Fault Detection for Systems with Multiple Unknown Modes and Similar Units

This dissertation considers fault detection for large-scale practical systems with many nearly identical units operating in a shared environment. A special class of hybrid system model is introduced to describe such multi-unit systems, and a general approach for estimation and change detection is proposed. A novel fault detection algorithm is developed based on estimating a common Gaussian-mixture distribution for unit parameters whereby observations are mapped into a common parameter-space and clusters are then identified corresponding to different modes of operation via the Expectation- Maximization algorithm. The estimated common distribution incorporates and generalizes information from all units and is utilized for fault detection in each individual unit. The proposed algorithm takes into account unit mode switching, parameter drift, and can handle sudden, incipient, and preexisting faults. It can be applied to fault detection in various industrial, chemical, or manufacturing processes, sensor networks, and others. Several illustrative examples are presented, and a discussion on the pros and cons of the proposed methodology is provided. The proposed algorithm is applied specifically to fault detection in Heating Ventilation and Air Conditioning (HVAC) systems. Reliable and timely fault detection is a significant (and still open) practical problem in the HVAC industry { commercial buildings waste an estimated 15% to 30% ($20.8B -$41.61B annually) of their energy due to degraded, improperly controlled, or poorly maintained equipment. Results are presented from an extensive performance study based on both Monte Carlo simulations as well as real data collected from three operational large HVAC systems. The results demonstrate the capabilities of the new methodology in a more realistic setting and provide insights that can facilitate the design and implementation of practical fault detection for systems of similar type in other industrial applications

A novel algorithm and hardware architecture for fast video-based shape reconstruction of space debris

In order to enable the non-cooperative rendezvous, capture, and removal of large space debris, automatic recognition of the target is needed. Video-based techniques are the most suitable in the strict context of space missions, where low-energy consumption is fundamental, and sensors should be passive in order to avoid any possible damage to external objects as well as to the chaser satellite. This paper presents a novel fast shape-from-shading (SfS) algorithm and a field-programmable gate array (FPGA)-based system hardware architecture for video-based shape reconstruction of space debris. The FPGA-based architecture, equipped with a pair of cameras, includes a fast image pre-processing module, a core implementing a feature-based stereo-vision approach, and a processor that executes the novel SfS algorithm. Experimental results show the limited amount of logic resources needed to implement the proposed architecture, and the timing improvements with respect to other state-of-the-art SfS methods. The remaining resources available in the FPGA device can be exploited to integrate other vision-based techniques to improve the comprehension of debris model, allowing a fast evaluation of associated kinematics in order to select the most appropriate approach for capture of the target space debris

Collaborative Reuse of Streaming Dataflows in IoT Applications

Distributed Stream Processing Systems (DSPS) like Apache Storm and Spark Streaming enable composition of continuous dataflows that execute persistently over data streams. They are used by Internet of Things (IoT) applications to analyze sensor data from Smart City cyber-infrastructure, and make active utility management decisions. As the ecosystem of such IoT applications that leverage shared urban sensor streams continue to grow, applications will perform duplicate pre-processing and analytics tasks. This offers the opportunity to collaboratively reuse the outputs of overlapping dataflows, thereby improving the resource efficiency. In this paper, we propose \emph{dataflow reuse algorithms} that given a submitted dataflow, identifies the intersection of reusable tasks and streams from a collection of running dataflows to form a \emph{merged dataflow}. Similar algorithms to unmerge dataflows when they are removed are also proposed. We implement these algorithms for the popular Apache Storm DSPS, and validate their performance and resource savings for 35 synthetic dataflows based on public OPMW workflows with diverse arrival and departure distributions, and on 21 real IoT dataflows from RIoTBench.Comment: To appear in IEEE eScience Conference 201

Distribution and growth styles of isolated carbonate platforms as a function of fault propagation

Fault control on the position and distribution of isolated carbonate platforms is investigated in Northwest Australia using high-quality 3D seismic and borehole data from the Bonaparte Basin. Specifically, we address the relationship between carbonate productivity and fault growth so as to understand what are the primary controls on the growth of isolated carbonate platforms. Throw-depth (T-Z) and throw-distance (T-D) profiles for normal faults suggest they formed fault segments that were linked at different times in the study area. This caused differential vertical movements; some of the normal faults propagated to the surface, while others have upper tips that are 19–530 ms two-way-time below the sea floor, with the largest throw values comprising faults underneath isolated carbonate platforms. As a result, four distinct zones correlate with variable geometries and sizes of carbonate platforms, which are a function of the topographic relief generated by underlying propagating faults. Some relay ramps form the preferred location for the initiation and development of carbonate platforms, together with adjacent structural highs. Due to the complex effect of fault propagation to the palaeo-seafloor, and soft-linkage through relay ramps, three distinct ICP types are proposed: (1) in the first type, fault throw is larger than carbonate productivity; (2) the second type considers fault throw to be equal or less than carbonate productivity; and (3) in the third type, fault throw post-dates the growth of the carbonate platform(s). The analysis of fault propagation vs. carbonate platform growth shown here is important, as the three ICP types proposed, potentially correlate with variable fracture densities and distributions within the carbonate platforms. Based on our results, types 2 and 3 above enhance fracture- and fault-dominated porosity and permeability to a greater degree, making them favourable targets for hydrocarbon exploration

Scalable, Data- intensive Network Computation

To enable groups of collaborating researchers at different locations to effectively share large datasets and investigate their spontaneous hypotheses on the fly, we are interested in de- veloping a distributed system that can be easily leveraged by a variety of data intensive applications. The system is composed of (i) a number of best effort logistical depots to en- able large-scale data sharing and in-network data processing, (ii) a set of end-to-end tools to effectively aggregate, manage and schedule a large number of network computations with attendant data movements, and (iii) a Distributed Hash Table (DHT) on top of the generic depot services for scalable data management. The logistical depot is extended by following the end-to-end principles and is modeled with a closed queuing network model. Its performance characteristics are studied by solving the steady state distributions of the model using local balance equations. The modeling results confirm that the wide area network is the performance bottleneck and running concurrent jobs can increase resource utilization and system throughput. As a novel contribution, techniques to effectively support resource demanding data- intensive applications using the ¯ne-grained depot services are developed. These techniques include instruction level scheduling of operations, dynamic co-scheduling of computation and replication, and adaptive workload control. Experiments in volume visualization have proved the effectiveness of these techniques. Due to the unique characteristic of data- intensive applications and our co-scheduling algorithm, a DHT is implemented on top of the basic storage and computation services. It demonstrates the potential of the Logistical Networking infrastructure to serve as a service creation platform

UAV or Drones for Remote Sensing Applications in GPS/GNSS Enabled and GPS/GNSS Denied Environments

The design of novel UAV systems and the use of UAV platforms integrated with robotic sensing and imaging techniques, as well as the development of processing workflows and the capacity of ultra-high temporal and spatial resolution data, have enabled a rapid uptake of UAVs and drones across several industries and application domains.This book provides a forum for high-quality peer-reviewed papers that broaden awareness and understanding of single- and multiple-UAV developments for remote sensing applications, and associated developments in sensor technology, data processing and communications, and UAV system design and sensing capabilities in GPS-enabled and, more broadly, Global Navigation Satellite System (GNSS)-enabled and GPS/GNSS-denied environments.Contributions include:UAV-based photogrammetry, laser scanning, multispectral imaging, hyperspectral imaging, and thermal imaging;UAV sensor applications; spatial ecology; pest detection; reef; forestry; volcanology; precision agriculture wildlife species tracking; search and rescue; target tracking; atmosphere monitoring; chemical, biological, and natural disaster phenomena; fire prevention, flood prevention; volcanic monitoring; pollution monitoring; microclimates; and land use;Wildlife and target detection and recognition from UAV imagery using deep learning and machine learning techniques;UAV-based change detection