基于XMPP通信协议的即时通讯研究

XMPP是一种基于Jabber协议可用于服务类实时通讯、表示和需求响应服务中的XML数据元流式传输的即时通讯协议。XMPP协议允许因特网用户向因特网上的其他任何人发送即时消息,即使其操作系统和浏览器不同。随着互联网的普及和发展,即时通信已经成为人们交流的重要手段。很多企业需要一个专门面向商业应用的与该行业业务相关的即时通信软件,来加强企业之间、企业内部、企业与客户之间的信息交流。现基于XMPP协议和Android智能手机开发一款即时聊天(IM)工具,此通讯工具涉及注册、登陆、添加朋友、删除朋友和聊天,还包括一个基于后台的音乐播放器。     

An empirical investigation of deception behavior in instant messaging

Various disciplines have extensively studied deception in human communication. With the increasing use of instant messaging (IM) for both informal communication and task performance in the work place, deception in IM is emerging as an important issue. In this study, we explored the behavioral indicators of deception in a group IM setting. The empirical results showed that three types of nonverbal behaviors and three types of verbal behaviors that were investigated could significantly differentiate deceivers from truth tellers. The findings potentially can broaden our knowledge of deception behavior in human communication and improve deception awareness and deception detection in the cyberspace.     

A study of Internet instant messaging and chat protocols

Instant messaging (IM) and network chat communication have seen an enormous rise in popularity over the last several years. However, since many of these systems are proprietary, little has been described about the network technology behind them. This analysis helps bridge this gap by providing an overview of the available features, functions, system architectures, and protocol specifications of the three most popular network IM protocols: AOL Instant Messenger, Yahoo! Messenger, and Microsoft Messenger. We describe common features across these systems and highlight distinctions between them. Where possible, we discuss the advantages and disadvantages of different technical approaches used in these systems to support different features and functions. We also briefly discuss ongoing efforts to standardize IM and chat-based protocols in IETF and other standards bodies.     

“类KIK”手机即时通信软件的网络数据分析

近年来,国内外以Kik Message和微信为代表的“类Kik”系列软件人气暴涨,吸引了大批用户,成为移动互联网应用的亮点.而随之带来的安全问题也对互联网有害信息监测和对抗提出了更高的要求.本文以Kik Message和微信为研究对象,对该类软件的网络数据进行分析,并得出相应的监测和对抗结论.     

A heuristic approach to establishing punctuation convention in instant messaging

Instant Messaging (IM) features informal writing styles such as the omission of punctuation. Punctuation plays an important role in representing prosody and facilitating syntactic processing during communication. The discrepancy between the recognized importance and actual inadequate usage of punctuation in IM calls for establishing punctuation convention for more effective online communication. The research uniquely reported here addressed two research questions. The first was whether punctuation had an impact on the effectiveness of IM. The results of an empirical study showed that the majority of surveyed participants perceived punctuation to be somewhat important. This led to the investigation of the second research question: how to restore omitted punctuation in instant messaging to help develop punctuation convention effectively? We designed and implemented a technical solution for recovering punctuation based on heuristics rules and an evaluation of this approach showed satisfactory performance. A detailed analysis of punctuation in archived instant messages revealed several patterns of omitted punctuation. The findings of this research not only advance our understanding of the stylistic convention, but also provide positive evidence for establishing punctuation convention in IM. As IM continues to pervade daily communication, punctuation convention in IM deserves closer attention.     

基于桌面云终端的无线即时通信系统设计

为实现有效共享IT系统信息,提出基于桌面云终端的无线即时通信系统设计。首先,利用集群服务器建立私有云环境,在此条件下即时通信系统可通过分层次异构融合的无线移动P2P构建完成,移动设备存储终端由云终端提供,将代理节点设置在无线P2P网络边界上并使其融入无线P2P网络中,在无线移动网络和云终端完成异构融合的基础上实现即时通信系统的分层分级管理;其次,在考虑即时通信性质的基础上,使用C/S模式和客户端间的点对点模式在网络通信中设计即时通信系统的客户登录模块以及状态控制模块等功能模块。通过测试实验表明,以建立在桌面云终端为基础的无线即时通信系统能够快速反应且稳定性较强。     

移动网络下高可靠即时通信系统的研究与应用

随着移动互联网时代的到来,出现了大量优秀的即时通信软件,其中成熟的即时通信技术都不公开,而开源的即时通信框架存在较多问题,容易出现丢包、消息延迟。针对上述问题,设计了移动网络下高可靠即时通信系统,弥补了开源通信框架设计中的不足,并提出对通用即时通信技术的改进方法。首先提出了高性能通信长链接和时间片轮转算法,采用了消息握手协议和消息加密的方法,同时改进了通信链接状态检测算法,并提出双服务权限认证方法,保证了即时通信系统的安全性。实验中测试系统包含了设计的即时通信框架,实验结果证明了系统的即时性和高可靠性。     

基于Reactor模式的即时通信服务器的设计与实现

针对当前移动互联网环境下中小型企业办公人员对即时通信存在一定要求的问题,提出了一种C++平台下基于Reactor模型的即时通讯系统的设计与实现。文中分别就系统整体架构和具体实现进行了说明,本系统主要通过C++网络编程实现即时通信,具有支持大量客户端并发访问的能力,兼具低延迟和高稳定性等特点。     

Impact of mobile instant messaging applications on signaling load and UE energy consumption

Mobile Instant Messaging (MIM) applications transmit not only user-triggered messages (UTMs), but also keep-alive messages (KAMs) via radio access network, which induces heavy burden in control plane channel and wastes user equipment (UE) energy consumption. In this paper, we deduce the joint distribution of KAM period and UTM mean interval from the MIM application traffic characteristics. Correlating the joint distribution with radio resource control (RRC) state machine in LTE networks, we derive two analytical expressions for the control plane signaling load and UE energy consumption respectively. Then, the variation of signaling load and energy usage is demonstrated with different settings of RRC release timer, KAM period and UTM mean interval. The analysis indicates that KAM period is the upper bound of RRC release timer when reducing the signaling load. Besides, five times of UTM mean interval is the upper bound of KAM period when reducing the UE energy consumption and signaling load. These results can guide both network operators and MIM application developers to properly set control parameters for balancing the signaling load and UE energy consumption.

     

Effects of gratification-opportunities and gratifications-obtained on preferences of instant messaging and e-mail among college students

The traditional approach of using gratifications-obtained in the study of motives in the adoption and use of media puts much emphasis on the users’ perspectives and pays less attention to the attributes of the medium. This exploratory research confirms the important role of gratification-opportunities in studying media preference for computer-mediated communication.     

Enhancing customer loyalty to mobile instant messaging: Perspectives of network effect and self-determination theories

Mobile instant messaging (MIM) apps are popular information and communication technologies (ICTs). As known for ICTs, network effect variables such as perceived network size and perceived complementarity are important for determining user loyalty. However, there is insufficient research on why they are determinants, i.e., knowing the underlying mechanism. Grounded in network effect and self-determination theories, we study such underlying mechanism. Based on an analysis of responses from an online survey of 292 participants using structural equation modelling, we find that the network effect variables of perceived network size and perceived complementarity are positively related to three user-perceived values, namely user-perceived functional, self-expressive, and social values. They are, in turn, positively related to satisfaction of the needs for competence, autonomy, and relatedness, respectively, that further leads to user loyalty. This study contributes to the MIM literature by being the first to use the three user-perceived values and satisfaction of the three needs as novel process variables to construct a model for explaining the impacts of network effect variables on user loyalty to MIM apps. This study provides the insight that MIM providers can more effectively enhance user loyalty by providing the three values that users appreciate and satisfying the three needs, when increasing and advertising their network sizes and availability of complementary offerings.     

Enabling Stable Lithium Metal Anode through Electrochemical Kinetics Manipulation

The surface morphology of Li metal anode significantly dictates the stability and safety of Li metal batteries. The key parameters for morphological control and causes for dendritic growth of Li anode are still not clear. Although the plating kinetics is generally believed to be associated with Li growth habits, the detailed models are still not well defined. In this work, the temperature effect on the stability and efficiency of Li anode is systematically investigated in a variety of electrolyte composition for Li metal batteries. A dendrite‐free growth mechanism is observed, and a high Coulombic efficiency up to ≈99.4% in Li||Cu cells is achieved by tuning the deposition behaviors at elevated temperatures. The results provide insights into the Li dendrite growth mechanism and general principle for developing stable Li anode.     

Talking with cars-traffic messaging

Fleet management, traffic control and vehicle navigation are being revolutionised by developments in road transport informatics. One of the unsung heroes supporting the new technologies is traffic messaging, which is the exchange of traffic-related digital coded information between traffic control centres, traffic information publishers and broadcasters, and the vehicles and drivers. The author discusses the application areas of traffic messaging and then describes the mobile radio and satellite communications technology which makes traffic messaging possible. The author then describes the European Community, DRIVE programme before addressing some of the obstacles to be overcome if traffic messaging is to become more widespread     

Enabling efficient reprogramming through reduction of executable modules in networked embedded systems

We present a systematic modular design approach for networked embedded systems. We effectively reduce the module file size to enable efficient network reprogramming, while at the same time retain necessary information to maintain module flexibility. We further handle module dependencies in a fine-grained manner, which improves system reliability while keeping the system configuration to its minimum requirement. We have implemented the modular approach based on a micro embedded OS, SenSpire OS, for AVR and MSP430 platforms. The evaluation results show that the proposed SELF module file format is 4.6–7.6 times smaller than the standard ELF format, and is 1.6–2.4 times smaller than the CELF format (a Compact ELF format for the Contiki OS). SELF retains necessary information to enable flexible modular programming and inter-module communications. We have further developed a long-term energy efficiency model to explore the tradeoffs of different reprogramming approaches.     

Enabling seamless multimedia wireless access through QoS‐based bandwidth adaptation

Effective support of real‐time multimedia applications in wireless access networks, viz. cellular networks and wireless LANs, requires a dynamic bandwidth adaptation framework where the bandwidth of an ongoing call is continuously monitored and adjusted. Since bandwidth is a scarce resource in wireless networking, it needs to be carefully allocated amidst competing connections with different Quality of Service (QoS) requirements. In this paper, we propose a new framework called QoS‐adaptive multimedia wireless access (QoS‐AMWA) for supporting heterogeneous traffic with different QoS requirements in wireless cellular networks. The QoS‐AMWA framework combines the following components: (i) a threshold‐based bandwidth allocation policy that gives priority to handoff calls over new calls and prioritizes between different classes of handoff calls by assigning a threshold to each class, (ii) an efficient threshold‐type connection admission control algorithm, and (iii) a bandwidth adaptation algorithm that dynamically adjusts the bandwidth of an ongoing multimedia call to minimize the number of calls receiving lower bandwidth than the requested. The framework can be modeled as a multi‐dimensional Markov chain, and therefore, a product‐form solution is provided. The QoS metrics—new call blocking probability (NCBP), handoff call dropping probability (HCDB), and degradation probability (DP)—are derived. The analytical results are supported by simulation and show that this work improves the service quality by minimizing the handoff call dropping probability and maintaining the bandwidth utilization efficiently. Copyright © 2006 John Wiley & Sons, Ltd.     

MHEGAM-a multimedia messaging system

MHEGAM (MHEC-1 Advanced Mail) is a complete multimedia messaging system for the creation, exchange, and restitution of multimedia messages that express spatial and temporal synchronization among their components. MHEGAM can be based on the standard messaging systems X.420 or MIME. We present the multimedia extensions MHECAM-X.420 and MHEGAM-MIME and discuss the multimedia message format and architecture components for both systems     

On the performance of web services,google cloud messaging and firebase cloud messaging

Smartphones and other connected devices rely on data services, such as Web Services (WS), Google Cloud Messaging (GCM) and Firebase Cloud Messaging (FCM), to share the information they collect or use. Traditionally, these services were classified according to the average number of bytes transmitted or their delivery time. However, when dealing with battery-operated devices, another important parameter to be taken into account is their power consumption. Furthermore, software designers and developers often do not consider the efficiency of a data communication system, but are simply concerned about ease-of-use and response time. In this paper, we compare FCM, GCM and two types of WS, namely Simple Object Access Protocol (SOAP) and REpresentational State Transfer (REST) WS in terms of delay, data efficiency, and power consumption. The final outcome is that RESTful WS outperforms all others, making GCM and FCM a viable alternative only when the amount of data to be transmitted is very limited, or when the mobile application requires the advanced services offered by FCM or GCM only.     

Transferring bioelasticity knowledge through haptic interaction

This study establishes a practical environment for transferring knowledge on bioelasticity between expert and trainee medical practitioners. Through haptic interaction with a deformable virtual anatomical model, experts set the model's elasticity conditions by simulating a surgical procedure. Trainees experience the elasticity by attempting the same surgical manipulation.