41,397 research outputs found
AWARE: Platform for Autonomous self-deploying and operation of Wireless sensor-actuator networks cooperating with unmanned AeRial vehiclEs
This paper presents the AWARE platform that seeks to enable the cooperation of autonomous aerial vehicles with ground wireless sensor-actuator networks comprising both static and mobile nodes carried by vehicles or people. Particularly, the paper presents the middleware, the wireless sensor network, the node deployment by means of an autonomous helicopter, and the surveillance and tracking functionalities of the platform. Furthermore, the paper presents the first general experiments of the AWARE project that took place in March 2007 with the assistance of the Seville fire brigades
Energy Harvesting and Management for Wireless Autonomous Sensors
Wireless autonomous sensors that harvest ambient energy are attractive solutions, due to their convenience and economic benefits. A number of wireless autonomous sensor platforms which consume less than 100?W under duty-cycled operation are available. Energy harvesting technology (including photovoltaics, vibration harvesters, and thermoelectrics) can be used to power autonomous sensors. A developed system is presented that uses a photovoltaic module to efficiently charge a supercapacitor, which in turn provides energy to a microcontroller-based autonomous sensing platform. The embedded software on the node is structured around a framework in which equal precedent is given to each aspect of the sensor node through the inclusion of distinct software stacks for energy management and sensor processing. This promotes structured and modular design, allowing for efficient code reuse and encourages the standardisation of interchangeable protocols
An Energy Aware and Secure MAC Protocol for Tackling Denial of Sleep Attacks in Wireless Sensor Networks
Wireless sensor networks which form part of the core for the Internet of Things consist of resource constrained sensors that are usually powered by batteries. Therefore, careful
energy awareness is essential when working with these devices.
Indeed,the introduction of security techniques such as authentication and encryption, to ensure confidentiality and integrity of data, can place higher energy load on the sensors. However, the absence of security protection c ould give room for energy drain attacks such as denial of sleep attacks which have a higher negative impact on the life span ( of the sensors than the presence of security features.
This thesis, therefore, focuses on tackling denial of sleep attacks from two perspectives A security perspective and an energy efficiency perspective. The security perspective involves evaluating and ranking a number of security based techniques to curbing denial of sleep attacks. The energy efficiency perspective, on the other hand, involves exploring duty cycling and simulating three Media Access Control ( protocols Sensor MAC, Timeout MAC andTunableMAC under different network sizes and measuring different parameters such as the Received Signal Strength RSSI) and Link Quality Indicator ( Transmit power, throughput and energy efficiency Duty cycling happens to be one of the major techniques for conserving energy in wireless sensor networks and this research aims to answer questions with regards to the effect of duty cycles on the energy efficiency as well as the throughput of three duty cycle protocols Sensor MAC ( Timeout MAC ( and TunableMAC in addition to creating a novel MAC protocol that is also more resilient to denial of sleep a ttacks than existing protocols.
The main contributions to knowledge from this thesis are the developed framework used for evaluation of existing denial of sleep attack solutions and the algorithms which fuel the other contribution to knowledge a newly developed protocol tested on the Castalia Simulator on the OMNET++ platform. The new protocol has been compared with existing protocols and
has been found to have significant improvement in energy efficiency and also better resilience to denial of sleep at tacks Part of this research has been published Two conference
publications in IEEE Explore and one workshop paper
Flexible Integration of Alternative Energy Sources for Autonomous Sensing
Recent developments in energy harvesting and autonomous sensing mean that it is now possible to power sensors solely from energy harvested from the environment. Clearly this is dependent on sufficient environmental energy being present. The range of feasible environments for operation can be extended by combining multiple energy sources on a sensor node. The effective monitoring of their energy resources is also important to deliver sustained and effective operation. This paper outlines the issues concerned with combining and managing multiple energy sources on sensor nodes. This problem is approached from both a hardware and embedded software viewpoint. A complete system is described in which energy is harvested from both light and vibration, stored in a common energy store, and interrogated and managed by the node
Monitoring of gas emissions at landfill sites using autonomous gas sensors
Executive Summary
This report details the work carried out during the Smart
Plant project (2005-AIC-MS-43-M4). As part of this
research, an autonomous platform for monitoring
greenhouse gases (methane (CH4), carbon dioxide
(CO2)) has been developed, prototyped and field
validated. The modular design employed means that the
platform can be readily adapted for a variety of
applications involving these and other target gases such
as hydrogen sulfide (H2S), ammonia (NH3) and carbon
monoxide (CO) and the authors are in the process of
completing several short demonstrator projects to
illustrate the potential of the platform for some of these
applications. The field validation for the greenhouse gas
monitoring platform was carried out at two landfill sites in
Ireland. The unit was used to monitor the concentration of
CO2 and CH4 gas at perimeter borehole wells. The final
prototype was deployed for over 4 months and
successfully extracted samples from the assigned
perimeter borehole well headspace, measured them and
sent the data to a database via a global system for mobile
(GSM) communications. The data were represented via
an updating graph in a web interface. Sampling was
carried out twice per day, giving a 60-fold increase on
current monitoring procedures which provide one gas
concentration measurement per month.
From additional work described in this report, a
number of conclusions were drawn regarding lateral
landfill gas migration on a landfill site and the
management of this migration to the site’s perimeter.
To provide frequent, reliable monitoring of landfill gas
migration to perimeter borehole wells, the unit needs
to:
• Be fully autonomous;
• Be capable of extracting a gas sample from a
borehole well independently of personnel;
• Be able to relay the data in near real time to a base
station; and
• Have sensors with a range capable of adequately
monitoring gas events accurately at all times.
The authors believe that a unit capable of such
monitoring has been developed and validated. This
unit provides a powerful tool for effective management
of landfill site gases. The effectiveness of this unit has
been recognised by the site management team at the
long-term deployment trial site, and the data gathered
have been used to improve the day-to-day operations
and gas management system on-site.
The authors make the following recommendations:
1. The dynamics of the landfill gas management
system cannot be captured by taking
measurements once per month; thus, a minimum
sampling rate of once per day is advised.
2. The sampling protocol should be changed:
(i) Borehole well samples should not be taken
from the top of the well but should be
extracted at a depth within the headspace
(0.5–1.0 m). The measurement depth will be
dependent on the water table and headspace
depth within the borehole well.
(ii) The sampling time should be increased to 3
min to obtain a steady-state measurement
from the headspace and to take a
representative sample; and
(iii) For continuous monitoring on-site, the
extracted sample should be recycled back
into the borehole well. However, for
compliance monitoring, the sample should
not be returned to the borehole well.
3. Devices should be placed at all borehole wells so
the balance on the site can be maintained through
the gas management system and extraction
issues can be quickly recognised and addressed
before there are events of high gas migration to
the perimeter.
4. A pilot study should be carried out by the EPA
using 10 of these autonomous devices over three
to five sites to show the need and value for this
type of sampling on Irish landfill sites
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