187 research outputs found
Towards Trustworthy Dataset Distillation
Efficiency and trustworthiness are two eternal pursuits when applying deep
learning in real-world applications. With regard to efficiency, dataset
distillation (DD) endeavors to reduce training costs by distilling the large
dataset into a tiny synthetic dataset. However, existing methods merely
concentrate on in-distribution (InD) classification in a closed-world setting,
disregarding out-of-distribution (OOD) samples. On the other hand, OOD
detection aims to enhance models' trustworthiness, which is always
inefficiently achieved in full-data settings. For the first time, we
simultaneously consider both issues and propose a novel paradigm called
Trustworthy Dataset Distillation (TrustDD). By distilling both InD samples and
outliers, the condensed datasets are capable to train models competent in both
InD classification and OOD detection. To alleviate the requirement of real
outlier data and make OOD detection more practical, we further propose to
corrupt InD samples to generate pseudo-outliers and introduce Pseudo-Outlier
Exposure (POE). Comprehensive experiments on various settings demonstrate the
effectiveness of TrustDD, and the proposed POE surpasses state-of-the-art
method Outlier Exposure (OE). Compared with the preceding DD, TrustDD is more
trustworthy and applicable to real open-world scenarios. Our code will be
publicly available.Comment: 20 pages, 20 figure
Wide-Area Damping Controller of FACTS Devices for Inter-Area Oscillations Considering Communication Time Delays
The usage of remote signals obtained from a wide-area measurement system (WAMS) introduces time delays to a wide-area damping controller (WADC), which would degrade system damping and even cause system instability. The time-delay margin is defined as the maximum time delay under which a closed-loop system can remain stable. In this paper, the delay margin is introduced as an additional performance index for the synthesis of classical WADCs for flexible ac transmission systems (FACTS) devices to damp inter-area oscillations. The proposed approach includes three parts: a geometric measure approach for selecting feedback remote signals, a residue method for designing phase-compensation parameters, and a Lyapunov stability criterion and linear matrix inequalities (LMI) for calculating the delay margin and determining the gain of the WADC based on a tradeoff between damping performance and delay margin. Three case studies are undertaken based on a four-machine two-area power system for demonstrating the design principle of the proposed approach, a New England ten-machine 39-bus power system and a 16-machine 68-bus power system for verifying the feasibility on larger and more complex power systems. The simulation results verify the effectiveness of the proposed approach on providing a balance between the delay margin and the damping performance
Adaptive power oscillation damping controller of superconducting magnetic energy storage device for interarea oscillations in power system
Impedance Modeling and Stability Analysis of Grid-Connected DFIG-based Wind Farm with a VSC-HVDC
microRNA-33a-5p increases radiosensitivity by inhibiting glycolysis in melanoma.
Glycolysis was reported to have a positive correlation with radioresistance. Our previous study found that the miR-33a functioned as a tumor suppressor in malignant melanoma by targeting hypoxia-inducible factor1-alpha (HIF-1α), a gene known to promote glycolysis. However, the role of miR-33a-5p in radiosensitivity remains to be elucidated. We found that miR-33a-5p was downregulated in melanoma tissues and cells. Cell proliferation was downregulated after overexpression of miR-33a-5p in WM451 cells, accompanied by a decreased level of glycolysis. In contrast, cell proliferation was upregulated after inhibition of miR-33a-5p in WM35 cells, accompanied by increased glycolysis. Overexpression of miR-33a-5p enhanced the sensitivity of melanoma cells to X-radiation by MTT assay, while downregulation of miR-33a-5p had the opposite effects. Finally, in vivo experiments with xenografts in nude mice confirmed that high expression of miR-33a-5p in tumor cells increased radiosensitivity via inhibiting glycolysis. In conclusions, miR-33a-5p promotes radiosensitivity by negatively regulating glycolysis in melanoma
H.pylori Infection inhibits Inflammatory Bowel Disease(IBD) by affecting the intestinal flora: A systematic Review
Background: Inflammatory bowel diseases (IBD) are chronic, relapsing-remitting diseases of the gastrointestinal tract, including Crohn’s disease (CD), Ulcerative Colitis (UC), and Unclassified IBD (IBDU). Their pathogenesis involves genes and the environment as cofactors in inducing autoimmunity; mainly, the interactions between enteric pathogens and immunity are studied. For example, Helicobacter pylori (HP) is a common pathogen causing gastric inflammation. However, studies found that the number of people with HP was lower than those with IBD. Therefore, it suggests that HP might protect against IBD. Methods: The search terms "helicobacter pylori," "inflammatory bowel disease," "Crohn's disease," and "ulcerative colitis" were entered into the PubMed database. Embase, Medline, Web of Science, Scopus, PubMed publisher, Cochrane, and Google Scholar were also searched. The HP prevalence rates in IBD patients, CD patients, UC patients, and IBDU patients were calculated. So its to prove that there is an inverse relationship between HP and IBD, each group was compared to a control group. Results: Even when the comparison was made separately between each group of newly diagnosed patients and controls to rule out the possibility of pharmacologic bias, the data showed an inverse relationship between the IBD group and the controls. Conclusion: The results of this review demonstrate a striking inverse association between HP infection and the prevalence of inflammatory bowel disease (IBD), regardless of the type of IBD considered across different geographic regions. Anyway, data should be interpreted with care because more research is needed on this topic that is broader, more prospective, and more consistent. This could lead to new ideas about how the environment could cause IBD. Keywords: Inflammatory bowel disease; Helicobacter pylori; Crohn’s disease; Ulcerative colitis; Colorectal cancer DOI: 10.7176/JMPB/72-04 Publication date: May 31st 202
Impact of Power Grid Strength and PLL Parameters on Stability of Grid-Connected DFIG Wind Farm
This paper investigates the impact of power grid strength and phase-locked loop (PLL) parameters on small signal stability of grid-connected doubly fed induction generator (DFIG)-based wind farm. Modal analysis of the grid-connected DFIG wind turbine under different operating conditions and various power grid strengths are investigated at first. Modal analysis results reveal that the DFIG connected to a weak grid may easily lose stability under the heavy-duty operating conditions due to PLL oscillation. The object of this paper is to identify the PLL oscillation mechanism as well as influence factors and propose a damping solution for this oscillation mode. A simplified linear system model of the grid-connected DFIG wind turbine is proposed for analyzing the PLL oscillation. Through the complex torque coefficients method and using this model, the oscillation mechanism and influence factors including the power grid strength and the PLL parameters are identified. To suppress this PLL oscillation, a mixed H2/H∞ robust damping controller is proposed and designed for the DFIG. Electromagnetic transient simulation results of both single-DFIG system and multiply-DFIG system verify the correctness of the analysis results and effectiveness of the proposed damping controller
Experimental observation of topological Fermi arcs in type-II Weyl semimetal MoTe2
Weyl semimetal is a new quantum state of matter [1-12] hosting the condensed
matter physics counterpart of relativisticWeyl fermion [13] originally
introduced in high energy physics. The Weyl semimetal realized in the TaAs
class features multiple Fermi arcs arising from topological surface states [10,
11, 14-16] and exhibits novel quantum phenomena, e.g., chiral anomaly induced
negative mag-netoresistance [17-19] and possibly emergent supersymmetry [20].
Recently it was proposed theoretically that a new type (type-II) of Weyl
fermion [21], which does not have counterpart in high energy physics due to the
breaking of Lorentz invariance, can emerge as topologically-protected touching
between electron and hole pockets. Here, we report direct spectroscopic
evidence of topological Fermi arcs in the predicted type-II Weyl semimetal
MoTe2 [22-24]. The topological surface states are confirmed by directly
observing the surface states using bulk-and surface-sensitive angle-resolved
photoemission spectroscopy (ARPES), and the quasi-particle interference (QPI)
pattern between the two putative Fermi arcs in scanning tunneling microscopy
(STM). Our work establishes MoTe2 as the first experimental realization of
type-II Weyl semimetal, and opens up new opportunities for probing novel
phenomena such as exotic magneto-transport [21] in type-II Weyl semimetals.Comment: submitted on 01/29/2016. Nature Physics, in press. Spectroscopic
evidence of the Fermi arcs from two complementary surface sensitive probes -
ARPES and STS. A comparison of the calculated band structure for T_d and 1T'
phase to identify the topological Fermi arcs in the T_d phase is also
included in the supplementary informatio
- …