Enterprise Systems Modeling EGN 5623 Enterprise Systems Optimization Fall, 2012

Information systems modeling tools IDEF ◦IDEF0 (activities) ◦IDEF1x (information) ◦IDEF2x (dynamics) OMT ◦Functional model ◦Object model ◦Dynamic model

IDEF Concept (1) IDEF (ICAM Definition) ◦Developed by the US Air Force Integrated Computer Aided Manufacturing (ICAM) Programs in 1981 ICAM Objective ◦To develop structured methods for applying computer technology to manufacturing and to better understand how best to improve manufacturing productivity

IDEF Concept (2) IDEF0 ◦An activity model of a manufacturing system and environment IDEF1 ◦An informational model of the system and environment IDEF2 ◦A dynamic model to describe time-varying system behavior

IDEF Concept (3) IDEF Methodology ◦Modeling process and tools, leading to creation of the three IDEF models  IDEF0 (activities)  IDEF1x (information)  IDEF2x (dynamics) Commercial IDEF software tools ◦Design/IDEF by Meta Software Company ◦AI0WIN by Knowledge Based Systems Inc.

OMT Concepts (1) Object modeling technique (OMT) “Object-oriented” means: ◦Software organized as a collection of discrete objects that incorporate both data structure and behavior, in contrast to conventional programming in which data structure and behavior are only loosely connected. OMT Methodology (in stages): ◦system analysis, ◦system design, ◦Object (implementation) design, and ◦implementation.

OMT concepts (2) - common themes Synergy (i.e., shifting focus from coding technique to packaging, based on consistent ◦identity, ◦classification, ◦polymorphism, and ◦inheritance Abstraction, Encapsulation, Combining data and behavior, Sharing (inheritance of data structure & behavior among subclasses) Emphasis on object structure (not procedure structure),

OMT Concepts (3) - Synergy Identity ◦Data is quantized into discrete, distinguishable entities called objects Classification ◦Objects with the same data structure (attributes) and behavior (operations) are grouped into a class  An operation is an action or transformation that an object performs or is subject to. polymorphism ◦The same operation may behave differently on different classes.  A specific implementation of an operation by a certain class is called a method. Each operation may have multiple methods implementing it. inheritance ◦The sharing of attributes and operations among a hierarchy of object classes

OMT Models (4) 3 OMT models used to describe a system: ◦Object model  describing the objects in the system and their relationships; ◦Dynamic model  describing the interactions among objects in the system; and ◦Functional model  describing the data transformation of the system. Their relationship ◦The object model describes what changes (or transforms) before when (dynamic model) or how (functional model) it changes.

OMT Functional Model (5) It describes the data value transformations within a system. The functional model contains data flow diagrams. ◦A data flow diagram is a graph whose nodes are processes (activities) and whose arcs are data flows.

OMT Object Model (6) It describes the static structure of the objects in a system and their relationships. The object model contains object diagrams. ◦An object diagram is a graph whose nodes are object classes and whose arcs are relationships among classes.

OMT Dynamic Model (7) It describes the aspects of a system that change over time and is used to specify and implement the control aspects of a system. The dynamic model contains state diagrams. ◦A state diagram is a graph whose nodes are states and whose arcs are transitions between states caused by events.

Relationship between the two techniques & among the three models IDEF0/functional model ◦The input to an activity is usually through a user interface for data entry ◦The output from an activity is usually a user interface for a report, though the output may be a write/update to a database. IDEF0’s ◦ICOM  Material is an input object.  Product/process data are output objects.  Rules/regulations and SOPs are constraints. Technical precedence is a constraint  Resources/tools and methods are a mechanism. IDEF1/object model ◦The collection of the ICOM of an IDEF activity model constitutes an inclusive foundation for the object model. IDEF2/dynamics model ◦Each object requires a state diagram to define/govern its life-cycle behavior. ◦A triggering event is associated with each transition from one state to another. One state may transform to multiple states, depending on the triggering event.

Relationship between the two methods and among the three models IDEF0/functional model ◦The input to an activity is usually a user interface for data entry ◦The output to an activity is usually a user interface for a report, though the output may be a write/update to a database. ◦ICOM  Material is an input object.  Product/process data are output objects.  Rules/regulations and SOPs are constraints.  Resources/tools and methods are mechanisms. IDEF1/object model ◦The collection of the ICOM of an IDEF activity model constitutes an inclusive foundation for the object model. IDEF2/dynamics model ◦Each object requires a state diagram to define/govern its life-cycle behavior. ◦A triggering event is associated with each transition from one state to another. One state may transform to multiple states, depending on the triggering event.