Attempts to hand-craft algorithms for comprehending human-generated information have largely failed. For example, evaluating the low-level pixels of a picture – such as a car, cat, coat, etc……. – is difficult for a computer to “understand” its semantic value. Color histograms and feature detectors were useful to some extent, although they were rarely accurate in most cases.

The combination of big data and deep learning has fundamentally changed how we approach computer vision, natural language processing, and other machine learning (ML) applications in the last decade; tasks ranging from spam email detection to realistic text-to-video synthesis have made incredible progress, with accuracy metrics on specific tasks reaching superhuman levels. An increase in the use of embedding vectors, or model artifacts formed by taking an intermediate outcome within a deep neural network, is a substantial positive side effect of these advancements.

Training a New Model for Embedding Tasks

On paper, training a new machine learning model and creating embeddings appears simple: take the most up-to-date pre-built model, backed by the most up-to-date architecture, and train it with some data. Isn’t it simple?

Not so quickly. On the surface, employing the most recent model architecture to obtain cutting-edge results may appear simple. However, nothing could be further from the truth. Let’s look at some common training embedding model difficulties (which also apply to conventional machine learning models):

  1. Insufficient data: Overfitting occurs when a new embedding model is trained from scratch without sufficient data. Only the largest worldwide corporations have enough data to justify training a new model from scratch; others must rely on fine-tuning, which involves distilling an already-trained model with a huge dataset using a smaller dataset.
  2. Hyperparameters are constants that affect the training process, such as how rapidly the model learns or how much data is used in a single batch of training. When fine-tuning a model, choosing the right collection of hyperparameters is crucial, as slight changes in certain variables can provide drastically different outcomes. Recent research has also shown that training the same model from scratch with an improved training strategy improved accuracy on ImageNet-1k by over 5% (that’s a lot).
  3. Overestimating self-supervised models: Self-supervision refers to a training technique in which the “fundamentals” of the input data are learned without labels by leveraging the data itself. Self-supervised approaches are ideal for pre-training (for example, training a model with heaps of unlabeled data before fine-tuning it with a smaller labeled dataset), but applying self-supervised embeddings directly can result in inferior performance.
  4. A popular approach to all three of the aforementioned issues is to train a self-supervised model with a large amount of data before fine-tuning it with labeled data. This has been demonstrated to work well for NLP, but not so much for CV.

Using Embedding Models Has Its Pitfalls

These are only a few of the most typical training embedding model errors. As a result, many developers who want to use embeddings start by using pre-trained models on academic datasets like ImageNet (for image classification) and SQuAD (for data mining) (for question answering). Despite the number of pre-trained models accessible nowadays, there are a few traps to avoid in order to get the best embedding performance:

  1. Misalignment of training and inference data: Using an off-the-shelf model trained by other organizations has become a popular technique to construct machine learning applications without putting thousands of GPU/TPU hours into it. Understanding the limits of a particular embedding model and how they affect application performance is critical; it’s easy to misread findings if you don’t understand the model’s training data and technique. A model trained to embed music, for example, will perform poorly when applied to speech, and vice versa.
  2. When utilizing a fully-supervised neural network as an embedding model, features are usually collected from the second-to-last layer of activations (known formally as the penultimate layer). However, depending on the application, this may result in inferior performance. When employing an image classification model to embed images of logos and/or brands, for example, using earlier activations may increase performance. This is owing to the improved preservation of low-level characteristics (edges and corners), which are important for identifying non-complex images.
  3. Nonidentical inference conditions: To get the most out of an embedding model, the train and inference conditions must be identical. In practice, however, this is not always the case. Torchvision’s regular resnet50 model When utilizing bicubic interpolation versus nearest-neighbor interpolation, for example, two completely different outputs are obtained (see below).

Deploying an Embedding Model

Scaling and deploying a model becomes the next crucial step after you’ve cleared all of the difficulties connected with training and validating it. However, embedding model deployment is more difficult said than done. MLOps, a subfield of DevOps, was created particularly for this purpose.

  1. Choosing the right hardware: Embedding models, like most other ML models, can run on a variety of hardware, from ordinary CPUs to programmable logic controllers (FPGAs). Cost versus efficiency considerations has been the subject of entire research papers, underlining the challenge most firms confront in this area.
  2. There are several MLOps and distributed computing platforms available for model deployment (including many open-source ones). It can be difficult enough to figure out how these will fit into your application.
  3. Storage for embedding vectors: As your application grows, you’ll need to find a more permanent and scalable storage solution for your embedding vectors. Vector databases come into play here.

I’ll Learn How to Do It Myself!

ML is not the same as software engineering: Statistics, an area of mathematics that is fundamentally different from software engineering, is where traditional machine learning gets its foundations. Regularization and feature selection are important machine learning topics with deep mathematical origins. While new training and inference libraries (such as PyTorch and Tensorflow) have made it easier to train and build embedding models, knowing how different hyperparameters and training approaches affect embedding model performance remains vital.

It can be difficult to figure out how to use PyTorch or Tensorflow: These libraries have considerably accelerated the training, validation, and deployment of modern machine learning models. Building a new model or implementing an existing one, on the other hand, can be natural for experienced ML developers or programmers who are familiar with HDL. Even yet, the underlying concepts might be difficult to grasp for most software developers. There’s also the issue of deciding which framework to utilize, as the execution engines used by these two frameworks differ significantly (I recommend PyTorch).

It will take time to find an MLOps platform that fits your codebase: A list of MLOps platforms and tools has been compiled. There are hundreds of possibilities to consider, and weighing the advantages and disadvantages of each is a year-long research endeavor in and of itself.

After all of this, I’d like to clarify my previous statement: I admire your enthusiasm, but I don’t suggest learning ML and MLOps. It’s a time-consuming and tiresome procedure that takes time away from what matters most: creating a good product that your consumers will enjoy.

Closing words

Towhee is not a full-fledged, end-to-end model serving or MLOps platform, and that is not what we set out to provide. Rather, we want to speed up the creation of apps that involve embeddings and other machine learning activities. We anticipate that Towhee will allow for rapid prototyping of embedding models and pipelines on your local machine (Pipeline + Trainer), construction of an ML-centric application in only a few lines of code (DataCollection), easy and speedy deployment to your cluster (via Ray).

That’s it for now, guys – I hope you found this article useful. Please leave any questions, comments, or concerns in the box below. Keep an eye out for more!

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