Dr. Hui Liu

Enrique-Schmidt-Str. 5
Cartesium, Room 2.51
28359 Bremen
+49(0)421-218-64278
hui.liuprotect me ?!uni-bremenprotect me ?!.de
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 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 (finished 2019).
+ 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 intelligent knee bandage system that senses and recognizes users' activities in real-time, utilizing proximity wearable sensors integrated into the bandage (Best Paper Award, Student Author, 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), 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. Two of my papers on high-level HAR feature design (co-author) and music signal processing (first author), respectively, were the Best Paper Finalists (BIOSIGNALS 2022 and SIGMAP 2022). I received the YERUN (Young European Research Universities Network) Research Mobility Award (YRMA) and the CAMPUSiDEEN Public Choice Award (2022).
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
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
Job Information
Student Assistant/Bachelor-/Master-Thesis: Software Porting on Windows/Android (2022)
Bachelor-/Master-Thesis: Optimal individual song key determination with statistical support of information retrieval (2022)
Bachelor-/Master-Thesis: Automatic singing difficulty analysis of songs with statistical support of information retrieval (2022)
Bachelor-/Master-Thesis: Wearable sensor-based detection of active fingers for interactive piano education (2022)
Bachelor-/Master-Thesis: Real-time Human Activity Recognition Using Smartphones (2022)
Bachelor-/Master-Thesis: Real-time Human Activity Recognition with Virtual Reality (2022)
Bachelor-/Master-Thesis: Comparison of manual, semi-automated, and automatic segmentation of human activity data (2022)
Academic Activities and Contributions
Guest Editor
(MDPI) Sensors
Your contribution is welcome: Sensors for Human Activity Recognition Edition II
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
(ISPRS) International Journal of Geo-Information
(MDPI) Biosensors
- (MDPI) Sensors
(MDPI) Applied Sciences
(MDPI) Biomedicines
(MDPI) Entropy
(MDPI) Electronics
(MDPI) Micromachines
(MDPI) Informatics
(MDPI) Sports
(MDPI) Information
(IEEE) BHI-BSN
YERUN (Young European Research Universities Network)
YERUN Research Mobility Awards (YRMA), 2022
Universidade Nova de Lisboa (Lisbon, Portugal)
- Erasmus Teaching Staff Mobility, 2018
Biosignals Notebooks
Verein der CDHAW-Absolventen und Mitglieder der Tongji-Universität (Düsseldorf)
- Invited Speaker: Academics and Art, 2018
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 2023 - 16th International Joint Conference on Biomedical Engineering Systems and Technologies (Lisbon, Portugal)
- Session Chair
BIOSTEC 2019 - 12th International Joint Conference on Biomedical Engineering Systems and Technologies (Prague, Czech)
- Tutorial: From Offline towards Real-Time
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

Courses
Hot Topics in Sensors and Human Activity Research
Thursday 14:00 – 16:00
Biosignals and User Interfaces
Tuesday 14:15 – 16:15
Wednesday 16:15 – 17:15
- Scoreboard_2020
Selected Topics of Cognitive Systems
Fundamentals of Machine Learning (Partially: Clustering)
Software Project II
Bachelor Project: RoboARinth (Winter Semester 2020/2021, Summer Semester 2021)