By Alex Paulen
ON : 16 January 2023
Due to the exponential data growth in the current world, businesses across industries are eager to use machine learning models. Still, they are notoriously difficult and time-consuming to develop from the initial idea to the finished product. While most machine learning (ML) models are developed in a local environment or cloud, they must be deployed to a production context to benefit from it.
Data management, algorithm selection, computing resource management, and model deployment into production are only some of the tasks involved in building and deploying a machine learning model. These models may be utilized to complete business-critical projects and address complex challenges with remarkable ease and effectiveness.
The point of developing an ML model is to address a specific issue; however, this is only possible after the model is out in the wild and used by actual customers. Therefore, deploying models is just as crucial as creating them.
Steps in developing an ML model
1. Data Collection
Data collection is an important step in building a machine learning model, as the quality and quantity of the data can significantly impact the model’s performance. Here are the most important tips for collecting data for a machine-learning model:
- Define the problem and the data requirements: Before collecting data, it is important to clearly define the problem you are trying to solve and the data you will need to solve.
- Gather data from multiple sources: It is generally a good idea because this can help increase the diversity and richness of the data.
- Ensure that the data is relevant: Always make sure that the data you collect is relevant to the problem you are trying to resolve. Collecting data irrelevant to the problem can waste time and resources and negatively impact the model’s performance.
- Consider the quality of the data: The quality of the data can significantly impact the model’s performance. Always collect high-quality data that is accurate and representative of the problem.
- Use a sufficient amount of data: In general, more data is better when it comes to training machine learning models. However, strike a balance between the amount of data you collect and the resources required to collect and process it.
- Label the data appropriately: If you are working with supervised learning algorithms, you must label the data accurately and consistently to indicate the correct output for each input.
2. Data PreProcessing
It prepares the data for use in a machine-learning model. This process involves cleaning and formatting the data to make it suitable for the model. Steps to perform in data preprocessing include:
- Handling missing values: Missing values can occur in the data due to various reasons, such as data entry errors or incomplete records. It is important to handle missing values appropriately, as they can affect the model’s performance. One option is to remove faulty records, which can result in valuable data loss. An alternative is to impute the missing values by estimating them based on the other values in the dataset.
- Outlier detection and removal: Outliers are data points significantly different from the rest. They can occur due to data collection or recording errors, or they may represent valid but rare events. Outliers can seriously impact the model’s performance, so identifying and removing them is usually advisable.
- Feature scaling: Machine learning algorithms use distance-based calculations, so it is critical to scale the features in the data so that they are on a similar scale.
- Feature selection: Not all features in the data may be relevant or valuable for the model. Feature selection selects the most relevant and useful features to use in the model.
3. Data Splitting
It is the process of dividing the available data into training and testing sets. The training set is used to train the machine learning model, while the testing set is used to evaluate the model’s performance on unseen data. There are several approaches to data splitting:
- Simple random sampling is the most basic approach, in which the data is randomly divided into training and testing sets.
- Stratified sampling: This approach is used when the data is imbalanced, i.e., when one class is significantly more prevalent than the others. The data is divided such that the proportion of each class in the training and testing sets is the same as in the original dataset.
- K-fold cross-validation: In this approach, the data is divided into k folds, and the model is trained and evaluated k times, with a different fold being used as the testing set each time. The final evaluation score is the average of the k scores obtained.
- Time series data: When working with time series data, it is vital to maintain the temporal order of the data. One approach is to use a rolling window, where the data is divided into windows of a fixed size, and each window is used as the testing set while the data prior to it is used as the training set.
4. Developing a model
After splitting the data into training and testing sets, the next step is to develop the machine learning model using the training data. It is arguably the toughest step.
- Select an appropriate machine learning algorithm: There are many different machine learning algorithms to choose from, and the appropriate one will depend on the problem’s nature and the data’s characteristics. Consider the type of problem you are trying to solve (e.g., classification, regression, clustering), the size and complexity of the data, and the available resources.
- Train the model: Once you have selected an algorithm, you can use the training data to train the model. This involves feeding the training data to the algorithm and adjusting the model’s parameters to fit the data.
- Fine-tune the model: After training the model, you may need to fine-tune it to improve its performance. This may involve adjusting the model’s hyperparameters, such as the learning rate or the regularization coefficient. You can use various techniques, for instance, grid search or random search, to find the optimal values of the hyperparameters.
5. Model Evaluation
Model evaluation is the process of assessing the performance of a machine-learning model on unseen data. It is an important step in the model development process, as it helps determine how well the model can generalize to new data. You can use several metrics to evaluate a machine learning model, depending on the nature of the problem and the model type.
Some standard evaluation metrics include:
- Accuracy: This metric measures the proportion of correct predictions made by the model. It is often used for classification problems and is calculated as the number of correct predictions divided by the total number of predictions.
- Precision: This metric measures the proportion of correct positive predictions. It is often used for classification problems and is calculated as the number of true positives divided by the sum of true positives and false positives.
- Recall: This metric measures the proportion of actual positive cases correctly predicted by the model. It is also often used for classification problems and is calculated as the number of true positives divided by the sum of true positives and false negatives.
- F1 score: This metric is the harmonic mean of precision and recall and is calculated as the product of precision and recall divided by their sum.
- Mean squared error (MSE): This metric is used for regression problems and measures the average squared difference between predicted and true values.
- Root mean squared error (RMSE): This metric is the square root of the MSE and is used to scale the error to the same units as the original data.
6. Model Deployment
Model deployment refers to the process of making a machine-learning model available for use in production.
- Integrating the model into an application: If you have developed a model for a specific application, you can integrate the model into the application by calling the model’s prediction function as needed.
- Making the model available as a web service: You can also deploy the model as a web service, which can be accessed via an API. This allows other applications or systems to use the model by requesting the API.
- Deploying the model on a cloud platform: Several cloud platforms provide services for deploying machine learning models, such as Amazon SageMaker and Google Cloud AI Platform. These platforms handle the underlying infrastructure and provide tools for managing and deploying the model.
Regardless of the approach you choose, it is important to consider the following factors when deploying a machine-learning model:
- Performance: The model should be able to handle the expected workload and provide fast and accurate predictions.
- Scalability: The model should handle an increase in the volume of requests without a significant drop in performance.
- Maintenance: You will need to monitor the model’s performance and update it as needed to ensure it continues to meet the required performance and accuracy standards.
How can you deploy an ML model?
To move a machine-learning model into the deployed environment, you will need to consider the following steps:
- Choose a deployment platform:
There are several options for deploying a machine learning model, including integrating it into an application, making it available as a web service, or deploying it on a cloud platform. Consider the requirements of the application or system that will be using the model and the resources and expertise available.
- Prepare the deployment model:
Depending on the chosen deployment platform, you may need to prepare the model for deployment by converting it to a suitable format, wrapping it in an API, or packaging it in a container.
- Test the deployed model:
It is important to thoroughly test it to ensure it is reliable and performs as expected. This may involve evaluating the model on a separate testing dataset or using techniques such as cross-validation to get a more robust estimate of its performance.
- Deploy the model:
Once it is prepared for deployment and has been tested, you can deploy it according to the chosen platform. This may involve uploading the model to a cloud platform, deploying it on a server, or integrating it into an application.
Automate the deployment pipeline and testing workflows
You can use tools such as Jenkins or GitLab CI/CD to automate the deployment pipeline and test workflows for a machine learning model. These tools allow you to define a pipeline that includes all the steps involved in building, testing, and deploying the model, and they can automatically execute the pipeline when certain conditions are met, such as changes to the codebase or new data becoming available.
Here are the general steps involved in automating the deployment pipeline:
- Set up the automation tool: Install and configure the chosen automation tool on the server or cloud platform where you will be deploying the model.
- Define the pipeline: Use the automation tool to define the pipeline that includes all the steps involved in building, testing, and deploying the model. This may comprise fetching the code from version control, building the model, running tests, and deploying the model to production.
- Configure triggers: Configure the pipeline automatically based on certain conditions, such as changes to the codebase or new data becoming available.
- Run the pipeline: Execute the pipeline to build, test, and deploy the model. The automation tool will handle the execution of the pipeline and provide reports on the status of each step.
Make the model accessible to the end users by providing them with the necessary information and tools. This may involve providing them with an API endpoint or user interface or integrating the model into an existing application.
Once the model is prepared for deployment, you can deploy it according to the chosen method. This may involve uploading the model to a cloud platform, deploying it on a server, or integrating it into an application.
Monitoring of Model
Model monitoring is tracking the performance and behavior of a machine learning model over time. It is an important step in the model deployment process, as it helps ensure that the model meets the required performance and accuracy standards.
Here are some key considerations for monitoring a machine-learning model:
- Data: Monitor the model using a combination of training data, validation data, and real-world data to get a comprehensive view of the model’s performance.
- Alerts: Set alerts to notify you if the model’s performance drops below a certain threshold or if there are any other issues.
- Visualizations: Use visualizations to help you understand the model’s performance over time and identify trends or patterns.
- Regular updates: Monitor the model regularly and update it as needed to ensure it continues to perform well.
How to select a machine learning model?
There are several factors to consider when selecting a machine learning model, including:
- Evaluating the available data: Assess the quality and quantity of the data you have available for training the model.
- Considering the resources available: Consider the resources that you have available, including computational power and time, as well as the team’s expertise.
- Considering the interpretability of the model: Depending on the problem, it may be important to select a model that is interpretable and can provide insights into the relationships and patterns in the data.
- Comparing multiple models: Train and evaluate multiple models using cross-validation to get a more robust estimate of their performance.
- Considering the deployment environment: Consider the environment where the model will be deployed, including the available resources and infrastructure.
How to tune hyperparameters for optimal performance?
Here are some general guidelines for tuning hyperparameters for optimal performance:
- Define the hyperparameter search space: Determine the range of values each can take.
- Choose a hyperparameter tuning method: There are several methods for hyperparameter tuning, including grid search, random search, and Bayesian optimization. Choose a method appropriate for the model’s complexity and the resources available.
Once you have selected the best-performing model, you may want to further fine-tune the model by selecting a smaller range of values for the hyperparameters and repeating the training and evaluation process.
What are the tools for model deployment?
- TensorFlow Serving: This is a flexible, high-performance serving system for deploying TensorFlow models. It can be used to serve a single model or multiple models at the same time.
- AWS SageMaker: This fully managed service allows you to build, train, and deploy machine learning models. It includes built-in algorithms and integrations with popular libraries like TensorFlow, PyTorch, and scikit-learn.
- Azure Machine Learning: This is a cloud-based service for building, training, and deploying machine learning models. It includes many tools and features, such as automated machine learning and a visual interface for building and deploying models.
- Google Cloud AI Platform: This is a cloud-based platform for training, deploying, and managing machine learning models. It includes various tools and services, such as pre-trained models, batch and stream prediction, and hyperparameter tuning.
- FloydHub: This is a cloud platform for training and deploying machine learning models. It provides various tools and features, such as a command-line interface and support for popular libraries like TensorFlow, PyTorch, and scikit-learn.
In summary, building a machine learning model involves several steps, including collecting and preprocessing data, splitting the data into training and test sets, developing and evaluating the model, and deploying and maintaining the model. It is important to carefully consider each step and choose the appropriate methods and tools.
By following these steps and best practices, you can effectively build and deploy machine learning models that are accurate, reliable, and suitable for the intended use case.