1,816 research outputs found
KBody: Towards general, robust, and aligned monocular whole-body estimation
KBody is a method for fitting a low-dimensional body model to an image. It
follows a predict-and-optimize approach, relying on data-driven model estimates
for the constraints that will be used to solve for the body's parameters.
Acknowledging the importance of high quality correspondences, it leverages
``virtual joints" to improve fitting performance, disentangles the optimization
between the pose and shape parameters, and integrates asymmetric distance
fields to strike a balance in terms of pose and shape capturing capacity, as
well as pixel alignment. We also show that generative model inversion offers a
strong appearance prior that can be used to complete partial human images and
used as a building block for generalized and robust monocular body fitting.
Project page: https://klothed.github.io/KBody.Comment: 11 pages, 6 figures, 58 supplemental figures, project page
https://klothed.github.io/KBody , also posted at with high-res images
http://graphics.berkeley.edu/papers/Zioulis-KBT-2023-0
Results of the 2023 Census of Beat Saber Users: Virtual Reality Gaming Population Insights and Factors Affecting Virtual Reality E-Sports Performance
The emergence of affordable standalone virtual reality (VR) devices has
allowed VR technology to reach mass-market adoption in recent years, driven
primarily by the popularity of VR gaming applications such as Beat Saber.
However, despite being the top-grossing VR application to date and the most
popular VR e-sport, the population of over 6 million Beat Saber users has not
yet been widely studied. In this report, we present a large-scale comprehensive
survey of Beat Saber players (N=1,006) that sheds light on several important
aspects of this population, including their background, biometrics,
demographics, health information, behavioral patterns, and technical device
specifications. We further provide insights into the emerging field of VR
e-sports by analyzing correlations between responses and an authoritative
measure of in-game performance.Comment: for interactive version, see https://www.beatleader.xyz/census202
Arctic Zooplankton Community Structure: Exceptions to Some General Rules
Commonly accepted theories of zooplankton species distribution hold that: 1) large-bodied zooplankton species are excluded by fish predation and so are found only in lakes and ponds without fish; and 2) because small-bodied species are unable to compete successfully against large ones and also are preyed upon heavily by invertebrate predators, they exist primarily in lakes with fish. This pattern is not followed in a group of lakes and ponds in arctic Alaska. Some of these lakes were found to support both large and small zooplankton species along with populations of facultative planktivorous fish. Other lakes that had no fish had a small-bodied zooplankton species co-existing with a more typical large-bodied community. Close analysis of these unusual distributions reveals that the mechanisms affecting zooplankton community dynamics are more subtle and complex than generally recognized, particularly in such harsh environments as the Arctic
Quantum process tomography of a controlled-NOT gate
We demonstrate complete characterization of a two-qubit entangling process -
a linear optics controlled-NOT gate operating with coincident detection - by
quantum process tomography. We use maximum-likelihood estimation to convert the
experimental data into a physical process matrix. The process matrix allows
accurate prediction of the operation of the gate for arbitrary input states,
and calculation of gate performance measures such as the average gate fidelity,
average purity and entangling capability of our gate, which are 0.90, 0.83 and
0.73, respectively.Comment: 4 pages, 2 figures. v2 contains new data corresponding to improved
gate operation. Figure quality slightly reduced for arXi
Unique Identification of 50,000+ Virtual Reality Users from Head & Hand Motion Data
With the recent explosive growth of interest and investment in virtual
reality (VR) and the so-called "metaverse," public attention has rightly
shifted toward the unique security and privacy threats that these platforms may
pose. While it has long been known that people reveal information about
themselves via their motion, the extent to which this makes an individual
globally identifiable within virtual reality has not yet been widely
understood. In this study, we show that a large number of real VR users
(N=55,541) can be uniquely and reliably identified across multiple sessions
using just their head and hand motion relative to virtual objects. After
training a classification model on 5 minutes of data per person, a user can be
uniquely identified amongst the entire pool of 50,000+ with 94.33% accuracy
from 100 seconds of motion, and with 73.20% accuracy from just 10 seconds of
motion. This work is the first to truly demonstrate the extent to which
biomechanics may serve as a unique identifier in VR, on par with widely used
biometrics such as facial or fingerprint recognition
Consistent improvement with eculizumab across muscle groups in myasthenia gravis
Objective: To assess whether eculizumab, a terminal complement inhibitor, improves patient- and physician-reported outcomes (evaluated using the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale, respectively) in patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis across four domains, representing ocular, bulbar, respiratory, and limb/gross motor muscle groups. Methods: Patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis were randomized 1:1 to receive either placebo or eculizumab during the REGAIN study (NCT01997229). Patients who completed REGAIN were eligible to continue into the open-label extension trial (NCT02301624) for up to 4 years. The four domain scores of each of the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale recorded throughout REGAIN and through 130 weeks of the open-label extension were analyzed. Results: Of the 125 patients who participated in REGAIN, 117 enrolled in the open-label extension; 61 had received placebo and 56 had received eculizumab during REGAIN. Patients experienced rapid improvements in total scores and all four domain scores of both the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale with eculizumab treatment. These improvements were sustained through 130 weeks of the open-label extension. Interpretation: Eculizumab treatment elicits rapid and sustained improvements in muscle strength across ocular, bulbar, respiratory, and limb/gross motor muscle groups and in associated daily activities in patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis
Altering fatty acid availability does not impair prolonged, continuous running to fatigue: evidence for carbohydrate dependence
We determined the effect of suppressing lipolysis via administration of nicotinic acid (NA) on fuel substrate selection and half-marathon running capacity. In a single-blinded, Latin square design, 12 competitive runners completed four trials involving treadmill running until volitional fatigue at a pace based on 95% of personal best half-marathon time. Trials were completed in a fed or overnight fasted state: 1) carbohydrate (CHO) ingestion before (2 g CHO·kg−1·body mass−1) and during (44 g/h) [CFED]; 2) CFED plus NA ingestion [CFED-NA]; 3) fasted with placebo ingestion during [FAST]; and 4) FAST plus NA ingestion [FAST-NA]. There was no difference in running distance (CFED, 21.53 ± 1.07; CFED-NA, 21.29 ± 1.69; FAST, 20.60 ± 2.09; FAST-NA, 20.11 ± 1.71 km) or time to fatigue between the four trials. Concentrations of plasma free fatty acids (FFA) and glycerol were suppressed following NA ingestion irrespective of preexercise nutritional intake but were higher throughout exercise in FAST compared with all other trials (P < 0.05). Rates of whole-body CHO oxidation were unaffected by NA ingestion in the CFED and FAST trials, but were lower in the FAST trial compared with the CFED-NA trial (P < 0.05). CHO was the primary substrate for exercise in all conditions, contributing 83-91% to total energy expenditure with only a small contribution from fat-based fuels. Blunting the exercise-induced increase in FFA via NA ingestion did not impair intense running capacity lasting ∼85 min, nor did it alter patterns of substrate oxidation in competitive athletes. Although there was a small but obligatory use of fat-based fuels, the oxidation of CHO-based fuels predominates during half-marathon running
Inferring Private Personal Attributes of Virtual Reality Users from Head and Hand Motion Data
Motion tracking "telemetry" data lies at the core of nearly all modern
virtual reality (VR) and metaverse experiences. While generally presumed
innocuous, recent studies have demonstrated that motion data actually has the
potential to uniquely identify VR users. In this study, we go a step further,
showing that a variety of private user information can be inferred just by
analyzing motion data recorded by VR devices. We conducted a large-scale survey
of VR users (N=1,006) with dozens of questions ranging from background and
demographics to behavioral patterns and health information. We then collected
VR motion samples of each user playing the game ``Beat Saber,'' and attempted
to infer their survey responses using just their head and hand motion patterns.
Using simple machine learning models, many of these attributes could accurately
and consistently be inferred from VR motion data alone, highlighting the
pressing need for privacy-preserving mechanisms in multi-user VR applications
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