Building complex simulations is usually a challenge, mainly due to the broad spectrum of concepts that must be taken into account. Simulation middleware based on the IEEE 1516 standard tries to reduce this complexity, but there are still aspects that hinder the implementation of such simulations. The dependency between the source code and the corresponding formal description of the model could be hard to verify and maintain. Also, the code for the model simulation and the code needed for the integration with the HLA/RTI middleware coexist becoming complex and error prone. In this paper we propose a new framework based on metadata (Java annotations or C# attributes) that faces these problems and extends the IEEE 1516-2010 standard. In addition, we present an implementation of the IEEE 1516 standard in the C# language. Finally, we explain our experience in implementing the standard in C#.

Abstract The main purpose of the present study is to analyze the suitability of performance‐based scheduling strategies for High Throughput Computing applications applied to Federated Grids consisting of several Grid infrastructures. The infrastructures forming aFederated Grid are classified as internal or external. This is because our scheduling policies map as much jobs as possible first to internal resources. In this way the mapping strategies save time and communication bandwidth by exploiting the location of the internal resources and the membership to their respective resource domains. At the same time, the policies avoid overloading external resources facilitating the cooperation between organizations to share resources. In this paper we consider three new algorithms for scheduling in situations where there are several Grid infrastructures of different types: enterprise, partner, or utility. Copyright © 2009 John Wiley & Sons, Ltd.

It is difficult to build user interfaces that must be distributed over a set of dynamic and heterogeneous I/O devices. This difficulty increases when we want to split, merge, replicate, and relocate the UI across a set of heterogeneous devices, without the application intervention. Furthermore, using generic tools, e.g. to search for UI components or to save/restore them, is usually not feasible. We follow a novel approach for building UIs that overcomes these problems: using distributed file systems that export widgets to applications. In this paper we describe Omero, a UI server built along this line for the plan B operating system

The conventional approach for building pervasive environments relies on middleware to integrate different systems. Instead, we have built a system that can deal with these environments by exporting system resources through distributed virtual file systems. This requires no middleware, simplifies interoperation, and permits applying general purpose tools to any system resource. A constraint-based file system import mechanism allows the system to adapt to changes in the environment and permits users to customize the environment and tailor adaptation according to their needs. The system has been in use for over a year to carry out our daily work and is underlying the smart space that we built for our department

There is a huge effort in ongoing research on new middleware platforms and new distributed services to support ubiquitous environments and pervasive applications. Prototypes for smart spaces are sometimes used to demonstrate the need for a new particular service, piece of software, or middleware layer. However, we have found that we could easily build a smart space and some applications for it by relying on services already provided by the system we use daily, Plan 9 from Bell Labs. This paper explores how far can we go with a traditional system to support a ubiquitous environment, without using any middleware. We describe how to build a pervasive computing platform using Plan 9, and how we built a smart space to demonstrate this