Process-data diagram

The four gray boxes depict the four main implementation phases, which each contain several processes that are in this case all sequential.

A special kind of sequential activities are the start and stop states, which are also illustrated in Figure 1.

The example is taken from the requirements capturing workflow in UML-based Web Engineering.

The solution to this modeling issue is to divide the main activity in different parts.

In Figure 4 an example is illustrated, which clarifies the necessity to be able to model unordered activities.

The example is taken from the requirements analysis workflow of the Unified Process.

The main activity, “describe candidate requirements”, is divided into two parts.

The second part consists of four activities that do not need any sequence in order to be carried out correctly.

The reason for carrying out these activities concurrently is that defining the actors influences the use cases greatly, and vice versa.

Based on this study, the decision is taken whether to do an extensive requirements elicitation session or not.

They are connected with a dotted arrow to the produced artifacts, as is demonstrated in Figure 9.

It concerns an example from the orientation phase of complex project in a WebEngineering method.