30 research outputs found
Towards a live homogeneous database of solar active regions based on SOHO/MDI and SDO/HMI synoptic magnetograms. I. Automatic detection and calibration
Recent studies indicate that a small number of rogue solar active regions
(ARs) may have a significant impact on the end-of-cycle polar field and the
long-term behavior of solar activity. The impact of individual ARs can be
qualified based on their magnetic field distribution. This motivates us to
build a live homogeneous AR database in a series of papers. As the first of the
series, we develop a method to automatically detect ARs from 1996 onwards based
on SOHO/MDI and SDO/HMI synoptic magnetograms. The method shows its advantages
in excluding decayed ARs and unipolar regions and being compatible with any
available synoptic magnetograms. The identified AR flux and area are calibrated
based on the co-temporal SDO/HMI and SOHO/MDI data. The homogeneity and
reliability of the database are further verified by comparing it with other
relevant databases. We find that ARs with weaker flux have a weaker cycle
dependence. Stronger ARs show the weaker cycle 24 compared with cycle 23.
Several basic parameters, namely, location, area, and flux of negative and
positive polarities of identified ARs are provided in the paper. This paves the
way for AR's new parameters quantifying the impact on the long-term behavior of
solar activity to be presented in the subsequent paper of the series. The
constantly updated database covering more than two full solar cycles will be
beneficial for the understanding and prediction of the solar cycle. The
database and the detection codes are accessible online.Comment: Accepted for publication in the Astrophysical Journal Supplement
Series. 14 pages, 8 figures, 3 table
The Sun's Magnetic Power Spectra Over Two Solar Cycles. I. Calibration Between SDO/HMI And SOHO/MDI Magnetograms
The Sun's magnetic field is strongly structured over a broad range of scales.
The magnetic spatial power spectral analysis provides a powerful tool to
understand the various scales of magnetic fields and their interaction with
plasma motion. We aim to investigate the power spectra using spherical harmonic
decomposition of high-resolution SOHO/MDI and SDO/HMI synoptic magnetograms
covering three consecutive solar cycle minima in a series of papers. As the
first of the series, we calibrate and analyze the power spectra based on
co-temporal SDO/HMI and SOHO/MDI data in this paper. For the first time, we
find that the calibration factor between SOHO/MDI and SDO/HMI varies with
the spatial scale of the magnetic field, where is the degree of a
spherical harmonics. The calibration factor satisfies . With the calibration function, most
contemporaneous SOHO/MDI and SDO/HMI magnetograms show consistent power spectra
from about 8 Mm to the global scales over about 3 orders of magnitudes.
Moreover, magnetic power spectra from SOHO/MDI and SDO/HMI maps show
peaks/knees at corresponding to the typical supergranular scale
(about 35 Mm) constrained from direct velocimetric measurements. This study
paves the way for investigating the solar-cycle dependence of supergranulation
and magnetic power spectra in subsequent studies.Comment: Accepted for publication in the Astrophysical Journal. 15 pages, 7
figures, 2 table
Improving Multi-turn Emotional Support Dialogue Generation with Lookahead Strategy Planning
Providing Emotional Support (ES) to soothe people in emotional distress is an
essential capability in social interactions. Most existing researches on
building ES conversation systems only considered single-turn interactions with
users, which was over-simplified. In comparison, multi-turn ES conversation
systems can provide ES more effectively, but face several new technical
challenges, including: (1) how to adopt appropriate support strategies to
achieve the long-term dialogue goal of comforting the user's emotion; (2) how
to dynamically model the user's state. In this paper, we propose a novel system
MultiESC to address these issues. For strategy planning, drawing inspiration
from the A* search algorithm, we propose lookahead heuristics to estimate the
future user feedback after using particular strategies, which helps to select
strategies that can lead to the best long-term effects. For user state
modeling, MultiESC focuses on capturing users' subtle emotional expressions and
understanding their emotion causes. Extensive experiments show that MultiESC
significantly outperforms competitive baselines in both dialogue generation and
strategy planning. Our codes are available at
https://github.com/lwgkzl/MultiESC.Comment: Accepted by the main conference of EMNLP 202
Acupuncture for chronic, stable angina pectoris and an investigation of the characteristics of acupoint specificity: study protocol for a multicenter randomized controlled trial
BACKGROUND: Chronic stable angina pectoris (CSAP) is a common cardiovascular condition that endangers a patient’s life quality and longevity. As demonstrated in several clinical trials, acupuncture is attested to be effective for CSAP. Current trials are not adequate enough to provide high-quality evidence for clinical decision making, as a result of inadequate methodology design and small sample size. Notably, stark controversy toward acupoint specificity also exists in the clinical acupuncture trials for CSAP. Therefore, we designed the present study as a randomized controlled trial primarily to investigate the effectiveness of acupuncture in addition to routine care among patients with CSAP. Meanwhile, we examined whether acupoint on the disease-affected meridian (DAM) is superior to either acupoint on the non-affected meridian (NAM) or non-acupoint (NA), to further investigate the meridian-based characteristics of acupoint specificity. METHODS/DESIGN: This study was a multicenter, assessor and statistician blinded, randomized controlled trial in China. In this study, 404 participants in sum will be randomly assigned to four groups through central randomization in a 1:1:1:1 ratio. The whole study period is 20 weeks including a 4-week baseline period, a 4-week treatment period and a 12-week follow-up. Participants in the DAM group receive acupuncture stimulation at acupoints on the disease-affected meridian, and three different control groups will undergo acupuncture stimulation at the NAM, the non-acupoint and no intervention respectively, in addition to basic treatment. Participants in the acupuncture groups will receive 12 sessions of acupuncture treatment over 4 weeks, while the wait-listed (WL) group would receive free acupuncture treatment after the completion of the study. The outcome measures in this trial include the frequency of angina attack during 4 weeks as the primary outcome and eight other secondary outcomes. DISCUSSION: This trial will provide new and relatively high-quality evidence in acupuncture treatment for CSAP. Moreover, this trial may further validate the meridian-based characteristics of acupoint specificity by comparing the strength of acupoints on the disease-affected meridian versus that of the non-affected meridian, to further inspire optimization of acupuncture therapy for CSAP. TRIAL REGISTRATION: Clinical Trials.gov NCT0168623
Research on electromagnetic scattering characteristics of flexible stealth material based on its 3D model
With the widespread adoption of flexible stealth materials (FSMs) in radar stealth application, understanding their electromagnetic scattering information has become increasingly crucial. However, acquiring the electromagnetic scattering properties of FSMs solely through measurement can be challenging. Hence, this study proposes an electromagnetic scattering model for FSMs based on random undulating units formed by sweeping two parabola functions. Specifically, the multi-layer fast multipole method (MLFMM) is applied to calculate the model’s monostatic RCS within 8–12 GHz, enabling a comprehensive analysis of FSM’s electromagnetic scattering characteristics (ESCs). We fabricate an FSM sample for experimental validation and conduct meticulous measurements alongside theoretical calculations. Impressively, the calculated results exhibit relatively good agreement with the measured data, signifying our model’s reliability. Furthermore, by leveraging the proposed model and the MLFMM, we delve into the influence of various electromagnetic parameters, the undulating angle, and the size of undulation units on the ESCs of FSM. Our numerical results demonstrate that the ESCs of FSM exhibit regular variations in response to the changes in these parameters. In addition, we meticulously examine the interaction between electromagnetic waves and the material, further enriching our understanding of the observed results. This research provides valuable references for ESC investigation of flexible stealth material and radar stealth experimental design
Enhanced Heuristic Drift Elimination with Adaptive Zero-Velocity Detection and Heading Correction Algorithms for Pedestrian Navigation
As pedestrian dead-reckoning (PDR), based on foot-mounted inertial sensors, suffers from accumulated error in velocity and heading, an improved heuristic drift elimination (iHDE) with a zero-velocity update (ZUPT) algorithm was proposed for simultaneously reducing the error in heading and velocity in complex paths, i.e., with pathways oriented at 45°, curved corridors, and wide areas. However, the iHDE algorithm does not consider the changes in pedestrian movement modes, and it can deteriorate when a pedestrian walks along a straight path without a pre-defined dominant direction. To solve these two problems, we propose enhanced heuristic drift elimination (eHDE) with an adaptive zero-velocity update (AZUPT) algorithm and novel heading correction algorithm. The relationships between the magnitude peaks of the y-axis angular rate and the detection thresholds were established only using the readings of the three-axis accelerometer and the three-axis gyroscopic, and a mechanism for constructing temporary dominant directions in real time was introduced. Real experiments were performed and the results showed that the proposed algorithm can improve the still-phase detection accuracy of a pedestrian at different movement motions and outperforms the iHDE algorithm in complex paths with many straight features
PC-PU: Patch Correlation and Point Correlation for Effective Point Cloud Upsampling
Point cloud upsampling is to densify a sparse point set acquired from 3D
sensors, providing a denser representation for the underlying surface. Existing
methods divide the input points into small patches and upsample each patch
separately, however, ignoring the global spatial consistency between patches.
In this paper, we present a novel method PC-PU, which explores
patch-to-patch and point-to-point correlations for more effective and robust
point cloud upsampling. Specifically, our network has two appealing designs:
(i) We take adjacent patches as supplementary inputs to compensate the loss
structure information within a single patch and introduce a Patch Correlation
Module to capture the difference and similarity between patches. (ii) After
augmenting each patch's geometry, we further introduce a Point Correlation
Module to reveal the relationship of points inside each patch to maintain the
local spatial consistency. Extensive experiments on both synthetic and real
scanned datasets demonstrate that our method surpasses previous upsampling
methods, particularly with the noisy inputs. The code and data are at
\url{https://github.com/chenlongwhu/PC2-PU.git}.Comment: Accepted to ACM MM 202
TLR4 Signaling in MPP+-Induced Activation of BV-2 Cells
Aims. This work was conducted to establish an in vitro Parkinson’s disease (PD) model by exposing BV-2 cells to 1-methyl-4-phenylpyridinium (MPP+) and exploring the roles of TLR2/TLR4/TLR9 in inflammatory responses to MPP+. Methods/Results. MTT assay showed that cell viability of BV-2 cells was 84.78 ± 0.86% and 81.18 ± 0.99% of the control after incubation with 0.1 mM MPP+ for 12 hours and 24 hours, respectively. Viability was not significantly different from the control group. With immunofluorescence technique, we found that MPP+ incubation at 0.1 mM for 12 hours was the best condition to activate BV-2 cells. In this condition, the levels of TNF-α, IL-1β, and iNOS protein were statistically increased compared to the control according to ELISA tests. Real time RT-PCR and western blot measurements showed that TLR4 was statistically increased after 0.1 mM MPP+ incubation for 12 hours. Furthermore, after siRNA interference of TLR4 mRNA, NF-κB activation and the levels of TNF-α, IL-1β, and iNOS were all statistically decreased in this cell model. Conclusion. MPP+ incubation at the concentration of 0.1 mM for 12 hours is the best condition to activate BV-2 cells for mimicking PD inflammation in BV-2 cells. TLR4 signalling plays a critical role in the activation of BV-2 cells and the induction of inflammation in this cell model