-The seamless continuity of services between 3G networks and WLANs will give users the feeling of a common environment towards the wireless technology. Three main aspects must be considered to obtain seamless continuity: an enabling interworking architecture, fast inter-system handovers (they must be fast enough in terms of human senses), and, in the case of real-time services, a similar quality of service (QoS) in both networks. This paper focuses on the two first issues. It presents an interworking architecture based on a 3G core-level integration of the WLANs. The GPRS network is available all the time forming a primary network, and WLANs are used as a complement when they are available. The switching times between networks are very low and the transitions are lossless. Our proposal does not disrupt with the current 3GPP standardization efforts making it viable in a medium time frame. This paper presents an overview of the architecture, describes the relevant events in the switching process (where the authentication and authorization procedures have an important role), and gives simulated values for the switching times.

No abstract

No abstract

In the current digital age, the adoption of natural interfaces between humans and machines is increasingly important. This trend is particularly significant in the education sector where interactive tools and applications can ease the presentation and comprehension of complex concepts, stimulate collaborative work, and improve teaching practices. An important step towards this vision, interactive whiteboards are gaining widespread adoption in various levels of education. Nevertheless, these solutions are usually expensive, making their acceptance slow, especially in countries with more fragile economies. In this context, we present the low-cost interactive whiteboard (LoCoBoard) project, an open-source interactive whiteboard with low-cost hardware requirements, usually accessible in our daily lives, for an easy installation: a webcam-equipped computer, a video projector, and an infrared pointing device. The detection software framework offers five different Pointer Location algorithms with support for the Tangible User Interface Object protocol and also adapts to support multiple operating systems. We discuss the detailed physical and logical structure of LoCoBoard and compare its performance with that of similar systems. We believe that the proposed solution may represent a valuable contribution to ease the access to interactive whiteboards and increase widespread use with obvious benefits.

Statistics show an aging trend in the world population, which will progressively overload existing health systems. Therefore, we believe that ubiquitous computing will play an important role in domicile settings, coping with the growing need for automated home healthcare support, especially for the sick and elderly. The integration of independently developed off-the-shelf systems (e.g., health-monitoring, entertainment, communications, home automation, etc.) may cause unplanned interactions between them (cf. feature interactions). This is a major concern since the correct/expected behavior of an isolated system may not be the same when deployed in conjunction with other systems, causing interferences, i.e., unexpected outcomes or misbehaviors. The Safe Home Care project tackles this problem to pursuit the safe deployment and reconfiguration of home healthcare smart-spaces. We propose the use of state graphs to represent off-the-shelf systems and predict the occurrence of intra-system's feature interactions. We use pre-deployment simulations to forecast feature interactions before deployment. We assess the applicability and correctness of this approach through a set of simulated home assisted living scenarios.