Now showing 1 - 10 of 26
  • Publication
    Evaluation of energy-efficiency in lighting systems using sensor networks
    In modern energy aware buildings, lighting control systems are put in place so to maximise the energy-efficiency of the lighting system without effecting the comfort of the occupant. In many cases this involves utilising a set of presence sensors, with actuators, to determine when to turn on/off or dim lighting, when it is deemed necessary. Such systems are installed using standard tuning values statically fixed by the system installer. This can cause inefficiencies and energy wastage as the control system is never optimised to its surrounding environment. In this paper, we investigate a Wireless Sensor Network (WSN) as a viable tool that can help in analysing and evaluating the energy-efficiency of an existing lighting control system in a low-cost and portable solution. We introduce LightWiSe (LIGHTting evaluation through WIreless SEnsors), a wireless tool which aims to evaluate lighting control systems in existing office buildings. LightWiSe determines points in the control system that exhibit energy wastage and to highlight areas that can be optimised to gain a greater efficiency in the system. It will also evaluate the effective energy saving to be obtained by replacing the control system with a more judicious energy saving solution. During a test performed in an office space, with a number of different lighting control systems we could highlight a number of areas to reduce waste and save energy. Our findings show that each system tested can be optimised to achieve greater efficiency. LightWiSe can highlight savings in the region of 50% to 70% that are achievable through optimising the current control system or installing an alternative.
  • Publication
    Managing mobile-based participatory sensing communities
    Participation of mobile phone users in sensorial data collection both from the individual and from the surrounding environment presents a wide range of opportunities for truly pervasive applications. This paper highlights relevant issues related to mobile-phone participatory sensing and describes an architecture framework to flexibly create new communities of data interest, to manage and interact with those communities and to finally provide useful information to the users.
  • Publication
    Dynamic reassignment of aggregation point for network load balancing
    Some wireless sensor network applications forward data to a central aggregation point (AP) that is responsible for processing, aggregating, and relaying information to the base station. For example one node in a body sensor network is responsible for aggregating data and then forwarding only useful information to an external ambient network. This procedure leads to asymmetry in the AP node energy consumption due to (1) higher forwarding activity for nodes in the vicinity of the AP and (2) higher AP activity relative to nodes. Existing approaches of load and energy consumption balancing employ either suboptimal periodical route changes or random AP rotations. In contrast, we propose a novel technique1 to enable a dynamic reassignment of the sensor AP according to a novel cost function that is based on relevant node energy metrics. We show that the technique lead to a network lifetime extension up to 50% for applications, such as medical, that require power-intensive tasks at the AP and for high traffic applications.
  • Publication
    A Methodology for the development of multi-agent systems on wireless sensor networks
    Recent technological advances in wireless networking, IC fabrication and sensor technology have lead to the emergence of millimeter scale devices that collectively form a Wireless Sensor Network (WSN). The cost of production for a single node has been reduced to less than 1 dollar, paving the way for large scale deployments (millions of nodes per network) of such devices. It would seem that agent technology should be useful for these highly distributed networks in terms of intelligent network management and data harvesting for example. Indeed this has been shown to be the case, however multi-agent systems for WSNs are scarce. One reason for this is the difficulty in the deployment, testing and debugging of a distributed application for these devices due to the minimal (if any) user interfaces they possess. In this paper we will propose a methodology for the rapid development of a MAS for WSNs that allows for comprehensive testing and debugging, a luxury not available on current WSN devices. We also instantiate this methodology in a case study for evaluation purposes.
  • Publication
    On the RFID Wake-up Impulse for Multi-hop Sensor Networks
    Communication protocols for wireless sensor networks reduce the energy consumption by duty cycling the node activity and adopting a periodic sleeping scheduling. This approach often results in idle listening and therefore energy dissipated for listening to a channel free from packet transmitted. Duty cycling trades-off energy consumption due to idle listening and high end-to-end delay. Proposed solutions mitigate this issue for example through extra low-power radio components (wake-up radio) that listen to the radio and wake-up the node if some channel activity is sensed. These extra components also consume some energy to listen to the channel. In contrast, we propose an on-demand wake-up capability, namely RFIDimpulse, which is achieved through using an off-the-shelf batteryless RFID tag attached to each sensor node that is also provided with RFID reader capability. Because modern RFID techniques can trigger all the neighbouring tags at once or pinpoint a particular tag, RFIDimpluse provides both unicast and multicast capability. RFIDimpulse allows eventdriven communication and eliminates node idle listening.
  • Publication
    Diversity & interoperability : wireless technologies in ambient assisted living
    Ambient Assisted Living (AAL) demands the seamless integration of a range of technologies such that the particular needs of the elderly may be met. Given the heterogeneity of the elderly population, in their needs and circumstances amongst others, this is a significant challenge. In essence, it demands that a disparate suite of technologies be deployed, integrated, managed and interacted with in a seamless and intuitive fashion. In this paper, how this heterogeneity may be managed is discussed. In particular, the use of ontologies and middleware are proposed as potential solutions to this heterogeneity problem.
  • Publication
    COPOLAN : non-invasive occupancy profiling for preliminary assessment of HVAC fixed timing strategies
    Nowadays, control of heating, cooling and ventilation equipment operation is mainly achieved via timers with fixed setback schedules, configured using experience and standard models of space occupancy. Applying generic timing strategies is however rarely optimal. Sensor-based systems offer a solution for dynamic control of equipment operation using real-time space occupancy input, but both deployment time and cost constraints hinder their integration if savings and return on investment are uncertain. This work introduces COPOLAN, a tool that correlates power consumption pat- terns and computers’ VLAN activity. Utilising computers’ VLAN activity auditing is key to obtain the power state of employees’ computer equipment over time, a prime indicator of employees’ presence within a building. At low cost and non-invasively, COPOLAN uncovers misalignment and pro- duces ground for (1) determining opportunities of improv- ing HVAC timing strategies and (2) helping decision making prior to integrating new equipment such as sensor-based systems. COPOLAN has been experimented on within a University department, where misalignment between power consumption and space occupancy patterns have highlighted 10 % energy saving opportunities.
      690Scopus© Citations 12
  • Publication
    Embedding intelligent decision making within complex dynamic environments
    Decision-making is a complex and demanding process often constrained in a number of possibly conflicting dimensions including quality, responsiveness and cost. This paper considers in situ decision making whereby decisions are effected based upon inferences made from both locally sensed data and data aggregated from a sensor network. Such sensing devices that comprise a sensor network are often computationally challenged and present an additional constraint upon the reasoning process. This paper describes a hybrid reasoning approach to deliver in situ decision making which combines stream based computing with multi-agent system techniques. This approach is illustrated and exercised through an environmental demonstrator project entitled SmartBay which seeks to deliver in situ real time environmental monitoring.
      1234Scopus© Citations 12
  • Publication
    Radio Sleep Mode Optimization in Wireless Sensor Networks
    Energy efficiency is a central challenge in sensor networks, and the radio is a major contributor to overall energy node consumption. Current energy-efficient MAC protocols for sensor networks use a fixed low-power radio mode for putting the radio to sleep. Fixed low-power modes involve an inherent trade-off: deep sleep modes have low current draw and high energy cost and latency for switching the radio to active mode, while light sleep modes have quick and inexpensive switching to active mode with a higher current draw. This paper proposes adaptive radio low-power sleep modes based on current traffic conditions in the network. It first introduces a comprehensive node energy model, which includes energy components for radio switching, transmission, reception, listening, and sleeping, as well as the often disregarded microcontroller energy component for determining the optimal sleep mode and MAC protocol to use for given traffic scenarios. The model is then used for evaluating the energy-related performance of our recently proposed RFIDImpulse protocol enhanced with adaptive low-power modes, and comparing it against BMAC and IEEE 802.15.4, for both MicaZ and TelosB platforms under varying data rates. The comparative analysis confirms that RFIDImpulse with adaptive low-power modes provides up to 20 times lower energy consumption than IEEE 802.15.4 in low traffic scenario. The evaluation also yields the optimal settings of low-power modes on the basis of data rates for each node platform, and provides guidelines and a simple algorithm for the selection of appropriate MAC protocol, low-power mode, and node platform for a given set of traffic requirements of a sensor network application.
      1071Scopus© Citations 121
  • Publication
    The clarity modular ambient health and wellness measurement platform
    Emerging healthcare applications can benefit enormously from recent advances in pervasive technology and computing. This paper introduces the CLARITY Modular Ambient Health and Wellness Measurement Platform, which is a heterogeneous and robust pervasive healthcare solution currently under development at the CLARITY Center for Sensor Web Technologies. This intelligent and context-aware platform comprises the Tyndall Wireless Sensor Network prototyping system, augmented with an agent-based middleware and frontend computing architecture. The key contribution of this work is to highlight how interoperability, expandability, reusability and robustness can be manifested in the modular design of the constituent nodes and the inherently distributed nature of the controlling software architecture.
      777Scopus© Citations 5