Konrad Iwanicki

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Much research on content-based P2P searching for file-sharing applications has focused on exploiting semantic relations between peers to facilitate searching. Current methods suggest reactive ways to manage semantic relations: they rely on the usage of the underlying search mechanism, and infer semantic relationships based on the queries placed and the(More)
Hierarchical routing is a promising approach for point-to-point routing with very small routing state. While there are many theoretical analyses and high-level simulations demonstrating its benefits, there has been little work to evaluate it in a realistic wireless sensor network setting. Based on numerous proposed hierarchical routing infrastructures, we(More)
Numerous large-scale decentralized systems assume loosely synchronized clocks. Existing time protocols have not been designed for deployment in such systems, since they are complex and require manual configuration. We present the Gossiping Time Protocol (GTP), a completely self-managing epidemic time synchronization algorithm for peer-to-peer networks. In(More)
Time synchronization between computers within a very large, highly dynamic network is a challenging task. Current solutions operate mostly in a hierarchical client-server mode based on a static configuration of logical connections, which tends to lack the scalability and robustness to failures. In this thesis, the author presents the Gossiping Time Protocol(More)
We introduce our 60-node indoor wireless sensor network testbed, distributed among six office rooms. We outline the hardware architecture of the testbed and discuss the basic properties of the internode connectivity graph. In particular, we show that a node in the testbed has from 8 to 31 high-quality neighbors and that the network diameter is between 4 and(More)
Many recently proposed sensornet applications require large number of sensor nodes operating over long periods of time. In contrast to the first-generation sensornet deployments, these applications involve sophisticated internode communication rather than simple tree-based data collection. The examples include network maintenance, data-centric storage,(More)
Multi-hop cluster hierarchy has been presented as an organization for large wireless sensor networks (WSNs) that can provide scalable routing, data aggregation, and querying. In this paper, we revisit the fundamental problem of maintenance of such a hierarchy. To this end, we observe that, due to tightly coupling their operation with the topology of the(More)
A recursive multihop area hierarchy has a number of applications in wireless sensor networks, the most common being scalable point-to-point routing, so-called hierarchical routing. In this paper, we consider the problem of maintaining a recursive multihop area hierarchy in large sensor networks. We present a gossip-based protocol, dubbed PL-Gossip, in which(More)
We focus on a popular message dissemination protocol for wireless ad-hoc networks, Gossip3. Our contribution is twofold. First, we perform an extensive experimental evaluation of Gossip3 under fully utilized wireless channel and across diverse node densities. We identify the parameters of Gossip3 that need special configuration for the protocol to operate(More)
In this position paper, we address the issue of durable maintenance of a wireless sensor network, which will be crucial if the vision of large, long-lived sensornets is to become reality. Durable maintenance requires tools for diagnosing and fixing occurring problems, which can range from internode connectivity losses, to time synchronization problems, to(More)