Pedro Sobral

Seamless continuity of PS-services in WLAN/3G interworking

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.

UMTS-WLAN Service Integration at core network level

The integration of wireless LANs (WLANs) and 3G systems performed at core network level requires very little modifications to the current 3GPP architecture and provides a large set of benefits: seamless service integration, exploration of user mobility by applications, seamless use of different radio access network (RANs), easy availability of current services such as Short Message Service (SMS) in other RANs, etc. This paper describes an architecture that has the GPRS as the primary network. Each of the other networks has a 3G core-level component to manage it and to perform the integration. Vertical handovers between RANs are not needed and secondary networks are used on an availability basis. Users can have at least one session per RAN that is maintained even when they are moving in dark areas of that RAN (and the communication is still possible via the primary network). Our proposal does not require the system to be all-IP, but simply IP-enabled.

Prognostic of feature interactions between independently developed pervasive systems

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-systems 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.

LoCoBoard: Low-Cost Interactive Whiteboard Using Computer Vision Algorithms

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.

A graph-based approach for interference free integration of commercial off-the-shelf elements in pervasive computing systems

Abstract Commercial off-the-shelf devices and applications are expected to be pivotal in the coming massive deployment of pervasive computing technology in home settings. The integration of these devices and applications in the same household may result in unplanned interactions involving users and entertainment, communication, and health-related devices and applications. These unplanned interactions are a serious concern when, for example, communication or entertainment applications interfere with the behavior of health-related devices. This paper presents a novel graph-based approach for representing the expected behavior of commercial off-the-shelf devices and applications, their interactions, and for detecting interference in pervasive computing systems. A set of home care scenarios is used to assess the applicability of this approach. We then provide two setups where this approach can be applied: (i) in a pre-deployment setup, where simulation is used to detect possible instances of interference, and (ii) at run-time, collecting observations from devices and applications and detecting interference as it occurs. For pre-deployment and simulation we use Opensim to recreate a home household. For run-time, we use Simple Network Management Protocol for systems state introspection and a sliding window mechanism to process the collected data-stream.

Interference Free Integration of Pervasive Applications

Off-the-shelf smart devices and applications are expected to be pivotal in the coming need for massive home care. Deployment and integration of these systems in the same household may result in unplanned interactions involving users and entertainment, communication, and health-related devices. These unplanned interactions are a major concern when, for example, communication or entertainment applications interfere with the behavior of health-related devices. This paper presents a novel graph-based approach for representing the expected behavior of off-the-shelf smart devices and applications, their interactions, and for detecting interference in home care settings. A set of home care scenarios is used to assess the applicability of our approach. Our graph-based interference detection approach is integrated in the Safe Home Care reflective platform, which allows reifying the state of off-the-shelf systems and simulating home care scenarios.

Graph-based approach for interference free integration of pervasive applications

Smart-space modeling is a fundamental requirement towards the achievement of safe integration of pervasive systems and devices. Traditional behavior models lack explicit representation of rich semantic for ubicomp systems. We propose a graph-based model supporting ubicomps computational, physical, user and temporal contextual information. The model is part of a solution to tackle the interference problem, which results from unexpected interactions involving users and entertainment, communication, and health-related devices. This is a major concern when, for instance, daily routines are affected by different types of applications. The proposed graph-based interference detection is integrated in the Safe Home Care reflective platform, and allows reifying systems state and simulating home care scenarios. A set of home care scenarios are used to assess the applicability and correctness of our approach.

Dynamic adaptation of personal ubicomp environments

A significant challenge for personal and ubiquitous computing is to cope with frequent changes of user preferences, profile, location, and context in general. In this special issue we bring you an update on how dynamic adaptation is being used to address this challenge. Dynamic adaptation provides runtime modeling and monitoring of both structural and behavioral aspects, possibly at different levels of the open systems interconnection (OSI) model. We are thinking in particular of personal and ubiquitous computing environments assembled from a variety of custom-of-theshelf (COTS) systems that are planned to work independently of each other. Dynamic adaptation opens the door to reason about and undertake policies and strategies without compromising the functionality and integration of COTS systems in the environment. The papers in this special issue cover different aspects of dynamic adaptation in PUC.

Indoor Location Using Bluetooth Low Energy Beacons

Location data plays an important role in several applications embedded in our digital living. These applications, usually, take advantage of Global Positioning System (GPS). However, GPS is not targeted for indoor location, therefore this paper presents an alternative system, based on Bluetooth Low Energy (BLE) beacons that together with bluetooth-enabled Smartphones, allows the development of low cost and accurate location-aware applications for indoor scenarios. The paper describes the challenges associated with the system deployment and presents algorithms to improve the distance estimation process as the user moves around the smart space. The evaluation performed shows that this approach has good results on noise reduction and movement adaptation allowing a close tracking of the indoor user position.

Service integration between wireless systems

The greater bandwidth provided by wireless LANs can be a precious asset to the wireless ubiquitous computing if the integration with 3GPP systems is done at a certain level. This paper presents a proposal to integrate wireless systems at core network level. Service integration becomes very powerful and easy. The system is not so dependent on the critical latency of vertical handovers and the users feel a unique system providing services. Little changes are required to the current 3GPP core network. Our architecture uses the GPRS as the primary network and integrates WLANs as secondary networks, used on an availability basis. Sessions on secondary networks survive disconnection periods contributing to a seamless service provision to the user. The paper describes the overall architecture, the changes that are needed at the current 3GPP core, and the operation of the secondary networks on the aspects of data routing and security associations. Highlights about the application model are presented at the end.