122 research outputs found

    Looking Beyond Label Noise: Shifted Label Distribution Matters in Distantly Supervised Relation Extraction

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    In recent years there is a surge of interest in applying distant supervision (DS) to automatically generate training data for relation extraction (RE). In this paper, we study the problem what limits the performance of DS-trained neural models, conduct thorough analyses, and identify a factor that can influence the performance greatly, shifted label distribution. Specifically, we found this problem commonly exists in real-world DS datasets, and without special handing, typical DS-RE models cannot automatically adapt to this shift, thus achieving deteriorated performance. To further validate our intuition, we develop a simple yet effective adaptation method for DS-trained models, bias adjustment, which updates models learned over the source domain (i.e., DS training set) with a label distribution estimated on the target domain (i.e., test set). Experiments demonstrate that bias adjustment achieves consistent performance gains on DS-trained models, especially on neural models, with an up to 23% relative F1 improvement, which verifies our assumptions. Our code and data can be found at \url{https://github.com/INK-USC/shifted-label-distribution}.Comment: 13 pages: 10 pages paper, 3 pages appendix. Appears at EMNLP 201

    Hybrid density functionals with proper exact exchange

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    Hybrid density functionals have the best overall performance among standard density func-tional approximations (DFA). According to their original design, hybrid DFAs are supposedto use the exact exchange (EXX). However, when hybrid functionals were originally intro-duced, there was no simple method to compute EXX, so all of their practical implementationsstarted using the Hartree–Fock exchange (HFX), which can be computed easily and is simi-lar to but distinct from EXX. Recent development of an efficient method for computing EXXmade it possible to implement hybrid functionals in line with their original definition. Weimplemented EXX in the PBE0 functional and compared its performance with that of HFX.We found that using EXX in PBE0 improves the standard enthalpies of formation, and thisimprovement increases with the size of the basis set and the size of the system. The max-imum improvement in standard enthalpies of formation of the G3-3 test set is 0.4 kcal/molwhen using 6-311++G(3df,3pd) basis set. For a hybrid density functional, the difference in theground-state energies computed using EXX and HFX depends quadratically on the percentageof EXX in the functional. We have also developed a method to generate the exact remainderexchange-correlation potential of the generalized Kohn–Sham DFT

    DUNE: Improving Accuracy for Sketch-INT Network Measurement Systems

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    In-band Network Telemetry (INT) and sketching algorithms are two promising directions for measuring network traffics in real time. To combine sketch with INT and preserve their advantages, a representative approach is to use INT to send a switch sketch in small pieces (called sketchlets) to end-host for reconstructing an identical sketch. However, in this paper, we reveal that when naively selecting buckets to sketchlets, the end-host reconstructed sketch is inaccurate. To overcome this problem, we present DUNE, an innovative sketch-INT network measurement system. DUNE incorporates two key innovations: First, we design a novel scatter sketchlet that is more efficient in transferring measurement data by allowing a switch to select individual buckets to add to sketchlets; Second, we propose lightweight data structures for tracing "freshness" of the sketch buckets, and present algorithms for smartly selecting buckets that contain valuable measurement data to send to end-host. We theoretically prove the effectiveness of our proposed methods, and implement a prototype on commodity programmable switch. The results of extensive experiments driven by real-world traffics on DUNE suggest that our proposed system can substantially improve the measurement accuracy at a trivial cost.Comment: Technical report for the paper published in IEEE INFOCOM 202

    Stackelberg game-based optimal electricity trading method for distribution networks with small-micro industrial parks

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    In order to improve the operating benefits of the distribution network (DN) and reduce the energy consumption costs of small-micro industrial parks (SMIPs), a two-layer optimal electricity trading method for DN with SMIPs is proposed. First, based on the Stackelberg game, a multi-objective two-layer optimal trading model for DN and SMIP is established. In the upper layer, the DN agent is regarded as the leader, and a trading model is established with the goal of maximizing the profits of agents. In the lower layer, an energy optimization model is proposed for the SMIP operators, which are regarded as the followers, with the goal of minimizing the operating costs. According to the buying and selling electricity prices at the upper and lower layers, a dynamic pricing strategy is formulated. The Karush–Kuhn–Tucker condition (KKT) is introduced to transform the two-layer model into a single-layer model, and based on linear transformations, the model is further converted into a mixed-integer linear programming model. The transformations aim to address the non-linear issues arising from multivariable coupling between the upper and lower-layer trading models. The simulation results show that the trading strategy proposed in this paper can effectively increase the profit of DNs while reducing the operating costs of SMIPs and can provide a reference for decision-making in the electricity market (EM) with the participation of SMIP

    Effect of three oral pathogens on the TMA-TMAO metabolic pathway

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    BackgroundTrimethylamine-N-oxide (TMAO) is produced by hepatic flavin-containing monooxygenase 3 (FMO3) from trimethylamine (TMA). High TMAO level is a biomarker of cardiovascular diseases and metabolic disorders, and it also affects periodontitis through interactions with the gastrointestinal microbiome. While recent findings indicate that periodontitis may alter systemic TMAO levels, the specific mechanisms linking these changes and particular oral pathogens require further clarification.MethodsIn this study, we established a C57BL/6J male mouse model by orally administering Porphyromonas gingivalis (P. gingivalis, Pg), Fusobacterium nucleatum (F. nucleatum, Fn), Streptococcus mutans (S. mutans, Sm) and PBS was used as a control. We conducted LC-MS/MS analysis to quantify the concentrations of TMAO and its precursors in the plasma and cecal contents of mice. The diversity and composition of the gut microbiome were analyzed using 16S rRNA sequencing. TMAO-related lipid metabolism and enzymes in the intestines and liver were assessed by qPCR and ELISA methods. We further explored the effect of Pg on FMO3 expression and lipid molecules in HepG2 cells by stimulating the cells with Pg-LPS in vitro.ResultsThe three oral pathogenic bacteria were orally administered to the mice for 5 weeks. The Pg group showed a marked increase in plasma TMAO, betaine, and creatinine levels, whereas no significant differences were observed in the gut TMAO level among the four groups. Further analysis showed similar diversity and composition in the gut microbiomes of both the Pg and Fn groups, which were different from the Sm and control groups. The profiles of TMA-TMAO pathway-related genera and gut enzymes were not significantly different among all groups. The Pg group showed significantly higher liver FMO3 levels and elevated lipid factors (IL-6, TG, TC, and NEFA) in contrast to the other groups. In vitro experiments confirmed that stimulation of HepG2 cells with Pg-LPS upregulated the expression of FMO3 and increased the lipid factors TC, TG, and IL-6.ConclusionThis study conclusively demonstrates that Pg, compared to Fn and Sm, plays a critical role in elevating plasma TMAO levels and significantly influences the TMA-TMAO pathway, primarily by modulating the expression of hepatic FMO3 and directly impacting hepatic lipid metabolism

    Altered Brain Signal Variability in Patients With Generalized Anxiety Disorder

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    Generalized anxiety disorder (GAD) is characterized by a chronic, continuous symptom of worry and exaggerated startle response. Although functional abnormality in GAD has been widely studied using functional magnetic resonance imaging (fMRI), the dynamic signatures of GAD are not fully understood. As a vital index of brain function, brain signal variability (BSV) reflects the capacity of state transition of neural activities. In this study, we recruited 47 patients with GAD and 38 healthy controls (HCs) to investigate whether or not BSV is altered in patients with GAD by measuring the standard deviation of fMRI signal of each voxel. We found that patients with GAD exhibited decreased BSV in widespread regions including the visual network, sensorimotor network, frontoparietal network, limbic system, and thalamus, indicating an inflexible brain state transfer pattern in these systems. Furthermore, the correlation between BSV and trait anxiety score was prone to be positive in patients with GAD but negative in HCs. The opposite relationships between BSV and anxiety level in the two groups indicate that the brain with moderate anxiety level may stay in the most stable rather than in the flexible state. As the first study of BSV in GAD, we revealed extensively decreased BSV in patients with GAD similar to that in other mental disorders but with a non-linear relationship between BSV and anxiety level indicating a novel neurodynamic mechanism of the anxious brain

    Microstructure and mechanical properties of NiAl-Cr(Mo)-Hf/Ho near-eutectic alloy prepared by suction casting

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    The microstructure and mechanical properties of 0.15 at.% Hf and 0.2 at.% Ho doped Ni-33Al-28Cr-6Mo near-eutectic alloys prepared by conventional casting and suction casting were investigated. The results reveal that the addition of Hf and Ho results in the formation of Ni(2)AlHf and Ni(2)Al(3)Ho phases, respectively, along the NiAl and Cr(Mo) phase interface in intercellular regions. Compared with the conventional-cast alloy, the microstructure of suction-cast alloy is well optimized, characterized by the thin interlamellar spacing, high proportion of eutectic cell area and fine homogeneously distributed Ni(2)AlHf and Ni(2)Al(3)Ho phases. Furthermore, the room temperature mechanical properties of the suction-cast alloy improve significantly, which can be attributed to fine microstructure, uniform distribution of the Ni(2)AlHf and Ni(2)Al(3)Ho phases and solid solubility extension
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