TY - JOUR AB - We characterize critical points of 1-dimensional maps paired in persistent homology geometrically and this way get elementary proofs of theorems about the symmetry of persistence diagrams and the variation of such maps. In particular, we identify branching points and endpoints of networks as the sole source of asymmetry and relate the cycle basis in persistent homology with a version of the stable marriage problem. Our analysis provides the foundations of fast algorithms for maintaining collections of interrelated sorted lists together with their persistence diagrams. AU - Biswas, Ranita AU - Cultrera di Montesano, Sebastiano AU - Edelsbrunner, Herbert AU - Saghafian, Morteza ID - 11660 JF - LIPIcs TI - A window to the persistence of 1D maps. I: Geometric characterization of critical point pairs ER - TY - JOUR AB - The depth of a cell in an arrangement of n (non-vertical) great-spheres in Sd is the number of great-spheres that pass above the cell. We prove Euler-type relations, which imply extensions of the classic Dehn–Sommerville relations for convex polytopes to sublevel sets of the depth function, and we use the relations to extend the expressions for the number of faces of neighborly polytopes to the number of cells of levels in neighborly arrangements. AU - Biswas, Ranita AU - Cultrera di Montesano, Sebastiano AU - Edelsbrunner, Herbert AU - Saghafian, Morteza ID - 11658 JF - Leibniz International Proceedings on Mathematics TI - Depth in arrangements: Dehn–Sommerville–Euler relations with applications ER - TY - GEN AB - Given a locally finite set A⊆Rd and a coloring χ:A→{0,1,…,s}, we introduce the chromatic Delaunay mosaic of χ, which is a Delaunay mosaic in Rs+d that represents how points of different colors mingle. Our main results are bounds on the size of the chromatic Delaunay mosaic, in which we assume that d and s are constants. For example, if A is finite with n=#A, and the coloring is random, then the chromatic Delaunay mosaic has O(n⌈d/2⌉) cells in expectation. In contrast, for Delone sets and Poisson point processes in Rd, the expected number of cells within a closed ball is only a constant times the number of points in this ball. Furthermore, in R2 all colorings of a dense set of n points have chromatic Delaunay mosaics of size O(n). This encourages the use of chromatic Delaunay mosaics in applications. AU - Biswas, Ranita AU - Cultrera di Montesano, Sebastiano AU - Draganov, Ondrej AU - Edelsbrunner, Herbert AU - Saghafian, Morteza ID - 15090 T2 - arXiv TI - On the size of chromatic Delaunay mosaics ER - TY - JOUR AB - It is practical to collect a huge amount of movement data and environmental context information along with the health signals of individuals because there is the emergence of new generations of positioning and tracking technologies and rapid advancements of health sensors. The study of the relations between these datasets and their sequence similarity analysis is of interest to many applications such as health monitoring and recommender systems. However, entering all movement parameters and health signals can lead to the complexity of the problem and an increase in its computational load. In this situation, dimension reduction techniques can be used to avoid consideration of simultaneous dependent parameters in the process of similarity measurement of the trajectories. The present study provides a framework, named CaDRAW, to use spatial–temporal data and movement parameters along with independent context information in the process of measuring the similarity of trajectories. In this regard, the omission of dependent movement characteristic signals is conducted by using an unsupervised feature selection dimension reduction technique. To evaluate the effectiveness of the proposed framework, it was applied to a real contextualized movement and related health signal datasets of individuals. The results indicated the capability of the proposed framework in measuring the similarity and in decreasing the characteristic signals in such a way that the similarity results -before and after reduction of dependent characteristic signals- have small differences. The mean differences between the obtained results before and after reducing the dimension were 0.029 and 0.023 for the round path, respectively. AU - Goudarzi, Samira AU - Sharif, Mohammad AU - Karimipour, Farid ID - 10208 JF - Journal of Ambient Intelligence and Humanized Computing KW - general computer science SN - 1868-5137 TI - A context-aware dimension reduction framework for trajectory and health signal analyses VL - 13 ER - TY - JOUR AU - Adams, Henry AU - Kourimska, Hana AU - Heiss, Teresa AU - Percival, Sarah AU - Ziegelmeier, Lori ID - 10071 IS - 9 JF - Notices of the American Mathematical Society SN - 0002-9920 TI - How to tutorial-a-thon VL - 68 ER -