JMM Abstracts 

Vol.2 No.2 June 15, 2006
Editorial (pp097-097)
        I. K. Ibrahim                       

Research articles:
Content Adaptation Based Approach for Ubiquitous Multimedia (pp098-0111)
        H.-P. Wang, Z.-W. Yu X.-S. Zhou, T. Zhang, and D. Xiang 
Content adaptation is playing an important role in ubiquitous multimedia, however it is a challenging work due to the high degree of dynamism and heterogeneity of the ubiquitous computing environments, where hundreds of devices provide information, and thousands of terminals access these information. Recently, some researchers proposed to address this issue by dynamically organizing services or components into customized applications at runtime. However, due to the maintenance of the dependencies between services or components, this kind of system becomes more complicated with the growth of the system scale. Programming for these systems is also error-prone. This paper discusses the issues of content adaptation based approach for ubiquitous multimedia, and presents a prototype system, called UbiCon system. By abstracting media streams into generic CONTENT entities, the system provides a simple and powerful means for services to operate media stream. The CONTENT is dynamically created by the system at runtime, and essentially has local association with related services. As a result, the CONTENT is also used as a loosely coupling method for cooperating associated services. By abstracting services with a T model, the services can effectively cooperate together with other services. As a result, a collection of sophisticated applications can be built with this simple and effective services model.

Content Adaptation on mobile devices using MPEG-21 (pp112-123)
        A. A. Sofokleous and M. C. Angelides
Content authors pursue the creation of mobile content that is ubiquitous in nature, i.e. published once only but being available anywhere, anytime, on any device. However, mobile content must accommodate varying resource constraints on different devices such as reduced resolution, processing power, memory and network bandwidth. In this chapter, we discuss those issues that are pertinent to multimedia content adaptation across different devices with reference to MPEG-21ís Digital Item Adaptation for mobile devices. In particular, we consider how the range of aspects that affect a mobile usage environment, i.e. network, natural environment, device and user characteristics, could be used alongside a set of user-defined limitation and optimization constraints, to adapt content and thereby maximize quality of service.

Bazaar: A Middleware for Physical World Abstraction (pp124-145)
        K. Fujinami and T. Nakajima
In this paper, we propose a middleware, Bazaar, for building location and context-aware services without the need to consider the detail of information capturing, but to allow a developer to concentrate on his/her main task, i.e. the application logic development. Bazaar abstracts the physical world by separating the structures of information and the usage from utilization. It also serves as a shared ``physical information repository" to maintain consistency among various applications in the environment, which is often called the world model.   The world model in Bazaar contains a location model and an artefact model. The former represents the containment relationship between a unit space like a house and unit regions like the washroom. The static specification and dynamically changing status of an artefact is handled within the artefact model.  Here, a sensor augmented artefact acts as a building block for a smart space. Usually, the artefact has a primary role and we have a prior understanding of the meaning o the state-of-use. We call such an artefact a sentient artefact.  This paper describes the design and implementation of Bazaar with a programming model that reflects the relationship between locations and objects in the physical environment. Furthermore, we describe experiences from various application development experiments with Bazaar.

Listening Comprehension of English Second Language with Mobil Devices  (pp146-165)
        M. Djoudi
The use of the mobile devices in language learning has been developed at very high speed these last years. Thus, we are witnessing many research and development projects, methodologies, and scientific publications. However, the interest in research related to listening comprehension competence remains relatively low. In this paper, we propose a simple and original approach, which aims to use mobile devices for listening comprehension of foreign language especially English Second Language for French learners.   This approach is based on an easy to use technology that makes it possible for learners to work, anywhere and at their own rhythm, the listening comprehension of a foreign language. With the mobile MP3 player, the learner can carry a worth of English lessons, practicing pronunciation and conversation drills with the audio tracks. He can download from web based mobile-learning environment (named Nomadís Lang) the MP3 audio tracks and written lessons (created par teachers) and read them on any mobile device (PDA, Pocket PC or Laptops, etc.).  The paper starts with the summary of mobile devices, language skills and listening comprehension. It then highlights our approach of the use of mobile devices for learning English second language. Finally a learner evaluation is performed. The paper ends with the discussion of results and conclusion

A Novel Approach for Improving the Quality of Service for Wireless Video Transcoding  (pp167-186)
        A. M. A. Ahmad and S.-Y. Lee
To deliver streaming video over wireless networks is an important component for most interactive multimedia applications running on personal wireless handset devices. Such personal devices should be inexpensive, compact, and lightweight. Wireless channels have limited bandwidth and a high channel bit error rate. Delay variation of packets due to network congestion with the high bit error rate lessens the quality of video at the handheld device. Therefore, mobile access to multimedia content requires video transcoding functionality at the edge of the mobile network for interworking with heterogeneous networks and services. Under certain conditions, the bandwidth of a coded video stream needs to be drastically reduced. We propose a cost-efficient mechanism for improving the quality of service (QoS) delivered to the mobile user, by introducing a robust and efficient transcoding scheme as proven by extensive experiments. The proposed approach refines the motion vectors value without the need to re-perform the motion estimation process. Then the transcoding mechanism will be preformed using the new fine motion vectors. Thus, great amounts of computing resources have been saved. Exceptional performance is demonstrated in the experiment results, as these experiments were designed to verify and prove the robustness of the proposed approach.              

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