Vol.3 No.1 March 15, 2007 

Editorial (001-002)
        I. Ibrahim          

Mobility Support in IP Multicast: Proposals Review and  Evaluation (003-014)  
        A. Hassan, F. Anwar and S.A.L. Irhayim
Multicast is one-to-many or many-to-many delivery of packets. Multicast data delivery increases network efficiency and decreases the bandwidth demand by eliminating the need for redundant packets when more than one client wishes to access a data stream. With this in mind, the importance of multicast routing becomes evident. However, the main drawback of the current multicast routing protocols is that they are developed without mobility in mind. It is anticipated that many users are likely to become mobile in the near future, thus mechanisms are needed to support multicast for the groups whose members are both mobile and static. The main aim of this paper is to study and evaluate the current approaches for mobility support in multicast. It presents the main concepts of multicast.  It also performs a study and evaluation to the Internet Engineering Force Task (IEFT) approaches to handle the mobility of the multicast users. Then the discussion is extended to include different protocols that are introduced to overcome the limitations of IEFT proposals highlighting their advantages and limitations.

On Some Current Results of Graph Theory for ad-hoc Networks (015-033)  
        G. De Marco and L. Barolli  
The goal of this paper is twofold. Firstly, we present results from graph-theory which can be used to understand the fundamental properties of ad-hoc networks and wireless sensor networks. Graph-theory is a well studied branch of discrete mathematics, and it has been applied in many knowledge fields, e.g. social network, Internet tomography and epidemiology. We review literature results from the point of view of the designer of an ad-hoc network, who must set simulation parameters in order to predict the behaviour of the real network. Secondly, we study the impact of the asymmetries of radio links on the connectivity properties of an ad-hoc network. To the best knowledge of the author, this further hypothesys has been addressed in the case of geometric random graph only, but not for radio models with randomnesses. As expected, we found that randomness in the radio model directly affects the distribution of the asymmetries and the connectivity properties. This result can be very useful in the understanding of more complicated aspects of ad-hoc nets, like routing and coordinated wake-up in power saving techniques.

On Asynchronous Training in Sensor Networks (034-046)  
        Q.-W. Xu, R. Ishak, S. Olariu, and S. Salleh 
Due to their small form factor and modest energy budget it is infeasible to endow individual sensors with GPS capabilities. Yet, numerous applications require sensors to have a coarse-grain location awareness. The task of acquiring this coarse-grain location awareness is referred to as training. The main contribution of this work is to propose a fully asynchronous training protocol for massively-deployed sensor networks. The sensors wake up according to their internal clock and are not engaging in synchronization with the sink. Our protocol is lightweight and simple to implement. We show analytically that in spite of the lack of synchronization, individual sensors are trained energy-efficiently. The analytical results have been confirmed by simulation.

Evaluation of the Delivered MPEG Video Quality over Wireless Channels (047-064)
        C.-H. Ke, C.-H. Lin, G.-K. Shieh, W.-S. Huang, A. Ziviani 
We propose an analytical model to derive from the packet loss rate an objective application-level metric, the decodable frame rate (Q), thus allowing the evaluation of the packet loss effect on the streaming MPEG video quality over wireless channels, as perceived by end users. We analyze the effects on video quality using a random uniform error model and the Gilbert-Elliot (GE) error model (for burst errors modeling) to represent wireless lossy channels. Results obtained through extensive simulations indicate the effectiveness of our proposed model for both the random uniform and GE error models, provided that the packet error rate remains relatively low. Moreover, owing to the well-acceptance of PSNR as an objective performance metric that takes into account the video content to assess the video quality, we also investigate the relationship between PSNR and Q as well as their comparative performances as metrics for video quality assessment. Results show that the Q metric reflects well the behavior of the PSNR metric, whereas being much less time-consuming.

Multimedia Applications for Mobile Devices: Issues and Requirements for Authoring Tools and Development Platforms (065-087)
        D. Economou, D. Gavalas, M. Kenteris, and K. Micha
This paper explores requirements application authoring tools should satisfy for the development of cultural applications tailored for deployment on Personal Digital Assistants (PDAs) and mobile phones. The paper reviews the use of mobile technologies in the context of cultural organizations and tourism. It identifies and evaluates the development and design facilities provided by state-of-the-art multimedia application development tools for PDAs and mobile phones: Macromedia Flash Lite, Navipocket and Java 2 Micro Edition. It describes the way these tools have been used in the implementation phase of two projects that have been developed at the Cultural Heritage Management Lab (CHMLab), at the Department of Cultural Technology and Communication, University of the Aegean. These projects focus on the use of PDAs and mobile phones for providing cultural and tourist information, keeping the visitors’ interest and attention, as well as promoting various cultural organizations’ and tourist facilities. Based on these two case studies the paper extracts a set of PDA and mobile phone application requirements. The paper concludes with a set of suggestions related to the way application authoring tools should be exploited in order to gratify application and designer needs for developing operational and profitable cultural and tourist applications.

Potentials of SMIL Applications for Mobile Devices (088-100)  
        H. Stormer and M.E. Ritz 
The Synchronized Multimedia Integration Language (SMIL) is an XML based language for the synchronization of multimedial content. SMIL can be used to show all kinds of presentations on stationary and mobile devices. For the latter, a subset called SMIL mobile profile is standardized. SMIL has already started to influence certain mobile applications. Worth mentioning are electronic learning and mobile marketing, who both profit from utilizing SMIL presentations. This paper gives an introduction to SMIL. The different modules that establish a SMIL presentation are presented. Afterwards, mobile application scenarios that benefit from the usage of SMIL are shown, including e-learning, mobile communication and mobile marketing.