7,783 research outputs found
Near-IR variability properties of a selected sample of AGB stars
We present the results of a near-infrared monitoring programme of a selected
sample of stars, initially suspected to be Mira variables and OH/IR stars,
covering more than a decade of observations. The objects monitored cover the
typical range of IRAS colours shown by O-rich stars on the Asymptotic Giant
Branch and show a surprisingly large diversity of variability properties. 16
objects are confirmed as large-amplitude variables. Periods between 360 and
1800 days and typical amplitudes from 1 to 2 magnitudes could be determined for
nine of them. In three light curves we find a systematic decrease of the mean
brightness, two light curves show pronounced asymmetry. One source, IRAS
07222-2005, shows infrared colours typical of Mira variables but pulsates with
a much longer period (approx. 1200 days) than a normal Mira. Two objects are
ither close to (IRAS 03293+6010) or probably in (IRAS 18299-1705) the post-AGB
phase. In IRAS 16029-3041 we found a systematic increase of the H-K colour of
approximately 1 magnitude, which we interpret as evidence of a recent episode
of enhanced mass loss. IRAS 18576+0341, a heavily obscured Luminous Blue
Variable was also monitored. The star showed a continued decrease of brightness
over a period of 7 years (1995 - 2002).Comment: 9 pages + 3 appendix, 36 figures, photometry table, accepted in
Astronomy & Astrophysic
LCrowdV: Generating Labeled Videos for Simulation-based Crowd Behavior Learning
We present a novel procedural framework to generate an arbitrary number of
labeled crowd videos (LCrowdV). The resulting crowd video datasets are used to
design accurate algorithms or training models for crowded scene understanding.
Our overall approach is composed of two components: a procedural simulation
framework for generating crowd movements and behaviors, and a procedural
rendering framework to generate different videos or images. Each video or image
is automatically labeled based on the environment, number of pedestrians,
density, behavior, flow, lighting conditions, viewpoint, noise, etc.
Furthermore, we can increase the realism by combining synthetically-generated
behaviors with real-world background videos. We demonstrate the benefits of
LCrowdV over prior lableled crowd datasets by improving the accuracy of
pedestrian detection and crowd behavior classification algorithms. LCrowdV
would be released on the WWW
Transplant Acceptance Following Anti-CD4 Versus Anti-CD40L Therapy: Evidence for Differential Maintenance of Graft-Reactive T Cells
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73145/1/j.1600-6143.2008.02372.x.pd
Formal Verification of Synchronous Data-flow Program Transformations Toward Certified Compilers
International audienceTranslation validation was introduced in the 90's by Pnueli et al. as a technique to formally verify the correctness of code generators. Rather than certifying the code generator or exhaustively qualifying it, translation validators attempt to verify that program transformations preserve semantics. In this work, we adopt this approach to formally verify that the clock semantics and data dependence are preserved during the compilation of the Signal compiler. Translation validation is implemented for every compilation phase from the initial phase until the latest phase where the executable code is generated, by proving that the transformation in each phase of the compiler preserves the semantics. We represent the clock semantics, the data dependence of a program and its transformed counterpart as first-order formulas which are called Clock Models and Synchronous Dependence Graphs (SDGs), respectively. Then we introduce clock refinement and dependence refinement relations which express the preservation of clock semantics and dependence, as a relation on clock models and SDGs, respectively. Our validator does not require any instrumentation or modification of the compiler, nor any rewriting of the source program
Mycobacterium tuberculosis Beijing Genotype and Risk for Treatment Failure and Relapse, Vietnam
Among 2,901 new smear-positive tuberculosis cases in Ho Chi Minh City, Vietnam, 40 cases of treatment failure and 39 relapsing cases were diagnosed. All initial and follow-up Mycobacterium tuberculosis isolates of these case-patients had (nearly) identical restriction fragment length polymorphism patterns, and the Beijing genotype was a significant risk factor for treatment failure and relapse (odds ratio 2.8, 95% confidence interval 1.5 to 5.2)
Automated metamorphic testing of variability analysis tools
Variability determines the capability of software applications to be configured and customized. A common
need during the development of variability–intensive systems is the automated analysis of their underlying
variability models, e.g. detecting contradictory configuration options. The analysis operations that are
performed on variability models are often very complex, which hinders the testing of the corresponding
analysis tools and makes difficult, often infeasible, to determine the correctness of their outputs, i.e.
the well–known oracle problem in software testing. In this article, we present a generic approach for
the automated detection of faults in variability analysis tools overcoming the oracle problem. Our work
enables the generation of random variability models together with the exact set of valid configurations
represented by these models. These test data are generated from scratch using step–wise transformations
and assuring that certain constraints (a.k.a. metamorphic relations) hold at each step. To show the feasibility
and generalizability of our approach, it has been used to automatically test several analysis tools in three
variability domains: feature models, CUDF documents and Boolean formulas. Among other results, we
detected 19 real bugs in 7 out of the 15 tools under test.CICYT TIN2012-32273CICYT IPT-2012- 0890-390000Junta de AndalucĂa TIC-5906Junta de AndalucĂa P12-TIC- 186
Detecting the direction of a signal on high-dimensional spheres: Non-null and Le Cam optimality results
We consider one of the most important problems in directional statistics,
namely the problem of testing the null hypothesis that the spike direction
of a Fisher-von Mises-Langevin distribution on the -dimensional
unit hypersphere is equal to a given direction . After a reduction
through invariance arguments, we derive local asymptotic normality (LAN)
results in a general high-dimensional framework where the dimension goes
to infinity at an arbitrary rate with the sample size , and where the
concentration behaves in a completely free way with , which
offers a spectrum of problems ranging from arbitrarily easy to arbitrarily
challenging ones. We identify various asymptotic regimes, depending on the
convergence/divergence properties of , that yield different
contiguity rates and different limiting experiments. In each regime, we derive
Le Cam optimal tests under specified and we compute, from the Le Cam
third lemma, asymptotic powers of the classical Watson test under contiguous
alternatives. We further establish LAN results with respect to both spike
direction and concentration, which allows us to discuss optimality also under
unspecified . To investigate the non-null behavior of the Watson test
outside the parametric framework above, we derive its local asymptotic powers
through martingale CLTs in the broader, semiparametric, model of rotationally
symmetric distributions. A Monte Carlo study shows that the finite-sample
behaviors of the various tests remarkably agree with our asymptotic results.Comment: 47 pages, 4 figure
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