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5. The Relationship Between Proximity of Collegiate Recreation Facilities and Usage Levels.

Author

Boren, Shaun, Li, Qichen, and Cramp, Catherine

Subjects
TRAVEL time (Traffic engineering), HEALTH behavior, ENVIRONMENTAL health, ECOLOGICAL models, RECREATION, LOGISTIC regression analysis
Abstract

The purpose of this study was to further explore the relationship between travel time and frequency of visits to collegiate recreation facilities. After surveying all students using collegiate recreation facilities at a large public southeastern US university, the local address of the 559 respondents was converted into travel time to their preferred facility using their preferred transportation method. This travel time was compared with swipe data on visits to the facility over a semester. A multinomial logistic regression was conducted to analyze the relationship between collegiate recreation facility usage level and travel time. Results support past research and ecological models of health behaviors demonstrating that proximity of recreation facilities is positively associated with higher usage by college students. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Meta-Embeddings Based On Self-Attention

Author

Li, Qichen, Lin, Yuanqing, Zhou, Luofeng, and Li, Jian

Subjects
Computer Science - Computation and Language
Abstract

Creating meta-embeddings for better performance in language modelling has received attention lately, and methods based on concatenation or merely calculating the arithmetic mean of more than one separately trained embeddings to perform meta-embeddings have shown to be beneficial. In this paper, we devise a new meta-embedding model based on the self-attention mechanism, namely the Duo. With less than 0.4M parameters, the Duo mechanism achieves state-of-the-art accuracy in text classification tasks such as 20NG. Additionally, we propose a new meta-embedding sequece-to-sequence model for machine translation, which to the best of our knowledge, is the first machine translation model based on more than one word-embedding. Furthermore, it has turned out that our model outperform the Transformer not only in terms of achieving a better result, but also a faster convergence on recognized benchmarks, such as the WMT 2014 English-to-French translation task.

Published
2020

9. SUM: Suboptimal Unitary Multi-task Learning Framework for Spatiotemporal Data Prediction

Author

Li, Qichen, Pei, Jiaxin, Zhang, Jianding, and Han, Bo

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

The typical multi-task learning methods for spatio-temporal data prediction involve low-rank tensor computation. However, such a method have relatively weak performance when the task number is small, and we cannot integrate it into non-linear models. In this paper, we propose a two-step suboptimal unitary method (SUM) to combine a meta-learning strategy into multi-task models. In the first step, it searches for a global pattern by optimising the general parameters with gradient descents under constraints, which is a geological regularizer to enable model learning with less training data. In the second step, we derive an optimised model on each specific task from the global pattern with only a few local training data. Compared with traditional multi-task learning methods, SUM shows advantages of generalisation ability on distant tasks. It can be applied on any multi-task models with the gradient descent as its optimiser regardless if the prediction function is linear or not. Moreover, we can harness the model to enable traditional prediction model to make coKriging. The experiments on public datasets have suggested that our framework, when combined with current multi-task models, has a conspicuously better prediction result when the task number is small compared to low-rank tensor learning, and our model has a quite satisfying outcome when adjusting the current prediction models for coKriging., Comment: 5 pages

Published
2019

11. Blockchain-Enabled Hierarchical Federated Learning in Resource-Constrained Power Systems

Author

Yang, Huifeng, Chen, Liandong, Cheng, Kai, Zhang, Lei, Shen, Peipei, Chen, Jiewei, Guo, Shaoyong, Li, Qichen, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Liu, Qi, editor, Liu, Xiaodong, editor, Cheng, Jieren, editor, Shen, Tao, editor, and Tian, Yuan, editor

Published
2022
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23. Experimental study on bond performance between carbon/glass-hybrid-fiber-reinforced polymer bars and concrete.

Author

Liang, Mengmeng, Yu, Yixun, Xu, Gaojie, Li, Qichen, and Pan, Yunfeng

Abstract

Coating GFRP bars with a layer of carbon fibers containing carbon/glass-hybrid-fiber-reinforced polymer (HFRP) bars has been proven to improved interlaminar shear durability. Thus, the bond performance of the HFRP bar-concrete interface depends on the behavior of the HFRP-reinforced concrete structure. In this context, the study investigates the effects of the compressive strength of concrete and the embedded length of HFRP bars on the bond behavior of the HFRP bar-concrete interface and compares the results with the data on the interfacial bond of GFRP bar to concrete. The results demonstrate that all the specimens fail at the FRP bar–concrete interface under the pullout. The bond strength and bond stiffness of the HFRP bar–concrete composites decrease with an increase in the embedded length of the HFRP bar from 4 to 10 times its diameter. Raising the compressive strength of the concrete enlarges the bond strength and bond stiffness of the HFRP bar–concrete composites. Furthermore, the outer layer of carbon-fiber on the GFRP bar decreases the impact of the embedded length of the HFRP bar on the bond strength and bond stiffness of the HFRP bar–concrete composites. Finally, the improved modified mBPE model can accurately predict the bond stress–slip relationship of GFRP/BFRP/HFRP bar–concrete composites. [ABSTRACT FROM AUTHOR]

Published
2024
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26. Exploring the Relationship Between Usage of Collegiate Recreation Facilities and Academic Achievement.

Author

Das, Rajeeb, Boren, Shaun, Li, Qichen, and Dempsey, Marty

Subjects
ACADEMIC achievement, GRADE point average, LOGISTIC regression analysis, COLLEGE students, GENDER, FACILITY management
Abstract

The purpose of this study was to explore grade point average among college students with varied usage levels of collegiate recreation (CR) facilities. Turnstile data was paired with demographic and academic data from university databases, including degree seeking status, to add a quasi-experimental component to the study (first time in college (FTIC) versus non-degree seeking students). Multinomial logistic regression analyses identified differences in grade point average for CR usage level, gender, and race/ethnicity (p <.0001). It was determined that high CR users were 3.1 (95% CI = 2.16, 4.39) times more likely to have a high GPA (≥3.8) versus low users. Results corroborate prior evidence that high users of collegiate recreation facilities are more likely to also have high academic achievement. [ABSTRACT FROM AUTHOR]

Published
2021
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37. Service life prediction method for wheel-hub-bearing under random multi-axial wheel loading

Author

Lihui Zhao, Li Qichen, Jinzhi Feng, and Songlin Zheng

Subjects
Coupling, Bearing (mechanical), business.industry, Iterative method, General Engineering, 020101 civil engineering, 02 engineering and technology, Structural engineering, Dynamic load testing, 0201 civil engineering, law.invention, 020303 mechanical engineering & transports, 0203 mechanical engineering, Tapered roller bearing, Joint probability distribution, law, Service life, Bending moment, General Materials Science, business, Mathematics
Abstract

In view of the problem that the current bearing life evaluation is mainly based on the constant load condition, and the dynamic coupling effects of radial force, axial force and bending moment are less considered, leading to the great difference between the actual service life and the theoretical life of the bearing, this paper proposed a method of wheel-hub-bearing service life prediction under multi-axial wheel loading. Based on the data of six-dimensional force measured in the proving ground, the coupling frequency relation between multi-axis loads is determined by joint distribution counting to determine the times of damage load. Based on the deformation coordination relationship between the bearing roller and the raceway, and considering the influence of the angular misalignment of the roller, the calculation model of the instantaneous contact load of the tapered roller bearing is established. Combining the count result of joint distribution of multi-axial loads and the calculation model of contact loads, Newton-Raphson(N-R) iterative method was used to solve the bearing circumferential contact load sequence. Based on the modified L-P theory, the equivalent dynamic load of the bearing corresponding to the multi-axial load is obtained, and the validity of the results is verified by comparing with the simulation results of Romax. Combined with equivalent dynamic load of bearing, joint distribution count result and linear damage accumulation criterion, the life calculation of wheel-hub-bearing under multi-axial random road load in the proving ground was completed, and the accuracy of the results and rationality of the method were verified by bench test. Thus, it can provide reference for the design and selection of wheel-hub-bearing and life prediction.

Published
2021

40. Tailoring Superconductivity with Quantum Dislocations

Author

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Mechanical Engineering, Massachusetts Institute of Technology. Department of Nuclear Science and Engineering, Massachusetts Institute of Technology. Department of Physics, Mingda Li, Qichen Song, Te-Huan Liu, Laureen Meroueh, Gerald D. Mahan, Mildred S. Dresselhaus, and Gang Chen, Li, Mingda, Song, Qichen, Liu, Te Huan, Dresselhaus, Mildred, Chen, Gang, Mahan, Gerald D., Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Mechanical Engineering, Massachusetts Institute of Technology. Department of Nuclear Science and Engineering, Massachusetts Institute of Technology. Department of Physics, Mingda Li, Qichen Song, Te-Huan Liu, Laureen Meroueh, Gerald D. Mahan, Mildred S. Dresselhaus, and Gang Chen, Li, Mingda, Song, Qichen, Liu, Te Huan, Dresselhaus, Mildred, Chen, Gang, and Mahan, Gerald D.

Abstract

Despite the established knowledge that crystal dislocations can affect a material’s superconducting properties, the exact mechanism of the electron-dislocation interaction in a dislocated superconductor has long been missing. Being a type of defect, dislocations are expected to decrease a material’s superconducting transition temperature (T[subscript c]) by breaking the coherence. Yet experimentally, even in isotropic type I superconductors, dislocations can either decrease, increase, or have little influence on T[subscript c]. These experimental findings have yet to be understood. Although the anisotropic pairing in dirty superconductors has explained impurity-induced T[subscript c] reduction, no quantitative agreement has been reached in the case a dislocation given its complexity. In this study, by generalizing the one-dimensional quantized dislocation field to three dimensions, we reveal that there are indeed two distinct types of electron-dislocation interactions. Besides the usual electron-dislocation potential scattering, there is another interaction driving an effective attraction between electrons that is caused by dislons, which are quantized modes of a dislocation. The role of dislocations to superconductivity is thus clarified as the competition between the classical and quantum effects, showing excellent agreement with existing experimental data. In particular, the existence of both classical and quantum effects provides a plausible explanation for the illusive origin of dislocation-induced superconductivity in semiconducting PbS/PbTe superlattice nanostructures. A quantitative criterion has been derived, in which a dislocated superconductor with low elastic moduli and small electron effective mass and in a confined environment is inclined to enhance T[subscript c]. This provides a new pathway for engineering a material’s superconducting properties by using dislocations as an additional degree of freedom. Keywords: Dislocations; disordered superconducto, United States. Department of Energy. Office of Basic Energy Sciences (Grant DE-SC0001299), United States. Department of Energy. Office of Basic Energy Sciences (Grant DE-FG02-09ER46577), United States. Defense Advanced Research Projects Agency (Award HR0011-16-2-0041)

Published
2018

42. 辣道至简：老干妈陶华碧的经营智慧

Author

李琦晨, Li Qichen, 李琦晨, and Li Qichen

Abstract

陶华碧年轻丧夫，独自远奔广东打工，带大两个儿子； 42岁开始创业，卖过米豆腐、米粉、凉面，最后顺带做了辣椒酱； 她不识字，但记忆力惊人，财务状况随口说来； 极少接受采访，这次老干妈终于开口。 从小店到辣椒酱帝国，这是一个女人的创业征途，陶华碧如何带领老干妈实现连续18年业绩增长，破40亿的年销售额，她的产品战略、国际布局、财务思想、资本观在互联网思维风靡的时代如何独树一帜，凭什么令人刮目相看。

Published
2015

44. Open source Java-based ECG analysis software and Android app for Atrial Fibrillation screening

Author

Oster, Julien, Behar, Joachim, Colloca, Roberta, Li, Qichen, Li, Qiao, Clifford, Gari D., Imagerie Adaptative Diagnostique et Interventionnelle (IADI), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Lorraine (UL), Institute of Biomedical Engineering [Oxford] (IBME), University of Oxford [Oxford], Université de Lorraine (UL)-Institut National de la Santé et de la Recherche Médicale (INSERM), and UL, IADI

Subjects
Abstracts, [SDV.MHEP] Life Sciences [q-bio]/Human health and pathology, Detectors, [SDV.MHEP]Life Sciences [q-bio]/Human health and pathology
Abstract

International audience; The development of mHealth applications could facilitate the decrease of the healthcare costs in both high income and low to middle income regions. However, it is essential that mHealth software is validated on public databases. Moreover, public scrutiny of the algorithms is likely to lead to faster and lower cost innovation. In this paper, we therefore present a novel Java-based Android application offering advanced Electrocardiogram (ECG) processing techniques, including signal quality analysis and Atrial Fibrillation (AF) screening.

Published
2013

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