Elements: the design of an interactive virtual environment for movement rehabilitation of traumatic brain injury patients

This exegesis details the development of an interactive art work titled Elements designed to assist upper limb movement rehabilitation for patients recovering from traumatic brain injury. Enhancing physical rehabilitative processes in the early stages following a brain injury is one of the great challenges facing therapists. Elements enables physical user interaction that may present new opportunities for treatment. One of the key problems identified in the neuro-scientific field is that developers of interactive computer systems for movement rehabilitation are often constrained to the use of conventional desktop interfaces. These interfaces often fall short of fostering natural user interaction that translates into the relearning of body movement for patients, particularly in ways that reinforce the embodied relationship between the sensory world of the human body and the predictable effects of bodily movement in relation to the surrounding environment. Interactive multimedia environments that can correlate a patient’s sense of embodiment may assist in the acquisition of movement skills that transfer to the real world. The central theme of my exegesis will address these concerns by analysing contemporary theories of embodied interaction as a foundation to design Elements. Designing interactive computer environments for traumatic brain injured patients is, however, a challenging issue. Patients frequently exhibit impaired upper limb function which severely affects activities for daily living and self-care. Elements responds to this level of disability by providing the patient with an intuitive tabletop computer environment that affords basic gestural control. As part of a multidisciplinary project team, I designed the user interfaces, interactive multimedia environments, and audiovisual feedback (visual, haptic and auditory) used to help the patients relearn movement skills. The physical design of the Elements environment consists of a horizontal tabletop graphics display, a stereoscopic computer video tracking system, tangible user interfaces, and a suite of seven interactive software applications. Each application provides the patients with a task geared toward the patient reaching, grasping, lifting, moving, and placing the tangible user interfaces on the display. Audiovisual computer feedback is used by patients to refine their movements online and over time. Patients can manipulate the feedback to create unique aesthetic outcomes in real time. The system design provides tactility, texture, and audiovisual feedback to entice patients to explore their own movement capabilities in externally directed and self-directed ways. This exegesis contributes to the larger research agenda of embodied interaction. My original contribution to knowledge is Elements, an interactive artwork that may enable patients to relearn movement skills, raise their level of self-esteem, sense of achievement, and behavioural skill

Development of Immersive and Interactive Virtual Reality Environment for Two-Player Table Tennis

Although the history of Virtual Reality (VR) is only about half a century old, all kinds of technologies in the VR field are developing rapidly. VR is a computer generated simulation that replaces or augments the real world by various media. In a VR environment, participants have a perception of “presence”, which can be described by the sense of immersion and intuitive interaction. One of the major VR applications is in the field of sports, in which a life-like sports environment is simulated, and the body actions of players can be tracked and represented by using VR tracking and visualisation technology. In the entertainment field, exergaming that merges video game with physical exercise activities by employing tracking or even 3D display technology can be considered as a small scale VR. For the research presented in this thesis, a novel realistic real-time table tennis game combining immersive, interactive and competitive features is developed. The implemented system integrates the InterSense tracking system, SwissRanger 3D camera and a three-wall rear projection stereoscopic screen. The Intersense tracking system is based on ultrasonic and inertia sensing techniques which provide fast and accurate 6-DOF (i.e. six degrees of freedom) tracking information of four trackers. Two trackers are placed on the two players’ heads to provide the players’ viewing positions. The other two trackers are held by players as the racquets. The SwissRanger 3D camera is mounted on top of the screen to capture the player’

Nonlinear characterisation of power ultrasonic devices used in bone surgery

Ultrasonic cutting has existed in surgery since the 1950s. However, it was not until the end of the 20th century that advances in ultrasonic tool design, transduction and control allowed commercially viable ultrasonic cutting devices to enter the market. Ultrasonic surgical devices, like those in other power ultrasonic applications such as drilling and welding, require devices to be driven at high power to ensure sufficient output motion is produced to fulfil the application it is designed to perform. With the advent of novel surgical techniques surgeons require tuned ultrasonic tools which can reduce invasiveness while giving access to increasingly difficult to reach surgical sites. To fulfil the requirements of novel surgical procedures new tuned tools need to be designed. Meanwhile, it is well documented that power ultrasonic devices, whilst driven at high power, are inherently nonlinear and, if no attempt is made to understand and subsequently control these behaviours, it is likely that these devices will suffer from poor performance or even failure. The behaviour of the commercial ultrasonic transducer used in bone surgery (Piezosurgery® Device) is dynamically characterised through finite element and experimental methods whilst operating in conjunction with a variety of tuned inserts. Finite element analysis was used to predict modal parameters as well as stress levels within the tuned devices whilst operating at elevated amplitudes of vibration, while experimental modal analysis validated predicted resonant frequencies and mode shapes between 0-80kHz. To investigate the behaviour of tuned devices at elevated vibrational amplitudes near resonance, responses were measured whilst the device was excited via the burst sine sweep method. In an attempt to provide an understanding of the effects that geometry, material selection and wavelength of tuned assemblies have on the behaviour of an ultrasonic device, tuned inserts consisting of a simple rod horn design were characterised alongside more complex cutting inserts which are used in maxillofacial and craniofacial surgery. From these results the aim will be to develop guidelines for design of tuned inserts. Meanwhile, Langevin transducers, commonly known as sandwich or stack transducers, in their most basic form generally consist of four parts; a front mass, a back mass, a piezoceramic stack and a stud or bolt holding the parts together under a compressive pre-load. It is traditionally proposed that the piezoceramic stack is positioned at or close to the vibrational nodal point of the longitudinal mode, however, this also corresponds with the position of highest dynamic stress. It is also well documented that piezoceramic materials possess a low linear stress threshold, therefore this research, in part, investigates whether locating the piezoceramic stack away from a position of intrinsic high stress will affect the behaviour of the device. Through experimental characterisation it has been observed that the tuned devices under investigation exhibited; resonant frequency shifts, jump amplitudes, hysteretic behaviour as well as autoparametric vibration. The source of these behaviours have been found to stem from device geometry, but also from heating within the piezoceramic elements as well as joints with different joining torques

Laser-based manufacturing routes for functionalizing surfaces

Robust functional surfaces are of a growing industrial interest for a range of optical, easy-to clean, anti-icing and non-fouling applications. At the same time, nature is a great source of inspiration for micro/nano-scale surface structures with tailored functional properties. There are a number of competing technologies for producing such structures but ultrashort laser processing is emerging as one of the most promising for fabricating bio-inspired surfaces. However, the technology has limitations and its capabilities have to be augmented to achieve the required high throughput in manufacturing products that incorporate functional surface topographies. Therefore, this research investigates a promising process chain that combines synergistically the capabilities of laser texturing with complementary surface engineering and replication technologies. Several large-area laser texturing techniques are investigated, namely Direct Laser Writing (DLW), Laser-Induced Periodic Surface Structures (LIPSS) and microlenses-induced Photonic Jet (PJ) texturing. The research advances the knowledge in laser-based surface functionalization and also in factors affecting the functional response and durability of laser structured surfaces

Advancing nanofabrication processes for the generation of multifunctional surfaces

Ubiquitous in the natural world, micro- and/or nano-structured surfaces can afford simultaneous control over a range of interfacial properties; providing an attractive solution for where the accumulation of fluids (fog/rain/oil) and bacteria, and the mismanaged interaction of photons, can impede the safety or efficiency of the surface. Although surfaces found in nature provide a wealth of inspiration, replicating the structures synthetically persists to be a challenge, particularly so when striving for scalability and simplicity to encourage industrial/commercial uptake. Furthermore, the fabrication challenges become amplified when aiming for sub-wavelength structures; often necessary to unlock or enhance additional functionality. In this thesis, I present novel fabrication routes based on lithography and reactive ion etching (RIE) to achieve a range of ordered structures at the nano-scale in glass and silicon, and further replicate the resultant structures into polymers. I explore scalable masking techniques including block copolymer (BCP) lithography, laser interference lithography (LIL) and nanoimprint lithography (NIL), to achieve a series of pitches from 50 – 600 nm. By coupling the masking with novel combinations of etching chemistries, and taking advantage of the etch resistivity of different materials, I fabricate high aspect ratio nanostructures through simplified processes and demonstrate their ability to target applications in wettability, photonics and anti-bacterial action. Specifically, for silicon and glass nanocones, I focus on their anti-fogging, superhydrophobic, anti-reflective and anti-bacterial properties. I also investigate the impact of the nanostructure morphology on a sub-class of water-repellent surfaces, namely, slippery liquid infused porous surfaces, and their ability to retain lubricant under dynamic conditions; continuing on the theme of smart nanostructure design and simplified fabrication to pave a route to multifunctional surfaces. It is anticipated that the surfaces and their properties will find use as car windscreens, coatings for solar panels, high-rise glass facades, and high-touch surfaces to name a few

INTERACT 2015 Adjunct Proceedings. 15th IFIP TC.13 International Conference on Human-Computer Interaction 14-18 September 2015, Bamberg, Germany

INTERACT is among the world’s top conferences in Human-Computer Interaction. Starting with the first INTERACT conference in 1990, this conference series has been organised under the aegis of the Technical Committee 13 on Human-Computer Interaction of the UNESCO International Federation for Information Processing (IFIP). This committee aims at developing the science and technology of the interaction between humans and computing devices. The 15th IFIP TC.13 International Conference on Human-Computer Interaction - INTERACT 2015 took place from 14 to 18 September 2015 in Bamberg, Germany. The theme of INTERACT 2015 was "Connection.Tradition.Innovation". This volume presents the Adjunct Proceedings - it contains the position papers for the students of the Doctoral Consortium as well as the position papers of the participants of the various workshops

Investigation of Photon Interactions with Semiconductor Quantum Dot Devices for Quantum Communication Applications

A major goal in the field of quantum communication is to achieve long-distance (>100 km) transmission of quantum information, which would allow for the formation of a global quantum network. Devices called 'quantum repeaters' will enable delicate quantum states to be transmitted over long distances without succumbing to the signal losses inherent in the use of optical fibres. This thesis presents my work on a new type of hybrid quantum repeater design, which will combine both the photonic and spin qubit platforms to achieve more robust and efficient quantum communication. The focus of this work is on the optical aspects of this 'photon-to-spin' system, specifically the development of a method for delivering fibre-coupled single photons through an optical fibre to a lateral quantum dot device in a dilution refrigerator while preserving their polarisation states