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Exquisitor at the Lifelog Search Challenge 2021 : Relationships between Semantic Classifiers
(Association for Computing Machinery, Inc, 2021-08-21) Khan, Omar Shahbaz; Duane, Aaron; Jónsson, Björn Þór; Zahálka, Jan; Rudinac, Stevan; Worring, Marcel; Department of Computer Science
Exquisitor is a scalable media exploration system based on interactive learning. To satisfy a user's information need, the system asks the user for feedback on media items and uses that feedback to interactively construct a classifier, that is in turn used to identify the next potentially relevant set of media items. To facilitate effective exploration of a collection, the system offers filters to narrow the scope of exploration, search functionality for finding good examples for the classifier, and support for timeline browsing of videos or image sequences. For this year's Lifelog Search Challenge, we have enhanced Exquisitor to better support tasks with a temporal component, by adding features that allow the user to build multiple classifiers and merge the classifier results, using both traditional set operators and advanced temporal operators.
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Is the Reign of Interactive Search Eternal? Findings from the Video Browser Showdown 2020
(2021-08) Lokoč, Jakub; Veselý, Patrik; Mejzlík, František; Kovalčík, Gregor; Souček, Tomáš; Rossetto, Luca; Schoeffmann, Klaus; Bailer, Werner; Gurrin, Cathal; Sauter, Loris; Song, Jaeyub; Vrochidis, Stefanos; Wu, Jiaxin; Jónsson, Björn Þór; Department of Computer Science
Comprehensive and fair performance evaluation of information retrieval systems represents an essential task for the current information age. Whereas Cranfield-based evaluations with benchmark datasets support development of retrieval models, significant evaluation efforts are required also for user-oriented systems that try to boost performance with an interactive search approach. This article presents findings from the 9th Video Browser Showdown, a competition that focuses on a legitimate comparison of interactive search systems designed for challenging known-item search tasks over a large video collection. During previous installments of the competition, the interactive nature of participating systems was a key feature to satisfy known-item search needs, and this article continues to support this hypothesis. Despite the fact that top-performing systems integrate the most recent deep learning models into their retrieval process, interactive searching remains a necessary component of successful strategies for known-item search tasks. Alongside the description of competition settings, evaluated tasks, participating teams, and overall results, this article presents a detailed analysis of query logs collected by the top three performing systems, SOMHunter, VIRET, and vitrivr. The analysis provides a quantitative insight to the observed performance of the systems and constitutes a new baseline methodology for future events. The results reveal that the top two systems mostly relied on temporal queries before a correct frame was identified. An interaction log analysis complements the result log findings and points to the importance of result set and video browsing approaches. Finally, various outlooks are discussed in order to improve the Video Browser Showdown challenge in the future.
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Naked and on fire : Examining player agency experiences in narrative-focused gameplay
(Association for Computing Machinery, 2021-05-06) Carstensdottir, Elin; Kleinman, Erica; Williams, Ryan; El-Nasr, Magy Seif; Department of Computer Science
Player agency is central to interactive narrative and games. While previous work focuses on analyzing player perception of agency through various lenses and phenomena, like meaningful choice and expectations, it is largely theoretical. Few user studies within games explore how players reason about and judge their own agency within interactive narratives.We present an interview study where participants rated their agency experiences within narrativefocused games and described their reasoning. The analysis suggests that agency perception depends on multiple factors beyond meaningful choice, such as social investment and genre-conventions. Participants described varying preferences and value judgements for different factors, indicating that individual differences have a deep impact on agency perception in narrative-focused gameplay. We discuss the implications of these cognitive variables on design, how they can be leveraged with other factors, and how our findings can help future work enhance and measure player agency, within interactive narrative and beyond.
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Sleep and the athlete : Narrative review and 2021 expert consensus recommendations
(2021-04-01) Walsh, Neil P.; Halson, Shona L.; Sargent, Charli; Roach, Gregory D.; Nédélec, Mathieu; Gupta, Luke; Leeder, Jonathan; Fullagar, Hugh H.; Coutts, Aaron J.; Edwards, Ben J.; Pullinger, Samuel A.; Robertson, Colin M.; Burniston, Jatin G.; Lastella, Michele; Le Meur, Yann; Hausswirth, Christophe; Bender, Amy M.; Grandner, Michael A.; Samuels, Charles H.; Department of Sport Science
Elite athletes are particularly susceptible to sleep inadequacies, characterised by habitual short sleep (<7 hours/night) and poor sleep quality (eg, sleep fragmentation). Athletic performance is reduced by a night or more without sleep, but the influence on performance of partial sleep restriction over 1-3 nights, a more real-world scenario, remains unclear. Studies investigating sleep in athletes often suffer from inadequate experimental control, a lack of females and questions concerning the validity of the chosen sleep assessment tools. Research only scratches the surface on how sleep influences athlete health. Studies in the wider population show that habitually sleeping <7 hours/night increases susceptibility to respiratory infection. Fortunately, much is known about the salient risk factors for sleep inadequacy in athletes, enabling targeted interventions. For example, athlete sleep is influenced by sport-specific factors (relating to training, travel and competition) and non-sport factors (eg, female gender, stress and anxiety). This expert consensus culminates with a sleep toolbox for practitioners (eg, covering sleep education and screening) to mitigate these risk factors and optimise athlete sleep. A one-size-fits-All approach to athlete sleep recommendations (eg, 7-9 hours/night) is unlikely ideal for health and performance. We recommend an individualised approach that should consider the athlete's perceived sleep needs. Research is needed into the benefits of napping and sleep extension (eg, banking sleep).
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Circularly Polarized Dielectric Resonator Antenna with Two Annular Vias
(2021) Elahi, Manzoor; Altaf, Amir; Yang, Youngoo; Lee, Kang Yoon; Hwang, Keum Cheol; Department of Engineering
In this paper, a new technique for circular polarization in a slot coupled dielectric resonator antenna is proposed. The circular polarization is generated by inserting the two annular vias into dielectric resonator slightly off the diagonal position. In addition to the circular polarization, the proposed technique increases the total realized gain by 1.62 dB as compared to the via-less case on the account of increased directivity while maintaining the same aspect ratio of the DR. To validate the design, a prototype is fabricated and measured. The measured results show that the proposed circularly polarized dielectric resonator antenna has a -10 dB reflection bandwidth of 7.29% (3.3-3.55 GHz) and a 3 dB axial ratio bandwidth of 5.5% (3.28-3.465 GHz) with a measured RHCP gain of 6-7.1 dBic. The measured curves of the S11, axial ratio, and the RHCP gain results are in good agreement with the simulated results.

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