Gradient Dude
2.54K subscribers
180 photos
50 videos
2 files
169 links
TL;DR for DL/CV/ML/AI papers from an author of publications at top-tier AI conferences (CVPR, NIPS, ICCV,ECCV).

Most ML feeds go for fluff, we go for the real meat.

YouTube: youtube.com/c/gradientdude
IG instagram.com/gradientdude
Download Telegram
​​Most of the Recent Advancements in Transformers are Useless😱
Google Research

Google study shows Transformer Modifications Fail To Transfer Across Implementations and Applications.
The researchers began by reimplementing and evaluating a variety of transformer variants on the tasks where they are most commonly applied. As a baseline, they used the original transformer model with two modifications: applying layer normalization before the self-attention and feed-forward blocks instead of after, and using relative attention with shared biases instead of sinusoidal positional embeddings.

πŸ‘€ Surprise!
Most architecture modifications they looked at do not meaningfully improve performance on downstream NLP tasks - they fail to transfer across implementations and applications. See the table belowπŸ‘‡ with results for transfer learning based on T5, and supervised machine translation on the WMT'14 English-German benchmark.

πŸ˜… Simple ideas are always the best, and more compute never hurts!
Modifications that were proved to improve performance are either (1) relatively simple (e.g. a change in activation function) , or (2) rely on increase in parameter count or FLOPs (e.g. the Switch Transformer or Universal Transformer). And this makes total sense to me.

My take on the reasons for such results is that researchers are often pressured by the urge to publishing new papers every year. This spurs cherry-picking of the results, overstated claims, and spurious architectural modifications. The performance increase shown in many papers is just a result of overfitting over a specific benchmark or more accurate hyperparameter selection compared to the previous work. And such phenomenon is not only inherent for transformer and NLP papers but for other subfields of Deep Learning research as well.

πŸ“ Arxiv paper
Thanks @ai_newz for the pointer!
​​Swin Transformer: New SOTA backbone for Computer VisionπŸ”₯
MS Research Asia

πŸ‘‰ What?
New vision Transformer architecture called Swin Transformer that can serve as a backbone in computer vision instead of CNNs.

❓Why?
There are two main problems with the usage of Transformers for computer vision.
1. Existing Transformer-based models have tokens of a fixed scale. However, in contrast to the word tokens, visual elements can be different in scale (e.g. objects of varying sizes on the scene)
2. Regular self-attention requires quadratic of the image size number of operations, limiting applications in computer vision where high resolution is necessary (e.g., instance segmentation).

πŸ₯Š The main ideas of the Swin Transformers:
1. Hierarchical feature maps where at each level of hierarchy Self-attention is applied within local non-overlapping windows. The size of the windows is progressively increased with the network depth (inspired by CNNs). This enables building architectures similar to feature pyramid networks (FPN) or U-Net for dense pixel-level tasks.
2. Window-based Self-attention reduces the computational overhead.

βš™οΈ Overall Architecture consists of repeating the following blocks:
- Split RGB image into non-overlapping patches (tokens).
- Apply MLP to translate raw features into an arbitrary dimension.
- Apply 2 consecutive Swin Transformer blocks with Window self-attention: both blocks have the same window size, but the second block uses shifted by `patch_size/2` windows which allows information flow between non-overlapping windows.
- Downsampling layer: Reduce the number of tokens by merging neighboring patches in a 2x2 window, and double the feature depth.

🦾 Results
+ Outperforms SOTA by a significant margin on COCO segmentation and detection tasks and ADE20K segmentation.
+ Comparable accuracy to the EfficientNet family on ImageNet-1K classification, while being faster.

πŸ‘ŒπŸ»Conclusion
While Transformers are super flexible, researchers start to inject in Transformers inductive biases similar to those in CNNs, e.g., local connectivity, feature hierarchies. And this seems to help tremendously!

πŸ“ Paper
βš’ Code (promissed soon)
🌐 TL;DR blogpost
This media is not supported in your browser
VIEW IN TELEGRAM
Boston Dynamics unveiled a New Robot for working at warehouses!

Watch Stretch - new case handling robot - move, groove and unload trucks.
Forwarded from Self Supervised Boy
Interactive Weak Supervision paper from ICLR 2021.

In contrast to classical active learning where experts are queried to assess individual samples, the idea of this paper is to assess labeling heuristics being automatically generated. Authors argue that since experts are good in writing such heuristics from scratch, they should be able to label auto-generated heuristics. To be able to rank non-assessed heuristics authors proposed to train an ensemble of models to predict the assessors' mark for the heuristic. As input for these models authors proposed to use fingerprint of the heuristic: concatenated predictions on some subset of data.

There is no very fancy results, there is some concerns raised by reviewers, and there are some strange notations in this paper. Yet the idea looks interesting to me.

With a bit deeper description (and one unanswered question) here.
Source (and rebuttal comments with important links) there.
CvT: Introducing Convolutions to Vision Transformers

Another improvement for Vision transformers! Inject inductive biases of CNNs (i.e. shift, scale, and distortion invariance) to the ViT architecture while maintaining the flexibility of Transformers.

❓How?
Main architectural novelties:
- Hierarchical architecture
- New convolutional token embedding
- Convolutional projections before self-attention instead of the linear which was used in ViT. This is where convolutions come into play.

βœ… Results:
Almost SOTA on Imagenet 1K and 22K: 83.3% and 87.7%.
Almost because Swin Transformers with local window self-attention layers and downsampling layers are a bit stronger (see the image with results) and perhaps faster.

πŸ€” Looks like it is a trend now to incorporate useful structural properties of CNN into Transformers. I'm pretty sure, we will see more papers like this in the next few months.

πŸ“ Paper arxiv.org/abs/2103.15808
New aggregator of trending papersπŸ—ž
It uses number of tweets as a paper hotness score.

You can also create your own reading lists there, add notes about papers and follow other users.

https://42papers.com/

Here is my profile https://42papers.com/u/gradient-dude-933
​​StyleCLIP: Text-Driven Manipulation of StyleGAN Imagery πŸ”₯
Adobe Research

Contrastive Language-Image Pretraining (CLIP) models in order to navigate image editing by text queries.
1. Take pretrained CLIP, pretrained StyleGAN, and pretrained ArcFace network for face recognition.
2. Project an input image in StyleGAN latent vector w_s.
3. Now, given a source latent code w_s∈ W+, and a directive in natural language, or a text prompt t, we iteratively minimize the sum of three losses by changing the latent code w:
a) Distance between generated by StyleGAN image and the text query;
b) Regularization loss penalizing large deviation of the source vector w_s
c) Identity loss, which makes sure that the identity of the generated face is the same as the original one. This is done by minimizing the distance between images in the ArcFace face recognition network embedding space.

Such an image editing process requires iterative optimization of the latent code w (usually 200-300 iterations) for several minutes. To make it faster authors propose a feed-forward method, where instead of optimization, another neural network predicts the residuals which are added to the latent code w to produce the desired image alterations.

The overall idea of the paper is not super novel and has been around for some time already. But this is the first formal paper on such an image editing approach using CLIP and StyleGAN.
Other related papers, recently discussed in this channel:
β–ͺ️Paint by Word
β–ͺ️Using latent space regression to analyze and leverage compositionality in GANs


πŸ“ StyleCLIP Paper
βš™οΈ StyleCLIp code
Cool resultsπŸ‘ŒπŸ»