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Absolutely nothing!? The merit of theory and algorithms in the context of wireless sensor and ad hoc networks is often questioned. Admittedly, coming up with theory success stories that will be accepted by practitioners is not easy. In my talk I will discuss the current score of the Theory vs. Practice game, after playing seven years for the Theory team. Probably due to a “seven year itch”, I recently...
In a bipartite max-min LP, we are given a bipartite graph $\mathcal{G} = (V \cup I \cup K, E)$ , where each agent v ∈ V is adjacent to exactly one constraint i ∈ I and exactly one objective k ∈ K. Each agent v controls a variable xv. For each i ∈ I we have a nonnegative linear constraint on the variables of adjacent agents. For each k ∈ K we have a nonnegative...
Building on previous work [Bonifaci et al., Minimizing flow time in the wireless gathering problem, STACS 2008] we study data gathering in a wireless network through multi-hop communication with the objective to minimize the average flow time of a data packet. We show that for any the problem is NP-hard to approximate within a factor better than , where m is the number of data packets. On...
We consider the problem of counting a set of discrete point targets using a network of sensors under a minimalistic model. Each sensor outputs a single integer, the number of distinct targets in its range, but targets are otherwise indistinguishable to sensors: no angles, distances, coordinates, or other target-identifying measurements are available. This minimalistic model serves to explore the fundamental...
Many applications in sensor networks demand for energy and time optimal routing of data towards a sink. In this work we present mechanisms to set up energy and time efficient TDMA schedules for a given routing tree under very strict limitations: Nodes have only a constant size memory and must agree on a schedule using only a minimum of communication for set up: Each node is only allowed to send a...
Choosing an appropriate interference model is crucial for link scheduling problems in sensor networks. While graph-based interference models allow for distributed and purely local coloring approaches which lead to many interesting results, a more realistic and widely agreed on model such as the signal-to-noise-plus-interference ratio (SINR) inherently makes scheduling radio transmission a non-local...
In this paper, we re-examine the RSSI measurement model for location estimation and provide the first detailed formulation of the probability distribution of the position of a sensor node. We also show how to use this probabilistic model to efficiently compute a good estimation of the position of the sensor node by sampling multiple readings from the beacons (where we do not merely use the mean of...
We concern security of shrinking generator against fault attacks. While this pseudorandom bitstream generator is cryptographically strong and well suited for hardware implementations, especially for cheap artefacts, we show that using it for the devices that are not fault resistant is risky. That is, even if a device concerned is tamper-proof, generating random faults and analyzing the results may...
In this work we present three new distributed, probabilistic data propagation protocols for Wireless Sensor Networks which aim at maximizing the network’s operational life and improve its performance. The keystone of these protocols’ design is fairness which declares that fair portions of network’s work load should be assigned to each node, depending on their role in the system. All the three protocols,...
With the current progress in robot technology and related areas, sophisticated moving and sensing capabilities are at hand to design robots capable of solving seemingly complex tasks. With the aim of understanding the limitations of such capabilities, swarms of simple and cheap robots play an increasingly important role. Their advantages are, among others, the cost, reusability, and fault-tolerance...
We consider the problem of uniformly dispersing mobile robotic sensors in a simply connected orthogonal space of unknown shape. The mobile sensors are injected into the space from one or more entry points and rely only on sensed local information within a restricted radius. Unlike the existing solution, we allow the sensors to be asynchronous and show how, even in this case, the sensors can uniformly...
Suppose that a cup is installed at every point of a planar set P, and that somebody pours water into the cups. The total rate at which the water flows into the cups is 1. A player moves in the plane with unit speed, emptying the cups. At any time, the player sees how much water there is in every cup. The player has no information on how the water will be poured into the cups in the future; in particular,...
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