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Author: torontoai

[D] Counterfactual Explanations

I came across the paper of Wachter, Mittelstadt, et al, who propose Counterfactual Explanations as remedy against the opacity of ML decision-making (see e.g. https://arxiv.org/abs/1711.00399 or https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3278331).

I am a lawyer myself and cannot assess the technical feasibility of this approach. How would you, Ml experts, evaluate their idea? I am really looking forward to your thoughts and insights.

(If this was already subject to discussion elsewhere please kindly direct me to the post).

submitted by /u/Everdream13
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[R] Neural ODEs

We have recently developed an Adjoint based Neural ODE (ANODE) which computes unconditionally accurate gradients for Neural ODEs. This is very important as the approach presented in arxiv:1806.07366 is numerically unstable and may result in divergent training (in several cases we observed >20% accuracy degradation because of this)

Link to Pytorch code:

https://github.com/amirgholami/anode

Link to papers:

https://arxiv.org/pdf/1902.10298.pdf

https://arxiv.org/pdf/1906.04596.pdf

We hope this library would be helpful. Please let us know if you have any feedback and feel free to reach out if there was any questions

submitted by /u/ai_researcherr
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[D] Help with architecture for V2V link duration

Hey all I was wondering if you guys had any recommendations for the type of architecture I should use to estimate the link duration between two vehicles in a VANET.

What I’m thinking right now is to have a MLP network that takes certain parameters (vehicle speed, lane, number of lanes, distance to intersection, traffic conditions, etc.) and feeds the output of that into an LSTM. The reason I suggest an LSTM is because the link duration, or lifetime, is constantly changing based on the parameters that I previously mentioned. To my knowledge an LSTM is good for temporal data. However, I have a feeling that my intuition may be off here and I was wondering if somebody would care to chime in.

Thanks!

submitted by /u/ArminBazz
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[P] PyCM 2.3 released: Machine learning library for confusion matrix statistical analysis

https://www.pycm.ir

https://github.com/sepandhaghighi/pycm

  • Adjusted F-score (AGF) added #209
  • Overlap coefficient (OC) added #212
  • Otsuka-Ochiai coefficient (OOC) added #213
  • save_stat and save_vector parameters added to save_obj method #210
  • Document modified #221
  • README.md modified
  • Parameters recommendation for imbalance dataset modified
  • Minor bug in Compare class fixed
  • pycm_help function modified
  • Benchmarks color modified #221

submitted by /u/sepandhaghighi
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[Project] Similar image search using pre-trained ResNet50 as image embeddings.

Hey guys!

Finished my experimental project where I tried to come up with algorithm to find similar images using pre-trained ResNet50 model for image features generation and cosine similarity as distance metric. At this experiment I used DeepFashion image dataset.

Take a look! https://github.com/tomasrasymas/simimg

submitted by /u/mekass
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[D] Your opinions on my residual deconvolution implementation

[D] Your opinions on my residual deconvolution implementation

I am currently looking for a solution regarding mask generation given an input image, and my approach works as follows:

– conv + activation + max-pooling from the input image until i get to a given smaller size. Every block halves the input size, so expect max-pooling after every convolution

– upsampling + conv + activation until I get back to the input resolution. Expect upsampling before each convolution

Bear with me, this encoder decoder architecture is required, as well as the upsampling + conv instead of transposed convolution (or deconvolution), so take it as given.

The model works as expected, and in order to improve it’s quality I decided to go with residual connections, in particular the full pre-activation variant shown below given it’s improved performance. I am not using BatchNormalization, so don’t take it into account.

rightmost version, no bn

For the encoder, I have each block defined as

– activation of the input

– conv

– max-pooling

– creation of the shortcut, defined as projection + max_pooling of the original input

– addition

Now, the interesting part: I want to build a residual deconvolutional architecture for the decoder, and I’m not entirely sure if what I ended up with is the right way of doing it:

– residual encoder, up to encoded size

– activation (as the last encoder’s residual layer doesn’t have it after the addition

Each block is defined as

– upsampling

– activation

– conv

– creation of the shortcut, defined as upsampling + projection of the original input

– addition

Then I get my mask.

What are your thoughts regarding my approach? using the traditional approach for downsizing the shortcut using convolutions with kernel_size of 1 and strides of 2 loses 75% of information at each step, and I would like to find a way to avoid it.

Thank you for your feedback!

submitted by /u/HitLuca
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[R] Neural Proximal/Trust Region Policy Optimization Attains Globally Optimal Policy

https://arxiv.org/abs/1906.10306

Proximal policy optimization and trust region policy optimization (PPO and TRPO) with actor and critic parametrized by neural networks achieve significant empirical success in deep reinforcement learning. However, due to nonconvexity, the global convergence of PPO and TRPO remains less understood, which separates theory from practice. In this paper, we prove that a variant of PPO and TRPO equipped with overparametrized neural networks converges to the globally optimal policy at a sublinear rate. The key to our analysis is the global convergence of infinite-dimensional mirror descent under a notion of one-point monotonicity, where the gradient and iterate are instantiated by neural networks. In particular, the desirable representation power and optimization geometry induced by the overparametrization of such neural networks allow them to accurately approximate the infinite-dimensional gradient and iterate.

submitted by /u/banananach
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