" With respect to what is shown by a conceptual model there are differences at least with respect to computer science, mathematics and logic. Mathematical models in one way or another establish a functional cohesion between entities such as input values and output values . Logical models establish an interpretation relationship between formulae and structures. Models in Computer Science are largely organizational in that they show how data, a cooperation between agents, the process of creating a response to an external stimulus, an algorithm, or similar is structured. The emphasis of organization that is apparent in many models of computer science appears to be a consequence of either of the following: (1) complexity issues need to be dealt with such that a functional cohesion actually can be evaluated. (2) a domain of individuals or universe of discourse has to be established and the individuals within that domain are supposed to be capable of being distinguished from each other by means of their condition in that organization or particular handles available to a user of that model. III. Model Railroad Product The original of a model may itself be physical or conceptual. It may be so, independently of the consistency of the model. "

" Developed between 1970 and 1973, it is a quantum field theory, and consistent with both quantum mechanics and special relativity. To date, almost all experimental tests of the three forces described by the Standard Model have agreed with its predictions. However, the Standard Model is not a complete theory of fundamental interactions, primarily because it does not describe gravity. The Standard Model The Standard Model contains both fermionic and bosonic fundamental particles. Fermions are particles which possess half-integer spin and obey the Pauli exclusion principle, which states that no fermions can share the same quantum state. Bosons possess integer spin and do not obey the Pauli exclusion principle. Informally speaking, fermions are particles of matter and bosons are particles that transmit forces. Backyard Model Railroad For a detailed description of the differences between fermions and bosons, see the article on identical particles. In the Standard Model, the theory of the electroweak interaction (which describes the weak and electromagnetic interactions) is combined with the theory of quantum chromodynamics. "