Understanding Person Identification Through Gait

Gait recognition is the process of identifying humans from their bipedal locomotion such as walking or running. As such, gait data is privacy sensitive information and should be anonymized where possible. With the rise of higher quality gait recording techniques, such as depth cameras or motion capture suits, an increasing amount of detailed gait data is captured and processed. Introduction and rise of the Metaverse is but one popular application scenario in which the gait of users is transferred onto digital avatars. As a first step towards developing effective anonymization techniques for high-quality gait data, we study different aspects of movement data to quantify their contribution to gait recognition. We first extract categories of features from the literature on human gait perception and then design experiments for each category to assess how much the information they contain contributes to recognition success. Our results show that gait anonymization will be challenging, as the data is highly redundant and interdependent

Social Media Analytics and Information Privacy Decisions: Impact of User Intimate Knowledge and Co-ownership Perceptions

Social media analytics has been recognized as a distinct research field in the analytics subdomain that is developed by processing social media content to generate important business knowledge. Understanding the factors that influence privacy decisions around its use is important as it is often perceived to be opaque and mismanaged. Social media users have been reported to have low intimate knowledge and co-ownership perception of social media analytics and its information privacy decisions. This deficiency leads them to perceive privacy violations if firms make privacy decisions that conflict with their expectations. Such perceived privacy violations often lead to business disruptions caused by user rebellions, regulatory interventions, firm reputation damage, and other business continuity threats. Existing research had developed theoretical frameworks for multi-level information privacy management and called for empirical testing of which constructs would increase user self-efficacy in negotiating with firms for joint social media analytics decision making. A response to this call was studied by measuring the constructs in the literature that lead to normative social media analytics and its information privacy decisions. The study model was developed by combining the relevant constructs from the theory of psychological ownership in organizations and the theory of multilevel information privacy. From psychological ownership theory, the impact that intimate knowledge had on co-ownership perception of social media analytics was added. From the theory of multi-level information privacy, the impact of co-ownership perception on the antecedents of information privacy decisions: the social identity assumed, and information privacy norms used were examined. In addition, the moderating role of the cost and benefits components of the privacy calculus on the relationship between information privacy norms and expected information privacy decisions was measured. A quantitative research approach was used to measure these factors. A web-based survey was developed using survey items obtained from prior studies that measured these constructs with only minor wording changes made. A pilot-study of 34 participants was conducted to test and finalize the instrument. The survey was distributed to adult social media users in the United States of America on a crowdsourcing marketplace using a commercial online survey service. 372 responses were accepted and analyzed. The partial least squares structural equation modeling method was used to assess the model and analyze the data using the Smart partial least squares 3 statistical software package. An increase in intimate knowledge of social media analytics led to higher co-ownership perception among social media users. Higher levels of co-ownership perception led to higher expectation of adoption of a salient social identity and higher expected information privacy norms. In addition, higher levels of expectation of social information privacy norm use led to normative privacy decisions. Higher levels of benefit estimation in the privacy calculus negatively moderated the relationship between social norms and privacy decision making. Co-ownership perception did not have a significant effect on the cost estimation in social media analytics privacy calculus. Similarly, the cost estimation in the privacy calculus did not have a significant effect on the relationship between information privacy norm adoption and the expectation of a normative information privacy decision. The findings of the study are a notable information systems literature contribution in both theory and practice. The study is one of the few to further develop multilevel information privacy theory by adding the intimate knowledge construct. The study model is a contribution to literature since its one of first to combine and validate elements of psychological ownership in organization theory to the theory of multilevel information privacy in order to understand what social media users expect when social media analytics information privacy decisions are made. The study also contributes by suggesting approaches practitioners can use to collaboratively manage their social media analytics information privacy decisions which was previously perceived to be opaque and under examined. Practical suggestions social media firms could use to decrease negative user affectations and engender deeper information privacy collaboration with users as they seek benefit from social media analytics were offered

Measurement-Based Monitoring and Control in Power Systems with High Renewable Penetrations

Power systems are experiencing rapid changes in their generation mixes because of the increasing integration of inverter-based resources (IBRs) and the retirement of traditional generations. This opens opportunities for a cleaner energy outlook but also poses challenges to the safe operation of the power networks. Enhanced monitoring and control based on the increasingly available measurements are essential in assisting stable operation and effective planning for these evolving systems. First, awareness of the evolving dynamic characteristics is quintessential for secure operation and corrective planning. A quantified monitoring study that keeps track of the inertial response and primary frequency response is conducted on the Eastern Interconnection (EI) for the past decade with field data. Whereas the inertia declined by at least 10%, the primary frequency response experienced an unexpected increase. The findings unveiled in the trending analysis also led to an improved event MW size estimation method, as well as discussions about regional dynamics. Experiencing a faster and deeper renewable integration, the Continental Europe Synchronous Area (CESA) system has been threatened by more frequent occurrences of inter-area oscillations during light-load high-renewable periods. A measurement-based oscillation damping control scheme is proposed for CESA with reduced reliance on system models. The design, implementation, and hardware-in-the-loop (HIL) testing of the controller are discussed in detail. Despite the challenges, the increasing presence of IBRs also brings opportunities for fast and efficient controls. Together with synchronized measurement, IBRs have the potential to flexibly complement traditional frequency and voltage control schemes for improved frequency and voltage recovery. The design, implementation, and HIL testing of the measurement-based frequency and voltage control for the New York State Grid are presented. In addition to the transmission level development, IBRs deployed in distribution networks can also be valuable assets in emergency islanding situations if controlled properly. A power management module is proposed to take advantage of measurements and automatically control the electric boundaries of islanded microgrids for maximized power utilization and improved frequency regulation. The module is designed to be adaptive to arbitrary non-meshed topologies with multiple source locations for increased flexibility, expedited deployment, and reduced cost

Data-driven coordination of assets in power distribution systems for ancillary service provision

In this dissertation, we develop several data-driven frameworks for coordinating distributed energy resources (DERs) in power distribution systems to provide ancillary services including active power provision and reactive power regulation. The proposed frameworks generally consist of three components, namely (i) an input-output (IO) model of the system describing the relation between the variables of interest to the problem, (ii) an estimator that provides estimates of the parameters that populate the model in (i), and (iii) a controller that uses the model in (i) with the parameters estimated via (ii) to determine the active and/or reactive power injection set-points of the DERs by solving the optimal DER coordination problem (ODCP), which is cast as a static optimization problem. We develop efficient estimation algorithms that utilize measurements to estimate the parameters in the IO model. Special emphasis is devoted to algorithms that address the potential collinearity issue in the measurements, and formulations that significantly reduce the number of parameters to be estimated. The idea of data-driven coordination is also applied to address the problem of coordinating load tap changers (LTCs)---an important class of assets used for voltage control in distribution networks---using only measurements of voltage magnitudes. Different from the ODCP that is cast as a static optimization problem, the optimal LTC coordination problem is cast as a multi-stage decision-making problem and formulated as a Markov decision process (MDP), in which the unknown power injections are modeled as uncertainty sources. The MDP is solved via a reinforcement learning algorithm to obtain a control policy that maps the voltage magnitude measurements to the optimal tap positions. The data-driven nature makes the proposed frameworks intrinsically adaptive and robust to changes in operating conditions and power distribution system models, which are illustrated via extensive case studies

Watchers, Watched, and Watching in the Digital Age: Reconceptualization of it Monitoring as Complex Action Nets

Despite increasing studies of information technology (IT) monitoring, our understanding of how IT-mediates relations between the watcher and watched remains limited in two areas. First, either traditional actor-centric frameworks assuming predefined watcher-watched relationships (e.g., panopticon or synopticon) are adopted or monitoring actors are removed to focus on data flows (e.g., dataveillance, assemblages, panspectron). Second, IT monitoring research predominantly assumes IT artifacts to be stable, bounded, designed objects, with prescribed uses which provides an oversimplified view of actor relationships. To redress these limitations, a conceptual framework of veillance applicable to a variety of possible IT or non-IT-mediated relationships between watcher and watched is developed. Using the framework, we conduct a conceptual review of the literature, identifying IT-enabled monitoring and transformations of actors, goals, mechanisms and foci and develop an action net model of IT veillance where IT artifacts are theorized as equivocal, distributable and open for diverse use, open to edits and contributions by unbounded sets of heterogenous actors characterized by diverse goals and capabilities. The action net of IT veillance is defined as a flexible decentralized interconnected web shaped by multidirectional watcher-watched relationships, enabling multiple dynamic goals and foci. Cumulative contributions by heterogenous participants organize and manipulate the net, having an impact through influencing dispositions, visibilities and the inclusion/exclusion of self and others. The model makes three important theoretical contributions to our understanding of IT monitoring of watchers and watched and their relationships. We discuss implications and avenues for future studies on IT veillance

Advanced analysis of load management and environment friendly energy technologies integration in electric power system

The Commonwealth Scholarship Commission (CSC) in the United Kingdom places its primary emphasis on six distinct development-related themes namely, science and technology for development, strengthening health systems, promoting global prosperity, strengthening resilience and response to crises, access, inclusion, and opportunity, and strengthening global peace, security, and governance. My motivation as a Commonwealth scholar, comes from the discussion surrounding the application of science and technology for the development, which is related to the seventh among 17 sustainable development goals (SDGs). The endorsed goal aims at ensuring that all people have access to energy that is both clean and affordable. In this context, my research focuses on the advanced analysis of load management and energy conservation strategies in developing countries, with Rwanda as its primary focus. Firstly, this research work supports the development of Rwanda's energy system and addresses gaps in the existing energy data by proposing a set of Future Energy Scenarios (FES). The developed FES are used to estimate the energy consumption and generation capacity until 2050. Secondly, this research analyses the impact of technologies that are adopted in the developed FES on the Rwanda’s power system. As Electric Vehicles (EVs) are highlighted as an important component in decarbonisation of transport, the study analyses the EVs deployment into the country’s transport and electricity networks. Another challenge that this research is addressing, is the impact the proposed FESs imposes on the power system inertia constant as a result of the integration of renewable energy sources. This is because conventional power plants are replaced by renewable generation (e.g., photovoltaics considered in this study) that contribute to the reduction of power system inertia. In addition to the feasibility study for the deployment of EVs in the country’s transport and electricity networks, this research also developed a methodology to estimates the inertia constant for three different periods in future, namely, 2025, 2035 and 2050 based on the produced FESs for Rwandan’s power system. Furthermore, the research evaluates the frequency response dynamics for each scenario. Results show that the highest progression in renewable energy sources penetration results in a larger reduction in the system inertia constant. The largest frequency drop was observed during the high progression scenario in the year 2050 where the PV generation and imported power from neighbouring countries through interconnectors is expected to reach more than 30% of the total installed capacity. Finally, to mitigate this large drop in frequency, the work proposed a method for stabilising grid frequency by considering demand flexibility. With the help of the load aggregator, prosumers receive price incentive signals based on their energy consumption and prepare them for their participation in grid frequency stabilisation. By considering the operation of a wide range of renewable energy sources and load management system, the study investigates the reduction of the total reliance on electricity from the grid, in day-ahead and real-time energy markets, while also balancing an anticipated load. The proposed control framework considers the estimated power availability and it is used in conjunction with the participation of a load aggregator for contributing to the stabilisation of grid frequency

Untersuchungen zum Einfluss von Elektrodenkennwerten auf die Performance kommerzieller graphitischer Anoden in Lithium-Ionen-Batterien

Die vorliegende Arbeit liefert einen Beitrag zum Verständnis der elektrochemischen Prozesse an der Elektrodengrenzfläche und im Festkörper graphitischer Anoden für Lithium-Ionen-Batterien. Der Zusammenhang zwischen den intrinsischen Eigenschaften des Aktivmaterials und den resultierenden Eigenschaften von Kompositelektroden stand dabei im Fokus der Untersuchungen. Die Temperaturabhängigkeit von Materialeigenschaften (Diffusionskoeffizient, Austauschstromdichte) und Elektrodeneigenschaften (Verhalten unter Strombelastung) wurde in einem Bereich von 40 °C bis -10 °C erfasst. Dazu werden elektrochemische Charakterisierungsmethoden aus der Literatur vorgestellt und hinsichtlich ihrer Gültigkeit für die Anwendung an realen Elektroden evaluiert. Die elektrochemisch aktive Oberfläche wurde bestimmt und stellte sich als ausschlaggebender Parameter für die Bewertung der Elektrodenprozesse heraus. Auf Basis korrigierter Elektrodenoberflächen konnten Austauschstromdichten für die konkurrierenden Prozesse Lithium-Interkalation und -Abscheidung ermittelt werden. Zusammen mit Kennwerten zur Keimbildungsüberspannung für Lithium-Abscheidung flossen die ermittelten Kennwerte in eine theoretische Berechnung des Zellstroms ein. Es konnte gezeigt werden, dass die Lithium-Abscheidung kinetisch deutlich gegenüber der Lithium-Interkalation bevorzugt ist, nicht nur bei niedriger Temperatur. Die Übertragbarkeit wissenschaftlicher Grundlagenexperimente auf kommerzielle Systeme war bei allen Versuchen Gegenstand der Untersuchungen. In einem separaten Beispiel einer Oberflächenmodifikation mit Zinn wurde diese Problematik besonders verdeutlicht. Zusätzlich wurde die parasitäre Abscheidung von Lithium auf graphitischen Anoden hinsichtlich der Nachweisbarkeit und Quantifizierung evaluiert. Hierfür wurde eine neue Untersuchungsmethode im Bereich der Lithium-Ionen-Batterie zur besseren Detektion von Lithium-Abscheidung und Grenzflächen-Morphologie mittels Elektronenmikroskopie entwickelt. Die Osmiumtetroxid (OsO4) Färbung ermöglichte eine deutliche Verbesserung des Materialkontrasts und erlaubte somit eine gezielte Untersuchung von graphitischen Anoden nach erfolgter Lithium-Abscheidung. Darüber hinaus konnte die selektive Reaktion des OsO4 für eine genauere Betrachtung der Solid Electrolyte Interphase genutzt werden. Eine Stabilisierung der Proben an Luft und im Elektronenstrahl konnte erreicht werden.This work sheds light on the electrochemical processes occurring at commercially processed graphitic anodes. It raises the question whether values published in literature for mostly ideal electrode systems can be readily taken for simulation and design of real electrodes in high-energy cells. A multiple step approach is given, evaluating different methods to determine electrode and material properties independently. The electrochemically active surface area was shown to be a crucial parameter for the calculation of electrode kinetics. Using exchange current densities corrected for the electrode surface area, the overall charging current in a cell could be calculated. The resulting part of lithium deposition in the charging process is strikingly high, not only at low temperatures. To further investigate lithium deposition in terms of morphology and quantity, a method was developed for graphitic anodes. Osmium tetroxide (OsO4) staining serves well as a tool to strongly increase material contrast in electron microscopy. Thus lithium dendrites could be made visible in an unprecedented manner. Furthermore, the selective chemical reaction of osmium tetroxide allows for a better investigation of the multi-layer solid electrolyte interphase as was shown in transmission electron microscopy. Using the staining method, a stabilization of the sample under air and in the electron beam could be achieved

Beamed-Energy Propulsion (BEP) Study

The scope of this study was to (1) review and analyze the state-of-art in beamed-energy propulsion (BEP) by identifying potential game-changing applications, (2) formulate a roadmap of technology development, and (3) identify key near-term technology demonstrations to rapidly advance elements of BEP technology to Technology Readiness Level (TRL) 6. The two major areas of interest were launching payloads and space propulsion. More generally, the study was requested and structured to address basic mission feasibility. The attraction of beamed-energy propulsion (BEP) is the potential for high specific impulse while removing the power-generation mass. The rapid advancements in high-energy beamed-power systems and optics over the past 20 years warranted a fresh look at the technology. For launching payloads, the study concluded that using BEP to propel vehicles into space is technically feasible if a commitment to develop new technologies and large investments can be made over long periods of time. From a commercial competitive standpoint, if an advantage of beamed energy for Earth-to-orbit (ETO) is to be found, it will rest with smaller, frequently launched payloads. For space propulsion, the study concluded that using beamed energy to propel vehicles from low Earth orbit to geosynchronous Earth orbit (LEO-GEO) and into deep space is definitely feasible and showed distinct advantages and greater potential over current propulsion technologies. However, this conclusion also assumes that upfront infrastructure investments and commitments to critical technologies will be made over long periods of time. The chief issue, similar to that for payloads, is high infrastructure costs