Collective Contextual Anomaly Detection for Building Energy Consumption

Commercial and residential buildings are responsible for a substantial portion of total global energy consumption and as a result make a significant contribution to global carbon emissions. Hence, energy-saving goals that target buildings can have a major impact in reducing environmental damage. During building operation, a significant amount of energy is wasted due to equipment and human-related faults. To reduce waste, today\u27s smart buildings monitor energy usage with the aim of identifying abnormal consumption behaviour and notifying the building manager to implement appropriate energy-saving procedures. To this end, this research proposes the \textit{ensemble anomaly detection} (EAD) framework. The EAD is a generic framework that combines several anomaly detection classifiers using majority voting. This anomaly detection classifiers are formed using existing machine learning algorithm. It is assumed that each anomaly classifier has equal weight. More importantly, to ensure diversity of anomaly classifiers, the EAD is implemented by combining pattern-based and prediction-based anomaly classifiers. For this reason, this research also proposes a new pattern-based anomaly classifier, the \textit{collective contextual anomaly detection using sliding window} (CCAD-SW) framework. The CCAD-SW, which is also a machine leaning-based framework that identifies anomalous consumption patterns using overlapping sliding windows. The EAD framework combines the CCAD-SW, which is implemented using autoencoder, with two prediction-based anomaly classifiers that are implemented using the support vector regression and random forest machine-learning algorithms. In addition, it determines an ensemble threshold that yields an anomaly classifier with optimal anomaly detection capability and false positive minimization. Results show that the EAD performs better than the individual anomaly detection classifiers. In the EAD framework, the optimal ensemble anomaly classifier is not attained by combining the individual learners at their respective optimal performance levels. Instead, an ensemble threshold combination that yields the optimal anomaly classifier was identified by searching through the ensemble threshold space. The research was evaluated using real-world data provided by Powersmiths, located in Brampton, Ontario, Canada

ICT, open government and civil society

Abstract This paper explores the rise of ICTs as instruments of government reform and the implication of their use from the vantage point of the relations between democratic governance, the aims of Buen Vivir, and the role of civil society. We discuss some of the contradictions inherent in the nature and organisation of ICTs, particularly in connection to such e-government projects as “smart cities” and participatory budgeting, and focus on the centrality of social relationships, political agency and the operations of social capital as elements that determine the success of these initiatives in the promotion of democratic practice. We also examine the relevance of social capital and user control to organisational structure and the ways in which structure relates to social innovation and the access, transfer and diffusion of knowledge as a common good. The paper concludes with a discussion of the significance of ICTs as instruments of civil empowerment and introduces the notion of “generative democracy” as a means of re-imagining and realigning the role and powers of the state and civil society for the social production of goods and services

The Impact of Artificial Intelligence on Military Defence and Security

The twenty-first century is now being shaped by a multipolar system characterized by techno-nationalism and a post-Bretton Woods order. In the face of a rapidly evolving digital era, international cooperation will be critical to ensuring peace and security. Information sharing, expert conferences and multilateral dialogue can help the world's nation-states and their militaries develop a better understanding of one another's capabilities and intentions. As a global middle power, Canada could be a major partner in driving this effort. This paper explores the development of military-specific capabilities in the context of artificial intelligence (AI) and machine learning. Building on Canadian defence policy, the paper outlines the military applications of AI and the resources needed to manage next-generation military operations, including multilateral engagement and technology governance

Vertical axis wind turbine in a falling soap film

Vertical axis wind turbines (VAWTs) have demonstrated a potential to significantly enhance the efficiency of energy harvesting within a wind farm. One mechanism that contributes to this enhancement is a VAWT’s inherent insensitivity to wind direction coupled with blockage within an array of turbines. Much like the flow around a bluff body, turbine blockage can locally accelerate the flow near one turbine, providing faster inflow conditions for a well-placed neighboring turbine. Since the power produced by a VAWT typically scales as the cube of the incoming wind speed, even a modest acceleration of the flow can have a significant impact on the overall turbine array performance

La descentralización de la práctica evaluativa orientada al autoaprendizaje del estudiante

El presente artículo tiene por objetivo analizar la descentralización evaluativa como una práctica democratizadora orientada a la participación y al fortalecimiento de los aprendizajes de los estudiantes. Desde una perspectiva interpretativa, se realiza una selección de la literatura especializada, considerando como criterios de revisión el rol de los agentes evaluativos, la autorregulación del aprendizaje y la descentralización evaluativa. El argumento central sostiene que la descentralización evaluativa consolida las prácticas reflexivas, críticas y autocríticas asociadas a los procesos de aprendizaje. Se concluye que es fundamental consolidar procedimientos de autoevaluación, coevaluación y evaluación de pares, con la finalidad de construir una evaluación como un espacio de negociación de significados e intersubjetividades que contribuyen a la creación de una cultura evaluativa focalizada en el progreso de los aprendizajes significativos y en la construcción de un estudiante más consciente de sí mismo

Turbulence in vertical axis wind turbine canopies

Experimental results from three different full scale arrays of vertical-axis wind turbines (VAWTs) under natural wind conditions are presented. The wind velocities throughout the turbine arrays are measured using a portable meteorological tower with seven, vertically staggered, three-component ultrasonic anemometers. The power output of each turbine is recorded simultaneously. The comparison between the horizontal and vertical energy transport for the different turbine array sizes shows the importance of vertical transport for large array configurations. Quadrant-hole analysis is employed to gain a better understanding of the vertical energy transport at the top of the VAWT arrays. The results show a striking similarity between the flows in the VAWT arrays and the adjustment region of canopies. Namely, an increase in ejections and sweeps and decrease in inward and outward interactions occur inside the turbine array. Ejections are the strongest contributor, which is in agreement with the literature on evolving and sparse canopy flows. The influence of the turbine array size on the power output of the downstream turbines is examined by comparing a streamwise row of four single turbines with square arrays of nine turbine pairs. The results suggest that a new boundary layer forms on top of the larger turbine arrays as the flow adjusts to the new roughness length. This increases the turbulent energy transport over the whole planform area of the turbine array. By contrast, for the four single turbines, the vertical energy transport due to turbulent fluctuations is only increased in the near wake of the turbines. These findings add to the knowledge of energy transport in turbine arrays and therefore the optimization of the turbine spacing in wind farms

Topological defects in a double-mirror quadrupole insulator displace diverging charge

We show that topological defects in quadrupole insulators do not host quantized fractional charges, contrary to what their Wannier representation indicates. In particular, we test the charge quantization hypothesis based on the Wannier representation of a parametric defect and a disclination. Against the expectations, we find that the local charge density decays as $\sim 1/r^2$ with distance, leading to a diverging defect charge. We identify sublattice symmetry and not higher order topology as the origin of the previously reported charge quantization.Comment: 7 pages, 3 figure

Agua, cultura y territorio.

Universidad Pablo de Olavide. Área de Historia del ArteVersión del edito

Resistive MHD Simulations of Laminar Round Jets with Application to Magnetic Nozzle Flows

This thesis investigates fundamental flows of resistive magnetohydrodynamics (MHD) by a new numerical tool based on the gas-kinetic method. The motivation for this work stems from the need to analyze the mechanisms of plasma detachment in the exhaust plume of the magnetoplasma rocket known as VASIMRR. This rocket has great potential for reducing the travel time for deep space exploration missions. However, it is very difficult to investigate detachment in ground-based experiments because this large-scale device can fully function only in a vacuum. This difficulty makes computational analysis and modeling an important part of the design and testing process. A parallelized Boltzmann-BGK continuum flow solver is expanded to include resistive MHD physics. This new code is validated against known solutions to MHD channel flows and new results are presented for simulations of a laminar round jet subject to a constant applied magnetic field as well as the diverging magnetic field of a current loop. Additionally, a parametric map is presented that outlines appropriate conditions required when using a fluid model for magnetic nozzle flows. The work of this thesis serves as an introductory step to developing a robust numerical ow solver capable of simulating magnetic nozzle flows and other plasmas that cannot be easily replicated in ground facilities

Aerodynamics of Vertical-axis Wind Turbines in Full-scale and Laboratory-scale Experiments

Within a wind farm, multiple turbine wakes can interact and have a substantial effect on the overall power production. This makes an understanding of the wake recovery process critically important to optimizing wind farm efficiency. Vertical-axis wind turbines (VAWTs) exhibit features that are amenable to dramatically improving this efficiency. However, the physics of the flow around VAWTs is not well understood, especially as it pertains to wake interactions, and it is the goal of this thesis to partially fill this void. This objective is approached from two broadly different perspectives: a low-order view of wind farm aerodynamics, and a detailed experimental analysis of the VAWT wake. One of the contributions of this thesis is the development of a semi-empirical model of wind farm aerodynamics, known as the LRB model, that is able to predict turbine array configurations to leading order accuracy. Another contribution is the characterization of the VAWT wake as a function of turbine solidity. It was found that three distinct regions of flow exist in the VAWT wake: (1) the near wake, where periodic blade shedding of vorticity dominates; (2) a transition region, where growth of a shear-layer instability occurs; (3) the far wake, where bluff-body oscillations dominate. The wake transition can be predicted using a new parameter, the dynamic solidity, which establishes a quantitative connection between the wake of a VAWT and that of a circular cylinder. The results provide insight into the mechanism of the VAWT wake recovery and the potential means to control it.</p