Redundancy function

Very low-density lipoprotein receptor ( VLDLR) and APOE receptor-2 ( APOER2) are two gene family members with redundant functions. They are expressed in neurons of the developing brain and act as cell... 

Heber, S., Herms, J., Gajic, V. et al. Mice with combined gene knock-outs reveal essential and partially redundant functions of amyloid precursor protein family members. J Neurosci. 20 7951-7963,2000. 

Gutierrez-Ramos JC, Lloyd C, Kapsenberg ML, Gonzalo JA, Coyle AJ Non-redundant functional groups of chemokines operate in a coordinate manner during the inflammatory response in the lung. Immunol Rev 2000 177 31-42. 

Do, G.T., Pollet, B., Thevenin, ]., Sibout, R., Denoue, D., Barriere, Y., Lapierre, C. and Jouanin, L. (2007) Both caffeoyl coenzyme A 3-O-methyltransferase 1 and caffeic acid O-methyltransferase 1 are involved in redundant functions for lignin, flavonoids and sinapoyl malate biosynthesis in Arabidopsis. Planta, 226,1117-29. 

Rouzer, C.A., Mamett, L.J. 2007. Non-redundant functions of cyclooxygenase oxygenation of endo-cannabinoids. J. Biol. Chem. 282 in press. 

Yeast Su 2 is a heterocln oinatin component that silences transcription at silent mating loci, telomeres and the ribosomal DNA, and that also suppresses recombination in the iDNA and extends replicative life span. Mutational studies indicate that lysine 16 in the amino-terminal tail of histone H4 and lysines 9,14 and 18 in H3 are critically important in silencing, whereas lysines 5,8 and 12 of H4 have more redundant functions. Lysines 9 and... 

Ashcroft, G., Lei, K., and Jin, W. (2000) Secretory leukocyte protease inhibitor mediates non-redundant functions necessary for normal wound healing. Nature Medicine, 6, 1147-1153. 

Redundancy functions. A redundancy fimction is basically a checking function that builds double checks into a work process. Requiring countersignatures on a procedure is a simple form of redimdancy. 

To reduce the potential for common cause failures, diversity should be incorporated into the computer system architecture to the extent necessary to achieve the safety and reliability requirements for the overall computer system. Equipment diversity means that different types of equipment are used to perform redundant functions. Functional diversity means that different methods are used to cany out a particular function. 

Barth C, Jander G (2006) Arabidopsis myrosi-nases TGGl and TGG2 have redundant function in glucosinolate breakdown and insect defense. Plant J46 549-562. 

In some critical applications such as reconnaissance satellite or covert communication, satellite redundancy must be considered. This requires a system component, such as a battery charge controller, which is considered the smallest unit, to provide the redundant function necessary to achieve continuous operation aboard the satellite. 

Every function is described by one equation. In order to avoid redundancy, functional descriptions are only necessary at the lowest level where the function is worked out completely. If necessary, one could use a data dictionary, which shows all the variables and constants with a description, values and units, which is common for information systems. 

Main analysis for the architectural metrics is to make the safety relevant signal chains transparent and add adequate safety mechanism in case of weaknesses. Inspired by Robert Lusser, the signal chains are a chain of elements and the weakest parts should be enforced by means of safety mechanism. A typical safely mechanism consist of a part that can detect, malfunctions such as fault, errors or failure and a part that could control the malfunctions. It should be able to degrade the system to a safe state or switch to dissimilar redundant functions, which are identified as error free during runtime. Therefore, the entire signal chains and its elements (chain links) need to be identified. The quantification after Erich Pieruschka is primarily used to make the strengths of the chain links comparable. What is important The safety relevant function is first subject of the analysis. The correct functioning of the safety relevant function has to be assured. If this is provided by adequate measures such as implemented safety mechanism and control measures, this forms architecture to safety architecture. 

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