Search results for "discrete [space-time]"

showing 10 items of 2035 documents

Metilazione del DNA in artrite reumatoide

2005

Lo stato di metilazione del DNA genomico e del gene PTHrP è stato valutato con tecniche molecolari e citogenetiche in artrite reumatoide (AR), patologia autoimmune caratterizzata anche da alta incidenza di linfomi e da ipercalcemia per overespressione del gene PTHrP. La metilazione del DNA, infatti, ha un ruolo critico nello sviluppo delle malattie neoplastiche; il gene PTHrP avendo tre promotori uno dei quali contiene un’isola CpG è un buon candidato per la deregolazione da alterato pattern di metilazione locale. Le indagini sulla metilazione genomica, condotte su DNA estratto da sangue periferico di pazienti e di donatori e amplificato in reazioni di Methylation-Sensitive Arbitrarily Prim…

Settore BIO/18 - Geneticainstead chromosomes of controls were almost uniformly decorated by brilliant grains. Studies on methylation of PTHrP gene promoter 2 performed on five CpG island internal sites using the Methylation-Sensitive Restriction Endonuclease Multiplex (MSREM)-PCR showed that one of the sites nearest the trascription starting point is heavy methylated in a significantly high number of RA patients. Thus RA seems to be characterized by genomewide hypomethylation associated with local hypermethylation like the most part of tumors. This result raises the possibility that susceptibility to lymphomas is related to abnormal DNA methylation levels and suggests the opportunity to evaluate the DNA methylation status in RA patientin fact the demethylating therapies together with diet and life style can act towards an increase of tumor risk. Future studies using a larger number of subjects could confirm these findings.Rheumatoid Arthritis (RA) is a chronic multisystem inflammatory disease characterized by high recurrence of lymphomas as well as hypercalcemia due to PTHrP overexpression. Because of DNA methylation plays a critical role in development of neoplasias we determined in RA patients the global DNA methylation status and local methylation pattern of the CpG island of one of the three promoters of PTHrP gene utilizing molecular and cytogenetic techniques. Investigations performed on DNA from peripheral blood of patients and donors amplified by Methylation-Sensitive Arbitrarily Primed (MeS-AP)-PCR indicated that RA is strongly associated with global DNA hypomethylation. Similarly chromosomal DNA methylation pattern analysis by indirect immunofluorescence technique with anti 5-methylcitosine antibody showed all peripheral lymphocyte metaphases from RA patients with chromosomes weakly fluorescent without discrete grain
researchProduct

A memetic approach to discrete tomography from noisy projections

2010

Discrete tomography deals with the reconstruction of images from very few projections, which is, in the general case, an NP-hard problem. This paper describes a new memetic reconstruction algorithm. It generates a set of initial images by network flows, related to two of the input projections, and lets them evolve towards a possible solution, by using crossover and mutation. Switch and compactness operators improve the quality of the reconstructed images during each generation, while the selection of the best images addresses the evolution to an optimal result. One of the most important issues in discrete tomography is known as the stability problem and it is tackled here, in the case of no…

Settore INF/01 - InformaticaCrossoverComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONEvolutionary algorithmDiscrete tomographyReconstruction algorithmImage processingIterative reconstructionStability problemArtificial IntelligenceRobustness (computer science)Signal ProcessingMemetic algorithmComputer Vision and Pattern RecognitionDiscrete tomographyAlgorithmSoftwareEvolutionary reconstruction.MathematicsPattern Recognition
researchProduct

Telecom-compatible, affordable and scalable quantum technologies

2022

The realistic implementation of quantum architectures relies on the development of scalable, resource-efficient platforms that are compatible with CMOS technologies as well as fiber networks. This work demonstrates novel schemes utilized for time-/frequency-bin entanglement generation and processing by leveraging existing telecommunications and integrated photonics infrastructures.

Settore ING-INF/02 - Campi ElettromagneticiIntegrated quantum optics complex photon states quantum frequency combs silicon-based chips microring resonators spiral waveguides integrated Mach-Zehnder interferometers discrete time and frequency modes photonic qubits and qudits
researchProduct

Clifford Rotors for Conceptual Representation in Chatbots

2013

In this abstract we introduce an unsupervised sub-symbolic natural language sentences encoding procedure aimed at catching and representing into a Chatbot Knowledge Base (KB) the concepts expressed by an user interacting with a robot. The chatbot KB is coded in a conceptual space induced from the application of the Latent Semantic Analysis (LSA) paradigm on a corpus of documents. LSA has the effect of decomposing the original relationships between elements into linearly-independent vectors. Each basis vector can be considered therefore as a "conceptual coordinate", which can be tagged by the words which better characterize it. This tagging is obtained by performing a (TF-IDF)-like weighting…

Settore ING-INF/05 - Sistemi Di Elaborazione Delle InformazioniDiscrete mathematicsComputer sciencebusiness.industryLatent semantic analysisInformationSystems_INFORMATIONSTORAGEANDRETRIEVALRepresentation (systemics)computer.software_genreChatbotGeometric algebraKnowledge baseArtificial IntelligenceEncoding (semiotics)chatbot clifford algebraArtificial intelligenceDialog systembusinesscomputerNatural language processingNatural language
researchProduct

Random Stability of an Additive-Quadratic-Quartic Functional Equation

2010

Using the fixed point method, we prove the generalized Hyers-Ulam stability of the following additive-quadratic-quartic functional equation f(x+2y)+f(x−2y)=2f(x+y)+2f(−x−y)+2f(x−y)+2f(y−x)−4f(−x)−2f(x)+f(2y)+f(−2y)−4f(y)−4f(−y) in complete random normed spaces.

Settore MAT/05 - Analisi MatematicaApplied Mathematicslcsh:MathematicsDiscrete Mathematics and Combinatoricslcsh:QA1-939AnalysisRandom normed space fixed point generalized Hyers-Ulam stability additive-quadratic-quartic functional equationJournal of Inequalities and Applications
researchProduct

Denjoy and P-path integrals on compact groups in an inversion formula for multiplicative transforms

2009

Abstract Denjoy and P-path Kurzweil-Henstock type integrals are defined on compact subsets of some locally compact zero-dimensional abelian groups. Those integrals are applied to obtain an inversion formula for the multiplicative integral transform.

Settore MAT/05 - Analisi MatematicaGeneral MathematicsPath integral formulationMultiplicative functionMathematical analysisLocally compact spaceDenjoy integral multiplicative transformsAbelian groupLocally compact groupIntegral transformInversion (discrete mathematics)MathematicsVolume integral
researchProduct

Discrete Time Portfolio Selection with Lévy Processes

2007

This paper analyzes discrete time portfolio selection models with Lévy processes. We first implement portfolio models under the hypotheses the vector of log-returns follow or a multivariate Variance Gamma model or a Multivariate Normal Inverse Gaussian model or a Brownian Motion. In particular, we propose an ex-ante and an ex-post empirical comparisons by the point of view of different investors. Thus, we compare portfolio strategies considering different term structure scenarios and different distributional assumptions when unlimited short sales are allowed.

Settore SECS-S/06 - Metodi mat. dell'economia e Scienze Attuariali e Finanziarieterm structureexpected utilitySubordinated Lévy models; term structure; expected utility; portfolio strategiesportfolio strategiesMultivariate normal distributionSubordinated Lévy modelsVariance-gamma distributionInverse Gaussian distributionsymbols.namesakeSettore SECS-S/06 -Metodi Mat. dell'Economia e d. Scienze Attuariali e Finanz.Discrete time and continuous timesymbolsEconometricsPortfolioSubordinated Lévy models term structure expected utility portfolio strategiesPost-modern portfolio theoryPortfolio optimizationModern portfolio theoryMathematics
researchProduct

Adaptive motion estimation and video vector quantization based on spatiotemporal non-linearities of human perception

1997

The two main tasks of a video coding system are motion estimation and vector quantization of the signal. In this work a new splitting criterion to control the adaptive decomposition for the non-uniform optical flow estimation is exposed. Also, a novel bit allocation procedure is proposed for the quantization of the DCT transform of the video signal. These new approaches are founded on a perception model that reproduce the relative importance given by the human visual system to any location in the spatial frequency, temporal frequency and amplitude domain of the DCT transform. The experiments show that the proposed procedures behave better than their equivalent (fixed-block-size motion estim…

Signal processingAdaptive algorithmComputer sciencebusiness.industryTrellis quantizationQuantization (signal processing)ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONVector quantizationIterative reconstructionOptical flow estimationMotion estimationComputer Science::MultimediaHuman visual system modelDiscrete cosine transformComputer visionArtificial intelligencebusinessQuantization (image processing)
researchProduct

A fast recursive algorithm to compute local axial moments

2001

The paper describes a fast algorithm to compute local axial moments used in the algorithm of discrete symmetry transform (DST). The basic idea is grounded on fast recursive implementation of respective linear filters by using the so-called primitive kernel functions since the moment computation can be performed in the framework of linear filtering. The main result is that the computation of the local axial moments is independent of the kernel size, i.e. of the order O(1) per data point (pixel). This result is of relevance whenever the DST is used to face with real time computer vision problems. The experimental results confirm the time complexity predicted by the theory.

Signal processingComputationMoment (mathematics)Control and Systems EngineeringFace (geometry)Signal ProcessingPoint (geometry)Computer Vision and Pattern RecognitionElectrical and Electronic EngineeringTime complexityAlgorithmSoftwareLinear filterMathematicsDiscrete symmetrySignal Processing
researchProduct

On the Design of Fast Wavelet Transform Algorithms With Low Memory Requirements

2008

In this paper, a new algorithm to efficiently compute the two-dimensional wavelet transform is presented. This algorithm aims at low memory consumption and reduced complexity, meeting these requirements by means of line-by-line processing. In this proposal, we use recursion to automatically place the order in which the wavelet transform is computed. This way, we solve some synchronization problems that have not been tackled by previous proposals. Furthermore, unlike other similar proposals, our proposal can be straightforwardly implemented from the algorithm description. To this end, a general algorithm is given which is further detailed to allow its implementation with a simple filter bank…

Signal processingLifting schemeComputer scienceSecond-generation wavelet transformStationary wavelet transformWavelet transformImage processingCascade algorithmFilter bankWavelet packet decompositionMedia TechnologyDiscrete cosine transformCodecElectrical and Electronic EngineeringFast wavelet transformAlgorithmEncoderData compressionImage compressionIEEE Transactions on Circuits and Systems for Video Technology
researchProduct