The Session Initiation Protocol (SIP) is a multimedia signalling protocol that has evolved into a widely adopted communication standard. The integration of SIP into existing IP networks has fostered IP networks becoming a convergence platform for both real-time and non-real-time multimedia communications. This converged platform integrates data, voice, video, presence, messaging, and conference services into a single network that offers new communication experiences for users. The open source community has contributed to SIP adoption through the development of open source software for both SIP clients and servers. In this paper, we provide a survey on open SIP systems that can be built using publically available software. We identify SIP features for service development and programming, services and applications of a SIP-converged platform, and the most important technologies supporting SIP functionalities. We propose an advanced converged IP communication platform that uses SIP for service delivery. The platform supports audio and video calls, along with media services such as audio conferences, voicemail, presence, and instant messaging. Using SIP Application Programming Interfaces (APIs), the platform allows the deployment of advanced integrated services. The platform is implemented with open source software. Architecture components run on standardized hardware with no need for special purpose investments.

Pavel Segec

Tatiana Kovacikova

A Survey of Open Source Products for Building a SIP Communication Platform

As a greater number of Web Services are made available today, automatic discovery is recognized as an important task. To promote the automation of service discovery, different semantic languages have been created that allow describing the functionality of services in a machine interpretable form using Semantic Web technologies. The problem is that users do not have intimate knowledge about semantic Web service languages and related toolkits. In this paper, we propose a discovery framework that enables semantic Web service discovery based on keywords written in natural language. We describe a novel approach for automatic discovery of semantic Web services which employs Natural Language Processing techniques to match a user request, expressed in natural language, with a semantic Web service description. Additionally, we present an efficient semantic matching technique to compute the semantic distance between ontological concepts.

Asma Adala

Nabil Tabbane

Sami Tabbane

A Framework for Automatic Web Service Discovery Based on Semantics and NLP Techniques

In contrast to what is happening in the Internet-based scenario, the music market in
the mobile scenario is far from being considered a large success. Several studies state
that excessive downloading time and high cost are the main burdens. Motivated by
the growth of social and mobile applications, in this paper we propose an approach
that aims at reducing both the downloading time and the cost to get digital music
when acquired in the mobile scenario. The proposed architecture exploits the usage of
personal communication technologies embedded in cellphones (e.g., Bluetooth and
Wi-Fi) to couple the current distribution model (mainly based on 3G networks), so as
to provide a multichannel distribution model where users are free to redistribute
digital music. The architecture includes a license-based security mechanism that
prevents unauthorized usage of digital music, and makes use of an incentive
mechanism to stimulate and reward the music distribution among customers. By
analyzing pros and cons of the music distribution chain, results show that the
proposed architecture might help in reducing both the downloading time and the cost
to get digital music when acquired in the mobile scenario. Therefore, it might be
helpful to the success of the mobile music scenario.

Marco Furini

Mobile Music Distribution: A Multichannel Approach

Traditional synchronization schemes of multimedia applications are based on temporal relationships between inter- and intrastreams. These schemes do not provide good synchronization in the presence of random delay. As a solution, this paper proposes an adaptive content-based synchronization scheme that synchronizes multimedia streams by accounting for content in addition to time. This approach to synchronization is based on the fact that having two streams sampled close in time does not always imply that these streams are close in content. The proposed scheme primary contribution is the synchronization of audio and video streams based on content. The secondary contribution is adapting the frame rate based on content decisions. Testing adaptive content-based and adaptive time-based synchronization algorithms remotely between the American University of Beirut and Michigan State University showed that the proposed method outperforms the traditional synchronization method. Objective and subjective assessment of the received video and audio quality demonstrated that the content-based scheme provides better synchronization and overall quality of multimedia streams. Although demonstrated using a video conference application, the method can be applied to any multimedia streams including nontraditional ones referred to as supermedia like control signals, haptic, and other sensory measurements. In addition, the method can be applied to synchronize more than two streams simultaneously.

Imad H. Elhajj

Nadine Bou Dargham

Ning Xi

Yunyi Jia

Real-Time Adaptive Content-Based Synchronization of Multimedia Streams

An approach of representing meanings of images based on associative values with lexicons is proposed. For this, the semantic tolerance relation model (STRM) that reflects the tolerance degree between defined lexicons is generated, and two factors of semantic relevance (SR) and visual similarity (VS) are involved in generating associative values. Furthermore, the algorithm of calculating associative values using pixel-based bidirectional associative memories (BAMs) in combination with the STRM, which is easy in implementation, is depicted. The experiment results of multilexicons-based retrieval by individuals show the effectiveness and efficiency of our proposed method in finding the expected images and the improvement in retrieving accuracy because of incorporating SR with VS in representing meanings of images.

Ying Dai

Representing Images&#39; Meanings by Associative Values with Given Lexicons Considering the Semantic Tolerance Relation

Recently, because of 
                  its importance in computer vision and 
                  surveillance systems, object tracking has 
                  progressed rapidly over the last two decades. 
                  Researches on such systems still face several 
                  theoretical and technical problems that badly 
                  impact not only the accuracy of position 
                  measurements but also the continuity of 
                  tracking. In this paper, a novel strategy for 
                  tracking multiple objects using static cameras 
                  is introduced, which can be used to grant a 
                  cheap, easy installation and robust tracking 
                  system. The proposed tracking strategy is based 
                  on scenes captured by a number of static video 
                  cameras. Each camera is attached to a 
                  workstation that analyzes its stream. All 
                  workstations are connected directly to the 
                  tracking server, which harmonizes the system, 
                  collects the data, and creates the output 
                  spatial-tempo database. Our contribution comes 
                  in two issues. The first is to present a new 
                  methodology for transforming the image 
                  coordinates of an object to its real 
                  coordinates. The second is to offer a flexible 
                  event-based object tracking strategy. The 
                  proposed tracking strategy has been tested over 
                  a CAD of soccer game environment. Preliminary 
                  experimental results show the robust performance 
                  of the proposed tracking strategy.

Amany M. Sarhan

Ahmed I. Saleh

Ramy K. Elsadek

A Reliable Event-Driven Strategy for Real-Time Multiple Object Tracking Using Static Cameras

The earth mover's distance (EMD) is a measure of the distance between two distributions, and it
has been widely used in multimedia information retrieval systems, in particular, in content-based
image retrieval systems. When the EMD is applied to image problems based on color or texture,
the EMD reflects the human perceptual similarities. However, its computations are too expensive
to use in large-scale databases. In order to achieve efficient computation of the EMD during query
processing, we have developed “fastEMD,” a library for high-speed feature-based similarity retrievals
in large databases. This paper introduces techniques that are used in the implementation
of the fastEMD and performs extensive experiments to demonstrate its efficiency.

Masami Shishibori

Daichi Koizumi

Kenji Kita

Fast Retrieval Algorithm for Earth Mover's Distance Using EMD Lower Bounds and a Skipping Algorithm

This paper describes an approach to exploit the implicit user feedback gathered during interactive video retrieval tasks. We propose a framework, where the video is first indexed according to temporal, textual, and visual features and then implicit user feedback analysis is realized using a graph-based methodology. The generated graph encodes the semantic relations between video segments based on past user interaction and is subsequently used to generate recommendations. Moreover, we combine the visual features and implicit feedback information by training a support vector machine classifier with examples generated from the aforementioned graph in order to optimize the query by visual example search. The proposed framework is evaluated by conducting real-user experiments. The results demonstrate that significant improvement in terms of precision and recall is reported after the exploitation of implicit user feedback, while an improved ranking is presented in most of the evaluated queries by visual example.

Stefanos Vrochidis

Ioannis Kompatsiaris

Ioannis Patras

Utilizing Implicit User Feedback to Improve Interactive Video Retrieval

The number of items that users can now access when navigating on the Web is so huge that these might feel lost. Recommender systems are a way to cope with this profusion of data by suggesting items that fit the users needs. One of the most popular techniques for recommender systems is the collaborative filtering approach that relies on the preferences of items expressed by users, usually under the form of ratings. In the absence of ratings, classical collaborative filtering techniques cannot be applied. Fortunately, the behavior of users, such as their consultations, can be collected. In this paper, we present a new approach to perform
collaborative filtering when no rating is available but when user consultations are known. We propose to take inspiration from local
community detection algorithms to form communities of users and deduce the set of mentors of a given user. We adapt one
state-of-the-art algorithm so as to fit the characteristics of collaborative filtering. Experiments conducted show that the
precision achieved is higher then the baseline that does not perform any mentor selection. In addition, our model almost
offsets the absence of ratings by exploiting a reduced set of mentors.

Armelle Brun

Sylvain Castagnos

Anne Boyer

From Community Detection to Mentor Selection in  Rating-Free Collaborative Filtering

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Advances in Multimedia publishes research on the technologies associated with multimedia systems, including computer-media integration for digital information processing, storage, transmission, and representation.

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Advances in Multimedia - Table of contents 2011

title

Advances in Multimedia publishes research on the technologies associated with multimedia systems, including computer-media integration for digital information processing, storage, transmission, and representation.

Advances in Multimedia