Technologies
Each entry explains a technology, the problems it solves and its connections.
Bolt-action repeating rifle
Late 19th century: magazine-fed bolt-action rifles developed and became widespread · matureMilitaryA rifle with a manually operated bolt and a magazine that feeds successive rounds; here, “repeating” does not mean automatic fire.
Metallic cartridges
Developed in the mid-19th century; conversion applications around 1866 are the reference point verified in this review · matureMaterials · MilitaryMetallic cases hold ammunition components together and help seal breech-loading mechanisms, making them an important part of modern firearm systems.
Hand cannon
14th century: surviving artifacts or written records in both China and Europe · replacedMilitaryAn early, small metal firearm held by a person and ignited with an external flame, without a complete ignition lock of the kind found on a matchlock.
Reinforced concrete
Developed from reinforced products into structural systems in the mid-to-late 19th century · matureIndustry · MaterialsConcrete incorporates reinforcing elements such as steel bars, which work together with it to improve tensile and flexural performance.
Limestone calcined clay cement
2009–2012: research on ternary systems; international technical validation began in 2014 · emergingIndustry · MaterialsCombines clinker, calcined clay, limestone and gypsum, using synergistic hydration to reduce the clinker content of cement.
Rifling
Late 15th century: the technology was already present in German regions · matureIndustry · MilitaryRifling inside the barrel spins a projectile to improve its stability in flight; it is a separate aspect of firearm technology from the ignition system.
Paper cartridge
Origins remain to be verified; the artifacts confirmed in this review date to no later than 1859 · replacedMilitaryA unit that uses paper to combine some ammunition components in advance for easier transport and use, with a structure distinct from a metallic cartridge case.
Matchlock firearm
Mid-to-late 15th century: development of matchlock mechanisms in Europe · replacedMilitaryA mechanical mechanism controls a burning match for ignition, making it easier to coordinate holding the firearm and firing it.
Percussion ignition
1807: Forsyth's percussion mechanism patent marks a definite milestone · replacedMilitaryInitiates a primer through mechanical impact, marking an important shift from spark ignition toward the ignition systems of modern ammunition.
Semi-automatic rifles
Late 19th to early 20th century: early self-loading rifles appeared · matureMilitaryUses energy from firing to complete the loading cycle automatically, while firing only one round for each pull of the trigger.
Cement rotary kiln firing
Gradually adopted in industrial cement production in the late 19th century · matureEnergy · Industry · MaterialsA slowly rotating, inclined kiln moves and heats material, enabling continuous production of cement clinker.
Minié ball
1840s: development of the Minié ball, with a clearly documented milestone around 1848 · replacedMilitaryA projectile that changes its fit during firing eases the conflict between convenient loading and effective rifling engagement in muzzleloading rifles.
Percussion rifle-musket
Mid-19th century: an important stage in military rifled muzzleloaders · replacedMilitaryA muzzleloading long gun combining percussion-cap ignition, rifling and a suitable projectile, with the Pattern 1853 Enfield as a typical example.
Assault rifles
1940s: designs such as the StG44 gave the modern assault rifle category a clear form · matureMilitaryA category of automatic rifle that balances rifle use with the need for automatic fire at close range, typically using intermediate cartridges and offering selective fire.
Automatic rifle
Early 20th century: development of rifles capable of automatic fire, with the BAR as a representative example · matureMilitaryA category of rifles capable of automatic loading and continuous fire; the meaning of "automatic rifle" must be distinguished across historical contexts.
Lime burning
Archaeological evidence of lime burning dates to around 10000 BCE · matureEnergy · Industry · MaterialsControlled heating of calcareous rock produces reactive lime, transforming natural rock into a workable raw material for binders.
Milling
Early 19th century: specialized cutting machinery developed by Hall and others · matureIndustryA machining method that removes material with a rotating cutter, contributing to consistency of mechanical parts and the machining of complex surfaces.
Interchangeable-parts manufacture
Developed in the early 19th century; Hall's project of 1819–1822 is a verified example · matureIndustryUses dimensional consistency and process control to make parts of the same type interchangeable, reducing the burden of individual fitting and maintenance.
Wheellock firearm
Around 1500: wheellock mechanisms appear in Europe · replacedMilitaryA spring-driven wheel strikes sparks against an ignition material, reducing dependence on a continuously burning match.
Lever-action repeating rifle
1860s: clearly documented examples in the Henry and Winchester lines · matureMilitaryA manually operated lever mechanism works with an ammunition-feeding system to enable repeated firing, forming one parallel approach to manually operated repeating firearms.
Pozzolanic binder technology
Hydraulic applications combining lime and volcanic ash existed by at least the 1st century BCE · matureIndustry · MaterialsUses reactions between reactive siliceous and aluminous materials and calcium-bearing systems to form binding products; both ancient natural volcanic ash and some modern activated clays can participate in this mechanism.
Gunpowder (black powder)
Approximately the 9th–11th centuries: from early Chinese accounts to the Wujing Zongyao (《武经总要》) · matureMaterials · MilitaryThe chemical energy source for early firearms, also used in engineering blasting; this entry covers black powder rather than later smokeless propellants.
Artificial intelligence
Named in the 1955 Dartmouth proposal; the research project took place in 1956 · matureInformation · Mathematics and MethodologyA set of reusable methods and system capabilities for learning, reasoning, perception, and goal-directed action through computational systems.
Artificial neural networks
The 1943 McCulloch–Pitts model of a logical neuron is an early reference point · matureInformation · Mathematics and MethodologyInterconnected artificial computational units use their connection structure and parameters to represent transformations from inputs to outputs.
Backpropagation
Earlier work on differentiation and training preceded it; a 1986 paper advanced representation learning in multilayer networks · matureInformation · Mathematics and MethodologyA method for computing parameter gradients in differentiable networks by applying the chain rule to propagate derivatives from the output toward earlier layers.
Bayesian networks
Developed into a systematic approach in the 1980s; a 1986 paper and a 1988 book are representative works · matureInformation · Mathematics and MethodologyA method that represents dependencies between variables using a directed acyclic graph and conditional probabilities, and updates beliefs after observing evidence.
Tuhuoqiang
1259: written record of the Shouchun tuhuoqiang · replacedMilitaryA bamboo-tube firearm described in Southern Song records as discharging a zike (子窠), illustrating a transitional form in the development of tubular firearms toward projectile firing.
Fire lance (early flame-projecting tubular firearm)
By 1132: Chinese texts record the use of fire lances · replacedMilitaryAn early firearm that projected flame from a tubular container, providing an important reference point for understanding technologies that preceded guns and cannon.
Binary numeral system
Developed in the 17th century; used in electronic computing in the 20th century · matureIndustry · InformationA numeral system that uses only 0 and 1 to represent values and states, providing a common representation for reliable digital switching and computer encoding.
Boolean algebra
1847–1937 · matureIndustry · InformationA mathematical system that represents truth values and logical operations with algebraic rules, providing a formal method for designing combinations of logic gates and switching circuits.
Breech-loading firearm technology
Earlier origins; a Ferguson flintlock breechloader from around 1780 was confirmed in this review · matureMilitaryAmmunition is loaded through the rear of the barrel, with breech locking and gas sealing among the central challenges.
Central processing unit
1945–1951 · matureIndustry · InformationThe core computer component that executes instructions, performs arithmetic and logical operations, and coordinates registers, memory, and input/output.
Charcoal production
Known in antiquity; became a metallurgical fuel before and around modern industrialization · matureEnergy · Industry · MaterialsHeating wood with no oxygen or limited oxygen to obtain a solid fuel with a higher fixed-carbon content and better suitability for high-temperature combustion.
CMOS
1963–1975 · matureIndustry · InformationA circuit technology that uses complementary p-channel and n-channel MOSFETs to form logic networks with almost no steady-state DC power consumption.
Control of fire
Archaeological evidence of controlled fire use appears from about 1 million years ago · matureEnergy · MaterialsIgniting, sustaining, regulating, and using flames turns combustion in the environment into a repeatable source of heat.
Convolutional neural networks
Research began earlier; the 1998 document-recognition paper serves as this entry’s engineering reference point · matureInformation · Mathematics and MethodologyNeural networks that use local connections and weight sharing to process spatial or sequential structure.
Cement
Hydraulic binders existed in ancient Rome; modern industrial cement developed in the 18th–19th centuries · matureIndustry · MaterialsA binder that reacts with water to form hardened products, joining particles or components into a whole; Portland cement is one type.
Deep learning
Research on training deep models in 2006 and large-scale vision applications in 2012 are important development milestones · matureInformation · Mathematics and MethodologyA machine-learning approach that progressively extracts and combines features through multiple layers of trainable representations.
Deep reinforcement learning
The 2015 DQN paper is a representative reference point for decision-making from pixel inputs; research began earlier · matureInformation · Mathematics and MethodologyReinforcement learning methods that use deep networks to represent values, policies, or models of the environment.
Diffusion generative models
2015: the diffusion-based generative approach; 2020: representative DDPM image-generation results · matureInformation · Mathematics and MethodologyGenerative models that recover data structure from noise by learning a stepwise denoising or reverse-diffusion process.
Digital logic circuits
1937–1948 · matureIndustry · InformationA system of circuits that processes information using discrete signals and logic gates, implementing binary representation and Boolean rules as hardware that can be combined.
Electric generators
Developed during the 19th century from magneto-electric machines into practical self-excited generators · matureEnergy · IndustryA device that converts rotational mechanical work into electrical energy through electromagnetic induction.
Electric power systems and grids
Central power stations appeared in 1882; scalable AC transmission systems took shape in the late 19th century · matureEnergy · Industry · Information · TransportA system for supplying and consuming electrical energy that combines generation, voltage transformation, transmission, distribution, protection, and dispatch.
Electromagnetic induction
Discovered in 1831; self-excited generators developed in the late 19th century · matureEnergy · Information · Mathematics and MethodologyThe physical principle by which changing magnetic flux induces an electromotive force in a conductor, linking mechanical motion with electric current.
Expert systems
Knowledge-based systems such as DENDRAL developed in the 1960s · matureInformation · Mathematics and MethodologySystems that organize domain knowledge and reasoning processes to provide analysis or advice within a limited problem area.
Flintlock firearms
Early 17th century: the mature French flintlock mechanism; other spark-striking designs preceded it · replacedMilitaryIgnites the charge with sparks produced by flint striking steel; mature European mechanisms and late-Ming zisheng huochong require separate documentation.
Concrete
Mature applications existed in ancient Rome; modern cement concrete developed widely in the 19th century · matureIndustry · MaterialsA composite material made by mixing and shaping a binder, fine and coarse aggregates, and water, then allowing it to harden for use in structures.
Caplock firearm
First half of the 19th century: percussion-cap ignition developed and entered military use · replacedMilitaryReplaced flint-and-steel ignition with a percussion cap, representing the most direct change in firearms after the flintlock.
Portland cement
1824: Portland cement patent; key advances in clinker production in the 1840s · matureIndustry · MaterialsA hydraulic binder made by firing a prepared mix of calcareous and siliceous/aluminous raw materials into silicate clinker, then grinding it with gypsum and other materials.
Lime mortar
Used in antiquity; the sources in this review confirm established lime-binding practices in ancient Rome · matureIndustry · MaterialsA workable masonry or repair material made from lime, sand, and water; traditional air-hardening formulations harden mainly through carbonation.
Single-shot breech-loading rifle
Mid-to-late 19th century: widespread use of single-shot breech-loading rifles with metallic cartridges · replacedMilitaryA rifle loaded from the rear with one round at a time; this entry focuses on 19th-century military types using metallic cartridges.
Heuristic search
Earlier explorations existed; the 1968 A* paper serves as this entry’s verified reference point · matureInformation · Mathematics and MethodologyA method that uses problem-specific estimates to guide the search order and reduce the number of candidate states explored.
Reinforcement learning from human feedback
2017: research on rewards learned from preferences; 2022: application to language-model instruction following · matureInformation · Mathematics and MethodologyA method that learns a reward signal from human evaluations or preferences, then uses reinforcement learning to adjust model behavior.
Integrated circuits
1958–1961 · matureIndustry · InformationAn electronic circuit with multiple transistors, resistors, capacitors, and interconnections manufactured on a single semiconductor substrate.
Junction transistor
1948–1952 · matureIndustry · InformationA three-terminal bipolar transistor structure that uses p-n junctions and carrier injection through the base region for amplification and switching.
Language-model agents
Represented by the 2022 ReAct preprint and 2023 conference paper; the concept of agents predates them · emergingInformation · Mathematics and MethodologyTask-execution systems that combine language models with tool use, environmental feedback, and multistep decision-making.
Large language models
Language models and pretraining existed earlier; the 2020 GPT-3 paper is a representative milestone in scaling · matureInformation · Mathematics and MethodologyModels trained on large-scale language data that can predict, generate and process language sequences.
Large-scale integration
1967–1972 · matureIndustry · InformationA stage of technology and scale of design that integrates hundreds to thousands of transistors and their interconnections into a single integrated circuit.
Machine learning
Samuel's 1959 paper on learning in a board game is an early representative example, not the sole origin · matureInformation · Mathematics and MethodologyMethods that adjust a model using data or experience from interaction to improve a system's performance on a target task.
Magnetic-core memory
1949–1955 · matureIndustry · InformationRandom-access memory that stores binary bits in tiny magnetic cores whose magnetization can be reversed, using wire windings for selection, reading, and writing.
Mercury delay-line memory
1947–1951 · matureIndustry · InformationSerial memory that transmits pulses as sound waves through mercury-filled tubes and recirculates them for reading and writing.
Metal smelting
Early metal smelting appeared from around 5000 BCE; large-scale furnace workshops emerged in the Bronze Age · matureEnergy · Industry · MaterialsExtracts metals from ores using controlled high temperatures and a reducing environment, then produces usable materials through melting, casting, or forging.
Microprocessor
1971–1972 · matureIndustry · InformationA processor device that integrates the main functions of a central processing unit onto a single chip that can be packaged as one device.
Microprogramming
1951–1960 · matureIndustry · InformationA method of implementing machine-instruction control logic through sequences of microinstructions held in a control store.
MOS integrated circuit
1964–1970 · matureIndustry · InformationAn integrated-circuit approach that uses MOSFETs as its basic devices to implement logic or memory functions on a single chip.
MOSFET
1959–1960 · matureIndustry · InformationA field-effect transistor that uses the electric field from an insulated gate to control conduction in a semiconductor channel, serving as the basic switching device in MOS integrated circuits.
Perceptron
Rosenblatt's 1958 paper; this entry focuses on the single-layer classification model · matureInformation · Mathematics and MethodologyAn early neural learning model that classifies inputs using a weighted sum and a threshold, and adjusts weights using misclassified examples.
Semiconductor photolithography
1955–1960 · matureIndustry · InformationUses photomasks and photosensitive materials to transfer circuit patterns onto wafer surfaces, enabling repeatable manufacture of semiconductor devices.
Photovoltaic cell
1839: discovery of the photovoltaic effect; 1954: silicon photovoltaic cells became practical for power generation · matureEnergy · Industry · MaterialsA device that uses the photovoltaic effect in semiconductors to convert solar radiation directly into direct-current electricity.
Planar process
1959–1961 · matureIndustry · InformationA semiconductor fabrication process that retains a protective silicon dioxide layer on the silicon surface and uses masks to form devices and interconnections.
Point-contact transistor
1947–1948 · matureIndustry · InformationAn early three-terminal solid-state device for amplification and switching that uses two closely spaced metal contacts to control current in a semiconductor.
Read-only memory
1965–1971 · matureIndustry · InformationNonvolatile semiconductor memory whose contents are set during manufacturing or programming and primarily read during operation.
Reinforcement learning
Its historical roots are earlier; the 1992 Q-learning paper is the representative milestone used in this entry · matureInformation · Mathematics and MethodologyA method for optimizing long-term cumulative return by interacting with an environment, receiving rewards and improving an action policy.
Retrieval-augmented generation
The paper naming RAG appeared in 2020; research combining retrieval and generation predates it · matureInformation · Mathematics and MethodologyA method that introduces content retrieved from external materials during generation to supplement knowledge stored in the model's parameters.
Semiconductor memory
1960–1971 · matureIndustry · InformationAn umbrella term for memory that integrates storage cells, decoding, and read/write circuits on a semiconductor chip, including approaches such as RAM and ROM.
Silicon-gate process
1968–1971 · matureIndustry · InformationA manufacturing process that uses polysilicon MOS gates and self-aligned structures to improve device speed, dimensions, and interconnection capabilities.
Silicon transistor
1954–1961 · matureIndustry · InformationA transistor made from high-purity silicon with controlled doping, improving on germanium devices in temperature stability, leakage current and suitability for mass production.
Steam engines
Improved in the 18th century and adopted in factories, mines, and transport · replacedEnergy · Industry · TransportA heat engine that converts the pressure of steam produced by a boiler into reciprocating or rotary mechanical work.
Stored-program computer
1948–1951 · matureIndustry · InformationA general-purpose computer architecture that stores both instructions and data in readable and writable memory and executes instruction sequences automatically.
Support vector machines
The 1995 support-vector networks paper is an important reference point for the mature method · matureInformation · Mathematics and MethodologyA supervised learning method that constructs decision boundaries using a margin criterion and can handle nonlinear data through kernel methods.
Symbolic artificial intelligence
Took shape gradually in the 1950s; a 1976 treatment of symbols and search offers a representative synthesis · matureInformation · Mathematics and MethodologyAn approach to artificial intelligence that represents knowledge and solves problems using explicit symbols, rules and reasoning operations.
Transformer
The architecture was proposed in Attention Is All You Need in 2017 · matureInformation · Mathematics and MethodologyA neural network architecture that organizes sequence information processing through attention mechanisms and feed-forward transformations.
Transistor-transistor logic
1961–1964 · matureIndustry · InformationAn integrated-circuit logic family in which bipolar transistors perform both input logic and output driving.
Transistorized computer
1953–1961 · matureIndustry · InformationA general-purpose computer system that uses discrete transistors in place of its principal vacuum-tube logic and amplifiers.
Vacuum tube
1904–1906 · matureIndustry · InformationAn electronic device that uses the movement of electrons in a vacuum for rectification, amplification or switching, and was the main active device in early electronic computers.