26,438 research outputs found
Network-aware design-space exploration of a power-efficient embedded application
The paper presents the design and multi-parameter optimization of a networked embedded application for the health-care domain. Several hardware, software, and application parameters, such as clock frequency, sensor sampling rate, data packet rate, are tuned at design- and run-time according to application specifications and operating conditions to optimize hardware requirements, packet loss, power consumption. Experimental results show that further power efficiency can be achieved by considering also communication aspects during design space exploratio
Reporting an Experience on Design and Implementation of e-Health Systems on Azure Cloud
Electronic Health (e-Health) technology has brought the world with
significant transformation from traditional paper-based medical practice to
Information and Communication Technologies (ICT)-based systems for automatic
management (storage, processing, and archiving) of information. Traditionally
e-Health systems have been designed to operate within stovepipes on dedicated
networks, physical computers, and locally managed software platforms that make
it susceptible to many serious limitations including: 1) lack of on-demand
scalability during critical situations; 2) high administrative overheads and
costs; and 3) in-efficient resource utilization and energy consumption due to
lack of automation. In this paper, we present an approach to migrate the ICT
systems in the e-Health sector from traditional in-house Client/Server (C/S)
architecture to the virtualised cloud computing environment. To this end, we
developed two cloud-based e-Health applications (Medical Practice Management
System and Telemedicine Practice System) for demonstrating how cloud services
can be leveraged for developing and deploying such applications. The Windows
Azure cloud computing platform is selected as an example public cloud platform
for our study. We conducted several performance evaluation experiments to
understand the Quality Service (QoS) tradeoffs of our applications under
variable workload on Azure.Comment: Submitted to third IEEE International Conference on Cloud and Green
Computing (CGC 2013
Concurrent Backscatter Streaming from Batteryless and Wireless Sensor Tags with Multiple Subcarrier Multiple Access
This paper proposes a novel multiple access method that enables concurrent sensor data streaming from multiple batteryless, wireless sensor tags. The access method is a pseudo-FDMA scheme based on the subcarrier backscatter communication principle, which is widely employed in passive RFID and radar systems. Concurrency is realized by assigning a dedicated subcarrier to each sensor tag and letting all sensor tags backscatter simultaneously. Because of the nature of the subcarrier, which is produced by constant rate switching of antenna impedance without any channel filter in the sensor tag, the tag-to-reader link always exhibits harmonics. Thus, it is important to reject harmonics when concurrent data streaming is required. This paper proposes a harmonics rejecting receiver to allow simultaneous multiple subcarrier usage. This paper particularly focuses on analog sensor data streaming which minimizes the functional requirements on the sensor tag and frequency bandwidth. The harmonics rejection receiver is realized by carefully handling group delay and phase delay of the subcarrier envelope and the carrier signal to accurately produce replica of the harmonics by introducing Hilbert and inverse Hilbert transformations. A numerical simulator with Simulink and a hardware implementation with USRP and LabVIEW have been developed. Simulations and experiments reveal that even if the CIR before harmonics rejection is 0dB, the proposed receiver recovers the original sensor data with over 0.98 cross-correlation
Complex Actions for Event Processing
Automatic reactions triggered by complex events have been
deployed with great success in particular domains, among
others, in algorithmic trading, the automatic reaction to realtime
analysis of marked data. However, to date, reactions
in complex event processing systems are often still limited
to mere modifications of internal databases or are realized
by means similar to remote procedure calls.
In this paper, we argue that expressive complex actions
with support for composite work
ows and integration of
so called external actions are desirable for a wide range
of real-world applications among other emergency management.
This article investigates the particularities of external
actions needed in emergency management, which are initiated
inside the event processing system but which are actually
executed by external actuators, and discuss the implications
of these particularities on composite actions. Based
on these observations, we propose versatile complex actions
with temporal dependencies and a seamless integration of
complex events and external actions. This article also investigates
how the proposed integrated approach towards
complex events and complex actions can be evaluated based
on simple reactive rules. Finally, it is shown how complex actions
can be deployed for a complex event processing system
devoted to emergency management
Extrinsic Parameter Calibration for Line Scanning Cameras on Ground Vehicles with Navigation Systems Using a Calibration Pattern
Line scanning cameras, which capture only a single line of pixels, have been
increasingly used in ground based mobile or robotic platforms. In applications
where it is advantageous to directly georeference the camera data to world
coordinates, an accurate estimate of the camera's 6D pose is required. This
paper focuses on the common case where a mobile platform is equipped with a
rigidly mounted line scanning camera, whose pose is unknown, and a navigation
system providing vehicle body pose estimates. We propose a novel method that
estimates the camera's pose relative to the navigation system. The approach
involves imaging and manually labelling a calibration pattern with distinctly
identifiable points, triangulating these points from camera and navigation
system data and reprojecting them in order to compute a likelihood, which is
maximised to estimate the 6D camera pose. Additionally, a Markov Chain Monte
Carlo (MCMC) algorithm is used to estimate the uncertainty of the offset.
Tested on two different platforms, the method was able to estimate the pose to
within 0.06 m / 1.05 and 0.18 m / 2.39. We also propose
several approaches to displaying and interpreting the 6D results in a human
readable way.Comment: Published in MDPI Sensors, 30 October 201
Rational physical agent reasoning beyond logic
The paper addresses the problem of defining a theoretical physical agent framework that satisfies practical requirements of programmability by non-programmer engineers and at the same time permitting fast realtime operation of agents on digital computer networks. The objective of the new framework is to enable the satisfaction of performance requirements on autonomous vehicles and robots in space exploration, deep underwater exploration, defense reconnaissance, automated manufacturing and household automation
SystemC Model Generation for Realistic Simulation of Networked Embedded Systems
Verification and design-space exploration of today's embedded systems require the simulation of heterogeneous aspects of the system, i.e., software, hardware, communications. This work shows the use of SystemC to simulate a model-driven specification of the behavior of a networked embedded system together with a complete network scenario consisting of the radio channel, the IEEE 802.15.4 protocol for wireless personal area networks and concurrent traffic sharing the medium. The paper describes the main issues addressed to generate SystemC modules from Matlab/Stateflow descriptions and to integrate them in a complete network scenario. Simulation results on a healthcare wireless sensor network show the validity of the approach
Modelling and Simulation of Asynchronous Real-Time Systems using Timed Rebeca
In this paper we propose an extension of the Rebeca language that can be used
to model distributed and asynchronous systems with timing constraints. We
provide the formal semantics of the language using Structural Operational
Semantics, and show its expressiveness by means of examples. We developed a
tool for automated translation from timed Rebeca to the Erlang language, which
provides a first implementation of timed Rebeca. We can use the tool to set the
parameters of timed Rebeca models, which represent the environment and
component variables, and use McErlang to run multiple simulations for different
settings. Timed Rebeca restricts the modeller to a pure asynchronous
actor-based paradigm, where the structure of the model represents the service
oriented architecture, while the computational model matches the network
infrastructure. Simulation is shown to be an effective analysis support,
specially where model checking faces almost immediate state explosion in an
asynchronous setting.Comment: In Proceedings FOCLASA 2011, arXiv:1107.584
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