Deep4D: A Compact Generative Representation for Volumetric Video

This paper introduces Deep4D a compact generative representation of shape and appearance from captured 4D volumetric video sequences of people. 4D volumetric video achieves highly realistic reproduction, replay and free-viewpoint rendering of actor performance from multiple view video acquisition systems. A deep generative network is trained on 4D video sequences of an actor performing multiple motions to learn a generative model of the dynamic shape and appearance. We demonstrate the proposed generative model can provide a compact encoded representation capable of high-quality synthesis of 4D volumetric video with two orders of magnitude compression. A variational encoder-decoder network is employed to learn an encoded latent space that maps from 3D skeletal pose to 4D shape and appearance. This enables high-quality 4D volumetric video synthesis to be driven by skeletal motion, including skeletal motion capture data. This encoded latent space supports the representation of multiple sequences with dynamic interpolation to transition between motions. Therefore we introduce Deep4D motion graphs, a direct application of the proposed generative representation. Deep4D motion graphs allow real-tiome interactive character animation whilst preserving the plausible realism of movement and appearance from the captured volumetric video. Deep4D motion graphs implicitly combine multiple captured motions from a unified representation for character animation from volumetric video, allowing novel character movements to be generated with dynamic shape and appearance detail.

Geometry Monitoring of Rotating Parts of Power Unit with an Adapted Doppler Preprocessor

Current work is devoted to the development of a device for monitoring the dynamic shape of a power unit. The work is based on the FMCW method. The light source uses a low-coherence semiconductor laser diode. Signal processing is performed on an adapted Doppler processor. The paper describes the methods, hardware and signal processing algorithms.

DETERMINATION OF THE COEFFICIENT OF THE DYNAMIC SHAPE OF DUST PARTICLES RELEASED IN THE AREA OF GRINDING MACHINES

При проведении работ по заточке твердосплавных инструментов абразивными кругами на универсальных заточных станках образуется значительное количество пылевых частиц. Часть пылевых частиц, в зависимости от размеров, находится во взвешенном состоянии. Длительное воздействие пылевых аэрозолей на организм рабочих может привезти к развитию большого количества профессиональных заболеваний дыхательных путей. Установлено, что на характер движения пылевых частиц в рабочей зоне и скорость их осаждения влияет такой параметр, как форма пылевой частицы. Материал для исследования и расчета был собран на предприятии ООО «Русский инструмент», которое расположено в пгт. Северный, Белгородского района. Отбор проб производился в разных зонах заточного участка. На основе имеющихся проб пылевых частиц, на базе лаборатории БГТУ им. В. Г. Шухова, были получены результаты электронной микроскопии. Целью данной работы является определение коэффициента формы пылевых частиц, с использованием существующих методик определения данного коэффициента. Полученные результаты позволяют дополнить исходные данные для разработки математической модели процессов течения пылевых частиц вблизи местного отсоса и последующего компьютерного моделирования течений пылевых аэрозолей в кожухе-пылеуловителе. When working on sharpening carbide tools with abrasive wheels on universal grinding machines, a significant amount of dust particles is formed. A certain part of the dust particles, depending on the size, is suspended. Prolonged exposure to dust aerosols on the body of machine turners can lead to the development of a large number of occupational diseases of the respiratory tract. It is established that in the working area, the nature of the movement of dust particles, as well as the rate of their deposition, is affected by such a parameter as the shape of the dust particle. The material for the study, calculation and subsequent computer simulation of the dust aerosol flows in the dust collector casing was collected at the OOO Russian Tool, which is located in the village Severny, Belgorod district. The samples were taken in different zones of the grinding area. Based on the available samples of dust particles, the results of electron microscopy were obtained at the laboratory of BSTU named after V. G. Shukhov. The purpose of this work is to describe the results obtained and determine the shape coefficient of dust particles, using existing methods for determining this coefficient. The material of the work allows us to supplement the initial data for the development of a mathematical model of the processes of the flow of dust particles near the local suction.

Models of Shear-Induced Platelet Activation and Numerical Implementation with Computational Fluid Dynamics Approaches

Shear-induced platelet activation is one of the critical outcomes when blood is exposed to elevated shear stress. Excessively activated platelets in the circulation can lead to thrombus formation and platelet consumption, resulting in serious adverse events such as thromboembolism and bleeding. While experimental observations reveal that it is related to the shear stress level and exposure time, the underlying mechanism of shear-induced platelet activation is not fully understood. Various models have been proposed to relate shear stress levels to platelet activation, yet most are modified from the empirically calibrated power-law model. Newly developed multiscale platelet models are tested as a promising approach to capture a single platelet's dynamic shape during activation, but it would be computationally expensive to employ it for a large-scale analysis. This paper summarizes the current numerical models used to study the shear-induced platelet activation and their computational applications in the risk assessment of a particular flow pattern and clot formation prediction.

A novel p-harmonic descent approach applied to fluid dynamic shape optimization

We introduce a novel method for the implementation of shape optimization for non-parameterized shapes in fluid dynamics applications, where we propose to use the shape derivative to determine deformation fields with the help of the $$p-$$ p - Laplacian for $$p > 2$$ p > 2 . This approach is closely related to the computation of steepest descent directions of the shape functional in the $$W^{1,\infty }-$$ W 1 , ∞ - topology and refers to the recent publication Deckelnick et al. (A novel $$W^{1,\infty}$$ W 1 , ∞ approach to shape optimisation with Lipschitz domains, 2021), where this idea is proposed. Our approach is demonstrated for shape optimization related to drag-minimal free floating bodies. The method is validated against existing approaches with respect to convergence of the optimization algorithm, the obtained shape, and regarding the quality of the computational grid after large deformations. Our numerical results strongly indicate that shape optimization related to the $$W^{1,\infty }$$ W 1 , ∞ -topology—though numerically more demanding—seems to be superior over the classical approaches invoking Hilbert space methods, concerning the convergence, the obtained shapes and the mesh quality after large deformations, in particular when the optimal shape features sharp corners.