Artificial intelligence and data

Knowledge graph

A knowledge graph is a structured representation of knowledge as a network of entities and relationships, typically stored as triples, popularized by Google's 2012 search launch.

Knowledge graph embedding

Knowledge graph embedding is a machine learning method that represents knowledge graph entities and relations as low-dimensional vectors, used to predict missing links and classify triples.

Knowledge representation and reasoning

Knowledge representation and reasoning (KR) is the artificial intelligence field concerned with encoding knowledge in machine-interpretable form and computationally drawing conclusions, such as checking consistency or answering queries.

Knowledge tracing

Knowledge tracing is a machine learning method that predicts how likely a student is to answer future questions correctly, serving as the student model in intelligent tutoring systems.

Knowledge-based recommender system

A knowledge-based recommender system (KBR) recommends items by reasoning over explicit knowledge and the user's stated requirements, avoiding cold-start problems in infrequent purchases like financial services.

Knuth–Morris–Pratt algorithm

The Knuth–Morris–Pratt algorithm, or KMP, is a string matching algorithm that turns the search string into a finite state machine, published by Knuth, Morris, and Pratt in 1977.

Kolmogorov–Arnold Networks

Kolmogorov–Arnold Networks (KAN), proposed in 2024, are neural network architectures placing learnable univariate activation functions on edges instead of fixed node activations, offering interpretability and symbolic formulas.

Kornia

Kornia is an open source differentiable computer vision library for PyTorch, offering image processing, geometry, and augmentation operators usable inside neural networks and loss functions.

KServe

KServe, formerly KFServing, is an open-source platform that deploys, scales, and routes machine learning inference workloads on Kubernetes, developed by Google, IBM, Bloomberg, NVIDIA, and Seldon in 2019.

ksqlDB

ksqlDB (formerly KSQL) is the streaming SQL database of Confluent, part of IBM since 2026, built on Kafka Streams under the Confluent Community License; it now ships only in Confluent products, with Flink recommended for new workloads.

Kubeflow

Kubeflow is an open source, Kubernetes-native platform of modular projects (Pipelines, Trainer, Katib, KServe) for data and AI workloads, started by Google in 2017 from TensorFlow Extended and graduated from CNCF in 2026.

Kuratowski's theorem

Kuratowski's theorem, or Kuratowski reduction theorem, characterizes planar graphs: a graph is planar if and only if it contains no subdivision of K5 or K3,3.

Kyvos Insights

Kyvos Insights: Los Gatos, California company whose Kyvos semantic layer and Smart OLAP platform serve enterprise BI and AI; emerged from stealth in June 2015 with OLAP-on-Hadoop technology.

L'Année philologique

L'Année philologique (APh Online) is the international reference bibliography of classical studies, indexing more than 1,000 journals on ancient Greece and Rome from 1928 onward.

Label distribution learning

Label distribution learning (LDL) is a machine learning paradigm, proposed by Xin Geng in 2016, that predicts a distribution of description degrees over all labels rather than a single label.

Label propagation algorithm

Label propagation is a graph algorithm in which nodes repeatedly adopt the most common label among their neighbors, used for community detection and semi-supervised classification.

Label Studio

Label Studio is an open-source data labeling platform developed by HumanSignal that handles images, video, text, audio, and time series from a single configurable editor, creating annotated training datasets for machine learning.

Labeled Faces in the Wild

Labeled Faces in the Wild (LFW) is a public database of 13,233 labeled face photographs of 5,749 people, published in 2007 by University of Massachusetts researchers for face recognition research.

LabelMe

LabelMe is an MIT web tool and database for annotating objects in images for recognition research, and an open-source Python desktop application, inspired by it, for building training datasets.

Lagrange multiplier

A Lagrange multiplier, also called a Lagrangian multiplier, is a scalar introduced for each constraint to find a function's constrained extrema, named after Joseph-Louis Lagrange, who used the idea in his 1788 Méchanique analitique.

lakeFS

lakeFS is an open-source data version control system, "Git for data," by Treeverse (founded 2020). It adds zero-copy branching, commits, merges, and rollback to S3, Azure, and GCS data lakes, licensed under BSL 1.1.

Lakehouse architecture

Lakehouse architecture is a data management design that adds database features like ACID transactions to low-cost cloud object storage in open formats, serving analytics, machine learning, and streaming.

Lakehouse: A New Generation of Open Platforms (paper)

CIDR 2021 paper by Armbrust, Ghodsi, Xin, and Zaharia defining the lakehouse: warehouse features such as ACID transactions and SQL performance over open Parquet data lakes via a transactional metadata layer like Delta Lake.

Lakekeeper

Lakekeeper is an open-source (Apache 2.0) Apache Iceberg REST Catalog written in Rust by Vakamo, providing access control via OpenFGA/Cedar, vended credentials for S3, ADLS, GCS, audit, and a Lakekeeper+ commercial edition.

Lal Bihari (लाल बिहारी)

Lal Bihari, known as Lal Bihari Mritak, is an Indian farmer from Uttar Pradesh declared dead in 1976 who spent 18 years proving he was alive.

Lambda architecture

Lambda architecture is a data-processing architecture, originated by Nathan Marz, that runs batch and streaming pipelines side by side and merges their results at query time.

LaMDA

LaMDA (Language Model for Dialogue Applications) is a family of Transformer-based language models specialized for open-ended dialogue, developed by Google, announced in 2021, and later used to power Bard.

LanceDB

LanceDB is an open-source, embedded retrieval database built on the Lance columnar format, designed for vector search over multimodal AI data such as embeddings, text, images, video, and audio.

Language model

A language model, or language modeling, is a probability distribution over token sequences trained to predict the next token, the basis of systems like GPT-4.