Current Research Focus

In the years since I finished my doctoral research I have developed a keen interest in applying AI to problems in health and wellness. See my lab page for details of my current research projects.

Selected Publications

Past Projects

Integrating Reinforcement Learning into a Programming Language


I love to build software, I am interested means of expression both in natural and in artificial languages, and I am interested in intelligent systems. These three perspectives converged in my doctoral research: creating the building blocks to enable working programmers to build AI systems. In my doctoral research I integrated reinforcement learning into an experimental programming language and ran a programmer study to validate the usefulness of doing so. This language, AFABL (A Friendly Adaptive Behavior Langauge), is a domain-specific language embedded in Scala and includes abstractions for the direct expression of reinforcement learning problems. My programmer study suggested that integrating reinforcement learning into a programming language yields measurable software engineering benefits. I also invented an algorithm for composable modular reinforcement learning, Arbi-Q.

Possible future work: arbitration schemes for modular reinforcement learning that address limitations of Arbi-Q, abstraction mechanisms to support programming systems, unification of modular and hierarchical reinforcement learning.

Selected Publications

  • Christopher Simpkins and Charles L. Isbell. Composable Modular Reinforcement Learning. Proceedings of the 33rd National Conference on Artificial Intelligence (AAAI). Honolulu, HI. Febrary. 2019. PDF
  • Christopher Simpkins and Spencer Rugaber and Charles L. Isbell. DSL Design for Reinforcement Learning Agents. Workshop on Domain-Specific Language Design and Implementation. . October. 2017. PDF
  • Christopher Simpkins. Integrating Reinforcement Learning into a Programming Language. Proceedings of the 2010 SIGART/AAAI Doctoral Consortium. Atlanta, GA. July. 2010. PDF
  • Christopher Simpkins and Sooraj Bhat and Charles Isbell. Towards Adaptive Programming: Integrating Reinforcement Learning into a Programming Language. OOPSLA '08: ACM SIGPLAN Conference on Object-Oriented Programming, Systems, Languages, and Applications, Onward! Track. Nashville, TN USA. October. 2008. PDF
Mutual Information-Maximizing Input Clustering (MIMIC) for Antenna Design
Seth Markle, Denis Bueno, and I applied Charles Isbell's MIMIC algorithm to the design of planar array antennas. This work compared MIMIC to a previously published and very successful genetic algorithm approach employed by GTRI's Signature Technology Lab. We found MIMIC to be far superior in terms of execution time due to the computationally expensive evaluation function of real-world antennas. Software and publication in preparation.
Deriving Scientometric Information by Text Mining Scientific Publications
This work was in service of the research of Dr. Chiara Franzoni, an economist specializing in scientometrics. I applied text mining methods to a database of publication abstracts and biographical information for members of the American Physical Society. Our initial publication focused on finding patterns of specialization (in topic or research method) over time.

Selected Publications

  • Chiara Franzoni and Christopher Simpkins and Li Baoli and Ashwin Ram. Using Content Analysis to Investigate The Research Paths Chosen by Scientists Over Time. Scientometrics. . April. 2010. PDF
Using Optimization Algorithms to Design Neural Networks
This work was part of a larger project led by Dr. Paul Kemper in GTRI's Signature Technology Lab. The project sought effective machine learning algorithms for identifying RF emitters. In an effort to build on previously successful neural network approaches, Denis Bueno and I applied genetic and MIMIC optimization techniques to the design of neural network architectures.
MAT (MAT Analysis Tool): A GUI Analysis Platform for Materials Characterization Experiments
The MAT software package is a modular GUI platform for storing and alayzing materials experiments. I designed a data management system, a flexible user interface for displaying multiple experiments, and a modular plug-in architecture that enables the straightforward addition of new analysis modules, thereby leveraging the data storage and allowing analysts to easily compare experiment data in multiple ways in a single desktop application.
SACRE BLEU: Software-Assisted Content Review Based on Lanuage (English) Understanding
The SACRE BLEU project sought to develop software that identified information of interest in arbitrary human-language text, where information of interest is determined by both policy and precedent. The system is intended for application to the problem of content review for classified information where release officers must aprove the sharing of vast quantities of information on often very short deadlines. My role was to investigate user-adaptive methods and help manage the project, in particular the overall architecture and evaluation of technology components.
Casebook: An Adaptive Problem-Based Learning Environment
Casebook is Dr. Ashwin Ram's web-based platform for applying Problem-Based Learning in the classroom. By providing a suite of collaboration and research tools, and guiding students through the process of PBL, Casebook solves the primary obstacle to adoption of PBL in real-world classroms: the scalability of limited teacher-facilitator resources. Traditional PBL requires a great deal of involvement from the teacher to facilitate the process. Casebook takes care of a great deal of the details so that PBL can be effectively applied in real-world classrooms. I implemented software engineering practices, deployed and maintained the system for classroom research studies, and helped design Casebook 2, which is currently in development.