12,840 research outputs found
Algorithmic Programming Language Identification
Motivated by the amount of code that goes unidentified on the web, we
introduce a practical method for algorithmically identifying the programming
language of source code. Our work is based on supervised learning and
intelligent statistical features. We also explored, but abandoned, a
grammatical approach. In testing, our implementation greatly outperforms that
of an existing tool that relies on a Bayesian classifier. Code is written in
Python and available under an MIT license.Comment: 11 pages. Code:
https://github.com/simon-weber/Programming-Language-Identificatio
Absolutely Continuous Spectrum for Random Schroedinger Operators on the Bethe Strip
The Bethe Strip of width is the cartesian product \B\times\{1,...,m\},
where \B is the Bethe lattice (Cayley tree). We prove that Anderson models on
the Bethe strip have "extended states" for small disorder. More precisely, we
consider Anderson-like Hamiltonians \;H_\lambda=\frac12 \Delta \otimes 1 + 1
\otimes A + \lambda \Vv on a Bethe strip with connectivity , where
is an symmetric matrix, \Vv is a random matrix potential, and
is the disorder parameter. Given any closed interval , where
and are the smallest and largest
eigenvalues of the matrix , we prove that for small the random
Schr\"odinger operator has purely absolutely continuous spectrum
in with probability one and its integrated density of states is
continuously differentiable on the interval
Fast Bayesian Optimization of Machine Learning Hyperparameters on Large Datasets
Bayesian optimization has become a successful tool for hyperparameter
optimization of machine learning algorithms, such as support vector machines or
deep neural networks. Despite its success, for large datasets, training and
validating a single configuration often takes hours, days, or even weeks, which
limits the achievable performance. To accelerate hyperparameter optimization,
we propose a generative model for the validation error as a function of
training set size, which is learned during the optimization process and allows
exploration of preliminary configurations on small subsets, by extrapolating to
the full dataset. We construct a Bayesian optimization procedure, dubbed
Fabolas, which models loss and training time as a function of dataset size and
automatically trades off high information gain about the global optimum against
computational cost. Experiments optimizing support vector machines and deep
neural networks show that Fabolas often finds high-quality solutions 10 to 100
times faster than other state-of-the-art Bayesian optimization methods or the
recently proposed bandit strategy Hyperband
Stabilizing discontinuous Galerkin methods using Dafermos' entropy rate criterion
A novel approach for the stabilization of the discontinuous Galerkin method
based on the Dafermos entropy rate crition is presented. The approach is
centered around the efficient solution of linear or nonlinear optimization
problems in every timestep as a correction to the basic discontinuous Galerkin
scheme. The thereby enforced Dafermos criterion results in improved stability
compared to the basic method while retaining the order of the method in
numerical experiments. Further modification of the optimization problem allows
also to enforce classical entropy inequalities for the scheme. The proposed
stabilization is therefore an alternative to flux-differencing, finite-volume
subcells, artificial viscosity, modal filtering, and other shock capturing
procedures
Stabilizing Discontinuous Galerkin Methods Using Dafermos' Entropy Rate Criterion: II -- Systems of Conservation Laws and Entropy Inequality Predictors
A novel approach for the stabilization of the Discontinuous Galerkin method
based on the Dafermos entropy rate crition is presented. First, estimates for
the maximal possible entropy dissipation rate of a weak solution are derived.
Second, families of conservative Hilbert-Schmidt operators are identified to
dissipate entropy. Steering these operators using the bounds on the entropy
dissipation results in high-order accurate shock-capturing DG schemes for the
Euler equations, satisfying the entropy rate criterion and an entropy
inequality
Discovery-led refinement in e-discovery investigations: sensemaking, cognitive ergonomics and system design.
Given the very large numbers of documents involved in e-discovery investigations, lawyers face a considerable challenge of collaborative sensemaking. We report findings from three workplace studies which looked at different aspects of how this challenge was met. From a sociotechnical perspective, the studies aimed to understand how investigators collectively and individually worked with information to support sensemaking and decision making. Here, we focus on discovery-led refinement; specifically, how engaging with the materials of the investigations led to discoveries that supported refinement of the problems and new strategies for addressing them. These refinements were essential for tractability. We begin with observations which show how new lines of enquiry were recursively embedded. We then analyse the conceptual structure of a line of enquiry and consider how reflecting this in e-discovery support systems might support scalability and group collaboration. We then focus on the individual activity of manual document review where refinement corresponded with the inductive identification of classes of irrelevant and relevant documents within a collection. Our observations point to the effects of priming on dealing with these efficiently and to issues of cognitive ergonomics at the human–computer interface. We use these observations to introduce visualisations that might enable reviewers to deal with such refinements more efficiently
Comments: A Right to Testimony of Immunized Defense Witnesses
In 1980, the court of appeals for the Third Circuit, in Government of Virgin Islands v. Smith, held that a defendant\u27s right to evidence in a criminal trial included a right to immunity /or his witnesses. Since that time, the district court of Maryland has similarly upheld, in United States v. Lyon, a defendant\u27s right to testimony even though the witness may require immunity. This article discusses the competing interests weighing for and against defense witness immunity and suggests that once it is determined that a defendant has a right to certain testimony, it is proper to burden the government with a choice of alternatives to ensure the defendant that right
Comments: A Right to Testimony of Immunized Defense Witnesses
In 1980, the court of appeals for the Third Circuit, in Government of Virgin Islands v. Smith, held that a defendant\u27s right to evidence in a criminal trial included a right to immunity /or his witnesses. Since that time, the district court of Maryland has similarly upheld, in United States v. Lyon, a defendant\u27s right to testimony even though the witness may require immunity. This article discusses the competing interests weighing for and against defense witness immunity and suggests that once it is determined that a defendant has a right to certain testimony, it is proper to burden the government with a choice of alternatives to ensure the defendant that right
Stimulus-invariant processing and spectrotemporal reverse correlation in primary auditory cortex
The spectrotemporal receptive field (STRF) provides a versatile and
integrated, spectral and temporal, functional characterization of single cells
in primary auditory cortex (AI). In this paper, we explore the origin of, and
relationship between, different ways of measuring and analyzing an STRF. We
demonstrate that STRFs measured using a spectrotemporally diverse array of
broadband stimuli -- such as dynamic ripples, spectrotemporally white noise,
and temporally orthogonal ripple combinations (TORCs) -- are very similar,
confirming earlier findings that the STRF is a robust linear descriptor of the
cell. We also present a new deterministic analysis framework that employs the
Fourier series to describe the spectrotemporal modulations contained in the
stimuli and responses. Additional insights into the STRF measurements,
including the nature and interpretation of measurement errors, is presented
using the Fourier transform, coupled to singular-value decomposition (SVD), and
variability analyses including bootstrap. The results promote the utility of
the STRF as a core functional descriptor of neurons in AI.Comment: 42 pages, 8 Figures; to appear in Journal of Computational
Neuroscienc
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