Revisiting On-Line Discussion as Practice for Reflective Thinking in Three Sequential Classes

In a previous study, the authors questioned the potential of an on-line environment for increasing productive reflection in three sequential education classes. Of their findings, the issue of consistency stood out as particularly perplexing, namely, why did students exhibit high level reflections sometimes, but not all the time, in an on-line environment? In this follow-up study, the authors question whether in-class reflections coupled with on-line prompts could yield consistently high level pre-service teacher reflections, as measured by individual and class progress over time. This study also examines perceived relationships between the length of a student\u27s reflection and its productivity, as well as a student\u27s depth of focus and productivity. Using the same scoring approach as our previous study, our discussion of the results examines the usefulness of on-line environments for promoting consistently high level pre-service teacher reflection

Using Technology to Develop Preservice Teachers\u27 Reflective Thinking

Developing high-level reflection skills proves troublesome for some preservice teachers. To examine the potential of an online environment for increasing productive reflection, students in three sequential undergraduate education classes responded to regular online prompts. We coded student comments for productive and unproductive reflection, knowledge integration, and analysis of the four aspects of teaching (learners and learning, subject matter knowledge, assessment and instruction ) as described by Davis, Bain, & Harrington (2001). We adapted a scoring approach recommended by Davis & Linn, (2000); Davis (2003) to analyze what aspects of teaching preservice teachers included, emphasized, and integrated when they reflected on their own beliefs about teaching. Discussion examines the utility of online environments for producing productive preservice teacher reflection

CNC Application and Design

Machining is an important manufacturing process that is used in wide range of applications. We acquired primary machine shop skills that provide us an opportunity to mill and drill a class of components to specified dimensions and tolerances. For each component, we created a detailed engineering working drawing that helps to shape and construct all the operations and procedures that must be undertaken, and controlled, to attain component machining without any breakdown or failure. Through hands-on machining, we discovered many different factors involved in milling, drilling, and the effects they exhibit on the tolerance and surface finish of a part

Stirring up trouble: Multi-scale mixing measures for steady scalar sources

The mixing efficiency of a flow advecting a passive scalar sustained by steady sources and sinks is naturally defined in terms of the suppression of bulk scalar variance in the presence of stirring, relative to the variance in the absence of stirring. These variances can be weighted at various spatial scales, leading to a family of multi-scale mixing measures and efficiencies. We derive a priori estimates on these efficiencies from the advection--diffusion partial differential equation, focusing on a broad class of statistically homogeneous and isotropic incompressible flows. The analysis produces bounds on the mixing efficiencies in terms of the Peclet number, a measure the strength of the stirring relative to molecular diffusion. We show by example that the estimates are sharp for particular source, sink and flow combinations. In general the high-Peclet number behavior of the bounds (scaling exponents as well as prefactors) depends on the structure and smoothness properties of, and length scales in, the scalar source and sink distribution. The fundamental model of the stirring of a monochromatic source/sink combination by the random sine flow is investigated in detail via direct numerical simulation and analysis. The large-scale mixing efficiency follows the upper bound scaling (within a logarithm) at high Peclet number but the intermediate and small-scale efficiencies are qualitatively less than optimal. The Peclet number scaling exponents of the efficiencies observed in the simulations are deduced theoretically from the asymptotic solution of an internal layer problem arising in a quasi-static model.Comment: 37 pages, 7 figures. Latex with RevTeX4. Corrigendum to published version added as appendix

An Extensive Evaluation of the Internet's Open Proxies

Open proxies forward traffic on behalf of any Internet user. Listed on open proxy aggregator sites, they are often used to bypass geographic region restrictions or circumvent censorship. Open proxies sometimes also provide a weak form of anonymity by concealing the requestor's IP address. To better understand their behavior and performance, we conducted a comprehensive study of open proxies, encompassing more than 107,000 listed open proxies and 13M proxy requests over a 50 day period. While previous studies have focused on malicious open proxies' manipulation of HTML content to insert/modify ads, we provide a more broad study that examines the availability, success rates, diversity, and also (mis)behavior of proxies. Our results show that listed open proxies suffer poor availability--more than 92% of open proxies that appear on aggregator sites are unresponsive to proxy requests. Much more troubling, we find numerous examples of malicious open proxies in which HTML content is manipulated to mine cryptocurrency (that is, cryptojacking). We additionally detect TLS man-in-the-middle (MitM) attacks, and discover numerous instances in which binaries fetched through proxies were modified to include remote access trojans and other forms of malware. As a point of comparison, we conduct and discuss a similar measurement study of the behavior of Tor exit relays. We find no instances in which Tor relays performed TLS MitM or manipulated content, suggesting that Tor offers a far more reliable and safe form of proxied communication

The Physics of the B Factories

This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

Arts Integration in Teacher Preparation: Teaching the Teachers

This classroom study focused on modeling a hands-on approach for understanding classroom applications of multiple intelligence theory through arts-based integration. Thirty-five preservice teachers enrolled in Educational Psychology classes participated in an interdisciplinary geometry lesson modeling Artful Learning™, experiencing an arts- based pedagogical approach in the lesson. Students identified and described geometric concepts and relationships and photographed geometrical elements authentically on campus as part of the model’s original creation. Assessment of lesson objectives revealed that students appreciated arts-based pedagogy, but had difficulty translating theory into practice when creating their original lesson plans. Discussion includes reflective responses of preservice teachers to inquiry and arts-based classroom instruction for enhancing student understanding, as well as implications for integrating art pedagogy in professional practices

NACA Technical Notes

Report presenting an experimental investigation to determine the effects of various geometric and flow factors on the discharge coefficients for circular holes with flow parallel to the plane of the hole. The geometric and flow factors considered were hole diameter, wall thickness at the hole, parallel-flow duct height, boundary-layer thickness, parallel-flow velocity, static-pressure level, and pressure ratio across the test hole