Dr. Hui Liu

Hui Liu

Enrique-Schmidt-Str. 5
Cartesium, Room 2.14
28359 Bremen


hui.liuprotect me ?!uni-bremenprotect me ?!.de


Google Scholar


I studied electrical engineering at the Technical University of Berlin (Dipl.-Ing., 2009) and information and communication systems at Shanghai Jiao Tong University (M.Sc., 2011). Since 2016, I have been a researcher for biosignal processing, human activity recognition, virtual reality, and music information retrieval at the Cognitive Systems Lab of the University of Bremen, where I received my Ph.D. (2021). I am co-responsible for three multipartner projects: Arthrokinemat (intelligent knee bandage), IntEL4CoRo (interactive learning for cognitive robotics), and NF-BWB (young talent development). I developed the first smart knee bandage that recognizes users' activities in real-time  (Best Student Paper, BIODEVICES 2019) and proposed Motion Units, an activity modeling method with interpretability, generalizability, and expandability, rationalizing kinesiology and speech recognition knowledge into human activity research (2021). I collected and released the 19-channel, 22-activity, 20-subject human activity dataset CSL-SHARE (2021). My two papers on high-level feature design (co-author) and music signal processing (first author) were the Best Paper Finalists (BIOSIGNALS 2022 / SIGMAP 2022). I received the following third-party funding and awards: the Erasmus Teaching Mobility Award (2018), the CAMPUSiDEEN Public Choice Award for advanced sensing and recognition technology (2022), and the YERUN Research Mobility Award (2022/2023).

Recently, my international collaboration has expanded to include research in singing audio processing, orthotics, and exoskeletons, for which a considerable number of topics are carried out in parallel. I always eagerly await new interdisciplinary and cross-border cooperation in various fields!


Research Interests and Keywords

  • Wearables

      • (Wireless) Body Sensor Network (WBSN/BSN)
      • Body Area Network
      • Inertial sensors and Inertial Measurement Unit (IMU)
      • Electromyography (EMG), electrogoniometers, and other sensors
      • Ubiquitous/pervasive computing
      • Facial EMG (fEMG) and Action Unit Recognition (AUR)
    • Big Data

      • Multimodal data visualization
      • Statistical analysis
      • Organization, operation, and post-processing of big data acquisition
      • Automatic and semi-automatic segmentation and annotation
      • Subsequence search
      • Self-similarity matrix and novelty search
      • Open-source human activity dataset sharing CSL-SHARE
    • Digital Signal Processing (DSP)

      • Multisensorial and multichannel biosignal processing
      • Preprocessing and feature extraction
      • Time series processing
      • Biosignals and user interfaces
    • Machine Learning (ML) / Artificial Intelligence (AI)

      • Feature selection and feature space reduction
      • Early fusion and late fusion
      • Hidden Markov Model (HMM)
      • CNN, RNN, and ResNet
      • Model training, decoding, and evaluation
    • Human Activity Recognition (HAR)

      • Human Activity Recognition Research Pipeline: HAR-Pipeline
      • Advanced human activity modeling: Motion Units
      • HAR Software development: Activity Signal Kit (ASK)
      • Real-time end-to-end HAR system: Activity Signal Kit Echtzeit-Decoder (ASKED)
      • On-the-fly plug-and-play HAR functionality: Activity Signal Kit Plug-And-PlAy (ASKPAPA)
      • Internal sensing and wearable computing for HAR
    • Biomedical Engineering (BME)

      • Rehabilitation assistance
      • Arthritis and knee bandage
      • Mobile phone application for auxiliary medical care
      • Virtual Reality (VR) and Mixed Reality (MR) for BME
    • Music Information Retrieval (MIR)

      • Feature extraction of melody pitch statistics
      • MIR-based amateur singing assistance
      • Joint processing of pitch statistics and audio signals

    Hui's supervised students and research assistants (partially) 2023
    Hui's supervised students and research assistants (partially) 2023

    My best research assistants and students (HiWi/thesis/guest)

    Yale Hartmann
    Research assistant 2018 — 2020 (HAR); Bachelor thesis 2019 (full score); Master thesis 2020 (full score) → Ph.D candidate @ CSL
    Anindya Chowdhury
    Research assistant 2019 (statistical models) → Data Analyst @ Fujifilm Europe, Ratingen
    Lennard Mai
    Bachelor thesis 2019 (automatic segmentation of motion data) → Junior Data Engineer @ hmmh, Bremen
    Timo Urban
    Bachelor thesis 2019 (Android APP development for biosignal acquisition, full score) → Software engineer @ TK, Hamburg
    Kilian Luedemann
    Bachelor thesis 2021 (RNN-based fall detection using IF videos) → Software engineer @ RealCore Group, Essen
    Tobias Dellert
    Bacheler thesis 2022 (HRV and inertial signals for real-time workload monitoring in AWS) @ Tbilisi, Georgia → Data Engineer @ WearHealth, Bremen
    Isabel de Almeida Curioso
    Master thesis 2022 (missing data on clinical contexts, 20/20, best of the year) @ Lisbon, Portugal (20/20, best of the year) → Researcher @ Portugal
    Shiyao Zhang
    Research assistant since 2022 (artifact recognition during biosignal acquisition; research group convenor)
    Steffen Lahrberg
    Bachelor thesis 20121 (cross-channel features for direction distinguishment in HAR, full score)
    Wei Wang
    Master thesis 2022 (subsequence search for automatic heart sound segmentation) @ Hannover → IT application developer @ Bosch, Eisenach
    Daniel Faustino de Noronha Osório
    Ph.D. thesis 2023 (pervasive and remote sensing in cardiovascular disease assessment) @ Lisbon, Portugal → Senior Engineer @ PLUX wireless biosignals SA
    Jonas Boule
    Research assistant since 2023 (EEG analysis; EEG and inertial data fusion for HAR)
    Romina Razeghi Oskouei
    Research assistant since 2023 (EMG signal acquisition and processing)
    Ferdinand Rohlfing
    Research assistant since 2023 (ML for EMG-based action unit recognition)
    Anantha Sripada Abhinav Veldanda
    Guest research scholar & Bachelor thesis 2023 (real-time action unit recognition) @ Goa/Bremen (Grade A) → Engineer @ India
    Ciwan Gülpinar
    Bachelor Thesis 2023 (Biosignals in VR) → Master student @ Uni Bremen
    Johann Joachim Keuneke
    Graduation research in progress (multimodal sensors in mobile phone)
    Daniel Ott
    Graduation research in progress (GUI design and user experience analysis for singing assistance)
    Hasanur Jaman Seam
    Graduation research in progress (mobile phone-based HAR)
    Hannes Wehrmann
    Graduation research in progress (HAR-based real-time sonification during sports)
    Rakibul Islam
    Graduation research in progress (GUI design and usability validation of self-similarity-based automatic time-series analysis)
    Thorben Lorenzen
    Graduation research in progress (EMG-based piano playing finger recognition)
    Leon Flaack
    Graduation research in progress (LSTM-based main melody channel detection from MIDI)
    Jiumeng Chen
    Graduation research in progress (foot activity recognition)
    Joel Warnken
    Graduation research in progress (singing pitch detection and intonation training)
    Mohamad Asif Siddiqui
    Graduation research in progress (outlier detection benchmark)
    Mohamad Tofayel Ahmed
    Graduation research in progress (regression benchmark and AI-based correction of fuel cell aging model)
    Arthur Belousov
    Graduation research in progress (piano audio-based automatic score generation)
    Aklima Akter
    Graduation research in progress (advanced data processing for Wi-Fi-based HAR)
    Yvo Muslukus
    Research assistant since 2023 (ML for EMG-based action unit recognition)

    BBDCB23 Foto
    NF-BWB (Bremen Big Data Challenge Basic)

    Research Projects

    BIODEVICES 2019 (Best Paper, Student Author) / CAMPUSiDEEN 2022 (Public Choice Award) / KIT Adaptive Systems Talks 2022 / MindDay 2021
    BIODEVICES 2019 (Best Paper, Student Author) / CAMPUSiDEEN 2022 (Public Choice Award) / KIT Adaptive Systems Talks 2022 / MindDay 2021

    Academic Activities and Contributions

    • Editorial Board

      • Frontiers in Big Data

      • Frontiers in Artificial Intelligence

    • Editor

      • Frontiers in Behavioral Neuroscience

    • Program Chair

      • BIOSIGNALS 2024 (in BIOSTEC 2024) – 17th International Conference on Bio-Inspired Systems and Signal Processing (Rome, Italy)

    • Session Chair

      • HEALTHINF 2022 (in BIOSTEC 2022) – 15th International Conference on Health Informatics (Vienna, Austria)

      • SIGMAP 2022 – 19th International Conference on Signal Processing and Multimedia Applications (Lisbon, Portugal)

      • BIOSTEC 2023 – 16th International Joint Conference on Biomedical Engineering Systems and Technologies  (Lisbon, Portugal)

    • Peer Reviewer

      • For 33 international journals, including Nat. Commn., Biomed. Signal Process. Control, Remote Sens., Front. Physiol., Front. Med., Physiol. Meas., Phys. Scr., Biomimetics, and Biosensors

      • For various conferences, including IEEE BSN and BHI; ACM ICMI, ISWC, and AUTOMOTIVEUI; ITG

    • Universidade Nova de Lisboa (Lisbon, Portugal)

      • Erasmus Teaching Staff Mobility, 2018
    • Verein der CDHAW-Absolventen und Mitglieder der Tongji-Universität (Düsseldorf)

    • BIOSTEC 2019 - 12th International Joint Conference on Biomedical Engineering Systems and Technologies  (Prague, Czech)

    • BBDC 2019 - 4th Bremen Big Data Challenge

      • Big data acquisition, processing, and provision
    • Bremen.AI 2019

      • Demonstration of real-time human activity recognition
      • Demonstration of MR game platform for rehabilitation assistance
    • MindDay 2021

      • Demonstration of intelligent knee bandage
    • KIT Adaptive Systems Talks 2022

      • Invited workshop speaker
    • CAMPUSiDEEN 2022

      • Public Choice Award


    • Hot Topics in Sensors and Human Activity Research

      • Thursday 14:00 – 16:00

    • Biosignals and User Interfaces


    • General: Tuesday 16:00 - 18:00

    • Or by prior appointment via Email