3,891 research outputs found
Anonymous reputation based reservations in e-commerce (AMNESIC)
Online reservation systems have grown over the last recent
years to facilitate the purchase of goods and services. Generally,
reservation systems require that customers provide
some personal data to make a reservation effective. With
this data, service providers can check the consumer history
and decide if the user is trustable enough to get the reserve.
Although the reputation of a user is a good metric to implement
the access control of the system, providing personal
and sensitive data to the system presents high privacy risks,
since the interests of a user are totally known and tracked
by an external entity. In this paper we design an anonymous
reservation protocol that uses reputations to profile
the users and control their access to the offered services, but
at the same time it preserves their privacy not only from the
seller but the service provider
Experimental investigation of the mooring system of a wave energy converter in operating and extreme wave conditions
A proper design of the mooring systems for Wave Energy Converters (WECs) requires an accurate investigation of both operating and extreme wave conditions. A careful analysis of these systems is required to design a mooring configuration that ensures station keeping, reliability, maintainability, and low costs, without affecting the WEC dynamics. In this context, an experimental campaign on a 1:20 scaled prototype of the ISWEC (Inertial Sea Wave Energy Converter), focusing on the influence of the mooring layout on loads in extreme wave conditions, is presented and discussed. Two mooring configurations composed of multiple slack catenaries with sub-surface buoys, with or without clump-weights, have been designed and investigated experimentally. Tests in regular, irregular, and extreme waves for a moored model of the ISWEC device have been performed at the University of Naples Federico II. The aim is to identify a mooring solution that could guarantee both correct operation of the device and load carrying in extreme sea conditions. Pitch motion and loads in the rotational joint have been considered as indicators of the device hydrodynamic behavior and mooring configuration impact on the WEC
INITIAL DESIGN, MANUFACTURE, AND TESTING OF A CUBELAB MODULE FRAME FOR BIOLOGICAL PAYLOADS ABOARD THE INTERNATIONAL SPACE STATION
This thesis investigates the design of a CubeLab Module frame to facilitate biological research aboard the International Space Station (ISS). With the National Laboratory designation of the ISS by the United States Congress the barriers for use of the facility have been lowered for commercial and academic entities, allowing greater volume and diversity in the research that can be done. Researchers in biology and other areas could benefit from development and adoption of a plug-and-play payload containment system for use in the microgravity/space environment of the ISS. This research includes design and analysis of such a system. It also includes production and testing of a prototype. The relevant NASA requirements are documented, and they were considered during the design phase. Results from finite element analyses to predict performance of a proposed design under expected service conditions are reported. Results from functional testing of the prototype are also provided. A discussion of future work needed before the structure outlined in this thesis can become commercially viable is also presented
Hardware/software 2D-3D backprojection on a SoPC platform
International audienceThe reduction of image reconstruction time is needed to spread the use of PET for research and routine clinical practice. In this purpose, this article presents a hardware/software architecture for the acceleration of 3D backprojection based upon an efficient 2D backprojection. This architecture has been designed in order to provide a high level of parallelism thanks to an efficient management of the memory accesses which would have been otherwise strongly slowed by the external memory. The reconstruction system is embedded in a SoPC platform (System on Programmable Chip), the new generation of reconfigurable circuit. The originality of this architecture comes from the design of a 2D Adaptative and Predictive Cache (2D-AP Cache) which has proved to be an efficient way to overcome the memory access bottleneck. Thanks to a hierarchical use of this cache, several backprojection operators can run in parallel, accelerating in this manner noteworthy the reconstruction process. This 2D reconstruction system will next be used to speed up 3D image reconstruction
Upgrade of the NA61/SHINE facility beyond 2020 for an expanded physics programme
The NA61/SHINE experiment studies hadron production in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions. The physics programme includes the study of the onset of deconfinement and search for the critical point as well as reference measurements for neutrino and cosmic ray experiments. For strong interactions, future plans are to extend the programme of study of the onset of deconfinement by measurements of open-charm and possibly other short-lived, exotic particle production in nucleus-nucleus collisions. This new programme is planned to start after 2020 and requires upgrades to the present NA61/SHINE detector setup. Besides the construction of a large acceptance silicon detector, a 10-fold increase of the event recording rate is foreseen, which will necessitate a general upgrade of most detectors
CyberSpec: Intelligent Behavioral Fingerprinting to Detect Attacks on Crowdsensing Spectrum Sensors
Integrated sensing and communication (ISAC) is a novel paradigm using
crowdsensing spectrum sensors to help with the management of spectrum scarcity.
However, well-known vulnerabilities of resource-constrained spectrum sensors
and the possibility of being manipulated by users with physical access
complicate their protection against spectrum sensing data falsification (SSDF)
attacks. Most recent literature suggests using behavioral fingerprinting and
Machine/Deep Learning (ML/DL) for improving similar cybersecurity issues.
Nevertheless, the applicability of these techniques in resource-constrained
devices, the impact of attacks affecting spectrum data integrity, and the
performance and scalability of models suitable for heterogeneous sensors types
are still open challenges. To improve limitations, this work presents seven
SSDF attacks affecting spectrum sensors and introduces CyberSpec, an
ML/DL-oriented framework using device behavioral fingerprinting to detect
anomalies produced by SSDF attacks affecting resource-constrained spectrum
sensors. CyberSpec has been implemented and validated in ElectroSense, a real
crowdsensing RF monitoring platform where several configurations of the
proposed SSDF attacks have been executed in different sensors. A pool of
experiments with different unsupervised ML/DL-based models has demonstrated the
suitability of CyberSpec detecting the previous attacks within an acceptable
timeframe
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