Charles Gillan - Academia.edu (original) (raw)

Papers by Charles Gillan

IntechOpen eBooks, Aug 4, 2020

The Internet has become an essential part of daily life for almost everyone in society having gro... more The Internet has become an essential part of daily life for almost everyone in society having grown far beyond its roots in the 1970s as the ARPANET, a network that was principally the domain of scientists and engineers. The popularity of the HTTP, developed at CERN in the late 1980s led to the widespread use of the term 'the web' as a generic name for the Internet for many years, at least in the public domain. Of course, the Internet is much more than just web browsing and, in recent years, the term cyberspace has become the most popular term to describe interactions over the Internet. Yet, an unambiguous definition of the term is difficult to formulate. Financial institutions underpinning the economy and the operation of national critical infrastructures, such as monitoring and control of the electricity supply, are now dependent on the Internet. A consequence of this is that cyberattacks become more costly for the victims and perversely more attractive to the criminals who carry them out. The advent of the Internet of Things (IoT) and edge computing as a new paradigm creates the potential for enhanced productivity but at the same time opens up new opportunities for cyberattacks while still being exposed to existing attach vectors such as the well-known denial of service attack (DDoS), which can take place in many forms. In this chapter, we described the challenges in building an edge system that is secure against cyberattack. We begin by briefly reviewing the architecture of communications over the Internet and later consider the new challenges that follow from operating the hardware with values of voltage, frequency and current that enable more energy efficiency.

The typical operating frequency of modern high frequency electronic circuits constructed on galli... more The typical operating frequency of modern high frequency electronic circuits constructed on gallium arsenide (GaAs) and silicon for radar and broadband wireless applications is several GigaHertz, that is in the microwave region, making the wavelength of the electromagnetic signals present comparable with the dimensions of the circuit itself. Under these conditions, the geometry of the circuit, and the packaging surrounding it, will significantly influence the operational characteristics of the device. Thus, a detailed knowledge of the electromagnetic fields present is essential to perform accurate circuit design.

2021 IEEE 17th International Conference on eScience (eScience), 2021

Recent research shows that, in addition to the universal approximation function, neural networks ... more Recent research shows that, in addition to the universal approximation function, neural networks are capable of accurately approximating the mapping, both linear and non-linear, of one space of continuous functions into another. We report on our experience of coupling a well known CFD code, OpenFOAM, to neural network modelling using TensorFlow on a HPC system in order to model tank transfer functions. The CFD stage is well suited to using multiple CPUs via MPI libraries while the machine learning stage is better suited to using GPUs via several Python packages and libraries. We report that these distinct steps can be joined into an efficient pipeline by using the file system effectively. Our results show that neural network modelling works well in the region where non-linear CFD theories are needed to model the dynamics of water waves.

Journal of physics, Sep 14, 1987

The differential elastic and vibrationally inelastic cross sections for e(-)-N2 scattering are ca... more The differential elastic and vibrationally inelastic cross sections for e(-)-N2 scattering are calculated in the energy range from threshold to 30 eV using the R-matrix method. At low energies the cross sections are dominated by the well known 2Pi(g) resonance. In this energy region nonadiabatic effects due to the coupling of the electronic and nuclear degrees of freedom are included.

Journal of Physics B, Sep 28, 1997

A new computer program has been developed which allows us to use the R-matrix method to study ele... more A new computer program has been developed which allows us to use the R-matrix method to study electron scattering by polyatomic molecules. Our first application is to scattering by 0953-4075/30/18/010/img8 in its linear, equilibrium geometry for energies up to 10 eV. We confirm the earlier assignment of 0953-4075/30/18/010/img9 symmetry to the resonance near 2 eV but we are unable to

Physical Review A, Mar 1, 1993

Ab initio calculations are performed on the e--He+2 complex using the R-matrix technique. A two-s... more Ab initio calculations are performed on the e--He+2 complex using the R-matrix technique. A two-state approximation is utilized in which the 2Sigma+u and the A 2Sigma+g electronic states of He+2, in the close-coupling expansion, are represented by truncated configuration-interaction (CI) wave functions obtained from multiconfiguration-self-consistent-field-complete-active-space-SCF (MCSCF-CASSCF) calculations. A (4s,2p,2d) Slater basis is used to perform bound-state calculations at SCF, full

Springer eBooks, 1995

... present scheme Slater Type Functions (36) oefncients whose rix theory lies in ted only once f... more ... present scheme Slater Type Functions (36) oefncients whose rix theory lies in ted only once for oint oí view of a .pters 2 and 5. A e subiect matter :on outlining the ady of any ... The finai structure of the orbital matrix С is illustrated in figure 2 where its mor-phology is cleariy visible. ...

APS Division of Atomic, Molecular and Optical Physics Meeting Abstracts, May 1, 1996

Abstract The R-matrix method has been used to study low energy electronic excitation of diatomics... more Abstract The R-matrix method has been used to study low energy electronic excitation of diatomics by electrons. Recent calculations on nitrogen considered both differential and integral cross sections arising from excitation to the lowest seven electronically excited states of the system. These calculations resolved several of the discrepencies with experiment found in previous theoretical studies, although disagreements remain over differential excitation cross sections. A new algorithm has been developed which should ...

NATO advanced study institutes series, 1993

We report in this paper ab initio calculations of He2(1,3Σ g + ) bound states, autoionization wid... more We report in this paper ab initio calculations of He2(1,3Σ g + ) bound states, autoionization widths and resonance positions. The calculations have been carried using the R-matrix method to study low energy elastic scattering of electrons from He 2 + molecular ions. To our knowledge no other methods have been used for scattering calculations on this system nor have there been experimental measurements of the process. For the continuum states there exists no experimental data and little theoretical work with which to compare our results at this time. This work is an extension of the recent work by McLaughlin et al. 23 on the 3Σ u + scattering symmetry in e−− He 2 + collisions.

Journal of Physics B: Atomic, Molecular and Optical Physics, 1996

Abstract. Ab initio calculations are performed on the e−–N2 scattering system, at low impact ener... more Abstract. Ab initio calculations are performed on the e−–N2 scattering system, at low impact energies, using the R-matrix technique. The X 1+ g ground state and the lowest seven valence excited states, A 3+ u, B 3 g, W 3 u, B 3− u, a 1− u, a 1 g and w 1 u, of N2 are included in the close coupling expansion with each state being represented by a configuration interaction wavefunction in a hybrid orbital set. Various approximations for the representation of the correlation between the target and the incident electron are ...

Zenodo (CERN European Organization for Nuclear Research), May 10, 2018

A new methodology is proposed to compare database performance for streams of patient respiratory ... more A new methodology is proposed to compare database performance for streams of patient respiratory data from patients in an intensive care unit. New metrics are proposed through which databases may be compared both for this and similar streaming applications in the domain of the Internet of Things. Studies are reported using simulated patient data for four freely available databases. The statistical technique of nonparametric bootstrapping is used to minimise the total running time of the tests. We report mean values and bias corrected and accelerated confidence intervals for each metric and use these to compare the databases. We find that, among the four databases tested, ScaleDB is an optimum database technology when handling between 200 and 800 patients in this application, while PostgreSQL performs best outside of this range. Comparing the non-parametric bootstrapping method to a complete set of tests shows that the two approaches give results differing by a few percent.

Springer eBooks, 2022

Computer systems deployed in hospital environments, particularly physiological and biochemical re... more Computer systems deployed in hospital environments, particularly physiological and biochemical real-time monitoring of patients in an Intensive Care Unit (ICU) environment, routinely collect a large volume of data that can hold very useful information. However, the vast majority are either not stored and lost forever or are stored in digital archives and seldom reexamined. In recent years, there has been extensive work carried out by researchers utilizing Machine Learning (ML) and Artificial Intelligence (AI) techniques on these data streams, to predict and prevent disease states. Such work aims to improve patient outcomes, to decrease mortality rates and decrease hospital stays, and, more generally, to decrease healthcare costs. This chapter reviews the state of the art in that field and reports on our own current research, with practicing clinicians, on improving ventilator weaning protocols and lung protective ventilation, using ML and AI methodologies for decision support, including but not limited to Neural Networks and Decision Trees. The chapter considers both the clinical and Computer Science aspects of the field. In addition, we look to the future and report how physiological data holds clinically important information to aid in decision support in the wider hospital environment.

Informatics in Medicine Unlocked, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

IEEE Transactions on Multi-Scale Computing Systems, 2018

Ever increasing power consumption has created great interest in energy-efficient microserver arch... more Ever increasing power consumption has created great interest in energy-efficient microserver architectures but they lack the computational, networking and storage power necessary to cope with real-time data analytics. We propose NanoStreams, an integrated architecture comprising an ARM-based microserver, coupled via a novel, low latency network interface, Nanowire, to a Analytics-on-Chip architecture implemented on Field Programmable Gate Array (FPGA) technology; the architecture comprises ARM cores for performing low latency transactional processing, integrated with programmable, energy efficient Nanocore processors for high-throughput streaming analytics. The paper outlines the complete system architecture, hardware level detail, compiler, network protocol, and programming environment. We present experiments with an industrial workload from the financial services sector, comparing a state-of-the-art server based on Intel Sandy Bridge processors, an ARM based Calxeda ECS-1000 microserver and ODROID XU3 node, with the NanoStreams microserver architecture. For end-to-end workload, the NanoStreams microserver achieves energy savings up to 10.7×, 5.87× and 5× compared to the Intel server, Calxeda microserver and ODROID node respectively.

BMJ Open

IntroductionElectronic clinical decision support (eCDS) tools are used to assist clinical decisio... more IntroductionElectronic clinical decision support (eCDS) tools are used to assist clinical decision making. Using computer-generated algorithms with evidence-based rule sets, they alert clinicians to events that require attention. eCDS tools generating alerts using nudge principles present clinicians with evidence-based clinical treatment options to guide clinician behaviour without restricting freedom of choice. Although eCDS tools have shown beneficial outcomes, challenges exist with regard to their acceptability most likely related to implementation. Furthermore, the pace of progress in this field has allowed little time to effectively evaluate the experience of the intended user. This scoping review aims to examine the development and implementation strategies, and the impact on the end user of eCDS tools that generate alerts using nudge principles, specifically in the critical care and peri-anaesthetic setting.Methods and analysisThis review will follow the Arksey and O’Malley f...