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4. Black Box Lie Group Preconditioners for SGD

Author

Li, Xilin

Subjects
Statistics - Machine Learning, Computer Science - Machine Learning
Abstract

A matrix free and a low rank approximation preconditioner are proposed to accelerate the convergence of stochastic gradient descent (SGD) by exploiting curvature information sampled from Hessian-vector products or finite differences of parameters and gradients similar to the BFGS algorithm. Both preconditioners are fitted with an online updating manner minimizing a criterion that is free of line search and robust to stochastic gradient noise, and further constrained to be on certain connected Lie groups to preserve their corresponding symmetry or invariance, e.g., orientation of coordinates by the connected general linear group with positive determinants. The Lie group's equivariance property facilitates preconditioner fitting, and its invariance property saves any need of damping, which is common in second-order optimizers, but difficult to tune. The learning rate for parameter updating and step size for preconditioner fitting are naturally normalized, and their default values work well in most situations., Comment: HOOML 2022

Published
2022

5. Dictionary-Based Fusion of Contact and Acoustic Microphones for Wind Noise Reduction

Author

Tammen, Marvin, Li, Xilin, Doclo, Simon, and Theverapperuma, Lalin

Subjects
Electrical Engineering and Systems Science - Audio and Speech Processing, Computer Science - Sound
Abstract

In mobile speech communication applications, wind noise can lead to a severe reduction of speech quality and intelligibility. Since the performance of speech enhancement algorithms using acoustic microphones tends to substantially degrade in extremely challenging scenarios, auxiliary sensors such as contact microphones can be used. Although contact microphones offer a much lower recorded wind noise level, they come at the cost of speech distortion and additional noise components. Aiming at exploiting the advantages of acoustic and contact microphones for wind noise reduction, in this paper we propose to extend conventional single-microphone dictionary-based speech enhancement approaches by simultaneously modeling the acoustic and contact microphone signals. We propose to train a single speech dictionary and two noise dictionaries and use a relative transfer function to model the relationship between the speech components at the microphones. Simulation results show that the proposed approach yields improvements in both speech quality and intelligibility compared to several baseline approaches, most notably approaches using only the contact microphones or only the acoustic microphone., Comment: accepted at IWAENC 22

Published
2022
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6. Optimizing the detection of N-nitrosamine mutagenicity in the Ames test

Author

Heflich, Robert H., Bishop, Michelle E., Mittelstaedt, Roberta A., Yan, Jian, Guerrero, Sharon K., Sims, Audrey M., Mitchell, Kamela, Moore, Nyosha, Li, Xilin, Mei, Nan, Elespuru, Rosalie K., King, Sruthi T., Keire, David A., Kruhlak, Naomi L., Dorsam, Robert T., Raw, Andre S., Davis Bruno, Karen L., McGovern, Timothy J., and Atrakchi, Aisar H.

Published
2024
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14. Repeat treatment of organotypic airway cultures with ethyl methanesulfonate causes accumulation of somatic cell mutations without expansion of bronchial-carcinoma-specific cancer driver mutations

Author

Wang, Yiying, Le, Yuan, Harris, Kelly L., Chen, Ying, Li, Xilin, Faske, Jennifer, Wynne, Rebecca A., Mittelstaedt, Roberta A., Cao, Xuefei, Miranda-Colon, Jaime, Elkins, Lana, Muskhelishvili, Levan, Davis, Kelly, Mei, Nan, Sun, Wei, Robison, Timothy W., Heflich, Robert H., and Parsons, Barbara L.

Published
2024
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27. Cell-surface anchoring of Listeria adhesion protein on L. monocytogenes is fastened by internalin B for pathogenesis

Author

Liu, Dongqi, Bai, Xingjian, Helmick, Harrison D.B., Samaddar, Manalee, Amalaradjou, Mary Anne Roshni, Li, Xilin, Tenguria, Shivendra, Gallina, Nicholas L.F., Xu, Luping, Drolia, Rishi, Aryal, Uma K., Moreira, Gustavo Marçal Schmidt Garcia, Hust, Michael, Seleem, Mohamed N., Kokini, Jozef L., Ostafe, Raluca, Cox, Abigail, and Bhunia, Arun K.

Published
2023
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30. Hand-tremor frequency estimation in videos

Author

Pintea, Silvia L., Zheng, Jian, Li, Xilin, Bank, Paulina J. M., van Hilten, Jacobus J., and van Gemert, Jan C.

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

We focus on the problem of estimating human hand-tremor frequency from input RGB video data. Estimating tremors from video is important for non-invasive monitoring, analyzing and diagnosing patients suffering from motor-disorders such as Parkinson's disease. We consider two approaches for hand-tremor frequency estimation: (a) a Lagrangian approach where we detect the hand at every frame in the video, and estimate the tremor frequency along the trajectory; and (b) an Eulerian approach where we first localize the hand, we subsequently remove the large motion along the movement trajectory of the hand, and we use the video information over time encoded as intensity values or phase information to estimate the tremor frequency. We estimate hand tremors on a new human tremor dataset, TIM-Tremor, containing static tasks as well as a multitude of more dynamic tasks, involving larger motion of the hands. The dataset has 55 tremor patient recordings together with: associated ground truth accelerometer data from the most affected hand, RGB video data, and aligned depth data., Comment: Best paper at ECCV-2018 Workshop on Observing and Understanding Hands in Action

Published
2018

34. Study on the structure characterization and swelling properties of the Fe3O4/CMS composite membrane.

Author

Liu, Xiaokai, Zhou, Lijuan, Li, Xilin, Zhao, Baiyun, He, Hao, Zhao, Xuan, Wang, Chenxu, and Wang, Li

Subjects
COMPOSITE membranes (Chemistry), FICK'S laws of diffusion, IONIC strength, X-ray diffraction, THERMAL stability
Abstract

In order to improve the functionality of cellulosic materials research and development of high performance soluble materials. Therefore, the Fe3O4/CMS composite membrane was prepared by using carboxymethyl salix powder (CMS) and Fe3O4 as raw materials, 1-propenyl-3-methylimidazolium chloride and dimethyl sulfoxide as dissolution system. The effects of swelling time, swelling temperature, pH and ionic strength on the swelling performance of Fe3O4/CMS composite membranes and the swelling kinetics of the composite membranes were studied. The structure of the composite membrane was characterized by SEM, FT-IR, XRD and TG. The results showed that the swelling degree reached 5.54 g·g−1, when the swelling time was 45 min, the swelling temperature was 65°C, the pH was 5 and the ionic strength was 0.08 mol·L−1. The initial phase of dissolution of the composite membrane fits well with the Fickian diffusion model, and the whole dissolution process belongs to the Schott model, indicating that the main role of the dissolution process is the diffusion of water molecules, while the composite membrane can be preserved for a long time at high temperature, which provides sustainability for the composite membrane. The characterization results showed that the surface of Fe3O4/CMS composite film was rough with small grooves. The O-H effect was enhanced and the Fe-O absorption peak appeared at 600 cm−1, indicating that Fe3O4 had been successfully loaded onto the cellulose membrane. The Fe3O4/CMS composite membrane belonged to cellulose type II structure, meanwhile, the composite membrane had good thermal stability. [ABSTRACT FROM AUTHOR]

Published
2024
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35. An ultralight all‐fiber‐structure sponge with thermal and electromagnetic integrated insulation property.

Author

Su, Liang, Lu, Jiaxiang, Zhang, Huan, Li, Xilin, Wang, Jinbo, Wang, Haolun, and Lin, Sen

Subjects
HEAT convection, THERMAL insulation, SPONGE (Material), EXTREME environments, ELECTROMAGNETIC interference, HEAT radiation & absorption, YTTRIA stabilized zirconium oxide
Abstract

The integration of thermal and electromagnetic interference (EMI) insulation is of great significance for fields such as aerospace that face extreme environments. The challenge lies in ensuring that the protective layer is lightweight while simultaneously possessing the ability to suppress heat conduction, heat convection, thermal radiation, and electromagnetic radiation. To address these challenges, we propose a novel ultralight all‐fiber‐structure composite sponge, yttria‐stabilized zirconia/polyvinyl butyral‐supported silver (YAP) nanofiber sponge, with ultralight mass (∼65 mg/cm3), exceptionally low thermal conductivity (21 mW/m K at 25°C, and 329 mW/m K at 500°C), and remarkable EMI shielding effectiveness (∼62.6 dB). Moreover, benefiting from its all‐fiber‐structure, the YAP nanofiber sponge can endure 100 cycles of compression up to 50% of its original volume while retaining its mechanical properties with minimal degradation. These characteristics render YAP nanofiber sponge an ideal material for integrated thermal and EMI insulation, offering a promising solution to the rigorous demands of extreme environment protection such as space exploration. [ABSTRACT FROM AUTHOR]

Published
2024
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40. Modal decomposition of instabilities and its applications in analysis and design of cold-formed steel structures

Author

Li, Xilin, becque, jurgen, and davison, buick

Subjects
624.1
Abstract

The construction industry has witnessed a widespread of cold-formed steel structures (CFS) in the recent years. However, despite its advantages due to the thin-walled nature of such kind of structures they are highly susceptible to instabilities including coupled instabilities. Currently the modal decomposition method used to analyse these coupled instabilities still has space of improvement. For example, the method generates overly rigid distortional and global modes, and an increased computational effort is needed when dealing with complex cross-sections. Regarding the design of CFS, the existing design code is cumbersome to implement since different empiral formulas are proposed for different types of buckling. In addition, an overly conservative prediction of the ultimate load is obtained for sections where there is significant disparity between the slenderness values of different parts. The aim of the project is to improve the modal decomposition methods and to exploit its application aspects in the analysis and design of CFS undergoing coupled instabilities. First, two new modal decomposition methods are developed, namely the polarisation method and the nodal force method. Both of the methods are based on the finite strip method (FSM), and are aimed at overcoming the disadvantages of the existing method. Second, the nodal force method is applied to analyse the deformed shape of CFS columns in the post-buckling stage, in which the contributions of buckling modes are traced until the column fails. This lays a foundation for the development of design approaches dealing with coupled instabilities. In addition, the modal decomposition method is applied to the statistical analysis of geometric imperfections of CFS specimens, which leads to a scientific charactorisation of geometric imperfections. Finally, a design approach is developed based on the concept of the direct strength method (DSM). In the proposed design approach, the initial post-buckling stiffness is considered as an input parameter in addition to the critical load. These input parameters are then used to establish a multi-linear model approximating the elastic post-buckling behaviour, which is linked to the ultimate load using empirical formulas. In the proposed design approach, two improvements are made. First, a unified design formula is used for different types of buckling, which are distinguished by the difference in post-buckling stiffness. Second, the overly conservative prediction of the ultimate load, when one part of the section is significantly slender, is avoided. This is due to the fact that in these cases, the reduction of the stiffness when buckling occurs is comparably minor.

Published
2017

43. An Online Power Angle Remote Estimation Method for GFL-GFM-Converters Paralleled System

Author

Tian, Zhen, Feng, Pan, Li, Xilin, Huang, Meng, Bahrani, Behrooz, Zha, Xiaoming, and Shao, Chong

Abstract

Complicated dynamic interactions in multi-grid-connected converter (GCC) systems have unexpected impacts on the overall response of the system. Online state sharing among different GCCs can enhance the coordination of the whole system. However, due to the significant communication delay, the power angle and frequency states cannot be transmitted rapidly enough. In this letter, an innovative power angle remote estimation method is proposed to realize real-time power angle and frequency information sharing among different GCCs with the local measurement of voltage and power. This method decouples interactive information by revealing the transient response mechanism of the network. The proposed method could inspire distributed cooperative control and online transient stability analysis for multi-GCC systems.

Published
2024
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44. Macleaya cordataextract exhibits some potential as a surrogate antibiotic by improving gastrointestinal epithelial status and humoral response in goats

Author

Yan, Qiongxian, Li, Xilin, Zhou, Xiaoling, Chen, Wenxun, Tian, Xingzhou, Wittayakun, Suntorn, Paengkoum, Pramote, and Tan, Zhiliang

Abstract

Macleaya cordataextract (MCE) is a potential replacement for antibiotics. In the current study, effects of MCE on the gastrointestinal health and humoral responses of host animals were explored. A total of 30 weanling goats with similar body weight of 9.15 ± 1.36 kg were randomly allocated into three groups (n = 10 per group): control group (CON group, fed with a basal diet), antibiotic group (Abx group, fed with the basal diet supplemented with 0.18 g/d vancomycin and 0.36 g/d neomycin), and MCE group (fed with the basal diet supplemented with 5 g/d MCE), for three weeks. Results showed that antibiotic addition decreased the height and area of rumen papillae, ruminal mucosa Toll-like receptor 8 (TLR8), interleukin-8 (IL-8) and interleukin-1β(IL-1β) gene relative expression levels and microbial diversity, altered the volatile fatty acid (VFA) profile in the rumen, and increased monocytes amount and CD4+T cells percentage in the peripheral blood (P < 0.05) compared to CON group. MCE addition increased the average daily gain, ileal villus height, villus height/crypt depth, and immunoglobulin M (IgM) content in the peripheral blood (P < 0.05) compared to the CON. Additionally, MCE addition decreased the proportion of isobutyric acid in the chyme of the ileum (P = 0.005) compared to the CON group. These results suggest that antibiotic supplementation may suppress the epithelial state and microbial diversity and fermentation in goats, but stimulate cellular response to maintain the growth performance of goats. MCE administration improved the epithelial state and humoral response to promote the growth performance in goats.

Published
2024
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46. Toxins in Botanical Drugs and Plant-derived Food and Feed – from Science to Regulation: A Workshop Review

Author

Schrenk, Dieter, Allemang, Ashley, Fahrer, Jörg, Harms, Henrik, Li, Xilin, Lin, Ge, Mahony, Catherine, Mulder, Patrick, Peijnenburg, Ad, Pfuhler, Stefan, Punt, Ans, Sievers, Hartwig, Troutman, John, Widjaja, Frances, Schrenk, Dieter, Allemang, Ashley, Fahrer, Jörg, Harms, Henrik, Li, Xilin, Lin, Ge, Mahony, Catherine, Mulder, Patrick, Peijnenburg, Ad, Pfuhler, Stefan, Punt, Ans, Sievers, Hartwig, Troutman, John, and Widjaja, Frances

Abstract

In September 2022, the 3rd International Workshop on pyrrolizidine alkaloids (PAs) and related phytotoxins was held on-line, entitled ʼToxins in botanical drugs and plant-derived food and feed – from science to regulationʼ. The workshop focused on new findings about the occurrence, exposure, toxicity, and risk assessment of PAs. In addition, new scientific results related to the risk assessment of alkenylbenzenes, a distinct class of herbal constituents, were presented. The presence of PAs and alkenylbenzenes in plant-derived food, feed, and herbal medicines has raised health concerns with respect to their acute and chronic toxicity but mainly related to the genotoxic and carcinogenic properties of several congeners. The compounds are natural constituents of a variety of plant families and species widely used in medicinal, food, and feed products. Their individual occurrence, levels, and toxic properties, together with the broad range of congeners present in nature, represent a striking challenge to modern toxicology. This review tries to provide an overview of the current knowledge on these compounds and indicates needs and perspectives for future research.

Published
2024

47. "It Could Be Better" Can Make It Worse: When and Why People Mistakenly Communicate Upward Counterfactual Information.

Author

Li, Xilin, Hsee, Christopher K., and O'Brien, Ed

Subjects
COUNTERFACTUALS (Logic), EGOISM, FIRST impression (Psychology), IMPRESSION formation (Psychology), CONSUMER behavior, MARKETING, MARKETING research
Abstract

Imagine you are a real estate agent and are showing a prospective buyer a house with a lake view, but it is foggy, and the view is less than ideal. Are you inclined to tell the prospective buyer, "Unfortunately, it is foggy outside. If it were not foggy, the view would be even better!"? Eight studies, spanning diverse domains, reveal a novel discrepancy: most presenters (e.g., the seller) choose to communicate such upward counterfactual information (UCI) to experiencers (e.g., the prospective buyer), believing it will enhance experiencers' impressions (e.g., of the house)—yet UCI actually worsens their impressions. This discrepancy arises because presenters insufficiently account for the fact that they possess more knowledge about the presented target than experiencers do; they fail to realize that noting an imperfection reveals it. Accordingly, when experiencers are knowledgeable about the target, either because the imperfection is obvious or because they can easily envision the upward counterfactual, the discrepancy attenuates. Finally, the presenter–experiencer discrepancy occurs only when the counterfactual information is upward, such that presenters do not overcommunicate downward counterfactual information, which rules out a desire to share any information as an alternative mechanism for presenters' communication decisions. Together, this research highlights the prevalence and costs of sharing UCI. [ABSTRACT FROM AUTHOR]

Published
2023
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48. Hand-Tremor Frequency Estimation in Videos

Author

Pintea, Silvia L., Zheng, Jian, Li, Xilin, Bank, Paulina J. M., van Hilten, Jacobus J., van Gemert, Jan C., Hutchison, David, Series Editor, Kanade, Takeo, Series Editor, Kittler, Josef, Series Editor, Kleinberg, Jon M., Series Editor, Mattern, Friedemann, Series Editor, Mitchell, John C., Series Editor, Naor, Moni, Series Editor, Pandu Rangan, C., Series Editor, Steffen, Bernhard, Series Editor, Terzopoulos, Demetri, Series Editor, Tygar, Doug, Series Editor, Leal-Taixé, Laura, editor, and Roth, Stefan, editor

Published
2019
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