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1. Systems Thinking Assessments: Approaches That Examine Engagement in Systems Thinking

   Dugan. K. E., Mosyjowski (January 2021, Proceedings of the 2021 American Society for Engineering Education Annual Conference & Exposition)

   null (Ed.)

   While systems engineers rely on systems thinking skills in their work, given the increasing complexity of modern engineering problems, engineers across disciplines need to be able to engage in systems thinking, including what we term comprehensive systems thinking. Due to the inherent complexity of systems thinking, and more specifically comprehensive systems thinking, it is not easy to know how well students (and practitioners) are learning and leveraging systems thinking approaches. Thus, engineering managers and educators can benefit from systems thinking assessments. A variety of systems thinking assessments exist that are relevant to engineers, including some focused on the demonstration of systems thinking knowledge or skills and others measuring attitudes, interests, or values related to systems thinking. Starting with a collection of systems thinking assessments from a systematic literature review conducted by our team, we analyzed in-depth those behavior-based assessments that included the creation of a visual representation and were open-ended, i.e., it did not presuppose or provide answers. The findings from this in-depth analysis of systems thinking behavior-based assessments identified 1) six visualization types that were leveraged, 2) dimensions of systems thinking that were assessed and 3) tensions between the affordances of different assessments. In addition, we consider the ways assessments can be used. For example, using assessments to provide feedback to students or using assessments to determine which students are meeting defined learning goals. We draw on our findings to highlight opportunities for future comprehensive systems thinking behavior-based assessment development. 

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2. A quantitative analysis of system bottlenecks in visual SLAM

   https://doi.org/10.1145/3508396.3512882  

   Semenova, Sofiya; Ko, Steven Y.; Liu, Yu David; Ziarek, Lukasz; Dantu, Karthik (March 2022, Proceedings of the 23rd Annual International Workshop on Mobile Computing Systems and Applications)

   Visual SLAM systems are concurrent, performance-critical systems that respond to real-time environmental conditions and are frequently deployed on resource-constrained hardware. Previous SLAM frameworks have primarily focused on algorithmic advances and their systems core has largely remained unchanged. In turn, SLAM systems suffer from performance problems that could be alleviated with improved systems design. In this paper, we present a quantitative analysis of the systems challenges to building consistent, accurate, and robust SLAM systems in the face of concurrency, variable environmental conditions, and resource-constrained hardware. We identify three interconnected challenges on systems design --- timeliness, concurrency, and context awareness --- and clarify their effects on performance. 

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3. Survey of Control-flow Integrity Techniques for Real-time Embedded Systems

   https://doi.org/10.1145/3538275  

   Mishra, Tanmaya; Chantem, Thidapat; Gerdes, Ryan (July 2022, ACM Transactions on Embedded Computing Systems)

   Computing systems, including real-time embedded systems, are becoming increasingly connected to allow for more advanced and safer operation. Such embedded systems are also often resource-constrained, for example, with lower processing capabilities compared to general-purpose computing systems like desktops or servers. With the advent of paradigms such as internet-of-things (IoT), embedded systems in both commercial and industrial contexts are being increasingly interconnected and exposed to the external networks to improve automation and efficiency of operation. However, allowing external interfaces to such embedded systems increases their exposure to attackers. With an increase in attacks against embedded systems ranging from home appliances to industrial control systems operating critical equipment that have real-time requirements, it is imperative that defense mechanisms be created that explicitly consider such resource and real-time constraints. Control-flow integrity (CFI) is a family of defense mechanisms that prevent attackers from modifying the flow of execution. We survey CFI techniques, ranging from the basic to state of the art, that are built for embedded systems and real-time embedded systems and find that there is a dearth, especially for real-time embedded systems, of CFI mechanisms. We then present open challenges to the community to help drive future research in this domain. 

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4. DepFast: Orchestrating Code of Quorum Systems

   Luo, Xuhao; Shen, Weihai; Mu, Shuai; Xu, Tianyin (July 2022, Proceedings of the 2022 USENIX Annual Technical Conference)

   Quorum systems (e.g., replicated state machines) are critical distributed systems. Building correct, high-performance quorum systems is known to be hard. A major reason is that the protocols in quorum systems lead to non-deterministic state changes and complex branching conditions based on different events (e.g., timeouts). Traditionally, these systems are built with an asynchronous coding style with event-driven callbacks, but often lead to “callback hell” that makes code hard to follow and maintain. Converting to synchronous coding styles (e.g., using coroutines) is challenging because of the complex branching conditions. In this paper, we present Dependably Fast (DepFast), an effective, expressive framework for developing quorum systems. DepFast provides a unique QuorumEvent abstraction to enable building quorum systems in a synchronous style. It also supports composition of multiple events, e.g., timeouts, different quorums. To evaluate DepFast, we use it to implement two quorum systems, Raft and Copilot. We show that complex quorum systems implemented by DepFast are easy to write and have high performance. Specifically, it takes 25%–35% fewer lines of code to implement Raft and Copilot using DepFast, and the DepFast-based implementations have comparable performance with the state-of-the-art systems. 

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5. DepFast: Orchestrating Code of Quorum Systems

   Luo, Xuhao; Shen, Weihai; Mu, Shuai; Xu, Tianyin (July 2022, Proceedings of the 2022 USENIX Annual Technical Conference)

   Quorum systems (e.g., replicated state machines) are critical distributed systems. Building correct, high-performance quorum systems is known to be hard. A major reason is that the protocols in quorum systems lead to non-deterministic state changes and complex branching conditions based on different events (e.g., timeouts). Traditionally, these systems are built with an asynchronous coding style with event-driven callbacks, but often lead to “callback hell” that makes code hard to follow and maintain. Converting to synchronous coding styles (e.g., using coroutines) is challenging because of the complex branching conditions. In this paper, we present Dependably Fast (DepFast), an effective, expressive framework for developing quorum systems. DepFast provides a unique QuorumEvent abstraction to enable building quorum systems in a synchronous style. It also supports composition of multiple events, e.g., timeouts, different quorums. To evaluate DepFast, we use it to implement two quorum systems, Raft and Copilot. We show that complex quorum systems implemented by DepFast are easy to write and have high performance. Specifically, it takes 25%–35% fewer lines of code to implement Raft and Copilot using DepFast, and the DepFast-based implementations have comparable performance with the state-of-the-art systems. 

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