Pervasive Computing

Services are capabilities that enable applications and are of crucial importance to pervasive computing in next-generation networks. Service Composition is the construction of complex services from primitive ones; thus enabling rapid and flexible creation of new services. The presence of multiple independent service providers poses new and significant challenges. Managing trust across providers and verifying the performance of the components in composition become essential issues. Adapting the composed service to network and user dynamics by choosing service providers and instances is yet another challenge. In SAHARA¹, we are developing a comprehensive architecture for the creation, placement, and management of services for composition across independent providers. In this paper, we present a layered reference model for composition based on a classification of different kinds of composition. We then discuss the different overarching mechanisms necessary for the successful deployment of such an architecture through a variety of case-studies involving composition.

Examples for ubiquitous computing applications usually come from the household domain. Typical lists include microwave ovens with integrated web-pads, refrigerators or washing machines with remote Internet connections for maintenance access, and even instrumented coffee mugs or clothes. While many of these examples have substantial entertainment value, the likelihood of their realization and pervasive deployment in the not too distant future is questionable. There is, however, another application domain for ubiquitous computing which holds substantial promise, but is often overlooked: the automotive sector.

Cars are fairly attractive protagonists for ubiquitous computing: They are large enough to have communication devices integrated in them, in fact, a substantial portion of them has integrated phones today. They come with their own power source which can also feed their communications equipment. Their price is some orders of magnitude higher than that of the device to be included, so the relative price increase to make them communicate is small. And, perhaps most importantly, some services such as mayday, remote tracking, or telediagnosis make vehicle connectivity desirable for car buyers and car manufacturers alike.

In this talk, we discuss how ubiquitous computing in the automotive domain can become a reality. We investigate the principal services resulting from network-connected cars, focussing on vehicle-originated rather than passenger-related communication as we believe that ubiquitous computing is more about communicating machines than communicating humans. Within the vehicle-centric services identified, we distinguish between client/server and peer-to-peer applications, resulting in different communication requirements and system setups. We outline some network solutions to meet these requirements, including technologies for car-to-infrastructure and car-to-car communication in different regions of the world. We conclude by discussing the overall effect which these developments may have on the automotive industry.

Labscape, a ubiquitous computing environment for cell biologists, was implemented twice: once using only standard tools for distributed systems (TCP sockets and shared file systems) and once using one.world, a runtime system designed specifically to support ubiquitous applications. We analyze Labscape in terms of the system properties that are required to provide a fluid user experience. Though the two implementations are functionally and architecturally similar, we found a significant difference in the degree to which they each exhibited the required properties. The fact that one.world was not designed specifically with Labscape in mind yet was found to support the application’s requirements well suggests that ubiquitous applications have many aspects in common, and can benefit from a system support layer for coping with dynamic environments. We present, in detail, the concepts embodied in one.world that we have found to be most important for Labscape, and how some of these concepts might be extended.

Information appliances, user interfaces, and context-aware devices are necessarily based on approximations of potential users and usage situations. However, it is not an unusual experience for developers that in some areas, appropriate approximations are extremely difficult to realize. Often, these difficulties are not apparent from the beginning. Nevertheless, difficulties are rarely addressed in the pervasive computing literature as they appear to be peripheral compared to the technical challenges. In this paper, we argue that the field would largely benefit from addressing these issues explicitly. First, focussed discussions would help identify areas that have already shown to be difficult or even intractable in related disciplines, such as AI or CSCW. Second, it would help developers become aware of the difficulties and would allow them to deliberately circumvent such areas. We use example scenarios from the pervasive computing literature to illustrate these points. Difficulties to describe and to analyze impacts of pervasive computing applications indicate a need for an analysis framework providing a specific terminology.

The need for an effective and adaptable data input method is fundamental to pervasive computing on hand held devices. The Fastap ™ keypad is a new paradigm of keyed input, providing more functionality in a smaller space than previously considered possible. Fastap technology may prove a useful advance to the widespread adoption of the mobile Internet, especially messaging, and more broadly to pervasive computing in general. The purpose of this white paper is to provide a framework for understanding the problems with existing mobile telephone interfaces, to introduce the Fastap technology and to qualify the assertion that the technology is a fundamental advance in keyed input that is well-suited as a replacement of the existing 12-button telephone interface.

This paper presents the lessons learnt from the development of a ubiquitous computing environment for use within the real world. Such systems are currently purpose built demonstrators, often within research labs. This paper is based on the development of a storytelling environment for use within schools. This migration - from the lab to the school - required the redevelopment of the platform, and highlighted the importance of providing support for the maintenance and management of the environment when access to a sophisticated infrastructure and dedicated space can no longer be guaranteed.

Multi-user communication and interaction via public displays together the pervasive and seamless access to the WWW in public areas via mobile phones or handheld devices is enabled via the WebWall system. A software framework for the operation of WebWalls has been developed, strictly separating WebWall access technologies (like HTTP, email, SMS, WAP, EMS, MMS or even simple paging protocols found on mobile phones) from the physical display technologies used and the presentation logic involved. The architecture integrates ubiquitous wireless networks (GSM, IEEE802.11b), allowing a vast community of mobile users to access the WWW via public communication displays in an ad-hoc mode. A centralized backend infrastructure hosting content posted by users in a display independent format has been developed together with rendering engines exploiting the particular features of the respective physical output devices installed in public areas like airports, trainstations, public buildings, lecture halls, fun and leisure centres and even car navigation systems. A variety of different modular service classes has been developed to support the posting or pulling of WWW media elements ranging from simple sticky notes, opinion polls, auctions, image and video galleries to mobile phone controlled web browsing.

Radio frequency identification systems with passive tags are powerful tools for object identification. However, if multiple tags are to be identified simultaneously, messages from the tags can collide and cancel each other out. Therefore, multiple read cycles have to be performed in order to achieve a high recognition rate. For a typical stochastic anti-collision scheme, we show how to determine the optimal number of read cycles to perform under a given assurance level determining the acceptable rate of missed tags. This yields an efficient procedure for object identification. We also present results on the performance of an implementation.

The use of computers in public places is increasingly common in everyday life. In using one of these computers, a user is trusting it to correctly carry out her orders. For many transactions, particularly banking operations, blind trust in a public terminal will not satisfy most users. In this paper the aim is therefore to provide the user with authenticated communication between herself and a remote trusted computer, via the untrusted computer.

After defining the authentication problem that is to be solved, this paper reduces it to a simpler problem. Solutions to the simpler problem are explored in which the user carries a trusted device with her. Finally, a description is given of two camera-based devices that are being developed.

Designing, implementing and evaluating prototypes is a normal way of doing technical research. In recent years we have seen lots of research prototypes specifically designed for context awareness, future user interfaces and intelligent environment research. The problem with this type of specialised prototypes is that their lifetime is rather short and the valuable work done for them is not easily reusable. Our approach has been different as we have deliberately aimed towards a multipurpose platform that would be suitable for various ubiquitous computing related research themes. In this article we present the design and implementation of the platform that is named as SoapBox (Sensing, Operating and Activating Peripheral Box). Its main features are wired and wireless communications, in-built sensors, small size and low power consumption. We also introduce some results of research projects that have already used the platform successfully. Finally we conclude the paper with application scenarios for further work.

A hardware and software platform has been designed and implemented for modeling, testing, and deploying distributed peer-to-peer sensor networks comprised of many identical nodes. Each node possesses the tangible affordances of a commonplace pushpin to meet ease-of-use and power considerations. The sensing, computational, and communication abilities of a “Pushpin”, as well as a “Pushpin” operating system supporting mobile computational processes are treated in detail. Example applications and future work are discussed.

While wireless sensor networks offer new capabilities, there are a number of issues that hinder their deployment in practice. We argue that robotics can solve or greatly reduce the impact of many of these issues. Our hypothesis has been tested in the context of an autonomous system to care for houseplants that we have deployed in our office environment. This paper describes what we believe is needed to make sensor networks practical, the role robots can play in accomplishing this, and the results we have obtained in developing our application.

As computing becomes more pervasive, the nature of applications must change accordingly. In particular, applications must become more flexible in order to respond to highly dynamic computing environments, and more autonomous, to reflect the growing ratio of applications to users and the corresponding decline in the attention a user can devote to each. That is, applications must become more context-aware. To facilitate the programming of such applications, infrastructure is required to gather, manage, and disseminate context information to applications. This paper is concerned with the development of appropriate context modeling concepts for pervasive computing, which can form the basis for such a context management infrastructure. This model overcomes problems associated with previous context models, including their lack of formality and generality, and also tackles issues such as wide variations in information quality, the existence of complex relationships amongst context information and temporal aspects of context.

Software configuration in a heterogeneous and dynamic environment such as ubiquitous computing is a challenging task. This paper presents the COCA model, which transforms heterogeneous ubiquitous computing resources through a process called classification into a conceptualized representation, which allows high-level manipulation and configuration by ubiquitous computing applications. A multi-modal ubiquitous computing application serves as a sample implementation of the model that uses an automatic software configuration process to dynamically adapt to changes in the environment.

The decreasing cost of computing technology is speeding the deployment of abundant ubiquitous computation and communication. With increasingly large and dynamic computing environments comes the challenge of scalable resource discovery, where client applications search for resources (services, devices, etc.) on the network by describing some attributes of what they are looking for. This is normally achieved through directory services (also called resolvers), which store resource information and resolve queries. This paper describes the design, implementation, and evaluation of INS/Twine, an approach to scalable intentional resource discovery, where resolvers collaborate as peers to distribute resource information and to resolve queries. Our system maps resources to resolvers by transforming descriptions into numeric keys in a manner that preserves their expressiveness, facilitates even data distribution and enables efficient query resolution. Additionally, INS/Twine handles resource and resolver dynamism by treating all data as soft-state.

A distributed real-time system, based on wearable accelerometers and magnetic sensors, is proposed for location estimation and recognition of walking behaviors. Suitable for both outdoor and indoor navigation, the system is especially adjusted for irregular movements indoors. The algorithm, which demands only small computing resources, performs step detection and classification in the time domain, allowing the estimation of the size of each separate step independently. Since the system finds the user’s position relative to an initial position, it is intended to be supplemented with different types of absolute positioning information. Making use of map knowledge, as an easily available source of this information, is analyzed. The conclusion is drawn that referring to the locations of the corridors and stairways increases the positioning accuracy and reduces the effect of magnetic field distortions encountered inside buildings. The positioning error of different system configurations was 3-10 % from traveled distance.

With the increasing popularity of mobile computing devices, the need to access information in mobile environments has also grown rapidly. In order to support such mobile information accesses, location-based services and mobile information systems often rely on location-aware data management mechanisms like location-aware caching, data dissemination or prefetching. As we explain in this paper, the location-awareness of such mechanisms is only useful, if the accessed information is location-dependent, i.e. if the probability with that a certain information object is accessed depends on the user’s location.

Although the location-dependency of the accessed information is crucial for the efficiency of location-aware data management mechanisms and the benefit they can get out of their location-awareness, no metric to measure the location-dependency of information has been proposed so far. In this paper, we describe such a metric together with a second one for a further important characteristic of mobile information accesses, the so-called focus.

We have developed a communication support system that estimates the situation of a person using schedule information and location information provided by a PHS (Personal Handy Phone System). From the lessons provided by our prior studies and inventions, we developed a new mobile communication tool for cellular phones that uses location information and schedule information. This is a kind of dynamic telephone book, which we have named iCAMS. We performed user studies for eight weeks in Tokyo with a group of students and with a group of small-office workers. By analyzing the communication logs, questionnaires and interviews we conducted with the users, we evaluated our system.

We introduce browser state repository (BSR) service that allows a user to save and restore multiple independent snapshots of web sessions on a browser. At a later time, the user can retrieve any saved snapshot on a potentially different browser on a different device to continue any one of the chosen saved session in any order. The web session snapshot captures a complete browser running state, including the last page that appears on the browser, document object state, script state, values that a user enters in forms on the last page, browser history for back and forward pages, and cookies. BSR service consists of a browser plug-in that takes browser session snapshots, and a repository server that stores snapshots securely for each user. The main contribution of BSR service is that it decouples association between browser state and a device, in favor of association between browser state and its user.

Users are increasingly accessing the Internet from mobile devices as well as conventional desktop computers. However, it is not reasonable to expect content authors to create different data presentations for each device type, but the content source should be reused across multiple delivery contexts whenever possible. The objective of this research is to develop a supporting tool for the presentation customization that follows after the content specialization in device-independent authoring. This paper presents a tool that automatically generates content customization metadata on the basis of users’ editing operations toward the desired results of the customization. A prototype of the metadata generator was developed for the generation of page-clipping annotations to be used for an annotation-based transcoding system.