Auswahl der wissenschaftlichen Literatur zum Thema „Frame Invariance“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Inhaltsverzeichnis
Machen Sie sich mit den Listen der aktuellen Artikel, Bücher, Dissertationen, Berichten und anderer wissenschaftlichen Quellen zum Thema "Frame Invariance" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Zeitschriftenartikel zum Thema "Frame Invariance"
1
Fernández Cristóbal, José Ma. „Weyl invariance in metric f(R) gravity“. Revista Mexicana de Física 64, Nr. 2 (14.03.2018): 181. http://dx.doi.org/10.31349/revmexfis.64.181.
Der volle Inhalt der QuelleAnnotation:
We aim to derive the most general f(R) gravity theory, including thematter, so that it be Weyl invariant. Making use of the mathematicalequivalence of these theories with an type of scalar-tensor theory, and byimposing the Weyl invariance for the pure gravity as well as for the mattersector, we obtain the fundamental equation that restricts the form of V (phi) (and, accordingly, of f(R)) so that the resulting action to be Weylinvariant in the Jordan frame. We show that this action is not otherthan the so-called dilaton gravity action with one scalar eld,, whicheective mass is R and Phi dependent. In the Einstein frame, the actionbecomes the Einstein-Hilbert action with the Ricci scalar being constantdue to that the eective mass of scalar eld in this frame vanish. So,we can assume that the Ricci scalar, in the Einstein frame, is the trueCosmological Constant. Therefore, is not preposterous to guess that, atleast mathematically, all Weyl invariant metric f(R) theory in the Jordanframe is equivalent, at classical level, to the Einstein gravity, in theEinstein frame, with a constant Ricci scalar. At quantum level, as it isknown, both theories are not equivalent due to the presence of anomaliesin one of the frames.
2
Stuckey, William, Timothy McDevitt und Michael Silberstein. „No Preferred Reference Frame at the Foundation of Quantum Mechanics“. Entropy 24, Nr. 1 (22.12.2021): 12. http://dx.doi.org/10.3390/e24010012.
Der volle Inhalt der QuelleAnnotation:
Quantum information theorists have created axiomatic reconstructions of quantum mechanics (QM) that are very successful at identifying precisely what distinguishes quantum probability theory from classical and more general probability theories in terms of information-theoretic principles. Herein, we show how one such principle, Information Invariance and Continuity, at the foundation of those axiomatic reconstructions, maps to “no preferred reference frame” (NPRF, aka “the relativity principle”) as it pertains to the invariant measurement of Planck’s constant h for Stern-Gerlach (SG) spin measurements. This is in exact analogy to the relativity principle as it pertains to the invariant measurement of the speed of light c at the foundation of special relativity (SR). Essentially, quantum information theorists have extended Einstein’s use of NPRF from the boost invariance of measurements of c to include the SO(3) invariance of measurements of h between different reference frames of mutually complementary spin measurements via the principle of Information Invariance and Continuity. Consequently, the “mystery” of the Bell states is understood to result from conservation per Information Invariance and Continuity between different reference frames of mutually complementary qubit measurements, and this maps to conservation per NPRF in spacetime. If one falsely conflates the relativity principle with the classical theory of SR, then it may seem impossible that the relativity principle resides at the foundation of non-relativisitic QM. In fact, there is nothing inherently classical or quantum about NPRF. Thus, the axiomatic reconstructions of QM have succeeded in producing a principle account of QM that reveals as much about Nature as the postulates of SR.
3
Münch, Ingo, und Patrizio Neff. „Rotational invariance conditions in elasticity, gradient elasticity and its connection to isotropy“. Mathematics and Mechanics of Solids 23, Nr. 1 (26.09.2016): 3–42. http://dx.doi.org/10.1177/1081286516666134.
Der volle Inhalt der QuelleAnnotation:
For homogeneous higher-gradient elasticity models we discuss frame-indifference and isotropy requirements. To this end, we introduce the notions of local versus global SO(3)-invariance and identify frame-indifference (traditionally) with global left SO(3)-invariance and isotropy with global right SO(3)-invariance. For specific restricted representations, the energy may also be local left SO(3)-invariant as well as local right SO(3)-invariant. Then we turn to linear models and consider a consequence of frame-indifference together with isotropy in nonlinear elasticity and apply this joint invariance condition to some specific linear models. The interesting point is the appearance of finite rotations in transformations of a geometrically linear model. It is shown that when starting with a linear model defined already in the infinitesimal symmetric strain [Formula: see text], the new invariance condition is equivalent to the isotropy of the linear formulation. Therefore, it may also be used in higher-gradient elasticity models for a simple check of isotropy and for extensions to anisotropy. In this respect we consider in more detail variational formulations of the linear indeterminate couple-stress model, a new variant of it with symmetric force stresses and general linear gradient elasticity.
4
Choi, Jinsoo, und Tae-Hyun Oh. „Joint Video Super-Resolution and Frame Interpolation via Permutation Invariance“. Sensors 23, Nr. 5 (24.02.2023): 2529. http://dx.doi.org/10.3390/s23052529.
Der volle Inhalt der QuelleAnnotation:
We propose a joint super resolution (SR) and frame interpolation framework that can perform both spatial and temporal super resolution. We identify performance variation according to permutation of inputs in video super-resolution and video frame interpolation. We postulate that favorable features extracted from multiple frames should be consistent regardless of input order if the features are optimally complementary for respective frames. With this motivation, we propose a permutation invariant deep architecture that makes use of the multi-frame SR principles by virtue of our order (permutation) invariant network. Specifically, given two adjacent frames, our model employs a permutation invariant convolutional neural network module to extract “complementary” feature representations facilitating both the SR and temporal interpolation tasks. We demonstrate the effectiveness of our end-to-end joint method against various combinations of the competing SR and frame interpolation methods on challenging video datasets, and thereby we verify our hypothesis.
5
Xu, Zhenheng, Guoqing Hong, Zuhua Guo und Jianxia Zhang. „Quantum Injectivity of Frames in Quaternionic Hilbert Spaces“. Mathematics 12, Nr. 14 (11.07.2024): 2174. http://dx.doi.org/10.3390/math12142174.
Der volle Inhalt der QuelleAnnotation:
A quantum injective frame is a frame capable of differentiating states based on their respective frame measurements, whereas the quantum-detection problem associated with frames endeavors to delineate all such frames. In the present paper, the concept of injective frames in infinite dimensional quaternionic Hilbert spaces is introduced. Further, some properties of injective frames such as the invariance of injective frames under invertible operators are discussed and several solutions to the frame quantum-detection problem are given. Finally, by employing operator theory and frames theory in quaternionic Hilbert spaces, some characterizations and classifications of frames for solving the injectivity problem are given.
6
Basso, Marcos L. W., und Jonas Maziero. „Complete complementarity relations and their Lorentz invariance“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 477, Nr. 2253 (September 2021): 20210058. http://dx.doi.org/10.1098/rspa.2021.0058.
Der volle Inhalt der QuelleAnnotation:
It is well known that entanglement under Lorentz boosts is highly dependent on the boost scenario in question. For single-particle states, a spin-momentum product state can be transformed into an entangled state. However, entanglement is just one of the aspects that completely characterizes a quantum system. The other two are known as the wave-particle duality. Although the entanglement entropy does not remain invariant under Lorentz boosts, and neither do the measures of predictability and coherence, we show here that these three measures taken together, in a complete complementarity relation (CCR), are Lorentz invariant. Peres et al. (Peres et al. 2002 Phys. Rev. Lett. 88 , 230402. ( doi:10.1103/PhysRevLett.88.230402 )) realized that even though it is possible to formally define spin in any Lorentz frame, there is no relationship between the observable expectation values in different Lorentz frames. Analogously, one can, in principle, define complementary relations in any Lorentz frame, but there is no obvious transformation law relating complementary relations in different frames. However, our result shows that the CCRs have the same value in any Lorentz frame, i.e. there is a transformation law connecting the CCRs. In addition, we explore relativistic scenarios for single and two-particle states, which helps in understanding the exchange of different aspects of a quantum system under Lorentz boosts.
7
Thomas, T. G., und H. S. Takhar. „Frame-invariance of turbulence constitutive relations“. Astrophysics and Space Science 141, Nr. 1 (1988): 159–68. http://dx.doi.org/10.1007/bf00641922.
Der volle Inhalt der Quelle
8
Romano, Giovanni, und Raffaele Barretta. „Geometric constitutive theory and frame invariance“. International Journal of Non-Linear Mechanics 51 (Mai 2013): 75–86. http://dx.doi.org/10.1016/j.ijnonlinmec.2012.12.006.
Der volle Inhalt der Quelle
9
FREWER, MICHAEL. „Proper invariant turbulence modelling within one-point statistics“. Journal of Fluid Mechanics 639 (13.10.2009): 37–64. http://dx.doi.org/10.1017/s0022112009991133.
Der volle Inhalt der QuelleAnnotation:
A new turbulence modelling approach is presented. Geometrically reformulating the averaged Navier–Stokes equations on a four-dimensional non-Riemannian manifold without changing the physical content of the theory, additional modelling restrictions which are absent in the usual Euclidean (3+1)-dimensional framework naturally emerge. The modelled equations show full form invariance for all Newtonian reference frames in that all involved quantities transform as true 4-tensors. Frame accelerations or inertial forces of any kind are universally described by the underlying four-dimensional geometry.By constructing a nonlinear eddy viscosity model within the k−ϵ family for high turbulent Reynolds numbers the new invariant modelling approach demonstrates the essential advantages over current (3+1)-dimensional modelling techniques. In particular, new invariants are gained, which allow for a universal and consistent treatment of non-stationary effects within a turbulent flow. Furthermore, by consistently introducing via a Lie-group symmetry analysis a new internal modelling variable, the mean form-invariant pressure Hessian, it will be shown that already a quadratic nonlinearity is sufficient to capture secondary flow effects, for which in current nonlinear eddy viscosity models a higher nonlinearity is needed. In all, this paper develops a new unified formalism which will naturally guide the way in physical modelling whenever reasonings are based on the general concept of invariance.
10
Basso, E., und Daniel J. H. Chung. „Lorentz invariance of basis tensor gauge theory“. International Journal of Modern Physics A 36, Nr. 17 (07.06.2021): 2150099. http://dx.doi.org/10.1142/s0217751x21500998.
Der volle Inhalt der QuelleAnnotation:
Basis tensor gauge theory (BTGT) is a vierbein analog reformulation of ordinary gauge theories in which the vierbein field describes the Wilson line. After a brief review of the BTGT, we clarify the Lorentz group representation properties associated with the variables used for its quantization. In particular, we show that starting from an SO(1,3) representation satisfying the Lorentz-invariant U(1,3) matrix constraints, BTGT introduces a Lorentz frame choice to pick the Abelian group manifold generated by the Cartan subalgebra of U(1,3) for the convenience of quantization even though the theory is frame independent. This freedom to choose a frame can be viewed as an additional symmetry of BTGT that was not emphasized before. We then show how an [Formula: see text] permutation symmetry and a parity symmetry of frame fields natural in BTGT can be used to construct renormalizable gauge theories that introduce frame-dependent fields but remain frame independent perturbatively without any explicit reference to the usual gauge field.
Dissertationen zum Thema "Frame Invariance"
1
Lundgren, Martin. „Bending, Twisting and Turning : Protein Modeling and Visualization from a Gauge-Invariance Viewpoint“. Doctoral thesis, Uppsala universitet, Teoretisk fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-172358.
Der volle Inhalt der QuelleAnnotation:
Proteins in nature fold to one dominant native structure. Despite being a heavily studied field, predicting the native structure from the amino acid sequence and modeling the folding process can still be considered unsolved problems. In this thesis I present a new approach to this problem with methods borrowed from theoretical physics. In the first part I show how it is possible to use a discrete Frenet frame to define the discrete curvature and torsion of the main chain of the protein. This method is then extended to the side chains as well. In particular I show how to use the discrete Frenet frame to produce a statistical distribution of angles that works in similar fashion as the commonly used Ramachandran plot and side chain rotamers. The discrete Frenet frame displays a gauge symmetry, in the choice of basis vectors on the normal plane, that is reminiscent of features of Abelian-Higgs theory. In the second part of the thesis I show how this similarity with Abelian-Higgs theory can be translated into an effective energy for a protein. The loops of the proteins are shown to correspond to solitons so that the whole protein can be constructed by gluing together any number of solitons. I present results of simulating proteins by minimizing the energy, starting from a real line or straight helix, where the correct native fold is attained. Finally the model is shown to display the same phase structure as real proteins.
2
Tetelin, Arthur. „Reconstruction des variables vectorielles dans le cadre des méthodes volumes finis sur maillages non-structurés généraux“. Electronic Thesis or Diss., Toulouse, ISAE, 2024. http://www.theses.fr/2024ESAE0029.
Der volle Inhalt der QuelleAnnotation:
Les simulations numériques dans le domaine de l’énergétique peuvent présenter de forts gradients et des discontinuités, ainsi qu’une forte disparité d’échelles spatiales et temporelles. C’est typiquement le cas des simulations menées avec le code Cedre, développé par le département multi-physique pour l’énergétique de l’ONERA. Il est donc nécessaire de développer des méthodes numériques précises, robustes et performantes. Dans ce cadre, la reconstruction des variables aux faces des volumes de contrôle est l’un des éléments clé de la résolution des équations de conservation hyperboliques dans les approches volumes finis. Ces reconstructions permettent en effet d’améliorer la précision du calcul des flux numériques, ce qui a une influence majeure sur la précision globale du schéma. En outre, il est bien connu qu’une reconstruction linéaire ne suffit pas à assurer la stabilité du schéma dans le cas général, ce qui nécessite l’utilisation de reconstructions limitées. Si la reconstructions des variables scalaires a fait l’objet d’un grand nombre de travaux ces dernières décennies, très peu d’études se sont jusqu’à présent intéressées aux reconstructions des variables vectorielles. La plupart des approches des codes de calculs industriels comme Cedre consiste en effet à reconstruire chaque composante des vecteurs indépendamment des autres avec une approche scalaire. Néanmoins, une telle approche se révèle être dépendante du repère : la solution obtenue change en fonction du repère choisi, engendrant divers problèmes de précision ou de conservation sur des maillages présentant des frontières périodiques par rotation. L’objectif de cette thèse est donc double. Il vise dans un premier temps à étudier théoriquement la précision et la stabilité des reconstructions vectorielles, puis dans un second temps à développer une méthode de reconstruction vectorielle de type MUSCL multipente qui soit efficace, précise et robuste. Pour cela, nous introduisons les κ-schémas limités, qui permettent d’obtenir une reconstruction d’ordre 2 invariante par rotation, et facilement adaptable à n’importe quelle condition de monotonie choisie. Nous introduisons aussi la notion de reconstruction fictive afin d’obtenir une écriture du schéma mettant en évidence ses propriétés de stabilité. Nous en déduisons deux conditions de monotonie adaptées aux variables vectorielles, que nous éprouvons ensuite sur différents cas-tests numériques. Enfin, nous présentons une troisième approche, basée sur l’extension directe de la condition de monotonie du cas scalaire vers le cas vectoriel. Bien qu’aucune preuve de stabilité n’ait pu être écrite pour cette approche, elle présente tout de même le meilleur compromis entre stabilité d’une part, et précision et efficacité d’autre partNumerical simulations in the field of energetics often present sharp gradients or discontinuities, as well as strong disparity of spatial and temporal scales. This is typical of simulations runned with Cedre software, developed by ONERA’s Multi-physics department for energetics. All these features involve the development of accurate, robust and efficient numerical methods. In this framework, variable reconstruction is one of the key aspects of the resolution of hyperbolic conservation laws in finite volume methods. These reconstructions improve the accuracy of the numerical fluxes, which has a direct impact on the spatial accuracy of the scheme. Moreover, it is well known that a linear reconstruction is not sufficient to ensure the scheme stability. Thus, non-linear reconstructions are required. While scalar variables reconstructions have been intensively studied during the last decades, very few studies have been conducted on vectorial variable reconstructions. In industrial codes like Cedre, each component of vectorial variables is usually treated independently as a scalar variable. However, such an approach reveals to be frame-dependent : the solution is dependent on the frame, leading to conservation and accuracy problems on periodical meshes. This thesis therefore focuses on two aspects. Firstly, it aims to study theoretically the accuracy and stability of vectorial reconstructions, and secondly to develop a vectorial reconstruction method designed for the multislope MUSCL scheme, being efficient, accurate and robust. To do so, we introduce limited κ-schemes, allowing to obtain a second-order accurate frame-invariant reconstruction, easily adaptable to any monotone condition chosen. We also introduce fictitious reconstructions, allowing to get a formulation of the scheme highlighting its stability properties. We deduce from it two monotonicity definitions suitable for vectors, that we then run on different numerical test-cases. Lastly, we present a third approach, based on the direct extension of the scalar monotonicity condition to the vectorial case. Even if no stability proof has been written, this approach presents the best compromise between stability and accuracy
3
Savi, Matheus Fritsch. „Elements of modern physics within lightweight reference frames : time contraction and quantumness invariance“. reponame:Repositório Institucional da UFPR, 2017. http://hdl.handle.net/1884/49398.
Der volle Inhalt der QuelleAnnotation:
Orientador: Prof. Dr. Renato M. AngeloDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Física. Defesa: Curitiba, 28/07/2017
Inclui referências : f. 90-95
Resumo: Para percebermos como a noção de referencial é importante, considere a seguinte questão: qual seria a física de uma partícula num universo vazio? Qual seria sua velocidade, carga, temperatura, ou função de onda? Como seria sua evolução temporal? Embora seja um dos elementos mais básicos e fundamentais de uma teoria física, a não de referencial quase nunca é rigorosamente definida. Muitas vezes confunde-se com a noção de sistemas de coordenadas, uma entidade matemática abstrata e desprovida de substancia física. Um físico experimental, no entanto, tem a firme tendência de desaprovar esta noção. Por conseguinte, no final do século 20 e em anos recentes, alguns trabalhos investigaram a física descrita da perspectiva de referenciais físicos, de massa finita e interagentes. Entretanto, o conhecimento acumulado até o momento sobre este tópico, especialmente nas áreas de Relatividade Especial e Mecânica Quântica, é incipiente. Neste trabalho pretendemos contribuir para este contexto através de dois estudos preliminares em modelos simples da Física Moderna. Na primeira parte desta dissertação, revisitamos o problema da dilatação do tempo, onde atribuímos ao laboratório uma massa arbitrária de modo a participar das leis de conservação, pois este 'e capaz de "sentir" a emissão de um fóton; esta consideração acentua a fórmula usual por um fator adimensional envolvendo a constante de Planck. Na segunda parte, abordamos uma questão fundamental, qual seja: é a quanticidade total de recursos quânticos - coerências e correlações - invariante sob troca de referenciais quânticos? Nosso estudo 'e realizado em sistemas de poucas partículas onde, primeiramente, construímos e tratamos um modelo clássico "análogo" ao caso quântico para então tratarmos este 'ultimo; consideramos estados de posição e de spin descritos por referenciais distintos e avaliamos como os recursos comportam-se em cada referencial. Apesar da simplicidade dos modelos considerados, acreditamos que nossos resultados já sejam capazes de revelar aspectos sutis e importantes, merecendo então uma investigação mais aprofundada. Palavras-chave: relatividade especial, contração do tempo, referenciais leves, referenciais quânticos, correlações quânticas e coerência, spin relativo.
Abstract: In order to realize how the notion of reference frame is important, consider the following question: what would be the physics of a particle in an empty universe? What would its velocity, charge, temperature, or wave function be? What about its time evolution? Although it is one of the most basic and fundamental elements of a physical theory, the notion of reference frame is almost never rigorously defined. It is frequently confused with the notion of a coordinate system, an abstract mathematical entity devoid of physical significance. An experimental physicist, however, has the strong tendency to disapprove this notion. Therefore, at the end of the 20th century and in recent years, some works have investigated the physics described from the perspective of physical reference frames, of finitemass and interacting ones. However, the accumulated knowledge hitherto about this topic, specially in Special Relativity and Quantum Mechanics, is incipient. In this work we intend to contribute to this context through two preliminary studies regarding simple models from Modern Physics. In the first part of this dissertation, we revisit the time dilation problem, where we attribute to the laboratory an arbitrary mass so as to participate in the conservation laws, for it is able to "feel" the emission of a photon; this consideration accentuates the usual formula by a dimensionless factor involving the Planck constant. In the second part, we approach a fundamental question, which is: is the total quantumness of quantum resources - coherences and correlations - invariant under change of quantum reference frames? Our study is realized in systems composed of few particles where, firstly, we construct and treat a classical model which is "analog" to the quantum case and only then we attend to the latter; we consider position and spin states described by distinct reference frames and evaluate how the resources behave in each frame. Despite of the simplicity of the approached models, we believe that our results are already able to reveal subtle and important aspects, deserving then a more profound investigation. Keywords: special relativity, time contraction, lightweight reference frames, quantum reference frames, quantum correlations and coherence, relative spin.
4
Mkhaliphi, Mkhuseli Bruce. „Reconstruction of Functions From Non-uniformly Distributed Sampled Data in Shift-Invariant Frame Subspaces“. Master's thesis, Faculty of Engineering and the Built Environment, 2018. http://hdl.handle.net/11427/30079.
Der volle Inhalt der QuelleAnnotation:
The focus of this research is to study and implement efficient iterative reconstruction algorithms. Iterative reconstruction algorithms are used to reconstruct bandlimited signals in shift-invariant L2 subspaces from a set of non-uniformly distributed sampled data. The Shannon-Whittaker reconstruction formula commonly used in uniform sampling problems is insufficient in reconstructing function from non-uniformly distributed sampled data. Therefore new techniques are required. There are many traditional approaches for non-uniform sampling and reconstruction methods where the Adaptive Weights (AW) algorithm is considered to be the most efficient. Recently, the Partitions of Unity (PoU) algorithm has been suggested to outperform the AW although there has been much literature covering its numerical performance. A study and analysis of the implementation of the Adaptive Weights (AW) and Partitions of Unity (PoU) reconstruction methods is conducted. The algorithms consider the missing data problem, defined as reconstructing continuous-time (CT) signals from non-uniform samples which resulted from missing samples on a uniform grid. Mainly, the algorithms convert the non-uniform grid to a uniform grid. The implemented iterative methods construct CT bandlimited functions in frame subspaces. Bandlimited functions are considered to be a superposition of basis functions, named frames. PoU is a variation of AW, they differ by the choice of frame because each frame produces a different approximation operator and convergence rate. If efficiency is defined as the norm convergence and computational time of an algorithm, then among the two methods, discussed, the PoU method is more efficient. The AW method is slow and converged to a higher error than that of the PoU. However, AW compensates for its slowness and less accuracy by being convergent and robust for large sampling gaps and less sensitive to the sampling irregularities. The impact of additive white Gaussian noise on the performance of the two algorithms is also investigated. The numerical tools utilized in this research consist of the theory of discrete irregular sampling, frames, and iterative techniques. The developed software provides a platform for sampling signals under non-ideal conditions with real devices.
5
Andreescu, Oana Fabiana. „Static analysis of functional programs with an application to the frame problem in deductive verification“. Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S047/document.
Der volle Inhalt der QuelleAnnotation:
Dans le domaine de la vérification formelle de logiciels, il est impératif d'identifier les limites au sein desquelles les éléments ou fonctions opèrent. Ces limites constituent les propriétés de frame (frame properties en anglais). Elles sont habituellement spécifiées manuellement par le programmeur et leur validité doit être vérifiée: il est nécessaire de prouver que les opérations du programme n'outrepassent pas les limites ainsi déclarées. Dans le contexte de la vérification formelle interactive de systèmes complexes, comme les systèmes d'exploitation, un effort considérable est investi dans la spécification et la preuve des propriétés de frame. Cependant, la plupart des opérations ont un effet très localisé et ne menacent donc qu'un nombre limité d'invariants. Étant donné que la spécification et la preuve de propriétés de frame est une tache fastidieuse, il est judicieux d'automatiser l'identification des invariants qui ne sont pas affectés par une opération donnée. Nous présentons dans cette thèse une solution inférant automatiquement leur préservation. Notre solution a pour but de réduire le nombre de preuves à la charge du programmeur. Elle est basée sur l'analyse statique, et ne nécessite aucune annotation de frame. Notre stratégie consiste à combiner une analyse de dépendances avec une analyse de corrélations. Nous avons conçu et implémenté ces deux analyses statiques pour un langage fonctionnel fortement typé qui manipule structures, variants et tableaux. Typiquement, une propriété fonctionnelle ne dépend que de quelques fragments de l'état du programme. L'analyse de dépendances détermine quelles parties de cet état influent sur le résultat de la propriété fonctionnelle. De même, une fonction ne modifiera que certaines parties de ses arguments, copiant le reste à l'identique. L'analyse de corrélations détecte quelles parties de l'entrée d'une fonction se retrouvent copiées directement (i.e. non modifiés) dans son résultat. Ces deux analyses calculent une approximation conservatrice. Grâce aux résultats de ces deux analyses statiques, un prouveur de théorèmes interactif peut inférer automatiquement la préservation des invariants qui portent sur la partie non affectée par l’opération concernée. Nous avons appliqué ces deux analyses statiques à la spécification fonctionnelle d'un micro-noyau, et obtenu des résultats non seulement d'une précision adéquate, mais qui montrent par ailleurs que notre approche peut passer à l'échelleIn the field of software verification, the frame problem refers to establishing the boundaries within which program elements operate. It has notoriously tedious consequences on the specification of frame properties, which indicate the parts of the program state that an operation is allowed to modify, as well as on their verification, i.e. proving that operations modify only what is specified by their frame properties. In the context of interactive formal verification of complex systems, such as operating systems, much effort is spent addressing these consequences and proving the preservation of the systems' invariants. However, most operations have a localized effect on the system and impact only a limited number of invariants at the same time. In this thesis we address the issue of identifying those invariants that are unaffected by an operation and we present a solution for automatically inferring their preservation. Our solution is meant to ease the proof burden for the programmer. It is based on static analysis and does not require any additional frame annotations. Our strategy consists in combining a dependency analysis and a correlation analysis. We have designed and implemented both static analyses for a strongly-typed, functional language that handles structures, variants and arrays. The dependency analysis computes a conservative approximation of the input fragments on which functional properties and operations depend. The correlation analysis computes a safe approximation of the parts of an input state to a function that are copied to the output state. It summarizes not only what is modified but also how it is modified and to what extent. By employing these two static analyses and by subsequently reasoning based on their combined results, an interactive theorem prover can automate the discharching of proof obligations for unmodified parts of the state. We have applied both of our static analyses to a functional specification of a micro-kernel and the obtained results demonstrate both their precision and their scalability
6
Iverson, Joseph. „Frames Generated by Actions of Locally Compact Groups“. Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20443.
Der volle Inhalt der QuelleAnnotation:
Let $G$ be a second countable, locally compact group which is either compact or abelian, and let $\rho$ be a unitary representation of $G$ on a separable Hilbert space $\mathcal{H}_\rho$. We examine frames of the form $\{ \rho(x) f_j \colon x \in G, j \in I\}$ for families $\{f_j\}_{j \in I}$ in $\mathcal{H}_\rho$. In particular, we give necessary and sufficient conditions for the joint orbit of a family of vectors in $\mathcal{H}_\rho$ to form a continuous frame.
We pay special attention to this problem in the setting of shift invariance. In other words, we fix a larger second countable locally compact group $\Gamma \supset G$ containing $G$ as a closed subgroup, and we let $\rho$ be the action of $G$ on $L^2(\Gamma)$ by left translation. In both the compact and the abelian settings, we introduce notions of Zak transforms on $L^2(\Gamma)$ which simplify the analysis of group frames. Meanwhile, we run a parallel program that uses the Zak transform to classify closed subspaces of $L^2(\Gamma)$ which are invariant under left translation by $G$. The two projects give compatible outcomes.
This dissertation contains previously published material.
7
Krasilenko, V. G., O. I. Nikolskyy, A. A. Lazarev, D. V. Nikitovich, В. Г. Красіленко, О. І. Нікольський, О. О. Лазарєв und Д. В. Нікітович. „Simulating optical pattern recognition algorithms for object tracking based on nonlinear models and subtraction of frames“. Thesis, Український державний хіміко-технологічний університет, 2015. http://ir.lib.vntu.edu.ua//handle/123456789/23850.
Der volle Inhalt der QuelleAnnotation:
We have proposed and discussed optical pattern recognition algorithms for object
tracking based on nonlinear equivalence models and subtraction of frames. Experimental results of
suggested algorithms in Mathcad and LabVIEW are shown. Application of equivalent functions and
difference of frames gives good results for recognition and tracking moving objects
8
Shonoda, Emad N. Naseem. „On Ruled Surfaces in three-dimensional Minkowski Space“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-63555.
Der volle Inhalt der QuelleAnnotation:
In a Minkowski three dimensional space, whose metric is based on a strictly convex and centrally symmetric unit ball , we deal with ruled surfaces Φ in the sense of E. Kruppa. This means that we have to look for Minkowski analogues of the classical differential invariants of ruled surfaces in a Euclidean space. Here, at first – after an introduction to concepts of a Minkowski space, like semi-orthogonalities and a semi-inner-product based on the so-called cosine-Minkowski function - we construct an orthogonal 3D moving frame using Birkhoff’s left-orthogonality. This moving frame is canonically connected to ruled surfaces: beginning with the generator direction and the asymptotic plane of this generator g we complete this flag to a frame using the left-orthogonality defined by ; ( is described either by its supporting function or a parameter representation). The plane left-orthogonal to the asymptotic plane through generator g(t) is called Minkowski central plane and touches Φ in the striction point s(t) of g(t). Thus the moving frame defines the Minkowski striction curve S of the considered ruled surface Φ similar to the Euclidean case. The coefficients occurring in the Minkowski analogues to Frenet-Serret formulae of the moving frame of Φ in a Minkowski space are called “M-curvatures” and “M-torsions”. Here we essentially make use of the semi-inner product and the sine-Minkowski and cosine-Minkowski functions. Furthermore we define a covariant differentiation in a Minkowski 3-space using a new vector called “deformation vector” and locally measuring the deviation of the Minkowski space from a Euclidean space. With this covariant differentiation it is possible to declare an “M-geodesicc parallelity” and to show that the vector field of the generators of a skew ruled surface Φ is an M-geodesic parallel field along its Minkowski striction curve s. Finally we also define the Pirondini set of ruled surfaces to a given surface Φ. The surfaces of such a set have the M-striction curve and the strip of M-central planes in common
9
Miller, Ryan Michael. „Continuum Modeling of Liquid-Solid Suspensions for Nonviscometric Flows“. Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4864.
Der volle Inhalt der QuelleAnnotation:
A suspension flow model based on the "suspension balance" approach has been developed. This work modifies the model to allow the solution of suspension flows under general flow conditions. This requires the development of a frame-invariant constitutive model for the particle stress which can take into account the spatially-varying local kinematic conditions. The mass and momentum balances for the bulk suspension
and particle phase are solved numerically using a finite volume method. The particle stress is based upon the computed rate of strain and the local kinematic conditions. A nonlocal stress
contribution corrects the continuum approximation of the particle phase for finite particle size effects. Local kinematic conditions are accounted through the local ratio of rotation to extension in the flow field. The coordinates for the stress definition are the local principal axes of the rate of strain field.
The developed model is applied to a range of problems. (i) Axially-developing conduit flows are computed using both the full two-dimensional solution and the more computationally
efficient "marching" method. The model predictions are compared to experimental results for cross-stream particle concentration profiles and axial development lengths. (ii) Model
predictions are compared to experiments for wide-gap circular Couette flow of a concentrated suspension in a shear-thinning liquid. With minor modification, the suspension flow model predicts the major trends and results observed in this flow. (iii) Comparisons are made to experiments for an axisymmetric contraction-expansion. Model predictions for a two-dimensional planar contraction flow test the influence of model formulation. The variation of the magnitude of an isotropic particle normal stress with local kinematic conditions and anisotropy in the
in-plane normal stresses are both explored. The formulation of the particle phase stress is found to have significant effects on the solid fraction and velocity. (iv) Finally, for a rectangular
piston-driven flow and an obstructed channel flow, a "computational suspension dynamics" study explores the effect of particle migration on the bulk flow field, system pressure drop
and particle phase composition.
10
Siminos, Evangelos. „Recurrent spatio-temporal structures in presence of continuous symmetries“. Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28215.
Der volle Inhalt der QuelleAnnotation:
Thesis (M. S.)--Physics, Georgia Institute of Technology, 2009.Committee Chair: Cvitanovic, Predrag; Committee Member: Dieci, Luca; Committee Member: Grigoriev, Roman; Committee Member: Schatz, Michael; Committee Member: Wiesenfeld, Kurt
Bücher zum Thema "Frame Invariance"
1
Wittman, David M. Time Skew. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199658633.003.0006.
Der volle Inhalt der QuelleAnnotation:
This chapter explores one major consequence of the invariance of c: events that are simultaneous in one frame are not necessarily simultaneous in other frames.We will find that the time coordinates of events are just as frame‐dependent as their positions. This is no accident, but a symmetry between space and time. Viewed in a spacetime diagram, a frame change rotates the grid lines marking time just as much as it rotates the grid lines marking position; this preserves c as the same speed in all frames. Along the way, we practice using skewed grids in spacetime diagrams: identifying the time coordinates of events, identifying events that are simultaneous in a given frame, and adding velocities. Although the skewed grids change the time coordinates of events and even their order in time, we show that they do not change causal relationships between events.
2
Steigmann, David J. Finite Elasticity Theory. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198567783.001.0001.
Der volle Inhalt der QuelleAnnotation:
This book is suitable for a first-year graduate course on Non-linear Elasticity Theory. It is aimed at graduate students, post-doctoral fellows and researchers working in Mechanics. Included is a modern treatment of elementary plasticity theory emphasizing the foundational role played by finite elasticity. The book covers fundamental and advanced material that should be mastered before embarking on research. Included are the concepts of frame invariance, material symmetry, kinematic constraints, a development of nonlinear membrane theory, energy minimizers as stable equilibria and various attendant convexity conditions.
3
Wittman, David M. Spacetime Geometry. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199658633.003.0011.
Der volle Inhalt der QuelleAnnotation:
This chapter shows that the counterintuitive aspects of special relativity are due to the geometry of spacetime. We begin by showing, in the familiar context of plane geometry, how a metric equation separates frame‐dependent quantities from invariant ones. The components of a displacement vector depend on the coordinate system you choose, but its magnitude (the distance between two points, which is more physically meaningful) is invariant. Similarly, space and time components of a spacetime displacement are frame‐dependent, but the magnitude (proper time) is invariant and more physically meaningful. In plane geometry displacements in both x and y contribute positively to the distance, but in spacetime geometry the spatial displacement contributes negatively to the proper time. This is the source of counterintuitive aspects of special relativity. We develop spacetime intuition by practicing with a graphic stretching‐triangle representation of spacetime displacement vectors.
4
Deruelle, Nathalie, und Jean-Philippe Uzan. Cartesian coordinates. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786399.003.0001.
Der volle Inhalt der QuelleAnnotation:
This chapter introduces Euclidean geometry, which provides the mathematical framework in which the laws of Newtonian physics are formulated. It first discusses how the concepts of ‘space’ and ‘relative, apparent, and common’ place are represented by a mathematical ensemble of points—the ‘absolute’ space ε3. A Cartesian frame of absolute space is materialized in ‘relative, apparent, and common’ space by a reference frame. Specifically, this reference frame is a solid trihedral—that is, an ensemble of physical objects whose relative distances are invariable in time and for which an orientation of the axes has been chosen. This chapter postulates that if the labeling of the points of ε3 is changed, the distance between two points remains unchanged. It then goes on to explain further the various associated formulas associated with Cartesian coordinates.
5
Lerner, Richard M., Jacqueline V. Lerner, G. John Geldhof, Steinunn Gestsdóttir, Pamela Ebstyne King, Alistair T. R. Sim, Milena Batanova, Jonathan M. Tirrell und Elizabeth Dowling. Studying Positive Youth Development in Different Nations. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190847128.003.0004.
Der volle Inhalt der QuelleAnnotation:
International interest is growing concerning using strength-based models of adolescent development to understand how mutually influential relations between individuals and their key settings may be a basis for positive, healthy development. Bidirectional relations models are linked to relational developmental systems (RDS) metatheory, with a focus on the positive youth development (PYD) model, the most used ininternational PYD-related research and programs. A three-nation, counterfactual, comparative, longitudinal study is described to understand if Compassion International programs enhance thriving of the world’s poorest youth. RDS metatheory ideas point to the need for longitudinal studies using measures reflecting reliability, validity, and invariance across people, time, and place. This research should be framed by the “specificity principle” to identify individual and setting combinations that capitalize on the strengths of youth and place young people on a thriving trajectory.
6
Clelland, Jeanne N. From Frenet to Cartan: The Method of Moving Frames. American Mathematical Society, 2017.
Den vollen Inhalt der Quelle finden
7
Ivey, Thomas A., und Joseph M. Landsberg. Cartan for Beginners: Differential Geometry Via Moving Frames and Exterior Differential Systems. American Mathematical Society, 2016.
Den vollen Inhalt der Quelle findenBuchteile zum Thema "Frame Invariance"
1
Faccioli, Pietro, und Carlos Lourenço. „Meaning and Interpretation of the Frame-Independent Polarization“. In Particle Polarization in High Energy Physics, 121–46. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08876-6_4.
Der volle Inhalt der QuelleAnnotation:
AbstractThis chapter discusses the importance of the invariant polarization observable $$\mathcal{F}$$ (or $$\tilde{\lambda}$$) in certain physics scenarios, where none of the adoptable polarization frames would provide a particularly simple picture in terms of $$\lambda_\vartheta$$, $$\lambda_\varphi$$ and $$\lambda_{\vartheta\varphi}$$. One such case is the production of Drell--Yan dileptons, where the polarization parameters, calculated including perturbative QCD corrections, satisfy the Lam--Tung identity, a frame-independent relation maintaining its seemingly surprising simplicity even when the polar and azimuthal anisotropies have strong dependences on the particle momentum. The notion of invariant polarization allows us to reinterpret this relation in a geometrical way, explaining it as a mere consequence of helicity conservation and rotational invariance.
2
Faugeras, Olivier. „Cartan's moving frame method and its application to the geometry and evolution of curves in the euclidean, affine and projective planes“. In Applications of Invariance in Computer Vision, 9–46. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/3-540-58240-1_2.
Der volle Inhalt der Quelle
3
Janßen, Christian, Cedric Richter und Heike Wehrheim. „Can ChatGPT support software verification?“ In Fundamental Approaches to Software Engineering, 266–79. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-57259-3_13.
Der volle Inhalt der QuelleAnnotation:
AbstractLarge language models have become increasingly effective in software engineering tasks such as code generation, debugging and repair. Language models like ChatGPT can not only generate code, but also explain its inner workings and in particular its correctness. This raises the question whether we can utilize ChatGPT to support formal software verification.In this paper, we take some first steps towards answering this question. More specifically, we investigate whether ChatGPT can generate loop invariants. Loop invariant generation is a core task in software verification, and the generation of valid and useful invariants would likely help formal verifiers. To provide some first evidence on this hypothesis, we ask ChatGPT to annotate 106 C programs with loop invariants. We check validity and usefulness of the generated invariants by passing them to two verifiers, Frama-C and CPAchecker. Our evaluation shows that ChatGPT is able to produce valid and useful invariants allowing Frama-C to verify tasks that it could not solve before. Based on our initial insights, we propose ways of combining ChatGPT (or large language models in general) and software verifiers, and discuss current limitations and open issues.
4
Chapman, Sandra. „A Frame Invariant Electromagnetism“. In Undergraduate Lecture Notes in Physics, 37–57. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-66818-1_3.
Der volle Inhalt der Quelle
5
Christensen, Ole. „Shift-Invariant Systems“. In Frames and Bases, 1–16. Boston: Birkhäuser Boston, 2008. http://dx.doi.org/10.1007/978-0-8176-4678-3_8.
Der volle Inhalt der Quelle
6
Jackson, David M., und Iain Moffatt. „Vassiliev Invariants of Framed Knots“. In CMS Books in Mathematics, 211–17. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05213-3_12.
Der volle Inhalt der Quelle
7
Faccioli, Pietro, und Carlos Lourenço. „A Frame-Independent Study of the Angular Distribution“. In Particle Polarization in High Energy Physics, 85–120. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08876-6_3.
Der volle Inhalt der QuelleAnnotation:
AbstractThis chapter introduces general frame-independent relations between the observable anisotropy parameters. Some of these relations reflect the geometrical properties of the distribution, including inequalities that delimit the allowed phase space of the anisotropy parameters, and the representation of the distribution in a “canonical” form. The most interesting relation defines a rotation-invariant parameter expressing the intrinsic nature of the polarization, independently of the reference frame.
8
Garbervetsky, Diego, Daniel Gorín und Ariel Neisen. „Enforcing Structural Invariants Using Dynamic Frames“. In Tools and Algorithms for the Construction and Analysis of Systems, 65–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19835-9_8.
Der volle Inhalt der Quelle
9
van de Gronde, Jasper J., und Jos B. T. M. Roerdink. „Group-Invariant Frames for Colour Morphology“. In Lecture Notes in Computer Science, 267–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-38294-9_23.
Der volle Inhalt der Quelle
10
Olver, Peter J., und Juha Pohjanpelto. „Pseudo-Groups, Moving Frames, and Differential Invariants“. In Symmetries and Overdetermined Systems of Partial Differential Equations, 127–49. New York, NY: Springer New York, 2008. http://dx.doi.org/10.1007/978-0-387-73831-4_7.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "Frame Invariance"
1
Cleghorn, Christopher W., und Andries P. Engelbrecht. „Firefly optimization: A study on frame invariance“. In 2017 IEEE Symposium Series on Computational Intelligence (SSCI). IEEE, 2017. http://dx.doi.org/10.1109/ssci.2017.8285251.
Der volle Inhalt der Quelle
2
Gallerano, F., und G. Cannata. „Form invariance and frame indifference of closure relations in LES“. In Turbulence, Heat and Mass Transfer 6. Proceedings of the Sixth International Symposium On Turbulence, Heat and Mass Transfer. Connecticut: Begellhouse, 2009. http://dx.doi.org/10.1615/ichmt.2009.turbulheatmasstransf.1850.
Der volle Inhalt der Quelle
3
Sasaki, Tomoyuki, und Hidehiro Nakano. „Analysis of Reference Frame Invariance for Piecewise-Linear Particle Swarm Optimizer“. In 2018 IEEE International Conference on Systems, Man, and Cybernetics (SMC). IEEE, 2018. http://dx.doi.org/10.1109/smc.2018.00209.
Der volle Inhalt der Quelle
4
Kalivarapu, Vijay, und Eliot Winer. „Diversity and Frame Invariance Characteristics in PSO With and Without Digital Pheromones“. In 51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
18th AIAA/ASME/AHS Adaptive Structures Conference
12th. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2010. http://dx.doi.org/10.2514/6.2010-3080.
5
Koike, Yuji, Koichi Kanazawa, Andreas Metz, Daniel Pitonyak und Marc Schlegel. „Lorentz invariance relations for twist-3 functions and frame-independence of twist-3 cross sections“. In XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.265.0220.
Der volle Inhalt der Quelle
6
Newman, J. Daniel, und R. C. VanVranken. „Shift-invariant imaging using the bispectrum“. In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.wl3.
Der volle Inhalt der QuelleAnnotation:
We describe the results of a new algorithm for processing a series of noise degraded and randomly shifting digital images using the bispectrum. The algorithm is shown to yield a reconstructed signal-to-noise ratio (SNR) improvement which is nearly equal to perfect frame stacking using no prior knowledge whatsoever. The technique is quite robust and has wide ranging applications for situations in which imaging platform stabilization and noise are problematic The algorithm is very efficient and can completely process 128 250 × 128 format image frames in less than ten minutes on a VAX workstation. This is significantly faster than other algorithms we are currently aware of. Comparisons of the bispectrum algorithm with perfect frame registration and an adaptive matched filter algorithm are given for a wide range of simulated data sets. The data sets include both shot noise limited simulations and background noise limited simulations. The results indicate that the technique is more robust than second order matched filter methods due to the inherent shift invariance of the bispectrum. A description of the algorithm is given. It is quite different from other image reconstruction algorithms we are aware of and holds out the possibility of real time digital image processing using only two or three transputer array boards.
7
Cao, Jianfen. „Temporal structure in bisyllabic word frame: an evidence for relational invariance and variability from standard Chinese“. In 2nd International Conference on Spoken Language Processing (ICSLP 1992). ISCA: ISCA, 1992. http://dx.doi.org/10.21437/icslp.1992-355.
Der volle Inhalt der Quelle
8
Draayer, Bret F., Gary W. Carhart, Thomas R. Walsh und Michael K. Giles. „Postprocessing of correlation outputs to improve optical recognition system performance“. In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.thl4.
Der volle Inhalt der QuelleAnnotation:
Optical correlators employing magnetooptic spatial light modulators (MOSLMs) can process binary phase-only filter (BPOF) responses at kilohertz frame rates,1 making real-time recognition possible. However, aspect invariant recognition is difficult since simple BPOFs are highly sensitive to geometric distortions. Aspect invariant composite BPOFs have been developed; unfortunately, filters that achieve aspect invariance over wide distortion ranges produce reduced correlation peak values, rendering simple threshold decision rules ineffective. A statistical correlation plane filter (CPF) based on analysis of variance has been shown to improve recognition system performance.2 This paper examines a multiclass quadratic CPF based on a Bayes likelihood ratio test. The quadratic CPF allows the correlation system to be calibrated by repeatedly analyzing correlation peaks for all object–filter combinations. This off-line calibration process yields a vector of expected correlation peak values and an associated covariance matrix for each unique object with each filter in the filter bank. Once gathered, these data are used on-line to calculate the Mahalanobis distance between an observation vector of peak values obtained with an unknown object and each mean vector. Recognition based on the shortest Mahalanobis distance delivers robust performance, even when composite BPOFs are used in the optical correlator.
9
Kast, B. A., F. M. Dickey und M. L. Yee. „Gray scale correlation with a real-time AO correlator: experimental results“. In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.ws1.
Der volle Inhalt der QuelleAnnotation:
Real-time correlation in the spatial domain has been demonstrated previously by using an acousto-optical (AO) correlator. This acousto-optic system performs correlations at high frame rates, which permits the implementation of real-time pattern recognition algorithms that use multiple templates. Previous work has been done with edge-enhanced templates and images, by using binary rather than full gray-scale pixels. The present work shows the ability of the AO correlator to process gray-scale imagery for the purpose of implementing the classical matched filter. Since intensity invariance is an issue with gray-scale imagery, normalized correlation is implemented on the AO correlator. Experimental results obtained by using real gray-scale imagery are presented.
10
Chirikjian, Gregory S. „Partial Bi-Invariance of SE(3) Metrics“. In ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-34276.
Der volle Inhalt der QuelleAnnotation:
In a flurry of articles in the mid to late 1990s, various metrics for the group of rigid-body motions, SE(3), were introduced for measuring distance between any two reference frames or rigid-body motions. During this time it was shown that one can choose a smooth distance function that is invariant under either all left shifts or all right shifts, but not both. For example, if one defines the distance between two reference frames to be an appropriately weighted Frobenius norm of the difference of the corresponding homogeneous transformation matrices, this will be invariant under left shifts by arbitrary rigid-body motions. However, this is not the full picture — other invariance properties exist. Though the Frobenius norm is not invariant under right shifts by arbitrary rigid-body motions, for an appropriate weighting it is invariant under right shifts by pure rotations. This is also true for metrics based on the Lie-theoretic logarithm. This paper goes further to investigate the full invariance properties of distance functions on SE(3), clarifying the full subsets of motions under which both left and right invariance is possible.
Berichte der Organisationen zum Thema "Frame Invariance"
1
Ron, Amos, und Zuowei Shen. Frames and Stable Bases for Shift-Invariant Subspaces of L2(IRd). Fort Belvoir, VA: Defense Technical Information Center, Februar 1994. http://dx.doi.org/10.21236/ada276470.
Der volle Inhalt der Quelle
2
Thunø, Mette, und Jan Ifversen. Global Leadership Teams and Cultural Diversity: Exploring how perceptions of culture influence the dynamics of global teams. Aarhus University, Oktober 2018. http://dx.doi.org/10.7146/aul.273.
Der volle Inhalt der QuelleAnnotation:
In the 21st century, business engagements are becoming increasingly global, and global teams are now an established form of organising work in multinational organisations. As a result, managing cultural diver-sity within a global team has become an essential part of ensuring motivation, creativity, innovation and efficiency in today’s business world.Global teams are typically composed of a diversity of experiences, frames of references, competencies, information and, not least, cultural backgrounds. As such, they hold a unique potential for delivering high performance in terms of innovative and creative approaches to global management tasks; however, in-stead of focusing on the potentials of cultural diversity, practitioners and studies of global teams tend to approach cultural diversity as a barrier to team success. This study explores some of the barriers that cultural diversity poses but also discusses its potential to leverage high performance in a global context.Our study highlights the importance of how team leaders and team members perceive ‘culture’ as both a concept and a social practice. We take issue with a notion of culture as a relatively fixed and homogeneous set of values, norms and attitudes shared by people of national communities; it is such a notion of culture that tends to underlie understandings that highlight the irreconcilability of cultural differences.Applying a more dynamic and context-dependent approach to culture as a meaning system that people negotiate and use to interpret the world, this study explores how global leadership teams can best reap the benefits of cultural diversity in relation to specific challenging areas of intercultural team work, such as leadership style, decision making, relationship building, strategy process, and communication styles. Based on a close textual interpretation of 31 semi-structured interviews with members of global leader-ship teams in eight Danish-owned global companies, our study identified different discourses and per-ceptions of culture and cultural diversity. For leaders of the global leadership teams (Danish/European) and other European team members, three understandings of cultural diversity in their global teams were prominent:1)Cultural diversity was not an issue2)Cultural diversity was acknowledged as mainly a liability. Diversities were expressed through adifference in national cultures and could typically be subsumed under a relatively fixed numberof invariable and distinct characteristics.3)Cultural diversity was an asset and expressions of culture had to be observed in the situationand could not simply be derived from prior understandings of cultural differences.A clear result of our study was that those leaders of global teams who drew on discourses of the Asian ‘Other’ adherred to the first two understandings of cultural diversity and preferred leadership styles that were either patriarchal or self-defined as ‘Scandinavian’. Whereas those leaders who drew on discourses of culture as dynamic and negotiated social practices adhered to the third understanding of cultural di-versity and preferred a differentiated and analytical approach to leading their teams.We also focused on the perceptions of team members with a background in the country in which the global teams were co-located. These ‘local’ team members expressed a nuanced and multifaceted perspective on their own cultural background, the national culture of the company, and their own position within the team, which enabled them to easily navigate between essentialist perceptions of culture while maintain-ing a critical stance on the existing cultural hegemonies. They recognised the value of their local knowledge and language proficiency, but, for those local members in teams with a negative or essentialist view of cultural diversity, it was difficult to obtain recognition of their cultural styles and specific, non-local competences. 3Our study suggeststhat the way global team members perceive culture, based on dominant societal dis-courses of culture, significantly affects the understandings of roles and positions in global leadership teams. We found that discourses on culture were used to explain differences and similarities between team members, which profoundly affected the social practicesand dynamics of the global team. We con-clude that only global teams with team leaders who are highly aware of the multiple perspectives at play in different contexts within the team hold the capacity to be alert to cultural diversity and to demonstrate agility in leveraging differences and similarities into inclusive and dynamic team practices.