DRUM - Digital Repository at the University of Maryland

DRUM collects, preserves, and provides public access to the scholarly output of the university. Faculty and researchers can upload research products for rapid dissemination, global visibility and impact, and long-term preservation.

Submit to DRUM

Submit to DRUM

To submit an item to DRUM, login using your UMD credentials. Then select the "Submit Item to DRUM" link in the navigation bar. View DRUM policies and submission guidelines.
Equitable Access Policy

Equitable Access Policy

The University of Maryland Equitable Access Policy provides equitable, open access to the University's research and scholarship. Faculty can learn more about what is covered by the policy and how to deposit on the policy website.
Theses and Dissertations

Theses and Dissertations

DRUM includes all UMD theses and dissertations from 2003 forward.

List of Communities

Collections Organized by Department

UM Community-managed Collections

Recent Submissions

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    Cyber-Physical Rigid Inverted Flag Experimental Dataset
    (2026) Townsend, Winthrop; Huertas-Cerdeira, Cecilia
    This dataset contains experimental measurements from a cyber-physical rigid inverted flag aeroelastic system. The experimental configuration consists of a finite-aspect-ratio plate oriented in a wind tunnel at Reynolds numbers on the order of 10^5 with a free leading edge and a torsionally mounted trailing edge. The system exhibits a range of complex aeroelastic phenomena, including large-amplitude limit-cycle oscillations that arise from coupling between the flag structure and its vortex-dominated wake. Measurements include time-history rotational kinematics, with angular position and velocity obtained from both an onboard rotational encoder and an image-based flag tracking algorithm. Experimental access to the structure's stiffness and damping characteristics allows for the generation of a diverse dataset that spans a broad parametric space. The database includes more than 1,100 response records, representing over 2 hours and 50 minutes of flow-excited data. The response records include steady-state response trajectories as well as transient response data acquired following a controlled perturbation of the excited system. The repository is intended to serve as a comprehensive resource for data-driven modeling, system identification, optimization, and reduced-order modeling of complex aeroelastic systems.
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    Applying the SARAH Model to Library Change Management
    (ASEE, 2026) Kern, Sara; Barbrow, Sarah; Jane Dooley, Sarah; Lester, Sarah E.; Over, Sarah; Weiss, Sarah
    Academic libraries are the heart of colleges and universities and, as such, are often centrally involved in and impacted by changes in the greater higher education landscape. For those working in these spaces, familiarity with strategies for managing change is essential to support yourself and others during especially turbulent times. The SARAH model, described below in bullet points with our modifications in brackets, offers a memorable way to understand responses to change, be they our own or others. S - Shock or Surprise A – Anger [Anxiety, Alert, or Anticipation] R – Resistance or Rejection [Re-engagement, or Rationalization] A - Acceptance H - Help or Hope This is not an inevitable cycle and some people may not move through the stages in a linear manner. The existing model offers structure, but our addition adds flexibility, opportunities for positive reactions, and library-specific examples and context. This model, and our modifications to it, helps individuals identify their own or others reaction to change, recognize where they might be in the process, and respond with empathy and support. By understanding feelings and reactions of ourselves and others, we can provide thoughtful and intentional support during difficult times. United by their shared name, the Sara(h)s of ELD bring together their diverse experiences and perspectives to present the SARAH model for use in academic libraries, and particularly for those working with Engineering or STEM departments. This paper and poster will present the SARAH model alongside strategies and examples for supporting both yourself and others when managing change in a library context.
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    NASA GEOS-CCM Meteorological, Flash Rate, and LWI Flag output
    (2026-08) Seiler, Madilynn; Allen, Dale
    NASA GEOS-CCM instantaneous hourly output. Data on a 0.5ºx0.5º resolution. In this dataset, there are 13 meteorological variables used for training the lightning parameterization scheme, SEILER-Net. There is also a Land-Water-Ice flag used for analysis along with the flash rate output from NASA GEOS-CCM that is also used for analysis. Amazon Basin domain (10ºN-22ºS, 35º-67ºW) and USA domain (18º-50ºN, 72º-104ºW) from June 2023-December 2024.
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    Geostationary Lightning Mapper (GLM) Dataset USA and Amazon
    (2026-08) Seiler, Madilynn; Allen, Dale
    GLM hourly flash rates are given for Amazon Basin domain (10ºN-22ºS, 35º-67ºW) and USA domain (18º-50ºN, 72º-104ºW) from June 2023-December 2024. This data is used as a label for training the lightning flash rate parameterization scheme, SEILER-Net.
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    Improving frequency stability using slowly modulated adaptive feedback
    (American Physical Society, 2026-05-19) Dankowicz, Harry; Shaw, Steven W.; Shoshani, Oriel
    We present a new method for improving frequency stability in a self-sustained oscillator using a secondary feedback loop acting outside the main sustaining loop with adaptively-controlled amplitude and phase shift. We show that quite simple adaptive control laws for the control states of the secondary feedback signal can affect the way that noise circulates in the oscillator so as to reduce or even eliminate (in theory) phase diffusion, i.e., the rate of linear growth with time of the variance of the oscillator output phase. Our rigorous treatment of this effect is based on a linearized analysis of the noisy slow-flow amplitude and phase equations for a relevant general class of systems, from which we derive an explicit expression for the corresponding asymptotic rate of phase diffusion. Using this result, we consider different choices for tailoring the actuation from the secondary feedback loop. This includes tuning a phase coupling constant that ensures that the noise driving the output phase also drives one of the adaptive control states, which represents a generalization of a desirable behavior observed in internally resonant coupled mode operation. We show that such feedback design may be used to eliminate effects that commonly arise from the conversion of amplitude fluctuations to phase diffusion, analogous to operation at zero dispersion points, and to improve upon the phase cleaning effect associated with internal resonance to even achieve the ideal situation of zero phase diffusion. We validate our theoretical findings with numerical simulations that agree remarkably well with the theory. The presented results establish a framework for achieving extraordinary frequency stability using slowly varying states of the resonator and feedback.