Search results for "Transform"

showing 10 items of 3975 documents

Estimates for Sums of Eigenvalues of the Free Plate via the Fourier Transform

2017

Using the Fourier transform, we obtain upper bounds for sums of eigenvalues of the free plate.

Tension (physics)Applied MathematicsSums of eigenvaluesMathematical analysisFree plate35P15 35J40 74K20General MedicineMathematics::Spectral TheoryDomain (mathematical analysis)Ambient spaceMathematics - Spectral TheoryPhysics::Fluid Dynamicssymbols.namesakeFourier transformVolume (thermodynamics)Dimension (vector space)Bilaplace operatorSettore MAT/05 - Analisi MatematicasymbolsFOS: MathematicsSpectral Theory (math.SP)AnalysisEigenvalues and eigenvectorsMathematics
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Generalized Virasoro anomaly and stress tensor for dilaton coupled theories

2003

We derive the anomalous transformation law of the quantum stress tensor for a 2D massless scalar field coupled to an external dilaton. This provides a generalization of the Virasoro anomaly which turns out to be consistent with the trace anomaly. We apply it together with the equivalence principle to compute the expectation values of the covariant quantum stress tensor on a curved background. Finally we briefly illustrate how to evaluate vacuum polarization and Hawking radiation effects from these results.

Tensor contractionPhysicsAstrofísicaHigh Energy Physics - TheoryNuclear and High Energy PhysicsCauchy stress tensorDilaton coupled theoriesHawking radiationFOS: Physical sciencesGeneral Relativity and Quantum Cosmology (gr-qc)General Relativity and Quantum CosmologyHigh Energy Physics::TheoryGeneral Relativity and Quantum CosmologyClassical mechanicsHigh Energy Physics - Theory (hep-th)Stress tensorDilatonCovariant transformationVacuum polarizationVacuum polarizationAnomaly (physics)Tensor densityScalar fieldVirasoro and trace anomaliesMathematical physics
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Synthesis of Nonplanar Graphene Nanoribbon with Fjord Edges

2021

As a new family of semiconductors, graphene nanoribbons (GNRs), nanometer-wide strips of graphene, have appeared as promising candidates for next-generation nanoelectronics. Out-of-plane deformation of π-frames in GNRs brings further opportunities for optical and electronic property tuning. Here we demonstrate a novel fjord-edged GNR (FGNR) with a nonplanar geometry obtained by regioselective cyclodehydrogenation. Triphenanthro-fused teropyrene 1 and pentaphenanthro-fused quateropyrene 2 were synthesized as model compounds, and single-crystal X-ray analysis revealed their helically twisted conformations arising from the [5]helicene substructures. The structures and photophysical properties …

Terahertz radiationCrystallography X-RayBiochemistryCatalysislaw.inventionchemistry.chemical_compoundsymbols.namesakeColloid and Surface ChemistrylawSpectroscopy Fourier Transform InfraredPolycyclic CompoundsDensity Functional TheoryPyrenesbusiness.industryGrapheneCommunicationStereoisomerismGeneral ChemistryNanostructuresSemiconductorHelicenechemistryNanoelectronicsChemical physicssymbolsDensity functional theoryGraphitebusinessRaman spectroscopyGraphene nanoribbons
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ChemInform Abstract: Synthesis of Elemane Bis-lactones Structurally Related to Vernolepin.

2010

Abstract The chemical transformation of santonin into an elemane bis -lactone structurally related to the antitumour compound vernolepin is reported. The transformation of ring A of santonin into a hemiacetal δ-lactone was achieved in eleven steps. The spectroscopic characteristics of the synthetic product obtained in this way revealed that the proposed structure for the natural product should be revised.

Terpenechemistry.chemical_classificationchemistry.chemical_compoundChemical transformationNatural productchemistryStereochemistryVernolepinHemiacetalGeneral MedicineRing (chemistry)LactoneSantoninChemInform
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Automatic orientation and 3D modelling from markerless rock art imagery

2013

This paper investigates the use of two detectors and descriptors on image pyramids for automatic image orientation and generation of 3D models. The detectors and descriptors replace manual measurements and are used to detect, extract and match features across multiple imagery. The Scale-Invariant Feature Transform (SIFT) and the Speeded Up Robust Features (SURF) will be assessed based on speed, number of features, matched features, and precision in image and object space depending on the adopted hierarchical matching scheme. The influence of applying in addition Area Based Matching (ABM) with normalised cross-correlation (NCC) and least squares matching (LSM) is also investigated. The pipel…

Terrestrial laser scanningClose range imageryMatching (statistics)Computer scienceComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONScale-invariant feature transformBundle adjustmentAutomationOrientationBundle adjustmentMatchingComputer visionComputers in Earth SciencesEngineering (miscellaneous)Block (data storage)Ground truthOrientation (computer vision)business.industryPipeline (software)Atomic and Molecular Physics and OpticsComputer Science ApplicationsPhotogrammetryINGENIERIA CARTOGRAFICA GEODESIA Y FOTOGRAMETRIAArtificial intelligencebusinessISPRS Journal of Photogrammetry and Remote Sensing
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La Seconda Vita dell'Ambiente Costruito

2021

Il contributo inquadra i saggi, gli studi, le ricerche e progetti pubblicati sul numero 9 di AGATHÓN su ‘La Seconda Vita dell’Ambiente Costruito’, tema di interesse per il mondo accademico, delle professioni e dell’industria. Cambiamenti climatici, eccessivo consumo di suolo e di risorse non rinnovabili, produzione sempre crescente di rifiuti, emergenza pandemica e crisi socio-economica globale sono entrati di fatto nel nostro quotidiano: seppur drammatiche, per certi versi, tali questioni possono essere colte come un’opportunità per ripensare il modo e il mondo in cui viviamo. In questo contesto di ‘rivoluzione’(Floridi, 2020) e di ‘policrisi’ (Losasso, 2020), e con riferimento specifico a…

The contribution frames the essays studies research and projects published in issue 9 of AGATHÓN on ‘The SecondLife of the Built Environment’ an interesting topic for universities businesses and industry. Climate changes excessive use of soil renewable resources ever-increasing production of waste the current pandemic emergency and the global socio-economic crisis have in fact entered our daily life. Even if these are tragic issues they can be somehow seized as an opportunity to rethink the way we live and our world. In this ‘revolutionary’ (Floridi 2020) and ‘polycrisis’ (Losasso 2020) context specifically referring to the building industry the Academy the Research and Industry worlds are called to give answers – based on sustainability and the principles of the Green Deal but also and mostly of the new Bauhaus – that can encourage reconsiderations and re-orientations of processes and products new projects on places buildings objects and materials able to positively affect the governance of the global change that our planet and humanity need able to give a ‘new life’ to the built and/or transformed environment at any scaleSettore ICAR/12 - Tecnologia Dell'Architettura
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Abitare nel reale. Dalla crisi della periferia alla tessitura di nuove relazioni contestuali

2019

I progetti redatti per “Palermo Sud-Est” sono il risultato di un Laboratorio di Laurea strutturatosi attraverso incontri, seminari, comunicazioni specialistiche, esposizioni critiche, che – in una strategia condivisa – ha visto ogni studente elaborare il proprio lavoro nel confronto con gli altri attori del Laboratorio stesso. La ricerca sui “progetti urbani” è stata impostata di modo che ogni laureando fosse messo a conoscenza dei progetti svolti nello stesso ambito territoriale dai colleghi che l’avevano preceduto, così da poter operare in continuità e contribuire a formulare un ragionamento unitario, nel quale ogni progetto costituisse continuazione, verifica o anche variante dei precede…

The projects prepared for "Palermo South-East" are the result of a Graduate Laboratory structured through meetings seminars specialist communications critical exhibitions which - in a shared strategy - saw each student elaborate their work in comparison with others actors of the same Laboratory. The research on "urban projects" was set so that each graduating student was made aware of the projects carried out in the same geographical area by the colleagues who had preceded it so as to be able to operate in continuity and contribute to formulating a unitary reasoning in which each project constituted continuation verification or even variant of the previous ones. These coordinated works have pursued two fundamental objectives: the strengthening of infrastructures and the establishment of specialized public buildings with superior functions aimed at requalifying and regenerating various critical situations with particular attention to the relationship between context and life scenarios. Thus each designer while dealing with a main functional program simultaneously deals with various issues such as the rationalization of the road system the redevelopment of existing buildings the design and refunctionalization of urban services (for example the transformed Central Station in the hotel or the project of a great Mosque)several degree theses have addressed as the main theme or as a question in the background the design of a new bed for the Oreto river and the relative establishment of a park facing it. In this desire to "patch up the wounds" in the different areas of "Palermo South-East" in close relationship with the vicissitudes of the place there is a continuous reference to architectures of all time and some questions involving the functional program are suggested - that identifies the character (or perhaps "type") of what is to be inserted in a given context - and the qualities of living reality as a pivotal material in the design process.Settore ICAR/14 - Composizione Architettonica E Urbana
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Evaluation of GPU-based Seed Generation for Computational Genomics Using Burrows-Wheeler Transform

2012

Unprecedented production of short reads from the new high-throughput sequencers has posed challenges to align short reads to reference genomes with high sensitivity and high speed. Many CPU-based short read aligners have been developed to address this challenge. Among them, one popular approach is the seed-and-extend heuristic. For this heuristic, the first and foremost step is to generate seeds between the input reads and the reference genome, where hash tables are the most frequently used data structure. However, hash tables are memory-consuming, making it not well-suited to memory-stringent many-core architectures, like GPUs, even though they usually have a nearly constant query time com…

Theoretical computer scienceBurrows–Wheeler transformComputational complexity theoryComputer scienceComputational genomicsParallel computingData structureTime complexityHash table2012 IEEE 26th International Parallel and Distributed Processing Symposium Workshops & PhD Forum
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Boosting Textual Compression in Optimal Linear Time

2005

We provide a general boosting technique for Textual Data Compression. Qualitatively, it takes a good compression algorithm and turns it into an algorithm with a better compression performance guarantee. It displays the following remarkable properties: (a) it can turn any memoryless compressor into a compression algorithm that uses the “best possible” contexts; (b) it is very simple and optimal in terms of time; and (c) it admits a decompression algorithm again optimal in time. To the best of our knowledge, this is the first boosting technique displaying these properties.Technically, our boosting technique builds upon three main ingredients: the Burrows--Wheeler Transform, the Suffix Tree d…

Theoretical computer scienceBurrows–Wheeler transformSuffix treeString (computer science)Data_CODINGANDINFORMATIONTHEORYBurrows-Wheeler transformSubstringArithmetic codinglaw.inventionLempel-Ziv compressorsArtificial IntelligenceHardware and ArchitectureControl and Systems Engineeringlawtext compressionempirical entropyArithmetic codingGreedy algorithmTime complexityAlgorithmSoftwareInformation SystemsMathematicsData compression
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Efficient evaluation for a subset of recursive queries

1991

Abstract We consider the efficient evaluation of recursive queries in logic databases where the queries are expressed using a Datalog program (function-free Horn-clause program) that contains only regularly or linearly recursive predicates. Using well-known results on graph traversal, we develop an efficient algorithm for evaluating relations defined by a binary-chain program. We also present a transformation by which the evaluation of a subset of queries involving nonbinary relations can be reduced to the evaluation of binary-chain queries. This transformation is guided by the choice of bound arguments in the query, and the bindings are propagated through the program so that in the evaluat…

Theoretical computer scienceComputer scienceLogic0102 computer and information sciences02 engineering and technologycomputer.software_genre01 natural sciencesDatalogSet (abstract data type)020204 information systemsGraph traversal0202 electrical engineering electronic engineering information engineeringComputer Science::Databasescomputer.programming_languageMathematicsDiscrete mathematicsProgramming languageBinary relationEfficient algorithmInformationSystems_DATABASEMANAGEMENT16. Peace & justiceTransformation (function)TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGESrestrict010201 computation theory & mathematicscomputerProceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems - PODS '87
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