Oscar Ardaiz

Tag Mechanisms Evaluated for Coordination in Open Multi-Agent Systems

Tags are arbitrary social labels carried by agents. When agents interact preferentially with those sharing the same Tag, groups are formed around similar Tags. This property can be used to achieve desired group coordination by evolving agents Tags through a group selection process. In this paper Tags performance is for the first time compared by simulation with alternative mechanisms for coordinated learning in multi-agent systems populations. We target open systems, hence we do not make costly assumptions on agent capabilities (rational or computational). It is a requirement that coordination strategies prove simple to implement and scalable. We build a simulator incorporating competition and cooperation scenarios modeled as one-shot repeated games between agents. Tags prove to be a very good coordination mechanism in both, cooperation building in competitive scenarios and agent behavior coordination in fully cooperative scenarios.

An architecture for incorporating decentralized economic models in application layer networks

Efficient resource discovery and allocation is one of the challenges of any large scale Application Layer Network (ALN) such as computational Grids, Content Distribution Networks and P2P applications. In centralized approaches, the user requests can easily be matched to the most convenient resource. These approaches, however, present scalability limits in the highly dynamic and complex ALN environments. This paper, explores an architecture for incorporating fully decentralized economic mechanisms for resource allocation. These mechanisms are implemented by a set of trading agents that operate on behalf of the clients and service providers, interacting over an overlay network and interfacing with the underlying resources of the platform. A prototype of the proposed architecture is presented and the practical implications of its implementation in a grid scenario are discussed.

CollARt: a tool for creating 3D photo collages using mobile augmented reality

A collage is an artistic composition made by assembling different parts to create a new whole. This procedure can be applied for assembling tridimensional objects. In this paper we present CollARt, a Mobile Augmented Reality application which permits to create 3D photo collages. Virtual pieces are textured with pictures taken with the camera and can be blended with real objects. A preliminary user study (N=12) revealed that participants were able to create interesting works of art. The evaluation also suggested that the possibility of itinerantly mixing virtual pieces with the real world increases creativity.A collage is an artistic composition made by assembling different parts to create a new whole. This procedure can be applied for assembling tridimensional objects. In this paper we present CollARt, a Mobile Augmented Reality application which permits to create 3D photo collages. Virtual pieces are textured with pictures taken with the camera and can be blended with real objects. A preliminary user study (N=12) revealed that participants were able to create interesting works of art. The evaluation also suggested that the possibility of itinerantly mixing virtual pieces with the real world increases creativity.

Virtual collaborative environments with distributed multitouch support

In this paper, we present a new application framework aimed to support distributed synchronous collaboration using multitouch interaction. The framework supports 2D and 3D virtual workspaces that enable two or more users to collaboratively or cooperatively manipulate shared objects with multitouch interfaces. We present two applications developed with the aim to explore 2D/3D immersive collaborative environments with multitouch interaction. We also present our experience and preliminary results in designing, developing and integrating these applications on educational settings.

Interacting with multi-touch handheld devices in augmented reality spaces: effects of marker and screen size

During the last years popularity of Augmented Reality (AR) has grown considerably. Nowadays most people have handheld devices equipped with camera, a variety of sensors and high computational power capable of rendering graphics previously only available on desktop computers. Such devices have replaced buttons with multi-touch screens as their main input system. In this paper we design and implement a technique for multi-touch handheld devices to manipulate objects in three-dimensional spaces. By mean of three experiments we studied the effect of workspace and device size on the performance.

A Group Selection Pattern Applied to Grid Resource Management

A key challenge in grid computing is the achievement of efficient and self-organized resource management. Grids are often large scale, heterogeneous, and unpredictable systems. Introducing group structures can help to distribute coordination efforts, but higher levels of adaptation and learning in the coordination protocols are still required in order to cope with system complexity. We provide a solution based on a self-organized and emergent mechanism evolving congregations of resource management agents through a group selection process which maximizes utility outcomes for system-wide performance. We provide a formalization of this process into a group selection pattern, and we propose several instantiations optimizing grid resource management scenarios such as adaptive job scheduling, market-based resource management, and policy coordination in virtual organizations (VOs). We further evaluate by simulation the performance of the mechanism in those scenarios. The results support the conclusion that group selection optimizes coordination by evolving small and dynamic groups.

A group selection pattern optimizing job scheduling in decentralized grid markets

Decentralized economic models are being considered as scalable coordination mechanism for the management of service allocations to clients. However, decentralization incorporates further dynamicity and unpredictability into the system, degrading its performance. In this paper, a solution based on a self-organized and emergent Group Selection mechanism is proposed. Dynamic congregations evolve Grid Markets participants (c and service providers) into optimized market segments, maximizing utility outcomes for system-wide performance. We provide evaluation by simulation of the Group Selection mechanism performance in a market-based resource management and job scheduling scenario for Grid computing, compared with alternative scheduling strategies such as economic in a flat population (not using groups), random and least loaded resource selection.

Distributed multi-touch virtual collaborative environments

We present a Remote Multi-touch Collaborative Environment that integrates videoconferencing in an immersive shared space. The proposed solution supports synchronous remote and co-located interactions of two or more users sharing the same virtual workspace. Two applications, that incorporate 2D and 3D shared space, have been developed.

Optimising decentralised grid markets through group selection

Automatic coordination mechanisms for the grid are required due to the increasing complexity that is exhibited in large-scale distributed systems. Decentralised economic models are being considered as scalable coordination mechanisms for the management of service allocations to clients. However, decentralisation incorporates further dynamicity and unpredictability into the system. Introducing higher levels of adaptation and learning in the coordination protocols helps cope with complexity. We provide a solution based on a self-organised, emergent mechanism that evolves grid market participants through a group selection process. Dynamic congregations organise agents into optimised market segments, maximising utility and thereby improving system-wide performance. We provide a system model and evaluation by simulating the group selection mechanism. We further provide a prototype that shows the practical feasibility of the approach.

Wikideas and creativity connector: supporting group ideational creativity

In Ideation2.0 project [1] we are researching, developing and testing Web2.0 technologies to support group ideational creativity. We use wiki technologies in Wikideas tool to allow brainstorming sessions that gather large number of ideas which can be visualized later by other group members, thus enabling the generation of new ideas. Creativity Connector is a tool that is integrated with Wikideas and whose mission is to connect anonymous users into brainstorming groups to produce a greater number of innovative and original ideas. We consider that with their utilization will reduce participants apprehension to be evaluated and will bring about a significant improvement in group ideacional creativity. The assessment of these tools has been carried out in a study with a sample of 50 university students of software engineering and social worker degrees.In Ideation2.0 project [1] we are researching, developing and testing Web2.0 technologies to support group ideational creativity. We use wiki technologies in Wikideas tool to allow brainstorming sessions that gather large number of ideas which can be visualized later by other group members, thus enabling the generation of new ideas. Creativity Connector is a tool that is integrated with Wikideas and whose mission is to connect anonymous users into brainstorming groups to produce a greater number of innovative and original ideas. We consider that with their utilization will reduce participants apprehension to be evaluated and will bring about a significant improvement in group ideacional creativity. The assessment of these tools has been carried out in a study with a sample of 50 university students of software engineering and social worker degrees.