207 research outputs found
Using Cumulant Analysis For Entropic Complexity Measures
A simplified approach based on the cumulant analysis of the Shannon entropy is proposed for measuring complexity. We report the result of such analysis for some generic problems (mixing r − component ideal
gas, the simplest geometric ornament, Schrödinger's cat states, and the logistic map). We argue that the new measures have benefits compared to the currently practiced measures in the Shiner-Davison-Landsberg and Lopes-Ruiz-Mancini-Calbet approaches
Modeling Off-the-Shelf Pan/Tilt Cameras for Active Vision Systems
There are many existing multicamera systems that perform object identification and track ing. Some applications include but are not limited to security surveillance and smart rooms. Yet there is still much work to be done in improving such systems to achieve a high level of automation while obtaining reasonable performance. Thus far design and implementation of these systems has been done using heuristic methods, primarily due to the complexity of the problem. Most importantiy, the performance of these systems is assessed by evaluating subjective quantities. The goal of this work is to take the first step in structured analysis and design of multicamera systems, that is, to introduce a model of a single camera with asso ciated image processing algorithms capable of tracking a target. A single camera model is developed such that it could be easily used as a building block for a multicamera system
Entanglement Measures for Single- and Multi-Reference Correlation Effects
Electron correlation effects are essential for an accurate ab initio
description of molecules. A quantitative a priori knowledge of the single- or
multi-reference nature of electronic structures as well as of the dominant
contributions to the correlation energy can facilitate the decision regarding
the optimum quantum chemical method of choice. We propose concepts from quantum
information theory as orbital entanglement measures that allow us to evaluate
the single- and multi-reference character of any molecular structure in a given
orbital basis set. By studying these measures we can detect possible artifacts
of small active spaces.Comment: 14 pages, 4 figure
Charge separation: From the topology of molecular electronic transitions to the dye/semiconductor interfacial energetics and kinetics
Charge separation properties, that is the ability of a chromophore, or a
chromophore/semiconductor interface, to separate charges upon light absorption,
are crucial characteristics for an efficient photovoltaic device. Starting from
this concept, we devote the first part of this book chapter to the topological
analysis of molecular electronic transitions induced by photon capture. Such
analysis can be either qualitative or quantitative, and is presented here in
the framework of the reduced density matrix theory applied to single-reference,
multiconfigurational excited states. The qualitative strategies are separated
into density-based and wave function-based approaches, while the quantitative
methods reported here for analysing the photoinduced charge transfer nature are
either fragment-based, global or statistical. In the second part of this
chapter we extend the analysis to dye-sensitized metal oxide surface models,
discussing interfacial charge separation, energetics and electron injection
kinetics from the dye excited state to the semiconductor conduction band
states
Spin Waves and Spin Currents in Magnon-Phonon Composite Resonator Induced by Acoustic Waves of Various Polarizations
In this work, we present the results of a systematic experimental study of
linear and parametric spin wave resonant excitation accompanied by spin
currents (spin pumping) in a multifrequency composite bulk acoustic wave
resonator with a ZnO-YIG-GGG-YIG/Pt structure. The features of magnetic
dynamics excitation in YIG films due to magnetoelastic coupling with acoustic
thickness modes of various polarizations are studied. Acoustic spin waves and
spin pumping are detected by simultaneous frequency-field mapping of the
inverse spin Hall effect voltage and the resonant frequencies of thickness
extensional modes. In the parametric range of frequencies and fields, acoustic
spin pumping induced by both shear and longitudinal polarization modes was
observed. Linear acoustic spin waves are excited only by shear thickness
extensional modes because longitudinal acoustic waves do not couple with the
magnetic subsystem in linear regime
Evaluation of the quasi correlated tight-binding (QCTB) model for describing polyradical character in polycyclic hydrocarbons
We present a verification and significant algorithmic improvement of the quasi-correlation tightbinding (QCTB) scheme (a H¨uckel-Hubbard-type model mimicking electron correlation) for describing
effectively unpaired electrons in the spirit of Head-Gordon’s approach [M. Head-Gordon, Chem. Phys. Lett. 380, 488 (2003)]. For comparison purposes, results based on the high-level ab initio multireference averaged quadratic coupled cluster method previously computed in our works are invoked. In doing so, typical polyaromatic hydrocarbons (polyacenes, periacenes, zethrenes, and the
Clar goblet) are studied. The evaluation shows that the QCTB H¨uckel-like scheme extended for electron correlation effects provides a qualitatively and in several cases also quantitatively good picture of the unpairing electrons in formally closed-shell electronic systems. Additionally, fairly large nanographene systems of triangulene structure (C426) and a perforated nanoribbon (C8860) have been treated at QCTB level. Two analytical model problems in the framework of QCTB prove the ability of this approximation to give a correct description of natural orbital occupancy spectra. For the studied QCTB scheme, an efficient algorithm is elaborated, and large-scale calculations of radical characteristics for nanographene networks with thousands of carbon atoms are possible
System model for informing municipal authorities about environmental pollution and tracking environmental
The paper presents system model designed that can be used to inform municipal authorities about environmental pollution and can track the elimination of environmental problems. The relevance of developing this system is due to the need to improve the quality of monitoring the environmental situation and the speed of response to emerging threats. In the context of increasing environmental challenges, such as air, water and soil pollution, the implementation of automated solutions is becoming important for the effective management of environmental risks. The system includes several key components, such as a user interface, controllers, an application logic module and a database access module. These elements ensure effective interaction between users and operators. An important functionality of the system is the ability to track the status and stages of processing requests, which helps to increase transparency and citizens’ trust in municipal authorities. Also, the system includes a module for collecting and processing statistics on incidents, which allows for quick data analysis and identification of trends in environmental pollution
Graphoepitaxial growth of CeO2 thin films on tilted-axes NdGaO3 substrates by pulsed laser deposition
CeO2 thin films were grown on NdGaO3 tilted-axes substrates by pulsed laser deposition (PLD) showing three-dimensional graphoepitaxial (3DGE) growth in the whole studied range of substrate tilt angles γ = 5-27º. Deviations from the tangent dependence can be divided into a systematic negative part and local deviations near certain film tilt angles. The systematic deviation may be explained as the effect of completely-strained coherent growth of the bottom layers of CeO2 film. Minimization of the surface energy near the small-index crystallographic planes (012) and (013) may account for the local deviations from the calculated dependence. The width of the rocking curve and the lattice constant variation for the 3DGE CeO2 films increase almost linearly with the substrate tilt angle until 19º and decrease for higher γ.
At different deposition rates the 3DGE CeO2 film exhibits three possible structures: (i) relaxed completely oxygenated films at very low deposition rate, (ii) completely strained well-oxygenated films at moderate deposition rates, and (iii) oxygen-deficient films consisting of two layers at high deposition rates. The deviations of orientation of the film from the 3DGE formula are set by the lattice constant c in the direction normal to the (110) SICP of the substrate, which, in turn, depends on oxygen deficiency and the level of strain, introduced into the film by lattice mismatch with the substrate.publishe
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