Generalisable FPCA-based Models for Predicting Peak Power in Vertical Jumping using Accelerometer Data

Peak power in the countermovement jump is correlated with various measures of sports performance and can be used to monitor athlete training. The gold standard method for determining peak power uses force platforms, but they are unsuitable for field-based testing favoured by practitioners. Alternatives include predicting peak power from jump flight times, or using Newtonian methods based on body-worn inertial sensor data, but so far neither has yielded sufficiently accurate estimates. This thesis aims to develop a generalisable model for predicting peak power based on Functional Principal Component Analysis applied to body-worn accelerometer data. Data was collected from 69 male and female adults, engaged in sports at recreational, club or national levels. They performed up to 16 countermovement jumps each, with and without arm swing, 696 jumps in total. Peak power criterion measures were obtained from force platforms, and characteristic features from accelerometer data were extracted from four sensors attached to the lower back, upper back and both shanks. The best machine learning algorithm, jump type and sensor anatomical location were determined in this context. The investigation considered signal representation (resultant, triaxial or a suitable transform), preprocessing (smoothing, time window and curve registration), feature selection and data augmentation (signal rotations and SMOTER). A novel procedure optimised the model parameters based on Particle Swarm applied to a surrogate Gaussian Process model. Model selection and evaluation were based on nested cross validation (Monte Carlo design). The final optimal model had an RMSE of 2.5 W·kg-1, which compares favourably to earlier research (4.9 ± 1.7 W·kg-1 for flight-time formulae and 10.7 ± 6.3 W·kg-1 for Newtonian sensor-based methods). Whilst this is not yet sufficiently accurate for applied practice, this thesis has developed and comprehensively evaluated new techniques, which will be valuable to future biomechanical applications

Automatic and early detection of Parkinson’s Disease by analyzing acoustic signals using classification algorithms based on recursive feature elimination method

Parkinson’s disease (PD) is a neurodegenerative condition generated by the dysfunction of brain cells and their 60–80% inability to produce dopamine, an organic chemical responsible for controlling a person’s movement. This condition causes PD symptoms to appear. Diagnosis involves many physical and psychological tests and specialist examinations of the patient’s nervous system, which causes several issues. The methodology method of early diagnosis of PD is based on analysing voice disorders. This method extracts a set of features from a recording of the person’s voice. Then machine-learning (ML) methods are used to analyse and diagnose the recorded voice to distinguish Parkinson’s cases from healthy ones. This paper proposes novel techniques to optimize the techniques for early diagnosis of PD by evaluating selected features and hyperparameter tuning of ML algorithms for diagnosing PD based on voice disorders. The dataset was balanced by the synthetic minority oversampling technique (SMOTE) and features were arranged according to their contribution to the target characteristic by the recursive feature elimination (RFE) algorithm. We applied two algorithms, t-distributed stochastic neighbour embedding (t-SNE) and principal component analysis (PCA), to reduce the dimensions of the dataset. Both t-SNE and PCA finally fed the resulting features into the classifiers support-vector machine (SVM), K-nearest neighbours (KNN), decision tree (DT), random forest (RF), and multilayer perception (MLP). Experimental results proved that the proposed techniques were superior to existing studies in which RF with the t-SNE algorithm yielded an accuracy of 97%, precision of 96.50%, recall of 94%, and F1-score of 95%. In addition, MLP with the PCA algorithm yielded an accuracy of 98%, precision of 97.66%, recall of 96%, and F1-score of 96.66%

Advances in Computational Intelligence Applications in the Mining Industry

This book captures advancements in the applications of computational intelligence (artificial intelligence, machine learning, etc.) to problems in the mineral and mining industries. The papers present the state of the art in four broad categories: mine operations, mine planning, mine safety, and advances in the sciences, primarily in image processing applications. Authors in the book include both researchers and industry practitioners

Machine learning for human-centered and value-sensitive building energy efficiency

Enhancing building energy efficiency is one of the best strategies to reduce energy consumption and associated CO2 emissions. Recent studies emphasized the importance of occupant behavior as a key means of enhancing building energy efficiency. However, it is also critical that while we strive to enhance the energy efficiency of buildings through improving occupant behavior, we still pay enough attention to occupant comfort and satisfaction. Towards this goal, this research proposes a data-driven machine-learning-based approach to behavioral building energy efficiency, which could help better understand and predict the impact of occupant behavior on building energy consumption and occupant comfort; and help optimize occupant behavior for both energy saving and occupant comfort. Three types of models were developed and tested – simulation-data-driven, real-data-driven, and hybrid. Accordingly, the research included five primary research tasks. First, the importance levels of energy-related human values (e.g., thermal comfort) to building occupants and their current satisfaction levels with these values were identified, in order to better understand the factors that are associated with higher/lower importance and/or satisfaction levels and identify the potential factors that could help predict occupant comfort. Second, a data sensing and occupant feedback collection plan was developed, in order to capture and monitor the indoor environmental conditions, energy consumption, energy-related occupant behavior, and occupant comfort in real buildings. Third, a set of buildings were simulated, in order to model the energy consumption of different buildings in different contexts – in terms of occupant behavior, building sizes, weather conditions, etc.; and a simulation-data-driven occupant-behavior-sensitive machine learning-based model, which learns from simulation data, was developed for predicting hourly cooling energy consumption. Fourth, a set of real-data-driven occupant-behavior-sensitive machine learning-based models, which learn from real data (data collected from real buildings and real occupants), were developed for predicting hourly cooling and lighting energy consumption and thermal and visual occupant comfort; and a genetic algorithm-based optimization model for determining the optimal occupant behavior that can simultaneously reduce energy consumption and improve occupant comfort was developed. Compared to the simulation-data-driven approach, the real-data-driven approach aims to better capture and model the real-life behavior and comfort of occupants and the real-life energy-consumption patterns of buildings. Although successful in this regard, the resulting models may not generalize well outside of their training range. Fifth, a hybrid, occupant-behavior-sensitive machine learning-based model, which learns from both simulation data and real data, was developed for predicting hourly cooling and lighting energy consumption. The hybrid approach aims to overcome the limitations of both simulation-data-driven and real-data-driven approaches – especially the limited ability to capture occupant behavior and real-life consumption patterns in simulation-data-driven approaches and the limited generalizability of real-data-driven approaches to different cases – by learning from both types of data simultaneously. The experimental results show the potential of the proposed approach. The energy consumption prediction models achieved high prediction performance, and the thermal and visual comfort models were able to accurately represent the individual and group comfort levels. The optimization results showed potential behavioral energy savings in the range of 11% and 22%, with significant improvement in occupant comfort

Report of the Benthos Ecology Working Group (BEWG) [2–6 May 2011 Fort Pierce, USA]

Contributors: Lene Buhl-Mortense

Developing and Applying CAD-generated Image Markers to Assist Disease Diagnosis and Prognosis Prediction

Developing computer-aided detection and/or diagnosis (CAD) schemes has been an active research topic in medical imaging informatics (MII) with promising results in assisting clinicians in making better diagnostic and/or clinical decisions in the last two decades. To build robust CAD schemes, we need to develop state-of-the-art image processing and machine learning (ML) algorithms to optimize each step in the CAD pipeline, including detection and segmentation of the region of interest, optimal feature generation, followed by integration to ML classifiers. In my dissertation, I conducted multiple studies investigating the feasibility of developing several novel CAD schemes in the field of medicine concerning different purposes. The first study aims to investigate how to optimally develop a CAD scheme of contrast-enhanced digital mammography (CEDM) images to classify breast masses. CEDM includes both low energy (LE) and dual-energy subtracted (DES) images. A CAD scheme was applied to segment mass regions depicting LE and DES images separately. Optimal segmentation results generated from DES images were also mapped to LE images or vice versa. After computing image features, multilayer perceptron-based ML classifiers integrated with a correlation-based feature subset evaluator and leave-one-case-out cross-validation method were built to classify mass regions. The study demonstrated that DES images eliminated the overlapping effect of dense breast tissue, which helps improve mass segmentation accuracy. By mapping mass regions segmented from DES images to LE images, CAD yields significantly improved performance. The second study aims to develop a new quantitative image marker computed from the pre-intervention computed tomography perfusion (CTP) images and evaluate its feasibility to predict clinical outcome among acute ischemic stroke (AIS) patients undergoing endovascular mechanical thrombectomy after diagnosis of large vessel occlusion. A CAD scheme is first developed to pre-process CTP images of different scanning series for each study case, perform image segmentation, quantify contrast-enhanced blood volumes in bilateral cerebral hemispheres, and compute image features related to asymmetrical cerebral blood flow patterns based on the cumulative cerebral blood flow curves of two hemispheres. Next, image markers based on a single optimal feature and ML models fused with multi-features are developed and tested to classify AIS cases into two classes of good and poor prognosis based on the Modified Rankin Scale. The study results show that ML model trained using multiple features yields significantly higher classification performance than the image marker using the best single feature (p<0.01). This study demonstrates the feasibility of developing a new CAD scheme to predict the prognosis of AIS patients in the hyperacute stage, which has the potential to assist clinicians in optimally treating and managing AIS patients. The third study aims to develop and test a new CAD scheme to predict prognosis in aneurysmal subarachnoid hemorrhage (aSAH) patients using brain CT images. Each patient had two sets of CT images acquired at admission and prior to discharge. CAD scheme was applied to segment intracranial brain regions into four subregions, namely, cerebrospinal fluid (CSF), white matter (WM), gray matter (GM), and extraparenchymal blood (EPB), respectively. CAD then computed nine image features related to 5 volumes of the segmented sulci, EPB, CSF, WM, GM, and four volumetrical ratios to sulci. Subsequently, 16 ML models were built using multiple features computed either from CT images acquired at admission or prior to discharge to predict eight prognosis related parameters. The results show that ML models trained using CT images acquired at admission yielded higher accuracy to predict short-term clinical outcomes, while ML models trained using CT images acquired prior to discharge had higher accuracy in predicting long-term clinical outcomes. Thus, this study demonstrated the feasibility of predicting the prognosis of aSAH patients using new ML model-generated quantitative image markers. The fourth study aims to develop and test a new interactive computer-aided detection (ICAD) tool to quantitatively assess hemorrhage volumes. After loading each case, the ICAD tool first segments intracranial brain volume, performs CT labeling of each voxel. Next, contour-guided image-thresholding techniques based on CT Hounsfield Unit are used to estimate and segment hemorrhage-associated voxels (ICH). Next, two experienced neurology residents examine and correct the markings of ICH categorized into either intraparenchymal hemorrhage (IPH) or intraventricular hemorrhage (IVH) to obtain the true markings. Additionally, volumes and maximum two-dimensional diameter of each sub-type of hemorrhage are also computed for understanding ICH prognosis. The performance to segment hemorrhage regions between semi-automated ICAD and the verified neurology residents’ true markings is evaluated using dice similarity coefficient (DSC). The data analysis results in the study demonstrate that the new ICAD tool enables to segment and quantify ICH and other hemorrhage volumes with higher DSC. Finally, the fifth study aims to bridge the gap between traditional radiomics and deep learning systems by comparing and assessing these two technologies in classifying breast lesions. First, one CAD scheme is applied to segment lesions and compute radiomics features. In contrast, another scheme applies a pre-trained residual net architecture (ResNet50) as a transfer learning model to extract automated features. Next, the principal component algorithm processes both initially computed radiomics and automated features to create optimal feature vectors. Then, several support vector machine (SVM) classifiers are built using the optimized radiomics or automated features. This study indicates that (1) CAD built using only deep transfer learning yields higher classification performance than the traditional radiomic-based model, (2) SVM trained using the fused radiomics and automated features does not yield significantly higher AUC, and (3) radiomics and automated features contain highly correlated information in lesion classification. In summary, in all these studies, I developed and investigated several key concepts of CAD pipeline, including (i) pre-processing algorithms, (ii) automatic detection and segmentation schemes, (iii) feature extraction and optimization methods, and (iv) ML and data analysis models. All developed CAD models are embedded with interactive and visually aided graphical user interfaces (GUIs) to provide user functionality. These techniques present innovative approaches for building quantitative image markers to build optimal ML models. The study results indicate the underlying CAD scheme's potential application to assist radiologists in clinical settings for their assessments in diagnosing disease and improving their overall performance

Fisher networks: A principled approach to retrieval-based classification

Due to the technological advances in the acquisition and processing of information, current data mining applications involve databases of sizes that would be unthinkable just two decades ago. However, real-word datasets are often riddled with irrelevant variables that not only do not generate any meaningful information about the process of interest, but may also obstruct the contribution of the truly informative data features. Taking into consideration the relevance of the different measures available can make the difference between reaching an accurate reflection of the underlying truth and obtaining misleading results that cause the drawing of erroneousconclusions. Another important consideration in data analysis is the interpretability of the models used to fit the data. It is clear that performance must be a key aspect in deciding which methodology to use, but it should not be the only one. Models with an obscure internal operation see their practical usefulness effectively diminished by the difficulty to understand the reasoning behind their inferences, which makes them less appealing to users that are not familiar with their theoretical basis. This thesis proposes a novel framework for the visualisation and categorisation of data in classification contexts that tackles the two issues discussed above and provides an informative output of intuitive interpretation. The system is based on a Fisher information metric that automatically filters the contribution of variables depending on their relevance with respect to the classification problem at hand, measured by their influence on the posterior class probabilities. Fisher distances can then be used to calculate rigorous problem-specific similarity measures, which can be grouped into a pairwise adjacency matrix, thus defining a network. Following this novel construction process results in a principled visualisation of the data organised in communities that highlights the structure of the underlying class membership probabilities. Furthermore, the relational nature of the network can be used to reproduce the probabilistic predictions of the original estimates in a case-based approach, making them explainable by means of known cases in the dataset. The potential applications and usefulness of the framework are illustrated using several real-world datasets, giving examples of the typical output that the end user receives and how they can use it to learn more about the cases of interest as well as about the dataset as a whole

Detection of Anomalous Behavior of IoT/CPS Devices Using Their Power Signals

Embedded computing devices, in the Internet of Things (IoT) or Cyber-Physical Systems (CPS), are becoming pervasive in many domains around the world. Their wide deployment in simple applications (e.g., smart buildings, fleet management, and smart agriculture) or in more critical operations (e.g., industrial control, smart power grids, and self-driving cars) creates significant market potential ($ 4-11 trillion in annual revenue is expected by 2025). A main requirement for the success of such systems and applications is the capacity to ensure the performance of these devices. This task includes equipping them to be resilient against security threats and failures. Globally, several critical infrastructure applications have been the target of cyber attacks. These recent incidents, as well as the rich applicable literature, confirm that more research is needed to overcome such challenges. Consequently, the need for robust approaches that detect anomalous behaving devices in security and safety-critical applications has become paramount. Solving such a problem minimizes different kinds of losses (e.g., confidential data theft, financial loss, service access restriction, or even casualties). In light of the aforementioned motivation and discussion, this thesis focuses on the problem of detecting the anomalous behavior of IoT/CPS devices by considering their side-channel information. Solving such a problem is extremely important in maintaining the security and dependability of critical systems and applications. Although several side-channel based approaches are found in the literature, there are still important research gaps that need to be addressed. First, the intrusive nature of the monitoring in some of the proposed techniques results in resources overhead and requires instrumentation of the internal components of a device, which makes them impractical. It also raises a data integrity flag. Second, the lack of realistic experimental power consumption datasets that reflect the normal and anomalous behaviors of IoT and CPS devices has prevented fair and coherent comparisons with the state of the art in this domain. Finally, most of the research to date has concentrated on the accuracy of detection and not the novelty of detecting new anomalies. Such a direction relies on: (i) the availability of labeled datasets; (ii) the complexity of the extracted features; and (iii) the available compute resources. These assumptions and requirements are usually unrealistic and unrepresentative. This research aims to bridge these gaps as follows. First, this study extends the state of the art that adopts the idea of leveraging the power consumption of devices as a signal and the concept of decoupling the monitoring system and the devices to be monitored to detect and classify the "operational health'' of the devices. Second, this thesis provides and builds power consumption-based datasets that can be utilized by AI as well as security research communities to validate newly developed detection techniques. The collected datasets cover a wide range of anomalous device behavior due to the main aspects of device security (i.e., confidentiality, integrity, and availability) and partial system failures. The extensive experiments include: a wide spectrum of various emulated malware scenarios; five real malware applications taken from the well-known Drebin dataset; distributed denial of service attack (DDOS) where an IoT device is treated as: (1) a victim of a DDOS attack, and (2) the source of a DDOS attack; cryptomining malware where the resources of an IoT device are being hijacked to be used to advantage of the attacker’s wish and desire; and faulty CPU cores. This level of extensive validation has not yet been reported in any study in the literature. Third, this research presents a novel supervised technique to detect anomalous device behavior based on transforming the problem into an image classification problem. The main aim of this methodology is to improve the detection performance. In order to achieve the goals of this study, the methodology combines two powerful computer vision tools, namely Histograms of Oriented Gradients (HOG) and a Convolutional Neural Network (CNN). Such a detection technique is not only useful in this present case but can contribute to most time-series classification (TSC) problems. Finally, this thesis proposes a novel unsupervised detection technique that requires only the normal behavior of a device in the training phase. Therefore, this methodology aims at detecting new/unseen anomalous behavior. The methodology leverages the power consumption of a device and Restricted Boltzmann Machine (RBM) AutoEncoders (AE) to build a model that makes them more robust to the presence of security threats. The methodology makes use of stacked RBM AE and Principal Component Analysis (PCA) to extract feature vector based on AE's reconstruction errors. A One-Class Support Vector Machine (OC-SVM) classifier is then trained to perform the detection task. Across 18 different datasets, both of our proposed detection techniques demonstrated high detection performance with at least ~ 88% accuracy and 85% F-Score on average. The empirical results indicate the effectiveness of the proposed techniques and demonstrated improved detection performance gain of 9% - 17% over results reported in other methods