Transiently Powered Computers

Demand for compact, easily deployable, energy-efficient computers has driven the development of general-purpose transiently powered computers (TPCs) that lack both batteries and wired power, operating exclusively on energy harvested from their surroundings. TPCs\u27 dependence solely on transient, harvested power offers several important design-time benefits. For example, omitting batteries saves board space and weight while obviating the need to make devices physically accessible for maintenance. However, transient power may provide an unpredictable supply of energy that makes operation difficult. A predictable energy supply is a key abstraction underlying most electronic designs. TPCs discard this abstraction in favor of opportunistic computation that takes advantage of available resources. A crucial question is how should a software-controlled computing device operate if it depends completely on external entities for power and other resources? The question poses challenges for computation, communication, storage, and other aspects of TPC design. The main idea of this work is that software techniques can make energy harvesting a practicable form of power supply for electronic devices. Its overarching goal is to facilitate the design and operation of usable TPCs. This thesis poses a set of challenges that are fundamental to TPCs, then pairs these challenges with approaches that use software techniques to address them. To address the challenge of computing steadily on harvested power, it describes Mementos, an energy-aware state-checkpointing system for TPCs. To address the dependence of opportunistic RF-harvesting TPCs on potentially untrustworthy RFID readers, it describes CCCP, a protocol and system for safely outsourcing data storage to RFID readers that may attempt to tamper with data. Additionally, it describes a simulator that facilitates experimentation with the TPC model, and a prototype computational RFID that implements the TPC model. To show that TPCs can improve existing electronic devices, this thesis describes applications of TPCs to implantable medical devices (IMDs), a challenging design space in which some battery-constrained devices completely lack protection against radio-based attacks. TPCs can provide security and privacy benefits to IMDs by, for instance, cryptographically authenticating other devices that want to communicate with the IMD before allowing the IMD to use any of its battery power. This thesis describes a simplified IMD that lacks its own radio, saving precious battery energy and therefore size. The simplified IMD instead depends on an RFID-scale TPC for all of its communication functions. TPCs are a natural area of exploration for future electronic design, given the parallel trends of energy harvesting and miniaturization. This work aims to establish and evaluate basic principles by which TPCs can operate

Experimental Evaluation of Growing and Pruning Hyper Basis Function Neural Networks Trained with Extended Information Filter

In this paper we test Extended Information Filter (EIF) for sequential training of Hyper Basis Function Neural Networks with growing and pruning ability (HBF-GP). The HBF neuron allows different scaling of input dimensions to provide better generalization property when dealing with complex nonlinear problems in engineering practice. The main intuition behind HBF is in generalization of Gaussian type of neuron that applies Mahalanobis-like distance as a distance metrics between input training sample and prototype vector. We exploit concept of neuron’s significance and allow growing and pruning of HBF neurons during sequential learning process. From engineer’s perspective, EIF is attractive for training of neural networks because it allows a designer to have scarce initial knowledge of the system/problem. Extensive experimental study shows that HBF neural network trained with EIF achieves same prediction error and compactness of network topology when compared to EKF, but without the need to know initial state uncertainty, which is its main advantage over EKF

Degrees of virtue :inculcating a professional academic habitus in the field of post 1992 higher education

This study aims to contribute original knowledge of the identity ofpost-1992 academics to inform the debate surrounding the professionalization of higher education teachers. The setting was a modem university in the East Midlands. Bourdieusian theoretical conceptualizations of the mediated relations between agency and structure (habitus/field theory) were applied to deconstruct/reconstruct the nature of these relations within the university's academic workforce. This investigation revealed disjunctions amongst staff members. The study's findings suggest that these might be addressed through structured training in the logic of practice for recruits. Bourdieu [1930-2002] developed a mixed methods methodology, combining positivist and phenomenological research paradigms to ensure breadth and depth in ethical data interrogations. This approach informed the sequential mixed design of the study. The first phase (survey) elicited profile and benchmarking data and perceptions of field forces and conditions from sixty respondents. Most lacked teaching qualifications or experience on entry. The second phase (fifteen interviews) captured personal narratives for subsequent thematic analysis. Current evaluation of primary data indicates three significant trajectories analyses: effective actionlbehaviour arising from the meaningful convergence of the individual's competences (mapped as habitus), the organizational environment (field) and the job's demands (practice). Data filtration through these lenses uncovered destabilizing divergences. Significantly, most participants eschewed identification as an 'academic'; seeing themselves as first and foremost a teacher. Their key concerns were negative perceptions of management and student demands as threats to personal efficacy, thus an accredited teacher training programme instilling a dual professionalism was broadly welcomed. This study provides timely sociological perspectives on the government's recent positive correlation between funding and new staff accreditation. Institutional reliance upon existing and contract staff, however, suggests their training needs warrant further investigation. This thesis argues for such training to make explicit the science of pedagogy and the art of teaching to all teaching staff through the conscious integration of habitus/field theory in higher education teacher training. In this way, both agent and field are strengthened, to their mutual advantage.EThOS - Electronic Theses Online ServiceGBUnited Kingdo