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A task management system that automatically optimizes the schedule of a person by context-aware interleaving of activities can enable persons to be involved more efficiently in daily activities of interests. As a technical basis for such a task management system, we propose the activity broker architecture. The core of this architecture is formed by the activity scheduler that can effectively schedule...
Mobile ad-hoc networks have long been proposed for rescue scenarios to support and coordinate the efforts of helpers. Low power wireless sensor networks are a natural extension of this approach. They can provide valuable environmental data enriched with location information to deepen the insight of the operational area. Gateways between these two communication paradigms are necessary to facilitate...
The availability of secret keys is a precondition for the use of many security solutions and protocols. However, securely assigning such keys to nodes is a challenging task in the context of wireless sensor networks. In this paper we present a novel solution for a secure key assignment in wireless sensor networks that can be used during the initial configuration of nodes or for an ad-hoc key assignment...
The Cooperating Objects NETwork of Excellence (CONET) aims at building a strong community in the area of Cooperating Objects capable of conducting the needed research to achieve, in the long run, the vision of Mark Weiser for ubiquitous computing. For this purpose, research clusters have been instantiated covering, among other topics, scalable data processing, cooperation of mobile objects, simulations...
The ability to update or exchange the program code running on sensor nodes is a core requirement in many wireless sensor network scenarios. Such code update mechanisms must take the specific resource limitations of wireless sensor nodes into account since both the transmission and the processing of updates consume considerable amounts of time and energy. We present TinyModules, a novel code update...
Pervasive computing envisions distraction-free support for user tasks by means of cooperating devices that are invisibly integrated into the environment. Due to device mobility and continuous changes in context, pervasive systems need to be adaptive to realize this vision. To simplify their development, pervasive computing middleware ease the resulting configuration tasks. In the past, middleware...
Wireless sensor networks play an essential role in many pervasive computing scenarios as providers of context data. However, interacting with sensor nodes and selecting specific nodes for an interaction is difficult due to the constraints of the sensor node hardware. In this paper, we present and discuss three different approaches for this node interaction problem based on gestures, on light signals...
The lifetime requirements on wireless sensor networks often require the redundant deployment of sensor nodes with appropriate management mechanisms based on node clustering. Yet, existing clustering approaches do not take the primary task of sensor networks into account: performing relevant measurements. They usually form 'arbitrary' clusters, e.g., using connectivity information, and thus, the resulting...
Boundary recognition is an important and challenging issue in wireless sensor networks when no coordinates or distances are available. The distinction between inner and boundary nodes of the network can provide valuable knowledge to a broad spectrum of algorithms. This paper tackles the challenge of providing a scalable and range-free solution for boundary recognition that does not require a high...
The fundamental paradigm of context-aware computing has lead to a diversity of conceivable context-based applications. In order to support these applications, efficient and scalable context management platforms have become utterly important. In this paper we propose a layered reference model that encapsulates suitable abstractions to tackle the complexity of context management in mobile ad-hoc networks...
Wireless sensor networks can monitor different types of physical phenomena and are able to provide a diverse set of context data to interested clients. Allowing mobile pervasive computing devices to access such data requires solutions for routing messages between mobile devices and the static sensor network. This paper presents a novel approach that addresses this problem with the help of symbolic...
This paper presents the AWARE platform that seeks to enable the cooperation of autonomous aerial vehicles with ground wireless sensor-actuator networks comprising both static and mobile nodes carried by vehicles or people. Particularly, the paper presents the middleware, the wireless sensor network, the node deployment by means of an autonomous helicopter, and the surveillance and tracking functionalities...
The performance of distributed algorithms in mobile ad hoc networks is strongly influenced by the connectivity of the network. In cases where the connectivity is low, network partitioning occurs. The mobility and the density of network nodes as well as the communication technology are fundamental properties that have a large impact on partitioning. A detailed characterization of this behavior helps...
In the process of observing changes in our surroundings, the chronological ordering of these observations plays a crucial role. The same holds for many applications that employ sensors to gather information about their physical environment in order to adapt to changes. In this paper, we present a data replication algorithm for mobile ad hoc and sensor networks that guarantees chronological ordering...
With the proliferation of wireless communication and sensor technology, the importance of location-based applications has tremendously increased. In order to support these applications, services that implement algorithms for the efficient processing of spatial queries, such as range and k-nearest neighbor queries, are definitely beneficial. In this paper, we propose definitions of probabilistic range...
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