Degree of redundancy

Also, for this option, several levels can be observed concerning the integration of the airflow model. The lowest level of integration still requires separate input for the thermal and the airflow model respectively with a high degree of redundancy in the input parameters (e.g., zones must be input for both models), and the connectivity of the airflows and the zones in the thermal model must be established manually by the user. More sophisticated levels have reduced redundancy and automatic establishment of the link connectivity. 

The bulk system has long been seen as a vital element in the maintenance of an economic and reliable supply of electrical energy in North America, and a high degree of redundancy has been incorporated to achieve this objective. The North American Electric Reliability Council (NERC) was formed in 1968, following the November 9-10, 1965, blackout that affected the northeastern United States and Ontario,... 

Systems are designed to function normally even when a single instrument or control function fails. This is achieved with redundant controls, including two or more measurements, processing paths, and actuators that ensure that the system operates safely and reliably. The degree of redundancy depends on the hazards of the process and on the potential for economic losses. An example of a redundant temperature measurement is an additional temperature probe. An example of a redundant temperature control loop is an additional temperature probe, controller, and actuator (for example, cooling water control valve). 

Safety Integrity Level (SIL) - The degree of redundancy and independence from the effects of inherent and operational failures and external conditions that may affect system performance. 

Redundant piping system. Redundant piping systems can be installed, especially in conjunction with dual daytanks, to enable a complete cleanout of the delivery system between slurry batches. When this degree of redundancy is chosen, a totally separate slurry dispense machine is included to permit a backup for all major components. 

Studies with knockout mutant mice lacking one or another of the retinoid receptors suggest that there is some degree of redundancy or overlap between the receptor subtypes, and that RARy is especiallyimportant in the teratogenic actions of retinoids (Section 2.5.1.1 Mark et al., 1999 Maden, 2000) ... 

Some of the steps in the validation fife cycle will not be needed in some validation projects. For instance, the use of preferred suppliers for software and hardware products or services removes the need for repeated supplier appraisal and selection. Life-cycle steps, however, cannot be eliminated for packaged systems with embedded computer system systems purchased from, or subcontracted to, a vendor. The degree of redundancy in the life-cycle model used for validating existing computer system systems will be specified in the Validation Master Plan. 

We would stress the fact that a key for a safe and reliable operation of SCF equipment consists of very cautious training of the operators. Moreover, automation is required with a high degree of redundancy taking into account all potential issues (fire, electrical power or intrument air failure, computer or intrument problems, etc.). 

Chemokines constitute a large family of about 50 proteins that interact with about 20 different receptors. Cbemokines play a crucial biological role in inflammation, immunity and viral infection. In spite of certain degree of redundancy, the chemokine system presents several levels of specificity in terms of receptor interaction, target cells and biological functions. The relevance of certain chemokines in specific immune responses is also suggested by the expression of selected chemokine-like proteins or chemokine-receptors by viruses as way to escape host response. 

As explained, the Pinch Design method generates a network with a certain degree of redundancy. The reduction of units can contribute to major saving in capital costs. However, more energy is necessary to inject into the network to restore infeasible driving forces. This task can be treated elegantly by optimisation. 

Unlike representation of functions using wavelet basis functions, there are many different combinations of wavelet packet basis functions that can be used in signal representation. Hence there is some degree of redundancy. With redundancy comes choice, and Section 3 discusses one approach for selecting a set of basis functions. 

The safety design of a plant results from extensive analyses (cf. [2]) to be discussed later. The dimensioning of safety systems is also carried out deterministically. It is based on the concept of disturbances which have to be avoided, for example a cooling failure in a reactor for an exothermal reaction. This is the basis for determining the type and capacity of the safety system coping with it. Its quality and degree of redundancy may then be determined... 

If there are several such combinations these are input into an OR -gate just as the contributions of several initiating events to the undesired event. The components which hgure together with the initiating event are called redundant. Their number indicates the degree of redundancy. Fault trees are elaborated according to... 

In addition, the probability of individual events depends on the degree of redundancy of the observed system. For example, the probability of a common cause failure of two components in a system with two redundant components is not the same as that in a system with four redundant components, even if all parameters with relevance for the failure behaviour are identical. This is because one generally believes that CCFs are caused by hidden component flaws or hidden environmental influences and the number of components affected depends on the number of redundant component present (e.g. the same cause affecting two components in a twofold redundant system could only affect one in a non-redundant system and three in a threefold redundant system). Thus, conversions and adaptations are necessary, as described in detail in [48]. 

However, the application of the model to systems with higher degrees of redundancy is problematic. This was reason for extending the Beta Factor Model to the Multiple Greek Letter (MGL) Model [48]. 

The degree of redundancy becomes higher compared to a 2 x 100% or N+1 concept. Therefore the allocation of time to repair in case of unplanned unavailability of an equipment becomes higher too. The repair can therefore be performed with a better preparation and without excessive pressure put on the working staff. Considering human factor issues there is an evident gain in safety linked to maintenance costs reduction. 

---