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Communications of the ACM

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CARIN: Wireless CSI-based Driver Activity Recognition under the Interference of Passengers

Recent studies have proposed to use the Channel State Information (CSI) of WiFi wireless channel for human gesture recognition. As an important application, CSI-based driver activity recognition in passenger vehicles has received increasing research attention. However, a serious limitation of almost all the existing WiFi-based recognition solutions is that they can only recognize the activity of a single person at a time, because the activities of other people (if performed at the same time) can interfere with the WiFi signals. In a sharp contrast, there can often be one or more passengers in any vehicles.

In this paper, we propose CARIN, CSI-based driver Activity Recognition under the INterference of passengers. CARIN features a combination-based solution that profiles all the possible activity combinations of driver and (one or more) passengers in offline training and then performs recognition online. To attack possible combination explosion, we first leverage in-car pressure sensors to significantly reduce combinations, because there are only limited seating options in a passenger vehicle. We then formulate a distance minimization problem for fast runtime recognition. In addition, a period analysis methodology is designed based on the kNN classifier to recognize activities that have a sequence of body movements, like continuous head nodding due to driver fatigue. Our results in a real car with 3,000 real-world traces show that CARIN can achieve an overall F1 score of 90.9%, and outperforms the three state-of-the-art solutions by 32.2%.


He Is Just Like Me: A Study of the Long-Term Use of Smart Speakers by Parents and Children

Over the past few years, the technological vision of the HCI and UbiComp communities regarding conversational devices has become manifest in the form of smart speakers such as Google Home and Amazon Echo. Even though millions of households have adopted and integrated these devices into their daily lives, we lack a deep understanding of how different members of a household use such devices. To this end, we conducted interviews with 18 families and collected their Google Home Activity logs to understand the usage patterns of adults and children. Our findings reveal that there are substantial differences in the ways smart speakers are used by adults and children in families over an extended period of time. We report on how parents influence children's use and how different users perceive the devices. Finally, we discuss the implications of our findings and provide guidelines for improving the design of future smart speakers and conversational agents.


WristLens: Enabling Single-Handed Surface Gesture Interaction for Wrist-Worn Devices Using Optical Motion Sensor

WristLens is a system for surface interaction from wrist-worn wearable devices such as smartwatches and fitness trackers. It enables eyes-free, single-handed gestures on surfaces, using an optical motion sensor embedded in a wrist-strap. This allows the user to leverage any proximate surface, including their own body, for input and interaction. An experimental study was conducted to measure the performance of gesture interaction on three different body parts. Our results show that directional gestures are accurately recognized but less so for shape gestures. Finally, we explore the interaction design space enabled by WristLens, and demonstrate novel use cases and applications, such as on-body interaction, bimanual interaction, cursor control and 3D measurement.


Investigating Expectations for Voice-based and Conversational Argument Search on the Web

Millions of arguments are shared on the web. Future information systems will be able to exploit this valuable knowledge source and to retrieve arguments relevant and convincing to our specific need---all with an interface as intuitive as asking your friend "Why ...". Although recent advancements in argument mining, conversational search, and voice recognition have put such systems within reach, many questions remain open, especially on the interface side. In this regard the paper at hand presents the first study of argument search behavior. We conduct an online-survey and a focused user study, putting emphasis on what people expect argument search to be like, rather than on what current first-generation systems provide. Our participants expected to use voice-based argument search mostly at home, but also together with others. Moreover, they expect such search systems to provide rich information on retrieved arguments, such as the source, supporting evidence, and background knowledge on entities or events mentioned. In observed interactions with a simulated system we found that the participants adapted their search behavior to different types of tasks, and that up-front categorization of the retrieved arguments is perceived as helpful if this is short. Our findings are directly applicable to the design of argument search systems, not only voice-based ones.


Submatrix Maximum Queries in Monge and Partial Monge Matrices Are Equivalent to Predecessor Search

We present an optimal data structure for submatrix maximum queries in n× n Monge matrices. Our result is a two-way reduction showing that the problem is equivalent to the classical predecessor problem in a universe of polynomial size. This gives a data structure of O(n) space that answers submatrix maximum queries in O(log log n) time, as well as a matching lower bound, showing that O(log log n) query-time is optimal for any data structure of size O(npolylog(n)). Our result settles the problem, improving on the O(log2 n) query time in SODA’12, and on the O(log n) query-time in ICALP’14.

In addition, we show that partial Monge matrices can be handled in the same bounds as full Monge matrices. In both previous results, partial Monge matrices incurred additional inverse-Ackermann factors.


SIGCSE '20: Proceedings of the 51st ACM Technical Symposium on Computer Science Education

Welcome to the 51st SIGCSE Technical Symposium on Computer Science Education (the 2020 Symposium), the premiere technical conference for computing educators. The 2020 Symposium is sponsored by the Association for Computing Machinery (ACM) Special Interest Group on Computer Science Education (SIGCSE).

SIGCSE has the third largest membership of any of ACM's Special Interest Groups (SIG), and is among the oldest SIGs. Only ten SIGs were founded prior to 1968 when SIGCSE was formed. Last year, we marked the 50th anniversary of the Symposium. Only six SIGs have held conferences with 50+ iterations. We truly have a history to celebrate and we did celebrate with a series of events that honored our past and we are coming into 2020 looking forward to our next 50 years.

One of the most exciting things about the Symposium is the fact that it continues to grow. I made a bold prediction last year that we will see 2020 attendance in 2020. Our submission rates for this year's conference broke records again. The conference organizing committee rose to the challenge of accommodating the clear demand from the community while maintaining the character of a conference that so many look forward to each year by adding a full session of papers, panels, and special sessions after the traditional Saturday lunch. As our community continues to grow, these challenges will continue to face our conference. The board and the conference organizing committees are continually looking for ways to incorporate growth while maintaining the character of our event. The Symposium is about the people, community, and a desire to become better computing educators and it is important to celebrate and honor that every year.

Speaking of the SIGCSE Board, I would like to take a moment to remind everyone that this is the first conference for the new SIGCSE Board (2019-2022). All of the members of the current board are at the conference and are very interested in hearing what we as a board can do for the community during our term on the board. Please feel free to reach out during the conference or after with feedback to the board about the event or any other aspect of SIGCSE.

As an attendee, it is often difficult to imagine the amount of time and effort needed to put together an event the size of the Symposium. There are countless hours, handling crises that arise (big and small), and coordinating a committee of nearly 100 volunteers that help shape the program and events of the conference. It truly is a dedication to the community and the conference that motivates Symposium chairs to do their job. While it may be my honor on behalf of the SIGCSE organization and Board to be the first to thank them for their hard work this past year, I would like to not be the last. Feel free to reach out to the conference co-chairs Jian Zhang and Mark Sherriff and program co-chairs Sarah Heckman, Pamela Cutter and Alvaro Monge and thank them as you see them over the next few days.

Our conference provides us with a chance to honor two people for their contributions to computer science education and the SIGCSE community. The annual SIGCSE award for Outstanding Contribution to Computer Science Education will be given to Lauri Malmi (Aalto University/Helsinki University of Technology). Lauri is world leader in computer science education research focusing on automatic assessment and program and algorithmic visualization. For over 20 years, he has been producing high quality publications and has won several awards, most recently, the best paper award at ICER 2019. He has also supervised 17 iv computing education PhD students. Starting in his native Finland, Lauri has led initiatives to disseminate computing education tools and research among university faculty. However, his reach is much larger, including his work to expand the Koli Calling conference to be an international venue for computer science education research, his work with the Scandinavian Pedagogy of Programming network and his editorial board work (ACM Inroads, ACM TOCE, IEEE Transactions on Learning Technologies). Lauri was also co-chair of ICER 2016 and 2017 and helped to lead major changes to the structure and reviewing for the conference. Lauri has truly helped to shape the global computing education community.


Promoting Collaborative Skills with Github Project Boards

Teamwork skills are much in demand in the workplace, even more so with the growth of Agile methods. This calls for giving Computer Science students more practice in the kinds of team scenarios they will encounter on the job. Key for success are hands-on experience with planning methods, prioritization techniques, time management and organization. This poster shows how the cooperative tracking tool Github Project Boards helps teams strategize development, track progress, distribute work evenly, and facilitate collaboration. It also shows how instructors can use Github Project Boards to visualize and evaluate a team's development process.


Identifying the Prevalence of the Impostor Phenomenon Among Computer Science Students

The Impostor Phenomenon (IP) is often discussed as a problem in the field of computer science, but there has yet to be an empirical study to establish its prevalence among CS students. One survey by the Blind app found that a high number of software engineers at some of the largest technology companies self-reported feelings of Impostor Syndrome; however, self-reporting of Impostor Syndrome is not the standard diagnostic for identifying whether an individual exhibits feelings of the Impostor Phenomenon. In this work, the established Clance IP Scale is used to identify the prevalence of IP among graduate and undergraduate computer science students at a large research-intensive North American institution. Among this population of over 200 students, 57% were found to exhibit frequent feelings of the Impostor Phenomenon with a larger fraction of women (71%) experiencing frequent feelings of the Imposter Phenomenon than men (52%). Additionally, IP was found to have greater prevalence among computer science students than among students of other populations from comparable studies. Due to the negative impacts associated with feelings of the Impostor Phenomenon, computer science education should work to improve student awareness and help student cope with these feelings.


When Twice as Good Isn't Enough: The Case for Cultural Competence in Computing

The commonly documented diversity, equity, and inclusion (DEI) issues in the computing workforce are the direct result of corporate cultures that benefit specific groups and marginalize others. This culture usually begins in undergraduate computing departments, where the demographic representation mirrors that of industry. With no formal courses that focus on the non-technical issues affecting marginalized groups and how to address and eradicate them, students are indirectly taught that the current status quo in computing departments and industry is not only acceptable, but also unproblematic. This directly affects students from marginalized groups (as the reasons for attrition are similar in both higher education and industry), as well as faculty (as biased student evaluations directly affect hiring, promotion, and tenure decisions). This position paper presents the need for cultural competence as a required focus for university computing departments nationwide. By improving these issues before students complete baccalaureate computing degrees, companies will have talent pools that better understand the importance and necessity of DEI and also work to ensure they help foster a more diverse, equitable, and inclusive environment. In addition, more students from marginalized groups will be retained in the major through degree completion.


PPoPP '20: Proceedings of the 25th ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming

It is our great pleasure to welcome you to PPoPP 2020, the 25th ACM Symposium on Principles and Practice of Parallel Programming, in San Diego, USA. PPOPP is the premier forum for leading work on all aspects of parallel programming, including theoretical foundations, techniques, languages, compilers, runtime systems, tools, and practical experience. Given the rise of parallel architectures in the consumer market (desktops, laptops, and mobile devices) and data centers, we made an effort to attract work that addresses new parallel workloads and issues that arise out of extreme-scale applications or cloud platforms, as well as techniques and tools that improve the productivity of parallel programming or work towards improved synergy with such emerging architectures.