Does Named Entity Recognition only work on nouns? - spacy

I am considering training spaCy to recognize a custom named entity, but I am curious if this really only works for nouns or if it would equally work well with POS such as adjectives?
For example, I want to train on words like depressed, anxious, paranoid, etc. I'm trying to curate a list of adjectives that are considered clinically relevant, separating them from other irrelevant adjectives like happy, sad, unwell.
Is NER the right approach here, would it make more sense to just manually maintain a list of clinical adjectives and use a custom extension (e.g. ent._.clinical_adj) to mark them?

NER is typically used mainly on nouns. It's not that sensitive to part of speech type, but picking up just adjectives would be an unusual use.
Since it sounds like you do have a specific, finite list of words you're interested in, it probably makes sense for you to just use that word list and an extension to mark them.
You might also want to look at the DependencyMatcher. If there are some nouns you are interested in, you can use the DependencyMatcher to get all adjectives that modify them, for example.

Related

Is it conventional to use verbs to describe relationships between classes in UML?

I've come across resources that depict UML diagrams with verbs like 'wrote' to describe how one class uses another. Does this convention exist in UML; is it overkill to add this convention to my designs?
ex:
Yes, this is a common convention: the name over the association (Wrote) is the name of the association. You may add the solid triangle to show the order of reading.
But often the associations are shown without name, or without the triangle, if this information is not important for the understanding of the diagram. Adding this systematically in the diagram might make it more difficult to read and give a feeling of information overload. So, up to you to find the right balance in your specific case.
Just trying to summarize a few experiences:
Using the name/triangle notation is often advantageous when working with business stakeholders. In that case the triangle is mandatory because without it can lead to confusion. Not so in the above example but it should be a modeling rule set in the domain.
Applying roles/multiplicities is practical when moving over to technical aspects. In that stage the label is not important any more as it can be guessed from the role names. So the best is to have diagrams for business people having just the labels/triangles and ones for techies containing roles/multiplicities.
If for any case you want both notations make sure that you have enough space to distinguish between labels and role names. That makes dense diagrams impossible.
Like in a Chinese Restaurant: if there's all you can eat please listen to your stomach.

SpaCy different Language Models

I'm making some progress:) developing my litle OCR Project.
I was wondering if my idea is possible in this case!
After extracting the Text from a Images (ocr), I use nlp (spacy) to identify two Entities (LOCation and PERson). I write to a Dictionary and later in a JSON Data. That works good.
Now I'm wondering if I can improve my identified Entities.
One way I can imagine is to use the right Language Model for the text.
I have varies Texts in German, English,Spanish and French.
At the moment I'm using the
But now I have no idea how to put langdetect into this
Have a great week!
Greets
Here is a link that you might find useful when it comes to detecting a language (There are multiple options including langdetect) - How to detect language
You can create a dictionary with the languages you plan to detect and match it with langdetect's output. I guess you have the rest sorted out.

Custom model in Apache Open NLP

I am working currently with custom models which I am training for my own use case. My use case is to classify emails based on whether it is an address change request. If the address change request could be understood from a single sentence, it is working fine without issues. But if the address change request needs to be understood from multiple sentences, it is not working.
Giving few examples below :-
Example 1 :- THIS IS WORKING
1.
a)training file :-
Guys I wish to <START:contactupdate> change my address <END> .
My new address is 68 Dorset Road, Coventry, West Midlands, CV1 4ED.
Please confirm once you are done.
Thanks.
b)Testing model with the below sentence :-
String input = "Guys I wish to change my address.My new address is 68 Dorset Road, Coventry, West Midlands, CV1 4ED.Please confirm once you are done. Thanks."; //Working
EXAMPLE 2 :- This is not working.
Lets say the address change request can only be deduced from multiple lines.
"My old address is no longer valid. Need to update it."
How do I train my model in this scenario?How do I specify the custom tags for above?
Can you please help. I am stuck.
Many Thanks
What do you mean with not working? That the thing you want to retrieve is not retrieved? Or that the training crashes somewhere when the tags are spread out over multiple lines?
In general, the (by default MaxEnt) model that you are training in this procedure tries to detect common features for the thing you are training for. Typically, these are named entities like persons, organisations, locations. And in many languages, these contain typical features (like the prefix Mr./Mrs., the suffix corp., the morpheme "street", respectively). This can be picked up by the model, and applied in new data, leading to the recognition of whichever it is you want to recognise. The thing you are trying to do however, is pretty advanced NLP already. Since the longer the phrase, the larger the possible variation, it becomes more difficult to pick up commonalities. I'd say for your use case, people are typically using parsing (either constituency or dependency parsing) or other more sophisticated tools than just this relatively flat pattern recognition. So you may want to look into these instead. I don't know how much data you have at your disposal, from which you can infer different ways of expressing the desire to change an address in a customer database. If reasonable (i.e. not just a couple of sentences), you may want to manually annotate them, parse the corpus, use machine learning on the parse trees/graphs for the sentences of interest and go about it in this way. As mentioned, quite advanced NLP in my opinion, and not something that has an out of the box solution.
If I understand your question correctly, I think you are trying to categorize emails to find out if its for address change. But the model example looks like for named entity. In my opinion, it might be better to use "Document Categorizer" feature of Apache OpenNLP.
You can provide different samples for possible sentences which can be categorized as address change. "Address_change", "general_inquiry" etc. can be a categories. This way you can add as many different sampels as you want with many variations of sentences. Here is easy & basic tutorial for document categorization training & usage.

Lucene to bring cheeseburger when searching for burger

I would like that if a lucene document contains the word cheeseburger and a user searches for burger for this documents to come up. I see that I will probably need a custom analyzer to break this compound word into cheese and burger. However, breaking words may also bring irrelevant results.
Ex: if when indexing production we index product and ion as well, then when the user searches for ion documents containing production will come out, which is not relevant.
So a simple word breaker won't cut it. I need a way of knowing that cheeseburger is associated to burger and cheese, but that production is not associated to ion.
Is there a more intelligent process to achieve this?
Does this has a name just like stemming is to reduce words to their root form?
Depending on how accurate you want your synonymy to be, you might need to look into approaches such as Latent Semantic Analysis (LSA) and its variants such as LDA etc. A simpler approach would be to use an Ontology such as Wordnet to augment your searches. A wordnet Lucene index is available. However if your scenario includes domain-specific vocab then you might need to generate a "mapping" Ontology.
You should look at DictionaryCompoundWordTokenFilter which uses a brute-force algorithm to split compound nouns based on a dictionary.
in most cases you can simply use wildcard queries with a leading wildcard *burger. You only have to enable the support for leading wildcards on your query parser:
parser = new QueryParser(LuceneVersion.getVersion(), searchedAttributes, analyzer);
parser.setAllowLeadingWildcard(true);
Take care:
Leading wildcards might slow your search down.
If you need a more specific solution I would suggest to go with stemming. If really a matter of finding the right analyzer.
There are stemming implementations for several languages e.g. the SnowballAnalyzer (http://lucene.apache.org/core/3_6_0/api/all/org/apache/lucene/analysis/snowball/SnowballAnalyzer.html).
Best regards,
Chris
Getting associations by looking at the word is not going to scale to other words. For example, you cannot know "whopper" is associated with burger and "big-mac" is associated with cheese just by looking at the words. To make the search aware of the associations, you probably need a database of associations like "A is a B" or "A contains B". (As Mikos has mentioned, I think WordNet provides such a database.) Then, when you see B in a query, you translate the query so that it also searches for A.
I think the underlying question is -- how big is the collection you are indexing? If you are indexing some collection where all of the synonyms and related words are already known, then the index can just include the synonyms and related words directly, like 'cheeseburger' including the related words 'cheese' and 'burger'. (An approach successfully used in the LOINC standard medical terms Lucene index.)
If you are trying to solve the general problem for a whole human language (English, Chinese, etc.) then you have to move to some kind of semantic analysis as mentioned above.
It might be useful to talk with the subject matter experts of the area you are indexing to see how they search for terms -- what synonyms/related words do they use, do they have defined lists of synonyms/related words, do they need/use stemming, etc. This should give you some idea as to which approach (direct synonym/related-word inclusion or semantic analysis) you need to pursue.

What are the things should we consider while writing a Spell Checker?

I want to write a very simple Spell Checker. The spell checker will try to match the input word with equivalent words form the dictionary.
What can be done to find those 'equivalent words'? What analysis can be preformed on two words to mark them equivalent?
Before investing too much trying to unravel that i'd first look to already existing implementations like Aspell or netspell for two main reasons
Not much point in re-inventing the wheel. Spell checking is much trickier than it first appears and it makes sense to build on work that has already been done
If your interest is finding out how to do it, the source code and community will be a great benefit should you decide to implement your own anyway
Much depends on your use case. For example:
Is your dictionary very small (about twenty words)? In this case it probably is better to precompute all possible nearby mistaken words and use a table/hash lookup.
What is your error model? Aspell has at least two (one for spelling errors caused by nearby letters on the keyboard, and the other for spelling errors caused by the way a word sounds).
How dynamic is your dictionary? Can you afford to do a massive preparation in order to get an efficient retrieval?
You may need a "word equivalence" measure like Double Metaphone, in addition to edit distance.
You can get some feel by reading Peter Norvig's great description of spelling correction.
And, of course, whenever possible, steal code. Do not reinvent the wheel without a reason - a reason could be a very special domain, a special way your users make spelling mistakes, or just to learn how it's done.
Edit Distance is the theory you need to write a spell checker. You also need a dictionary. Most UNIX systems come with a dictionary already installed for your locale.
I just finished implementing a spell checker and used a combination of the following in getting a list of "suggested" words
Phonetic hashing of the "misspelled" word to lookup a hash of identical dictionary hashed real words (for java check out Apache Commons Codec for a suitable library). The phonetic hash of your dictionary file can be precomputed.
Edit distance between the input and the potentials (this is reasonably expensive so you need to reduce the list first with something like a phonetic hash, assuming a higher volume load - in my case, a server based spell check)
A known list of common misspellings, e.g. recieve vs. receive.
An ordered list of the most common words in the english language
Essentially I weighted each potential word primarily based on edit-distance and commonality. e.g. if word probability is a percentage, then
weight = edit-distance * 100 / probability
(lower weights are better)
But then I also also override any result with the known common misspellings (i.e. these always float to the top suggested result).
There may be better ways, but this worked pretty well.
You may also wish to ignore ALL CAPS words, initials etc, so choosing what to ignore is also something to think about.
Under linux/unix you have ispell. Why reinventing the whell.