Information about Redundancy (engineering)
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Redundant power supply
Redundancy in engineering is the duplication of critical s of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe.
In many safety-critical systems, such as fly-by-wire aircraft, some parts of the control system may be triplicated.[1] An error in one component may then be out-voted by the other two. In a triply redundant system, the system has three sub components, all three of which must fail before the system fails. Since each one rarely fails, and the sub components are expected to fail independently, the probability of all three failing is calculated to be extremely small. Redundancy may also be known by the terms "Majority voting systems"[2] or "voting logic".[3]
Forms of Redundancy
There are four major forms of redundancy, these are:- Hardware redundancy, such as TMR
- Information redundancy, such as Error detection and correction methods
- Time redundancy, including transient fault detection methods such as Alternate Logic
- Software redundancy such as N-version programming
See also
References
- ^ Redundancy Management Technique for Space Shuttle Computers (PDF), IBM Research
- ^ Majority voting systems
- ^ Designing Integrated Circuits to Withstand Space Radiation
- ^ Using powerline as a redundant communication channel
External links
Redundancy, in general terms, refers to the quality or state of being redundant, that is: exceeding what is necessary or normal; or duplication. This can have a negative connotation, especially in rhetoric: superfluous or repetitive; or a positive implication, especially
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Engineering is the applied science of acquiring and applying knowledge to design, analysis, and/or construction of works for practical purposes. The American Engineers' Council for Professional Development, also known as ECPD,[1] (later ABET [2]
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System (from Latin systēma, in turn from Greek σύστημα systēma) is a set of entities, real or abstract, where each entity interacts with, or is related to, at least one other
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A fail-safe or fail-secure describes a device which, if (or when) it fails, fails in a way that will cause no harm or at least a minimum of harm to other devices or danger to personnel.
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A life-critical system or safety-critical system is a system whose failure or malfunction may result in:
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- death or serious injury to people, or
- loss or severe damage to equipment or
- environmental harm.
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aircraft is a vehicle which is able to fly through the air (or through any other atmosphere). All the human activity which surrounds aircraft is called aviation. (Most rocket vehicles are not aircraft because they are not supported by the surrounding air).
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In computing, triple modular redundancy (TMR) is a fault tolerant form of N-modular redundancy, in which three systems perform a process and that result is processed by a voting system to produce a single output.
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In mathematics, computer science, telecommunication, and information theory, error detection and correction has great practical importance in maintaining data (information) integrity across noisy channels and less-than-reliable storage media.
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N-version programming (NVP), also known as multiversion programming, is a method or process in software engineering where multiple functionally equivalent programs are independently generated from the same initial specifications [1].
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A common mode failure occurs when events are not statistically independent. That is, one event causes multiple systems to fail.
An example is when all of the pumps for a fire sprinkler system are located in one room.
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An example is when all of the pumps for a fire sprinkler system are located in one room.
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In computer storage, data redundancy (sometimes incorrectly referred to as data reliability) is a property of some disk arrays (most commonly in RAID arrays) which provides fault tolerance such that if some disks fail, all or part of the data stored on the array can
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Double switching is the practice in railway signalling in particular of cutting the power to a relay in both the positive and negative sides, so that a single false feed of current to that relay is unlikely to cause a wrong side failure. It is analogous to double insulation.
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Fault-tolerant design refers to a method for designing a system so it will continue to operate, possibly at a reduced level (also known as graceful degradation), rather than failing completely, when some part of the system fails.
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Radiation hardening is a method of designing and testing electronic components and systems to make them resistant to damage or malfunctions caused by high-energy subatomic particles and electromagnetic radiation, such as would be encountered in outer space, high-altitude flight and
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Reliability engineering is an engineering field, that deals with the study reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time.[1] It is often reported in terms of a probability.
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Reliability theory of aging and longevity is a scientific approach aimed to gain theoretical insights into mechanisms of biological aging and species survival patterns by applying a general theory of systems failure, known as reliability theory.
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Safety engineering is an applied science strongly related to systems engineering and the subset System Safety Engineering. Safety engineering assures that a life-critical system behaves as needed even when pieces fail.
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self-healing ring, or SHR, is a common configuration in telecommunications transmission systems. SDH, SONET and WDM systems are often configured in self-healing rings.
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Description
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