From an Autonomous to a Collaborative Website Redesign Process: The University of Denver Libraries Experience

Librarians traditionally have insisted on designing and developing the library’s website in-house. An inhouse developed website allows librarians full control of its design, content, and delivery. The library website is also distinguished by its research orientation compared to the university’s marketing-driven purposes. However, in the age of gaining competitive advantage by promoting campus branding, shared services, and collaborative initiatives by various administrative units, libraries could be a stronger partner with other campus departments. This article describes the University of Denver Libraries’ transformation from an autonomous information silo to an integrated Web portal within the University’s Marketing & Communication division. In the course of this change, unlike turning a switch on or off, the librarians experienced stages of uncertainty, denial, negotiation, and acceptance. The project was successfully completed and became an exemplar for many other campus-wide initiatives. By sharing this experience, the authors hope to encourage other libraries to consider the tangible and intangible benefits that university-wide collaborations can elicit

Skin layer recovery of free-surface wakes: Relationship to surface renewal and dependence on heat flux and background turbulence

The thermal signatures of free-surface wakes observed in the open ocean show that the recovery of the cool skin layer is related to the degree of surface mixing and to ambient environmental conditions. Wakes produced by two surface-piercing cables of O(10−2 m) in diameter are analyzed using infrared imagery. Under low-wind-speed conditions when the swell and surface current were aligned, the wakes exhibited distinctive patchlike features of O(1 m) in diameter that were generated by the passage of individual waves. The time t* required by the skin layer to recover from these disturbances is compared to the surface-renewal timescale τ used in heat and gas flux models. At low wind speeds, t* is comparable to τ, but at moderate wind speeds the agreement is poor. The spatial and temporal variations in the skin temperature of these wakes are related to a wave Reynolds number used to characterize the strength of the disturbance due to the waves. The recovery process is characterized in terms of the restoring internal energy flux Jr which is proportional to both the initial thickness and the thermal recovery rate of the skin layer and was found to be directly related to the strength of the surface disruption. Comparison of the wake results with laboratory and other field measurements of breaking waves implies that Jr is also a strong function of the net heat flux and background turbulence, which relate directly to the existing environmental conditions such as wind stress and sea state. Our results demonstrate that Jr may vary by several orders of magnitude, depending on the environmental conditions

Online learning for robust voltage control under uncertain grid topology

Voltage control generally requires accurate information about the grid's topology in order to guarantee network stability. However, accurate topology identification is challenging for existing methods, especially as the grid is subject to increasingly frequent reconfiguration due to the adoption of renewable energy. Further, running existing control mechanisms with incorrect network information may lead to unstable control. In this work, we combine a nested convex body chasing algorithm with a robust predictive controller to achieve provably finite-time convergence to safe voltage limits in the online setting where the network topology is initially unknown. Specifically, the online controller does not know the true network topology and line parameters, but instead learns them over time by narrowing down the set of network topologies and line parameters that are consistent with its observations and adjusting reactive power generation accordingly to keep voltages within desired safety limits. We demonstrate the effectiveness of our approach in a case study on a Southern California Edison 56-bus distribution system. Our experiments show that in practical settings, the controller is indeed able to narrow the set of consistent topologies quickly enough to make control decisions that ensure stability in both linearized and realistic non-linear models of the distribution grid.Comment: under submission. arXiv admin note: substantial text overlap with arXiv:2206.1436