基于知识的问答系统不能给出最合适的答案

Question

我正在从事一个项目，这基本上是一个基于知识的问答系统。我的系统接受用户的查询，从维基百科下载相关文档，剥离所有的html标签，提取纯文本。在此之后，它将文档标记化为句子，然后形成术语-文档(TD)矩阵(查询也作为句子传递)。然后将该TD矩阵转发给概率潜在对称分析(PLSA)算法。然后，计算文档(句子)向量与查询向量之间的余弦相似度。基于与查询向量的相似度，将最相关的句子显示为答案。(词干分析也是在TD矩阵形成时完成的)。问题是is确实显示了结果，但不是最相关的。我哪里错了？我遵循的策略是否正确，或者是否存在任何其他算法可能对我有所帮助？下面我展示了我的系统返回的一些问题和答案：

What is photosynthesis?
ANSWER  1 :   The stroma contains stacks (grana) of thylakoids, which are the site of photosynthesis 

ANSWER  2 :   Factors leaf is the primary site of photosynthesis in plants 

ANSWER  3 :   Samuel Ruben and Martin Kamen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water 

ANSWER  4 :   In plants, algae and cyanobacteria, photosynthesis releases oxygen 

另一个问题

What is Artificial Intelligence?
ANSWER  1 :   the problem of creating 'artificial intelligence' will substantially be solved" 

ANSWER  2 :   37 The leading-edge definition of artificial intelligence research is changing over time 

ANSWER  3 :   Stories of these creatures and their fates discuss many of the same hopes, fears and ethical concerns that are presented by artificial intelligence 

ANSWER  4 :   History of artificial intelligence and Timeline of artificial intelligence Thinking machines and artificial beings appear in Greek myths , such as Talos of Crete , the bronze robot of Hephaestus , and Pygmalion's Galatea 13 Human likenesses believed to have intelligence were built in every major civilization 

另一个问题

Who is a hacker?

ANSWER  1 :   19 Hackers (short stories) Helba from the  

ANSWER  2 :   16 Rafael Núñez aka RaFa was a notorious most wanted hacker by the FBI since 2001 

ANSWER  3 :   Often, this type of 'white hat' hacker is called an ethical hacker 
ANSWER  4 :   Hackers also commonly use port scanners  

又一次奔跑

What is biology?
ANSWER  1 :   Molecular biology is the study of biology at a molecular level 

ANSWER  2 :   molecular biology studies the complex interactions of systems of biological molecules 

ANSWER  3 :   The similarities and differences between cell types are particularly relevant to molecular biology 

ANSWER  4 :   Contents History Foundations of modern biology 2 

Answer 1

我认为，如果你保持完全的统计方法，就很难改进你的系统。从统计NLP的角度来看，你确实做了正确的事情。现在，您可以微调一些参数。要做到这一点，你必须建立一个训练语料库，告诉系统哪个答案是正确的……然后看看参数必须取哪个值才能给出这个答案。

话虽如此，我认为微调参数不会提高你的准确率超过20% ~30%。

如果你想走得更远，你需要一种更具语义的方法，并用符号来表示知识。检查实例http://www.jfsowa.com/

Answer 2

这是一个经过充分研究的问题，称为问答(QA)。我已经在another answer中提供了一个关于QA的摘要。