Efficiency improvement of the frequency-domain BEM for rapid transient elastodynamic analysis

The frequency-domain fast boundary element method (BEM) combined with the exponential window technique leads to an efficient yet simple method for elastodynamic analysis. In this paper, the efficiency of this method is further enhanced by three strategies. Firstly, we propose to use exponential window with large damping parameter to improve the conditioning of the BEM matrices. Secondly, the frequency domain windowing technique is introduced to alleviate the severe Gibbs oscillations in time-domain responses caused by large damping parameters. Thirdly, a solution extrapolation scheme is applied to obtain better initial guesses for solving the sequential linear systems in the frequency domain. Numerical results of three typical examples with the problem size up to 0.7 million unknowns clearly show that the first and third strategies can significantly reduce the computational time. The second strategy can effectively eliminate the Gibbs oscillations and result in accurate time-domain responses

Momentum and Mass Fluxes in a Gas Confined between Periodically Structured Surfaces at Different Temperatures

It is well known that in a gas-filled duct or channel along which a temperature gradient is applied, a thermal creep flow is created. Here we show that a mass and momentum flux can also be induced in a gas confined between two parallel structured surfaces at different temperatures, i.e. \textit{orthogonal} to the temperature gradient. We use both analytical and numerical methods to compute the resulting fluxes. The momentum flux assumes its maximum value in the free-molecular flow regime, the (normalized) mass flux in the transition flow regime. The discovered phenomena could find applications in novel methods for energy-conversion and thermal pumping of gases.Comment: 6 pages, 5 figures, updated fig.5, updated text for the numerical metho

Parameter-Efficient Conformers via Sharing Sparsely-Gated Experts for End-to-End Speech Recognition

While transformers and their variant conformers show promising performance in speech recognition, the parameterized property leads to much memory cost during training and inference. Some works use cross-layer weight-sharing to reduce the parameters of the model. However, the inevitable loss of capacity harms the model performance. To address this issue, this paper proposes a parameter-efficient conformer via sharing sparsely-gated experts. Specifically, we use sparsely-gated mixture-of-experts (MoE) to extend the capacity of a conformer block without increasing computation. Then, the parameters of the grouped conformer blocks are shared so that the number of parameters is reduced. Next, to ensure the shared blocks with the flexibility of adapting representations at different levels, we design the MoE routers and normalization individually. Moreover, we use knowledge distillation to further improve the performance. Experimental results show that the proposed model achieves competitive performance with 1/3 of the parameters of the encoder, compared with the full-parameter model.Comment: accepted in INTERSPEECH 202

Światowa produktywność badań w dziedzinie endokrynologii i metabolizmu — analiza bibliometryczna

  Introduction: Recently, significant contributions to the study of endocrinology and metabolism have been made. The national contribution, however, has not been reported. The aim of this study was to assess national efforts in the field of endocrinology and metabolism. Material and methods: A Web of Science search was performed using subject categories “endocrinology & metabolism” to identify articles published from 2010 to 2014. The total and per capita numbers of articles and citations were analysed for different countries. Results: A total of 79,394 articles were published on endocrinology and metabolism from 2010 to 2014. Most were published in North America, East Asia, and Europe. The majority (82.28%) were reported by authors in high-income countries, 17.64% were published in middle-income countries, and only 0.08% were published in low-income countries. Authors in the United States published the most articles (27.38%), followed by China (7.22%), Italy (5.70%), the United Kingdom (5.6%), and Japan (5.54%). Articles published by authors in the United States had the most citations (260,934). A positive correlation was found between the number of publications and population/gross domestic product (GDP; p < 0.01). When normalised to population size, the ranking for the most publications was Denmark, Sweden, and the Netherlands; when normalised to GDP, the ranking was Denmark, Greece, and the Netherlands. Conclusions: The majority of endocrinology and metabolism articles were published by authors from high-income countries with few from low-income countries. The United States was the most productive country. However, when population size and GDP were considered, some European countries were ranked higher. (Endokrynol Pol 2015; 66 (5): 434–442)    Wstęp: Ostatnio pojawiło się wiele znaczących publikacji na temat badań z dziedziny endokrynologii i metabolizmu. Narodowy wkład na tym polu został jednak pominięty. Celem niniejszego badania była ocena krajowych badań w dziedzinie endokrynologii i metabolizmu. Materiał i metody: Wyszukiwanie za pomocą Web of Science przeprowadzono z wykorzystaniem kategorii podmiotowych „endokrynologia i metabolizm”, aby zidentyfikować artykuły opublikowane w latach 2010–2014. Analizie poddano łączną liczbę artykułów i cytowań, a także ich liczbę przypadającą na osobę w odniesieniu do różnych krajów. Wyniki: W latach 2010–2014 opublikowano łącznie 79 394 artykułów na temat endokrynologii i metabolizmu. Większość artykułów pochodziła z Ameryki Północnej, Azji Wschodniej i Europy. Większość artykułów (82,28%) napisali autorzy z krajów o wysokich dochodach, 17,64% opublikowano w krajach średnio zamożnych, a jedynie 0,08% artykułów opublikowano w krajach o niskich dochodach. Najwięcej artykułów publikowali autorzy ze Stanów Zjednoczonych (27,38%), następnie z Chin (7,22%), Włoch (5,70%), Wielkiej Brytanii (5,6%) i Japonii (5,54%). Prace publikowane przez amerykańskich autorów zawierały największą liczbę cytowań (260 934). Stwierdzono pozytywny związek między liczbą publikacji i populacją/produktem krajowym brutto (PKB; p < 0,01). Po unormalizowaniu do liczebności populacji, w rankingu krajów o najwyższej liczbie publikacji znalazły się Dania, Szwecja oraz Holandia. Gdy znormalizowano wyniki pod względem PKB, w rankingu znalazły się Dania, Grecja oraz Holandia. Wnioski: Większość artykułów z dziedziny endokrynologii i metabolizmu została opublikowana przez autorów z krajów o wysokich dochodach; w krajach o niskich dochodach ukazało się niewiele artykułów. Stany Zjednoczone wykazały największą produktywność, jednak kiedy brano pod uwagę liczebność populacji i PKB, niektóre kraje europejskie zajmowały wyższą pozycję. (Endokrynol Pol 2015; 66 (5): 434–442)