917 resultados para quadratically hyponormal operators


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fuzzification is introduced into gray-scale mathematical morphology by using two-input one-output fuzzy rule-based inference systems. The fuzzy inferring dilation or erosion is defined from the approximate reasoning of the two consequences of a dilation or an erosion and an extended rank-order operation. The fuzzy inference systems with numbers of rules and fuzzy membership functions are further reduced to a simple fuzzy system formulated by only an exponential two-input one-output function. Such a one-function fuzzy inference system is able to approach complex fuzzy inference systems by using two specified parameters within it-a proportion to characterize the fuzzy degree and an exponent to depict the nonlinearity in the inferring. The proposed fuzzy inferring morphological operators tend to keep the object details comparable to the structuring element and to smooth the conventional morphological operations. Based on digital area coding of a gray-scale image, incoherently optical correlation for neighboring connection, and optical thresholding for rank-order operations, a fuzzy inference system can be realized optically in parallel. (C) 1996 Society of Photo-Optical Instrumentation Engineers.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Este estudo teve como finalidade, testar uma barreira contra a contaminação microbiológica em placas de contato, utilizadas em monitoramento de salas limpas para fabricação de produtos farmacêuticos estéreis. Durante o ano de 2007, foram realizados testes de contato com a utilização da mencionada barreira, e os resultados foram comparados com dados dos anos de, 2004, 2005 e 2006, quando a barreira não foi utilizada. Os ambientes utilizados para os testes foram duas salas limpas de uma planta farmacêutica localizada no Rio de Janeiro. Nos mencionados ambientes é necessário o uso de uma vestimenta especial, de forma a evitar que partículas do corpo dos operadores, bactérias e fungos, migrem para a superfície externa do uniforme e coloquem em risco a esterilidade dos produtos. Sendo assim, foi proposta a colocação de uma camiseta diretamente sobre a pele do operador durante todo o ano de 2007 de forma a evitar ou reduzir a possibilidade de migração dessas partículas; e os resultados foram comparados com os anos de 2004, 2005 e 2006, quando a camiseta não foi usada. Os testes demonstraram que houve uma redução de cerca de 50% na ocorrência de placas contaminadas. Com relação ao número total de colônias formadas, a redução foi de 75% na comparação com os anos de 2004 e 2005 e de 50% com relação ao ano de 2006

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A.G. Vulih has shown how an essentially unique intrinsic multiplication can be defined in certain types of Riesz spaces (vector lattices) L. In general, the multiplication is not universally defined in L, but L can always be imbedded in a large space L# in which multiplication is universally defined.

If ф is a normal integral in L, then ф can be extended to a normal integral on a large space L1(ф) in L#, and L1(ф) may be regarded as an abstract integral space. A very general form of the Radon-Nikodym theorem can be proved in L1(ф), and this can be used to give a relatively simple proof of a theorem of Segal giving a necessary and sufficient condition that the Radon-Nikodym theorem hold in a measure space.

In another application, the multiplication is used to give a representation of certain Riesz spaces as rings of operators on a Hilbert space.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The use of transmission matrices and lumped parameter models for describing continuous systems is the subject of this study. Non-uniform continuous systems which play important roles in practical vibration problems, e.g., torsional oscillations in bars, transverse bending vibrations of beams, etc., are of primary importance.

A new approach for deriving closed form transmission matrices is applied to several classes of non-uniform continuous segments of one dimensional and beam systems. A power series expansion method is presented for determining approximate transmission matrices of any order for segments of non-uniform systems whose solutions cannot be found in closed form. This direct series method is shown to give results comparable to those of the improved lumped parameter models for one dimensional systems.

Four types of lumped parameter models are evaluated on the basis of the uniform continuous one dimensional system by comparing the behavior of the frequency root errors. The lumped parameter models which are based upon a close fit to the low frequency approximation of the exact transmission matrix, at the segment level, are shown to be superior. On this basis an improved lumped parameter model is recommended for approximating non-uniform segments. This new model is compared to a uniform segment approximation and error curves are presented for systems whose areas very quadratically and linearly. The effect of varying segment lengths is investigated for one dimensional systems and results indicate very little improvement in comparison to the use of equal length segments. For purposes of completeness, a brief summary of various lumped parameter models and other techniques which have previously been used to approximate the uniform Bernoulli-Euler beam is a given.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Mössbauer technique has been used to study the nuclear hyperfine interactions and lifetimes in W182 (2+ state) and W183 (3/2- and 5/2- states) with the following results: g(5/2-)/g(2+) = 1.40 ± 0.04; g(3/2- = -0.07 ± 0.07; Q(5/2-)/Q(2+) = 0.94 ± 0.04; T1/2(3/2-) = 0.184 ± 0.005 nsec; T1/2(5/2-) >̰ 0.7 nsec. These quantities are discussed in terms of a rotation-particle interaction in W183 due to Coriolis coupling. From the measured quantities and additional information on γ-ray transition intensities magnetic single-particle matrix elements are derived. It is inferred from these that the two effective g-factors, resulting from the Nilsson-model calculation of the single-particle matrix elements for the spin operators ŝz and ŝ+, are not equal, consistent with a proposal of Bochnacki and Ogaza.

The internal magnetic fields at the tungsten nucleus were determined for substitutional solid solutions of tungsten in iron, cobalt, and nickel. With g(2+) = 0.24 the results are: |Heff(W-Fe)| = 715 ± 10 kG; |Heff(W-Co)| = 360 ± 10 kG; |Heff(W-Ni)| = 90 ± 25 kG. The electric field gradients at the tungsten nucleus were determined for WS2 and WO3. With Q(2+) = -1.81b the results are: for WS2, eq = -(1.86 ± 0.05) 1018 V/cm2; for WO3, eq = (1.54 ± 0.04) 1018 V/cm2 and ƞ = 0.63 ± 0.02.

The 5/2- state of Pt195 has also been studied with the Mössbauer technique, and the g-factor of this state has been determined to be -0.41 ± 0.03. The following magnetic fields at the Pt nucleus were found: in an Fe lattice, 1.19 ± 0.04 MG; in a Co lattice, 0.86 ± 0.03 MG; and in a Ni lattice, 0.36 ± 0.04 MG. Isomeric shifts have been detected in a number of compounds and alloys and have been interpreted to imply that the mean square radius of the Pt195 nucleus in the first-excited state is smaller than in the ground state.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Sufficient stability criteria for classes of parametrically excited differential equations are developed and applied to example problems of a dynamical nature.

Stability requirements are presented in terms of 1) the modulus of the amplitude of the parametric terms, 2) the modulus of the integral of the parametric terms and 3) the modulus of the derivative of the parametric terms.

The methods employed to show stability are Liapunov’s Direct Method and the Gronwall Lemma. The type of stability is generally referred to as asymptotic stability in the sense of Liapunov.

The results indicate that if the equation of the system with the parametric terms set equal to zero exhibits stability and possesses bounded operators, then the system will be stable under sufficiently small modulus of the parametric terms or sufficiently small modulus of the integral of the parametric terms (high frequency). On the other hand, if the equation of the system exhibits individual stability for all values that the parameter assumes in the time interval, then the actual system will be stable under sufficiently small modulus of the derivative of the parametric terms (slowly varying).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

If E and F are real Banach spaces let Cp,q(E, F) O ≤ q ≤ p ≤ ∞, denote those maps from E to F which have p continuous Frechet derivatives of which the first q derivatives are bounded. A Banach space E is defined to be Cp,q smooth if Cp,q(E,R) contains a nonzero function with bounded support. This generalizes the standard Cp smoothness classification.

If an Lp space, p ≥ 1, is Cq smooth then it is also Cq,q smooth so that in particular Lp for p an even integer is C∞,∞ smooth and Lp for p an odd integer is Cp-1,p-1 smooth. In general, however, a Cp smooth B-space need not be Cp,p smooth. Co is shown to be a non-C2,2 smooth B-space although it is known to be C smooth. It is proved that if E is Cp,1 smooth then Co(E) is Cp,1 smooth and if E has an equivalent Cp norm then co(E) has an equivalent Cp norm.

Various consequences of Cp,q smoothness are studied. If f ϵ Cp,q(E,F), if F is Cp,q smooth and if E is non-Cp,q smooth, then the image under f of the boundary of any bounded open subset U of E is dense in the image of U. If E is separable then E is Cp,q smooth if and only if E admits Cp,q partitions of unity; E is Cp,psmooth, p ˂∞, if and only if every closed subset of E is the zero set of some CP function.

f ϵ Cq(E,F), 0 ≤ q ≤ p ≤ ∞, is said to be Cp,q approximable on a subset U of E if for any ϵ ˃ 0 there exists a g ϵ Cp(E,F) satisfying

sup/xϵU, O≤k≤q ‖ Dk f(x) - Dk g(x) ‖ ≤ ϵ.

It is shown that if E is separable and Cp,q smooth and if f ϵ Cq(E,F) is Cp,q approximable on some neighborhood of every point of E, then F is Cp,q approximable on all of E.

In general it is unknown whether an arbitrary function in C1(l2, R) is C2,1 approximable and an example of a function in C1(l2, R) which may not be C2,1 approximable is given. A weak form of C∞,q, q≥1, to functions in Cq(l2, R) is proved: Let {Uα} be a locally finite cover of l2 and let {Tα} be a corresponding collection of Hilbert-Schmidt operators on l2. Then for any f ϵ Cq(l2,F) such that for all α

sup ‖ Dk(f(x)-g(x))[Tαh]‖ ≤ 1.

xϵUα,‖h‖≤1, 0≤k≤q

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Let M be an Abelian W*-algebra of operators on a Hilbert space H. Let M0 be the set of all linear, closed, densely defined transformations in H which commute with every unitary operator in the commutant M’ of M. A well known result of R. Pallu de Barriere states that if ɸ is a normal positive linear functional on M, then ɸ is of the form T → (Tx, x) for some x in H, where T is in M. An elementary proof of this result is given, using only those properties which are consequences of the fact that ReM is a Dedekind complete Riesz space with plenty of normal integrals. The techniques used lead to a natural construction of the class M0, and an elementary proof is given of the fact that a positive self-adjoint transformation in M0 has a unique positive square root in M0. It is then shown that when the algebraic operations are suitably defined, then M0 becomes a commutative algebra. If ReM0 denotes the set of all self-adjoint elements of M0, then it is proved that ReM0 is Dedekind complete, universally complete Riesz spaces which contains ReM as an order dense ideal. A generalization of the result of R. Pallu de la Barriere is obtained for the Riesz space ReM0 which characterizes the normal integrals on the order dense ideals of ReM0. It is then shown that ReM0 may be identified with the extended order dual of ReM, and that ReM0 is perfect in the extended sense.

Some secondary questions related to the Riesz space ReM are also studied. In particular it is shown that ReM is a perfect Riesz space, and that every integral is normal under the assumption that every decomposition of the identity operator has non-measurable cardinal. The presence of atoms in ReM is examined briefly, and it is shown that ReM is finite dimensional if and only if every order bounded linear functional on ReM is a normal integral.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A partir da leitura do livro Mínimos, Múltiplos e Comuns de João Gilberto Noll, este trabalho busca empreender um estudo sobre as relações entre a escrita do artista e tempo na figura dos instantes ficcionais, observando a questão do microrrelato e da exigência fragmentária (cf.P. Lacoue-Labarthe e Jean-Luc Nancy), na perspectiva do inacabado/unidade, o que projeta uma hipótese de conjunto constelar para a escrita de João Gilberto Noll. Inicialmente realiza-se uma reflexão de alguns temas importantes na fortuna crítica sobre o escritor, com a intenção de saber como estes reverberam na sua escrita para, em seguida, tratar do fragmento e suas perspectivas estéticas de inacabamento e de totalidade, com relação ao tempo e como dessas questões surge a metáfora crítica do instante ficcional. As leituras críticas usadas como operadores nortearam-se a partir das noções de fragmento (romântico), e de Acontecimento, relacionadas ao par conceitual Cronos/Aiôn deleuziano

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this thesis we are concerned with finding representations of the algebra of SU(3) vector and axial-vector charge densities at infinite momentum (the "current algebra") to describe the mesons, idealizing the real continua of multiparticle states as a series of discrete resonances of zero width. Such representations would describe the masses and quantum numbers of the mesons, the shapes of their Regge trajectories, their electromagnetic and weak form factors, and (approximately, through the PCAC hypothesis) pion emission or absorption amplitudes.

We assume that the mesons have internal degrees of freedom equivalent to being made of two quarks (one an antiquark) and look for models in which the mass is SU(3)-independent and the current is a sum of contributions from the individual quarks. Requiring that the current algebra, as well as conditions of relativistic invariance, be satisfied turns out to be very restrictive, and, in fact, no model has been found which satisfies all requirements and gives a reasonable mass spectrum. We show that using more general mass and current operators but keeping the same internal degrees of freedom will not make the problem any more solvable. In particular, in order for any two-quark solution to exist it must be possible to solve the "factorized SU(2) problem," in which the currents are isospin currents and are carried by only one of the component quarks (as in the K meson and its excited states).

In the free-quark model the currents at infinite momentum are found using a manifestly covariant formalism and are shown to satisfy the current algebra, but the mass spectrum is unrealistic. We then consider a pair of quarks bound by a potential, finding the current as a power series in 1/m where m is the quark mass. Here it is found impossible to satisfy the algebra and relativistic invariance with the type of potential tried, because the current contributions from the two quarks do not commute with each other to order 1/m3. However, it may be possible to solve the factorized SU(2) problem with this model.

The factorized problem can be solved exactly in the case where all mesons have the same mass, using a covariant formulation in terms of an internal Lorentz group. For a more realistic, nondegenerate mass there is difficulty in covariantly solving even the factorized problem; one model is described which almost works but appears to require particles of spacelike 4-momentum, which seem unphysical.

Although the search for a completely satisfactory model has been unsuccessful, the techniques used here might eventually reveal a working model. There is also a possibility of satisfying a weaker form of the current algebra with existing models.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this thesis, a collection of novel numerical techniques culminating in a fast, parallel method for the direct numerical simulation of incompressible viscous flows around surfaces immersed in unbounded fluid domains is presented. At the core of all these techniques is the use of the fundamental solutions, or lattice Green’s functions, of discrete operators to solve inhomogeneous elliptic difference equations arising in the discretization of the three-dimensional incompressible Navier-Stokes equations on unbounded regular grids. In addition to automatically enforcing the natural free-space boundary conditions, these new lattice Green’s function techniques facilitate the implementation of robust staggered-Cartesian-grid flow solvers with efficient nodal distributions and fast multipole methods. The provable conservation and stability properties of the appropriately combined discretization and solution techniques ensure robust numerical solutions. Numerical experiments on thin vortex rings, low-aspect-ratio flat plates, and spheres are used verify the accuracy, physical fidelity, and computational efficiency of the present formulations.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Whilst current methods for the isolation and enumeration of Cryptosporidium spp. oocysts in water have provided some insight into their occurrence and significance, they are regarded as being inefficient, variable and time-consuming, with much of the interpretation being left to the expertise of the analyst. Two expectations of novel developments are to reduce the variability and subjectivity associated with the isolation and identification of oocysts. Flocculation, immunomagnetisable and flow cytometric techniques, for concentrating oocysts from water samples, should prove more reliable than current methods, whilst the development of more avid and specific monoclonal antibodies in conjunction with the use of nuclear fluorochromes will aid identification. Further insight into the viability, taxonomy, species identification, infectivity and virulence of the parasite should be forthcoming through the use of techniques such as the polymerase chain reaction, in situ hybridisation and non-uniform alternating current electrical fields. Such information is necessary in order to enable microbiologists, epidemiologists, engineers, utility operators and regulators to assess the safety of a water supply, with respect to Cryptosporidium contamination, more effectively.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Esta tese se dedica ao estudo do corpo em sua qualidade sensível, buscando evidenciar que é sobre este que incidem as formas de dominação contemporâneas na medida em que o corpo vem sofrendo, na atualidade, um processo de anestesiamento em seu campo intensivo, seja por uma sobre-excitação da sensação ou, ao contrário, pelo seu apagamento. Tal anestesiamento decorre dos novos modos de subjetivação contemporâneos em que a vida se tornou o lócus privilegiado das intervenções dos poderes. O corpo entediado, esvaziado de suas forças singulares produtivas, tem sido resultante da complexa rede de ingerências a que tem sido exposto. Na condução das políticas de saúde, os saberes se organizam em suas regulamentações para indivíduos e grupo, fechando-os às diferenciações. A possibilidade da experiência alteritária se torna rarefeita, já que indivíduos e grupos reproduzem a lógica de desapropriação de seus próprios modos de sentir, de perceber o mundo. Os trabalhos pesquisados, nesta tese, seja na dança ou nas técnicas de mobilização dos corpos que desenvolvem métodos para experienciar seus movimentos e ritmos, permitem o acesso às condições sensíveis, por colocarem questões ao corpo que ultrapassam o saber racionalizado sobre o mesmo. Funcionando como novos operadores cognitivos, estes trabalhos sustentam um fazer-se dos corpos, nos seus processos subjetivantes, em que o paradoxo e alteridade possam emergir como resistência às formações decorrentes dos jogos de saber/poder contemporâneos. Na mesma direção, também, a psicanálise tem muito a contribuir a partir da reavaliação de suas práticas observando a condição sensível dos corpos e do repensar teórico deste lugar, o corpo, que como campo de virtualidades atravessado pelo coletivo, aproxima-se do estado inaugural da existência. Neste lugar, a subjetivação se dá no campo das forças, campo pulsional ao realizar sua preensão do mundo e produção de suas formas através dos processos de erotização do corpo. Algumas teorias psicanalíticas têm colaborado significativamente para a sofisticação de um saber em que o psiquismo é visto como encarnado. Essa leitura, ao não dissociar o corpo do psiquismo, busca romper com a lógica binária, característica da leitura clássica psicanalítica, destacando a importância dos afetos na clínica e viabilizando, deste modo, para o entendimento dos sintomas, o enlace definitivo do sujeito com a cultura. A forma das forças é o resultado de um processo que se realiza a partir das percepções decorrentes de um dado campo de afetação, intensivo. Assim a possibilidade de sustentação de formas singulares de existência está relacionada à capacidade em acessar este campo das forças, entendido como um campo que permite as operações de construção e desconstrução do universo simbólico. Na aproximação da dimensão crítica envolvida nos estudos sobre a corporeidade, os estados patológicos podem ser compreendidos, então, como resistência aos imperativos das organizações codificadas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Esta tese tem como objetivo analisar o folhado textual da crônica jornalística de Antônio Maria e de Joaquim Ferreira dos Santos, investigando os operadores que agem na produção de sentido, sobretudo os aspectos enunciativos, como as vozes presentes na situação discursiva e os contextos em que se dão tais relações, e ainda atentar para a importância da palavra que desperta a paixão pelo texto, que leva a uma reflexão crítica sobre o seu tempo e sua história.Por meio da crônica desses dois autores, investigar a importância deste gênero textual nos atuais veículos midiáticos, reconhecendo neste gênero um importante papel de identidade cultural da sociedade brasileira. Perceber que, de certa forma, a função catártica da crônica jornalística de Antônio Maria e de Joaquim Ferreira dos Santos pode levar o leitor a sua própria identificação com o mundo que o cerca e com o espaço em que está inserido papel, afinal, da leitura de um texto, mais ainda, de um texto com traços literários. Sabendo, certamente, que é a língua, a palavra, a sustentação de todo esse processo