Performance Analysis
Statistical Bootstrapping for Uncertainty Estimation in Off-Policy Evaluation
In reinforcement learning, it is typical to use the empirically observed transitions and rewards to estimate the value of a policy via either model-based or Q-fitting approaches. Although straightforward, these techniques in general yield biased estimates of the true value of the policy. In this work, we investigate the potential for statistical bootstrapping to be used as a way to take these biased estimates and produce calibrated confidence intervals for the true value of the policy. We identify conditions - specifically, sufficient data size and sufficient coverage - under which statistical bootstrapping in this setting is guaranteed to yield correct confidence intervals. In practical situations, these conditions often do not hold, and so we discuss and propose mechanisms that can be employed to mitigate their effects. We evaluate our proposed method and show that it can yield accurate confidence intervals in a variety of conditions, including challenging continuous control environments and small data regimes.
Cyber Threat Intelligence for Secure Smart City
Al-Taleb, Najla, Saqib, Nazar Abbas, Atta-ur-Rahman, null, Dash, Sujata
Smart city improved the quality of life for the citizens by implementing information communication technology (ICT) such as the internet of things (IoT). Nevertheless, the smart city is a critical environment that needs to secure it is network and data from intrusions and attacks. This work proposes a hybrid deep learning (DL) model for cyber threat intelligence (CTI) to improve threats classification performance based on convolutional neural network (CNN) and quasi-recurrent neural network (QRNN). We use QRNN to provide a real-time threat classification model. The evaluation results of the proposed model compared to the state-of-the-art models show that the proposed model outperformed the other models. Therefore, it will help in classifying the smart city threats in a reasonable time.
Bounded Fuzzy Possibilistic Method of Critical Objects Processing in Machine Learning
Unsatisfying accuracy of learning methods is mostly caused by omitting the influence of important parameters such as membership assignments, type of data objects, and distance or similarity functions. The proposed method, called Bounded Fuzzy Possibilistic Method (BFPM) addresses different issues that previous clustering or classification methods have not sufficiently considered in their membership assignments. In fuzzy methods, the object's memberships should sum to 1. Hence, any data object may obtain full membership in at most one cluster or class. Possibilistic methods relax this condition, but the method can be satisfied with the results even if just an arbitrary object obtains the membership from just one cluster, which prevents the objects' movement analysis. Whereas, BFPM differs from previous fuzzy and possibilistic approaches by removing these restrictions. Furthermore, BFPM provides the flexible search space for objects' movement analysis. Data objects are also considered as fundamental keys in learning methods, and knowing the exact type of objects results in providing a suitable environment for learning algorithms. The Thesis introduces a new type of object, called critical, as well as categorizing data objects into two different categories: structural-based and behavioural-based. Critical objects are considered as causes of miss-classification and miss-assignment in learning procedures. The Thesis also proposes new methodologies to study the behaviour of critical objects with the aim of evaluating objects' movements (mutation) from one cluster or class to another. The Thesis also introduces a new type of feature, called dominant, that is considered as one of the causes of miss-classification and miss-assignments. Then the Thesis proposes new sets of similarity functions, called Weighted Feature Distance (WFD) and Prioritized Weighted Feature Distance (PWFD).
Deep Learning for Neuroimaging-based Diagnosis and Rehabilitation of Autism Spectrum Disorder: A Review
Khodatars, Marjane, Shoeibi, Afshin, Ghassemi, Navid, Jafari, Mahboobeh, Khadem, Ali, Sadeghi, Delaram, Moridian, Parisa, Hussain, Sadiq, Alizadehsani, Roohallah, Zare, Assef, Khosravi, Abbas, Nahavandi, Saeid, Acharya, U. Rajendra, Berk, Michael
Accurate diagnosis of Autism Spectrum Disorder (ASD) is essential for its management and rehabilitation. Neuroimaging techniques that are non-invasive are disease markers and may be leveraged to aid ASD diagnosis. Structural and functional neuroimaging techniques provide physicians substantial information about the structure (anatomy and structural connectivity) and function (activity and functional connectivity) of the brain. Due to the intricate structure and function of the brain, diagnosing ASD with neuroimaging data without exploiting artificial intelligence (AI) techniques is extremely challenging. AI techniques comprise traditional machine learning (ML) approaches and deep learning (DL) techniques. Conventional ML methods employ various feature extraction and classification techniques, but in DL, the process of feature extraction and classification is accomplished intelligently and integrally. In this paper, studies conducted with the aid of DL networks to distinguish ASD were investigated. Rehabilitation tools provided by supporting ASD patients utilizing DL networks were also assessed. Finally, we presented important challenges in this automated detection and rehabilitation of ASD.
Interesting AI/ML Articles You Should Read This Week (July 4)
This week I came across several articles that challenge the development and utilization of AI-based system across several domains. This week I came across several articles that challenge the development and utilization of AI-based system across several domains. I've never had to genuinely reflect on the philosophical and legal aspects of my contributions as a machine learning practitioner, but this has changed after reading some interesting articles that present the consequences of AI advancement that are happening now, and those that are yet to happen. Our lives today could look entirely different tomorrow. Would you let a machine learning model that has a failure rate of 98% and a false positive rate of 81% into production?
A Novel Approach to the Diagnosis of Heart Disease using Machine Learning and Deep Neural Networks
Heart disease is the leading cause of death worldwide. Currently, 33% of cases are misdiagnosed, and approximately half of myocardial infarctions occur in people who are not predicted to be at risk. The use of Artificial Intelligence could reduce the chance of error, leading to possible earlier diagnoses, which could be the difference between life and death for some. The objective of this project was to develop an application for assisted heart disease diagnosis using Machine Learning (ML) and Deep Neural Network (DNN) algorithms. The dataset was provided from the Cleveland Clinic Foundation, and the models were built based on various optimization and hyper parametrization techniques including a Grid Search algorithm. The application, running on Flask, and utilizing Bootstrap was developed using the DNN, as it performed higher than the Random Forest ML model with a total accuracy rate of 92%.
Neural Network Verification through Replication
Sanchirico, Mauro J. III, Jiao, Xun, Nataraj, C.
A system identification based approach to neural network model replication is presented and the application of model replication to verification of fundamental, single hidden layer, neural network systems is demonstrated. The presented approach serves as a means to partially address the problem of verifying that a neural network implementation meets a provided specification given only grey-box access to the implemented network. The procedure developed involves stimulating a neural network with a chosen signal, extracting a replicated model from the response, and systematically checking that the replicated model is output-equivalent to a specified model in order to verify that the grey-box system under test is implemented to specification without direct access to its hidden parameters. The replication step is introduced to provide an inherent guarantee that the stimulus signals employed yield sufficient test coverage. This method is investigated as a neural network focused nonlinear counterpart to the traditional verification of circuits through system identification. A strategy for choosing the stimulus is provided and an algorithm for verifying that the resulting response is indicative of a specification-compliant neural network system under test is derived. We find that the method can reliably detect defects in small neural networks or in small sub-circuits within larger neural networks.
Approximately Optimal Binning for the Piecewise Constant Approximation of the Normalized Unexplained Variance (nUV) Dissimilarity Measure
Fazekas, Attila, Kovács, György
The recently introduced Matching by Tone Mapping (MTM) dissimilarity measure enables template matching under smooth non-linear distortions and also has a well-established mathematical background. MTM operates by binning the template, but the ideal binning for a particular problem is an open question. By pointing out an important analogy between the well known mutual information (MI) and MTM, we introduce the term "normalized unexplained variance" (nUV) for MTM to emphasize its relevance and applicability beyond image processing. Then, we provide theoretical results on the optimal binning technique for the nUV measure and propose algorithms to find approximate solutions. The theoretical findings are supported by numerical experiments. Using the proposed techniques for binning shows 4-13% increase in terms of AUC scores with statistical significance, enabling us to conclude that the proposed binning techniques have the potential to improve the performance of the nUV measure in real applications.