Martin Hayes

University of Limerick, Dept of Electronic & Computer Engineering, Faculty Member

Followers

Following

Public Views

Interests

Uploads

Papers by Martin Hayes

Human-in-Loop: A Review of Smart Manufacturing Deployments

Systems, Jan 6, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more

Download

TensorFlow Enabled Deep Learning Model Optimization for enhanced Realtime Person Detection using Raspberry Pi operating at the Edge

In this paper Quantization effects are assessed for a real time Edge based person detection use c... more In this paper Quantization effects are assessed for a real time Edge based person detection use case that is based on the use of a Raspberry Pi. TensorFlow architectures are presented that enable the use of real-time person detection on the Raspberry Pi. The model quantization is performed, performance of quantized models is analyzed, and worstcase performance is established for a number of deep learning object detection models that are capable of being deployed on the Pi for realtime applications. The study shows that the inference time for a suitably optimized TensorFlow enabled solution architecture is significantly lower than for an unquantized model with only slight cost implications in terms of accuracy when benchmarked against a desktop implementation. An industrial standard floor limit value of greater than 70% is achieved on the quantized models considered with a reduced detection time of less than 3ms. The Deep Neural Network model is trained using the INRIA Person Detecti...

Download

State-space µ analysis for an experimental drive-by-wire vehicle

International Journal of Robust and Nonlinear Control, 2008

This paper considers the application of the skewed structured singular value to the robust stabil... more This paper considers the application of the skewed structured singular value to the robust stability of systems subject to strictly real parametric uncertainty. Three statespace formulations that counteract the discontinuous nature of this problem are detailed. It is shown that the calculation of the supremum of the structured singular value over a frequency range using these formulations transforms into a single skewed structured singular value calculation. Like the structured singular value, the calculation of the exact value of the skewed structured singular value is a NP-hard problem, therefore alternative, less computationally demanding algorithms to determine upper and lower bounds are necessary. Two algorithms that determine upper and lower bounds on the skewed structured single value are presented. These algorithms are critically assessed by performing a robust stability analysis on a safety-critical experimental drive-by-wire vehicle.

Download

Quantitative feedback design for a benchmark quadruple-tank process

IET Irish Signals and Systems Conference (ISSC 2006)

In this paper level control for a quadruple-tank process with variable nonlinear zero dynamics is... more In this paper level control for a quadruple-tank process with variable nonlinear zero dynamics is considered. This provides a nice benchmark problem that illustrates some of the challenges posed by complex interconnected systems for linear design paradigms. A Quantitative Feedback Theory (QFT) methodology is used to provide robust control of the water level in the lower two tanks. The linear design is validated on the nonlinear system model.

Download

On the computation of the maximal structured singular value for aeronautical applications

Proceedings. IEEE International Symposium on Computer Aided Control System Design

This paper considers the necessary transformations and the computational issues associated with t... more This paper considers the necessary transformations and the computational issues associated with the determination of the maximal structured singular value, μ max , without the use of a frequency gridding strategy. It is shown that, for the case of purely real model perturbations, convergence difficulties exist in determining bounds on μ max using existing Matlab software. A new computational scheme is presented which improves on existing methods for the computation of the worst case combination of real uncertain parameters. This scheme easily outperforms regularisation type solutions, which have been suggested as one way of improving the convergence properties of a strictly real robustness analysis. The improvement is illustrated on a well known civil aircraft robustness analysis example.

Download

A Covid-19 viral transmission prevention system for embedded devices utilising deep learning

2021 32nd Irish Signals and Systems Conference (ISSC), 2021

The coronavirus pandemic (COVID-19) has created an urgent need for different monitoring systems t... more The coronavirus pandemic (COVID-19) has created an urgent need for different monitoring systems to prevent viral transmission because of its severity and contagious aspect. This paper proposes design and implementation of a hardware-software solution that uses supervised machine learning algorithms to examine an individual and determine if he/she poses a viral transmission danger. The solution proposed was developed utilising an ARM embedded device along with different sensors to detect and monitor COVID-19 symptoms and, at the same time, to enforce wearing of a mask by using deep learning computer vision.

Download

Title On localization with robust power control for safety critical wireless sensor networks On localisation with robust power control for safety critical wireless sensor networks

Download

Throughput rate control for an 802.15.4 wireless body area network using static and low order anti-windup techniques

2007 Mediterranean Conference on Control & Automation, 2007

In this paper, low-order and static anti-windup control laws are used to enhance the performance ... more In this paper, low-order and static anti-windup control laws are used to enhance the performance of an 802.15.4 wireless sensor network. 'Real world' conditions are explicitly considered in the modelling phase using Kotz's axioms. Anti-Windup techniques are shown to improve system performance in the face of naturally occurring input controller saturation. Joint Quality of Service and optimal network power loss is demonstrated through simulation and verified practically using a mote based network.

Download

On μ-analysis and synthesis for systems subject to real uncertainty

2003 European Control Conference (ECC), Sep 1, 2003

The paper introduces a new approach for the computation of a lower bound on the structured singul... more The paper introduces a new approach for the computation of a lower bound on the structured singular value (SSV), µ in the presence of purely real and mixed/complex uncertainties. The approach utilises a frequency sweeping technique based on a linear fractional transformation representation of structured uncertainty. The technique is applied to a well-known civil transport aircraft example. A fixed structure controller synthesis strategy is developed, which addresses potential stability problems that can occur using standard design methodologies. Notation µ(M) structured singular value (SSV) of M σ(M) largest singular value of M F l (M, ∆) lower Linear Fractional Transformation of M, ∆ real part of a complex number imaginary part of a complex number R field of real numbers C field of complex numbers λ(M) eigenvalues of M

Download

Development and validation of a low-cost mobile robotics testbed

Open Engineering, 2012

This paper considers the design, construction and validation of a low-cost experimental robotic t... more This paper considers the design, construction and validation of a low-cost experimental robotic testbed, which allows for the localisation and tracking of multiple robotic agents in real time. The testbed system is suitable for research and education in a range of different mobile robotic applications, for validating theoretical as well as practical research work in the field of digital control, mobile robotics, graphical programming and video tracking systems. It provides a reconfigurable floor space for mobile robotic agents to operate within, while tracking the position of multiple agents in real-time using the overhead vision system. The overall system provides a highly cost-effective solution to the topical problem of providing students with practical robotics experience within severe budget constraints. Several problems encountered in the design and development of the mobile robotic testbed and associated tracking system, such as radial lens distortion and the selection of rob...

Download

Addressing Non-linear Hardware Limitations and Extending Network Coverage Area for Power Aware Wireless Sensor Networks

Wireless Sensor Networks, 2011

Download

Computation and applications of the structured singular value

IV 8 Non-Linear Systems 44 8 1 Linearisation 2 9 Sum m ary 3 N ew Algorithm 3 1 D ual Problem 3 1... more IV 8 Non-Linear Systems 44 8 1 Linearisation 2 9 Sum m ary 3 N ew Algorithm 3 1 D ual Problem 3 1 1 A pplication of Geometric H ahn-Banach Theorem 3 2 O utline of the A lgorithm 3 2 1 O uter Loop 50 3 2 2 Inner Loop 3 3 Inner Loop Analysis and Some Suggested Improvements 53 3 3 1 The Linear Program (LP) 53 2 5 1 Statem ent of the Problem 36 3 3 2 CVD 56 vi 3 4 Improvements to the Basic Algorithm 60 3 4 1 Initialisation 60 3 4 2 M atrix Pencils 61 3 4 Tight C onstraints 64 3 5 Improvements with Real U ncertainty 68 3 6 Im plem entation of Changes to the Basic Algorithm 70 3 7 Proof of Convergence 3 8 Sum m ary 4 Algorithm Performance 77 4 1 R eliability of the Basic Algorithm 4 1 1 Complex U ncertainty 4 1 2 R eal/M ixed U ncertainty 4 1 3 Effect of Problem Size on Com puting Times 4 2 Improvements to the Basic Algorithm 4 2 1 Reliability 4 2 2 Accuracy 4 2 3 M ixed/Real U ncertainty 4 3 1-Norm Vs 2-Norm M ethods 92 4 3 1 T he Proxim ity Problem 92 4 3 2 Relaxing Accuracy Requirements 101

Download

Worst Case Analysis of a Simple Mimo Mass-Spring-Damper System

IFAC Proceedings Volumes, 2005

Min-Max Model Predictive Power Control Strategy for CDMA Cellular Networks

Proceedings of the 18th IFAC World Congress, 2011

This paper applies an open-loop min-max MPC strategy to the uplink radio power control problem fo... more This paper applies an open-loop min-max MPC strategy to the uplink radio power control problem for a CDMA cellular network assessed over time-varying channels. The new power control algorithm is shown to robustly compensate for channel fading uncertainty as well as to reduce the effect of interference. This is achieved by implementing a computationally efficient min-max MPC mechanism based on a simple model of the tracking error that is estimated at each sampling time from the local SINR. The numerical efficiency of the resulting design is benchmarked against a number of existing strategies via a representative selection of simulation scenarios.

Download

On localization with robust power control for safety critical wireless sensor networks

Journal of Control Theory and Applications, 2011

A hybrid methodology is proposed for use in low power, safety critical wireless sensor network ap... more A hybrid methodology is proposed for use in low power, safety critical wireless sensor network applications, where quality of service orientated transceiver output power control is required to operate in parallel with radio frequency based localisation. The practical implementation is framed in an experimental procedure designed to track a moving agent in a realistic indoor environment. An adaptive time synchronised approach is employed to ensure the positioning technique can operate effectively in the presence of dataloss and where the transmitter output power of the mobile agent is varying due to power control. A deterministic multilateration based positioning approach is adopted and accuracy is improved by filtering signal strength measurements overtime to account for multipath fading. The location estimate is arrived at by employing least square estimation. Power control is implemented at two separate levels in the network topology. Firstly power control is applied to the uplink between the tracking reference nodes and the centralized access point. A number of algorithms are implemented highlighting the advantage associated with using additional feedback bandwidth, where available, and also the need for effective time delay compensation. The second layer of power control is implemented on the uplink between the mobile agent and the access point and here quantifiable improvements in quality of service and energy efficiency are observed. The hybrid paradigm is extensively tested experimentally on a fully compliant 802.15.4 testbed, where mobility is considered in the problem formulation using a team of fully autonomous robots.

Download

On the effect of communication constraints on robust performance for a practical 802.15.4 wireless sensor network benchmark problem

2008 47th IEEE Conference on Decision and Control, 2008

This work considers the effect of communication constraints on the dynamic performance of wireles... more This work considers the effect of communication constraints on the dynamic performance of wireless sensor networks that operate in a power aware mode. In particular, the hardware output power limit and quantization constraints that arise practically when only a limited number of power levels are available to the designer are considered in this regard. A novel approach is presented that uses an intuitively appealing graphical means of representing an output power constraint, whereby the saturation block that naturally occurs in a practical setting is mapped from the output of the plant and is compensated through the use of a robust Anti-Windup scheme. System performance and stability is verified using quantitative feedback theory in the linear part of the design. The hybrid controller that ensues is extensively tested experimentally, on a fully compliant 802.15.4 testbed, where mobility is considered in the problem formulation using a team of fully autonomous robots. A benchmark comparison is made between this approach and a number of existing strategies suggesting that an antiwindup approach is an entirely appropriate methodology for the problem at hand.

Download

An Antiwindup Approach to Power Controller Switching in an Ambient Healthcare Network

International Journal of Ambient Computing and Intelligence, 2011

This paper proposes a methodology for improved power controller switching in mobile Body Area Net... more This paper proposes a methodology for improved power controller switching in mobile Body Area Networks operating within the ambient healthcare environment. The work extends Anti-windup and Bumpless transfer results to provide a solution to the ambulatory networking problem that ensures sufficient biometric data can always be regenerated at the base station. The solution thereby guarantees satisfactory quality of service for healthcare providers. Compensation is provided for the nonlinear hardware constraints that are a typical feature of the type of network under consideration and graceful performance degradation in the face of hardware output power saturation is demonstrated, thus conserving network energy in an optimal fashion.

Download

Robust power control for IEEE 802.15.4 wireless sensor networks with round-trip time-delay uncertainty

Wireless Communications and Mobile Computing, 2009

This paper presents a novel, practically implementable robust Power Control (PC) technique that i... more This paper presents a novel, practically implementable robust Power Control (PC) technique that is generally applicable to a variety of IEEE 802.15.4 infrastructure and peer-to-peer wireless sensor networks (WSNs) where there is a round-trip time-delay uncertainty. In this methodology, robust stability and performance constraints are cast as a set of exclusion regions on the Nichols chart. The desired PC strategy is achieved through an iterative shaping of the system frequency response until these constraints are satisfied. A Smith Predictor (SP) is also adopted to mitigate the effects of time delay that occurs quite naturally in this type of problem. Such an approach is shown to be entirely appropriate for the discrete time controller design problem at hand. The designs are validated experimentally using a fully compliant 802.15.4 testbed where mobility is introduced using autonomous robots. This testbed provides a good basis for a formal comparison of the new approach against a number of existing strategies.

Download

Practical assessment of hardware limitations on power aware wireless sensor networks—An anti‐windup approach

International Journal of Robust and Nonlinear Control, 2010

This work considers the effect of hardware constraints that typically arise in practical ‘power‐a... more This work considers the effect of hardware constraints that typically arise in practical ‘power‐aware’ wireless sensor network systems. A rigorous methodology is presented that quantifies the effect of output power limit and quantization constraints on bit error rate performance. The approach uses a novel, intuitively appealing means of addressing the output power constraint, wherein the attendant saturation block is mapped from the output of the plant to its input and compensation is then achieved using a robust anti‐windup scheme. A priori levels of system performance are attained using a quantitative feedback theory approach on the initial, linear stage of the design paradigm. This hybrid design is assessed experimentally using a fully compliant 802.15.4 testbed where mobility is introduced through the use of autonomous robots. A benchmark comparison between the new approach and a number of existing strategies is also presented. Copyright © 2009 John Wiley & Sons, Ltd.

Download

Ambulatory wireless sensor network power management using constrained explicit generalised predictive control

International Journal of Control, 2011

This work considers the problem of controlling transmit power within a wireless sensor network (W... more This work considers the problem of controlling transmit power within a wireless sensor network (WSN), where the practical constraints typically posed by an ambulatory healthcare setting are explicitly taken into account, as a constrained received signal strength indicator (RSSI) tracking control problem. The problem is formulated using an explicit generalised predictive control (GPC) strategy for dynamic transmission power control that ensures a balance between energy consumption and quality of service (QoS) through the creation of ...

Martin Hayes

Uploads

Papers by Martin Hayes

Log In