Object Action Complex
Encyclopedia
Object-Action Complexes (OACs) are proposed as a universal representation enabling efficient planning and execution of purposeful action at all levels of a cognitive architecture
(Kruger 2009, Worgotter 2008, Geib 2006, Piater 2009). OACs combine the representational and computational efficiency
for purposes of search (the frame problem) of STRIPS
rules and the object- and situation-oriented concept of affordance
with the logical clarity of the event calculus
. Affordance is the relation between a situation, usually including an object of a defined type, and the actions that it allows. While affordances have mostly been analyzed in their purely perceptual aspect, the OAC concept defines them more generally as state transition functions suited to prediction. Such functions can be used for efficient forward chaining
planning, learning, and execution of actions represented simultaneously at multiple levels in an embodied agent architecture.
The PACO+ project, an Integrated Project funded by the European Commission
through its Cognition Unit under the Information Society Technologies of the sixth Framework Programme
(FP6), and launched on 1 February 2006, brings together an interdisciplinary research team to design and build cognitive robots
capable of developing perceptual, behavioural and cognitive categories that can be used, communicated and shared with other humans and artificial agents. In the project they hypothesize that such understanding can only be attained by embodied agents and requires the simultaneous consideration of perception and action resting on three foundational assumptions:
Cognitive architecture
A cognitive architecture is a blueprint for intelligent agents. It proposes computational processes that act like certain cognitive systems, most often, like a person, or acts intelligent under some definition. Cognitive architectures form a subset of general agent architectures...
(Kruger 2009, Worgotter 2008, Geib 2006, Piater 2009). OACs combine the representational and computational efficiency
Efficiency
Efficiency in general describes the extent to which time or effort is well used for the intended task or purpose. It is often used with the specific purpose of relaying the capability of a specific application of effort to produce a specific outcome effectively with a minimum amount or quantity of...
for purposes of search (the frame problem) of STRIPS
STRIPS
In artificial intelligence, STRIPS is an automated planner developed by Richard Fikes and Nils Nilsson in 1971. The same name was later used to refer to the formal language of the inputs to this planner...
rules and the object- and situation-oriented concept of affordance
Affordance
An affordance is a quality of an object, or an environment, which allows an individual to perform an action. For example, a knob affords twisting, and perhaps pushing, while a cord affords pulling...
with the logical clarity of the event calculus
Event calculus
The event calculus is a logical language for representing and reasoning about actions and their effects first presented by Robert Kowalski and Marek Sergot in 1986.It was extended by Murray Shanahan and Rob Miller in the 1990s....
. Affordance is the relation between a situation, usually including an object of a defined type, and the actions that it allows. While affordances have mostly been analyzed in their purely perceptual aspect, the OAC concept defines them more generally as state transition functions suited to prediction. Such functions can be used for efficient forward chaining
Forward chaining
Forward chaining is one of the two main methods of reasoning when using inference rules and can be described logically as repeated application of modus ponens. Forward chaining is a popular implementation strategy for expert systems, business and production rule systems...
planning, learning, and execution of actions represented simultaneously at multiple levels in an embodied agent architecture.
The PACO+ project, an Integrated Project funded by the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
through its Cognition Unit under the Information Society Technologies of the sixth Framework Programme
Framework Programmes for Research and Technological Development
The Framework Programmes for Research and Technological Development, also called Framework Programmes or abbreviated FP1 through FP8, are funding programmes created by the European Union in order to support and encourage research in the European Research Area...
(FP6), and launched on 1 February 2006, brings together an interdisciplinary research team to design and build cognitive robots
Cognitive robotics
a robot is a robot device that is built from inanimate matter. Its behavior in response to the environment is deterministic, based on how the robot was designed. Cognition is the process of acquiring and using knowledge about the world for goal-oriented purposes, such as survival...
capable of developing perceptual, behavioural and cognitive categories that can be used, communicated and shared with other humans and artificial agents. In the project they hypothesize that such understanding can only be attained by embodied agents and requires the simultaneous consideration of perception and action resting on three foundational assumptions:
- Objects and Actions are inseparably intertwined in cognitive processing; that is “Object-Action Complexes” (OACs) are the building blocks of cognitionCognitionIn science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...
.
- Cognition is based on reflective learning, contextualizingContextualizationContextualization may refer to:* Contextualization , the process of contextualising the biblical message as perceived in the missionary mandate originated by Jesus...
and then reinterpreting OACs to learn more abstract OACs, through a grounded sensing and action cycle.
- The core measure of effectivenessEffectivenessEffectiveness is the capability of producing a desired result. When something is deemed effective, it means it has an intended or expected outcome, or produces a deep, vivid impression.-Etymology:...
for all learned cognitive structures is: Do they increase situation reproducibility and/or reduce situational uncertainty in ways that allow the agent to achieve its goals?
Further reading
- Krüger, N., Piater, J., Wörgötter,F., Geib, Ch., Petrick, R., Steedman, M.; Ude, A., Asfour, T., Kraft, D., Omrcen, D., Hommel, B., Agostino, A., Kragic, D., Eklundh, J., Kruger, V. and Dillmann, R.(2009). A Formal Definition of Object Action Complexes and Examples at different Levels of the Process Hierarchy.
- Wörgötter, F., Agostini, A., Krüger, N., Shylo, N. and Porr, B. Cognitive agents - a procedural perspective relying on the predictability of Object-Action-Complexes (OACs). Robotics and Autonomous Systems, 2008.
- Geib, Ch., Mourao, K., Petrick, R., Pugeault, N., Steedman, M., Krüger, N. and Wörgötter, F. Object Action Complexes as an Interface for Planning and Robot Control. IEEE-RAS International Conference on Humanoid Robots (Humanoids 2006).
- Justus Piater, Mark Steedman, Florentin Wörgötter. Learning in PACO-PLUS.