4,079 research outputs found

    Communications for Next Generation single chip computers

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    It is the thesis of this report that much of what is presently thought to require specialized VLSI functions might instead be achieved by combinations of fast general purpose single chip computers with upgraded communication facilities. To this end, the characteristics of applications of this nature are first surveyed briefly and some working principles established. In the light of these, three different chip philosophies are explored in some detail. This study shows that some upgrading of typical single chip I/O will definitely be necessary, but that this upgrading does not have to be complex and that true multiprocessor-multibus operation could be achieved without excessive cost

    Dual WDVV Equations in N=2 Supersymmetric Yang-Mills Theory

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    This paper studies the dual form of Witten-Dijkgraaf-Verlinde-Verlinde (WDVV) equations in N=2 supersymmetric Yang-Mills theory by applying a duality transformation to WDVV equations. The dual WDVV equations called in this paper are non-linear differential equations satisfied by dual prepotential and are found to have the same form with the original WDVV equations. However, in contrast with the case of weak coupling calculus, the perturbative part of dual prepotential itself does not satisfy the dual WDVV equations. Nevertheless, it is possible to show that the non-perturbative part of dual prepotential can be determined from dual WDVV equations, provided the perturbative part is given. As an example, the SU(4) case is presented. The non-perturbative dual prepotential derived in this way is consistent to the dual prepotential obtained by D'Hoker and Phong.Comment: misprints are corrected, revtex, 10 page

    Common Hypercyclic Vectors for the Conjugate Class of a Hypercyclic Operator

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    Given a separable, infinite dimensional Hilbert space, it was recently shown by the authors that there is a path of chaotic operators, which is dense in the operator algebra with the strong operator topology, and along which every operator has the exact same dense GÎŽ set of hypercyclic vectors. In the present work, we show that the conjugate set of any hypercyclic operator on a separable, infinite dimensional Banach space always contains a path of operators which is dense with the strong operator topology, and yet the set of common hypercyclic vectors for the entire path is a dense GÎŽ set. As a corollary, the hypercyclic operators on such a Banach space form a connected subset of the operator algebra with the strong operator topology

    Mobile Phone Communication Innovation in Multiple Time and Space Zones: The Case of Hong Kong Culture

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    Hong Kong is probably one of the very few places in the world where it is generally acceptable to answer incoming mobile phone calls in public places or even in the middle of a business or social meeting. In many other parts of the world, this kind of behaviour would be considered impolite or even rude because it interrupts conversations or activities. There has been considerable research carried out on mobile phones and interruption, as well as mobile phones and culture. However, there is little evidence of research on the impact of culture on the specific notion of interruption caused by mobile phones. To fill this knowledge gap, this paper presents an ethnographic study about how the Hong Kong cultural features of fast pace, deal-making and sense of urgency result in a positive perception towards mobile phone interruption. The findings indicate that Hong Kong people have innovative mobile phone communication strategies, characteristically juggling multiple identities in their stressful work pace, virtually racing with time. Comparison with other contexts is made

    Atypical umbilical naevi: histopathological analysis of 20 cases

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110566/1/his12503.pd

    Antecedents Of Information Systems Habit In Sporadic Use Of Learning Systems: Personalization And Peer Effects

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    Research on Information Systems (IS) habit formation has been focused mostly on IS habit’s effect on IS continuance. Antecedents of IS habit formation, as reported in the literature, are primarily on users’ prior behavior and comprehensiveness of usage. Most of the literature focus on analyzing the relationship between users’ IS usage behavior and IS habit. Limited work has been reported to investigate genuine and practical ways to develop IS habit, as well as to address the issue of sporadic IS usage, which leads to different interpretations on IS habit and continuance. This study purports to address the theoretical gap on issues related to IS habit antecedents and sporadic IS usage habit in the educational context. Adopting an empirical survey in universities’ (sub-degree and postgraduate settings) learning systems usage, data from cross-sectional survey on learning systems usage on per-course basis is analyzed. Theoretically, our results suggest that IT functionality design (personalization) and social factor (peer effect) have strong and positive relationship on IS habit with respect to the sporadic usage nature of course based learning systems. Practically, we suggest some dimensions for teachers on curriculum design that facilitate IS habit development, e.g., maintaining an online community with substantial student peer input at the early stage of a course

    A Note on Fluxes in Six-Dimensional String Theory Backgrounds

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    We study the structure of warped compactifications of type IIB string theory to six space-time dimensions. We find that the most general four-manifold describing the internal dimensions is conformal to a Kahler manifold, in contrast with the heterotic case where the four-manifold must be conformally Calabi-Yau.Comment: 22 pages, phyzz

    Rosette‐like structures in the spectrum of spitzoid tumors

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    Background Spitz nevi demonstrate a diverse spectrum of morphologies. Recently, there have been two reported examples of Spitz nevi with rosette‐like structures similar to Homer‐Wright rosettes. Rosettes have also been described in melanomas and in a proliferative nodule arising in a congenital nevus. Methods A retrospective review of 104 cases of Spitz nevi and variants (n = 51), pigmented spindle cell nevi (n = 26), combined melanocytic nevi with features of Spitz (n = 8), atypical Spitz tumor ( AST , n = 9), and spitzoid melanoma (n = 10). Results Rosette‐like structures were present in 3 of the 104 cases (2.9%), including a compound Spitz nevus, a desmoplastic Spitz nevus, and an AST . All three cases demonstrated several foci of small nests of epithelioid cells with peripherally palisaded nuclei arranged around a central area of fibrillar eosinophilic cytoplasm. Immunohistochemical staining of the three spitzoid lesions demonstrated that the rosette‐like structures express S100 protein, Melan‐A, and neuron specific enolase ( NSE ) and lacked expression of neurofilament, glial fibrillary acidic protein and synaptophysin. Conclusions While uncommon, rosette‐like structures can occur as a focal feature in Spitz nevi and AST . Rosette‐like structures may represent a normal morphologic finding in Spitz nevi, and awareness of them may prevent misdiagnosis as a neural tumor or melanoma.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99651/1/cup12192.pd
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