294 research outputs found
Optimal investment with intermediate consumption under no unbounded profit with bounded risk
We consider the problem of optimal investment with intermediate consumption
in a general semimartingale model of an incomplete market, with preferences
being represented by a utility stochastic field. We show that the key
conclusions of the utility maximization theory hold under the assumptions of no
unbounded profit with bounded risk (NUPBR) and of the finiteness of both primal
and dual value functions.Comment: 10 pages, revised version, to appear in the Applied Probability
Journal
The profinite completion of -manifold groups, fiberedness and the Thurston norm
We show that a regular isomorphism of profinite completion of the fundamental
groups of two 3-manifolds and induces an isometry of the Thurston
norms and a bijection between the fibered classes. We study to what extent does
the profinite completion of knot groups distinguish knots and show that it
distinguishes each torus knot and the figure eight knot among all knots. We
show also that it distinguishes between hyperbolic knots with cyclically
commensurable complements under the assumption that their Alexander polynomials
have at least one zero which is not a root of unity.Comment: 22 page
Implementation and testing of a simple data assimilation algorithm in the regional air pollution forecast model, DEOM
The Evolution of Optical Fiber Sensors Technologies During the 35 Last Years and Their Applications in Structure Health Monitoring
Conference of 7th European Workshop on Structural Health Monitoring, EWSHM 2014 ; Conference Date: 8 July 2014 Through 11 July 2014; Conference Code:113023International audienceSince late 70s, (quasi-)distributed OFS have been developed, 12 countries producing 85% of the global effort. Since mid-80s, OFS has caught attention in many sectors where SHM is a matter of concern (civil engineering, composites, oil & gas, renewable energies, safety...). Today, OFS is became a strategic domain, especially in Asia, and China invests a lot since 7-8 years. Top 12 countries involved in SHM are, almost the same than in OFS, having published 80% of the total. Statistics proves that OFS is now the second sensing technology for SHM, and 2/3 concern the FBG sensing
Recension de William Andy Corsaro, The Sociology of Childhood, SAGE, 2015
Recension d'un ouvrageCette quatrième édition d'un des premiers manuels consacré à la sociologie de l'enfance, initialement publié en 1997, ne saurait être une surprise, même si l'auteur semble peu connu en langue française. À notre connaissance, la seule traduction disponible en français a été publiée en 2011
Turbulence Model Comparison for Compact Plate Heat Exchanger Design Application.
In the framework of the Gas-Power Conversion System for the Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID) project design, works done at CEA are focused on the design of the sodium-gas heat exchanger. Compact plate heat exchangers are indicated as the most suitable technology for such applications. An innovative compact heat exchanger geometry is proposed in this paper: its innovationconsists increatinga 3D mixing flow. The proposed geometry has also very good mechanical resistance to high pressure gradients, being suitable for a large variety of flow applications. The flowfield inside such a channel is experimentally studied using the Laser Doppler Velocimetry (LDV) technique. The main velocity, the radial velocity as well as the Reynolds stressesare measured: data show the high level of flow mixing and the 3D flow pattern inside the channel. The experimental measurements are then used to validate turbulence models: in particular Reynolds-Averaged Navier-Stokes (RANS) equations are closed using both isotropic 2-equation isotropic eddy viscosity models and a Non-Linear Eddy Viscosity Model (NLEVM). Presented results represent the first step in the assessment of innovative high-performance compact plate heat exchangers that can be used to increase the plant efficiency as well as decrease the capital cost of the single component
Optimal approximate matrix product in terms of stable rank
We prove, using the subspace embedding guarantee in a black box way, that one
can achieve the spectral norm guarantee for approximate matrix multiplication
with a dimensionality-reducing map having
rows. Here is the maximum stable rank, i.e. squared ratio of
Frobenius and operator norms, of the two matrices being multiplied. This is a
quantitative improvement over previous work of [MZ11, KVZ14], and is also
optimal for any oblivious dimensionality-reducing map. Furthermore, due to the
black box reliance on the subspace embedding property in our proofs, our
theorem can be applied to a much more general class of sketching matrices than
what was known before, in addition to achieving better bounds. For example, one
can apply our theorem to efficient subspace embeddings such as the Subsampled
Randomized Hadamard Transform or sparse subspace embeddings, or even with
subspace embedding constructions that may be developed in the future.
Our main theorem, via connections with spectral error matrix multiplication
shown in prior work, implies quantitative improvements for approximate least
squares regression and low rank approximation. Our main result has also already
been applied to improve dimensionality reduction guarantees for -means
clustering [CEMMP14], and implies new results for nonparametric regression
[YPW15].
We also separately point out that the proof of the "BSS" deterministic
row-sampling result of [BSS12] can be modified to show that for any matrices
of stable rank at most , one can achieve the spectral norm
guarantee for approximate matrix multiplication of by deterministically
sampling rows that can be found in polynomial
time. The original result of [BSS12] was for rank instead of stable rank. Our
observation leads to a stronger version of a main theorem of [KMST10].Comment: v3: minor edits; v2: fixed one step in proof of Theorem 9 which was
wrong by a constant factor (see the new Lemma 5 and its use; final theorem
unaffected
- …
