Greg P Timms

Greg P Timms
The Commonwealth Scientific and Industrial Research Organisation | CSIRO · Data61

B.Sc. (Hons) Ph.D.

About

53
Publications
8,159
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565
Citations
Citations since 2017
3 Research Items
315 Citations
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20172018201920202021202220230204060
20172018201920202021202220230204060

Publications

Publications (53)
Article
Full-text available
This paper proposes a method to design the deployment of sensor nodes in a new region where historical data is not available. A number of mobile platforms are simulated to build initial knowledge of the region. Further, an evolutionary algorithm is employed to find the optimum placement of a given number of sensor nodes that best represents the reg...
Article
Full-text available
This paper presents an approach to the design of Environmental Sensor Networks (ESN) which aims at providing a robust, fit-for-purpose network with minimum redundancy. A set of near optimum ESN designs is sought using an Evolutionary Algorithm, which incorporates redundancy and robustness as fitness functions. This work can assist the decision maki...
Article
For remote characterization of inaccessible underground mine voids, we are developing unmanned aerial vehicles (equipped with multiple sensors, including cameras) to fly into the mine voids to map their shape, condition, and most importantly, mineralization of the surface. The X-ray fluorescence (XRF) spectroscopy analysis is normally conducted on...
Conference Paper
Many underground mine void spaces are not suitable for human entry due to unprotected roofs, instability or having an unknown safety state (eg if they are many decades old). Investigations of these voids may nevertheless be important for general mine safety, for example to detect propagating collapses or water accumulation, prevent accidental intru...
Article
In this paper various supervised machine learning techniques were applied to classify cattle behaviour patterns recorded using collar systems with 3-axis accelerometer and magnetometer, fitted to individual dairy cows to infer their physical behaviours. Cattle collar data was collected at the Tasmanian Institute of Agriculture (TIA) Dairy Research...
Article
Full-text available
This work proposes the design of Environmental Sensor Networks (ESN) through balancing robustness and redundancy. An Evolutionary Algorithm (EA) is employed to find the optimal placement of sensor nodes in the Region of Interest (RoI). Data quality issues are introduced to simulate their impact on the performance of the ESN. Spatial Regression Test...
Article
In this paper, two new multivariate time series classifiers are introduced as the Bag of Class Posteriors (BOCP) and the Bag of Class Posterior with Ordering (BOCPO). The models propose a new multi-scale feature representation where the class posterior estimates of contiguous local patterns are aggregated over longer time scales. The models are emp...
Article
Spatially distributed regions may have different influences that affect the underlying physical processes and make it inappropriate to directly relocate learned models. We may also be aiming to detect rare events for which we have examples in some regions, but not others. Three novel voting methods are presented for combining classifiers trained on...
Article
Full-text available
Shellfish farms are closed for harvest when microbial pollutants are present. Such pollutants are typically present in rainfall runoff from various land uses in catchments. Experts currently use a number of observable parameters (river flow, rainfall, salinity) as proxies to determine when to close farms. We have proposed using the short term histo...
Article
A novel machine learning approach to assess the quality of sensor data using an ensemble classification framework is presented in this paper. The quality of sensor data is indicated by discrete quality flags that indicate the level of uncertainty associated with a sensor reading. Depending on the domain and the problem under consideration, the leve...
Article
Full-text available
The National Reference Station (NRS) network, part of Australia’s Integrated Marine Observing System (IMOS), is designed to provide the baseline multi-decadal time series required to understand how large-scale, long-term change and variability in the global ocean are affecting Australia’s coastal ocean ecosystems. High temporal resolution observati...
Conference Paper
This research study focused on automatic sensor data annotation and visualisation of dynamic weather data acquired from a large sensor network. The aim was to develop a data visualisation method for CSIRO's South Esk hydrological sensor web to evaluate the overall network performance and provide visual data quality assessment. The visual data quali...
Conference Paper
Shellfish farms need to be closed from harvesting when the water body is contaminated to avoid a serious health hazard. We have designed a sensor network framework to monitor a number of water quality variables to check the health of shellfish farms and predict closure if hazardous. Because of the uncertainty associated with the data acquisition pr...
Conference Paper
Numerous sources of uncertainty are associated with the data acquisition process in marine sensor networks. It is thus required to assure that the data quality of sensors is fit for the intended purpose. We propose a supervised learning framework to infer the quality of sensor observations online. A problem with using supervised classification in q...
Article
Full-text available
Online automated quality assessment is critical to determine a sensor's fitness for purpose in real-time applications. A Dynamic Bayesian Network (DBN) framework is proposed to produce probabilistic quality assessments and represent the uncertainty of sequentially correlated sensor readings. This is a novel framework to represent the causes, qualit...
Conference Paper
Research is being conducted into performing chemical analysis of marine sediments in situ using an Autonomous Underwater Vehicle (AUV) equipped with an X-ray Fluorescence (XRF) spectrometer and X-ray tube. This is for the purpose of identifying regions of high heavy metal concentrations. A housing has been designed to safely attach the XRF system t...
Article
We describe the design and application of a system for measuring the magnitude and phase of antenna radiation patterns in the 182-194 GHz frequency range. A heterodyne receiver comparing antenna and reference signals is designed from readily available components and incorporated into a 12-m anechoic chamber. The chamber is used with or without a co...
Article
As many sensor networks are currently being deployed for environmental monitoring, there is a growing need to develop systems and applications for managing, processing and retrieving massive amounts of data generated from those networks. In this research, a query answering system with pattern mining techniques is investigated specifically for marin...
Article
Full-text available
The automated collection of data (e.g., through sensor networks) has led to a massive increase in the quantity of environmental and other data available. The sheer quantity of data and growing need for real-time ingestion of sensor data (e.g., alerts and forecasts from physical models) means that automated Quality Assurance/Quality Control (QA/QC)...
Article
Full-text available
We review existing query answering systems for sensor data. We then propose an extended query answering approach termed smart query, specifically for marine sensor data. The smart query answering system integrates pattern queries and continuous queries. The proposed smart query system considers both streaming data and historical data from marine se...
Conference Paper
An integrated pattern mining technique for query answering is proposed for marine sensor data. In pattern query, we adopt the dynamic time warping (DTW) method and propose the use of a query relaxation approach in finding similar patterns. We further calculate prediction from discovered similar patterns in marine sensor data. The predictive values...
Conference Paper
The National Reference Station (NRS) network, part of Australia's Integrated Marine Observing System (IMOS), is designed to provide the baseline multi decadal time series required to understand how large-scale, long-term change and variability in the global ocean are affecting Australia's coastal ocean ecosystems. High temporal resolution observati...
Conference Paper
The Tasmanian Marine Analysis Network (Tas-MAN) project has initiatives to reduce costs at every level of a marine sensor network; including hardware, deployment, maintenance, data management, and information delivery.
Article
We describe the design and measured performance of an improved beam-scanning fan-beam antenna suitable for mm wavelengths. The fan beam is scanned in the direction orthogonal to the fan and can be polarized either in or orthogonal to this direction. The pillbox design is improved by the introduction of a third cylindrical reflector and optimum shap...
Article
In order to optimise use of the limited resources (time, power) of an autonomous underwater vehicle (AUV) with a miniaturised X-ray fluorescence (XRF) spectrometer on board to carry out in situ autonomous chemical mapping of the surface of sediments with desired resolution, a genetic algorithm for rapid curve fitting is reported in this paper. This...
Article
The manual Quality Control (QC) process undertaken by experts in marine sensor deployments is becoming increasingly impractical as the size of these deployments increase and streaming applications become the norm. Automated quality control procedures have been developed for real-time sensor deployments proposing a range of tests and checks. Althoug...
Article
The Tasmanian Marine Analysis Network (Tas-MAN) project has initiatives to reduce costs at every level of a marine sensor network; including hardware, deployment, maintenance, data management, and information delivery.
Article
Full-text available
The National Reference Station (NRS) network, part of Australia's Integrated Marine Observing System (IMOS), is designed to provide the baseline multi decadal time series required to understand how large-scale, long-term change and variability in the global ocean are affecting Australia's coastal ocean ecosystems. High temporal resolution observati...
Article
The design and testing of an active 190-GHz imaging system is presented. The system features two beam-scanning antennas, one of which transmits a vertical fan beam, and the other which receives a horizontal fan beam. By correlating the transmitted and received signals, an output is obtained that is proportional to the millimeter-wave reflectivity a...
Conference Paper
The use a small and low-cost Autonomous Underwater Vehicle (AUV), developed at CSIRO, is proposed to record data between fixed sensors with the aim of providing data sufficient to improve our understanding of the spatial extent of phenomena like the pycnocline and the effect of wind on salinity and temperature is. We suggest the spatial gap between...
Conference Paper
Curve fitting of the measured spectrum in real time using genetic algorithms was performed to support the adaptive behaviour of an AUV equipped with an XRF. Preliminary results of the curve fitting algorithm are shown to demonstrate the algorithm using synthetic data sets.
Article
Full-text available
An Autonomous Underwater Vehicle (AUV) equipped with rare-earth (Sm-Co) magnets was used to sample suspended particles during its transects of the Derwent estuary in Tasmania. Mineral characterization was then performed in the laboratory using 57Fe Mössbauer spectroscopy (MB) and X-ray diffractometry (XRD). Results indicate the sources of the suspe...
Article
Inference on aspects influencing data quality should be based on or derived from experience. In this work we implement a Fuzzy Set Theory approach to provide an assessment of data quality from a near-real time marine sensor network. The Fuzzy System firstly captures tacit knowledge using membership functions, and then uses these membership function...
Conference Paper
We use an AUV, Starbug, to produce habitat maps by identifying benthos from their spectral signatures. This requires a measurement of the light attenuation in the water column at the current site. The study area usually contains two layers of water with distinct attenuation characteristics, which can vary substantially in response to events such as...
Conference Paper
The Tasmanian Marine Analysis Network (TasMAN) has been developed and deployed to help manage the multiple uses of the estuaries and coastal regions of southern Tasmania, Australia. These regions are used by industry, shipping, aquaculture and tourism operators along with commercial and recreational boaters and fishers. The network is designed to c...
Conference Paper
We provide an outline of an autonomous benthic habitat mapping algorithm. This algorithm enables real-time on-board classification of images gathered by an autonomous underwater vehicle (AUV), with the ability to classify aquatic vegetation at a resolution approaching the species level. The algorithm is generic with respect to both the classificati...
Conference Paper
The capability of millimetre-wave imaging systems to detect concealed weapons and explosives is of interest to government agencies and the security industry. These systems generally operate at frequencies of 35 and 94 GHZ but there are significant advantages in moving to higher frequencies; particularly the possibility of increasing stand-off dista...
Article
Two methods, the modulated scene method and modulated beam method, are proposed in this paper to manage the fringe in a T-shaped correlating millimeter-wave imaging system. The modulated scene method incorporates the fringe into the scene to form a fringe-modulated scene. The pencil beam that corresponds to the beam of the system with a zero baseli...
Article
The design and testing of a 190 GHz imaging system is presented. The system features two beam-scanning antennas; the first transmits a horizontal fan beam and the second receives a vertical fan beam. By correlating the signals from the antennas, an estimate of the millimeter-wave reflectivity at the intersection of the fan beams is obtained. Each f...
Article
A prototype cross-correlating 190 GHz passive mm-wave imaging system has been developed. This system is based on the Mills Cross system used for radio astronomical imaging. It uses two pillbox antennas arranged in a T configuration. Each antenna generates a fan beam and the two fan beams are orthogonal to each other. By cross-correlating signals re...
Article
The design and testing of a 190 GHz imaging system is presented. The system features two beam-scanning antennas; the first transmits a horizontal fan beam and the second receives a vertical fan beam. By correlating the signals from the antennas, an estimate of the millimeter-wave reflectivity at the intersection of the fan beams is obtained. Each f...
Conference Paper
The design and testing of a 190 GHz imaging system is presented. The system features two beam-scanning antennas; the first transmits a horizontal fan beam and the second receives a vertical fan beam. By correlating the signals from the antennas, an estimate of the millimeter-wave reflectivity at the intersection of the fan beams is obtained. Each f...
Article
Full-text available
Two studies of the outdoor propagation of 60 GHz microwaves aredescribed. The focus of this paper is the relationship between rainfalland measured attenuation of the microwave signal. Experimental data arepresented and the measured statistics are compared with theRecommendations of the ITU-R. Measured rain intensity statistics at thetwo sites were...
Article
The design and testing of a beam-scanning pillbox antenna for use in a 200 GHz imaging system is presented. The antenna features a rotating subreflector that scans the antenna's fan beam and a multimode structure that reduces ohmic loss and allows use of two orthogonal polarizations. The antenna has an aperture size of 450 $,times,$ 5 mm, half-powe...
Article
Gyrotron V, the latest University of Sydney gyrotron, is a source of millimeter waves tunable from 150 to 300 GHz when operating at the fundamental of the electron cyclotron frequency and from 300 to 600 GHz when operating at the second harmonic. Quasioptical antennas are used to direct this radiation into an oversized waveguide leading to the expe...
Article
In this letter the low temperature phase transitions in a compressed powder sample of thiourea, a ferroelectric, are studied at millimeter wavelengths by the reflection of a beam incident at an angle of 45°. The range of frequencies between 100 and 300 GHz was covered by an Impatt oscillator and a tunable gyrotron. The change in permittivity associ...
Article
GYROTRON V is the latest in a series of tunable, millimetre/submillimetre wavelength sources designed and built at the University of Sydney. The output of this source is converted into a focused, linearly-polarised beam using a variety of quasi-optical techniques, namely, a quasi-optical antenna and a Gaussian telescope.

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Projects (3)
Archived project
This thesis proposes a new approach in the design of Environmental Sensor Networks (ESN) by achieving the highest possible robustness with minimal redundancy. The proposed methodology produces the optimal number of sensor nodes require to best achieve its purpose, determines the optimal placement of sensor nodes, and investigates the impact caused by noise or gaps in the data. Noise and sensor data gaps are usually resulting from sensor errors (e.g., biofouling, electronics noise) or communication failures. The distribution of sensor nodes in a given region is proposed using Evolutionary Algorithm (EA) as the optimisation tool. The main advantage of EA is the fact that it can test a large number of possible solutions without bias from local optima. The algorithm compares the best possible configuration of sensor nodes in an ESN using fitness function as the difference between the result yielded from the network and the historical data as a validated environmental models. The results obtained were promising, however, the proposed methodology relies on historical data. To overcome this limitation a set of mobile platforms (e.g., drones, animal-carrying sensors, robots, boats of opportunity) is simulated as collecting data from the environment (i.e., from a large modelling output set). The results of the mobile platform readings are then spatial-temporally interpolated and the results used by the EA to propose a configuration of the first ESN. Validation for the proposed methods in this thesis is achieved by formulating and running the methods in a form of simulation study. The effectiveness of each ESN design produced in representing the RoI is compared against SouthEsk data model (i.e., as a representation for the actual measured value in the RoI). The performance of the proposed methods is also compared with some other methods in ESN design, including with expert knowledge. The main contributions of this work are the measure of ESN representativeness which enable to assess and to compare the performance of different ESN designs; the method to find optimum ESN design which best represents a region of interest with a balance between minimum redundancy and maximum robustness; and the use of mobile platforms for data sampling to capture environmental behaviour in a region of interest which is useful for ESN design in the absence of historical data.
Project