## Chze Eng Seah

### Research

My research interest is in hybrid system modeling, hybrid estimation algorithms and applications.

A hybrid system contains interacting continuous state and discrete state. The continuous state dynamics is usually described by a set of differential equations (or difference equations). In many stochastic hybrid system models, the discrete state evolution (or mode transition) is assumed to be a Markov process with a constant mode transition probability independent of the continuous state evolution. However, in many hybrid systems, the mode transitions may be induced by the evolution of the continuous state. An example is an aircraft subsystem that changes from an `operational' state to a `faulty' state when its temperature goes beyond a critical value Tc. I am interested in modeling of stochastic hybrid systems that have discrete state transitions (or mode transitions) that depend explicitly on the continuous state.

I have investigated algorithms to solve the hybrid estimation problem for stochastic linear hybrid system (SLHS) with continuous-state-dependent mode transitions. Based on the well-known Interacting Multiple Model algorithm, I have developed a hybrid estimation, called the SDTHE algorithm, for theÂ SLHS. This hybrid estimation have been used in aircraft tracking application in Air Traffic Control.

I am interested in other possible applications in the areas such as fault diagnosis, aircraft trajectory prediction and intent inference. I have proposed an algorithm to carry out aircraft conformance monitoring in Air Traffic Control based on a fault detection concept using the SLHS model and the SDTHE algorithm. Further applications in fault detection and isolation are currently being investigated.

### Publications

C.-E. Seah and I. Hwang, "Hybrid Estimation Algorithm using State-Dependent Mode Transition Matrix for Aircraft Tracking," *In the Proceedings of the **AIAA Guidance, Navigation, and Control Conference, Keystone, CO, August 2006.*

I. Hwang and C.E. Seah. An estimation algorithm for stochastic linear hybrid systems with continuous-state-dependent mode transitions. In Proceedings of the 45th IEEE Conference on Decision and Control, pp. 131-136, San Deigo, CA, USA, December 2006.

C.E. Seah and I. Hwang. Target tracking of arrival aircraft using hybrid estimation. In 44th Annual Allerton Conference on Communication, Control, and Computing, Monticello, IL, September 2006.

C.E. Seah and I. Hwang. Hybrid estimation for stochastic piecewise linear systems. In Hybrid Systems: Computation and Control, Lecture Notes in Computer Science, Springer-Verlag, 2007.

C.-E. Seah and I. Hwang, "A Hybrid Estimation Algoithm for Terminal Aircraft Tracking," *In the Proceedings of** **the AIAA Guidance, Navigation, and Control Conference**, Hilton Head, SC, August **2007.*

C.-E. Seah and I. Hwang, "Stability Analysis of the Interacting Multiple Model Algorithm," *In the Proceedings of ** the AACC American Control Conference, Seattle, WA, June **2008.*

C.-E. Seah and I. Hwang, "Performance Analysis of Kalman Filter Based Hybrid Estimation Algorithms," *In the Proceedings of** the IFAC World Congress, **Seoul, Korea, July 2008.*

C.-E. Seah and I. Hwang*, "Terminal-Area Aircraft Tracking by Hybrid Estimation," AIAA Journal of Guidance, Control and Dynamics, (submitted on July 29, 2008; accepted on November 20, 2008)*

I. Hwang and C.-E. Seah*, "**Intent Based Probabilistic Conflict Detection for the Next Generation Air Transportation System," Proceedings of the IEEE Special Issue on Aviation Information Systems, Vol. 96 (12), December 2008.*

C.-E. Seah and I. Hwang*, "Stochastic Linear Hybrid Systems: Model and Estimation and Application to Air Traffic Control," IEEE Transactions on Control Systems Technology, (submitted in March 2007, accepted in May 2008).*

C.-E. Seah and I. Hwang*, "State Estimation for Stochastic Linear Hybrid Systems: An IMM Approach," IEEE Transactions on Aerospace and Electronic Systems, Vol. 45(1), January 2009. (submitted on March 13, 2007, accepted in January 24, 2008).*

I. Hwang, S. Kim, Y. Kim, and C.-E. Seah, "A Survey of Fault Detection, Identification, and Reconfiguration Methods", *IEEE Transactions on Control Systems Technology, (submitted in January 5, 2009, under review)*

C.-E. Seah and I. Hwang*, "Algorithm for Performance Analysis of Kalman Filter Based Hybrid Estimation," IEEE Transactions on Aerospace and Electronic Systems, (submitted on August 13, 2008; conditionally accepted on January 11, 2009)*

J. Li, C.-E. Seah, and I. Hwang, "A Spectral Clustering Based Algorithm for Dynamic Airspace Configuration," *In the Proceedings of the AIAA Aviation Technology, Information, and Operations Conference, Hillton Head, SC, September 2009, submitted*

J. Li, C.-E. Seah, and I. Hwang, "An Algorithm for Dynamic Airspace Configuration based on the Air Route Structure," *In the Proceedings of the AIAA Guidance, Navigation, and Control Conference, Chicago, IL, August 2009, submitted.*

C.-E Seah, A. Aligawesa, and I. Hwang, "An Algorithm for Conformance Monitoring in Air Traffic Control," *In the Proceedings of the AIAA Guidance, Navigation, and Control Conference, Chicago, IL, August 2009, submitted.*

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