Uwe Kubach

Next century challenges: Nexus—an open global infrastructure for spatial-aware applications

Due to the lack of a generic platform for locationand spatial-aware systems, many basic services have to be reimplemented in each application that uses spatial-awareness. A cooperation among different applications is also difficult to achieve without a common platform. In this paper we present a platform that solves these problems. It provides an infrastructure that is based on digital models of regions of the physical world, which are augmented by virtual objects. We show how virtual objects make the integration of existing information systems and services in spatial-aware systems easier. Furthermore, our platform supports interactions between the computer models and the real world and integrates single models in a global “Augmented World”.

Exploiting location information for infostation-based hoarding

With the increasing popularity of mobile computing devices, the need to access information in mobile environments has grown rapidly. Since the information has to be accessed over wireless networks, mobile information systems often have to deal with problems like low bandwidth, high delay, and frequent disconnections. Information hoarding is a method that tries to overcome these problems by transferring information, which the user will probably need, in advance. The hoarding mechanism that we describe in this paper exploits the location dependence of the information access, which is often found in mobile information systems. Our simulation results show that it is beneficial to do so and that we achieve higher hit ratios than with a caching mechanism.

eSeal – A System for Enhanced Electronic Assertion of Authenticity and Integrity

Ensuring authenticity and integrity are important tasks when dealing with goods. While in the past seal wax was used to ensure the integrity, electronic devices are now able to take over this functionality and provide better, more fine grained, more automated and more secure supervision. This paper presents eSeal, a system with a computational device at its core that can be attached to a good, services in the network and a communication protocol. The system is able to control various kinds of integrity settings and to notify authenticated instances about consequent violations of integrity. The system works without infrastructure so that goods can be supervised that are only accessible in certain locations. The paper motivates the eSeal system and its design decisions, lists several types of integrity scenarios, presents the communication protocol and identifies practical conditions for design and implementation. An implementation in a business relevant scenario is presented as a proof of concept.

DigiClip: activating physical documents

Today many documents are held in parallel as electronic files and as paper based documents. Keeping the properties of both versions in sync is important to assure consistency between the physical and virtual instances of one document. We introduce the DigiClip system that provides a solution to automatically enforce such consistency by converting passive paper documents to active physical documents. The main component of the system is the DigiClip device, a clip with embedded computing, sensing and communication technology that is attached to a paper document. The device is able to supervise the status of the document and to communicate to a software component that supervises the electronic instance of the same document. In this way the DigiClip system enables applications to automatically coordinate properties like integrity and access restrictions and to keep track of changes both of the physical and the virtual document.

An adaptive, location-aware hoarding mechanism

When used in an outdoor environment mobile information systems often suffer from the disadvantages of wireless WANs. Hoarding is a method to overcome these disadvantages by transferring information which is probably needed by the user in advance. Existing hoarding mechanisms are either developed for a certain type of application or do not consider the users location when selecting the information items to hoard. However, exploiting location information can be of great benefit with respect to the achievable hit-ratios. The hoarding mechanism suggested in this paper is both location-aware and universally applicable. Therefore, it can be used as a generic mechanism in a platform which supports different kinds of mobile information systems. In addition, it can be adapted to different degrees of knowledge about the users movement.

A Map-Based Hoarding Mechanism for Location-Dependent Information

In mobile environments, information systems are often accessed through wireless WANs. Thus the users often have to cope with difficulties such as low bandwidth, high delay, and frequent disconnections. Hoarding is an efficient method to overcome these difficulties. The idea is to transfer information, which is probably needed by the user in the near future, in advance, so that it is already stored on the users mobile device when it is actually accessed. In this paper, we present a location-aware hoarding mechanism that is based on the use of wireless LANs, so-called info-stations. Due to its flexibility, we claim that our mechanism can be applied in any location-dependent information system.

Estimating the Benefit of Location-Awareness for Mobile Data Management Mechanisms

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 users 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.

Collaborative control and coordination of hazardous chemicals

General Terms Algorithms, management.

Metaphors and Context-Aware Information Access

Abstract: Metaphors are often used to provide the user with a mental model to ease the use of computers. An example of such a metaphor is the commonly used “Desktop Metaphor”. Metaphors also can be used to ease context-aware information access for the users of mobile information systems. In this paper we present a taxonomy that allows the categorisation of such metaphors. Furthermore, we give an overview of existing metaphors and their implementations. After introducing some new metaphors we conclude our considerations with a classification of new and existing metaphors using our taxonomy.

A Universal, Location-Aware Hoarding Mechanism

Hoarding is an often used technique to overcome the disadvantages of wireless wide area communication. The basic idea of hoarding is to transfer information to a mobile device before it is actually accessed on the device. The main problem is to decide which information will be needed on the devices. We propose a hoarding mechanism which exploits the fact that the information a user accesses depends on his/her geographic location.