Optimization-based strategies

Detailed analysis of these strategies would go far beyond the mandate of this book. Hence, here, we shall content ourselves with a description of the major principles and refer readers to works in the bibliography for additional elements -particularly regarding the application of such strategies. 

These strategies can themselves be subdivided into two categories those using global optimization and those which are applicable in real time. 

In the first case, we seek to minimize one or more criteria (for instance, we could cite the minimization of the hydrogen consumption for a fuel cell/battery vehicle) expressed in the form of mathematical function(s). In order to carry out this minimization, the dynamic programming method based on Bellman s principle of optimality [BEL 55]  

In the same spirit, it is also possible to use optimal control, which is based on Ponttyagin s minimum principle [PON 62], which aims to find the control signal which is capable of switching a dynamic system from one state to another, in the presence of constraints on the state or the control signals PEL 02 HAN 08]. 

The advantage to this type of approach hes in the fact that the solution obtained is theoretically optimal. The process of optimization takes account of the physical constraints on the components however, it may be vety costly in terms of computation time (and therefore often incompatible with the real-time requirement that is usually the rule in a hybrid storage system) and also requires prior knowledge of the profile of the load required over time, in order to be able to deliver an overall optimization. 

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The development of CHD is a lifelong process. Except in rare cases of severely elevated serum cholesterol levels, years of poor dietary habits, sedentary lifestyle, and life-habit risk factors (e.g., smoking and obesity) contribute to the development of atherosclerosis.3 Unfortunately, many individuals at risk for CHD do not receive lipid-lowering therapy or are not optimally treated. This chapter will help identify individuals at risk, assess treatment goals based on the level of CHD risk, and implement optimal treatment strategies and monitoring plans. 

For RPLC, the general strategy (Figure 3.10a) is less complex because no distinction between acidic and basic compounds is made. The optimization stage is also less complicated. In case of a baseline separation, the retention factor can be optimized based on the fact that a linear relationship is assumed between log k and the fraction... 

Table 12.2 Examples of technology-based strategies to optimize hit-to-lead process...

This paper presents an on-line model based level control of a batch reactor with reaction rate uncertainties. The analyzed chemical batch process is catalyzed by a catalyst which decomposes in the reactor therefore it is fed several times during the batch. The chemical reaction produces a vapour phase by-product which causes level change in the system. The on-line control method is based on the shrinking horizon optimal control methodology based on the detailed model of the process. The results demonstrate that the on-line optimization based control strategy provides good control performance despite the disturbances. 

The algorithm in Fig. 7.27 is characterized by two optimization loops. The inner loop describes the operating parameter optimization based on the strategies introduced before. When for one set-up (e.g. one column length) the optimized operating parameters have been found, a new set-up (e.g. another column length) has to be chosen, represented by the outer design parameter optimization loop. This proce-... 

This chapter gives an introduction to the concept of model predictive control and an overview of the concepts proposed for the control of simulated moving bed processes. Thereafter the benefits of a model-based optimizing control strategy for the example of a 6-column reactive SMB plant of pharmaceutical scale are presented. 

DICVOL91 has an indexing approach based on the dichotomy method, introduced by Louer and Louer. Shirley defined this method as probably the optimal exhaustive strategy in parameter-space . The original version of the program was written for orthorhombic and higher symmetry. Later, the method was extended to monoclinic and to triclinic symmetry. ... 

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