Xiao Fu's Homepage
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Xiao Fu, Ph.D.
Associate Professor
School of Electrical Engineering and Computer Science
Oregon State University
3003, Kelley Engineering Center
Corvallis, OR, 97331, United States
(xiao.fu(AT)oregonstate.edu)
Links: Google Scholar, OSU AI Program, Signal Processing Group
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News and Updates
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In this work, we study using conditions that were proposed for structured matrix factorization (X=AS) to underpin identifiability of nonlinear mixtures (x=f(s)). It turns out that there is an interesting connection: the sufficiently scattered condition often used for SMF corresponds to diverse influence of latents onto the observed features. This enables unique identification by maximizing the volume of the Jacobian of the mixing function.
Jul. 2024: Check out our new submission on arXiv. This work reviewed the developments of noisy label crowdsourcing from a signal processing perspective, connecting ideas, formulations, and algorithms in this domain to techniques that are widely used in SP, e.g., NMF and tensor decomposition.
Sep 2023: I am humbled and honored to have received the Engelbrecht Early Career Award from the College of Engineering, Oregon State University. Thank you COE for the recognition. Many thanks to my students, collaborators, mentors and my nominator.
Sep 2023: Shahana defended her dissertation in July 2023! In Dec. 2023, Shahana will join the AI Initiative of the University of Central Florida as a Tenure-Track Assistant Professor (joint appointment with the Department of ECE and the Department of CS). Congratulations Shahana! We are proud of you and looking forward to seeing more accomplishments of yours.
June 2023, I visited KU Leuven, Belgium, hosted by Prof. Aritra Konar and Prof. Lieven De Lathauwer.
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April 2023, Tri and Shahana have their ICML 2023 papers accepted!
Mar. 2023, another work by Sagar has been accepted to IEEE Transactions on Signal Processing:
Jan. 2023, Sagar's work has been accepted to IEEE Transactions on Signal Processing:
S. Shrestha, X. Fu, and M. Hong, ‘‘Optimal Solutions for Joint Beamforming and Antenna Selection: From Branch and Bound to Graph Neural Imitation Learning’’, IEEE Transactions on Signal Processing, accepted, Jan. 2023
The work studies a graph neural network-based acceleration method for provably solving the joint beamforming and antenna selection problem, under a uni-cast setting. An interesting take-away is that, under reasonable conditions, this mixed integer and nonconvex program optimally and efficiently with the help of neural imitation learning.
We showed that the graph neural imitation learning approach can reduce the branch and bound method's computational complexity from an exponential order to a linear one, with high probability.
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Jan. 2023, Shahana and Tri's paper has been accepted to ICLR 2023:
Jan. 2023, Our paper has been accepted to IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing:
Jan. 2023, I gave a talk at the Institute of Pure and Applied Mathematics (IPAM) at UCLA. The talk is based on our ICLR2022 work:
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2022 IEEE Signal Processing Society Best Paper Award: H. Sun, X. Chen, Q. Shi, M. Hong, X. Fu, and N.D. Sidiropoulos, ‘‘Learning to Optimize: Training Deep Neural Networks for Interference Management,’’ in IEEE Transactions on Signal Processing, vol. 66, no. 20, pp. 5438-5453, 15 Oct.15, 2018.
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2022 IEEE Signal Processing Society Donald G. Fink Overview Paper Award: N.D. Sidiropoulos, L. De Lathauwer, X. Fu, K. Huang, E.E. Papalexakis, and C. Faloutsos, ‘‘Tensor Decomposition for Signal Processing and Machine Learning’’, IEEE Transactions on Signal Processing, vol. 65, no. 13, pp. 3551-3582, July 1, 2017
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The paper shows that post-nonlinear mixture (PNL) learning does not need stringent conditions (e.g., statistical independence of the latent components as often used in nonlinear ICA) for model identifiability. The lesson learned in the paper is that if the latent model is a low-rank matrix, then the PNL is identifiable.
May. 2022, Our group has received the National Science Foundation Faculty Early Career Development Program Award (NSF CAREER Award). This award will support us to develop exciting nonlinear factor analysis tools for machine learning and signal processing tasks like unsupervised representation learning, self-supervised learning, hyperspectral imaging, and brain signal processing; see the public information from NSF: Click Here
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Q. Lyu and X. Fu, ‘‘Identifiability-Guaranteed Simplex-Structured Post-Nonlinear Mixture Learning via Autoencoder’’, IEEE Transactions on Signal Processing, accepted, June 2021. In this paper we ask a fundamental question: When and how can we identify the matrix factorization model under unknown post-nonlinear distortions; i.e., given y=g(As) with unknown element-wise nonlinear distortion g(.), how to learn A and s in an unsupervised manner? Check out the paper for our most recent take on this problem.
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H. Sun, W. Pu, X. Fu, T.-H. Chang, and M. Hong, ‘‘Learning to Continuously Optimize Wireless Resource in a Dynamic Environment: A Bilevel Optimization Perspective’’, submitted to IEEE Transaction on Signal Processing, April, 2021.
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Trivia: My first journal publication 8 years ago was in Signal Processing. See: K. K. Lee, W.-K. Ma, X. Fu, T.-H. Chan, and C.-Y. Chi, “A Khatri-Rao subspace approach to blind identification of mixtures of quasi-stationary sources,” Signal Processing, vol. 93, no. 12, pp. 3515-3527, Dec 2013 (special issue in memory of Alex B. Gershman). (Matlab Code)
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At least two Ph.D. positions available! Click here for more information. We welcome applicants who are interested in:
deep unsupervised learning,
social network analysis,
statistical machine learning,
hyperspectral imaging,
tensor/nonnegative matrix factorization,
deep learning for wireless communication.
Applicants please send (i) CV, (ii) sample research papers, and (iii) research statement to Dr. Xiao Fu (xiao.fu@oregonstate.edu). Materials received before Jan 1, 2021 will be considered with high priority.
June 2020: Check out this submission ‘‘Hyperspectral super-resolution via interpretable block-term tensor modeling’’. Here we offer an alternative to our previous work on tensor based hyper spectral super-resolution (Kanatsoulis, Fu, Sidiropoulos, and Ma 2018). The new model has two advantages: 1) the recoverability of the super-res. image is guaranteed (as in other tensor models); 2) the latent factors of this model has physical interpretations (but other tensor models do not). The second property allows us to design structural constraints for performance enhancement.
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June 2020: Our overview paper on structured tensor and matrix decomposition has been accepted in IEEE Signal Processing Magazine, special issue on ‘‘Non-Convex Optimization for Signal Processing and Machine Learning’’. We discussed a series developments in optimization tools for tensor/matrix decomposition with structural requirements on the latent factors. We introduced inexact BCD, Gauss–Newton (foundation of Tensorlab), and stochastic optimization (with ideas from training deep nets) for tensor and matrix decomposition.
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B. Yang, X. Fu, Kejun Huang, N. D. Sidiropoulos, ‘‘Learning Nonlinear Mixture: Identifiability and Algorithm’’ has been accepted by IEEE Transactions on Signal Processing.
Mar. 2020: a number of papers accepted!
X. Fu, S. Ibrahim, H.-T. Wai, C. Gao, and K. Huang, ‘‘Block-Randomized Stochastic Proximal Gradient for Low-Rank Tensor Factorization’’, IEEE Transactions on Signal Processing, accepted, Mar 2020. Matlab Code
K. Tang, N. Kan, J. Zou, C. Li, X. Fu, M. Hong, H. Xiong ‘‘Multi-user Adaptive Video Delivery over Wireless Networks: A Physical Layer Resource-Aware Deep Reinforcement Learning Approach’’, IEEE Transactions on Circuits and Systems for Video Technology, accepted, Mar 2020.
R. Wu, W.-K. Ma, X. Fu and Q. Li, ‘‘Hyperspectral Super-Resolution via Global-Local Low-Rank Matrix Estimation’’, IEEE Transactions on Geoscience and Remote Sensing, accepted, Mar 2020
Y. Shen, X. Fu, G. B. Giannakis, and N. D. Sidiropoulos, ‘‘Topology Identification of Directed Graphs via Joint Diagonalization of Correlation Matrices,’’ the IEEE Transactions on Signal and Information Processing over Networks, Special Issue on Network Topology Inference, accepted, Mar. 2020
Mar. 2020, Undergraduate Research Assistantship Available: I am looking undergraduate research assistants in EECS at Oregon State University who are interested in statistical machine learning. Please send me your C.V. and transcripts if you are interested in working with me starting summer or Fall 2020 (or Winter 2021). The research experience program will typically be 10 weeks (one term).
Mar. 2020, Ph.D. Position available (Research Assistantship): I have always been looking for PhD students who are interested in signal processing and machine learning, especially matrix/tensor factorization models, deep unsupervised learning, and optimization algorithm design. Please send me your C.V. and transcripts (and papers if you have published your work) if you are interested in working with me starting Fall 2020. I would expect some details for why you're interested in my group.
Jan. 2020: Two journal papers have been submitted!
S. Ibrahim, X. Fu, and X. Li, ‘‘On recoverability of randomly compressed tensors with low CP rank’’, submitted to IEEE Signal Processing Letters, Jan. 2020.
X. Fu, N. Vervliet, L. De Lathauwer, K. Huang and N. Gillis, ‘‘Nonconvex optimization tools for large-scale tensor and matrix decomposition with structured factors’’, submitted to IEEE Signal Processing Magazine, Jan. 2020.
Dec. 2019: Shahana has her own website online! Please click here to take a look. She has posted the demo of our stochastic tensor decomposition algorithm (BrasCPD and AdaCPD).
Dec. 2019: Our paper ‘‘Link Prediction Under Imperfect Detection: Collaborative Filtering for Ecological Networks’’ has been accepted by IEEE Transactions on Knowledge and Data Engineering! This paper is co-authored by Xiao, Eugene Seo, Justin Clarke, and Rebecca Hutchinson, all from EECS at Oregon State! Justin was with us as an undergraduate student by the time of submission, and he is now at UMass for his graduate degree. Congratulations, team!
Dec. 2019: Shahana presented her first work at NeuriPS 2019, Vancouver, Canada! See the details in the paper ‘‘Crowdsourcing via Pairwise Co-occurrences: Identifiability and Algorithms.’’
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Nov. 2019: Two papers were submitted
K. Tang, N. Kan, J. Zou, C. Li, X. Fu, M. Hong, H. Xiong ‘‘Multi-user Adaptive Video Delivery over Wireless Networks: A Physical Layer Resource-Aware Deep Reinforcement Learning Approach’’, submitted to IEEE Transactions on Circuits and Systems for Video Technology.
G. Zhang, X. Fu, J. Wang, X.-L. Zhao, and M. Hong, ‘‘Spectrum Cartography via Coupled Block-Term Tensor Decomposition’’, submitted to IEEE Transactions on Signal Processing.
Oct. 2019: Trung Vu is awarded the Best Student Paper Award (second prize) at IEEE International Workshop on Machine Learning for Signal Processing, October 13-16, 2019 Pittsburgh, PA, USA! The award is given to a collaborative paper of Trung Vu, Raviv Raich and Xiao Fu titled ‘‘On Convergence of Projected Gradient Descent for Minimizing a Large-scale Quadratic over the Unit Sphere’’. Congratualations, Trung!
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Oct. 2019: The paper ‘‘Tensor Completion from Regularly Sampled Data’’ has been accepeted by IEEE Transactions on Signal Processing!
Sep 2019: First good news in September! Shahana's first NeuriPS paper ‘‘Crowdsourcing via Pairwise Co-occurrences: Identifiability and Algorithms’’ (S. Ibrahim, X. Fu, N. Kargas, and K. Huang) has been accepted! This year NeuriPS has a record-breaking 6743 submissions, and only 1428 were accepted (= 21%).
June 2019: We have submitted a paper (with Ryan, Ken, Qiang) titiled ‘‘Hyperspectral Super-Resolution via Global-Local Low-Rank Matrix Estimation’’ to IEEE Transactions on Geoscience and Remote Sensing.
June 2019: Our paper (with Cheng and Nikos) ‘‘Algebraic Channel Estimation Algorithms for FDD Massive MIMO systems’’ has been accepeted to IEEE Journal of Selected Topics in Signal Processing!
June 2019: We have submitted a paper titled ‘‘Link Prediction Under Imperfect Detection: Collaborative Filtering for Ecological Networks’’ to IEEE Transactions on Knowledge and Data Engineering. In this work, we proposed a statistical generative model for ecological network link prediction. The challenge for this type of networks is that all the observed entries suffer from systematic under estimation–which is very different from online recommender systems. This is a collaborative research with Eugene Seo, Justin Clarke, and Rebecca–all from EECS at Oregon State.
May 2019: Cheng Gao sucessfully defended his thesis and now is a Master of Science!
May 2019: Shahana Ibrahim is awarded a travel grant (sponsored by the National Science Foundation (NSF)) to IEEE Data Science Workshop in Minneapolis, MN, United States. Shahana has a paper ‘‘Stochastic optimization for coupled tensor decomposition with applications in statistical learning’’ accepted to the conference. Congratulations Shahana!
April 2019: Our paper (with Kejun) ‘‘Detecting Overlapping and Correlated Communities: Identifiability and Algorithm’’ has been accepted to ICML 2019! This work proposes a new community detection method that has correctness guarantees for identifying the popular mixed membership stochastic blockmodel (MMSB). Many existing methods rely on the existence of ‘‘pure nodes’’ (i.e., nodes in a network that only belong to one community) to identify MMSB. This assumption may be a bit restrictive. Our method leverage convex geometry-based matrix factorization to establish identifiability under much milder conditions.
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Mar. 2019: The IEEE Communications Society (ComSoc) has provided a list of papers for “Best Readings in Machine Learning in Communications”. Our paper (see below) is included in this list for ‘‘resource allocation’’.
H. Sun, X. Chen, Q. Shi, M. Hong, X. Fu, and N. D. Sidiropoulos, ‘‘Learning to Optimize: Training Deep Neural Networks for Interference Management,’’ IEEE Transactions on Signal Processing, vol. 66, no. 20, pp. 5438-5453, October 2018.
Mar. 2019, Check out this new submission: ‘‘Tensor Completion from Regular Sub-Nyquist Samples’’.
Jan. 2019: Check out this new submission: ‘‘Block-Randomized Stochastic Proximal Gradient for Low-Rank Tensor Factorization’’. This work uses a combination of randomized block coordinate descent and stochastic proximal gradient to decompose large and dense tensors with constraints and regularizations. The complexity saving is quite surprising. The total number of MTTKRPs (which dominates the CPD complexity) needed for the proposed algorithm is very small (see BrasCPD and AdaCPD in the figure).
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Jan. 2019, Check out the new paper: ‘‘Learning Nonlinear Mixtures: Identifiability and Algorithm’’. In this work we push forward parameter identifiability of linear mixture models (LMM) to nonlinear ones. LMM finds many applications in blind source separation-related problems, e.g., hyperspectral unmixing and topic mining. In practice, however, the mixing process is hardly linear. This work studies a fundamental question: if there is nonlinearity imposed upon an LMM, can we still identify the underlying parameters of interest? The interesting observation of our work is that: under some conditions, nonlinearity can be effectively removed and the problem will boil down to an LMM identification problem — for which we have tons of tools to handle.
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Oct. 2018, our paper ‘‘Nonnegative Matrix Factorization for Signal and Data Analytics: Identifiability, Algorithms, and Applications’’, has been accepted in IEEE Signal Processing Magazine as a feature article ! This article talks about intuitions, insights, and most recent results behind NMF identifiability theories. Cool applications of NMF can also be found here.
Sep 2018: Another TSP paper accepted! Check out the arXiv pre-print ‘‘Structured SUMCOR Multiview Canonical Correlation Analysis for Large-Scale Data’’.
Sep 2018: Our first IEEE TKDE paper has been accepted! The paper ‘‘Efficient and Distributed Generalized Canonical Correlations Analysis for Big Multiview Data’’ comes from a collaborative work with CMU (Prof. Christos Faloutsos and Prof. Tom Mitchell). Now the team members are spread across the U.S. and the world (OSU,UFL,CMU,UVA,UCR,IIS). Congratualations to all! The full paper will be uploaded soon.
Sep 2018: Another TSP paper accepted! Check out the arXiv pre-print ‘‘Tensor-Based Channel Estimation for Dual-Polarized Massive MIMO Systems’’.
Sep 2018: Our paper ‘‘Hyperspectral super-resolution: A coupled tensor factorization approach’’ has been accepted to IEEE Transactions on Signal Processing!
Sep 2018: We welcome our new group members Ms. Shahana Ibrahim and Mr. Hang Xiao. Wish everybody a wonderful journey ahead!
Jul 2018: We have just submitted a journal paper to IEEE Transactions on Smart Grid. See the Pre-print here:
June 2018: I gave a talk in the College of Mathematical Science at University of Electronic Science and Technology of China (UESTC), Chengdu, China. The title is ‘‘Hyperspectral Super-Resolution: A Coupled Tensor Factorization Approach’’. See the slides here. The pre-print of the paper is here. Will also be giving this talk at Chongqing University on Jul. 13.
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May 2018: New paper ‘‘Tensor-Based Channel Estimation for Dual-Polarized Massive MIMO Systems’’ has been uploaded to arXiv.
April 2018: the paper ‘‘Anchor-free correlated topic modeling,’’ has been accepted to IEEE Transactions on Pattern Analysis and Machine Intelligence.
April 2018: New write-up ‘‘Hyperspectral super-resolution: A coupled tensor factorization approach’’ has been uploaded. We propose the first identifiability-guaranteed hyperspectral super-resolution method based on tensor factorization in this wrok.
Mar 2018: Check out this new tutorial paper for NMF identifiability, algorithms, and applications: ‘‘Nonnegative Matrix Factorization for Signal and Data Analytics: Identifiability, Algorithms, and Applications’’.
Feb 2018: Check out our new write-up: K. Huang, X. Fu, and N. D. Sidiropoulos, ‘‘Learning Hidden Markov Models from Pairwise Co-occurrences with Applications to Topic Modeling’’.
Feb 2018: Five papers have been accepted to ICASSP 2018, Calgary, Canada, April 2018 — congratulations to all!
Jan 2018: Check out our AAAI 2018 paper: ‘‘‘‘On Convergence of Epanechnikov Mean Shift.’’
Dec. 2017: Here are some newly submitted articles addressing several different topics:
Nov. 2017: Two papers were accepted this week.
T. Qiu, X. Fu, N. D. Sidiropoulos, and D. Palomar, ‘‘MISO Channel Estimation and Tracking from Received Signal Strength Feedback’’ accepted to IEEE Transactions on Signal Processing
K. Huang, X. Fu, and N. D. Sidiropoulos, ‘‘On Convergence of Epanechnikov Mean Shift,’’ to AAAI 2018 (acceptance rate = 25%.)
Sep 2017: Try the Python implementation of our large-scale GCCA work ‘‘Efficient and Distributed Algorithms for Large-Scale
Generalized Canonical Correlations Analysis’’ published at ICDM 2016. The implementation is by Adrian Benton at Johns Hopkins University, who has been doing interesting works in multiview analysis and natural language processing.
Aug 2017: Check out our new write-up ‘‘On identifiability of nonnegative matrix factorization’’ which was submitted to IEEE Signal Processing Letters.
July 2017: Our paper ‘‘Inexact alternating optimization for phase retrieval in the presence of outliers’’ has been accepted to IEEE Transactions on Signal Processing.
July 2017: We have recently submitted several papers:
X. Fu , K. Huang, E.E. Papalexakis, H. Song, P. Talukdar, N. D. Sidiropoulos, C. Faloutsos, and T. Mitchell,‘‘Efficient and Distributed Generalized Canonical Correlation Analysis for Big Multiview Data’’ to IEEE Transactions on Knowledge and Data Engineering
T. Qiu, X. Fu, N. D. Sidiropoulos, and D. Palomar, ‘‘MISO Channel Estimation and Tracking from Received Signal Strength Feedback’’ to IEEE Transactions on Signal Processing
A. S. Zamzam, X. Fu, E. Dall’Anese and N. D. Sidiropoulos, ‘‘Distributed Optimal Power Flow using Feasible Point Pursuit’’ to IEEE CAMSAP 2017.
April 2017: Our paper‘‘Towards K-Means-Friendly Spaces: Simultaneous Deep Learning and Clustering’’ has been accepted to International Conference on Machine Learning (ICML 2017)!
April. 2017: Our paper titled ‘‘Scalable and flexible MAX-VAR generalized canonical correlation analysis via alternating optimization’’ has been accepted to IEEE Transactions on Signal Processing.
Mar. 2017: I gave a tutorial at ICASSP 2017 together with Prof. Nikos Sidiropouos, Prof. Vagelis Papalexakis (University of California Riverside) and Prof. L. De Lathauwer (KU Leuven). The title is ‘‘ Tensor Decomposition for Signal Processing and Machine Learning ’’ which is based on our IEEE Transactions on Signal Processing overview paper. Check out the slides and the camera-ready paper.
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Sep., 2016: Our paper ‘‘Efficient and Distributed Algorithms for Large-Scale
Generalized Canonical Correlations Analysis’’ has been accepted by IEEE Internatial Conference on Data Mining (ICDM 2016)! This year ICDM will be held in the week right after NIPS, also in Barcelona. The acceptance rate of ICDM this year is 19.6%.
Aug., 2016: Our paper ‘‘Anchor-Free Correlated Topic Modeling: Identifiability and Algorithm’’ has been accepted to the Thirtieth Annual Conference on Neural Information Processing Systems (NIPS). This year NIPS will be held in Decemeber in Barcelona
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