3.1 ANSWER IDENTIFICATION SYSTEM [12], WHICH WAS DESIGNED IN 19...

2.3.1 Answer Identification

system [12], which was designed in 1971 as a result of the The answer type which was determined during question Apollo moon mission, to enable lunar geologists to processing is crucial to the identification of the answer. Since conveniently access, compare and evaluate the chemical usually the answer type is not explicit in the question or the analysis data on lunar rock and soil composition that was answer, it is necessary to rely on a parser to recognize named accumulating. Many other early QA systems such as entities (e.g. names of persons and organizations, monetary SYNTHEX, LIFER, and PLANES [13] aimed to achieve the units, dates, etc.). Also, using a part-of-speech tagger (e.g., same objective of getting an answer for a question asked in Brill tagger) can help to enable recognition of answer natural language. candidates within identified paragraphs. The recognition of However, QA systems have developed over the past few the answer type returned by the parser creates a candidate decades until they reached the structure that we have answer. The extraction of the answer and its validation are nowadays. QA systems, as mentioned before, have a based on a set of heuristics [8]. backbone composed of three main parts: question classification, information retrieval, and answer extraction.