique customization and state. When the user finishes using the computer, this customization and state will disappear from it. Thus, a user could travel hands-free yet be confident of making productive use of slivers of free time anywhere. For this to be a compelling vision from a user's viewpoint, the customization and state acquisition process must be accurate and nearly instantaneous. For it to be a viable business model, the management and system administration costs of pervasive deployments of machines must be low. Internet Suspend/Resume is a thick-client approach to mobility in which hardware virtualization and file caching are the keys to rapid personalization of anonymous hardware for transient use.     

A collaborative face-to-face design support system based on sketching and gesturing

Mobile and pervasive computing has seen a rapid development in the last years. Portable, handheld computing devices are getting more popular as their capabilities increase. Therefore, people having the need to work on-the-field have now the possibility to be supported by computer technology, for example, garden or building designers. Ad-hoc networking capabilities of handheld devices enable the development of supporting tools for collaborative work anywhere. This paper presents MCSketcher, a system that enables face-to-face collaborative design based on sketches using handheld devices equipped for spontaneous wireless peer-to-peer networking. It is especially targeted for supporting preliminary, in-the-field work, allowing designers to exchange ideas through sketches on empty sheets or over a recently taken photograph of the object being worked on, in a brainstorming-like working style. Pen-based designed human–computer interaction is the key to supporting collaborative work. The gestures-based command input results in a lightweight yet efficient and easy to use interface. Graph structured hierarchical documents help to overcome the problems of a small screen size.     

FollowMeLite：用于普适计算的轻量级中间件平台

普适计算的目标是让环境和计算资源紧密结合，以便更好地为人类服务。为达到这一目标，移动设备和嵌入式设备构成了环境中计算资源的重要组成部分。然而，由于移动设备和嵌入式设备的计算资源有限，网络连接的多样性和不稳定性以及软硬件的异构性，开发用于这些设备的上下文感知应用复杂并且费时，其根本原因是缺乏一个统一的平台支持。为解决这一问题，我们提出了一种用于普适计算的轻量级中间件平台，叫做FollowMeLite。FollowMeLite是整个FollowMe普适计算基础结构中的一部分。它构建在OSGi之上，集成了基于本体的上下文模型和基于工作流的应用模型以及用于适应多种网络连接的通讯服务。通过部署不同的组件模块，FollowMeLite可以方便的适用于多种应用环境。     

An analytical model for delivery evaluation of multimodal contents in pervasive computing

Recent advance of mobile and interactive devices, such as smart phones, PDAs, and handheld computers, enables to deliver multimodal contents based on users and their environments. In pervasive computing, multimodal contents are mainly composed of multiple components which are often delivered from distributed multiple sources. Therefore, how appropriate contents can be provided to users and how computing resources can be effectively exploited are critical issues. In this paper, an analytical model for multimodal contents is developed based on a queueing theory for the purpose of delivery evaluation of the contents. The model can be applied to estimate how delivery parameters of multimodal contents, such as arrival rates, drop rates, and the number of packets, can impact overall the quality of services in terms of temporal aspects. A numerical example of weather information delivery is provided to illustrate the effectiveness of the proposed model.