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Glossary

All concepts from A to Z.

A

  • Adversarial Network

    Adversarial Networks, in particular Generative Adversarial Networks (GANs), are a class of AI systems that consist of two competing neural networks. GANs were introduced by Ian Goodfellow in 2014 and are used to generate synthetic data that closely resembles real-world data. This approach has revolutionized several areas, including image generation, data augmentation and unsupervised learning.

    A GAN consists of two main components: the generator and the discriminator. The generator produces synthetic data, such as images, while the discriminator compares this data with real data. The generator aims to produce data that is indistinguishable from real data, while the discriminator endeavors to distinguish between real and generated data. This adversarial process continues until the generator produces very realistic data that the discriminator can no longer reliably distinguish from real data.

    During the training process of a GAN, the generator creates synthetic patterns, which are then evaluated by the discriminator. The discriminator provides feedback on the realism of the samples and the generator adjusts its parameters to improve the quality of its results. This iterative process is like a game of cat and mouse, where the generator and discriminator continuously improve in response to each other’s actions.

    GANs have numerous applications. In image processing, they can generate high-resolution images from low-resolution input, create realistic human faces and even convert images from one style to another, e.g. turning sketches into photorealistic images. In the field of video games, GANs can create realistic textures and environments. In addition, GANs are used in the medical field to create synthetic medical images for research and training purposes when real data is scarce.

    Despite their capabilities, adversarial networks face some challenges. Training GANs can be difficult due to the delicate balance between the generator and the discriminator. If one network becomes too strong compared to the other, the training process can become unstable. In addition, GANs are known to suffer from mode collapse, where the generator only produces a limited number of samples and cannot capture the diversity of the real data distribution.

  • Algorithm

    A finite set of precise and well-defined instructions that describe a process or procedure for solving a problem or carrying out a specific task. These instructions are step-by-step and must be executed in a specific order to achieve the desired outcome. Algorithms are used in various fields, from mathematics and computer science to engineering and artificial intelligence, and can be expressed in different forms, such as flowcharts, pseudocode, or programming languages.

    Efficiency and clarity in the definition of an algorithm are essential to ensure its correct implementation and understanding. Algorithms are fundamental in computer science and many other disciplines because they provide a systematic method for tackling complex problems.

  • Algorithm

    An algorithm is a series of precisely defined instructions that are used to perform a specific task or solve a problem. In artificial intelligence (AI), algorithms are essential for processing data, learning from it and making decisions. There are different types of algorithms used in AI, each serving different purposes.

    Supervised learning algorithms are trained on labeled data to predict outcomes. Examples include linear regression and decision trees. Unsupervised learning algorithms work with unlabeled data to find hidden patterns. A typical example is K-Means clustering. Reinforcement learning algorithms learn by interacting with an environment and receiving feedback, such as Q-learning. Deep learning algorithms use neural networks with many layers for complex tasks such as image recognition. A well-known example of this are convolutional neural networks.

    The functioning of an AI algorithm usually involves several steps. First, data is collected, which is then pre-processed to clean it up and format it appropriately. The algorithm is then trained on this data to learn patterns and relationships. The performance of the model is evaluated by testing it on new data. Finally, the trained model is applied to make predictions or decisions based on new inputs.

    Algorithms have a wide range of applications. In healthcare, they help diagnose diseases by analyzing medical images. In finance, they are used to predict stock trends and detect fraudulent activity. In everyday life, algorithms power search engines, recommend products on e-commerce websites and enable voice assistants such as Siri and Alexa to understand and respond to queries.

    Despite their power, algorithms also pose a challenge. They can inherit biases from the data on which they have been trained, leading to unfair or unethical results. Ensuring the transparency and explainability of AI algorithms is crucial, especially in sensitive applications such as criminal justice or healthcare.

  • Artificial Neural Network (ANN)

    An Artificial Neural Network (ANN) is a computational model based on the way biological neural networks in the human brain process information. ANNs are used in artificial intelligence (AI) to recognize patterns, learn from data and make decisions. They consist of layers of interconnected nodes or neurons, where each connection has a weight that adjusts during the learning process.

    ANNs usually have an input layer, one or more hidden layers and an output layer. The input layer receives the initial data, which is then passed through the hidden layers where the actual processing and learning takes place. The output layer delivers the final result. The neurons in each layer are connected to the neurons in the subsequent layer and these connections carry weights that are adjusted during the learning process.

    The learning process in Artificial Neural Network involves adjusting the weights of these connections based on the error of the output compared to the expected result. This is often done using a method called backpropagation, which calculates the error contribution of each neuron and adjusts the weights to minimize the overall error.

    ANNs are particularly powerful in tasks such as image and speech recognition, where they can recognize patterns and make decisions based on complex, high-dimensional data. They are also used in applications such as language translation, medical diagnosis and even playing complex games such as chess and Go.

    Despite their capabilities, ANNs have some challenges to overcome. They require large amounts of data and computing power to train effectively. They can also be considered a “black box” as it is often difficult to understand how they arrive at their decisions. This lack of transparency can be a problem in critical applications where understanding the decision-making process is important.

  • Autonomous systems

    An autonomous system is able to perform tasks or make decisions without human intervention. These systems rely on advanced algorithms, machine learning and AI to operate independently, adapt to new situations and learn from their environment.

    Autonomous systems usually have several important functions and components. First, they use sensors to collect data about their environment. This data is then processed using algorithms that help the system to understand and interpret the environment. Machine learning models play a crucial role in enabling these systems to learn from their experiences and improve over time. Decision-making algorithms allow the system to choose the best course of action based on the information available.

    That systems have a wide range of applications in different industries. In transportation, vehicles, such as self-driving cars, use sensors, cameras and AI to navigate roads, avoid obstacles and transport passengers without human drivers. In manufacturing,  can take over complex tasks on production lines, increasing efficiency and reducing the need for human labor. In agriculture, drones and machines can monitor crops, apply fertilizer and harvest crops with minimal human intervention. In healthcare,  can assist with operations, care for patients and manage logistics in hospitals. Autonomous systems are also used in space exploration, where robots and rovers can explore distant planets and moons and perform tasks that would be dangerous or impossible for humans.

    Despite their potential, autonomous systems face a number of challenges. Ensuring safety and reliability is of paramount importance as these systems often operate in dynamic and unpredictable environments. Developing algorithms that can deal with all possible scenarios and make safe decisions is complex. There are also ethical and legal considerations, such as determining responsibility in the event of an accident involving an autonomous vehicle. In addition, public trust and acceptance of autonomous systems are crucial to their widespread adoption. People need to be confident that these systems will operate safely and effectively. There are also concerns about job displacement, as autonomous systems may take over tasks traditionally done by humans.

    The future of autonomous systems looks promising as advances in AI and machine learning ensure continuous improvements. As the technology develops, we can expect to see increasingly sophisticated and powerful autonomous systems in a variety of areas. Collaboration between researchers, industry and policy makers will be essential to overcome the challenges and ensure the safe and ethical use of that technologies.

B

  • Backpropagation

    It is an algorithm used in the training of neural networks. Its function is to adjust the network’s weights based on the difference between the predicted output and the desired output. This process is carried out in reverse through the network, calculating gradients and applying optimization techniques to reduce error and improve the network’s performance during training.

    Backpropagation is vital for training deep neural networks, allowing them to learn from data and improve their accuracy in tasks such as image recognition, language processing, and more.

  • Bagging

    Abbreviation for Bootstrap Aggregating, it is an ensemble technique in machine learning that integrates multiple models to increase stability and accuracy. First, multiple training data subsets are generated from the original dataset through sampling with replacement. This means that some examples may appear in several subsets, while others may not appear at all. Subsequently, a learning model is trained on each of these data subsets. These models can be of the same type, such as decision trees, but are trained with different data subsets.

    Once all models are trained, aggregated prediction is performed. For classification problems, predictions are obtained through majority voting among the models. For regression problems, predictions are averaged.

C

  • Capsule

    In the context of Capsule Networks, a capsule is a basic processing unit. Each capsule is designed to capture and represent a specific feature of an object in an image. The information is organized hierarchically, allowing for a more robust and precise representation of the relationships between features compared to conventional architectures.

D

  • Data Augmentation

    Also known as data augmentation, it is a technique used in machine learning to increase the size of the dataset by applying transformations to existing data. This is achieved by applying various transformations to the existing data, such as rotations, scaling, translations, cropping, and other changes. The goal of data augmentation is to improve the model’s generalization and performance by providing more variety in the training data, which helps prevent overfitting.

    Data augmentation is especially useful when there is a limited dataset available, as it allows for artificially expanding the dataset size, which can lead to better model performance and greater generalization ability.

E

  • Ensamble

    It is a technique in machine learning that improves predictive performance by combining multiple individual models. These models can be of the same type or different types. By merging the predictions of several models, ensemble methods can reduce bias and variance, resulting in a more robust and generalizable model. Additionally, it can mitigate the individual errors of each model. Common ensemble methods include bagging, boosting, and model voting combinations.

    The use of ensembles can lead to significant improvements in the accuracy and robustness of machine learning models, especially in situations where individual models have limitations or exhibit high variance.

F

  • Federated Learning

    Federated Learning is a technique for training machine learning models in which the model is trained in a distributed manner across multiple devices or servers containing local data, without the need to centralize this data. This technique is particularly useful for preserving data privacy and security, as sensitive data does not move from its original locations.

    These are the main steps in the federated learning process:

    1. Model Initialization: A machine learning model is initialized on a central server.
    2. Model Distribution: This initial model is distributed to several participating devices or servers (clients).
    3. Local Training: Each client trains a copy of the model with its local data. This step is performed independently on each client.
    4. Model Update: The parameters of the locally trained model are sent back to the central server, instead of sending the data.
    5. Aggregation: The central server aggregates (combines) the updates from the models received from all clients to improve the central model.
    6. Iteration: This process is repeated over several rounds, with the centralized model being redistributed to the clients, trained locally, and the updates aggregated.

G

  • Gaussian Mixture Model (GMM)

    A Gaussian Mixture Model (GMM) is a statistical technique used to model the distribution of data. Specifically, it is used to identify subpopulations within a dataset that are assumed to come from a combination of several Gaussian (or normal) distributions with different means and covariances.

    Here is a detailed explanation:

    1. Mixture Model: The GMM assumes that the data can be modeled as a mixture of several Gaussian distributions. Each component of the mixture is a multivariate normal distribution with its own mean and covariance matrix.
    2. Probability Density Function: The probability density function of the GMM is a weighted sum of the density functions of each Gaussian component. The mixture weights represent the probability that a data point comes from each Gaussian component.
    3. Parameter Estimation: The parameters of the GMM (means, covariance matrices, and mixture weights) are typically estimated using the Expectation-Maximization (EM) algorithm. This algorithm alternates between two steps:
      • Expectation (E) Step: Calculates the probability that each data point belongs to each Gaussian component, given the current parameters.
      • Maximization (M) Step: Updates the parameters of the Gaussian components to maximize the likelihood of the data, given the weights calculated in the E step.
    4. Class Assignment: After training the model, each data point can be assigned to the Gaussian component with the highest probability of generating it. This allows the GMM to be used for classification or unsupervised clustering tasks.

    The GMM is particularly useful in situations where the data do not fit well to a single normal distribution and can be better represented by a combination of multiple distributions. It is widely used in fields such as pattern recognition, computer vision, and bioinformatics, among others.

H

  • Hadoop

    Hadoop is an open-source software framework used for the storage and distributed processing of large volumes of data across computer clusters using simple programming models. It is especially known for its ability to manage big data efficiently and scalably. Hadoop was originally developed by Doug Cutting and Mike Cafarella and is maintained by the Apache Software Foundation.

    These are the main components and features of Hadoop:

    Hadoop Distributed File System (HDFS):

    • Distributed Storage: HDFS allows the storage of large files by dividing them into blocks and distributing them across multiple nodes in a cluster.
    • Replication: Data blocks are replicated across several nodes to ensure fault tolerance and high availability.
    • Data Access: Provides fast access to data through a distributed file system.

    MapReduce:

    • Programming Model: MapReduce is a programming model for the distributed processing of large data sets. It is based on two main functions: Map, which filters and sorts the data, and Reduce, which aggregates and summarizes the results.
    • Parallel Processing: Enables parallel processing of data across multiple nodes, improving processing efficiency and speed.

    YARN (Yet Another Resource Negotiator):

    • Resource Management: YARN manages cluster resources and schedules applications, allowing multiple applications to run simultaneously on the cluster.
    • Scalability: Facilitates Hadoop’s scalability by allowing better utilization of cluster resources.

    Hadoop Ecosystem: Hadoop has an ecosystem of tools and projects that complement its functionality, such as:

    • Hive: A data warehouse system that provides an SQL interface for querying data stored in HDFS.
    • Pig: A high-level language for processing data in Hadoop.
    • HBase: A distributed NoSQL database that runs on top of HDFS.
    • Spark: A fast data processing engine that can run on Hadoop and improves in-memory processing performance.
    • Sqoop: A tool for transferring data between Hadoop and relational databases.
    • Flume: A service for ingesting large amounts of streaming data into HDFS.

    In summary, Hadoop is a powerful and flexible platform for storing and processing big data, enabling organizations to manage and analyze large volumes of data efficiently.

  • Hard/Soft AI

    It refers to AI systems designed to perform specific tasks within a limited scope, while strong artificial intelligence refers to AI systems capable of reasoning, learning, and solving problems across multiple domains in a manner similar to humans. Weak AI focuses on specific tasks and does not aim to replicate human intelligence in its entirety, whereas strong AI aspires to reach or surpass the level of human intelligence in all its forms.

    In summary, while weak AI is practical and currently in use for specific tasks, strong AI represents a long-term goal that seeks to replicate or surpass general human intelligence.

J

  • Jaccard Index

    The Jaccard Index, also known as the Jaccard Coefficient, is a measure of similarity between two sets. It is used to compare the similarity and diversity of sample sets and is defined as the size of the intersection divided by the size of the union of the sets. This metric takes values between 0 and 1, where 0 indicates that the sets have no elements in common and 1 indicates that the sets are identical.

    Applications of the Jaccard Index

    1. Data Analysis and Data Mining: It is used to measure the similarity between data sets, such as user profiles, text documents, or genetic sequences.
    2. Recommendation Systems: It helps to find similarities between users or products to provide personalized recommendations.
    3. Computer Vision: It is used to evaluate the accuracy of image segmentations by comparing the pixels of the segmented areas.
    4. Natural Language Processing (NLP): Useful in comparing documents and text analysis to determine the similarity between different texts.

K

  • K-means

    K-means is a clustering algorithm used in the field of unsupervised learning. The goal of the algorithm is to group a dataset into K clusters (where K is a predefined number of clusters) based on the similarity of the observations to each other. The algorithm initially assigns K centroids randomly and then assigns each data point to the nearest centroid. The centroids are recalculated repeatedly, and the points are reassigned to the nearest centroids until convergence is reached. It is widely used in tasks such as customer segmentation, text classification, and image processing.

    Applications of the K-means Algorithm

    1. Customer Segmentation:Group customers based on common characteristics for targeted marketing.
    2. Image Compression:Reduce the number of colors in an image by representing similar colors with the same value.
    3. Document Clustering:Organize documents into groups based on their content and similarity.
    4. Pattern Analysis:Detect patterns in biometric data, such as fingerprints or genetic data.

L

  • Laplacian Eigenmap

    A technique used in the field of machine learning and data analysis, specifically for dimensionality reduction and non-linear embedding of data. This technique aims to discover the underlying geometric structure of a high-dimensional dataset and represent it in a lower-dimensional space. It is particularly useful when the data has a manifold structure that needs to be preserved in the lower-dimensional representation.

    Here is a more detailed explanation:

    1. Graph Construction: A graph is constructed to represent the relationships between the data points. The nodes of the graph are the data points, and the edges connect points that are close neighbors (according to a distance metric such as Euclidean).
    2. Laplacian Matrix: The Laplacian matrix of the graph is computed, which captures the structure of the graph and the relationships between the nodes. The Laplacian matrix is defined as L=D−WL = D – W, where DD is the diagonal degree matrix (the number of connections of each node) and WW is the weight matrix of the connections.
    3. Eigenvalue and Eigenvector Calculation: The eigenvalue problem for the Laplacian matrix is solved, obtaining the eigenvectors and eigenvalues. The eigenvectors corresponding to the smallest eigenvalues (excluding the smallest one, which is 0) are used for the new data representation.
    4. Embedding in Lower Dimension: The original data is projected into a lower-dimensional space using the selected eigenvectors. This new representation preserves the proximity relationships of the original data as much as possible.

    The result is a representation of the data in a lower-dimensional space that maintains the intrinsic geometric structure of the original dataset. This technique is useful in applications such as data visualization, preprocessing for machine learning models, and data exploration.

M

  • Memory Networks

    Memory Networks are a neural network architecture designed to handle tasks that require efficient management and access to large amounts of long-term memory data. They were introduced by the Facebook AI Research (FAIR) team and combine the capabilities of neural networks with an explicit memory component that can dynamically store and retrieve information.

    Applications of Memory Networks

    1. Natural Language Processing (NLP):
      • Question Answering: Where the network needs to remember and access facts stored in memory.
    2. Dialogue Systems:
      • Maintaining Context and Coherence: In long conversations by remembering past interactions.
    3. Reasoning Tasks:
      • Problem Solving: That requires the combination of multiple pieces of information stored in memory.

    In summary, Memory Networks are an advanced architecture that enhances the ability of neural networks to handle tasks requiring the manipulation and dynamic access to large amounts of long-term memory data.

N

  • Natural Language Generation (NLG)

    Natural Language Generation (NLG) is a subfield of artificial intelligence and natural language processing (NLP) that focuses on the creation of written or spoken text from structured data. The goal of NLG is to convert data into a format that is easily understandable for humans, producing texts that mimic the way humans communicate.

    Applications of NLG

    Automated Report Generation:

    Create financial reports, sales summaries, market analyses, etc., from raw data.

    Personalized Content:

    Generate personalized product descriptions, emails, recommendations, and more, based on user preferences and behaviors.

    Automated Journalism:

    Draft news articles and sports reports automatically from data and statistics.

    Virtual Assistants and Chatbots:

    Provide natural and relevant responses in conversations with users, enhancing the user experience.

    Education and Training:

    Create educational materials and simulations from educational and training data.

O

  • Object Detection

    Object Detection is a technique in the field of computer vision and artificial intelligence that involves identifying and locating instances of objects of one or several classes (such as people, cars, traffic signs, etc.) within an image or video. Unlike image classification, which only assigns a label to the entire image, object detection not only classifies the objects present but also determines their positions within the image using bounding boxes.

    Applications of Object Detection

    Security and Surveillance:

    • Intruder detection, identification of suspicious behaviors, and monitoring of restricted areas.

    Autonomous Vehicles:

    • Recognition of pedestrians, other vehicles, traffic signs, and obstacles for safe driving.

    Retail and E-commerce:

    • Inventory tracking, analysis of shopping behaviors, and improving customer experience through product detection.

    Medicine:

    • Analysis of medical images to detect anomalies, tumors, and other health conditions.

    Agriculture:

    • Monitoring crops and livestock, detecting pests, and optimizing agricultural practices.

P

  • Precision-Recall Curve

    It is a graph that shows the trade-off between precision and recall of a model according to a decision threshold. Precision refers to the proportion of correctly identified positive instances, while recall refers to the proportion of positive instances in the dataset that the model correctly identified. The precision-recall curve is useful for evaluating the performance of a classifier in problems with imbalanced classes.

    Applications

    Fraud Detection:

    • Evaluate and optimize models to identify fraudulent transactions with high precision and recall.

    Medical Diagnosis:

    • Evaluate classification models for diseases where it is crucial to minimize false negatives (not detecting a disease) and false positives (misdiagnosing).

    Spam Filtering:

    • Adjust models to detect unwanted emails (spam) while minimizing legitimate emails incorrectly marked as spam.

    Recommendation Systems:

    • Evaluate the effectiveness of recommendation algorithms to identify relevant items for users with high precision and recall.

    Object Detection in Images:

    • Optimize computer vision models to detect specific objects in images with high precision and recall.

Q

  • Q-Learning

    Q-Learning is a reinforcement learning algorithm used in artificial intelligence. It is used to learn an optimal policy for sequential decision-making in environments with rewards and penalties. Q-Learning uses a value function called the Q-function to estimate the expected value of an action in a given state. The algorithm iteratively adjusts the values of the Q-function while exploring the environment and learning to maximize long-term rewards.

    Advantages and Disadvantages

    Advantages:

    • Can handle problems with large state and action spaces.
    • Does not require a model of the environment (model-free).

    Disadvantages:

    • Can be inefficient in terms of convergence time.
    • Exploring large state spaces can be challenging without additional techniques.

    In summary, Q-Learning is a powerful reinforcement learning technique that enables agents to learn optimal behaviors through interaction with the environment, continuously updating their knowledge of the best actions to take in various situations.

R

  • Recurrent Neural Network (RNN)

    A Recurrent Neural Network (RNN) is a type of neural network designed to process sequential or temporal data. Unlike conventional neural networks, RNNs have feedback connections that allow them to maintain internal states and process sequences of variable length. This makes them suitable for tasks such as machine translation, speech recognition, text generation, and time series modeling. RNNs are used in a variety of applications across fields such as natural language processing, computer vision, and bioinformatics.

    Applications of RNNs

    Natural Language Processing (NLP):

    • Language modeling, text generation, machine translation, and sentiment analysis.

    Speech Recognition:

    • Speech-to-text transcription and command recognition systems.

    Time Series:

    • Financial data prediction, sales analysis, and weather forecasting.

    Music Generation:

    • Melody composition and sequence generation.

S

  • Self-Organizing Maps (SOM)

    A Self-Organizing Map (SOM) is a type of unsupervised neural network used for dimensionality reduction and visualization of multidimensional data. It was developed by Teuvo Kohonen in the 1980s, and hence it is also known as a Kohonen Map. SOMs map high-dimensional data into a lower-dimensional representation, usually one or two dimensions, preserving the topological relationships of the original data.

    Applications of SOMs

    Data Visualization:

    • Reduce the dimensionality of complex data to facilitate its visualization and understanding.

    Exploratory Data Analysis:

    • Discover structures and patterns in multidimensional datasets.

    Clustering:

    • Group data into clusters in an unsupervised manner.

    Pattern Recognition:

    • Identify and classify patterns in data, such as in image and signal analysis.

    Data Compression:

    • Reduce the size of data while maintaining its structure and main characteristics.

T

  • Temporal Difference Learning

    It is a reinforcement learning method that updates value estimates using the difference between successive estimates. Instead of waiting for a final reward, the algorithm continuously adjusts its value estimates based on immediate feedback from the environment. This approach enables faster and more efficient learning in environments where rewards are sparse or delayed.

U

  • Underfitting

    It is a phenomenon where a model is too simple for the data, resulting in poor performance on both training and test data. Underfitting can occur when a model is too restrictive or does not have enough parameters to capture the complexity of the data. This can lead to the model’s inability to generalize to new, unseen data.

V

  • Variance-Bias Tradeoff

    Fundamental concept in machine learning that describes the balance between a model’s ability to fit the data and its ability to generalize to new data. Variance refers to the model’s sensitivity to small fluctuations in the training data, while bias refers to the model’s tendency to make simplified assumptions about the data. Generally, there is a trade-off between reducing variance and reducing bias, and finding the right balance is crucial for the model’s performance.

W

  • Weight Initialization

    Process of setting initial values for the weights in a neural network before starting training. Proper weight initialization can improve model convergence and prevent issues like getting stuck in local minima. Common weight initialization techniques include random initialization, initialization with specific distributions such as normal or uniform, and initialization using methods like Xavier initialization or He initialization.

X

  • X-means

    Extension of the K-means clustering algorithm that automatically determines the optimal number of clusters in a dataset. Unlike K-means, which requires specifying the number of clusters beforehand, X-means uses criteria such as the Bayesian Information Criterion to automatically determine the optimal number of clusters during the clustering process.

Y

  • Yield Curve

    Graphical representation of interest rates at different maturities, usually for bonds from the same issuer and credit quality. The yield curve shows the relationship between yield (or interest rate) and the maturity period of the bonds, and is used by investors and analysts to assess financial market conditions, economic expectations, and monetary policies.

Z

  • Zero-Day Exploit

    A cyberattack that exploits a security vulnerability in software or an operating system before it is publicly known and a patch or solution can be developed. These attacks are usually difficult to detect and can cause significant damage to compromised systems and data. Mitigating zero-day exploit requires a rapid response and the implementation of proactive security measures.

Table of concepts

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