1,512 research outputs found
Characterization and application of objective pilling classification to patterned fabrics
Previously, the authors proposed a new, simple method of frequency domain analysis based on the two-dimensional discrete wavelet transform to objectively measure the pilling intensity in sample fabric images. The method was further characterized, and the results obtained indicate that standard deviation and variance are the most appropriate measures of the dispersion of wavelet details coefficients for analysis, that the relationship between wavelet analysis scale and fabric inter-yarn pitch was empirically confirmed, and, that fabrics with random patterns do not appear to impact on the effectiveness of the analysis method. <br /
KISS: Stochastic Packet Inspection Classifier for UDP Traffic
This paper proposes KISS, a novel Internet classifica- tion engine. Motivated by the expected raise of UDP traffic, which stems from the momentum of Peer-to-Peer (P2P) streaming appli- cations, we propose a novel classification framework that leverages on statistical characterization of payload. Statistical signatures are derived by the means of a Chi-Square-like test, which extracts the protocol "format," but ignores the protocol "semantic" and "synchronization" rules. The signatures feed a decision process based either on the geometric distance among samples, or on Sup- port Vector Machines. KISS is very accurate, and its signatures are intrinsically robust to packet sampling, reordering, and flow asym- metry, so that it can be used on almost any network. KISS is tested in different scenarios, considering traditional client-server proto- cols, VoIP, and both traditional and new P2P Internet applications. Results are astonishing. The average True Positive percentage is 99.6%, with the worst case equal to 98.1,% while results are al- most perfect when dealing with new P2P streaming applications
Conceptual modelling to assess how the interplay of hydrological connectivity, catchment storage and tracer dynamics controls nonstationary water age estimates
Acknowledgements We would like to gratefully acknowledge the data provided by SEPA, Iain Malcolm. Mark Speed, Susan Waldron and many MSS staff helped with sample collection and lab analysis. We thank the European Research Council (project GA 335910 VEWA) for funding and are grateful for the constructive comments provided by three anonymous reviewers.Peer reviewedPostprin
Spatial aggregation of time-variant stream water ages in urbanizing catchments
Date of Acceptance: 25/03/2015 Acknowledgements The help of Clara F. Soulsby with the sampling is gratefully acknowledged.Peer reviewedPostprin
On Modeling the Costs of Censorship
We argue that the evaluation of censorship evasion tools should depend upon
economic models of censorship. We illustrate our position with a simple model
of the costs of censorship. We show how this model makes suggestions for how to
evade censorship. In particular, from it, we develop evaluation criteria. We
examine how our criteria compare to the traditional methods of evaluation
employed in prior works
Novel geometric features for off-line writer identification
Writer identification is an important field in forensic document examination. Typically, a writer identification system consists of two main steps: feature extraction and matching and the performance depends significantly on the feature extraction step. In this paper, we propose a set of novel geometrical features that are able to characterize different writers. These features include direction, curvature, and tortuosity. We also propose an improvement of the edge-based directional and chain code-based features. The proposed methods are applicable to Arabic and English handwriting. We have also studied several methods for computing the distance between feature vectors when comparing two writers. Evaluation of the methods is performed using both the IAM handwriting database and the QUWI database for each individual feature reaching Top1 identification rates of 82 and 87 % in those two datasets, respectively. The accuracies achieved by Kernel Discriminant Analysis (KDA) are significantly higher than those observed before feature-level writer identification was implemented. The results demonstrate the effectiveness of the improved versions of both chain-code features and edge-based directional features
Reviewing Traffic ClassificationData Traffic Monitoring and Analysis
Traffic classification has received increasing attention in the last years. It aims at offering the ability to automatically recognize the application that has generated a given stream of packets from the direct and passive observation of the individual packets, or stream of packets, flowing in the network. This ability is instrumental to a number of activities that are of extreme interest to carriers, Internet service providers and network administrators in general. Indeed, traffic classification is the basic block that is required to enable any traffic management operations, from differentiating traffic pricing and treatment (e.g., policing, shaping, etc.), to security operations (e.g., firewalling, filtering, anomaly detection, etc.). Up to few years ago, almost any Internet application was using well-known transport layer protocol ports that easily allowed its identification. More recently, the number of applications using random or non-standard ports has dramatically increased (e.g. Skype, BitTorrent, VPNs, etc.). Moreover, often network applications are configured to use well-known protocol ports assigned to other applications (e.g. TCP port 80 originally reserved for Web traffic) attempting to disguise their presence. For these reasons, and for the importance of correctly classifying traffic flows, novel approaches based respectively on packet inspection, statistical and machine learning techniques, and behavioral methods have been investigated and are becoming standard practice. In this chapter, we discuss the main trend in the field of traffic classification and we describe some of the main proposals of the research community. We complete this chapter by developing two examples of behavioral classifiers: both use supervised machine learning algorithms for classifications, but each is based on different features to describe the traffic. After presenting them, we compare their performance using a large dataset, showing the benefits and drawback of each approac
Eigen-spectrograms: an interpretable feature space for bearing fault diagnosis based on artificial intelligence and image processing
The Intelligent Fault Diagnosis of rotating machinery proposes some
captivating challenges in light of the imminent big data era. Although results
achieved by artificial intelligence and deep learning constantly improve, this
field is characterized by several open issues. Models' interpretation is still
buried under the foundations of data driven science, thus requiring attention
to the development of new opportunities also for machine learning theories.
This study proposes a machine learning diagnosis model, based on intelligent
spectrogram recognition, via image processing. The approach is characterized by
the introduction of the eigen-spectrograms and randomized linear algebra in
fault diagnosis. The eigen-spectrograms hierarchically display inherent
structures underlying spectrogram images. Also, different combinations of
eigen-spectrograms are expected to describe multiple machine health states.
Randomized algebra and eigen-spectrograms enable the construction of a
significant feature space, which nonetheless emerges as a viable device to
explore models' interpretations. The computational efficiency of randomized
approaches further collocates this methodology in the big data perspective and
provides new reading keys of well-established statistical learning theories,
such as the Support Vector Machine (SVM). The conjunction of randomized algebra
and Support Vector Machine for spectrogram recognition shows to be extremely
accurate and efficient as compared to state of the art results.Comment: 14 pages, 13 figure
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