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Full-Text Articles in Physical Sciences and Mathematics

Loss Aware Rate Allocations In H.263 Coded Video Transmissions, Xiao Su, Benjamin Wah Dec 2005

Loss Aware Rate Allocations In H.263 Coded Video Transmissions, Xiao Su, Benjamin Wah

Faculty Publications

For packet video, information loss and bandwidth limitation are two factors that affect video playback quality. Traditional rate allocation approaches have focused on optimizing video quality under bandwidth constraint alone. However, in the best-effort Internet, packets carrying video data are susceptible to losses, which need to be reconstructed at the receiver side. In this paper, we propose loss aware rate allocations in both group-of-block (GOB) level and macroblock level, given that certain packets are lost during transmissions and reconstructed using simple interpolation methods at the receiver side. Experimental results show that our proposed algorithms can produce videos of higher quality …


Ontologies In Web Personalization, Magdalini Eirinaki, Michalis Vazirgiannis Oct 2005

Ontologies In Web Personalization, Magdalini Eirinaki, Michalis Vazirgiannis

Faculty Publications

No abstract provided.


Prediction Of Sediment-Bound Nutrient Delivery From Semi-Arid California Watersheds, Emmanuel Gabet, Noah Fierer, Oliver Chadwick Oct 2005

Prediction Of Sediment-Bound Nutrient Delivery From Semi-Arid California Watersheds, Emmanuel Gabet, Noah Fierer, Oliver Chadwick

Faculty Publications

Soil carbon (C), nitrogen (N), and phosphorus (P) are lost from hillslopes in particulate forms through soil erosion. The fate of the eroded C (e.g., sequestration or oxidation) may affect the global C budget, and delivery of N and P to waterbodies can lead to eutrophication. Whereas the magnitude of particulate nutrient losses may be similar to or greater than dissolved losses, it is rarely estimated. We couple a sediment delivery model with measurements of C, N, and P in soil to account explicitly for hillslope sediment transport processes that yield sediment-bound nutrients to fluvial networks. The model is applied …


Microgravity Studies Of Aggregation In Particulate Clouds, Todd B. Sauke, J. R. Marshall, J. N. Cuzzi Jun 2005

Microgravity Studies Of Aggregation In Particulate Clouds, Todd B. Sauke, J. R. Marshall, J. N. Cuzzi

Faculty Publications

Aggregation in clouds of submillimeter quartz and volcanic ash particles was studied in microgravity. Particle clouds generated by pulses of air immediately formed electrostatic filamentary aggregates upon cessation of air turbulence. Manual agitation of experiment chambers produced cm-size loose grain clusters which voraciously scavenged free-floating material in their vicinity. A dipole model accounts for these observations. Experimental results have ramifications for the behavior of natural cloud systems and primary accretion of solids in the early solar nebula.


Ikum: An Integrated Web Personalization Platform Based On Content Structures And User Behavior, Magdalini Eirinaki, Joannis Vlachakis, Sarabjot Anand Jan 2005

Ikum: An Integrated Web Personalization Platform Based On Content Structures And User Behavior, Magdalini Eirinaki, Joannis Vlachakis, Sarabjot Anand

Faculty Publications

Web personalization is the process of customizing a web site to the needs of each specific user or set of users, taking advantage of the knowledge acquired through the analysis of the user’s navigational behavior. The objective of the I-KnowUMine project (IKUM) is to develop an integrated platform (referred to in the paper as the “IKUM system”) that uses state of the art technology and research results from different application domains in order to provide the basis for the development of online services in a wide range of application areas, presenting personalized content, services and applications to users in a …


Mass-To-Light Ratio Gradients In Early-Type Galaxy Haloes, N. R. Napolitano, M. Capaccioli, Aaron J. Romanowsky, N. G. Douglas, M. R. Merrifield, K. Kuijken, M. Arnaboldi, O. Gerhard, K. C. Freeman Jan 2005

Mass-To-Light Ratio Gradients In Early-Type Galaxy Haloes, N. R. Napolitano, M. Capaccioli, Aaron J. Romanowsky, N. G. Douglas, M. R. Merrifield, K. Kuijken, M. Arnaboldi, O. Gerhard, K. C. Freeman

Faculty Publications

Owing to the fact that the near future should see a rapidly expanding set of probes of the halo masses of individual early-type galaxies, we introduce a convenient parameter for characterizing the halo masses from both observational and theoretical results: ∇ℓϒ, the logarithmic radial gradient of the mass-to-light ratio. Using halo density profiles from Λ-cold dark matter (CDM) simulations, we derive predictions for this gradient for various galaxy luminosities and star formation efficiencies εSF. As a pilot study, we assemble the available ∇ℓϒ data from kinematics in early-type galaxies – representing the first unbiased study of halo masses in a …