Research And System Design On Speaking Behavior Measurement Of Online PBL Class

Teaching measurement is an important part of teaching research.By quantifying the teaching behavior of teachers and students,it can provide an essential objective data basis for teaching evaluation.PBL(Problem-Based Learning)teaching method is a discussionbased teaching method which is widely used in medical education at home and abroad.During the COVID-19 epidemic,Tongji Medical College of Huazhong University of Science and Technology proposed a teaching research on the difference of student behavior between online PBL class and offline PBL class.This research urgently needs a class behavior measurement system to provide reliable quantitative class behavior data.In this regard,this paper designs and implements an online PBL class speaking behavior measurement system to measure speaking behavior,which is the most basic and important class behavior.To meet the teaching measurement needs of online PBL class,the class speaking behavior measurement system proposed in this paper respectively designs and implements end-to-end class speaking behavior measurement programs for audio and video data formats.The main work of this paper is as follows:(a)Design a data collection and labeling plan for PBL class speaking behavior and build a 32-hours online PBL class speaking behavior dataset which filled the dataset blank in online PBL teaching scene;(b)Analyze video class records,use color histogram analysis and optical character recognition to extract framelevel class speaking information,and on this basis,achieve paragraph-level class speaking behavior measurement through time-dimensional identity mapping and post-processing.This program has reached a diariaztion error rate of 21.92% on the self-built online PBL dataset;(c)Analyze audio class records and train the speaker diarization pipeline which cascaded Bi-LSTM-based speech activity detection module,Bi-LSTM-based speaker change detection module and TDNN-based speaker recognition module.This class speaking behavior measurement program can work in more general scene and has reached a diariaztion error rate of 9.66% on the self-built online PBL dataset;(d)Based on the two sets of measurement programs,an audio-video joint measurement system is proposed,which can further reduce the diariaztion error rate to 7.55%.The online PBL class speaking behavior measurement system designed and implemented in this paper can solve the problem of online PBL class speaking behavior measurement.It has made a positive contribution to analyzing student psychology,discovering online PBL teaching problems,studying PBL teaching differences and improving PBL teaching quality.