102 research outputs found
DSM-Net: Disentangled Structured Mesh Net for Controllable Generation of Fine Geometry
3D shape generation is a fundamental operation in computer graphics. While
significant progress has been made, especially with recent deep generative
models, it remains a challenge to synthesize high-quality geometric shapes with
rich detail and complex structure, in a controllable manner. To tackle this, we
introduce DSM-Net, a deep neural network that learns a disentangled structured
mesh representation for 3D shapes, where two key aspects of shapes, geometry
and structure, are encoded in a synergistic manner to ensure plausibility of
the generated shapes, while also being disentangled as much as possible. This
supports a range of novel shape generation applications with intuitive control,
such as interpolation of structure (geometry) while keeping geometry
(structure) unchanged. To achieve this, we simultaneously learn structure and
geometry through variational autoencoders (VAEs) in a hierarchical manner for
both, with bijective mappings at each level. In this manner we effectively
encode geometry and structure in separate latent spaces, while ensuring their
compatibility: the structure is used to guide the geometry and vice versa. At
the leaf level, the part geometry is represented using a conditional part VAE,
to encode high-quality geometric details, guided by the structure context as
the condition. Our method not only supports controllable generation
applications, but also produces high-quality synthesized shapes, outperforming
state-of-the-art methods
GIMO: Gaze-Informed Human Motion Prediction in Context
Predicting human motion is critical for assistive robots and AR/VR
applications, where the interaction with humans needs to be safe and
comfortable. Meanwhile, an accurate prediction depends on understanding both
the scene context and human intentions. Even though many works study
scene-aware human motion prediction, the latter is largely underexplored due to
the lack of ego-centric views that disclose human intent and the limited
diversity in motion and scenes. To reduce the gap, we propose a large-scale
human motion dataset that delivers high-quality body pose sequences, scene
scans, as well as ego-centric views with eye gaze that serves as a surrogate
for inferring human intent. By employing inertial sensors for motion capture,
our data collection is not tied to specific scenes, which further boosts the
motion dynamics observed from our subjects. We perform an extensive study of
the benefits of leveraging eye gaze for ego-centric human motion prediction
with various state-of-the-art architectures. Moreover, to realize the full
potential of gaze, we propose a novel network architecture that enables
bidirectional communication between the gaze and motion branches. Our network
achieves the top performance in human motion prediction on the proposed
dataset, thanks to the intent information from the gaze and the denoised gaze
feature modulated by the motion. The proposed dataset and our network
implementation will be publicly available
COPILOT: Human Collision Prediction and Localization from Multi-view Egocentric Videos
To produce safe human motions, assistive wearable exoskeletons must be
equipped with a perception system that enables anticipating potential
collisions from egocentric observations. However, previous approaches to
exoskeleton perception greatly simplify the problem to specific types of
environments, limiting their scalability. In this paper, we propose the
challenging and novel problem of predicting human-scene collisions for diverse
environments from multi-view egocentric RGB videos captured from an
exoskeleton. By classifying which body joints will collide with the environment
and predicting a collision region heatmap that localizes potential collisions
in the environment, we aim to develop an exoskeleton perception system that
generalizes to complex real-world scenes and provides actionable outputs for
downstream control. We propose COPILOT, a video transformer-based model that
performs both collision prediction and localization simultaneously, leveraging
multi-view video inputs via a proposed joint space-time-viewpoint attention
operation. To train and evaluate the model, we build a synthetic data
generation framework to simulate virtual humans moving in photo-realistic 3D
environments. This framework is then used to establish a dataset consisting of
8.6M egocentric RGBD frames to enable future work on the problem. Extensive
experiments suggest that our model achieves promising performance and
generalizes to unseen scenes as well as real world. We apply COPILOT to a
downstream collision avoidance task, and successfully reduce collision cases by
29% on unseen scenes using a simple closed-loop control algorithm.Comment: 8 pages, 6 figure
DSG-Net: Learning disentangled structure and geometry for 3D shape generation
3D shape generation is a fundamental operation in computer graphics. While significant progress has been made, especially with recent deep generative models, it remains a challenge to synthesize high-quality shapes with rich geometric details and complex structures, in a controllable manner. To tackle this, we introduce DSG-Net, a deep neural network that learns a disentangled structured & geometric mesh representation for 3D shapes, where two key aspects of shapes, geometry and structure, are encoded in a synergistic manner to ensure plausibility of the generated shapes, while also being disentangled as much as possible. This supports a range of novel shape generation applications with disentangled control, such as interpolation of structure (geometry) while keeping geometry (structure) unchanged. To achieve this, we simultaneously learn structure and geometry through variational autoencoders (VAEs) in a hierarchical manner for both, with bijective mappings at each level. In this manner, we effectively encode geometry and structure in separate latent spaces, while ensuring their compatibility: the structure is used to guide the geometry and vice versa. At the leaf level, the part geometry is represented using a conditional part VAE, to encode high-quality geometric details, guided by the structure context as the condition. Our method not only supports controllable generation applications, but also produces high-quality synthesized shapes, outperforming state-of-the-art methods
A Large Portal Vein: A Rare Finding of Recent Portal Vein Thrombosis
Acute portal vein thrombosis (PVT) is rarely encountered by clinicians. The most common manifestation of acute PVT is sudden onset of abdominal pain. A computed tomography scan without contrast often shows a high-density material in the portal vein. After injection of contrast agents, absence of luminal enhancement and enlargement of the obstructed portal vein are shown. In this case report, we demonstrated a rare computed tomography finding in which the diameter of the main portal vein was enormously distended to 3-fold that of the aorta in a patient with recent PVT. Despite thrombolysis and anticoagulation were immediately given, portal venous recanalization was not achieved in the patient. After 5 years, variceal bleeding and ascites occurred and liver function had persistently deteriorated. Finally, he died of progressive liver failure. Considering this case, we suggest that an early decision for invasive interventional treatment might be necessary to both increase the rate of portal venous recanalization and improve prognosis, as anticoagulation and thrombolysis therapy failed to recanalize recent PVT
Haisor: Human-aware indoor scene optimization via deep reinforcement learning
3D scene synthesis facilitates and benefits many real-world applications. Most scene generators focus on making indoor scenes plausible via learning from training data and leveraging extra constraints such as adjacency and symmetry. Although the generated 3D scenes are mostly plausible with visually realistic layouts, they can be functionally unsuitable for human users to navigate and interact with furniture. Our key observation is that human activity plays a critical role and sufficient free space is essential for human-scene interactions. This is exactly where many existing synthesized scenes fail—the seemingly correct layouts are often not fit for living. To tackle this, we present a human-aware optimization framework Haisor for 3D indoor scene arrangement via reinforcement learning, which aims to find an action sequence to optimize the indoor scene layout automatically. Based on the hierarchical scene graph representation, an optimal action sequence is predicted and performed via Deep Q-Learning with Monte Carlo Tree Search (MCTS), where MCTS is our key feature to search for the optimal solution in long-term sequences and large action space. Multiple human-aware rewards are designed as our core criteria of human-scene interaction, aiming to identify the next smart action by leveraging powerful reinforcement learning. Our framework is optimized end-to-end by giving the indoor scenes with part-level furniture layout including part mobility information. Furthermore, our methodology is extensible and allows utilizing different reward designs to achieve personalized indoor scene synthesis. Extensive experiments demonstrate that our approach optimizes the layout of 3D indoor scenes in a human-aware manner, which is more realistic and plausible than original state-of-the-art generator results, and our approach produces superior smart actions, outperforming alternative baselines
MicroRNA Let-7f Inhibits Tumor Invasion and Metastasis by Targeting MYH9 in Human Gastric Cancer
BACKGROUND: MicroRNAs (miRNAs) are important regulators that play key roles in tumorigenesis and tumor progression. A previous report has shown that let-7 family members can act as tumor suppressors in many cancers. Through miRNA array, we found that let-7f was downregulated in the highly metastatic potential gastric cancer cell lines GC9811-P and SGC7901-M, when compared with their parental cell lines, GC9811 and SGC7901-NM; however, the mechanism was not clear. In this study, we investigate whether let-7f acts as a tumor suppressor to inhibit invasion and metastasis in gastric cancers. METHODOLOGY/PRINCIPAL: Real-time PCR showed decreased levels of let-7f expression in metastatic gastric cancer tissues and cell lines that are potentially highly metastatic. Cell invasion and migration were significantly impaired in GC9811-P and SGC7901-M cell lines after transfection with let-7f-mimics. Nude mice with xenograft models of gastric cancer confirmed that let-7f could inhibit gastric cancer metastasis in vivo after transfection by the lentivirus pGCsil-GFP- let-7f. Luciferase reporter assays demonstrated that let-7f directly binds to the 3'UTR of MYH9, which codes for myosin IIA, and real-time PCR and Western blotting further indicated that let-7f downregulated the expression of myosin IIA at the mRNA and protein levels. CONCLUSIONS/SIGNIFICANCE: Our study demonstrated that overexpression of let-7f in gastric cancer could inhibit invasion and migration of gastric cancer cells through directly targeting the tumor metastasis-associated gene MYH9. These data suggest that let-7f may be a novel therapeutic candidate for gastric cancer, given its ability to reduce cell invasion and metastasis
Complexity Evaluation of an Environmental Control and Life-Support System Based on Directed and Undirected Structural Entropy Methods
During manned space missions, an environmental control and life-support system (ECLSS) is employed to meet the life-supporting requirements of astronauts. The ECLSS is a type of hierarchical system, with subsystem—component—single machines, forming a complex structure. Therefore, system-level conceptual designing and performance evaluation of the ECLSS must be conducted. This study reports the top-level scheme of ECLSS, including the subsystems of atmosphere revitalization, water management, and waste management. We propose two schemes based on the design criteria of improving closure and reducing power consumption. In this study, we use the structural entropy method (SEM) to calculate the system order degree to quantitatively evaluate the ECLSS complexity at the top level. The complexity of the system evaluated by directed SEM and undirected SEM presents different rules. The results show that the change in the system structure caused by the replacement of some single technologies will not have great impact on the overall system complexity. The top-level scheme design and complexity evaluation presented in this study may provide technical support for the development of ECLSS in future manned spaceflights
A method to calculate reasonable water injection rate for M oilfield
Abstract In recent years, M oilfield has entered into high water cut stage. Two main problems are imposed in the process of development including sharp water cut rising rate and rapid oil production decline. These problems are difficult to solve, which may bring other problems. In order to slow down production decline rate and control the rising rate of water cut, it is necessary to control water injection rate. However, oil production rate can be affected if water injection rate is too low to provide enough water volume for maintaining reservoir pressure. A method to calculate reasonable injection–production ratio and predict water cut is provided in this paper. Its main mechanism is to resolve above contradictions by calculating reasonable water injection rate. Firstly, an equation to calculate reasonable injection–production ratio is deduced by material balance equation. It considers several parameters including rate of pressure recovery, water cut and other production indexes. Secondly, reasonable oil production rates and water cut of future 10 years are predicted. Oil production is predicted by the law of production decline, and water cut is predicted by regression equation of water drive characteristic curve. Lastly, reasonable water injection rates of next 10 years are calculated through predicted injection–production ratios and liquid production rates. Taking M oilfield as an example, this paper presents a method to determine reasonable water injection rate of multilayer sandstone water drive reservoir
Experimental and Numerical Studies on Static Aeroelastic Behaviours of a Forward-Swept Wing Model
The static aeroelastic behaviours of a flat-plate forward-swept wing model in the vicinity of static divergence are investigated by numerical simulations and wind tunnel tests. A medium fidelity model based on the vortex lattice method (VLM) and nonlinear structural analysis is proposed to calculate the displacements of the wing structure with large deformation. Follower forces effect and geometric nonlinearity are considered to calculate the deformation of the wing by finite element method (FEM). In the wind tunnel tests, the divergence dynamic pressure is predicted by the Southwell method, and the static aeroelastic displacement is measured by a photogrammetric method. The results obtained by the medium fidelity model calculations show reasonable agreement with wind tunnel test results. A high fidelity model based on coupled computational fluid dynamics (CFD) and computational structural dynamics (CSD) predicts better results of the wing tip displacement when the freestream dynamic pressure is approaching the divergence dynamic pressure
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