Lijian Chen (陈力简)

Home of novel methods for stochastic programming

 

This picture was taken at the 12th International Conference on Stochastic Programming at Halifax, Nova Scotia.

 

5241 Craigs Creek Dr.

Louisville, KY 40241

Spam free email: lijian.chen@outlook.com

Office: 502-852-2197

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Cell: 502-298-4672

I am interested in developing novel, largely computational methods, to solve the large scale stochastic programming. These novel methods become increasingly implementable because of two facts: first, the exponential growth rates of computational capabilities in the last three decades described by the Moores law; second, all of my novel methods have polynomial computational complexities.

 

Our contribution is to incorporate the recently emerged, efficient optimization techniques to the field of stochastic programming. The state-of-the-art research of stochastic programming is largely about the statistical properties of the approximation, such as the convergence with probability one or the large deviation theory. Despite a few impressive applications, the numerical performances of difficult problems, e.g., the chance constrained optimization, the large-scale two stage recourse problem, and the multi-stage stochastic programming, are still up in the air. It is fair to say that the currently solver can only solve low-dimensional, highly simplified problems. On the other hand, the optimization techniques in general, have been fast improved in the past two decades, thanks to the development and implementation of the interior-point methods. The marriage between stochastic programming and efficient optimization techniques, has not yet, but surely will be established. I sincerely hope that my novel methods will play an important role for this exciting liaison.

 

All my novel methods decompose the large scale stochastic programming into many but a manageable number of auxiliary convex problems without compromising the solution quality. The implementation of our methods will endorse a distributed computational infrastructure which will lead to considerable savings and timely solutions. Our methods have been used in the following applied research topics toward gaining scientific knowledge to meet a recognized need: 

 

* Engineering: Chance constrained Air traffic flow (ATF) optimization under stochastic capacity for the Next Generation Air Transportation System (NextGen)

* Business: Chance constrained supply chain management for the artificial cancer drug shortage

* Health-care: Chance constrained proton treatment plan optimization

* Business: Stochastic control-based public-private partnership for the civil infrastructures

* Business: Stochastic control-based dynamic pricing and revenue management

 

Conducting research to develop novel methods for efficient, reliable, and robust solvers for difficult problem is always a lofty goal of dedicated ORMS researchers. However, the commitment on this lofty goal by a junior faculty means a difficult time prior to the recognitions from peers. So far, the following basic research topics, toward gaining scientific knowledge on stochastic programming for its own sake, have been completed:

* Preprocessing Monte-Carlo sample for efficient solution of the large-scale stochastic programming, (pdf), (numerical codes)

* Solving large scale chance constrained optimization by approximations for logarithmic concave and continuous distributions, (pdf), (numerical codes)

Please refer to here for manuscripts and numerical codes. The following basic research topics are under active investigation.

* Preprocessing Monte-Carlo sample for Stochastic Control and Multi-Stage Stochastic Programming

* Solving large scale chance constrained optimization by approximations for qualified discrete distributions.

Conducting research is a mix of fun and pain. A good analogy is to hike through the tunnel. Only dedicated individuals would see the light from another end. For my case, I am seeing the light and I am sure the light at the end of the tunnel is not a train. Mounting supports from my beloved wife, collaborators, peers, friends, interested parties, and Federal agencies are coming in favor of my team.

-      Lijian Chen

 

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