Fearless Friday: Raegan Gawronski

This week, we are honoring Raegan Gawronski ’19. Raegan is a Women and Gender Sexuality Studies and Philosophy double major from Philadelphia, Pennsylvania. On campus, she works as a senior intern for the Office of Multicultural Engagement, and is currently in the process of starting a First-Generation Student Organization on campus. [excerpt

Sequential design of a linear quadratic controller for the Deep Space Network antennas

A new linear quadratic controller design procedure is proposed for the NASA/JPL Deep Space Network antennas. The antenna model is divided into a tracking subsystem and a flexible subsystem. Controllers for the flexible and tracking parts are designed separately by adjusting the performance index weights. Ad hoc weights are chosen for the tracking part of the controller and the weights of the flexible part are adjusted. Next, the gains of the tracking part are determined, followed by the flexible controller final tune-up. In addition, the controller for the flexible part is designed separately for each mode; thus the design procedure consists of weight adjustment for small-size subsystems. Since the controller gains are obtained by adjusting the performance index weights, determination of the weight effect on system performance is a crucial task. A method of determining this effect that allows an on-line improvement of the tracking performance is presented in this article. The procedure is illustrated with the control system design for the Deep Space Station (DSS)-13 antenna

Predictive control and estimation algorithms for the NASA/JPL 70-meter antennas

A modified output prediction procedure and a new controller design is presented based on the predictive control law. Also, a new predictive estimator is developed to complement the controller and to enhance system performance. The predictive controller is designed and applied to the tracking control of the Deep Space Network 70 m antennas. Simulation results show significant improvement in tracking performance over the linear quadratic controller and estimator presently in use

Design of the reduced LQG compensator for the DSS-13 antenna

A linear-quadratic-Gaussian (LQG) compensator design procedure is proposed for the DSS-13 antenna. The procedure is based on two properties. It is shown that tracking and flexible motion of the antenna are almost independent (the separation property). As a consequence, compensators for the flexible and tracking parts can be designed separately. It is shown also that the balanced LQG compensator's effort is evenly divided between the controller and the estimator. This allows a minimization of the compensator order, which is important for implementation purposes. An efficient compensator reduction procedure that gives a stable low-order compensator of satisfactory performance is introduced. This approach is illustrated with a detailed compensator design for the DSS-13 antenna. The implementation of this compensator design requires an update of the antenna model

The Twenty-Fifth Amendment and the Establishment of Medical Impairment Panels: Are the Two Safely Compatible?

At least two proposals have been offered by prominent members of the medical community to establish “Medical Impairment Panels” to monitor the health of Presidents of the United States and to facilitate the implementation of relevant Sections of the Twenty-Fifth Amendment. The first discussed in this Article was made by Dr. Herbert Abrams, a now deceased professor of radiology at Stanford University; the second by Dr. Bert Park, a prominent Missouri neurosurgeon. Dr. Abrams and Dr. Park spoke and wrote about their plans frequently over the years. The objective of each proposal was to ensure that the Vice President, the Cabinet, and Congress are informed as to situations when a President might be seriously impaired in terms of carrying out his or her official responsibilities as President of the United States. This Article assesses each proposal in turn

Heider Balance in Human Networks

Recently, a continuous dynamics was proposed to simulate dynamics of interpersonal relations in a society represented by a fully connected graph. Final state of such a society was found to be identical with the so-called Heider balance (HB), where the society is divided into two mutually hostile groups. In the continuous model, a polarization of opinions was found in HB. Here we demonstrate that the polarization occurs also in Barabasi-Albert networks, where the Heider balance is not necessarily present. In the second part of this work we demonstrate the results of our formalism, when applied to reference examples: the Southern women and the Zachary club.Comment: 9 pages, 5 figures. Presented on 8th Granada Seminar on Computational and Statistical Physics, Modeling Cooperative Behavior in the Social Sciences, Granada, Spain, 7-11 February 200