136 research outputs found
Borderline Aggregation Kinetics in ``Dry'' and ``Wet'' Environments
We investigate the kinetics of constant-kernel aggregation which is augmented
by either: (a) evaporation of monomers from finite-mass clusters, or (b)
continuous cluster growth -- \ie, condensation. The rate equations for these
two processes are analyzed using both exact and asymptotic methods. In
aggregation-evaporation, if the evaporation is mass conserving, \ie, the
monomers which evaporate remain in the system and continue to be reactive, the
competition between evaporation and aggregation leads to several asymptotic
outcomes. For weak evaporation, the kinetics is similar to that of aggregation
with no evaporation, while equilibrium is quickly reached in the opposite case.
At a critical evaporation rate, the cluster mass distribution decays as
, where is the mass, while the typical cluster mass grows with
time as . In aggregation-condensation, we consider the process with a
growth rate for clusters of mass , , which is: (i) independent of ,
(ii) proportional to , and (iii) proportional to , with . In
the first case, the mass distribution attains a conventional scaling form, but
with the typical cluster mass growing as . When , the
typical mass grows exponentially in time, while the mass distribution again
scales. In the intermediate case of , scaling generally
applies, with the typical mass growing as . We also give an
exact solution for the linear growth model, , in one dimension.Comment: plain TeX, 17 pages, no figures, macro file prepende
Optimization in a Self-Stabilizing Service Discovery Framework for Large Scale Systems
Ability to find and get services is a key requirement in the development of large-scale distributed sys- tems. We consider dynamic and unstable environments, namely Peer-to-Peer (P2P) systems. In previous work, we designed a service discovery solution called Distributed Lexicographic Placement Table (DLPT), based on a hierar- chical overlay structure. A self-stabilizing version was given using the Propagation of Information with Feedback (PIF) paradigm. In this paper, we introduce the self-stabilizing COPIF (for Collaborative PIF) scheme. An algo- rithm is provided with its correctness proof. We use this approach to improve a distributed P2P framework designed for the services discovery. Significantly efficient experimental results are presented
Developmental Exposure to a Commercial PBDE Mixture: Effects on Protein Networks in the Cerebellum and Hippocampus of Rats
Background: Polybrominated diphenyl ethers (PBDEs) are structurally similar to polychlorinated biphenyls (PCBs) and have both central (learning and memory deficits) and peripheral (motor dysfunction) neurotoxic effects at concentrations/doses similar to those of PCBs. The cellular and molecular mechanisms for these neurotoxic effects are not fully understood; however, several studies have shown that PBDEs affect thyroid hormones, cause oxidative stress, and disrupt Ca2+-mediated signal transduction. Changes in these signal transduction pathways can lead to differential gene regulation with subsequent changes in protein expression, which can affect the development and function of the nervous system
Google USM: Scaling Automatic Speech Recognition Beyond 100 Languages
We introduce the Universal Speech Model (USM), a single large model that
performs automatic speech recognition (ASR) across 100+ languages. This is
achieved by pre-training the encoder of the model on a large unlabeled
multilingual dataset of 12 million (M) hours spanning over 300 languages, and
fine-tuning on a smaller labeled dataset. We use multilingual pre-training with
random-projection quantization and speech-text modality matching to achieve
state-of-the-art performance on downstream multilingual ASR and speech-to-text
translation tasks. We also demonstrate that despite using a labeled training
set 1/7-th the size of that used for the Whisper model, our model exhibits
comparable or better performance on both in-domain and out-of-domain speech
recognition tasks across many languages.Comment: 20 pages, 7 figures, 8 table
BigSSL: Exploring the Frontier of Large-Scale Semi-Supervised Learning for Automatic Speech Recognition
We summarize the results of a host of efforts using giant automatic speech
recognition (ASR) models pre-trained using large, diverse unlabeled datasets
containing approximately a million hours of audio. We find that the combination
of pre-training, self-training and scaling up model size greatly increases data
efficiency, even for extremely large tasks with tens of thousands of hours of
labeled data. In particular, on an ASR task with 34k hours of labeled data, by
fine-tuning an 8 billion parameter pre-trained Conformer model we can match
state-of-the-art (SoTA) performance with only 3% of the training data and
significantly improve SoTA with the full training set. We also report on the
universal benefits gained from using big pre-trained and self-trained models
for a large set of downstream tasks that cover a wide range of speech domains
and span multiple orders of magnitudes of dataset sizes, including obtaining
SoTA performance on many public benchmarks. In addition, we utilize the learned
representation of pre-trained networks to achieve SoTA results on non-ASR
tasks.Comment: 14 pages, 7 figures, 13 tables; v2: minor corrections, reference
baselines and bibliography updated; v3: corrections based on reviewer
feedback, bibliography update
Stability and Control characteristics of MIG-21 aircraft
This document provides the stability and control derivatives
data for the MIG-21BIS aircraft in the form readily usable
for control system synthesis. Analytical prediction of the
aircraft modes, typical time responses as well as Bode plots
in the frequency domain are presented. Longitudinal dynamics data presented in this document supersedes the one provided in NAL PD SE 8501
Computation of the aerodynamic characteristics of wings in linearised supersonic flow
For the solution of tbe linearised supersonic flow equation, an explicit numerical scheme is discussed. Using this formulation,the aerodynamic characteristics of finite finite wings are coaputed based on lifting surface theory. Some results of the study of wing-fusalage configurations using this metbod are also given
A Computer programme for DATCOM methods of estimation of lateral stability and control derivatives
A computer code has been developed to estimate the lateral stability and control derivatives of aircraft configuration. The code, in general, is based on USAF DATCOM methods; in the case of a few derivatives, some approximate relations are used. The code estimates nine important lateral derivatives and five control derivatives. A brief review of the methods along with the limitations of DATCOM is presented. A comparison between the results of the code with those of the worked examples of DATCOM are given for some cases. Application of the code for typical configurations is discussed
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