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  1. Security is a well-known function to any transmission operator and system planner. As the world is moving toward the decarbonization of the power industry, it is more complicated for the system operators to maintain an acceptable level of security in the power system operation. More large-scale wind farms are being incorporated into the grid, and thus, the voltage stability concern is increasing. In practice, several contingencies are imagined by the system operators to assess the reliability of the grid. Since voltage stability is one of the major menaces that can trigger voltage instability in a power system, this paper ismore »attempting to present to the transmission system planners and operators a dedicated methodology to facilitate the incorporation of large-scale wind farms into a transmission grid under high penetration of wind power. the stability of a wind-dominated power system is discussed based on Q-V and P-V methodologies and some N-1 contingencies with the Remedial Action Schemes (RAS). Furthermore, a methodology to rank the worst contingencies and to predict the voltage collapse during the highest wind penetration level is presented. Simulations have been, extensively, carried out to examine the methodology and have provided valuable information about the static security of the wind-dominated power system. The results can be used by the transmission system operator to anticipate voltage instability or voltage collapse in the power system during high wind penetration levels.« less
    Free, publicly-accessible full text available November 23, 2022
  2. Dipeptides, which consist of two amino acids joined by a peptide bond, have been shown to have catalytic functions. This observation leads to fundamental questions relevant to the origin of life. How could peptides have become colocalized with the first protocells? Which structural features would have determined the association of amino acids and peptides with membranes? Could the association of dipeptides with protocell membranes have driven molecular evolution, favoring dipeptides over individual amino acids? Using pulsed-field gradient nuclear magnetic resonance, we find that several prebiotic amino acids and dipeptides bind to prebiotic membranes. For amino acids, the side chains andmore »carboxylate contribute to the interaction. For dipeptides, the extent of binding is generally less than that of the constituent amino acids, implying that other mechanisms would be necessary to drive molecular evolution. Nevertheless, our results are consistent with a scheme in which the building blocks of the biological polymers colocalized with protocells prior to the emergence of RNA and proteins.« less
    Free, publicly-accessible full text available July 20, 2022
  3. The increasing capacity from inverter-based resources (IBR) creates challenges for designing and operating electric power systems. In particular, wind and solar generation has very different characteristics compared to conventional turbo generators. This research investigates the critical clearing times for IBR as larger amounts of wind generation brought online. This paper develops a new six-bus transmission test systems for which multiple wind stations are interconnected. An exhaustive study of fault locations with respect to load levels and line impedances for a wide range of IBR penetration levels was performed with respect to inverter stability analysis to determine the corresponding critical clearingmore »times. The results show that voltage stability at IBR points of interconnection can occur at not only higher penetration levels, but at lower penetrations as well.« less
  4. The role of modern engineers as problem-definer often require collaborating with cross-disciplinary teams of professionals to understand and effectively integrate the role of other disciplines and accelerate innovation. To prepare future engineers for this emerging role, undergraduate engineering students should engage in collaborative and interdisciplinary activities with faculties and students from various disciplines (e.g., engineering and social science). Such cross-disciplinary experiences of undergraduate engineering students are not common in today’s university curriculum. Through a project funded by the division of Engineering Education and Centers (EEC) of the National Science Foundation (NSF), a research team of the West Virginia University developedmore »and offered a Holistic Engineering Project Experience (HEPE) to the engineering students. Holistic engineering is an approach catering to the overall engineering profession, instead of focusing on any distinctive engineering discipline such as electrical, civil, chemical, or mechanical engineering. Holistic Engineering is based upon the fact that the traditional engineering courses do not offer sufficient non-technical skills to the engineering students to work effectively in cross-disciplinary social problems (e.g., development of transportation systems and services). The Holistic Engineering approach enables engineering students to learn non-engineering skills (e.g., strategic communication skills) beyond engineering math and sciences, which play a critical role in solving complex 21st-century engineering problems. The research team offered the HEPE course in Spring 2020 semester, where engineering students collaborated with social science students (i.e., students from economics and strategic communication disciplines) to solve a contemporary, complex, open-ended transportation engineering problem with social consequences. Social science students also received the opportunity to develop a better understanding of technical aspects in science and engineering. The open ended problem presented to the students was to “Restore and Improve Urban Infrastructure” in connection to the future deployment of connected and autonomous vehicles, which is identified as a grand challenge by the National Academy of Engineers (NAE) [1].« less
    Free, publicly-accessible full text available July 1, 2022
  5. In this paper, we show that under over-parametrization several standard stochastic optimization algorithms escape saddle-points and converge to local-minimizers much faster. One of the fundamental aspects of over-parametrized models is that they are capable of interpolating the training data. We show that, under interpolation-like assumptions satisfied by the stochastic gradients in an overparametrization setting, the first-order oracle complexity of Perturbed Stochastic Gradient Descent (PSGD) algorithm to reach an \epsilon-local-minimizer, matches the corresponding deterministic rate of ˜O(1/\epsilon^2). We next analyze Stochastic Cubic-Regularized Newton (SCRN) algorithm under interpolation-like conditions, and show that the oracle complexity to reach an \epsilon-local-minimizer under interpolation-like conditions,more »is ˜O(1/\epsilon^2.5). While this obtained complexity is better than the corresponding complexity of either PSGD, or SCRN without interpolation-like assumptions, it does not match the rate of ˜O(1/\epsilon^1.5) corresponding to deterministic Cubic-Regularized Newton method. It seems further Hessian-based interpolation-like assumptions are necessary to bridge this gap. We also discuss the corresponding improved complexities in the zeroth-order settings.« less
  6. Abstract The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hardmore »scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.« less
    Free, publicly-accessible full text available December 1, 2023
  7. Although engineering graduates are well prepared in the technical aspects of engineering, it is widely acknowledged that there is a need for a greater understanding of the socio-economic contexts in which they will practice their profession. The National Academy of Engineering (NAE) reinforces the critical role that engineers should play in addressing both problems and opportunities that are technical, social, economic, and political in nature in solving the grand challenges. This paper provides an overview of a nascent effort to address this educational need. Through a National Science Foundation (NSF) funded program, a team of researchers at West Virginia Universitymore »has launched a Holistic Engineering Project Experience (HEPE). This undergraduate course provides the opportunity for engineering students to work with social science students from the fields of economics and strategic communication on complex and open-ended transportation engineering problems. This course involves cross-disciplinary teams working under diverse constraints of real-world social considerations, such as economic impacts, public policy concerns, and public perception and outreach factors, considering the future autonomous transportation systems. The goal of the HEPE platform is for engineering students to have an opportunity to build non-technical—but highly in-demand—professional skills that promote collaboration with others involved in the socio-economic context of engineering matters. Conversely, the HEPE approach provides an opportunity for non-engineering students to become exposed to key concepts and practices in engineering. This paper outlines the initial implementation of the HEPE program, by placing the effort in context of broader trends in education, by outlining the overall purposes of the program, discussing the course design and structure, reviewing the learning experience and outcomes assessment process, and providing preliminary results of a baseline survey that gauges students interests and attitudes towards collaborative and interdisciplinary learning.« less