Static model

One significant limitation of such reductionistic models lies in their inability to reveal the dynamic nature of the systems they portray. These models describe artificial conservative states with no revelation of dynamic transactions and alterations of states. Of course the illusion of movement can be graphically fabricated by collectively changing the coordinate frame, but the transactions within the system are still unaltered. While useful information may be derived from such models, it is imperative that their genesis be well known to the drug designer. 

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There are available from experiment, for such reactions, measurements of rates and the familiar Arrhenius parameters and, much more rarely, the temperature coefficients of the latter. The theories which we use, to relate structure to the ability to take part in reactions, provide static models of reactants or transition states which quite neglect thermal energy. Enthalpies of activation at zero temperature would evidently be the quantities in terms of which to discuss these descriptions, but they are unknown and we must enquire which of the experimentally available quantities is most appropriately used for this purpose. 

Here we have assumed that the temperature 9 does not depend on Let the plate be isotropic and aij = Pij = (5 %, where 5 is a constant. Then (1.33) gives the quasi-static model of a thermoelastic plate ... 

The interaction between ligands and their receptors is clearly a dynamic process. Once the static model of ligand-receptor interaction has been obtained, the stability of ligand-receptor complexes should be evaluated by means of molecular dynamics simulations [18]. 

Generally, the models used for simulation of living polymers can be divided roughly into two classes, focused on static or dynamic properties of the LP or GM. The static models are mainly designed to study equilibrium conformational properties of the polymer chains, critical behavior at the polymerization transition, and molecular weight distribution... 

From the qualitative analysis, Chan found that students mental models could be categorized into three types initial, synthetic, and scientific mental models (Fig. 11.4). The initial model refers to the static model, which had only solute dissolved into the solution and then stopped at the saturation point. The synthetic model refers to the coexistence of two models the unidirectional model and... 

The configuration of a system in which percolation may occur is classically treated as one in which the ingredients do not move. Considerable work has been devoted to these static models, leading to numerical solutions of the critical concentrations and cluster sizes associated with a percolation threshold. 

The bulk chemical commodity producing companies (e.g., refineries, petrochemicals) have been practicing this philosophy for some time, using dynamic models to contain operational variability through feedback controllers, and employing static models to determine the optimal levels of operating conditions (Lasdon and Baker, 1986 Garcia and Prett, 1986). 

The most important experimental task in structural chemistry is the structure determination. It is mainly performed by X-ray diffraction from single crystals further methods include X-ray diffraction from crystalline powders and neutron diffraction from single crystals and powders. Structure determination is the analytical aspect of structural chemistry the usual result is a static model. The elucidation of the spatial rearrangements of atoms during a chemical reaction is much less accessible experimentally. Reaction mechanisms deal with this aspect of structural chemistry in the chemistry of molecules. Topotaxy is concerned with chemical processes in solids, in which structural relations exist between the orientation of educts and products. Neither dynamic aspects of this kind are subjects of this book, nor the experimental methods for the preparation of solids, to grow crystals or to determine structures. 

Sherrington (S10) has presented a static model of the granulation loop operating in the snowballing mode. The model combines the solution phase theory in Eq. (106) with the material balance across the granulator. The recycle ratio defined as recycle/raw solid feed, is given by... 

We can see now why the static model of Lewis with four electron pairs in a tetrahedral arrangement is so useful even though electrons are in rapid motion and do not occupy fixed positions. Each electron pair occupies a reasonably well localized domain, and four domains have a tetrahedral arrangement. 

A dynamic model with tunneling hydrogen (Joos etal., 1980) and a static model (Broeckx et al., 1980 Ham, 1988) have been proposd to explain the experimental findings. Space here is far too limited to discuss all the features of the two models and their relative merits. Suffice it to state that both models can explain certain properties of this complex. At the same time, both models have some shortcomings. The static model, which is based on a trigonal complex, is clearly too limited and cannot explain all... 

Analysts Mainstream OO analysis is difficult if you are used to structured methods. In some ways our approach is simpler You explore system-level scenarios, describe the system operations, capture terms you use in a static model of the system, and then formalize operations using this model. In other ways, our approach is more difficult we do not like fuzzy and ambiguous analysis documents, so some of the precision we recommend may be a bit unfamiliar for early requirements activities. Read Chapters 1 through 7, 9, and 13 through 15. 

This use of the associations, or a static model, to provide a vocabulary for the actions, or a dynamic model, gives a clear guide as to what objects you need those that are required to describe the actions. 

Gathering all the specs for the actions the system is required to take part in and the static models needed to draw snapshots for those specs, we compile a formal functional requirements model. Notionally it looks like the drawing in Figure 1.20. 

The static model is a hypothetical picture created for the purpose of explaining the system s externally visible behavior to its users. There is no absolute mandate on the designer to implement it exactly with classes and variables that directly mirror the types and associations in the spec. For one thing, there are usually complications such as managing a data-... 

Each of the components18 performs only some of the system s functions and includes only part of its state, which we can see by drawing the static models (see Figure 1.26). 

The interchange models—how Clients, Instructors, and so on are represented. This is done with static models. 

Chapter 2, Static Models Object Attributes and Invariants, describes how attributes abstract variations in the implementation of object state. Chapter 3, Behavior Models Object Types and Operations, describes how operation specifications describe externally visible behavior of an object, independently of algorithmic and representation decisions. 

Templates abstract similar models. We have seen them used to simplify a static model and to define component connectors (see Section 1.5). 

The static part deals with the information we have about the state of an object at ary given moment. At a given level of time granularity, we describe static attributes, relationships, and constraints between objects. Chapter 2, Static Models Object Attributes and Invariants, is about modeling static aspects using abstract attributes. 

Models can be divided into static, dynamic, and interactive parts dealing with, respectively, what is known about an object at any one moment, how this information changes dynamically with events, and how objects interact with one another. This chapter discusses the static part of a model, in which you characterize the state of an object by describing the information known about it at any point in time. It uses the type model diagram to capture the static model and snapshot diagrams to show instantaneous configurations of object state. 

The first section is an overview of what a static model is about. Section 2.2 introduces objects, their attributes, and snapshots and distinguishes the concept of object identity from object equality. The attributes that model an object s state can be implemented in very different ways. Section 2.3 outlines some implementation variations using Java, a relational database, and a real-world implementation. 

Whereas snapshots illustrate specific sample situations, what we need to document are the interesting and allowed states the objects, links, and labels that will be used in the snapshots. This documentation is the purpose of a static model, which comprises a set of type diagrams and surrounding documentation. 

Static models have different uses in different parts of the development life cycle. If we decided to start from scratch in providing software support for a hotel s booking system, our analyst s first deliverable would be a description of how the hotel business works, and a type model would be an essential part of it, formalizing the vocabulary. Later in the life cycle, the objects in the software can be described in the same notation. 

The strict answer is that the static model, without actions, does not tell us enough. The only real test is whether the system we re modeling behaves (responds to actions) as a client would expect from reading the whole model, actions and all the static part merely sets a vocabulary for the rest. This strict view allows some implementations to conform that might not otherwise. For example, suppose we never specified any actions that used the balance. By the retrieval function rule, we would still have to implement that attribute even though it would make no perceptible difference to clients whether or not it was implemented. 

So far, we have used static modeling to describe the objects that exist in some world, but we can also use a static model to describe the state of a complete system. We said at the beginning of this chapter that this was the ulterior motive for making a static model. Figure 2.18 shows a model of a simple type. 

A static model describes the state of the business or the component(s) we are interested in. Each concept is described with a type, and its state is described with attributes and associations these lead in turn to other types. The formally defined types are related to the users world in a dictionary. 

The main purpose of a static model is to provide a vocabulary in which to describe actions, which include interactions in a business, between users and software, or between objects inside the software. We use snapshots to represent specific situations, and that helps to develop the static model (see Figure 2.20). Snapshots are an important thinking... 

The static model of an object s internal state and of information exchanged in the operation requests, using attributes, associations, and invariants... 

Specifications of the effects of the actions on the component, using the vocabulary provided by the static model... 

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