representative point
86b8ad667206fb9a52ae575fbf1cd6be-Paper-Conference.pdf
In this paper, we study the fundamental problems of maintaining the diameter and a k-center clustering of a dynamic point set P Rd, where points may be inserted or deleted over time and the ambient dimension dis not constant and may be high. Our focus is on designing algorithms that remain effective even in the presence of an adaptive adversary--an adversary that, at any time t, knows the entire history of the algorithm's outputs as well as all the random bits used by the algorithm up to that point. We present a fully dynamic algorithm that maintains a 2-approximate diameter with a worst-case update time of poly(d,logn), where n is the length of the stream. Our result is achieved by identifying a robust representative of the dataset that requires infrequent updates, combined with a careful deamortization. To the best of our knowledge, this is the first efficient fully-dynamic algorithm for diameter in high dimensions that simultaneously achieves a 2-approximation guarantee and robustness against an adaptive adversary. We also give an improved dynamic (4+ฯต)-approximation algorithm for the k-center problem, also resilient to an adaptive adversary.
Efficient Computation of a Continuous Topological Model of the Configuration Space of Tethered Mobile Robots
Battocletti, Gianpietro, Boskos, Dimitris, De Schutter, Bart
Despite the attention that the problem of path planning for tethered robots has garnered in the past few decades, the approaches proposed to solve it typically rely on a discrete representation of the configuration space and do not exploit a model that can simultaneously capture the topological information of the tether and the continuous location of the robot. In this work, we explicitly build a topological model of the configuration space of a tethered robot starting from a polygonal representation of the workspace where the robot moves. To do so, we first establish a link between the configuration space of the tethered robot and the universal covering space of the workspace, and then we exploit this link to develop an algorithm to compute a simplicial complex model of the configuration space. We show how this approach improves the performances of existing algorithms that build other types of representations of the configuration space. The proposed model can be computed in a fraction of the time required to build traditional homotopy-augmented graphs, and is continuous, allowing to solve the path planning task for tethered robots using a broad set of path planning algorithms.
while A.3 is a common assumption in linear regression analysis and it relates to the LARS problem in our online
We thank all the reviewers for carefully reading of the manuscript and constructive comments. Reviewer #1: Assumptions A.2 and A.3 used in Algorithm 2. Reviewer #3: There seem to be several misunderstandings regarding the steps of our algorithm and its analysis. To maintain the list constant, for every added point another point is removed.