Dolors Royo

Polytechnic University of Catalonia, Barcelona, Catalonia, Spain

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Publications (30)11.06 Total impact

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    ABSTRACT: There currently are many mobile computing devices with various properties and capabilities. These devices may need to collaborate among them to allow nomad workers to perform a common activity. Unfortunately software developers in charge of creating infrastructures or applications allowing these devices to cooperate among them, do not count with clear guidelines to design such software components; particularly when these components must work in a scenario involving heterogeneous devices. This paper presents a study that tries to understand how to address collaboration among heterogeneous mobile devices, by exploring several variables affecting the process. In particular, this study explores various strategies to borrow CPU slots from peer mobile computing devices and return the favor back later on. The study outcomes indicate there is a short list of computing and network variables affecting the collaboration capability of the mobile devices. These findings have been verified using data mining techniques. Based on these findings and the lessons learned, the article presents a simulation method of computing scenarios that can help developers to determine which computing configuration would be suitable to be used in each particular work scenario. Software designers can take advantage of this simulation method and the design guidelines reported in this paper in order to develop applications able to work appropriately in heterogeneous computing scenarios.
    Integrated Computer Aided Engineering 01/2013; 20(1):59-77. · 4.67 Impact Factor
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    ABSTRACT: Advances in mobile computing and wireless communication are easing the evolution from traditional nomadic work to computer-mediated mobile collaborative work. Technology allows efficient and effective interaction among mobile users and also provides access to shared resources available to them. However, the features and capabilities of the communication infrastructure supporting these activities influence the type of coordination and collaboration employed by mobile collaborative applications in real work scenarios. Developers of these applications are typically unaware of the constraints the communication infrastructure imposes on mobile collaborative systems, because they are not easy to foresee. That leads to a high probability of communication problems in otherwise fully functional mobile collaborative support applications. This paper presents an experimental study with real devices and networks on a realistic physical environment that shows how ad hoc networks can effectively support mobile collaborative work and the practical limitations. The paper analyzes several networking issues and determines how they influence mobile collaborative work in various interaction scenarios. The paper also presents the lessons learned in the study and provides recommendations to deal with some networking issues related to real-world ad hoc networks.
    International Journal of Information Technology and Decision Making 11/2012; 11(06):1035-1063. · 1.89 Impact Factor
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    ABSTRACT: Mobile workers doing loosely coupled activities typically perform on demand collaboration in the physical workplace. Communication services available in such work scenarios are uncertain, therefore mobile collaborative applications supporting those activities must provide ad hoc communication mechanisms in order to use each cooperation opportunity. Typically, the complexity of implementing such mobile ad hoc communication mechanisms becomes a challenge that jeopardizes the development of mobile collaborative solutions. This article presents a communication infrastructure named HLMP API dealing with that challenge. HLMP API intends to ease the development of such applications through the reuse of communication services. The infrastructure is an application programming interface that implements the HLMP routing protocol and also some awareness mechanisms that are required for mobile loosely coupled work. Developers using this infrastructure do not have to perform low-level programming.
    Journal of Network and Computer Applications 11/2011; 34(6):1883-1893. · 1.77 Impact Factor
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    ABSTRACT: Advances in wireless communication systems and mobile devices allow nomad users to participate in mobile collaborative activities. However the availability of hardware resources of the mobile devices that are participating in the collaboration process is a crucial factor that can enhance or jeopardize such activity. This paper studies how the network topology and the hardware resources distributed into a network influence the collaboration among the participants in the activities. The results obtained from simulating the strategy of resource sharing in an overlay network allowed us to observe two clear implications: (1) it is important to maximize the number of links between Desktop PC and mobile devices and (2) the mobile devices have to be placed within the network topology in the nodes with higher degree. According to these observations we have proposed an heuristic for node placement in order to maximize the cooperation level in terms of resource sharing.
    Proceedings of the 2011 international conference on Computational science and its applications - Volume Part III; 01/2011
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    ABSTRACT: Advances in wireless communication systems and mobile devices allow nomad users to participate in mobile collaborative activities. However the availability of hardware resources in the mobile devices participating in the collaboration process enhances or jeopardizes such activity. This paper studies how the network topology and the hardware resources distributed into a mobile network influence the collaboration activities among the participants. Several simulations were done to try to understand this issue. The obtained results show that in mobile collaboration scenarios involving a high number of resources-constraint mobile devices (e. g. handhelds), the maximum cooperation among node is obtained in a small world network topology. The results also show that another factor that encourages cooperation among nodes is the network size.
    Computer Supported Cooperative Work in Design (CSCWD); 01/2011
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    ABSTRACT: We propose an approach for predicting group formations, to address the problem of automating the incorporation of group awareness into CSCL applications. Contextual information can enable the construction of applications that effectively assist the group members to automatically communicate in synchronous and collocated collaborative learning activities. We used data traces collected from the study of students' behavior to train and test an intelligent system. Results have shown that context-information can be effectively used as a basis for a middleware for a dynamic group management. Inferring group membership is technically viable and can be used in real world settings.
    Intelligent Environments (IE), 2010 Sixth International Conference on; 08/2010
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    ABSTRACT: Mobile collaborative applications are usually deployed in work scenarios where the existence of fixed communication infrastructure is hard to predict. For that reason, these applications use Mobile Ad hoc Networks (MANETs) to support communication between mobile users. The complexity involved in such communication infrastructures make that developers avoid developing software for mobile work scenarios. However, it is possible to provide a reusable abstraction of such communication mechanisms, in order to avoid that developers have to deal with low-level programming. This article presents HLMP API, which is an application programming interface that provides access to a HLMP implementation. This API is organized as a fully distributed mobile communication infrastructure, able to run on MANETs. This infrastructure provides an important set of services, which are required to support mobile collaboration. The reuse of these services allows developers to reduce the complexity, times and cost of these development projects. Postprint (published version)
    Proceedings of the 2010 14th International Conference on Computer Supported Cooperative Work in Design, CSCWD 2010, April 14-16, 2010, Fudan University, Shanghai, China; 01/2010
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    AI Magazine. 01/2009; 30:117-119.
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    ABSTRACT: Mobile collaboration is required in several work scenarios, i.e. education, healthcare, business and disaster relief. The features and capabilities of the communication infrastructure used by mobile collaborative applications will influence the type of coordination and collaboration that can be supported in real work scenarios. Developers of these applications are typically unaware of the constraints the communication infrastructure imposes on the collaborative system. Therefore, this paper presents an experimental study of how ad-hoc networks can effectively support mobile collaborative work. The article analyzes several networking issues and it determines how they influence the collaborative work. The paper also presents the lessons learned and it provides recommendations to deal with the networking issues intrinsic to ad-hoc networks.
    Groupware: Design, Implementation, and Use, 15th International Workshop, CRIWG 2009, Peso da Régua, Douro, Portugal, September 13-17, 2009. Proceedings; 01/2009
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    ABSTRACT: Ambient Networks will enable mobile terminals to communicate in an environments populated by several networks, devices, services and artefacts in a transparent way to the final user. In these scenarios, one way of implementing services uses web service architecture. So it is important to study how these mobile devices will integrate efficiently to access web services. Because of the reduced capabilities of the mobile devices, their access to web services is not easy and might have some performance costs related to show data speeds and processing both HTTP commands and XML. Moreover, some mobile devices could not support web service access and if supported it lacks of web service search engine. In order to allow mobile devices to access web services efficiently, giving a solution to the previous problems, we propose a new architecture based on a peer-to-peer with distributed hash tables network, as a gateway between the mobile device and web service. This architecture is a base software simulator for an Ambient Network environment developed in our research group. Nodes of the peer-to- peer network publish services, allow finding them easily and acting as a gateway to the mobile devices for accessing web services more efficiently.
    Intelligent Environments, 2008 IET 4th International Conference on; 08/2008
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    ABSTRACT: One key component of an Ambient Network are the services it offers to the users, services like calendars, agenda, object localization, network information, etc. In this paper, we propose a service naming and addressing framework (SNAF) and their implementation into the SerAN (Service advanced management for Ambient Networks) platform. SNAF is based in a decentralized distributed hash table (DHT) and a P2P Pastry system. The SNAF framework allows managing services using Web services technology. It implements two main functions: by one hand, the name service function which allows users to publish services in the SerAN platform; and by other hand the address service function which allows users to access the services. The framework offers services to heterogeneous platforms and also an interactive interface to help end users on the parameter selection for the service they have chosen.
    Intelligent Environments, 2007. IE 07. 3rd IET International Conference on; 10/2007
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    ABSTRACT: The purpose of this paper is to explain the implementation of SerAN, an advanced management platform that provides services in an ambient networking environment. We make contributions in the ambient control space and the ambient network interface implementing a decentralized distributed hash table based on a P2P pastry system. Also this paper details the implementation of an ambient service interface using Web services to publish and lookup services from different nodes into composed heterogeneous ambient networks
    Intelligent Environments, 2006. IE 06. 2nd IET International Conference on; 08/2006
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    ABSTRACT: Application layer networks are software architectures that allow the provisioning of services requiring a huge amount of resources by connecting large numbers of individual computers, like in Grid or Peer-to-Peer computing. Controlling the resource allocation in those networks is nearly impossible using a centralized arbitrator. The network simulation project CATNET will evaluate a decentralized mechanism for resource allocation, which is based on the economic paradigm of the Catallaxy, against a centralized mechanism using an arbitrator object. In both versions, software agents buy and sell network services and resources to and from each other. The economic model is based on self-interested maximization of utility and self-interested cooperation between agents.
    05/2004;
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    ABSTRACT: There has been a lot of discussion and study in the recent past about how distance learning could be improved using emerging technologies.
    05/2004;
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    ABSTRACT: There has been a lot of discussion and study in the recent past about how distance learning could be improved using emerging technologies. Collaborative tools based on the web/internet infrastructure such as e-mail, discussion groups, video/audio conferencing and virtual campuses have been proposed and implemented in many areas of distance learning. We had proposed [3] ULabGrid as a new architecture that enables educators to design collaborative, distant laboratories for undergraduate students using the Grid infrastructure. We describe here some of the changes we have made to the proposed architecture and the prototype that is being developed and present the results of our efforts to date.
    03/2004: pages 265-272;
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    ABSTRACT: This paper assumes that the deployment phase has already been carried out and services are initially located in the network. In principle, deployment can also be economically modeled, as self-interested service deployers compete for existing resources where services are to be placed, and utility-maximizing resource providers compete for the provisioning of promising new services
    12/2003;
  • Grid Computing, First European Across Grids Conference, Santiago de Compostela, Spain, February 13-14, 2003, Revised Papers; 01/2003
  • Grid Computing, First European Across Grids Conference, Santiago de Compostela, Spain, February 13-14, 2003, Revised Papers; 01/2003
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    ABSTRACT: In this work we present the CALMANT (CC-cube Algorithms on Meshes and Tori) method as a systematic method for the execution of a certain type of algorithms that are denominated CC-cube algorithms, on meshes and tori of several dimensions. It is very frequent to find CC-cube algorithms in literature (FFT, complete exchange, some methods for the single value decomposition and eigenvalue computation, etc.) but the direct application of these algorithms does not allow to exploit efficiently the bandwidth that the interconnection network offers in meshes and tori. The CALMANT method allows us to reorganize the computation and communication of the CC-cube algorithms so that the efficiency increases remarkably. The importance of this method not only lies in the improvement of the efficiency but also it can be applied in a systematic way on different types of architectures.
    06/2002;
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    ABSTRACT: The paper discusses the implementation of a parallel algorithm to compute the eigenvalues and eigenvectors of a real symmetric matrix on a mesh multicomputer. The algorithm uses the one-sided Jacobi method and a two-dimensional organization of the nodes. It is aimed at reducing the communication cost incurred by one-dimensional algorithms found in the literature. The performance of the proposed algorithm on a squared 2D/3D mesh multicomputer is assessed through simple analytical models of execution time. The models show that the performance improvement over one-dimensional algorithms can be very noticeable, specially for a large number of nodes.
    Parallel Computing 08/2001; · 1.89 Impact Factor