Stripping und Analytik von Methan aus natuerlichen Waessern

TIB Hannover: DR 6053 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Efficient reprogramming of sensor networks using incremental updates and data compression

Reprogramming is an important issue in wireless sensor networks. It enables users to extend or correct functionality of a sensor network after deployment, at a low cost. In this paper, we investigate two problems: improving the energy efficiency and improving the delay of reprogramming. As enabling technologies we use data compression and incremental updates. We analyze different algorithms for both approaches, as well as their combination, when applied to resource-constrained devices. All algorithms are ported to the Contiki embedded operating system, and profiled for different types of reprogramming. Our results show that there is a clear trade-off between performance and resource requirements. Either VCDIFF, or the combination of Lempel-Ziv-77 or FastLZ compression algorithms with BSDIFF for delta encoding, have the best overall performance compared to other compression algorithms

Context based service discovery in unmanaged networks using MDNS/DNS-SD

We propose an extension of the mDNS/DNS-SD service discovery protocol, which enables service clients to discover and select services based on their context. The extension improves scalability in large networks, which is of particular importance in future Internet of Things deployments

Improving the performance of trickle-based data dissemination in low-power networks

Trickle is a polite gossip algorithm for managing communication traffic. It is of particular interest in low-power wireless networks for reducing the amount of control traffic, as in routing protocols (RPL), or reducing network congestion, as in multicast protocols (MPL). Trickle is used at the network or application level, and relies on up-to-date information on the activity of neighbors. This makes it vulnerable to interference from the media access control layer, which we explore in this paper. We present several scenarios how the MAC layer in low-power radios violates Trickle timing. As a case study, we analyze the impact of CSMA/CA with ContikiMAC on Trickle’s performance. Additionally, we propose a solution called Cleansing that resolves these issues