I Design with Modeling Techniques

Chapter 17 - Vapor-liquid equilibrium (VLE) data are important for designing and modeling of process equipments. Since it is not always possible to carry out experiments at all possible temperatures and pressures, generally thermodynamic models based on equations on state are used for estimation of VLE. In this paper, an alternate tool, i.e. the artificial neural network technique has been applied for estimation of VLE for the binary systems viz. tert-butanol+2-ethyl-l-hexanol and n-butanol+2-ethyl-l-hexanol. The temperature range in which these models are valid is 353.2-458.2K at atmospheric pressure. The average absolute deviation for the temperature output was in range 2-3.3% and for the activity coefficient was less than 0.009%. The results were then compared with experimental data. 

A QA process model consists of elements representing software development staffs, software QA staffs, development activities, QA activities and documents generated. Our major concern, quality, is represented as defects density. Each element is represented as a node and is coimected based on its casual relation with other elements. Each node is further designated with 2 5 states representing its status, for example, the undesired event is represented as defect density at high status. In reality, the relation between QA process elements is not static and fixed, i.e., the influence of one node on the other node often exhibits probabilistic and interactive behavior. In order to represent the probabilistic behavior of QA process, we apply Bayesian Belief Network (BBN)(Jensen, 1996) technique. A typical QA process represented in BBN is shown in Fig 3. 

Instrumentation and Control (I C) systems are very often subject of probabilistic examination either within separate structural reliability analysis or Probabilistic Safety Assessment of a whole technological complex (e.g. Nuclear Power Plant). Use of programmable components in the design of these systems represents a challenge and utilizes the methods, which have been developed for components with a different behaviour. The typical method used for above mentioned examination is Fault Tree Analysis (FTA) (Vesely et al., 1981). The way of software faults modelling within Fault Trees vary a lot between particular models and there is no generally accepted modelling technique. 

FEIGL I d like to reply to Dr. Mirsky. As one of the few experimentalists in the room, I think it goes both ways. It s difficult for the experimentalist to keep up with the mathematics and the sophisticated techniques that you use. Your papers are hard for us to read so we don t design our experiments to answer exactly the questions that you would like answered. On the other hand, you often present us with models which don t relate to a whole generation s worth of experimental work that s been done in cardiac muscle mechanics. There is a lot of muscle mechanics that s been done and Dr. Mirsky s particularly aware of this. The potential beauty of the Haifa Model is that the linear papillary muscle type cardiac muscle mechanics may be incorporated into a global model. It can be tested at these two levels global perfomance and fiber cardiac mechanics. That gives us to two points to test and compare and that has a nice potential. It remains to be seen how much fruit it bears. 

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