879 resultados para 020603 Quantum Information Computation and Communication


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The future power grid will effectively utilize renewable energy resources and distributed generation to respond to energy demand while incorporating information technology and communication infrastructure for their optimum operation. This dissertation contributes to the development of real-time techniques, for wide-area monitoring and secure real-time control and operation of hybrid power systems. ^ To handle the increased level of real-time data exchange, this dissertation develops a supervisory control and data acquisition (SCADA) system that is equipped with a state estimation scheme from the real-time data. This system is verified on a specially developed laboratory-based test bed facility, as a hardware and software platform, to emulate the actual scenarios of a real hybrid power system with the highest level of similarities and capabilities to practical utility systems. It includes phasor measurements at hundreds of measurement points on the system. These measurements were obtained from especially developed laboratory based Phasor Measurement Unit (PMU) that is utilized in addition to existing commercially based PMU’s. The developed PMU was used in conjunction with the interconnected system along with the commercial PMU’s. The tested studies included a new technique for detecting the partially islanded micro grids in addition to several real-time techniques for synchronization and parameter identifications of hybrid systems. ^ Moreover, due to numerous integration of renewable energy resources through DC microgrids, this dissertation performs several practical cases for improvement of interoperability of such systems. Moreover, increased number of small and dispersed generating stations and their need to connect fast and properly into the AC grids, urged this work to explore the challenges that arise in synchronization of generators to the grid and through introduction of a Dynamic Brake system to improve the process of connecting distributed generators to the power grid.^ Real time operation and control requires data communication security. A research effort in this dissertation was developed based on Trusted Sensing Base (TSB) process for data communication security. The innovative TSB approach improves the security aspect of the power grid as a cyber-physical system. It is based on available GPS synchronization technology and provides protection against confidentiality attacks in critical power system infrastructures. ^

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Acknowledgements: This research was carried out through a grant from the EPSRC: Communities and Cultures Network+ EP/K003585 and forms part of the dot.rural Rural Digital Economy Research Hub EP/G066051

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Acknowledgements: This research was carried out through a grant from the EPSRC: Communities and Cultures Network+ EP/K003585 and forms part of the dot.rural Rural Digital Economy Research Hub EP/G066051

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Acknowledgements The research described here is supported by the award made by the RCUK Digital Economy programme to the dot.rural Digital Economy Research Hub; award reference: EP/G066051/1. Further, we would like to acknowledge the RCUK research grant EP/J000604/2.

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Quantitative Structure-Activity Relationship (QSAR) has been applied extensively in predicting toxicity of Disinfection By-Products (DBPs) in drinking water. Among many toxicological properties, acute and chronic toxicities of DBPs have been widely used in health risk assessment of DBPs. These toxicities are correlated with molecular properties, which are usually correlated with molecular descriptors. The primary goals of this thesis are: 1) to investigate the effects of molecular descriptors (e.g., chlorine number) on molecular properties such as energy of the lowest unoccupied molecular orbital (ELUMO) via QSAR modelling and analysis; 2) to validate the models by using internal and external cross-validation techniques; 3) to quantify the model uncertainties through Taylor and Monte Carlo Simulation. One of the very important ways to predict molecular properties such as ELUMO is using QSAR analysis. In this study, number of chlorine (NCl) and number of carbon (NC) as well as energy of the highest occupied molecular orbital (EHOMO) are used as molecular descriptors. There are typically three approaches used in QSAR model development: 1) Linear or Multi-linear Regression (MLR); 2) Partial Least Squares (PLS); and 3) Principle Component Regression (PCR). In QSAR analysis, a very critical step is model validation after QSAR models are established and before applying them to toxicity prediction. The DBPs to be studied include five chemical classes: chlorinated alkanes, alkenes, and aromatics. In addition, validated QSARs are developed to describe the toxicity of selected groups (i.e., chloro-alkane and aromatic compounds with a nitro- or cyano group) of DBP chemicals to three types of organisms (e.g., Fish, T. pyriformis, and P.pyosphoreum) based on experimental toxicity data from the literature. The results show that: 1) QSAR models to predict molecular property built by MLR, PLS or PCR can be used either to select valid data points or to eliminate outliers; 2) The Leave-One-Out Cross-Validation procedure by itself is not enough to give a reliable representation of the predictive ability of the QSAR models, however, Leave-Many-Out/K-fold cross-validation and external validation can be applied together to achieve more reliable results; 3) ELUMO are shown to correlate highly with the NCl for several classes of DBPs; and 4) According to uncertainty analysis using Taylor method, the uncertainty of QSAR models is contributed mostly from NCl for all DBP classes.

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In today’s technology-driven marketplace, the adoption and management of corporate and customer-facing Social Networking Sites (SNs) is often viewed as a key success factor for Travel Industry (TI) organisations. Knowledge management and the sharing of expertise and experiences through communication between internal and external stakeholders via social networks is an activity which TI organisations are aiming to exploit in order to improve the open sharing, retrieval, organisation and leveraging of knowledge. Through a study of currently-available literature relating to social networking adoption within the TI and a case study analysis of corporate social networking practices at three multi-national TI organisations (British Airways, Thomas Cook and Marriott Hotels), it may be observed that correlations exist between the development of social networking and the processes TI organisations now use to manage knowledge. We explore how these companies are currently utilizing SNs to improve knowledge management practices inside and outside of their organisational boundaries. From our analysis, lessons may emerge as to how TI companies are gaining competitive advantage through the use of social networking; a proposed strategy is identified to determine how TI organisations may make best use of social networks.

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The second theme of this book concerns L&D’s ‘Contributions’, specifically how L&D professionals articulate, communicate and demonstrate value that it brings to the organization. Specifically, Chapter 3, titled ‘Using information, metrics and developing business cases for L&D’, discusses how L&D professionals can do this using the business case as a vehicle. The business case is a tool that L&D professionals can use to show how new L&D initiatives can benefit the organization and its stakeholders. The value of such benefit can be ‘articulated’ quantitatively and qualitatively. Chapter 3 adopts a holistic approach in developing a business case. L&D professionals must be competently knowledgeable about accounting and finance but without the need to be experts – as their expertise lies in L&D. Therefore to successfully complete a business case, L&D professionals need to form teams comprising the right members (depending on what the business case is about). The political realities that are associated with the development of a business case can be important considerations. How well L&D is able to ‘sell’ a business case depends on how well it is framed, usually either as a problem or opportunity. We then discuss the information, data and metrics required to build a typical business case, specifically in terms of identifying the benefits and costs. The chapter concludes with some suggestions on how the findings from the business case can be presented in infographics-inspired form.

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It is now generally accepted that cyber crime represents a big threat to organisations, and that they need to take appropriate action to protect their valuable information assets. However, current research shows that, although small businesses understand that they are potentially vulnerable, many are still not taking sufficient action to counteract the threat. Last year, the authors sought, through a more generalised but categorised attitudinal study, to explore the reasons why smaller SMEs in particular were reluctant to engage with accepted principles for protecting their data. The results showed that SMEs understood many of the issues. They were prepared to spend more but were particularly suspicious about spending on information assurance. The authors’ current research again focuses on SME attitudes but this time the survey asks only questions directly relating to information assurance and the standards available, in an attempt to try to understand exactly what is causing them to shy away from getting the badge or certificate that would demonstrate to customers and business partners that they take cyber security seriously. As with last year’s study, the results and analysis provide useful pointers towards the broader business environment changes that might cause SMEs to be more interested in working towards an appropriate cyber security standard.

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Published in Electronic Handling of Information: Testing and Evaluation, Kent, Taubee, Beltzer, and Goldstein (ed.), Academic Press, London(1967), pp. 123–147.

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Urban wayfinding technology offers many possibilities by which older people and mobility-impaired users can overcome the barriers encountered on every-day journeys in the built environment. Previous work has highlighted the extent to which personal mobility and independence are significant determinants of the quality of life amongst both elderly and visually impaired groups. The paper outlines the development of the auditory location finder (ALF), which is a beacon-based local information system designed to enhance the wayfinding activities of these, and potentially other, user-groups in the community. The proposed system provides the user with an audio message, which is obtained on request via a small portable hand unit. The messages inform the user of their whereabouts and give information about the area that they are currently in. The development of the device involves issues such as message content and structure, route choice, orientation, landmarks, clues and the extent of user reliance on technology. Preliminary trials have been carried out in a UK city and have obtained initial user feedback to help underpin the technological development of the device and its potential application. The paper concludes by outlining the importance of new urban technology and the way in which such local information systems can potentially contribute to overcoming particular patterns of exclusion experienced by mobility-impaired groups, such as the visually impaired

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A natural way to generalize tensor network variational classes to quantum field systems is via a continuous tensor contraction. This approach is first illustrated for the class of quantum field states known as continuous matrix-product states (cMPS). As a simple example of the path-integral representation we show that the state of a dynamically evolving quantum field admits a natural representation as a cMPS. A completeness argument is also provided that shows that all states in Fock space admit a cMPS representation when the number of variational parameters tends to infinity. Beyond this, we obtain a well-behaved field limit of projected entangled-pair states (PEPS) in two dimensions that provide an abstract class of quantum field states with natural symmetries. We demonstrate how symmetries of the physical field state are encoded within the dynamics of an auxiliary field system of one dimension less. In particular, the imposition of Euclidean symmetries on the physical system requires that the auxiliary system involved in the class' definition must be Lorentz-invariant. The physical field states automatically inherit entropy area laws from the PEPS class, and are fully described by the dissipative dynamics of a lower dimensional virtual field system. Our results lie at the intersection many-body physics, quantum field theory and quantum information theory, and facilitate future exchanges of ideas and insights between these disciplines.