12,987 research outputs found
Hybrid Fusion for Biometrics: Combining Score-level and Decision-level Fusion
A general framework of fusion at decision level, which works on ROCs instead of matching scores, is investigated. Under this framework, we further propose a hybrid fusion method, which combines the score-level and decision-level fusions, taking advantage of both fusion modes. The hybrid fusion adaptively tunes itself between the two levels of fusion, and improves the final performance over the original two levels. The proposed hybrid fusion is simple and effective for combining different biometrics
How Unique is Your .onion? An Analysis of the Fingerprintability of Tor Onion Services
Recent studies have shown that Tor onion (hidden) service websites are
particularly vulnerable to website fingerprinting attacks due to their limited
number and sensitive nature. In this work we present a multi-level feature
analysis of onion site fingerprintability, considering three state-of-the-art
website fingerprinting methods and 482 Tor onion services, making this the
largest analysis of this kind completed on onion services to date.
Prior studies typically report average performance results for a given
website fingerprinting method or countermeasure. We investigate which sites are
more or less vulnerable to fingerprinting and which features make them so. We
find that there is a high variability in the rate at which sites are classified
(and misclassified) by these attacks, implying that average performance figures
may not be informative of the risks that website fingerprinting attacks pose to
particular sites.
We analyze the features exploited by the different website fingerprinting
methods and discuss what makes onion service sites more or less easily
identifiable, both in terms of their traffic traces as well as their webpage
design. We study misclassifications to understand how onion service sites can
be redesigned to be less vulnerable to website fingerprinting attacks. Our
results also inform the design of website fingerprinting countermeasures and
their evaluation considering disparate impact across sites.Comment: Accepted by ACM CCS 201
Predictive protocol of flocks with small-world connection pattern
By introducing a predictive mechanism with small-world connections, we
propose a new motion protocol for self-driven flocks. The small-world
connections are implemented by randomly adding long-range interactions from the
leader to a few distant agents, namely pseudo-leaders. The leader can directly
affect the pseudo-leaders, thereby influencing all the other agents through
them efficiently. Moreover, these pseudo-leaders are able to predict the
leader's motion several steps ahead and use this information in decision making
towards coherent flocking with more stable formation. It is shown that drastic
improvement can be achieved in terms of both the consensus performance and the
communication cost. From the industrial engineering point of view, the current
protocol allows for a significant improvement in the cohesion and rigidity of
the formation at a fairly low cost of adding a few long-range links embedded
with predictive capabilities. Significantly, this work uncovers an important
feature of flocks that predictive capability and long-range links can
compensate for the insufficiency of each other. These conclusions are valid for
both the attractive/repulsive swarm model and the Vicsek model.Comment: 10 pages, 12 figure
The low-noise optimisation method for gearbox in consideration of operating conditions
This paper presents a comprehensive procedure to calculate the steady dynamic response and the noise radiation generated from a stepping-down gearbox. In this process, the dynamic model of the cylindrical gear transmission system is built with the consideration of the time-varying mesh stiffness, gear errors and bearing supporting, while the data of dynamic bearing force is obtained through solving the model. Furthermore, taking the data of bearing force as the excitation, the gearbox vibrations and noise radiation are calculated by numerical simulation, and then the time history of node dynamic response, noise spectrum and resonance frequency range of the gearbox are obtained. Finally, the gearbox panel acoustic contribution at the resonance frequency range is calculated. Based on the conclusions from the gearbox panel acoustic contribution analyses and the mode shapes, two gearbox stiffness improving plans have been studied. By contrastive analysis of gearbox noise radiation, the effectiveness of the improving plans is confirmed. This study has provided useful theoretical guideline to the gearbox design
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