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Under certain general conditions in an expanding universe, the luminosity distance (d_L) and angular diameter distance (d_A) are connected by the Etherington relation as d_L = d_A (1 + z)^2. The Tolman test suggests the use of objects of…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Satej Khedekar , Sayan Chakraborti

Many classical geometric inequalities on functionals of convex bodies depend on the dimension of the ambient space. We show that this dimension dependence may often be replaced (totally or partially) by different symmetry measures of the…

Metric Geometry · Mathematics 2014-12-11 René Brandenberg , Stefan König

The Procrustes distance is used to quantify the similarity or dissimilarity of (3-dimensional) shapes, and extensively used in biological morphometrics. Typically each (normalized) shape is represented by N landmark points, chosen to be…

Differential Geometry · Mathematics 2011-06-28 Yaron Lipman Reema Al-Aifari Ingrid Daubechies

The page written by the astronomer Francesco Bianchini (1662-1729) and containing the data of the 1701 winter solstice observed at Santa Maria degli Angeli is presented for the first time in figure 2 and widely discussed along this paper.…

History and Philosophy of Physics · Physics 2014-12-31 Costantino Sigismondi

Based on the double pendulum and Lagrange equation, the moving particles are captured by a binocular three-dimensional capture camera. Two trajectory models of Astrojax and the relationship between trajectory empirical formula and…

Physics Education · Physics 2022-01-25 Bin Duan , Zihao Bai , Yulong Zhang , Qingyuan Zhang , Sixing Fang , Bohui Shao

In 1651 Giovanni Riccioli reported the earliest accurate measurements the acceleration due to gravity, g, from pendulum-timed free fall experiments. The use of Huygens' pendulum formula (published 1673) allows one to deduce the pendulum…

History and Philosophy of Physics · Physics 2015-06-15 Patrick B. Warren

Prehistoric sanctuaries of Daunia date back several thousand years. During the Neolithic and Bronze Age the farmers in that region dug hypogea and holes whose characteristics suggest a ritual use. In the present note we summarize the…

History and Philosophy of Physics · Physics 2013-07-09 E. Antonello , V. F. Polcaro , A. M Tunzi Sisto , M. LoZupone

The measurement of distance between two objects is generalized to the case where the objects are no longer points but are one-dimensional. Additional concepts such as non-extensibility, curvature constraints, and non-crossing become central…

Soft Condensed Matter · Physics 2008-03-04 Steven S. Plotkin

Distance plays a fundamental role in measuring similarity between objects. Various visualization techniques and learning tasks in statistics and machine learning such as shape matching, classification, dimension reduction and clustering…

Machine Learning · Statistics 2025-04-23 Dianbin Bao , Kisung You , Lizhen Lin

The concept of pseudomagnitude was recently introduced by Chelli et al. (2016), to estimate apparent stellar diameters using a strictly observational methodology. Pseudomagnitudes are distance indicators, which have the remarkable property…

Solar and Stellar Astrophysics · Physics 2016-09-28 Alain Chelli , Gilles Duvert

A new way of probing the large-scale structure of the universe is proposed. Space is partitioned into cells the shape of rhombic dodecahedron. The cells are labelled ``filled'' or ``empty'' according as they contain galaxies or not. The…

Astrophysics · Physics 2014-10-13 T. Kiang

Knowing the distance of an astrophysical object is key to understanding it. However, at present, comparisons of theory and observations are hampered by precision (or lack thereof) in distance measurements or estimates. Putting the many…

Astrophysics of Galaxies · Physics 2015-06-11 Richard de Grijs

One of important components in an image retrieval system is selecting a distance measure to compute rank between two objects. In this paper, several distance measures were researched to implement a foliage plant retrieval system. Sixty…

Computer Vision and Pattern Recognition · Computer Science 2014-01-16 Abdul Kadir , Lukito Edi Nugroho , Adhi Susanto , Paulus Insap Santosa

To measure oscillation of a simple pendulum was probably a first idea coming to mind after appearance of smartphones with small but powerful acceleration sensors~: Simply attach the telephone to a playground swing or hang it on two string…

Physics Education · Physics 2020-05-12 Julien Vandermarlière , Mikhail Indenbom

We discuss the problem of how to calculate the distance between two cosmological objects given their redshifts and angular separation on the sky. Although of a fundamental nature, this problem and its solution seem to lack a detailed…

Astrophysics · Physics 2009-10-31 J. Liske

In the paper we will describe three instruments of particular historical and didactic interest belonging to the Historical Collection of Physics Instruments of Palermo University: a convex mirror most likely dating back to the early…

History and Philosophy of Physics · Physics 2021-12-28 Giovanni Luca Sferrazza , Aurelio Agliolo Gallitto

Graphs are interesting structures: extremely useful to depict real-life problems, extremely easy to understand given a sketch, extremely complicated to represent formally, extremely complicated to compare. Phylogeny is the study of the…

Data Structures and Algorithms · Computer Science 2019-01-18 Bernardo Lopo Tavares

Approximating distance is one of the key challenge in a facility location problem. Several algorithms have been proposed, however, none of them focused on estimating distance between two concave regions. In this work, we present an…

Optimization and Control · Mathematics 2018-06-12 Ruilin Ouyang , Dinghao Ma , M. S. Morshed , Md. Noor-E-Alam

A smartphone is a powerful learning aid in the hands of a large section of students around the world. The camera of the phone can be used for several learning purposes apart from its obvious purpose of photographing. If the focal length of…

Physics Education · Physics 2022-08-11 Soumen Sarkar , Sanjoy Kumar Pal , Surajit Chakrabarti

A stellar occultation occurs when a Solar System object passes in front of a star for an observer. This technique allows the determination of sizes and shapes of the occulting body with kilometer precision. Also, this technique constrains…