6,313 research outputs found
Early stopping for statistical inverse problems via truncated SVD estimation
We consider truncated SVD (or spectral cut-off, projection) estimators for a
prototypical statistical inverse problem in dimension . Since calculating
the singular value decomposition (SVD) only for the largest singular values is
much less costly than the full SVD, our aim is to select a data-driven
truncation level only based on the knowledge of
the first singular values and vectors. We analyse in detail
whether sequential {\it early stopping} rules of this type can preserve
statistical optimality. Information-constrained lower bounds and matching upper
bounds for a residual based stopping rule are provided, which give a clear
picture in which situation optimal sequential adaptation is feasible. Finally,
a hybrid two-step approach is proposed which allows for classical oracle
inequalities while considerably reducing numerical complexity.Comment: slightly modified version. arXiv admin note: text overlap with
arXiv:1606.0770
Unusual presentation of acute annular urticaria: A case report
Acute urticarial lesions may display central clearing with ecchymotic or haemorrhagic hue, often misdiagnosed as erythema
multiforme, serum-sickness-like reactions, or urticarial vasculitis. We report a case of acute annular urticaria with unusual
presentation occurring in a 20-month-old child to emphasize the distinctive morphologic manifestations in a single disease.
Clinicians who care for children should be able to differentiate acute urticaria from its clinical mimics. A directed history and
physical examination can reliably orientate necessary diagnostic testing and allow for appropriate treatment
Consumers' immediate memory for prices
In this article, the authors examine the cognitive mechanics involved in keeping prices in short-terme memory for subsequent recall. Consumers code and store prices verbally, visually, and in terms of their magnitude. The encoding used influences immediate recall performance. The memorability of prices depends on their verbal length, usualness and overall magnitude. They find that the performance of consumers recall prices better than what previous digit span studies with simple numbers have suggested.consumer behavior; numerical cognition; price memory
Integration of an object formalism within a hybrid dynamic simulation environment
PrODHyS is a general object-oriented environment which provides common and reusable components designed for the development and the management of dynamic simulation of systems engineering. Its major characteristic is its ability to simulate processes described by a hybrid model. In this framework, this paper focuses on the "Object Differential Petri Net" (ODPN) formalism integrated within PrODHyS. The use of this formalism is illustrated through a didactic example relating to the field of Chemical Process System Engineering (PSE)
Topological transformations of speckles
Deterministic control of coherent random light is highly important for
information transmission through complex media. However, only a few simple
speckle transformations can be achieved through diffusers without prior
characterization. As recently shown, spiral wavefront modulation of the
impinging beam allows permuting intensity maxima and intrinsic -charged
optical vortices. Here, we study this cyclic-group algebra when combining
spiral phase transforms of charge , with - and -point-group
symmetry star-like amplitude modulations. This combination allows statistical
strengthening of permutations and controlling the period to be 3 and 4,
respectively. Phase saddle-points are shown to complete the cycle. These
results offer new tools to manipulate critical points in speckles.Comment: 14 pages, 10 figures, 4 table
Generating Homology Relationships by Alignment of Anatomical Ontologies
The anatomy of model species is described in ontologies, which are used to standardize the annotations of experimental data, such as gene expression patterns. To compare such data between species, we aim to establish homology relations between ontologies describing different species. We present a new algorithm, and its implementation in the software Homolonto, to create new relationships between anatomical ontologies, based on the homology concept. These relationships and the Homolonto software are available at "http://bgee.unil.ch/.":http://bgee.unil.ch
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