Video Smoothing of Aggregates of Streams with Bandwidth Constraints

Compressed variable bit rate (VBR) video transmission is acquiring a growing importance in the telecommunication world. High data rate variability of compressed video over multiple time scales makes an efficient bandwidth resource utilization difficult to obtain. One of the approaches developed to face this problem are smoothing techniques. Various smoothing algorithms that exploit client buffers have been proposed, thus reducing the peak rate and high rate variability by efficiently scheduling the video data to be transmitted over the network. The novel smoothing algorithm proposed in this paper, which represents a significant improvements over the existing methods, performs data scheduling both for a single stream and for stream aggregations, by taking into account available bandwidth constraints. It modifies, whenever possible, the smoothing schedule in such a way as to eliminate frame losses due to available bandwidth limitations. This technique can be applied to any smoothing algorithm already present in literature and can be usefully exploited to minimize losses in multiplexed stream scenarios, like Terrestrial Digital Video Broadcasting (DVB-T), where a specific known available bandwidth must be shared by several multimedia flows. The developed algorithm has been exploited for smoothing stored video, although it can also be quite easily adapted for real time smoothing. The obtained numerical results, compared with the MVBA, another smoothing algorithm that is already presented and discussed in literature, show the effectiveness of the proposed algorithm, in terms of lost video frames, for different multiplexed scenarios

Optimization of Multiservice Scheduling for Variable Bit Rate Video Transmission in DVB-H Systems

Abstract—Digital Video Broadcasting for Handheld terminals (DVB-H) is assuming an ever growing importance for digital video transmission over wireless terminals. In such a context, Time Slicing has been implemented to achieve a better power saving and manage handover. Specifically, a generic user transmits bursts of data, interspaced by time periods in which no data are transmitted. In this paper, to improve time sliced multiservice transmission effectiveness, the Variable Burst Time (VBT) algorithm is presented and discussed. It dynamically varies the whole set of stream Burst Durations according to input stream data, available channel bandwidth, receiving buffer size and eventually stream priority. Burst Durations are derived by the minimization of a Total Loss Function (TLF) representing the amount of losses of the whole service set. Numerical results show the VBT effectiveness if compared with the time sliced transmission recommended in the DVB guidelines, for different numbers, types and quality degrees of VBR streams, receiving buffer sizes and stream priorities. This suggests that VBT could be efficiently exploited for transmission of VBR streams in DVB-H systems

A smoothing algorithm for time slicing DVB-H video transmission with bandwidth constraints

ABSTRACT DVB-H transmission is assuming an ever growing importance for multimedia data delivery to hand-held terminals of reduced size and limited battery capacities. To minimize terminal s power consumption, DVB-H systems adopt a time sliced transmission in bursts. In such a context, i n this paper a new smoothing algorithm, the Smoothing Algorithm of the Burst (SAB), suitable for the transmission of multimedia streams with high bit rate variability, has been proposed and analyzed. Such an algorithm takes into account receiving buffer size, burst size and available bandwidth variability to reschedule data transmission, with the target to minimize the percentage of loss due to bandwidth and buffer limitations. Numerical results obtained by simulation show the improved performance of SAB compared with the usual unsmoothed data transmission in bursts. SAB can thus be utilized to transmit video streams with higher bit rate and better quality than actually considered in DVB-H systems

Emergency management at sea: A decision support system for Search and Rescue operations

The relevance of Search and Rescue (SAR) maritime operations has been recently emphasized by the increasing migrations by sea. In the Mediterranean area, for example, a number of boats, often crowded, bad equipped and driven by non-professional sailors, travel from the coasts of Africa and Middle East to the ones of Europe: the wideness of the phenomenon and the occurrence of several mournful events have pushed the Italian government and the European Union to conduct large security operations (e.g. Mare Nostrum and Triton). Therefore, it has become urgent to support Maritime Rescue Coordination Centers and Sub—Centers and provide them with a Decision Support System (DSS) for planning and managing SAR operations at sea. This paper illustrates the background and the research methodology of the research project called “Decision support system for maritime environment emergency management”. The project has been carried out from 2011 to 2015 by two Italian companies (i.e. Selex ES — now Leonardo - and Codin SpA) and an Italian public university (i.e. Politecnico di Bari), and funded within the Italian National Operational Programme for "Research and Competitiveness" 2007-2013 (NOP for R&C). Based on an in depth analysis of the literature and a field analysis carried out by adopting Business Process Management techniques, the project team has designed a prototypal DSS that includes some innovative functionalities