275,018 research outputs found
Progressive surface modeling scheme from unorganised curves
This paper presents a novel surface modelling scheme to construct a freeform surface
progressively from unorganised curves representing the boundary and interior characteristic curves.
The approach can construct a base surface model from four ordinary or composite boundary curves
and support incremental surface updating from interior characteristic curves, some of which may not
be on the final surface. The base surface is first constructed as a regular Coons surface and upon receiving an interior curve sketch, it is then updated. With this progressive modelling scheme, a final
surface with multiple sub-surfaces can be obtained from a set of unorganised curves and transferred
to commercial surface modelling software for detailed modification. The approach has been tested
with examples based on 3D motion sketches; it is capable of dealing with unorganised design curves
for surface modelling in conceptual design. Its limitations have been discussed
Risk Minimization, Regret Minimization and Progressive Hedging Algorithms
This paper begins with a study on the dual representations of risk and regret
measures and their impact on modeling multistage decision making under
uncertainty. A relationship between risk envelopes and regret envelopes is
established by using the Lagrangian duality theory. Such a relationship opens a
door to a decomposition scheme, called progressive hedging, for solving
multistage risk minimization and regret minimization problems. In particular,
the classical progressive hedging algorithm is modified in order to handle a
new class of linkage constraints that arises from reformulations and other
applications of risk and regret minimization problems. Numerical results are
provided to show the efficiency of the progressive hedging algorithms.Comment: 21 pages, 2 figure
Ramsey Rule with Progressive Utility in Long Term Yield Curves Modeling
The purpose of this paper relies on the study of long term yield curves
modeling. Inspired by the economic litterature, it provides a financial
interpretation of the Ramsey rule that links discount rate and marginal utility
of aggregate optimal consumption. For such a long maturity modelization, the
possibility of adjusting preferences to new economic information is crucial.
Thus, after recalling some important properties on progressive utility, this
paper first provides an extension of the notion of a consistent progressive
utility to a consistent pair of progressive utilities of investment and
consumption. An optimality condition is that the utility from the wealth
satisfies a second order SPDE of HJB type involving the Fenchel-Legendre
transform of the utility from consumption. This SPDE is solved in order to give
a full characterization of this class of consistent progressive pair of
utilities. An application of this results is to revisit the classical backward
optimization problem in the light of progressive utility theory, emphasizing
intertemporal-consistency issue. Then we study the dynamics of the marginal
utility yield curve, and give example with backward and progressive power
utilities
Spatial distribution of nuclei in progressive nucleation: modeling and application
Phase transformations ruled by non-simultaneous nucleation and growth do not
lead to random distribution of nuclei. Since nucleation is only allowed in the
untransformed portion of space, positions of nuclei are correlated. In this
article an analytical approach is presented for computing pair-correlation
function of nuclei in progressive nucleation. This quantity is further employed
for characterizing the spatial distribution of nuclei through the nearest
neighbor distribution function. The modeling is developed for nucleation in 2D
space with power growth law and it is applied to describe electrochemical
nucleation where correlation effects are significant. Comparison with both
computer simulations and experimental data lends support to the model which
gives insights into the transition from Poissonian to correlated nearest
neighbor probability density.Comment: 30 pages; 9 figure
Ramsey Rule with Progressive utility and Long Term Affine Yields Curves
The purpose of this paper relies on the study of long term affine yield
curves modeling. It is inspired by the Ramsey rule of the economic literature,
that links discount rate and marginal utility of aggregate optimal consumption.
For such a long maturity modelization, the possibility of adjusting preferences
to new economic information is crucial, justifying the use of progressive
utility. This paper studies, in a framework with affine factors, the yield
curve given from the Ramsey rule. It first characterizes consistent progressive
utility of investment and consumption, given the optimal wealth and consumption
processes. A special attention is paid to utilities associated with linear
optimal processes with respect to their initial conditions, which is for
example the case of power progressive utilities. Those utilities are the basis
point to construct other progressive utilities generating non linear optimal
processes but leading yet to still tractable computations. This is of
particular interest to study the impact of initial wealth on yield curves.Comment: arXiv admin note: substantial text overlap with arXiv:1404.189
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