Using prefix tree as an input in a neural network - deep-learning

So I am working on a project and I need to analyse a prefix tree. I was wondering if I can train an MLAI to do so for me, but now I'm stuck on figuring out how to pass a tree as input. The tree can have an arbitrary number of nodes, and the data in each node maybe be a string or some other type. It is also possible that I would need to pass more than just 1 tree as input. I wanna know if what I'm aiming for is even possible or not.

There are varied neural networks that can accept size-varied structured data as inputs, however this is not as simple as taking off the shelf MLP. At the time of writing this answer the most standard set of architectures would be Graph Neural Networks (since trees are just specific graphs).

Related

Stacking/chaining CNNs for different use cases

So I'm getting more and more into deep learning using CNNs.
I was wondering if there are examples of "chained" (I don't know what the correct term would be) CNNs - what I mean by that is, using e.g. a first CNN to perform a semantic segmentation task while using its output as input for a second CNN which for example performs a classification task.
My questions would be:
What is the correct term for this sequential use of neural networks?
Is there a way to pack multiple networks into one "big" network which can be trained in one a single step instead of training 2 models and combining them.
Also if anyone could maybe provide a link so I could read about that kind of stuff, I'd really appreciate it.
Thanks a lot in advance!
Sequential use of independent neural networks can have different interpretations:
The first model may be viewed as a feature extractor and the second one is a classifier.
It may be viewed as a special case of stacking (stacked generalization) with a single model on the first level.
It is a common practice in deep learning to chain multiple models together and train them jointly. Usually it calls end-to-end learning. Please see the answer about it: https://ai.stackexchange.com/questions/16575/what-does-end-to-end-training-mean

Creating a dataset of images for object detection for extremely specific task

Even though I am quite familiar with the concepts of Machine Learning & Deep Learning, I never needed to create my own dataset before.
Now, for my thesis, I have to create my own dataset with images of an object that there are no datasets available on the internet(just assume that this is ground-truth).
I have limited computational power so I want to use YOLO, SSD or efficientdet.
Do I need to go over every single image I have in my dataset by my human eyes and create bounding box center coordinates and dimensions to log them with their labels?
Thanks
Yes, you will need to do that.
At the same time, though the task is niche, you could benefit from the concept of transfer learning. That is, you can use a pre-trained backbone in order to help your model to learn faster/achieve better results/need fewer annotations example, but you will still need to annotate the new dataset on your own.
You can use software such as LabelBox, as a starting point, it is very good since it allows you to output the format in Pascal(VOC) format, YOLO and COCO format, so it is a matter of choice/what is more suitable for you.

What does backbone mean in a neural network?

I am getting confused with the meaning of "backbone" in neural networks, especially in the DeepLabv3+ paper. I did some research and found out that backbone could mean
the feature extraction part of a network
DeepLabv3+ took Xception and ResNet-101 as its backbone. However, I am not familiar with the entire structure of DeepLabv3+, which part the backbone refers to, and which parts remain the same?
A generalized description or definition of backbone would also be appreciated.
In my understanding, the "backbone" refers to the feature extracting network which is used within the DeepLab architecture. This feature extractor is used to encode the network's input into a certain feature representation. The DeepLab framework "wraps" functionalities around this feature extractor. By doing so, the feature extractor can be exchanged and a model can be chosen to fit the task at hand in terms of accuracy, efficiency, etc.
In case of DeepLab, the term backbone might refer to models like the ResNet, Xception, MobileNet, etc.
TL;DR Backbone is not a universal technical term in deep learning.
(Disclaimer: yes, there may be a specific kind of method, layer, tool etc. that is called "backbone", but there is no "backbone of a neural network" in general.)
If authors use the word "backbone" as they are describing a neural network architecture, they mean
feature extraction ( a part of the network that "sees" the input), but this interpretation is not quite universal in the field: for instance, in my opinion, computer vision researchers would use the term to mean feature extraction, whereas natural language processing researchers would not.
in informal language, that this part in question is crucial to the overall method.
Backbone is a term used in DeepLab models/papers to refer to the feature extractor network. These feature extractor networks compute features from the input image and then these features are upsampled by a simple decoder module of DeepLab models to generate segmented masks. The authors of DeepLab models have shown performance with different feature extractors (backbones) like MobileNet, ResNet, and Xception network.
CNNs are used for extracting features. Several CNNs are available, for instance, AlexNet, VGGNet, and ResNet(backbones). These networks are mainly used for object classification tasks and have evaluated on some widely used benchmarks and datasets such as ImageNet. In image classification or image recognition, the classifier classifies a single object in the image, outputs a single category per image, and gives the probability of matching a class. Whereas in object detection, the model must be able to recognize several objects in a single image and provides the coordinates that identify the location of the objects. This shows that the detection of objects can be more difficult than the classification of images.
source and more info: https://link.springer.com/chapter/10.1007/978-3-030-51935-3_30

Deep Learning methods for Text Generation (PyTorch)

Greetings to everyone,
I want to design a system that is able to generate stories or poetry based on a large dataset of text, without being needed to feed a text description/start/summary as input at inference time.
So far I did this using RNN's, but as you know they have a lot of flaws. My question is, what are the best methods to achieve this task at the time?
I searched for possibilities using Attention mechanisms, but it turns out that they are fitted for translation tasks.
I know about GPT-2, Bert, Transformer, etc., but all of them need a text description as input, before the generation and this is not what I'm seeking. I want a system able to generate stories from scratch after training.
Thanks a lot!
edit
so the comment was: I want to generate text from scratch, not starting from a given sentence at inference time. I hope it makes sense.
yes, you can do that, that's just simple code manipulation on top of the ready models, be it BERT, GPT-2 or LSTM based RNN.
How? You have to provide random input to the model. Such random input can be randomly chosen word or phrase or just a vector of zeroes.
Hope it helps.
You have mixed up several things here.
You can achieve what you want either using LSTM based or transformer based architecture.
When you said you did it with RNN, you probably mean that you have tried LSTM based sequence to sequence model.
Now, there is attention in your question. So you can use attention to improve your RNN but it is not a required condition. However, if you use transformer architecture, then it is built in the transormer blocks.
GPT-2 is nothing but a transformer based model. Its building block is a transformer architecture.
BERT is also another transformer based architecture.
So to answer your question, you should and can try using LSTM based or transformer based architecture to achieve what you want. Sometimes such architecture is called GPT-2, sometimes BERT depending on how it is realized.
I encourage you to read this classic from Karpathy, if you understand it then you have cleared most of your questions:
http://karpathy.github.io/2015/05/21/rnn-effectiveness/

Azure Machine Learning Data Transformation

Can machine learning be used to transform/modifiy a list of numbers.
I have many pairs of binary files read from vehicle ECUs, an original or stock file before the vehicle was tuned, and a modified file which has the engine parameters altered. The files are basically lists of little or big endian 16 bit numbers.
I was wondering if it is at all possible to feed these pairs of files into machine learning, and for it to take a new stock file and attempt to transform or tune that stock file.
I would appreciate it if somebody could tell me if this is something which is at all possible. All of the examples I've found appear to make decisions on data rather than do any sort of a transformation.
Also I'm hoping to use azure for this.
We would need more information about your specific problem to answer. But, supervised machine learning can take data with a lot of inputs (like your stock file, perhaps) and an output (say a tuned value), and learn the correlations between those inputs and output, and then be able to predict the output for new inputs. (In machine learning terminology, these inputs are called "features" and the output is called a "label".)
Now, within supervised machine learning, there is a category of algorithms called regression algorithms. Regression algorithms allow you to predict a number (sounds like what you want).
Now, the issue that I see, if I'm understanding your problem correctly, is that you have a whole list of values to tune. Two things:
Do those values depend on each other and influence each other? Do any other factors not included in your stock file affect how the numbers should be tuned? Those will need to be included as features in your model.
Regression algorithms predict a single value, so you would need to build a model for each of the values in your stock file that you want to tune.
For more information, you might want to check out Choosing an Azure Machine Learning Algorithm and How to choose algorithms for Microsoft Azure Machine Learning.
Again, I would need to know more about your data to make better suggestions, but I hope that helps.