197,332 research outputs found
A brief historical perspective of the Wiener-Hopf technique
Full text linkIt is a little over 75 years since two of the most important mathematicians of the 20th century collaborated on finding the exact solution of a particular equation with semi-infinite convolution type integral operator. The elegance and analytical sophistication of the method, now called the Wiener–Hopf technique, impress all who use it. Its applicability to almost all branches of engineering, mathematical physics and applied mathematics is borne out by the many thousands of papers published on the subject since its conception. The Wiener–Hopf technique remains an extremely important tool for modern scientists, and the areas of application continue to broaden. This special issue of the Journal of Engineering Mathematics is dedicated to the work of Wiener and Hopf, and includes a number of articles which demonstrate the relevance of the technique to a representative range of model problems
Wiener modelling and model predictive control for wastewater applications
No full textThe research presented in this paper aims to demonstrate the application of predictive control to an integrated wastewater system with the use of the wiener modeling approach. This allows the controlled process, dissolved oxygen, to be considered to be composed of two parts: the linear dynamics, and a static nonlinearity, thus allowing control other than common approaches such as gain-scheduling, or switching, for series of linear controllers. The paper discusses various approaches to the modelling required for control purposes, and the use of wiener modelling for the specific application of integrated waste water control. This paper demonstrates this application and compares with that of another nonlinear approach, fuzzy gain-scheduled control
Regularidade de operadores de Wiener-Hopf mais Hankel
Full text linkDoutoramento em MatemáticaIn this thesis we consider Wiener-Hopf-Hankel operators with Fourier symbols
in the class of almost periodic, semi-almost periodic and piecewise almost
periodic functions. In the first place, we consider Wiener-Hopf-Hankel
operators acting between L2 Lebesgue spaces with possibly different Fourier
matrix symbols in the Wiener-Hopf and in the Hankel operators. In the
second place, we consider these operators with equal Fourier symbols and
acting between weighted Lebesgue spaces Lp(R;w), where 1 < p < 1
and w belongs to a subclass of Muckenhoupt weights. In addition, singular
integral operators with Carleman shift and almost periodic coefficients are
also object of study. The main purpose of this thesis is to obtain regularity
properties characterizations of those classes of operators. By regularity
properties we mean those that depend on the kernel and cokernel of the
operator. The main techniques used are the equivalence relations between
operators and the factorization theory.
An invertibility characterization for the Wiener-Hopf-Hankel operators with
symbols belonging to the Wiener subclass of almost periodic functions APW
is obtained, assuming that a particular matrix function admits a numerical
range bounded away from zero and based on the values of a certain mean
motion. For Wiener-Hopf-Hankel operators acting between L2-spaces and with possibly
different AP symbols, criteria for the semi-Fredholm property and for
one-sided and both-sided invertibility are obtained and the inverses for all
possible cases are exhibited. For such results, a new type of AP factorization
is introduced.
Singular integral operators with Carleman shift and scalar almost periodic coefficients
are also studied. Considering an auxiliar and simpler operator, and
using appropriate factorizations, the dimensions of the kernels and cokernels
of those operators are obtained.
For Wiener-Hopf-Hankel operators with (possibly different) SAP and PAP
matrix symbols and acting between L2-spaces, criteria for the Fredholm
property are presented as well as the sum of the Fredholm indices of the
Wiener-Hopf plus Hankel and Wiener-Hopf minus Hankel operators.
By studying dependencies between different matrix Fourier symbols of
Wiener-Hopf plus Hankel operators acting between L2-spaces, results about
the kernel and cokernel of those operators are derived.
For Wiener-Hopf-Hankel operators acting between weighted Lebesgue
spaces, Lp(R;w), a study is made considering equal scalar Fourier symbols
in the Wiener-Hopf and in the Hankel operators and belonging to the
classes of APp;w, SAPp;w and PAPp;w. It is obtained an invertibility characterization
for Wiener-Hopf plus Hankel operators with APp;w symbols. In
the cases for which the Fourier symbols of the operators belong to SAPp;w
and PAPp;w, it is obtained semi-Fredholm criteria for Wiener-Hopf-Hankel
operators as well as formulas for the Fredholm indices of those operators.Nesta tese consideramos operadores de Wiener-Hopf-Hankel com símbolos
de Fourier nas classes das funções quase-periódicas, semi-quase periódicas
e quase periódicas por troços. Começamos por considerar operadores de
Wiener-Hopf-Hankel actuando entre espaços de Lebesgue L2 com símbolos
matriciais de Fourier possivelmente diferentes nos operadores de Wiener-
Hopf e de Hankel. Seguidamente, consideramos estes operadores com símbolos
de Fourier iguais actuando entre espaços de Lebesgue com pesos
Lp(R;w), onde 1 < p < 1 e w pertence a uma subclasse de pesos de
Muckenhoupt. Adicionalmente, são também objecto de estudo operadores
singulares integrais com deslocamento de Carleman e coeficientes quaseperiódicos.
O objectivo principal desta tese é obter caracterizações para tais
classes de operadores no que refere às suas propriedades de regularidade. Por
propriedades de regularidade nós designamos aquelas propriedades que dependem
do núcleo e do co-núcleo do operador. As principais técnicas usadas
são as relações de equivalência entre operadores e a teoria da factorização.
Uma caracterização da invertibilidade de operadores de Wiener-Hopf-Hankel
com símbolos pertencentes à subclasse de Wiener de funções quaseperiódicas
APW é obtida, assumindo que uma particular função matricial
admite um contradomínio numérico limitado fora de zero e baseando-nos
nos valores uma certa média de deslocamento. Para os operadores de Wiener-Hopf-Hankel actuando entre espaços de
Lebesgue L2 e com símbolos AP possivelmente diferentes, critérios para
a propriedade de semi-Fredholm e para a invertibilidade lateral e bi-lateral
são obtidos e inversos para todos os casos possíveis são apresentados. Com
vista a tais resultados, um novo tipo de factorização AP é introduzido.
Operadores singulares integrais com deslocamento de Carleman e com coeficientes
escalares quase-periódicos são também estudados. Considerando
um operador auxiliar mais simples e usando factorizações apropriadas, as
dimensões dos núcleos e dos co-núcleos destes operadores são obtidas.
Para operadores de Wiener-Hopf-Hankel com símbolos matriciais SAP e
PAP (possivelmente diferentes) actuando entre espaços de Lebesgue L2,
critérios para a propriedade de Fredholm são apresentados tal como a soma
dos índices de Fredholm dos operadores de Wiener-Hopf mais Hankel e
Wiener-Hopf menos Hankel.
Estudando dependências entre diferentes símbolos matriciais de Fourier dos
operadores de Wiener-Hopf mais Hankel actuando entre espaços de Lebesgue
L2, conclusões são obtidas acerca do núcleo e do co-núcleo destes operadores.
Para operadores de Wiener-Hopf-Hankel actuando entre espaços de Lebesgue
com pesos, Lp(R;w), é feito um estudo considerando símbolos de Fourier
escalares e iguais nos operadores de Wiener-Hopf e de Hankel e pertencentes
às classes APp;w, SAPp;w e PAPp;w. É obtida uma caracterização da invertibilidade
para operadores de Wiener-Hopf mais Hankel com símbolos APp;w.
No caso em que os símbolos de Fourier dos operadores pertencem a SAPp;w
e PAPp;w, são obtidos critérios de semi-Fredholm para os operadores de
Wiener-Hopf-Hankel assim como fórmulas para os índices de Fredholm de
tais operadores
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Modeling of complex-valued Wiener systems using B-spline neural network
No full textIn this brief, a new complex-valued B-spline neural network is introduced in order to model the complex-valued Wiener system using observational input/output data. The complex-valued nonlinear static function in the Wiener system is represented using the tensor product from two univariate B-spline neural networks, using the real and imaginary parts of the system input. Following the use of a simple least squares parameter initialization scheme, the Gauss-Newton algorithm is applied for the parameter estimation, which incorporates the De Boor algorithm, including both the B-spline curve and the first-order derivatives recursion. Numerical examples, including a nonlinear high-power amplifier model in communication systems, are used to demonstrate the efficacy of the proposed approaches
The Wiener-Hopf solution of the isotropic penetrable wedge problem: diffraction and total field
Full text linkThe diffraction of an incident plane wave by an isotropic penetrable wedge is studied using generalized Wiener-Hopf equations, and the solution is obtained using analytical and numerical-analytical approaches that reduce the Wiener-Hopf factorization to Fredholm integral equations of second kind. Mathematical aspects are described in a unified and consistent theory for angular region problems. The formulation is presented in the general case of skew incidence and several numerical tests at normal incidence are reported to validate the new technique. The solutions consider engineering applications in terms of GTD/UTD diffraction coefficients and total field
Der Wiener Männergesangverein. Chronik der Jahre 1843 bis 1893 aus anlass fünfzigjährigen Jubelfeier des Vereines, und im Auftrage desselben verfasst,
No full text"Dr. August Schmidt, Gründer des Wiener Männergesang-Vereomes (Selbstbiographie)": p. [i]-xxxix.Mode of access: Internet
The Wiener-Hopf-Hilbert technique applied to problems in diffraction
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.A number of diffraction problems which have practical applications are examined using the Wiener-Hopf-Hilbert technique. Each problem is formulated as a matrix Wiener-Hopf equation, the solution of which requires the factor~sation of a matrix kernel. Since the determinant of the matrix kernel has poles in the cut plane, the
Wiener-Hopf-Hilbert technique is modified to allow the usual arguments to follow through. In each case an explicit matrix factorisation is carried out and asymptotic
expressions for the field scattered to infinity are obtained. The first problem solved is that of diffraction by a semi-infinite plane with different face impedances. The solution includes the case of an incident surface wave as well as an incident plane wave for an arbitrary angle of incidence. Graphs of the far-field are provided for various values of the half-plane impedance parameters. The second
problem examined is diffraction by a half-plane in a moving fluid. This is solved
without restriction on the impedance parameters of the half-plane and includes both the leading edge and trailing edge situations. The final problem is of radiation from an inductive wave-guide. Expressions are obtained for the field radiated at the waveguide mouth and the field reflected in the duct region.This work is funded by the UK Engineering and Physical Sciences Research Council (EPSRC
Wiener-Hopf solution for impenetrable wedges at skew incidence
Full text linkA new Wiener-Hopf approach for the solution of impenetrable wedges at skew incidence is presented. Mathematical aspects are described in a unified and consistent theory for angular region problems. Solutions are obtained using analytical and numerical-analytical approaches. Several numerical tests from the scientific literature validate the new technique, and new solutions for anisotropic surface impedance wedges are solved at skew incidence. The solutions are presented considering the geometrical and uniform theory of diffraction coefficients, total fields, and possible surface wave contribution
p-Wiener intervals and p-Wiener free intervals
No full textA positive integer n is said to be Wiener graphical, if there exists a graph G with Wiener index n. In this paper, we prove that any positive integer n(≠ 2,5) is Wiener graphical. For any positive integer p, an interval [a,b] is said to be a p-Wiener interval if for each positive integer n ∈ [a,b] there exists a graph G on p vertices such that W(G) = n. For any positive integer p, an interval [a,b] is said to be p-Wiener free interval (p-hyper-Wiener free interval) if there exist no graph G on p vertices with a ≤ W(G) ≤ b (a ≤ WW(G) ≤ b). In this paper, we determine some p-Wiener intervals and p-Wiener free intervals for some fixed positive integer p
Georg Wiener Collection. 1933-1957 Bulk: 1930s
No full textThe collection comprises 10 folders containing the original Georg Wiener collection at the beginning, followed by the collection formerly entitled “Oppeln Jewish Community”. The contents are divided into manuscripts, correspondence and community registers. Correspondence folders are arranged alphabetically. Manuscripts are arranged chronologically, where applicable.The manuscripts contain very detailed and comprehensive information regarding the history of the Oppeln Jewish community. Most of the shorter ones are handwritten in old German script, the longer ones are typed. Sometimes there are duplicates and drafts.The correspondence folders include letters between former members of the Oppeln community (post-war) or descendents of members searching for community records (1930s). These will be useful for individuals doing genealogy research as they often contain detailed information regarding a specific family. One letter to Wiener’s brother contains a partial family tree.There are several folders containing typed copies of the Oppeln and Krappitz Jewish community registers. These charts contain dates for births, marriages and deaths of community members from the late 1700s to the mid/late 1800s. Wiener typed them up from the originals in the mid 1930s. They will be very useful for individuals who know their ancestors are from Oppeln or the surrounding area.The following individuals are mentioned in this collection:Baeck, Leo ; Brilling, Bernhard ; Czellitzer, Arthur, 1871-1943 ; de Modena, Leon ; Ehrlich, Paul ; Eisenstadt ; Eliason, M. ; Ephraim, Else ; Fettmilch, Vincent ; Gumpel, Elly ; Guttentag ; Guttmann, Julius ; Jacobsohn, Jacob ; Kassel, Fritz ; Kassel, Otto ; Kassel, Walter V. ; Katscher ; Knoche, Gerd ; Kutzner, P. ; Leobschuetz ; Lippold (Muenzmeister) ; Montefiore, Moses ; Nothmann, Berthold ; Pasha, Emir ; Pinkus, Hans H. ; Schuefftan ; Wachsmann, Oskar ; Weigel, Dr. ; Wiener Family (Oppeln) ; Wiener, Georg ; Wiener, RobertThe following communities are mentioned in this collection:Baldenburg ; Beuthen ; Carlsruhe (Upper Silesia) ; Cosel ; Gleiwitz ; Krappitz Krapkowice ; Konstadt (Upper Silesia) ; Kreuzburg (Upper Silesia) ; Landsberg (Upper Silesia) ; Langendorf ; Oberglogau ; Oppeln ; Peiskretscham ; Potschen ; Ratibor ; Rosenberg (Upper Silesia) ; Strehlitz ; TostThe collection does not contain any precise biographical information regarding Georg Wiener. It may be assumed he was born in the late 19th century. Whether he was related to the Oppeln reformist Rabbi Adolph Wiener (1811-1895) is unclear, but possible. He does write about being descended from Menachem Man, high Rabbi of Vienna at the time of the expulsion of 1670, and Rabbi Itzchak Hakadosch (the former’s son-in-law), martyred in Krakow in prior to that. Wiener was very active in the Oppeln Jewish community, writing articles for the newspaper on community history and actively researching questions of genealogy for members of the community and/or their descendents. He escaped at some point in time during the Second World War to Bolivia. The means and date of escape, date of birth and death are all unknown or in any case, not to be found in the collection.Finding aid available onlineSudan ; Maranos ; Latin America ; East European Jews in Germany ; Blood accusation ; Prague ; Upper Silesia ; Breslau ; Veterans organizations ; Rural Life ; Vital statistics ; Education ; Blood accusationdigitize
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