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Spatial modulation (SM) is a promising multiple-input multiple-output system used to increase spectral efficiency. The maximum likelihood (ML) decoder jointly detects the transmitted SM symbol, which is of high complexity. In this paper, a…

Information Theory · Computer Science 2020-06-11 Ibrahim Al-Nahhal , Octavia A. Dobre , Salama Ikki

DBSCAN is a well-known density-based clustering algorithm to discover arbitrary shape clusters. While conceptually simple in serial, the algorithm is challenging to efficiently parallelize on manycore GPU architectures. Common pitfalls,…

Distributed, Parallel, and Cluster Computing · Computer Science 2023-06-30 Andrey Prokopenko , Damien Lebrun-Grandie , Daniel Arndt

We describe the two-dimensional TreePM method in this paper. The 2d TreePM code is an accurate and efficient technique to carry out large two-dimensional N-body simulations in cosmology. This hybrid code combines the 2d Barnes and Hut Tree…

Astrophysics · Physics 2009-11-10 Suryadeep Ray

Hypertree decompositions of hypergraphs are a generalization of tree decompositions of graphs. The corresponding hypertree-width is a measure for the cyclicity and therefore tractability of the encoded computation problem. Many NP-hard…

Data Structures and Algorithms · Computer Science 2008-10-12 Georg Gottlob , Marko Samer

Motion planning problems can be simplified by admissible projections of the configuration space to sequences of lower-dimensional quotient-spaces, called sequential simplifications. To exploit sequential simplifications, we present the…

Robotics · Computer Science 2019-08-27 Andreas Orthey , Marc Toussaint

Optimally selecting a subset of targets from a larger catalog is a common problem in astronomy and cosmology. A specific example is the selection of targets from an imaging survey for multi-object spectrographic follow-up. We present a new…

Astrophysics · Physics 2009-11-11 E. C. Elson , B. A. Bassett , K. van der Heyden , Z. Z. Vilakazi

We present a set of parallel algorithms for computing exact k-nearest neighbors in low dimensions. Many k-nearest neighbor algorithms use either a kd-tree or the Morton ordering of the point set; our algorithms combine these approaches…

Data Structures and Algorithms · Computer Science 2021-11-09 Magdalen Dobson , Guy Blelloch

The traditional algorithms do not meet the latest multiple requirements simultaneously for objects. Density-based method is one of the methodologies, which can detect arbitrary shaped clusters where clusters are defined as dense regions…

Databases · Computer Science 2016-12-05 Singh Vijendra , Priyanka Trikha

This paper describes the most efficient way to manage operations on ranges of elements within an ordered set. The goal is to improve existing solutions, by optimizing the average-case time complexity and getting rid of heavy multiplicative…

Data Structures and Algorithms · Computer Science 2021-10-18 Alberto Boffi

Measuring distances of cosmological sources such as galaxies, stars and quasars plays an increasingly critical role in modern cosmology. Obtaining the optical spectrum and consequently calculating the redshift as a distance indicator could…

Astrophysics of Galaxies · Physics 2022-01-13 Aidin Momtaz , Mohammad Hossein Salimi , Soroush Shakeri

The rooted tree is an important data structure, and the subtree size, height, and depth are naturally defined attributes of every node. We consider the problem of the existence of a k-ary tree given a list of attribute sequences. We give…

Data Structures and Algorithms · Computer Science 2016-07-19 Akshar Varma

Astronomy depends on ever increasing computing power. Processor clock-rates have plateaued, and increased performance is now appearing in the form of additional processor cores on a single chip. This poses significant challenges to the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Benjamin R. Barsdell , David G. Barnes , Christopher J. Fluke

In this paper, we present a deterministic variant of Chan's randomized partition tree [Discret. Comput. Geom., 2012]. This result leads to numerous applications. In particular, for $d$-dimensional simplex range counting (for any constant $d…

Computational Geometry · Computer Science 2025-07-03 Haitao Wang

We present several modifications to the previously proposed MSPP algorithm that can speed-up its execution considerably. The MSPP algorithm leverages a multiscale representation of the environment in $n$ dimensions. The information of the…

Data Structures and Algorithms · Computer Science 2016-02-16 Florian Hauer , Panagiotis Tsiotras

The observing strategy of a galaxy survey influences the degree to which its resulting data can be used to accomplish any science goal. LSST is thus seeking metrics of observing strategies for multiple science cases in order to optimally…

Instrumentation and Methods for Astrophysics · Physics 2021-04-19 Alex I. Malz , François Lanusse , John Franklin Crenshaw , Melissa L. Graham

DBSCAN is a fundamental spatial clustering algorithm with numerous practical applications. However, a bottleneck of the algorithm is in the worst case, the run time complexity is $O(n^2)$. To address this limitation, we propose a new…

Databases · Computer Science 2022-11-08 Xiaogang Huang , Tiefeng Ma , Conan Liu , Shuangzhe Liu

Clustering is widely used in different field such as biology, psychology, and economics. Most traditional clustering algorithms are limited to handling datasets that contain either numeric or categorical attributes. However, datasets with…

Databases · Computer Science 2019-07-03 Trupti M. Kodinariya Dr. Prashant R. Makwana

Customizable contraction hierarchies are one of the most popular route planning frameworks in practice, due to their simplicity and versatility. In this work, we present a novel algorithm for finding k-nearest neighbors in customizable…

Data Structures and Algorithms · Computer Science 2021-03-19 Valentin Buchhold , Dorothea Wagner

Earth imaging satellites are a crucial part of our everyday lives that enable global tracking of industrial activities. Use cases span many applications, from weather forecasting to digital maps, carbon footprint tracking, and vegetation…

Optimization tasks over relational data, such as clustering, often suffer from the prohibitive cost of join operations, which are necessary to access the full dataset. While geometric data structures like BBD trees yield fast approximation…

Databases · Computer Science 2026-03-13 Aryan Esmailpour , Stavros Sintos