4,229 research outputs found
Towards an Efficient Context-Aware System: Problems and Suggestions to Reduce Energy Consumption in Mobile Devices
Looking for optimizing the battery consumption is
an open issue, and we think it is feasible if we analyze the
battery consumption behavior of a typical context-aware
application to reduce context-aware operations at runtime.
This analysis is based on different context sensors
configurations. Actually existing context-aware approaches are
mainly based on collecting and sending context data to external
components, without taking into account how expensive are
these operations in terms of energy consumption. As a first
result of our work in progress, we are proposing a way for
reducing the context data publishing. We have designed a
testing battery consumption architecture supported by Nokia
Energy Profiler tool to verify consumption in different scenarios
Keep Your Nice Friends Close, but Your Rich Friends Closer -- Computation Offloading Using NFC
The increasing complexity of smartphone applications and services necessitate
high battery consumption but the growth of smartphones' battery capacity is not
keeping pace with these increasing power demands. To overcome this problem,
researchers gave birth to the Mobile Cloud Computing (MCC) research area. In
this paper we advance on previous ideas, by proposing and implementing the
first known Near Field Communication (NFC)-based computation offloading
framework. This research is motivated by the advantages of NFC's short distance
communication, with its better security, and its low battery consumption. We
design a new NFC communication protocol that overcomes the limitations of the
default protocol; removing the need for constant user interaction, the one-way
communication restraint, and the limit on low data size transfer. We present
experimental results of the energy consumption and the time duration of two
computationally intensive representative applications: (i) RSA key generation
and encryption, and (ii) gaming/puzzles. We show that when the helper device is
more powerful than the device offloading the computations, the execution time
of the tasks is reduced. Finally, we show that devices that offload application
parts considerably reduce their energy consumption due to the low-power NFC
interface and the benefits of offloading.Comment: 9 pages, 4 tables, 13 figure
Modelling Chinese Smart Grid: A Stochastic Model Checking Case Study
Cyber-physical systems integrate information and communication technology
functions to the physical elements of a system for monitoring and controlling
purposes. The conversion of traditional power grid into a smart grid, a
fundamental example of a cyber-physical system, raises a number of issues that
require novel methods and applications. In this context, an important issue is
the verification of certain quantitative properties of the system. In this
technical report, we consider a specific Chinese Smart Grid implementation and
try to address the verification problem for certain quantitative properties
including performance and battery consumption. We employ stochastic model
checking approach and present our modelling and analysis study using PRISM
model checker
A performance study of routing protocols for mobile grid environment
Integration of mobile wireless consumer devices into the Grid initially seems unlikely due to limitation such as CPU performance,small secondary storage, heightened battery consumption sensitivity and unreliable low-bandwidth communication. The current grid architecture and algorithm also do not take into account the mobile computing environment since mobile devices have not been seriously considered as valid computing resources or interfaces in grid communities. This paper presents the results
of simulation done in identifying a suitable ad hoc routing
protocol that can be used for the target grid application in mobile environment. The simulation comparing three ad hoc routing protocols named DSDV, DSR and AODV
Design and evaluation of a DASH-compliant second screen video player for live events in mobile scenarios
The huge diffusion of mobile devices is rapidly changing the way multimedia content is consumed. Mobile devices are often used as a second screen, providing complementary information on the content shown on the primary screen, as different camera angles in case of a sport event. The introduction of multiple camera angles poses many challenges with respect to guaranteeing a high Quality of Experience to the end user, especially when the live aspect, different devices and highly variable network conditions typical of mobile environments come into play. Due to the ability of HTTP Adaptive Streaming (HAS) protocols to dynamically adapt to bandwidth fluctuations, they are especially suited for the delivery of multimedia content in mobile environments. In HAS, each video is temporally segmented and stored in different quality levels. Rate adaptation heuristics, deployed at the video player, allow the most appropriate quality level to be dynamically requested, based on the current network conditions. Recently, a standardized solution has been proposed by the MPEG consortium, called Dynamic Adaptive Streaming over HTTP (DASH). We present in this paper a DASH-compliant iOS video player designed to support research on rate adaptation heuristics for live second screen scenarios in mobile environments. The video player allows to monitor the battery consumption and CPU usage of the mobile device and to provide this information to the heuristic. Live and Video-on-Demand streaming scenarios and real-time multi-video switching are supported as well. Quantitative results based on real 3G traces are reported on how the developed prototype has been used to benchmark two existing heuristics and to analyse the main aspects affecting battery lifetime in mobile video streaming
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