31,422 research outputs found
Detection of Cyber-Physical Faults and Intrusions from Physical Correlations
Cyber-physical systems are critical infrastructures that are crucial both to
the reliable delivery of resources such as energy, and to the stable
functioning of automatic and control architectures. These systems are composed
of interdependent physical, control and communications networks described by
disparate mathematical models creating scientific challenges that go well
beyond the modeling and analysis of the individual networks. A key challenge in
cyber-physical defense is a fast online detection and localization of faults
and intrusions without prior knowledge of the failure type. We describe a set
of techniques for the efficient identification of faults from correlations in
physical signals, assuming only a minimal amount of available system
information. The performance of our detection method is illustrated on data
collected from a large building automation system.Comment: 10 pages, 9 figure
Optimisation of Mobile Communication Networks - OMCO NET
The mini conference “Optimisation of Mobile Communication Networks” focuses on advanced methods for search and optimisation applied to wireless communication networks. It is sponsored by Research & Enterprise Fund Southampton Solent University.
The conference strives to widen knowledge on advanced search methods capable of optimisation of wireless communications networks. The aim is to provide a forum for exchange of recent knowledge, new ideas and trends in this progressive and challenging area. The conference will popularise new successful approaches on resolving hard tasks such as minimisation of transmit power, cooperative and optimal routing
Anomaly Detection: Review and preliminary Entropy method tests
Anomalies are strange data points; they usually represent an unusual
occurrence. Anomaly detection is presented from the perspective of Wireless
sensor networks. Different approaches have been taken in the past, as we will
see, not only to identify outliers, but also to establish the statistical
properties of the different methods. The usual goal is to show that the
approach is asymptotically efficient and that the metric used is unbiased or
maybe biased.
This project is based on a work done by [1]. The approach is based on the
principle that the entropy of the data is increased when an anomalous data
point is measured. The entropy of the data set is thus to be estimated. In this
report however, preliminary efforts at confirming the results of [1] is
presented. To estimate the entropy of the dataset, since no parametric form is
assumed, the probability density function of the data set is first estimated
using data split method. This estimated pdf value is then plugged-in to the
entropy estimation formula to estimate the entropy of the dataset. The data
(test signal) used in this report is Gaussian distributed with zero mean and
variance 4. Results of pdf estimation using the k-nearest neighbour method
using the entire dataset, and a data-split method are presented and compared
based on how well they approximate the probability density function of a
Gaussian with similar mean and variance. The number of nearest neighbours
chosen for the purpose of this report is 8. This is arbitrary, but is
reasonable since the number of anomalies introduced is expected to be less than
this upon data-split. The data-split method is preferred and rightly so
Effective Connectivity-Based Neural Decoding: A Causal Interaction-Driven Approach
We propose a geometric model-free causality measurebased on multivariate
delay embedding that can efficiently detect linear and nonlinear causal
interactions between time series with no prior information. We then exploit the
proposed causal interaction measure in real MEG data analysis. The results are
used to construct effective connectivity maps of brain activity to decode
different categories of visual stimuli. Moreover, we discovered that the
MEG-based effective connectivity maps as a response to structured images
exhibit more geometric patterns, as disclosed by analyzing the evolution of
toplogical structures of the underlying networks using persistent homology.
Extensive simulation and experimental result have been carried out to
substantiate the capabilities of the proposed approach.Comment: 16 pages, 13 figures, 2 table
Application of Compressive Sensing Techniques in Distributed Sensor Networks: A Survey
In this survey paper, our goal is to discuss recent advances of compressive
sensing (CS) based solutions in wireless sensor networks (WSNs) including the
main ongoing/recent research efforts, challenges and research trends in this
area. In WSNs, CS based techniques are well motivated by not only the sparsity
prior observed in different forms but also by the requirement of efficient
in-network processing in terms of transmit power and communication bandwidth
even with nonsparse signals. In order to apply CS in a variety of WSN
applications efficiently, there are several factors to be considered beyond the
standard CS framework. We start the discussion with a brief introduction to the
theory of CS and then describe the motivational factors behind the potential
use of CS in WSN applications. Then, we identify three main areas along which
the standard CS framework is extended so that CS can be efficiently applied to
solve a variety of problems specific to WSNs. In particular, we emphasize on
the significance of extending the CS framework to (i). take communication
constraints into account while designing projection matrices and reconstruction
algorithms for signal reconstruction in centralized as well in decentralized
settings, (ii) solve a variety of inference problems such as detection,
classification and parameter estimation, with compressed data without signal
reconstruction and (iii) take practical communication aspects such as
measurement quantization, physical layer secrecy constraints, and imperfect
channel conditions into account. Finally, open research issues and challenges
are discussed in order to provide perspectives for future research directions
Life detection strategy based on infrared vision and ultra-wideband radar data fusion
The life detection method based on a single type of information source cannot
meet the requirement of post-earthquake rescue due to its limitations in
different scenes and bad robustness in life detection. This paper proposes a
method based on deep neural network for multi-sensor decision-level fusion
which concludes Convolutional Neural Network and Long Short Term Memory neural
network (CNN+LSTM). Firstly, we calculate the value of the life detection
probability of each sensor with various methods in the same scene
simultaneously, which will be gathered to make samples for inputs of the deep
neural network. Then we use Convolutional Neural Network (CNN) to extract the
distribution characteristics of the spatial domain from inputs which is the
two-channel combination of the probability values and the smoothing probability
values of each life detection sensor respectively. Furthermore, the sequence
time relationship of the outputs from the last layers will be analyzed with
Long Short Term Memory (LSTM) layers, then we concatenate the results from
three branches of LSTM layers. Finally, two sets of LSTM neural networks that
is different from the previous layers are used to integrate the three branches
of the features, and the results of the two classifications are output using
the fully connected network with Binary Cross Entropy (BEC) loss function.
Therefore, the classification results of the life detection can be concluded
accurately with the proposed algorithm.Comment: 6 pages, 7 figures, conferenc
Sensor Configuration and Activation for Field Detection in Large Sensor Arrays
The problems of sensor configuration and activation for the detection of
correlated random fields using large sensor arrays are considered. Using
results that characterize the large-array performance of sensor networks in
this application, the detection capabilities of different sensor configurations
are analyzed and compared. The dependence of the optimal choice of
configuration on parameters such as sensor signal-to-noise ratio (SNR), field
correlation, etc., is examined, yielding insights into the most effective
choices for sensor selection and activation in various operating regimes.Comment: 7 pages with 11 figures; also to appear in the Fourth International
Conference on Information Processing in Sensor Network
A Journey from Improper Gaussian Signaling to Asymmetric Signaling
The deviation of continuous and discrete complex random variables from the
traditional proper and symmetric assumption to a generalized improper and
asymmetric characterization (accounting correlation between a random entity and
its complex conjugate), respectively, introduces new design freedom and various
potential merits. As such, the theory of impropriety has vast applications in
medicine, geology, acoustics, optics, image and pattern recognition, computer
vision, and other numerous research fields with our main focus on the
communication systems. The journey begins from the design of improper Gaussian
signaling in the interference-limited communications and leads to a more
elaborate and practically feasible asymmetric discrete modulation design. Such
asymmetric shaping bridges the gap between theoretically and practically
achievable limits with sophisticated transceiver and detection schemes in both
coded/uncoded wireless/optical communication systems. Interestingly,
introducing asymmetry and adjusting the transmission parameters according to
some design criterion render optimal performance without affecting the
bandwidth or power requirements of the systems. This dual-flavored article
initially presents the tutorial base content covering the interplay of
reality/complexity, propriety/impropriety and circularity/noncircularity and
then surveys majority of the contributions in this enormous journey.Comment: IEEE COMST (Early Access
Online Multivariate Anomaly Detection and Localization for High-dimensional Settings
This paper considers the real-time detection of anomalies in high-dimensional
systems. The goal is to detect anomalies quickly and accurately so that the
appropriate countermeasures could be taken in time, before the system possibly
gets harmed. We propose a sequential and multivariate anomaly detection method
that scales well to high-dimensional datasets. The proposed method follows a
nonparametric, i.e., data-driven, and semi-supervised approach, i.e., trains
only on nominal data. Thus, it is applicable to a wide range of applications
and data types. Thanks to its multivariate nature, it can quickly and
accurately detect challenging anomalies, such as changes in the correlation
structure and stealth low-rate cyberattacks. Its asymptotic optimality and
computational complexity are comprehensively analyzed. In conjunction with the
detection method, an effective technique for localizing the anomalous data
dimensions is also proposed. We further extend the proposed detection and
localization methods to a supervised setup where an additional anomaly dataset
is available, and combine the proposed semi-supervised and supervised
algorithms to obtain an online learning algorithm under the semi-supervised
framework. The practical use of proposed algorithms are demonstrated in DDoS
attack mitigation, and their performances are evaluated using a real IoT-botnet
dataset and simulations.Comment: 16 pages, LaTeX; references adde
POP-CNN: Predicting Odor's Pleasantness with Convolutional Neural Network
Predicting odor's pleasantness simplifies the evaluation of odors and has the
potential to be applied in perfumes and environmental monitoring industry.
Classical algorithms for predicting odor's pleasantness generally use a manual
feature extractor and an independent classifier. Manual designing a good
feature extractor depend on expert knowledge and experience is the key to the
accuracy of the algorithms. In order to circumvent this difficulty, we proposed
a model for predicting odor's pleasantness by using convolutional neural
network. In our model, the convolutional neural layers replace manual feature
extractor and show better performance. The experiments show that the
correlation between our model and human is over 90% on pleasantness rating. And
our model has 99.9% accuracy in distinguishing between absolutely pleasant or
unpleasant odors
- …