In this paper, we describe, analyze and compare techniques for extracting spatial knowledge from a terrain model. Specifically, we investigate techniques for extracting a morphological representation from a terrain model based on an approximation of a Morse-Smale complex. A Morse-Smale complex defines a decomposition of a topographic surface into regions with vertices at the critical points and...

This paper discusses the optimal H∞ control synthesis via discrete Riccati equations for hard disk drives (HDDs) with an irregular sampling rate. A HDD servo system with an irregular sampling rate, caused by missing position error signal sampling data, is modeled as a linear periodically timevarying (LPTV) system. An optimal H∞ track-following control algorithm for HDD servo systems with irregu...

It has been known that the sparse approximate inverse preconditioning procedures SPAI and PSAI(tol) are costly to construct preconditioners for a large sparse nonsymmetric linear system with the coefficient matrix having at least one relatively dense column. This is also true for SPAI and the recently proposed sparse approximate inverse preconditioning procedure RSAI(tol) procedure when the mat...