**Detr**, or **Detection Transformer**, is a set-based object detector using a [Transformer](https://paperswithcode.com/method/transformer) on top of a convolutional backbone. It uses a conventional CNN backbone to learn a 2D representation of an input image. The model flattens it and supplements it with a positional encoding before passing it into a transformer encoder. A transformer decoder then takes as input a small fixed number of learned positional embeddings, which we call object queries, and additionally attends to the encoder output. We pass each output embedding of the decoder to a shared feed forward network (FFN) that predicts either a detection (class
and bounding box) or a “no object” class.

Detr

End-to-End Object Detection with Transformers

Firefly algorithm

Firefly Algorithm for optimization problems with non-continuous variables: A Review and Analysis

**Residual Normal Distributions** are used to help the optimization of VAEs, preventing optimization from entering an unstable region. This can happen due to sharp gradients caused in situations where the encoder and decoder produce distributions far away from each other. The residual distribution parameterizes $q\left(\mathbf{z}|\mathbf{x}\right)$ relative to $p\left(\mathbf{z}\right)$. Let $p\left(z^{i}\_{l}|\mathbf{z}\_{<l}\right) := N \left(\mu\_{i}\left(\mathbf{z}\_{<l}\right), \sigma\_{i}\left(\mathbf{z}\_{<l}\right)\right)$ be a Normal distribution for the $i$th variable in $\mathbf{z}\_{l}$ in prior. Define $q\left(z^{i}\_{l}|\mathbf{z}\_{<l}, x\right) := N\left(\mu\_{i}\left(\mathbf{z}\_{<l}\right) + \Delta\mu\_{i}\left(\mathbf{z}\_{<l}, x\right), \sigma\_{i}\left(\mathbf{z}\_{<l}\right) \cdot \Delta\sigma\_{i}\left(\mathbf{z}\_{<l}, x\right) \right)$, where $\Delta\mu\_{i}\left(\mathbf{z}\_{<l}, \mathbf{x}\right)$ and $\Delta\sigma\_{i}\left(\mathbf{z}\_{<l}, \mathbf{x}\right)$ are the relative location and scale of the approximate posterior with respect to the prior. With this parameterization, when the prior moves, the approximate posterior moves accordingly, if not changed.

Source	Firefly Algorithm for optimization problems with non-continuous variables: A Review and Analysis
Year	2000
Data Source	CC BY-SA - https://paperswithcode.com