Mobile Databases: a Selection of Open Issues and Research Directions

International audienceThis paper reports on the main results of a specific action on mobile databases conducted by CNRS in France from October 2001 to December 2002. The objective of this action was to review the state of progress in mobile databases and identify major research directions for the French database community. Rather than provide a survey of all important issues in mobile databases, this paper gives an outline of the directions in which the action participants are now engaged, namely: copy synchronization in disconnected computing, mobile transactions, database embedded in ultra-light devices, data confidentiality, P2P dissemination models and middleware adaptability

Toward Specifying Multimedia Requirements Using a New Time Petri Net Model

In this paper, we define a model dedicated to the specification of multimedia applications called Pre-emptive Time Petri Nets with synchronizing transitions (STPTPN) as an extension of T-time Petri nets where time is associated with transitions. The model is proposed in the general purpose to model a large scale of multimedia requirements. Thus, resource requirement issues are discussed in this paper, and addressed in the model. To deal with, resources are modelled as special places using a new mechanism called “pre-emptor hyperarc” which lets a transition be “resource strongly-enabled”, “resource-violated” or “resource-violating”. Moreover, two additional mechanisms are considered: A time suspension mechanism uses inhibitor arcs associated with stopwatches and synchronization mechanisms allow the simultaneous firing of a set of transitions (called Rendezvous), according to different schemes. Compared to other existing models, our model is provided with an adapted semantic, designed to represent clearly and accurately time requirements, as well as the complex resource-pre-empting mechanisms that are observed in multimedia systems

MediaSync: Handbook on Multimedia Synchronization

This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences

MAGMA: Music Aligned Generative Motion Autodecoder

Mapping music to dance is a challenging problem that requires spatial and temporal coherence along with a continual synchronization with the music's progression. Taking inspiration from large language models, we introduce a 2-step approach for generating dance using a Vector Quantized-Variational Autoencoder (VQ-VAE) to distill motion into primitives and train a Transformer decoder to learn the correct sequencing of these primitives. We also evaluate the importance of music representations by comparing naive music feature extraction using Librosa to deep audio representations generated by state-of-the-art audio compression algorithms. Additionally, we train variations of the motion generator using relative and absolute positional encodings to determine the effect on generated motion quality when generating arbitrarily long sequence lengths. Our proposed approach achieve state-of-the-art results in music-to-motion generation benchmarks and enables the real-time generation of considerably longer motion sequences, the ability to chain multiple motion sequences seamlessly, and easy customization of motion sequences to meet style requirements

A Framework for Composition, Verification and Real-Time Performance of Multimedia Interactive Scenarios

International audienceInteractive Scores (IS) is a formalism for composing and performing interactive multimedia scenarios. In IS, the composer defines temporal relations (TRs) between temporal objects (TOs) in order to specify the temporal organization of the scenario. During execution, the performer may trigger interaction points to modify the star/stop times of TOs, while the system guarantees that all the TRs are satisfied. IS is implemented in the tool I-SCORE and its semantics is formally defined as a Hierarchical Time Stream Petri Net (HTSPN). However, this model is not able to represent branching behaviors that are necessary to properly deal with applications such as video games and museum installations. Moreover, HTSPN does not provide tools for the automatic verification of critical properties of scenarios. In this work we define a semantics for IS based on Timed Automata (TA) and we show that such model yields to a complete framework to compose, verify and execute interactive scenarios. More precisely, we show that: 1) our model is able to deal with conditional statements in IS; 2) efficient verification techniques can be now used to reason about the written scenarios; and 3) our model allows for a directly implementation on a reconfigurable device, thus guaranteeing a real-time performance