ELLIPSE FITTING USING FINITE RATE OF INNOVATION PRINCIPLES

We address the problem of parameter estimation of an ellipse from a limited number of samples. We develop a new approach for solving the ellipse fitting problem by showing that the x and y coordinate functions of an ellipse are finite-rate-of-innovation (FRI) signals. Uniform samples of x and y coordinate functions of the ellipse are modeled as a sum of weighted complex exponentials, for which we propose an efficient annihilating filter technique to estimate the ellipse parameters from the samples. The FRI framework allows for estimating the ellipse parameters reliably from partial or incomplete measurements even in the presence of noise. The efficiency and robustness of the proposed method is compared with state-of-art direct method. The experimental results show that the estimated parameters have lesser bias compared with the direct method and the estimation error is reduced by 5-10 dB relative to the direct method.

Towards an exact factorization of the molecular wave function

An exact single-product factorisation of the molecular wave function for the timedependent Schrodinger equation is investigated by using an ansatz involving a phasefactor. By using the Frenkel variational method, we obtain the Schrodinger equations for the electronic and nuclear wave functions. The concept of a potential energy surface (PES) is retained by introducing a modified Hamiltonian as suggested earlier by Cederbaum. The parameter in the phase factor is chosen such that the equations of motion retain the physically appealing Born- Oppenheimer-like form, and is therefore unique.

Ellipse Fitting Using the Finite Rate of Innovation Sampling Principle

Standard approaches for ellipse fitting are based on the minimization of algebraic or geometric distance between the given data and a template ellipse. When the data are noisy and come from a partial ellipse, the state-of-the-art methods tend to produce biased ellipses. We rely on the sampling structure of the underlying signal and show that the x- and y-coordinate functions of an ellipse are finite-rate-of-innovation (FRI) signals, and that their parameters are estimable from partial data. We consider both uniform and nonuniform sampling scenarios in the presence of noise and show that the data can be modeled as a sum of random amplitude-modulated complex exponentials. A low-pass filter is used to suppress noise and approximate the data as a sum of weighted complex exponentials. The annihilating filter used in FRI approaches is applied to estimate the sampling interval in the closed form. We perform experiments on simulated and real data, and assess both objective and subjective performances in comparison with the state-of-the-art ellipse fitting methods. The proposed method produces ellipses with lesser bias. Furthermore, the mean-squared error is lesser by about 2 to 10 dB. We show the applications of ellipse fitting in iris images starting from partial edge contours, and to free-hand ellipses drawn on a touch-screen tablet.

The application of B-P constitutive equations in finite element analysis of high velocity impact

We present in this paper the application of B-P constitutive equations in finite element analysis of high velocity impact. The impact process carries out in so quick time that the heat-conducting can be neglected and meanwhile, the functions of temperature in equations need to be replaced by functions of plastic work. The material constants in the revised equations can be determined by comparison of the one-dimensional calculations with the experiments of Hopkinson bar. It can be seen from the comparison of the calculation with the experiment of a tungsten alloy projectile impacting a three-layer plate that the B-P constitutive equations in that the functions of temperature were replaced by the functions of plastic work can be used to analysis of high velocity impact.

A New Version of Smoothed Point Method to Simulate Linear Elastic Wave Propagation

By using the kernel function of the smoothed particle hydrodynamics (SPH) and modification of statistical volumes of the boundary points and their kernel functions, a new version of smoothed point method is established for simulating elastic waves in solid. With the simplicity of SPH kept, the method is easy to handle stress boundary conditions, especially for the transmitting boundary condition. A result improving by de-convolution is also proposed to achieve high accuracy under a relatively large smooth length. A numerical example is given and compared favorably with the analytical solution.

Funciones ejecutivas y control ejecutivo : una revisión bibliográfica mirando la arquitectura de la mente

El término “funciones ejecutivas” comienza a ser utilizado por Lezak en los 80’. No se trata de un concepto unitario, incluyendo varias funciones cognitivas y autodirigidas que contribuyen a la autorregulación del individuo. Existen varias controversias acerca del constructo “funciones ejecutivas”, entre ellas: la unidad vs diversidad de los procesos cognitivos que implican las funciones ejecutivas, y la naturaleza del control ejecutivo; el presente artículo se focaliza sobre esta última cuestión. Se presentarán dos aproximaciones de acuerdo a distintos modos de explicación de la memoria de trabajo y del control ejecutivo. Finalmente, se propone enfocar el estudio de las funciones ejecutivas desde una visión integrada de la mente, para su mejor comprensión.

Short-surface waves radiated by a partially-immersed 3-dimensional oscillating body

The short-surface waves generated by a 3-D arbitrarily oscillating body floating onwater are discussed. In the far-field off the body, the phase and the amplitude functions ofthe radiated waves are determined by the ray method. An undetermined constant is includ-ed in the amplitude function. From the result of Ref. [1], the near-field boundary layersolution near the body waterline is obtained. The amplitude of this solution depends on thewhole wall shape of the body and the slope at the body waterline on the cross-sections per-pendicular to the waterline. By matching the far-field solution with the near-field bound-ary layer solution, the undetermined constant in the amplitude function of the far-fieldradiated waves is determined. For the special case of a half-submerged sphere which per-forms vertical oscillating motion, the result obtained in this paper is in agreement withthat of Ref. [ 2 ].

Interim report on the progress of an inventory of artesian wells in Florida: leading to the enforcement of sections 370.051 - 370.54, Florida statues

One of the causes of lower artesian pressure, water waste and aquifer contamination is the misuse and insufficient care of artesian wells. In 1953, Senate Bill No. 57, entitled "An Act to Protect and Control the Artesian Waters of the State" (see Appendix) became a law. This law was passed through the efforts exerted by leading members of the Senate and the House of Representatives, who understood the need for a wise and controlled expenditure of our most valuable natural resource. The State Geologist and his authorized representatives were designated by this law to enforce this conservation measure; however, no financial provision was included for the 1953-55 biennium. The proposed program of the Florida Geological Survey for this biennium did not include the funds nor provide any full-time personnel for the enforcement of this statute. As a result, little actual work was accomplished during these two years, although much time was given to planning and discussion of the problem. Realizing that this program could provide additional basic data needed in the analysis of the water-supply problem, the State Geologist sought and was granted by the 1955 Legislature adequate funds with which to activate the first phase of the enforcement of Florida Statute No. 370.051-054. Enumerated below is a summary of the progress made on this investigation as outlined previously: 1. Data have been collected on 967 wildly flowing wells in 22 counties. 2. Chloride determinations have been run on 850 of the 967 wells. 3. Of the 967 wells, 554 have chlorides in excess of the 250 ppm, the upper limit assigned by the State Board of Health for public consumption. 4. Water escapes at the rate of 37, 762 gallons per minute from these 967 wells. This amounts to 54, 377, 280 gallons per day. The investigation is incomplete at this time; therefore, no final conclusions can be reached. However, from data already collected, the following recommendations are proposed: 1. That the present inventory of wildly flowing wells be completed for the entire State. 2. That the current inventory of wildly flowing wells be expanded at the conclusion of the present inventory to include all flowing wells. 3. That a complete statewide inventory program be established and conducted in cooperation with the Ground Water Branchof the U.S. Geological Survey. 4. That the enforcement functions as set down in Sections 370.051/.054, Florida Statutes, be separated from the program to collect water-resource data and that these functions be given to the Water Resources Department, if such is created (to be recommended by the Water Resources Study Commission in a water policy law presented to the 1957 Legislature). 5. That the research phase (well inventory) of the program remain under the direction of the Florida Geological Survey. (PDF contains 204 pages.)

Forward-looking Pairwise Stability in Networks with Externalities

We consider cooperation situations where players have network relations. Networks evolve according to a stationary transition probability matrix and at each moment in time players receive payoffs from a stationary allocation rule. Players discount the future by a common factor. The pair formed by an allocation rule and a transition probability matrix is called a forward-looking network formation scheme if, first, the probability that a link is created is positive if the discounted, expected gains to its two participants are positive, and if, second, the probability that a link is eliminated is positive if the discounted, expected gains to at least one of its two participants are positive. The main result is the existence, for all discount factors and all value functions, of a forward-looking network formation scheme. Furthermore, we can always nd a forward-looking network formation scheme such that (i) the allocation rule is component balanced and (ii) the transition probabilities increase in the di erence in payo s for the corresponding players responsible for the transition. We use this dynamic solution concept to explore the tension between e ciency and stability.

Influence of Coulomb potential for photoionization of H atoms in an elliptically polarized laser field: Velocity gauge versus length gauge

We theoretically study the influence of Coulomb potential for photoionization of hydrogen atoms in an intense laser field with elliptical polarization. The total ionization rates, photoelectron energy spectra, and photoelectron angular distributions are calculated with the Coulomb-Volkov wave functions in the velocity gauge and compared with those calculated in the length gauge as well as those calculated with the Volkov wave functions. By comparing the results obtained by the Coulomb-Volkov and Volkov wave functions, we find that for linear polarization the influence of Coulomb potential is obvious for low-energy photoelectrons, and as the photoelectron energy and/or the laser intensity increase, its influence becomes smaller. This trend, however, is not so clear for the case of elliptical polarization. We also find that the twofold symmetry in the photoelectron angular distributions for elliptical polarization is caused by the cooperation of Coulomb potential and interference of multiple transition channels. About the gauge issue, we show that the difference in the photoelectron angular distributions obtained by the velocity and length gauges becomes rather obvious for elliptical polarization, while the difference is generally smaller for linear polarization.

Towards understanding the mixing characteristics of turbulent buoyant flows

This work proposes a new simulation methodology in which variable density turbulent flows can be studied in the context of a mixing layer with or without the presence of gravity. Specifically, this methodology is developed to probe the nature of non-buoyantly-driven (i.e. isotropically-driven) or buoyantly-driven mixing deep inside a mixing layer. Numerical forcing methods are incorporated into both the velocity and scalar fields, which extends the length of time over which mixing physics can be studied. The simulation framework is designed to allow for independent variation of four non-dimensional parameters, including the Reynolds, Richardson, Atwood, and Schmidt numbers. Additionally, the governing equations are integrated in such a way to allow for the relative magnitude of buoyant energy production and non-buoyant energy production to be varied.

The computational requirements needed to implement the proposed configuration are presented. They are justified in terms of grid resolution, order of accuracy, and transport scheme. Canonical features of turbulent buoyant flows are reproduced as validation of the proposed methodology. These features include the recovery of isotropic Kolmogorov scales under buoyant and non-buoyant conditions, the recovery of anisotropic one-dimensional energy spectra under buoyant conditions, and the preservation of known statistical distributions in the scalar field, as found in other DNS studies.

This simulation methodology is used to perform a parametric study of turbulent buoyant flows to discern the effects of varying the Reynolds, Richardson, and Atwood numbers on the resulting state of mixing. The effects of the Reynolds and Atwood numbers are isolated by looking at two energy dissipation rate conditions under non-buoyant (variable density) and constant density conditions. The effects of Richardson number are isolated by varying the ratio of buoyant energy production to total energy production from zero (non-buoyant) to one (entirely buoyant) under constant Atwood number, Schmidt number, and energy dissipation rate conditions. It is found that the major differences between non-buoyant and buoyant turbulent flows are contained in the transfer spectrum and longitudinal structure functions, while all other metrics are largely similar (e.g. energy spectra, alignment characteristics of the strain-rate tensor). Also, despite the differences noted between fully buoyant and non-buoyant turbulent fields, the scalar field, in all cases, is unchanged by these. The mixing dynamics in the scalar field are found to be insensitive to the source of turbulent kinetic energy production (non-buoyant vs. buoyant).

La envolvente de los edificios como generador de calor y energía eléctrica

[ES]El presente documento analiza las principales funciones que se le exigen actualmente a un sistema constructivo; concretamente, a la envolvente de los edificios. Se plantean inicialmente las causas y necesidades que han derivado en el nuevo concepto de envolvente así como las nuevas funciones que se le son exigibles. Se describen los conceptos relativos a los diferentes sistemas constructivos, a los métodos de ventilación natural y, a continuación, se analizan los criterios de generación fotovoltaica y solar térmica en los edificios, además de la integración de estos sistemas en los edificios. También se analizan los fundamentos sobre materiales de cambio de fase. Todo ello permite presentar los criterios de construcción de edificios ecoeficientes. Asimismo se presentan una serie de soluciones arquitectónicas desde el punto de vista de la eficiencia energética.

The structure of liquid argon as determined by x-ray diffraction

X-ray diffraction measurements and subsequent data analyses have been carried out on liquid argon at five states in the density range of 0.91 to 1.135 gm/cc and temperature range of 127 to 143°K. Duplicate measurements were made on all states. These data yielded radial distribution and direct correlation functions which were then used to compute the pair potential using the Percus-Yevick equation. The potential minima are in the range of -105 to -120°K and appear to substantiate current theoretical estimates of the effective pair potential in the presence of a weak three-body force.

The data analysis procedure used was new and does not distinguish between the coherent and incoherent absorption factors for the cell scattering which were essentially equal. With this simplification, the argon scattering estimate was compared to the gas scattering estimate on the laboratory frame of reference and the two estimates coincided, indicating the data normalized. The argon scattering on the laboratory frame of reference was examined for the existence of the peaks in the structure factor and the existence of an observable third peak was considered doubtful.

Numerical studies of the effect of truncation, normalization, the subsidiary peak phenomenon in the radial distribution function, uncertainties in the low angle data relative to errors in the direct correlation function and the distortion phenomenon are presented.

The distortion phenomenon for this experiment explains why the Mikolaj-Pings argon data yielded pair potential well depths from the Percus-Yevick equation that were too shallow and an apparent slope with respect to density that was too steep compared to theoretical estimates.

The data presented for each measurement are: empty cell and cell plus argon intensity, absorption factors, argon intensity, smoothed argon intensity, smoothed argon intensity corrected for distortion, structure factor, radial distribution function, direct correlation function and the pair potential from the Percus-Yevick equation.

Prevalência de demência e fatores associados ao desempenho cognitivo em idosos clientes de uma operadora de saúde

Com o envelhecimento populacional observa-se um aumento na prevalência de doenças degenerativas como as demências, caracterizadas pela presença de declínio da memória e de outras funções cognitivas, que resulta na incapacidade do indivíduo para realizar suas atividades de vida diária. O presente estudo teve como objetivo descrever a prevalência geral da síndrome demencial e de seus principais subtipos entre idosos, e verificar a associação entre níveis de complexidade da ocupação desenvolvida ao longo da vida com o desempenho cognitivo na velhice. O desenho do estudo foi transversal e conduzido em duas etapas: rastreio de comprometimento cognitivo e avaliação diagnóstica. Foi utilizada a base de dados da Rede FIBRARJ, que avaliou clientes idosos (>65 anos) de uma operadora privada de saúde, residentes na zona norte do município do Rio de Janeiro. A seleção desta amostra foi feita por meio de amostragem aleatória inversa em cada estrato de sexo e faixa etária. Para cumprir o objetivo de estimar a prevalência de demência, foram avaliados 683 idosos. Para verificar a associação do desempenho cognitivo com a ocupação, foram incluídos 666 indivíduos, que haviam respondido ao instrumento de rastreio cognitivo e aceitaram responder ao questionários sobre ocupação. O diagnóstico de síndrome demencial foi obtido segundo critérios do DSM-IV; as variáveis gênero, idade, escolaridade, renda, situação conjugal e ocupação foram coletadas por entrevistas. Um total de 115 indivíduos foram diagnosticados com síndrome demencial, resultando em uma prevalência de 16,9% (IC 95%=14,4-19,8). Na regressão logística múltipla, idade e escolaridade mostraram associação com síndrome demencial. Para idade, a associação foi mais forte entre aqueles com 90 anos ou mais (RP=8,85; IC95%=2,11-37,11) e 85-89 anos (RP=6,77; IC 95% =1,63-28,12). Em relação à escolaridade, a razão de prevalência foi de 2,77 (IC95%=1,07-7,19) para analfabetos e 2,63 (IC95%=1,31-5,27) para aqueles com 5 a 8 anos de estudos, comparado ao grupo com escolaridade superior. No trabalho com os dados, o grupo de alta complexidade obteve escore de desempenho cognitivo 1,08 pontos mais alto (p=0,019) que o grupo de baixa complexidade. No trabalho com coisas (objetos, equipamentos/máquinas), o escore para complexidade intermediária foi 0,53 pontos mais alto (p=0,044) que o da baixa complexidade. Não houve diferença estatisticamente significativa no desempenho cognitivo entre os níveis de complexidade do trabalho com pessoas.. Conclui-se que a prevalência de síndrome demencial na população estudada foi superior à obtida em estudos de bases populacionais e que a maior prevalência de demência estava associada ao aumento da idade e à baixa escolaridade. Além disto, mostrou-se que a maior complexidade do trabalho com dados e com coisas estava associada com melhor desempenho cognitivo na velhice, independentemente da idade, da escolaridadade, da renda e do tempo de ocupação.

Sobrevida e fatores prognósticos para o câncer de mama em Juiz de Fora, Minas Gerais, na coorte diagnosticada entre 1998 e 2000

Este estudo teve como objetivo analisar a sobrevida e fatores prognósticos para o câncer de mama feminino, com ênfase no papel de variáveis relacionadas aos serviços de saúde. Foram analisadas 782 mulheres com câncer invasivo da mama e submetidas à cirurgia curativa, que realizaram tratamento cirúrgico e/ou terapia complementar no município de Juiz de Fora, Minas Gerais, com diagnóstico da doença entre 1998 e 2000. O recrutamento dos casos foi efetuado a partir de busca ativa nos registros médicos de todos os serviços de saúde que prestam atendimento em oncologia na cidade. O seguimento foi realizado mediante retorno aos prontuários e complementado por busca no banco do Sistema de Informação sobre Mortalidade (SIM), contato telefônico e consulta de situação cadastral no Cadastro de Pessoas Físicas (CPF). As principais variáveis analisadas foram: cor da pele, idade ao diagnóstico, tamanho do tumor, comprometimento de linfonodos, estadiamento, cidade de residência e variáveis relativas aos serviços de saúde, entre outras. As funções de sobrevida foram calculadas por meio do método de Kaplan-Meier. Foi utilizado o modelo de riscos proporcionais de Cox para avaliação dos fatores prognósticos. No primeiro artigo, foi observada taxa de sobrevida específica em cinco anos de 80,9%, sendo identificados tamanho tumoral e comprometimento de linfonodos axilares como importantes fatores prognósticos associados de forma independente à sobrevida pela doença na população de estudo (HR=1,99, IC95%: 1,27-3,10 e HR=3,92, IC95%: 2,49-6,16, respectivamente). No segundo artigo, quando consideradas as variáveis relativas aos serviços de saúde, foi verificada pior sobrevida para as mulheres assistidas no serviço público, embora com significância limítrofe (p=0,05), e para aquelas que não tinham plano privado de saúde, apesar de não significativa (p=0,1). As funções de sobrevida não ajustadas e estratificadas por natureza do serviço de saúde exibiram sobrevida mais desfavorável para as mulheres não brancas e para os casos com nenhum ou menos de 10 linfonodos isolados somente no serviço público, embora com significâncias estatísticas apenas marginais (p=0,09 e p=0,07, respectivamente). Na análise multivariada, foi observado maior risco de óbito nas mulheres que não fizeram uso de hormonioterapia apenas para os casos assistidos no serviço público (HR=1,56; IC95%: 1,01-2,41), independentemente do tamanho tumoral e do status ganglionar axilar. Tais achados sugerem desigualdades sociais e disparidades na prevenção primária e secundária da doença na região estudada, com desvantagem para o serviço público de saúde, enfatizando a maior necessidade de esclarecimento sobre a doença, assim como de diagnóstico e tratamento dos casos em estádios mais precoces. Destacou-se, ainda, o valor de se trabalhar com informações produzidas pelos serviços de saúde responsáveis pela assistência oncológica no país, possibilitando a caracterização do perfil e da sobrevida das pacientes assistidas e fornecendo subsídios aos órgãos competentes do setor saúde local para nortear a adoção de estratégias de prevenção direcionadas ao controle da doença na população avaliada.