Glossary of the key notions in Bionics and beyond

Equilibrium potential → The membrane potential at which the net (overall) current flow from one side of the membrane to the other is zero.

Equi-partition principle → By the equipartition principle the total energy is equally distributed among the degrees of freedom, if the gas that we have in a container is monoatomic (single atom) and therefore the atoms have no internal motions (rotation or vibration), the only motion that these molecules experience is translation. Each gas atom has three degrees of translational freedom, motion along the three direction of space. The average energy then per degree of freedom for the translating atomic gas is 1/2 kT per degree of freedom per gas atom.

Equivalent circuit → A theoretical electric circuit, which describes an I-V equation with an electrical circuit.

Ergodic process → A property of a random process. Broadly if the process has the same behavior averaged over time and over space (measured trials). Enables us to estimate statistical properties observing a stationer process for a time and averaging it over time.

Ergometer → ~ is a machine used for physical exercise. These range from simple spring-like devices to computerized electromechanical rides to recirculating-stream swimming pools.

Error backpropagation algorithm → A supervised learning method, which requires a teacher that knows (or can calculate) the desired output for any input in the training set. It is most useful for feed-forward networks (multilayer perceptrons).

Error correcting code → To disclose and eliminate the problems, we need to expand the code carrying the pure information with a bit or bits that increase the length of the code words so that with their help we can correct the code words, without changing their information content.

Error detecting code → To disclose and eliminate the problems, we need to expand the code carrying the pure information with a bit or bits that increase the length of the code words so that with their help we can control the code words, without changing their information content.

ESI (Electrospray ionization) → A technique for generating macromolecular ions for MS without degradation .

Essential and nonessential amino acids → Essential amino acids cannot be synthesized by human cells, they are taken up by protein digestion in the gastrointestinal tract

Essential tremor → ~ is a progressive movement disorder whose most characteristic feature is a rhythmic tremor of the arms, head and chin that is apparent during voluntary movements such as eating and writing.

EST (Expressed sequence tag) → A short sequence from a cDNA molecule that unambiguously identifies the corresponding gene.

Esters → ~ are chemical compounds derived by reacting an oxoacid (one containing an oxo group, X=O) with a hydroxyl compound such as an alcohol or phenol. ~are usually derived from an inorganic acid or organic acid in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group, and most commonly from carboxylic acids and alcohols.

Etalon → Permanent, authentic specimen.

Etching → ~ is the process of removing material from predefined areas of the surface of a wafer.

Ethers → Ether is a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R.[

Euler → Leonhard Euler (1707–1783) was a pioneering Swiss mathematician and physicist. He made important discoveries in fields as diverse as infinitesimal calculus and graph theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion of a mathematical function.

Euler equation → When the functional is a simple integral, Euler’s equation gives a powerful formula for quick calculation of the functional derivative.

Eulerian cycle → One that visits every edge in a graph exactly once.

Euler–Lagrange equations → The Euler–Lagrange equation is a differential equation whose solutions are the functions for which a given functional is stationary. Because a differentiable functional is stationary at its local maxima and minima, the Euler–Lagrange equation is useful for solving optimization problems in which, given some functional, one seeks the function minimizing (or maximizing) it.

Eutectic system → A mixture of chemical compounds with a given ratio that solidifies at a lower temperature than any other composition

Even parity code → The ~ (even parity) is the completed code where the number of 1s in the completed code word is even.

Event-related de/synchronization (ERD,ERS) → ERD is amplitude attenuation and ERS is amplitude enhancement of a certain EEG rhythm.occurring above the sensorimotor area of the neocortex. When people imagine moving, these brain rhythms first become weaker, then stronger. Imagined movements and thereby produced brain patterns are useful in a BCI.

Event-related fMRI design → In an event related design the course of the HDR following each stimulus presentation is estimated using the averaging of a single type of stimulus through repeated measures similar to event-related potental experiments.

Event-related Potential (ERP) → Any time locked potential change elicited by a sensory stimulus, or associated with execution of a motor, cognitive, or psychophysical task.

Evoked potential (EP) → Wave or complex elicited by and time-locked to a physiological or other stimulus, for instance an electrical stimulus, delivered to a sensory receptor or nerve, or applied directly to a discrete area of the brain.

Excitatory postsynaptic potential (EPSP) → The depolarization induced in the postsynaptic membrane that increases the likelihood of firing an action potential in the postsynaptic neuron.

Excited electron → Electron excitation is the movement of an electron to a higher energy state. This can either be done by photoexcitation (the original electron absorbs the photon and gains all the photon’s energy), or by electrical excitation (the original electron absorbs the energy of another, energetic electron), thermal excitation is a process where lattice vibrations provide enough energy to move electrons to a higher energy band.

Excited state → ~ is the state in which an atom or molecule picks up additional energy by heat or electricity, causing an electron to move into a higher-energy orbital.

Exo/Endo product → Exo and Endo are descriptors of the relative orientation of groups attached to non-bridgehead atoms in a bicycle alkane. If the group is orientated towards the highest numbered bridge it is given the description exo; if it is orientated away from the highest numbered bridge it is given the description endo.

Exogenous component → Short latency early EP component that are primarily determined by the physical parameters of the stimulus.

Exon → Sequence of a eukaryotic gene that appears in the mature mRNA after splicing.

Expectation value → In probability theory the expected value/expectation of a random variable is the weighted average of all possible values that this random variable can take on. The expected value, when it exists, is almost surely the limit of the sample mean as sample size grows to infinity.

Experimental frame → An ~ is a specification of the condition under which the system is observed or experimented with.

Expiratory Reserve Volume → After normal expiration, the further maximum expiration is approx. 1000 ml.

Exponential range → The part of the forward range, where the voltage-current function can be approximated exponentially.

Extension (Neuromorph Movement Control) → ~ is an unbending movement around a joint in a limb that increases the angle between the bones of the limb at the joint

Extensive properties → Their value is proportional to the amount of substance. They are additive.

Extensor muscle → The group of muscles that increase the angle between adjoining segments of a limb.

Extracellular space → The space located outside the cell membrane, which is occupied by fluid.

Extracellular unit activity → Action potentials of a given cell measured outside the cell.

Extratemporal → Outside of the temporal lobe.

Extremum → A maximum or a minimum of a mathematical function -called also extreme value (Latin extremus).

9. F

Fabless Design House → Design companies that design ICs, but manufacturing is done in dedicated factories.

Fading → It is a deviation of the attenuation over wireless channels. It is often modelled as a random process (Rayleigh fading, Rice fading, shadowing/lognormal fading)

Fading margin → System gain to accommodate expected fading, in order to ensure the required QoS (eg.: Bit-Error Rate) maintenance.

False positive → Rejecting the null hypothesis when it is in fact true. Also known as type I error.

Far field → In the field of electromagnetic radiation that emanates from an antenna the “far-field”, which extends from about two wavelengths distance from the antenna to infinity, is the region in which the field acts as “normal” electromagnetic radiation. The power of this radiation decreases as the square of distance from the antenna, and absorption of the radiation has no effect on the transmitter.

Faraday → Michael Faraday (1791–1867) was an English chemist and physicist (or natural philosopher, in the terminology of the time) who contributed to the fields of electromagnetism and electrochemistry.

Faraday’s law (of induction) → The law states that: The induced electromotive force (EMF) in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit. Alternatively: The EMF generated is proportional to the rate of change of the magnetic flux.

Fascicle → A muscle ~ is a bundle of skeletal muscle fibers surrounded by connective tissue.

Fast Fourier Transformation (FFT) → It is an algorithm to compute the DFT more quickly.

Fast-SPICE → SPICE simulators are capable to trade precision versus speed

Fatty acids → ~ are carboxylic acids with a long linear aliphatic chain.

Feed back dendritic inhibition → Regulation of the effectiveness of the pathway through interneurons innervated by the target (principal) cells of the pathway. The interneurons, in turn, inhibit the excitatory input of the principal neurons.

Feed forward dendritic inhibition → Regulation of the effectiveness of the pathway, which also provides afferents to interneurons inhibiting the target principal neurons of the pathway.

Feedback → ~ describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same event/phenomenon (or the continuation/development of the original phenomenon) in the present or future.

Feedback (neural networks) → Connection between two neurons, whereas the output is connected back into itself or to the local neurons

Feedback inhibition → In a feedback inhibitory circuit, increased firing of the excitatory cell elevates the inhibitory cell’s discharge frequency which, in turn, may decrease the excitatory cell’s output, providing a regulatory mechanism (negative feedback).

Feedforward (neural network) → A neural network type where only ~ type connections are allowed between the neurons.

Feed-forward inhibition → In a feed-forward inhibitory circuit, increased discharge of the inhibitory cell resulting from activation of afferent pathways, leads to the decreased activity of the targeted excitatory cell.

Feedforward neural network → A type of neural network where connections between the units do not form a directed cycle.

Fermi → Enrico Fermi (1901–1954) was an Italian-American physicist (Nobel Prize, 1938).

Fermi energy level of electron gas → Fermi level is the top of the collection of electron energy levels at absolute zero temperature. Electrons by the Pauli exclusion principle cannot exist in identical energy states, so at absolute zero they pack into the lowest available energy states and build up a “Fermi sea” of electron energy states. The Fermi level is the surface of that sea at absolute zero where no electrons will have enough energy to rise above the surface.

Fermi function → The ~ is a probability distribution function. It can only be used under equilibrium conditions. The conduction electron population for a metal is calculated by multiplying the density of conduction electron states and the ~. At higher temperature the transition between completely filled states and completely empty states is gradual rather than abrupt. The ~ is which describes this behavior.

Fermi´s golden rule → ~ is a way to calculate the transition rate (probability of transition per unit time) from one energy eigenstate of a quantum system into a continuum of energy eigenstates, due to a perturbation.

Fermi-Dirac statistics → ~ describes the energies of single particles in a system comprising many identical particles that obey the Pauli Exclusion Principle.

Fermion → A ~ (named after Enrico Fermi) is any particle which obeys the Fermi–Dirac statistics. A ~ can be an elementary particle (electron) or it can be a composite particle (proton). Particles with half-integer spin are fermions. Only one ~ can occupy a particular quantum micro state at any given time. If more than one ~ occupies the same physical space, at least one property of each ~, such as its quantum numbers or its spin, must be different.

FES (Functional electrical stimulation) → ~ is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis resulting from spinal cord injury (SCI), head injury, stroke and other neurological disorders. FES is primarily used to restore function in people with disabilities.

Feynman → Richard Phillips Feynman (1918–1988) was an American physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics (Nobel Prize, 1965) and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics.

Feynman‘s path integral → The path integral formulation of quantum mechanics is a description of quantum theory which generalizes the action principle of classical mechanics. It replaces the classical notion of a single, unique trajectory for a system with a sum, or functional integral, over an infinity of possible trajectories to compute a quantum amplitude. The complete method was developed in 1948 by Richard Feynman.

Fiber density → ~ means the number of muscle fibers or nerve fibers per unit of measurement.

FID (Free Induction Decay) → ~ a signal: If transverse magnetization of the spins is produced, e.g., by a 90° pulse, a transient MR signal will result that will decay toward zero with a characteristic time constant T2 (or T2*). This decaying signal is the ~. In practice, the first part of the ~ is not observable due to residual effects of the powerful exciting RF pulse on the electronics of the receiver, the receiver dead time.

Field effect → ~ is an experimentally observable effect of intramolecular coulombic interaction between the centre of interest and a remote unipole or dipole, by direct action through space rather than through bonds. The magnitude of the ~ (or ‘direct effect’) depends on the unipolar charge/dipole moment, orientation of dipole, shortest distance between the centre of interest and the remote unipole or dipole, and on the effective dielectric constant.

Field of view (FOV) in MRI → The rectangular region superimposed over the human body over which MRI data are acquired. Its dimensions are specified in length in each in-plane direction and are controlled by the application of frequency-encode and phase-encode gradients.

Fill factor → The photosensitive area divided by the pitch of the sensor array.

Filter → A ~ is a system which performs a filtering on it’s input. Every LTI system can be viewed as a filter. So in the field of DSP filters are equivalent with LTI systems

Filtration → 1 is the separation of a solid material from liquid.

Fingerprint region → The complex region of the infrared spectrum from 1500 to 400 1/cm.

Finite Impulse Response (FIR) model → A type of design matrix which assumes nothing about the shape of the haemodynamic response function. With a FIR model, you figure out how long a HRF you’d like to estimate - maybe 10 or 15 TRs following your stimulus and separately estimate beta weights for every time point; finally you line them up to form the timecourse of your HRF.

FIR – finite impulse response (filter) → A sytem (filter) which has a limited support impulse response.

First ionization energy → The energy required to remove (to infinity) one electron (the outermost) from the neutral atom, usually measured in eV (electronvolts) or kJ/mol

First law of Fick → A law for description of the process of diffusion. Formally J=4πr² D_AB d[B](r)/dr where J is the amount of substance crossing a spherical surface around a particle A in a time unit and D_AB=D_A+D_B is the relative diffusion coefficient of A and B.

First law of thermodynamics → dU=δq+δw, where dU is the differential of the internal energy, δq is the heat absorbed or emitted by the system and δw is the work performed by or on the system.

First order reaction → A reaction where the order with respect to the overall reaction is one. A reaction where the order is one for a reactant is a first order reaction with respect to that reactant.

Fixed boundary conditions → the value of the virtual cell is constant, fixed value

Fixed point → A stable point of the system dynamics where, under a constant input, the state of the system does not change.

Flame photometer → A photoelectric ~ is a device used in inorganic chemical analysis to determine the concentration of certain metal ions, among them sodium, potassium, lithium, and calcium.In principle, it is a controlled flame test with the intensity of the flame colour quantified by photoelectric circuitry. The sample is introduced to the flame at a constant rate. Filters select which colours the photometer detects and exclude the influence of other ions. Before use, the device requires calibration with a series of standard solutions of the ion to be tested.Flame photometry is crude but cheap compared to flame emission spectroscopy, where the emitted light is analysed with a monochromator. Its status is similar to that of the colorimeter (which uses filters) compared to the spectrophotometer (which uses a monochromator). it also has the range of metals that could be analysed and the limit of detection are also considered

Flash photolysis → A method for measurement of reaction rate where the reaction is started by a flash light. Very fast reactions can be investigated by this method.

Flexion → A bending movement around a joint in a limb that decreases the angle between the bones of the limb at the joint

Flexor muscle → The group of muscles that decrease the angle between bones on two sides of a joint.

Flip angle → Amount of rotation of the macroscopic magnetization vector produced by an RF pulse, with respect to the direction of the static magnetic field.

Floating-point number representation → Basic idea: A = M x 10^k, where M is the coefficient and K is the exponent or characteristic

Flow graph → A graphical representation of a system wireing together the basic operations and telling the directions of the signal flows.

Fluorescence microscope → A ~ is an optical microscope used to study properties of organic or inorganic substances using the phenomena of fluorescence and phosphorescence instead of, or in addition to, reflection and absorption.

Fluorescent → Material e mission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength (in our case: x-ray radiation).

Fluoroscopy → Continuous series of images using x-ray radiation.

FMO (Fragment molecular orbital method) → ~ is a computational method that can compute very large molecular systems with thousands of atoms using ab initio quantum-chemical wave functions.

Foam cell → A macrophage in the arterial wall which has been overloaded with cholesterol

Focus → A (stable or unstable) fixed point where the nearby trajectories form a spiral shape.

Folding funnel → The free energy surface of a protein chain is assumed to have a funnel shape. It explains that the folding can occur on multiple pathways and relatively fast.

Forbidden band → A range of unallowed energy levels for an electron in a solid. A forbidden band gap is between the valence band and conduction band.

Force carriers → All interactions which affect matter particles are due to an exchange of force carrier particles, a different type of particle altogether. These particles are tossed between matter particles. What we normally think of as “forces” are actually the effects of force carrier particles on matter particles.

Formal equivalence checking → Formal comparison of the final logic functionality with the original RTL code

Formation of deoxythymidylate → Deoxythymidylate is formed from dUMP by the action of thymidylate synthase. A methyl group is supplied by methylene-tetrahydrofolate. The inhibition of this reaction is used for treatment of cancer patients.

Forward range → The voltage range where there is current in the semiconductor.

Four fundamental interactions → Fundamental interactions (sometimes called interactive forces) are the ways that the simplest particles in the universe interact with one another. An interaction is fundamental when it cannot be described in terms of other interactions. The four known fundamental interactions, all of which are non-contact forces, are electromagnetism, strong interaction, weak interaction and gravitation.

Four fundamental notions: space-time-body-force → Mechanics, which has hitherto been based on the Newtonian laws of motion, is profoundly affected by the measurements of space, time, and force. This laws may be expressed analytically in terms of the ordinary coordinates of the particle (bodies) the force acting on it, in the ordinary sense of the term.

Fourier series → It is a specific type of infinite mathematical series involving only trigonometric - sine and cosine - functions, and a constant. 

Fourier transform → The Fourier transform ‘transforms’ one complex-valued function of a real variable into another. In effect, the Fourier transform decomposes a function into oscillatory functions.