695 research outputs found
Virtual Environments for multiphysics code validation on Computing Grids
We advocate in this paper the use of grid-based infrastructures that are
designed for seamless approaches to the numerical expert users, i.e., the
multiphysics applications designers. It relies on sophisticated computing
environments based on computing grids, connecting heterogeneous computing
resources: mainframes, PC-clusters and workstations running multiphysics codes
and utility software, e.g., visualization tools. The approach is based on
concepts defined by the HEAVEN* consortium. HEAVEN is a European scientific
consortium including industrial partners from the aerospace, telecommunication
and software industries, as well as academic research institutes. Currently,
the HEAVEN consortium works on a project that aims to create advanced services
platforms. It is intended to enable "virtual private grids" supporting various
environments for users manipulating a suitable high-level interface. This will
become the basis for future generalized services allowing the integration of
various services without the need to deploy specific grid infrastructures
Research and Education in Computational Science and Engineering
Over the past two decades the field of computational science and engineering
(CSE) has penetrated both basic and applied research in academia, industry, and
laboratories to advance discovery, optimize systems, support decision-makers,
and educate the scientific and engineering workforce. Informed by centuries of
theory and experiment, CSE performs computational experiments to answer
questions that neither theory nor experiment alone is equipped to answer. CSE
provides scientists and engineers of all persuasions with algorithmic
inventions and software systems that transcend disciplines and scales. Carried
on a wave of digital technology, CSE brings the power of parallelism to bear on
troves of data. Mathematics-based advanced computing has become a prevalent
means of discovery and innovation in essentially all areas of science,
engineering, technology, and society; and the CSE community is at the core of
this transformation. However, a combination of disruptive
developments---including the architectural complexity of extreme-scale
computing, the data revolution that engulfs the planet, and the specialization
required to follow the applications to new frontiers---is redefining the scope
and reach of the CSE endeavor. This report describes the rapid expansion of CSE
and the challenges to sustaining its bold advances. The report also presents
strategies and directions for CSE research and education for the next decade.Comment: Major revision, to appear in SIAM Revie
Distributed Workflows for Multi-physics Applications in Aeronautics
International audienceThe industry requires innovative technologies to support the numeric design and simulation of manufactured products in order to reduce time to market delays and improve the performance of the products and the efficiency of the industries in the global competitive market. Innovation also requires advanced tools to support the design of new products. For example, remote teams are working collaboratively on the preliminary design of future aircraft that will be “safer, quieter, cleaner”, and environmentally friendly by 2020. The automotive industry has similar concerns. The telecom industries (e.g., mobile phones design) and nuclear power plant design face large-scale multi-physics simulation and optimization challenges. This paper suggests that distributed workflows running on computational grids are adequate to support their application needs
Collaborative Multidisciplinary Design in Virtual Environments
International audienceThe application designers can usually define their own “virtual environments” by selecting the appropriate computing resources required, or reuse and compose existing environments. The approach is generic by allowing various application domains to benefit from potential hardware and software resources located on remote computing facilities in a simple and intuitive way. The computing resources are defined by services made available as sets of standardized interfaces performing specific tasks: application workflow, input data streams, output visualization tools, monitoring facilities, etc. Services can be composed and hierarchically defined. Transparent access to heterogeneous hardware and software operating systems is guaranteed. An aeroelasticity example in airliner design is given
A Review of Platforms for the Development of Agent Systems
Agent-based computing is an active field of research with the goal of
building autonomous software of hardware entities. This task is often
facilitated by the use of dedicated, specialized frameworks. For almost thirty
years, many such agent platforms have been developed. Meanwhile, some of them
have been abandoned, others continue their development and new platforms are
released. This paper presents a up-to-date review of the existing agent
platforms and also a historical perspective of this domain. It aims to serve as
a reference point for people interested in developing agent systems. This work
details the main characteristics of the included agent platforms, together with
links to specific projects where they have been used. It distinguishes between
the active platforms and those no longer under development or with unclear
status. It also classifies the agent platforms as general purpose ones, free or
commercial, and specialized ones, which can be used for particular types of
applications.Comment: 40 pages, 2 figures, 9 tables, 83 reference
The Astrophysical Multipurpose Software Environment
We present the open source Astrophysical Multi-purpose Software Environment
(AMUSE, www.amusecode.org), a component library for performing astrophysical
simulations involving different physical domains and scales. It couples
existing codes within a Python framework based on a communication layer using
MPI. The interfaces are standardized for each domain and their implementation
based on MPI guarantees that the whole framework is well-suited for distributed
computation. It includes facilities for unit handling and data storage.
Currently it includes codes for gravitational dynamics, stellar evolution,
hydrodynamics and radiative transfer. Within each domain the interfaces to the
codes are as similar as possible. We describe the design and implementation of
AMUSE, as well as the main components and community codes currently supported
and we discuss the code interactions facilitated by the framework.
Additionally, we demonstrate how AMUSE can be used to resolve complex
astrophysical problems by presenting example applications.Comment: 23 pages, 25 figures, accepted for A&
Multiphysics Simulation and Model-based System Testing of Automotive E-Powertrains
Programa Oficial de Doutoramento en Enxeñaría Naval e Industrial . 5015V01[Abstract]
Model-Based System Testing emerges as a new paradigm for the development
cycle that is currently gaining momentum, especially in the automotive industry.
This novel approach is focused on combining computer simulation and real experimentation
to shift the bulk of problem detection and redesign tasks towards the
early stages of the developments. Along these lines, Model-Based System Testing
is aimed at decreasing the amount of resources invested in these tasks and enabling
the early identification of design flaws and operation problems before a full-vehicle
prototype is available. The use of Model-Based System Testing, however, requires to
implement some critical technologies, three of which will be discussed in this thesis.
The first task addressed in this thesis is the design of a multiplatform framework
to assess the description and resolution of the equations of motion of virtual
models used in simulation. This framework enables the efficiency evaluation of different
modelling and solution methods and implementations. In Model-Based System
Testing contexts virtual models interact with physical components, therefore it is
mandatory to guarantee their real-time capabilities, regardless of the software or
hardware implementations.
Second, estimation techniques based on Kalman Filters are of interest in Model-
Based System Testing applications to evaluate parameters, inputs or states of a
virtual model of a given system. These procedures can be combined with the use
of Digital Twins, virtual counterparts of real systems, with which they exchange
information in a two-way communication. The available measurements from the
sensors located at a physical system can be fused with the results obtained from
the simulation of the virtual model. Thus, this avenue improves the knowledge of
the magnitudes that cannot be measured directly by these sensors. In turn, the
outcomes obtained from the simulation of the virtual model could serve to make
decisions and apply corrective actions onto the physical system.
Third, co-simulation techniques are necessary when a system is split into several
subsystems that are coordinated through the exchange of a reduced set of variables
at discrete points in time. This is the case with a majority of Model-Based System
Testing applications, in which physical and virtual components are coupled through
a discrete-time communication gateway. The resulting cyber-physical applications
are essentially an example of real-time co-simulation, in which all the subsystems
need to achieve real-time performance. Due to the presence of physical components,
which cannot iterate over their integration steps, explicit schemes are often
mandatory. These, however, introduce errors associated with the inherent delays of
a discrete communication interface. These errors can render co-simulation results
inaccurate and even unstable unless they are eliminated. This thesis will address
this correction by means of an energy-based procedure that considers the power
exchange between subsystems.
This research work concludes with an example of a cyber-physical application,
in which real components are interfaced to a virtual environment, which requires
the application of all the MBST technologies addressed in this thesis.[Resumen]
Los ensayos de sistemas basados en modelos emergen como un nuevo paradigma
de desarrollo que actualmente está ganando popularidad, especialmente en la industria
automotriz. Este nuevo enfoque se centra en combinar la simulación por
ordenador con la experimentación para desplazar la mayor parte de la detección
de problemas y rediseños hacia las fases tempranas del desarrollo. De esta forma,
los ensayos de sistemas basados en modelos se centran en disminuir la cantidad de
recursos invertidos en estas tareas y habilitar la identificación temprana de errores
de diseño y problemas durante la operación, incluso antes de que los prototipos del
vehículo completo estén disponibles. Sin embargo, el uso de esta estrategia requiere
implementar algunas tecnologías críticas, tres de las cuales serán tratadas en esta
tesis.
La primera tarea abordada en esta tesis es el diseño de un entorno multiplataforma
para evaluar la descripción y resolución de las ecuaciones de la dinámica
de los modelos virtuales usados en las simulaciones. Este marco permite una evaluación
eficiente de las diferentes formas de modelar los sistemas y de los métodos
de resolución e implementación. En este contexto de ensayos basados en modelos,
los sistemas virtuales interactúan con los componentes de los sistemas físicos,
por lo tanto es necesario garantizar sus capacidades de ejecución en tiempo real,
independientemente de la plataforma de software y hardware utilizada.
En segundo lugar, las técnicas de estimación basadas en filtros de Kalman son de
gran interés en las aplicaciones que usan ensayos basados en modelos para evaluar
los parámetros, entradas o estados de los modelos virtuales de un sistema dado. Estos
procedimientos se pueden combinar con el uso de gemelos digitales, homólogos
virtuales de un sistema físico, con el cual mantienen un flujo bidireccional de intercambio
de información. Las medidas disponibles procedentes de los sensores
instalados en un sistema físico se pueden combinar con los resultados obtenidos de
la simulación del sistema virtual. De este modo, este enfoque mejora el conocimiento
de las magnitudes que no pueden ser medidas directamente por los sensores. A su
vez, los resultados de la simulación de los sistemas de los modelos virtuales pueden
servir para tomar decisiones y aplicar medidas correctivas al sistema real.
En tercer lugar, las técnicas de co-simulación son necesarias cuando un sistema
se divide en varios subsistemas, coordinados a través del intercambio de un reducido
número de variables en momentos puntuales. Este es el caso de la mayor parte de
las aplicaciones que siguen la estrategia de ensayos basados en modelos, en los cuales
los componentes físicos y virtuales se acoplan mediante una comunicación en tiempo
discreto. Como resultado las aplicaciones ciberfísicas son en esencia un ejemplo de
co-simulación en tiempo real, en la que todos los subsistemas necesitan cumplir los
requisitos de ejecución en tiempo real. Debido a la presencia de componentes físicos,
que no pueden reiterar sus pasos de integración, el uso de esquemas explícitos es
frecuentemente necesario. Sin embargo, estos esquemas introducen errores asociados
con los retrasos propios de una interfaz de tiempo discreto. Estos errores pueden
dar lugar a resultados erróneos e incluso inestabilizar la co-simulación, si no son
eliminados. Esta tesis aborda la corrección de la co-simulación a través de métodos
energéticos basados en la potencia intercambiada por los subsistemas. Este trabajo de investigación concluye con un ejemplo de aplicación ciberfísica,
en la que se conectan componentes reales a una simulación por ordenador. Esta
aplicación requiere la aplicación de las tecnologías de ensayos basados en modelos
presentadas a lo largo de esta tesis.[Resumo]
Os ensaios de sistemas baseados en modelos xorden como un novo paradigma
de desenvolvemento que actualmente está gañando popularidade, especialmente na
industria automotriz. Este novo enfoque céntrase en combinar a simulación por
ordenador coa experimentación para desprazar a maior parte da detección de problemas
e redeseños cara as fases iniciais do ciclo de produto. Deste xeito, os ensaios
de sistemas baseados en modelos fundaméntanse en diminuír a cantidade de recursos
investidos nestas tarefas e habilitar a identificación temperá de erros de deseño
e problemas durante a operación, aínda se os prototipos do vehículo completo non
están dispoñibeis. Porén, o uso desta estratexia require implementar algunhas tecnoloxías críicas, tres das cales serán tratadas nesta tese.
A primeira tarefa tratada nesta tese é o deseño dun entorno multiplataforma
para avaliar a descripción e resolución das ecuacións da dinámica dos modelos virtuais
empregados nas simulacións. Este entorno permite unha avaluación eficiente
dos diferentes xeitos de modelar os sistemas e dos métodos de resolución e implementación. Neste contexto de ensaios baseados en modelos, os sistemas virtuais
interactúan cos compoñentes dos sistemas físicos, polo tanto é necesario garantir as
súas capacidades de execución en tempo real, independentemente da plataforma de
hardware e software escollida.
En segundo lugar, as técnicas de estimación baseadas en filtros de Kalman son de
grande interese nas aplicacións que usan ensaios baseados en modelos para avaliar os
seus parámetros, entradas ou estados dos modelos virtuais dun certo sistema. Estes
procedementos pódense combinar co uso de xemelgos dixitais, homólogos virtuais
dun sistema físico, co cal manteñen un fluxo bidireccional de intercambio de información. As medidas dispoñíbeis procedentes dos sensores instalados nun sistema
físico pódense combinar cos resultados obtidos da simulación do sistema virtual.
Deste xeito, este enfoque mellora o coñecemento das magnitudes que non poden ser
medidas directamente polos sensores. Á súa vez, os resultados da simulación dos
sistemas dos modelos virtuais poden servir para tomar decisións e aplicar medidas
correctivas ao sistema real.
En terceiro lugar, as técnicas de co-simulación son necesarias cando un sistema
é dividido en varios subsistemas, coordinados a través do intercambio dun reducido
número de variables en momentos puntuais. Este é o caso da maior parte das
aplicacións que seguen a estratexia de ensaios baseados en modelos, nos cales os
compoñentes físicos e virtuais se acoplan mediante unha comunicación en tempo
discreto. Como resultado as aplicacións ciberfísicas son esencialmente un exemplo
de co-simulación en tempo real, na que tódolos subsistemas necesitan cumprir os
requisitos de execución en tempo real. Debido á presenza de compoñentes físicos, que
non poden reiterar os seus pasos de integración, o uso de esquemas explícitos é polo
xeral necesario. Con todo, estes esquemas introducen erros asociados cos atrasos
derivados dunha interface de tempo discreto. Estes erros poden provocar resultados
incorrectos e incluso inestabilizar a co-simulación, de non seren eliminados. Esta
tese aborda a corrección da co-simulación a través de métodos enerxéticos baseados
na potencia intercambiada polos subsistemas.
Este traballo conclúe cun exemplo de aplicación ciberfísica, na que os compoñentes
reais son conectados a un entorno virtual. Isto require o emprego de tódalas tecnoloxías de ensaios baseadas en modelos presentadas ao longo desta tese
Research and Education in Computational Science and Engineering
This report presents challenges, opportunities, and directions for computational science and engineering (CSE) research and education for the next decade. Over the past two decades the field of CSE has penetrated both basic and applied research in academia, industry, and laboratories to advance discovery, optimize systems, support decision-makers, and educate the scientific and engineering workforce. Informed by centuries of theory and experiment, CSE performs computational experiments to answer questions that neither theory nor experiment alone is equipped to answer. CSE provides scientists and engineers with algorithmic inventions and software systems that transcend disciplines and scales. CSE brings the power of parallelism to bear on troves of data. Mathematics-based advanced computing has become a prevalent means of discovery and innovation in essentially all areas of science, engineering, technology, and society, and the CSE community is at the core of this transformation. However, a combination of disruptive developments---including the architectural complexity of extreme-scale computing, the data revolution and increased attention to data-driven discovery, and the specialization required to follow the applications to new frontiers---is redefining the scope and reach of the CSE endeavor. With these many current and expanding opportunities for the CSE field, there is a growing demand for CSE graduates and a need to expand CSE educational offerings. This need includes CSE programs at both the undergraduate and graduate levels, as well as continuing education and professional development programs, exploiting the synergy between computational science and data science. Yet, as institutions consider new and evolving educational programs, it is essential to consider the broader research challenges and opportunities that provide the context for CSE education and workforce development
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