Design methodology defined

Before proceeding to the designing methodology itself, it will be helpful to review and define some of the principles and concepts of partial control. We are concerned with the control of a system in which the number of process variables to be controlled is higher than the number of variables which are manipulated to realize this control. If all the process variables have to be controlled according to exact set points, the process has to abandoned or the design modified in order to provide the requisite number of manipulated variables. However, it is quite often the case that many of these variables need only be controlled within prescribed limits, hence the terminology of partial control. 

The SDS provides a detailed decomposition of the processes and functions defined in the FDS. The audit should establish that appropriate design methodologies have been applied leading to a structured modular and logical design. The SDS should provide sufficient detail to enable unambiguous implementation of the software. Table 31.10 provides the typical content of the SDS. 

In the previous section, we discussed the structure of a conceptual model that can be used to represent a design methodology. But the value of this model rests with the effectiveness of the representation schemes that one employs to describe the declarative and procedural components of the model in a way that the computer can understand. Thus, we are led to the need of defining a design-oriented language for the description of the computational process. 

In order to promote the generalisation of DWC in industrial application it is necessary to provide reliable design methodologies, but it is also very important to define strategies for a convenient startup of the column. The present paper proposes a new dynamic model for a DWC and applies it to formulate the startup control. 

We have said that the purpose of any experimental design is to provide the maximum amount of information at minimum cost from this it is evident that the design of experiments is a subject which involves not only statistical methodology but also economic considerations. If a most efficient design is defined as one which provides the greatest amount of information, every experiment should incorporate both efficiency and economy into the design failure to do so may mean a poor design, and this means wasted time, effort, or money, perhaps all three. 

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