71 research outputs found
SPECTRA OF PtC AND RhC
No full textAuthor Institution: Institute of Physics, Vanadisv\""agen 9, University of StockholmIn a King furnace we have obtained the molecules PtC and RhC in the gaseous phase. The absorption spectra of these molecules were taken in a large concave grating spectrograph. The isotope splitting in the Pt-molecule confirms that the molecule must be attributed to PtC. The Rh spectrum was obtained under the same experimental conditions. This fact, together with the magnitudes of the molecular constants, makes it very unlikely that the absorber is anything other than RhC. Rotational analysis has been carried out for both molecules. In PtC two systems have been analysed, one and one , with the lower state in common. In RhC four states have been studied. Three of them are states, one is a state. The lowest state is a state. The two excited states strongly interact with each other. The following molecular constants in have been derived for the lowest states. $\begin{array}{llll}&Ptc &RhC\\\omega_{o}&1051.18 &1049.87\\ \omega_{o}X_{v} & 4.87 & 4.94\\ B_{o}&0.5303 &0.6027\\\alpha_{o}&0.0032 &0.00396\end{array}
Controle de formação com seguimento de referência para grupos de veículos autônomos utilizando consenso e RHC
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2014O movimento em formação e o seguimento de uma trajetória de referência são alguns dos problemas que tipicamente compõem uma tarefa para um grupo de veículos autônomos que cooperam entre si. Neste trabalho, ambos os problemas são abordados e uma solução é proposta utilizando-se RHC (Receding Horizon Control) e o conceito de estruturas virtuais de forma descentralizada. O método proposto consiste em um problema de otimização quadrática que realiza o consenso a respeito do centro da formação e gera uma trajetória para que o robô que a executa alcance sua posição desejada. Para o controle de veículos com restrições não-holonômicas, um controle de baixo nível é utilizado para fazer o robô seguir a trajetória gerada. Para a avaliação e teste do método proposto, um simulador, capaz de interagir com robôs reais através do ROS (Robot Operating System), foi desenvolvido e dois conjuntos de testes foram feitos. O primeiro consistiu de simulações com diferentes valores para os parâmetros da função objetivo, de forma a avaliar a eficácia do método e sua dependência nos parâmetros. O segundo consistiu de testes de realidade aumentada, em que veículos reais e virtuais integravam o grupo. Os resultados são analisados e comprovam a eficácia do método, mas ainda são necessários estudos sobre os critérios de convergência e estabilidade.Abstract: Moving in formation and tracking a reference trajectory are common problems when composing tasks for a group of cooperating autonomous vehicles. In this work, both problems are treated and a solution is proposed using RHC (Receding Horizon Control) and the concept of virtual structures in a decentralized manner. The proposed method consists of a quadratic optimization problem which is responsible for the consensus about the position of the formation center and the trajectory generation so that the robot can get to its desired position. For the control of non-holonomic vehicles, a low-level controller scheme is used to make the robot follow the generated trajectory. For the evaluation of the proposed method, a simulator capable of interaction with real robots through the use of ROS (Robot Operating System) was developed and two sets of trials were done. The first consisted of simulations with differing values of the objective function's parameters, so as to assess the effectiveness of the method and its dependency on the parameters' values. the second set consisted of tests with augmented reality, in which real and virtual robots integrated the group. The results are analised and show the effectiveness of the method, but the convergence and stability criteria need more study
Evidence for erbium-erbium energy migration in erbium(III) bis(perfluoro-p-tolyl)phosphinate
No full textCopyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Applied Physics Letters 92, 103303 (2008) and may be found at
A well-separated pairs decomposition algorithm for k-d trees implemented on multi-core architectures
No full textContent from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Variations of k-d trees represent a fundamental data structure used in Computational Geometry with numerous applications in science. For example particle track tting in the software of the LHC experiments, and in simulations of N-body systems in the study of dynamics of interacting galaxies, particle beam physics, and molecular dynamics in biochemistry. The many-body tree methods devised by Barnes and Hutt in the 1980s and the Fast Multipole Method introduced in 1987 by Greengard and Rokhlin use variants of k-d trees to reduce the computation time upper bounds to O(n log n) and even O(n) from O(n2). We present an algorithm that uses the principle of well-separated pairs decomposition to always produce compressed trees in O(n log n) work. We present and evaluate parallel implementations for the algorithm that can take advantage of multi-core architectures.The Science and Technology Facilities Council, UK
Reproductive Health Equity: One Key Question© for Women in Recovery
No full textabstract: Women in recovery from substance use disorders (SUD) face significant barriers to achieving reproductive well-being (RWB) and disproportionately experience unintended pregnancy. Unintended pregnancy can have serious consequences in this population. Equity-informed approaches promote the integration of reproductive health care (RHC) with recovery programs to improve both access to and quality of RHC. Arizona’s largest SUD recovery program, Crossroads, Inc. recently opened an on-site, integrated primary clinic offering RHC. A one-month pilot demonstration of One Key Question (OKQ), a pregnancy desire screening tool, was implemented with fidelity at Crossroads to identify clients with RHC needs and offer care. IRB exempt status was obtained through Arizona State University. All female-bodied clients aged 18-49 were screened following routine admission assessments. The Institute for Healthcare Improvement Triple Aim model based on Self-Determination Theory and Motivational Interviewing was used to prioritize client autonomy. The client experience of care was measured using an adapted Interpersonal Quality of Family Planning scale. The magnitude of needs and desires were summarized with descriptive statistics. Sixty-three clients were screened with OKQ. Needs were identified in 97% of clients. Of those clients, 98% accepted referrals. Ninety percent of items measuring the client experience of care were rated as “excellent.” OKQ provided an efficient structure for person-centered screening and referral conversations to integrate RHC in a large SUD recovery program with excellent care experiences reported by clients
Comparison of two-dimensional binned data distributions using the energy test
No full textFor the purposes of monitoring HEP experiments, comparison is often made between regularly acquired histograms of data and reference histograms which represent the ideal state of the equipment. With the larger experiments now starting up, there is a need for automation of this task since the volume of comparisons would overwhelm human operators. However, the two-dimensional histogram comparison tools currently available in ROOT have noticeable shortcomings. We present a new comparison test for 2D histograms, based on the Energy Test of Aslan and Zech, which provides more decisive discrimination between histograms of data coming from different distributions
Computationally efficient algorithms for the two-dimensional Kolmogorov-Smirnov test
No full textGoodness-of-fit statistics measure the compatibility of random samples against some theoretical or reference probability distribution function. The classical one-dimensional Kolmogorov-Smirnov test is a non-parametric statistic for comparing two empirical distributions which defines the largest absolute difference between the two cumulative distribution functions as a measure of disagreement. Adapting this test to more than one dimension is a challenge because there are 2^d-1 independent ways of ordering a cumulative distribution function in d dimensions. We discuss Peacock's version of the Kolmogorov-Smirnov test for two-dimensional data sets which computes the differences between cumulative distribution functions in 4n^2 quadrants. We also examine Fasano and Franceschini's variation of Peacock's test, Cooke's algorithm for Peacock's test, and ROOT's version of the two-dimensional Kolmogorov-Smirnov test. We establish a lower-bound limit on the work for computing Peacock's test of
Omega(n^2.lg(n)), introducing optimal algorithms for both this and Fasano and Franceschini's test, and show that Cooke's algorithm is not a faithful implementation of Peacock's test. We also discuss and evaluate parallel algorithms for Peacock's test
The two-dimensional Kolmogorov-Smirnov test
No full textGoodness-of-fit statistics measure the compatibility of random samples against some theoretical
probability distribution function. The classical one-dimensional Kolmogorov-Smirnov test is a
non-parametric statistic for comparing two empirical distributions which defines the largest absolute
difference between the two cumulative distribution functions as a measure of disagreement.
Adapting this test to more than one dimension is a challenge because there are 2d −1 independent
ways of defining a cumulative distribution function when d dimensions are involved. In this paper
three variations on the Kolmogorov-Smirnov test for multi-dimensional data sets are surveyed:
Peacock’s test [1] that computes in O(n3); Fasano and Franceschini’s test [2] that computes in
O(n2); Cooke’s test that computes in O(n2).
We prove that Cooke’s algorithm runs in O(n2), contrary to his claims that it runs in O(nlgn).
We also compare these algorithms with ROOT’s version of the Kolmogorov-Smirnov test
An efficient ant colony system based on receding horizon control for the aircraft arrival sequencing and scheduling problem
No full textThe aircraft arrival sequencing and scheduling (ASS) problem is a salient problem in air traffic control (ATC), which proves to be nondeterministic polynomial (NP) hard. This paper formulates the ASS problem in the form of a permutation problem and proposes a new solution framework that makes the first attempt at using an ant colony system (ACS) algorithm based on the receding horizon control (RHC) to solve it. The resultant RHC-improved ACS algorithm for the ASS problem (termed the RHC-ACS-ASS algorithm) is robust, effective, and efficient, not only due to that the ACS algorithm has a strong global search ability and has been proven to be suitable for these kinds of NP-hard problems but also due to that the RHC technique can divide the problem with receding time windows to reduce the computational burden and enhance the solution's quality. The RHC-ACS-ASS algorithm is extensively tested on the cases from the literatures and the cases randomly generated. Comprehensive investigations are also made for the evaluation of the influences of ACS and RHC parameters on the performance of the algorithm. Moreover, the proposed algorithm is further enhanced by using a two-opt exchange heuristic local search. Experimental results verify that the proposed RHC-ACS-ASS algorithm generally outperforms ordinary ACS without using the RHC technique and genetic algorithms (GAs) in solving the ASS problems and offers high robustness, effectiveness, and efficienc
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