Despite the relevance of the MPEG-21 standard, little has been done about the modeling of authoring tools and players for the production/consumption of MPEG-21 digital objects. The design and implementation of MPEG-21 tools present several critical points to be solved at the architectural level, so as to ensure security and provide a suitable support and the requested flexibility for manipulating any kind of digital resource, according to the spirit of MPEG-21 standard. This paper presents the AXMEDIS core model and components for MPEG-21 content authoring tools and players. The proposed architecture provides both data manipulation flexibility and a high level of security when digital resources are used. The same architecture can be used to develop any other MPEG-21 DI tools. The architecture presented has been adopted to build authoring and player tools developed for the AXMEDIS IST FP6 R&D European Commission project

The design and implementation of MPEG-21 players and authoring tools presents several critical points to be solved. One of the most relevant is the security level and protection processing in the players. This paper presents a solution for the realization of components in charge of enforcing Digital Rights Management in AXMEDIS tools for MPEG-21 digital content. The proposed architecture provides functionalities to create both trusted environment on the client side and dynamic protection and unprotection of digital content including digital resources and their organization and metadata. The same solution can be used to achieve the desired security level in any other MPEG-21 player or authoring tool. The architecture presented hereinafter has been adopted to enforce protection on authoring and player tools developed for the AXMEDIS IST FP6 R&D European Commission project

The paper on Comments on "An Interval Logic for Real-Time System Specification" presents some remarks on the comparison examples from TILCO and other logics and some slips on the related examples. This paper gives evidence that such issues have no impact on the validity of the TILCO theory of paper and provides some further clarifications about some aspects of the comparison

Over the last, years, software quality has become one of the most important requirements in the development of systems. Fault-proneness estimation could play a key role in quality control of software products. In this area, much effort has been spent in defining metrics and identifying models for system assessment. Using this metrics to assess which parts of the system are more fault-proneness is of primary importance. This paper reports a research study begun with the analysis of more than 100 metrics and aimed at producing suitable models for fault-proneness estimation and prediction of software modules/files. The objective has been to find a compromise between the fault-proneness estimation rate and the size of the estimation model in terms of number of metrics used in the model itself. To this end, two different methodologies have been used, compared, and some synergies exploited. The methodologies were the logistic regression and the discriminant analyses. The corresponding models produced for fault-proneness estimation and prediction have been based on metrics addressing different aspects of computer programming. The comparison has produced satisfactory results in terms of fault-proneness prediction. The produced models have been cross validated by using data sets derived from source codes provided by two application scenarios.