In a nationwide initiative to increase computer science Education in K-12, many teachers were recruited to CS teaching positions but without adequate preparation, which can lead to lack of confidence and feelings of isolation [ 35 , 54 ]. In response to these issues, the purpose of this study was to determine the effectiveness of a newly developed summer professional development program with follow-up support with the goal of improving teacher confidence and informing teacher beliefs about computer science. This training featured peer instruction and an emphasis on computer science principles. It took place over three years, and was used to prepare teachers from over 50 schools across a midwestern state. Using Hierarchical Linear Modeling, data analysis from 57 teachers and 871 students showed that teacher confidence and content knowledge increased significantly, and to a greater extent for those who began with the lowest levels of confidence. Students also made significant knowledge gains from before to after taking the class. Student gains were higher for those whose teachers were more confident in their ability to teach computer science.

The field of cybersecurity is becoming very dynamic, and needs continuous evolution. This requires not only the formal and informal education, but a security mindset to be developed for our future workforce. This panel elaborates on some such aspects.

The 2019 Federal Cybersecurity Research and Development Strategic Plan highlighted the mutual needs and benefits of artificial intelligence (AI) and cybersecurity. AI techniques are expected to enhance cybersecurity by assisting human system managers with automated monitoring, analysis, and responses to cybersecurity attacks. Conversely, it is essential to guard AI technologies from unintended uses and hostile exploitation by leveraging cybersecurity practices. Research results at the intersection of AI and cybersecurity can help us to be better equipped with tools and techniques to tackle the growing cybersecurity challenges, while also presenting an opportunity to devise fundamentally new ways to motivate and educate students about cybersecurity in the age of AI. Likewise, a June 2019 technical workshop on 'Artificial Intelligence and Cybersecurity: Opportunities and Challenges' noted how the interplay between AI, machine learning, and cybersecurity will continue to introduce new opportunities and challenges in the security of AI as well as AI for cybersecurity. Basic research at the intersection of AI, cybersecurity, and education has the potential to expand existing AI opportunities and resources in cybersecurity education and workforce development. Education efforts are needed to foster workforce knowledge and skills about applying AI expertise to cybersecurity as well as building robust and trustworthy AI. This BOF session will bring together researchers who are interested in these collaborative explorations.

Most U.S. states support college-readiness and access through dual enrollment, in which high school students enroll in college courses. Concurrent enrollment (CE) allows students to take college courses in their own high school, taught by high school teachers approved by the partner college. CE has positive effects on students' education, but rarely is CS available through CE. Unlike AP, CE provides college credit to students who are assessed throughout the course rather than by a single high-stakes exam/project. This panel will showcase four different types of post-secondary institutions' experiences offering CS-through-CE and discuss its potential as an entry point into CS for students underrepresented in computing, including those in urban and rural settings. Panelists will share challenges (such as teacher credentialing) and benefits of CS-through-CE. The audience will understand supports and barriers to creating CS-through-CE courses, will be provided with resources, and will crowd-source possible next steps in implementing CE as a model for broadening participation.

SIGCSE is packed with teaching insights and inspiration. However, we get these insights and inspiration from hearing our colleagues talk about their teaching. Why not just watch them teach? This session does exactly that. Six exceptional educators will present their favorite piece of innovative lecture content just as they would their students. The moderator, Colleen Lewis, will describe the central pedagogical move within the innovation and how this connects to education research. The goal of the session is to inspire SIGCSE attendees by highlighting innovative instruction by exceptional educators. The specific content of the innovative instruction may be applicable for some attendees, and the discussion of the underlying pedagogical move within each innovation can be applied across the attendees' teaching.

Common barriers to broad-based adoption of Computer Science in secondary schools include 1) insufficient numbers of trained teachers who are capable of teaching CS courses in K-12 schools, and 2) a narrow base of students interested in taking CS courses which does not include a large number of females or students from traditionally underrepresented racial groups. In an effort to overcome these obstacles, we developed and employed a teacher professional development program to develop both content and pedagogical strategies to teach Computer Science Principles while also broadening and expanding participation in CS. Teachers were selected for this program in an effort to understand the impact of the intervention with teachers of diverse backgrounds, who teach in a variety of types of schools and with diverse student populations, and with a range of previous Computer Science content knowledge and teaching experience. Teacher content mastery, confidence and attitudes, as well as student content mastery and confidence were assessed at multiple times. Key goals of the program were to develop ability and confidence in programming skills among teachers and students, and to train and encourage teachers to use peer instruction, allowing for a great deal of interaction among students and engagement with the content facilitating the development of expertise among students. Significant findings showed that teachers improved in both knowledge and confidence after taking the workshop, and the gains were evident for their students as well. Their students also demonstrated improvement in both skills and confidence after taking CS Principles, regardless of gender, race, or ethnicity.

Analytical reasoning is central to code correctness, and every computer science curriculum aims to teach students how to achieve this objective in one form or another. With the acceptance of object-based computing and component-based software engineering, the need for analytical reasoning that is based on formal contracts to establish correctness of software across module boundaries has become ever more obvious. Yet there are few institutions that have integrated modular, analytical reasoning principles into their undergraduate curriculum. Among many reasons for this shortcoming are: the effort it takes overloaded faculty to integrate new ideas of any kind in their courses, the challenge of institutionalizing ideas within a specific context, and constraints of a particular college. This paper presents our experiences over nearly two decades at five different institutions with the hope that they will serve as useful curriculum examples for like-minded educators at other institutions.

No abstract available.

In this paper, we present a security and privacy enhancement (SPE) framework for unmodified mobile operating systems. SPE introduces a new layer between the application and the operating system and does not require a device be jailbroken or utilize a custom operating system. We utilize an existing ontology designed for enforcing security and privacy policies on mobile devices to build a policy that is customizable. Based on this policy, SPE provides enhancements to native controls that currently exist on the platform for privacy and security sensitive components. SPE allows access to these components in a way that allows the framework to ensure the application is truthful in its declared intent and ensure that the user's policy is enforced. In our evaluation we verify the correctness of the framework and the computing impact on the device. Additionally, we discovered security and privacy issues in several open source applications by utilizing the SPE Framework. From our findings, if SPE is adopted by mobile operating systems producers, it would provide consumers and businesses the additional privacy and security controls they demand and allow users to be more aware of security and privacy issues with applications on their devices.

A central goal of computer science education is to teach students how to reason about the correctness of the code they write. Typically, students use a trial and error process and check that their logic "works" by running it on test inputs. Typically, instructors encour-age them towards logical reasoning through manual tracing of the code. Rarely reasoning tools are used in the process, at least partly because few instructors are familiar with them and fewer have the time to investigate and experiment. The purpose of this panel is to introduce the attendees to a variety of reasoning tools the presenters have used in their classrooms. In some cases, the tools have been used in only one or two classes of a course to illustrate specific points. In other cases, entire projects have been done using the tools. The courses range from the introductory sequence and dis-crete structures to software engineering and graduate-level courses. The tools are freely available on the web and attendees will be encouraged to experiment with the reasoning tools on their own laptops to solve simple reasoning problems.

Programming support for multi-threaded applications on embedded microcontroller platforms has attracted a considerable amount of research attention in the recent years. This paper is focused on this problem, and presents UnStacked C, a source-to-source transformation that can translate multithreaded programs written in C into stackless continuations. The transformation can support legacy code by not requiring any changes to application code; only the underlying threading library needs modifications. We describe the details of UnStacked C in the context of the TinyOS operating system for wireless sensor network applications. We present a modified implementation of the TOSThreads library for TinyOS, and show how existing applications programmed using TOSThreads can be automatically transformed to use stackless threads with only modifications in the build process. By eliminating the need to allocate individual thread stacks and by supporting lazy thread preemption, UnStacked C enables a considerable saving of memory used and power consumed, respectively.

Mobile devices have experienced explosive growth and rapid adoption. These devices have also become troves of security and privacy data of the consumers that utilize them. What makes mobile devices unique from traditional computing platforms is the additional sensing components they contain and their ease of access which allow consumers to make these devices a part of their lives. Additionally these devices are fragmented in operating systems, sensing capabilities, and device manufacturers. In this paper we define an ontology that can be utilized as a foundation for enforcing security and privacy policies across all mobile devices, and use the ontology to define policies and to model knowledge elements for mobile devices. We also identify areas where the policies can be applied, including whether to enforce policies on the device or in the cloud.

The need for high-frequency signal acquisition and processing is becoming increasingly prevalent in sensor networks. Applications that require high-frequency data sampling are presently at a disadvantage; applications that only sample at high data rates (and not process any of it locally) end up transmitting large quantities of data, greatly reducing network lifetime. Other applications that do use in-network signal processing rely on power-hungry motes.

Time synchronization is an important service for wireless sensor network applications. Nodes in the network stay synchronized by exchanging periodic messages that carry local timestamps. Several algorithms have been proposed in the literature that are suited to different kinds of application scenarios. A common problem across these time synchronization algorithms is that the energy cost of message exchange is high. In fact, the cost of radio communication far outstrips the cost of performing local operations on the processor. If the message exchanges were stopped, nodes will fall out of sync, and may no longer be able to meet application requirements. In this paper, we present a wrapper-based approach to sustained time synchronization for wireless sensor networks. As such, our solution will act as a wrapper around a given time synchronization protocol, and will apply local corrector operations to extend the time duration between two message exchanges between nodes. Our wrapper performs at least as good as the original protocol provided, reduces the number of message exchanges on average, and consequently the energy consumed, significantly. We present an implementation of our wrapper for TinyOS and evaluate it on XSM motes in conjunction with TPSN, a popular time synchronization protocol for sensor networks.

We present DESALalpha, a realization of the dynamic embedded sensor-actuator language for Telos-based devices. The platform provides native support for: (i) rule-based programming; (ii) synchronized action scheduling; (iii) neighborhood management; and (iv) distributed state sharing. We describe the design and implementation of DESALalpha, present examples that illustrate its use, and summarize the resource requirements of compiled applications. Finally, we present lessons learned based on our use of DESALalphaduring the past year.

Over the last several years, large-scale wireless mote networks have made possible the exploration of a new class of highly-concurrent and highly-distributed applications. As the horizon of what kinds of applications can be built on these networked embedded systems keeps expanding, there is a need to keep the activity of programming such systems easy, efficient, and scalable. We make three major contributions in this paper. First, we present a library for TinyOS and nesC that enables true multi-threading on a mote. This library includes support for all mote platforms in use currently (AVR, MSP). Second, we present a tool that can effectively and accurately compute stack requirements for multithreaded programs. Such analysis ensures that the stacks allocated to individual threads are correctly sized. Finally, we present a collection of programming abstractions that simplifies the construction of concurrent systems for the mote platform. We also present experimental results obtained from several example systems built using our concurrent programming abstractions and the underlying thread library.

No abstract available.

A failure detector is an important building block when constructing fault-tolerant distributed systems. In asynchronous distributed systems, failed processes are often indistinguishable from slow processes. A failure detector is an oracle that can intelligently suspect processes to have failed. Different classes of failure detectors have been proposed to solve different kinds of problems. Almost all of this work is focused on global failure detection, and moreover, in systems that do not contain mobile nodes or include dynamic topologies. In this paper, we present diamPml- a local failure detector that can tolerate mobility and topology changes. This means that diamPmlcan distinguish between a failed process and a process that has moved away from its original location. We also establish an upper bound on the duration for which a process wrongly suspects a node that has moved away from its neighborhood. We support our theoretical results with experimental findings from an implementation of this algorithm for sensor networks

Dynamic module replacement - the ability to hot swap a component's implementation at runtime - is fundamental to supporting evolutionary change in long-lived and highly-available systems. Most existing solutions require special-purpose middleware or depend on research languages with limited support for mainstream software development. We present a language-neutral technique for dynamic module replacement using Service Facilities (Serfs) - a pattern-based design strategy for decoupling runtime dependencies. We demonstrate the sufficiency of Serfs with respect to a litmus test of criteria for module replacement. Next, we extend the traditional scope of module replacement to encompass the domain of modules for distributed protocols. We conclude by applying the Serf strategy to illustrate dynamic replacement of mutual exclusion protocols in modules for distributed resource allocation.