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In an effort to secure the northern and southern United States borders, MITRE has been tasked with developing Modeling and Simulation (M&S) tools that accurately capture the mapping between algorithm-level Measures of Performance (MOP) and system-level Measures of Effectiveness (MOE) for current/future surveillance systems deployed by the Customs and Border Protection Office of Technology Innovations and Acquisitions (TIA). This analysis is part of a larger M&S undertaking. The focus is on two MOPs for magnetometer-based Unattended Ground Sensors (UGS) placed near roads to detect passing vehicles and estimate properties of the vehicle's trajectory such as bearing and speed. The first MOP considered is the probability of detection. We derive probabilities of detection for a network of sensors over an arbitrary number of observation periods and explore how the probability of detection changes when multiple sensors are employed. The performance of UGS is also evaluated based on the level of variance in the estimation of trajectory parameters. We derive the Cramr-Rao bounds for the variances of the estimated parameters in two cases: when no a priori information is known and when the parameters are assumed to be Gaussian with known variances. Sample results show that UGS perform significantly better in the latter case., sponsored by NSA.

The European Space Agency's Rosetta spacecraft, en route to a 2014 encounter with comet 67P/Churyumov-Gerasimenko, made a gravity assist swing-by of Mars on 25 February 2007, closest approach being at 01:54UT. The Alice instrument on board Rosetta, a lightweight far-ultraviolet imaging spectrograph optimized for in situ cometary spectroscopy in the 750-2000 A spectral band, was used to study the daytime Mars upper atmosphere including emissions from exospheric hydrogen and oxygen. Offset pointing, obtained five hours before closest approach, enabled us to detect and map the HI Lyman-alpha and Lyman-beta emissions from exospheric hydrogen out beyond 30,000 km from the planet's center. These data are fit with a Chamberlain exospheric model from which we derive the hydrogen density at the 200 km exobase and the H escape flux. The results are comparable to those found from the the Ultraviolet Spectrometer experiment on the Mariner 6 and 7 fly-bys of Mars in 1969. Atomic oxygen emission at 1304 A is detected at altitudes of 400 to 1000 km above the limb during limb scans shortly after closest approach. However, the derived oxygen scale height is not consistent with recent models of oxygen escape based on the production of suprathermal oxygen atoms by the dissociative recombination of O2+., Comment: 17 pages, 8 figures, accepted for publication in Icarus

In this article, it is posited that we are not, contrary to conventional wisdom, living in “post-imperial” times; on the contrary, it is suggested that we inhabit a re-imperialized terrain in the sense that imperial reason has been re-asserted, as clearly evident, for example, in the invasions of Iraq and Afghanistan —interventions that express a Western desire to control other key regions of the world. The parameters of imperial politics are still in place and the driving orientation of an imperial mentality has not been superceded. The argument is organised around three intertwined themes. First, there is an identification and differentiation of the key concepts that are to be found in discussions of colonial and imperial rule. Second, two contrasting theoretical approaches to the analysis of the imperial are considered, and an attempt is made to suggest ways in which the cultural and the Marxist political economy perspectives could be linked, even if only tenuously. Third the article examines the main components of what is termed the “imperial mentality”, within which it is suggested that a multi-dimensional contextualization of imperial power might well provide us with a more creative analytical opening. The author hopes to make clear that the imperial present and the geopolitics of power is a thematic which requires much more examination in what are acutely volatile times., En este artículo se afirma que, al contrario de lo que se piensa habitualmente, no estamos viviendo en tiempos “postimperiales”; por el contrario se sugiere que habitamos un terreno re-imperializado, en el sentido de que se ha reafirmado la razón imperial, como queda patente, por ejemplo, en las invasiones de Irak y Afganistán —intervenciones que expresan el deseo occidental de controlar otras regiones clave del mundo—. Los parámetros de la política imperial están todavía vigentes y la orientación decisiva de una mentalidad imperial no ha sido desbancada. El argumento se organiza en torno a tres temas entremezclados. En primer lugar, se identifican y diferencian los conceptos clave que podemos encontrar en los debates sobre gobierno imperial y colonial. En segundo lugar, se consideran dos perspectivas teóricas contrapuestas, y se hace un intento de sugerir formas para unir, aunque sea tenuemente, la perspectiva cultural con la de la economía política marxista. Y en tercer lugar, el artículo examina los principales componentes de lo que se puede denominar la “mentalidad imperial”, a partir de la que se sugiere que se puede desarrollar una contextualización multidimensional del poder imperial, que bien podría proporcionarnos una apertura analítica más creativa. El autor espera dejar claro que el presente imperial y la geopolítica del poder son una temática que necesita un examen más profundo en estos tiempos tan volátiles., Neste artigo, afirma-se que, ao contrário do que se pensa habitualmente, não estamos vivendo em tempos “pós-imperiais”. Ao contrário, sugere-se que habitamos um terreno re-imperializado, no sentido de uma reafirmação da razão imperial, como fica claro, por exemplo, nas invasões do Iraque e do Afeganistão – intervenções que expressam o desejo ocidental de controlar outras regiões chave do mundo. Os parâmetros da política imperial ainda estão vigentes e a orientação decisiva de uma mentalidade imperial não foi desbancada. O argumento do texto divide-se em três temas inter-relacionados. Em primeiro lugar, identificam- se e diferenciam-se os conceitos principais que podemos encontrar nos debates sobre governo imperial e colonial. Em segundo lugar, consideram-se as perspectivas teóricas enfrentadas, e propõe-se uma tentativa de articulação, ainda que tênue, da corrente cultural com a economia política marxista. Finalmente, em terceiro lugar, o artigo examina os principais componentes do que pode ser denominado como “mentalidade imperial”, sugerindo que é possível desenvolver uma contextualização multidimensional do poder imperial, que poderia proporcionar uma abertura analítica mais criativa. O autor espera deixar claro que o presente imperial e a geopolítica do poder são uma temática que necessita uma análise mais profunda nestes tempos tão voláteis.

We investigate the impact of node capture attacks on the confidentiality and integrity of network traffic. We map the compromise of network traffic to the flow of current through an electric circuit and propose a metric for quantifying the vulnerability of the traffic using the circuit mapping. We compute the vulnerability metric as a function of the routing and the cryptographic protocols used to secure the network traffic. We formulate the minimum cost node capture attack problem as a nonlinear integer programming problem. Due to the NP-hardness of the minimization problem, we provide a greedy heuristic that approximates the minimum cost attack. We provide examples of node capture attacks using our vulnerability metric and show that the adversary can expend significantly less resources to compromise target traffic by exploiting information leakage from the routing and cryptographic protocols., Sponsored in part by Army Research Office Grants nos. W911NF-05-1-0491 and W911NF-07-1-0287 and Army Research Lab Grant no. DAAD19-01-2-0011. Prepared in collaboration with the Center for High Assurance Computer Systems, Naval Research Laboratory, Washington, DC. Presented at the IEEE Conference on Computer Communications (27th), INFORCOM'08, Phoenix, AZ, 15-17 April 2008. The original document contains color images.