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Creators/Authors contains: "Liu, Frank"

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  1. Smart IoT Speakers, while connected over a network, currently only produce sounds that come directly from the individual devices. We envision a future where smart speakers collaboratively produce a fabric of spatial audio, capable of perceptually placing sound in a range of locations in physical space. This could provide audio cues in homes, offices and public spaces that are flexibly linked to various positions. The perception of spatialized audio relies on binaural cues, especially the time difference and the level difference of incident sound at a user’s left and right ears. Traditional stereo speakers cannot create the spatialization perception for a user when playing binaural audio due to auditory crosstalk, as each ear hears a combination of both speaker outputs. We present Xblock, a novel time-domain pose-adaptive crosstalk cancellation technique that creates a spatial audio perception over a pair of speakers using knowledge of the user’s head pose and speaker positions. We build a prototype smart speaker IoT system empowered by Xblock, explore the effectiveness of Xblock through signal analysis, and discuss future perceptual user studies and future work. 
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  2. Researchers, educators, and multimedia designers need to better understand how mixing physical tangible objects with virtual experiences affects learning and science identity. In this novel study, a 3D-printed tangible that is an accurate facsimile of the sort of expensive glassware that chemists use in real laboratories is tethered to a laptop with a digitized lesson. Interactive educational content is increasingly being placed online, it is important to understand the educational boundary conditions associated with passive haptics and 3D-printed manipulables. Cost-effective printed objects would be particularly welcome in rural and low Socio-Economic (SES) classrooms. A Mixed Reality (MR) experience was created that used a physical 3D-printed haptic burette to control a computer-based chemistry titration experiment. This randomized control trial study with 136 college students had two conditions: 1) low-embodied control (using keyboard arrows), and 2) high-embodied experimental (physically turning a valve/stopcock on the 3D-printed burette). Although both groups displayed similar significant gains on the declarative knowledge test, deeper analyses revealed nuanced Aptitude by Treatment Interactions (ATIs). These interactionsfavored the high-embodied experimental group that used the MR devicefor both titration-specific posttest knowledge questions and for science efficacy and science identity. Those students with higher prior science knowledge displayed higher titration knowledge scores after using the experimental 3D-printed haptic device. A multi-modal linguistic and gesture analysis revealed that during recall the experimental participants used the stopcock-turning gesture significantly more often, and their recalls created a significantly different Epistemic Network Analysis (ENA). ENA is a type of 2D projection of the recall data, stronger connections were seen in the high embodied group mainly centering on the key hand-turning gesture. Instructors and designers should consider the multi-modal and multi-dimensional nature of the user interface, and how the addition of another sensory-based learning signal (haptics) might differentially affect lower prior knowledge students. One hypothesis is that haptically manipulating novel devices during learning may create more cognitive load. For low prior knowledge students, it may be advantageous for them to begin learning content on a more ubiquitous interface (e.g., keyboard) before moving them to more novel, multi-modal MR devices/interfaces. 
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  3. What we feel from handling liquids in vessels produces unmistakably fluid tactile sensations. These stimulate essential perceptions in home, laboratory, or industrial contexts. Feeling fluid interactions from virtual fluids would similarly enrich experiences in virtual reality. We introduce Geppetteau, a novel string-driven weight shifting mechanism capable of providing perceivable tactile sensations of handling virtual liquids within a variety of vessel shapes. These mechanisms widen the range of augmentable shapes beyond the state-of-the-art of existing mechanical systems. In this work, Geppetteau is integrated into conical, spherical, cylindrical, and cuboid shaped vessels. Variations of these shapes are often used for fluid containers in our day-to-day. We studied the effectiveness of Geppetteau in simulating fine and coarse-grained tactile sensations of virtual liquids across three user studies. Participants found Geppetteau successful in providing congruent physical sensations of handling virtual liquids in a variety of physical vessel shapes and virtual liquid volumes and viscosities. 
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  4. null (Ed.)
    Augmented Reality (AR) is becoming readily more available as the number of AR capable smartphones and tablets increase in popularity. With its exponential development, augmented reality offers an oppurtunity to facilitate education in online chemistry. In hopes of furthering the advancement of augmented reality in online chemistry education, we developed a boiling water experiment to show the effects of heat capacity and to create an interactive lab experiment for online learning. Our work-in-progress paper explores how the utilization of augmented reality can improve the learning process and better exhibit chemistry lab concepts. 
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  5. Current VR/AR systems are unable to reproduce the physical sensation of fluid vessels, due to the shifting nature of fluid motion. To this end, we introduce SWISH, an ungrounded mixed-reality interface, capable of affording the users a realistic haptic sensation of fluid behaviors in vessels. The chief mechanism behind SWISH is in the use of virtual reality tracking and motor actuation to actively relocate the center of gravity of a handheld vessel, emulating the moving center of gravity of a handheld vessel that contains fluid. In addition to solving challenges related to reliable and efficient motor actuation, our SWISH designs place an emphasis on reproducibility, scalability, and availability to the maker culture. Our virtual-to-physical coupling uses Nvidia Flex's Unity integration for virtual fluid dynamics with a 3D printed augmented vessel containing a motorized mechanical actuation system. To evaluate the effectiveness and perceptual efficacy of SWISH, we conduct a user study with 24 participants, 7 vessel actions, and 2 virtual fluid viscosities in a virtual reality environment. In all cases, the users on average reported that the SWISH bucket generates accurate tactile sensations for the fluid behavior. This opens the potential for multi-modal interactions with programmable fluids in virtual environments for chemistry education, worker training, and immersive entertainment. 
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  6. Measurements are presented of the cross-section for the central exclusive production ofJ/\psi\to\mu^+\mu^- J / ψ μ + μ and\psi(2S)\to\mu^+\mu^- ψ ( 2 S ) μ + μ processes in proton-proton collisions at\sqrt{s} = 13 \ \mathrm{TeV} s = 13 T e V with 2016–2018 data. They are performed by requiring both muons to be in the LHCb acceptance (with pseudorapidity2<\eta_{\mu^±} < 4.5 2 < η μ ± < 4.5 ) and mesons in the rapidity range2.0 < y < 4.5 2.0 < y < 4.5 . The integrated cross-section results are\sigma_{J/\psi\to\mu^+\mu^-}(2.0 σ J / ψ μ + μ ( 2.0 < y J / ψ < 4.5 , 2.0 < η μ ± < 4.5 ) = 400 ± 2 ± 5 ± 12 p b , σ ψ ( 2 S ) μ + μ ( 2.0 < y ψ ( 2 S ) < 4.5 , 2.0 < η μ ± < 4.5 ) = 9.40 ± 0.15 ± 0.13 ± 0.27 p b , where the uncertainties are statistical, systematic and due to the luminosity determination. In addition, a measurement of the ratio of\psi(2S) ψ ( 2 S ) andJ/\psi J / ψ cross-sections, at an average photon-proton centre-of-mass energy of1\ \mathrm{TeV} 1 T e V , is performed, giving$ = 0.1763 ± 0.0029 ± 0.0008 ± 0.0039,$$ where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the involved branching fractions. For the first time, the dependence of theJ/\psi$ J / ψ and\psi(2S) ψ ( 2 S ) cross-sections on the total transverse momentum transfer is determined inpp p p collisions and is found consistent with the behaviour observed in electron-proton collisions. 
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    Free, publicly-accessible full text available January 1, 2026