A curvature-based algorithm to simplify a polygonal curve is described, together with its implementation. The so-called SimpliPoly algorithm uses Bézier curves to approximate pieces of the input curve, and assign curvature estimates to vertices of the input polyline from curvature values computed for the Bézier approximations. The authors' implementation of SimpliPoly is interactive and available freely on-line. Additionally, a third-party implementation of SimpliPoly as a plug-in for the GNU Blender 3D modeling software is available. Empirical comparisons indicate that SimpliPoly performs as well as the widely-used Douglas-Peucker algorithm in most situations, and significantly better, because it is curvature-driven, in applications where it is necessary to preserve local features.

The mobility-enabling protocol Mobile IP supports location registration but not paging. However, current cellular networks use registration as well as paging procedures to minimize signaling cost. Accordingly, an extension to Mobile IP using distributed individual paging, the so-called DIP-MIP, is proposed. In DIP-MIP, each mobile host derives its own paging area size by optimizing a signaling cost function based on its individual mobility pattern. The cost function itself may use either of two mobility models -fluid flow and random walk -and the performance of DIP-MIP is analyzed for both. The impact of various parameters on the DIP-MIP signaling cost is studied as well. The performance of DIP-MIP is shown to be superior to that of Mobile IP (MIP) in reducing signaling load, managing mobility and supporting a large number of mobile users in IP-based cellular networks.

A user's profile, for the purpose of location management in a personal communication service (PCS) network, is formalized as a subgraph of the network graph. This subgraph, the so-called individual profile graph (IPG), is determined after a period of observation with the intent of predicting and codifying the user's diurnal routine. The IPG is easily-motivated, robust, straightforwardly computed from observed data, and, under fairly intuitive assumptions, provably predictive of the user's diurnal routine. An IPG-based paging and update strategy is analyzed. It is shown to significantly improve a straight location area (LA) based strategy that ignores user profiles.

Abstract-We present a novel algorithm to segment a 3D surface mesh into visually meaningful regions. Our approach is based on an analysis of the local geometry of vertices. In particular, we begin with a novel characterization of vertices as convex, concave or hyperbolic based upon their discrete local geometry. Hyperbolic and concave vertices are considered potential feature region boundaries. We propose a new region growing technique starting from these boundary vertices leading to a segmentation of the surface that is subsequently simplified by a region-merging method. Experiments indicate that our algorithm segments a broad range of 3D models at a quality comparable to existing algorithms. Its use of methods that belong naturally to discretized surfaces and ease of implementation make it an appealing alternative in various applications.

Abstract-We develop a polygonal mesh simplification algorithm using a vertex-decimation approach. The novelty in our method lies in (a) a characterization of mesh vertices as hyperbolic or non-hyperbolic based upon their discrete local geometry, (b) the cost function used to select a vertex for decimation, and (c) the heuristics applied to re-triangulate the resulting hole. The algorithm begins by classifying the input mesh vertices as hyperbolic or non-hyperbolic, and then computes a volume cost for each non-hyperbolic vertex, in analogy with spherical volume, to capture the loss of fidelity if that vertex is decimated. Vertices of least volume cost are successively deleted and the resulting hole re-triangulated. Preliminary experiments indicate a performance comparable to that of the best known mesh simplification algorithms.