2,512 research outputs found
XMem++: Production-level Video Segmentation From Few Annotated Frames
Despite advancements in user-guided video segmentation, extracting complex
objects consistently for highly complex scenes is still a labor-intensive task,
especially for production. It is not uncommon that a majority of frames need to
be annotated. We introduce a novel semi-supervised video object segmentation
(SSVOS) model, XMem++, that improves existing memory-based models, with a
permanent memory module. Most existing methods focus on single frame
annotations, while our approach can effectively handle multiple user-selected
frames with varying appearances of the same object or region. Our method can
extract highly consistent results while keeping the required number of frame
annotations low. We further introduce an iterative and attention-based frame
suggestion mechanism, which computes the next best frame for annotation. Our
method is real-time and does not require retraining after each user input. We
also introduce a new dataset, PUMaVOS, which covers new challenging use cases
not found in previous benchmarks. We demonstrate SOTA performance on
challenging (partial and multi-class) segmentation scenarios as well as long
videos, while ensuring significantly fewer frame annotations than any existing
method. Project page: https://max810.github.io/xmem2-project-page/Comment: Accepted to ICCV 2023. 18 pages, 16 figure
Birthdating of myenteric neuron subtypes in the small intestine of the mouse
There are many different types of enteric neurons. Previous studies have identified the time at which some enteric neuron subtypes are born (exit the cell cycle) in the mouse, but the birthdates of some major enteric neuron subtypes are still incompletely characterized or unknown. We combined 5âethynynlâ2âČâdeoxyuridine (EdU) labeling with antibody markers that identify myenteric neuron subtypes to determine when neuron subtypes are born in the mouse small intestine. We found that different neurochemical classes of enteric neuron differed in their birthdates; serotonin neurons were born first with peak cell cycle exit at E11.5, followed by neurofilamentâM neurons, calcitonin geneârelated peptide neurons (peak cell cycle exit for both at embryonic day [E]12.5âE13.5), tyrosine hydroxylase neurons (E15.5), nitric oxide synthase 1 (NOS1) neurons (E15.5), and calretinin neurons (postnatal day [P]0). The vast majority of myenteric neurons had exited the cell cycle by P10. We did not observe any EdU+/NOS1+ myenteric neurons in the small intestine of adult mice following EdU injection at E10.5 or E11.5, which was unexpected, as previous studies have shown that NOS1 neurons are present in E11.5 mice. Studies using the proliferation marker Ki67 revealed that very few NOS1 neurons in the E11.5 and E12.5 gut were proliferating. However, Creâloxâbased genetic fateâmapping revealed a small subpopulation of myenteric neurons that appears to express NOS1 only transiently. Together, our results confirm a relationship between enteric neuron subtype and birthdate, and suggest that some enteric neurons exhibit neurochemical phenotypes during development that are different from their mature phenotype. J. Comp. Neurol. 522:514â527, 2014. © 2013 Wiley Periodicals, Inc. To examine when different myenteric neuron subtypes in the mouse intestine are born, EDU labeling was combined with immunohistochemistry. Neuron subtypes were born at different, but overlapping times with serotonin interneurons first, then intrinsic sensory neurons, inhibitory motor neurons and excitatory motor neurons last, with peak birthdate around birth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102151/1/cne23423.pd
Networked Estimation for Event-Based Sampling Systems with Packet Dropouts
This paper is concerned with a networked estimation problem in which sensor data are transmitted over the network. In the event-based sampling scheme known as level-crossing or send-on-delta (SOD), sensor data are transmitted to the estimator node if the difference between the current sensor value and the last transmitted one is greater than a given threshold. Event-based sampling has been shown to be more efficient than the time-triggered one in some situations, especially in network bandwidth improvement. However, it cannot detect packet dropout situations because data transmission and reception do not use a periodical time-stamp mechanism as found in time-triggered sampling systems. Motivated by this issue, we propose a modified event-based sampling scheme called modified SOD in which sensor data are sent when either the change of sensor output exceeds a given threshold or the time elapses more than a given interval. Through simulation results, we show that the proposed modified SOD sampling significantly improves estimation performance when packet dropouts happen
Manipulating Multiple Order Parameters via Oxygen Vacancies: The case of Eu0.5Ba0.5TiO3-{\delta}
Controlling functionalities, such as magnetism or ferroelectricity, by means
of oxygen vacancies (VO) is a key issue for the future development of
transition metal oxides. Progress in this field is currently addressed through
VO variations and their impact on mainly one order parameter. Here we reveal a
new mechanism for tuning both magnetism and ferroelectricity simultaneously by
using VO. Combined experimental and density-functional theory studies of
Eu0.5Ba0.5TiO3-{\delta}, we demonstrate that oxygen vacancies create Ti3+ 3d1
defect states, mediating the ferromagnetic coupling between the localized Eu
4f7 spins, and increase an off-center displacement of Ti ions, enhancing the
ferroelectric Curie temperature. The dual function of Ti sites also promises a
magnetoelectric coupling in the Eu0.5Ba0.5TiO3-{\delta}.Comment: Accepted by Physical Review B, 201
Prediction of contact angle for hydrophobic surface fabricated with micro-machining based on minimum Gibbs free energy
Linear Magnetoelectric Phase in Ultrathin MnPSâ Probed by Optical Second Harmonic Generation
The transition metal thiophosphates MPSâ (M=Mn, Fe, Ni) are a class of van der Waals stacked insulating antiferromagnets that can be exfoliated down to the ultrathin limit. MnPSâ is particularly interesting because its NĂ©el ordered state breaks both spatial-inversion and time-reversal symmetries, allowing for a linear magnetoelectric phase that is rare among van der Waals materials. However, it is unknown whether this unique magnetic structure of bulk MnPSâ remains stable in the ultrathin limit. Using optical second harmonic generation rotational anisotropy, we show that long-range linear magnetoelectric type NĂ©el order in MnPSâ persists down to at least 5.3 nm thickness. However an unusual mirror symmetry breaking develops in ultrathin samples on SiOâ substrates that is absent in bulk materials, which is likely related to substrate induced strain
Cosmological Constraints on the Modified Entropic Force Model
Very recently, Verlinde considered a theory in which space is emergent
through a holographic scenario, and proposed that gravity can be explained as
an entropic force caused by changes in the information associated with the
positions of material bodies. Then, motivated by the Debye model in
thermodynamics which is very successful in very low temperatures, Gao modified
the entropic force scenario. The modified entropic force (MEF) model is in fact
a modified gravity model, and the universe can be accelerated without dark
energy. In the present work, we consider the cosmological constraints on the
MEF model, and successfully constrain the model parameters to a narrow range.
We also discuss many other issues of the MEF model. In particular, we clearly
reveal the implicit root to accelerate the universe in the MEF model.Comment: 16 pages, 7 figures, revtex4; v2: discussions added, Phys. Lett. B in
press; v3: published versio
Phonon-assisted inter-valley scattering determines ultrafast exciton dynamics in MoSe bilayers
While valleys (energy extrema) are present in all band structures of solids,
their preeminent role in determining exciton resonances and dynamics in
atomically thin transition metal dichalcogenides (TMDC) is unique. Using
two-dimensional coherent electronic spectroscopy, we find that exciton
decoherence occurs on a much faster time scale in MoSe bilayers than that
in the monolayers. We further identify two population relaxation channels in
the bilayer, a coherent and an incoherent one. Our microscopic model reveals
that phonon-emission processes facilitate scattering events from the valley
to other lower energy and valleys in the bilayer. Our
combined experimental and theoretical studies unequivocally establish different
microscopic mechanisms that determine exciton quantum dynamics in TMDC
monolayers and bilayers. Understanding exciton quantum dynamics provides
critical guidance to manipulation of spin/valley degrees of freedom in TMDC
bilayers.Comment: 6 pages, 4 figure
- âŠ