**Hierarchical Softmax** is a is an alternative to [softmax](https://paperswithcode.com/method/softmax) that is faster to evaluate: it is $O\left(\log{n}\right)$ time to evaluate compared to $O\left(n\right)$ for softmax. It utilises a multi-layer binary tree, where the probability of a word is calculated through the product of probabilities on each edge on the path to that node. See the Figure to the right for an example of where the product calculation would occur for the word "I'm".

(Introduced by Morin and Bengio)

Image Credit: [Steven Schmatz](https://www.quora.com/profile/Steven-Schmatz)

**SSD** is a single-stage object detection method that discretizes the output space of bounding boxes into a set of default boxes over different aspect ratios and scales per feature map location. At prediction time, the network generates scores for the presence of each object category in each default box and produces adjustments to the box to better match the object shape. Additionally, the network combines predictions from multiple feature maps with different resolutions to naturally handle objects of various sizes. 

The fundamental improvement in speed comes from eliminating bounding box proposals and the subsequent pixel or feature resampling stage. Improvements over competing single-stage methods include using a small convolutional filter to predict object categories and offsets in bounding box locations, using separate predictors (filters) for different aspect ratio detections, and applying these filters to multiple feature maps from the later stages of a network in order to perform detection at multiple scales.

SSD: Single Shot MultiBox Detector

Hierarchical Softmax

Mirror-BERT converts pretrained language models into effective universal text encoders without any supervision, in 20-30 seconds. It is an extremely simple, fast, and effective contrastive learning technique. It relies on fully identical *or* slightly modified string pairs as positive (i.e., synonymous) fine-tuning examples, and aims to maximise their similarity during identity fine-tuning.

Year	2000
Data Source	CC BY-SA - https://paperswithcode.com