Quaternion Basics. Wikipedia (En)
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An Historical Review of the Theoretical Development of Rigid Body Displacements from Rodrigues Parameters to the finite Twist
Mechanism and Machine Theory Mechanism and Machine Theory 41 (2006) 41–52 www.elsevier.com/locate/mechmt An historical review of the theoretical development of rigid body displacements from Rodrigues parameters to the finite twist Jian S. Dai * Department of Mechanical Engineering, School of Physical Sciences and Engineering, King’s College London, University of London, Strand, London WC2R2LS, UK Received 5 November 2004; received in revised form 30 March 2005; accepted 28 April 2005 Available online 1 July 2005 Abstract The development of the finite twist or the finite screw displacement has attracted much attention in the field of theoretical kinematics and the proposed q-pitch with the tangent of half the rotation angle has dem- onstrated an elegant use in the study of rigid body displacements. This development can be dated back to RodriguesÕ formulae derived in 1840 with Rodrigues parameters resulting from the tangent of half the rota- tion angle being integrated with the components of the rotation axis. This paper traces the work back to the time when Rodrigues parameters were discovered and follows the theoretical development of rigid body displacements from the early 19th century to the late 20th century. The paper reviews the work from Chasles motion to CayleyÕs formula and then to HamiltonÕs quaternions and Rodrigues parameterization and relates the work to Clifford biquaternions and to StudyÕs dual angle proposed in the late 19th century. The review of the work from these mathematicians concentrates on the description and the representation of the displacement and transformation of a rigid body, and on the mathematical formulation and its progress. -
Scientific Contacts of Polish Physicists with Albert Einstein
The Global and the Local: The History of Science and the Cultural Integration of Europe. nd Proceedings of the 2 ICESHS (Cracow, Poland, September 6–9, 2006) / Ed. by M. Kokowski. Bronisław Średniawa * Scientific contacts of Polish physicists with Albert Einstein Abstract Scientific relations of Polish physicists, living in Poland and on emigration,with Albert Einstein, in the first half of 20th century are presented. Two Polish physicists, J. Laub and L. Infeld, were Einstein’s collaborators. The exchange of letters between M. Smoluchowski and Einstein contributed essentially to the solution of the problem of density fluctuations. S Loria, J. Kowalski, W. Natanson, M. Wolfke and L. Silberstein led scientific discussions with Einstein. Marie Skłodowska-Curie collaborated with Einstein in the Commission of Intelectual Cooperation of the Ligue of Nations. Einstein proposed scientific collaboration to M. Mathisson, but because of the breakout of the 2nd World War and Mathisson’s death their collaboration could not be realised. Contacts of Polish physicists with Einstein contributed to the development of relativity in Poland. (1) Introduction Many Polish physicists of older generation, who were active in Polish universities and abroad before the First World War or in the interwar period, had personal contacts with Einstein or exchanged letters with him. Contacts of Polish physicists with Einstein certainly inspired some Polish theoreticians to scientific work in relativity. These contacts encouraged also Polish physicists to make effort in the domain of popularization of relativity and of the progress of physics in the twenties and thirties. We can therefore say that the contacts of Polish physicists with Einstein contributed to the development of theoretical physics in Poland. -
The Orthogonal Planes Split of Quaternions and Its Relation to Quaternion Geometry of Rotations
Home Search Collections Journals About Contact us My IOPscience The orthogonal planes split of quaternions and its relation to quaternion geometry of rotations This content has been downloaded from IOPscience. Please scroll down to see the full text. 2015 J. Phys.: Conf. Ser. 597 012042 (http://iopscience.iop.org/1742-6596/597/1/012042) View the table of contents for this issue, or go to the journal homepage for more Download details: IP Address: 131.169.4.70 This content was downloaded on 17/02/2016 at 22:46 Please note that terms and conditions apply. 30th International Colloquium on Group Theoretical Methods in Physics (Group30) IOP Publishing Journal of Physics: Conference Series 597 (2015) 012042 doi:10.1088/1742-6596/597/1/012042 The orthogonal planes split of quaternions and its relation to quaternion geometry of rotations1 Eckhard Hitzer Osawa 3-10-2, Mitaka 181-8585, International Christian University, Japan E-mail: [email protected] Abstract. Recently the general orthogonal planes split with respect to any two pure unit 2 2 quaternions f; g 2 H, f = g = −1, including the case f = g, has proved extremely useful for the construction and geometric interpretation of general classes of double-kernel quaternion Fourier transformations (QFT) [7]. Applications include color image processing, where the orthogonal planes split with f = g = the grayline, naturally splits a pure quaternionic three-dimensional color signal into luminance and chrominance components. Yet it is found independently in the quaternion geometry of rotations [3], that the pure quaternion units f; g and the analysis planes, which they define, play a key role in the geometry of rotations, and the geometrical interpretation of integrals related to the spherical Radon transform of probability density functions of unit quaternions, as relevant for texture analysis in crystallography. -
Geometric Algebras for Euclidean Geometry
Geometric algebras for euclidean geometry Charles Gunn Keywords. metric geometry, euclidean geometry, Cayley-Klein construc- tion, dual exterior algebra, projective geometry, degenerate metric, pro- jective geometric algebra, conformal geometric algebra, duality, homo- geneous model, biquaternions, dual quaternions, kinematics, rigid body motion. Abstract. The discussion of how to apply geometric algebra to euclidean n-space has been clouded by a number of conceptual misunderstandings which we first identify and resolve, based on a thorough review of cru- cial but largely forgotten themes from 19th century mathematics. We ∗ then introduce the dual projectivized Clifford algebra P(Rn;0;1) (eu- clidean PGA) as the most promising homogeneous (1-up) candidate for euclidean geometry. We compare euclidean PGA and the popular 2-up model CGA (conformal geometric algebra), restricting attention to flat geometric primitives, and show that on this domain they exhibit the same formal feature set. We thereby establish that euclidean PGA is the smallest structure-preserving euclidean GA. We compare the two algebras in more detail, with respect to a number of practical criteria, including implementation of kinematics and rigid body mechanics. We then extend the comparison to include euclidean sphere primitives. We arXiv:1411.6502v4 [math.GM] 23 May 2016 conclude that euclidean PGA provides a natural transition, both scien- tifically and pedagogically, between vector space models and the more complex and powerful CGA. 1. Introduction Although noneuclidean geometry of various sorts plays a fundamental role in theoretical physics and cosmology, the overwhelming volume of practical science and engineering takes place within classical euclidean space En. For this reason it is of no small interest to establish the best computational model for this space. -
Euler's Square Root Laws for Negative Numbers
Ursinus College Digital Commons @ Ursinus College Transforming Instruction in Undergraduate Complex Numbers Mathematics via Primary Historical Sources (TRIUMPHS) Winter 2020 Euler's Square Root Laws for Negative Numbers Dave Ruch Follow this and additional works at: https://digitalcommons.ursinus.edu/triumphs_complex Part of the Curriculum and Instruction Commons, Educational Methods Commons, Higher Education Commons, and the Science and Mathematics Education Commons Click here to let us know how access to this document benefits ou.y Euler’sSquare Root Laws for Negative Numbers David Ruch December 17, 2019 1 Introduction We learn in elementary algebra that the square root product law pa pb = pab (1) · is valid for any positive real numbers a, b. For example, p2 p3 = p6. An important question · for the study of complex variables is this: will this product law be valid when a and b are complex numbers? The great Leonard Euler discussed some aspects of this question in his 1770 book Elements of Algebra, which was written as a textbook [Euler, 1770]. However, some of his statements drew criticism [Martinez, 2007], as we shall see in the next section. 2 Euler’sIntroduction to Imaginary Numbers In the following passage with excerpts from Sections 139—148of Chapter XIII, entitled Of Impossible or Imaginary Quantities, Euler meant the quantity a to be a positive number. 1111111111111111111111111111111111111111 The squares of numbers, negative as well as positive, are always positive. ...To extract the root of a negative number, a great diffi culty arises; since there is no assignable number, the square of which would be a negative quantity. Suppose, for example, that we wished to extract the root of 4; we here require such as number as, when multiplied by itself, would produce 4; now, this number is neither +2 nor 2, because the square both of 2 and of 2 is +4, and not 4. -
2 Homework Solutions 18.335 " Fall 2004
2 Homework Solutions 18.335 - Fall 2004 2.1 Count the number of ‡oating point operations required to compute the QR decomposition of an m-by-n matrix using (a) Householder re‡ectors (b) Givens rotations. 2 (a) See Trefethen p. 74-75. Answer: 2mn2 n3 ‡ops. 3 (b) Following the same procedure as in part (a) we get the same ‘volume’, 1 1 namely mn2 n3: The only di¤erence we have here comes from the 2 6 number of ‡opsrequired for calculating the Givens matrix. This operation requires 6 ‡ops (instead of 4 for the Householder re‡ectors) and hence in total we need 3mn2 n3 ‡ops. 2.2 Trefethen 5.4 Let the SVD of A = UV : Denote with vi the columns of V , ui the columns of U and i the singular values of A: We want to …nd x = (x1; x2) and such that: 0 A x x 1 = 1 A 0 x2 x2 This gives Ax2 = x1 and Ax1 = x2: Multiplying the 1st equation with A 2 and substitution of the 2nd equation gives AAx2 = x2: From this we may conclude that x2 is a left singular vector of A: The same can be done to see that x1 is a right singular vector of A: From this the 2m eigenvectors are found to be: 1 v x = i ; i = 1:::m p2 ui corresponding to the eigenvalues = i. Therefore we get the eigenvalue decomposition: 1 0 A 1 VV 0 1 VV = A 0 p2 U U 0 p2 U U 3 2.3 If A = R + uv, where R is upper triangular matrix and u and v are (column) vectors, describe an algorithm to compute the QR decomposition of A in (n2) time. -
A Fast Algorithm for the Recursive Calculation of Dominant Singular Subspaces N
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Journal of Computational and Applied Mathematics 218 (2008) 238–246 www.elsevier.com/locate/cam A fast algorithm for the recursive calculation of dominant singular subspaces N. Mastronardia,1, M. Van Barelb,∗,2, R. Vandebrilb,2 aIstituto per le Applicazioni del Calcolo, CNR, via Amendola122/D, 70126, Bari, Italy bDepartment of Computer Science, Katholieke Universiteit Leuven, Celestijnenlaan 200A, 3001 Leuven, Belgium Received 26 September 2006 Abstract In many engineering applications it is required to compute the dominant subspace of a matrix A of dimension m × n, with m?n. Often the matrix A is produced incrementally, so all the columns are not available simultaneously. This problem arises, e.g., in image processing, where each column of the matrix A represents an image of a given sequence leading to a singular value decomposition-based compression [S. Chandrasekaran, B.S. Manjunath, Y.F. Wang, J. Winkeler, H. Zhang, An eigenspace update algorithm for image analysis, Graphical Models and Image Process. 59 (5) (1997) 321–332]. Furthermore, the so-called proper orthogonal decomposition approximation uses the left dominant subspace of a matrix A where a column consists of a time instance of the solution of an evolution equation, e.g., the flow field from a fluid dynamics simulation. Since these flow fields tend to be very large, only a small number can be stored efficiently during the simulation, and therefore an incremental approach is useful [P. Van Dooren, Gramian based model reduction of large-scale dynamical systems, in: Numerical Analysis 1999, Chapman & Hall, CRC Press, London, Boca Raton, FL, 2000, pp. -
Combinatorial Design University of Southern California Non-Parametric Computational Design Strategies
Jose Sanchez Combinatorial design University of Southern California Non-parametric computational design strategies 1 ABSTRACT This paper outlines a framework and conceptualization of combinatorial design. Combinatorial 1 Design – Year 3 – Pattern of one design is a term coined to describe non-parametric design strategies that focus on the permutation, unit in two scales. Developed by combinatorial design within a game combination and patterning of discrete units. These design strategies differ substantially from para- engine. metric design strategies as they do not operate under continuous numerical evaluations, intervals or ratios but rather finite discrete sets. The conceptualization of this term and the differences with other design strategies are portrayed by the work done in the last 3 years of research at University of Southern California under the Polyomino agenda. The work, conducted together with students, has studied the use of discrete sets and combinatorial strategies within virtual reality environments to allow for an enhanced decision making process, one in which human intuition is coupled to algo- rithmic intelligence. The work of the research unit has been sponsored and tested by the company Stratays for ongoing research on crowd-sourced design. 44 INTRODUCTION—OUTSIDE THE PARAMETRIC UMBRELLA To start, it is important that we understand that the use of the terms parametric and combinatorial that will be used in this paper will come from an architectural and design background, as the association of these terms in mathematics and statistics might have a different connotation. There are certainly lessons and a direct relation between the term ‘combinatorial’ as used in this paper and the field of combinatorics and permutations in mathematics. -
The Book Review Column1 by William Gasarch Department of Computer Science University of Maryland at College Park College Park, MD, 20742 Email: [email protected]
The Book Review Column1 by William Gasarch Department of Computer Science University of Maryland at College Park College Park, MD, 20742 email: [email protected] In this column we review the following books. 1. Combinatorial Designs: Constructions and Analysis by Douglas R. Stinson. Review by Gregory Taylor. A combinatorial design is a set of sets of (say) {1, . , n} that have various properties, such as that no two of them have a large intersection. For what parameters do such designs exist? This is an interesting question that touches on many branches of math for both origin and application. 2. Combinatorics of Permutations by Mikl´osB´ona. Review by Gregory Taylor. Usually permutations are viewed as a tool in combinatorics. In this book they are considered as objects worthy of study in and of themselves. 3. Enumerative Combinatorics by Charalambos A. Charalambides. Review by Sergey Ki- taev, 2008. Enumerative combinatorics is a branch of combinatorics concerned with counting objects satisfying certain criteria. This is a far reaching and deep question. 4. Geometric Algebra for Computer Science by L. Dorst, D. Fontijne, and S. Mann. Review by B. Fasy and D. Millman. How can we view Geometry in terms that a computer can understand and deal with? This book helps answer that question. 5. Privacy on the Line: The Politics of Wiretapping and Encryption by Whitfield Diffie and Susan Landau. Review by Richard Jankowski. What is the status of your privacy given current technology and law? Read this book and find out! Books I want Reviewed If you want a FREE copy of one of these books in exchange for a review, then email me at gasarchcs.umd.edu Reviews need to be in LaTeX, LaTeX2e, or Plaintext. -
Blanchardstown Urban Structure Plan Development Strategy and Implementation
BLANCHARDSTOWN DEVELOPMENT STRATEGY URBAN STRUCTURE PLAN AND IMPLEMENTATION VISION, DEVELOPMENT THEMES AND OPPORTUNITIES PLANNING DEPARTMENT SPRING 2007 BLANCHARDSTOWN URBAN STRUCTURE PLAN DEVELOPMENT STRATEGY AND IMPLEMENTATION VISION, DEVELOPMENT THEMES AND OPPORTUNITIES PLANNING DEPARTMENT • SPRING 2007 David O’Connor, County Manager Gilbert Power, Director of Planning Joan Caffrey, Senior Planner BLANCHARDSTOWN URBAN STRUCTURE PLAN E DEVELOPMENT STRATEGY AND IMPLEMENTATION G A 01 SPRING 2007 P Contents Page INTRODUCTION . 2 SECTION 1: OBJECTIVES OF THE BLANCHARDSTOWN URBAN STRUCTURE PLAN – DEVELOPMENT STRATEGY 3 BACKGROUND PLANNING TO DATE . 3 VISION STATEMENT AND KEY ISSUES . 5 SECTION 2: DEVELOPMENT THEMES 6 INTRODUCTION . 6 THEME: COMMERCE RETAIL AND SERVICES . 6 THEME: SCIENCE & TECHNOLOGY . 8 THEME: TRANSPORT . 9 THEME: LEISURE, RECREATION & AMENITY . 11 THEME: CULTURE . 12 THEME: FAMILY AND COMMUNITY . 13 SECTION 3: DEVELOPMENT OPPORTUNITIES – ESSENTIAL INFRASTRUCTURAL IMPROVEMENTS 14 SECTION 4: DEVELOPMENT OPPORTUNITY AREAS 15 Area 1: Blanchardstown Town Centre . 16 Area 2: Blanchardstown Village . 19 Area 3: New District Centre at Coolmine, Porterstown, Clonsilla . 21 Area 4: Blanchardstown Institute of Technology and Environs . 24 Area 5: Connolly Memorial Hospital and Environs . 25 Area 6: International Sports Campus at Abbotstown. (O.P.W.) . 26 Area 7: Existing and Proposed District & Neighbourhood Centres . 27 Area 8: Tyrrellstown & Environs Future Mixed Use Development . 28 Area 9: Hansfield SDZ Residential and Mixed Use Development . 29 Area 10: North Blanchardstown . 30 Area 11: Dunsink Lands . 31 SECTION 5: RECOMMENDATIONS & CONCLUSIONS 32 BLANCHARDSTOWN URBAN STRUCTURE PLAN E G DEVELOPMENT STRATEGY AND IMPLEMENTATION A 02 P SPRING 2007 Introduction Section 1 details the key issues and need for an Urban Structure Plan – Development Strategy as the planning vision for the future of Blanchardstown. -
A2241: Clusters with Head-Tails at X-Rays L. Norci
A2241: CLUSTERS WITH HEAD-TAILS AT X-RAYS L. NORCI Dunsink Observatory Castleknock, Dublin 15, Ireland L. FERETTI Istituto di Radio Astronomia Via Gobetti 101, 1-40129 Bologna, Italy AND E.J.A. MEURS Dunsink Observatory Castleknock, Dublin 15, Ireland Abstract. A ROSAT Ρ SPC image of the galaxy cluster Abell 2241 has been obtained, showing X-ray emission from the intracluster medium and from individual objects. The brightness distribution of the cluster gas is used to assess the physical conditions at the location of two tailed radio galaxies (in A2241E and A2241W, at different redshifts). Together with radio and X-ray information on the two galaxies themselves the results are of relevance to the question of energy equipartition in radio sources. 1. Background A cluster intergalactic medium plays an important role in determining the morphology and evolution of radio sources. The external gas can interact with a radio source in different ways: confining the source, modifying the source morphology via ram-pressure and possibly feeding the active nucleus. We have obtained ROSAT X-ray data of the region of the cluster Abell 2241, which was previously studied by Bijleveld & Valentijn (1982). A2241 was originally classified as an irregular galaxy cluster, until redshift mea- surements showed it to consist of two separate clusters projected onto each other: A2241W and A2241E, located at redshifts of 0.0635 and 0.1021, respectively. 361 R. Ekers et al. (eds.), Extragalactic Radio Sources, 361-362. © 1996 IAU. Printed in the Netherlands. Downloaded from https://www.cambridge.org/core. IP address: 170.106.33.14, on 29 Sep 2021 at 08:43:38, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. -
Macfarlane Hyperbolic 3-Manfiolds
MACFARLANE HYPERBOLIC 3-MANIFOLDS JOSEPH A. QUINN Abstract. We identify and study a class of hyperbolic 3-manifolds (which we call Mac- farlane manifolds) whose quaternion algebras admit a geometric interpretation analogous to Hamilton's classical model for Euclidean rotations. We characterize these manifolds arithmetically, and show that infinitely many commensurability classes of them arise in diverse topological and arithmetic settings. We then use this perspective to introduce a new method for computing their Dirichlet domains. We give similar results for a class of hyperbolic surfaces and explore their occurrence as subsurfaces of Macfarlane manifolds. 1. Introduction Quaternion algebras over complex number fields arise as arithmetic invariants of com- plete orientable finite-volume hyperbolic 3-manifolds [16]. Quaternion algebras over totally real number fields are similarly associated to immersed totally-geodesic hyperbolic subsur- faces of these manifolds [16, 28]. The arithmetic properties of the quaternion algebras can be analyzed to yield geometric and topological information about the manifolds and their commensurability classes [17, 20]. In this paper we introduce an alternative geometric interpretation of these algebras, re- calling that they are a generalization of the classical quaternions H of Hamilton. In [22], the author elaborated on a classical idea of Macfarlane [15] to show how an involution on the complex quaternion algebra can be used to realize the action of Isom`pH3q multiplica- tively, similarly to the classical use of the standard involution on H to realize the action of Isom`pS2q. Here we generalize this to a class of quaternion algebras over complex number fields and characterize them by an arithmetic condition.