Last modified on 25 September 2008, at 16:08

Modeling from A to Z/Modeling principles

Modeling? What is that?Edit

Let us begin with a simple question? What exactly is meant by modeling? What do we mean by a model?

One way in which to answer these questions is to start with a simple example. The example we will begin with is the management of waste in the environment. It might be Nuclear waste. It might be office or home waste, such as the disposal of paper, glass, batteries, and so on.

In general, waste arrives at a processing plant. And the waste is all mixed up. The first important process is to separate this waste into its different constituent parts. We may call this the separation phase or the separation process. Such a phase has an input and an output. It will be convenient to imagine that the input is a container full of mixed waste and that the output is a collection of containers specific to each type of waste. So, for example, if the input container holds glass, paper and batteries, then it is reasonable to suppose that there are three[1] output containers.

In the modern Networked and Distributed Environment, one mode of improvement in the development and maintenance of both "industrial software with strong focus" such as in Waste Management, and "widespread-use software with collaborative focus" such as in Financial Market Analysis, is characterized by the rigor of both formal engineering techniques in the modeling of critical kernels, and in the ontological grounding of all key concepts and their properties.

Same-shape modelsEdit

Let us imagine that you build a model of an airplane. It has a body, wings, cockpit, wheels. And some other bits. The key parts are the body, wings, and so on. You are pleased with your model. It can not fly of course. But there are days when you sit still and stare at it and wonder and dream.

You are staring out the window. It is a nice day, blue sky, some white clouds floating. Suddenly a bird flies by, black in color. It is not quite the apple falling on the head kind of experience, but close enough. You say to yourself. „Why not build a model of a bird?“ Both have wings. You sketch out the wings. Both have places for eyes and so on. For the bird it will be called the head. The airplane has a cockpit instead. After a while you draw a table:

Design for flight thing
Name Airplane Bird
body Airbus body[2] Pigeon body[3]
observation platform[4] cockpit Eagle head
wings Boeing wings[5] Albatross wings
stuff for being on ground[6] wheels Crow feet

It is easy to see the correspondences between the airplane and the bird. It is not so easy to see why these particular birds have been chosen. Can you think of a good reason? Would you make a different choice. If yes, what reasons would you give for your choice?

Development of modelsEdit

One of those quiet days when you have time to yourself and perhaps you are daydreaming, staring out the window, an idea lands. „What do I need to add to the model to make it fly?“, you say to yourself.

To ask such a question is to take oneself right back to the beginnings of the search for flight. That birds should give directions is only natural. However, for the flight of man, many solutions have been found. What are they? Where did the ideas comes from? Who had the ideas? Where can we find information of this?

But the birds did not give the inspiration for the balloon nor the helicopter. Where do you think these ideas came from?

NotesEdit

  1. This simple example shows how easy it is to get it wrong. One must always take into account the unexpected. For example, a rat might have decided to take up residence in the input container. It is then big surprise for the computer system to know whether the rat is glass or paper or battery! The solution is to have four output containers. The fourth one is the catch-all container. Perhaps you have now become suspicious and wary? Perhaps, we need a fifth output container? Can you think of a reason reason why?
  2. You want to show the shape of the body to your friends. Which one do you have in mind? Maybe it is the new Airbus A380?
  3. You choose the Pigeon body you like.
  4. This is a very complicated and long phrase. It is invented to fit the general idea of "a place to see from". Maybe you can think of a better phrase?
  5. Do you dream of the Boeing 787 Dreamliner?
  6. Maybe a better generalization of wheels and feet is "landing apparatus" or "standing apparatus"? You can see just how difficult it is to find phrases to cover the meaning of wheels (for aircraft) and feet (for bird). Have you a better suggestion?

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