Deterministic Secure Positioning in Wireless Sensor Networks

Properly locating sensor nodes is an important building block for a large subset of wireless sensor networks (WSN) applications. As a result, the performance of the WSN degrades significantly when misbehaving nodes report false location and distance information in order to fake their actual location. In this paper we propose a general distributed deterministic protocol for accurate identification of faking sensors in a WSN. Our scheme does \emph{not} rely on a subset of \emph{trusted} nodes that are not allowed to misbehave and are known to every node in the network. Thus, any subset of nodes is allowed to try faking its position. As in previous approaches, our protocol is based on distance evaluation techniques developed for WSN. On the positive side, we show that when the received signal strength (RSS) technique is used, our protocol handles at most $\lfloor \frac{n}{2} \rfloor-2$ faking sensors. Also, when the time of flight (ToF) technique is used, our protocol manages at most $\lfloor \frac{n}{2} \rfloor - 3$ misbehaving sensors. On the negative side, we prove that no deterministic protocol can identify faking sensors if their number is $\lceil \frac{n}{2}\rceil -1$. Thus our scheme is almost optimal with respect to the number of faking sensors. We discuss application of our technique in the trusted sensor model. More precisely our results can be used to minimize the number of trusted sensors that are needed to defeat faking ones

Deterministic Secure Positioning in Wireless Sensor Networks

Properly locating sensor nodes is an important building block for a large subset of wireless sensor networks (WSN) applications. As a result, the performance of the WSN degrades significantly when misbehaving nodes report false location and distance information in order to fake their actual location. In this paper we propose a general distributed deterministic protocol for accurate identification of faking sensors in a WSN. Our scheme does \emph{not} rely on a subset of \emph{trusted} nodes that are not allowed to misbehave and are known to every node in the network. Thus, any subset of nodes is allowed to try faking its position. As in previous approaches, our protocol is based on distance evaluation techniques developed for WSN. On the positive side, we show that when the received signal strength (RSS) technique is used, our protocol handles at most $\lfloor \frac{n}{2} \rfloor-2$ faking sensors. Also, when the time of flight (ToF) technique is used, our protocol manages at most $\lfloor \frac{n}{2} \rfloor - 3$ misbehaving sensors. On the negative side, we prove that no deterministic protocol can identify faking sensors if their number is $\lceil \frac{n}{2}\rceil -1$. Thus our scheme is almost optimal with respect to the number of faking sensors. We discuss application of our technique in the trusted sensor model. More precisely our results can be used to minimize the number of trusted sensors that are needed to defeat faking ones

Packet latency of deterministic broadcasting in adversarial multiple access channels

We study broadcasting in multiple access channels with dynamic packet arrivals and jamming. Communication environments are represented by adversarial models that specify constraints on packet arrivals and jamming. We consider deterministic distributed broadcast algorithms and give upper bounds on the worst-case packet latency and the number of queued packets in relation to the parameters defining adversaries. Packet arrivals are determined by a rate of injections and a number of packets that can be generated in one round. Jamming is constrained by a rate with which an adversary can jam rounds and by a number of consecutive rounds that can be jammed

WIND LOADS’ INFLUENCE ON THE HIGH-RISE BUILDING OF AN IRREGULAR FORM – MODEL STUDIES

W referacie nawiązano do przeprowadzonych analiz oddziaływania wiatru na wieżowiec o nieregularnym rzucie i wysokości nieprzekraczającej 200 m. Celem badawczym było porównanie przyjmowanych normowych wartości obciążeń wiatrem, w stosunku do wartości uzyskanych w badaniach modelowych. Porównanie przeprowadzono w zakresie ciśnień szczytowych wiatru działających na fasady oraz sił wypadkowych działających na konstrukcję budynku. Zasadnicze różnice wynikały z braku uwzględnienia wpływu sąsiedniej zabudowy w obliczeniach wg PN-EN. Wypadkowe siły powstałe po scałkowaniu pomierzonych doświadczalnie ciśnień były znacznie mniejsze niż siły założone zgodnie z PN EN. Można stwierdzić, że wyniki uzyskane z badań doświadczalnych, jako opracowania bardziej miarodajne, mogą stanowić podstawę do przyjmowania mniejszych wartości obciążeń.In the paper there is reference to the analysis of wind influence on the skyscraper of an irregular plan and the height not exceeding 200 metres. The aim of the research was the comparison of wind load values based on eurocodes in relation to the results of experimental research carried out in an aerodynamic tunnel. The comparison concerned wind spike pressure influencing the facades of the building and resultant forces acting on its structure. The major differences of force values calculated in accordance with euro codes and these obtained from experimental research resulted from not taking into account the influence of neighbouring buildings in calculations based on PN-EN. The resultant forces arising from the integration of experimentally measured pressure were significantly smaller than those calculated in accordance with PN-EN. To conclude, one might state that the results obtained from experimental research - as more reliable ones - could be the basis for assuming smaller wind loads

Adversarial queuing on the multiple-access channel

We consider broadcasting on the multiple-access channel when packets are injected continuously. Multiple-access channel is a synchronous system with the properties that a single transmission at a round delivers the message to all nodes, while multiple simultaneous transmissions result in a conflict which prevents delivering messages to any among the recipients. The traditional approach to dynamic broadcasting has been concerned with stability of protocols under suitable stochastic assumptions about injection rates. We study deterministic protocols competing against adversaries restricted by injection rate and burstiness of traffic. Stability means that the number of packets in queues is bounded by a constant in any execution, for a given number of stations, protocol, and adversary. Strong stability denotes th