Robert C Kahlert, Developer in Korneuburg, Austria
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Robert C Kahlert

Verified Expert  in Engineering

Operating Systems Developer

Korneuburg, Austria
Toptal Member Since
September 4, 2020

Robert has taken on the architecture and documentation of great software—its engineering and research—for over 20 years. He loves designing and improving existing systems, creating content, and making systems and people collaborate in new ways. His focus areas include operating systems, compilers, databases, information modeling, and common sense reasoning. Robert has worked on research prototypes, development tools, and products in academia, at IBM, and for the symbolic AI platform, Cyc.


KU Leuven
Writing & Editing, Digital Humanities...
Cycorp, Inc.
Content Writing, Writing & Editing, ANTLR, Java, Apache ZooKeeper, RabbitMQ...
Cycorp, Inc.
Writing & Editing, C, ArcGIS, OpenMap, Apache POI, OWL, SAX, XSLT, DTD, XML...




Preferred Environment

Linux, IntelliJ IDEA

The most amazing...

...application we built at Cycorp used modus operandi reasoning to identify insurance fraud in prescription pain medication for a large mail-order pharmacy.

Work Experience

Research Toward (2nd) PhD

2018 - PRESENT
KU Leuven
  • Wrote materials for and taught a class on data modeling at the University of Luxemburg for the digital humanities master's degree program (
  • Conducted research on how to model historical art arguments using Davidsonian representation (
  • Researched how to model historical arguments using script-actor frameworks (
Technologies: Writing & Editing, Digital Humanities, Explainable Artificial Intelligence (XAI), Domain Research, University Teaching

Independent Consultant | Technical Architect

2013 - PRESENT
Cycorp, Inc.
  • Reduced on-disk encoding of a proprietary database format by 20%.
  • Fixed critical memory leaks in a low-level resourcing infrastructure.
  • Developed in-house tools for identifying allocation and execution hotspots.
  • Prototyped a parallel regression testing system using Redis, ZooKeeper, or RabbitMQ for task sharing and a parallel indexing system using the Akka Agents framework.
  • Made integrations with Llama and OpenAI for fine-tuning, including caching support to manage cost via Redis.
Technologies: Content Writing, Writing & Editing, ANTLR, Java, Apache ZooKeeper, RabbitMQ, JMH, ANTLR 4, Emacs Lisp, Franz Lisp, IntelliJ IDEA, RocksDB, Back-end, Artificial Intelligence (AI), Machine Learning

Senior Software Developer | System Architect

1998 - 2013
Cycorp, Inc.
  • Wrote the majority of the enterprise administration handbook for the common sense reasoning server, Cyc (
  • Authored a multi-part series on implementation details of core system components for faster onboarding of new hires using LaTeX.
  • Provided DevOps and system integration in AWS for an insurance fraud analysis tool for a large mail-order pharmacy client.
  • Ported the runtime of core technology from Linux/x86 to Win32, Win64, OS X, HP-UX Itanium, green and native threading, and, eventually, to Java.
  • Extended an in-house, 32-bit memory management system from 1GB to 3GB total object size.
  • Developed a declarative foreign-function call API with automatic marshaling between LISP and C programming languages.
  • Integrated an FOL theorem prover with spatial reasoning, using an OpenMap and ArcGIS system.
  • Assisted with introducing a CI/CD infrastructure, using Jenkins, and ported a core batch of build scripts to the CI/CD system.
  • Developed JDBC drivers for an FOL theorem prover and Microsoft spreadsheets (using POI).
  • Wrapped a FOL theorem prover with a JDBC driver to make proofs accessible in a SQL deployment context.
Technologies: Writing & Editing, C, ArcGIS, OpenMap, Apache POI, OWL, SAX, XSLT, DTD, XML, HTML, Jetty, Apache2, CVS, Subversion (SVN), Git, Groovy, Ruby, Python 2, Perl, JavaCC, Solaris, Windows API, Win32 API, Linux, Aleph, Alchemy, Weka, Pthreads, Itanium Assembler, SPARC Assembler, Assembler x86, C++, JavaScript, Java, Franz Lisp, Visual Studio, Eclipse IDE, NetBeans, Vim Text Editor, Emacs Lisp, Akka, Condor, MySQL, Apache Derby, PostgreSQL, JDBC, Zope, MediaWiki, Apache ZooKeeper, Hadoop, HDFS, Amazon Simple Queue Service (SQS), AWS SimpleDB, Amazon S3 (AWS S3), Amazon EC2, GNU Make, Ant Design, Apache Maven, Jira, Bugzilla, Back-end

University Assistant

1997 - 1998
University of Vienna
  • Developed a bibliographic database with search capabilities in Java and a browser-based front end.
  • Taught classes on basic computer and word processing use for incoming students.
  • Advised on the acquisition of computer equipment for the department and the school.
Technologies: Windows 95, PC, Java, Word Processing

Software Development Contractor

1989 - 1994
IBM Vienna System Development Lab
  • Implemented an automated build system with email notification for IBM AIX 1.0 Gold, using Make, CVS, C Shell (csh) scripts, and dedicated C programs. Wrote the maintenance document using Bookmaker.
  • Implemented a Videotex interpreter for OS/2, using C++ and Presentation Manager (IBM and Microsoft).
  • Built and implemented a telephone directory assistance prototype, using IBM AIX for a European national telecommunications company.
  • Developed sample applications, API demonstrations, and SDK documentation for the IBM ViaVoice dictation software for integration with OS/2.
  • Implemented a tracing and testing framework for debugging a legacy chart parser.
  • Provided IBM AIX memory and file services integration for REXX Compiler v3.
  • Implemented a drop-in replacement for a buggy malloc C library in the OS/2 tool suite.
Technologies: Writing & Editing, Bookmaker, Sendmail, Make, CVS, Videotex, WinNT, Assembly, RS/6000, REXX, CSH, C++, OS/2, AIX, Build Systems

System Administrator and Teaching Assistant

1986 - 1989
North Carolina State University
  • Provided setup, maintenance, and upgrade support for sixty workstations that were spread over three floors and running multiple operating systems.
  • Set up and supported high-performance graphics workstations.
  • Implemented backups and file system upgrades on the time-sharing system.
  • Taught labs for introductory programming (three semesters): developed examples, helped debug student code, and explained remaining issues after classroom instruction.
  • Served as a teaching assistant for the 400-level software engineering and software engineering project classes.
Technologies: University Teaching, Sage, Unix, Ultrix

File-less Java Heap Dump with Integrated Analyzer

The customer was running out of Java heap space, but the containers did not allow for the writing of Java heap dumps anywhere. I built a FUSE-based (filesystem in userspace) directory for the Java virtual machine (JVM) to write its heap, which did its heap analysis on the fly and kept only the summary statistics in memory.

Data Modeling for Digital Humanities Graduate Students
I developed a handout for the organized data modeling class at the University of Luxemburg, teaching data modeling, encoding, XML, Wikis, and SQL to students in the master's program for digital humanities. A detailed description (with pictures) is available here:

OpenCYC Common Sense Reasoning Project
I performed runtime infrastructure and knowledge store work as well as production support (unit testing and integration release tools) for this project from 2000 to 2018 when it was discontinued. I also shared responsibility for the OpenCYC Java API, especially those parts that dealt with knowledge store event handling and multi-threaded server communication. Finally, I wrote substantial portions of the administration guide for the knowledge server (

Academic Publications

Throughout my career, I have published multiple papers and one monograph ( on a variety of topics related to artificial intelligence, computer science, software engineering, and historical research (

AI-supported Content Analysis of PDF Proposals

A micromobility client wanted to know how their writing style influenced pitch acceptance. I used Python to convert their PDF submissions into text suitable for ML analysis. Google's VertexAI generated English parse trees and did sentiment analysis. I wrote a tree-walker for the parse trees to spot violations of the style guide. The initial prototype predicted successful pitch sentences well above chance.
2019 - 2021

Coursework Toward PhD (Ongoing) in Computer Science

Catholic University at Leuven - Leuven, Belgium

2013 - 2015

PhD in Religious Studies

University of Vienna - Vienna, Austria

1990 - 1997

Master's Degree in Religious Studies

University of Vienna - Vienna, Austria

1986 - 1989

Coursework Toward a Bachelor's Degree (Completed At University of Vienna) in Computer Science

North Carolina State University - Raleigh, NC, USA


JDBC, Win32 API, Sage, Pthreads, Windows API, SAX, Apache POI, ArcGIS


Make, Apache Maven, GNU Make, Apache ZooKeeper, JavaCC, Git, CVS, Sendmail, Bugzilla, Jira, Amazon Simple Queue Service (SQS), MediaWiki, Vim Text Editor, Eclipse IDE, Visual Studio, Weka, Subversion (SVN), Jetty, IntelliJ IDEA, ANTLR 4, RabbitMQ, ANTLR


Java, Assembly, Franz Lisp, Assembler x86, C++, CSH, REXX, Emacs Lisp, JavaScript, Perl, Python 2, Ruby, Groovy, HTML, XML, XSLT, OWL, C, SQL


Compiler Design, Parallel Programming, Continuous Integration (CI), Continuous Delivery (CD), REST


Ant Design, Hadoop, Zope, Akka, Alchemy, JMH


Unix, PC, Linux, AIX, WinNT, Amazon EC2, NetBeans, Solaris, Apache2, Vertex AI


PostgreSQL, Amazon S3 (AWS S3), AWS SimpleDB, HDFS, Apache Derby, MySQL, RocksDB, Databases, Database Modeling


Content Writing, Build Systems, Operating Systems, Software Engineering, OpenCYC, Design Documentation, Technical Architecture, Technical Writing, Technical Documentation, OS/2, RS/6000, Videotex, Bookmaker, Ultrix, Windows 95, Condor, SPARC Assembler, Itanium Assembler, Aleph, DTD, OpenMap, Artificial Intelligence (AI), Explainable Artificial Intelligence (XAI), Digital Humanities, University Teaching, API Documentation, Domain Research, Data Modeling, Builder, APIs, Open Source, Servers, Multithreading, Computer Science, Information Gathering, Expert Systems, Writing & Editing, Word Processing, Back-end, Machine Learning, Documentation

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