All articles A–Z

Differential gene expression analysis

Differential gene expression analysis, also called differential expression analysis, is a bioinformatics method comparing gene expression between conditions, typically RNA-seq, to identify significantly up- or down-regulated genes.

Differential geometry

Differential geometry, also known as differential geometry and topology, is the branch of geometry that studies curves and surfaces by analysis, centered on differentiable manifolds and supplying the language of general relativity.

Differential GPS

Differential GPS, also known as DGNSS, is an augmentation technique that improves GPS accuracy to 3 to 5 meters by broadcasting corrections from a surveyed reference station.

Differential hardening

Differential hardening is a heat treatment that makes a blade's edge harder than its body, best known from Japanese swordsmithing, where it produces the hamon temper line.

Differential imaging

Differential imaging is a family of high-contrast astronomical techniques that builds a model of a star's light from reference images and subtracts it, revealing faint exoplanets and disks near the star.

Differential inclusion

A differential inclusion is a continuous-time evolution law x'(t) ∈ F(t, x(t)), generalizing an ordinary differential equation by allowing multiple velocities at each state, with origins in control theory.

Differential interference contrast microscopy

Differential interference contrast (DIC) microscopy is an optical beam-shearing interference technique that converts refractive index gradients in transparent specimens into visible intensity differences, imaging unstained living cells.

Differential interferometric SAR

Differential interferometric SAR (DInSAR) is a radar remote-sensing technique comparing SAR images from repeated satellite passes to measure ground deformation from earthquakes, volcanoes, and subsidence with millimeter precision.

Differential interferometry

Differential interferometry (DInSAR) is a satellite radar remote-sensing method that compares SAR images acquired at different times to measure millimeter-scale ground deformation from earthquakes, volcanoes, landslides, and subsidence.

Differential item functioning

Differential item functioning (DIF) is a psychometric method that flags test items behaving differently for different groups, such as demographic subpopulations, after examinees are matched on ability.

Differential kinematics

Differential kinematics is the branch of robot kinematics describing how joint velocities map to the end effector's instantaneous linear and angular velocities, through the Jacobian matrix.

Differential learning

Differential learning is a motor learning method in which athletes practice a movement in many varied, non-repeated forms without corrective feedback, used in sports training and rehabilitation.

Differential methylation analysis

Differential methylation analysis is a bioinformatics method that compares DNA methylation levels between sample groups, identifying differentially methylated CpG sites and regions in EWAS and cancer studies.

Differential mobility analyzer

A differential mobility analyzer is an aerosol instrument that classifies charged particles by electrical mobility, serving as the central element in systems measuring nanoparticle size distributions.

Differential mobility spectrometry

Differential mobility spectrometry (DMS), also known as FAIMS, is an atmospheric-pressure ion filtering technique used before mass spectrometers, separating ions by how their mobility changes with electric field.

Differential network analysis

Differential network analysis is a bioinformatics method that compares gene or protein interaction networks between conditions, finding rewired interactions rather than changes in single molecules.

Differential of a function

The differential of a function is the main, linear part of its change when the input changes, dy = f′(x) dx; the idea goes back to Leibniz in 1684.

Differential operator

A differential operator, also called a derivative operator, is an operator that maps a function to a function built from its derivatives. The basic example is D = d/dx, whose inverse denotes integration.

Differential optical absorption spectroscopy

Differential optical absorption spectroscopy (DOAS) is a spectroscopic technique that retrieves atmospheric trace-gas concentrations, such as NO2, SO2, and ozone, from UV and visible absorption spectra.

Differential pair

A differential pair is an amplifier stage in which two matched transistors share a single tail current and respond to the difference between their input voltages.

Differential phase contrast imaging

Differential phase contrast (DPC) imaging is an electron microscopy and X-ray technique that maps electric and magnetic fields in materials, reaching atomic resolution in modern instruments.

Oct 22, 2026

Differential phase-contrast scanning transmission electron microscopy

Differential phase-contrast scanning transmission electron microscopy (DPC STEM) is an electron microscopy technique that maps electric and magnetic fields inside a specimen by measuring how a focused electron probe is deflected.

Differential privacy

Differential privacy is a mathematical definition of privacy for data analysis, formalized in 2006, guaranteeing that results barely change whether or not any one person's data is included.

Differential privacy SGD

Differentially private stochastic gradient descent (DP-SGD) is a privacy-preserving variant of stochastic gradient descent, introduced by Abadi et al. in 2016 and the standard method for private neural network training.

Differential protection

Differential protection is a unit-protection technique in electrical power engineering that compares currents entering and leaving a zone, such as a transformer or busbar, and trips when the difference exceeds a threshold.

Differential pulse anodic stripping voltammetry

Differential pulse anodic stripping voltammetry (DPASV) is an electroanalytical technique that preconcentrates metal ions on an electrode to measure trace heavy metals at sub-ppb levels.

Differential pulse polarography

Differential pulse polarography (DPP) is a sensitive voltammetric analytical technique that superimposes constant-height potential pulses on a rising voltage ramp applied to a dropping mercury electrode.

Differential pulse voltammetry

Differential pulse voltammetry (DPV) is an electroanalytical technique applying small potential pulses of 10 to 100 mV on a voltage ramp, giving peak-shaped output sensitive to trace analytes.

Differential pulse-code modulation

Differential pulse-code modulation (DPCM) is a signal coding method that transmits the difference between each sample and a prediction from past samples instead of the sample itself.