EDUCE Overview Copyright 2009 Nikolas S. Boyd.
All rights reserved.

Usage Description

Intent

Describe solution users, their business interests and objectives (ends), and their activities (means) to achieve those objectives.

Motivation

Usage descriptions focus on the interactions between participants engaged in an exchange of information, goods, services, or some other form of value (e.g., money). There are several levels at which such interactions may be described, including:

Solution usage descriptions tend to focus on the interactions between a software solution user and the solution (product or service) being used.

Applicability

Use a usage description when

Considerations

Descriptions of business activities and software solution usage tend to focus on predicates and their transitive verbs (with active voice). Descriptions of solution usage may take several forms with lesser or greater levels of detail, including: feature descriptions, user stories, and use cases. For example, consider the business interactions between a loading bay clerk and a system for allocating storage space at a hazmat storage facility described as a use case, and depicted on the face card below.

Usage descriptions intend to answer the following questions:

Consequences

Usage descriptions often determine the overall structure (order) of the interactions between participants. Often these interaction sequences will imply a lifecycle whose states can be modeled and identified with descriptive adjectives.

depot accepts a delivered drum load
loading bay clerk wants to accept a delivered drum load
depot governors want to ensure depot safety compliance
loading bay must be empty
delivery truck has arrived at the loading bay
drum handler unloads drums from a truck into the loading bay
loading bay clerk selects drum load delivery
system accepts a delivery manifest for a drum load
loading bay clerk notifies the system after accepting each drum
system assigns drum ID and prints label for each drum
loading bay clerk notifies the system when the load is finished
system prints delivery reports
drum handler reloads any returned drums onto the truck

Figure 5. Drum Load Delivery