Tim was formerly the Associate Dean of Teaching and Learning in the Faculty of Engineering at the University of Technology. In the past he has also been the Director of Undergraduate Programs and the Program Head for the Telecommunications Engineering Program in the Faculty. Prior to joining the Faculty he worked for more than 10 years in the telecommunications industry.
His research interests have been in the area of antennas and propagation with a particular interest in multi-antenna systems, particularly multiple-input multiple output (MIMO) systems. He has published a number of papers and has supervised students undertaking research degrees in this area. He has also acted as a reviewer for conferences and journals.
He is also interested in teaching and learning and has been involved in the development and delivery of a number of innovative subjects and programs. Currently he is employed part-time on a number of teaching and learning related projects.
Various research projects and consultancies:
Since joining UTS Tim has worked on a number of funded research projects and consultancies. These include work with AWA, Canon, Ericsson and Motorola. Some of projects he has undertaken with these companies are:
- Design of super high frequency amplifiers on soft-substrates
- Analysis of mobile antenna performance in the presence of the human body
- Analysis and design of small diversity antennas for wireless office systems
- Indoor propagation modelling and measurement
He has also consulted in the area of electro-magnetic interference.
Olympic Broadcasting Organisations:
He has had an ongoing consultancy role with Olympic Broadcasting Organisations and he worked at the Sydney (2000), Athens (2004), Torino (2006), Beijing (2008), Vancouver (2010), London (2012) and Sochi (2012) Olympic Games and will be involved in broadcasting at the Rio Games in 2016.
Smith, DB & Aubrey, TA 2005, 'Differential unitary space-time superset modulation', European Transactions On Telecommunications, vol. 16, no. 4, pp. 303-307.View/Download from: UTS OPUS or Publisher's site
A simple framework is presented for transmission of constellation supersets, starting from a consideration of differential diagonal unitary space-time modulation (DUSTM), called DUST superset modulation (DUSTSM). The need for extension of previously stat
Smith, DB & Aubrey, TA 2005, 'Differential Unity space-time Superset Modulation', European Transactions On Telecommunications, vol. 16, no. 4, pp. 303-307.View/Download from: UTS OPUS or Publisher's site
A simple framework is presented for transmission of constellation supersets, starting from a consideration of differential diagonal unitary space-time modulation (DUSTM), called DUST superset modulation (DUSTSM). The need for extension of previously stated design criteria for DUSTM is demonstrated by DUSTSM achieving full spectral efficiency with good bit error rate (BER) performance in a Rayleigh flat fading channel despite an effective multicylic group construction. Two cases for two different data rates and number of transmit antennas are illustrated in which the performance of DUSTSM exceeds that of DUSTM.
Smith, DB & Aubrey, TA 2003, 'Performance degradation of differential space-time modulation in fast frequency flat fading Rayleigh MIMO channels', Electronics Letters, vol. 39, no. 17, pp. 1278-1280.View/Download from: UTS OPUS or Publisher's site
In this paper, techniques are presented to extend FDTD, PML and Murs second order ABC to the non-uniform mesh case for scattering problems from a consideration of improving the efficiency of computer codes to run on parallel computers. An alternative met
In this paper, techniques are presented to extend FDTD, PML and Mur's second order ABC to the non-uniform mesh case for scattering problems from a consideration of improving the efficiency of computer codes to run on parallel computers. An alternative method to obtain the space derivatives in non-uniform mesh FDTD and non-uniform mesh PML ABC is presented which provides a second order accuracy. Mur's second order ABC has also been extended to the non-uniform mesh case with a First order accuracy which is an improvement over an existing method. A method of extending the pure scattered-field formulation to the PML medium is described. The electric fields inside a single layer dielectric sphere as well as a three layer dielectric sphere illuminated by a sinusoidal uniform plane wave have been computed which compare well with the results from an exact formulation. © 1996 Taylor & Francis.
Liu, Z, Sanagavarapu, AM, Aubrey, TA & Belcher, R 1995, 'Techniques For Implementation Of The FDTD Method On A Cm-5 Parallel Computer', IEEE Antennas And Propagation Magazine, vol. 37, no. 5, pp. 64-71.
Aubrey, T & White, P 1992, 'Simple numerical integration of logarithmic singularities in moment method solutions of electromagnetic problems', Electronics Letters, vol. 28, no. 16, pp. 1519-1521.View/Download from: Publisher's site
Moment method solutions to electromagnetic problems can require the integration of functions containing logarithmic singularities. A simple technique for the numerical integration of these singularities is presented. The technique is applied in the calculation of the self-impedance of a surface dipole. The convergence of the solution using this method is compared to the convergence of existing methods. © 1992, The Institution of Electrical Engineers. All rights reserved.
Ang, KCS & Aubrey, T 2014, 'Transforming multiple stakeholder insights into education action: developing a pragmatic EIT professional advisory framework', Proceedings of the Australasian Association of Engineering Education (AAEE) Conference 2014, AAEE - Annual Conference of Australasian Association for Engineering Education, AAEE 2014, Wellington.View/Download from: UTS OPUS
This paper discusses the formation of a stakeholder engagement framework for a Professional Advisory board (PAb). These collaborative undertakings were initially conducted to review post-graduate programs in the Faculty of Engineering and Information Technology (FEIT) at the University of Technology Sydney (UTS). This led to the realisation of a pragmatic and collaborative engagement process that benefits industry and the education sector whilst developing students that are able to deal with current and emergent challenges.
PURPOSE OR GOAL
The PAb is a network of academics, students, alumni and industry members that undertakes to engage, advice and review discipline-specific faculty programs from multiple perspectives to ensure that programs remain relevant and valuable to industry. As the faculty moves towards reengineering their approach to teaching and learning as part of a university-wide initiative known as 'Learning 2014' (L2014), this provides the opportunity to shape a more engaged and collaborative teaching and learning culture within its programs.
The collaborative stakeholder process was built upon an intensive series of mixed methods and action research initiatives as engagement mechanisms. These pragmatic and emergent mechanisms involved quantitative surveys, focus groups, in-depth interviews, industry workshops and multiple rounds of academic consultations.
The PAb framework was piloted in June 2014. Initial results from a feedback survey are also reported. The collaborative framework, whilst promising, engaging and conceptually robust, has not yet reached a stable state. The framework will be extended to other EIT disciplines in order to evaluate its outcomes across various disciplinary contexts and to optimise the framework's efficacy for future iterations. This paper suggests a pragmatic and robust framework to integrate industry and stakeholder expectations with faculty program deliverables in a way that is valu...
Ang, K & Aubrey, TA 2013, 'Shelf-life of post-graduate engineering education: relevance and currency in an age of dynamic industry expectations', 24th Annual Conference of the Australasian Association for Engineering Education (AAEE2013), Australasian Association of Engineering Education (AAEE) Conference 2013, Australasian Association of Engineering Education (AAEE), Sunshine Coast.View/Download from: UTS OPUS
BACKGROUND In response to the changing environment, industry requirements and the underpinning AQF specifications for higher education awards, UTS Faculty of Engineering and Information Technology (FEIT) has embarked on a research project to review their Masters programs to ensure that the commitment to practice-based fields in both Engineering and Information Technology (EIT) education remains relevant. Both fields share synergies for teaching and research, and both professions are constantly evolving in a dynamic environment. For context, postgraduate courses in this study are the Masters of Enginering (ME), Engineering Studies (MES), Engineering Management (MEM), Internetworking (MSc.I) and Information Technology (MIT). This paper draws on research insights that form part of a larger project that entails stakeholder consultations (students/graduates, industry and academics) as part of the 3 yearly Faculty Masters review and renewal process. The research completed to date includes quantitative and qualitative perspectives of current students and recent graduates regarding their learning and professional expectations and actual experiences, including relevance and currency in industry. PURPOSE The key purpose of this paper is to present the insights based on research conducted with stakeholder perspectives centred on their needs, expectations and actual experience. Consequently the purpose is to evaluate the currency, relevance and value of current postgraduate program contributions to industry and the Engineering and IT profession; and more importantly in addressing future industry needs to ensure that Engineering and IT education programs remains robust, relevant and sustainable in dynamic industry environments where rapid change is the norm. DESIGN/METHOD The study utilised a mixed-methodology with quantitative and qualitative perspectives. 308 students and graduates were surveyed online to gauge their attitudes with regards to the relevance and contributi...
Godfrey, E, Aubrey, TA & King, R 2010, 'Who leaves and who stays? Retention and attrition in Engineering Education', Engineering Education 2010 (EE2010): Inspiring the next generation of engineers, Engineering Education Conference, The Higher Education Academy Engineering Subject Centre, Aston University, UK, pp. 1-13.View/Download from: UTS OPUS
At a time of high demand for engineering graduates, the mean graduation completion rate of engineering undergraduates in Australia has been identified as approximately 54% (with considerable variation across institutions and sectors). This proportion of non- completions has been viewed as an excessive loss to the qualified workforce of Australia. Broad brush, governmentcollected statistics do not, however, provide the level of detail required to understand who leaves, when and why they leave, and where they go. This paper reports on a pilot study undertaken to precede and inform final decisions on research design and methodology for a multi institutional project seeking to understand and reduce student attrition from engineering degrees across Australia. The aim of the project is to produce guidelines on curriculum formulation and delivery strategies to reduce attrition in engineering programs while meeting outcomes. The pilot study was conducted at an institution which has a relatively diverse range of students, a high proportion of whom study part time, and engineering degree structures incorporating traditional and internship-based degrees. Results from a cohort analysis, tracking pathways to completion or noncompletion of the degree for the cohorts from two specific entry years will be presented. From this analysis, groups of students who 'persisted over long periods', 'switched to another degree' or 'withdrew from the university' were identified and interviewed. Their experiences and stories, were an essential ingredient for a better understanding of the dynamics of retention/attrition and actors which required further questioning before proceeding with the multi institutional study.
Godfrey, E, Aubrey, T, Crosthwaite, C & King, R 2010, 'Who leaves and when do they go? Retention and attrition in engineering education', Proceedings - Frontiers in Education Conference, FIE.View/Download from: Publisher's site
At a time of high demand for engineering graduates, the mean graduation completion rate of engineering undergraduates in Australia has been identified as approximately 54% (with considerable variation across institutions and sectors). This paper reports on the initial results of cohort analyses undertaken at two engineering degree granting institutions as part of a multi institutional project seeking to understand and reduce student attrition from engineering degrees across Australia. Both institutions have a predominantly urban student population and location, but whilst one offers a conventional four year degree the other integrates two semesters of internship into its degree structure. A cohort analysis procedure, tracking pathways to completion or non-completion of the degree, applicable across diverse institutions, was piloted. Attributes such as gender, academic background, full or part time study, engineering major and student maturity were identified for each member of the cohort. The patterns revealed by these fine grained cohort analyses challenged some anecdotal perceptions and provided evidence of the inadequate nature of generalizations around attrition statistics, and the need for institutional context and culture to be considered. © 2010 Crown.
Godfrey, E, Aubrey, T & King, R 2010, 'Work in progress - Academic Pathways of People Learning Engineering - An Australian Study', Proceedings - Frontiers in Education Conference, FIE.View/Download from: Publisher's site
In Australia a multi-institutional project is underway, with one of its major themes the understanding and reduction of attrition in engineering programs. The Academic Pathways for People Learning Engineering Survey (APPLES) instrument was trialled at a participating institution as a possible precursor to its application in the eight collaborating institutions. APPLES had been validated and delivered to over 4000 engineering undergraduates by the Academic Pathways Study in the US. The survey was trialled with 259 engineering students from different year levels to explore its potential to find links between students' perceptions of their motivation, skills and confidence with their goals to continue to degree completion and employment in engineering. This paper reports on the initial findings from the Australian pilot study. Matching the self reported data in the survey with statistical data has, even at this initial stage, highlighted some discrepancies and topics for further investigation. © 2010 IEEE.
Lu, Z, Kadi, A & Aubrey, TA 2009, 'A hybrid CME-LS channel estimation approach for broadband MIMO-OFDM systems', Symposium on Communications and Information Technology, 2009. ISCIT 2009. 9th International, International Symposium on Communications and Information Technologies, IEEE, Incheon, Korea, pp. 313-318.View/Download from: UTS OPUS or Publisher's site
A channel estimation approach yielding both channel gains and the number of multi-paths is presented. The algorithm is based on a variation of conditional model order estimation (CME), and is proposed for MIMO-OFDM systems. The CME based estimator is shown to be viable in both fixed and mobile broadband MIMO-OFDM wireless applications, and takes advantage of determining the nonzero taps as well. The performance of the approach is compared to the popular minimum description length (MDL) algorithm for estimation of the number of channel paths, by means of simulation in the context of a 2times2 MIMO-OFDM transceiver system. Results indicate that the new algorithm is superior in channel order estimation to the MDL algorithm in MMO-OFDM system over a noisy frequency selective fading channel.
Lu, Z, Kadi, A & Aubrey, TA 2009, 'A CME Based Channel Estimation Approach for MIMO-OFDM Systems', Proceedings of the 5th International Conference on Wireless communications, networking and mobile computing, International Conference on Wireless Communications, Networking and Mobile Computing, IEEE Press, Beijing, China, pp. 783-786.View/Download from: UTS OPUS or Publisher's site
A pilot-assisted, conditional model-order estimation (CME) based channel estimation algorithm is presented. The algorithm is proposed for MIMO-OFDM systems and can detect both channel frequency responses and number of multi-path taps. In addition, the modified CME estimator is also verified its capacity in determining the nonzero taps. The performance of the proposed approach is compared to the popular minimum description length (MDL) algorithm for estimation of the number of channel paths, by means of simulation in the context of a 2x2 MIMO-OFDM transceiver system. Result indicates that the new algorithm is superior in channel order estimation to the MDL algorithm in MMO-OFDM system over a noisy frequency selective fading channel.
Smart, K & Aubrey, TA 2009, 'Evaluation of a magnetic near field scanner', Microwave Conference, 2009. APMC 2009. Asia Pacific, Asia-Pacific Microwave Conference, IEEE, Singapore, pp. 413-416.View/Download from: UTS OPUS or Publisher's site
Traditionally, the measurement of antenna performance often required significant capital outlay on anechoic test chambers and associated test equipment. A novel device manufactured by Canadian company Emscan that can perform some of these measurements in a bench-top environment may offer a solution. A study was undertaken into the performance of the Emscan near-field scanner. Comparisons with measurements taken in anechoic chamber and theoretical models using CST microwave studio are used in the evaluation of the scanner as well as measurements of repeatability and accuracy.
Lawrence, EM, Loke, L, Raban, R, Brookes, WC & Aubrey, TA 2009, 'Towards an Understanding of Collaboration in Teaching Technology Subjects in an Amalgamated Faculty of Engineering and Information Technology', International Conference on Mobile, Hybrid, and On-line Learning EL & ML 2009, International Conference on Mobile, Hybrid, and On-Line Learning, IEEE Computer Society Conference Publications, Cancun, Mexico, pp. 47-52.View/Download from: UTS OPUS or Publisher's site
The paper sets out a collaborative approach for teaching technology subjects. It Illustrates the benefits of this approach over the single academic owning a particular subject. The paper presents preliminary findings from interviews with academics in a newly combined Faculty of Engineering and Information Technology. It concludes by pointing the way to the future of htis funded research project.
Aubrey, TA & Aboura, K 2008, 'Bandwidth Utilisation for volume-to-volume UWB MIMO Communications', Proceedings of 3rd International Symposium on Wireless Pervasive Computing (ISWPC 2008), International Symposium on Wireless Pervasive Computing, IEEE, Santorini, Greece, pp. 88-92.View/Download from: UTS OPUS or Publisher's site
Previous studies have investigated communications between regions of space and have considered the effect of antenna volume in determining the theoretical capacity of multiple-input multiple-output (MIMO) communications systems. In this paper the effects of antenna 1volume on available bandwidth for MIMO systems is considered. It is demonstrated that while higher order modal connections can be established even for small antennas that a fundamental limitation on bandwidth exists. This limitation becomes important for ultra-wide band (UWB) communications systems.
Smith, DB, Abhayapala, TD & Aubrey, TA 2004, 'A generalised (M,NR) MIMO Rayleigh channel model for non-isotropic scatterer distributions.', Proceedings of Workshop on the Application of Radio Science, (WARS) 2004, Workshop on the Application of Radio Science, National Committee for Radio Science, Hobart, Australia, pp. 1-6.View/Download from: UTS OPUS
Smith, DB & Aubrey, TA 2003, 'Generalised space-time modelling of the MIMO channel applied to analysing and optimising transmit antenna configurations', Proceedings of IEEE International Conference on Communications, IEEE International Conference on Communications, IEEE, Alaska, USA, pp. 1978-1982.View/Download from: UTS OPUS or Publisher's site
For the purposes of macroscopic system design a space-time Rayleigh fading multiple-input multiple-output (MIMO) radio channel is modelled for an arbitrary transmit antenna configuration of three to six transmit antennas. A traditional ring of scatterers model is use to generate the space-time cross correlations and thence flat fading channel distortions. A general trend is demonstrated for a specific non-coherent modulation scheme where the optimality of different transmission frame lengths can be related to the well known autocorrelation functions; based on this trend two frame lengths are chosen for MIMO channel analysis. Several beneficial arbitrary transmit antenna configurations are obtained from this analysis using some typical arbitrary configurations, and some initial optimisation using a genetic algorithm, from which further possible optimisation is proposed.
Wang, JG, Mohan, AS & Aubrey, TA 1996, 'Angles-of-arrival of multipath signals in indoor environments', 1996 IEEE 46TH VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3, IEEE 46th Vehicular Technology Conference - Mobile Technology for the Human Race (VTC 96), I E E E, ATLANTA, GA, pp. 155-159.
Aubrey, T & White, P 1993, 'Comparison of switched pattern diversity antennas', IEEE Vehicular Technology Conference, pp. 89-92.
Switched pattern diversity reception is implemented by using antenna elements with different directional radiation patterns and switching the receiver to the element providing the best output. The use of pattern diversity can improve system performance. We simulate the performance of various ideal pattern diversity antennas. The results are compared with an ideal omni-directional antenna and with energy density antennas. Significant improvements are shown for diversity antennas in multi-path environments characterized by Rayleigh and Rician amplitude distributions.