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Yuriy Mishchenko

Publications and source records attributed to Yuriy Mishchenko.

15 recordsLinked to original sources

Latency Control for Keyword Spotting

Conversational agents commonly utilize keyword spotting (KWS) to initiate voice interaction with the user. For user experience and privacy considerations, existing approaches to KWS largely focus on accuracy, which can often come at the expense of introduced latency. To address this tradeoff, we propose a novel approach to control KWS model latency and which generalizes to any loss function without explicit knowledge of the keyword endpoint. Through a single, tunable hyperparameter, our approach enables one to balance detection latency and accuracy for the targeted application. Empirically, we show that our approach gives superior performance under latency constraints when compared to existing methods. Namely, we make a substantial 25\% relative false accepts improvement for a fixed latency target when compared to the baseline state-of-the-art. We also show that when our approach is used in conjunction with a max-pooling loss, we are able to improve relative false accepts by 25 % at a fixed latency when compared to cross entropy loss.

eess.AS

Towards Data-efficient Modeling for Wake Word Spotting

Wake word (WW) spotting is challenging in far-field not only because of the interference in signal transmission but also the complexity in acoustic environments. Traditional WW model training requires large amount of in-domain WW-specific data with substantial human annotations therefore it is hard to build WW models without such data. In this paper we present data-efficient solutions to address the challenges in WW modeling, such as domain-mismatch, noisy conditions, limited annotation, etc. Our proposed system is composed of a multi-condition training pipeline with a stratified data augmentation, which improves the model robustness to a variety of predefined acoustic conditions, together with a semi-supervised learning pipeline to accurately extract the WW and confusable examples from untranscribed speech corpus. Starting from only 10 hours of domain-mismatched WW audio, we are able to enlarge and enrich the training dataset by 20-100 times to capture the acoustic complexity. Our experiments on real user data show that the proposed solutions can achieve comparable performance of a production-grade model by saving 97\% of the amount of WW-specific data collection and 86\% of the bandwidth for annotation.

eess.AS

Accurate Detection of Wake Word Start and End Using a CNN

Small footprint embedded devices require keyword spotters (KWS) with small model size and detection latency for enabling voice assistants. Such a keyword is often referred to as \textit{wake word} as it is used to wake up voice assistant enabled devices. Together with wake word detection, accurate estimation of wake word endpoints (start and end) is an important task of KWS. In this paper, we propose two new methods for detecting the endpoints of wake words in neural KWS that use single-stage word-level neural networks. Our results show that the new techniques give superior accuracy for detecting wake words' endpoints of up to 50 msec standard error versus human annotations, on par with the conventional Acoustic Model plus HMM forced alignment. To our knowledge, this is the first study of wake word endpoints detection methods for single-stage neural KWS.

eess.AS

Dark matter phenomenology of high speed galaxy cluster collisions

We perform a general computational analysis of possible post-collision mass distributions in high-speed galaxy cluster collisions in the presence of weakly self-interacting dark matter. Using this analysis, we show that weakly self-scattering dark matter can impart subtle yet measurable features in the mass distributions of colliding galaxy clusters even without significant disruptions to the dark matter halos of the colliding galaxy clusters themselves. Most profound such evidences are found to reside in the tails of dark matter halos' distributions, in the space between the colliding galaxy clusters. This feature appears in our simulations as shells of scattered dark matter expanding in alignment with the outgoing original galaxy clusters, contributing significant densities to projected mass distributions at large distances from collision centers and large scattering angles up to $90^\circ$. Our simulations indicate that as much as 20% of the total collision's mass may be deposited into such structures without noticeable disruptions to the main galaxy clusters. Such structures at large scattering angles are forbidden however in purely gravitational high-speed galaxy cluster collisions. Convincing identification of such structures in real colliding galaxy clusters would be a clear indication of the self-interacting nature of dark matter. Our findings may explain the dark matter ring feature recently found in the long-range reconstructions of the mass distribution of the colliding galaxy cluster CL0024+017.

astro-ph.CO

Rosetta Brains: A Strategy for Molecularly-Annotated Connectomics

We propose a neural connectomics strategy called Fluorescent In-Situ Sequencing of Barcoded Individual Neuronal Connections (FISSEQ-BOINC), leveraging fluorescent in situ nucleic acid sequencing in fixed tissue (FISSEQ). FISSEQ-BOINC exhibits different properties from BOINC, which relies on bulk nucleic acid sequencing. FISSEQ-BOINC could become a scalable approach for mapping whole-mammalian-brain connectomes with rich molecular annotations.

q-bio.NC

Efficient methods for sampling spike trains in networks of coupled neurons

Monte Carlo approaches have recently been proposed to quantify connectivity in neuronal networks. The key problem is to sample from the conditional distribution of a single neuronal spike train, given the activity of the other neurons in the network. Dependencies between neurons are usually relatively weak; however, temporal dependencies within the spike train of a single neuron are typically strong. In this paper we develop several specialized Metropolis--Hastings samplers which take advantage of this dependency structure. These samplers are based on two ideas: (1) an adaptation of fast forward--backward algorithms from the theory of hidden Markov models to take advantage of the local dependencies inherent in spike trains, and (2) a first-order expansion of the conditional likelihood which allows for efficient exact sampling in the limit of weak coupling between neurons. We also demonstrate that these samplers can effectively incorporate side information, in particular, noisy fluorescence observations in the context of calcium-sensitive imaging experiments. We quantify the efficiency of these samplers in a variety of simulated experiments in which the network parameters are closely matched to data measured in real cortical networks, and also demonstrate the sampler applied to real calcium imaging data.

stat.AP

Higher Fock State Contributions to the Generalized Parton Distribution of Pion

We discuss the higher Fock state (q \bar q g) contributions to the nonzero value of the pion GPD at the crossover point x = zeta between the DGLAP and ERBL regions. Using the phenomenological light-front constituent quark model, we confirm that the higher Fock state contributions indeed give a nonzero value of the GPD at the crossover point. Iterating the light-front quark model wave function of the lowest q \bar q Fock state with the Bethe-Salpeter kernel corresponding to the one-gluon-exchange, we include all possible time-ordered q \bar q g Fock state contributions and obtain the pion GPD satisfying necessary sum rules and continuity conditions.

hep-ph

A novel variational approach for Quantum Field Theory: example of study of the ground state and phase transition in Nonlinear Sigma Model

We discuss a novel form of the variational approach in Quantum Field Theory in which the trial quantum configuration is represented directly in terms of relevant expectation values rather than, e.g., increasingly complicated structure from Fock space. The quantum algebra imposes constraints on such expectation values so that the variational problem is formulated here as an optimization under constraints. As an example of application of such approach we consider the study of ground state and critical properties in a variant of nonlinear sigma model.

quant-ph

Exploring Properties of Dark and Visible Mass Distribution on Different Scales in the Universe

In this short note we discuss recent observation of linear correlation on log-log scale between distribution of dark and visible mass in gravitationally bound systems. The coefficient of such correlation appears to be essentially the same for various systems of dramatically different scales such as spiral galaxies of different luminosities and galaxy clusters. We briefly touch possible interpretations of this observation and implications for the mass of dark matter particle.

astro-ph

Phenomenology of flavor oscillations with non-perturbative effects from quantum field theory

We analyze phenomenological aspects of the quantum field theoretical formulation of meson mixing and obtain the exact oscillation formula in the presence of the decay. This formula is different from quantum mechanical formula by additional high-frequency oscillation terms. In the infinite volume limit, the space of the flavor quantum states is unitarily inequivalent to the space of energy eigenstates.

hep-ph

Distribution of mass in galaxy cluster CL0024 and the particle mass of dark matter

We study in details the distribution of mass in galaxy cluster CL0024+1654 inferred using the method of strong gravitational lensing by Tyson {\it et al.} (1998). We show that a linear correlation exists between total, visible and dark matter distributions on log-log scale with consistent coefficients. The shape and parameters of log-log-linear correlation are not affected significantly whether one uses projected or volume mass densities but is consistent with $κ=2-5$ visible/dark ratio. We also show and analyze in depth so called alignment properties of the above-mentioned profiles. We show that log-log-linear correlation and alignments can all be understood in terms of thermodynamic/hydrodynamic equilibrium with gravitational potential growing almost linearly in the region of interest. We then analyze the hypothesis of thermal equilibrium on the base of the existing data about CL0024 cluster. If the presence of log-log-linear correlation and alignments were interpreted thermodynamically, this would indicate the mass of the dark matter particle 2-5 times smaller than that of atomic hydrogen, thus giving range for the mass of dark matter particle between 200MeV and 1000MeV.

astro-ph

Time-to-space conversion in quantum field theory of flavor mixing

We consider the problem of time-to-space conversion in quantum field theory of flavor mixing using a generalization of the wave-packet method in quantum mechanics. We work entirely within the canonical formalism of creation and annihilation operators that allows us, unlike the usual wave-packet formulation, to include the nontrivial effect due to flavor condensation in the vacuum.

hep-ph

Molar mass estimate of dark matter from the dark mass distribution measurements

We study the distribution of dark matter versus visible matter using a set of data obtained from strong gravitational lensing in the galaxy cluster CL0024+1654 and another set of data inferred from the universal rotation curves in spiral galaxies. The important feature of these two dramatically different observations is that the mass density profile of both visible and dark components can be estimated. From these measurements we deduce the mass of the dark matter particle and our estimate of the mass for the dark matter particle is $μ_d \approx (200-800)$MeV. We contrast our estimates from CL0024+1654 data and the universal rotation curves of the spiral galaxies and discuss their consistency.

astro-ph

The General Theory of Quantum Field Mixing

We present a general theory of mixing for an arbitrary number of fields with integer or half-integer spin. The time dynamics of the interacting fields is solved and the Fock space for interacting fields is explicitly constructed. The unitary inequivalence of the Fock space of base (unmixed) eigenstates and the physical mixed eigenstates is shown by a straightforward algebraic method for any number of flavors in boson or fermion statistics. The oscillation formulas based on the nonperturbative vacuum are derived in a unified general formulation and then applied to both two and three flavor cases. Especially, the mixing of spin-1 (vector) mesons and the CKM mixing phenomena in the Standard Model are discussed emphasizing the nonperturbative vacuum effect in quantum field theory.

hep-ph

Nonperturbative Vacuum Effect in the Quantum Field Theory of Meson Mixing

Replacing the perturbative vacuum by the nonperturbative vacuum, we extend a recent development of a quantum field theoretic framework for scalar and pseudoscalar meson mixing. The unitary inequivalence of the Fock space of base (unmixed) eigenstates and the physical mixed eigenstates is investigated and the flavor vacuum state structure is explicitly found. This is exploited to develop formulas for two flavor boson oscillations in systems of arbitrary boson occupation number. We apply these formulas to analyze the mixing of eta with eta' and comment on the other meson-mixing systems. In addition, we consider the mixing of boson coherent states, which may have future applications in the construction of meson lasers.

hep-ph