1,720,965 research outputs found
Parameters optimization for scalable multiple description coding scheme based on spatial subsampling
No full textImproved multicast algorithm for overlay multicast in P2P based video streaming
No full textIn this paper we introduce some significant improvements to a well known algorithm for multicast in overlay networks, namely ZigZag. The improvements are mainly related to a better handling of peer churn, avoiding service interruption to the subtree rooted at the departed node. Furthermore, more realistic constraints on node heterogeneity are introduced so that the multicast tree is allowed to grow unbalanced. Since the target is a video streaming service, additional constraints are related to a minimum serving quality for outgoing links. This translates in a maximum number of childred for each node depending on its outgoing link capacity. It is also shown that exploiting the overlapped control structure with scalable coded video it is possible to minimize service interruptions due to peers departure while minimizing signalling overhead. The changes have been implemented and validated using network simulator 2 to show the effectiveness of the procedures
An end to end simulator for performance comparison of different TCP schemes over UTRA channels
No full textHybrid ARQ Based on Rateless Coding for Wireless Sensor Networks
No full textThis paper shows an Incremental Redundancy Hybrid automatic repeat request (HARQ) scheme, based on rateless coding, for wireless sensor network (WSN) protocols. The proposed approach proved to be effective under energy consumption constraints, making it suitable for possible applications to WSNs. Moreover, the use of a rateless coding scheme increases the average throughput by limiting the length of retransmitted packets. Performance are evaluated through simulations in terms of average goodput and average energy consumption, comparing the presented solution with the traditional ARQ scheme employed in the IEEE 802.15.4 standard for WSNs. Results have been obtained using a novel network simulation model for rateless code transmissions based on information theoretic measures
Long-distance monitoring of physiological and environmental parameters for emergency operators
No full textThe recent disaster provoked by the earthquake in middle Italy has pointed out the need for minimizing risks endangering rescuers' lives. An European Project called ProeTEX (Protection e-Textiles: MicroNanoStructured fiber systems for Emergency-Disaster Wear) aims at developing smart garments able to monitor physiological and environmental parameters of emergency operators. The goal is to realize a wearable system detecting health state parameters of the users (heart rate, breathing rate, body temperature, blood oxygen saturation, position, activity and posture) and environmental variables (external temperature, presence of toxic gases and heat flux passing through the garments) and remotely transmitting useful information to the operation manager. This work presents an overview of the main features of the second prototype realized by ProeTEX with particular emphasis to the sensor's body network and the long distance transmission of signals
- …
