Angela  Dickens

Angela Dickens

1595047860

Attention in GANs (Generative Adversarial Networks)

In 2017, the paper “Attention is all you need”shocked the land of NLP (Natural Language Processing). It was shocking not only because it has a good paper title, but also because it introduced to the world a new model architecture called “Transformer”, which proved to perform much better than the traditional RNN type of networks and paved its way to the state of the art NLP model “BERT”.

This stone cast in the pond of NLP has created ripples in the pond of GANs (Generative Adversarial Networks). Many have been inspired by this and attempt to garner the magic power of attention. But when I first started reading papers about using attention in GANs, it appeared to me there are so many different meanings behind the same “attention” word. In case you are as confused as I was, let me be at your service and shed some light on what people really mean when they say they use “attention” in GANs.

Meaning 1: Self-attention

Self-attention in GANs is very similar to the mechanism in the NLP Transformer model. Basically, it addresses the difficulty of the AI model in understanding long-range dependency.

In NLP, the problem arises when there is a long sentence. Take the example of this Oscar Wilde’s quote _“To __live _is the rarest thing in the world. Most people exist, that is all.” The two words in bold (“live” and “exist”) have a relationship, but they are placed far apart from each other which makes it hard for the RNN type of AI model to capture the relationship.

It is almost the same in GANs, most of GANs use CNN structure which is good at capturing local features and may overlook the long-range dependency when it is outside of its receptive field. As a result, it is easy for GANs to generate realistic-looking furs on dogs, but it may make a mistake by generating a dog with 5 legs.

Self-Attention Generative Adversarial Networks(SAGAN) adds a self-attention module to guide the model to look at features at distant portions of the image. In the pictures below, the picture on the left is the generated image, with some sample locations labeled with color dots. The other images showing the corresponding attention map of the locations. I find the most interesting one is the 5th image with the cyan dot. It shows that when the model generates the left ear of the dog, it not only looks at the local region around the left ear but also looks at the right ear.

Image for post

Visualization of the attention map for the color labeled locations. source

If you are interested in the technical details of SAGAN, other than reading the paper, I also recommend this post.

Meaning 2: Attention in the discriminator

GANs consist of a generator and a discriminator. In the GANs world, they are like two gods eternally at war, where the generator god tirelessly creates, and the discriminator god stands at the side and criticizes how bad these creations are. It may sound like the discriminator is the bad god, but that is not true. It is through these criticisms that the generator god knows how to improve.

If these “criticisms” from discriminator are so helpful, why not we pay more attention to them? Let’s see how this paper “U-GAT-IT: Unsupervised Generative Attentional Networks with Adaptive Layer-Instance Normalization for Image-to-Image Translation_” _does this.

The project U-GAT-IT tackles a difficult task — converts a human photo into a Japanese anime image. It is difficult because an anime character’s face is vastly different from a real person’s face. Take an example of the pair images below. The anime character on the right is deemed as a good conversion from the person on the left. But is we put ourselves in the computer’s shoes for a moment, we will see that the eyes, nose, and mouth in the two images are very different, the structure and proportion of the face also changes a lot. It is very hard for a computer to know what features to preserve and what to modify.

#machine-learning #gans #neural-networks #deep-learning #generative-model #deep learning

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Attention in GANs (Generative Adversarial Networks)
Angela  Dickens

Angela Dickens

1595047860

Attention in GANs (Generative Adversarial Networks)

In 2017, the paper “Attention is all you need”shocked the land of NLP (Natural Language Processing). It was shocking not only because it has a good paper title, but also because it introduced to the world a new model architecture called “Transformer”, which proved to perform much better than the traditional RNN type of networks and paved its way to the state of the art NLP model “BERT”.

This stone cast in the pond of NLP has created ripples in the pond of GANs (Generative Adversarial Networks). Many have been inspired by this and attempt to garner the magic power of attention. But when I first started reading papers about using attention in GANs, it appeared to me there are so many different meanings behind the same “attention” word. In case you are as confused as I was, let me be at your service and shed some light on what people really mean when they say they use “attention” in GANs.

Meaning 1: Self-attention

Self-attention in GANs is very similar to the mechanism in the NLP Transformer model. Basically, it addresses the difficulty of the AI model in understanding long-range dependency.

In NLP, the problem arises when there is a long sentence. Take the example of this Oscar Wilde’s quote _“To __live _is the rarest thing in the world. Most people exist, that is all.” The two words in bold (“live” and “exist”) have a relationship, but they are placed far apart from each other which makes it hard for the RNN type of AI model to capture the relationship.

It is almost the same in GANs, most of GANs use CNN structure which is good at capturing local features and may overlook the long-range dependency when it is outside of its receptive field. As a result, it is easy for GANs to generate realistic-looking furs on dogs, but it may make a mistake by generating a dog with 5 legs.

Self-Attention Generative Adversarial Networks(SAGAN) adds a self-attention module to guide the model to look at features at distant portions of the image. In the pictures below, the picture on the left is the generated image, with some sample locations labeled with color dots. The other images showing the corresponding attention map of the locations. I find the most interesting one is the 5th image with the cyan dot. It shows that when the model generates the left ear of the dog, it not only looks at the local region around the left ear but also looks at the right ear.

Image for post

Visualization of the attention map for the color labeled locations. source

If you are interested in the technical details of SAGAN, other than reading the paper, I also recommend this post.

Meaning 2: Attention in the discriminator

GANs consist of a generator and a discriminator. In the GANs world, they are like two gods eternally at war, where the generator god tirelessly creates, and the discriminator god stands at the side and criticizes how bad these creations are. It may sound like the discriminator is the bad god, but that is not true. It is through these criticisms that the generator god knows how to improve.

If these “criticisms” from discriminator are so helpful, why not we pay more attention to them? Let’s see how this paper “U-GAT-IT: Unsupervised Generative Attentional Networks with Adaptive Layer-Instance Normalization for Image-to-Image Translation_” _does this.

The project U-GAT-IT tackles a difficult task — converts a human photo into a Japanese anime image. It is difficult because an anime character’s face is vastly different from a real person’s face. Take an example of the pair images below. The anime character on the right is deemed as a good conversion from the person on the left. But is we put ourselves in the computer’s shoes for a moment, we will see that the eyes, nose, and mouth in the two images are very different, the structure and proportion of the face also changes a lot. It is very hard for a computer to know what features to preserve and what to modify.

#machine-learning #gans #neural-networks #deep-learning #generative-model #deep learning

Paper Reading on Generative Adversarial Nets

Generative Adversarial Nets

The main idea is to develop a generative model via an adversarial process. We will discuss what is an adversarial process later. GAN consists of two model. The one is generative model G and the other is discriminative model D. The purpose of a generative model is to generate the closest data as possible for give some input. The purpose of a discriminative model between two classes 0 and 1. 0 meaning the class belongs to Generative output and 1 meaning the class belongs to the true input sample from the original data.

This architecture corresponds to the minmax two-player game. One tries to create conflict over the other. Such networks are called adversarial networks. In the process of creating conflicts, both of them learn to be better and stronger than each other. When the discriminator makes an output of value ½ or 0.5, it implies that the discriminator is not able to distinguish whether the value came from the generator output or the original sample.

Here, the G and D are defined by the multilayered perceptron such that the entire system can be trained with back propagation. The training of the discriminator and generator are done separately.

According to the paper, the generative model can be thought of as analogous to a team of counterfeiters who are trying to produce a fake currency and use them without getting caught.

While, the discriminative model can be thought of as analogous to the Police who are trying to detect the fake currency. Here, both the teams try to improve their methods until the currencies are indistinguishable from the original currency.

Adversarial Networks

Straight from the paper,

To learn the generator’s distribution Pg over data x, we define a prior on input noise variables Pz(z), then represent a mapping to data space as G(z; θg ).

where G is a differentiable function represented by a multilayer perceptron with parameters θ g .

We also define a second multilayer perceptron D(x; θd ) that outputs a single scalar.

Where D(x) represents the probability that x came from the data rather than Pg.

The architecture of GAN can be explained from the following figure.

Image for post

#generative-adversarial #discriminator #adversarial-network #deep-learning #neural-networks

Self-Attention Generative Adversarial Networks (SAGAN)

Introduction

In my effort to better understand the concept of self-attention, I tried dissecting one of its particular use cases on one of my current deep learning subtopic interests: Generative Adversarial Networks (GANs). As I delved deeply into the Self-Attention GAN (or “SAGAN”) research paper, while following similar implementations on Pytorch and Tensorflow in parallel, I noticed how exhausting it could get to power through the formality and the mathematically intense blocks to arrive at a clear intuition of the paper’s contents. Although I get that formal papers are written that way for precision of language, I do think there’s a need for bite-sized versions that define the prerequisite knowledge needed and also lay down the advantages and disadvantages candidly.

In this article, I am going to try to make a computationally efficient interpretation of the SAGAN without reducing too much of the accuracy for the “hacky” people out there who want to just get started (Wow, so witty).

So, here’s how I’m going to do it:

  • What do I need to know?
  • What is it? Who made it?
  • What does it solve? Advantages and Disadvantages?
  • Possible further studies?
  • Source/s

What do I need to know?

  • Basic Machine Learning and Deep Learning concepts (Dense Layers, Activation Functions, Optimizers, Backpropagation, Normalization, etc.)
  • Vanilla GAN
  • Other GANs: Deep Convolutional GAN (DCGAN), Wasserstein GANs (WGAN)
  • Convolutional Neural Networks — Intuition, Limitations and Relational Inductive Biases (Just think of this as assumptions)
  • Spectral Norms and the Power Iteration Method
  • Two Time-Scale Update Rule (TTUR)
  • Self-Attention

#attention #deep-learning #machine-learning #data-science #generative-adversarial #deep learning

amelia jones

1591340335

How To Take Help Of Referencing Generator

APA Referencing Generator

Many students use APA style as the key citation style in their assignment in university or college. Although, many people find it quite difficult to write the reference of the source. You ought to miss the names and dates of authors. Hence, APA referencing generator is important for reducing the burden of students. They can now feel quite easy to do the assignments on time.

The functioning of APA referencing generator

If you are struggling hard to write the APA referencing then you can take the help of APA referencing generator. It will create an excellent list. You are required to enter the information about the source. Just ensure that the text is credible and original. If you will copy references then it is a copyright violation.

You can use a referencing generator in just a click. It will generate the right references for all the sources. You are required to organize in alphabetical order. The generator will make sure that you will get good grades.

How to use APA referencing generator?

Select what is required to be cited such as journal, book, film, and others. You can choose the type of required citations list and enter all the required fields. The fields are dates, author name, title, editor name, and editions, name of publishers, chapter number, page numbers, and title of journals. You can click for reference to be generated and you will get the desired result.

Chicago Referencing Generator

Do you require the citation style? You can rely on Chicago Referencing Generator and will ensure that you will get the right citation in just a click. The generator is created to provide solutions to students to cite their research paper in Chicago style. It has proved to be the quickest and best citation generator on the market. The generator helps to sort the homework issues in few seconds. It also saves a lot of time and energy.

This tool helps researchers, professional writers, and students to manage and generate text citation essays. It will help to write Chicago style in a fast and easy way. It also provides details and directions for formatting and cites resources.

So, you must stop wasting the time and can go for Chicago Referencing Generator or APA referencing generator. These citation generators will help to solve the problem of citation issues. You can easily create citations by using endnotes and footnotes.

So, you can generate bibliographies, references, in-text citations, and title pages. These are fully automatic referencing style. You are just required to enter certain details about the citation and you will get the citation in the proper and required format.

So, if you are feeling any problem in doing assignment then you can take the help of assignment help.
If you require help for Assignment then livewebtutors is the right place for you. If you see our prices, you will observe that they are actually very affordable. Also, you can always expect a discount. Our team is capable and versatile enough to offer you exactly what you need, the best services for the prices you can afford.

read more:- Are you struggling to write a bibliography? Use Harvard referencing generator

#apa referencing generator #harvard referencing generator #chicago referencing generator #mla referencing generator #deakin referencing generator #oxford referencing generator

Sequential Image Generation with GANs

Generative Adversarial Networks (GANs) are very successful in generating very sharp and realistic images. This post briefly explains our image generation framework based on GANs to sequentially compose an image scene, breaking down the underlying problem into smaller ones. For an in-depth description, please see our publication: A Layer-Based Sequential Framework for Scene Generation with GANs.

Image for post

Fig. 1: The proposed image generation process. Given a semantic layout map, our model composes the scene step-by-step. The first row shows the input semantic map and images generated by state-of-the-art baselines.

What is Generative Adversarial Network (GAN)?

Image for post

Fig. 2: GAN framework.

A generative adversarial network (GAN) [1] is a class of machine learning frameworks. Two neural networks: (i) generator, and (ii) discriminator contest with each other in a game-theoretic scenario. The generator takes a random noise as an input and generates a fake sample. The discriminator attempts to distinguish between samples drawn from the training dataset (real samples e.g hand-written digit images) and samples produced by the generative model (fake samples). This game drives the discriminator to learn to correctly classify samples as real or fake. Simultaneously, the generator attempts to fool the classifier into believing its samples are real. At convergence, the generators samples are indistinguishable from training data. For more details, please see the original paper or this post. GANs can be used for image generation; they are able to learn to generate sharp and realistic image data.

Single-shot image generation limits user control over the generated elements

Image for post

Fig. 3: Different scaling of the foreground object.

The automatic image generation problem has been studied extensively in the GAN literature [2,3,4]. It has mostly been addressed as learning a mapping from a single source, e.g. noise or semantic map, to target, e.g. images of zebras. This formulation sets a major restriction on the ability to control scene elements individually. So for instance, it is difficult to change the appearance or shape of one zebra while keeping the rest of the image scene unaltered. Let’s look at Fig. 3. If we change the object size, the background is also changed even though the input noise is the same for each row.

Our approach: Layer-based Sequential Image Generation

Our main idea resembles how a landscape painter would first sketch out the overall structure and later embellish the scene gradually with other elements to populate the scene. For example, the painting could start with mountain ranges or rivers as background while trees and animals are added sequentially as foreground instances.

The main objective is broken down into two simpler sub-tasks. First, we generate the background canvas** x0** with the background generator Gbg conditioned on a noise. Second, we sequentially add foreground objects with the foreground generator Gfg to reach the final image xT, which contains the intended T foreground objects on the canvas (T is not fixed). Our model allows user control over the objects to generate, as well as, their category, their location, their shape, and their appearance.

#image-generation #generative-adversarial #deep-learning #gans #ai #deep learning