bluuebunny/crossref_metadata_2025 huggingface dataset:
Case for mandatory COVID-19 vaccinations for workers in health and aged care settings: a guide for leaders
Authors: Loh Erwin , Michael Sarah , Beetson Rob , Schmidt Annie
Published: December 2021

Background

This brief paper provides an overview of the analysis in support of mandating COVID-19 vaccinations for all workers in health and aged care settings in Australia. Leaders of health and aged care organisations have a duty of care under work health and safety legislation to eliminate and/or control the risk of transmission of vaccine-preventable disease in their facilities, including COVID-19.

Methods

Key issues that should be considered by healthcare leaders when mandating that all health and aged care workers be vaccinated against COVID-19 were analysed by executives from a large Australian national health and aged care provider and discussed in this paper.

Results

This paper summarises the medical/scientific, ethical, legal, work health and safety, workers’ compensation and industrial relations considerations when mandating COVID-19 vaccination for healthcare workers.

Conclusion

Leaders of health and aged care organisations must provide a safe environment and workplace for all those who work for them, as well as for those who receive care or treatment at one of their facilities. It is hoped that this paper will assist leaders of healthcare organisations in making their own decisions during this time.
Combine harvester assembly fault diagnosis based on optimized multi-scale reverse discrete entropy
Authors: Zhao Sixia , Zhang Jiaming , Xu Liyou , Chen Xiaoliang
Published: December 2021

An optimized multi-scale reverse discrete entropy (RDE, OMRDE) method for feature extraction is proposed to address the lack of effective feature extraction and detection methods for combine harvester assembly fault inspection. This method was used to extract the vibration signal features from the combine. A fault diagnostic method is designed to verify the efficiency of the associated methods. First, a comparative study of the RDE, multi-scale inverse DE (MRDE), and OMRDE methods was performed using simulated signals to verify the effectiveness of OMRDE. Second, the FSTPSO–VMD method was used to decompose the vibration signal of the combine assembly fault, and the OMRDE, MRDE, and fuzzy entropy were compared and analyzed. The actual feature extraction effect of the three entropy functions reached the highest classification accuracy (88.5%) after using OMRDE to extract features. Finally, a fusion feature set is constructed to further improve the classification accuracy, and the LSSVM classifier is optimized using FSTPSO. The analytical results show that the FSTPSO–LSSVM classifier constructed in this study adopts the fused feature with an accuracy of 93%, which is better than that of other common methods, and verifies the validity of the fault diagnostic model. Therefore, the performance of the OMRDE method proposed in this study is better than that of the MRDE. The proposed fault diagnostic model can accurately classify the fault detection of a combine harvester assembly.
Masses and strong decays of open charm hexaquark states $$\Sigma _{c}^{(*)}{\Sigma }_{c}^{(*)}$$
Authors: Ling Xi-Zhe , Liu Ming-Zhu , Geng Li-Sheng
Published: December 2021

Inspired by the recent discovery of the doubly charmed tetraquark state $$T_{cc}^{+}$$

T

cc

+

by the LHCb Collaboration, we perform a systematic study of masses and strong decays of open charm hexaquark states $${\Sigma }_{c}^{(*)}\Sigma _{c}^{(*)}$$

Σ

c

(

∗
)

Σ

c

(

∗
)

. Taking into account heavy quark spin symmetry breaking, we predict several bound states of isospin $$I=0$$

I
=
0

, $$I=1$$

I
=
1

, and $$I=2$$

I
=
2

in the one boson exchange model. Moreover, we adopt the effective Lagrangian approach to estimate the decay widths of $${\Sigma }_{c}^{(*)}\Sigma _{c}^{(*)} \rightarrow \Lambda _{c}\Lambda _{c}$$

Σ

c

(

∗
)

Σ

c

(

∗
)

→

Λ
c

Λ
c

and their relevant ratios via the triangle diagram mechanism, which range from a few MeV to a few tens of MeV. We strongly recommend future experimental searches for the $${\Sigma }_{c}^{(*)}\Sigma _{c}^{(*)}$$

Σ

c

(

∗
)

Σ

c

(

∗
)

hexaquark states in the $$\Lambda _c\Lambda _c$$

Λ
c

Λ
c

invariant mass distributions.
Conformal vector fields of Bianchi type-I spacetimes
Authors: Khan Suhail , Bukhari Maria , Alkhaldi Ali H. , Ali Akram
Published: December 2021

This paper aims to investigate Conformal Vector Fields (CVFs) of Bianchi type-I spacetimes. A set of 10-coupled Partial Differential Equations (PDEs) is obtained from the conformal Killing equations. These equations are solved by using direct integration techniques to explore the components of CVFs. Utilizing these components, we get a system of three integrability conditions. Finally, we achieve CVFs along with conformal factors for unique possibilities of unknown metric functions from the solution of these conditions. From our results, it is examined that Bianchi type-I spacetimes admit five or fifteen CVFs for specific choices of metric functions.
Explicit volume formula for a hyperbolic tetrahedron in terms of edge lengths
Authors: Abrosimov Nikolay , Vuong Bao
Published: December 2021

We consider a compact hyperbolic tetrahedron of a general type. It is a convex hull of four points called vertices in the hyperbolic space [Formula: see text]. It can be determined by the set of six edge lengths up to isometry. For further considerations, we use the notion of edge matrix of the tetrahedron formed by hyperbolic cosines of its edge lengths.

We establish necessary and sufficient conditions for the existence of a tetrahedron in [Formula: see text]. Then we find relations between their dihedral angles and edge lengths in the form of a cosine rule. Finally, we obtain exact integral formula expressing the volume of a hyperbolic tetrahedron in terms of the edge lengths. The latter volume formula can be regarded as a new version of classical Sforza’s formula for the volume of a tetrahedron but in terms of the edge matrix instead of the Gram matrix.
A study of alpha-decay using effective liquid drop model
Authors: Sridhara G. R. , Manjunatha H. C. , Sowmya N. , Gupta P. S. Damodara
Published: December 2021

In this paper, we have made an attempt to analyze the alpha-decay half-lives of in the atomic number range [Formula: see text] by considering an effective liquid drop model. The role of pre-formation probability by including iso-spin effect is included during an evaluation of half-lives. We have also compared the studied alpha-decay half-lives with that of semi-empirical formulae such as Viola Seaborg semi-empirical formulae (VSS) [J. Inorg. Nucl. Chem. 28 (1966) 741; Nucl. Phys. A 848 (2010) 279], Royer formulae [J. Phys. G: Nucl. Part. Phys. 26 (2000) 1149; Phys. Rev. C 101 (2020) 034307] and also with that of the available experiments. From this comparison, it can be concluded that the effective liquid drop model produces an alpha-decay half-lives close to the experiments.
A note on the concordance invariants Upsilon and phi
Authors: Wang Shida
Published: December 2021

Dai, Hom, Stoffregen and Truong defined a family of concordance invariants [Formula: see text]. The example of a knot with zero Upsilon invariant but nonzero epsilon invariant previously given by Hom also has nonzero phi invariant. We show there are infinitely many such knots that are linearly independent in the smooth concordance group. In the opposite direction, we build infinite families of linearly independent knots with zero phi invariant but nonzero Upsilon invariant. We also give a recursive formula for the phi invariant of torus knots.
2D and 2.5D Numerical Simulations for Vortex-Induced Vibration (VIV) of a 1.5:1 Rectangular Cylinder
Authors: Yan Bowen , Yuan Yangjin , Li Dalong , Li Ke , Yang Qingshan , Lin Ding , Piccardo Giuseppe
Published: December 2021

The semi-periodic vortex-shedding phenomenon caused by flow separation at the windward corners of a rectangular cylinder would result in significant vortex-induced vibrations (VIVs). Based on the aeroelastic experiment of a rectangular cylinder with side ratio of 1.5:1, 2-dimensional (2D) and 2.5-dimensional (2.5D) numerical simulations of the VIV of a rectangular cylinder were comprehensively validated. The mechanism of VIV of the rectangular cylinder was in detail discussed in terms of vortex-induced forces, aeroelastic response, work analysis, aerodynamic damping ratio and flow visualization. The outcomes showed that the numerical results of aeroelastic displacement in the cross-wind direction and the vortex-shedding procedure around the rectangular cylinder were in general consistence with the experimental results by 2.5D numerical simulation. In both simulations, the phase difference between the lift and displacement response increased with the reduced wind speed and the vortex-induced resonance (VIR) disappeared at the phase difference of approximately 180∘. The work done by lift force shows a close relationship with vibration amplitudes at different reduced wind speeds. In 2.5D simulations, the lift force of the rectangular cylinder under different wind speeds would be affected by the presence of small-scale vortices in the turbulence flow field. Similarly, the phase difference between lift force and displacement response was not a constant with the same upstream wind speed. Aerodynamic damping identified from the VIV was mainly dependent on the reduced wind speed and negative damping ratios were revealed at the lock-in regime, which also greatly influenced the probability density function (PDF) of wind-induced displacement.
Dynamic Instability of Functionally Graded Carbon Nanotubes-Reinforced Composite Joined Conical-Cylindrical Shell
Authors: Uspensky B. , Avramov K. , Sakhno N. , Nikonov O.
Published: December 2021

In this paper, dynamic instability of functionally graded carbon nanotubes (CNTs)-reinforced composite joined conical-cylindrical shell in supersonic flow is analyzed numerically. The higher-order shear deformation theory is applied to describe the stress–strain state of thin-walled structure. The assumed-mode method is used to derive the finite degrees-of-freedom dynamical system, which describes the structure motions. The structure motions are expanded by using the eigenmodes, which are obtained by the Rayleigh–Ritz method. The trial functions, which satisfy the continuity conditions at the cylindrical-cone junction, are used to obtain the eigenmodes.

The properties of free vibrations of thin-walled structure are analyzed numerically. The dynamic instability of the joined conical-cylindrical shell in supersonic flow is analyzed using the characteristic exponents. As follows from the numerical study, the dynamic instability is arisen due to the Hopf bifurcation. The dependences of the supersonic flow critical pressure on the Mach number and the type of CNTs distribution are analyzed numerically.
Poisson algebra structure on the invariants of pairs of matrices of degree three
Authors: Normatov Z. , Turdibaev R.
Published: December 2021

We provide a table of multiplication of the Poisson algebra on the minimal set of generators of the invariants of pairs of matrices of degree three.
Empirical study based on the model of rough fractional stochastic volatility (RFSV)
Authors: Zhang Songyan , Hu Chaoyong
Published: December 2021

To estimate the parameters of the model of option pricing based on the model of rough fractional stochastic volatility (RFSV), we have carried out the empirical analysis during our study on the pricing of SSE 50ETF options in China. First, we have estimated the parameters of option pricing model by adopting the Monte Carlo simulation. Subsequently, we have empirically examined the pricing performance of the RFSV model by adopting the SSE 50ETF option price from January 2019 to December 2020. Our research findings indicate that by leveraging the RFSV model, we are able to attain a more accurate and stable level of option pricing than the conventional Black–Scholes (B-S) model on constant volatility. The errors of option pricing incurred by the B-S model proved to be larger and exhibited higher volatility, revealing the significant impact imposed by stochastic volatility on option pricing.
Eight New Challenges Faced by Global Economy
Authors: Zhang Yuyan
Published: December 2021

Due to COVID-19, the world has experienced the most severe economic recession since the Second World War. Some "unconventional" monetary policies have been enforced in order to stimulate the economy, and their effectiveness is positively regarded by the IMF. However, this paper identifies two negative effects of these measures. Firstly, they exacerbate policy instability; secondly, they will be detrimental to the fundamentals of monetary policies in the long term. In addition, the world economy is also confronted with many challenges, including global inflation expectations, the trends of dollar as a currency, restructuring of global supply chain, volatility of asset prices and commodity prices, and global and regional governance.
Scratching the surface(s): examining the complexity of geological contexts for the Palaeolithic of the Sonar Basin, Madhya Pradesh
Authors: Pardiwalla Yezad
Published: December 2021

The Sonar River Valley is centrally located in Madhya Pradesh, flanked by rich Palaeolithic and fossiliferous localities in the Son and Narmada valleys and has historically been overlooked in favour of the latter rivers, which tend to preserve well-stratified Quaternary formations along varying portions of their length. Here an attempt is made to look at the Sonar Basin through a broader lens, examining the various landforms found in the district of Damoh through which the Sonar flows before joining the Ken. The objective of this paper is threefold: to bring together the geomorphology of the area both in association with and as a result of fluvial action but also as a product of other geomorphic processes; to understand the consequences these processes have for the visibility of the prehistoric archaeological record within the region; and to look at this geoarchaeological relationship in the wider context of some of the major river basins in Madhya Pradesh, notably the Son and Narmada. Secondary sources on geology and geoarchaeology have been integrated with preliminary fieldwork in Districts Damoh and Narsinghpur, and to a smaller extent in Sagar, Chhatarpur and Panna. This work demonstrates the complexity of the South Asian Palaeolithic record that stretches beyond fluvial contexts, in turn helping to spatially expand our understanding of hominin behaviour beyond narrow riverine corridors.
Early Pliocene marine transgression into the lower Colorado River valley, southwestern USA, by re-flooding of a former tidal strait
Authors: Dorsey Rebecca J. , Braga Juan Carlos , Gardner Kevin , McDougall Kristin , O'Connell Brennan
Published: December 2021

Marine straits and seaways are known to host a wide range of sedimentary processes and products, but the role of marine connections in the development of large river systems remains little studied. This study explores a hypothesis that shallow-marine waters flooded the lower Colorado River valley at
c.
5 Ma along a fault-controlled former tidal strait, soon after the river was first integrated into the northern Gulf of California. The upper bioclastic member of the southern Bouse Formation provides a critical test of this hypothesis. The upper bioclastic member contains wave ripple-laminated bioclastic grainstone with minor red mudstone, pebbly grainstone with hummocky cross-stratification (HCS)-like stratification and symmetrical gravelly ripples, and calcareous-matrix conglomerate. Fossils include upward-branching segmented coralline-like red algae with no known modern relatives but confirmed as marine calcareous algae, echinoid spines, barnacles, shallow-marine foraminifers, clams, and serpulid worm tubes. These results provide evidence for deposition in a shallow-marine bay or estuary seaward of the transgressive backstepping Colorado River delta. Tsunamis generated by seismic and meteorological sources likely produced the HCS-like and wave-ripple cross-bedding in poorly-sorted gravelly grainstone. Marine waters inundated a former tidal strait within a fault-bounded tectonic lowland that connected the lower Colorado River to the Gulf of California. Delta backstepping and transgression resulted from a decrease in sediment output due to sediment trapping in upstream basins and relative sea-level rise produced by regional tectonic subsidence.
PBNS
Authors: Bertiche Hugo , Madadi Meysam , Escalera Sergio
Published: December 2021

We present a methodology to automatically obtain Pose Space Deformation (PSD) basis for rigged garments through deep learning. Classical approaches rely on Physically Based Simulations (PBS) to animate clothes. These are general solutions that, given a sufficiently fine-grained discretization of space and time, can achieve highly realistic results. However, they are computationally expensive and any scene modification prompts the need of re-simulation. Linear Blend Skinning (LBS) with PSD offers a lightweight alternative to PBS, though, it needs huge volumes of data to learn proper PSD. We propose using deep learning, formulated as an implicit PBS, to un-supervisedly learn realistic cloth Pose Space Deformations in a constrained scenario: dressed humans. Furthermore, we show it is possible to train these models in an amount of time comparable to a PBS of a few sequences. To the best of our knowledge, we are the first to propose a neural simulator for cloth. While deep-based approaches in the domain are becoming a trend, these are data-hungry models. Moreover, authors often propose complex formulations to better learn wrinkles from PBS data. Supervised learning leads to physically inconsistent predictions that require collision solving to be used. Also, dependency on PBS data limits the scalability of these solutions, while their formulation hinders its applicability and compatibility. By proposing an unsupervised methodology to learn PSD for LBS models (3D animation standard), we overcome both of these drawbacks. Results obtained show cloth-consistency in the animated garments and meaningful pose-dependant folds and wrinkles. Our solution is extremely efficient, handles multiple layers of cloth, allows unsupervised outfit resizing and can be easily applied to any custom 3D avatar.
Deep3DLayout
Authors: Pintore Giovanni , Almansa Eva , Agus Marco , Gobbetti Enrico
Published: December 2021

Recovering the 3D shape of the bounding permanent surfaces of a room from a single image is a key component of indoor reconstruction pipelines. In this article, we introduce a novel deep learning technique capable to produce, at interactive rates, a tessellated bounding 3D surface from a single 360° image. Differently from prior solutions, we fully address the problem in 3D, significantly expanding the reconstruction space of prior solutions. A graph convolutional network directly infers the room structure as a 3D mesh by progressively deforming a graph-encoded tessellated sphere mapped to the spherical panorama, leveraging perceptual features extracted from the input image. Important 3D properties of indoor environments are exploited in our design. In particular, gravity-aligned features are actively incorporated in the graph in a projection layer that exploits the recent concept of multi head self-attention, and specialized losses guide towards plausible solutions even in presence of massive clutter and occlusions. Extensive experiments demonstrate that our approach outperforms current state of the art methods in terms of accuracy and capability to reconstruct more complex environments.
Cascaded Sobol' sampling
Authors: Paulin Loïs , Coeurjolly David , Iehl Jean-Claude , Bonneel Nicolas , Keller Alexander , Ostromoukhov Victor
Published: December 2021

Rendering quality is largely influenced by the samplers used in Monte Carlo integration. Important factors include sample uniformity (e.g., low discrepancy) in the high-dimensional integration domain, sample uniformity in lower-dimensional projections, and lack of dominant structures that could result in aliasing artifacts. A widely used and successful construction is the Sobol' sequence that guarantees good high-dimensional uniformity and consequently results in faster convergence of quasi-Monte Carlo integration. We show that this sequence exhibits low uniformity and dominant structures in low-dimensional projections. These structures impair quality in the context of rendering, as they precisely occur in the 2-dimensional projections used for sampling light sources, reflectance functions, or the camera lens or sensor. We propose a new cascaded construction, which, despite dropping the sequential aspect of Sobol' samples, produces point sets exhibiting provably perfect dyadic partitioning (and therefore, excellent uniformity) in consecutive 2-dimensional projections, while preserving good high-dimensional uniformity. By optimizing the initialization parameters and performing Owen scrambling at finer levels of binary representations, we further improve over Sobol's integration convergence rate. Our method does not incur any overhead as compared to the generation of the Sobol' sequence, is compatible with Owen scrambling and can be used in rendering applications.
Continuous aerial path planning for 3D urban scene reconstruction
Authors: Zhang Han , Yao Yucong , Xie Ke , Fu Chi-Wing , Zhang Hao , Huang Hui
Published: December 2021

We introduce the first
path-oriented
drone trajectory planning algorithm, which performs
continuous
(i.e.,
dense
) image acquisition along an aerial path and explicitly factors
path quality
into an optimization along with scene reconstruction quality. Specifically, our method takes as input a rough 3D scene proxy and produces a drone trajectory and image capturing setup, which efficiently yields a high-quality reconstruction of the 3D scene based on three optimization objectives: one to maximize the
amount of 3D scene information
that can be acquired along the entirety of the trajectory, another to optimize the scene capturing
efficiency
by maximizing the scene information that can be acquired per unit length along the aerial path, and the last one to minimize the total
turning angles
along the aerial path, so as to reduce the number of sharp turns. Our search scheme is based on the rapidly-exploring random tree framework, resulting in a final trajectory as a single path through the search tree. Unlike state-of-the-art works, our joint optimization for view selection and path planning is performed in a
single step.
We comprehensively evaluate our method not only on benchmark virtual datasets as in existing works but also on several large-scale real urban scenes. We demonstrate that the continuous paths optimized by our method can effectively reduce onsite acquisition cost using drones, while achieving high-fidelity 3D reconstruction, compared to existing planning methods and oblique photography, a mature and popular industry solution.
Project starline
Authors: Lawrence Jason , Goldman Danb , Achar Supreeth , Blascovich Gregory Major , Desloge Joseph G. , Fortes Tommy , Gomez Eric M. , Häberling Sascha , Hoppe Hugues , Huibers Andy , Knaus Claude , Kuschak Brian , Martin-Brualla Ricardo , Nover Harris , Russell Andrew Ian , Seitz Steven M. , Tong Kevin
Published: December 2021

We present a real-time bidirectional communication system that lets two people, separated by distance, experience a face-to-face conversation as if they were copresent. It is the first telepresence system that is demonstrably better than 2D videoconferencing, as measured using participant ratings (e.g., presence, attentiveness, reaction-gauging, engagement), meeting recall, and observed nonverbal behaviors (e.g., head nods, eyebrow movements). This milestone is reached by maximizing audiovisual fidelity and the sense of copresence in all design elements, including physical layout, lighting, face tracking, multi-view capture, microphone array, multi-stream compression, loudspeaker output, and lenticular display. Our system achieves key 3D audiovisual cues (stereopsis, motion parallax, and spatialized audio) and enables the full range of communication cues (eye contact, hand gestures, and body language), yet does not require special glasses or body-worn microphones/headphones. The system consists of a head-tracked autostereoscopic display, high-resolution 3D capture and rendering subsystems, and network transmission using compressed color and depth video streams. Other contributions include a novel image-based geometry fusion algorithm, free-space dereverberation, and talker localization.
Fast and versatile fluid-solid coupling for turbulent flow simulation
Authors: Lyu Chaoyang , Li Wei , Desbrun Mathieu , Liu Xiaopei
Published: December 2021

The intricate motions and complex vortical structures generated by the interaction between fluids and solids are visually fascinating. However, reproducing such a two-way coupling between thin objects and turbulent fluids numerically is notoriously challenging and computationally costly: existing approaches such as cut-cell or immersed-boundary methods have difficulty achieving physical accuracy, or even visual plausibility, of simulations involving fast-evolving flows with immersed objects of arbitrary shapes. In this paper, we propose an efficient and versatile approach for simulating two-way fluid-solid coupling within the kinetic (lattice-Boltzmann) fluid simulation framework, valid for both laminar and highly turbulent flows, and for both thick and thin objects. We introduce a novel hybrid approach to fluid-solid coupling which systematically involves a mesoscopic double-sided bounce-back scheme followed by a cut-cell velocity correction for a more robust and plausible treatment of turbulent flows near moving (thin) solids, preventing flow penetration and reducing boundary artifacts significantly. Coupled with an efficient approximation to simplify geometric computations, the whole boundary treatment method preserves the inherent massively parallel computational nature of the kinetic method. Moreover, we propose simple GPU optimizations of the core LBM algorithm which achieve an even higher computational efficiency than the state-of-the-art kinetic fluid solvers in graphics. We demonstrate the accuracy and efficacy of our two-way coupling through various challenging simulations involving a variety of rigid body solids and fluids at both high and low Reynolds numbers. Finally, comparisons to existing methods on benchmark data and real experiments further highlight the superiority of our method.
I♥LA
Authors: Li Yong , Kamil Shoaib , Jacobson Alec , Gingold Yotam
Published: December 2021

Communicating linear algebra in written form is challenging: mathematicians must choose between writing in languages that produce well-formatted but semantically-underdefined representations such as LaTeX; or languages with well-defined semantics but notation unlike conventional math, such as C++/Eigen. In both cases, the underlying linear algebra is obfuscated by the requirements of esoteric language syntax (as in LaTeX) or awkward APIs due to language semantics (as in C++). The gap between representations results in communication challenges, including underspecified and irrepro-ducible research results, difficulty teaching math concepts underlying complex numerical code, as well as repeated, redundant, and error-prone translations from communicated linear algebra to executable code. We introduce I♥LA, a language with syntax designed to closely mimic conventionally-written linear algebra, while still ensuring an unambiguous, compilable interpretation. Inspired by Markdown, a language for writing naturally-structured plain text files that translate into valid HTML, I♥LA allows users to write linear algebra in text form and compile the same source into LaTeX, C++/Eigen, Python/NumPy/SciPy, and MATLAB, with easy extension to further math programming environments. We outline the principles of our language design and highlight design decisions that balance between readability and precise semantics, and demonstrate through case studies the ability for I♥LA to bridge the semantic gap between conventionally-written linear algebra and unambiguous interpretation in math programming environments.
Generalized deployable elastic geodesic grids
Authors: Pillwein Stefan , Musialski Przemyslaw
Published: December 2021

Given a designer created free-form surface in 3d space, our method computes a grid composed of elastic elements which are completely planar and straight. Only by fixing the ends of the planar elements to appropriate locations, the 2d grid bends and approximates the given 3d surface. Our method is based purely on the notions from differential geometry of curves and surfaces and avoids any physical simulations. In particular, we introduce a well-defined elastic grid energy functional that allows identifying networks of curves that minimize the bending energy and at the same time nestle to the provided input surface well. Further, we generalize the concept of such grids to cases where the surface boundary does not need to be convex, which allows for the creation of sophisticated and visually pleasing shapes. The algorithm finally ensures that the 2d grid is perfectly planar, making the resulting gridshells inexpensive, easy to fabricate, transport, assemble, and finally also to deploy. Additionally, since the whole structure is pre-strained, it also comes with load-bearing capabilities. We evaluate our method using physical simulation and we also provide a full fabrication pipeline for desktop-size models and present multiple examples of surfaces with elliptic and hyperbolic curvature regions. Our method is meant as a tool for quick prototyping for designers, architects, and engineers since it is very fast and results can be obtained in a matter of seconds.
Repulsive surfaces
Authors: Yu Chris , Brakensiek Caleb , Schumacher Henrik , Crane Keenan
Published: December 2021

Functionals that penalize bending or stretching of a surface play a key role in geometric and scientific computing, but to date have ignored a very basic requirement: in many situations, surfaces must not pass through themselves or each other. This paper develops a numerical framework for optimization of surface geometry while avoiding (self-)collision. The starting point is the
tangent-point energy
, which effectively pushes apart pairs of points that are close in space but distant along the surface. We develop a discretization of this energy for triangle meshes, and introduce a novel acceleration scheme based on a fractional Sobolev inner product. In contrast to similar schemes developed for curves, we avoid the complexity of building a multiresolution mesh hierarchy by decomposing our preconditioner into two ordinary Poisson equations, plus forward application of a fractional differential operator. We further accelerate this scheme via hierarchical approximation, and describe how to incorporate a variety of constraints (on area, volume,
etc.
). Finally, we explore how this machinery might be applied to problems in mathematical visualization, geometric modeling, and geometry processing.
Computing sparse cones with bounded distortion for conformal parameterizations
Authors: Fang Qing , Ouyang Wenqing , Li Mo , Liu Ligang , Fu Xiao-Ming
Published: December 2021

We propose a novel method to generate sparse cone singularities with bounded distortion constraints for conformal parameterizations. It is formulated as minimizing the
ℓ
0
-norm of Gaussian curvature of vertices with hard constraints of bounding the distortion that is measured by the
ℓ
2
-norm of the log conformal factor. We use the reweighted
ℓ
1
-norm to approximate the
ℓ
0
-norm and solve each convex weighted
ℓ
1
minimization subproblem by the Douglas-Rachford (DR) splitting scheme. To quickly generate sparse cones, we modify DR splitting by weighting the
ℓ
2
-norm of the proximal mapping to force the small Gaussian curvature to quickly approach zero. Accordingly, compared with the conventional DR splitting, the modified method performs one to two orders of magnitude faster. Besides, we perform variable substitution of log conformal factors to simplify the computation process for acceleration. Our algorithm is able to bound distortion to compute sparse cone singularities, so that the resulting conformal parameterizations achieve a favorable tradeoff between the area distortion and the number of cones. We demonstrate its effectiveness and feasibility on a large number of models.
Weatherscapes
Authors: Herrera Jorge Alejandro Amador , Hädrich Torsten , Pałubicki Wojtek , Banuti Daniel T. , Pirk Sören , Michels Dominik L.
Published: December 2021

Due to the complex interplay of various meteorological phenomena, simulating weather is a challenging and open research problem. In this contribution, we propose a novel physics-based model that enables simulating weather at interactive rates. By considering atmosphere and pedosphere we can define the hydrologic cycle - and consequently weather - in unprecedented detail. Specifically, our model captures different warm and cold clouds, such as mammatus, hole-punch, multi-layer, and cumulonimbus clouds as well as their dynamic transitions. We also model different precipitation types, such as rain, snow, and graupel by introducing a comprehensive microphysics scheme. The Wegener-Bergeron-Findeisen process is incorporated into our Kessler-type microphysics formulation covering ice crystal growth occurring in mixed-phase clouds. Moreover, we model the water run-off from the ground surface, the infiltration into the soil, and its subsequent evaporation back to the atmosphere. We account for daily temperature changes, as well as heat transfer between pedosphere and atmosphere leading to a complex feedback loop. Our framework enables us to interactively explore various complex weather phenomena. Our results are assessed visually and validated by simulating weatherscapes for various setups covering different precipitation events and environments, by showcasing the hydrologic cycle, and by reproducing common effects such as Foehn winds. We also provide quantitative evaluations creating high-precipitation cumulonimbus clouds by prescribing atmospheric conditions based on infrared satellite observations. With our model we can generate dynamic 3D scenes of weatherscapes with high visual fidelity and even nowcast real weather conditions as simulations by streaming weather data into our framework.
Multi-class inverted stippling
Authors: Schulz Christoph , Kwan Kin Chung , Becher Michael , Baumgartner Daniel , Reina Guido , Deussen Oliver , Weiskopf Daniel
Published: December 2021

We introduce
inverted stippling
, a method to mimic an inversion technique used by artists when performing stippling. To this end, we extend Linde-Buzo-Gray (LBG) stippling to multi-class LBG (MLBG) stippling with multiple layers. MLBG stippling couples the layers stochastically to optimize for per-layer and overall blue-noise properties. We propose a stipple-based filling method to generate solid color backgrounds for inverting areas. Our experiments demonstrate the effectiveness of MLBG in terms of reducing overlapping and intensity accuracy. In addition, we showcase MLBG with color stippling and dynamic multi-class blue-noise sampling, which is possible due to its support for temporal coherence.
FrictionalMonolith
Authors: Takahashi Tetsuya , Batty Christopher
Published: December 2021

We propose
FrictionalMonolith
, a monolithic pressure-friction-contact solver for more accurately, robustly, and efficiently simulating two-way interactions of rigid bodies with continuum granular materials or inviscid liquids. By carefully formulating the components of such systems within a single unified minimization problem, our solver can simultaneously handle unilateral incompressibility and implicit integration of friction for the interior of the continuum, frictional contact resolution among the rigid bodies, and mutual force exchanges between the continuum and rigid bodies. Our monolithic approach eliminates various problematic artifacts in existing weakly coupled approaches, including loss of volume in the continuum material, artificial drift and slip of the continuum at solid boundaries, interpenetrations of rigid bodies, and simulation instabilities. To efficiently handle this challenging monolithic minimization problem, we present a customized solver for the resulting quadratically constrained quadratic program that combines elements of staggered projections, augmented Lagrangian methods, inexact projected Newton, and active-set methods. We demonstrate the critical importance of a unified treatment and the effectiveness of our proposed solver in a range of practical scenarios.
Beyond mie theory
Authors: Guo Yu , Jarabo Adrian , Zhao Shuang
Published: December 2021

Light scattering in participating media and translucent materials is typically modeled using the radiative transfer theory. Under the assumption of independent scattering between particles, it utilizes several bulk scattering parameters to statistically characterize light-matter interactions at the macroscale. To calculate these parameters based on microscale material properties, the Lorenz-Mie theory has been considered the gold standard. In this paper, we present a generalized framework capable of systematically and rigorously computing bulk scattering parameters beyond the far-field assumption of Lorenz-Mie theory. Our technique accounts for microscale wave-optics effects such as diffraction and interference as well as interactions between nearby particles. Our framework is general, can be plugged in any renderer supporting Lorenz-Mie scattering, and allows arbitrary packing rates and particles correlation; we demonstrate this generality by computing bulk scattering parameters for a wide range of materials, including anisotropic and correlated media.
Modeling clothing as a separate layer for an animatable human avatar
Authors: Xiang Donglai , Prada Fabian , Bagautdinov Timur , Xu Weipeng , Dong Yuan , Wen He , Hodgins Jessica , Wu Chenglei
Published: December 2021

We have recently seen great progress in building photorealistic animatable full-body codec avatars, but generating high-fidelity animation of clothing is still difficult. To address these difficulties, we propose a method to build an animatable clothed body avatar with an explicit representation of the clothing on the upper body from multi-view captured videos. We use a two-layer mesh representation to register each 3D scan separately with the body and clothing templates. In order to improve the photometric correspondence across different frames, texture alignment is then performed through inverse rendering of the clothing geometry and texture predicted by a variational autoencoder. We then train a new two-layer codec avatar with separate modeling of the upper clothing and the inner body layer. To learn the interaction between the body dynamics and clothing states, we use a temporal convolution network to predict the clothing latent code based on a sequence of input skeletal poses. We show photorealistic animation output for three different actors, and demonstrate the advantage of our clothed-body avatars over the single-layer avatars used in previous work. We also show the benefit of an explicit clothing model that allows the clothing texture to be edited in the animation output.
Layered neural atlases for consistent video editing
Authors: Kasten Yoni , Ofri Dolev , Wang Oliver , Dekel Tali
Published: December 2021

We present a method that decomposes, and "unwraps", an input video into a set of
layered 2D atlases
, each providing a
unified representation
of the appearance of an object (or background) over the video. For each pixel in the video, our method estimates its corresponding 2D coordinate in each of the atlases, giving us a consistent parameterization of the video, along with an associated alpha (opacity) value. Importantly, we design our atlases to be interpretable and semantic, which facilitates easy and intuitive editing in the atlas domain, with minimal manual work required. Edits applied to
a single 2D atlas
(or input video frame) are automatically and consistently mapped back to the original video frames, while preserving occlusions, deformation, and other complex scene effects such as shadows and reflections. Our method employs a coordinate-based Multilayer Perceptron (MLP) representation for mappings, atlases, and alphas, which are jointly optimized on a per-video basis, using a combination of video reconstruction and regularization losses. By operating purely in 2D, our method does not require any prior 3D knowledge about scene geometry or camera poses, and can handle complex dynamic real world videos. We demonstrate various video editing applications, including texture mapping, video style transfer, image-to-video texture transfer, and segmentation/labeling propagation, all automatically produced by editing a single 2D atlas image.
Modeling flower pigmentation patterns
Authors: Ringham Lee , Owens Andrew , Cieslak Mikolaj , Harder Lawrence D. , Prusinkiewicz Przemyslaw
Published: December 2021

Although many simulation models of natural phenomena have been developed to date, little attention was given to a major contributor to the beauty of nature: the colorful patterns of flowers. We survey typical patterns and propose methods for simulating them inspired by the current understanding of the biology of floral patterning. The patterns are generated directly on geometric models of flowers, using different combinations of key mathematical models of morphogenesis: vascular patterning, positional information, reaction-diffusion, and random pattern generation. The integration of these models makes it possible to capture a wide range of the flower pigmentation patterns observed in nature.
Optimizing contact-based assemblies
Authors: Tozoni Davi Colli , Zhou Yunfan , Zorin Denis
Published: December 2021

Modern fabrication methods have greatly simplified manufacturing of complex free-form shapes at an affordable cost, and opened up new possibilities for improving functionality and customization through automatic optimization, shape optimization in particular. However, most existing shape optimization methods focus on single parts. In this work, we focus on supporting shape optimization for assemblies, more specifically, assemblies that are held together by contact and friction. Examples of which include furniture joints, construction set assemblies, certain types of prosthetic devices and many other. To enable this optimization, we present a framework supporting robust and accurate optimization of a number of important functionals, while enforcing constraints essential for assembly functionality: weight, stress, difficulty of putting the assembly together, and how reliably it stays together. Our framework is based on smoothed formulation of elasticity equations with contact, analytically derived shape derivatives, and robust remeshing to enable large changes of shape, and at the same time, maintain accuracy. We demonstrate the improvements it can achieve for a number of computational and experimental examples.
Binaural audio generation via multi-task learning
Authors: Li Sijia , Liu Shiguang , Manocha Dinesh
Published: December 2021

We present a learning-based approach for generating binaural audio from mono audio using multi-task learning. Our formulation leverages additional information from two related tasks: the binaural audio generation task and the flipped audio classification task. Our learning model extracts spatialization features from the visual and audio input, predicts the left and right audio channels, and judges whether the left and right channels are flipped. First, we extract visual features using ResNet from the video frames. Next, we perform binaural audio generation and flipped audio classification using separate subnetworks based on visual features. Our learning method optimizes the overall loss based on the weighted sum of the losses of the two tasks. We train and evaluate our model on the FAIR-Play dataset and the YouTube-ASMR dataset. We perform quantitative and qualitative evaluations to demonstrate the benefits of our approach over prior techniques.
Convex polyhedral meshing for robust solid modeling
Authors: Diazzi Lorenzo , Attene Marco
Published: December 2021

We introduce a new technique to create a mesh of convex polyhedra representing the interior volume of a triangulated input surface. Our approach is particularly tolerant to defects in the input, which is allowed to self-intersect, to be non-manifold, disconnected, and to contain surface holes and gaps. We guarantee that the input surface is exactly represented as the union of polygonal facets of the output volume mesh. Thanks to our algorithm, traditionally
difficult
solid modeling operations such as mesh booleans and Minkowski sums become surprisingly robust and easy to implement, even if the input has defects. Our technique leverages on the recent concept of indirect geometric predicate to provide an unprecedented combination of guaranteed robustness and speed, thus enabling the practical implementation of robust though flexible solid modeling systems. We have extensively tested our method on all the 10000 models of the Thingi10k dataset, and concluded that no existing method provides comparable robustness, precision and performances.
Mitochondrial Dysfunction and Diabetic Nephropathy: Nontraditional Therapeutic Opportunities
Authors: Zhang Ping Na , Zhou Meng Qi , Guo Jing , Zheng Hui Juan , Tang Jingyi , Zhang Chao , Liu Yu Ning , Liu Wei Jing , Wang Yao Xian
Published: December 2021

Diabetic nephropathy (DN) is a progressive microvascular diabetic complication. Growing evidence shows that persistent mitochondrial dysfunction contributes to the progression of renal diseases, including DN, as it alters mitochondrial homeostasis and, in turn, affects normal kidney function. Pharmacological regulation of mitochondrial networking is a promising therapeutic strategy for preventing and restoring renal function in DN. In this review, we have surveyed recent advances in elucidating the mitochondrial networking and signaling pathways in physiological and pathological contexts. Additionally, we have considered the contributions of nontraditional therapy that ameliorate mitochondrial dysfunction and discussed their molecular mechanism, highlighting the potential value of nontraditional therapies, such as herbal medicine and lifestyle interventions, in therapeutic interventions for DN. The generation of new insights using mitochondrial networking will facilitate further investigations on nontraditional therapies for DN.
Ileocaecal Tuberculosis Presenting with Massive Hematochezia: A Rare Clinical Manifestation
Authors: Mehta Neha , Paudyal Man Bahadur , Shah Sangam , Chamlagain Rajan , Shrestha Moon , Mehta Ashish , Bhattarai Prabin
Published: December 2021

Abdominal pain, diarrhea, weight loss, anorexia, and fever are common symptoms of intestinal tuberculosis, while bleeding from the lumen, intestinal obstruction, perforation, and fistula formation are uncommon presentations in ileocaecal tuberculosis. Here, we present a case of a 33-year-old male with intestinal tuberculosis who initially presented with massive bleeding per rectum.