Dr. Hui Liu

Hui Liu

Enrique-Schmidt-Str. 5
Cartesium, Room 2.51
28359 Bremen


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


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I am a researcher at the Cognitive Systems Lab (CSL), University of Bremen, focusing on biomedical engineering, biosignal processing, human activity recognition (HAR), rehabilitation assistance, machine learning (ML), robotics, virtual reality, and music information retrieval (MIR). I was/am co-responsible for the following multi-partner projects:

+ Arthrokinemat, BMWi (Federal Ministry for Economic Affairs and Climate Protection, Germany) — development of a learning, adaptive, sensor-based measurement system to prevent arthrosis activation when the knee joint is overloaded. 
+ ETAP, BMG (Federal Ministry of Health, Germany) — evaluation of semi-automated care processes in long-term care using AI-based movement monitoring as an example.
+ IntEL4CoRo, BMBF (Federal Ministry of Education and Research, Germany) — interactive learning environment for cognitive robotics.

I developed the first mobile system that senses and recognizes its users' movements in real-time, utilizing proximity wearable sensors integrated into a knee bandage, which won the Best Paper Award (Student Author) at BIODEVICES (2019). I invented Motion Units, a human activity modeling method with interpretability, generalizability, and expandability, rationalizing knowledge from kinesiology and automatic speech recognition into HAR research (2021). I collected and shared a 19-channel 22-activity 20-subject human activity dataset CSL-SHARE (Cognitive Systems Lab Sensor-based Human Activity REcordings), applying various types of wearable sensors and a knee bandage as a novel sensor carrier, on which six-hour data of an 11.52-h recording are well segmented, annotated, and post-verified (2021). Demonstrated in many international academic and industrial occasions, our wearable sensor-based activity recognition technologies and systems have been widely recognized. In 2022, I proposed novel variants of the pitch histogram, the merged pitch histogram and the pitch-duration histogram, and successfully applied them to ethnomusicology studies and singing aids. Currently, I have two technology patents pending.

Recently, my international collaboration has expanded to include research in geophysics, disease diagnosis, 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
    • Big Data

      • Multimodal data visualization
      • Statistical analysis
      • Organization, operation, and post-processing of big data acquisition
      • Automatic and semi-automatic segmentation and annotation
      • 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

    Academic Activities and Contributions

    • Editorial Board

      • (Frontiers) ... in Big Data

      • (Frontiers) ... in Artificial Intelligence

    • Editor

      • (Frontiers) ... in Behavioral Neuroscience

    • Peer Reviewer (Journals and Conferences)

      • (Springer Nature) Nature Communications

      • (Springer Nature) Computer Science

      • (Springer) Frontiers of Information Technology & Electrical Engineering

      • (Elsevier) Biomedical Signal Processing and Control

      • (Frontiers) ... in Medicine

      • (Frontiers) ... in Big Data

      • (Frontiers) ... in Artificial Intelligence

      • (MDPI) Biosensors

      • (MDPI) Sensors
      • (MDPI) Applied Sciences

      • (MDPI) Entropy

      • (MDPI) Electronics

      • (MDPI) Micromachines

      • (MDPI) Informatics

      • (IEEE) BHI-BSN

    • YERUN (Young European Research Universities Network) Research Mobility Awards (YRMA)

    • Universidade Nova de Lisboa (Lisbon, Portugal)

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

    • BIOSTEC 2022 - 15th International Joint Conference on Biomedical Engineering Systems and Technologies  (Vienna, Austria)

      • HEALTHINF Session Chair
    • SIGMAP 2022 - 19th International Conference on Signal Processing and Multimedia Applications (Lisbon, Portugal)

      • Session Chair
    • 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
    • CAMPUSiDEEN 2022

      • Public Choice Award
    MindDay 2021
    MindDay 2021
    CAMPUSiDEEN 2022
    CAMPUSiDEEN 2022


    • 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


    Previous publication

    Capacity of Cooperative Ad Hoc Networks with Heterogeneous Traffic Patterns (Hui Liu, Xinbing Wang), In ICC 2011 — IEEE International Conference on Communications, pages 1–5, 2011.