Which model should I use? - Multi label classification - keras

I am newbie on data science so my question might be basic.
I have a dataset. 1st column is comments of people about issues (as text), 2nd columns is class/labels of that failure (as text). There are many failure types on my 2nd column.
I want to train a model. When another comment is entered and explained the issue, model should classify the failure.
Can I use Keras Sequential model? Or should I use different model? If you can share a link which can be related my question, I will be appreciate.

You can use Keras Sequential model for sure. Now as a beginner, try using Dense layers, and you can also use Convolutional Neural Networks for it...
and btw try using the tensorflow.keras.preprocessing.text Tokenizer to label each word as numbers so the machine can understand.
For more information, search on Google for text classification and search for the Tokenizer.

Related

Can I fine-tune BERT using only masked language model and next sentence prediction?

So if I understand correctly there are mainly two ways to adapt BERT to a specific task: fine-tuning (all weights are changed, even pretrained ones) and feature-based (pretrained weights are frozen). However, I am confused.
When to use which one? If you have unlabeled data (unsupervised learning), should you then use fine-tuning?
If I want to fine-tuned BERT, isn't the only option to do that using masked language model and next sentence prediction? And also: is it necessary to put another layer of neural network on top?
Thank you.
Your first approach should be to try the pre-trained weights. Generally it works well. However if you are working on a different domain (e.g.: Medicine), then you'll need to fine-tune on data from new domain. Again you might be able to find pre-trained models on the domains (e.g.: BioBERT).
For adding layer, there are slightly different approaches depending on your task. E.g.: For question-answering, have a look at TANDA paper (Transfer and Adapt Pre-Trained Transformer Models for Answer Sentence Selection). It is a very nice easily readable paper which explains the transfer and adaptation strategy. Again, hugging-face has modified and pre-trained models for most of the standard tasks.

NLP Classification on a dataset

I am trying to learned NLP. I understand the basic concepts from Text Preprocessing to td-idf, and Word Embedding. How do I apply this learning? I have a Data set with two columns: Answer and Gender. I want to use NLP to transform the Answer column to vectors and then use supervised machine learning to train a model that predict where a certain type of answer was given by male or a female.
I dont know how to process after I Pre_processed the text.
You can download datasets which are available in Matlab format.
All of them are divided into train and test datasets.
check my GitHub

How to fine tune BERT on unlabeled data?

I want to fine tune BERT on a specific domain. I have texts of that domain in text files. How can I use these to fine tune BERT?
I am looking here currently.
My main objective is to get sentence embeddings using BERT.
The important distinction to make here is whether you want to fine-tune your model, or whether you want to expose it to additional pretraining.
The former is simply a way to train BERT to adapt to a specific supervised task, for which you generally need in the order of 1000 or more samples including labels.
Pretraining, on the other hand, is basically trying to help BERT better "understand" data from a certain domain, by basically continuing its unsupervised training objective ([MASK]ing specific words and trying to predict what word should be there), for which you do not need labeled data.
If your ultimate objective is sentence embeddings, however, I would strongly suggest you to have a look at Sentence Transformers, which is based on a slightly outdated version of Huggingface's transformers library, but primarily tries to generate high-quality embeddings. Note that there are ways to train with surrogate losses, where you try to emulate some form ofloss that is relevant for embeddings.
Edit: The author of Sentence-Transformers recently joined Huggingface, so I expect support to greatly improve over the upcoming months!
#dennlinger gave an exhaustive answer. Additional pretraining is also referred as "post-training", "domain adaptation" and "language modeling fine-tuning". here you will find an example how to do it.
But, since you want to have good sentence embeddings, you better use Sentence Transformers. Moreover, they provide fine-tuned models, which already capable of understanding semantic similarity between sentences. "Continue Training on Other Data" section is what you want to further fine-tune the model on your domain. You do have to prepare training dataset, according to one of available loss functions. E.g. ContrastLoss requires a pair of texts and a label, whether this pair is similar.
I believe transfer learning is useful to train the model on a specific domain. First you load the pretrained base model and freeze its weights, then you add another layer on top of the base model and train that layer based on your own training data. However, the data would need to be labelled.
Tensorflow has some useful guide on transfer learning.
You are talking about pre-training. Fine-tuning on unlabeled data is called pre-training and for getting started, you can take a look over here.

Creating input data for BERT modelling - multiclass text classification

I'm trying to build a keras model to classify text for 45 different classes. I'm a little confused about preparing my data for the input as required by google's BERT model.
Some blog posts insert data as a tf dataset with input_ids, segment ids, and mask ids, as in this guide, but then some only go with input_ids and masks, as in this guide.
Also in the second guide, it notes that the segment mask and attention mask inputs are optional.
Can anyone explain whether or not those two are required for a multiclass classification task?
If it helps, each row of my data can consist of any number of sentences within a reasonably sized paragraph. I want to be able to classify each paragraph/input to a single label.
I can't seem to find many guides/blogs about using BERT with Keras (Tensorflow 2) for a multiclass problem, indeed many of them are for multi-label problems.
I guess it is too late to answer but I had the same question. I went through huggingface code and found that if attention_mask and segment_type ids are None then by default it pays attention to all tokens and all the segments are given id 0.
If you want to check it out, you can find the code here
Let me know if this clarifies it or you think otherwise.

Is there any way to classify text based on some given keywords using python?

i been trying to learn a bit of machine learning for a project that I'm working in. At the moment I managed to classify text using SVM with sklearn and spacy having some good results, but i want to not only classify the text with svm, I also want it to be classified based on a list of keywords that I have. For example: If the sentence has the word fast or seconds I would like it to be classified as performance.
I'm really new to machine learning and I would really appreciate any advice.
I assume that you are already taking a portion of your data, classifying it manually and then using the result as your training data for the SVM algorithm.
If yes, then you could just append your list of keywords (features) and desired classifications (labels) to your training data. If you are not doing it already, I'd recommend using the SnowballStemmer on your training data features.

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