The Object-Action (or visa-versa) model and its applications

From Computing and Software Wiki

Contents 1 Background 1.1 Object Action Interface 1.2 Action Object Interface 2 Scope 3 Principles 3.1 OAI Model 3.2 Syntactic Knowledge 4 Task hierarchies of objects and actions 4.1 User 4.2 Designer 5 Interface hierarchies of objects and actions 5.1 Interface Objects 5.2 Interface Actions 5.3 User 5.4 Designer 6 Limitations and Challenges 7 References

Background

Object Action Interface or Action Object Interface is changing the way people interact with systems. As more and more systems switch from text mode command based languages to Graphical User Interface (GUI) the problem now lies with visually representing and displaying of user's tasks objects and actions. Before GUI was implemented in systems and users had to remember a set of commands and if they ever had to use a command which was not used frequently they would have to refer to another user of the manual pages.

Object Action Interface is basically an extension to the Graphical User Interface, it also relates to Direct Manipulation User Interface. DMUI can help create better Human Computer Interfaces and can also increase the usability of the product

There are two basic interaction models for any given system.

Object Action Interface

In this model the user will select the object first and then select the action which will be performed on the object.

Example: In Windows, if you want to copy a file you will first select a file (Object) and then right click and select copy (Action).

Action Object Interface

In this model the user will select an action and then select the object the action will be performed on.

Example: In command prompt, if you want to copy a file you will input copy <Source File> <Destination File>. 'Copy' which is the action comes before the object '<Source File>'

Scope

Principles

OAI Model

Syntactic Knowledge

Task hierarchies of objects and actions

Tasks are composed of objects and actions at high and low levels. Not all users will find these hierarchies to be perfect, but since they are comprehensible, a great deal of usefulness is provided.

User

Dividing complex tasks into sub-tasks and solving the sub-tasks independently has been shown to be a successful way to solve larger complex problems. Most real world objects and entities involve the use of this property of creating sub-tasks create a plan of smaller action steps. People learn tasks actions and objects within their lifetime and realize that the process is simplified greatly, when managing different smaller levels within a hierarchy. Issues of implementation are not considered as much when executing tasks using this method.

Designer

Three steps are suggested by Ben Shneiderman, the creator of the 8 golden rules for interface design, for designers to correctly build a task hierarchy.

   1. Know about the users and their tasks (Interviewing users, reading workbooks and taking training sessions)
   2. Generate hierarchies of tasks and objects to model the users' tasks
   3. Design interface objects and actions that metaphorically map to the real world universe

Interface hierarchies of objects and actions

Interface Objects

Interface Actions

User

Designer

Limitations and Challenges

Each user's way of performing a task may vary. Defining steps completely with metaphors creates risk in the varying interpretations of metaphors amongst different users. Designers of object-action models must consider the wide range of interpretations that are possible when deciding on metaphors for an object.

References

• Amir Khella, Object Action Interface Model