1,424 research outputs found

    Aeroelastic loads prediction for an arrow wing. Task 1: Evaluation of R. P. White's method

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    The separated flow method is evaluated. This method was developed for moderately swept wings with multiple, constant strength vortex systems. The flow on the highly swept wing used in this evaluation is characterized by a single vortex system of continuously varying strength

    3D performance capture for facial animation

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    This work describes how a photogrammetry based 3D capture system can be used as an input device for animation. The 3D Dynamic Capture System is used to capture the motion of a human face, which is extracted from a sequence of 3D models captured at TV frame rate. Initially the positions of a set of landmarks on the face are extracted. These landmarks are then used to provide motion data in two different ways. First, a high level description of the movements is extracted, and these can be used as input to a procedural animation package (i.e. CreaToon). Second the landmarks can be used as registration points for a conformation process where the model to be animated is modified to match the captured model. This approach gives a new sequence of models, which have the structure of the drawn model but the movement of the captured sequence

    Markov Processes, Hurst Exponents, and Nonlinear Diffusion Equations with application to finance

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    We show by explicit closed form calculations that a Hurst exponent H that is not 1/2 does not necessarily imply long time correlations like those found in fractional Brownian motion. We construct a large set of scaling solutions of Fokker-Planck partial differential equations where H is not 1/2. Thus Markov processes, which by construction have no long time correlations, can have H not equal to 1/2. If a Markov process scales with Hurst exponent H then it simply means that the process has nonstationary increments. For the scaling solutions, we show how to reduce the calculation of the probability density to a single integration once the diffusion coefficient D(x,t) is specified. As an example, we generate a class of student-t-like densities from the class of quadratic diffusion coefficients. Notably, the Tsallis density is one member of that large class. The Tsallis density is usually thought to result from a nonlinear diffusion equation, but instead we explicitly show that it follows from a Markov process generated by a linear Fokker-Planck equation, and therefore from a corresponding Langevin equation. Having a Tsallis density with H not equal to 1/2 therefore does not imply dynamics with correlated signals, e.g., like those of fractional Brownian motion. A short review of the requirements for fractional Brownian motion is given for clarity, and we explain why the usual simple argument that H unequal to 1/2 implies correlations fails for Markov processes with scaling solutions. Finally, we discuss the question of scaling of the full Green function g(x,t;x',t') of the Fokker-Planck pde.Comment: to appear in Physica

    Information Theory based on Non-additive Information Content

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    We generalize the Shannon's information theory in a nonadditive way by focusing on the source coding theorem. The nonadditive information content we adopted is consistent with the concept of the form invariance structure of the nonextensive entropy. Some general properties of the nonadditive information entropy are studied, in addition, the relation between the nonadditivity qq and the codeword length is pointed out.Comment: 9 pages, no figures, RevTex, accepted for publication in Phys. Rev. E(an error in proof of theorem 1 was corrected, typos corrected

    Connecting N-representability to Weyl's problem: The one particle density matrix for N = 3 and R = 6

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    An analytic proof is given of the necessity of the Borland-Dennis conditions for 3-representability of a one particle density matrix with rank 6. This may shed some light on Klyachko's recent use of Schubert calculus to find general conditions for N-representability

    Statistical properties of a localization-delocalization transition induced by correlated disorder

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    The exact probability distributions of the resistance, the conductance and the transmission are calculated for the one-dimensional Anderson model with long-range correlated off-diagonal disorder at E=0. It is proved that despite of the Anderson transition in 3D, the functional form of the resistance (and its related variables) distribution function does not change when there exists a Metal-Insulator transition induced by correlation between disorders. Furthermore, we derive analytically all statistical moments of the resistance, the transmission and the Lyapunov Exponent. The growth rate of the average and typical resistance decreases when the Hurst exponent HH tends to its critical value (Hcr=1/2H_{cr}=1/2) from the insulating regime. In the metallic regime H≥1/2H\geq1/2, the distributions become independent of size. Therefore, the resistance and the transmission fluctuations do not diverge with system size in the thermodynamic limit

    Secondary Students' Involvement in Their IEP Meetings: Administrators' Perceptions

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    Secondary administrators in one southwestern state answered a 10-question web-based survey about student preparation for and involvement in their IEP meetings. Almost half of the 456 building-level special education administrative contacts who received our e-mail request completed the survey. Administrators reported that their schools teach students about their disability, invite them to their IEP meetings, encourage their participation at IEP meetings, and solicit student opinions during the meetings. Few administrators expected students to lead their own IEP meeting. Responses differed by administrative role. Principals answered questions differently than special education directors and special education teachers working part-time as administrators. The administrators' perceptions of student involvement differed from the results of direct observations of secondary IEP meetings.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Liver transplantation for arteriohepatic dysplasia (Alagille's syndrome)

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    Thirteen out of 268 children (<18 years old) underwent hepatic transplantation (OLT) for end-stage liver disease (ESLD) associated with arteriohepatic dysplasia (AHD). Seven children are alive and well with normal liver function. Six children died, four within 11 days of the operation and the other two at 4 and 10 months after the OLT. Vascular complications with associated septicemia were responsible for the deaths of three children. Two died of heart failure and circulatory collapse, secondary to pulmonary hypertension and congenital heart disease. The remaining patient died of overwhelming sepsis not associated with technical complications. Seven patients had a portoenterostomy or portocholecystostomy early in life; five of these died after the OLT. Severe cardiovascular abnormalities in some of our patients suggest that complete hemodynamic monitoring with invasive studies should be performed in all patients with AHD, especially in cases of documented hypertrophy of the right ventricle. The improved quality of life in our surviving patients confirms the validity of OLT as a treatment of choice in cases of ESLD due to AHD. Š 1992 Springer-Verlag

    Nonlinear equation for anomalous diffusion: unified power-law and stretched exponential exact solution

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    The nonlinear diffusion equation ∂ρ∂t=DΔ~ρν\frac{\partial \rho}{\partial t}=D \tilde{\Delta} \rho^\nu is analyzed here, where Δ~≡1rd−1∂∂rrd−1−θ∂∂r\tilde{\Delta}\equiv \frac{1}{r^{d-1}}\frac{\partial}{\partial r} r^{d-1-\theta} \frac{\partial}{\partial r}, and dd, θ\theta and ν\nu are real parameters. This equation unifies the anomalous diffusion equation on fractals (ν=1\nu =1) and the spherical anomalous diffusion for porous media (θ=0\theta=0). Exact point-source solution is obtained, enabling us to describe a large class of subdiffusion (θ>(1−ν)d\theta > (1-\nu)d), normal diffusion (θ=(1−ν)d\theta= (1-\nu)d) and superdiffusion (θ<(1−ν)d\theta < (1-\nu)d). Furthermore, a thermostatistical basis for this solution is given from the maximum entropic principle applied to the Tsallis entropy.Comment: 3 pages, 2 eps figure
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