984 research outputs found
Spin tunneling properties in mesoscopic magnets: effects of a magnetic field
The tunneling of a giant spin at excited levels is studied theoretically in
mesoscopic magnets with a magnetic field at an arbitrary angle in the easy
plane. Different structures of the tunneling barriers can be generated by the
magnetocrystalline anisotropy, the magnitude and the orientation of the field.
By calculating the nonvacuum instanton solution explicitly, we obtain the
tunnel splittings and the tunneling rates for different angle ranges of the
external magnetic field ( and ). The
temperature dependences of the decay rates are clearly shown for each case. It
is found that the tunneling rate and the crossover temperature depend on the
orientation of the external magnetic field. This feature can be tested with the
use of existing experimental techniques.Comment: 27 pages, 4 figures, accepted by Euro. Phys. J.
Context-Aware Telco Outdoor Localization
Recent years have witnessed the fast growth in telecommunication (Telco) techniques from 2G to upcoming 5G. Precise outdoor localization is important for Telco operators to manage, operate and optimize Telco networks. Differing from GPS, Telco localization is a technique employed by Telco operators to localize outdoor mobile devices by using measurement report (MR) data. When given MR samples containing noisy signals (e.g., caused by Telco signal interference and attenuation), Telco localization often suffers from high errors. To this end, the main focus of this paper is how to improve Telco localization accuracy via the algorithms to detect and repair outlier positions with high errors. Specifically, we propose a context-aware Telco localization technique, namely RLoc, which consists of three main components: a machine-learning-based localization algorithm, a detection algorithm to find flawed samples, and a repair algorithm to replace outlier localization results by better ones (ideally ground truth positions). Unlike most existing works to detect and repair every flawed MR sample independently, we instead take into account spatio-temporal locality of MR locations and exploit trajectory context to detect and repair flawed positions. Our experiments on the real MR data sets from 2G GSM and 4G LTE Telco networks verify that our work RLoc can greatly improve Telco location accuracy. For example, RLoc on a large 4G MR data set can achieve 32.2 meters of median errors, around 17.4 percent better than state-of-the-art.Peer reviewe
Graftâ Free Maxillary Sinus Floor Elevation: A Systematic Review and Metaâ Analysis
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141088/1/jper0550.pd
SDF-Pack: Towards Compact Bin Packing with Signed-Distance-Field Minimization
Robotic bin packing is very challenging, especially when considering
practical needs such as object variety and packing compactness. This paper
presents SDF-Pack, a new approach based on signed distance field (SDF) to model
the geometric condition of objects in a container and compute the object
placement locations and packing orders for achieving a more compact bin
packing. Our method adopts a truncated SDF representation to localize the
computation, and based on it, we formulate the SDF minimization heuristic to
find optimized placements to compactly pack objects with the existing ones. To
further improve space utilization, if the packing sequence is controllable, our
method can suggest which object to be packed next. Experimental results on a
large variety of everyday objects show that our method can consistently achieve
higher packing compactness over 1,000 packing cases, enabling us to pack more
objects into the container, compared with the existing heuristics under various
packing settings
A Four-Stage Data Augmentation Approach to ResNet-Conformer Based Acoustic Modeling for Sound Event Localization and Detection
In this paper, we propose a novel four-stage data augmentation approach to
ResNet-Conformer based acoustic modeling for sound event localization and
detection (SELD). First, we explore two spatial augmentation techniques, namely
audio channel swapping (ACS) and multi-channel simulation (MCS), to deal with
data sparsity in SELD. ACS and MDS focus on augmenting the limited training
data with expanding direction of arrival (DOA) representations such that the
acoustic models trained with the augmented data are robust to localization
variations of acoustic sources. Next, time-domain mixing (TDM) and
time-frequency masking (TFM) are also investigated to deal with overlapping
sound events and data diversity. Finally, ACS, MCS, TDM and TFM are combined in
a step-by-step manner to form an effective four-stage data augmentation scheme.
Tested on the Detection and Classification of Acoustic Scenes and Events
(DCASE) 2020 data sets, our proposed augmentation approach greatly improves the
system performance, ranking our submitted system in the first place in the SELD
task of DCASE 2020 Challenge. Furthermore, we employ a ResNet-Conformer
architecture to model both global and local context dependencies of an audio
sequence to yield further gains over those architectures used in the DCASE 2020
SELD evaluations.Comment: 12 pages, 8 figure
Short-term glutamine supplementation decreases lung inflammation and the receptor for advanced glycation end-products expression in direct acute lung injury in mice
BACKGROUND: Glutamine (GLN) has been reported to improve clinical and experimental sepsis outcomes. However, the mechanisms underlying the actions of GLN remain unclear, and may depend upon the route of GLN administration and the model of acute lung injury (ALI) used. The aim of this study was to investigate whether short-term GLN supplementation had an ameliorative effect on the inflammation induced by direct acid and lipopolysaccharide (LPS) challenge in mice. METHODS: Female BALB/c mice were divided into two groups, a control group and a GLN group (4.17% GLN supplementation). After a 10-day feeding period, ALI was induced by intratracheal administration of hydrochloric acid (pH 1.0; 2 mL/kg of body weight [BW]) and LPS (5 mg/kg BW). Mice were sacrificed 3 h after ALI challenge. In this early phase of ALI, serum, lungs, and bronchoalveolar lavage fluid (BALF) from the mice were collected for further analysis. RESULTS: The results of this study showed that ALI-challenged mice had a significant increase in myeloperoxidase activity and expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α in the lung compared with unchallenged mice. Compared with the control group, GLN pretreatment in ALI-challenged mice reduced the levels of receptor for advanced glycation end-products (RAGE) and IL-1β production in BALF, with a corresponding decrease in their mRNA expression. The GLN group also had markedly lower in mRNA expression of cyclooxygenase-2 and NADPH oxidase-1. CONCLUSIONS: These results suggest that the benefit of dietary GLN may be partly contributed to an inhibitory effect on RAGE expression and pro-inflammatory cytokines production at an early stage in direct acid and LPS-induced ALI in mice
A bifurcation-type result for Kirchhoff equations
This paper deals with a class of Kirchhoff type elliptic Dirichlet boundary value problems where the combined effects of Kirchhoff term and nonlinear term allow us to establish a bifurcation-type result as the positive parameter varies
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