Note: Submission deadline extended to 3 May, 2013!

The biennial Workshop on Nonmonotonic Reasoning, Action and Change (NRAC) is an established workshop with an active and loyal community. Since its inception in 1995, it has always been held in conjunction with IJCAI, each time with growing success. We invite submissions of research papers for presentation at NRAC 2013, a one-day workshop to be held in Beijing, China as part of the International Joint Conference on Artificial Intelligence (IJCAI-13) workshop program.

An intelligent agent exploring a rich, dynamic world needs cognitive capabilities in addition to basic functionalities for perception and reaction. The abilities to reason nonmonotonically, to reason about actions and to change one's beliefs, have been identified as fundamental high-level cognitive functions necessary for common sense. Research in all three areas has made significant progress during the last two decades of the past century. It is, however, crucial to bear in mind the common goal of designing intelligent agents. Researchers should be aware of advances in all three fields since often advances in one field can be translated into advances in another. Many deep relationships have already been established. This workshop has the specific aim of promoting cross-fertilization. The interaction fostered by the biannual NRAC workshops has helped to facilitate solutions to the frame problem, ramification problem and other crucial issues on the research agenda.

Much recent research into reasoning about actions has been devoted to the design and implementation of languages and systems for Cognitive Robotics. Successful case studies demonstrate the applicability of these results for furnishing autonomous robots with high-level cognitive capabilities that enable plan-oriented behavior. Advancing the field of Cognitive Robotics, current research in reasoning about actions focuses on two crucial aspects of robots acting in open, real-world environments: Reasoning about knowledge and belief, and dealing with a challenge known as the qualification problem.

Autonomous, mobile robots choose most of their actions conditioned on the state of their environment. As their information about the world state is generally limited, robots are equipped with sensors for the purpose of acquiring information about the external world. The use of sensing actions is often an integral part of a successful plan, and in order to devise these plans robots need an explicit representation of what they believe the world looks like and how sensing affects their beliefs. Moreover, the execution of a plan needs to be constantly monitored and beliefs have to be revised in accordance with new observations. One goal of the workshop is to bring together researchers from the two areas of reasoning about actions and theory change, in order to join their effort of developing theories and designing systems for intelligent use of sensors and belief revision.

Intelligent agents acting in open environments inevitably face the qualification problem, that is, the executability of an action can never be predicted with absolute certainty; unexpected circumstances, albeit unlikely, may at any time prevent the agent from performing an intended action. Planning and acting under this proviso requires the agent to rigorously assume away, by default, all of the numerous possible but unlikely qualifications of their actions, lest the agent be unable to devise plans which, although not guaranteed of success, are perfectly reasonable. Assuming away unlikely but not impossible qualifications means that, if to the surprise of the agent an action actually fails, then the default conclusion should no longer be adhered to. In this respect the entire process is intrinsically nonmonotonic, which shows the increasing importance of pursuing the interrelation between reasoning about actions and nonmonotonic reasoning.

Comparing and contrasting our current formalisms for nonmonotonic reasoning, reasoning about action and belief revision helps identify the strengths and weaknesses of the various methods available. It is an important activity that allows researchers to evaluate the state-of-the-art. Indeed a significant advantage of using logical formalisms as representation schemes is that they facilitate the evaluation process. Moreover, following the initial success, more complex real-world applications are now within reach. An implementational testbed is a primary means by which existing theories of nonmonotonic reasoning, action and change are evaluated. Experimentation with prototype implementations not only helps to identify obstacles that arise in transforming theoretical solutions into operational solutions, but also highlights the need for the improvement of existing formal integrative frameworks for intelligent agents at the ontological level.

This workshop will bring together researchers from all three areas with the aim to:

Compare and evaluate existing formalisms.
Report on new developments.
Identify the most important open problems in all three areas.
Identify possibilities of solution transferral between the areas.
Identify important challenges for the advancement of the areas.

This workshop at IJCAI-2013 will provide a unique opportunity for researchers from all three fields to be brought together at a single forum with the prime objective to communicate important recent advances in each field and exchange ideas. As these fundamental areas mature it is vital that researchers maintain a dialogue through which they can cooperatively explore common links. The workshop's goal will be to work against the tendency of these rapidly advancing fields to drift apart.

* Special theme

This year's special theme is the qualification problem. That is, we especially encourage submissions that deal with any aspect of the fundamental problem of assuming away by default unexpected circumstances preventing the successful execution of an action. These aspects include, but are not limited to:

- New technical solutions for (aspects of) the qualification problem.
- Comparison of existing approaches to the qualification problem.
- The distinction between endogenous and exogenous qualifications, that is, those that can be explained within the theory vs. those that the theory can accommodate but not explain.
- The distinction between strong and weak qualifications, that is, circumstances that prevent an action from being executed altogether vs. circumstances that prevent an action from producing a desired effect.