Performance-based logistics

In a V/f control generally, only the frequency is varied to obtain the required speed control. Based on this frequency, the switching logistics of the inverter control circuit control the inverter s output voltage using the PWM technique to maintain the same ratio of V/f. A W/control is, however, not suitable at lower speeds. Their application is limited to fan, pump and compressor-type loads only, where speed regulation need not be accurate, and their low-spccd performance or transient response is not critical and they are also not required to operate at very low speeds. They arc primarily used for soft starts and to conserve energy... 

Models of bioreactor performance usually only take into accoimt the intraparticle diffusion of nutrients if heterogeneity at the macroscale across the bioreactor can be ignored [89, 90]. For bioreactors in which there is heterogeneity at the macroscale, and even in some cases where there is no macroscale heterogeneity, to simplify the model it is common to use empirical equations that do not rely on nutrient or oxygen concentrations. These empirical approaches are conunonly based on the logistic equation, which reasonably describes the biomass profiles found in many SSF systems, with extended periods of acceleration and deceleration of growth ... 

Liquid propulsion is characterized by its high state of development, relatively complicated systems design, capability for repeated operation, long firing times, and of course the propellants employed. Their use has been based on a number of selection criteria, such as the operational mission, performance required, reliability, minimum weight, logistics, economics, availability, maintainability, mobility, and others. 

Availability, in general, is defined as the ability of the plant/equipment to perform its required function over a stated period of time. Maintainability is the probability that a failed item can be restored to operation effectiveness within a given period of time when repair action is performed as per the specified procedure (Smith, 2011). Software is available for performing RAM studies. For smaller projects, spreadsheets can be used. Reliability and process safety are interlinked, and so combined RAM and safety (RAMS) studies can be performed with the RAMS software (Sikos and Klemes, 2010). It considers many factors affecting the plant performance such as equipment performance, redundancy, demand requirements and logistics. RAM analysis is based on statistical failure data such as mean time between failures (MTBF), mean time to repair (MTTR), mean time to failure (MTTF) and mean down time (MDT). Wherever possible, failure data available within the company should be used for RAM/RAMS study. If not, typical failure data available in the literature/software can be used. 

These classification methods use different principles and rules for learning and prediction of class membership, but wiU usually produce a comparable result. Some comparisons of the methods have been given (i.e., Kotsiantis, 2007 Rani et al., 2006). Although the modem methods such as SVM have demonstrated very good performance, the drawback is that the model becomes an incomprehensible black-box that removes the explanatory information provided by, for example, a logistic regression model. However, classification performance usually outweighs the need for a comprehensible model. PCA has been used for classification based on bioimpedance measurements. Technically, PCA is not a method for classification but rather a method of data reduction, more suitable as a parameterization step before the classification analysis. 

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