One important aspect of ubiquitous environments is to provide users with the possibility to freely move about and continue the interaction with the available applications through a variety of interactive devices (including cell phones, PDAs, desktop computers, digital television sets, and intelligent watches). Indeed, in such environments one big potential source of frustration is that people have to start their session over again from the beginning at each interaction device change. Migratory interactive services can overcome this limitation and support continuous task performances. This implies that interactive applications be able to follow users and adapt to the changing context of use while preserving their state.
Despite the multitude of different types of terminals available in the market, our lives have not yet become a multi-device experience since one source of constant frustration is that people cannot continue to perform their tasks when they move about and change their interaction device. This is due to the lack of migratory services technology for the migration of applications in different usage scenarios. The illustration below shows a multi-device environment mediated by the migration infrastructure.
As earlier highlighted, One important aspect of pervasive environments is to provide users with the ability to freely move about and continue the interaction with the applications in use through a variety of interactive devices with different interaction resources and communication channels with different characteristics and performance (i.e. WiFi, Bluetooth, sensor networks, UMTS, e.t.c). In this regard, there has been a recent increase in interest in migratory interactive services. They provide users with the ability to change the interaction device and still continue their tasks through an interface adapted to the new platform. Migration can involve various types of devices. In some cases, migration can be used to improve the user’s experience by switching to a better suited devices (bigger screen, more graphical power, e.t.c) or to a more efficient communication channel/a communication channel that can guarantee better QoS (shorter delays, higher bandwidth).
In order to address the complex issues related to migration there is a need for a service platform able to consider and integrate various aspects: adapt and preserve the state of the software application parts dedicated to interacting with end users; support mechanisms for application logic reconfiguration; and define suitably flexible mechanisms from the underlying network layers. The resulting service platform should be able to interoperate with existing technologies. In general, a service is a computer-based entity that provides well-defined functionality, together with the policies that should control their usage.
Migratory interactive applications require that the user interface adapts itself to the resources and the existing services of the new device/environment; this can also imply dynamic (re)configuration of the overall application, which in turn involves establishing the required/requested connections between the available components/ services, which are user interface components, as well as non-user interface components providing application services. Migratory Interactive Services also imply an intelligent context-aware infrastructure able to capture the state of the user interface and application logic on the source device, transmit it to the target device (transformed if necessary) and then generate an appropriate user interface to the target device as well. The devices used for interaction can support various modalities (graphical, vocal, gesture, e.t.c), which can even be exploited in various combinations depending on the context of use. We also address partial/distributing migration, which is the ability to move from interacting with an application through a single device, to interaction through several coordinated devices using various modalities. This allows users to comfortably control, for example, videos displayed on a wall-sized screen through a vocal interface, or project a presentation stored in a personal device such as a PDA to a desktop-controlled maxi video screen in a conference hall while annotating the output through an intelligent whiteboard and maintaining control on the personal device. Migration of an interactive service to a set of devices detected and classified on the basis of the tasks supported by their resources can require complex processing.
