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Given a set of commodities and a network where some arcs can fail while others are reliable, we first consider the problem of computing a minimum-cost pair of paths not sharing failing links. If a reliable link belongs to both paths then its cost is counted only once. We show that this problem can be solved in strongly polynomial time. Second, we consider a routing problem where each commodity can
In this technical report, we consider ultra light-weight constructions of message authentication in hardware applications. We examine several known constructions and evaluate details around their hardware implementations. These constructions are all based on the framework of universal hash functions.
This paper presents a method based on the phase dierence of arrival and the non-linear least square estimation to lo- calize a radio-frequency (RF) source, e.g a wireless capsule endoscope, inside the human body. The phase dierence of arrival at multiple frequencies of a signal is used to estimate the distance of the source to a receiver. The linear least square estimation is used to estimate the
The paper investigates advantages of using an MCCA-aware acknowledging system in IEEE 802.11s Wireless Mesh Networks (WMN). The MCCA (MCF controlled channel access) protocol allows for reserving time slots for a point-topoint transmission over a wireless link. The protocol assures that the transmission will not be hindered by any other 802.11 device that uses MCCA, by preventing all neighbors of b
Shadowing from vehicles can degrade the performance of vehicle-to-vehicle (V2V) communication systems significantly. It is thus important to characterize and model the influence of common shadowing objects like cars properly. For multilink systems it is essential to model the joint effects on the different links. However, the multilink shadowing effects in V2V channels are not yet well understood.
This paper presents an architecture of an auto-correlator for Orthogonal Frequency Division Multiplexing systems. The received signal is quantized to only the sign-bit, which dramatically simplifies the frequency offset estimation. Hardware cost is reduced under the assumption that synchronization during acquisition does not have to be very accurate, but sufficient for coarse estimation. The archi
The pathloss exponent and the variance of the large-scale fading are two parameters that are of great importance when modeling or characterizing wireless propagation channels. The pathloss is typically modeled using a single-slope log-distance power law model, whereas the large-scale fading is modeled using a log-normal distribution. In practice, the received signal is affected by noise and it mig
We consider a class of weak feedback polynomials for LFSRs in the nonlinear combiner. When feedback taps are located in small groups, a distinguishing attack can sometimes be improved considerably, compared to the common attack that uses low weight multiples. This class of weak polynomials was introduced in 2004 and the main property of the attack is that the noise variables are represented as vec
At the same time as our dependence on IT systems increases, the number of reports of problems caused by failures of critical IT systems has also increased. Today almost every system or service, e.g., water, power supply, transportation, is dependent on IT systems, and failure of these systems has serious and negative effects on society. In general, governmental organizations are responsible for de
