Department of Electrical and Computer Engineering
Postgraduate research projects
Research is an integral part of postgraduate study. Postgraduates work side-by-side with staff and explore new ideas together. To follow is just a selection of projects our postgraduate students are currently involved in.
- » A design and simulation environment for IEC61499 function blocks
- » Base station placement in multi-floored buildings
- » Automated and visual approach for inconsistency checking of requirements
- » Modelling radio wave propogation in buildings: Solving 19th Century physics with 21st Century computers
- » Designing a high level test specification language for IEC 61499 function block diagram
- » Development of a screw removal robot
The objective of this research is to establish a design and simulation environment for IEC61499 Function Blocks, based on the software framework proposed by the Industrial Informatics research group. The automation industry is now demanding for high flexibility and reconfigurability in the control system design. They are looking for a way to change and re-design the system configuration more easily, in order to produce different customized products. The traditional centralised control approach with Programmable Logic Controller (PLC) is not able to cope with this urge. To address this issue, International Electrotechnical Commission (IEC) has established a new standard called IEC61499. This aims to enhance interoperability and software reusability. It introduces a new modelling concept called “Function Blocks,” which can be used to create a decentralised and distributed configuration in order to achieve the demanded flexibility and reconfigurability. However this new distributed design faces two challenges. One is the complexity in the system design. It becomes difficult to ensure the correctness and robustness of the controller design. The other one is the difficulty in obtaining the industrial acceptance at this stage as new design structure will introduce extra costs.
To address these two challenges, an integrated software environment is essential for system engineers to design distributed systems more easily. My research contributes in the modelling and simulation part of this framework by introducing an integrated software environment that links Function Block tools with existing industrially acceptable tools such as MATLAB Simulink. This is achieved by direct socket communication as well as a complete model transformation. This will potentially improve the industrial acceptance to this new standard. With this environment, a systematic way of modelling and designing a control system can be formalized, and simplification of system modelling and design process can be achieved. A motor model is used to test and demonstrate this simulation environment with the model transformation tools developed in this research.
The Base Station Placement (BSP) problem for multi-floored buildings is analysed. The optimal base station locations are identified from potential base station sites (including outdoor sites) for stationary users under dynamic conditions, in which calls arrive and depart over a period of time. The School of Engineering Tower (at The University of Auckland) is analysed with users on two different floors. The analysis considers both forward and reverse link Signal-to-Interference Ratios (SIRs). Two cases, each having five different traffic scenarios (with varying frequency of calls) are presented. The first case considers only internal base station sites and second case considers both internal and external sites. The results indicate that for both cases, internal vertically aligned base station sites are optimal to serve the users with a minimum call failure rate. The propagation conditions of the analysed Tower are typical of many high-rise buildings. It is therefore expected that the results and trends observed here can be extended to other buildings of similar construction.
Requirements are commonly vague and ambiguous. In this paper, we describe an automated Inconsistency Checker called MaramaAI for checking for high- level inconsistency between textual requirements, abstract interactions and Essential Use Cases. We use concepts of phrase extraction and essential interaction patterns to carry out these checks. We provide further support for checking of requirements quality attributes such as completeness and correctness using visual differencing.
Modelling radio wave propogation in buildings: Solving 19th Century physics with 21st Century computers
Radio-wave propagation is governed by Maxwell's equations (formulated by James Clerk Maxwell in 1861). These equations describe in abstract form the relationships between electric and magnetic fields and "represent the most outstanding achievement of 19th-century science" (as stated by Nobel Laureate Richard Feynman). However, analytical solutions to Maxwell's equations are difficult, if not impossible, to obtain for anything other than simple cases, due to boundary condition complexity. Solutions to this dilemma lie in the field of Computational Electromagnetics, which combines electrical engineering, computer science and physics, to provide numerical solutions to Maxwell's equations.
This research focuses on applying computational electromagnetic techniques to the problem of radio wave propagation within buildings, with the aim of improving the performance and reliability of current and emerging wireless systems. Until very recently, applications of computational electromagnetic techniques, such as the Finite-Difference Time-Domain (FDTD) method, to this problem have largely focused on 2D representations of buildings due to high computational requirements. However, the work of the author and access to parallel and cluster computing resources, such as BeSTGRID, have allowed us to investigate propagation within buildings using the 3D FDTD method. This poster presents some of the author's novel work related to visualising the flow of energy by projecting streamlines through the Poynting vector field.
Designing a high level test specification language for IEC 61499 function block diagram
Mohamad Farid Jafar
Function block diagram is a diagram that describes function between input and output variables. It consists of events, variables, states, and algorithms. The block diagram is used to provide logic for a control system. The current method to verify the logic is by exercising it with a formula specification. Most of the formula Specification is written either in local temporal logic (LTL) or computational tree logic (CTL) syntax. The drawback for both of these syntaxes is that it requires depth knowledge in both syntaxes to write or translate it. If the syntax is wrongly stated or placed, a different result will be produced by model checker. Most of the time, an intervention from an expert is required to translate the verification specification into a proper formula syntax.
We propose a high-level test specification language that shifts text-based specification syntax into visual-based specification syntax. The idea is to use visual notation to write the formula specification and provide a mean of checking such as simulation to pre-validate the syntax. For the purpose of this study, we are following the IEC 61499 function block diagram standard. This standard is widely accepted and adapted by the major players in industries. We hope this newly proposed high-level visual test specification language can promote user participation in validation process without being set back by the unfamiliarity of formula specification.
Building interior renovation in Japan commonly requires construction workers to remove self-tapping screws from suspended ceiling beams by hand. This is a long and physically demanding process. It is, however, simple and repetitive, making it ideal for automation. A ceiling beam screw removal robot is proposed for the screw removal step. Rather than cutting or pulling the screws from the beam, which damages both the screws and the beam, the system takes a more sustainable solution, using a custom screw removal tool to unscrew the screw, leaving the materials in a reusable condition.
The robot used is a Mitsubishi PA10 7 degree-of-freedom industrial robot manipulator. Operating such large and powerful robot has a threat to safety, both to the human, and the surrounding environment. In this research we create a safe and novel simulation environment that is shown to save development cost and improve efficiency. Most importantly, we show that the simulation environment ensures safety for the robot developers during the development process, as well as for training end-users in operating the robot to remove screws.