I need some advice on the following problem.
I'm given a set of weighted keywords (by percentage) and need to find a text in a database that best matches those keywords. I will give an example.
I'm presented with these keywords
Sun(90%)
National Park(85% some keywords contain 2 words)
Landmark(60%)
Now lets say my database contains 3 entries of texts e.g
Going-to-the-Sun Road is a scenic mountain road in the Rocky Mountains of the western United States, in Glacier National Park in Montana.
Everybody has a little bit of the sun and moon in them. Everybody has a little bit of man, woman, and animal in them.
A hybrid car is one that uses more than one means of propulsion - that means combining a petrol or diesel engine with an electric motor.
Obviously the first text is the one that best describes the given set of keywords so this is what I want to recommend to the user. Following the second text that somewhat relates with the "sun" keyword and that could be an acceptable choice too.
The 3rd text is totally irrelevant and shall only be recommended as a last resort when everything else fails.
I'm totally new to that kind of stuff so I need some advice as to which technologies/algorithms I should use. Seems like there is some machine learning (nlp) involved or some kind of fuzzy logic. I'm not really sure.
You need to use a combination of query terms boosting and synonyms
Look into Is there a way to do fuzzy string matching for words on string?
Related
My Motivations I'm trying to learn German and realized there's a confounding fact with the structure of German: every noun has a gender which seems unrelated to the noun itself in many cases.
Unlike languages such as English, each noun has a different definite article, depending on gender: der (masculine), die (feminine), and das (neuter). For example:
das Mädchen ("the girl"), der Rock ("the skirt), die Hose ("the trousers/pants"). So, there seems to be no correlation between gender assignment of nouns and their meanings.
The Data
I gathered up to 5000 German words with 3 columns (das, der, die) for each word with 1's and 0's. So, my data is already clustered with one hot encoding and I'm not trying to predict anything.
Why I'm here I am clueless on where to start, how to approach this problem as the concept of distance in clustering doesn't make sense to me in this setting. I can't think of a way to generate an understandable description of these clusters. The mixed data makes it impossible for me to think of some hard-coded metrics for evaluation.
So, my question is:
I want to find some patterns, some characteristics of these words that made them fall in a specific cluster. I don't know if I'm making any sense but some people managed to find some patterns already (for example word endings, elongated long objects tend to be masculine etc., etc) and I believe ML/AI could do a way better job at this. Would it be possible for me to do something like this?
Some personal thoughts
While I was doing some research (perhaps, naive), I realized the potential options are decision trees and cobweb algorithms. Also, I was thinking if I could just scrape a few images (say 5) for every word and try to run some image classification and see the intermediate NN's to see if any specific shapes support a specific object gender. In addition to that, I was wondering whether scraping the data of google n-gram viewers of these words could help in anyway. I couldn't think of a way to use NLP or its sub domains.
Alternatives If everything I just wrote sounds nonsensical, please suggest me a way to make visual representations of my dataframe (more like nodes and paths with images at nodes, one for each cluster) in Python so that I could make pictorial mind maps and try to by heart them.
The ultimate purpose is to make learning German simpler for myself and possibly for others
So I am working on a artist classification project that utilizes hip hop lyrics from genius.com. The problem is these lyrics are user generated, so the same word can be spelled in various different ways, especially if it is slang which is a very common case in hip hop.
I looked into spell correction using hunspell/pyhunspell, but the problem with that is it doesn't fix slang misspellings. I technically could make a mini dictionary with a bunch of misspelled variations but that is effectively useless because there could be a dozen variations of the same word over my (growing) 6000 song corpus.
Any suggestions?
You could try to stem your words. More information on stemming here. This would help grouping together words with close spelling variations.
A popular stemming scheme is the Porter Stemmer, which implementation can be found in most NLP packages, eg. NLTK
I would discard, if possible, short words, or contracted words which somehow are too hard to automatically correct them (conditioned on checking that it won't affect your final result).
For longer words, you may want to use metrics like Levenshtein distance or Jaro similarity. The first one consists of the minimum number of additions, deletes or replaces to convert one candidate word into another. The second one, provides a similar result, between 0 and 1, and putting more emphasis in the last characters of a word.
If you have access to the correct version of your slang word, you could convert the closest candidates to the correct one. Of course, trying not to apply it to different correct words.
If you're working with Python, here some implementations are provided.
I am working on developing a tool for language identification of a given text i.e. given a sample text, identify the language (for e.g. English, Swedish, German, etc.) it is written in.
Now the strategy I have decided to follow (based on a few references I have gathered) are as follows -
a) Create a character n-gram model (The value of n is decided based on certain heuristics and computations)
b) Use a machine learning classifier(such as naive bayes) to predict the language of the given text.
Now, the doubt I have is - Is creating a character N-gram model necessary. As in, what disadvantage does a simple bag of words strategy have i.e. if I use all the words possible in the respective language to create a prediction model, what could be the possible cases where it would fail.
The reason why this doubt arose was the fact that any reference document/research paper I've come across states that language identification is a very difficult task. However, just using this strategy of using the words in the language seems to be a simple task.
EDIT: One reason why N-gram should be preferred is to make the model robust even if there are typos as stated here. Can anyone point out more?
if I use all the words possible in the respective language to create a prediction model, what could be the possible cases where it would fail
Pretty much the same cases were a character n-gram model would fail. The problem is that you're not going to find appropriate statistics for all possible words.(*) Character n-gram statistics are easier to accumulate and more robust, even for text without typos: words in a language tend to follow the same spelling patterns. E.g. had you not found statistics for the Dutch word "uitbuiken" (a pretty rare word), then the occurrence of the n-grams "uit", "bui" and "uik" would still be strong indicators of this being Dutch.
(*) In agglutinative languages such as Turkish, new words can be formed by stringing morphemes together and the number of possible words is immense. Check the first few chapters of Jurafsky and Martin, or any undergraduate linguistics text, for interesting discussions on the possible number of words per language.
Cavnar and Trenkle proposed a very simple yet efficient approach using character n-grams of variable length. Maybe you should try to implement it first and move to a more complex ML approach if C&T approach doesn't meet your requirements.
Basically, the idea is to build a language model using only the X (e.g. X = 300) most frequent n-grams of variable length (e.g. 1 <= N <= 5). Doing so, you are very likely to capture most functional words/morphemes of the considered language... without any prior linguistic knowledge on that language!
Why would you choose character n-grams over a BoW approach? I think the notion of character n-gram is pretty straightforward and apply to every written language. Word, is a much much complex notion which greatly differ from one language to another (consider languages with almost no spacing marks).
Reference: http://odur.let.rug.nl/~vannoord/TextCat/textcat.pdf
The performance really depends on your expected input. If you will be classifying multi-paragraph text all in one language, a functional words list (which your "bag of words" with pruning of hapaxes will quickly approximate) might well serve you perfectly, and could work better than n-grams.
There is significant overlap between individual words -- "of" could be Dutch or English; "and" is very common in English but also means "duck" in the Scandinavian languages, etc. But given enough input data, overlaps for individual stop words will not confuse your algorithm very often.
My anecdotal evidence is from using libtextcat on the Reuters multilingual newswire corpus. Many of the telegrams contain a lot of proper names, loan words etc. which throw off the n-gram classifier a lot of the time; whereas just examining the stop words would (in my humble estimation) produce much more stable results.
On the other hand, if you need to identify short, telegraphic utterances which might not be in your dictionary, a dictionary-based approach is obviously flawed. Note that many North European languages have very productive word formation by free compounding -- you see words like "tandborstställbrist" and "yhdyssanatauti" being coined left and right (and Finnish has agglutination on top -- "yhdyssanataudittomienkinkohan") which simply cannot be expected to be in a dictionary until somebody decides to use them.
Summary
I am trying to design a heuristic for matching up sentences in a translation (from the original language to the translated language) and would like guidance and tips. Perhaps there is a heuristic that already does something similar? So given two text files, I would like to be able to match up the sentences (so I can pick out a sentence and say this is the translation of that sentence).
Details
The input text would be translated novels. So I do not expect the translations to be literal, although, using something like google translate might be a good way to test the accuracy of the heuristic.
To help me, I have a library that will gloss the contents of the translated text and give me the definitions of the words in the sentence. Other things I know:
Chapters and order are preserved; I know that the first sentence in chapter three will match with the first sentence in chapter three of the translation (Note, this is not strictly true; the first sentence might match up with the first two sentences, or even the second sentence)
I can calculate the overall size (characters, sentences, paragraphs); which could give me an idea of the average difference in sentence size (for example, the translation might be 30% longer).
Looking at the some books I have, the translated version has about 30% more sentences than the original text.
Implementation
(if it matters)
I am planning to do this in Java - but I am not that fussed - any language will do.
I am not greatly concerned about speed.
I guess to to be sure of the matches, some user feedback might be required. Like saying "Yes, this sentence definitely matches with that sentence." This would give the heuristic some more ground to stand on. This would mean that the user would need a little proficiency in the languages.
Background
(for those interested)
The reason I want to make this is that I want it to assist with my foreign language study. I am studying Japanese and find it hard to find "good" material (where "good" is defined by what I like). There are already tools to do something similar with subtitles from videos (an easier task - using the timing information of the video). But nothing, as far as I know, for texts.
There are tools called "sentence aligners" used in NLP research that does exactly what you want.
I advise hunalign:
http://mokk.bme.hu/resources/hunalign/
and MS sentence aligner:
http://research.microsoft.com/en-us/downloads/aafd5dcf-4dcc-49b2-8a22-f7055113e656/
Both are quite OK, but remember that nothing is perfect. Sentences that are too hard to be aligned will be dropped and some sentences may be wrongly aligned.
I am looking for a method to build a hierarchy of words.
Background: I am a "amateur" natural language processing enthusiast and right now one of the problems that I am interested in is determining the hierarchy of word semantics from a group of words.
For example, if I have the set which contains a "super" representation of others, i.e.
[cat, dog, monkey, animal, bird, ... ]
I am interested to use any technique which would allow me to extract the word 'animal' which has the most meaningful and accurate representation of the other words inside this set.
Note: they are NOT the same in meaning. cat != dog != monkey != animal
BUT cat is a subset of animal and dog is a subset of animal.
I know by now a lot of you will be telling me to use wordnet. Well, I will try to but I am actually interested in doing a very domain specific area which WordNet doesn't apply because:
1) Most words are not found in Wordnet
2) All the words are in another language; translation is possible but is to limited effect.
another example would be:
[ noise reduction, focal length, flash, functionality, .. ]
so functionality includes everything in this set.
I have also tried crawling wikipedia pages and applying some techniques on td-idf etc but wikipedia pages doesn't really do much either.
Can someone possibly enlighten me as to what direction my research should go towards? (I could use anything)
It looks like you want to use something like the hypernym/hyponym relationships in WordNet, but without actually using WordNet due to language and domain specific coverage issues? That is, if you had the domain specific hypernym relationships, you could get the "super" representation by just looking for the nearest parent that subsumed all of the words in the list, or the nearest node that was equal to one of the list words and subsumed all of the others.
To start, I would first point out that WordNets are actually available for many of the worlds major languages see the list at Global WordNet.
To get domain specific hypernym relationships, you could use the technique presented in Snow et al.'s Learning syntactic patterns for automatic hypernym discovery. That is, you could start off with a small list of seed hypernyms, and then use them to train a classifier to detected the hypernyms in a corpus. You would then run this classifier over data from your domain in order to build a list of domain specific hypernym pairs.
The opinion mining and sentiment analysis folks might be doing related things, in terms of deciding what words represent features of products, without knowing anything about the products.
A quick sketch of an idea for how you might do this, which I've totally made up on the spot:
Parse a bunch of sentences in the relevant domain; find the noun phrases and adjectives. Figure out which noun phrases are associated with which adjectives. Cluster the noun phrases together based on the set of adjectives used to describe them. Animals will tend together because they're going to be described by adjectives like "furry" or "cute", etc. (In particular, hierarchical clustering would probably be most appropriate.)
If you try this, and it works, let me know. :)