3,655 research outputs found
Robust Sound Event Classification using Deep Neural Networks
The automatic recognition of sound events by computers is an important aspect of emerging applications such as automated surveillance, machine hearing and auditory scene understanding. Recent advances in machine learning, as well as in computational models of the human auditory system, have contributed to advances in this increasingly popular research field. Robust sound event classification, the ability to recognise sounds under real-world noisy conditions, is an especially challenging task. Classification methods translated from the speech recognition domain, using features such as mel-frequency cepstral coefficients, have been shown to perform reasonably well for the sound event classification task, although spectrogram-based or auditory image analysis techniques reportedly achieve superior performance in noise.
This paper outlines a sound event classification framework that compares auditory image front end features with spectrogram image-based front end features, using support vector machine and deep neural network classifiers. Performance is evaluated on a standard robust classification task in different levels of corrupting noise, and with several system enhancements, and shown to compare very well with current state-of-the-art classification techniques
Evaluation of electrohysterogram measured from different gestational weeks for recognizing preterm delivery:a preliminary study using random Forest
A BMS-invariant free scalar model
The BMS (Bondi-van der Burg-Metzner-Sachs) symmetry arises as the asymptotic
symmetry of flat spacetime at null infinity. In particular, the BMS algebra for
three dimensional flat spacetime (BMS) is generated by the super-rotation
generators which form a Virasoro sub-algebra with central charge ,
together with mutually-commuting super-translation generators. The
super-rotation and super-translation generators have non-trivial commutation
relations with another central charge . In this paper, we study a free
scalar theory in two dimensions exhibiting BMS symmetry, which can also be
understood as the ultra-relativistic limit of a free scalar CFT. Upon
canonical quantization on the highest weight vacuum, the central charges are
found to be and . Because of the vanishing central charge
, the theory features novel properties: there exist primary states which
form a multiplet, and the Hilbert space can be organized by an enlarged version
of BMS modules dubbed the staggered modules. We further calculate correlation
functions and the torus partition function, the later of which is also shown
explicitly to be modular invariant.Comment: 59 pages, 5 figures. v2, minor revision: typos correted and some
statement rephrase
γ-MYN: a new algorithm for estimating Ka and Ks with consideration of variable substitution rates
<p>Abstract</p> <p>Background</p> <p>Over the past two decades, there have been several approximate methods that adopt different mutation models and used for estimating nonsynonymous and synonymous substitution rates (Ka and Ks) based on protein-coding sequences across species or even different evolutionary lineages. Among them, MYN method (a Modified version of Yang-Nielsen method) considers three major dynamic features of evolving DNA sequences–bias in transition/transversion rate, nucleotide frequency, and unequal transitional substitution but leaves out another important feature: unequal substitution rates among different sites or nucleotide positions.</p> <p>Results</p> <p>We incorporated a new feature for analyzing evolving DNA sequences–unequal substitution rates among different sites–into MYN method, and proposed a modified version, namely <it>γ </it>(gamma)-MYN, based on an assumption that the evolutionary rate at each site follows a mode of <it>γ</it>-distribution. We applied <it>γ</it>-MYN to analyze the key estimator of selective pressure ω (Ka/Ks) and other relevant parameters in comparison to two other related methods, YN and MYN, and found that neglecting the variation of substitution rates among different sites may lead to biased estimations of ω. Our new method appears to have minimal deviations when relevant parameters vary within normal ranges defined by empirical data.</p> <p>Conclusion</p> <p>Our results indicate that unequal substitution rates among different sites have variable influences on ω under different evolutionary rates while both transition/transversion rate ratio and unequal nucleotide frequencies affect Ka and Ks thus selective pressure ω.</p> <p>Reviewers</p> <p>This paper was reviewed by Kateryna Makova, David A. Liberles (nominated by David H Ardell), Zhaolei Zhang (nominated by Mark Gerstein), and Shamil Sunyaev.</p
Glue-on AdS holography for -deformed CFTs
The deformation is a solvable irrelevant deformation whose
properties depend on the sign of the deformation parameter . In
particular, -deformed CFTs with have been proposed to be
holographically dual to Einstein gravity where the metric satisfies Dirichlet
boundary conditions at a finite cutoff surface. In this paper, we put forward a
holographic proposal for -deformed CFTs with , in which case
the bulk geometry is constructed by gluing a patch of AdS to the original
spacetime. As evidence, we show that the trace flow equation, the
spectrum on the cylinder, and the partition function on the torus and the
sphere, among other results, can all be reproduced from bulk calculations in
glue-on AdS.Comment: 33 pages, 1 figure; v2: clarifications and references added, matches
published versio
Improving Compositional Text-to-image Generation with Large Vision-Language Models
Recent advancements in text-to-image models, particularly diffusion models,
have shown significant promise. However, compositional text-to-image models
frequently encounter difficulties in generating high-quality images that
accurately align with input texts describing multiple objects, variable
attributes, and intricate spatial relationships. To address this limitation, we
employ large vision-language models (LVLMs) for multi-dimensional assessment of
the alignment between generated images and their corresponding input texts.
Utilizing this assessment, we fine-tune the diffusion model to enhance its
alignment capabilities. During the inference phase, an initial image is
produced using the fine-tuned diffusion model. The LVLM is then employed to
pinpoint areas of misalignment in the initial image, which are subsequently
corrected using the image editing algorithm until no further misalignments are
detected by the LVLM. The resultant image is consequently more closely aligned
with the input text. Our experimental results validate that the proposed
methodology significantly improves text-image alignment in compositional image
generation, particularly with respect to object number, attribute binding,
spatial relationships, and aesthetic quality
Generalized bias-variance evaluation of TREC participated systems
Recent research has shown that the improvement of mean retrieval effectiveness (e.g., MAP) may sacrifice the retrieval stability across queries, implying a tradeoff between effectiveness and stability. The evaluation of both effectiveness and stability are often based on a baseline model, which could be weak or biased. In addition, the effectiveness-stability tradeoff has not been systematically or quantitatively evaluated over TREC participated systems. The above two problems, to some extent, limit our awareness of such tradeoff and its impact on developing future IR models. In this paper, motivated by a recently proposed bias-variance based evaluation, we adopt a strong and unbiased “baseline”, which is a virtual target model constructed by the best performance (for each query) among all the participated systems in a retrieval task. We also propose generalized bias variance metrics, based on which a systematic and quantitative evaluation of the effectiveness-stability tradeoff is carried out over the participated systems in the TREC Ad-hoc Track (1993-1999) and Web Track (2010-2012). We observe a clear effectiveness-stability tradeoff, with a trend of becoming more obvious in more recent years. This implies that when we pursue more effective IR systems over years, the stability has become problematic and could have been largely overlooked
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