Recent Developments of the Theory of Turbulence

1937 ◽  
Vol 4 (3) ◽  
pp. A105-A108
Author(s):  
Hugh L. Dryden

Abstract A brief account is given of the principal concepts which have been utilized in the formulation of theories of the turbulent motion of fluids prior to 1935 and the new approach originated by G. I. Taylor in that year. A bibliography of 31 papers is included.

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. SM77-SM93 ◽  
Author(s):  
Tim T. Lin ◽  
Felix J. Herrmann

An explicit algorithm for the extrapolation of one-way wavefields is proposed that combines recent developments in information theory and theoretical signal processing with the physics of wave propagation. Because of excessive memory requirements, explicit formulations for wave propagation have proven to be a challenge in 3D. By using ideas from compressed sensing, we are able to formulate the (inverse) wavefield extrapolation problem on small subsets of the data volume, thereby reducing the size of the operators. Compressed sensing entails a new paradigm for signal recovery that provides conditions under which signals can be recovered from incomplete samplings by nonlinear recovery methods that promote sparsity of the to-be-recovered signal. According to this theory, signals can be successfully recovered when the measurement basis is incoherent with the representa-tion in which the wavefield is sparse. In this new approach, the eigenfunctions of the Helmholtz operator are recognized as a basis that is incoherent with curvelets that are known to compress seismic wavefields. By casting the wavefield extrapolation problem in this framework, wavefields can be successfully extrapolated in the modal domain, despite evanescent wave modes. The degree to which the wavefield can be recovered depends on the number of missing (evanescent) wavemodes and on the complexity of the wavefield. A proof of principle for the compressed sensing method is given for inverse wavefield extrapolation in 2D, together with a pathway to 3D during which the multiscale and multiangular properties of curvelets, in relation to the Helmholz operator, are exploited. The results show that our method is stable, has reduced dip limitations, and handles evanescent waves in inverse extrapolation.


2012 ◽  
pp. 277
Author(s):  
Pedro A. Fuertes-Olivera ◽  
Beatriz Pérez Cabello de Alba

Con el nombre de Inglés para Fines Específicos, mas conocido por el acrónimo inglés ESP, nos referimos a la variedad de la lengua inglesa que se enseña a los estudiantes matriculados en carreras como Económicas, Turismo, Medicina e Ingenierías. Desde sus inicios hasta la fecha hemos asistido a un gran crecimiento en el número de estudiantes y cursos ofertados, que ha obligado a poner en marcha prácticas docentes autónomas, es decir sin la participación de expertos en el campo, y replicativas, es decir prácticas que fueron inicialmente diseñadas para el aprendizaje de las destrezas profesionales, como por ejemplo el uso del estudio de casos procedente de los Masters of Business Administration (MBA). Ambos procesos, unidos al desarrollo del inglés como lingua franca y al interés por el desarrollo de una metodología que favorezca la autonomía de los estudiantes, se han traducido en un desarrollo espectacular de herramientas docentes de Internet. En este marco se sitúa este trabajo que se organiza en tres grandes apartados: (1) una precisión del concepto de ESP y una reinterpretación del mismo; (2) una revisión del concepto de lexicografía y del diccionario pedagógico; (3) una descripción de las posibilidades que ofrecen los diccionarios de Internet para poder leer textos de inglés empresarial/inglés económico. El artículo finaliza resumiendo las principales ideas defendidas en este trabajo.From its inception in the early 1960s, English for Specific Purposes (ESP) has grown to become one of the most prominent areas of EFL teaching. ESP is usually concerned with the teaching of English used in academic studies and/or professional activities, especially the teaching of English related with Business/Economics, Tourism, Medicine, and Engineering. As the number of courses and students has grown considerably the original team teaching methodology is being substituted by a more autonomous approach in which both ESP instructors and students have to acquire knowledge of the basic concepts of the field by themselves, as well as upgrade their discourse competence. This new approach lends support to recent developments in the field of learner’s autonomy, especially those based on Internet (for example, Moodle) that are being promoted in this era of shortages and lack of resources. Within this framework, this article offers a review of the state of art regarding ESP, formulates a reconceptualization of the concept with the aim of making room to two recent developments: the consolidation of English as lingua franca; and the possibilities offered by the Internet for teaching and learning. It also enumerates the main basic requirements of pedagogically-oriented specialised dictionaries and illustrates some of their potentialities for assisting users in a reading situation. The article finishes by summarising the main conclusions drawn.


2004 ◽  
Vol 13 (01) ◽  
pp. 19-28 ◽  
Author(s):  
MATTHIAS BRACK ◽  
CHRISTIAN AMANN ◽  
MIKHAIL PLETYUKHOV ◽  
OLEG ZAITSEV

We summarize recent developments of the semiclassical description of shell effects in finite fermion systems with explicit inclusion of spin degrees of freedom, in particluar in the presence of spin-orbit interactions. We present a new approach that makes use of spin coherent states and a correspondingly enlarged classical phase space. Taking suitable limits, we can recover some of the earlier approaches. Applications to some model systems are presented.


Robotica ◽  
2011 ◽  
Vol 30 (2) ◽  
pp. 185-193 ◽  
Author(s):  
F. García ◽  
F. Jiménez ◽  
J. E. Naranjo ◽  
J. G. Zato ◽  
F. Aparicio ◽  
...  

SUMMARYThe recent developments in applications that have been designed to increase road safety require reliable and trustworthy sensors. Keeping this in mind, the most up-to-date research in the field of automotive technologies has shown that LIDARs are a very reliable sensor family. In this paper, a new approach to road obstacle classification is proposed and tested. Two different LIDAR sensors are compared by focusing on their main characteristics with respect to road applications. The viability of these sensors in real applications has been tested, where the results of this analysis are presented.


1997 ◽  
Vol 06 (03) ◽  
pp. 365-395 ◽  
Author(s):  
Lefteri H. Tsoukalas

Anticipatory systems are systems whose change of state is based on information about present as well as future states. Planning and acting on the basis of anticipations of the future is an omnipresent feature of human control strategies, deeply permeating our daily experience and considered as the hallmark of natural intelligence. Yet, as the eminent mathematical biologist Robert Rosen has pointed out in his book Anticipatory Systems (1985), such control strategies are curiously absent from existing formal approaches to automatic control and decision-making processes. Recent developments in biology, ethology and cognitive sciences, however, as well as advancements in the technology of computer-based predictive models, compel us to reconsider the role of anticipation in intelligent systems and to the extent possible incorporate it in our formal approaches to control. Significant improvements in neural predictive computing when combined with the flexibility of fuzzy systems, supports the development of neurofuzzy anticipatory control architectures that integrate planning and control sequencing functions with feedback control algorithms. A review of the role of anticipation in intelligent systems and a new approach for neurofuzzy anticipatory control using radial basis neural predictive models and fuzzy if/then rules is presented.


2018 ◽  
Vol 5 (2) ◽  
pp. 144-158 ◽  
Author(s):  
Yuri Kivshar

Abstract Most optical metamaterials fabricated and studied to date employ metallic components resulting in significant losses, heat and overall low efficiencies. A new era of metamaterial physics is associated with all-dielectric meta-optics, which employs electric and magnetic Mie resonances of subwavelength particles with high refractive index for an optically induced magnetic response, thus underpinning a new approach to design and fabricate functional and practical metadevices. Here we review the recent developments in meta-optics and subwavelength dielectric photonics and demonstrate that the Mie resonances can play a crucial role in the realization of the unique functionalities of meta-atoms, also driving novel effects in the fields of metamaterials and nanophotonics. We discuss the recent research frontiers in all-dielectric meta-optics and uncover how Mie resonances can be employed for a flexible control of light with full phase and amplitude engineering, including unidirectional metadevices, highly transparent metasurfaces, non-linear nanophotonics and topological photonics.


2005 ◽  
Vol 33 (66_suppl) ◽  
pp. 53-60 ◽  
Author(s):  
Isaac Prilleltensky

The promotion of personal, relational, and collective well-being has evolved markedly in the last three decades. However positive and needed, recent developments in health promotion require further conceptual clarification and synergistic applications. To assist with conceptual clarification, this article proposes to distinguish among sites, signs, sources, and strategies of well-being. With respect to applications, progress is discussed along four domains: temporal, ecological, participation, and capabilities. The temporal domain refers to the timing of interventions and entails a continuum from reactive to proactive strategies. The ecological domain pertains to the site of interventions, ranging from person-centered to community-centered. The participation domain refers to voice and choice of citizens and consumers in delivery of services and access to resources. At one end of this continuum there is empowerment, while at the opposite end we see disempowerment and detachment. Finally, the capabilities domain refers to the concentration on either strengths or deficits. This article argues that a singular focus on strength, prevention, empowerment, or community conditions is insufficient. It presents a framework for the conceptual integration of these four approaches, while illustrating the benefits of their synergy and the risks of their fragmentation. It is high time for a paradigm shift in health and human services, and this article argues that only a new approach that focuses on strengths, prevention, empowerment, and community conditions can make considerable progress towards the achievement of well-being for all.


Author(s):  
José M. Amigó ◽  
Karsten Keller ◽  
Valentina A. Unakafova

Ordinal symbolic analysis opens an interesting and powerful perspective on time-series analysis. Here, we review this relatively new approach and highlight its relation to symbolic dynamics and representations. Our exposition reaches from the general ideas up to recent developments, with special emphasis on its applications to biomedical recordings. The latter will be illustrated with epilepsy data.


2019 ◽  
Vol 21 (4) ◽  
pp. 309-317
Author(s):  
Julie Foulon

As a consequence of increased pressure on environment in Europe and beyond, the extent and variety of forms of environmental damage has broadened widely over the last decades. One key way to tackle this problem is, evidently, to ensure that damage that arise is properly repaired. Whilst provisions to secure environmental liability have been implemented in the EU context through the Environmental Liability Directive, the effectiveness of this Directive is still limited. In France, in order to surpass current impasses, the 2016 Biodiversity Law was recently enacted (adopted on August 8th, 2016), which creates a specific regime in French civil law for remedying ecological damage (defined as damage caused to nature itself). Three years after the introduction of France’s new approach to ecological damage, the present article reflects on the legal innovations and challenges of the reform, and explains how the new regime proceeds to remedy ecological damage. A key challenge here, as will be discussed, is that nature as such has not been recognised as having legal personality under the French legal system, which has traditionally been a key hurdle for securing compensation for environmental loss in the first place under tort law.


2016 ◽  
Vol 9 (5) ◽  
pp. 1119 ◽  
Author(s):  
Jaione Ganzarain ◽  
Nekane Errasti

Purpose: To address the challenges regarding the concept of Industry 4.0 and the diversification methodology and based on the strategic guidance towards Industry 4.0, we propose a process model as a guiding framework for Industry 4.0 collaborative diversification vision, strategy and action building. In this paper we suggest a stage process model to guide and train companies to identify new opportunities for diversification within Industry 4.0. Systematically carrying out the stages will take a company to their individual specific vision and collaborative vision between different companies in the Industry 4.0 scenario.Design/methodology/approach: This new collaborative diversification methodology involves industry within the pilot program; from the diversification and capacity assessment analysis of the company`s profile, skills and technologies that dominates, to identify the diversification opportunity map and its business modeling within the Industry 4.0 paradigm.Findings: The application of maturity models to the Industry 4.0 may help organizations to integrate this methodology into their culture. Results show a real need for guided support in developing a company-specific Industry 4.0 vision and specific project planning.Originality/value: Industry 4.0 promotes a vision where recent developments in information technology are expected to enable entirely new forms of cooperative engineering and manufacturing. The vision of industry 4.0 describes a whole new approach to business operations, and especially the production industries. To address the challenges regarding the concept of Industry 4.0 and the diversification methodology discussed above, and based on the strategic guidance towards Industry 4.0, we propose a unique process model as a guiding framework for Industry 4.0 collaborative diversification vision, strategy and action building.


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