Part Four Process Oriented Modeling and Analysis 8 IDEF3 Process Capture Method Abstract IDEF3 is one of IDEF series modeling methods. It is applied to business process modeling and analysis. IDEF3 was originally developed for concurrent engineering. Recently, it is used for business process reengineering and business process management. The syntax and semantics of IDEF3 for business process modeling are introduced in this chapter. The structured approach for IDEF3 model development is also discussed. 8.1 Introduction to IDEF3 The IDEF3 Process Description Capture Method describes sequences of activities. Its primary goal is to provide a structured method to describe the operation of a particular system or organization. IDEF3 was designed to [1]: • Collect, describe, store, manage, and reuse process information. • Be used in engineering, manufacturing, logistics, business systems and even government operation areas. • Model a small- and large-scale system at both high abstract and high detailed levels. • Be integrated with other IDEF methods. • Be easy to learn and use by stakeholders. Benefits of IDEF3 are cost savings, time reducing, quality improvement, organizational capability improvement, and continuous improvement of organizational mechanism and business process. IDEF3 has been used to [1]: • Identify business processes in various areas. • Provide an implementation-independent specification for human-system interaction. • Define business process management and change management. • Document the decision procedures of an enterprise or a government department. • Be a useful interview supporting tools. • Develop real-time control software by providing a mechanism to clearly define facts, decision points, and job classifications. • Define the behavior of workflow management systems and applications. 160 8 IDEF3 Process Capture Method • Design new processes rapidly. • Speed the development of high quality IDEF0 function models. • Speed the development and validation of simulation models. • Find redundant and/or non-value-added activities for business process optimization. • Support Business Process Re-engineering and continuous process improvement. There are several versions of IDEF3 [1, 2, 3] with distinct syntax and semantics. The latest version introduces concepts on object from IDEF5 Ontology Capture. Following introduction is based on the latest version technique report. IDEF0, IDEF1X and IDEF3 are the three main modeling methods in The IDEF modeling family. They are respectively function oriented, data oriented and process oriented system design and analysis methods. KBSITM distinguished their purposes, concepts and so forth in Table 8.1. Table 8.1. Comparison among IDEF0, IDEF1X, and IDEF3 IDEF0 IDEF1X IDEF3 What you do What you need to know How you do it Functional dependencies Information management or Precedence and cause-&- database design effect Used to “target” activities Information or data require- Reduce cycle time that need improvement ments A modeling method Analysis method/design A description method method 8.2 Syntax and Semantics of IDEF31 IDEF3 uses a series of concepts, symbols, and rules for business process descriptions. It also provides a mechanism to develop and optimize models for business process analysis and management. 8.2.1 Basic Concepts of IDEF3 An IDEF3 process model describes the events network in a scenario. IDEF3 descriptions include two different views: Process Centered View and Object Centered View. They are cross-referenced to each other to represent complex process descriptions. Scenario is the key concept of IDEF3 and is used as the basic organizing framework for IDEF3 Process Descriptions. A scenario is a set of situa- tions that describe a typical kind of problems, or the environment that a 1 The structure, content, and examples of the section reference the technical report “Concurrent Engineering (IICE) IDEF3 Process Description Capture Method Report” by KBSI. 8.2 Syntax and Semantics of IDEF3 161 process occurs. Scenarios establish the focus and boundary conditions of a description. Using scenarios, stakeholders can describe what they know on an ordered sequence of activities within the context of a given scenario or situation. Scenarios also help to organize process-centered knowledge. The primary role of a scenario is to form the context of an IDEF3 Process Description [1]. Scenario names often take the form of a verb or verb phrase and a verb that functions as a noun. An IDEF3 Process Description is developed based on two strategies: process-centered strategy and object-centered strategy. The process-centered strategy focuses on processes and their temporal, causal, and logical relations within a scenario. The object-centered strategy focuses on objects and their state change behavior in a single scenario or across multiple scenarios [1]. Both strategies use the basic elements of the IDEF3 language, as shown in Fig. 8.1. An IDEF3 Process Description may contain zero or more process diagrams and zero or more object diagrams. The scenario concept is used to organize both the process-centered and object-centered views. 8.2.2 Process Diagram Process diagrams are the most familiar and widely used components of the IDEF3 method. These diagrams provide a visualization mechanism for process-centered descriptions of a scenario. The graphical elements of process diagrams include Unit of Behaviors (UOBs), precedence links, junctions, ref- erents, and notes. Referents and notes provide associations between process diagrams and object diagrams. (1) Unit of Behavior A UOB describes a type of situation or activity. Its instance is an occur- rence of the UOB. When one captures “what’s going on” in a given system, that does not mean what in fact happened in the system at particular time, but rather what happens in general that can occur again and again in the sys- tem [1]. A process description represents the types of situations (processes, functions, etc.) that can occur in the system and the logical and temporal constraints that combine them together [1]. A UOB is represented by a special kind of box with a unique label, as shown in Fig. 8.1. (2) Link A link is the glue that connects UOBs to form representations of dynamic processes. A link is drawn to start or end on a UOB or junction symbol. There are two basic types of links used in IDEF3 process diagrams: prece- dence link and dashed link. Precedence links describe temporal precedence relations between instances of one UOB and those of another. They are the most widely used link and 162 8 IDEF3 Process Capture Method Fig. 8.1. Symbols used for IDEF3 8.2 Syntax and Semantics of IDEF3 163 are denoted by a solid arrow, sometimes with an additional marker attached to the stem of the arrow, as shown in Fig. 8.1. Dashed links carry no predefined semantics. They are often used as user- defined links or relational links. This type of link points out a possibly constraining relationship between two UOBs [1]. All links have an elaboration and unique link numbers. Displaying link numbers on the process diagrams is optional [1]. PL (for “precedence link”) and DL (for “dashed link”) are prefaced for Precedence links and Relational links. Link numbers are assigned sequentially. (3) Junction Junctions provide a mechanism to define the logic of process branching. They simplify the capture of timing and sequencing relationships between multiple process paths. IDEF3 diagrams involve four kinds of branch points [1]: • Points at which a process branches into multiple parallel sub-processes; • Points at which a process branches into multiple alternative sub-processes; • Points at which multiple parallel sub-processes join into a single line; • Points at which multiple alternative sub-processes join into a single line. IDEF3 includes four general types of junctions to express the four gen- eral kinds of branch points. The first two kinds are expressed by fan-out junctions: Conjunctive fan-out junctions represent points of branch involv- ing multiple parallel sub-processes, while disjunctive fan-out junctions repre- sent points of branch involving multiple alternative sub-processes. The last two kinds of branch points are expressed by fan-in junctions: conjunctive fan-in junctions represent points of convergence involving multiple parallel sub-processes, while disjunctive fan-in junctions represent points of conver- gence involving multiple alternative sub-processes [1]. There is one type of conjunctive junction, or AND junction, indicated by “&”. There are two types of disjunctive junctions: inclusive and exclusive junctions, or OR and XOR junctions. The classification of junctions is described in Fig. 8.2. Fig. 8.2. Classification of junctions 164 8 IDEF3 Process Capture Method A fan-out AND junction means that there will be UOBs that are (im- mediate) successors of the junction. If a synchronous AND junction is used, then, those UOBs must all start at the same time. Similarly, the meaning of a fan-in AND junction is that there will be UOBs that are (immediate) predecessors of the junction. And if a synchronous AND junction is used, then, those UOBs must all end at the same time [1]. Junctions represent branch points in a general process as shown in Fig. 8.3. To make unambiguous references to the junctions, junction reference num- bers are attached near relative junctions, which start with the letter J. Two distinct junctions have different junction numbers. Fig. 8.3. Precedence links connecting to junctions (4) Referent Referents enhance understanding, provide additional