With the rapid growth of computer science in K-12 education has come a significant increase in the need for computer science teachers. This demand has meant that a large number of K-12 educators are being asked to teach computer science with very little formal preparation in the subject. For many, this creates a unique experience in which they are often learning the content for the first time while simultaneously preparing to teach or actively teaching in their own classrooms. Although this can be a challenging situation, the circumstances present a somewhat rare situation in which educators can meaningfully reflect on the intersection between teaching and learning by examining their experiences and lessons learned as they participate in both worlds simultaneously. With this poster, we discuss some of the more common observations about learning programming from an analysis of responses from over 220 participants in a state-wide CS teacher preparation program. These observations may be broadly valuable for educators teaching programming courses.

Training teachers to teach high-quality computer science courses is an important step towards increasing participation in computer science. To meet this need, our Research Practitioner Partnership (RPP) was formed with the primary goal of creating a comprehensive, graduate-level program to train in-service CS teachers with little to no prior CS coursework. Since its formation, the RPP has iteratively designed, implemented, and evaluated a five-course program to improve participants' knowledge of computer science content and pedagogy while allowing them to earn the state's grades 5-12 computer science endorsement. Our program has successfully scaled from a single-site pilot to a truly statewide, multi-site program, emphasizing educator-based, standards-based, and cohort-based instruction. Currently, the RPP serves 250 in-service participants.

The work described in this poster builds on previous work funded by the NSF through a CSForAll:RPP grant (NSF 17-525, small-scale, Award #1738784). In our original work we developed and piloted a professional development (PD) sequence which allows in-service high school teachers to teach high quality computer science courses and earn the state's then newly created computer science endorsement.

The COVID-19 pandemic has presented unprecedented challenges across the world and universities are not saved either. Standard classroom activities in COVID era are even more challenging, with the primary challenge being ensuring physical distancing. We present a smart classroom system, BubbleNet, that attempts to relax these challenges. BubbleNet leverages cost-effective (~ $30) IoT nodes with motion sensors. The IoT nodes collaborate with each other via OpenThread - the latest open-source mesh networking protocol released by Google. In this paper, we present the development and demonstration of Bub-bieN et for monitoring physical distancing rules in a classroom.

The file system is a critical and ubiquitous part of our operating systems, yet it is often poorly understood. While many undergraduate students studying computer science learn the fundamentals of operating systems, they can often find it difficult to fully comprehend how a file system works. This difficulty may be in part because the true workings of a file system are hidden from the user, and so any coverage of its operation was done, by necessity, in the abstract. To address this, we have created a tool which visualizes the operations of the file system in situ, much like Wireshark provides information on what is happening on a network. Our tool, named Fileshark, provides an easy-to-use interface for visualizing the processes involved in reading, storing, and deleting data. Our tool can aid in the teaching of operating systems, computer forensics, and common concepts like transactions that are also found in other domains (e.g. databases and distributed systems).

Ubiquitous touch projection technology is entering the market and allows touch screens to be projected onto any smooth surface at a lower cost. We created a mathematics manipulative application for a low-cost, ubiquitous touch projection system, and we conducted an observational study with 18 third-grade elementary students. Through our analysis of both video and system data, we identify common student interaction problems, evaluate how those interaction problems affect usability, engagement, and pair-work, and we make practical suggestions to aid future developers, educators, and students in using such a platform.

One important aspect of privacy is the ability to securely delete sensitive data from electronic storage in such a way that it cannot be recovered; we call this action secure deletion . Short of physically destroying the entire storage medium, existing software secure-deletion solutions tend to be piecemeal at best -- they may only work for one type of storage or file system, may force the user to delete all files instead of selected ones, may require the added complexities of encryption and key storage, may require extensive changes and additions to the computer's operating system or storage firmware, and may not handle system crashes gracefully. We present TrueErase, a holistic secure-deletion framework for individual systems that contain sensitive data. Through design, implementation, verification, and evaluation on both a hard drive and NAND flash, TrueErase shows that it is possible to construct a per-file, secure-deletion framework that can accommodate different storage media and legacy file systems, require limited changes to legacy systems, and handle common crash scenarios. TrueErase can serve as a building block by cryptographic systems that securely delete information by erasing encryption keys. The overhead is dependent on spatial locality, number of sensitive files, and workload (computational- or I/O-bound).

The ability to securely delete sensitive data from electronic storage is becoming important. However, current per-file deletion solutions tend to be limited to a segment of the operating system's storage data path or specific to particular file systems or storage media.