• Evolutionary Robot Swarm Cooperative Retrieval

      Vaughan, Neil; Royal Academy of Engineering; University of Chester (Springer, 2018-07-07)
      In nature bees and leaf-cutter ants communicate to improve cooperation during food retrieval. This research aims to model communication in a swarm of auton-omous robots. When food is identified robot communication is emitted within a limited range. Other robots within the range receive the communication and learn of the location and size of the food source. The simulation revealed that commu-nication improved the rate of cooperative food retrieval tasks. However a counter-productive chain reaction can occur when robots repeat communications from other robots causing cooperation errors. This can lead to a large number of robots travelling towards the same food source at the same time. The food becomes de-pleted, before some robots have arrived. Several robots continue to communicate food presence, before arriving at the food source to find it gone. Nature-inspired communication can enhance swarm behaviour without requiring a central control-ler and may be useful in autonomous drones or vehicles.
    • Formal Verification of Astronaut-Rover Teams for Planetary Surface Operations

      Webster, Matt; Dennis, Louise A; Dixon, Clare; Fisher, Michael; Stocker, Richard; Sierhuis, Maarten; University of Liverpool; University of Chester; Ejenta, inc.
      This paper describes an approach to assuring the reliability of autonomous systems for Astronaut-Rover (ASRO) teams using the formal verification of models in the Brahms multi-agent modelling language. Planetary surface rovers have proven essential to several manned and unmanned missions to the moon and Mars. The first rovers were tele- or manuallyoperated, but autonomous systems are increasingly being used to increase the effectiveness and range of rover operations on missions such as the NASA Mars Science Laboratory. It is anticipated that future manned missions to the moon and Mars will use autonomous rovers to assist astronauts during extravehicular activity (EVA), including science, technical and construction operations. These ASRO teams have the potential to significantly increase the safety and efficiency of surface operations. We describe a new Brahms model in which an autonomous rover may perform several different activities including assisting an astronaut during EVA. These activities compete for the autonomous rovers “attention’ and therefore the rover must decide which activity is currently the most important and engage in that activity. The Brahms model also includes an astronaut agent, which models an astronauts predicted behaviour during an EVA. The rover must also respond to the astronauts activities. We show how this Brahms model can be simulated using the Brahms integrated development environment. The model can then also be formally verified with respect to system requirements using the SPIN model checker, through automatic translation from Brahms to PROMELA (the input language for SPIN). We show that such formal verification can be used to determine that mission- and safety critical operations are conducted correctly, and therefore increase the reliability of autonomous systems for planetary rovers in ASRO teams.
    • Haptic feedback from human tissues of various stiffness and homogeneity.

      Vaughan, Neil; Dubey, Venketesh N.; Wee, Michael Y. K.; Isaacs, Richard; Bournemouth University; Poole Hospital NHS Foundation Trust (Techno-Press, 2014-07-01)
      This work presents methods for haptic modelling of soft and hard tissue with varying stiffness. The model provides visualization of deformation and calculates force feedback during simulated epidural needle insertion. A spring-mass-damper (SMD) network is configured from magnetic resonance image (MRI) slices of patient’s lumbar region to represent varying stiffness throughout tissue structure. Reaction force is calculated from the SMD network and a haptic device is configured to produce a needle insertion simulation. The user can feel the changing forces as the needle is inserted through tissue layers and ligaments. Methods for calculating the force feedback at various depths of needle insertion are presented. Voxelization is used to fill ligament surface meshes with spring mass damper assemblies for simulated needle insertion into soft and hard tissues. Modelled vertebrae cannot be pierced by the needle. Graphs were produced during simulated needle insertions to compare the applied force to haptic reaction force. Preliminary saline pressure measurements during Tuohy epidural needle insertion are also used as a basis for forces generated in the simulation.
    • How effective is Ant Colony Optimisation at Robot Path Planning

      Wolfenden, A.; Vaughan, Neil; University of Chester (The Society for the Study of Artificial Intelligence and Simulation for Behaviour (AISB), 2018-04-06)
      This project involves investigation of the problem robot path planning using ant colony optimisation heuristics to construct the quickest path from the starting point to the end. The project has developed a simulation that successfully simulates as well as demonstrates visually through a graphical user interface, robot path planning using ant colony optimisation. The simulation shows an ability to traverse an unknown environment from a start point to an end and successfully construct a route for others to follow both when the terrain is dynamic and static
    • The Implementation and Validation of a Virtual Environment for Training Powered Wheelchair Manoeuvres

      John, Nigel W.; Pop, Serban R.; Day, Thomas W.; Ritsos, Panagiotis D.; Headleand, Christopher J.; University of Chester; Bangor University; University of Lincoln (IEEE, 2017-05-02)
      Navigating a powered wheelchair and avoiding collisions is often a daunting task for new wheelchair users. It takes time and practice to gain the coordination needed to become a competent driver and this can be even more of a challenge for someone with a disability. We present a cost-effective virtual reality (VR) application that takes advantage of consumer level VR hardware. The system can be easily deployed in an assessment centre or for home use, and does not depend on a specialized high-end virtual environment such as a Powerwall or CAVE. This paper reviews previous work that has used virtual environments technology for training tasks, particularly wheelchair simulation. We then describe the implementation of our own system and the first validation study carried out using thirty three able bodied volunteers. The study results indicate that at a significance level of 5% then there is an improvement in driving skills from the use of our VR system. We thus have the potential to develop the competency of a wheelchair user whilst avoiding the risks inherent to training in the real world. However, the occurrence of cybersickness is a particular problem in this application that will need to be addressed.
    • In vitro and Computational Modelling of Drug Delivery across the Outer Blood-Retinal Barrier

      Davies, Alys E; Williams, Rachel L.; Lugano, Gaia; Pop, Serban R.; Kearns, Victoria R.; University of Liverpool; University of Chester
      The ability to produce rapid, cost-effective and human-relevant data has the potential to accelerate development of new drug delivery systems. Intraocular drug delivery is an area undergoing rapid expansion due to the increase in sight-threatening diseases linked to increasing age and lifestyle factors. The outer bloodretinal barrier (OBRB) is important in this area of drug delivery, as it separates the eye from the systemic blood flow. This study reports the development of complementary in vitro and in silico models to study drug transport from silicone oil across the outer blood-retinal barrier. Monolayer cultures of a human retinal pigmented epithelium cell line, ARPE-19, were added to chambers and exposed to a controlled flow to simulate drug clearance across the OBRB. Movement of dextran molecules and release of ibuprofen from silicone oil in this model were measured. Corresponding simulations were developed using COMSOL Multiphysics computational fluid dynamics (CFD) software and validated using independent in vitro data sets. Computational simulations were able to predict dextran movement and ibuprofen release, with all of the features of the experimental release profiles being observed in the simulated data. Simulated values for peak concentrations of permeated dextran and ibuprofen released from silicone oil were within 18% of the in vitro results. This model could be used as a predictive tool of drug transport across this important tissue.
    • An Information-Theoretic Approach to the Cost-benefit Analysis of Visualization in Virtual Environments

      Chen, Min; Gaither, Kelly; John, Nigel W.; McCann, Brian; University of Oxford; University of Texas at Austin; University of Chester (IEEE, 2018-08-20)
      Visualization and virtual environments (VEs) have been two interconnected parallel strands in visual computing for decades. Some VEs have been purposely developed for visualization applications, while many visualization applications are exemplary showcases in general-purpose VEs. Because of the development and operation costs of VEs, the majority of visualization applications in practice have yet to benefit from the capacity of VEs. In this paper, we examine this status quo from an information-theoretic perspective. Our objectives are to conduct cost-benefit analysis on typical VE systems (including augmented and mixed reality, theatre-based systems, and large powerwalls), to explain why some visualization applications benefit more from VEs than others, and to sketch out pathways for the future development of visualization applications in VEs. We support our theoretical propositions and analysis using theories and discoveries in the literature of cognitive sciences and the practical evidence reported in the literatures of visualization and VEs.
    • Interventional radiology virtual simulator for liver biopsy

      Villard, Pierre-Frédéric; Vidal, Franck P.; ap Cenydd, Llyr; Holbrey, Richard; Pisharody, S.; Johnson, Sheena; Bulpitt, Andy; John, Nigel W.; Bello, Fernando; Gould, Daniel (Springer, 2013-07-24)
      Training in Interventional Radiology currently uses the apprenticeship model, where clinical and technical skills of invasive procedures are learnt during practice in patients. This apprenticeship training method is increasingly limited by regulatory restrictions on working hours, concerns over patient risk through trainees' inexperience and the variable exposure to case mix and emergencies during training. To address this, we have developed a computer-based simulation of visceral needle puncture procedures. Methods A real-time framework has been built that includes: segmentation, physically based modelling, haptics rendering, pseudo-ultrasound generation and the concept of a physical mannequin. It is the result of a close collaboration between different universities, involving computer scientists, clinicians, clinical engineers and occupational psychologists. Results The technical implementation of the framework is a robust and real-time simulation environment combining a physical platform and an immersive computerized virtual environment. The face, content and construct validation have been previously assessed, showing the reliability and effectiveness of this framework, as well as its potential for teaching visceral needle puncture. Conclusion A simulator for ultrasound-guided liver biopsy has been developed. It includes functionalities and metrics extracted from cognitive task analysis. This framework can be useful during training, particularly given the known difficulties in gaining significant practice of core skills in patients.
    • Island Coalescence during Film Growth: An Underestimated Limitation of Cu ALD

      Hagen, Dirk J.; Connolly, James; Povey, Ian M.; Rushworth, Simon; Pemble, Martyn E. (Wiley, 2017-05-31)
    • Jazz on the border: Jazz and dance bands in Chester and North Wales in mid-twentieth century

      Southall, Helen; University of Chester (Equinox, 2013)
      There was a high degree of overlap between western popular music and jazz in the mid- twentieth century. However, histories of jazz and histories of popular music are often puzzlingly separate, as if divided by strict borders. This article looks at some of the rea- sons for this (including those proposed by Frith (2007) and Bennett (2013). The impor- tance of musical pathways and hidden histories (Becker 2002, 2004; Finnegan 2007; Nott 2002; Rogers 2013) in the context of local music scenes is considered. The importance of taking live music scenes and provincial areas into account when discussing genre his- tories is discussed, in the context of examples from an oral history study of dance-band musicians and promoters in the Chester (UK) area. These examples help to demonstrate that boundaries between jazz and popular music are frequently less abrupt in practice than they are in theory.
    • Learning to combine multiple string similarity metrics for effective toponym matching

      Santos, Rui; Murrieta-Flores, Patricia; Martins, Bruno (Informa UK Limited, 2017-09-06)
    • LevelEd VR: A virtual reality level editor and workflow for virtual reality level design

      Beever, Lee; Pop, Serban W.; John, Nigel W.; University of Chester
      Virtual reality entertainment and serious games popularity has continued to rise but the processes for level design for VR games has not been adequately researched. Our paper contributes LevelEd VR; a generic runtime virtual reality level editor that supports the level design workflow used by developers and can potentially support user generated content. We evaluated our LevelEd VR application and compared it to an existing workflow of Unity on a desktop. Our current research indicates that users are accepting of such a system, and it has the potential to be preferred over existing workflows for VR level design. We found that the primary benefit of our system is an improved sense of scale and perspective when creating the geometry and implementing gameplay. The paper also contributes some best practices and lessons learned from creating a complex virtual reality tool, such as LevelEd VR.
    • LiTu - A Human-Computer Interface based on Frustrated Internal Reflection of Light

      Edwards, Marc R.; John, Nigel W.; University of Chester (IEEE Conference Publications, 2015-10)
      We have designed LiTu (Laɪ’Tu - Light Tube) as a customisable and low-cost (ca 30 Euros) human-computer interface. It is composed of an acrylic tube, a ball-bearing mirror, six LEDs and a webcam. Touching the tube causes frustrated internal reflection of light due to a change in the critical angle at the acrylic-skin boundary. Scattered light within the tube is reflected off the mirror into the camera at the opposite end for image processing. Illuminated contact regions in the video frames are segmented and processed to generate 2D information such as: pitch and volume, or x and y coordinates of a graphic. We demonstrate the functionality of LiTu both as a musical instrument and as an interactive computer graphics controller. For example, various musical notes can be generated by touching specific regions around the surface of the tube. Volume can be controlled by sliding a finger down the tube and pitch by sliding the finger radially. We demonstrate the adaptable nature of LiTu’s touch interface and discuss our plans to explore future physical modifications of the device.
    • Mobile technology-enhanced asset maintenance in an SME

      Bankosz, Grzegorz S.; Kerins, John; University of Chester (Emerald, 2014-05-06)
      This article discusses the development of a prototype system to demonstrate the potential benefits of deploying mobile technology to enhance asset maintenance processes in a small food manufacturing plant.
    • Modelling the effects of glucagon during glucose tolerance testing

      Kelly, Ross A; Fitches, Molly J; Webb, Steven D; Pop, Serban R; Chidlow, Stewart J; Liverpool John Moores University; University of Dundee; University of Chester
      Background Glucose tolerance testing is a tool used to estimate glucose effectiveness and insulin sensitivity in diabetic patients. The importance of such tests has prompted the development and utilisation of mathematical models that describe glucose kinetics as a function of insulin activity. The hormone glucagon, also plays a fundamental role in systemic plasma glucose regulation and is secreted reciprocally to insulin, stimulating catabolic glucose utilisation. However, regulation of glucagon secretion by α-cells is impaired in type-1 and type-2 diabetes through pancreatic islet dysfunction. Despite this, inclusion of glucagon activity when modelling the glucose kinetics during glucose tolerance testing is often overlooked. This study presents two mathematical models of a glucose tolerance test that incorporate glucose-insulin-glucagon dynamics. The first model describes a non-linear relationship between glucagon and glucose, whereas the second model assumes a linear relationship. Results Both models are validated against insulin-modified and glucose infusion intravenous glucose tolerance test (IVGTT) data, as well as insulin infusion data, and are capable of estimating patient glucose effectiveness (sG) and insulin sensitivity (sI). Inclusion of glucagon dynamics proves to provide a more detailed representation of the metabolic portrait, enabling estimation of two new diagnostic parameters: glucagon effectiveness (sE) and glucagon sensitivity (δ). Conclusions The models are used to investigate how different degrees of patient glucagon sensitivity and effectiveness affect the concentration of blood glucose and plasma glucagon during IVGTT and insulin infusion tests, providing a platform from which the role of glucagon dynamics during a glucose tolerance test may be investigated and predicted.
    • Morphogenetic Engineering For Evolving Ant Colony Pheromone Communication

      Vaughan, Neil; University of Chester (The Society for the Study of Artificial Intelligence and Simulation for Behaviour (AISB), 2018-04-06)
      This research investigates methods for evolving swarm communication in a simulated colony of ants using pheromone when foriaging for food. This research implemented neuroevolution and obtained the capability to learn pheromone communication autonomously. Building on previous literature on pheromone communication, this research applies evolution to adjust the topology and weights of an artificial neural network which controls the ant behaviour. Comparison of performance is made between a hard-coded benchmark algorithm, a fixed topology ANN and neuroevolution of the ANN topology and weights. The resulting neuroevolution produced a neural network which was successfully evolved to achieve the task objective, to collect food and return it to the nest.
    • Multi-Agent Reinforcement Learning for Swarm Retrieval with Evolving Neural Network

      Vaughan, Neil; Royal Academy of Engineering; University of Chester (Springer-Verlag,, 2018-07-07)
      This research investigates methods for evolving swarm communica-tion in a sim-ulated colony of ants using pheromone when foriaging for food. This research implemented neuroevolution and obtained the capability to learn phero-mone communication autonomously. Building on previous literature on phero-mone communication, this research applies evolution to adjust the topology and weights of an artificial neural network (ANN) which controls the ant behaviour. Compar-ison of performance is made between a hard-coded benchmark algorithm (BM1), a fixed topology ANN and neuroevolution of the ANN topology and weights. The resulting neuroevolution produced a neural network which was suc-cessfully evolved to achieve the task objective, to collect food and return it to a location.
    • An overview of self-adaptive technologies within virtual reality training

      Vaughan, Neil; Gabrys, Bogdan; Dubey, Venketesh; University of Chester
      This overview presents the current state-of-the-art of self-adaptive technologies within virtual reality (VR) training. Virtual reality training and assessment is increasingly used for five key areas: medical, industrial & commercial training, serious games, rehabilitation and remote training such as Massive Open Online Courses (MOOCs). Adaptation can be applied to five core technologies of VR including haptic devices, stereo graphics, adaptive content, assessment and autonomous agents. Automation of VR training can contribute to automation of actual procedures including remote and robotic assisted surgery which reduces injury and improves accuracy of the procedure. Automated haptic interaction can enable tele-presence and virtual artefact tactile interaction from either remote or simulated environments. Automation, machine learning and data driven features play an important role in providing trainee-specific individual adaptive training content. Data from trainee assessment can form an input to autonomous systems for customised training and automated difficulty levels to match individual requirements. Self-adaptive technology has been developed previously within individual technologies of VR training. One of the conclusions of this research is that while it does not exist, an enhanced portable framework is needed and it would be beneficial to combine automation of core technologies, producing a reusable automation framework for VR training.
    • An overview of thermal necrosis: present and future

      Mediouni, M.; Kucklick, T.; Poncet, S.; Madiouni, R.; Abouaomar, A.; Madry, H.; Cucchiarini, M.; Chopko, B.; Vaughan, Neil; Arora, M.; et al. (Taylor & Francis, 2019-05-10)
      Introduction: Many orthopaedic procedures require drilling of bone, especially fracture repair cases. Bone drilling results in heat generation due to the friction between the bone and the drill bit. A high-level of heat generation kills bone cells. Bone cell death results in resorption of bone around bone screws. Materials and methods: We searched in the literature for data on parameters that influence drilling bone and could lead to thermal necrosis. The points of view of many orthopaedists and neurosurgeons based upon on previous practices and clinical experience are presented. Results: Several potential complications are discussed and highlighted that lead to thermal necrosis. Discussion: Even in the face of growing evidence as to the negative effects of heat-induction during drilling, simple and effective methods for monitoring and cooling in real-time are not in widespread usage today. For that purpose, we propose some suggestions for the future of bone drilling, taking note of recent advances in autonomous robotics, intelligent systems, and computer simulation techniques. Conclusions: These advances in prevention of thermal necrosis during bone drilling surgery are expected to reduce the risk of patient injury and costs for the health service.
    • Parametric model of human body shape and ligaments for patient-specific epidural simulation

      Vaughan, Neil; Dubey, Venketesh N.; Wee, Michael Y. K.; Isaacs, Richard; Bournemouth University; Poole Hospital NHS Foundation Trust (Elsevier, 2014-09-04)
      Objective: This work builds upon the concept of matching a person’s weight, height and age to their overall body shape to create an adjustable three-dimensional model. A versatile and accurate predictor of body size and shape and ligament thickness is required to improve simulation for medical procedures. A model which is adjustable for any size, shape, body mass, age or height would provide ability to simulate procedures on patients of various body compositions. Methods: Three methods are provided for estimating body circumferences and ligament thicknesses for each patient. The first method is using empirical relations from body shape and size. The second method is to load a dataset from a magnetic resonance imaging scan (MRI) or ultrasound scan containing accurate ligament measurements. The third method is a developed artificial neural network (ANN) which uses MRI dataset as a training set and improves accuracy using error back-propagation, which learns to increase accuracy as more patient data is added. The ANN is trained and tested with clinical data from 23088 patients. Results: The ANN can predict subscapular skinfold thickness within 3.54mm, waist circumference 3.92cm, thigh circumference 2.00cm, arm circumference 1.21cm, calf circumference 1.40cm, triceps skinfold thickness 3.43mm. Alternative regression analysis method gave overall slightly less accurate predictions for subscapular skinfold thickness within 3.75mm, waist circumference 3.84cm, thigh circumference 2.16cm, arm circumference 1.34cm, calf circumference 1.46cm, triceps skinfold thickness 3.89mm. These calculations are used to display a 3D graphics model of the patient’s body shape using OpenGL and adjusted by 3D mesh deformations. Conclusions: A patient-specific epidural simulator is presented using the developed body shape model, able to simulate needle insertion procedures on a 3D model of any patient size and shape. The developed ANN gave the most accurate results for body shape, size and ligament thickness. The resulting simulator offers the experience of simulating needle insertions accurately whilst allowing for variation in patient body mass, height or age.