Scientific publications

In this paper we address the problem of sink placement for Gossip-based Wireless Sensor Networks (GWSN). Sink placement plays an important role in planning and deployment of sensor networks. It is an efficient means to improve performance and achieve design objectives. Sink deployment requires an optimization strategy to search a space of possible placement options, and a performance evaluation method to assess the quality of different sink placements.

This chapter reflects on Falcon, a project to advance automation inwarehouses. Its main results and their impact as well as the project’s process arediscussed. The impact of Falcon on its industrial partners mainly concern model-based methods, of which strengthening the inception of the new architecture forsystem-level control of warehouses is a good example.

The warehouses of the future will come in a variety of forms, but with a few common ingredients. Firstly, human operational handling of items in warehouses is increasingly being replaced by automated item handling. Extended warehouse automation counteracts the scarcity of human operators and supports the quality of picking processes.

Architectural stress is the inability of a system design to respond to new market demands. It is an important yet often concealed issue in high tech systems. In From scientific instrument to industrial machine, we look at the phenomenon of architectural stress in embedded systems in the context of a transmission electron microscope system built by FEI Company.

The inherently unreliable communication infrastructure compel WSN protocols to employ error control mechanisms. Traditionally, error control is achieved by a retransmission scheme using acknowledgment mechanisms. WSN architectures are severely resource constrained and the additional energy expense of transmitting error control messages can seriously degrade network lifetime.

Wireless Body Area Networks (WBANs) have characteristic properties that should be considered for designing a proper network architecture. Movement of on-body sensors, low quality and time-variant wireless links, and the demand for a reliable and fast data transmission at low energy cost are some challenging issues in WBANs.

Warehouses play a critical role in supply chains: they are responsible for the distribution of goods of many suppliers to many customers. Because of increasing customer demands, warehouse processes are becoming too complex to be controlled optimally by their traditional centralised control systems. Several results in the literature show that decentralised controllers are a viable alternative.

Peer-to-peer botnets, as exemplified by the Storm Worm, and the spreading phase of Stuxnet, are a relatively new threat to security on the internet: infected computers automatically search for other computers to be infected, thus spreading the infection rapidly. In a recent paper, such botnets have been modeled using Stochastic Activity Networks, allowing the use of discrete-event simulation to judge strategies for combating their spread.

The quality of the communication links in a Wireless Sensor Network often shows significant asymmetry and variation over time, due to, for example, heterogeneous settings of the transmission power, moving nodes or chang- ing external interference. This makes it difficult for nodes to accurately maintain system-level properties, such as the minimum-energy path from the node to a given reference node, as required by many protocols.