It System Management - Part 2 Coping with Complexity

2. COPING WITH COMPLEXITY

1) ENTERPRISE ARCHITECTURES

An Enterprise Architecture Framework (EA) is a major instrument for coping with complexity.

a) What is a "modeling view"? What is a "phase" in this regard? Please explain the meaning (the purpose) of views and phases within the context of EA.

In just a short time, most businesses have gone from complicated to complex: They contain numerous diverse, interdependent parts. This makes managers' jobs much more difficult [Gökçe Sargut and Rita Gunther McGrath, "Learning to Live with Complexity" P5]. How to coping with the complex environment, we are looking for instrument to simplify and visualize the complicated picture. Enterprise modeling view is to help better understanding of business process and business structures. Abstraction is the basic concept of modeling and Business process is a continuous series of enterprise activities, undertaken for the purpose of creating output [Scheer, Habermann, Thomas, "Enterprise Modeling", Chapter 9, P281, 286]. The Modeling views are: Function views, organization views, data views, output views and process views according to Habermann. See figure 2 ARIS Phases [Scheer, Habermann and Thomas, "Enterprise Modeling", P297].

The Phase is a description of main tasks in the ARIS model which describes the entire procedure from the requirements definition to the operation and maintenance of IT-applications. Each phase consists of different main tasks in course of the development process, e.g. phase 2, the requirements definition means the description of

- process & functional requirements

- a data model ("entity relationship model),

- systems requirements.

It is important to describe on the one hand side the process & functional requirements as well as the data model in business language, and on the other hand side the systems requirements in IT expert language. To describe the process & functional requirements it is necessary to use the "Use-Case-Concept", which means to describe each business requirement in a use-case. That leads to a hierarchy process, sub-process, IT-function and Use Cases (the deepest level). For the requirements definition standards like ITIL and DIN 69905 are useful.

Regarding the modeling view: ARIS (also Bonapart, Innovator and iGrafx as other examples for such modeling tools) as a modeling tool allows building up all phases of the entire development process within ARIS. The user has with ARIS the opportunity to look in each model like

- Process model

- Organizational model

- Data model as well as the CRUD matrix (Create Read, Update & Delete - the

data management life cycle)

- System Design

- System Architecture

For instance in the process model you can use different views with different abstraction levels into the process model like

- the entire process chain as one picture

- the overview about all sub-processes in a picture

- the overview of the sub-process hierarchy, e.g. with 4 or 5 levels of sub-processes

- the detailed overview of a sub-process

- the description of each tasks within a sub-process

- the description of roles and its responsibilities

- etc.

b) What is a "modeling method"? Please describe the general relationship between method,