1,720,975 research outputs found
Integrating CSI Sensing in Wireless Networks: Challenges to Privacy and Countermeasures
Full text linkThe path toward 6G is still long and blurred, but a few key points seem to be already decided: integration of many different access networks; adoption of massive MIMO technologies; use of frequencies above current radio spectrum up to THz and beyond; and inclusion of artificial intelligence and machine learning in standard management and operations. One additional point that is less discussed, but seems key for success, is the advanced use of channel state information (CSI) for both equalization and decoding purposes as well as for sensing ones. CSI-based sensing promises a plethora of new applications and a quantum leap in service personalization and customer-centric network management. At the same time, CSI analysis, being based on the physical characteristics of the propagated signal, poses novel threats to people's privacy and security: No software-based solution or cryptographic method above the physical layer can prevent the analysis of CSI. CSI analysis can reveal people's position or activity, allow tracking them, and discover details on the environment that today can be seen only with cameras or radars. In this article, we discuss the current status of CSI-based sensing and present some technologies that can protect people's privacy and at the same time allow legitimate use of the information carried by the CSI to offer better services
Wi-Fi Localization Obfuscation: An implementation in openwifi
Full text linkWi-Fi sensing as a side-effect of communications is opening new opportunities for smart services integrating communications with environmental properties, first and foremost the position of devices and people. At the same time, this technology represents an unprecedented threat to people's privacy, as personal information can be collected directly at the physical layer without any possibility to hide or protect it. Several works already discussed the possibility of safeguarding users’ privacy without hampering communication performance, using signal pre-processing at the transmitter side to introduce pseudo-random (artificial) patterns in the channel response estimated at the receiver, preventing the extraction of meaningful information from the channel state, a process called obfuscation. One step beyond the proof-of-concept for obfuscation feasibility, is its implementation in working systems. In this work, we present the implementation of a location obfuscation technique within the openwifi project that enables fine manipulation of the radio signal at transmitter side and yields acceptable, if not good, performance, the system has been implemented for both 802.11a/g/h and 802.11n systems, including MPDU aggregation, while implementation for 802.11ac or ax is still not feasible because openwifi does not support 40MHz channelization and beyond. This contribution discusses the implementation of the obfuscation subsystem, its performance, possible improvements, and further steps to allow authorized devices to “de-obfuscate” the signal and retrieve the sensed information
On the Progressive Introduction of Heterogeneous CACC Capabilities
Full text linkCan we introduce Cooperative Adaptive Cruise Control (CACC) technologies on the road without separated road infrastructures? This simple question is often latent in works dealing with cooperative driving, especially in feasibility analysis of cooperative driving. As of today, the question has indeed received no definitive answer in the literature because it is hard to model analytically heterogeneous systems or to experiment with them. This work helps understanding how vehicles interact among each others when they do not run a single, a-priory defined, CACC algorithm, but rather each vehicle adopt its own one. We introduce the concept of mixed platoon, i.e., a string of vehicles where more than one CACC algorithm is used, and we experiment with mixed platoons in silico to study how the mixture of CACC algorithms affects efficiency and safety. For instance we analyze scenarios where we progressively introduce homogeneous and mixed platoons among standard Adaptive Cruise Control (ACC) vehicles, quantifying the positive or negative effects on traffic efficiency and safety induced by the introduction of CACC technologies as a function of their penetration rate. The obtained results encourage additional research on the topic, starting from theoretical analysis of mixed platoons down to performance evaluations of actual implementations
On the Implementation of Location Obfuscation in openwifi and Its Performance
Full text linkWi-Fi sensing as a side-effect of communications is opening new opportunities for smart services integrating communications with environmental properties, first and foremost the position of devices and people. At the same time, this technology represents an unprecedented threat to people’s privacy, as personal information can be collected directly at the physical layer without any possibility to hide or protect it. Several works already discussed the possibility of safeguarding users’ privacy without hampering communication performance. Usually, some signal pre-processing at the transmitter side is needed to introduce pseudo-random (artificial) patterns in the channel response estimated at the receiver, preventing the extraction of meaningful information from the channel state. However, there is currently just one implementation of such techniques in a real system (openwifi), and it has never been tested for performance. In this work, we present the implementation of a location obfuscation technique within the openwifi project that enables fine manipulation of the radio signal at transmitter side and yields acceptable, if not good, performance. The paper discusses the implementation of the obfuscation subsystem, its performance, possible improvements, and further steps to allow authorized devices to “de-obfuscate” the signal and retrieve the sensed information
Exact Distributed Load Centrality Computation: Algorithms, Convergence, and Applications to Distance Vector Routing
Full text linkMany optimization techniques for networking protocols take advantage of topological information to improve performance. Often, the topological information at the core of these techniques is a centrality metric such as the Betweenness Centrality (BC) index. BC is, in fact, a centrality metric with many well-known successful applications documented in the literature, from resource allocation to routing. To compute BC, however, each node must run a centralized algorithm and needs to have the global topological knowledge; such requirements limit the feasibility of optimization procedures based on BC. To overcome restrictions of this kind, we present a novel distributed algorithm that requires only local information to compute an alternative similar metric, called Load Centrality (LC). We present the new algorithm together with a proof of its convergence and the analysis of its time complexity. The proposed algorithm is general enough to be integrated with any distance vector (DV) routing protocol. In support of this claim, we provide an implementation on top of Babel, a real-world DV protocol. We use this implementation in an emulation framework to show how LC can be exploited to reduce Babel's convergence time upon node failure, without increasing control overhead. As a key step towards the adoption of centrality-based optimization for routing, we study how the algorithm can be incrementally introduced in a network running a DV routing protocol. We show that even when only a small fraction of nodes participate in the protocol, the algorithm accurately ranks nodes according to their centrality
Increased exhaled 8-isoprostanes in childhood asthma
No full textSTUDY OBJECTIVE:
To quantify lung oxidative stress in asthmatic children by measuring concentrations of 8-isoprostane, a marker of oxidative stress, in exhaled breath condensate (EBC), which is a noninvasive method of sampling airway secretions. Secondary objectives were as follows: (1) to measure levels of exhaled prostaglandin (PG) E(2), since impaired PGE(2) production has been implicated in the pathogenesis of asthma in adults; and (2) to measure levels of fractional exhaled nitric oxide (FeNO), which is a marker of airway inflammation.
DESIGN:
Single-center, cross-sectional study.
PATIENTS:
Twelve healthy children, 12 steroid-naïve asthmatic children, and 30 children in stable condition with mild-to-moderate persistent asthma who were being treated with inhaled corticosteroids (ICSs) [average dose, 300 micro g per day] were studied.
INTERVENTIONS:
Subjects attended the outpatient clinic on one occasion for the collection of EBC and FeNO measurements. Measurements and results: 8-Isoprostane and PGE(2) concentrations in EBC were measured with specific radioimmunoassays. FeNO was measured online by a chemiluminescence analyzer. 8-Isoprostane was detectable in the EBC of healthy children (mean [+/- SEM], 34.2 +/- 4.5 pg/mL), and its concentrations were increased in both steroid-naïve asthmatic children (mean, 56.4 +/- 7.7 pg/mL; p < 0.01) and steroid-treated asthmatic children (mean, 47.2 +/- 2.3 pg/mL; p < 0.05). There was no difference in exhaled 8-isoprostane concentrations between the two groups of asthmatic children (p = 0.14). By contrast, exhaled PGE(2) concentrations were similar among the three study groups (p = 0.56). FeNO levels were higher in steroid-naïve children with asthma (49.2 +/- 9.6 parts per billion [ppb]; p < 0.05) and, to a lesser extent, in steroid-treated asthmatic children (37.8 +/- 6.6 ppb; p < 0.05) compared with healthy children (15.2 +/- 1.7 ppb).
CONCLUSIONS:
Lung oxidative stress is increased in children who are in stable condition with asthma, as reflected by increased exhaled 8-isoprostane concentrations. This increase seems to be relatively resistant to treatment with ICSs. Decreased PGE(2) lung production is unlikely to play a pathophysiologic role in childhood asthma
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