Performance Analysis
Real-time Out-of-distribution Detection in Learning-Enabled Cyber-Physical Systems
Cai, Feiyang, Koutsoukos, Xenofon
Xenofon Koutsoukos V anderbilt University Nashville, TN xenofon.koutsoukos@vanderbilt.edu Abstract --Cyber-physical systems (CPS) greatly benefit by using machine learning components that can handle the uncertainty and variability of the real-world. Typical components such as deep neural networks, however, introduce new types of hazards that may impact system safety. The system behavior depends on data that are available only during runtime and may be different than the data used for training. Out-of-distribution data may lead to a large error and compromise safety. The paper considers the problem of efficiently detecting out-of-distribution data in CPS control systems. Detection must be robust and limit the number of false alarms while being computational efficient for real-time monitoring. The proposed approach leverages inductive confor-mal prediction and anomaly detection for developing a method that has a well-calibrated false alarm rate. We use variational autoencoders and deep support vector data description to learn models that can be used efficiently compute the nonconformity of new inputs relative to the training set and enable real-time detection of out-of-distribution high-dimensional inputs. We demonstrate the method using an advanced emergency braking system and a self-driving end-to-end controller implemented in an open source simulator for self-driving cars. The simulation results show very small number of false positives and detection delay while the execution time is comparable to the execution time of the original machine learning components. I NTRODUCTION Learning-enabled components (LECs) such as neural networks are used in many classes of cyber-physical systems (CPS). Semi-autonomous and autonomous vehicles, in particular, are CPS examples where LECs can play a significant role for perception, planning, and control if they are complemented with methods for analyzing and ensuring safety [1], [2]. However, there are several characteristics of LECs that can complicate safety analysis. LECs encode knowledge in a form that is not transparent.
Survey of Network Intrusion Detection Methods from the Perspective of the Knowledge Discovery in Databases Process
Molina-Coronado, Borja, Mori, Usue, Mendiburu, Alexander, Miguel-Alonso, José
The identification of cyberattacks which target information and communication systems has been a focus of the research community for years. Network intrusion detection is a complex problem which presents a diverse number of challenges. Many attacks currently remain undetected, while newer ones emerge due to the proliferation of connected devices and the evolution of communication technology. In this survey, we review the methods that have been applied to network data with the purpose of developing an intrusion detector, but contrary to previous reviews in the area, we analyze them from the perspective of the Knowledge Discovery in Databases (KDD) process. As such, we discuss the techniques used for the capture, preparation and transformation of the data, as well as, the data mining and evaluation methods. In addition, we also present the characteristics and motivations behind the use of each of these techniques and propose more adequate and up-to-date taxonomies and definitions for intrusion detectors based on the terminology used in the area of data mining and KDD. Special importance is given to the evaluation procedures followed to assess the different detectors, discussing their applicability in current real networks. Finally, as a result of this literature review, we investigate some open issues which will need to be considered for further research in the area of network security.
Interpreting Machine Learning Malware Detectors Which Leverage N-gram Analysis
Briguglio, William, Saad, Sherif
In cyberattack detection and prevention systems, cybersecurity analysts always prefer solutions that are as interpretable and understandable as rule-based or signature-based detection. This is because of the need to tune and optimize these solutions to mitigate and control the effect of false positives and false negatives. Interpreting machine learning models is a new and open challenge. However, it is expected that an interpretable machine learning solution will be domain-specific. For instance, interpretable solutions for machine learning models in healthcare are different than solutions in malware detection. This is because the models are complex, and most of them work as a black-box. Recently, the increased ability for malware authors to bypass antimalware systems has forced security specialists to look to machine learning for creating robust detection systems. If these systems are to be relied on in the industry, then, among other challenges, they must also explain their predictions. The objective of this paper is to evaluate the current state-of-the-art ML models interpretability techniques when applied to ML-based malware detectors. We demonstrate interpretability techniques in practice and evaluate the effectiveness of existing interpretability techniques in the malware analysis domain.
How do We Quantify the Quality of Our Predictions? Part I
We have all worked on different kinds of Machine learning models, and each model needs to be evaluated in different ways. From the initial data that is provided to the outcome and the way, we as the users want to use it. A classification model would require a different metric for model evaluation as compared to a regression model or a Neural Net, and it's important to know and understand which metric to use and when. Here in this series, we go through some of these metrics, starting from the basic and the most commonly used ones to the application-specific and complex metrics that we can use. We will be starting with the basic metrics from sklearn and progress towards the more complicated metrics after that. Accuracy Score: In classification, the number of labels predicted for a sample versus the corresponding set of labels in y_true can be coined as accuracy.
Building a Lie Detector for Images
The Internet is full of fun fake images -- from flying sharks and cows on cars to a dizzying variety of celebrity mashups. Hyperrealistic image and video fakes generated by convolutional neural networks (CNNs) however are no laughing matter -- in fact they can be downright dangerous. Deepfake porn reared its ugly head in 2018, fake political speeches by world leaders have cast doubt on news sources, and during the recent Australian bushfires manipulated images mislead people regarding the location and size of fires. Fake images and videos are giving AI a black eye -- but how can the machine learning community fight back? A new paper from UC Berkeley and Adobe researchers declares war on fake images.
London Police to Deploy Facial Recognition Cameras Despite Privacy Concerns and Evidence of High Failure Rate
Police in London are moving ahead with a deploying a facial recognition camera system despite privacy concerns and evidence that the technology is riddled with false positives. The Metropolitan Police, the U.K.'s biggest police department with jurisdiction over most of London, announced Friday it would begin rolling out new "live facial recognition" cameras in London, making the capital one of the largest cities in the West to adopt the controversial technology. The "Met," as the police department is known in London, said in a statement the facial recognition technology, which is meant to identify people on a watch list and alert police to their real-time location, would be "intelligence-led" and deployed to only specific locations. It's expected to be rolled out as soon as next month. However, privacy activists immediately raised concerns, noting that independent reviews of trials of the technology showed a failure rate of 81%.
High noon for surveillance: resolving tension between the costs of false positives, challenges of calibration, and compliance – A Team
When it comes to trade surveillance, regulators want firms to do their own alert calibration, examine all alerts, and keep auditable records. Firms need to balance the real cost of false positives with the technical challenge and risk of self-calibrating and auto-calibrating, while compliance, IT and vendors have to grapple with the need for defensible and transparent audit, which challenges dynamic parameters. The webinar will review recent regulatory statements noting concerns about how trading organisations are setting parameters and managing surveillance. Moving on, it will discuss approaches and technologies that can mitigate these concerns, and question whether advanced approaches such as machine learning are a help or hindrance. Finally, it will set out practical plans for achieving successful surveillance for Market Abuse Regulation (MAR).
Lattice-based Improvements for Voice Triggering Using Graph Neural Networks
Dighe, Pranay, Adya, Saurabh, Li, Nuoyu, Vishnubhotla, Srikanth, Naik, Devang, Sagar, Adithya, Ma, Ying, Pulman, Stephen, Williams, Jason
Voice-triggered smart assistants often rely on detection of a trigger-phrase before they start listening for the user request. Mitigation of false triggers is an important aspect of building a privacy-centric non-intrusive smart assistant. In this paper, we address the task of false trigger mitigation (FTM) using a novel approach based on analyzing automatic speech recognition (ASR) lattices using graph neural networks (GNN). The proposed approach uses the fact that decoding lattice of a falsely triggered audio exhibits uncertainties in terms of many alternative paths and unexpected words on the lattice arcs as compared to the lattice of a correctly triggered audio. A pure trigger-phrase detector model doesn't fully utilize the intent of the user speech whereas by using the complete decoding lattice of user audio, we can effectively mitigate speech not intended for the smart assistant. We deploy two variants of GNNs in this paper based on 1) graph convolution layers and 2) self-attention mechanism respectively. Our experiments demonstrate that GNNs are highly accurate in FTM task by mitigating ~87% of false triggers at 99% true positive rate (TPR). Furthermore, the proposed models are fast to train and efficient in parameter requirements.
Detection of Thin Boundaries between Different Types of Anomalies in Outlier Detection using Enhanced Neural Networks
Kiani, Rasoul, Keshavarzi, Amin, Bohlouli, Mahdi
Outlier detection has received special attention in various fields, mainly for those dealing with machine learning and artificial intelligence. As strong outliers, anomalies are divided into the point, contextual and collective outliers. The most important challenges in outlier detection include the thin boundary between the remote points and natural area, the tendency of new data and noise to mimic the real data, unlabelled datasets and different definitions for outliers in different applications. Considering the stated challenges, we defined new types of anomalies called Collective Normal Anomaly and Collective Point Anomaly in order to improve a much better detection of the thin boundary between different types of anomalies. Basic domain-independent methods are introduced to detect these defined anomalies in both unsupervised and supervised datasets. The Multi-Layer Perceptron Neural Network is enhanced using the Genetic Algorithm to detect newly defined anomalies with higher precision so as to ensure a test error less than that calculated for the conventional Multi-Layer Perceptron Neural Network. Experimental results on benchmark datasets indicated reduced error of anomaly detection process in comparison to baselines.
Reasoning About Generalization via Conditional Mutual Information
Steinke, Thomas, Zakynthinou, Lydia
How can we ensure that a machine learning system produces an o utput that generalizes to the underlying distribution, rather than overfitting its train ing data? That is, how can we ensure that the hypotheses or models that are produced are reflective of t he underlying population the training data was drawn from, rather than patterns that occur only by c hance in the training data? This is perhaps the fundamental question for the science of statist ical machine learning. A vast array of methods have been proposed to answer this ques tion. Most notably, the theory of uniform convergence shows that, if the output is sufficiently "simple," then it cannot overfit too much. A more recent line of work has used distributional stability (in the form of differential privacy) to provide generalization guarantees that compose adaptivel y - that is, statistical validity is preserved even when a dataset is reused multiple times with each succes sive analysis being influenced by the outcomes of prior analyses. Other methods for proving gener alization include compression schemes and uniform stability. Unfortunately, these different methods for providing gener alization guarantees are largely disconnected from one another; it is, in general, not possible t o compare or combine techniques. In this paper, we provide a framework to reason about many of the se these differing approaches using the unifying language of information theory.