Search results for "database."
showing 10 items of 2119 documents
X-ray diffraction, optical birefringence, and87Rb nuclear magnetic resonance spectroscopy of the paraelectric and antiferroelectric phases of Rb3DxH1…
2002
The antiferroelectric (AFE) phase transition of Rb3DxH1-x(SO4)2 was studied using x-ray diffraction, optical birefringence, and nuclear magnetic resonance. The orientation dependence of the resonance lines deduced from the quadrupole-perturbed 87Rb nuclear magnetic resonance of Rb3D(SO4)2 single crystals indicates slight deviations from the monoclinic symmetry in the paraelectric and the AFE phases. The dynamical critical exponents as deduced from measurements of the spin-lattice relaxation times depend on the deuteron concentration. Additionally, we have carried out x-ray single-crystal diffraction as well as optical birefringence measurements and find clear evidence for a structural phase…
Pre-service teachers’ experiences with a digital examination design: The inter-relation between continuity and change in an institutional context
2019
AbstractThis article reports a study of a full-scale digital examination in a five-year master program of teacher education in Norway. The innovative design involves observing a video case based on an authentic classroom situation and analysing the case in light of educational theory and subject content knowledge. All parts of this format are to be solved on a computer with Internet access. The study is centred on the pre-service teachers’ experiences of this open-ended and unfamiliar testing format. More specifically, the intention has been to analyse (a) what kinds of preparations they engaged in; (b) how they solved tasks during the examination; (c) their reflections on this mode of exam…
Insights into the compositional evolution of crustal magmatic systems from coupled petrological-geodynamical models
2020
Funding was provided by the VAMOS Research Center, University of Mainz (Germany) and by the ERC Consolidator Grant MAGMA (project #771143). The evolution of crustal magmatic systems is incompletely understood, as most studies are limited either by their temporal or spatial resolution. Exposed plutonic rocks represent the final stage of a long-term evolution punctuated by several magmatic events with different chemistry and generated under different mechanical conditions. Although the final state can be easily described, the nature of each magmatic pulse is more difficult to retrieve. This study presents a new method to investigate the compositional evolution of plutonic systems while consid…
Testing a theoretically-based overland flow resistance law by Emmett’s database
2021
Abstract The main aim of this paper was to test a recently theoretically deduced flow resistance equation, based on a power-velocity profile, using a wide database of available measurements carried out in laboratory and field experimental runs with overland flow under simulated rainfall. In comparison with previous calibrations and validations of this theoretically deduced flow resistance equation, the used database by Emmett is characterized by a wide range of rainfall intensities (from 79.2 to 303.5 mm h−1 for laboratory runs and from 178.3 to 215.9 mm h−1 for field investigations) and bed slopes (from 0.33 to 17% for laboratory runs and from 2.9 to 33.2% for field investigations). For th…
Location theories and business location decision: A micro-spatial investigation of a nonmetropolitan area in Canada
2016
This paper draws on location theories to statistically identify the relationship between the location of individual business establishments and the characterization of their local economic environment. Taking a micro-spatial perspective, the paper develops indicators from distance-based measures (DBM) to serve as independent variables in a discrete choice model (DCM). Using a 2006 database of individual business establishments in the Lower-St-Lawrence region—a coherent, nonmetropolitan subsystem of cities in the province of Québec, Canada—we provide an empirical analysis of the determinants of individual establishments’ location decisions in relation to their main economic activity within a…
A function whose graph has positive doubling measure
2014
We show that a doubling measure on the plane can give positive measure to the graph of a continuous function. This answers a question by Wang, Wen and Wen. Moreover we show that the doubling constant of the measure can be chosen to be arbitrarily close to the doubling constant of the Lebesgue measure.
Capabilities of Ultrametric Automata with One, Two, and Three States
2016
Ultrametric automata use p-adic numbers to describe the random branching of the process of computation. Previous research has shown that ultrametric automata can have a significant decrease in computing complexity. In this paper we consider the languages that can be recognized by one-way ultrametric automata with one, two, and three states. We also show an example of a promise problem that can be solved by ultrametric integral automaton with three states.
New spaces of matrices with operator entries
2019
In this paper, we will consider matrices with entries in the space of operators $\mathcal{B}(H)$, where $H$ is a separable Hilbert space and consider the class of matrices that can be approached in the operator norm by matrices with a finite number of diagonals. We will use the Schur product with Toeplitz matrices generated by summability kernels to describe such a class and show that in the case of Toeplitz matrices it can be identified with the space of continuous functions with values in $\mathcal B(H)$. We shall also introduce matriceal versions with operator entries of classical spaces of holomorphic functions such as $H^\infty(\mathbb{D})$ and $A(\mathbb{D})$ when dealing with upper t…
The Natural Order-Generic Collapse for ω-Representable Databases over the Rational and the Real Ordered Group
2001
We consider order-generic queries, i.e., queries which commute with every order-preserving automorphism of a structure's universe. It is well-known that first-order logic has the natural order-generic collapse over the rational and the real ordered group for the class of dense order constraint databases (also known as finitely representable databases). I.e., on this class of databases over 〈Q, <〉 or 〈R, <〉, addition does not add to the expressive power of first-order logic for defining order-generic queries. In the present paper we develop a natural generalization of the notion of finitely representable databases, where an arbitrary (i.e. possibly infinite) number of regions is allowed. We …
Incremental termination proofs and the length of derivations
1991
Incremental termination proofs, a concept similar to termination proofs by quasi-commuting orderings, are investigated. In particular, we show how an incremental termination proof for a term rewriting system T can be used to derive upper bounds on the length of derivations in T. A number of examples show that our results can be applied to yield (sharp) low-degree polynomial complexity bounds.