The word validation has several uses:
In common usage, validation is the process of checking if something satisfies a certain criterion. Examples would include checking if a statement is true (validity), if an appliance works as intended, if a computer system is secure, or if computer data are compliant with an open standard. Validation implies one is able to document that a solution or process is correct or is suited for its intended use.
In engineering or as part of a quality management system, validation confirms that the needs of an external customer or user of a product, service, or system are met. Verification is usually an internal quality process of determining compliance with a regulation, standard, or specification. An easy way of recalling the difference between validation and verification is that validation is ensuring "you built the right product" and verification is ensuring "you built the product right." Validation is confirming that it satisfies stakeholder's or user's needs.
Validation can mean to declare or make legally valid or to prove valid or confirm the validity of data, information, or processes:
Validation of foreign studies and degrees.
In computer terminology, validation refers to the process of data validation, controlling that data inserted into an application satisfies pre determined formats or complies with stated length and character requirements and other defined input criteria.
In computer security, validation also refers to the process of assuring or authorizing that a user or computer program is allowed to do something.
In computer security, programs such as Validate (McAfee) are used to check program and data checksum values.
In the computer architecture and hardware world, validation refers to the process of verifying that the operations of the piece of hardware or architecture meets the specification. In some cases, validation not only refers to finding bugs in the hardware but also proving absence of certain critical bugs which may not have workarounds and may lead to project cancellation or product recall.
In psychology and human communication, validation is the reciprocated communication of respect which communicates that the other's opinions are acknowledged, respected, heard, and (regardless whether or not the listener actually agrees with the content), they are being treated with genuine respect as a legitimate expression of their feelings, rather than marginalized or dismissed.
In research psychology, validation is part of developing a test or questionnaire. A validated test has been shown to measure what it purports to measure, for example, showing that people with high scores on a questionnaire about risk-taking actually do take more risks than people with low scores. Compare to reliability, which means that the different items on a test all get at the same thing.
In the medical device, pharmaceutical and biotechnology manufacturing industries, validation refers to establishing documented evidence that a process or system, when operated within established parameters, can perform effectively and reproducibly to produce a medicinal product meeting its pre-determined specifications and quality attributes (from European Union Good Manufacturing Practices Guide, Annex 15). Regulatory bodies in the U.S., European Union, and Japan (amongst many others) require validation, causing it to become its own sub-industry supporting the pharmaceutical, biotechnology, and medical device industries.
in finance, validation is a process part of the "trade life-cycle."
Validation is important because it disallows data that can not possibly be either true or real to be entered into a database or computer system.
Validation against an incomplete or insufficient set of criteria can lead to a state of "validated" where "validated" does not confer the confidence that the term intends. Thus validation of the validation criteria is an important aspect that is often overlooked. Establishing such validation criteria can be a very difficult task when evaluating complex systems such as Air Traffic Management systems. Establishing "fitness for purpose" is often a more useful concept to support evaluation of complex systems in that the approach focuses on involving stakeholders in establishing and reviewing the purpose that the system must satisfy as the system emerges from early design. This allows flexibility in the evaluation process as ideas turn into detailed designs. Such flexibility is essential in the early development phases in order to avoid engineering white elephants. [The European Operational Concept Validation Methodology E-OCVM provides an approach to validating complex Air Traffic Management systems by establishing fitness for purpose in a world of shifting and incomplete validation criteria].
Varistor
A varistor is an electronic component with a significant non-ohmic current–voltage characteristic. The name is a portmanteau of variable resistor. Varistors are often used to protect circuits against excessive transient voltages by incorporating them into the circuit in such a way that, when triggered, they will shunt the current created by the high voltage away from the sensitive components. A varistor is also known as Voltage Dependent Resistor or VDR. A varistor’s function is to conduct significantly increased current when voltage is excessive.
*Note: only non-ohmic variable resistors are usually called varistors. Other, ohmic types of variable resistor include the potentiometer and the rheostat.
Euclidean vector
The magnitude of the vector is the length of the segment and the direction characterizes the displacement of B relative to A: how much one should move the point A to "carry" it to the point B. Many algebraic operations on real numbers such as addition, subtraction, multiplication, and negation have close analogues for vectors, operations which obey the familiar algebraic laws of commutativity, associativity, and distributivity. These operations and associated laws qualify Euclidean vectors as an example of the more generalized concept of a vector space.
Vectors play an important role in physics: velocity and acceleration of a moving object and forces acting on a body are all described by vectors. Many other physical quantities can be usefully thought of as vectors. The mathematical representation of a physical vector depends on the coordinate system used to describe it. Other vector-like objects that describe physical quantities and transform in a similar way under changes of the coordinate system include pseudovectors and tensors.
Vibration control
In earthquake engineering, vibration control is a set of technical means aimed to mitigate seismic impacts in building and non-building structures.
All seismic vibration control devices may be classified as passive, active or hybrid where:
Base isolator being tested at the UCSD Caltrans-SRMD facilitypassive control devices have no feedback capability between them, structural elements and the ground;
active control devices incorporate real-time recoding instrumentation on the ground integrated with earthquake input processing equipment and actuators within the structure;
hybrid control devices have combined features of active and passive control systems.
When ground seismic waves reach up and start to penetrate a base of a building, their energy flow density, due to reflections, reduces dramatically: usually, up to 90%. However, the remaining portions of the incident waves during a major earthquake still bear a huge devastating potential.
After the seismic waves enter a superstructure, there is a number of ways to control them in order to sooth their damaging effect and improve the building's seismic performance, for instance:
to dissipate the wave energy inside a superstructure with properly engineered dampers;
to disperse the wave energy between a wider range of frequencies;
to absorb the resonant portions of the whole wave frequencies band with the help of so called mass dampers
Volt
The volt (symbol: V) is the SI derived unit of electromotive force, commonly called "voltage (difference)". It is also the unit for the related but slightly different quantity electric potential difference (also called "electrostatic potential difference"). It is named in honor of the Lombard physicist Alessandro Volta (1745–1827), who invented the voltaic pile, possibly the first chemical battery (see Baghdad Battery).
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