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Koch A.,armasuisse | Bianchi S.,RUAG Land Systems AG
25th International Symposium on Ballistics, ISB 2010 | Year: 2010

Steel is the most used material for the confinement plates of explosive reactive armours, but other materials afford better protection against shaped charges. One of the most interesting material is ceramic because of its hardness, of its relatively small density and of the reduction of collateral damages. We have therefore compared the protection efficiency of reactive armours built either with steel or with alumina plates. We varied both the weight of the confinement plates and the thickness of the explosive sheet. For each configuration, we measured the protection efficiency against a standard shaped charge. Clear correlations arc observed between the weight of the confinement plates or the amount of contained explosive, on the one hand, and the protection efficiency of the reactive armour, on the other hand.

Heinzer P.,ETH Zurich | Lenders V.,armasuisse | Legendre F.,ETH Zurich
Proceedings - IEEE INFOCOM | Year: 2012

Fast and accurate link quality estimation is an important feature for wireless protocols such as routing, rate switching or handover. Existing signal strength based estimators tend to be fast but inaccurate while packet statistic based approaches are more accurate but require longer estimation times. We propose a new link quality estimation approach based on chip errors in symbols for direct sequence spread spectrum transceivers. The new link quality estimator is evaluated experimentally with software defined radios on IEEE 802.15.4 for different link conditions, including multi-path and mobile scenarios. We show that our chip error based link quality estimator performs more accurately than received signal strength based estimators and much faster than the packet statistic based estimators with comparable accuracy. With our approach, only a single packet, or even a fraction of a packet (e.g., only a few symbols), is necessary to obtain similar performance as state-of-the-art approaches that require at least 10 packets. © 2012 IEEE.

Lenders V.,armasuisse
2013 Workshop on Sensor Data Fusion: Trends, Solutions, Applications, SDF 2013 | Year: 2013

Conventional Web search models are ineffective at providing quick and comprehensive answers to questions related to live content such as real-time data or temporal relationships between actors. Semantic data fusion techniques have the potential to provide a more suitable abstraction model for efficient search on this type of data. However, myriad architectural and technical implementation challenges arise when trying to implement a working system. This paper summarizes our efforts and experiences at implementing a functional semantic fusion system for live content from the Web. Besides semantic data fusion techniques, we make extensive use of natural language processing, semantic Web technologies and Bayesian statistics to render the system a self-contained framework acting directly between Web resources of interest and end-user search applications. We first present the semantic fusion architecture design that we have developed. We have implemented this architecture and tested its effectiveness using real-world live data from the Web over multiple weeks. We then report about our major experiences and lessons-learned of this experiment. © 2013 IEEE.

Gugelmann D.,ETH Zurich | Schatzmann D.,ETH Zurich | Lenders V.,armasuisse
ASIA CCS 2013 - Proceedings of the 8th ACM SIGSAC Symposium on Information, Computer and Communications Security | Year: 2013

This paper presents Horizon Extender, a system for long-term preservation of data leakage evidence in enterprise networks. In contrast to classical network intrusion detection systems that keep only packet records of suspicious traffic (black-listing), Horizon Extender reduces the total size of captured network traces by filtering out all records that do not reveal potential evidence about leaked data (white-listing). Horizon Extender has been designed to exploit the inherent redundancy and adherence to protocol specification of general Web traffic. We show in a real-life network including more than 1000 active hosts that Horizon Extender is able to reduce the total HTTP volume by 99.8%, or the outgoing volume by 90.9% to 93.9%, while preserving sufficient evidence to recover retrospectively time, end point identity, and content of information leaked over the HTTP communication channel. © 2013 ACM.

Wilhelm M.,University of Kaiserslautern | Martinovic I.,University of Kaiserslautern | Schmitt J.B.,University of Kaiserslautern | Lenders V.,armasuisse
WiSec'11 - Proceedings of the 4th ACM Conference on Wireless Network Security | Year: 2011

In this work, we take on the role of a wireless adversary and investigate one of its most powerful tools - radio frequency jamming. Although different jammer designs are discussed in the literature, reactive jamming, i.e., targeting only packets that are already on the air, is generally recognized as a stepping stone in implementing optimal jamming strategies. The reason is that, while destroying only selected packets, the adversary minimizes its risk of being detected. One might hope for reactive jamming to be too challenging or uneconomical for an attacker to conceive and implement due to its strict real-time requirements. Yet, in this work we disillusion from such hopes as we demonstrate that flexible and reliable software-defined reactive jamming is feasible by designing and implementing a reactive jammer against IEEE 802.15.4 networks. First, we identify the causes of loss at the physical layer of 802.15.4 and show how to achieve the best performance for reactive jamming. Then, we apply these insights to our USRP2-based reactive jamming prototype, enabling a classification of transmissions in real-time, and reliable and selective jamming. The prototype achieves a reaction time in the order of microseconds, a high precision (such as targeting individual symbols), and a 97.6 % jamming rate in realistic indoor scenarios for a single reactive jammer, and over 99.9 % for two concurrent jammers. Copyright © 2011 ACM.

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