Machine Learning Algorithms: The Types and Models Explained

How do machine learning professionals make data readable and accessible? What techniques do they use to dissect raw information?

One of these techniques is clustering. Data clustering is the process of grouping items in a data set together. These items are related, allowing key stakeholders to make critical strategic decisions using the insights.

After preparing data, which is what specialists do 50%-80% of the time, clustering takes center stage. It forms structures other members of the company can understand more easily, even if they lack advanced technical knowledge.

Clustering in machine learning involves many techniques to help accomplish this goal. Here is a detailed overview of those techniques.

Clustering Techniques

Data science is an ever-changing field with lots of variables and fluctuations. However, one thing’s for sure – whether you want to practice clustering in data mining or clustering in machine learning, you can use a wide array of tools to automate your efforts.

Partitioning Methods

The first groups of techniques are the so-called partitioning methods. There are three main sub-types of this model.

K-Means Clustering

K-means clustering is an effective yet straightforward clustering system. To execute this technique, you need to assign clusters in your data sets. From there, define your number K, which tells the program how many centroids (“coordinates” representing the center of your clusters) you need. The machine then recognizes your K and categorizes data points to nearby clusters.

You can look at K-means clustering like finding the center of a triangle. Zeroing in on the center lets you divide the triangle into several areas, allowing you to make additional calculations.

And the name K-means clustering is pretty self-explanatory. It refers to finding the median value of your clusters – centroids.

K-Medoids Clustering

K-means clustering is useful but is prone to so-called “outlier data.” This information is different from other data points and can merge with others. Data miners need a reliable way to deal with this issue.

Enter K-medoids clustering.

It’s similar to K-means clustering, but just like planes overcome gravity, so does K-medoids clustering overcome outliers. It utilizes “medoids” as the reference points – which contain maximum similarities with other data points in your cluster. As a result, no outliers interfere with relevant data points, making this one of the most dependable clustering techniques in data mining.

Fuzzy C-Means Clustering

Fuzzy C-means clustering is all about calculating the distance from the median point to individual data points. If a data point is near the cluster centroid, it’s relevant to the goal you want to accomplish with your data mining. The farther you go from this point, the farther you move the goalpost and decrease relevance.

Hierarchical Methods

Some forms of clustering in machine learning are like textbooks – similar topics are grouped in a chapter and are different from topics in other chapters. That’s precisely what hierarchical clustering aims to accomplish. You can the following methods to create data hierarchies.

Agglomerative Clustering

Agglomerative clustering is one of the simplest forms of hierarchical clustering. It divides your data set into several clusters, making sure data points are similar to other points in the same cluster. By grouping them, you can see the differences between individual clusters.

Before the execution, each data point is a full-fledged cluster. The technique helps you form more clusters, making this a bottom-up strategy.

Divisive Clustering

Divisive clustering lies on the other end of the hierarchical spectrum. Here, you start with just one cluster and create more as you move through your data set. This top-down approach produces as many clusters as necessary until you achieve the requested number of partitions.

Density-Based Methods

Birds of a feather flock together. That’s the basic premise of density-based methods. Data points that are close to each other form high-density clusters, indicating their cohesiveness. The two primary density-based methods of clustering in data mining are DBSCAN and OPTICS.

DBSCAN (Density-Based Spatial Clustering of Applications With Noise)

Related data groups are close to each other, forming high-density areas in your data sets. The DBSCAN method picks up on these areas and groups information accordingly.

OPTICS (Ordering Points to Identify the Clustering Structure)

The OPTICS technique is like DBSCAN, grouping data points according to their density. The only major difference is that OPTICS can identify varying densities in larger groups.

Grid-Based Methods

You can see grids on practically every corner. They can easily be found in your house or your car. They’re also prevalent in clustering.

STING (Statistical Information Grid)

The STING grid method divides a data point into rectangular grills. Afterward, you determine certain parameters for your cells to categorize information.

CLIQUE (Clustering in QUEst)

Agglomerative clustering isn’t the only bottom-up clustering method on our list. There’s also the CLIQUE technique. It detects clusters in your environment and combines them according to your parameters.

Model-Based Methods

Different clustering techniques have different assumptions. The assumption of model-based methods is that a model generates specific data points. Several such models are used here.

Gaussian Mixture Models (GMM)

The aim of Gaussian mixture models is to identify so-called Gaussian distributions. Each distribution is a cluster, and any information within a distribution is related.

Hidden Markov Models (HMM)

Most people use HMM to determine the probability of certain outcomes. Once they calculate the probability, they can figure out the distance between individual data points for clustering purposes.

Spectral Clustering

If you often deal with information organized in graphs, spectral clustering can be your best friend. It finds related groups of notes according to linked edges.

Comparison of Clustering Techniques

It’s hard to say that one algorithm is superior to another because each has a specific purpose. Nevertheless, some clustering techniques might be especially useful in particular contexts:

• OPTICS beats DBSCAN when clustering data points with different densities.
• K-means outperforms divisive clustering when you wish to reduce the distance between a data point and a cluster.
• Spectral clustering is easier to implement than the STING and CLIQUE methods.

Cluster Analysis

You can’t put your feet up after clustering information. The next step is to analyze the groups to extract meaningful information.

Importance of Cluster Analysis in Data Mining

The importance of clustering in data mining can be compared to the importance of sunlight in tree growth. You can’t get valuable insights without analyzing your clusters. In turn, stakeholders wouldn’t be able to make critical decisions about improving their marketing efforts, target audience, and other key aspects.

Steps in Cluster Analysis

Just like the production of cars consists of many steps (e.g., assembling the engine, making the chassis, painting, etc.), cluster analysis is a multi-stage process:

Data Preprocessing

Noise and other issues plague raw information. Data preprocessing solves this issue by making data more understandable.

Feature Selection

You zero in on specific features of a cluster to identify those clusters more easily. Plus, feature selection allows you to store information in a smaller space.

Clustering Algorithm Selection

Choosing the right clustering algorithm is critical. You need to ensure your algorithm is compatible with the end result you wish to achieve. The best way to do so is to determine how you want to establish the relatedness of the information (e.g., determining median distances or densities).

Cluster Validation

In addition to making your data points easily digestible, you also need to verify whether your clustering process is legit. That’s where cluster validation comes in.

Cluster Validation Techniques

There are three main cluster validation techniques when performing clustering in machine learning:

Internal Validation

Internal validation evaluates your clustering based on internal information.

External Validation

External validation assesses a clustering process by referencing external data.

Relative Validation

You can vary your number of clusters or other parameters to evaluate your clustering. This procedure is known as relative validation.

Applications of Clustering in Data Mining

Clustering may sound a bit abstract, but it has numerous applications in data mining.

• Customer Segmentation – This is the most obvious application of clustering. You can group customers according to different factors, like age and interests, for better targeting.
• Anomaly Detection – Detecting anomalies or outliers is essential for many industries, such as healthcare.
• Image Segmentation – You use data clustering if you want to recognize a certain object in an image.
• Document Clustering – Organizing documents is effortless with document clustering.
• Bioinformatics and Gene Expression Analysis – Grouping related genes together is relatively simple with data clustering.

Challenges and Future Directions

• Scalability – One of the biggest challenges of data clustering is expected to be applying the process to larger datasets. Addressing this problem is essential in a world with ever-increasing amounts of information.
• Handling High-Dimensional Data – Future systems may be able to cluster data with thousands of dimensions.
• Dealing with Noise and Outliers – Specialists hope to enhance the ability of their clustering systems to reduce noise and lessen the influence of outliers.
• Dynamic Data and Evolving Clusters – Updates can change entire clusters. Professionals will need to adapt to this environment to retain efficiency.

Elevate Your Data Mining Knowledge

There are a vast number of techniques for clustering in machine learning. From centroid-based solutions to density-focused approaches, you can take many directions when grouping data.

Mastering them is essential for any data miner, as they provide insights into crucial information. On top of that, the data science industry is expected to hit nearly $26 billion by 2026, which is why clustering will become even more prevalent.

Any tendency or behavior of a consumer in the purchasing process in a certain period is known as customer behavior. For example, the last two years saw an unprecedented rise in online shopping. Such trends must be analyzed, but this is a nightmare for companies that try to take on the task manually. They need a way to speed up the project and make it more accurate.

Enter machine learning algorithms. Machine learning algorithms are methods AI programs use to complete a particular task. In most cases, they predict outcomes based on the provided information.

Without machine learning algorithms, customer behavior analyses would be a shot in the dark. These models are essential because they help enterprises segment their markets, develop new offerings, and perform time-sensitive operations without making wild guesses.

We’ve covered the definition and significance of machine learning, which only scratches the surface of this concept. The following is a detailed overview of the different types, models, and challenges of machine learning algorithms.

Types of Machine Learning Algorithms

A natural way to kick our discussion into motion is to dissect the most common types of machine learning algorithms. Here’s a brief explanation of each model, along with a few real-life examples and applications.

Supervised Learning

You can come across “supervised learning” at every corner of the machine learning realm. But what is it about, and where is it used?

Definition and Examples

Supervised machine learning is like supervised classroom learning. A teacher provides instructions, based on which students perform requested tasks.

In a supervised algorithm, the teacher is replaced by a user who feeds the system with input data. The system draws on this data to make predictions or discover trends, depending on the purpose of the program.

There are many supervised learning algorithms, as illustrated by the following examples:

• Decision trees
• Linear regression
• Gaussian Naïve Bayes

Applications in Various Industries

When supervised machine learning models were invented, it was like discovering the Holy Grail. The technology is incredibly flexible since it permeates a range of industries. For example, supervised algorithms can:

• Detect spam in emails
• Scan biometrics for security enterprises
• Recognize speech for developers of speech synthesis tools

Unsupervised Learning

On the other end of the spectrum of machine learning lies unsupervised learning. You can probably already guess the difference from the previous type, so let’s confirm your assumption.

Definition and Examples

Unsupervised learning is a model that requires no training data. The algorithm performs various tasks intuitively, reducing the need for your input.

Machine learning professionals can tap into many different unsupervised algorithms:

• K-means clustering
• Hierarchical clustering
• Gaussian Mixture Models

Applications in Various Industries

Unsupervised learning models are widespread across a range of industries. Like supervised solutions, they can accomplish virtually anything:

• Segment target audiences for marketing firms
• Grouping DNA characteristics for biology research organizations
• Detecting anomalies and fraud for banks and other financial enterprises

Reinforcement Learning

How many times have your teachers rewarded you for a job well done? By doing so, they reinforced your learning and encouraged you to keep going.

That’s precisely how reinforcement learning works.

Definition and Examples

Reinforcement learning is a model where an algorithm learns through experimentation. If its action yields a positive outcome, it receives an award and aims to repeat the action. Acts that result in negative outcomes are ignored.

If you want to spearhead the development of a reinforcement learning-based app, you can choose from the following algorithms:

• Markov Decision Process
• Bellman Equations
• Dynamic programming

Applications in Various Industries

Reinforcement learning goes hand in hand with a large number of industries. Take a look at the most common applications:

• Ad optimization for marketing businesses
• Image processing for graphic design
• Traffic control for government bodies

Deep Learning

When talking about machine learning algorithms, you also need to go through deep learning.

Definition and Examples

Surprising as it may sound, deep learning operates similarly to your brain. It’s comprised of at least three layers of linked nodes that carry out different operations. The idea of linked nodes may remind you of something. That’s right – your brain cells.

You can find numerous deep learning models out there, including these:

• Recurrent neural networks
• Deep belief networks
• Multilayer perceptrons

Applications in Various Industries

If you’re looking for a flexible algorithm, look no further than deep learning models. Their ability to help businesses take off is second-to-none:

• Creating 3D characters in video gaming and movie industries
• Visual recognition in telecommunications
• CT scans in healthcare

Popular Machine Learning Algorithms

Our guide has already listed some of the most popular machine-learning algorithms. However, don’t think that’s the end of the story. There are many other algorithms you should keep in mind if you want to gain a better understanding of this technology.

Linear Regression

Linear regression is a form of supervised learning. It’s a simple yet highly effective algorithm that can help polish any business operation in a heartbeat.

Definition and Examples

Linear regression aims to predict a value based on provided input. The trajectory of the prediction path is linear, meaning it has no interruptions. The two main types of this algorithm are:

• Simple linear regression
• Multiple linear regression

Applications in Various Industries

Machine learning algorithms have proved to be a real cash cow for many industries. That especially holds for linear regression models:

• Stock analysis for financial firms
• Anticipating sports outcomes
• Exploring the relationships of different elements to lower pollution

Logistic Regression

Next comes logistic regression. This is another type of supervised learning and is fairly easy to grasp.

Definition and Examples

Logistic regression models are also geared toward predicting certain outcomes. Two classes are at play here: a positive class and a negative class. If the model arrives at the positive class, it logically excludes the negative option, and vice versa.

A great thing about logistic regression algorithms is that they don’t restrict you to just one method of analysis – you get three of these:

• Binary
• Multinomial
• Ordinal

Applications in Various Industries

Logistic regression is a staple of many organizations’ efforts to ramp up their operations and strike a chord with their target audience:

• Providing reliable credit scores for banks
• Identifying diseases using genes
• Optimizing booking practices for hotels

Decision Trees

You need only look out the window at a tree in your backyard to understand decision trees. The principle is straightforward, but the possibilities are endless.

Definition and Examples

A decision tree consists of internal nodes, branches, and leaf nodes. Internal nodes specify the feature or outcome you want to test, whereas branches tell you whether the outcome is possible. Leaf nodes are the so-called end outcome in this system.

The four most common decision tree algorithms are:

• Reduction in variance
• Chi-Square
• ID3
• Cart

Applications in Various Industries

Many companies are in the gutter and on the verge of bankruptcy because they failed to raise their services to the expected standards. However, their luck may turn around if they apply decision trees for different purposes:

• Improving logistics to reach desired goals
• Finding clients by analyzing demographics
• Evaluating growth opportunities

Support Vector Machines

What if you’re looking for an alternative to decision trees? Support vector machines might be an excellent choice.

Definition and Examples

Support vector machines separate your data with surgically accurate lines. These lines divide the information into points close to and far away from the desired values. Based on their proximity to the lines, you can determine the outliers or desired outcomes.

There are as many support vector machines as there are specks of sand on Copacabana Beach (not quite, but the number is still considerable):

• Anova kernel
• RBF kernel
• Linear support vector machines
• Non-linear support vector machines
• Sigmoid kernel

Applications in Various Industries

Here’s what you can do with support vector machines in the business world:

• Recognize handwriting
• Classify images
• Categorize text

Neural Networks

The above deep learning discussion lets you segue into neural networks effortlessly.

Definition and Examples

Neural networks are groups of interconnected nodes that analyze training data previously provided by the user. Here are a few of the most popular neural networks:

• Perceptrons
• Convolutional neural networks
• Multilayer perceptrons
• Recurrent neural networks

Applications in Various Industries

Is your imagination running wild? That’s good news if you master neural networks. You’ll be able to utilize them in countless ways:

• Voice recognition
• CT scans
• Commanding unmanned vehicles
• Social media monitoring

K-means Clustering

The name “K-means” clustering may sound daunting, but no worries – we’ll break down the components of this algorithm into bite-sized pieces.

Definition and Examples

K-means clustering is an algorithm that categorizes data into a K-number of clusters. The information that ends up in the same cluster is considered related. Anything that falls beyond the limit of a cluster is considered an outlier.

These are the most widely used K-means clustering algorithms:

• Hierarchical clustering
• Centroid-based clustering
• Density-based clustering
• Distribution-based clustering

Applications in Various Industries

A bunch of industries can benefit from K-means clustering algorithms:

• Finding optimal transportation routes
• Analyzing calls
• Preventing fraud
• Criminal profiling

Principal Component Analysis

Some algorithms start from certain building blocks. These building blocks are sometimes referred to as principal components. Enter principal component analysis.

Definition and Examples

Principal component analysis is a great way to lower the number of features in your data set. Think of it like downsizing – you reduce the number of individual elements you need to manage to streamline overall management.

The domain of principal component analysis is broad, encompassing many types of this algorithm:

• Sparse analysis
• Logistic analysis
• Robust analysis
• Zero-inflated dimensionality reduction

Applications in Various Industries

Principal component analysis seems useful, but what exactly can you do with it? Here are a few implementations:

• Finding patterns in healthcare records
• Resizing images
• Forecasting ROI

Challenges and Limitations of Machine Learning Algorithms

No computer science field comes without drawbacks. Machine learning algorithms also have their fair share of shortcomings:

• Overfitting and underfitting – Overfitted applications fail to generalize training data properly, whereas under-fitted algorithms can’t map the link between training data and desired outcomes.
• Bias and variance – Bias causes an algorithm to oversimplify data, whereas variance makes it memorize training information and fail to learn from it.
• Data quality and quantity – Poor quality, too much, or too little data can render an algorithm useless.
• Computational complexity – Some computers may not have what it takes to run complex algorithms.
• Ethical considerations – Sourcing training data inevitably triggers privacy and ethical concerns.

Future Trends in Machine Learning Algorithms

If we had a crystal ball, it might say that future of machine learning algorithms looks like this:

• Integration with other technologies – Machine learning may be harmonized with other technologies to propel space missions and other hi-tech achievements.
• Development of new algorithms and techniques – As the amount of data grows, expect more algorithms to spring up.
• Increasing adoption in various industries – Witnessing the efficacy of machine learning in various industries should encourage all other industries to follow in their footsteps.
• Addressing ethical and social concerns – Machine learning developers may find a way to source information safely without jeopardizing someone’s privacy.

Machine Learning Can Expand Your Horizons

Machine learning algorithms have saved the day for many enterprises. By polishing customer segmentation, strategic decision-making, and security, they’ve allowed countless businesses to thrive.

With more machine learning breakthroughs in the offing, expect the impact of this technology to magnify. So, hit the books and learn more about the subject to prepare for new advancements.