Liam Kilmartin

• M Eng Sc (Electronic Engineering)
• Lecturer at Ollscoil na Gaillimhe – University of Galway

The muscarinic-cholinergic system is involved in the pathophysiology of bipolar disorder (BD), and contributes to attention and the top-down and bottom-up cognitive and affective mechanisms of emotional processing, functionally altered in BD. Emotion processing can be assessed by the ability to inhibit a response when the content of the image is em...

Neuroimaging evidence implicates structural network-level abnormalities in bipolar disorder (BD); however, there remain conflicting results in the current literature hampered by sample size limitations and clinical heterogeneity. Here, we set out to perform a multisite graph theory analysis to assess the extent of neuroanatomical dysconnectivity in...

This study investigates changes on white matter microstructure and neural networks after 6 months of switching to clozapine in schizophrenia patients compared to controls, and whether any changes are related to clinical variables. T1 and diffusion-weighted MRI images were acquired at baseline before commencing clozapine and after 6 months of treatm...

Background: Synchronous and antisynchronous activity between neural elements at rest reflects the physiological processes underlying complex cognitive ability. Regional and pairwise-connectivity investigations suggest perturbations in these activity patterns may relate to widespread cognitive impairments seen in bipolar disorder (BD). Here we take...

Background: Functional abnormalities, mostly involving functionally specialized subsystems have been associated with disorders of emotion regulation such as bipolar disorder (BD). Understanding how independent functional subsystems integrate globally and how they relate with anatomical cortico-subcortical networks is key to understanding how the hu...

Well-established structural abnormalities, mostly involving the limbic system, have been associated with disorders of emotion regulation. Understanding the arrangement and connections of these regions with other functionally specialized cortico-subcortical subnetworks is key to understanding how the human brain's architecture underpins abnormalitie...

Background: Graph theory applied to brain networks is an emerging approach to understanding the brain's topological associations with human cognitive ability. Despite well-documented cognitive impairments in bipolar disorder (BD) and recent reports of altered anatomical network organization, the association between connectivity and cognitive impai...

Manual tracing of magnetic resonance imaging (MRI) represents the gold standard for segmentation in clinical neuropsychiatric research studies, however automated approaches are increasingly used due to its time limitations. The accuracy of segmentation techniques for subcortical structures has not been systematically investigated in large samples....

Background Physical exercise has been shown to improve cognitive and neural functioning in older adults. Aims and methodsThe current study compared the effects of an acute bout of physical exercise with a bout of interactive mental and physical exercise (i.e., “exergaming”) on executive (Stroop) task performance and event-related potential (ERP) am...

Background Although repeatedly associated with white matter microstructural alterations, bipolar disorder (BD) has been relatively unexplored using complex network analysis. This method combines structural and diffusion magnetic resonance imaging (MRI) to model the brain as a network and evaluate its topological properties. A group of highly interc...

Dynamic pricing has been used extensively in specific markets for many years but recent years have seen an interest in the utilization of this approach for the deployment of novel and attractive tariff structures for mobile communication services. This paper describes the development and operation of an agent based model (ABM) for subscriber behavi...

This paper proposes a novel Adaptive Dictionary (AD) reconstruction scheme to improve the performance of Compressed Sensing (CS) with Electrocardiogram (ECG) signals. The method is based on the use of multiple dictionaries, created using Dictionary Learning (DL) techniques for CS signal reconstruction. The modified reconstruction framework is a two...

This paper presents a new approach for modelling the perceptual quality of automotive video corrupted by packet loss. The model uses both temporal and spatial image statistics to distinguish between salient and non-salient packet loss events and hence derive an objective no-reference video quality metric. A new automotive specific video quality dat...

Advances in Compressed Sensing (CS) are enabling promising low-energy implementation solutions for wireless Body Area Networks (BAN). While studies demonstrate the potential of CS in terms of overall energy efficiency compared to state-of-the-art lossy compression techniques, the performance of CS remains limited. The aim of this study is to improv...

The current study examined the effects of cardiorespiratory fitness, identified with a continuous graded cycle ergometry, and aerobic exercise on cognitive functioning and entropy of the electroencephalogram (EEG) in 30 adolescents between the ages of 13 and 14 years. Higher and lower fit participants performed an executive function task after a bo...

This paper proposes a novel approach for detecting and tracking vehicles to the rear and in the blind zone of a vehicle, using a single rear-mounted fisheye camera and multiple detection algorithms. A maneuver that is a significant cause of accidents involves a target vehicle approaching the host vehicle from the rear and overtaking into the adjace...

Previous structural magnetic resonance imaging (S-MRI) studies of bipolar disorder have reported variable morphological changes in subcortical brain structures and ventricles. This study aimed to establish trait-related subcortical volumetric and shape abnormalities in a large, homogeneous sample of prospectively confirmed euthymic bipolar I disord...

This paper proposes a performance test framework for vision based vehicle detection systems implemented on road-going vehicles. An extensive literature review outlines the evolution of test frameworks used by a number of recently published vehicle detection systems. The proposed test framework determines the effectiveness of a detection algorithm a...

Full reference image quality metrics are important tools for optimizing system design parameters associated with image acquisition, compression and transmission. While optimizing systems for perceptual quality is important, in the automotive environment Advanced Driver Assistance Systems (ADAS) such as automated pedestrian detection are becoming a...

Recent research has examined the combination of compressed sensing with over-complete dictionaries for the lossy compression of electrocardiogram (ECG) signals. The application of dictionary learning to automatically create the dictionary is described. A novel analysis of the reconstructed signals using a range of clinical metrics based around QRS...

This paper analyzes the effects of quantization on Compressed Sensing (CS) measurements applied to Electrocardiogram (ECG) signals. Two methods of quantization are proposed in this paper: uniform and non-uniform. Reconstruction is performed using a dictionary based on the Mexican Hat wavelet. A distortion-based performance metric Percent Root-mean-...

We evaluate the effects of transmission artifacts such as JPEG compression and additive white Gaussian noise on the performance of a state-of-the-art pedestrian detection algorithm, which is based on integral channel features. Integral channel features combine the diversity of information obtained from multiple image channels with the computational...

First episode psychosis (FEP) has been associated with structural brain changes, largely identified by volumetric analyses. Advances in neuroimaging processing have made it possible to measure geometric properties that may identify subtle structural changes not appreciated by a measure of volume alone. In this study we adopt complementary methods o...

The analysis of Call Detail Record (CDR) data sets generated by mobile telephony networks has generated much interest in recent years, particularly as an easily accessed source of large volumes of data capable of reflecting the dynamic behavior of humans across a range of temporal and spatial scales. This paper presents a study focused on examining...

This paper provides a comprehensive review of Compressed Sensing or Compressive Sampling (CS) in bioelectric signal compression applications. The aim is to provide a detailed analysis of the current trends in CS, focusing on the advantages and disadvantages in compressing different biosignals and its suitability for deployment in embedded hardware....

Across all biomedical imaging applications, there is a growing emphasis placed on reducing data acquisition and imaging times. This research explores the use of a technique, known as compressive sampling or compressed sensing (CS), as an efficient technique to minimise the data acquisition time for time critical microwave imaging (MWI) applications...

Automotive electronics is a rapidly expanding area with an increasing number of safety, driver assistance, and infotainment devices becoming standard in new vehicles. Current vehicles generally employ a number of different networking protocols to integrate these systems into the vehicle. The introduction of large numbers of sensors to provide drive...

Background: Cryopreservation is of particular importance in stem cell research and regenerative medicine as it permits long term stabilisation of biological cells. Cells retain their regenerative capacity after years of storage at cryogenic temperatures. However, elevation of temperature may occur due to variety of reasons, for example in the even...

This paper proposes a new approach for predicting the Quality of Experience (QoE) of fish-eye to rectilinear transformed images used in automotive vision applications. For this purpose a dataset of automotive images was created. Subjective image quality evaluations of the dataset were carried out, in terms of visual perception and driving assistanc...

The current study examined the effects of physical fitness and aerobic exercise on cognitive functioning and coherence of the electroencephalogram in 30 adolescents between the ages of 13 and 14 years. Participants were first classified as fit or unfit and then performed a modified Eriksen flanker task after a bout of acute exercise and after a per...

Automotive electronics is a rapidly expanding area with an increasing number of driver assistance and infotainment devices becoming standard in new vehicles. A review of current networking standards within vehicles reveals a fragmented and proprietary situation with several standards such as MOST, CAN and LVDS dominating, all of which are currently...

Age-related declines in memory may be due in part to changes in the complexity of neural activity in the aging brain. Electrophysiological entropy provides an accessible measure of the complexity of ongoing neural activity. In the current study, we calculated the permutation entropy of the electroencephalogram (EEG) during encoding of relevant (to...

The current study examined electrophysiological entropy in younger adults, older adults, and older cognitively declined adults across four experimental conditions - eyes closed, eyes open, and during both encoding and recognition of words in a memory task. We hypothesised reduced entropy in older declined adults relative to both older controls and...

Although aging is associated with progressive increases in blood pressure level, previous research has been inconsistent as to whether older adults show greater or lesser cardiovascular reactivity (CVR) to emotion than do younger adults. There is reason to believe that these inconsistencies could be clarified by examining age-related differences in...

This paper addresses the problem of battery life in ambulatory systems for monitoring biomedical signals in the mobile healthcare environment. Specifically, the paper examines the potential power savings that may be obtained using the recently-introduced Bluetooth Low Energy (BLE) specification, where wireless signal transmission is used between a...

Numerous laboratory-based studies have been reported on the use of accelerometry for gait and activity analysis particularly among cohorts of elderly subjects. A drawback of such studies is the use of custom hardware platforms worn by subjects. This paper introduces a system solely utilizing accelerometers embedded in off-the-shelf cellular handset...

This paper proposes a novel non-parametric technique for clustering networks based on their structure. Many topological measures have been introduced in the literature to characterize topological properties of networks. These measures provide meaningful information about the structural properties of a network, but many networks share similar values...

The current study examines the EEG coherence of young, old, and old declined adults performing a visual paired-associates task. In order to examine the effects of encoding context and stimulus repetition, target pairs were presented on either detailed or white backgrounds and were repeatedly presented during both early and late phases of encoding....

This paper proposes a novel non-parametric technique for clustering networks based on their structure. Many topological measures have been introduced in the literature to characterize topological properties of networks. These measures provide meaningful information about the structural properties of a network, but many networks share similar values...

Network delay, packet loss and network delay variability (jitter) are important factors that impact on perceived voice quality in VoIP networks. An adaptive playout buffer is used in a VoIP terminal to overcome jitter. Such a buffer-control must operate a trade-off between the buffer-induced delay and any additional packet loss rate. In this paper,...

One likely mechanism in learning new skills is change in synchronous connections between distributed neural networks, which can be measured by coherence analysis of electroencephalographic patterns. This study examined coherence changes during the learning of two tasks, a word association task and a figure association task. Although learning curves...

This paper provides a case study of a service learning based project module which has been integrated into the under-graduate degree programmes delivered by the Electrical & Electronic Engineering discipline within the College of Engineering and Informatics at the National University of Ireland, Galway. Community based service learning has long bee...

Numerous laboratory based studies have been reported on the use of accelerometry for gait and activity analysis. A drawback of such studies is the use of custom hardware platforms worn by subjects. This paper introduces a system solely utilising accelerometers embedded in off-the-shelf cellular handsets which allow medical professionals and caregiv...

A number of different protocols have been proposed to support the concept of wireless terminal mobility. One such protocol is SCTP which includes functionality to monitor the characteristics of the primary path and all alternate secondary paths connecting two hosts. This supports a basic mechanism by which traffic can be switched from a primary pat...

Over the last decade, there has been substantial research interest in the application of accelerometry data for many forms of automated gait and activity analysis algorithms. This paper introduces a summary of new "of-the-shelf" mobile phone handset platforms containing embedded accelerometers which support the development of custom software to imp...

This paper describes a study which was carried out to determine an optimally performing classification algorithm for the problem of subject independent gait pattern classification. The study utilised a frequency domain based feature vector based on the concept of cepstral coefficients whose generation methodology was optimised in terms of overall s...

Accelerometry has been shown to be a good tool for ambulatory activity monitoring. This paper describes the use of spectral features for classification of gait activities based on accelerometric data. The classification is performed by a Gaussian mixture model (GMM) based statistical classifier at the back end. Fifty subjects participated in the ex...

The statistical nature of data traffic and the dynamic routing techniques employed in IP networks results in a varying network delay (jitter) experienced by the individual IP packets which form a VoIP flow. As a result voice packets generated at successive and periodic intervals at a source will typically be buffered at the receiver prior to playba...

Monitoring methods relating to the service levels provided to subscribers of second and third generation mobile networks have traditionally focused on a mixture of simulation and "drive testing". This approach, while it has served its purpose, has proved inefficient and arguably inadequate. The system outlined in this paper proposes placing a small...

Playout delay adaptation algorithms are often used in real time voice communication over packet-switched networks to counteract the effects of network jitter at the receiver. Whilst the conventional algorithms developed for silence-suppressed speech transmission focused on preserving the relative temporal structure of speech frames/packets within a...

The commercial deployment of voice over internet protocol (VoIP) networks (and associated packet switching technologies) has gathered pace in the recent years. However, a major concern with such networks is the issue of the security of networks based on such open standards. Little research has been carried out into examining the options for securin...

This research focuses on the impact of different Internet Key Exchange (IKE) protocols under the performance perspective in a secure VoIP (Voice over IP) network environment. The key exchange plays a vital role between parties who utilise an end-to-end encryption protocol to secure their communication channels. The IKE setup time to negotiate the s...

This paper outlines research which has been carried out into the development of a technique for the automatic identification of the occurrence of certain types of distortions occurring in a VoIP network. This type of a technique could be used as a pre-processor for a non-intrusive perceptual speech quality measurement technique. The proposed techni...

This paper describes an FPGA and distributed RAM architecture for an image pixel processor implementing primary elements of an object detection system. A comparison of the system performance with existing DSP processor-based alternatives is detailed. An implementation using the RC1000-PP FPGA-based development platform and Handel-C hardware program...

This paper describes an FPGA and distributed RAM architecture for an image classifier, implementing object classification stages of an object detection system. The system offers significant performance increase over current programmable DSP-based implementations. The paper shows that the considerable performance improvement using the FPGA solution...

This paper presents our experience in teaching Digital Signal Processing (DSP) in Irish university undergraduate and postgraduate courses, as well as some limited experience of teaching DSP in Australia to undergraduate students. We also present the methodology used in designing and the delivery of the module. Our experience of various methods of d...

The development of value added services based upon the GSM standard is becoming increasingly important to both network operators and the subscriber's to such networks. This paper outlines a system capable of delivering “real time” stock price information (e.g. price, volume etc.) from Internet based stock price servers to a variety of subscriber ty...

The development of value added services based upon the GSM standard is becoming increasingly important to both network operators and the subscriber's to such networks. This paper outlines a prototype system capable of delivering real time stock (share) price information from Internet based stock price servers to mobile subscribers equipped with GSM...

This paper outlines four novel methods for the task of speaker verification. The first model, a Hybrid Multi-Layer Perceptron (MLP)-Radial Basis Function (RBF) model, is an MLP predictor whose weights are then used as inputs to an RBF classifier for the verification process. The second model uses an array of linear predictors to model the true spea...

Recent technological advances have allowed great enhancements in the quality of service provided to subscribers by mobile telephony network operators. A key requirement in enhancing a subscriber's experience of utilising the services provided by such networks is the ability for the network operator to gather reliable information relating to the cus...

This paper outlines research focused on the development of a non-intrusive methodology for the identification of speech distortions in packet-based transmission systems, e.g., voice-over-IP (VoIP) networks. In this field, speech quality degradation due to packet loss is of most interest. Methods presented in the paper focus on the localisation of a...

This paper outlines research which has been carried out to compare the performance of IKEv1 and IKEv2 protocols when used to secure a VoIP network. An OPNET based model of such a secure network was used as the test bed for carrying out these simulations. Results are presented outlining the relative performances of the IKE versions in this network e...

Monitoring methods relating to the service levels provided to subscribers of second and third generation mobile networks have traditionally focused on a mixture of simulation and "drive testing". This approach, while it has served its purpose, has proved inefficient and arguably inadequate. The system outlined in this paper proposes placing a small...

A two stage neural architecture model is proposed in this paper for the task of speaker verification. This model operates solely in the time domain and hence removes the need for any computationally demanding pre-processing of the input speech signal. The first stage in the model is a Multi-Layer Perceptron (MLP) based non-linear speech predictor....