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Measurement of local creep properties in stainless steel welds
A high temperature measurement system for creep deformation based on the digital image correlation (DIC) technique is described. The new system is applied to study the behaviour of a multi-pass welded joint in a high temperature tensile test and a load controlled creep test at 545°C. Spatially resolved tensile properties and time dependent creep deformation properties across a thick section type 316 stainless steel multi-pass welded joint are presented and discussed. Significantly lower creep strain rates are observed in the HAZ than in the parent material which is attributed to the introduction of substantial plastic strain in the parent material on initial loading. The weld metal shows the fastest creep rates and a variation that appear to correlate with individual weld passes. The visual information provides not only the local creep strain distribution but also the reduction of area and true stress distribution based on strains measured in the transverse direction. The results demonstrate the capability of the DIC technique for full field measurement of displacement and strain at high temperature long term creep tests
No-arbitrage in discrete-time markets with proportional transaction costs and general information structure
We discuss the no-arbitrage conditions in a general framework for
discrete-time models of financial markets with proportional transaction costs
and general information structure. We extend the results of Kabanov and al.
(2002), Kabanov and al. (2003) and Schachermayer (2004) to the case where
bid-ask spreads are not known with certainty. In the "no-friction" case, we
retrieve the result of Kabanov and Stricker (2003)
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In-situ Neutron Diffraction Studies of Various Metals on Engin-X at ISIS
The Omega deformed B-model for rigid N=2 theories
We give an interpretation of the Omega deformed B-model that leads naturally
to the generalized holomorphic anomaly equations. Direct integration of the
latter calculates topological amplitudes of four dimensional rigid N=2 theories
explicitly in general Omega-backgrounds in terms of modular forms. These
amplitudes encode the refined BPS spectrum as well as new gravitational
couplings in the effective action of N=2 supersymmetric theories. The rigid N=2
field theories we focus on are the conformal rank one N=2 Seiberg-Witten
theories. The failure of holomorphicity is milder in the conformal cases, but
fixing the holomorphic ambiguity is only possible upon mass deformation. Our
formalism applies irrespectively of whether a Lagrangian formulation exists. In
the class of rigid N=2 theories arising from compactifications on local
Calabi-Yau manifolds, we consider the theory of local P2. We calculate motivic
Donaldson-Thomas invariants for this geometry and make predictions for
generalized Gromov-Witten invariants at the orbifold point.Comment: 73 pages, no figures, references added and typos correcte
Local Volatility Calibration by Optimal Transport
The calibration of volatility models from observable option prices is a
fundamental problem in quantitative finance. The most common approach among
industry practitioners is based on the celebrated Dupire's formula [6], which
requires the knowledge of vanilla option prices for a continuum of strikes and
maturities that can only be obtained via some form of price interpolation. In
this paper, we propose a new local volatility calibration technique using the
theory of optimal transport. We formulate a time continuous martingale optimal
transport problem, which seeks a martingale diffusion process that matches the
known densities of an asset price at two different dates, while minimizing a
chosen cost function. Inspired by the seminal work of Benamou and Brenier [1],
we formulate the problem as a convex optimization problem, derive its dual
formulation, and solve it numerically via an augmented Lagrangian method and
the alternative direction method of multipliers (ADMM) algorithm. The solution
effectively reconstructs the dynamic of the asset price between the two dates
by recovering the optimal local volatility function, without requiring any time
interpolation of the option prices
Link Mining for Kernel-based Compound-Protein Interaction Predictions Using a Chemogenomics Approach
Virtual screening (VS) is widely used during computational drug discovery to
reduce costs. Chemogenomics-based virtual screening (CGBVS) can be used to
predict new compound-protein interactions (CPIs) from known CPI network data
using several methods, including machine learning and data mining. Although
CGBVS facilitates highly efficient and accurate CPI prediction, it has poor
performance for prediction of new compounds for which CPIs are unknown. The
pairwise kernel method (PKM) is a state-of-the-art CGBVS method and shows high
accuracy for prediction of new compounds. In this study, on the basis of link
mining, we improved the PKM by combining link indicator kernel (LIK) and
chemical similarity and evaluated the accuracy of these methods. The proposed
method obtained an average area under the precision-recall curve (AUPR) value
of 0.562, which was higher than that achieved by the conventional Gaussian
interaction profile (GIP) method (0.425), and the calculation time was only
increased by a few percent
One-Loop Self Energy and Renormalization of the Speed of Light for some Anisotropic Improved Quark Actions
One-loop corrections to the fermion rest mass M_1, wave function
renormalization Z_2 and speed of light renormalization C_0 are presented for
lattice actions that combine improved glue with clover or D234 quark actions
and keep the temporal and spatial lattice spacings, a_t and a_s, distinct. We
explore a range of values for the anisotropy parameter \chi = a_s/a_t and treat
both massive and massless fermions.Comment: 45 LaTeX pages with 4 postscript figure
Numerical Schemes for Multivalued Backward Stochastic Differential Systems
We define some approximation schemes for different kinds of generalized
backward stochastic differential systems, considered in the Markovian
framework. We propose a mixed approximation scheme for a decoupled system of
forward reflected SDE and backward stochastic variational inequality. We use an
Euler scheme type, combined with Yosida approximation techniques.Comment: 13 page
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