In this task, you will be presented with a context from an academic paper and a question separated with a 
. You have to answer the question based on the context.
--------
Question: SIGHAN Bakeoff defines two types of evaluation settings, closed test limits all the data for learning should not be beyond the given training set, while open test does not take this limitation BIBREF21. 
 Question: What is meant by closed test setting?

Answer: closed test limits all the data for learning should not be beyond the given training set, while open test does not take this limitation


Question: The question generation model provides each candidate answer with a score by measuring semantic relevance between the question and the generated question based on the semantics of the candidate answer.  
 Question: Where is a question generation model used?

Answer: The question generation model provides each candidate answer with a score by measuring semantic relevance between the question and the generated question based on the semantics of the candidate answer. 


Question: TF-IDF (Lexical, Non-Neural) is an important unsupervised baseline. NVDM (Lexical, Neural) is a VAE-based approach for document modeling BIBREF10 . 
 Question: Which lexicon-based models did they compare with?

Answer:
TF-IDF NVDM