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Contrasting size-resolved hygroscopicity of fine particles derived by HTDMA and HR-ToF-AMS measurements between summer and winter in Beijing: the impacts of aerosol aging and local emissions
Recognizing Voice Over IP: A Robust Front-End for Speech Recognition on the World Wide Web
The Internet Protocol (IP) environment poses two relevant sources of distortion to the speech recognition problem: lossy speech coding and packet loss. In this paper, we propose a new front-end for speech recognition over IP networks. Specifically, we suggest extracting the recognition feature vectors directly from the encoded speech (i.e., the bit stream) instead of decoding it and subsequently extracting the feature vectors. This approach offers two significant benefits. First, the recognition system is only affected by the quantization distortion of the spectral envelope. Thus, we are avoiding the influence of other sources of distortion due to the encoding-decoding process. Second, when packet loss occurs, our front-end becomes more effective since it is not constrained to the error handling mechanism of the codec. We have considered the ITU G.723.1 standard codec, which is one of the most preponderant coding algorithms in voice over IP (VoIP) and compared the proposed front-end with the conventional approach in two automatic speech recognition (ASR) tasks, namely, speaker-independent isolated digit recognition and speaker-independent continuous speech recognition. In general, our approach outperforms the conventional procedure, for a variety of simulated packet loss rates. Furthermore, the improvement is higher as network conditions worsen.Publicad
The Potential Importance of Non-Local, Deep Transport on the Energetics, Momentum, Chemistry, and Aerosol Distributions in the Atmospheres of Earth, Mars and Titan
A review of non-local, deep transport mechanisms in the atmosphere of Earth
provides a good foundation for examining whether similar mechanisms are
operating in the atmospheres of Mars and Titan. On Earth, deep convective
clouds in the tropics constitute the upward branch of the Hadley Cell and
provide a conduit through which energy, moisture, momentum, aerosols and
chemical species are moved from the boundary layer to the upper troposphere and
lower stratosphere. This transport produces mid-tropospheric minima in
quantities such as water vapor and moist static energy and maxima where the
clouds detrain. Analogs to this terrestrial transport are found in the strong
and deep thermal circulations associated with topography on Mars and with Mars
dust storms. Observations of elevated dust layers on Mars further support the
notion that non-local deep transport is an important mechanism in the
atmosphere of Mars. On Titan, the presence of deep convective clouds almost
assures that non-local, deep transport is occurring and these clouds may play a
role in global cycling of energy, momentum, and methane. Based on the potential
importance of non-local deep transport in Earth's atmosphere and supported by
evidence for such transport in the atmospheres of Mars and Titan, greater
attention to this mechanism in extraterrestrial atmospheres is warranted.Comment: 25 pages, no figures, no table
5G 3GPP-like Channel Models for Outdoor Urban Microcellular and Macrocellular Environments
For the development of new 5G systems to operate in bands up to 100 GHz,
there is a need for accurate radio propagation models at these bands that
currently are not addressed by existing channel models developed for bands
below 6 GHz. This document presents a preliminary overview of 5G channel models
for bands up to 100 GHz. These have been derived based on extensive measurement
and ray tracing results across a multitude of frequencies from 6 GHz to 100
GHz, and this document describes an initial 3D channel model which includes: 1)
typical deployment scenarios for urban microcells (UMi) and urban macrocells
(UMa), and 2) a baseline model for incorporating path loss, shadow fading, line
of sight probability, penetration and blockage models for the typical
scenarios. Various processing methodologies such as clustering and antenna
decoupling algorithms are also presented.Comment: To be published in 2016 IEEE 83rd Vehicular Technology Conference
Spring (VTC 2016-Spring), Nanjing, China, May 201
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