Concept Of Redundancy Research Articles

Limit Checking Using the Algorithmic Redundancy Approach

A new type of redundancy to be used by fault diagnostic methods is defined in this paper. The algorthmic redundancy concept is presented in the context offered by the temporal, material, and analytical redundancies. An original solution in the field of diagnostic assistant systems is brought today by the DIALOGS software, the result of more than three years of collaboration between five industrial and three academic European partners. The main concepts of the DIALOGS project are briefly presented. and a statistical limit checking method is used to illustrate the implementation of the algorithmic redundancy approach.

Species Redundancy and Ecosystem Reliability

The concept of species redundancy in ecosystem processes is troublesome because it appears to contradict the traditional emphasis in ecology on species singularity. When species richness is high, however, ecosystem processes seem clearly insensitive to considerable variation in biodiversity. Some elementary principles from reliability engineering, where engineered redundancy is a valued part of systems design, suggest that we should rethink our stance on species redundancy. For example, a central tenet of reliability engineering is that reliability always increases as redundant components are added to a system, a principle that directly supports redundant species as guarantors of reliable ecosystem functioning. I argue that we should embrace species redundancy and perceive redundancy as a critical feature of ecosystems which must be preserved if ecosystems are to function reliably and provide us with goods and services. My argument is derived from basic principles of reliability engineering which demonstrate that the probability of reliable system performance is closely tied to the level of engineered redundancy in its design. Empirical demonstrations of the value of species redundancy in ecosystem reliability would provide new insights into the ecology of communities and the value of species conservation.Redundancia de Especies y Confiabilidad del EcosistemaEl concepto de redundancia de especies en procesos ecológicos es problemático puesto que aparentemente contradice el énfasis tradicional en ecologia sobre la singularidad de las especies. Sin embargo, cuando la riqueza de especies es alta, los procesos del ecosistema parecen claramente insensibles a variaciones considerables de la biodiversidad. Principios elementales de confiabilidad en ingenieria, donde la redundancia es evaluada como parte del diseño de sistemas, sugiere que deberíamos repensar nuestra postura sobre la redundancia de especies. Por ejemplo, un principio central de confiabilidad ingenieril es que la confiabilidad siempre incrementa cuando componentes redundantes son agregados al sistema, un sistema que directamente soporta especies redundantes como garante del funcionamiento del ecosistema. Yo argumento que deberíamos abarcar la redundancia de especies y percibir redundancia como una característica crítica del ecosistema que debe ser conservada si los ecosistemas funcionaran confiablemente y nos provean de bienes y servicios. Demostraciones empíricas de el valor de la redundancia de especies en confiabilidad de ecosistemas provee nuevas intuiciones dentro de la ecología de comunidades y el valor de la conservación de las especies.

Multi-joint coordination strategies for straightening up movement in humans

Complex movement execution theoretically involves numerous biomechanical degrees of freedom, leading to the concept of redundancy. The kinematics and kinetics of rapid straightening up movement from the squatting position were analysed with the optoelectronic ELITE system in 14 subjects. We found multiple acceleration and deceleration peaks for the hip, knee and ankle joints during the early extension phase of the movement. In order to test the temporal coordination between the angular acceleration of these joints, conjugate crosscorrelation functions (CCF) between each set of two variables were calculated. We found a bimodal distribution of the maximum CCF in positive and negative values suggesting the existence of two distinct strategies, the in-phase and the out-of-phase strategy for each pair of joints. The hip and knee coordination strategies (in- or out-of-phase) were well conserved in each subject for repetitive movements. Combination of joint pair strategies was more reproducible for the hip-knee/knee-ankle pair than for the other combinations, suggesting that the straightening up strategies are organised around the knee. We conclude that mastering of the redundancy problem can be realised by using coordination strategies characterised by opposed joint acceleration patterns.

Quantifying structural redundancy in ecological communities.

In multivariate analyses of the effects of both natural and anthropogenic environmental variability on community composition, many species are interchangeable in the way that they characterise the samples, giving rise to the concept of structural redundancy in community composition. Here, we develop a method of quantifying the extent of this redundancy by extracting a series of subsets of species, the multivariate response pattern of each of which closely matches that for the whole community. Structural redundancy is then reflected in the number of such subsets, which we term "response units", that can be extracted without replacement. We have applied this technique to the effects of the Amoco-Cadiz oil-spill on marine macrobenthos in the Bay of Morlaix, France, and to the natural interannual variability of macrobenthos at two stations off the coast of Northumberland, England. Structural redundancy is shown to be remarkably high, with the number and sizes of subsets being comparable in all three examples. Taxonomic/functional groupings of species within the differing response units change in abundance in the same way over time. The response units are shown to possess a wide taxonomic spread and, using two different types of randomisation test, demonstrated to have a taxonomically and functionally coherent structure. The level of structural redundancy may therefore be an indirect measure of the resilience or compensation potential within an assemblage.

The Sociological Implications of Voluntary Redundancy: The South Australian Experience

The experience of voluntary redundancy on the current scale is fairly new in Australia and its impact on workers and society is only just beginning to be observed and interpreted. Under the economic rationalist policies of successive federal governments which promoted a free market economy driven by privatisation, deregulation and de-institutionalisation, Australia has undergone considerable structural change in the 1990s. This change has been marked by government-supported labour restructuring, within both the private and public sectors of industry. The purpose of the study was to explore the concept of voluntary redundancy, whether mature-aged workers were being targeted, and the sociological implications of voluntary redundancy for workers in South Australia.

An evaluation of what the mouse knockout experiments are telling us about mammalian behaviour

The early gene knockout studies with a neurobiological focus were directed at fairly obvious target genes and added very little to our knowledge of behavioural neuroscience. On the contrary, since the behavioural consequences were often predictable, this helped confirm that the technology was working. However, a substantial number of knockouts of genes expressed in the brain have been without obvious behavioural consequences, supporting the concept of genetic canalisation and redundancy. Others have produced a behavioural deficit for which there is no obvious explanation. Many cells of different tissue types have a capacity for memory, and in the brain, cells of the hippocampus are important for spatial learning and memory. Deleting genes that are expressed in the hippocampus has received considerable attention in this behavioural context. Although the initial studies experienced problems of interpretation, considerable advances have since been made. Knockout mice are now subject to tests of different forms of learning, multicellular hippocampal recordings, and restricted gene deletion specific to cells of component regions. This multi-level approach is proving more informative. Nevertheless, there is still a need to recognise that behavioural expression is several steps removed from gene expression, and that the relationship between genes and behaviour can be reciprocal.

On redundancy in multi criteria decision making

The concept of redundancy is accepted in Operations Research and Information Theory. In Linear Programming, a constraint is said to be redundant if the feasible decision space is identical with or without the constraint. In Information Theory, redundancy is used as a measure of the stability against noise in transmission. Analogies with Multi Criteria Decision Making (MCDM) are indicated and it is argued that the redundancy concept should be used as a regular feature in conditioning and analysis of Multi Criteria Programs. Properties of a proposed conflict-based characterisation are stated and some existence results are derived. Redundancy is here intended for interactive methods, when the efficient set is progressively explored. A new redundancy test for the linear case is formulated from the framework. A probabilistic method based on correlation is proposed and tested for the non-linear case. Finally, some general guidelines are given concerning the redundancy problem.

Structural Sensitivity as a Measure of Redundancy

The conventional definition of redundancy is applicable to skeletal structural systems only, whereas the concept of redundancy has never been discussed in the context of a continuum. Generally, structures in civil engineering constitute a combination of both skeletal and continuum segments. Hence, this paper presents a generalized definition of redundancy that has been defined in terms of structural response sensitivity, which is applicable to both continuum and discrete structures. In contrast to the conventional definition of redundancy, which is assumed to be fixed for a given structure and is believed to be independent of loading and material properties, the new definition would depend on strength and response of the structure at a given stage of its service life. The redundancy measure proposed in this paper is linked to the structural response sensitivities. Thus, the structure can have different degrees of redundancy during its lifetime, depending on the response sensitivity under consideration. It is believed that this new redundancy measure would be more relevant in structural evaluation, damage assessment, and reliability analysis of structures at large.

On the redundancy of fuzzy partitions

We introduce a concept of redundancy for families of fuzzy subsets, based on a left continuous t-norm and its corresponding Φ-operator, and study its basic properties, including a characterization of families with redundancy zero in some important special cases. Examples illustrate that, in the case of t-norms with zero divisors, several definitions for fuzzy partitions from the literature are insensitive to the phenomenon of redundancy. Finally, a geometric interpretation of the redundancy based on the Łukasiewicz t-norm and an upper bound for its value are given.

Array redundancy for active line arrays

Active imaging arrays are used to image scenes composed of reflectors of transmitted radiation, and in many such applications, line arrays are employed. In this paper, we discuss scanned active line arrays for imaging based on image synthesis. We define the novel concept of array redundancy for active arrays, analogous to the well-known concept of redundancy applied to passive arrays, and we define and give examples of minimum redundancy and reduced redundancy line arrays composed of transmit/receive elements. Such arrays differ from their passive imaging counterparts both in geometry and in element count.

FAULT DETECTION AND DIAGNOSIS IN BATCH AND SEMI-BATCH PROCESSES USING ARTIFICIAL NEURAL NETWORKS

Abstract The objective of this work is to assess the feasibility of adopting artificial neural networks (ANNs) in fault detection and diagnosis for batch and semi-batch processes. Although there is a large volume of related publications available, most of them used steady-state data to train ANNs and, as such, the task of fault diagnosis can only be implemented in continuous operations. Based upon the concept of analytical redundancy, the framework of a two-stage fault monitoring system is proposed in this paper. In the first stage, a hybrid ANN is adopted to predict the long-term dynamic behaviors of the output variables under normal condition. The occurrence of fault(s) can be detected by inspecting the residuals, i.e. the differences between the measured and the predicted values of outputs. A second feedforward neural network is then used for the purpose of differentiating the residual patterns caused by various faults. In addition to the fact the results of pilot tests are quite satisfactory, it is al...

Optical isomers of 3,13-dimethylheptadecane: Sex pheromone components of the western false hemlock looper,Nepytia freemani (Lepidoptera: Geometridae)

(3S, 13R)-3, 13-Dimethylheptadecane [(3S, 13R)-3, 13-dime-17Hy] is the major pheromone component of the western false hemlock looper (WFHL),Nepytia freemani. In comparative gas chromotographic-electroantennographic detection (GC-EAD) analyses of stereoselectively synthesized isomers, 1 pg of (3S, 13R)-dime-17Hy elicited significantly stronger electrophysiological responses by male WFHL antennae than did 1 pg of separately injected (3R, 13R)-, (3R, 13S)- or (3S, 13S)-3, 13-dime-17Hy. In field experiments with individually tested stereoisomers. (3S, 13R)-3, 13-dime-17Hy was the only stereoisomer to attract males, but the four-stereoisomer blend was 3.6 times more attractive. Quaternary and all binary combinations of (3S, 13R)-3, 13-dime-17Hy with the other stereoisomers were equally attractive, suggesting that synergisytic behavioral activity in WFHL resided with either one of (3R, 13R)-, (3R, 13S)-, or (3S, 13S)-3, 13-dime-17Hy. Because optical isomers of (di)methylhydrocarbons do not separate on currently available columns, it remains unknown whether female WFHL also produce a four-stereoisomer pheromone blend. Substitutionality of pheromone stereoisomers without loss of behavioural activity has not previously been reported, but favorably compares with the concept of pheromone redundancy that was first suggested for the multiple pheromone component blend of the cabbage looper moth,Trichoplusia ni.

Mice lacking all isoforms of retinoic acid receptor β develop normally and are susceptible to the teratogenic effects of retinoic acid

Retinoic acids (RA) are vitamin A derivatives essential for normal embryonic development and viability of vertebrates. The RA signal is mediated by two distinct classes of receptors, RA receptors (RARs) and retinoid X receptors (RXRs). The RAR family is composed of three genes: RARα, β, and γ. The expression of RARβ gene is spatially and temporally restricted in certain structures in the developing embryo, suggesting that RARβ could play specific roles during morphogenesis. Four isoforms of the RARβ gene (β1–β4) are generated by differential usage of promoters and alternative splicing. It has recently been demonstrated that the RARβ2 isoform is dispensable for normal development. To ascertain the function of all RARβ isoforms in vivo, we have generated a mutation that disrupts all isoforms of the RARβ gene in the mouse by gene targeting in embryonic stem cells. Mice homozygous for the mutation are viable and fertile with no externally apparent abnormalities. During development, 1 11 RARβ mutant embryos showed fusion of the ninth and tenth cranial ganglia on both sides of the hindbrain. However, no obvious alterations in the spatial pattern of expression of Hoxb-1, Hoxb-4 and Hoxb-5 were observed in day 9.5 p.c. embryos. The RARβ null mutation did not alter the pattern or extent of the limb and craniofacial malformations induced by RA excess, suggesting that RARβ may not be mandatory to mediate the observed teratological effects of RA in these structures. These experiments demonstrate that RARβ isoforms are not absolutely required for embryonic development and provide additional support to the concept of functional redundancy among members of the RAR family.

Model based diagnosis for automotive engines-algorithm development and testing on a production vehicle

A complete diagnostic algorithm is presented for detecting and isolating faults of actuators and sensors of an automotive engine. The algorithm is built around the concept of analytical redundancy and utilizes structured parity equations. The parity equations rely on a nonlinear and dynamic model, obtained by identification using data from a single production vehicle with a 3.1 l V-6 engine. Tests performed with the diagnostic algorithm on the same vehicle show excellent performance under different fault conditions. Several important issues require further investigation, including long-term climatic effects, vehicle aging, car-to-car variations, the automation of the calibration procedure and implementation in the face of processor limitations. >

The timelessness of quantum gravity: I. The evidence from the classical theory

The issue of time is addressed. It is argued that time as such does not exist but that instants, defined as complete relative configurations of the universe, do. It is shown how the classical mechanics (both non-relativistic and generally relativistic) of a complete universe can be expressed solely in terms of such relative configurations. Time is therefore a redundant concept, as are external inertial frames of reference (so that Machian ideas about the relativity of motion are fully implemented). Although time plays no role in kinematics, it can be recovered as an effective concept associated with any classical history of the universe. In the case of classical mechanics, this operationally defined time is identical to the astronomers' ephemeris time. In the case of general relativity it is shown how local proper time is a kind of local ephemeris time. It is argued that because general relativity is timeless in a deep and precise sense, the standard representation of the theory as a theory of curved spacetime disguises important aspects of its structure and that just these aspects may be the most important for the quantum form of the theory. This issue and the effective recovery of time from a genuinely timeless quantum theory are addressed in a following companion paper.

Heat shock-induced cell death in murine microvascular endothelial cells depends on priming with tumor necrosis factor-alpha or interferon-gamma.

We previously reported that sequential exposure of cultured porcine aortic endothelial cells to lipopolysaccharide (LPS) and then to inducers of the heat shock response resulted in lethal injury by programmed cell death. In these present experiments, we evaluated the ability of other mediators of sepsis to prime endothelial cells for subsequent injury upon heat shock induction. We used SVEC4-10 microvascular endothelial cells, a cloned SV40-transformed cell line derived from LPS-resistant C3H/HeJ mice. When these endothelial cells were treated first with tumor necrosis factor-alpha followed by induction of the heat shock response with either heat or sodium arsenite (As), a standard chemical inducer of the heat shock response in vitro, a tumor necrosis factor dose-dependent cytotoxicity was observed, similar to that which we had seen previously in porcine endothelial cells primed with LPS. Subsequent experiments found that priming with interferon-gamma produced a similar dose-dependent toxicity upon heat shock with either heat or As. The reducing agents dithiothreitol and n-acetylcysteine, which we have previously shown to inhibit heat shock-induced programmed cell death in LPS-primed porcine endothelial cells, were also effective in protecting against heat shock-induced death following cytokine-priming in this microvascular cell line, suggesting that the intracellular signaling pathways of these priming agents are somewhere convergent. These data suggest that both exogenous and endogenous mediators of inflammation can prime endothelial cells for subsequent injury upon induction of the heat shock response, and are consistent with the emerging concept of redundancy in inflammatory signaling.

Occurrence of common mode failure

Abstract In technical facilities, for example in nuclear power plants, redundant systems are used to prevent random failures from deleting the complete system function. However, although this redundancy concept is adequate to cope with random failures in single redundancies, its applicability is limited in case of multiple failures due to a systematic failure cause to which all redundancies are submitted due to their identical features. Some general considerations have been formulated to rule out the occurrence of such common mode failure (CMF) in redundant systems under certain circumstances. CMF means that in more than one redundancy the systematic failure cause is activated at the same time, or within the same frame of time (e.g. during the mission time for an accident). It therefore has to be distinguished between the systematic cause and the actual occurrence of CMF: a latently existing systematic cause does not necessarily lead to simultaneous failure; it must be activated and therefore is only the prerequisite for CMF. A systematic cause results in simultaneous failure if • —the systematic cause is activated by specific circumstances associated with the accident: a triggering effect to which the redundancies are subjected due to their identical features. • —previous failures have accumulated undetectedly before the accident. They now appear on demand due to the accident. For exclusion of CMF, both exclusion of a triggering effect and of accumulation is necessary. A trigger can be excluded, if the components are not affected by the accident at all, or are not submitted to any ‘abnormal’ operation. Accumulation can be ruled out by self annuciation. From this a matrix for excluding CMF-susceptibility has been derived.

Image Encoding, Labeling, and Reconstruction from Differential Geometry

In this paper we consider how the representation of images as surfaces, and their characterizations via surface differential forms, can be related to the concept of redundancy in the intensity signal. In contrast to common approaches, the basic surface types (planar, parabolic, elliptic/hyperbolic) are not seen as equal-priority classes, but as corresponding to different degrees of redundancy. This leads to a new approach to image representation and region labeling based upon generalized curvature measures. Furthermore, we employ different reconstruction algorithms to show that elliptic surface patches carry the significant information in natural images. Based upon deterministic and stochastic relaxation techniques, these algorithms allow one to reconstruct the original image from (i) "elliptic intensities" only and (ii) curvature measures which are zero for nonelliptic regions.

Image Encoding, Labeling, and Reconstruction from Differential Geometry

In this paper we consider how the representation of images as surfaces, and their characterizations via surface differential forms, can be related to the concept of redundancy in the intensity signal. In contrast to common approaches, the basic surface types (planar, parabolic, elliptic/hyperbolic) are not seen as equal-priority classes, but as corresponding to different degrees of redundancy. This leads to a new approach to image representation and region labeling based upon generalized curvature measures. Furthermore, we employ different reconstruction algorithms to show that elliptic surface patches carry the significant information in natural images. Based upon deterministic and stochastic relaxation techniques, these algorithms allow one to reconstruct the original image from (i) "elliptic intensities" only and (ii) curvature measures which are zero for nonelliptic regions.

The Coded Microprocessor Certification

In France, the coded microprocessor is certified as a fail-safe component. It is increasingly used in Automatic Train Protection in the guided transport systems. The safety operation of coded microprocessor is based on the information redundancy concept using an error-detecting codes. This redundancy allows a high level of protection against all types of microprocessor failures, as well as against compiler errors. Two coded microprocessor types have been certified by French Duly Authorised Body : -the first one uses a separable code with two fields : 32 bits of data information and 48 bits of check word. It was certified in 1989 and used in the protection of ligne A of the Paris RER express metro and of the POMA system in Laon. -the second one differs from the first by the check word length which is 31 bits. A new certification has been necessary for this second type which will be used in the MAGGAJLY (Metro Automatique & Grand Gabarit de Lyon) system in the line D. Other applications will be put into service shortly in the track-side equipment of the VAL (Vehicule Automatic Leger) in Chicago (fullfilling many operational features: two-way operation, shuttle and run around) and also in the Channel Fixed Link signaling system. In this paper we present a brief introduction to the coded microprocessor principles and explain the main steps of safety proof which have been necessary to certify this component according a safety objective). The error detection capabilities using an arithmetic code and signature technique as well as the assessment of the probability of an undetected error will be presented. We also describe the certification process and organization.