Are there any tools that analyze the meaning of given sentences? Recommendations are greatly appreciated.
Thanks in advance!
I am also looking for similar tools. One thing I found recently was this sentiment analysis tool built by researchers at Stanford.
It provides a model of analyzing the sentiment of a given sentence. It's interesting and even this seemingly simple idea is quite involved to model in an accurate way. It utilizes machine learning to develop higher accuracy as well. There is a live demo where you can input sentences to analyze.
http://nlp.stanford.edu/sentiment/
I also saw this RelEx semantic dependency relationship extractor.
http://wiki.opencog.org/w/Sentence_algorithms
Some natural language understanding tools can analyze the meaning of sentences, including NLTK and Attempto Controlled English. There are several implementations of discourse representation structures and semantic parsers with a similar purpose.
There are also several parsers that can be used to generate a meaning representation from the text that is being parsed.
Related
My work is planning on using a UIMA cluster to run documents through to extract named entities and what not. As I understand it, UIMA have very few NLP components packaged with it. I've been testing GATE for awhile now and am fairly comfortable with it. It does ok on normal text, but when we run it through some representative test data, the accuracy drops way down. The text data we have internally is sometimes all caps, sometimes all lowercase, or a mix of the two in the same document. Even using ANNIE's all caps rules, the accuracy still leaves much to be desired. I've recently heard of Stanford NLP and OpenNLP but haven't had time to extensively train and test them. How do those two compare in terms of accuracy with ANNIE? Do they work with UIMA like GATE does?
Thanks in advance.
It's not possible/reasonable to give a general estimate on performance of these systems. As you said, on your test data the accuracy declines. That's for several reasons, one is the language characteristics of your documents, another is characteristics of the annotations you are expecting to see. Afaik for every NER task there are similar but still different annotation guidelines.
Having that said, on your questions:
ANNIE is the only free open source rule-based NER system in Java I could find. It's written for news articles and I guess tuned for the MUC 6 task. It's good for proof of concepts, but getting a bit outdated. Main advantage is that you can start improving it without any knowledge in machine learning, nlp, well maybe a little java. Just study JAPE and give it a shot.
OpenNLP, Stanford NLP, etc. come by default with models for news articles and perform (just looking at results, never tested them on a big corpus) better than ANNIE. I liked the Stanford parser better than OpenNLP, again just looking at documents, mostly news articles.
Without knowing what your documents look like I really can't say much more. You should decide if your data is suitable for rules or you go the machine learning way and use OpenNLP or Stanford parser or Illinois tagger or anything. The Stanford parser seems more appropriate for just pouring your data, training and producing results, while OpenNLP seems more appropriate for trying different algorithms, playing with parameters, etc.
For your GATE over UIMA dispute, I tried both and found more viral community and better documentation for GATE. Sorry for giving personal opinions :)
Just for the record answering the UIMA angle: For both Stanford NLP and OpenNLP, there is excellent packaging as UIMA analysis engines available via the DKPro Core project.
I would like to add one more note. UIMA and GATE are two frameworks for the creation of Natural Language Processing(NLP) applications. However, Name Entity Recognition (NER) is a basic NLP component and you can find an implementation of NER, independent of UIMA and GATE. The good news is you can usually find a wrapper for a decent NER in the UIMA and GATE. To make it clear let see this example:
OpenNLP NER
A wrapper for OpenNLP NER in GATE
A wrapper for OpenNLP NER in UIMA
It is the same for the Stanford NER component.
Coming back to your question, this website lists the state of the art NERs:
http://www.aclweb.org/aclwiki/index.php?title=Named_Entity_Recognition_(State_of_the_art)
For example, in the MUC-7 competition, best participant named LTG got the result with the accuracy of 93.39%.
http://www.aclweb.org/aclwiki/index.php?title=MUC-7_(State_of_the_art)
Note that if you want to use such a state of are implementation, you may have some issue with their license.
Can anyone show a simple implementation or usage example of a tf-idf algorithm in Smalltalk for natural language processing?
I've found an implementation in a package called NaturalSmalltalk, but it seems too complicated for my needs. A simple implementation in Python is like this one.
I've noticed there is another tf-idf in Hapax, but it seems related to analysis of software systems vocabularies, and I didn't found examples of how to use it.
I am the author of the original Hapax package for Visualworks. Hapax is a general purpose information retrieval package, it should be able to work with any kind of text files. I just happens so that I used to use it to analyze source code files.
The class that you are looking for is TermDocumentMatrix, there should be two methods globalWeighting: and localWeighting: to which you pass instances of InverseDocumentFrequency and either LogTermFrequency or TermFrequency depending on your needs. Typically when referring to tfidf people mean it to include logarithmic term frequencies.
There should best tests demonstrating the TDM class using a small example corpus. If the tests have not been ported to Squeak, please let me know so I can provide you with an example.
TextLint is a system based on PetitParser to parse and match patterns in natural language. It doens't provide what you ask for, but it shouldn't be too difficult to extend the model to compute word frequencies.
Which tools would you recommend to look into for semantic analysis of text?
Here is my problem: I have a corpus of words (keywords, tags).
I need to process sentences, input by users and find if they are semantically close to words in the corpus that I have.
Any kind of suggestions (books or actual toolkits / APIs) are very welcome.
Regards,
Some useful links to begin with:
http://alias-i.com/lingpipe/demos/tutorial/sentiment/read-me.html
http://kmandcomputing.blogspot.com/2008/06/opinion-mining-with-rapidminer-quick.html
http://rapid-i.com/content/blogcategory/38/69/
http://www.cs.cornell.edu/People/pabo/movie-review-data/otherexperiments.html
http://wordnet.princeton.edu/
Tools/Libraries:
Open NLP
lingpipe
If you consider your corpus as an ontology, Apache Stanbol - http://incubator.apache.org/stanbol/ - might be useful. It uses dbpedia as the default ontology while analyzing text. Although it is incubating, enhancer component is good enough foe adoption. So, you can give it a try.
You can try some WordNet similarity measurements. Ted Pedersen has a compilation of those metrics in WordNet::Similarity which you can experiment and look into. There are counterpart implementations in other languages (e.g. Java).
I have started working on a project which requires Natural Language Processing. We have do the spell checking as well as mapping sentences to phrases and their synonyms. I first thought of using GATE but i am confused on what to use? I found an interesting post here which got me even more confused.
http://lordpimpington.com/codespeaks/drupal-5.1/?q=node/5
Please help me decide on what suits my purpose the best. I am working a web application which will us this NLP tool as a service.
You didn't really give much info, but try this: http://www.nltk.org/
I don't think NLTK does spell checking (I could be wrong on this), but it can do parts of speech tagging for text input.
For finding/matching synonyms you could use something like WordNet http://wordnet.princeton.edu/
If you're doing something really domain specific: I would recommend coming up with your own ontology for domain specific terms.
If you are using Python you can develop a spell checker with Python Enchant.
NLTK is good for developing Sentiment Analysis system too. I have some prototypes of the same too
Jaggu
If you are using deep learning based models, and if you have sufficient data, you can implement task specific models for any purpose. With the development of deep leaning based languages models, you can used word embedding based models with lexicon resources to obtain synonyms and antonyms. You can also follow the links below to obtain more resources.
https://stanfordnlp.github.io/CoreNLP/
https://www.nltk.org/
https://wordnet.princeton.edu/
I need your help in determining the best approach for analyzing industry-specific sentences (i.e. movie reviews) for "positive" vs "negative". I've seen libraries such as OpenNLP before, but it's too low-level - it just gives me the basic sentence composition; what I need is a higher-level structure:
- hopefully with wordlists
- hopefully trainable on my set of data
Thanks!
What you are looking for is commonly dubbed Sentiment Analysis. Typically, sentiment analysis is not able to handle delicate subtleties, like sarcasm or irony, but it fares pretty well if you throw a large set of data at it.
Sentiment analysis usually needs quite a bit of pre-processing. At least tokenization, sentence boundary detection and part-of-speech tagging. Sometimes, syntactic parsing can be important. Doing it properly is an entire branch of research in computational linguistics, and I wouldn't advise you with coming up with your own solution unless you take your time to study the field first.
OpenNLP has some tools to aid sentiment analysis, but if you want something more serious, you should look into the LingPipe toolkit. It has some built-in SA-functionality and a nice tutorial. And you can train it on your own set of data, but don't think that it is entirely trivial :-).
Googling for the term will probably also give you some resources to work with. If you have any more specific question, just ask, I'm watching the nlp-tag closely ;-)
Some approaches to sentiment analysis use strategies popular on other text classification tasks. The most common being transforming your film review into a word vector, and feeding it into a classifier algorithm as training data. Most popular data mining packages can help you here. You could have a look at this tutorial on sentiment classification illustrating how to do an experiment using the open source RapidMiner toolkit.
Incidentally, there is a good data set made available for research purposes related to detecting opinion on film reviews. It is based on IMDB user reviews, and you can check many related research work on the area and how they use the data set.
Its worth bearing in mind that the effectiveness of these methods can only be judged from a statistical viewpoint, so you can pretty much assume there will be misclassifications and cases where opinion is hard to detect. As already noticed in this thread, detecting things like irony and sarcasm can be very difficult indeed.