Sijie Ji

Schmidt Science Fellow

California Institute of Technology

I am a Schmidt Science Fellow currently working with Prof. Wei Gao in the Division of Engineering and Applied Science at California Institute of Technology. I also have a joint appointment with UCLA, working with Prof. Mani Srivastava. I obtained my Ph.D. from Nanyang Technological University in 2023, under the guidance of Prof. Mo Li.

I am broadly interested in sensing, deep learning, ubiquitous computing, and their applications in digital healthcare systems, cyber-physical systems, and next-generation AIoT systems.

I am open to collaborations and discussions on these areas, drop me an email if you are interested in working together:
LLMs+CPS: LLMs and its applications in cyber-physical systems, mobile computing and human-computer interaction.
AI+Wireless: Wireless Sensing, Wireless Communication, CSI Feedback, Semantic Communication, and ISAC.
Multimodal/Embodied AI: Multimodal sensor data fusion and reasoning, robotics and autonomous systems

In addition, if you are a student from underrepresented groups or in need, you can fill out this form. I'm more than willing to chat about research, grad school, or anything else to offer assistance to the best of my ability.

News

  • [06/25] Invited to serve as TPC member of SenSys'26. Welcome to submit papers!
  • [05/25] LLM + Mental Health papers are accepted by SenSys (poster), ACL 2025. Congrats to the team!
  • [05/25] Invited to serve as TPC member of MobiCom Demo, MobiCom Poster and BodySys 2025, which will be co-located with ACM UbiComp 2025 in Finland. Welcome to submit papers!
  • [04/25] Invited to serve as a co-Chair for the BuildSys'25. Welcome to submit papers!
  • [04/25] Papers are accepted to ACM IMWUT / Ubicomp, IEEE Communications Magzine, ICC. Congrats to Luca, Senthil and Man!
  • [02/25] Invited to serve as TPC member of EMSOFT, ESWeek'25
  • [01/25] Give an invited seminar at UC Merced.
  • [01/25] NeurIT is accepted by ICRA 2025. Congrats to Xinzhe!
  • [12/24] Invited to serve as FMSys 2025 TPC and CoNEXT'25 Shadow TPC. Welcome to submit papers!
  • [11/24] Invited to serve as HumanSys 2025 General co-Chair. Welcome to submit papers!
  • [10/24] Invited to serve as MobiSys 2025 TPC. Welcome to submit papers!
  • [07/24] Give an invited talk at Peking University.
  • [07/24] RS-BNN is accepted by IEEE TVT.
  • [06/24] Invited to serve as a TPC member for ICPADS'24, and serve as a session chair for ICDCS'24, see you in NYC!
  • [04/24] Honored to join Schmidt Science Fellows 2024 cohort!
  • [04/24] MuSAC is accepted by ICDCS'24.
  • [04/24] Honored to be selected as a CPS Rising Star!
  • [03/24] Check out our new findings on the capability of LLMs for reasoning raw sensor data: Human Activity Recognition and Trajectory Recognition based on IMU data.
  • [02/24] Invited to serve as co-Chair for the 2024 SenSys/BuildSys joint Ph.D. Forum, and serve as an AEC member for Mobicom'24.
  • [12/23] BG-BERT is accepted by ICASSP'24, codes.
  • [10/23] I have been selected for the N2Women Young Researcher Fellowship and will organize the N2Women event at SenSys'23.
  • [10/23] HandFi is accepted by SenSys'23 and has been filed as a patent.
  • [09/23] Join HKU! Hit me up when you are in HK.
  • [09/23] I am honored to be listed in the Singapore 100 Women in Tech.
  • [08/23] Give invited talks at Zhejiang University and Zhejiang Lab.
  • [07/23] Spend a wonderful month at ShanghaiTech University.
  • [06/23] Sucessfully defend my Ph.D. thesis.
  • [01/23] JPTS is accepted by ICC'23.
  • [12/22] Give invited Student Lecture Series Talk: SiFall. Video Avaliable.
  • [10/22] SiFall is accepted by SenSys'22.
  • [01/22] Give invited Student Lecture Series Talk: CLNet. Video Avaliable.
  • [10/21] Clinch the 1st runner-up in the Masked Face Recognition Challenge, ICCV 2021.
  • [07/21] CLNet is accepted by IEEE Wireless Communications Letters.
  • [06/20] Clinch the 2nd runner-up in the AI Meets Beauty Challenge, ACM MM 2020.
  • [05/20] Clinch the 2nd runner-up in the EmotioNet Challenge, CVPR 2020.


On the way......

Selected Publications

* denotes either a co-first author or a corresponding author. / ^ denotes students I mentored.
Image 1 SenSys

Construct 3D Hand Skeleton with Commercial WiFi

Sijie Ji, Xuanye Zhang^, Yuanqing Zheng, Mo Li
The 21th ACM Conference on Embedded Networked Sensor Systems (SenSys), 2023.
PDF Code Project Page BibTex
Image 1 SenSys

Construct 3D Hand Skeleton with Commercial WiFi

Sijie Ji, Xuanye Zhang^, Yuanqing Zheng, Mo Li
The 21th ACM Conference on Embedded Networked Sensor Systems (SenSys), 2023.
PDF Code Project Page BibTex
Image 1 SenSys

SiFall: Practical Online Fall Detection with RF Sensing

Sijie Ji, Yaxiong Xie, Mo Li
The 20th ACM Conference on Embedded Networked Sensor Systems (SenSys), 2022.
PDF Slides Video BibTex
Image 1 WCL

CLNet: Complex Input Lightweight Neural Network Designed for Massive MIMO CSI Feedback

Sijie Ji, Mo Li
IEEE Wireless Communications Letters, 2021.
PDF Code Video BibTex
Image 1 ICDCS

MuSAC: Mutualistic Sensing and Communication for Mobile Crowdsensing

Sijie Ji, Lixiang Lian, Yuanqing Zheng, Chenshu Wu
The 44th IEEE International Conference on Distributed Computing Systems (ICDCS), 2024.
PDF PPT BibTex

  • [ICASSP 2024] Predicting Adverse Events for Patients with Type-1 Diabetes via Self-supervised Learning
    　  Xinzhe Zheng, Sijie Ji, Chenshu Wu
  • [ICC 2023] JPTS: Enhancing Deep Learning Performance of Massive MIMO CSI Feedback
    　  Sijie Ji, Mo Li
  • [CVPRW 2020] Multiple Transfer Learning and Multi-Label Balanced Training Strategies for Facial AU Detection in the Wild
    　  Sijie Ji, Kai Wang, Xiaojiang Peng, Jianfei Yang, Zhaoyang Zeng, Yu Qiao
  • [MM 2020] Attention-driven Unsupervised Image Retrieval for Beauty Products with Visual and Textual Clues
    　  Jingwen Hou, Sijie Ji*, Annan Wang^
  • [ICCVW 2021] Improving Representation Consistency with Pairwise Loss for Masked Face Recognition
    　  Hanjie Qian, Panpan Zhang, Sijie Ji, Shuxin Cao, Yuecong Xu
  • [IET Radar 2023] (excellent paper award) Joint Location Design and Resource Allocation for Integrated Sensing and Semantic Communication
    　  Yuanhao Cui, Weijie Yuan, Sijie Ji*, Hongming Zhang, Fan Liu, Zhaohui Yang, Zhouyi Wu
  • [DSP 2024] Robust Target Detection of Intelligent Integrated Optical Camera and mmWave Radar System
    　  Chen Zhu, Zhouxiang Zhao, Zejing Shan, Lijie Yang, Sijie Ji, Zhaohui Yang, Zhaoyang Zhang
  • [IEEE TVT] RS-BNN: A Deep Learning Framework for the Optimal Beamforming Design of Rate-Splitting Multiple Access
    　   Yiwen Wang, Yijie Mao, Sijie Ji

Academic Services

Invited Independent Reviewer:
Journal: TON, TMC, TWC, TCOM, IOTJ, TVT, ACM IMWUT, TIOT, CL, WCL, Sensors, Electronics, TSIP
IEEE Internet of Things Journal, IEEE Transactions on Mobile Computing, ACM/IEEE Transactions on Networking, ACM Transactions on Internet of Things, IEEE Transactions on Vehicular Technology, IEEE Transactions on Wireless Communications, IEEE Transactions on Communications, IEEE Communications Letters, IEEE Wireless Communications Letters
Conference: CVPR, GlobeCom, ICC, INFOCOM, AVSS, VTC, AICity 2021/2022/2023 (CVPR Workshop)
Services:
Session Chiar: VTC Fall 2023, ICDCS'24
Teaching Assistant(TA):
CE3005 Computer Networks 2019-2021
CZ3006 Net-Centric Computing AY20/21 (the head of TAs)
Final Year Projects (FYP) Mentor:
Hao Zhe Lim, 2019 Argota Timothy John Tee, 2020 Annan Wang, 2020 Yupeng Huang, 2021 Xuanye Zhang, 2022

Awards & Honors

Scholarship: NTU Research Scholarship, 2018-2022
National Encouragement Scholarship, 2016
Outstanding Student Scholarship, 2013/2015
Janpan Infotec Inc Aunual Scholarship, 2014
Lu Jiaxi Scholarship, 2012
Competition: 2nd Place, Masked Face Recognition Challenge, ICCV21
Silver Medal, Indoor Location Competition 2.0, Kaggle, 2021
Final list(7/1736), AI+Wireless National Artificial Intelligence Competition, 2020
Bronze Medal Award, AI Meets Beauty Challenge, MM2020
Third Place, EmotioNet Challenge, CVPR2020
Third Prize, "Challenge Cup" National College Student Academic Competition, 2017
Second Prize, International Undergraduate Mathematical Contest in Modeling, 2017
Second Prize, International Undergraduate Interdisciplinary Contest in Modeling, 2016
Third Prize, China Undergraduate Mathematical Modeling Competition, 2016
Second Prize, "Challenge Cup" National College Student Business Plan Competition, 2016
Honorable Mention, China "Internet+"​ College Students Innovation and Entrepreneurship Competition, 2016
Honorable Mention, Asia Region, The 39th International Collegiate Programming Contest, 2014
Silver Medal, China Adolescents Science & Technology Innovation Contest(CASTIC), 2011
Honor: CPS Rising Star, 2024
Excellent Paper Award, IET Radar 2023
N2Women Young Researcher Fellowship, SenSys 2023
Singapore 100 Women in Tech, 2023
SenSys Travel Grant, 2022
Excellent Bachelor Thesis, ECNU
Excellent Student Cadre, ECNU
The Most Outstanding Collaboration Awards, NTU

I am a dancer and trader

Dance and the community it fosters have shaped me as a person.


I am a PULSE scholar awarded by Singapore National Arts Council and trained by Frontier Danceland, Singapore.