Stijn Heymans, PhD


From 2011 to 2014, I was a computer scientist at the Artificial Intelligence Center of SRI International working on Question Answering in the context of an intelligent Biology textbook, by means of Knowledge representation and reasoning techniques. In 2013, I co-founded Sheldonize, LCC where I developed in 2014 the web-based task manager

Further in the past, my work focused on Semantic Technologies. For more details check out my LinkedIn profile.


A simple open-source Datalog reasoner.[Python]
This is a web application that is a complete rewrite of todopl. It's a task manager that automatically schedules your to-dos on your calendar. It checks your existing meetings, and plans your work around them, while making sure deadlines for your tasks are met. I did all development. [Django (Python), Bootstrap]
ETB Datalog engine
The Evidential Tool Bus (ETB) is a distributed framework for tool integration for the purpose of building and maintaining assurance cases. ETB employs Datalog as a metalanguage both for defining workflows and representing arguments. I implemented the new core Datalog engine for the Evidential Tool Bus; more details on the theory of that engine can be found in the SAS 2014 paper. [Python]
This is a desktop application that instead of just maintaining lists of tasks also schedules these tasks on a schedule, taking into account meetings you have, deadlines, etc. I did all development. [Clojure, SWI-Prolog]
RAVE/Sunflower is an IDE for rule- and ontology editing. I wrote the tracer/debugger for RAVE/Sunflower, as well as several UI components in the Query module. [Flora-2, Java]
The Automated User-centered Reasoning and Acquisition System (AURA) allows subject matter experts, for example, biologists, physicists, and chemists, and scientific educators to formulate knowledge and questions to query that knowledge. I contributed to and maintained large chunks of code in the Question Answering module of AURA. [Common Lisp]
This was a prototype that slurped in FDA Adverse Event data as well as your Google Health profile and determined whether you where currently at risk of any drug interactions based on your medications. [SWI-Prolog]
A Reasoner for Simple Conceptual Programs under the Open Answer Set Semantics. The theory behind this reasoner has been written down in a RR 2009 paper. [B-Prolog]


FOIS 2014 Conceptual Models of Energy Transfer and Regulation
AAAI 2014 Large-Scale Analogical Reasoning
SAS 2014 The Semantics of Datalog for the Evidential Tool Bus (Extended Abstract)
GKRIJCAI 2013 Automatic Strengthening of Graph-Structured Knowledge Bases
ORE 2013 KB_Bio_101: A Challenge for OWL Reasoners
KInAR 2013 KB_Bio_101: A Challenge for TPTP First-Order Reasoners
TC ICLP 2013 Object-Oriented Knowledge Bases in Logic Programming
ASPOCP 2013 Query Answering in Object Oriented Knowledge Bases in Logic Programming: Description and Challenge for ASP
AAMAS 2013 “What If There Was No Oxygen?”: Responding to Hypothetical Questions in an Intelligent Tutoring Agent (Extended Abstract)
E-LKR 2012 KB_Bio_101: A Repository of Graph-Structured Knowledge
DKRC 2012 Process Interruption Reasoning
SWWS 2012 The DReW System for Nonmonotonic DL-Programs
TPLP 2011 Reasoning with Forest Logic Programs and f-hybrid Knowledge Bases
Bio Sem 2011 Semantic Validation of the Use of SNOMED CT in HL7 Clinical Documents
USDL 2011 Semantic Web Services Fundamentals
JAIR 2010 Logical Foundations of RDF(S) with Datatypes
ASPOCP 2010 An Optimization for Reasoning with Forest Logic Programs
WI 2010 F-Logic#: Loosely Coupling F-Logic Rules and Ontologies
ECAI 2010 Tractable Reasoning with DL-Programs over Datalog-rewritable Description Logics
ESWC 2010 Dealing with Inconsistency when Combining Ontologies and Rules using DL-Programs
BuRO 2010 DReW: a Reasoner for Datalog-rewritable Description Logics and DL-Programs
LPNMR 2009 Complexity of the Stable Model Semantics for Queries on Incomplete Databases
ESWC 2009 Hybrid Reasoning with Forest Logic Programs
RR 2009 A Reasoner for Simple Conceptual Logic Programs
LFCS 2009 Fuzzy Description Logic Reasoning using a Fixpoint Algorithm
FI 2008 On the Relationship between Description Logic-based and F-Logic-based Ontologies
ALPSWS 2008 A Sound and Complete Algorithm for Simple Conceptual Logic Programs
TPLP 2008 Guarded Hybrid Knowledge Bases
Onto Mag 2008 Ontology Reasoning with Large Data Repositories
ACM TOCL 2007 Open Answer Set Programming with Guarded Programs
RR 2008 Ranking Services Using Fuzzy HEX Programs
ICLP 2008 Compiling Fuzzy Answer Set Programs to Fuzzy Propositional Theories
JAIT 2008 Towards Pattern-Based Reasoning for Friendly Ontology Debugging
URSW 2008 Deciding Fuzzy Description Logics by Type Elimination
DL 2008 The SAT-Tableau Calculus
ISWC/ASWC2007 Logical Foundations of (e)RDF(S): Complexity and Reasoning
RR 2007 A Semantic Framework for Language Layering in WSML
WEBS 2007 RDF and Logic: Reasoning and Extension
JAL 2007 Open Answer Set Programming for the Semantic Web
WEBIST 2007 Spinning a corporate Semantic Web for Product Engineering
SBPM 2007 Semantic Business Process Repository
ESWC 2007 Two-Phase Web Service Discovery Based on Rich Functional Descriptions
WIMBI 2006 A Semantically Enabled Service Oriented Architecture
RuleML 2006 Translating Ontologies from Predicate-based to Frame-based Languages
AMAI 2006 Conceptual Logic Programs
PhD Thesis 2006 Decidable Open Answer Set Programming
ALPSWS 2006 G-hybrid Knowledge Bases
FoIKS 2006 Guarded Open Answer Set Programming with Generalized Literals
RoW 2006 Reasoning with the Description Logic DLRO-lessthan using Bound Guarded Programs
EDBT 2006 Unsatisfiability Reasoning in ORM Conceptual Schemes
ECAI 2006 Approximating Extended Answer Sets
ICLP 2006 Cooperating Answer Set Programming
CLIMA-VII 2006 Hierarchical Decision Making in Multi-agent Systems Using Answer Set Programming
LPNMR 2005 Guarded Open Answer Set Programming
ESWC 2005 Nonmonotonic Ontological and Rule-Based Reasoning with Extended Conceptual Logic Programs
ISWC 2005 Preferential Reasoning on a Web of Trust
ICTCS 2005 Synthesis from Temporal Specifications Using Preferred Answer Set Programming
PADLD 2005 An Ordered Logic Program Solver
JELLIA 2004 Hierarchical Decision Making by Autonomous Agents
RuleML 2004 Semantic Web Reasoning with Conceptual Logic Programs
ICLP 2004 On Programs with Linearly Ordered Multiple Preferences
LPAR 2004 Weighted Answer Sets and Applications in Intelligence Analysis
PPSWR 2003 Integrating Description Logics and Answer Set Programming
WEBS 2003 Integrating Ontology Languages and Answer Set Programming
ASP 2003 Integrating Semantic Web Reasoning and Answer Set Programming
ODBASE 2002 A Defeasible Ontology Language
WEBS 2002 Using Preference Order in Ontologies

You can find bibliographic details for all of these at Bibsonomy.