Event Calculus

The development of Event Calculus has spanned over both classical logic and logic programming traditions. The original version of the Event Calculus by Kowalski and Sergot (1986)KS86 was formulated as logic programs with negation as failure. More extensive later developments of the Event Calculus have been carried out under the classical logic setting via circumscription, e.g.

Web Ontology Language for description of Continuous Changes

Continuous changes are important piece of knowledge and common in sciences, robotics, and other domains which reason about mixed discrete-continuous systems. Descriptions of continuous changes, together with descriptions of objects and data, can be used for many forms of reasoning, e.g. simulation or prediction, planning, post-diction, and finding gaps in known information. Web ontology language for description of continuous changes or WOLCC is an ontology for the description of the quantitative aspects of continuous changes.KF12a

  • KF12a. Khandelwal, A., & Fox, P. (2012).

Combining FOL QR CLP DEs


There is no implementation for any form of reasoning (prediction, post-diction, planning, etc.) for Event Calculus with continuously varying parameters. We recently extended EC to specify independent component values of a cumulative effect individually which are summed implicitly. We want to implement a simulator that predicts evolution of a system of interacting processes for the extended EC formalism.

Event Calculus Additive Effects Independently

''Title'': Description of Cumulative Effects with Aggregates in the Event Calculus

''Authors'': [ ''Ankesh Khandelwal'']

''Note'': The main proposal here has been submitted to [ KR 2012] for peer-review.Here is a [ link] to the submitted version.


Extant works in AI that deal with continuous change.


An important component of Semantic Web is knowledge representation. Ontologies are used to describe the domain of data and then data is represented through ontologies. Thus data gets meaning. All types of things including persons, animals, universities, instruments, water activities, solar activities, and temperatures at sea, are represented on the Semantic Web. Most of these objects have properties that are real valued and they change continuously as function of properties and characteristics of itself and other influential objects.

PEO Working Groups

Process Ontologies

Description: Research and collecting of different process ontologies that could be used for the project
Members: Ankesh Khandelwal
Working Group Page

Combining Processes

Description: Combining First Order Logic, Qualitative Reasoning, ...
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Project Partners

Project Participants

Principal Investigator:

Peter Fox

Peter Fox is a Tetherless World Constellation Chair and Professor of Earth and Environmental Science, Computer Science and Cognitive Science at Rensselaer Polytechnic Institute. Fox also directs the Insitution-wide interdisciplinary Information Technology and Web Science program. Previously, he was [...]

Co Investigator:


Ankesh Khandelwal

Ankesh Khandelwal is a PhD candidate at RPI. During his training phase, first two year of PhD!, he worked towards formal analysis of the AIR language, a rule based policy language. After the training phase, he is looking into methods for representing complex knowledge, such as physical processes, [...]

Process Ontologies Summary Spring 2010


Our objective is to define a theory for processes of scientific nature and natural phenomena (SNP) and develop vocabulary around it for declarative specification of processes. To draw analogy, we want to do with processes what RDF, OWL(& OIL & DAML) and rules have done to domain knowledge representation. Before RDF, OWL & rules, data was tightly coupled with schema used for storage in a database, often relational and expensive to change, and the domain logic was mostly hard-coded in procedural programs, which made knowledge maintenance and integration difficult.

Process Ontologies


What is a Process?

  1. Process is a naturally occurring or designed sequence of changes of properties or attributes of an object or system. [Ref: Ref: Glossary of Systems Theory]
  2. Process model: An organized arrangement of systems concepts and principles that portray the behavior of a system through time.
  3. Process is a sequence of operations and involved events, taking up time, space, expertise or other resources, which lead to the production of some outcome.

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