<Li> Constructs which are concepts that form the vocabulary of a domain . They constitute a conceptualization used to describe problems within the domain and to specify their solutions . </Li> <Li> A model which is a set of propositions or statements expressing relationships among constructs . </Li> <Li> A method which is a set of steps (an algorithm or guideline) used to perform a task . Methods are based on a set of underlying constructs and a representation (model) of the solution space . </Li> <Li> An instantiation is the realization of an artifact in its environment . </Li>

Types of information systems in system analysis and design