Wireless CDN video streaming architecture for IPTV

Abstract

Mesohabitat heterogeneity in four mediterranean streams of the Jucar river basin (Eastern Spain)The hydromorphological units or mesohabitats of the headwaters of four Mediterranean streams were studied by classifying them according to their length, width, average and maximum depth, percentage of substrate and water volume. These characteristics of the streams were assessed over four consecutive years (2003)(2004)(2005)(2006). The main objective of the study was to analyse the spatial and temporal pattern of the physical attributes of the mesohabitats. Classification strength and dendrograms were examined for each stream, mesohabitat type, and combination of stream and mesohabitat type and for stream mesohabitat type and year, whereas Nonmetric Multidimensional Scaling ordination (NMDS) was used to analyse classification patterns. The Villahermosa and Ebrón streams were more homogeneous than the Palancia and Vallanca streams, whereas riffles and glides were more homogeneous than pools and rapids. The NMDS indicated that the slow water-velocity (pools, glides) and fast (riffles, rapids) mesohabitats tended to group together. Temporally, the Ebrón stream pools were homogeneous and very stable over the four years, whereas the Vallanca and Villahermosa pools showed a certain degree of variability. The Palancia pools were the most variable and heterogeneous during the study period. These results underscored the importance of separating different types of deep, slow-velocity habitats in mesohabitat inventories and the importance of evaluating habitat classifications in eco-hydromorphological and hydrobiological studies, especially in Mediterranean streams and rivers.Key words: Mediterranean streams, hydromorphological units, mesohabitat, habitat classification, similarity, Iberian Peninsula. (2003)(2004)(2005)(2006) RESUMEN Heterogeneidad del mesohábitat en cuatro ríos mediterráneos de la cuenca del río Jucar (Este de España) Las unidades hidromorfológicas o mesohábitats de cuatro ríos mediterráneos de cabecera fueron estudiadas en función de su longitud, anchura, profundidad media y máxima, porcentaje de sustrato y volumen de cada mesohábitat durante cuatro años consecutivos

Online path selection for video delivery over cellular networks

“…2, we can also say that a good trade-off between wireless channel capacity and network response time is achieved when the number of caches is set in the interval [10,20], with small differences among the scenarios under study. Operating within this range can reduce the network response time to the minimum values in our simulations, with a negligible impact on the wireless channel capacity when using the max-sum algorithm.…”

“…The paper does not take into account the last wireless hop, which is often the bottleneck of the complete delivery chain. Conversely, [10] focuses on the wireless performance analysis (3G, 4G, WLAN) related to video coding and on the efficiency of the placement of the streaming servers. The authors propose a new CDNbased architecture to distribute content to different access networks by placing video streamers in the access networks (including mobile), thus reducing bandwidth consumption and QoS restriction due to the IP core network.…”

Analyzing the combination of different approaches for video transport optimization for next generation cellular networks

“…For instance, [3] focus on wireless performance analysis (third and fourth generation [3G, 4G], WLAN) with respect to video coding and efficient placement of video servers. To overcome the challenge of heterogeneity of access networks, IEEE 802.21 (or Media Independent Hand over, MIH) and 3GPP ANDSF (Access Network Discovery and Selection Function) are making efforts to enable handover between IEEE 802 systems and cellular systems, facilitating the optimization of vertical handover policies [4].…”