In this paper, we present a novel and simple Yee Finite-Difference Time-Domain (FDTD) scheme to solve numerically the nonlinear second-order thermoviscous Navier–Stokes and the Continuity equations. ...In their original form, these equations cannot be discretized by using the Yee’s mesh, at least, easily. As it is known, the use of the Yee’s mesh is recommended because it is optimized in order to obtain higher computational performance and remains at the core of many current acoustic FDTD softwares. In order to use the Yee’s mesh, we propose to rewrite the aforementioned equations in a novel form. To achieve this, we will use the substitution corollary. This procedure is novel in the literature. Although the scheme can be extended to more than one dimension, in this paper, we will focus only on the one-dimensional solution because it can be validated with two analytical solutions to the Burgers equation: the Mendousse mono-frequency solution and the Lardner bi-frequency solution. Numerical solutions are excellently consistent with the analytical solution, which demonstrates the effectiveness of our formulation.
•A novel FDTD scheme to solve the nonlinearsecond-order thermoviscous hydrodynamic model.•Use substitution corollary to rewrite the hydrodynamic equations.•The numerical results obtained show good agreement with the analytical solutions.•The scheme is competitive for its simplicity, accuracy and speed.
Hyperbolic complex numbers are used in the description of hyperbolic spaces. One of the well-known examples of such spaces is the Minkowski space, which plays a leading role in the problems of the ...special theory of relativity and electrodynamics. However, such numbers are not very common in different programming languages. Of interest is the implementation of hyperbolic complex in scientific programming languages, in particular, in the Julia language. The Julia language is based on the concept of multiple dispatch. This concept is an extension of the concept of polymorphism for object-oriented programming languages. To implement hyperbolic complex numbers, the multiple dispatching approach of the Julia language was used. The result is a library that implements hyperbolic numbers. Based on the results of the study, we can conclude that the concept of multiple dispatching in scientific programming languages is convenient and natural.
Non-negative matrix tri-factorization (NMTF) is a popular technique for learning low-dimensional feature representation of relational data. Currently, NMTF learns a representation of a dataset ...through an optimization procedure that typically uses multiplicative update rules. This procedure has had limited success, and its failure cases have not been well understood. We here perform an empirical study involving six large datasets comparing multiplicative update rules with three alternative optimization methods, including alternating least squares, projected gradients, and coordinate descent. We find that methods based on projected gradients and coordinate descent converge up to twenty-four times faster than multiplicative update rules. Furthermore, alternating least squares method can quickly train NMTF models on sparse datasets but often fails on dense datasets. Coordinate descent-based NMTF converges up to sixteen times faster compared to well-established methods.
Modifications to the data representation of an abstract data type (ADT) can require significant semantic refactoring of the code. Motivated by this observation, this paper presents a new method to ...automate semantic code refactoring tasks. Our method takes as input the original ADT implementation, a new data representation, and a so-called relational representation invariant (relating the old and new data representations), and automatically generates a new ADT implementation that is semantically equivalent to the original version. Our method is based on counterexample-guided inductive synthesis (CEGIS) but leverages three key ideas that allow it to handle real-world refactoring tasks. First, our approach reduces the underlying relational synthesis problem to a set of (simpler) programming-by-example problems, one for each method in the ADT. Second, it leverages symbolic reasoning techniques, based on logical abduction, to deduce code snippets that should occur in the refactored version. Finally, it utilizes a notion of partial equivalence to make inductive synthesis much more effective in this setting. We have implemented the proposed approach in a new tool called Revamp for automatically refactoring Java classes and evaluated it on 30 Java class mined from Github. Our evaluation shows that Revamp can correctly refactor the entire ADT in 97% of the cases and that it can successfully re-implement 144 out of the 146 methods that require modifications.
Power analysis attacks allow the extraction of secret information from smart cards. Smart cards are used in many applications including banking, mobile communications, pay TV, and electronic ...signatures. In all these applications, the security of the smart cards is of crucial importance. Power Analysis Attacks: Revealing the Secrets of Smart Cardsis the first comprehensive treatment of power analysis attacks and countermeasures. Based on the principle that the only way to defend against power analysis attacks is to understand them, this book explains how power analysis attacks work. Using many examples, it discusses simple and differential power analysis as well as advanced techniques like template attacks. Furthermore, the authors provide an extensive discussion of countermeasures like shuffling, masking, and DPA-resistant logic styles. By analyzing the pros and cons of the different countermeasures, this volume allows practitioners to decide how to protect smart cards.
Dieses Open Buch schlägt eine Brücke zwischen Theorie und Praxis für das produzierende Gewerbe im Zeitalter der Digitalisierung, der Industrie 4.0 und der Künstlichen Intelligenz. Es ist das Resultat ...eines vierjährigen Forschungsprojekts, das unter der Leitung des Instituts für Produktionssysteme der Technischen Universität Dortmund und der RapidMiner GmbH in Zusammenarbeit mit zwölf weiteren Partnern durchgeführt wurde. Das Hauptziel des Projekts war die Entwicklung einer Datenanalyse-Plattform zur Förderung einer effektiven und kompetenzorientierten Zusammenarbeit in dynamischen Wertschöpfungsnetzwerken. Die zwanzig Beiträge in diesem Sammelband liefern umfassende Einblicke in die Forschungsergebnisse und schildern die gemeinsamen Erfahrungen der Partner aus produzierenden Unternehmen, Software- und Hardware-Anbietern sowie Forschungseinrichtungen. Im Fokus steht die Entwicklung von Lösungen, die in einem modularen Referenzbaukasten zusammengefasst sind. Dieser Baukasten unterstützt industrielle Datenanalysen und deren Integration in betriebliche Abläufe. Er fördert darüber hinaus eine kompetenzorientierte Zusammenarbeit und ermöglicht somit die Initiierung neuer Geschäftsmodelle und Kollaborationen. Das Buch richtet sich an Praktiker:innen aus der Industrie ebenso wie an Wissenschaftler:innen. Es liefert Impulse und bietet Hilfestellungen, um den Herausforderungen der digitalen Transformation zu begegnen und die Zukunft der industriellen Datenanalyse erfolgreich zu gestalten.
"This book provides a comprehensive reference for the many different types and methods of compression. Included are a detailed and helpful taxonomy, analysis of most common methods, and discussions ...on the use and comparative benefits of methods and description of ""how to"" use them. Detailed descriptions and explanations of the most well-known and frequently used compression methods are covered in a self-contained fashion, with an accessible style and technical level for specialists and nonspecialists. This 4th edition of this successful volume contains significant additional material as there has been tremendous progress in this field, especially in audio compression such as FLAC, AAC, WavPack, ALS and Dolby AC3, which are all covered. Additional key features include: RAR, Tunstall code, Differential and Hyperspectral Compression, LZMA, H.264, 3D data sets, PDF. This book provides an invaluable reference and guide for all researchers and practitioners needing a comprehensive compilation for a broad range of compression methods."
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