Effective ANN Topologies for Use as Genotypes for Evaluating Design and Fabrication

There is promise in the field of Evolutionary Design for systems that evolve not only what to manufacture but also how to manufacture it. EvoFab is a system that uses Genetic Algorithms to evolve Artificial Neural Networks (ANNs) which control a modified 3d-printer with the goal of automating some level of invention. ANNs are an obvious choice for use with a system like this as they are canonically evolvable encodings, and have been successfully used as evolved control systems in Evolutionary Robotics. However, there is little known about how the structural characteristics of an ANN affect the shapes that can be produced when that ANN controls a system like a 3d-printer. We consider the relationship between certain structural characteristics of an ANN and the ability of that ANN to produce complex geometric shapes by controlling a 3d-printer. We develop an understanding of shape complexity for 2d shapes in a simulated 3d-printer in order to use Genetic Algorithms to optimize ANNs with fixed structures to produce complex outputs and assess the relationship between topologies of ANNs and the systems success in producing complex outputs under evolutionary optimization

Investigating Habituation to Premonitory Urges in Behavior Therapy for Tic Disorders

Behavior therapy is effective for Persistent Tic Disorders (PTDs), but behavioral processes facilitating tic reduction are not well understood. One process, habituation, is thought to create tic reduction through decreases in premonitory urge severity. The current study tested whether premonitory urges decreased in youth with PTDs (N = 126) and adults with PTDs (N = 122) who participated in parallel randomized clinical trials comparing behavior therapy to psychoeducation and supportive therapy (PST). Trends in premonitory urges, tic severity, and treatment outcome were analyzed according to the predictions of a habituation model, whereby urge severity would be expected to decrease in those who responded to behavior therapy. Although adults who responded to behavior therapy showed a significant trend of declining premonitory urge severity across treatment, results failed to demonstrate that behavior therapy specifically caused changes in premonitory urge severity. In addition, reductions in premonitory urge severity in those who responded to behavior therapy were significant greater than those who did not respond to behavior therapy but no different than those who responded or did not respond to PST. Children with PTDs failed to show any significant changes in premonitory urges. Reductions in premonitory urge severity did not mediate the relationship between treatment and outcome in either adults or children. These results cast doubt on the notion that habituation is the therapeutic process underlying the effectiveness of behavior therapy, which has immediate implications for the psychoeducation and therapeutic rationale presented in clinical practice. Moreover, there may be important developmental changes in premonitory urges in PTDs, and alternative models of therapeutic change warrant investigation

PhoSim-NIRCam: Photon-by-photon image simulations of the James Webb Space Telescope's Near-Infrared Camera

Recent instrumentation projects have allocated resources to develop codes for simulating astronomical images. Novel physics-based models are essential for understanding telescope, instrument, and environmental systematics in observations. A deep understanding of these systematics is especially important in the context of weak gravitational lensing, galaxy morphology, and other sensitive measurements. In this work, we present an adaptation of a physics-based ab initio image simulator: The Photon Simulator (PhoSim). We modify PhoSim for use with the Near-Infrared Camera (NIRCam) -- the primary imaging instrument aboard the James Webb Space Telescope (JWST). This photon Monte Carlo code replicates the observational catalog, telescope and camera optics, detector physics, and readout modes/electronics. Importantly, PhoSim-NIRCam simulates both geometric aberration and diffraction across the field of view. Full field- and wavelength-dependent point spread functions are presented. Simulated images of an extragalactic field are presented. Extensive validation is planned during in-orbit commissioning

Undergraduate Experiential Learning Activity to Improve Communication Skills and Engage Public School Students in Forest Ecological Principles

Since 1988, Virginia Tech has had various programs in which undergraduate students visited public schools and presented natural resources-based information One of the more popular presentations involved teaching public school students how to identify and measure forest vegetation. In 2008, the Ambassadors for Conservation Education (ACE) Program was developed to enlist a larger, more diverse student body to participate in forestry and agriculturally-related undergraduate degree programs. In this program, undergraduates visited two parks and six high schools with forest nearby to collect forest ecological data with high school students. At each park and school we established a series of 0.02-ha permanent plots. Accurate baseline data on tree species, and tree diameter (\u3e10 cm) were collected on all plots by Virginia Tech faculty and staff. These data, along with the exercise objectives and field trip preparation material (e.g., data sheets), were placed on the internet for use by teachers. To prepare for their teaching days, undergraduate students enrolled in a communication class where they were taught principles of effective communication. The class emphasized outdoor environmental teaching with numerous practice sessions where students improved their skills at teaching outdoors in informal settings. Undergraduates then led high school field trips where students and their teachers visited the plots and collected the same information in the pre-established plots. High schoolers learned principle of tree identification and use of diameter tapes and increment borers. Following data collection, students returned to the classroom and submitted their data via the internet. Relatively accurate data can be collected when trained undergraduates assist high school students closely. Utilizing schools with forest plots nearby greatly increased the number of students reached and eliminates the need for special field trip permission and transportation costs