基于boa的嵌入式视频监控系统的研究与实现

本文介绍了一种基于BOA网络服务器的嵌入式视频监控系统设计与实现,首先主要阐述了该系统的整体结构及工作流程,及其主要将要实现的功能模块,然后针对系统下两大模块BOA web服务器模块和云台控制与预置位模块分别进行了较为详细的介绍,分别介绍了BOA网络服务器实现原理、工作流程,以及移植到嵌入式系统;云台控制与预置位模块的设计及其工作流程实现。该系统设计方案融合了嵌入式技术网络技术,功能可靠完善,性能与传统视频监控系统相比具有较大的优势,能够很好的应用在视频监控中,具有重要的实际应用价值。     

基于服务器虚拟化的智慧云桌面系统设计与应用

针对传统桌面环境硬件资源利用率低且多元化分配效果差等特点,设计出一种基于服务器虚拟化技术和FFmpeg音视频处理技术相结合的智慧云桌面系统。该系统的设计初衷是将互联网与高校教学办公相结合,实现校园内智慧云办公和线上直播教学等功能。系统通过Proxmox VE虚拟化环境搭建后台服务器,采用FFmpeg作为音视频数据处理的技术框架,并通过对框架的优化,缩短了直播教学中的延迟。最后,通过测试证明云桌面系统能够有效地缓解传统桌面在资源管理和设备成本等方面的问题,其线上直播教学模块的播放延迟能够控制在100 毫秒以下,提高了校园环境下的协同办公、直播教学以及实验室信息化建设的便捷性和实用性。     

半分布式P2P Botnet控制服务器的设计与实现

控制服务器是半分布式P2P Botnet的bot程序最为重要的核心部分.基于Socket非阻塞模式的select模型,设计并实现了半分布式P2P Botnet的控制服务器.详细介绍了控制服务器的主要功能模块及各模块之间的运行关系,阐述了控制服务器的工作流程及相关的关键数据结构.从僵尸网络的资源占用、传递速度和控制方式等方面,与传统的IRC Botnet、全分布式P2P Botnet做了比较.实验结果表明,开发的控制服务器不管是功能还是性能,均满足半分布式P2P Botnet的要求.     

浅谈《数据结构》课程在线考试系统的开发

该文分析了在线考试系统的设计与实现技术,通过采用基于WEB的思想,为解决实际需求对系统的整体结构进行设计,并设置了相应的功能模块。本系统主要分为三个模块:管理员模块、教师模块和学生模块。管理员模块包括学生资料管理、题库管理、试卷管理和科目管理四个子功能模块。学生模块主要包括参加考试和考试查询两个子功能模块。教师模块主要包括在线阅卷的功能。     

基于Android平台的移动图书馆客户端设计与实现

在智能手机软件不断发展的今天,很多传统PC机上的应用正在向智能手机客户端转移。基于Android平台和智能手机的移动图书馆系统实现了客户端与服务器的通讯,使得用户可以通过手机客户端访问和查询各类图书信息。设计了系统框架及功能模块,描述通过无线通信实现客户端与服务器间的通讯的方法,并列出主要模块的实现算法。     

基于MPEG4硬件编码的视频监控系统的实现

本文介绍了基于Faraday公司FA526处理器和硬件编解码器FMTCP100的网络视频监控系统的设计与实现.文章详述了实时网络视频监控服务器的系统框架和各功能模块的软硬件设计和实现,包括视频采集模块、视频编码模块和视频传榆模块等.由于充分利用了已有的开源项目,简化了系统的复杂性,并使得该方案具有良好的可移植性.     

基于Android平台的移动图书馆客户端设计与实现

在智能手机软件不断发展的今天,很多传统PC机上的应用正在向智能手机客户端转移.基于Android平台和智能手机的移动图书馆系统实现了客户端与服务器的通讯,使得用户可以通过手机客户端访问和查询各类图书信息.设计了系统框架及功能模块,描述通过无线通信实现客户端与服务器间的通讯的方法,并列出主要模块的实现算法.     

在线油烟实时监测系统的设计与实现

为了解决传统油烟检测方法中成本高、效率低、实时性差等问题,设计开发了一种在线油烟实时监测系统。系统由采集、通讯、服务器和用户交互四个模块组成。采集模块采集油烟数据,通过GPRS通讯技术将数据发送至服务器。数据在服务器中按照解码规则进行解码后,存入数据库。通讯模块采用MINA框架进行开发,服务器模块采用SSM框架开发。用户交互模块为B/S模式,用户登陆监测网站访问服务器。服务器提供实时数据、历史数据和超标数据查询等功能,极大的方便了相关部门对油烟排放的监督与管理,提高了监测中心工作效率和服务质量。     

电子产线实践平台远程监测系统设计

基于高校实验室对电子产线实践平台工作状态的监测需求,设计了一套低成本、高稳定性的远程监测系统。该系统应用云技术将底层视频传输模块、平台监测模块、移动应用模块整合一体。平台监测模块使用工控机采集运行状态数据发送到云平台,通过摄像头二次开发功能获取视频图像。云服务器为电子产线实践平台和安卓App提供数据服务,安卓App监测电子产线实践平台的运行状态信息,实现现场电气设备的远程控制。利用云服务器的存储功能实现状态浏览、权限管理等功能。工控机与服务器中使用Mina框架实现网络长连接,保证电子装配实践平台中运行状态的网络传输。经过测试,用户可以通过远程监测系统实现对该平台的控制。系统能够降低二次开发和维护的成本,满足智慧实验室的建设需求。     

基于FPSLIC的网络家居终端系统的设计与实现

为了对家居进行远程智能控制和管理,实现家居的实时监控,以无线收发数据和控制为主要技术,设计和实现了一个基于FPSLIC主控芯片的网络家居终端系统.系统包括：中央控制器模块、家居安防模块、家居电器信息化模块和远程服务器控制模块4大功能模块.通过用户远程网络登陆来实时监控家居的安防情况,同时实现用户新旧家居的信息化改造,并提供社区内的信息化服务平台,可以将单个用户终端系统扩展组成小区范围的综合家居智能控制和管理系统.     

一种新的直播服务器实现框架

提出了一种新颖的直播服务器构架，在服务器中采用轮询式处理模式，并以RTP、RTSP和UDP协议为基础构造协议栈。在此基础上从两个方面考虑提高直播服务器的性能：在服务器中应用简单的平滑策略以平滑数据的发送过程，增加直播服务器的并发数；以音频数据的发送时间为基准进行媒体数据的发送，以增加服务器对视频流帧率波动的适应性。所提出的直播服务器实现框架和提高服务器性能的措施对于开发直播服务器的实践活动具有参考意义。     

Peer Assisted Video Streaming With Supply-Demand-Based Cache Optimization

In this paper, we consider a hybrid P2P video on-demand architecture that utilizes both the server and the peer resources for efficient transmission of popular videos. In our system architecture, each peer dedicates some cache space to store a particular segment of a video file as well as some of its upload bandwidth to serve the cached segment to other peers. Peers join the system and issue a streaming request to a control server. Control server directs the peers to streaming servers or to other peers who have the desired video segments. Control server also decides which peer should cache which video segment. Our main contribution in this paper is to determine the proper caching strategies at peers such that we minimize the average load on the streaming servers.      

基于服务质量保证的流媒体服务器设计

针对视频直播系统的特性、不稳定的Internet网络环境,重点研究了流媒体服务器服务质量保证措施,设计并实现了一种基于可扩展编码的视频直播流媒体服务器软件系统.该系统提供网络环境自适应的具有一定QoS保证的视频传输服务,已应用于国内大型通信公司.实际运行结果表明该系统提高了数据传送率,降低了网络延迟.     

Improving the virtualization of rich applications by combining VNC and streaming protocols at the hypervisor layer

Virtual desktop infrastructure (VDI) solutions seek to provide a satisfactory user experience at the client side when accessing remote desktop applications, even from mobile devices with limited capabilities. This paper presents a new approach, improving on previous work by the authors, in which a combination of Virtual Network Computing (VNC) and streaming protocols allowed efficient remote web access to virtualized applications within a cloud architecture. The new approach simplifies virtual machine templates, from which virtual machine instances are deployed, by centralizing software modules, greatly simplifying their management. Our new contribution consists of an integrated solution with specific WebM video encoding modules in charge of application visual output processing, an Hypertext Transfer Protocol (HTTP) streaming server, and a VNC server. The solution can be installed in the hypervisor of the host machines instead of replicating the servers and modules throughout the guest (virtual) machines that run the virtualized applications. Consequently, their implementations are unique and independent of the operating system of the virtual machines. In short, it is not necessary to provide different implementations for different operating systems, which reduces the complexity of virtual machine templates and greatly simplies platform management. To demonstrate our solution, we have modified the Quick Emulator (QEMU)‐Kernel‐based Virtual Machine (KVM) hypervisor source code accordingly. We also present qualitative and quantitative analyses that demonstrate that the new approach is advantageous in terms of software management and quality of experience, compared with our previous work and other well‐known thin clients, contributing to the enhancement of VDI systems. Copyright © 2015 John Wiley & Sons, Ltd.     

Robust control in cloud assisted peer to peer live streaming systems

Existing live video streaming systems can be classified as server (cloud) based or as peer-to-peer (P2P). The client–server approach promises stability and (Quality of Service) QoS by incurring expensive bandwidth provision cost on the server. On the other hand, P2P architecture is scalable with low bandwidth and maintenance cost. Here we propose a cloud assisted P2P live streaming architecture which is scalable and stable. In order to achieve this we have developed: (i) a scalable gossip protocol that monitors dynamically the total available bandwidth resources of the participating peers, (ii) a control strategy that dynamically allocates the bandwidth that is required.The first step towards this direction is to create a theoretical model that captures the dynamic relationship between the total bandwidth surplus/deficit and peers’ bandwidth utilization in order to be able to apply a control theoretical approach. Moreover, we quantify the impact of monitoring inaccuracies and peers’ dynamic bandwidth changes and we calculate analytically, as a function of them, the minimum amount of bandwidth overprovision that ensures the undisturbed distribution of the stream. System is evaluated through a detailed simulator of a complete P2P live streaming system and testified the uninterrupted and complete stream delivery even in very adverse bandwidth changes.     

Enabling broadcast of user-generated live video without servers

We are witnessing the unprecedented popularity of User-Generated-Content (UGC) on the Internet. While YouTube hosts pre-recorded video clips, in near future, we expect to see the emergence of User-Generated Live Video, for which any user can create its own temporary live video channel from a webcam or a hand-held wireless device. Hosting a large number of UG live channels on commercial servers can be very expensive. Server-based solutions also involve various economic, copyright and content control issues between users and the companies hosting their content. In this paper, leveraging on the recent success of P2P video streaming, we study the strategies for end users to directly broadcast their own live channels to a large number of audiences without resorting to any server support. The key challenge is that end users are normally bandwidth constrained and can barely send out one complete video stream to the rest of the world. Existing P2P streaming solutions cannot maintain a high level of user Quality-of-Experience (QoE) with such a highly constrained video source. We propose a novel Layered P2P Streaming (LPS) architecture, to address this challenge. LPS introduces playback delay differentiation and constructs virtual servers out of peers to boost end users’ capability of driving large-scale video streaming. Through detailed packet-level simulations and PlanetLab experiments, we show that LPS enables a source with upload bandwidth slightly higher than the video streaming rate to stream video to tens of thousands of peers with premium quality of experience.     

面向服务的线程控制模型研究

为了满足飞速发展的Intemet对服务器性能的要求,由多台服务器构成服务器集群系统来分担负荷已成为实现高可伸缩的、高可用网络服务的有效结构。目前的服务器集群系统大多集中在对服务器（包括虚拟服务器和真实服务器）进行改进或扩展上,而没有考虑对socket协议本身进行扩展,本文提出了一个新的面向服务的线程控制模型,通过对文件系统调用的修改,扩展socket协议,构建了支持集群的服务器集群系统,取得了良好的性能改进。     

MOWS: distributed Web and cache server in Java

In this paper, a distributed Web and cache server called MOWS is described. MOWS is written in Java and built from modules that can be loaded locally or remotely. These modules implement various features of Web and cache servers and enable MOWS to run as a cluster of distributed Web servers. In addition to its distributed nature, MOWS can integrate external services using its own external interface. Java programs conforming to this interface can be loaded locally or remotely and executed at the server. The resulting system will potentially provide effective Web access by both utilizing commonly available computing resources and offering distributed server functionality. Design considerations and the system architecture of MOWS are described and several applications of MOWS are described to show the benefits of MOWS.     

Optimizing content placement in a peer-assisted VoD architecture

Recently, a new peer-assisted architecture to build content delivery systems has been presented. This architecture is based on the use of the storage capacity of end-users’ set-top boxes (STBs), connected in a peer-to-peer (P2P) manner in order to help the content servers in the delivery process. In these systems, the contents are usually split into a set of smaller pieces, called sub-streams, which are randomly injected at the STBs. The present paper is focused on Video on Demand (VoD) streaming and it is assumed that the STB-based content delivery system is deployed over the global Internet, where the clients are distributed over different ISP networks. In this scenario, three different strategies are studied for increasing the percentage of data uploaded by peers, in order to offload the content servers as much as possible. First of all, a new mechanism is presented which determines which sub-stream has to be placed at which STB by a Non-Linear Programming (NLP) formulation. A different strategy for reducing the content server load is to take advantage of the available bandwidth in the different ISP networks. In this sense, two new mechanisms for forwarding the VoD requests to different ISP networks are presented. Finally, the present paper also shows that in some situations the available uplink bandwidth is associated with STBs that do not have the required sub-streams. Regarding this concern, a new mechanism has been designed that dynamically re-allocates some streams, which are being transmitted from specific STBs, to different STBs, in order to find the necessary resources to start new streaming sessions.     

多形态流媒体服务系统控制信令的研究与设计

针对现有视频监控联网系统中传统流媒体服务器存在的问题,提出了一种多形态流媒体服务系统.其中,将功能整合的传统媒体服务器架构进行拆分,降低了各模块耦合性,使系统具有易扩展、高稳定的特点.基于此架构,本文对系统所使用的控制信令进行了研究与设计.实验结果表明可负载均衡、动态扩展的新架构和连通新架构的控制信令的使用可以进一步提高多形态流媒体服务系统的稳定性、可管理性.