OOADUML COMPLEX SYSTEMS   Attributess of a complex systems    Hirarchy Primitive component is arbitrary Intra component linkages are stronger than inter component linkages complex systems sub systems in different combination computer system evoluated from simple system                                                         Some basic concepts  strategies in the study of systems  Abstraction We have developed an exceptionally powerful technique for dealing with complexity We abstract from it Unable to master the entirety of a complex object we choose to ignore the inessential details dealing instead with the generalized idealized model of the object Wulf in Shaw   Formality Rigor at each stage in the development of a system   Divide and conquer Divide a complex problem into a set of simpler problems that can be solved   Hierarchical ordering Order the simplification of the problem in divide  conquer in hierarchies   Cohesion  coupling Modularise the system such that interactions within components cohesion is maximised and interactions between components coupling is minimised This way the impact of errors when they arise is localised and does not cascade through the system Diagnosis of offending components is also made easier   Information hiding Each module or subsystem must have available to it just the information that is needed by it   Conceptual integrity Consistency in design   Completeness Ensuring that the design meets all the specifications   Logical independence Emphasis on the statement of system objectives in terms of logical functions independent of physical implementation   Correctness  Efficiency Correct in the sense that the design meets all the user requirements Efficient in that the system accomplishes the objectives with minimum computing resources