7,291 research outputs found
Replication Data for: Slant, Extremity, and Diversity - How the Shape of News Use Explains Electoral Judgments and Confidence
No full textThis dataset contains the replication data for "Slant, Extremity, and Diversity: How the Shape of News Use Explains Electoral Judgments and Confidence
Research on graphene/silicon Schottky junction based photodetector
Get PDFL'abstract è presente nell'allegato / the abstract is in the attachmen
Prioritized target tracking with active collaborative cameras
No full textMobile cameras on robotic platforms can support fixed multi-camera installations to improve coverage and target localization accuracy. We propose a novel collaborative framework for prioritized target tracking that complement static cameras with mobile cameras, which track targets on demand. Upon receiving a request from static cameras, a mobile camera selects (or switches to) a target to track using a local selection criterion that accounts for target priority, view quality and energy consumption. Mobile cameras use a receding horizon scheme to minimize tracking uncertainty as well as energy consumption when planning their path. We validate the proposed framework in simulated realistic scenarios and show that it improves tracking accuracy and target observation time with reduced energy consumption compared to a framework with only static cameras and compared to a state-of-the-art motion strategy
Concurrent Target Following with Active Directional Sensors
No full textWe propose a collision-avoidance tracker for agents with a directional sensor that aim to maintain a moving target in their field of view. The proposed tracker addresses the view maintenance issue within an Optimal Reciprocal Collision Avoidance (ORCA) framework. Our tracking agents adaptively share the responsibility of avoiding each other and minimise with a smooth actuation the deviation angle from their heading direction to their target. Experimental results with real people trajectories from public datasets show that the proposed method improves view maintenance
Coalition formation for distributed tracking in wireless camera networks
No full textWe present a fully distributed framework for multi-target tracking with bandwidth-limited (wireless) camera networks. Cameras self-organize into coalitions to perform the task of distributed target tracking via local interactions. Each camera joins the coalitions based on considerations of marginal utility, which takes into account tracking confidence and communication performance in the neighborhood of the camera. The proposed framework achieves higher tracking accuracy and quicker convergence than decentralized tracking or distributed tracking without coalition formation. Moreover, the communication cost of the proposed framework is considerably reduced compared to distributed tracking without coalition formation and comparable to decentralized tracking as the number of targets increases
Active visual tracking in multi-agent scenarios
No full textWe propose an active visual tracker with collision avoidance for camera-equipped robots in dense multi-agent scenarios. The objective of each tracking agent (robot) is to maintain visual fixation on its moving target while updating its velocity to avoid other agents. However, when multiple robots are present or targets intensively intersect each other, robots may have no accessible collision-avoiding paths. We address this problem with an adaptive mechanism that sets the pair-wise responsibilities to increase the total accessible collision-avoiding controls. The final collision-avoiding control accounts for motion smoothness and view performance, i.e. maintaining the target centered in the field of view and at a certain size. We validate the proposed approach under different target-intersecting scenarios and compare it with the Optimal Reciprocal Collision Avoidance and the Reciprocal Velocity Obstacle methods
Improved Algorithms for Distance Selection and Related Problems
Get PDFIn this paper, we propose new techniques for solving geometric optimization problems involving interpoint distances of a point set in the plane. Given a set P of n points in the plane and an integer 1 ≤ k ≤ binom(n,2), the distance selection problem is to find the k-th smallest interpoint distance among all pairs of points of P. The previously best deterministic algorithm solves the problem in O(n^{4/3} log² n) time [Katz and Sharir, 1997]. In this paper, we improve their algorithm to O(n^{4/3} log n) time. Using similar techniques, we also give improved algorithms on both the two-sided and the one-sided discrete Fréchet distance with shortcuts problem for two point sets in the plane. For the two-sided problem (resp., one-sided problem), we improve the previous work [Avraham, Filtser, Kaplan, Katz, and Sharir, 2015] by a factor of roughly log²(m+n) (resp., (m+n)^ε), where m and n are the sizes of the two input point sets, respectively. Other problems whose solutions can be improved by our techniques include the reverse shortest path problems for unit-disk graphs. Our techniques are quite general and we believe they will find many other applications in future
Dynamic Unit-Disk Range Reporting
Get PDFFor a set P of n points in the plane and a value r > 0, the unit-disk range reporting problem is to construct a data structure so that given any query disk of radius r, all points of P in the disk can be reported efficiently. We consider the dynamic version of the problem where point insertions and deletions of P are allowed. The previous best method provides a data structure of O(n log n) space that supports O(log^{3+ε} n) amortized insertion time, O(log^{5+ε} n) amortized deletion time, and O(log² n/log log n+k) query time, where ε is an arbitrarily small positive constant and k is the output size. In this paper, we improve the query time to O(log n+k) while keeping other complexities the same as before. A key ingredient of our approach is a shallow cutting algorithm for circular arcs, which may be interesting in its own right. A related problem that can also be solved by our techniques is the dynamic unit-disk range emptiness queries: Given a query unit disk, we wish to determine whether the disk contains a point of P. The best previous work can maintain P in a data structure of O(n) space that supports O(log² n) amortized insertion time, O(log⁴n) amortized deletion time, and O(log² n) query time. Our new data structure also uses O(n) space but can support each update in O(log^{1+ε} n) amortized time and support each query in O(log n) time
Computing the Minimum Bottleneck Moving Spanning Tree
Get PDFGiven a set P of n points that are moving in the plane, we consider the problem of computing a spanning tree for these moving points that does not change its combinatorial structure during the point movement. The objective is to minimize the bottleneck weight of the spanning tree (i.e., the largest Euclidean length of all edges) during the whole movement. The problem was solved in O(n²) time previously [Akitaya, Biniaz, Bose, De Carufel, Maheshwari, Silveira, and Smid, WADS 2021]. In this paper, we present a new algorithm of O(n^{4/3} log³ n) time
sj-pdf-1-sri-10.1177_15533506211057628 – Supplemental Material for Enhanced Recovery After Surgery in the Patients With Hepatocellular Carcinoma Undergoing Hemihepatectomy
No full textSupplemental Material, sj-pdf-1-sri-10.1177_15533506211057628 for Enhanced Recovery After Surgery in the Patients With Hepatocellular Carcinoma Undergoing Hemihepatectomy by Jiamin Zhou, Xigan He, Miao Wang, Yiming Zhao, Longrong Wang, Anrong Mao and Lu Wang in Surgical Innovation</p
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