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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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Full-Waveform based methods for Microseismic Monitoring Operations : An Application to Natural and Induced Seismicity in the Hengill Geothermal Area, Iceland
(2020-11-19) Rossi, Camilla; Grigoli, Francesco; Cesca, Simone; Heimann, Sebastian; Gasperini, Paolo; Hjörleifsdóttir, Vala; Dahm, Torsten; Bean, Christopher J.; Wiemer, Stefan; Scarabello, Luca; Nooshiri, Nima; Clinton, John F.; Obermann, Anne; Ágústsson, Kristján; Ágústsdóttir, Thorbjörg; Department of Engineering
Geothermal systems in the Hengill volcanic area, SW Iceland, started to be exploited for electrical power and heat production since the late 1960s. Today the two largest operating geothermal power plants are located at Nesjavellir and Hellisheiði. This area is a complex tectonic and geothermal site, located at the triple junction between the Reykjanes Peninsula (RP), the Western Volcanic Zone (WVZ), and the South Iceland Seismic Zone (SISZ). The region is seismically highly active with several thousand earthquakes located yearly. The origin of such earthquakes may be either natural or anthropogenic. The analysis of microseismicity can provide useful information on natural active processes in tectonic, geothermal and volcanic environments as well as on physical mechanisms governing induced events. Here, we investigate the microseismicity occurring in Hengill area, using a very dense broadband seismic monitoring network deployed in Hellisheiði since November 2018, and apply sophisticated full-waveform based method for detection and location. Improved locations and first characterization indicate that it is possible to identify different types of microseismic clusters, which are associated with either production/injection or the tectonic setting of the geothermal area.
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Synchronizer-Free Digital Link Controller
(2020-10) Bund, Johannes; Fugger, Matthias; Lenzen, Christoph; Medina, Moti; Department of Computer Science
This work presents a producer-consumer link between two independent clock domains. The link allows for metastability-free, low-latency, high-throughput communication by slight adjustments to the clock frequencies of the producer and consumer domains steered by a controller circuit. Any such controller cannot deterministically avoid, detect, nor resolve metastability. Typically, this is addressed by synchronizers, incurring a larger dead time in the control loop. We follow the approach of Friedrichs et al. (TC 2018) who proposed metastability-containing circuits. The result is a simple control circuit that may become metastable, yet deterministically avoids buffer underrun or overflow. More specifically, the controller output may become metastable, but this may only affect oscillator speeds within specific bounds. In contrast, communication is guaranteed to remain metastability-free. We formally prove correctness of the producer-consumer link and a possible implementation that has only small overhead. With SPICE simulations of the proposed implementation we further substantiate our claims. The simulation uses 65nm process running at roughly 2GHz.
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A (Visual) Novel Route to Learning : A Taxonomy of Teaching Strategies in Visual Novels
(Association for Computing Machinery, 2020-09-15) Camingue, Janelynn; Melcer, Edward F.; Carstensdottir, Elin; Yannakakis, Georgios N.; Liapis, Antonios; Penny, Kyburz; Volz, Vanessa; Khosmood, Foaad; Lopes, Phil; Department of Computer Science
Interactive narratives are widely used to frame and contextualize education in games. However, the specifics of how their designs aid the learning process and outcomes remains relatively unexplored. To better understand this space, a study was conducted that focused on one sub-genre of interactive narrative, Visual Novels. Specifically, in this paper we conducted a survey of thirty-one existing educational Visual Novels, analyzing design elements that fostered learning and delivered educational content. The resulting taxonomy consists of five key dimensions for educational design and teaching strategies within Visual Novels: 1) Teaching Through Choice, 2) Teaching Through Scripted Sequences, 3) Teaching Through Mini-games, 4) Teaching Through Exploration and 5) Non-interactive Teaching. These dimensions demonstrate that there are a number of design considerations for supporting learning through Visual Novels. This work has implications for designers of educational games by classifying the different designs a Visual Novel can employ to teach-ultimately informing how to better present educational subject matter in interactive narrative games.
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Introduction to the third annual lifelog search challenge (LSC'20)
(Association for Computing Machinery, 2020-06-11) Gurrin, Cathal; Le, Tu Khiem; Ninh, Van Tu; Dang-Nguyen, Duc Tien; Jónsson, Björn Þór; Lokoš, Jakub; Hürst, Wolfgang; Tran, Minh Triet; Schöffmann, Klaus; Department of Computer Science
The Lifelog Search Challenge (LSC) is an annual comparative benchmarking activity for comparing approaches to interactive retrieval from multi-modal lifelogs. LSC'20, the third such challenge, attracts fourteen participants with their interactive lifelog retrieval systems. These systems are comparatively evaluated in front of a live-audience at the LSC workshop at ACM ICMR'20 in Dublin, Ireland. This overview motivates the challenge, presents the dataset and system configuration used in the challenge, and briefly presents the participating teams.

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