The Joint UK Land Environment Simulator (JULES), model description ��� part 1: energy and water fluxes

This manuscript describes the energy and water components of a new community land surface model called the Joint UK Land Environment Simulator (JULES). This is developed from the Met Office Surface Exchange Scheme (MOSES). It can be used as a stand alone land surface model driven by observed forcing data, or coupled to an atmospheric global circulation model. The JULES model has been coupled to the Met Office Unified Model (UM) and as such provides a unique opportunity for the research community to contribute their research to improve both world-leading operational weather forecasting and climate change prediction systems. In addition JULES, and its forerunner MOSES, have been the basis for a number of very high-profile papers concerning the land-surface and climate over the last decade. JULES has a modular structure aligned to physical processes, providing the basis for a flexible modelling platform.

JULES-crop: a parametrisation of crops in the Joint UK Land Environment Simulator

Studies of climate change impacts on the terrestrial biosphere have been completed without recognition of the integrated nature of the biosphere. Improved assessment of the impacts of climate change on food and water security requires the development and use of models not only representing each component but also their interactions. To meet this requirement the Joint UK Land Environment Simulator (JULES) land surface model has been modified to include a generic parametrisation of annual crops. The new model, JULES-crop, is described and evaluation at global and site levels for the four globally important crops; wheat, soybean, maize and rice. JULES-crop demonstrates skill in simulating the inter-annual variations of yield for maize and soybean at the global and country levels, and for wheat for major spring wheat producing countries. The impact of the new parametrisation, compared to the standard configuration, on the simulation of surface heat fluxes is largely an alteration of the partitioning between latent and sensible heat fluxes during the later part of the growing season. Further evaluation at the site level shows the model captures the seasonality of leaf area index, gross primary production and canopy height better than in the standard JULES. However, this does not lead to an improvement in the simulation of sensible and latent heat fluxes. The performance of JULES-crop from both an Earth system and crop yield model perspective is encouraging. However, more effort is needed to develop the parametrisation of the model for specific applications. Key future model developments identified include the introduction of processes such as irrigation and nitrogen limitation which will enable better representation of the spatial variability in yield.

Uso do network simulator-NS para simula����o de sistemas distribu��dos em cen��rios com defeitos

O desenvolvimento de protocolos distribu��dos �� uma tarefa complexa. Em sistemas tolerantes a falhas, a elabora����o de mecanismos para detectar e mascarar defeitos representam grande parte do esfor��o de desenvolvimento. A t��cnica de simula����o pode auxiliar significativamente nessa tarefa. Entretanto, existe uma car��ncia de ferramentas de simula����o para investiga����o de protocolos distribu��dos em cen��rios com defeitos, particularmente com suporte a experimentos em configura����es ���t��picas��� da Internet. O objetivo deste trabalho �� investigar o uso do simulador de redes NS (Network Simulator) como ambiente para simula����o de sistemas distribu��dos, particularmente em cen��rios sujeitos �� ocorr��ncia de defeitos. O NS �� um simulador de redes multi-protocolos, que tem c��digo aberto e pode ser estendido. Embora seja uma ferramenta destinada ao estudo de redes de computadores, o ajuste adequado de par��metros e explora����o de caracter��sticas permitiu utiliz��-lo para simular defeitos em um sistema distribu��do. Para isso, desenvolveu-se dois modelos de sistemas distribu��dos que podem ser implementados no NS, dependendo do protocolo de transporte utilizado: um baseado em TCP e o outro baseado em UDP. Tamb��m, foram estudadas formas de modelar defeitos atrav��s do simulador. Para a simula����o de defeito de colapso em um nodo, foi proposta a implementa����o de um m��todo na classe de cada aplica����o na qual se deseja simular defeitos. Para ilustrar como os modelos de sistemas distribu��dos e de defeitos propostos podem ser utilizados, foram implementados diversos algoritmos distribu��dos em sistemas s��ncronos e ass��ncronos. Algoritmos de elei����o e o protocolo Prim��rio-Backup s��o exemplos dessas implementa����es. A partir desses algoritmos, principalmente do Prim��rio-Backup, no qual a simula����o de defeitos foi realizada, foi poss��vel constatar que o NS pode ser uma ferramenta de grande aux��lio no desenvolvimento de novas t��cnicas de Toler��ncia a Falhas. Portanto, o NS pode ser estendido possibilitando que, com a utiliza����o dos modelos apresentados nesse trabalho, simule-se defeitos em um sistema distribu��do.

Computador - Desktop

Estes itens fazem parte de um conjunto de modelos projetados pela equipe do Laborat��rio de Objetos de Aprendizagem (LOA)/UFSCar para o jogo LabTecA

Teaching real-time with a scheduler simulator

In this paper we describe a scheduler simulator for real-time tasks, RTsim, that can be used as a tool to teach real-time scheduling algorithms. It simulates a variety of preprogrammed scheduling policies for single and multi-processor systems and simple algorithm variants introduced by its user. Using RTsim students can conduct experiments that will allow them to understand the effects of each policy given different load conditions and learn which policy is better for different workloads. We show how to use RTsim as a learning tool and the results achieved with its application on the Real-Time Systems course taught at the B.Sc. on Computer Science at Paulista State University - Unesp - at Rio Preto.

Virtual simulator for mobile robots navigation systems

This paper presents the virtual environment implementation for project simulation and conception of supervision and control systems for mobile robots, that are capable to operate and adapting in different environments and conditions. This virtual system has as purpose to facilitate the development of embedded architecture systems, emphasizing the implementation of tools that allow the simulation of the kinematic conditions, dynamic and control, with real time monitoring of all important system points. For this, an open control architecture is proposal, integrating the two main techniques of robotic control implementation in the hardware level: systems microprocessors and reconfigurable hardware devices. The implemented simulator system is composed of a trajectory generating module, a kinematic and dynamic simulator module and of a analysis module of results and errors. All the kinematic and dynamic results shown during the simulation can be evaluated and visualized in graphs and tables formats, in the results analysis module, allowing an improvement in the system, minimizing the errors with the necessary adjustments optimization. For controller implementation in the embedded system, it uses the rapid prototyping, that is the technology that allows, in set with the virtual simulation environment, the development of a controller project for mobile robots. The validation and tests had been accomplish with nonholonomics mobile robots models with diferencial transmission. �� 2008 IEEE.

Using multiple abstraction levels to speedup an MPSoC virtual platform simulator

Virtual platforms are of paramount importance for design space exploration and their usage in early software development and verification is crucial. In particular, enabling accurate and fast simulation is specially useful, but such features are usually conflicting and tradeoffs have to be made. In this paper we describe how we integrated TLM communication mechanisms into a state-of-the-art, cycle-accurate, MPSoC simulation platform. More specifically, we show how we adapted ArchC fast functional instruction set simulators to the MPARM platform in order to achieve both fast simulation speed and accuracy. Our implementation led to a much faster hybrid platform, reaching speedups of up to 2.9 and 2.1x on average with negligible impact on power estimation accuracy (average 3.26% and 2.25% of standard deviation). �� 2011 IEEE.

Scheduler simulation using iSPD, an iconic-based computer grid simulator

Increased accessibility to high-performance computing resources has created a demand for user support through performance evaluation tools like the iSPD (iconic Simulator for Parallel and Distributed systems), a simulator based on iconic modelling for distributed environments such as computer grids. It was developed to make it easier for general users to create their grid models, including allocation and scheduling algorithms. This paper describes how schedulers are managed by iSPD and how users can easily adopt the scheduling policy that improves the system being simulated. A thorough description of iSPD is given, detailing its scheduler manager. Some comparisons between iSPD and Simgrid simulations, including runs of the simulated environment in a real cluster, are also presented. �� 2012 IEEE.

iSPD: An iconic-based modeling simulator for distributed grids

Simulation of large and complex systems, such as computing grids, is a difficult task. Current simulators, despite providing accurate results, are significantly hard to use. They usually demand a strong knowledge of programming, what is not a standard pattern in today's users of grids and high performance computing. The need for computer expertise prevents these users from simulating how the environment will respond to their applications, what may imply in large loss of efficiency, wasting precious computational resources. In this paper we introduce iSPD, iconic Simulator of Parallel and Distributed Systems, which is a simulator where grid models are produced through an iconic interface. We describe the simulator and its intermediate model languages. Results presented here provide an insight in its easy-of-use and accuracy.

Electrical Power Distribution System modeling with VHDL-AMS for the construction of a Real-Time Digital Simulator using FPGAS devices

This paper presents a distribution feeder simulation using VHDL-AMS, considering the standard IEEE 13 node test feeder admitted as an example. In an electronic spreadsheet all calculations are performed in order to develop the modeling in VHDL-AMS. The simulation results are compared in relation to the results from the well knowing MatLab/Simulink environment, in order to verify the feasibility of the VHDL-AMS modeling for a standard electrical distribution feeder, using the software SystemVision���. This paper aims to present the first major developments for a future Real-Time Digital Simulator applied to Electrical Power Distribution Systems. �� 2012 IEEE.

An open source GPS multipath simulator in Matlab/Octave

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Beneficial effects of fermented vegetal beverages on human gastrointestinal microbial ecosystem in a simulator

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Prebiotic Effect of Fructooligosaccharide in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME (R) Model)

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)