76 research outputs found
Audio Time-Scale Modification with Temporal Compressing Networks
We proposed a novel approach in the field of time-scale modification on audio
signals. While traditional methods use the framing technique, spectral approach
uses the short-time Fourier transform to preserve the frequency during temporal
stretching. TSM-Net, our neural-network model encodes the raw audio into a
high-level latent representation. We call it Neuralgram, in which one vector
represents 1024 audio samples. It is inspired by the framing technique but
addresses the clipping artifacts. The Neuralgram is a two-dimensional matrix
with real values, we can apply some existing image resizing techniques on the
Neuralgram and decode it using our neural decoder to obtain the time-scaled
audio. Both the encoder and decoder are trained with GANs, which shows fair
generalization ability on the scaled Neuralgrams. Our method yields little
artifacts and opens a new possibility in the research of modern time-scale
modification. The audio samples can be found on
https://ernestchu.github.io/tsm-net-demo
Video ControlNet: Towards Temporally Consistent Synthetic-to-Real Video Translation Using Conditional Image Diffusion Models
In this study, we present an efficient and effective approach for achieving
temporally consistent synthetic-to-real video translation in videos of varying
lengths. Our method leverages off-the-shelf conditional image diffusion models,
allowing us to perform multiple synthetic-to-real image generations in
parallel. By utilizing the available optical flow information from the
synthetic videos, our approach seamlessly enforces temporal consistency among
corresponding pixels across frames. This is achieved through joint noise
optimization, effectively minimizing spatial and temporal discrepancies. To the
best of our knowledge, our proposed method is the first to accomplish diverse
and temporally consistent synthetic-to-real video translation using conditional
image diffusion models. Furthermore, our approach does not require any training
or fine-tuning of the diffusion models. Extensive experiments conducted on
various benchmarks for synthetic-to-real video translation demonstrate the
effectiveness of our approach, both quantitatively and qualitatively. Finally,
we show that our method outperforms other baseline methods in terms of both
temporal consistency and visual quality
MeDM: Mediating Image Diffusion Models for Video-to-Video Translation with Temporal Correspondence Guidance
This study introduces an efficient and effective method, MeDM, that utilizes
pre-trained image Diffusion Models for video-to-video translation with
consistent temporal flow. The proposed framework can render videos from scene
position information, such as a normal G-buffer, or perform text-guided editing
on videos captured in real-world scenarios. We employ explicit optical flows to
construct a practical coding that enforces physical constraints on generated
frames and mediates independent frame-wise scores. By leveraging this coding,
maintaining temporal consistency in the generated videos can be framed as an
optimization problem with a closed-form solution. To ensure compatibility with
Stable Diffusion, we also suggest a workaround for modifying observed-space
scores in latent-space Diffusion Models. Notably, MeDM does not require
fine-tuning or test-time optimization of the Diffusion Models. Through
extensive qualitative, quantitative, and subjective experiments on various
benchmarks, the study demonstrates the effectiveness and superiority of the
proposed approach
Deep Complex U-Net with Conformer for Audio-Visual Speech Enhancement
Recent studies have increasingly acknowledged the advantages of incorporating
visual data into speech enhancement (SE) systems. In this paper, we introduce a
novel audio-visual SE approach, termed DCUC-Net (deep complex U-Net with
conformer network). The proposed DCUC-Net leverages complex domain features and
a stack of conformer blocks. The encoder and decoder of DCUC-Net are designed
using a complex U-Net-based framework. The audio and visual signals are
processed using a complex encoder and a ResNet-18 model, respectively. These
processed signals are then fused using the conformer blocks and transformed
into enhanced speech waveforms via a complex decoder. The conformer blocks
consist of a combination of self-attention mechanisms and convolutional
operations, enabling DCUC-Net to effectively capture both global and local
audio-visual dependencies. Our experimental results demonstrate the
effectiveness of DCUC-Net, as it outperforms the baseline model from the
COG-MHEAR AVSE Challenge 2023 by a notable margin of 0.14 in terms of PESQ.
Additionally, the proposed DCUC-Net performs comparably to a state-of-the-art
model and outperforms all other compared models on the Taiwan Mandarin speech
with video (TMSV) dataset
Examples of complete solvability of 2D classical superintegrable systems
Classical (maximal) superintegrable systems in n dimensions are Hamiltonian systems with 2n - 1 independent constants of the motion, globally defined, the maximum number possible. They are very special because they can be solved algebraically. In this paper we show explicitly, mostly through examples of 2nd order superintegrable systems in 2 dimensions, how the trajectories can be determined in detail using rather elementary algebraic, geometric and analytic methods applied to the closed quadratic algebra of symmetries of the system, without resorting to separation of variables techniques or trying to integrate Hamilton’s equations. We treat a family of 2nd order degenerate systems: oscillator analogies on Darboux, nonzero constant curvature, and flat spaces, related to one another via contractions, and obeying Kepler’s laws. Then we treat two 2nd order nondegenerate systems, an analogy of a caged Coulomb problem on the 2-sphere and its contraction to a Euclidean space caged Coulomb problem. In all cases the symmetry algebra structure provides detailed information about the trajectories, some of which are rather complicated. An interesting example is the occurrence of “metronome orbits”, trajectories confined to an arc rather than a loop, which are indicated clearly from the structure equations but might be overlooked using more traditional methods. We also treat the Post-Winternitz system, an example of a classical 4th order superintegrable system that cannot be solved using separation of variables. Finally we treat a superintegrable system, related to the addition theorem for elliptic functions, whose constants of the motion are only rational in the momenta. It is a system of special interest because its constants of the motion generate a closed polynomial algebra. This paper contains many new results but we have tried to present most of the materials in a fashion that is easily accessible to nonexperts, in order to provide entrée to superintegrablity theory
Concept for a Future Super Proton-Proton Collider
Following the discovery of the Higgs boson at LHC, new large colliders are
being studied by the international high-energy community to explore Higgs
physics in detail and new physics beyond the Standard Model. In China, a
two-stage circular collider project CEPC-SPPC is proposed, with the first stage
CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on
Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused
on new physics beyond the Standard Model. This paper discusses this second
stage.Comment: 34 pages, 8 figures, 5 table
Best practice data standards for discrete chemical oceanographic observations
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Jiang, L.-Q., Pierrot, D., Wanninkhof, R., Feely, R. A., Tilbrook, B., Alin, S., Barbero, L., Byrne, R. H., Carter, B. R., Dickson, A. G., Gattuso, J.-P., Greeley, D., Hoppema, M., Humphreys, M. P., Karstensen, J., Lange, N., Lauvset, S. K., Lewis, E. R., Olsen, A., Pérez, F. F., Sabine, C., Sharp, J. D., Tanhua, T., Trull, T. W., Velo, A., Allegra, A. J., Barker, P., Burger, E., Cai, W-J., Chen, C-T. A., Cross, J., Garcia, H., Hernandez-Ayon J. M., Hu, X., Kozyr, A., Langdon, C., Lee., K, Salisbury, J., Wang, Z. A., & Xue, L. Best practice data standards for discrete chemical oceanographic observations. Frontiers in Marine Science, 8, (2022): 705638, https://doi.org/10.3389/fmars.2021.705638.Effective data management plays a key role in oceanographic research as cruise-based data, collected from different laboratories and expeditions, are commonly compiled to investigate regional to global oceanographic processes. Here we describe new and updated best practice data standards for discrete chemical oceanographic observations, specifically those dealing with column header abbreviations, quality control flags, missing value indicators, and standardized calculation of certain properties. These data standards have been developed with the goals of improving the current practices of the scientific community and promoting their international usage. These guidelines are intended to standardize data files for data sharing and submission into permanent archives. They will facilitate future quality control and synthesis efforts and lead to better data interpretation. In turn, this will promote research in ocean biogeochemistry, such as studies of carbon cycling and ocean acidification, on regional to global scales. These best practice standards are not mandatory. Agencies, institutes, universities, or research vessels can continue using different data standards if it is important for them to maintain historical consistency. However, it is hoped that they will be adopted as widely as possible to facilitate consistency and to achieve the goals stated above.Funding for L-QJ and AK was from NOAA Ocean Acidification Program (OAP, Project ID: 21047) and NOAA National Centers for Environmental Information (NCEI) through NOAA grant NA19NES4320002 [Cooperative Institute for Satellite Earth System Studies (CISESS)] at the University of Maryland/ESSIC. BT was in part supported by the Australia’s Integrated Marine Observing System (IMOS), enabled through the National Collaborative Research Infrastructure Strategy (NCRIS). AD was supported in part by the United States National Science Foundation. AV and FP were supported by BOCATS2 Project (PID2019-104279GB-C21/AEI/10.13039/501100011033) funded by the Spanish Research Agency and contributing to WATER:iOS CSIC interdisciplinary thematic platform. MH was partly funded by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement N°821001 (SO-CHIC)
Electron transfer kinetics on natural crystals of MoS2 and graphite
Here, we evaluate the electrochemical performance of sparsely studied natural crystals of molybdenite and graphite, which have increasingly been used for fabrication of next generation monolayer molybdenum disulphide and graphene energy storage devices. Heterogeneous electron transfer kinetics of several redox mediators, including Fe(CN)63−/4−, Ru(NH3)63+/2+ and IrCl62−/3− are determined using voltammetry in a micro-droplet cell. The kinetics on both materials are studied as a function of surface defectiveness, surface ageing, applied potential and illumination. We find that the basal planes of both natural MoS2 and graphite show significant electroactivity, but a large decrease in electron transfer kinetics is observed on atmosphere-aged surfaces in comparison to in situ freshly cleaved surfaces of both materials. This is attributed to surface oxidation and adsorption of airborne contaminants at the surface exposed to an ambient environment. In contrast to semimetallic graphite, the electrode kinetics on semiconducting MoS2 are strongly dependent on the surface illumination and applied potential. Furthermore, while visibly present defects/cracks do not significantly affect the response of graphite, the kinetics on MoS2 systematically accelerate with small increase in disorder. These findings have direct implications for use of MoS2 and graphene/graphite as electrode materials in electrochemistry-related applications
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
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