3,135 articles
Log-structured merge-tree
The log-structured merge-tree (LSM-tree) is a disk-based data structure that batches and cascades index updates, introduced in a 1996 paper by Patrick O'Neil and colleagues and now the storage engine behind RocksDB, Cassandra, and Bigtable.
Logical data warehouse
Logical data warehouse (LDW, virtual data warehouse): a Gartner-coined analytical architecture in which a semantic/virtualization layer over a traditional EDW integrates diverse sources via reusable metadata without physical consolidation; supports AI and RAG workflows.
Logstash
Logstash is Elastic's open source server-side data processing pipeline, the L in the ELK stack, started by Jordan Sissel in 2009. It uses input, filter, and output plugin stages with 200+ plugins to ingest, transform, and ship events.
Long short-term memory
Long short-term memory (LSTM) is a recurrent neural network architecture, introduced by Sepp Hochreiter and Jürgen Schmidhuber in 1997, that stores information over long time spans using gated memory cells.
Longest common subsequence
The longest common subsequence (LCS) problem asks for the longest sequence formed from two sequences by deleting symbols, solved by dynamic programming and used in file comparison and biology.
Longest palindromic substring
The longest palindromic substring problem asks, for a given string, for its longest contiguous substring that reads the same forwards and backwards, solvable in O(n) time by Manacher's 1975 algorithm.
Looker Studio
Looker Studio is Google's free data visualization and dashboarding tool, originally Data Studio (2016), renamed Looker Studio in October 2022 with a $9 Pro tier, and renamed back to Data Studio in April 2026.
LookML
LookML (Looker Modeling Language) is Looker's proprietary semantic modeling language, created by Lloyd Tabb around 2012, defining dimensions, measures, explores, and views; Google opened it partly via the BigQuery-only Open SQL Interface in 2024.
Lookup table
A lookup table (LUT) is a precomputed array of values a program retrieves by index instead of computing them at run time, trading memory for speed.
LoRA (machine learning)
LoRA (Low-Rank Adaptation) is a parameter-efficient fine-tuning technique for large language models in which frozen pre-trained weights are supplemented with small trainable low-rank matrices, introduced at Microsoft in June 2021.
Loss functions for classification
Loss functions for classification are the penalties a learning algorithm minimizes when fitting a classifier, with surrogates like log loss, hinge loss, and cross-entropy used in practice.
Loss landscape analysis in deep learning
Loss landscape analysis studies the geometry of the high-dimensional, nonconvex loss surface that neural network training minimizes, including minima, saddle points, and low-loss paths between solutions.
Lossless compression
Lossless compression, also called reversible compression or lossless encoding, is a completely reversible data reduction process used where exact data matters, such as text, executables, and scientific measurements.
Lottery ticket hypothesis
The lottery ticket hypothesis is a 2018 deep learning conjecture by Jonathan Frankle and Michael Carbin: dense random networks contain sparse winning-ticket subnetworks that train to full accuracy alone.
Louvain method
The Louvain method is a greedy heuristic algorithm for detecting communities in large graphs by maximizing modularity, proposed by Blondel, Guillaume, Lambiotte, and Lefebvre in 2008.
Lucas–Kanade method
The Lucas–Kanade method is a widely used computer vision technique for image alignment and optical flow, introduced in 1981 by Bruce Lucas and Takeo Kanade of Carnegie-Mellon University.
Luhn algorithm
The Luhn algorithm, also called the mod 10 or modulus 10 algorithm, is a checksum formula created by Hans Peter Luhn at IBM in 1954.
Lyapunov optimization
Lyapunov optimization is an online control framework for stochastic networks that stabilizes queues while optimizing time-average objectives, making greedy per-slot decisions from current queue states alone.
LZ77 and LZ78
LZ77 and LZ78, also known as Lempel–Ziv coding, are lossless data-compression algorithms published by Jacob Ziv and Abraham Lempel in 1977 and 1978, ancestors of most compressors today.
Machine learning
Machine learning is the branch of computer science concerned with building computers that improve automatically through experience, drawing on statistics and spanning supervised, unsupervised, and reinforcement learning.
Machine Learning Algorithms
Machine learning algorithms: procedures by which computer systems learn from data to improve accuracy, grouped into supervised, unsupervised, and reinforcement learning; examples include regression, random forests, SVMs, neural networks, and XGBoost.
Machine learning engineer
Machine learning engineer (ML engineer): software professional who designs, trains, deploys, and maintains machine learning models in production, distinct from data scientist and AI engineer; role emerged pre-2011, defined in frameworks like UK GDD, with median US salary near $165,000.
Machine learning for Earth observation
Machine learning for Earth observation is the use of deep neural networks to turn satellite and airborne imagery into products like land cover maps and flood extents.
Machine learning in materials science
Machine learning in materials science, often called materials informatics, uses models trained on materials data to predict properties, screen candidates, and guide synthesis and processing.
Machine-readable passport
A machine-readable passport (MRP) is a passport whose biodata page carries a scannable Machine Readable Zone, defined by ICAO Doc 9303 and required of all countries since 2010.
Mage (software)
Mage (Mage AI), founded 2021 by Tommy Dang, is a data pipeline platform combining notebook-style pipeline building, orchestration, integration, deployment, and AI features; distinct from Mage.space and the MAGE game framework. Open source (Apache-2.0), with a commercial Mage Pro edition and a $12M Series A in 2026.
Malaysian identity card
The Malaysian identity card, issued as MyKad, is the compulsory smart identity card for Malaysian citizens aged 12 and above, issued by the National Registration Department.
Malaysian passport
The Malaysian passport (Pasport Malaysia) is the travel document issued to Malaysian citizens by the Immigration Department, and the world's first electronic passport, launched in 1998.
Malloy (query language)
Malloy is an open-source semantic modeling and query language created by Lloyd Tabb (Looker, LookML) that compiles to SQL for BigQuery, Snowflake, DuckDB, Postgres, and other engines, with symmetric aggregates and reusable models.
Mamdani fuzzy inference
Mamdani fuzzy inference is a method that maps numeric inputs to outputs through fuzzy if-then rules, introduced by Mamdani and Assilian in 1975 for steam-engine control.