• CAP: Patching the Human Vulnerability

      Eze, Thaddeus; Hawker, Neil; University of Chester
      Cyber threats to organisations across all industries are increasing in both volume and complexity, leading to significant, and sometimes severe, conse-quences. The common weakest link in organisations security is the human vulnerability. The sudden popularity of remote-working due to the Covid-19 pandemic opened organisations and their employees up to more risks, partic-ularly as many workers believe that they are more distracted when at home. Existing cyber training using a ‘one-size-fits-all’ approach has been proven inefficient/ineffective and the need for a more fit-for-purpose training is re-quired. When it comes to cyber training, we know that there is no single-training-fits-all solution – people have different technical skills, different prior knowledge and experience, are in different roles, exposed to different security risks, and require knowledge that is relevant to what they do. This study makes a case for tailored role-based cybersecurity training suitable for awareness within organisations across multiple industries. The study ex-plores the strengths and weaknesses of existing cyber training and literature to make recommendations on efficient awareness and training programme strategies. The study carries out knowledge and task analysis of job roles to create profiles of skills and knowledge they require. These are grouped by topic and level to form scenario-based multiple-choice questions which are mapped to create a Cyber Awareness Platform (CAP). A CAP prototype is in-troduced as a flexible web-based system allowing users to assess their prior knowledge and skills personalised to their role. Knowledge gaps and training needs are identified, and recommendations are tailored to the individual. Ini-tial analysis of CAP shows promising results, indicating that such role-sensitive solution would be highly beneficial to users. This offers further de-velopment opportunities in producing an all-in-one cyber assessment and training platform.
    • Forensic Trails Obfuscation and Preservation via Hard Drive Firmware

      Underhill, Paul; Oyinloye, Toyosi; Eze, Thaddeus; Speakman, Lee; University of Chester; University of Salford (Academic Conferences International, 2022-06-08)
      The hard disk drive stores data the user is creating, modifying, and deleting while a firmware facilitates communication between the drive and the operating system. The firmware tells the device and machine how to communicate with each other and will share useful information such as, disk size and information on any bad sectors. Current research shows that exploits exist that can manipulate these outputs. As an attacker, you can change the size of the disk displayed to the operating system to hide data in, likewise by marking an area of the disk as bad. Users may not be aware of these changes as the operating system will accept the readings from the firmware. However, although the data is not reachable via the operating system this paper looks at the traceability of manipulated data using data recovery software FTK Imager, Recuva, EaseUS and FEX Imager. This report examines the use of malicious techniques to thwart digital forensic procedures by manipulating the firmware. It is shown how this is possible and current forensic techniques or software does not easily detect a change within the firmware. However, with the use of various forensic tools, obfuscated trails are detectable. This report follows a black box testing methodology to show the validation of forensic tools or software against anti-forensic techniques. The analysis of the results showed that most tools can find the firmware changes, however, it requires an analyst to spot the subtle differences between standard and manipulated devices. The use of multiple software tools can help an analyst spot the inconsistencies.
    • Resolving nanoscopic structuring and interfacial THz dynamics in setting cements

      Song, Fu V.; Yang, Bin; Di Tommaso, Devis; orcid: 0000-0002-4485-4468; Donnan, Robert S.; Chass, Gregory A.; orcid: 0000-0002-5265-6672; Yada, Rickey Y.; Farrar, David H.; Tian, Kun V.; orcid: 0000-0003-0102-0620 (Royal Society of Chemistry (RSC), 2022)
      The setting dynamics of commercial cements were tracked non-destructively by THz spectroscopy probing interfacial dynamics and neutron scattering resolving structural evolutions over 1–30 nm, with trends made comprehensible by computational models.
    • Electrical resistance tomography-based multi-modality sensor and drift flux model for measurement of oil–gas–water flow

      Rashed, Sara; orcid: 0000-0003-1518-0596; Faraj, Yousef; orcid: 0000-0003-4418-3649; email: y.faraj@chester.ac.uk; Wang, Mi; Wilkinson, Stephen (IOP Publishing, 2022-06-14)
      Abstract: This paper proposes a novel method to measure each constituent of an oil–gas–water mixture in a water continuous flow, typically encountered in many processes. It deploys a dual-plane electrical resistance tomography sensor for measuring dispersed phase volume fraction and velocity; a gradiomanometer flow density meter and a drift flux model to estimate slip velocities; with absolute pressure and temperature measurements. These data are fused to estimate constituent volume flow rates. Other commonly used operational parameters can be further derived: water cut or water liquid ratio (WLR) and gas volume fraction (GVF). Trials are described for flow rates of water 5–10 m3 h−1; oil 2–10 m3 h−1 and gas 1–15 m3 h−1. The comparative results are included with published data from the Schlumberger Gould Research flow facility. The paper proposes the use of the described configuration for measurement of volume flow rates in oil–gas–water flows with an absolute error of ±10% within GVF 9%–85% and WLR > 45%.
    • Binary self-dual and LCD codes from generator matrices constructed from two group ring elements by a heuristic search scheme

      Dougherty, Steven; Korban, Adrian; Șahinkaya, Serap; Ustun, Deniz (American Institute of Mathematical Sciences (AIMS), 2022)
      <p style='text-indent:20px;'>We present a generator matrix of the form <inline-formula><tex-math id="M1">\begin{document}$ [ \sigma(v_1) \ | \ \sigma(v_2)] $\end{document}</tex-math></inline-formula>, where <inline-formula><tex-math id="M2">\begin{document}$ v_1 \in RG $\end{document}</tex-math></inline-formula> and <inline-formula><tex-math id="M3">\begin{document}$ v_2\in RH $\end{document}</tex-math></inline-formula>, for finite groups <inline-formula><tex-math id="M4">\begin{document}$ G $\end{document}</tex-math></inline-formula> and <inline-formula><tex-math id="M5">\begin{document}$ H $\end{document}</tex-math></inline-formula> of order <inline-formula><tex-math id="M6">\begin{document}$ n $\end{document}</tex-math></inline-formula> for constructing self-dual codes and linear complementary dual codes over the finite Frobenius ring <inline-formula><tex-math id="M7">\begin{document}$ R $\end{document}</tex-math></inline-formula>. In general, many of the constructions to produce self-dual codes forces the code to be an ideal in a group ring which implies that the code has a rich automorphism group. Unlike the traditional cases, codes constructed from the generator matrix presented here are not ideals in a group ring, which enables us to find self-dual and linear complementary dual codes that are not found using more traditional techniques. In addition to that, by using this construction, we improve <inline-formula><tex-math id="M8">\begin{document}$ 10 $\end{document}</tex-math></inline-formula> of the previously known lower bounds on the largest minimum weights of binary linear complementary dual codes for some lengths and dimensions. We also obtain <inline-formula><tex-math id="M9">\begin{document}$ 82 $\end{document}</tex-math></inline-formula> new binary linear complementary dual codes, <inline-formula><tex-math id="M10">\begin{document}$ 50 $\end{document}</tex-math></inline-formula> of which are either optimal or near optimal of lengths <inline-formula><tex-math id="M11">\begin{document}$ 41 \leq n \leq 61 $\end{document}</tex-math></inline-formula> which are new to the literature.</p>
    • A numerical exercise on waste incineration

      Jones, J C; orcid: 0000-0001-6507-5861; email: john.jones@chester.ac.uk (IOP Publishing, 2022-06-07)
      Abstract: A numerical example for tutorial and possibly design exercise use is described which is concerned with the performance of household waste as a fuel in power generation.
    • Aircraft Electrical Propulsion for High-Speed Flight: Rim Driven Fan (RDF) Technology

      Vagapov, Yuriy; Day, Richard; Anuchin, Alecksey; Bolam, Robert C. (University of ChesterWrexham Glyndŵr University, 2021-02)
      The aim of this programme of studies is to research and develop electrical Rim Driven Fan (RDF) technology for high-speed aircraft propulsion and to provide knowledge to support Society’s efforts to combat climate change using zero-emission technologies. The objectives were to conduct research into the state-of-the-art of aircraft electrical propulsion, to estimate the performance of single and dual stage contra-rotating fans over a range of diameters, to provide a methodology to enable the aerodynamic design and detailed Computational Fluid Dynamic (CFD) analyses of small contra-rotating fans and to create a conceptual design for an RDF device suitable to power an unmanned aircraft. In completing this work, literature reviews were carried out on electrically powered propulsion for aircraft, electrical motor technologies and rim drive technology for aircraft propulsion. Original research was undertaken in the form of aerodynamic analyses, using derived numerical and CFD techniques, to determine the optimum performance of single and dual stage (contrarotating) rim driven fans for high-speed electric aircraft applications. Original research was also undertaken in the form of electrical analyses using Motor-CAD finite element software to analyse the feasibility of novel rim-drive concepts such as slotless stator designs, aluminium windings and iron-less rotors with Halbach magnet arrays in an RDF context. The results of these studies have contributed new knowledge that has been peer-reviewed and internationally published. An original RDF design concept, suitable to power an unmanned aircraft, was devised and a UK patent application filed. The main findings of this work are that RDF technology offers a viable means of high-speed aircraft propulsion with a dual-stage contrarotating, air-cooled fan arrangement. That optimum RDF power density is achieved with slotless windings and iron-less rotors configured with Halbach magnet arrays which reduce their rotating mass. These findings have enabled a feasible novel RDF design to be created which is a significant contribution in the field of electrical aircraft propulsion. The results of this work also contribute the significant new knowledge that dual stage contra-rotating RDF configurations provide the potential for an increase in thrust per frontal area, and higher exhaust-air velocities, when compared with existing hub-driven fan technologies. This work has established a novel fan design technique, that can be used by technologists to analyse and design future electrical fan concepts, and offers a significant contribution towards Society’s efforts to combat climate change with zero-emission technologies. Opportunities for further areas of study in this field are in the analyses of large diameter high thrust versions of RDFs suitable for large manned aircraft and hovercraft applications.
    • Numerical methods for Caputo-Hadamard fractional differential equations with graded and non-uniform meshes

      Green, Charles; Liu, Yanzhi; Yan, Yubin; University of Chester; Lvliang University
      We consider the predictor-corrector numerical methods for solving Caputo-Hadamard fractional differential equation with the graded meshes $\log t_{j} = \log a + \big ( \log \frac{t_{N}}{a} \big ) \big ( \frac{j}{N} \big )^{r}, \, j=0, 1, 2, \dots, N$ with $a \geq 1$ and $ r \geq 1$, where $\log a = \log t_{0} < \log t_{1} < \dots < \log t_{N}= \log T$ is a partition of $[\log t_{0}, \log T]$. We also consider the rectangular and trapezoidal methods for solving Caputo-Hadamard fractional differential equation with the non-uniform meshes $\log t_{j} = \log a + \big ( \log \frac{t_{N}}{a} \big ) \frac{j (j+1)}{N(N+1)}, \, j=0, 1, 2, \dots, N$. Under the weak smoothness assumptions of the Caputo-Hadamard fractional derivative, e.g., $\prescript{}{CH}D^\alpha_{a,t}y(t) \notin C^{1}[a, T]$ with $ \alpha \in (0, 2)$, the optimal convergence orders of the proposed numerical methods are obtained by choosing the suitable graded mesh ratio $r \geq 1$. The numerical examples are given to show that the numerical results are consistent with the theoretical findings.
    • Weak convergence of the L1 scheme for a stochastic subdiffusion problem driven by fractionally integrated additive noise

      Hu, Ye; Li, Changpin; Yan, Yubin; University of Chester; Lvliang University; Shanghai University
      The weak convergence of a fully discrete scheme for approximating a stochastic subdiffusion problem driven by fractionally integrated additive noise is studied. The Caputo fractional derivative is approximated by the L1 scheme and the Riemann-Liouville fractional integral is approximated with the first order convolution quadrature formula. The noise is discretized by using the Euler method and the spatial derivative is approximated with the linear finite element method. Based on the nonsmooth data error estimates of the corresponding deterministic problem, the weak convergence orders of the fully discrete schemes for approximating the stochastic subdiffusion problem driven by fractionally integrated additive noise are proved by using the Kolmogorov equation approach. Numerical experiments are given to show that the numerical results are consistent with the theoretical results.
    • 2D‐Hexagonal Boron Nitride Screen‐Printed Bulk‐Modified Electrochemical Platforms Explored towards Oxygen Reduction Reactions

      Khan, Aamar; Ferrari, Alejandro Garcia-Miranda; Hughes, Jack; Smith, Graham C; Banks, Craig E; Rowley-Neale, Samuel J; Manchester Metropolitan University; University of Chester (MDPI, 2022-04-26)
      A low‐cost, scalable and reproducible approach for the mass production of screen‐printed electrode (SPE) platforms that have varying percentage mass incorporations of 2D hexagonal boron nitride (2D‐hBN) (2D‐hBN/SPEs) is demonstrated herein. These novel 2D‐hBN/SPEs are explored as a potential metal‐free electrocatalysts towards oxygen reduction reactions (ORRs) within acidic media where their performance is evaluated. A 5% mass incorporation of 2D‐hBN into the SPEs resulted in the most beneficial ORR catalysis, reducing the ORR onset potential by ca. 200 mV in comparison to bare/unmodified SPEs. Furthermore, an increase in the achievable current of 83% is also exhibited upon the utilisation of a 2D‐hBN/SPE in comparison to its unmodified equivalent. The screen‐printed fabrication approach replaces the less‐reproducible and time‐consuming dropcasting technique of 2D‐hBN and provides an alternative approach for the large‐scale manufacture of novel electrode platforms that can be utilised in a variety of applications
    • Visualization for Epidemiological Modelling: Challenges, Solutions, Reflections & Recommendations

      Dykes, Jason; Abdul-Rahman, Alfie; Archambault, Daniel; Bach, Benjamin; Borgo, Rita; Chen, Min; Enright, Jessica; Fang, Hui; Firat, Elif E.; Freeman, Euan; et al.
      We report on an ongoing collaboration between epidemiological modellers and visualization researchers by documenting and reflecting upon knowledge constructs – a series of ideas, approaches and methods taken from existing visualization research and practice – deployed and developed to support modelling of the COVID-19 pandemic. Structured independent commentary on these efforts is synthesized through iterative reflection to develop: evidence of the effectiveness and value of visualization in this context; open problems upon which the research communities may focus; guidance for future activity of this type; and recommendations to safeguard the achievements and promote, advance, secure and prepare for future collaborations of this kind. In describing and comparing a series of related projects that were undertaken in unprecedented conditions, our hope is that this unique report, and its rich interactive supplementary materials, will guide the scientific community in embracing visualization in its observation, analysis and modelling of data as well as in disseminating findings. Equally we hope to encourage the visualization community to engage with impactful science in addressing its emerging data challenges. If we are successful, this showcase of activity may stimulate mutually beneficial engagement between communities with complementary expertise to address problems of significance in epidemiology and beyond. https://ramp-vis.github.io/RAMPVIS-PhilTransA-Supplement/
    • Multi-metric Evaluation of the Effectiveness of Remote Learning in Mechanical and Industrial Engineering During the COVID-19 Pandemic: Indicators and Guidance for Future Preparedness, 2021

      Behera, Amar Kumar; de Sousa, Ricardo Alves; Oleksik, Valentin; Dong, Jingyan; Fritzen, Daniel; University of Chester; University of Aveiro; Lucian Blaga University of Sibiu; North Carolina State University; SATC College, Criciuma
      This data set is a follow on study from a study on remote learning conducted in 2020 during the first year of the COVID-19 pandemic. It contains data collected from 5 universities in 5 countries about the effectiveness of e-learning during the COVID-19 pandemic in 2021, specifically tailored to mechanical and industrial engineering students. A survey was administered in August 2021 at these universities simultaneously, using Google Forms. The survey had 41 questions, including 24 questions on a 5-point Likert scale. The survey questions gathered data on their program of study, year of study, university of enrolment and mode of accessing their online learning content. The Likert scale questions on the survey gathered data on the effectiveness of digital delivery tools, student preferences for remote learning and the success of the digital delivery tools during the pandemic. All students enrolled in modules taught by the authors of this study were encouraged to fill the survey up. Additionally, remaining students in the departments associated with the authors were also encouraged to fill up the form through emails sent on mailing lists. The survey was also advertised on external websites such as survey circle and facebook. Crucial insights have been obtained after analysing this data set that link the student demographic profile (gender, program of study, year of study, university) to their preferences for remote learning and effectiveness of digital delivery tools. This data set can be used for further comparative studies and was useful to get a snapshot of the evolution of the student preferences and e-learning effectiveness during the COVID-19 pandemic from 2020 to 2021 by comparing with the dataset from 2020.
    • A survey of modern deep learning based object detection models

      Zaidi, Syed Sahil Abbas; Ansari, Mohammad Samar; Aslam, Asra; Kanwal, Nadia; Asghar, Mamoona; Lee, Brian; Technological University of the Shannon; University of Chester; National University of Ireland; Keele University; Lahore College for Women University (Elsevier, 2022-03-08)
      Object Detection is the task of classification and localization of objects in an image or video. It has gained prominence in recent years due to its widespread applications. This article surveys recent developments in deep learning based object detectors. Concise overview of benchmark datasets and evaluation metrics used in detection is also provided along with some of the prominent backbone architectures used in recognition tasks. It also covers contemporary lightweight classification models used on edge devices. Lastly, we compare the performances of these architectures on multiple metrics.
    • Immersive Virtual Reality for the Cognitive Rehabilitation of Stroke Survivors

      Chatterjee, Kausik; Buchanan, Alastair; Cottrell, Katy; Hughes, Sara; Day, Thomas W.; John, Nigel W.; Countess of Chester Hospital NHS Foundation Trust; Cadscan Limited; University of Chester (IEEE, 2022-03-10)
      We present the results of a double-blind phase 2b randomized control trial that used a custom built virtual reality environment for the cognitive rehabilitation of stroke survivors. A stroke causes damage to the brain and problem solving, memory and task sequencing are commonly affected. The brain can recover to some extent, however, and stroke patients have to relearn how to carry out activities of daily living. We have created an application called VIRTUE to enable such activities to be practiced using immersive virtual reality. Gamification techniques enhance the motivation of patients such as by making the level of difficulty of a task increase over time. The design and implementation of VIRTUE is described together with the results of the trial conducted within the Stroke Unit of a large hospital. We report on the safety and acceptability of VIRTUE. We have also observed particular benefits of VR treatment for stroke survivors that experienced more severe cognitive impairment, and an encouraging reduction in time spent in the hospital for all patients that received the VR treatment.
    • Insights into the Analysis of Fractional Delay Differential Equations

      Ford, Neville; Osborne, Neil (University of Chester, 2021-07)
      This thesis is concerned with determining the analytic solution, using the method of steps, of the following fractional delay differential equation initial interval problem (FDDE IIP), c Dαy(s) = −y(t − τ ) for t > 0, τ > 0, 0 < α < 1, and y ∈ A1(0, T ] 0 t y(t) = ϕ(t) for t ∈ (−τ, 0] The properties of the analytic solution obtained are a surprise but they do sit comfortably when compared with those of the analytic solutions of an ordinary differential equation initial value problem (ODE IVP), a delay differential equation initial interval problem (DDE IIP) and an fractional ordinary differential equation initial value problem (FODE IVP). Further the analytic solution formula obtained is closely related to that of the analytic solution formula of the DDE IIP. However, these insights into the analytic solution of the FDDE IIP we have not seen before, and differ from those published elsewhere.
    • Towards Effective Project Management and Knowledge Transfer Enhancement: A Novel System Capturing and Modelling Knowledge Acquired in a Software Development Practice

      Kerins, John; Rayner, Linda; John, Nigel; Fannoun, Sufian (University of Chester, 2021-03)
      The practice of software project management evolves alongside emerging new technologies such as advances in new tools and resources in Application Programming Interfaces (APIs) and machine learning applications. This thesis evaluates the ways in which a small software development unit, characteristics of other small enterprises, has embraced emerging trends in the development of digital technologies in order to establish and maintain successful practice. A qualitative research approach was adopted to elicit an understanding of the critical knowledge acquired as the unit developed and its members become effective practitioners. The research identifies and analyses the acquired knowledge that underpins successful practice, and uses the results of this analysis to propose a support system to enhance future practice. This is a challenge is that there is limited evidence of Small and Medium Enterprises (SMEs) engaging in knowledge management (KM) or in organisational learning (OL) initiatives. In developing projects, smaller software development organisations rely on implicit knowledge and Agile to resolve complexity. Consequently, and specifically in a small business, the development of this bespoke system, represents a novel approach to Knowledge Management (KM) and Organisational Learning (OL). Projects were identified as key sources and locus of development, innovation knowledge, skills, know-how and learning within the unit. This outcome has reinforced the proposal for a links-based system around individual projects. As in Chapter Nine, the system is as a web-based repository of project templates. The templates capture key insights into critical decisions and significant advances in current practice that arise from work within individual projects. The proposed system captures the unit’s knowledge. In addition, it provides an accessible resource that not only supports critical reflection and decision making but also retains key aspects of organisational learning (OL) and know-how. Further, while complementing continuing implicit learning, it has the further benefit of maintaining organisational resilience where individuals’ skills may be lost or where the unit faces high staff turnover. Moreover, the system can serve to induct newcomers to the unit. Accordingly, for a small software development unit with no prior knowledge management initiative or system in place, the research’s immediate contribution is through modelling, capturing and representing the acquired knowledge. This thesis provides insights into the management of software project knowledge through web technology. The prototype was successfully designed, implemented, evaluated and made available to the research unit working group. Such a system provides an effective measure for application at organisational and project levels, the evaluation of practice and the reuse of project knowledge to improve performance and effective practice. A further contribution made by this research is in revealing the range of the acquired knowledge, the know-how and the soft skills that complement the technical skills of software development within the research unit. The set of know-how and soft skills could be valuable where measures for effective professional practice are required. The analysed data revealed the range of capabilities the members developed to enable the application of implicit knowledge. Such insights, perceptions, and understanding enabled them to engage with clients, as well as manage risks and changes, assist key business processes and, importantly, deliver projects successfully. These skills contribute to the members’ individual professional development and capabilities. These might be termed Confidence, Relationships, Communication and Self-Management, Cooperation and Teamwork. Similarly, the research revealed the range of Know-How the members have developed. This range would include Understanding of Business Processes, Experimentation and Problem Solving, Reusing of Project Knowledge, Establishing and Marinating Quality, Project Time Estimates, and Learning from Project Failure the thesis also highlights the additional range of critical knowledge encapsulated within projects. This knowledge specifically related to Business Processes, Business Domains, Client and Working Environment. Such contextual implicit knowledge is part of the critical knowledge the practitioners acquired. Consequently, a model of successful practice within the unit was then built upon facets of this salient knowledge. An evaluation provided feedback on the system and assessed its suitability for the research unit. The unit members were satisfied with how the prototype restricted the key elements related to their knowledge and practice without duplicating information and acknowledged that it was the knowledge management system that best suits their needs. A focus group meeting with another similar software development unit highlighted and validated commonalities and differences in experience and in the nature of the individual organisations. The findings suggest that the proposed approach to recognising and utilising knowledge for transfer, reuse and consolidating effective practice is, potentially, extendable to similar domains. Continued research would explore the wider generalisability of this approach. Further research would explore extensions or revisions of the prototype that might further clarify the benefits and limitations of such an approach as well as providing a model for knowledge management in similar small-scale environments. This research might also serve as a template or road map for the implementation of KM initiatives elsewhere, such as start-up companies where there is a lack of software development expertise. Furthermore, the proposed system could serve as a model for the development of comparable systems in organisations where projects form the core of their work.
    • Terahertz Characterisation of Lead-Free Dielectrics for Different Applications

      Zhang, Man; Zhang, Hangfeng; Jiang, Qinghui; Gao, Feng; Chen, Riqing; Zhang, Dou; Reece, Michael J.; Yang, Bin; Viola, Giuseppe; Yan, Haixue; et al. (American Chemical Society, 2021-11-02)
      In this Spotlight on Applications, we describe our recent progress on the terahertz (THz) characterization of linear and non-linear dielectrics for broadening their applications in different electrical devices. We begin with a discussion on the behavior of dielectrics over a broadband of frequencies and describe the main characteristics of ferroelectrics, as an important category of non-linear dielectrics. We then move on to look at the influence of point defects, porosity and interfaces, including grain boundaries and domain walls, on the dielectric properties at THz frequencies. Based on our studies on linear dielectrics, we show that THz characterization is able to probe the effect of porosities, point defects, shear planes and grain boundaries to improve dielectric properties for telecommunication applications. Further, we demonstrate that THz measurements on relaxor ferroelectrics can be successfully used to study the reversibility of the electric field-induced phase transitions, providing guidance for improving their energy storage efficiency in capacitors. Finally, we show that THz characterization can be used to characterize the effect of domain walls in ferroelectrics. In particular, our studies indicate that the dipoles located within domain walls provide a lower contribution to the permittivity at THz frequencies than the dipoles present in domains. The new findings could help develop a new memory device based on non-destructive reading operations using a THz beam.
    • Terahertz probing of low temperature degradation in zirconia bioceramics

      Ahmed, Shafique; Zhang, Man; Koval, Vladimir; Zou, Lifong; Shen, Zhijian; Chen, Riqing; Yang, Bin; Yan, Haixue; Queen Mary University of London; Mehran University of Engineering and Technology; Institute of Materials Research; Stockholm University; Fujian Agriculture and Forestry University; University of Chester (Wiley, 2021-09-19)
      ZrO2 based ceramics are widely used in biomedical applications due to its colour, biocompatibility, and excellent mechanical properties. However, low temperature degradation (LTD) introduces a potential risk for long-term reliability of these materials. The development of innovative non-destructive techniques, which can explore LTD in zirconia-derived compounds, is strongly required. Yttria stabilised zirconia, 3Y-TZP, is one of the well-developed ZrO2 based ceramics with the improved resistance to LTD for dental crown and implant applications. Here, 3Y-TZP ceramic powders were pressed and sintered to study the LTD phenomenon by phase transition behaviour. The LTD driven tetragonal-to-monoclinic phase transition was confirmed by XRD. XPS analysis demonstrated the LTD induced the reduction of oxygen vacancies to support these findings. It is proved that after the degradation the 3Y-TZP ceramics show the decreased dielectric permittivity at terahertz frequencies due to the crystallographic phase transformation. Terahertz non-destructive probe is a promising method to investigate LTD in zirconia ceramics.
    • LevelEd SR: A Substitutional Reality Level Design Workflow

      Beever, Lee; John, Nigel W.; University of Chester
      Virtual reality (VR) and augmented reality (AR) have continued to increase in popularity over the past decade. However, there are still issues with how much space is required for room-scale VR and experiences are still lacking from haptic feedback. We present LevelEd SR, a substitutional reality level design workflow that combines AR and VR systems and is built for consumer devices. The system enables passive haptics through the inclusion of physical objects from within a space into a virtual world. A validation study (17 participants) has produced quantitative data that suggests players benefit from passive haptics in entertainment VR games with an improved game experience and increased levels of presence. Including objects, such as real-world furniture that is paired with a digital proxy in the virtual world, also opens up more spaces to be used for room-scale VR. We evaluated the workflow and found that participants were accepting of the system, rating it positively using the System Usability Scale questionnaire and would want to use it again to experience substitutional reality.
    • Application of Virtual Reality and Electrodermal Activity for the Detection of Cognitive Impairments

      Patient, Rebecca; Ghali, Fawaz; Kolivand, Hoshang; Hurst, William; John, Nigel W.; Liverpool John Moores; Wageningen University; University of Chester (IEEE, 2022-03-01)
      Mild Cognitive Impairment (MCI) is a definition of the diagnosis of early memory loss and disorientation. This study aims to identify people’s symptoms through technology. However, machine learning (ML) can classify Cognitive Normal (CN) and Mild Cognitive Impairment (MCI) and Early Mild Cognitive Impairment (EMCI) using standard assessments from the Alzheimer’s Disease Neuroimaging Initiative (ADNI); Montreal Cognitive (MoCA), Mini-Mental State Examination (MMSE), Functional Activities Questionnaire (FAQ). Consequently, a Multilayer Perceptron (MLP) model was assembled into tables; MCI vs CN, MCI vs EMCI, and CN vs MCI. Additionally, an MLP model was developed for CN vs MCI vs EMCI. As a result, of advanced model performance, a cascade 3-path categorisation approach was created. Similarly, the exploitation of meta-analysis indicated a combination of MLP models (MCI vs CN, MCI vs EMCI, and CN vs MCI) with an overall accuracy within an acceptable limit. In addition, better results were found when assessments were combined rather than individually. Furthermore, applying class weights and probability thresholds could improve the MLP framework by performance achieving a balanced specificity and sensitivity ratio. Altering class weights and probability thresholds when training the MLP neuro network model, the sensitivity and Accuracy could be progressed further. In conclusion, ML, VR and electrodermal activity are constrained. Introducing the possibility of activity-based applications to enhance innovative solutions for cognitive impairment diagnosis and treatment.