Distributed simulation of building systems for legacy software reuse

The use of integrated building performance simulation can substantially help in improving a building design with regards to comfort levels and fuel consumption, while reducing emission of greenhouse gasses. However, the traditional tools that are closed for inter-communication, limit the modeler to use of components only available within that particular package. This paper gives an overview of distributed simulation approach that can alleviate above limitation. Each program can represent only a part of a building system that is able to model, exchanging the necessary information during the execution and bridging the gaps between the tools. Several important issues closely connected with its implementation, such as synchronization, are pointed out, and the sensitivity of a model on different coupling strategies is studied. The paper concludes with highlighting the gained flexibility in modeling and simulation of building performance that arises from the distributed approach

Enabling Connectors in Hierarchical Component Models

The continual growth of computing and storage capabilities enables scientific numerical applications to integrate more and more phenomena in their computations at the price of increased complexity. Hierarchical component models appear as an interesting approach to handle such complexity. However defining and implementing efficient interactions between hierarchical components is a difficult task, especially in the case of parallel and distributed applications. Connectors originating from Architecture Description Languages (ADL) offer a promising solution to this problem. There are however some cases where a simple combination of hierarchy and connectors in a single component model forces users to choose between an efficient implementation of components and their black box behavior. This paper describes HLCM, a model with connectors and hierarchy that provides /open connections/ as a mechanism to describe component interface that enhances encapsulation and eases component implementation replacement while supporting efficient interactions. Complex interactions such as data sharing and parallel method calls are successfully supported by HLCM. An implementation, based on model transformation and on CCM, illustrates its feasibility and benefits.La croissance continue des capacités de calcul et de stockage permet aux applications numériques d'intégrer un nombre croissant de phénomènes dans leurs calculs au prix d'une complexité accrue. Les modèles de composants hiérarchiques apparaissent comme une approche intéressante pour gérer cette complexité. Cependant, définir et implémenter des interactions efficaces entre composants hiérarchiques est une tâche difficile, d'autant plus dans le cas d'applications parallèles et distribuées. Les connecteurs issus des langages de description d'architecture (ADL) offrent une solution prometteuse à ce problème. Il y a cependant des cas où une simple combinaison de la hiérarchie et des connecteurs dans un modèle de composants unique oblige l'utilisateur à faire un choix entre des mises en œuvres efficaces pour les composants et leur comportement «boîte noire». Ce papier décrit HLCM, un modèle avec connecteurs et hiérarchie qui fournit le concept de /connexions ouvertes/ pour decrire les interfaces de composants. Ce méchanisme améliore l'encapsulation et facilite le remplacement des mises en œuvre de composant tout en permettant des interactions efficaces. Des interactions complexes telles que le partage de données ou les invocations de méthodes parallèles sont gérées avec succès par HLCM. Une mise en œuvre basée sur une transformation de modèle et sur CCM est utilisée pour illustrer sa faisabilité et ses bénéfices

Numerical Propulsion System Simulation Architecture

The Numerical Propulsion System Simulation (NPSS) is a framework for performing analysis of complex systems. Because the NPSS was developed using the object-oriented paradigm, the resulting architecture is an extensible and flexible framework that is currently being used by a diverse set of participants in government, academia, and the aerospace industry. NPSS is being used by over 15 different institutions to support rockets, hypersonics, power and propulsion, fuel cells, ground based power, and aerospace. Full system-level simulations as well as subsystems may be modeled using NPSS. The NPSS architecture enables the coupling of analyses at various levels of detail, which is called numerical zooming. The middleware used to enable zooming and distributed simulations is the Common Object Request Broker Architecture (CORBA). The NPSS Developer's Kit offers tools for the developer to generate CORBA-based components and wrap codes. The Developer's Kit enables distributed multi-fidelity and multi-discipline simulations, preserves proprietary and legacy codes, and facilitates addition of customized codes. The platforms supported are PC, Linux, HP, Sun, and SGI

Performance evaluation of a distributed integrative architecture for robotics

The eld of robotics employs a vast amount of coupled sub-systems. These need to interact cooperatively and concurrently in order to yield the desired results. Some hybrid algorithms also require intensive cooperative interactions internally. The architecture proposed lends it- self amenable to problem domains that require rigorous calculations that are usually impeded by the capacity of a single machine, and incompatibility issues between software computing elements. Implementations are abstracted away from the physical hardware for ease of de- velopment and competition in simulation leagues. Monolithic developments are complex, and the desire for decoupled architectures arises. Decoupling also lowers the threshold for using distributed and parallel resources. The ability to re-use and re-combine components on de- mand, therefore is essential, while maintaining the necessary degree of interaction. For this reason we propose to build software components on top of a Service Oriented Architecture (SOA) using Web Services. An additional bene t is platform independence regarding both the operating system and the implementation language. The robot soccer platform as well as the associated simulation leagues are the target domain for the development. Furthermore are machine vision and remote process control related portions of the architecture currently in development and testing for industrial environments. We provide numerical data based on the Python frameworks ZSI and SOAPpy undermining the suitability of this approach for the eld of robotics. Response times of signi cantly less than 50 ms even for fully interpreted, dynamic languages provides hard information showing the feasibility of Web Services based SOAs even in time critical robotic applications

Forum Session at the First International Conference on Service Oriented Computing (ICSOC03)

The First International Conference on Service Oriented Computing (ICSOC) was held in Trento, December 15-18, 2003. The focus of the conference ---Service Oriented Computing (SOC)--- is the new emerging paradigm for distributed computing and e-business processing that has evolved from object-oriented and component computing to enable building agile networks of collaborating business applications distributed within and across organizational boundaries. Of the 181 papers submitted to the ICSOC conference, 10 were selected for the forum session which took place on December the 16th, 2003. The papers were chosen based on their technical quality, originality, relevance to SOC and for their nature of being best suited for a poster presentation or a demonstration. This technical report contains the 10 papers presented during the forum session at the ICSOC conference. In particular, the last two papers in the report ere submitted as industrial papers

Coupling SPH with a 1-D Boussinesq-type wave model

International audienceThe high computational cost of SPH remains problematic in dealing with wave propagation, especially when the domains considered are large. In order to overcome this difficulty, we propose to couple 2-D SPH with a 1-D Finite Difference Boussinesq-type model. The latter deals with wave propagations for most of the spatial domain, whereas SPH computations focus on the shoreline or close to off-shore structures, where a complex description of the free-surface is required. The re-use of existing codes is achieved using a generic implementation based on Component Technology. The communication between software is ensured by the middleware Component Template Library (CTL). In order to deal with open domains, open-boundaries have to be implemented for SPH, with water height and velocity varying in space and time. These velocity and water height values are then driven by the Boussinesq-type model. As an illustration of the one way coupling, we present herein two simple examples of water waves, the first one with a flat bottom, the other one representing a schematic coastal protection