115 research outputs found
Is Bilingualism a boon or bane for children with Communication Disorders?
Journal of Child Language Acquisition and Development - JCLA
Optimal PAC Bounds Without Uniform Convergence
In statistical learning theory, determining the sample complexity of
realizable binary classification for VC classes was a long-standing open
problem. The results of Simon and Hanneke established sharp upper bounds in
this setting. However, the reliance of their argument on the uniform
convergence principle limits its applicability to more general learning
settings such as multiclass classification. In this paper, we address this
issue by providing optimal high probability risk bounds through a framework
that surpasses the limitations of uniform convergence arguments.
Our framework converts the leave-one-out error of permutation invariant
predictors into high probability risk bounds. As an application, by adapting
the one-inclusion graph algorithm of Haussler, Littlestone, and Warmuth, we
propose an algorithm that achieves an optimal PAC bound for binary
classification. Specifically, our result shows that certain aggregations of
one-inclusion graph algorithms are optimal, addressing a variant of a classic
question posed by Warmuth.
We further instantiate our framework in three settings where uniform
convergence is provably suboptimal. For multiclass classification, we prove an
optimal risk bound that scales with the one-inclusion hypergraph density of the
class, addressing the suboptimality of the analysis of Daniely and
Shalev-Shwartz. For partial hypothesis classification, we determine the optimal
sample complexity bound, resolving a question posed by Alon, Hanneke, Holzman,
and Moran. For realizable bounded regression with absolute loss, we derive an
optimal risk bound that relies on a modified version of the scale-sensitive
dimension, refining the results of Bartlett and Long. Our rates surpass
standard uniform convergence-based results due to the smaller complexity
measure in our risk bound.Comment: 27 page
The manifold rheology of fluidized granular media
Fluidized granular media have a rich rheology: measuring shear stress
as a function of shear rate , they exhibit Newtonian
behavior for low densities and shear rates, develop a
yield stress for intermediate shear rates and densities approaching the
granular glass transition, and finally, cross over to shear-thickening Bagnold
scaling, . This wealth of flow-behaviors makes
fluidized beds a fascinating material, but also one that is challenging to
encompass into a global theory, despite its relevance for optimizing industrial
processes and predicting natural hazards. We provide careful measurements
spanning eight orders of magnitude in shear rate, and show that all these
rheological regimes can be described qualitatively and quantitatively using the
granular integration through transient formalism, a theory for glassy dynamics
under shear adapted to granular fluids
Next-generation sequencing for endocrine cancers : Recent advances and challenges
Contemporary molecular biology research tools have enriched numerous areas of biomedical research that address challenging diseases, including endocrine cancers (pituitary, thyroid, parathyroid, adrenal, testicular, ovarian, and neuroendocrine cancers). These tools have placed several intriguing clues before the scientific community. Endocrine cancers pose a major challenge in health care and research despite considerable attempts by researchers to understand their etiology. Microarray analyses have provided gene signatures from many cells, tissues, and organs that can differentiate healthy states from diseased ones, and even show patterns that correlate with stages of a disease. Microarray data can also elucidate the responses of endocrine tumors to therapeutic treatments. The rapid progress in next-generation sequencing methods has overcome many of the initial challenges of these technologies, and their advantages over microarray techniques have enabled them to emerge as valuable aids for clinical research applications (prognosis, identification of drug targets, etc.). A comprehensive review describing the recent advances in next-generation sequencing methods and their application in the evaluation of endocrine and endocrine-related cancers is lacking. The main purpose of this review is to illustrate the concepts that collectively constitute our current view of the possibilities offered by next-generation sequencing technological platforms, challenges to relevant applications, and perspectives on the future of clinical genetic testing of patients with endocrine tumors. We focus on recent discoveries in the use of next-generation sequencing methods for clinical diagnosis of endocrine tumors in patients and conclude with a discussion on persisting challenges and future objectives
Tunable solidification of cornstarch under impact: how to make someone walking on cornstarch sink
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