Ambient computing applications: an experience with the SPREAD approach

Abstract

Todays, we assist to the explosive development of mobile computing devices like PDAs and cell-phones, the integration of embedded intelligence (like Web server) in more and more common devices, and the proliferation of wireless communication technologies (IRdA, Bluetooth, IEEE 802.11, GPRS). All these trends contribute to move us closer to the ubiquitous computing world described by Mark Weiser.But while the technology is here, applications, and more important, models and tools for designing future ambient computing systems are still rare. One of the first innovative concept of ubiquitous computing, context-awareness, is still hard to use and understand from a programming perspective. We think that the problem resides in the lack of system support : in traditional computing, operating system offers simple to use and easy to understand abstractions of computational resources. Ubiquitous computing involves an integration of "computing" into the real-world, which is a radically different environment for applications. We think that this environment requires new operating system services and abstractions. Because the real world is made of physical entities, "living" in the physical space, ambient computing software should be able to use abstraction representing such objects, in a simple way.In this paper, we present a light framework to design ubiquitous computing software, called SPREAD. Unlike many approaches which hides too much of the real-world behind traditional computing abstraction, SPREAD defines programming abstraction based on the properties of the physical space. Hence, physical properties, like relative proximity, are used as implicitly in SPREAD as variable addressing in a computer memory. In SPREAD, application (or process) behavior can be "mechanically" driven, in the sense that actions flow can be directly dependent of physical mobility.To support this concept, we introduce a programming and execution model allowing to design computing and information systems driven directly by arranging and moving physical objects in the space. We demonstrate the use of the model to implement a few practical applications, highlighting its simplicity and expression power.

An experimental evaluation of self-managing availability in shared data spaces

“…In this way, queries can be matched against tuples when a data space comes in proximity of an outstanding read operation. A similar approach has also been explored in the SPREAD system [4]. Again, fault tolerance is not explicitly addressed, but can easily be incorporated as a separate concern using techniques that are independent from those used to support mobility.…”

Linda in Space-Time: An Adaptive Coordination Model for Mobile Ad-Hoc Environments

“…The application example shown in Section 4.2 is also related to Geo-Linda [24], another example of spatial coordination approach combining the tuple manipulation of LINDA with the geometric addressing concepts of SPREAD [13]. In Geo-Linda, tuples are read and published over an assortment of geometric primitives, such as boxes, spheres, cylinders, and cones, all defined relative to a device.…”

Message Quality for Ambient System Security

“…The tuples in a principal's tuple space can be read by all other principals in its network vicinity; see Figure 3. Many systems designed for ambient environments employ Linda's tuple space model for the reasons cited above, e.g., Lime [14], Spread [4]. The list of operations is presented in Figure 3.…”