Now showing 1 - 3 of 3
  • Publication
    Portability versus effciency tradeoffs in MAC implementations for microsensor platforms
    Abstract—Medium Access Control (MAC) implementations control access of network devices to a transmission medium. For emerging communication protocols, the MAC is typically implemented in software, to enable adaptation to evolving defacto or industry standards. Software MAC implementations are typically realized as state machines, executing code related to successive MAC states within periodic interrupts. This software construct yields minimal memory footprint and energy efficiency, but the resulting implementations are often tightly coupled to the platform’s system software, and are thus non-portable across hardware and system platforms. This article presents an architecture that decouples MAC and system software, enabling portability, while preserving software efficiency.
      1065Scopus© Citations 1
  • 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.
    Scopus© Citations 12  837
  • Publication
    Portability in MAC protocol and transceiver software implementations for LR-WPAN platforms
    In a variety of emerging networked computing system domains over the years, there have been bursts of activity on new medium access control (MAC) protocols, as new communication transceiver technologies with greater data-movement performance or lower power dissipation have been introduced. To enable implementations flexible to evolving standards and improving application-domain insight, such MAC protocols are typically initially implemented in software, and interface between applications or system software, typically executing on an embedded processor or microcontroller, and the evolving radio transceiver hardware. Many challenges exist in implementing MAC protocols across evolving or competing transceiver hardware implementations and processor architectures. Some of these challenges are peculiar to the requirements of MAC protocols, and others are a result of the plethora of system and processor architectures in the embedded systems domain. This article studies the challenges facing software implementations of MAC protocols running on embedded microcontrollers, and interfacing with radio transceiver hardware. Experience with an implementation of the IEEE 802.15.4 MAC across three hardware platforms with different processor, system, and systems software architectures is presented, focusing on implementation approach and interfaces. Pitfalls are pointed out, and guidelines are provided for ensuring that new MAC implementations are easily portable across processor architectures and transceiver hardware.
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