1 INTRODUCTION

2 PRELIMINARY  
2.1 Problem Definition  
2.2 CSS Tasks  

3 TASK-INCREMENTAL CSS PROTOCOLS  
3.1 Datasets  
3.2 CSS Protocols  

4 METHODS  
4.1 Data-replay Methods  
4.2 Data-free Methods  
4.3 Other Routes  

5 PERFORMANCE EVALUATION AND ANALYSIS  
5.1 Evaluation Metrics  
5.2 Qualitative Comparison  
5.3 Quantitative Analysis  

6 APPLICATIONS AND PROSPECTS  
6.1 Applications  
6.2 Future Prospects  

7 CONCLUSION