modelling techniques using idef
DESCRIPTION
Modelling techniques are used for estimations as well as improvement of any system under study. This presentation describes how to USE idef language for the same purpose.HOUSTONTRANSCRIPT
Integrated Definition (IDEF) Modeling Techniques
Ozgun DemiragAndy JohnsonDima NazzalYen-Tai Wan
Outline
What is IDEF?IDEF Family: Overview Examples Strengths and Weaknesses
Rasmussen - Design Maps Definition
What is IDEF?
Definition: IDEF is the common name referring to classes of enterprise modeling languages.Objective: IDEF is used for modeling activities necessary to support system analysis, design, improvement or integration.Originally, IDEF was developed to enhance communication among people trying to understand the system. Now, IDEF is being used for documentation, understanding, design, analysis, planning, and Integration.
IDEF History
In the 1970’s, IDEF0 originated in the U.S. Air Force under the Integrated Computer Aided Manufacturing(ICAM) program from a well-established graphical language, the Structured Analysis and Design Technique (SADT).
IDEF Family
IDEF Family of Methods: IDEF0: for Function Modeling
(purpose:description) IDEF1: for Information Modeling.
(purpose:description) IDEF1x: for Data Modeling. (purpose:design) IDEF3: for Process Modeling.
(purpose:description) IDEF4: for Object-Oriented Design.
(purpose:design) IDEF5: for Ontology Description Capture.
(purpose:description)
IDEF0- Function Modeling Method
IDEF0 models the decisions, actions, and activities of an organization or system, in order to communicate the functional perspective of a system.IDEF0 models are created as one of the first tasks of a system development effort because they describe: the functions that are performed, what is needed to perform those functions,
IDEF0 was released as a standard for Function Modeling by the Computer Systems Laboratory of the National Institute of Standards and Technology. (1993)
IDEF0- Function Modeling Method
Syntax: Context Diagram: is a model of the function
at the highest level of inputs, controls, outputs, and mechanisms
Mechanisms
Function Name
Controls
Inputs Outputs
• Inputs: items that trigger the activity• Controls: guide or regulate the activity• Mechanisms: systems, people, equipment used to perform the activity• Outputs: results of performing the activity
IDEF0- Function Modeling Method
Decomposition Diagram: links together the context diagrams
IDEF0- Function Modeling Method
STRENGTHS The model has proven effective in detailing the
system activities for function modeling. IDEF0 models provide an abstraction away from
timing, sequencing and decision logic. However, it is easy to use IDEF0 for modeling activity sequences whenever needed. (Order the activities from left to right in the decomposition diagram).
Provides a concise description of systems, by using the ICOMS. (Inputs, Controls, Output, Mechanism)
The hierarchical nature of IDEF0 allows the system to be easily refined into greater detail until the model is as descriptive as necessary for the decision making task.
IDEF0- Function Modeling Method
WEAKNESSES IDEF models might be so concise that only the
domain experts can understand. IDEF models are sometimes misinterpreted as
representing a sequence of activities. The abstraction away from timing, sequencing and
decision logic leads to comprehension difficulties for the people outside the domain.
IDEF0- Function Modeling Method
EXAMPLE (source: [4])
IDEF1- Information Modeling Method
IDEF1 is a method for both analyzing and communicating the structure and semantics of information within a system.IDEF1 models are used to:
Identify what information is currently managed in a real-world system, both automated system components, and non-automated objects (e.g. people).
Identify the rules for managing the information. Identify deficiencies in the current management of the
information. Specify what information will be managed in a TO-BE
implementation. (TO-BE implementation: Design of the functional architecture)
IDEF1- Information Modeling Method
Main IDEF1 Concepts Entities: Represent the information
maintained in a system about the real-world objects Distinguishing properties:
Persistent May be individuated
Attributes: Key Non-key
Relations: Association between entities
IDEF1- Information Modeling Method
IDEF1- Information Modeling Method
STRENGTHS IDEF1 requires active participation of the
information users, which serves to accurately model where and how the information is used and managed.
An effective method for documenting the informational requirements of an enterprise, providing a foundation for database design.
IDEF1 enforces a modularity that eliminates the incompleteness, imprecision, inconsistencies, and inaccuracies found in the modeling process.
IDEF1x- Data Modeling Method
IDEF1X is a method for designing relational databases. IDEF1X Model: Graphical and Textual depiction of “What must I know to do what I do?” IDEF1X is most useful for logical database design after the information requirements are known and the decision to implement a relational database has been made.IDEF1X was released as a standard for Data Modeling by the Computer Systems Laboratory of the National Institute of Standards and Technology. (1993)
IDEF1x- Data Modeling Method
EXAMPLE (ref:[2])
IDEF1x- Data Modeling Method
EXAMPLE (ref:[2])
IDEF1x- Data Modeling Method
STRENGTHS Powerful tool for data modeling. IDEF1X don’t have numerous variants, unlike ER. Depicts the rules governing the management of
information. Used to validate the concepts in the associated IDEF0
model. Helps to discover underlying causes for problems.
WEAKNESSES The modeler must be experienced in order to create
good models. Not suited to serve as an AS-IS analysis tool.
IDEF1 (information Model) vs. IDEF1x (Data Model)
Information Model Data Modelfocuses on:
Information collected, stored, and managed by the organization
Logical relationships within the organization reflected in the information
focuses on: Actual data elements in a
relational database Representation &
structure of the data
used for: Problem identification Requirements definition Information system design
used for: Logical design of
databases & applications Physical design of
database implementation
IDEF3- Process Description Model
“IDEF3 is a mechanism for collecting and documenting processes.… IDEF3 captures the behavioral aspects of an existing or proposed system.” (temporal information, including precedence and causality relationships associated with enterprise processes.)“The resulting IDEF3 descriptions provide a structured knowledge base for constructing analytical and design models. (unlike simulation languages that build predictive mathematical models, IDEF3 builds structured descriptions.)”“These descriptions capture information about what a system actually does or will do and also provide for the organization and expression of different user views of the system.”
Sounds
Familiar !
Source: http://www.idef.com/idef3.html
IDEF3- Process Description Model
The development of an IDEF3 Process Flow Description consists of expressing facts, collected from domain experts, in terms of five basic descriptive building blocks.
ActivityDenoted as arcs
LogicDenoted as junction boxes
Unit of BehaviorDenoted as boxes
Object StateDenoted as circles
State TransitionDenoted as arcs
Process Description Diagram
Object State Transition Network
Source: http://www.idef.com/idef3.html
IDEF3- Process Description Model
Organizing Structure: ScenarioA scenario can be thought of as a recurring situation, a set of situations that describe a typical class of problems addressed by an organization or system, or the setting within which a process occurs.
ExampleScenario:Parts enter the shop ready for the primer coat to be applied. We apply one very heavy coat of primer paint at a very high temperature. The paint is allowed to dry in a bake oven after which a paint coverage test is performed on the part. If the test reveals that not enough primer paint has been sprayed on the surface of the part, the part is re-routed through the paint shop again. If the part passes the inspection, it is routed to the next stop in the process.
Source: http://www.idef.com/idef3.html
IDEF3- Process Description Model
Process Description Diagram of the Example
Source: http://www.idef.com/idef3.html
IDEF3- Process Description Model
Object State Transition Network of the Example
Source: http://www.idef.com/idef3.html
IDEF3- Process Description Model
Other Example
Source: (Zakarian & Kusiak, 2001)
IDEF3- Process Description Model
Other Example
Source: (Bosilj-Vuksic’s , 2000)
IDEF3- Process Description Model
Discussion The statement of IDEF3 sounds like …
Domain
Insta
nceModel
Schema
ProcessReference
Model
Is IDEF3 a good way to represent processreference models ?
Source: http://www.isye.gatech.edu/~lfm/8851/ISyE8851.html
IDEF4- O-O Design MethodIDEF4 method is designed to assist in creating object-oriented programming software.IDEF4 provides a framework for navigating an evolving object-oriented design. IDEF4 divides the object-oriented design activity into discrete chunks. A graphical syntax highlights the design decisions that must be made and their impact on other perspectives of the design. IDEF4 model consists of two submodels, the class submodel and the method submodel. These two structures capture all the information represented in a design model.
IDEF4- O-O Design Method
IDEF5 - Ontology Description Method
An ontology is a domain vocabulary complete with a set of precise definitions or axioms that constrain the meanings of the terms sufficiently, to enable consistent interpretation of the data that use that vocabulary.General ontology construction steps:1. catalog the terms;2. capture the constraints that govern how those terms can be used to make descriptive statements about the domain; and3. build the model.
IDEF5 - Ontology Description Method
The IDEF5 ontology development process consists of the following activities.
Data Collection of raw data needed for ontology development.
Data Analysis to facilitate ontology extraction.
Initial Ontology Development to develop a preliminary ontology from the data gathered.
Ontology Refinement and Validation.
REALITY
INTERVENE
COMPUTATIONALMODEL
SYNTHETICMODEL
NORMATIVEMODEL
PLANNINGMODEL
OB
SE
RV
E
NARRATIVEMODEL
SYMBOLICMODEL
The “modeling
cycle”
I DEF
Rasmussen - Design Maps Definition
Map 1: Domain, tasks, and user in contextMap 2: Knowledge baseMap 3: Road maps for navigationMap 4: Knowledge representation in designMap 5: Display composition
Side by Side Comparison
Map 1: Domain, tasks, and user in contextMap 2: Knowledge baseMap 3: Road maps for navigationMap 4: Knowledge representation in designMap 5: Display composition
IDEF0 (IDEF Function Modeling)IDEF1 (IDEF Information Modeling)IDEF1X (IDEF Data Modeling)IDEF3 (IDEF Process Modeling)IDEF4 (IDEF Object-Oriented Design)IDEF5 (IDEF Ontology Description Capture)
Rasmussen Map 1 compared to IDEF0- Diagram
Decomposition Diagram: links together the context diagrams
Key
Both require an expert in the field to use and understand the model This is a result of the method being a
very high level concept and developing the details for any single application is not a trivial matter
Advantage of IDEF
IDEF 5 attempts to incorporate the vocabulary of the specific application
References
Colquhoun, G.J, Baines, R.W, Crossley, Roger, A State of the Art Review of IDEF0, International Journal of Computer Integrated Manufacturing, Vol. 6, No. 4, 1993, pp. 252-264.
(2) Introduction to IDEF Methodology, USACE LCM Manager’s Guide Version-2 http://www.usace.army.mil/ci/impolicy/lcmis/lcma3.pdf
(4) Bosilj-Vuksic’s paper (http://oliver.efzg.hr/~vbosilj/iceis2000.pdf)