996 resultados para OCE– (CE–) Regular Spaces
Resumo:
∗ This work was partially supported by the National Foundation for Scientific Researches at the Bulgarian Ministry of Education and Science under contract no. MM-427/94.
Resumo:
We prove that, for every countable ordinal α ≥ 3, there exists countable completely regular spaces Xα and Yα such that the spaces Cp (Xα ) and Cp (Yα ) are borelian of class exactly Mα , but are not homeomorphic.
Resumo:
We consider canonical systems with singular left endpoints, and discuss the concept of a scalar spectral measure and the corresponding generalized Fourier transform associated with a canonical system with a singular left endpoint. We use the framework of de Branges’ theory of Hilbert spaces of entire functions to study the correspondence between chains of non-regular de Branges spaces, canonical systems with singular left endpoints, and spectral measures.
We find sufficient integrability conditions on a Hamiltonian H which ensure the existence of a chain of de Branges functions in the first generalized Pólya class with Hamiltonian H. This result generalizes de Branges’ Theorem 41, which showed the sufficiency of stronger integrability conditions on H for the existence of a chain in the Pólya class. We show the conditions that de Branges came up with are also necessary. In the case of Krein’s strings, namely when the Hamiltonian is diagonal, we show our proposed conditions are also necessary.
We also investigate the asymptotic conditions on chains of de Branges functions as t approaches its left endpoint. We show there is a one-to-one correspondence between chains of de Branges functions satisfying certain asymptotic conditions and chains in the Pólya class. In the case of Krein’s strings, we also establish the one-to-one correspondence between chains satisfying certain asymptotic conditions and chains in the generalized Pólya class.
Resumo:
2000 Mathematics Subject Classification: Primary 46E15, 54C55; Secondary 28B20.
Resumo:
This thesis presents an empirical study of the effects of topology on cellular automata rule spaces. The classical definition of a cellular automaton is restricted to that of a regular lattice, often with periodic boundary conditions. This definition is extended to allow for arbitrary topologies. The dynamics of cellular automata within the triangular tessellation were analysed when transformed to 2-manifolds of topological genus 0, genus 1 and genus 2. Cellular automata dynamics were analysed from a statistical mechanics perspective. The sample sizes required to obtain accurate entropy calculations were determined by an entropy error analysis which observed the error in the computed entropy against increasing sample sizes. Each cellular automata rule space was sampled repeatedly and the selected cellular automata were simulated over many thousands of trials for each topology. This resulted in an entropy distribution for each rule space. The computed entropy distributions are indicative of the cellular automata dynamical class distribution. Through the comparison of these dynamical class distributions using the E-statistic, it was identified that such topological changes cause these distributions to alter. This is a significant result which implies that both global structure and local dynamics play a important role in defining long term behaviour of cellular automata.
Resumo:
O presente estudo abordou o Projeto Ético-Político do Serviço Social brasileiro, considerando o seu possível tensionamento no âmbito da política de assistência social, na região Centro Sul/Vale do Salgado no estado do Ceará. Portanto, através do nosso estudo, pretendeu-se analisar as possibilidades e os limites de materialização do Projeto Ético-Político Serviço Social brasileiro na política de assistência social, em tal região. Optamos por essa análise por considerarmos imprescindível apreender as tensões impostas a esse Projeto no cotidiano de trabalho profissional do (a) assistente social. E, para tanto, foi imprescindível analisarmos a atual configuração da assistência social, partindo das diretrizes da Política Nacional de Assistência Social e confrontando-as com o processo de municipalização desta política no campo pesquisado. Avaliamos a relevância do presente estudo em decorrência do atual processo de expansão e centralidade da política de assistência social, no cenário brasileiro, como estratégia de alívio à miséria e à pobreza. Tal movimento se realiza expressando um duplo movimento: a implementação do Sistema Único de Assistência Social e a prevalência dos Programas de Transferência de Renda. Esse contexto tem ampliado, sobremaneira, a requisição aos assistentes sociais, que vêm ocupando, majoritariamente, tais espaços sócio-ocupacionais. Entretanto, essa inserção tem se realizado sob condições e relações de trabalho precarizadas, o que pode implicar em uma possível intensificação do tensionamento do Projeto Ético-Político do Serviço Social brasileiro. A pesquisa foi realizada por meio de entrevistas com os (as) profissionais atuantes nos Centros de Referência da Assistência Social (CRASs) e Centros de Referência Especializado da Assistência Social (CREAs), em sete municípios da região selecionada como campo empírico. Os dados analisados também são resultados das visitas institucionais e observações de campo que realizamos no espaço sócio-ocupacional dos (as) profissionais entrevistados (as). A presente pesquisa está assentada no materialismo histórico e dialético, método de apreensão do real, originalmente elaborado por Marx.
Resumo:
The contribution described in this paper is an algorithm for learning nonlinear, reference tracking, control policies given no prior knowledge of the dynamical system and limited interaction with the system through the learning process. Concepts from the field of reinforcement learning, Bayesian statistics and classical control have been brought together in the formulation of this algorithm which can be viewed as a form of indirect self tuning regulator. On the task of reference tracking using a simulated inverted pendulum it was shown to yield generally improved performance on the best controller derived from the standard linear quadratic method using only 30 s of total interaction with the system. Finally, the algorithm was shown to work on the simulated double pendulum proving its ability to solve nontrivial control tasks. © 2011 IEEE.
Resumo:
A novel electroluminescence oxide phosphor (Gd2O3-Ga2O3):Ce has been prepared by electron beam evaporation. The emission peaks of photoluminescence lie at 390nm and a shoulder at 440nm. However, the electroluminescence of the (Gd2O3-Ga2O3):Ce thin film have four emission peaks at 358nm, 390nm, 439nm and 510nm, respectively. The optical absorption of (Gd2O3-Ga2O3):Ce thin film and the photoluminescence of composite materials with various ratios of Ga2O3/(Gd2O3+Ga2O3) have also been described to investigate the origin of emission of photoluminescence and electroluminescence.
Resumo:
The crystallographic and intrinsic magnetic properties of hydride R3Fe29-xTxHy (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) have been investigated. The lattice constants and the unit cell volume of R3Fe29-xTxHy decrease with increasing R atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Regular anisotropic expansions, mainly along the a- and b-axis rather than along the c-axis, are observed for all the compounds upon hydrogenation. Hydrogenation leads to an increase in Curie temperature. First-order magnetization processes (FOMP) occur in magnetic fields of around 1.5 T and 4.0 T at 4.2 K for Nd3Fe24.5Cr4.5H5.0 and Tb(3)Fc(27.0)Cr(2.0)H(2.8), and around 1.4 T at room temperature for Gd3Fe28.0Cr1.0H4.2 Abnormal crystallographic and magnetic properties of Ce3Fe29-xTxHy suggest that the Ce ion is non-triply ionized.
Resumo:
A systematic study of the phase formation, structure and magnetic properties of the R3Fe29-xTx compounds (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) has been performed upon hydrogenation. The lattice constants and the unit cell volume of R3Fe29-xTxHy decrease with increasing R atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Regular anisotropic expansions mainly along the a- and b-axis rather than along the c-axis are observed for all of the compounds upon hydrogenation. Hydrogenation leads to an increase in the Curie temperature and a corresponding increase in the saturation magnetization at room temperature for each compound. First order magnetization processes (FOMP) occur in the external magnetic fields for Nd3Fe24.5Cr4.5H5.0, Tb3Fe27.0Cr2.0H2.8, and Gd3Fe28.0Cr1.0H4.2 compounds.
Resumo:
A systematic investigation of crystallographic and intrinsic magnetic properties of the hydrides R3Fe29 - xVxHy (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) has been performed in this work. The lattice constants a, b, and c and the unit cell volume of R3Fe29 - xVxHy decrease with increasing rare-earth atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Hydrogenation results in regular anisotropic expansions along the a-, b-, and c-axes in this series of hydrides. Abnormal crystallographic and magnetic properties of Ce3Fe27.5V1.5H6.5, like Ce3Fe27.5V1.5, suggest that the Ce ion is non-triply ionized. Hydrogenation leads to the increase in both Curie temperature for all the compounds and in the saturation magnetization at 4.2 K and RT for R3Fe29 - xVx with R = Y, Ce, Nd, Sm, Gd, and Dy, except for Tb. Hydrogenation also leads to a decrease in the anisotropy field at 4.2 K and RT for R3Fe29 - xVx with R = Y, Ce, Nd, Gd, Tb, and Dy, except for Sm. The Ce3Fe27.5V1.5 and Gd3Fe28.4V0.6 show the larger storage of hydrogen with y = 6.5 and 6.9 in these hydrides. (C) 1998 Elsevier Science B.V. All rights reserved.
Resumo:
The crystallographic and intrinsic magnetic properties of hydride R3Fe29-xTxHy (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) have been investigated. The lattice constants and the unit cell volume of R3Fe29-xTxHy decrease with increasing R atomic number from Nd to Dy, except for Ce, reflecting the lanthanide contraction. Regular anisotropic expansions, mainly along the a- and b-axis rather than along the c-axis, are observed for all the compounds upon hydrogenation. Hydrogenation leads to an increase in Curie temperature. First-order magnetization processes (FOMP) occur in magnetic fields of around 1.5 T and 4.0 T at 4.2 K for Nd3Fe24.5Cr4.5H5.0 and Tb(3)Fc(27.0)Cr(2.0)H(2.8), and around 1.4 T at room temperature for Gd3Fe28.0Cr1.0H4.2 Abnormal crystallographic and magnetic properties of Ce3Fe29-xTxHy suggest that the Ce ion is non-triply ionized.
Resumo:
Poster pokazuje metody komunikacji z czytelnikiem stosowane w Bibliotece Uniwersyteckiej w Poznaniu w technologii mediów cyfrowych. Cyfrowe narzędzia komunikacji stały się bardzo pomocne, niemal niezbędne w pozyskiwaniu nowych czytelników, podtrzymywaniu i rozwijaniu współpracy w społeczności w sieci Web.2.0, zarówno tej globalnej, jak i lokalnej akademickiej. Strona WWW jako statyczna komunikacyjnie jest wspierana przez fora dyskusyjne, chaty, wideokonferencje, warsztaty informacyjne, które są prowadzone w czasie rzeczywistym. Twórczą siłę relacji społecznych z biblioteką rozwinęły interaktywne serwisy społecznościowe (Facebook) oraz komunikatory internetowe integrowane na platformie Ask a Librarian. Biblioteka stała się Biblioteką 2.0 ukierunkowaną na komunikację z czytelnikiem. Aktywne uczestnictwo i udział czytelników przy tworzeniu zasobów naukowych wdrożyliśmy w projekcie instytucjonalnego repozytorium - Adam Mickiewicz Repository (AMUR). Biblioteka zmienia się dla czytelników i z czytelnikami. Wykorzystywane platformy i serwisy społecznościowe dostarczają unikatowych danych o nowych potrzebach informacyjnych i oczekiwaniach docelowego Patrona 2.0, co skutkuje doskonaleniu usług istniejących i tworzeniu nowych. Biblioteka monitoruje usługi i potrzeby czytelników przez prowadzone badania społeczne. Technologie cyfrowe stosowane w komunikacji sprawiają, iż biblioteka staje się bliższa, bardziej dostępna, aby stać się w rezultacie partnerem dla stałych i nowych czytelników. Biblioteka Uniwersytecka w Poznaniu bierze udział w programach europejskich w zakresie katalogowania i digitalizacji zasobu biblioteki cyfrowej WBC, w zakresie wdrożenia nowych technologii i rozwiązań podnoszących jakość usług bibliotecznych, działalności kulturotwórczej (Poznańska Dyskusyjna Akademia Kominksu, deBiUty) i edukacji informacyjnej. Biblioteka Uniwersytecka w Poznaniu jest członkiem organizacji międzynarodowych: LIBER (Liga Europejskich Bibliotek Naukowych), IAML (Stowarzyszenie Bibliotek Muzycznych, Archiwów i Ośrodków Dokumentacji), CERL - Europejskie Konsorcjum Bibliotek Naukowych.