Non-Cooperative Location Privacy Freudiger, J.; Manshaei, M. H.; Hubaux, Jean-Pierre ...
IEEE Transactions on Dependable and Secure Computing/IEEE transactions on dependable and secure computing,
03/2013, Letnik:
10, Številka:
2
Journal Article
Odprti dostop
In mobile networks, authentication is a required primitive for most security protocols. Unfortunately, an adversary can monitor pseudonyms used for authentication to track the location of mobile ...nodes. A frequently proposed solution to protect location privacy suggests that mobile nodes collectively change their pseudonyms in regions called mix zones. This approach is costly. Self-interested mobile nodes might, thus, decide not to cooperate and jeopardize the achievable location privacy. In this paper, we analyze non-cooperative behavior of mobile nodes by using a game-theoretic model, where each player aims at maximizing its location privacy at a minimum cost. We obtain Nash equilibria in static n-player complete information games. As in practice mobile nodes do not know their opponents' payoffs, we then consider static incomplete information games. We establish that symmetric Bayesian-Nash equilibria exist with simple threshold strategies. By means of numerical results, we predict behavior of selfish mobile nodes. We then investigate dynamic games where players decide to change their pseudonym one after the other and show how this affects strategies at equilibrium. Finally, we design protocols-PseudoGame protocols-based on the results of our analysis and simulate their performance in vehicular network scenarios.
Machines powered by artificial intelligence increasingly mediate our social, cultural, economic and political interactions. Understanding the behaviour of artificial intelligence systems is essential ...to our ability to control their actions, reap their benefits and minimize their harms. Here we argue that this necessitates a broad scientific research agenda to study machine behaviour that incorporates and expands upon the discipline of computer science and includes insights from across the sciences. We first outline a set of questions that are fundamental to this emerging field and then explore the technical, legal and institutional constraints on the study of machine behaviour.
Summary The proportion and severity of Clostridium difficile -associated diarrhoea (CDAD) is increasing in health-care settings. Antibiotics remain the most important risk factor for CDAD, due to ...their limiting the ability of the gastrointestinal flora to inhibit C difficile colonisation. Probiotics have therefore been investigated for primary and secondary prophylaxis against CDAD, with varying success. This Review looks at the current literature for in-vitro and clinical evidence for probiotic use in the prevention of CDAD. Its aim is to examine the mechanisms through which probiotics interact with C difficile and its toxin, and the association of these mechanisms with the clinical evidence for probiotics in the prevention of this disease. The Review briefly describes the recent epidemiological changes in C difficile disease, and our current understanding of its pathophysiology. It looks at the safety profile of probiotics, highlighting patients groups in which their use is inappropriate, and attempts to synthesise guidance for clinicians interested in using probiotics to prevent CDAD within health-care institutions.
Computational-mechanism design has an important role to play in developing complex distributed systems comprising multiple interacting agents. Game theory has developed powerful tools for analyzing, ...predicting, and controlling the behavior of self-interested agents and decision making in systems with multiple autonomous actors. These tools, when tailored to computational settings, provide a foundation for building multiagent software systems. This tailoring gives rise to the field of computational-mechanism design, which applies economic principles to computer systems design.
PurposeTo report near-infrared reflectance (NIR-R), near-infrared autofluorescence (NIR-AF) and blue wave autofluorescence (BW-AF) appearance of choroidal nevi using a confocal scanning laser ...ophthalmoscope (cSLO).Patients and methodsNIR-R, NIR-AF and BW-AF images of choroidal nevi were compared with color fundus photos (CF). Images were graded as hyperreflective if reflectance was much greater than background, hyporeflective if less than background, and isoreflective if the same as the background.ResultsForty-two nevi of 39 patients were imaged. When compared with CF, nevi could be identified on 95% (40/42) NIR-R images (95% CI: 83.5-99.3). On NIR-R 71% (30/42) demonstrated hyperreflectance and 24% (10/42) were hyporeflective. Hyperreflectivity was demonstrated in 96% (23/24) of NIR-AF images (95% CI: 79.1-99.9) and 34% (14/41) of BW-AF images (95% CI: 20.0-50.5). On NIR-R, 29/40 (73%) were apparently smaller in comparison with CF and 11/40 (28%) had the same area. A correlation was found between NIR-R and NIR-AF (P=0.02) but not with BW-AF (P=0.15).ConclusionsNevi can be visualized well using NIR-R and NIR-AF imaging modalities, but are less frequently visible using BW-AF. These changes may be related to melanin within the choroid or chronic changes of the overlying retinal pigment epithelium.
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