SIP视频会议系统中存在服务和即时消息服务的研究

如今即时通信软件和视频会议也开始出现了相互接近和融合的趋势,把即时通信融合到视频会议系统中,这样的系统即可以满足用户的即时通信需求,还可以满足中小型商务、企业和组织用户的视频会议需求。通过介绍分析SIP技术优势以及存在和即时消息服务的实现机制,提出了如何在一般的SIP会议系统中实现存在和即时消息服务。     

Exploring factors influencing mobile users' intention to adopt multimedia messaging service

While short messaging service (SMS) is discussed often in recent literature, multimedia messaging service (MMS), a media rich successor of SMS, is seldom heard or understood by mobile users in Taiwan. The adoption rates of MMS are far from satisfactory, implying that there might be some factors keeping the potential users away from using MMS. This research integrates a qualitative method, the Zaltman Metaphor Elicitation Technique, with the quantitative questionnaire survey to elicit and validate underlying factors which influence potential users' attitude and intention toward the adoption of MMS. A research model together with eight hypotheses was formulated, and a questionnaire based survey was administrated to mobile users knowledgeable about mobile messaging services for empirically validating the research model and testing the hypotheses. Our research findings show that relative advantage and ease of use are important factors significantly influencing mobile users' adoption of MMS but the other two antecedents, facilitating conditions and previous experience, do not have significant and direct impacts on mobile users' intention to use MMS. These study results can be referenced by service providers for designing and developing successful business applications to catch the valuable opportunity and benefit of MMS.     

基于MQTT协议的即时消息业务设计与实现

近年来,宽带接入技术正以十分惊人的速度发展.与此同时,移动互联网技术也日益成熟,即时消息业务已成为移动互联时代的应用热点.在互联网中XMPP和SIMPLE被广泛使用,但其并不能很好的适用于移动互联网.采用发布/订阅模型的MQTT协议是一种轻量级的消息传输协议,具有低功耗、节省流量和可扩展性强的优点.本文首先分析了XMPP和SIMPLE协议的不足之处,研究了MQTT协议的消息格式以及协议的使用方式,之后对即时消息业务进行了设计和实现.并在功能和性能上进行了相关的测试和分析.     

一个基于手持移动设备的现代教育信息平台

通过对移动教育特征的分析,设计并实现了一个基于手持设备的移动教育平台。该系统以手持移动计算为载体,采用C／S结构,通过移动通信技术与现代教学手段,将移动教学与传统的网络远程教学相结合,以提高教学效率,增强教和学两个环节的互动性。同时,上下文感知的应用使得系统能够向不同用户提供个性化的服务。     

Two‐phase scale‐based reduction method for fulfilling monitoring service on mobile devices

One of the general location‐based services (LBSs) is the monitoring of real‐time locations of moving objects. When the number of moving objects is large and the task of monitoring is carried out on mobile devices, the monitoring service suffers from constraints of screen size, computing speed, and network bandwidth. In the present paper, a two‐phase scale‐based reduction method (SRM) consisting of a zoom phase and a mosaic phase, is proposed to overcome these constraints. The zoom phase reduces the original monitoring area which, in turn, undergoes further reduction in the mosaic phase. The performance was measured with the use of two ratios: the reduction ratio (RRatio) and the transmission ratio (TRatio). From the experimental results, the lowest RRatio was 52%, i.e. almost half of the original data size was reduced. The lowest average TRatio was also 52% for the worst case, i.e. the entire original monitoring area was displayed on the mobile device. Moreover, the display time was shortened from 14.3 to 0.7 s. These results show that the use of the two‐phase SRM is practical and efficient when applied to the monitoring service on mobile devices. Copyright © 2006 John Wiley & Sons, Ltd.     

一种基于移动服务的系统模型

本文以职业技能鉴定考核系统为研究背景,分析了移动设备与服务器几种传输方式,根据移动设备在系统中有在线和离线不同的应用场景,研究了适用于复杂环境下一种基于移动服务的系统模型。     

基于移动Agent的Web服务组合执行框架设计

对Web服务组合技术深入分析,从Web服务组合的控制执行层面入手,结合移动Agent的优势,提出一种基于移动Agent的Web服务组合执行框架。对于复杂Web服务组合,框架可将其分解成若干相互依赖的任务片,其中任务片对应一个线性的子Web服务组合,然后分配给多个移动Agent进行分布式执行。     

基于移动Agent的地理信息公共服务平台研究与设计

阐述了基于移动Agent的空间信息服务以及移动Agent与空间信息服务结合的优势,在此基础上,对基于移动Agent的地理信息公共服务平台框架和空间信息服务集成流程的实现方式进行了研究与设计。该套框架和流程能够使各级地理信息公共服务平台在不同层面上实现共享与互操作,并为空间信息服务和其他应用/服务之间提供有效的集成机制。     

Determinants of emoticon usage in mobile instant messaging: a construal level theory perspective

Mobile instant messaging is experiencing immense growth, and using emoticons has become a prevalent and highly popular means of communication. The small digital images are ubiquitous, from smartphone applications to social media, and people delight in sending them. Drawing from construal level theory, the aim of this research is to examine the underlying mechanism that drives the usage of emoticons and its usage enjoyment. People with experience using mobile instant messaging were recruited to participate in an online survey, resulting in 202 usable questionnaires. The research model was tested empirically. Covariance-based structural equation modelling was used to analyze the data. The findings highlight that the determinants of individual’s emoticon usage are driven by a dual-route path. One is the self-concept route, where self-image congruity between emoticons and individuals drives psychological ownership, which in turn influences word of mouth (WOM) intention and perceived enjoyment of emoticon use. The other is the utility route, driven by emoticons’ familiarity and perceived synchronicity. The findings reveal the importance of emoticon usage through a contextual lens that shows that a dual-route path has a prominent impact upon these digital-based communication behaviours, which provides important managerial implications.     

3G移动互联网客户服务平台架构设计

随着各种智能手机的普及使用,传统的电话呼叫中心结合分布众多的营业厅模式已经无法满足3G移动手机用户多样化的服务需求。3G移动互联网客户服务平台将建立一个基于3G移动互联网的客户服务体系,通过3G移动互联网的方式向用户提供贴心服务,以文字、图片、演示视频、对讲、在线视频等服务方式远程指导、解答、协助解决用户在使用产品过程中遇到的实际困难和问题。     

基于TTCN-3的移动业务测试平台的设计

为了克服手工测试的缺点,构建了基于TTCN-3的移动业务测试平台。在参考了TTCN-3通用测试系统模型的基础上,针对移动通信协议设计了专门的编解码器和被测系统适配层,并针对各种操作系统平台设计了通用的平台适配层。提出了被测系统适配层采用并行多实体设计,配合采用Socket连接的TRI接口,实现层二协议的分布式处理。通过一个数据呼叫业务的系统测试实例表明了该平台能有效地完成移动业务通信协议的一致性测试。     

采用蚁群算法及移动Agent的网格服务发现设计

在对网格进行分簇的基础上,设计了一种基于蚁群算法及移动Agent的网格服务发现机制模型。通过使用移动Agent技术收集网格服务信息,并将收集到的网格服务信息摘要进行跨簇缓存,以提高蚁群算法中信息素信息的准确性,并且在进行服务查找时采用之前缓存的服务摘要信息作为蚁群算法的启发因子,从而提高网格服务发现的准确性以及发现速度,进而提高网格使用效率。通过仿真实验验证了所述服务发现机制的有效性。     

基于移动Agent实现构件与Web服务的企业应用集成

EJB、CORBA和COM/DCOM这3种构件开发模型已广泛应用于企业应用系统集成中,但其异构性限制了企业之间的沟通.构件与Web服务的合成已成为系统集成的必然需求.为了充分发挥构件与Web服务各自的优点,并有效实现两者的灵活合成,提出了基于移动Agent的企业应用集成方法.最后在实现中验证了该方法的可行性与有效性.     

适合移动Ad hoc网络基于群签名认证的弹性组密钥管理方案*

针对移动Ad hoc网络中的安全组通信系统,提出了一个基于群签名认证的分布式组密钥管理方案。该方案利用门限密码技术并借鉴了PKI证书管理的第三方签名认证思想,在提高认证可信度的同时,极大地减少了密钥协商过程中所需的认证开销。分析表明,该方案具有良好的容错性;达到了第3级信任;能够抵抗网络中典型的主动和被动攻击;具备完美的前向和后向保密性;极大地降低了计算和通信开销。     

MCORE: a context-sensitive recommendation system for the mobile Web

Abstract: Recommendation systems for the mobile Web have focused on endorsing particular types of content to users. Today, mobile service providers have a more direct recommendation channel, namely the short messaging service. Therefore, mobile service providers should consider both the timing and context of recommendation messages (push messages) that are sent to users. Mobile service providers can learn context-specific user preferences by analysing mobile Web use logs and user responses to push messages. In this paper, we present a context-sensitive recommendation system that can be used to select the optimal context in which to send recommendation messages. We call this system the mobile context recommender system (MCORE). We compared user responses to push messages delivered in and out of suitable contexts as determined by MCORE. The precision of push messages delivered within a suitable context was higher than that of messages delivered outside of one.     

基于认知模型的室内移动服务机器人人机耦合协同作业机制

针对老年人和残疾人这类特殊用户群体与服务机器人构成的人机智能系统,提出了基于ACT-R(理性思维的适应性控制)认知架构模型的室内移动服务机器人人机耦合协同作业机制.基于ACT-R认知架构对人机一体化室内移动服务机器人人机协同作业系统进行了总体设计,利用简单自然的人机效应通道,设计了基于ACT-R认知架构的人机耦合界面;通过人-机-环境空间感知耦合,提出并建立了室内移动服务机器人人机一体化协同决策作业机制.最后在室内环境下进行移动服务机器人人机协同作业实验,系统安全高效地完成了作业任务,验证了该机制的有效性.     

K‐MING: A mobile proxy handoff control scheme for proximate group‐based geodata sharing

This work adopts a mobile social network in proximity (MSNP)–centric group touring service concept to share geo–points of interest's (POIs') data among mobile users belonging to the same touring group. In a group‐based touring service, a mobile user can create a group in the MSNP that can consist of some clusters in which some members having the 3G/3.5G/4G cellular network service are selected as cluster leaders to enable their Wi‐Fi hot spot functions as mobile proxies. After that, each group member can join one of the clusters by connecting with a cluster leader's Wi‐Fi hot spot. Thereafter, each cluster leader downloads geo‐POIs' data using 3G/3.5G/4G cellular network and then shares the downloaded POIs' data with its cluster members through its Wi‐Fi hot spot. This work proposed a handoff mechanism such that each mobile user can handoff from its currently connected cluster to the other one that belongs to the same MNSP group. The main handoff concern is that each handheld device only allows a limited number of handheld devices to connect with its Wi‐Fi hot spot at the same time. This work proposed a K‐member‐limited MSNP‐based INter Group handoff scheme called K‐MING to tackle the handoff problem. The performance analysis shows that K‐MING for the group touring scenario has better performance for the sharing of geo‐POIs' data downloading in terms of average power consumption and average downloaded data volume from 3G/3.5G/4G cellular network than that of the individual touring scenario.     

A new algorithm for identity verification based on the analysis of a handwritten dynamic signature

Identity verification based on authenticity assessment of a handwritten signature is an important issue in biometrics. There are many effective methods for signature verification taking into account dynamics of a signing process. Methods based on partitioning take a very important place among them. In this paper we propose a new approach to signature partitioning. Its most important feature is the possibility of selecting and processing of hybrid partitions in order to increase a precision of the test signature analysis. Partitions are formed by a combination of vertical and horizontal sections of the signature. Vertical sections correspond to the initial, middle, and final time moments of the signing process. In turn, horizontal sections correspond to the signature areas associated with high and low pen velocity and high and low pen pressure on the surface of a graphics tablet. Our previous research on vertical and horizontal sections of the dynamic signature (created independently) led us to develop the algorithm presented in this paper. Selection of sections, among others, allows us to define the stability of the signing process in the partitions, promoting signature areas of greater stability (and vice versa). In the test of the proposed method two databases were used: public MCYT-100 and paid BioSecure.     

User behaviours after critical mobile application incidents: the relationship with situational context

Users occasionally have critical incidents with information systems (IS). A critical IS incident is an IS product or service experience that a user considers to be unusually positive or negative. Critical IS incidents are highly influential in terms of users' overall perceptions and customer relationships; thus, they are crucial for IS product and service providers. Therefore, it is important to study user behaviours after such incidents. Within IS, the relationships between the situational context and user behaviours after critical incidents have not been addressed at all. Prior studies on general mobile use as a related research area have recognized the influence of the situational context, but they have not covered the relationships between specific situational characteristics and different types of user behaviours. To address this gap, we examine 605 critical mobile incidents that were collected from actual mobile application users. Based on our results, we extend current theoretical knowledge by uncovering and explaining the relationships between specific situational characteristics (interaction state, place, sociality and application type) and user behaviours (use continuance, word‐of‐mouth and complaints). We have found, for example, that users are less likely to engage in negative behaviours after negative incidents that take place outdoors or in vehicles than after indoor incidents. This is because users often consider indoor environments to be familiar and treat them with established expectations and low uncertainty: users are accustomed to the notion that the applications function indoors just like before. Further, we present practical implications for mobile application providers by suggesting to them which positive critical incidents are the most beneficial to promote and which negative critical incidents are the most crucial to avoid.     

oDect: an RFID‐based object detection API to support applications development on mobile devices

The RFID technology is becoming ever more popular in the development of ubiquitous computing applications. A full exploitation of the RFID potential requires the study and implementation of human–computer interaction (HCI) modalities to be able to support wide usability by the target audience. This implies the need for programming methodologies specifically dedicated to support the easy and efficient prototyping of applications to have feedback from early tests with users. On the basis of our field‐working experience, we have designed oDect, a high‐level language and platform‐independent application programming interface (API), ad hoc designed to meet the needs of typical applications for mobile devices (smart phones and PDAs). oDect aims at allowing application developers to create their prototypes focusing on the needs of the final users, without having to care about the low‐level software that interacts with the RFID hardware. Further, in an end‐user developing (EUD) approach, oDect provides specific support for the application end‐user herself to cope with typical problems of RFID applications in detecting objects. We describe in detail the features of the API and discuss the findings of a test with four programmers, where we analyse and evaluate the use of the API in four sample applications. We also present results of an end‐user test, which investigated strengths and weaknesses of the territorial agenda (TA) concept. The TA is an RFID‐based citizen guide that aids—through time‐ and location‐based reminders—users in their daily activities in a city. The TA directly exploits EUD features of oDect, in particular concerning the possibility of linking detected objects with custom actions. Copyright © 2008 John Wiley & Sons, Ltd.