Graeme M. Bragg

A geophone wireless sensor network for investigating glacier stick-slip motion

We have developed an innovative passive borehole geophone system, as part of a wireless environmental sensor network to investigate glacier stick-slip motion. The new geophone nodes use an ARM Cortex-M3 processor with a low power design capable of running on battery power while embedded in the ice. Only data from seismic events was stored, held temporarily on a micro-SD card until they were retrieved by systems on the glacier surface which are connected to the internet. The sampling rates, detection and filtering levels were determined from a field trial using a standard commercial passive seismic system. The new system was installed on the Skalafellsjokull glacier in Iceland and provided encouraging results. The results showed that there was a relationship between surface melt water production and seismic event (ice quakes), and these occurred on a pattern related to the glacier surface melt-water controlled velocity changes (stick-slip motion). Three types of seismic events were identified, which were interpreted to reflect a pattern of till deformation (Type A), basal sliding (Type B) and hydraulic transience (Type C) associated with stick-slip motion.

868MHz 6LoWPAN with ContikiMAC for an internet of things environmental sensor network

When deploying an Internet of Things Environmental Sensor Network (ESN), the communications range of nodes becomes a critical factor when attempting to cover a large geographic area. The 2.4 GHz radios that are commonly used for Wireless Sensor Networks do not have sufficient range for ESN applications. We investigate the performance of an 868MHz CC1120-based sensor node that incorporates a Zolertia Z1 and runs the Contiki operating system with multi-hop 6LoWPAN networking using the ContikiMAC radio duty cycling protocol. Comparisons with the commonly-used CC2420 2.4GHz radio, in terms of latency and throughput, show that the CC1120 can offer significant performance benefits for certain deployment scenarios. Brief details of an ongoing deployment are presented.

Dataset for Application Control and Monitoring in Heterogeneous Multiprocessor Systems

Dataset supports: Leech, C. et al (2018) Application Control and Monitoring in Heterogeneous Multiprocessor Systems. 13th International Symposium on Reconfigurable Communication-centric Systems-on-Chip (ReCoSoC)

Dataset for An Application- and Platform-agnostic Control and Monitoring Framework for Multicore Systems

Dataset supports: Bragg, G. M. et al (2018) An Application- and Platform-agnostic Control and Monitoring Framework for Multicore Systems. 3rd International Conference on Pervasive and Embedded Computing (PEC).

Hardware and software innovations in energy-efficient system-reliability monitoring

Many threats that can undermine the reliability of a system can be realized at design, while others only during its online operation. As the availability of system monitoring sensors and run-time software increases in heterogeneous platforms, there is a demand for a novel platform-independent framework that can capture and deliver, in a holistic way, system level self-assessment and adaptation capabilities at run-time. In this paper, two groups from academia and one from industry present the following three contributions. First, system reliability is considered from the perspective of novel timing guardband designs for aging mitigation. Effective timing guardband models are presented from the physical to the system level, while targeting multiple wear-out mechanisms. Second, a technique for correlating complex software and micro-architectural events with power integrity loss is presented. The presented technique uses an embedded voltage noise sensor, a power-network model and a genetic algorithm for identifying workload that triggers power-network resonances which can ultimately lead to system failures. Third, the ‘PRiME’ cross-layer programming framework is presented that unites available sensors and dynamic-voltage and frequency scaling actuators with learning-based run-time process mapping and scheduling algorithms. Scenarios on exploring the energy efficiency and reliability of heterogeneous platforms using run-time software derived from the developed framework are also reviewed.

Deploying a 6LoWPAN, CoAP, low power, wireless sensor network: Poster Abstract

In order to integrate equipment from different vendors, wireless sensor networks need to become more standardized. Using IP as the basis of low power radio networks, together with application layer standards designed for this purpose is one way forward. This research focuses on implementing and deploying a system using Contiki, 6LoWPAN over an 868 MHz radio network, together with CoAP as a standard application layer protocol. A system was deployed in the Cairngorm mountains in Scotland as an environmental sensor network, measuring streams, temperature profiles in peat and periglacial features. It was found that RPL provided an effective routing algorithm, and that the use of UDP packets with CoAP proved to be an energy efficient application layer. This combination of technologies can be very effective in large area sensor networks.In order to integrate equipment from different vendors, wireless sensor networks need to become more standardized. Using IP as the basis of low power radio networks, together with application layer standards designed for this purpose is one way forward. This research focuses on implementing and deploying a system using Contiki, 6LoWPAN over an 868 MHz radio network, together with CoAP as a standard application layer protocol. A system was deployed in the Cairngorm mountains in Scotland as an environmental sensor network, measuring streams, temperature profiles in peat and periglacial features. It was found that RPL provided an effective routing algorithm, and that the use of UDP packets with CoAP proved to be an energy efficient application layer. This combination of technologies can be very effective in large area sensor networks.