1,721,116 research outputs found
Efficiently Managing Location Information with Privacy Requirements in Wi-Fi Networks: a Middleware Approach
No full textThe growing availability of wireless portable devices is leveraging the diffusion of Location Based Services (LBSs) that provide service con-tents depending on the current position of clients, servers, and involved distributed resources. When a wide public of final users will use LBSs, two primary issues will emerge as crucial: how to guarantee the proper level of user privacy given the need to disclose, to some extent, client location information; how to effectively manage the exchange of positioning information (and of its variations) notwithstanding the high heterogeneity of connectivity technologies and device hardware/software capabilities. The paper pre-sents the privacy-related extension of our proxy-based mobile agent middleware to support per-sonalized service provisioning to Wi-Fi portable devices. In particular, our middleware prototype adopts a two-level proxy-based architecture to provide LBSs with middleware-mediated effective access to location data, which are exposed at the proper level of granularity depending on privacy/efficiency requirements dynamically ne-gotiated between clients and LBSs
PreQuEst: a Scalable and Proactive Quality Enrichment for Presence Services
No full textThe market growth of VoIP infrastructures and services is pushing towards additional facilities to enrich service offer in an open way, thus representing also a differentiating aspect and a competitive advantage for service providers. We claim that the proactive provisioning of estimations about runtime VoIP quality is a crucial facility still missing in VoIP services: for instance, such a facility could be integrated within a Presence Service to inform users of expected quality of VoIP communications towards their contacts before calling them. The paper proposes a novel and scalable solution for proactive quality monitoring, specifically designed for VoIP traffic and based on proper runtime decisions about network partitioning. On top of this monitoring layer, we have designed and implemented an effective and flexible application-level facility for end-to-end QoS estimation, exploited by an enriched Presence Service in the examined case study. The paper describes the practical experience and the lessons learned in implementing an industrial prototype of the proposal, which is integrated with standard and widespread mechanisms (e.g., SIP Voice Quality Report Event, SIP Answer Mode and SDP Media Loopback extensions) in order to facilitate market diffusion and acceptance. First preliminary experimental results show that the proposed prototype achieves accurate quality evaluations and is largely more scalable than traditional end-to-end approaches
Enhancing JSR-179 for Positioning System Integration and Management
No full textSeveral heterogeneous positioning systems are more and more widespread among client wire-less terminals, thus leveraging the market relevance of Location Based Services (LBSs). Positioning techniques are very differentiated, e.g., in terms of precision, accuracy, and battery/bandwidth consumption, and several of them are simultaneously available at clients. That motivates novel middleware solutions capable of integrating the dynamically accessible positioning techniques, of controlling them in a synergic way, and of switching from a positioning system to another at service provisioning time by choosing the most suitable solution depending on application-level LBS context. In this perspective, the paper proposes the original PoSIM solution, which significantly extends the emerging JSR-179 standard specification to allow differentiated forms of visibility/control of low-level positioning characteristics, greater flexibility in lo-cation change-driven event triggering, and the simultaneous management of multiple and dynamically introduced location techniques
Mobility-Aware Connectivity for Seamless Multimedia Delivery in the Heterogeneous Wireless Internet
No full textThe diffusion of wireless terminals with multiple communication interfaces, e.g., IEEE 802.11, Bluetooth, and UMTS on the same device, is pushing towards the necessity of middleware solutions to dynamically and seamlessly select the proper connectivity technology to exploit at any time. That selection should consider several elements, at very different abstraction layers, from application bandwidth to energy consumption requirements, from connectivity costs to user preferences, i.e., it should be context-dependent. The paper presents our context-aware MAC middleware for multi-interface wireless terminals that enables the dynamic determination and selection of the most suitable interface and connectivity provider among the available ones. MAC novelty is primarily in two crucial challenging elements. On the one hand, it considers not only infrastructure-based connectivity providers, e.g., UMTS base stations, but also peer nodes, e.g., neighbor nodes accessible via Bluetooth and connected via Wi-Fi to the Internet infrastructure. On the other hand, MAC can evaluate both infrastructure and peer connectivity providers not only based on usual parameters such as available bandwidth and energy consumption, but also taking into account innovative and crucial indicators such as the degree of mobility, even relatively to mo-bile connecting clients
A layered infrastructure for mobility-aware best connectivity in the heterogeneous wireless internet
Full text linkThe common availability of wireless devices with multiple communication interfaces, e.g., IEEE 802.11, WiMAX, Bluetooth, and/or UMTS, is pushing towards the necessity of novel supports to seamlessly select the proper connectivity technology to exploit at any time. That selection should be context-dependent and consider several aspects, at very different abstraction layers, from application-specific bandwidth requirements to expected client mobility, from connectivity costs and energy consumption to user preferences. We claim the need of effective mobility-aware middleware solutions to relieve application logic from the burden of determining the most suitable interface and connectivity provider for each client at runtime. In particular, we claim that such middleware supports should be structured according to a two-layer architecture: a lower-layer facility to retrieve available interfaces and connectivity providers and to discard unsuitable ones with a per-node decision, e.g., to reduce power consumption; and a higher-layer facility to select the currently most suitable connectivity provider in a per-application way. The paper describes the design and implementation of our novel middleware built according to those architecture guidelines: that permits to clearly differentiate lower-level wireless interface management and connectivity evaluation from higher-level monitoring/selection, thus simplifying the separation between node- and application-specific requirements and the dynamic introduction of new connectivity evaluation metrics. In addition, to take mobility-aware connectivity decisions, our middleware effectively exploits the predicted degree of client node mobility, estimated in a completely autonomous decentralized way. The reported experimental results demonstrate the feasibility of the approach, with accurate estimations of node mobility associated with very limited overhead
Mobility Prediction for Mobile Agent-based Service Continuity in the Wireless Internet
No full textNew challenging deployment scenarios are integrating mobile devices with limited and heterogeneous capabilities that roam among wireless access localities during service provisioning. This calls for novel middleware solutions not only to support different forms of mobility and connectivity in wired-wireless integrated networks, but also to perform personalized service reconfigura-tion/adaptation depending on client characteristics and in response to changes of wireless access locality. The paper proposes the adoption of Mobile Agent (MA) proxies working at the wired-wireless network edges to support the personalized access of limited wireless clients to their needed resources on the fixed network. In particular, the paper focuses on how to predict device mobility between IEEE 802.11 cells in a portable lightweight way, with no need of external global positioning systems. In fact, we claim that mobility prediction is crucial to maintain service continuity: MA-based proxies can migrate in advance to the wireless cells where mobile clients are going to reconnect to, in order to anticipate the local re-arrangement of personalized sessions. The paper proposes and evaluates different mobility prediction solutions based on either client-side received signal strength or Ekahau positioning, all integrated in the SOMA platform. Both simulation and experimental results show that SOMA can predict the next visited cell with a very limited overhead and enough in advance to maintain service continuity for a large class of wireless Internet services
Coupling Transparency and Visibility: a Translucent Middleware Approach for Positioning System Integration and Management (PoSIM)
Full text linkThe diffusion of wireless terminals with multiple communication interfaces and the proliferation of heterogeneous positioning techniques opens new possibilities for Location Based Services (LBSs), even if potentially complicating their development In particular, LBSs can significantly benefit from middleware supports to uniformly access the set of positioning systems available at their wireless clients and to dynamically choose the most suitable one depending on application/execution context, also by fusing concurrent positioning data from multiple sources. The paper presents our PoSIM middleware for the integrated and synergic access/control of heterogeneous positioning systems in a highly flexible way. PoSIM provides LBSs with two differentiated levels of visibility for positioning management: a transparent way based on high-level context-based policies, and a fully-aware access to advanced functions/configurations, mediated and uniformed by the middleware independently of the underlying positioning solution. In particular, the paper mainly concentrates on the description of the PoSIM architecture and of its API, by pointing out our primary design and implementation choices
QoS Management Middleware Solutions for Bluetooth Audio Distribution
No full textA primary challenge in the mobile Internet scenario is the dynamic differentiation of provided levels of Quality of Service (QoS) depending on client characteristics and current resource availability. In this context, the paper presents how the application-level ubiQoS middleware supports the provisioning of audio applications with different QoS levels over the last Bluetooth segment to wireless devices. To this purpose, ubiQoS dynamically deploys mobile proxies, acting as masters in Bluetooth piconets, to properly configure and manage Bluetooth connections at runtime. Audio applications working on top of ubiQoS can easily exploit differentiated QoS by simply specifying different user classes and terminal profiles. ubiQoS proxies exploit JSR82ext, a newly developed Java library that extends the JSR82 specification for Java-based Bluetooth communication facilities with richer QoS management functions for all types of Bluetooth connections. The reported experimental results show that our Java-based implementation can dynamically support differentiated QoS levels for audio traffic, with an efficient usage of the available Bluetooth bandwidth
A Mobile Computing Middleware for Location- and Context-Aware Internet Data Services
No full textThe widespread diffusion of mobile computing calls for novel services capable of providing results that depend on both the current physical position of users (location) and the logical set of accessible resources, subscribed services, preferences, and requirements (context). Leaving all the burden of location/context management to applications complicates service design and development. In addition, traditional middleware solutions tend to hide location/context visibility to the application level and are not suitable for supporting novel adaptive services for mobile computing scenarios. The paper proposes a flexible middleware for the development and deployment of location/context-aware services for heterogeneous data access in the Internet. A primary design choice is to exploit a high-level policy framework to simplify the specification of services that the middleware dynamically adapts to the client location/context. In addition, the middleware adopts the mobile agent technology to effectively support autonomous, asynchronous, and local access to data resources, and is particularly suitable for temporarily disconnected clients. The paper finally presents the case study of a museum guide assistant service that provides visitors with location/context-dependent artistic data. The case study points out the flexibility and usability of the proposed middleware that permits automatic service reconfiguration with no impact on the implementation of the application logic
Integrating Mobile Agent Infrastructures with CORBA-based Distributed Multimedia Applications
No full textThe increased computing power and the enhanced connectivity of current open computing systems are encouraging the deployment of new classes of services both centered around dynamically changing user requirements and based on the exploitation of the Internet infrastructure. Distributed Multimedia Applications (DMAs) are a typical class of services with challenging requirements in terms of resource demand, dynamicity and QoS adaptation. The paper claims that distributed objects and mobile agents can complement each other to provide a flexible middleware for DMAs, and describes the case study of MADAMA (Mobile Agent-based Distributed Architecture for Multimedia Applications). MADAMA adopts mobile agents to simplib the distribution of service control and to provide location-aware adaptability. In addition, MADAMA is compliant with CORBA to achieve large ac- cessibility and interoperability
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