Case of ARM emulation optimization for offloading mechanisms in Mobile Cloud Computing

The Mobile Cloud Computing (MCC) paradigm depends on efficient offloading of computation from the resource constrained mobile device to the resource rich cloud server. The computational offloading is assisted by system virtualization, application virtualization, and process state migration. However, system and application virtualization techniques force unnecessary overhead on applications that require offloading to the cloud and applications that do not. Moreover, smartphones and cloud data centers are based on heterogeneous processor architectures, such as, ARM and x86. As a result, process migrated from a smartphone needs translation or emulation on the cloud server. Therefore, instruction emulation is a necessary criterion for a comprehensive MCC framework. In this paper, we evaluate the overhead of the system and application virtualization techniques and emulation frameworks that enable MCC offloading mechanisms. We find that the overhead of system and application virtualization can be as high as 4.51% and 55.18% respectively for the SciMark benchmark. Moreover, ARM to Intel device emulation overhead can be as high as 55.53%. We provide a proof of concept of emulation speedup by utilizing efficient Single Instruction, Multiple Data (SIMD) translations. We conclude that the overhead of virtualization and emulation techniques need to be reduced for efficient MCC offloading frameworks.     

The Case for Energy-Proportional Computing

Energy-proportional designs would enable large energy savings in servers, potentially doubling their efficiency in real-life use. Achieving energy proportionality will require significant improvements in the energy usage profile of every system component, particularly the memory and disk subsystems.     

The Case for Cloud Computing

To understand clouds and cloud computing, we must first understand the two different types of clouds. The author distinguishes between clouds that provide on-demand computing instances and those that provide on-demand computing capacity.     

面向移动计算的数字水印技术研究

In the mobile computing environment, we propose a novel watermarking algorithm based on integer wavelet through pixel-wise masking with simple human visual system (HVS). Then the correlation between the watermarking sequence and the marked DWT coefficients coded with difference refinement is discussed. Finally,watermarking detection algorithm is presented for scalable coding.     

用于移动计算的软构件模型及其实现

提出了一个可上下文感知的用于移动计算环境的构件模型MCCM。首先讨论了用于移动计算环境的构件应具备的条件,然后提出了MCCM模型及其描述;接着给出了在Linux平台上的一个具体实现,并对这一实现进行了性能测试;最后同当前相关工作进行了对比,并指出了进一步的研究方向。     

The Case for Polymorphic Registers in Dataflow Computing

Heterogeneous systems are becoming increasingly popular, delivering high performance through hardware specialization. However, sequential data accesses may have a negative impact on performance. Data parallel solutions such as Polymorphic Register Files (PRFs) can potentially accelerate applications by facilitating high-speed, parallel access to performance-critical data. This article shows how PRFs can be integrated into dataflow computational platforms. Our semi-automatic, compiler-based methodology generates customized PRFs and modifies the computational kernels to efficiently exploit them. We use a separable 2D convolution case study to evaluate the impact of memory latency and bandwidth on performance compared to a state-of-the-art NVIDIA Tesla C2050 GPU. We improve the throughput up to 56.17X and show that the PRF-augmented system outperforms the GPU for \(9\times 9\) or larger mask sizes, even in bandwidth-constrained systems.     

面向移动边缘计算网络的高能效计算卸载算法

移动边缘计算（mobile edge computing,MEC）是一种高效的技术,通过将计算密集型任务从移动设备卸载到边缘服务器,使终端用户实现高带宽、低时延的目标.移动边缘计算环境下的计算卸载在减轻用户负载和增强终端计算能力等方面发挥着重要作用.考虑了服务缓存,提出一种云-边-端协同的计算卸载框架,在该框架中引入D2D （device-to-device,D2D）通信和机会网络.基于建立的模型,将计算卸载决策问题转化为一个混合整数非线性规划问题,并对无线特性和移动用户之间的非合作博弈交互制定了一个迭代机制来共同确定计算卸载方案.对提出的计算卸载算法从理论上证明了多用户计算卸载博弈模型为严格势力场博弈（exact potential game,EPG）,卸载决策可获得全网范围内的最优效益.考虑到服务器的计算资源、卸载任务数据量和任务延迟需求,提出对用户和MEC服务器之间最佳用户关联匹配算法.最后,模拟结果表明,卸载决策算法具有较快的收敛速度,并在能效方面优于其他基准算法.     

移动数据库技术和移动计算中的数据管理

移动设备和无线通信技术的快速发展,使得适应移动计算环境的新一代分布式数据库系统,即移动数据库系统迅速成为数据库领域新的研究方向。就移动数据库的基本概念和关键技术加以介绍,并介绍了几种移动计算中数据管理的机制。     

移动计算安全性

1 引言安全性问题始终是开放系统中的一个核心问题,为此,国际标准化组织ISO曾对OSI环境(开放系统环境)的安全性作过深入的研究,并为其提出了安全体系的概念集。然而,随着移动计算技术的出现和广泛的应用,许多新的安全性同题出现了,给现有的操作系统、分布式系统管理、程序设计语言和中间件技术都带     

移动云计算

智能手机、平板电脑和云计算都融合于一个新的快速增长的移动云计算领域。随着一种更移动的、钟爱设备的云环境的出现,在短短的几年时间当中,将会有1万亿云计算就绪的设备。以智能手机、平板电脑、Wi-Fi传感器为例,介绍了移动云计算平台和发展趋势。并阐述了移动云计算的关键技术,包括4G、HTML5和CSS3、虚拟机监控程序、Web 4.0等几个方面。     

一种支持脱机式计算的移动网格模型

突破了传统网格体系的思维模式,从基于请求的网格体系出发,提出了一种新的支持脱机式计算的移动网格模型,给出了模型的组织成员架构及其关系,介绍了模型的任务处理过程。该模型借用了邮递员投递挂号邮件的机制,实现了请求方主机的高度灵活性。     

移动计算中用户最优路径的选择

该文主要对移动计算中,移动用户必须同时考虑移动路径的长度和通信质量两个方面影响的问题,提出了一种基于路径长度和可变通信质量的加权综合系数的方法,选择用户移动时的最优路径,并给出了算法。     

支持移动计算的上下文感知中间件

随着移动计算和普适计算领域的不断发展,其已经对移动应用开发提出了新的挑战.与固定网络计算不同,移动计算在无线环境中运行,资源有限且环境时刻变动,应用需要感知并能适应环境变化.所以,在对上下文感知机制进行分析研究的基础上,本文提出了一个上下文感知中间件体系结构.     

移动边缘计算中的协同计算卸载策略

针对单边缘服务器卸载时导致异地边缘服务器空闲状态下资源浪费问题,在远程云与多个边缘服务器联合卸载的方案下,提出一种基于改进混合粒子群算法的边缘云协同计算卸载策略（cross reorganization PSO,CRPSO）。该卸载策略中以最小化系统总代价（时延和能耗的加权和）为目标建立模型,在粒子群算法中利用适应度对粒子进行优劣分组,通过引入遗传算法中的交叉思想对劣势组的粒子进行取优,由两层筛选机制优化原始种群中粒子,经过算法迭代实现任务的最优卸载策略。仿真结果表明,与Local-MEC算法、ECPSO算法和GCPSO算法相比,所提出的CRPSO算法的系统总代价最小,优化效果明显。     

移动操作SoC接口IP组件设计

移动操作或移动计算（mobile computing）是嵌入式系统研究的一个重要方向。为移动操作设计的SoC（System on a Chip）g具有理论意义，更拥有实际应用的价值。和任何SoC的设计一样，移动操作SoC也需要设计各种相应的IP组件。本文描述了采用可编程器件进行移动操作SoC外部接口IP组件设计的方法，并以外部数据存储器控制为例，进行基于PLD的IP设计。仿真结果显示该设计是成功的，相应移动操作SoC的IP组件的操控运行有效、快速。     

交互感知应用微云服务框架

当前,开发使用微云服务的交互感知应用时存在开发困难以及重复开发的问题.为解决这些问题,设计并实现了为交互感知应用提供微云服务的框架Bolt.Bolt服务框架以ZeroMQ消息处理队列为基础,分为三部分：Bolt Client Lib库、Bolt Service Lib库以及Bolt Broker代理,构成“Client-Broker-Service”的三级架构.Bolt Client Lib和Bolt Service Lib分别为移动端应用和微云端处理引擎分别提供API,使应用与处理引擎的开发得以分离,降低了开发难度并减少重复开发的情况.实验结果表明,与Gabriel等应用相比,Bolt服务框架使用的通信端口降低到2个,同时,将系统开销降低到1ms左右的时间.     

Applying Coordination for Service Adaptation in Mobile Computing

Mobile computing devices vary in terms of display, memory, and battery life, and current network protocols aren’t necessarily suited to the mobile computing environment. As computer networks' complexity increases, communication-related software must be able to adapt to mobile computing’s constraints. This study aims to develop a software system that adapts data flows over dynamic wireless network conditions and various mobile devices. With their MobiGATE system, the authors adopt the principle of separation of concerns to support the system's service composition and reconfiguration. This approach can support ease of dynamic reconfiguration and the reusability of adaptation services across applications.     

移动教育

移动计算被认为是对未来发展有最有影响的技术之一,文章探讨了移动计算对未来教育的影响,提出了未来教育的模式———移动教育的概念,并且分析了移动教育的特点,研究了移动教育的教育理论基础,探讨了移动教育的必然性。