Hans-Werner Gellersen

There is more to context than location

Abstract Context is a key issue in interaction between human and computer, describing the surrounding facts that add meaning. In mobile computing location is usually used to approximate context and to implement context-aware applications. We propose that ultra-mobile computing, characterized by devices that are operational and operated while on the move (e.g. PDAs, mobile phones, wearable computers), can significantly benefit from a wider notion of context. To structure the field we introduce a working model for context, discuss mechanisms to acquire context beyond location, and application of context-awareness in ultra-mobile computing. We investigate the utility of sensors for context-awareness and present two prototypical implementations — a light-sensitive display and an orientation-aware PDA interface. The concept is then extended to a model for sensor fusion to enable more sophisticated context recognition. Based on an implementation of the model an experiment is described and the feasibility of the approach is demonstrated. Further, we explore fusion of sensors for acquisition of information on more sophisticated contexts.

Smart-Its Friends: A Technique for Users to Easily Establish Connections between Smart Artefacts

Ubiquitous computing is associated with a vision of everything being connected to everything. However, for successful applications to emerge, it will not be the quantity but the quality and usefulness of connections that will matter. Our concern is how qualitative relations and more selective connections can be established between smart artefacts, and how users can retain control over artefact interconnection. We propose context proximity for selective artefact communication, using the context of artefacts for matchmaking. We further suggest to empower users with simple but effective means to impose the same context on a number of artefacts. To prove our point we have implemented Smart-Its Friends, small embedded devices that become connected when a user holds them together and shakes them.

Multi-sensor context-awareness in mobile devices and smart artifacts

The use of context in mobile devices is receiving increasing attention in mobile and ubiquitous computing research. In this article we consider how to augment mobile devices with awareness of their environment and situation as context. Most work to date has been based on integration of generic context sensors, in particular for location and visual context. We propose a different approach based on integration of multiple diverse sensors for awareness of situational context that can not be inferred from location, and targeted at mobile device platforms that typically do not permit processing of visual context. We have investigated multi-sensor context-awareness in a series of projects, and report experience from development of a number of device prototypes. These include development of an awareness module for augmentation of a mobile phone, of the Mediacup exemplifying context-enabled everyday artifacts, and of the Smart-Its platform for aware mobile devices. The prototypes have been explored in various applications to validate the multi-sensor approach to awareness, and to develop new perspectives of how embedded context-awareness can be applied in mobile and ubiquitous computing.

Mediacups: experience with design and use of computer-augmented everyday artefacts

Abstract Our view of ubiquitous computing is artefact-centred: in this view, computers are considered as secondary artefacts that enable items of everyday use to communicate as networked digital artefacts. This view is expressed in an artefact computing model and investigated in the Mediacup project, an evolving artefact computing environment. The Mediacup project provides insights into the augmentation of artefacts with sensing, processing, and communication capabilities, and into the provision of an open infrastructure for information exchange among artefacts. One of the artefacts studied is the Mediacup itself, an ordinary coffee cup invisibly augmented with computing and context-awareness. The Mediacup and other computer-augmented everyday artefacts are connected through a network infrastructure supporting loosely coupled spatially defined communication.

Beyond prototypes: challenges in deploying ubiquitous systems

The authors discuss the problems in creating the next generation of widely deployed ubiquitous computing systems and articulate current technical and sociological challenges to inspire researchers in the field. They discuss significant research challenges that have yet to be addressed. Central to documenting these challenges is recognizing the context within which we are operating, so they first describe the technical and social changes of the 1990s that directly affected ubiquitous computing then.

Object-oriented Web application development

Most Web applications are still developed ad hoc. One reason is the gap between established software design concepts and the low-level Web implementation model. We summarize work on WebComposition, a model for Web application development, then introduce the WebComposition Markup Language, an XML-based language that implements the model. WCML embodies object-oriented principles such as modularity, abstraction and encapsulation.

A relative positioning system for co-located mobile devices

If a mobile computing device knows how it is positioned and oriented in relation to other devices nearby, then it can provide enhanced support for multi-device and multi-user interactions. Existing systems that provide position information to mobile computers are reliant on externally deployed infrastructure, such as beacons or sensors in the environment. We introduce the Relate system, which provides fine-grained relative position information to co-located devices on the basis of peer-to-peer sensing, thus overcoming dependence on any external infrastructure. The system is realised as a hardware/software plug-in, using ultrasound for peer-to-peer sensing, USB to interface with standard mobile devices, and data abstraction and inferencing to map sensor data to a spatial model that maintains both quantitative and qualitative relationships. We present a set of services and applications to demonstrate the utility of the system. We report experimental results on the accuracy of the relative position and orientation estimates, and other aspects of system performance.

The MediaCup: Awareness Technology Embedded in a Everyday Object

The MediaCup is an ordinary coffee cup augmented with sensing, processing and communication capabilities, to collect and communicate general context information in a given environment. In this project, coffee cups are computerized to integrate them and the information they hold--where the cup is, how it is handled, and whether its hot or cold--as context into surrounding information ecologies.

Cooperative Artefacts: Assessing Real World Situations with Embedded Technology

Ubiquitous computing is giving rise to applications that interact very closely with activity in the real world, usually involving instrumentation of environments. In contrast, we propose Cooperative Artefacts that are able to cooperatively assess their situation in the world, without need for supporting infrastructure in the environment. The Cooperative Artefact concept is based on embedded domain knowledge, perceptual intelligence, and rule-based inference in movable artefacts. We demonstrate the concept with design and implementation of augmented chemical containers that are able to detect and alert potentially hazardous situations concerning their storage.

Context Acquisition Based on Load Sensing

Load sensing is a mature and robust technology widely applied in process control. In this paper we consider the use of load sensing in everyday environments as an approach to acquisition of contextual information in ubiquitous computing applications. Since weight is an intrinsic property of all physical objects, load sensing is an intriguing concept on the physical-virtual boundary, enabling the inclusive use of arbitrary objects in ubiquitous applications. In this paper we aim to demonstrate that load sensing is a versatile source of contextual information. Using a series of illustrative experiments we show that using load sensing techniques we can obtain not just weight information, but object position and interaction events on a given surface. We describe the incorporation of load-sensing in the furniture and the floor of a living laboratory environment, and report on a number of applications that use context information derived from load sensing.