基于SOA的云计算框架研究

互联网发展速度极快,信息数据量也呈现爆炸式增长的趋势,云计算是一种全新的计算机模式,受到了广泛的关注和应用。云计算平台和云计算框架是目前云计算研究的两大主要对象,SOA体系结构具有先进的松散耦合和集成服务的理念,是云计算机应用的一种可行途径。     

基于自适应的软件定义安全架构

随着云计算的快速发展,传统固定边界和设备的安全手段,在云安全时代出现了技术上的不适应以及疲于奔命的运维现象。“软件定义”适用于解决云计算中面临的系统性问题。软件定义安全有轻量、易部署、高兼容、可编排的特点,结合Gartner提出的自适应安全架构的思想,设计了可以自适应的软件定义安全的架构。该架构可以分为管理编排层、控制层、业务层和物理层,以松耦合的模块结合形式,开放标准对外接口,兼容新技术的使用和对接,实现虚拟安全网元自动可编排的自适应安全闭环。     

利用自适应实时DSP架构优化电网

过去几十年来，电源系统呈指数式增长，其非线性特性引起了严重的谐波污染，这可能带来多方面的不利影响，例如，电气设备过热和过早老化，传输线路损耗增加，以及继电器保护失灵等。因此，业界越来越关注谐波污染问题，并采取了各项措施以实现更好的电网管理。其中，最佳的一个方法是在电网内设置更多的观测和分析点，并且延长监控时间。随着智能电表在全世界范围内的加快部署，满足上述要求的最佳器件可能通过其来实现。     

基于MVC模式的Tapestry框架研究与应用

首先分析了当前Web应用界面开发中存在的一些问题,重点介绍一种开源的基于MVC架构的表现层开发框架Tapestry,给出了Tapestry的功能架构以及相应的实例说明,最后总结了使用Tapestry框架开发Web系统的优缺点。     

基于提升框架的一种自适应滤波方法研究

Haar小波和CDF(2,2)小波都可用提升框架的形式表示,该文把它们与无更新算子的Haar小波有机结合到一起,形成了自适应小波变换,随着信号的变化可以自动地选择合适的小波基。仿真结果表明,自适应小波变换对于含噪声的突变信号和光滑信号都有良好的去噪性能,兼具了Haar小波和CDF(2,2)小波各自的优点,适用范围更宽。     

基于数据分析的云安全体系架构研究

针对云计算安全体系架构的不完备性,文章提出基于数据分析的云安全体系模型,同时以解决云安全体系评估数据来源的不准确问题,提出基于自适应的云安全评估方法,从而构建完备的云安全体系架构。     

基于内容自适应的实时视频水印算法研究

设计了一种基于内容自适应的实时视频水印算法。该算法使用Arnold变换对原始水印图像进行置乱,能够基于视频内容自适应地将水印图像嵌入到原始视频的每一帧中,且实现了水印图像的盲提取。实验结果表明,该算法具有实时性、不可感知性,对高斯噪声、Speckle及帧裁剪等常规攻击具有较好的稳健性,可以作为一种防插播、防篡改技术应用于数字广播电视领域中。     

基于FPGA的实时图像自适应中值滤波器设计

利用自适应的中值滤波算法,设计了基于FPGA的实时图像自适应中值滤波器。与之前的软件实现方法相比,程序能满足实时性的要求,且占用资源少,是一种简单易行的方案。在Xilinx硬件平台上已经得到验证。     

基于自适应匹配的实时视频拼接系统

为了实现基于PC机的实时视频拼接,提出一种基于自适应匹配的平移参数计算方法。设计基于海思HI3520D开发平台采集两路视频,UDP传输视频,PC机接收视频并实现视频拼接。在系统启动时候,通过巴氏距离方法得到融合后的图像重叠区域匹配度,反馈优化,得到最佳平移参数。试验证明该系统不仅提高了图像融合质量而且具有良好的实时性,实现了两路视频实时拼接,系统总体拼接速度为40ms左右。     

Linux的实时性能测试

本文首先分析了常用的实时性能的测试指标，然后深入分析了在Linux中有哪些因素影响了这些实时性能指标，介绍了常用的实时化方法以及测试方法，最后对这些的方法的实时性能进行了测试。     

Framework for CORBA Extensions to Support Real-Time Object-Oriented Applications

Object-oriented distributed real-time applications require enforcement of end-to-end timing constraints on service requests from clients to servers. Thus, timing aspects should be integrated and handled by CORBA which is a standard to support distributed object-oriented applications. In spite of the release of real-time CORBA (RT-CORBA) specification, a few vendors have ported their ORBs (Object Request Brokers) to real-time operating systems. In this paper we analyze existing RT-CORBA implementations, and we propose a framework that integrates the main components (scheduling, real-time communication, end-to-end quality of service providing, etc.) necessary for implementation of RT-CORBA to support static and dynamic real-time applications.     

利用软集成设计实时网络程序框架

文章设计并实现了多线程网络通信程序平台,该平台提供了一个能够满足各种网络传输协议和格式的网络程序框架,程序框架采用了网络协议的实现与数据处理的实现相分离的结构,每一个网络连接对应一个独立线程,在框架的支持下同步运行.每一个连接线程都带有独立的数据缓冲区,缓冲区的大小可以随时进行调整.框架中的功能均能够在运行期间被停止或...     

Analytical Models for Architecture-Based Software Reliability Prediction: A Unification Framework

Traditional approaches to software reliability modeling are black box-based; that is, the software system is considered as a whole, and only its interactions with the outside world are modeled without looking into its internal structure. The black box approach is adequate to characterize the reliability of monolithic, custom, built-to-specification software applications. However, with the widespread use of object oriented systems design & development, the use of component-based software development is on the rise. Software systems are developed in a heterogeneous (multiple teams in different environments) fashion, and hence it may be inappropriate to model the overall failure process of such systems using one of the several software reliability growth models (black box approach). Predicting the reliability of a software system based on its architecture, and the failure behavior of its components, is thus essential. Most of the research efforts in predicting the reliability of a software system based on its architecture have been focused on developing analytical or state-based models. However, the development of state-based models has been mostly ad hoc with little or no effort devoted towards establishing a unifying framework which compares & contrasts these models. Also, to the best of our knowledge, no attempt has been made to offer an insight into how these models might be applied to real software applications. This paper proposes a unifying framework for state-based models for architecture-based software reliability prediction. The state-based models we consider are the ones in which application architecture is represented either as a discrete time Markov chain (DTMC), or a continuous time Markov chain (CTMC). We illustrate the DTMC-based, and CTMC-based models using examples. A detailed discussion of how the parameters of each model may be estimated, and the life cycle phases when the model may be applied is also provided     

An Adaptive Heterogeneous Runtime Framework for Irregular Applications

Future computing devices are likely to be based on heterogeneous architectures, which comprise of multi-core CPUs accompanied with GPU or special purpose accelerators. A challenging issue for such devices is how to effectively manage the resources to achieve high efficiency and low energy consumption. With multiple new programming models and advanced framework support for heterogeneous computing, we have seen many regular applications benefit greatly from heterogeneous systems. However, migrating the success of heterogeneous computing to irregulars remains a challenge. An irregular program's attribute may vary during execution and are often unpredictable, making it difficult to allocate heterogeneous resources to achieve the highest efficiency. Moreover, the irregularity in applications may cause control flow divergence, load imbalance and low efficiency in parallel execution. To resolve these issues, we studied and proposed phase guided dynamic work partitioning, a light-weight and fast analysis technique, to collect information during program phases at runtime in order to guide work partitioning in subsequent phases for more efficient work dispatching on heterogeneous systems. We implemented an adaptive Runtime System based on the aforementioned technique and take Ray-Tracing to explore the performance potential of dynamic work distribution techniques in our framework. The experiments have shown that the performance gain of this approach can be as high as 5 times faster than the original system. The proposed techniques can be applied to other irregular applications with similar properties.     

Intelligent Monitoring for Adaptation in Grid Applications

Grid applications access distributed, and often shared, resources. One consequence of this resource sharing is that measured application performance can vary widely and in unexpected ways. Determining the causes of poor performance, due to either anomalous application behavior or contention for shared resource use, and adapting to changing circumstances are critical to creation of robust Grid applications. Performance contracts and real-time adaptive control are two mechanisms to realize soft performance guarantees in Grid environments. Performance contracts formalize the relationship between application performance needs and resource capabilities. During execution, contract monitors use performance data to verify that expectations are met. When the contracted specifications are not satisfied, the system can choose to either adapt the application to available resources or reschedule the application on a new set of resources that can satisfy the original contract specifications. We describe an infrastructure for Grid application contract development and monitoring. This infrastructure, based on the Autopilot toolkit, provides flexible and scalable tools to assess both application and system behavior.     

基于实时传输协议的多媒体应用框架设计

当前的网络环境下，在Windows平台上多媒体应用的开发结构复杂，并且可扩展性差，易用性不高。针对此特点，介绍了流媒体传输的基本协议RTP／RTCP，分析了RTP协议中的负载类型和当前基于实时传输协议（RTP）的多媒体应用的特点和结构，采用大型软件流行的架构方法，为多媒体应用开发构建了一个基本框架，充分考虑了将来扩展的需求和易用性，并给出一个实例，说明了实例的应用效果，证明了设计的框架是可行的，最后讨论了一些不足和将来的趋势。     

Packet Encryption for Securing Real-Time Mobile Cloud Applications

Mobile Networks and Applications - The evolution of smart devices has brought the most confidential data to mobile applications and cloud computing with its processing power is serving the huge...     

CAVLC Encoder Design for Real-Time Mobile Video Applications

This brief presents a new context-based adaptive variable length coding (CAVLC) architecture. The prototype is designed for the H.264/AVC baseline profile entropy coder. The proposed design offers area savings by reducing the size of the statistic buffer. The arithmetic table elimination technique further reduces the area. The split VLC tables simplify the process of bit-stream generation and also help in reducing some area. The proposed architecture is implemented on Xilinx Virtex II field-programmable gate array (2v3000fg676-4). Simulation result shows that the architecture is capable of processing common/quarter-common intermediate format frame sequences in real-time at a core speed of 50 MHz with 6.85-K logic gates.     

基于PC架构交互式电视机顶盒的性能分析

本文介绍交互式电视系统,分析交互式电视机顶盒的应用、结构,并结合实验室对交互式电视机顶盒的测试经验,重点探讨基于PC平台的交互式电视机顶盒的测试方法、途径和应该测试的项目.