Quality utility modelling for multimedia applications for Android mobile devices

With the advances in mobile technologies, smart mobile computing devices have become increasingly affordable and powerful, leading to a significant growth in both the number of advanced mobile users and their bandwidth demands. Moreover multimedia streaming to these high-end mobile devices has become widespread. However, multimedia applications are known to be resource-hungry and in order to cope with this explosion of data traffic, operators have started deploying different, overlapping radio access network technologies. One important challenge in such a heterogeneous wireless environment is to ensure an Always Best Experience to the mobile user, anywhere and anytime. This paper proposes the Quality Utility, a realistic mapping function of the received bandwidth to user satisfaction for multimedia streaming applications. The Quality Utility is mapped to a Google Nexus One Android Mobile device and validated through objective and subjective tests

Modeling Compressible Non-Newtonian Chicken Flow

This paper addresses a few modeling issues relevant for the basic theoretical understanding of the meat flow behavior in simple geometries. We model the meat mixture as a non-Newtonian compressible fluid. Focusing on conceptually easy-to-follow cases like flow in thin molds, or steady incompressible or compressible flow in straight pipes we derive explicit expressions for the velocity and pressure profiles. For the thin moldcase, we formulate a one-dimensional free-boundary problem able to capture the a priori unknown position of the moving meat-air interface. Special attention is payed on the derivation of the free boundary conditions

On the impact of wireless network traffic location and access technology on the mobile device energy consumption

In the context of wireless user’s increasing demands for better device power and battery management, this paper investigates some factors that can impact the power consumption on the energy consumption of mobile devices. The focus is on two factors when performing multimedia streaming: the impact of the traffic location within a WLAN; and the impact of the radio access network technology (WLAN, HSDPA, UMTS). The energy measurement results show that by changing the quality level of the multimedia stream the energy can be greatly conserved while the user perceived quality level is still acceptable. Moreover, by using the cellular interface much more energy is consumed (up to 61%) than by using the WLAN interface

Power-friendly access network selection strategy for heterogeneous wireless multimedia networks

Apart from the number and types of applications available to users of diverse devices with various characteristics, a highly relevant issue in current and future wireless environment is the coexistence of multiple networks supported by various access technologies deployed by different operators. In this context, the aim is to keep the mobile users “always best connected” anywhere and anytime in such a multi-technology multi-application multi-terminal multi-user environment. Multimedia streaming to battery powered mobile devices has become widespread. However, the battery power capability has not kept up with the advances in other technologies and it is rapidly becoming a concern. Since multimedia applications are known to be high energy consumers and since the battery lifetime is an important factor for mobile users, this paper proposes a network selection algorithm which bases its decision on the estimated energy consumption. The proposed solution enables the multimedia stream to last longer while maintaining an acceptable user perceived quality by selecting the least power consuming network

Performance of an adaptive multimedia mechanism in a wireless multi-user environment

With the increasing popularity of accessing multimedia services over different wireless networks, researchers have been trying to develop different adaptive multimedia mechanisms in order to mitigate the impact of fluctuating radio resources. This paper considers the case when multiple users stream video over the same IEEE 802.11b WLAN using a newly proposed Signal Strength-based Adaptive Multimedia Delivery Mechanism (SAMMy). SAMMy makes use of the IEEE 802.11k standard and uses estimated signal strength, location, and packet loss as part of its adaptive mechanism in order to increase user perceived quality for multimedia streaming applications in wireless networks. SAMMy is evaluated by modeling and simulations and compared with another adaptive multimedia delivery mechanism TFRC, in terms of aggregate throughput and fairness. The results show that the proposed signal strengthbased adaptive multimedia delivery scheme outperforms the other scheme in terms of both throughput and fairness when performing video streaming in WLAN

Multiscale modeling of colloidal dynamics in porous media : capturing aggregation and deposition effects

We investigate the influence of multiscale aggregation and deposition on the colloidal dynamics in a saturated porous medium. At the pore scale, the aggregation of colloids is modeled by the Smoluchowski equation. Essentially, the colloidal mass is distributed between different size clusters. We treat these clusters as different species involved in a diffusion-advection-reaction mechanism. This modeling procedure allows for different material properties to be varied between the different species, specifically the rates of diffusion, aggregation, deposition as well as the advection velocities. We apply the periodic homogenization procedure to give insight into the effective coefficients of the upscaled model equations. Benefiting from direct access to microstructural information, we capture by means of 2D numerical simulations the effect of aggregation on the deposition rates recovering this way both the blocking and ripening regimes reported in the literature

Homogenization of a thermo-diffusion system with Smoluchowski interactions

We study the solvability and homogenization of a thermal-diffusion reaction problem posed in a periodically perforated domain. The system describes the motion of populations of hot colloidal particles interacting together via Smoluchowski production terms. The upscaled system, obtained via two-scale convergence techniques, allows the investigation of deposition effects in porous materials in the presence of thermal gradients. Keywords: Homogenization, well-posedness, colloids, thermal-diffusion, cross-diffusion, combustion