For DRL using neural networks, like DQN, if there is a task that needs total different actions at similar observations, is NN going to show its weakness at this moment? Will two near input to the NN generate similar output? If so, it cannot get the different the task need?
For instance:
the agent can choose discrete action from [A,B,C,D,E], here is the observation by a set of plugs in a binary list [0,0,0,0,0,0,0].
For observation [1,1,1,1,1,1,1] and [1,1,1,1,1,1,0] they are quite similar but if the agent should conduct action A at [1,1,1,1,1,1,1] but action D at [1,1,1,1,1,1,0]. Those two observation are too closed on the distance so the DQN may not easily get the proper action? How to solve?
One more thing:
One hot encoding is a way to improve the distance between observations. It is also a common and useful way for many supervised learning tasks. But one hot will also increase the dimension heavily.
Will two near input to the NN generate similar output ?
Artificial neural networks, by nature, are non-linear function approximators. Meaning that for two given similar inputs, the output can be very different.
You might get an intuition on it considering this example, two very similar pictures (the one on the right just has some light noise added to it) give very different results for the model.
For observation [1,1,1,1,1,1,1] and [1,1,1,1,1,1,0] they are quite similar but if the agent should conduct action A at [1,1,1,1,1,1,1] but action D at [1,1,1,1,1,1,0]. Those two observation are too closed on the distance so the DQN may not easily get the proper action ?
I see no problem with this example, a properly trained NN should be able to map the desired action for both inputs. Furthermore, in your example the input vectors contain binary values, a single difference in these vectors (meaning that they have a Hamming distance of 1) is big enough for the neural net to classify them properly.
Also, the non-linearity in neural networks comes from the activation functions, hope this helps !
I want to do sentiment analysis using machine learning (text classification) approach. For example nltk Naive Bayes Classifier.
But the issue is that a small amount of my data is labeled. (For example, 100 articles are labeled positive or negative) and 500 articles are not labeled.
I was thinking that I train the classifier with labeled data and then try to predict sentiments of unlabeled data.
Is it possible?
I am a beginner in machine learning and don't know much about it.
I am using python 3.7.
Thank you in advance.
Is it possible to train the sentiment classification model with the labeled data and then use it to predict sentiment on data that is not labeled?
Yes. This is basically the definition of what supervised learning is.
I.e. you train on data that has labels, so that you can then put it into production on categorizing your data that does not have labels.
(Any book on supervised learning will have code examples.)
I wonder if your question might really be: can I use supervised learning to make a model, assign labels to another 500 articles, then do further machine learning on all 600 articles? Well the answer is still yes, but the quality will fall somewhere between these two extremes:
Assign random labels to the 500. Bad results.
Get a domain expert assign correct labels to those 500. Good results.
Your model could fall anywhere between those two extremes. It is useful to know where it is, so know if it is worth using the data. You can get an estimate of that by taking a sample, say 25 records, and have them also assigned by a domain expert. If all 25 match, there is a reasonable chance your other 475 records also have been given good labels. If e.g. only 10 of the 25 match, the model is much closer to the random end of the spectrum, and using the other 475 records is probably a bad idea.
("10", "25", etc. are arbitrary examples; choose based on the number of different labels, and your desired confidence in the results.)
I have a question. I have used transfer learning to retrain googlenet on my image classification problem. I have 80,000 images which belong to 14 categories. I set number of training steps equal to 200,000. I think the code provided by Tensorflow should have drop out implimented and it trains based on random shuffling of dataset and cross validation approach, and and I do not see any overfiting in training and classification curves, and I get high cross validation accuracy and high test accuracy but when I apply my model to new dataset then I get poor classification result. Anybodey know what is going on?Thanks!
Typically text classification, including sentiment analysis can be performed in one of 2 ways: 1. Supervised learning if there is enough training data and 2. A unsupervised training when there is no enough training data which is not prelabeled
I have only a collection of tweets which contains only the texte (reviews) and there is no polarity fir each twwet.
My question is is there any method to di sentimeent analysis on this data using unsupervised learning?
Thank you to help me
(Based on your comment, I've concentrated on the "unsupervised" part of your question, and ignored deep learning.)
If you use something like SentiWordNet you can assign a positive or negative score to each word in a tweet, and then (as the simplest approach) sum them to get a single sentiment number for each tweet.
At this point it doesn't really matter if you are doing supervised or unsupervised learning, as either way you will have a score for each tweet, and can divide them up the tweets into, say, positive, neutral and negative sentiment. What the supervised data, the class, does allow is getting an error estimate on how well it has done at classifying them.
If you want an error estimate when your training data has no classes, you could evaluate some percentage of the tweets yourself. Even just doing 30 of them will start to give you an idea of where your grouping algorithm is on the scale from random to perfect, and won't take long.
I am trying to implement a Pairwise Learning to rank model with keras where features are being computed by deep neural network.
In the pairwise L2R model, while training, I am giving the query, one positive and one negative result. And it is trained on the classification loss by difference of feature vector.
I am able to do compile and fit model successfully but the problem is to actually use this model on test data.
As in Pairwise L2R model, at testing time I would have only query and sample pair (no separate negative and positives). And I can use the calculated value before softmax to rank samples.
Is there any way I can use keras to pass data manually at test time through particular trained layers. (In short I have 3 set of inputs at train time and 2 at testing time.)