Contextual usage patterns in smartphone communication services

The mobile end user context has received a lot of attention from the mobile services industry lately. The location-based and context-sensitive information that are characteristic for smartphones can be utilized to study the use context of mobile end users. Accordingly, this article utilizes handset-based data in analyzing how the context of use affects the usage of smartphone communication services. The context is identified with an algorithm utilizing mobile network cell ID and WLAN data and resulting in five place-related contexts, namely Home, Office, Other meaningful, Elsewhere and Abroad. According to our analysis, voice calls are used least intensively in the Home context where the length of the voice calls is the longest, however. Email and SMS are used most intensively in the Office context, where the voice calls are the shortest in duration. Finally, mobile IM/VoIP and social media services are more free-time oriented as they are used most intensively in Elsewhere and Other meaningful contexts. The findings imply that people use smartphone communication services differently depending on the use context. However, context can be defined and identified in a number of ways, and this article presents only one solution that is highly dependent on the type of data collected.     

移动远程视频监控系统

为了扩大单个摄像头的视频监控范围及灵活性, 设计了一种可远程操控的移动视频监控系统. 该系统由四个模块组成, 基于Arduino系统的智能车搭载有摄像头, 接收用户指令, 用于移动视频的采集; 嵌入式Linux系统通过V4L2接口实现对视频数据的实时采集, 一方面将数据通过网络发送至转发服务器, 另一方面将来自用户的控制指令转发至智能车; 服务器则用于转发视频至客户端以及转发用户控制指令至Linux系统; 基于Android的移动端呈现监控视频并提供用户控制界面. 与现有系统相比, 该系统可使用单摄像头实现无死角监控.     

基于VC的变电站视频监控系统控制软件设计

针对现今无人值守与远程监控的要求，本文研究了基于网络的远程视频监控系统。本系统申前端多个监控点，远程视频服务器，客户端监控中心和通信网络构成。在视频压缩上采用适应能力强的H.263协议，减少网络数据流量，以便多路数据的同时传递，通信采用光纤网络，可根据需要采用TCP／IP或者UDP协议进行网络传输，实际中投入变电站无人值守管理使用，也可以用于其他无人值守现场。     

User interface and interactivity display for converging PC,IPTV, and mobile device in a video sharing service

This paper proposes a user interface and interactivity adaptor for PCs, Internet protocol televisions (IPTVs), and mobile devices. The adaptor accounts for the screen limitations for display of mobile devices and the remote control limitations for the interactivity of IPTVs. A framework for convergence of these client‐side devices is also proposed as a basis for a video sharing service. In‐depth verification and evaluation demonstrate the robustness of the proposed adaptor.     

Utilizing a Bluetooth remote lock system for a smartphone

With the advent of mobile devices and the convergence of wireless technologies and the Internet, both the content and the quality of research in this field are subject to regular change. A variety of state-of-the-art computing devices that are compatible with each other have been produced. These devices have the ability to interact with people. This is also known as pervasive computing. Particularly, as smartphones have recently become one of the most popular devices worldwide, various convenient applications are being released. Smartphones available today not only provide the ordinary internal processes such as dialing or receiving phone calls, sending text messages, and doing mobile banking, but also increasingly control various other devices that are part of our daily lives. In effect, this means that through smartphone applications, we can remotely control a variety of external devices such as televisions, projectors for presentations, computers, and even cars. The research in this paper is based on the evolving technological possibilities of using smartphone applications to control external devices. This paper presents the design and implementation of a remote lock system using wireless communication on a smartphone. In this context, remote lock system refers to a lock system that can be controlled remotely by a dedicated Android application. Every smartphone is equipped with Bluetooth which makes this technology possible. The application proposed in this paper uses the existing Bluetooth function on Android smartphones to open and manage locks. The users’ lock information can be stored and managed in real time in the database via a server that is built and managed by a server manager. Even if users forget the password of the lock, our proposed lock system can guide them to retrieve it easily, and a user manual is included to help users navigate the system. This system also provides a variety of management functions such as adding, deleting, modifying, and purchasing the user’s own locks.     

Picture browsing non-touch interaction methods for smartphones using an accelerometer and camera with a focus on phone dialing

This paper proposes various interaction methods for smartphones that allow users to call an intended contact without touching the smartphone screen. Existing applications allow users to answer phone calls without touching the screen—by shaking the phone, for example—but do not allow users to make phone calls. The proposed interaction allows users to select and call an intended contact by utilizing the iPhone’s accelerometer. The interaction also involves video camera scanning for commands to switch between group-selection and individual-selection modes to facilitate the selection of the call candidate. Furthermore, the proposed interaction secures transparency by displaying the camera’s video stream on the smartphone screen. In order to evaluate the efficacy of the interaction, an application using the interaction was developed, and two simple experiments were conducted, in which participants were asked to make phone calls using the application. The success rate was 98 %, and user satisfaction with the proposed interaction was approximately 90 %. Therefore, the results showed that the proposed interaction could be an effective solution to allow users to make phone calls in situations where they cannot physically touch the iPhone screen. Furthermore, this solution could be used in many fields that need interactions with users in mobile applications.     

Teleoperation User Interfaces for Mining Robotics

This paper presents a brief discussion of the requirements for user interfaces for teleoperation of mining vehicles and systems. Current commercial interfaces are relatively simple, evolving from line-of-sight remote control systems with the addition of video displays. This level of sophistication has nonetheless allowed teleoperation to be a viable and profitable technique. CSIRO Exploration and Mining research into interface design currently concentrates on fusion of non-visual feedback to the operator and efficient presentation of such information. Case studies based on user interfaces for two experimental teleoperated mining-related systems, the Numbat mine emergency response vehicle and remote highwall mining control systems are described. In both cases the purpose of the user interface is to satisfy the major client requirements for mining systems of robustness, reliability and ease of use by site operational and support personnel.     

基于Android 的移动视频监控系统的设计

本文将采用全新的信息技术设计出满足用户需求的移动视频监控系统。该移动视频监控系统集中运用了 AI2 编程技术、H.264 视频压缩编码技术、网络传输技术、SAE云计算技术等。该系统具有移动视频在线点播和移动视频在线 采集功能,管理员可应用Windows 客户端管理网络服务器的用户信息和视频数据。     

Analysis of Skype VoIP traffic in UMTS: End-to-end QoS and QoE measurements

In the future Internet, multi-network services will follow a new paradigm in which the intelligence of the network control is gradually moved to the edge of the network. This impacts both the objective Quality of Service (QoS) of the end-to-end connection as well as the subjective Quality of Experience (QoE) as perceived by the end user. Skype already offers such a multi-network Voice-over-IP (VoIP) telephony service today. Due to its ease of use and a high sound quality, it becomes increasingly popular in the wired Internet.UMTS operators promise to offer large data rates which should suffice to support VoIP calls in a mobile environment. However, the success of those applications strongly depends on the corresponding QoE. In this work, we analyze the theoretically achievable as well as the actually achieved quality of IP-based voice calls using Skype. This is done performing measurements in both a real UMTS network and a testbed environment. The latter is used to emulate rate control mechanisms and changing system conditions of UMTS networks. The results show in how far Skype over UMTS is able to keep pace with existing mobile telephony systems and how it reacts to different network characteristics. The investigated performance measures comprise the QoE in terms of the MOS value and the QoS in terms of network-based factors like throughput, packet interarrival times, or packet loss.     

基于B/S结构的智能家居远程巡警监控系统的设计

针对现代办公、室内家居监控多目标的问题,结合ZigBee无线传输技术、智能车控制技术,构建了以B/S模式为基础的Web服务器,设计了一种新的远程巡警监控系统。采用KB-204数字视频监控录像采集卡,前端视频服务器配以花生壳的动态域名,实现系统的远程视频监视;以OURS-IOTV2物联网创新实验套件为开发平台,运用Html、JDBC技术构建Web服务器,实现客户端用户只需使用IE浏览器便能完成对家居移动小车的远程运动控制,同时在移动小车上装有BH9402热释电红外传感模块,当模块检测出异常信号时,会在客户端浏览网页界面上即时显示"室内有人"等信息。     

Adaptive interface selection over cloud-based split-layer video streaming via multi-wireless networks

As mobile devices such as tablet PCs and smartphones proliferate, the online video consumption over a wireless network has been accelerated. From this phenomenon, there are several challenges to provide the video streaming service more efficiently and stably in the heterogeneous mobile environment. In order to guarantee the QoS of real-time HD video services, the steady and reliable wireless mesh is necessary. Furthermore, the video service providers have to maintain the QoS by provisioning streaming servers to respond the clients’ request of different video resolution. In this paper, we propose a reliable cloud-based video delivery scheme with the split-layer SVC encoding and real-time adaptive multi-interface selection over LTE and WiFi links. A split-layer video streaming can effectively scale to manage the required channels on each layer of various client connections. Moreover, split-layer SVC model brings streaming service providers a remarkable opportunity to stream video over multiple interfaces (e.g. WiFi, LTE, etc.) with a separate controlling based on their network status. Through the adaptive interface selection, the proposed system aims to ensure the maximizing video quality which the bandwidth of LTE/WiFi accommodates. In addition, the system offers cost-effective streaming to mobile clients by saving the LTE data consumption. In our system, an adaptive interface selection is developed with two different algorithms, such as INSTANT and EWMA methods. We implemented a prototype of mobile client based on iOS particularly by using iPhone5S. Moreover, we also employ the split-layer SVC encodes in streaming server-side as the add-on module to SVC reference encoding tool in a virtualized environment of KVM hypervisor. We evaluated the proposed system in an emulated and a real-world heterogeneous wireless network environments. The results show that the proposed system not only achieves to guarantee the highest quality of video frames via WiFi and LTE simultaneous connection, but also efficiently saves LTE bandwidth consumption for cost-effectiveness to client-side. Our proposed method provides the highest video quality without deadline misses, while it consumes 50.6% LTE bandwidth of ‘LTE-only’ method and 72.8% of the conventional (non-split) SVC streaming over a real-world mobile environment.     

Will mobile video become the killer application for 3G mobile Internet? a model of media convergence acceptance

We propose and empirically test a model of user acceptance of digital media convergence. Integrating information system research, particularly the paradigm of task–technology fit and the platform–application dichotomy, and theories from media psychology and human–computer interaction, we theorize the fit between the content applications and the media platform as the key determinant of user evaluation and acceptance of digital media convergence. We empirically tested our theory in the context of mobile video entertainment services. Specifically, we hypothesize that both the duration of the video content (i.e., the characteristic of the content) and the attentional constraint of the mobile media platform (i.e., the characteristic of the media platform) jointly determine users’ attentional involvement (i.e., reflecting the fit) in the video content. Such involvement in turn influences users’ emotional enjoyment and satisfaction with the mobile video entertainment service. The empirical results support most of our hypotheses. Two key findings are: (1) in the case of media convergence, the attentional constraint of the target media platform significantly influences user experience during content delivery that may lead to the rejection of media convergence; and (2) the duration of the content interacts with both the attentional constraint of the media platform and the type of interruptions from the environment in determining attentional involvement and emotional enjoyment. We discuss the theoretical contributions and practical implications from our empirical findings.     

基于Ad Hoc网络的反恐处突远程监控系统的研究与实现

远程监控是反恐处突、震后紧急救援和医疗救护安全监控系统的一个子系统,能够实现防控重点区段环境全天候视频监控,为相关部门提供实时的紧急数据传输的远程监控信息。本文依据远程监控特殊环境下视频监控系统的需求,构建了基于Ad Hoc网络的嵌入式远程监控系统和移动语音视讯支持平台。该系统为复杂多变的应用环境提供了高效可靠的视频监控手段,填补了反恐处突监控系统建设的空白。     

基于Android的移动视频监控客户端

近年来,移动通讯网络的迅速发展和Android系统智能手机的普及使得移动视频监控成为一个重要的研究方向. 在深入研究流媒体传输技术、视频编解码技术和SIP协议的基础上,设计了一种具有语音通话功能的移动视频监控系统,并重点对基于Android平台的移动视频监控客户端进行研究与设计.     

mVoIP for P2P service based authentication system using AA authentication server

VoIP (Voice over Internet Protocol), which provides voice calls as well as additional services at cheaper prices than PSTN (Public Switched Telephone Network), is gaining ground over the latter, which had been the dominant telephone network in the past. This kind of a VoIP service is evolving into a dedicated mVoIP service for the smartphone which allows calls to be made at cheap prices using a WiFi network, as the number of smartphone users is skyrocketing as of late. While an increase in the user base is expected for mVoIP, a packet network is an open network which means anyone can easily gain access and so there can be various problems. To mitigate this, in this paper an authentication system is designed which has an AA (Attribute Authority) server added to VoIP in order to increase security and discriminate user access. In this paper a system for addressing security vulnerabilities from the increase in the use of VoIP services and providing differentiated services according to user access privileges is designed. This paper is organized as follows: Chapter 1 gives the introduction; Chapter 2 is on related research; Chapter 3 describes the proposed technique and system; Chapter 4 implements the system and analyzes its the performance; and Chapter 5 gives the conclusions.     

控制时延的主动队列管理算法

针对现有的主动队列管理(AQM)算法造成的队列时延无法满足VoIP、音视频等流媒体传输需求的问题,提出一种直接控制队列时延的主动队列管理算法--DCQA。该算法使用PID控制器计算路由器缓存的数据包丢弃概率,用其对即将进入缓存排队的数据包做丢包判断并采取相应动作,以控制队列时延在期望值以下。实验仿真了3种网络环境下DCQA的性能,链路利用率分别是99.93%、99.88%和99.95%。并且,队列时延分别有50.45%、51.59%、52.4%被控制在期望值以下,比CoDel算法分别提高了3.6%、40.53%、50.69%。实验结果表明,DCQA在不同的网络环境中都可以获得较高的链路利用率,而且控制队列时延的能力优于CoDel算法,适用于流媒体的传输。     

多视点视频无线资源优化

多视点视频是指在场景中放置多台摄像机,记录下多个视点数据,提供给用户视点选择和场景漫游的交互式媒体应用.多个摄像机从不同视角同时拍摄同一场景得到的一组视频信号,每一个摄像机代表一个不同的视角.可同时传输多个空间角度的视频流到用户端,并合成用户所需要的视域图像.多视点视频是一种新型的具有立体感和交互操作功能的视频,是未来一种极具应用前景的多媒体应用.然而,当前多视点的无线网络带宽分配机制中,都没有考虑大量的、不同解码能力的用户共存时的效率问题.一般情况下,合成视域往往需要至少左右两边(两条以上)的参考视频同时传输到用户端,才能使合成的视域质量不低于直接传输的视点质量,使得网络数据量成倍增加.同时,用户的设备性能影响用户感知质量.网络中手机屏幕和高清大屏显示对网络传输视频数据率的要求不同,必须考虑用户设备解码能力的限制,才能真正提供用户满意的感知质量.本文通过考虑移动无线网络带宽约束,考察不同用户端硬件的解码能力、视域大小及带宽消耗,利用博弈理论,使整体网络资源收益最大.本文分别考虑了几种特定场景下多视点视频传输的无线网络的资源分配.第一,已知网络用户的满意度参数,不考虑带宽的限制(带宽充足),如何确定每个用户需要支付的单位价格.第二,在用户个数不确定的条件下,如何判断出可以接入的用户个数和用户需提供的单位价格.第三,同时考虑用户设备对最大场景复杂度解码能力受限以及网络带宽受限两个约束条件,同时进行用户接入控制和多视点的视频质量优化,使得网络的收益和用户的效用得到最大化.本文对提出的算法进行了理论分析,证明了本文参数设置的合理性.在多视点移动网络资源调度中,本文提出的算法可以方便设置所需的价格参数.从视域大小、价格、用户效用、网络收益等各方面对实验性能进行比较.仿真结果显示本方法在同等实验条件下,多视点用户效用提升分别为5%和12%,网络总体收益增加32%.本文算法可以同时满足网络收益和用户整体效用最优,提高多视点视频在多用户下的网络资源利用率.     

基于Android平台的多人视频聊天系统

随着互联网技术和计算机网络技术的快速发展, Android平台系统普遍应用到智能移动终端上,基于Android平台的多人视频聊天系统能使得人们在何时何地都能实现了远程多人视频聊天,提高工作效率,受到很多公司和科研机构的关注.本系统以Websocket为通信信令,利用WebRTC技术传送视频和音频,设计了多人视频聊天系统,包括了服务器及Android客户端;在同一个房间的Android客户端可以实现远程多人视频聊天.本文重点介绍了采用Websocket信令方式和利用WebRTC相关等技术实现了多人视频通信.     

一种远程移动用户访问企业虚拟网的方法

针对远程移动用户给VPN系统带来的配置问题和安全问题,提出了一种包含反向连接和客户端防火墙两种技术在内的远程移动用户访问VPN系统的方法,并给出了这两种技术的实现流程。实验结果表明,反向连接通过VPN网关服务器向远程移动用户建立连接简化了安装配置,客户端防火墙通过动态过滤数据包保证了远程移动用户的安全,并可以扩展防信息泄漏和用户监控功能。     

Deadline-constrained media uploading systems

This paper presents the design, implementation, and performance evaluation of a novel file uploading system. The system automatically uploads multimedia files to a centralized server given a client machine’s hard deadline—the time when a client machine will exhaust its available storage space due to on-going recording of media files. If existing files have not been uploaded and removed from the client machine’s hard disk by the deadlines, existing files may be overwritten or new files may not get created. Our uploading system was designed to provide a practical solution for emerging business needs. For instance, our system can be used in medical practice to gather videos generated from medical devices located in various procedure rooms for post-procedure analysis, and in law enforcement to collect video recordings from police cars during routine patrolling. Here we investigate two upload scheduling algorithms that determine which client machine should upload its file(s) first. We introduce two emergency control algorithms to handle situations when a client machine is about to exhaust its hard disk space. We evaluate the proposed algorithms via simulations and analysis. Our performance studies show that the upload scheduling algorithms and the emergency control algorithms have a significant impact on overall system performance.