Making sense of neural networks in AI Alex, June 13, 2023June 29, 2023 If you’ve ever taken a glimpse into the vibrant world of artificial intelligence (AI) and machine learning, you’ve undoubtedly come across the term “neural networks”. Yet, this might raise a few questions: “What exactly is a neural network, and why is it so crucial in the field of AI and machine learning?”, a question that could be one of them. In this guide, we’re going to unravel the complexities of neural networks in a beginner-friendly manner that won’t make your head hurt. So, what exactly is a neural network? In essence, a neural network is a system inspired by the human brain’s biological neural networks. These networks consist of interconnected nodes, or “neurons,” that work in unison to solve specific problems. These problems range from image recognition to language translation, and even to making predictions about complex financial markets. Let’s take the example of a neural network used for image recognition. Suppose we give a neural network hundreds of thousands of images of faces, each tagged with various descriptions such as age, gender, emotion, and more. Over time, the neural network will learn from this information, enabling it to make educated guesses when presented with new images. It could guess a person’s age or emotional state just by analyzing a fresh image. Now, imagine that we present this neural network with a new image – an image it has never seen before. Leveraging its previous learning, the network can analyze this image and make an educated guess about the person’s age, gender, and emotional state. This ability of neural networks to learn from the past and apply that knowledge to new, unseen data is what makes them invaluable in numerous applications of AI and machine learning. A journey through time: The history of neural networks The concept of a machine that could think like a human has a much longer history than many realize. The groundwork for modern neural networks was proposed independently by Alexander Bain in 1873 and William James in 1890. They both suggested that both thoughts and bodily activities resulted from interactions among neurons within the brain. Over the years, this foundation was built upon and refined, leading to the neural networks we know today. Frank Rosenblatt, in 1958, developed the perceptron, an algorithm for pattern recognition, which was a monumental step in the progression of neural networks. However, the field of neural network research faced some stagnation after Marvin Minsky and Seymour Papert highlighted some key issues with the computational machines of the time in 1969. This stagnation was temporary, and as computers became more powerful, they were better equipped to handle the complexities and requirements of large neural networks. The building blocks of neural networks The architecture of deep neural networks involves several hidden layers, each layer composed of millions of artificial neurons. These layers are interconnected through “weights,” which, in layman’s terms, denote the importance or influence of one node over another. The higher the weight value, the stronger its influence. There are various types of artificial neural networks. They differ mainly in how data flows from the input node (where data is introduced) to the output node (where we get our result). A few examples include feedforward neural networks, where data processes in a single direction from input to output, and convolutional neural networks, which are particularly useful for image recognition tasks. Decoding the training process of neural networks Think of a neural network as a learner or a student. Just as a student learns from textbooks, lectures, and practical exercises, a neural network learns from data – lots and lots of it. This learning process is often referred to as ‘training’. It involves inputting vast amounts of data into the network, letting it process the data, and then adjusting the network based on the outcomes. Consider a common type of machine learning known as supervised learning. In supervised learning, a neural network is given datasets that already contain the correct answer. This is akin to a student studying a textbook that provides the right solutions to problems at the end of each chapter. By working through the problems and comparing their answers to the correct ones, students understand where they went wrong and learn how to get it right the next time. A neural network operates similarly. When we train it with labeled data – data that comes with the correct answer – the network makes its own predictions. Then, it checks these predictions against the actual answers. If there are differences between its predictions and the actual answers, the network makes note of them. This difference is often referred to as ‘error’. The goal of the training process is to minimize this error. To achieve this, the network uses an algorithm called “backpropagation”. Backpropagation is like a feedback mechanism. It guides the network in adjusting its internal parameters, helping it get closer to the correct output. This process repeats with each piece of data in the training set until the network’s predictions align closely with the actual answers. After sufficient training, the neural network will have learned how to make accurate predictions for the kind of data it was trained on. Now, when we feed it new, unseen data, it can apply what it learned from the training phase and give us the output we need. This is why neural networks are a vital tool in AI and machine learning – they’re capable of learning from the past and applying this knowledge to future data. Basically, the training of a neural network is a repetitive but refined process of learning, adjusting, and evolving. It’s through this intricate process that these networks develop the ability to carry out tasks ranging from recognizing images to predicting stock market trends. Deep learning: A subset of machine learning While machine learning provides computers with vast datasets and teaches them to learn from this data, deep learning takes it a step further. Deep learning networks can process raw data independently, analyzing unstructured datasets like text documents, identifying which attributes to prioritize, and solving more complex problems. To clarify with an example, let’s imagine training software to identify an image of a pet. In traditional machine learning, you’d manually label images of various pets and tell the software what features to look for. On the other hand, deep learning lets the neural network process all images and determine what features it should analyze to recognize a pet. Recurrent neural networks Recurrent Neural Networks (RNNs) are a type of artificial neural network that can process sequential data by retaining information from previous steps. They are especially well-suited for time series analysis, natural language processing, speech recognition, and other jobs where data order and context are critical. Unlike feedforward neural networks, in which information travels from input to output in a single direction, RNNs feature connections that create a directed cycle, allowing them to preserve a hidden state or memory of prior inputs. At each step of the sequence, this hidden state is updated, and it effects both the current output and the current input. The capacity of RNNs to accommodate variable-length input sequences is its distinguishing feature. Each RNN step accepts an input and outputs an output that can be utilized as the input for the following phase. RNNs can capture dependencies and patterns in sequential data across time because of their recursive nature. Traditional RNNs, on the other hand, suffer from the “vanishing gradient” problem, making it impossible to capture long-term dependencies. To solve this issue, numerous modifications, such as Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) cells, have been created. These updated RNN architectures include techniques for selectively retaining or forgetting information in the hidden state, which improves their ability to detect long-term dependencies. Neural networks and the field of neuroscience Neural networks take their name and inspiration from the complex structures in our brains. Each neuron in our brain communicates with many others to carry out tasks. It’s this structure and form of communication that forms the basis of artificial neural networks. They aim to imitate the brain’s ability to learn from experience and adapt to new circumstances. Potential applications of neural networks Neural networks have a wide range of applications due to their ability to learn and solve complex problems. They are instrumental in areas like: Image and speech recognition: Neural networks excel at recognizing patterns, which is essential for image and speech recognition. Healthcare: Neural networks can predict diseases, help with diagnosis, and even aid in creating personalized treatment plans. Financial market analysis: Neural networks can analyze financial data and predict market trends, offering valuable insights for investors. Autonomous Vehicles: Neural networks play a crucial role in the functioning of autonomous vehicles, interpreting sensory data to identify obstacles and make safe driving decisions. Pros and cons of neural networks Advantages Neural networks have several advantages that make them particularly useful: Adaptability: Neural networks can learn and improve their performance over time as they are exposed to more data. Parallel processing: They are capable of performing multiple tasks at the same time, which makes them efficient at handling large datasets. Fault tolerance: If one neuron fails, it won’t halt the entire process, much like how the human brain operates. Versatility: They are applicable to a wide range of tasks, from speech and image recognition to predictive analytics. Disadvantages Despite their many advantages, neural networks also have some limitations: Data dependence: They require large amounts of data to learn effectively. Transparency: Neural networks, particularly deep learning models, are often seen as “black boxes” because it’s hard to understand how they reach their decisions. Overfitting: Neural networks can sometimes get too specialized in the training data, which makes them less effective at generalizing to new, unseen data. Computational requirements: They require high-end hardware for their computation, especially for complex tasks. Neural networks: A brief conclusion In conclusion, neural networks are an impressive tool in AI and machine learning, paving the way for groundbreaking advancements in many fields. They’re basically a testament to the intersection of technology and human ingenuity, bringing us one step closer to machines that can think and learn just like we do. As we delve deeper into the world of AI, who knows what fascinating innovations are just around the corner? Remember, understanding neural networks is a journey, not a destination. The field is constantly evolving, and there is always more to learn. So, keep exploring, keep learning, and most importantly, keep asking questions! AI Talk