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We introduce a technique that allows the topology of a Network-on-Chip (NoC) to reconfigure continuously at runtime. Existing approaches have permitted reconfiguration between execu- tions of statically analysed applications. Starting from a regular mesh topology, our technique allows the network to adapt to a traffic pattern in order to reduce router activity and the average hop count of packets. We apply the concept of emergence so that macro-scale topology reconfig- , urations emerge as a consequence of repeatedly applying micro-scale rules at individual nodes. Our method utilises simple distributed single-hop message passing. This allows the technique to scale to arbitrary size networks with no extra logic cost or increased latency in reconfiguration. This is inspired by emergent goal-oriented networks, where global optimisations are produced by micro-scale reconfigurations. We believe that emergent processes are an efficient and scalable method of managing in- terconnect resources in large parallel systems. We present an architecture that reorganises the logical structure of the network as an example of the global optimisations that can be achieved using emergence. Each node of the network acts independently, applying a set of micro-rules that perform an analysis of local traffic to choose when to place or remove a local topology micro-reconfiguration known as a Skip-link. A set of placement rules limit the extent to which the topology may be deformed and are enforced by relaying topology changes to directly adjacent nodes, The bandwidth used by these communications is negligible. A new routing algorithm, Topology Adaptive Routing (TAR), is presented, In addition, asynchronous circuits to ensure packet ordering and synchronisation when placing a Skip-link are described, The system is evaluated using software simulation and a range of traffic types. Traditional permutation traffic is used to establish worst-case performance and a mono-fractal traffic synthesis model is used to generate traffic that resembles that of real applications. We compare the performance of a Skip-link enabled network with a standard mesh using Dimension Order Routing (DOR) and show that latency and energy reductions can be achieved over a static topology. The relationship between reduced average hop-count and critical load is investigated. In networks of up to 256 nodes, we achieve logical hop savings of up to 18% and critical load improvements of up to 33%. Per-flit energy savings of around 10% are also achieved. We also demonstrate that hop reductions increase with the size of the network.

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The existing approaches to ruggedizing inherently fragile and sensitive critical components of electronic equipment such as printed circuit boards (PCB) for use in hostile industrial and military environment are either insufficient or quite expensive. This Thesis addresses a novel approach towards ruggedizing commercially-off-the-shelf PCBs using a miniature wide-band dynamic absorber aimed at essential suppressing of the resonant responses of the original structure. The development of an optimisation technique is based on the dynamic properties of the original system, where the mass, stiffness and damping properties of the dynamic absorber are chosen in such a fashion to minimise the level of vibration experienced by the system. The optimisation procedure relies on the analytical solution and computational resources. The results of the proposed single-mode and full-mode approximation are proven experimentally under random vibration. Further study of the dynamic absorber is achieved by considering the system under swept-sine and shock excitations. This approach eventually focuses on the universal performance of the optimal dynamic absorber.

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Traditionally electron beam lithography (EBL) has been used to fabricate micron and sub-micron sized devices, such as Γ and Τ gates for metal-semiconductor devices for study within the semiconductor industry. EBL is also used for the fabrication of ferromagnetic elements for use as components in magnetic random access memory (MRAM) and read/write heads in hard disk drives (HDD). MRAM is being investigated as a direct replacement to standard semiconductor RAM as it has lower power consumption and is a non-volatile memory solution, although the areal density, at present, is not as great. Smaller read/write heads are necessary for HDD as recent advances now allow for perpendicular magnetisation (as opposed to parallel magnetisation) of films and increase the areal density to 100 Gb/inch2, four times the current value. In this thesis, the physical and magnetic properties of such micron-sized devices that have been fabricated by focussed ion beam (FIB) lithography for comparison to those fabricated by the EBL method are discussed. In addition to this work, the physical and magnetic properties of micron-sized element that have been irradiated using the 30 keV gallium ion source are also discussed. Also in this thesis, the results of 10×10 μm2 arrays of 50 nm thick polycrystalline cobalt elements (270×270 nm2 with a 400 nm period) that are fabricated by EBL to determine if there is any magnetic superdomain structure present are discussed. Bright field imaging in a transmission electron microscope (TEM) is used to investigate the physical structure of the ferromagnets, such as the grain size, element roughness and dimensions. Additional information about the topography is measured by atomic force microscopy (AFM). The magnetic properties, such as the magnitude of the applied field at which irreversible events happen and the domain structure, are investigated by the Fresnel imaging and the differential phase contrast modes of Lorentz microscopy. A programme known as object orientated micromagnetic framework (OOMMF) is used to model the magnetic properties of such structures.