4,119 research outputs found
The Primary Study on Evaluating Index System of Energy Efficient Buildings
In the standards and criterions of many countries, the evaluating index of energy efficient buildings mostly comprises of two types, prescriptive index and performance index. Firstly , the concepts of each type were explained respectively in this paper , and several existed typical evaluating performance indexes and methods of energy2efficient buildings were introduced , also the characteristics of each index were presented. Furthermore , the evaluating indexes and methods used by existing design standards for energy efficiency buildings in China were briefly discussed and some elementary suggestions on the foundation of evaluating index system were analyzed. At last , based on the discussion , a suitable evaluating index system of energy efficient buildings for China could be established , as a result , the energy resources could be saved and the environment could be protected
Long-frame-shift Neural Speech Phase Prediction with Spectral Continuity Enhancement and Interpolation Error Compensation
Speech phase prediction, which is a significant research focus in the field
of signal processing, aims to recover speech phase spectra from
amplitude-related features. However, existing speech phase prediction methods
are constrained to recovering phase spectra with short frame shifts, which are
considerably smaller than the theoretical upper bound required for exact
waveform reconstruction of short-time Fourier transform (STFT). To tackle this
issue, we present a novel long-frame-shift neural speech phase prediction
(LFS-NSPP) method which enables precise prediction of long-frame-shift phase
spectra from long-frame-shift log amplitude spectra. The proposed method
consists of three stages: interpolation, prediction and decimation. The
short-frame-shift log amplitude spectra are first constructed from
long-frame-shift ones through frequency-by-frequency interpolation to enhance
the spectral continuity, and then employed to predict short-frame-shift phase
spectra using an NSPP model, thereby compensating for interpolation errors.
Ultimately, the long-frame-shift phase spectra are obtained from
short-frame-shift ones through frame-by-frame decimation. Experimental results
show that the proposed LFS-NSPP method can yield superior quality in predicting
long-frame-shift phase spectra than the original NSPP model and other
signal-processing-based phase estimation algorithms.Comment: Published at IEEE Signal Processing Letter
Source-Filter-Based Generative Adversarial Neural Vocoder for High Fidelity Speech Synthesis
This paper proposes a source-filter-based generative adversarial neural
vocoder named SF-GAN, which achieves high-fidelity waveform generation from
input acoustic features by introducing F0-based source excitation signals to a
neural filter framework. The SF-GAN vocoder is composed of a source module and
a resolution-wise conditional filter module and is trained based on generative
adversarial strategies. The source module produces an excitation signal from
the F0 information, then the resolution-wise convolutional filter module
combines the excitation signal with processed acoustic features at various
temporal resolutions and finally reconstructs the raw waveform. The
experimental results show that our proposed SF-GAN vocoder outperforms the
state-of-the-art HiFi-GAN and Fre-GAN in both analysis-synthesis (AS) and
text-to-speech (TTS) tasks, and the synthesized speech quality of SF-GAN is
comparable to the ground-truth audio.Comment: Accepted by NCMMSC 202
Explicit Estimation of Magnitude and Phase Spectra in Parallel for High-Quality Speech Enhancement
Phase information has a significant impact on speech perceptual quality and
intelligibility. However, existing speech enhancement methods encounter
limitations in explicit phase estimation due to the non-structural nature and
wrapping characteristics of the phase, leading to a bottleneck in enhanced
speech quality. To overcome the above issue, in this paper, we proposed
MP-SENet, a novel Speech Enhancement Network which explicitly enhances
Magnitude and Phase spectra in parallel. The proposed MP-SENet adopts a codec
architecture in which the encoder and decoder are bridged by time-frequency
Transformers along both time and frequency dimensions. The encoder aims to
encode time-frequency representations derived from the input distorted
magnitude and phase spectra. The decoder comprises dual-stream magnitude and
phase decoders, directly enhancing magnitude and wrapped phase spectra by
incorporating a magnitude estimation architecture and a phase parallel
estimation architecture, respectively. To train the MP-SENet model effectively,
we define multi-level loss functions, including mean square error and
perceptual metric loss of magnitude spectra, anti-wrapping loss of phase
spectra, as well as mean square error and consistency loss of short-time
complex spectra. Experimental results demonstrate that our proposed MP-SENet
excels in high-quality speech enhancement across multiple tasks, including
speech denoising, dereverberation, and bandwidth extension. Compared to
existing phase-aware speech enhancement methods, it successfully avoids the
bidirectional compensation effect between the magnitude and phase, leading to a
better harmonic restoration. Notably, for the speech denoising task, the
MP-SENet yields a state-of-the-art performance with a PESQ of 3.60 on the
public VoiceBank+DEMAND dataset.Comment: Submmited to IEEE Transactions on Audio, Speech and Language
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2-(2-Chloropyrimidin-4-yl)-3,5,6,7,8,9-hexahydro-2H-1,2,4-triazolo[4,3-a]azepin-3-one
In the title compound, C11H12ClN5O, the triazolone and pyrimidine rings are almost coplanar [dihedral angle = 2.98 (14)°]. The total puckering amplitude QT of the seven-membered lactam ring is 0.706 (3) Å
APNet2: High-quality and High-efficiency Neural Vocoder with Direct Prediction of Amplitude and Phase Spectra
In our previous work, we proposed a neural vocoder called APNet, which
directly predicts speech amplitude and phase spectra with a 5 ms frame shift in
parallel from the input acoustic features, and then reconstructs the 16 kHz
speech waveform using inverse short-time Fourier transform (ISTFT). APNet
demonstrates the capability to generate synthesized speech of comparable
quality to the HiFi-GAN vocoder but with a considerably improved inference
speed. However, the performance of the APNet vocoder is constrained by the
waveform sampling rate and spectral frame shift, limiting its practicality for
high-quality speech synthesis. Therefore, this paper proposes an improved
iteration of APNet, named APNet2. The proposed APNet2 vocoder adopts ConvNeXt
v2 as the backbone network for amplitude and phase predictions, expecting to
enhance the modeling capability. Additionally, we introduce a multi-resolution
discriminator (MRD) into the GAN-based losses and optimize the form of certain
losses. At a common configuration with a waveform sampling rate of 22.05 kHz
and spectral frame shift of 256 points (i.e., approximately 11.6ms), our
proposed APNet2 vocoder outperformed the original APNet and Vocos vocoders in
terms of synthesized speech quality. The synthesized speech quality of APNet2
is also comparable to that of HiFi-GAN and iSTFTNet, while offering a
significantly faster inference speed
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Genetic Association Study with Metabolic Syndrome and Metabolic-Related Traits in a Cross-Sectional Sample and a 10-Year Longitudinal Sample of Chinese Elderly Population
Background: The metabolic syndrome (MetS) has been known as partly heritable, while the number of genetic studies on MetS and metabolic-related traits among Chinese elderly was limited. Methods: A cross-sectional analysis was performed among 2 014 aged participants from September 2009 to June 2010 in Beijing, China. An additional longitudinal study was carried out among the same study population from 2001 to 2010. Biochemical profile and anthropometric parameters of all the participants were measured. The associations of 23 SNPs located within 17 candidate genes (MTHFR, PPARγ, LPL, INSIG, TCF7L2, FTO, KCNJ11, JAZF1, CDKN2A/B, ADIPOQ, WFS1, CDKAL1, IGF2BP2, KCNQ1, MTNR1B, IRS1, ACE) with overweight and obesity, diabetes, metabolic phenotypes, and MetS were examined in both studies. Results: In this Chinese elderly population, prevalence of overweight, central obesity, diabetes, dyslipidemia, hypertension, and MetS were 48.3%, 71.0%, 32.4%, 75.7%, 68.3% and 54.5%, respectively. In the cross-sectional analyses, no SNP was found to be associated with MetS. Genotype TT of SNP rs4402960 within the gene IGF2BP2 was associated with overweight (odds ratio (OR) = 0.479, 95% confidence interval (CI): 0.316-0.724, p = 0.001) and genotype CA of SNP rs1801131 within the gene MTHFR was associated with hypertension (OR = 1.560, 95% CI: 1.194–2.240, p = 0.001). However, these associations were not observed in the longitudinal analyses. Conclusions: The associations of SNP rs4402960 with overweight as well as the association of SNP rs1801131 with hypertension were found to be statistically significant. No SNP was identified to be associated with MetS in our study with statistical significance
Generation of Oligodendrocyte Progenitor Cells From Mouse Bone Marrow Cells.
Oligodendrocyte progenitor cells (OPCs) are a subtype of glial cells responsible for myelin regeneration. Oligodendrocytes (OLGs) originate from OPCs and are the myelinating cells in the central nervous system (CNS). OLGs play an important role in the context of lesions in which myelin loss occurs. Even though many protocols for isolating OPCs have been published, their cellular yield remains a limit for clinical application. The protocol proposed here is novel and has practical value; in fact, OPCs can be generated from a source of autologous cells without gene manipulation. Our method represents a rapid, and high-efficiency differentiation protocol for generating mouse OLGs from bone marrow-derived cells using growth-factor defined media. With this protocol, it is possible to obtain mature OLGs in 7-8 weeks. Within 2-3 weeks from bone marrow (BM) isolation, after neurospheres formed, the cells differentiate into Nestin+ Sox2+ neural stem cells (NSCs), around 30 days. OPCs specific markers start to be expressed around day 38, followed by RIP+O4+ around day 42. CNPase+ mature OLGs are finally obtained around 7-8 weeks. Further, bone marrow-derived OPCs exhibited therapeutic effect in shiverer (Shi) mice, promoting myelin regeneration and reducing the tremor. Here, we propose a method by which OLGs can be generated starting from BM cells and have similar abilities to subventricular zone (SVZ)-derived cells. This protocol significantly decreases the timing and costs of the OLGs differentiation within 2 months of culture
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