Search results for "Crete"

showing 10 items of 2495 documents

Algebraic Structures of Rough Sets

1994

This paper deals with some algebraic and set-theoretical properties of rough sets. Our considerations are based on the original conception of rough sets formulated by Pawlak [4, 5]. Let U be any fixed non-empty set traditionally called the universe and let R be an equivalence relation on U. The pair A = (U, R) is called the approximation space. We will call the equivalence classes of the relation R the elementary sets. We denote the family of elementary sets by U/R. We assume that the empty set is also an elementary set. Every union of elementary sets will be called a composed set. We denote the family of composed sets by ComR. We can characterize each set X ⊆ U using the composed sets [5].

Set (abstract data type)Discrete mathematicsRelation (database)Algebraic structureEquivalence relationEmpty setRough setAlgebraic numberSpace (mathematics)Mathematics
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Words and Patterns

2002

In this paper some new ideas, problems and results on patterns are proposed. In particular, motivated by questions concerning avoidability, we first study the set of binary patterns that can occur in one infinite binary word, comparing it with the set of factors of the word. This suggests a classification of infinite words in terms of the "difference" between the set of its patterns and the set of its factors. The fact that each factor in an infinite word can give rise to several distinct patterns leads to study the set of patterns of a single finite word. This set, endowed with a natural order relation, defines a poset: we investigate the relationships between the structure of such a poset…

Set (abstract data type)Discrete mathematicsStructure (mathematical logic)Regular languageRelation (database)Binary numberComputer Science::Computation and Language (Computational Linguistics and Natural Language and Speech Processing)Natural orderPartially ordered setComputer Science::Formal Languages and Automata TheoryWord (computer architecture)Mathematics
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On a projective representation of chain geometries

1984

We define a distance d on the set of r-spaces of an n-space. By the transfer of d to the GrasmannianG=G(n, r) we obtain a distinguished class of normal rational curves of order 1, the “1-distance lines’, 1=1,..., r, which are in 1–1-correspondence to the so-called “generalized reguli of type (r, 1)”.

Set (abstract data type)Discrete mathematicsTransfer (group theory)Class (set theory)Pure mathematicsChain (algebraic topology)Order (group theory)Geometry and TopologyType (model theory)Rational normal curveProjective representationMathematicsJournal of Geometry
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Spectral properties of correlation matrices for some hierarchically nested factor models

2007

We show that spectral methods, such as Principal Component Analysis and Random Matrix Theory, are unable to reveal the hierarchical (or nested) structure of a set of mutivariate data. We consider the method introduced in M. Tumminello et al., EPL 78, 30006 (2007) to associate a hierarchical factor model with a set of data by making use of clustering algorithms. This is done by proving the existence of a bijective correspondence between a hierarchical tree and a factor model.

Set (abstract data type)Discrete mathematicsTree (data structure)Multiple correspondence analysisPrincipal component analysisBijectionCluster analysisRandom matrixFactor analysisMathematics
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Discrete-time static output-feedback semi-decentralized H<inf>∞</inf> controller design: An application to structural vibratio…

2012

In this work, we present a new and effective method to design discrete-time static output-feedback H ∞ controllers. This new method, based on a Linear Matrix Inequality (LMI) formulation, introduces a suitable transformation of the LMI variables that allows to obtain an explicit expression for the output-feedback gain matrix. Moreover, for problems involving a set of subsystems with information exchange constraints, a convenient structure on the LMI variables can be imposed in order to design semi-decentralized controllers, where the corresponding output-feedback gain matrix has a prescribed zero-nonzero structure. To illustrate the proposed methodology, discrete-time static velocity-feedba…

Set (abstract data type)Matrix (mathematics)Transformation (function)Discrete time and continuous timeControl theoryVibration controlLinear matrix inequalityExpression (mathematics)Mathematics2012 American Control Conference (ACC)
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Induced ℓ<inf>2</inf> control of discrete-time Takagi-Sugeno fuzzy systems with time-varying delays via dynamic output feedback

2012

This paper is concerned with analyzing a novel model transformation of discrete-time Takagi-Sugeno (T-S) fuzzy systems with time-varying delays and applying it to dynamic output feedback (DOF) controller design. A new auxiliary model is proposed by employing a new approximation for time-varying delay state, and then delay partitioning method is used to analyze the scaled small gain of this auxiliary model. A sufficient condition on discrete-time T-S fuzzy systems with time-varying delays, which guarantees the corresponding closed-loop system to be asymptotically stable and has an induced l 2 disturbance attenuation performance, is derived by employing the scaled small gain theorem. Then the…

Set (abstract data type)Small-gain theoremDiscrete time and continuous timeControl theoryStability theoryModel transformationFuzzy control systemState (functional analysis)computercomputer.programming_languageMathematics2012 IEEE 51st IEEE Conference on Decision and Control (CDC)
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Distribution patterns of the parrotfish Sparisoma cretense in the Plemmirio’s MPA

2016

Marine protected areas (MPAs), when designated correctly and managed well, provide a plethora of conservation benefits for current and future generations (i.e. increased habitat heterogeneity at the seascape level, increased abundance of threatened species and habitats, and maintenance of a full range of genotypes). The distribution pattern of an important target species from the Mediterranean Sea, the parrotfish Sparisoma cretense, was determined in the Plemmirio MPA (Siracuse, Italy) during summer of 2014. Sampling was carried out by means of underwater visual census techniques at two different depth (0/10 m and 10/20 m respectively) at four sampling sites within the reserve boundaries an…

Settore BIO/07 - EcologiaMediterranean MPAs target species Parrotfish Sparisoma cretense
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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
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Dense Geometry of Music and Visual Arts: Vanishing Points, Continuous Tonnetz, and Theremin Performance

2018

The dualism between continuous and discrete is relevant in music theory as well as in performance practice of musical instruments. Geometry has been used since longtime to represent relationships between notes and chords in tonal system. Moreover, in the field of mathematics itself, it has been shown that the continuity of real numbers can arise from geometrical observations and reasoning. Here, we consider a geometrical approach to generalize representations used in music theory introducing continuous pitch. Such a theoretical framework can be applied to instrument playing where continuous pitch can be naturally performed. Geometry and visual representations of concepts of music theory and…

Settore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciSettore INF/01 - Informaticamedia_common.quotation_subject05 social sciencesSettore ING-INF/02 - Campi Elettromagnetici06 humanities and the artsArtSettore MAT/04 - Matematiche ComplementariContinuum and discrete music theory050105 experimental psychology060404 musicComputer graphics (images)0501 psychology and cognitive sciencesVanishing pointTonnetz0604 artsmedia_common
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Paleoenvironmental and tectonic evolution of the Liassic carbonate platform succession of Mt. Maranfusa (central western Sicily)

2011

The upper part of the Liassic carbonate platform succession (Inici Fm., Hettangian-Sinemurian), outcropping at Mt. Maranfusa (central western Sicily) consists of a sequence of peritidal limestones, overlain by Jurassic to Cenozoic pelagic limestones and their siliciclastic Tertiary covers. The good exposure of this succession, pertaining to the trapanese domain, in the area between Palermo and Sciacca mountains, allowed to study in detail the facies sequences and structural features of the carbonate platform and of the sedimentary dikes, in order to improve knowledge on its paleoenvironmental and tectonic evolution. The Inici Fm. is constituted by subtidal cyclic sequences of wackestone\pac…

Settore GEO/02 - Geologia Stratigrafica E SedimentologicaCalcrete Paleokarst Neptunian dike Injection dike
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