2,072 research outputs found

    Chern-Simons Diffusion Rate near the Electroweak Phase Transition for mHmWm_H \approx m_W

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    The rate of BB-violation in the standard model at finite temperature is closely related to the diffusion rate Γ\Gamma of Chern-Simons number. We compute this rate for mHmWm_H \approx m_W in the classical approximation in an effective SU(2)-Higgs model, using Krasnitz's algorithm. The parameters in the effective hamiltonian are determined by comparison with dimensional reduction. In the high temperature phase we find Γ/V(αWT)41\Gamma/V (\alpha_W T)^4 \approx 1, neglecting a finite renormalization. In the low temperature phase near the transition we find the rate to be much larger than might be expected from previous analytic calculations based on the sphaleron.Comment: 23 pages, 8 Postscript figures, uses epsf.st

    Geometric Aspects of Frame Representations of Abelian Groups

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    We consider frames arising from the action of a unitary representation of a discrete countable abelian group. We show that the range of the analysis operator can be determined by computing which characters appear in the representation. This allows one to compare the ranges of two such frames, which is useful for determining similarity and also for multiplexing schemes. Our results then partially extend to Bessel sequences arising from the action of the group. We apply the results to sampling on bandlimited functions and to wavelet and Weyl-Heisenberg frames. This yields a sufficient condition for two sampling transforms to have orthogonal ranges, and two analysis operators for wavelet and Weyl-Heisenberg frames to have orthogonal ranges. The sufficient condition is easy to compute in terms of the periodization of the Fourier transform of the frame generators.Comment: 20 pages; contact author: Eric Webe

    A comparative study of structured and un-structured remote data access in distributed computing systems

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    Recently, the use of distributed computing systems has been growing rapidly due to the result of cheap and advanced microelectronic technology. In addition to the decrease in hardware costs, the tremendous development in machine to machine communication interfaces, especially in local area networking, also favours the use of distributed systems. Distributed systems often require remote access to data stored at different sites. Generally, two models of access to remote data storage exist: the un structured and structured models. In the former, data is simply stored as row of bytes, whereas in the latter, data is stored along with the associated access codes. The objective of this thesis is to compare these two models and hence determines the tradeoffs of each model. First of all, an extended review of the field of distributed data access is provided which addressing key issues such as the basic design principles of distributed computing systems, the notions of abstract data types, data inheritance, data type system and data persistence. Secondly, a distributed system is implemented using the persistent programming language PS-algol and the high level language C in conjunction with the remote procedure call facilities available in Unix(^1) 4.2 BSD operating system. This distributed system makes extensive use of Unix's software tools and hence it is called DCSUNIX for Distributed Computing System on UNIX. Thirdly, two specific applications which employ the implemented system will be given so that a comparison can be made between the two remote data access models mentioned above. Finally, the implemented system is compared with the criteria established earlier in the thesis. keywords: abstract data types, class, database management, data persistence, information hiding, inheritance, object oriented programming, programming languages, remote procedure calls, transparency, and type checking

    More than a Wishful Dream

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    “More than a Wishful Dream” is a musical drama that explores the Christmas story through the eyes of Joseph. The author hopes to bring a realization that the Christmas story was an event that truly happened by exploring the emotional and cultural realities surrounding the birth of Christ through the musical. This thesis also includes a study on the different elements of playwriting, musical theatre and songwriting. These elements were compiled and incorporated into the musical as part of the thesis. In the musical, Joseph dreams to be great like his forefathers and to save his people from suffering. However, Joseph has to abandon his people’s approval if he is to obey God. In the end, Joseph learns that greatness is not achieved by doing great things, but rather by obeying the God who is great
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