1,642 research outputs found
Deformable Convolutional Networks
Convolutional neural networks (CNNs) are inherently limited to model
geometric transformations due to the fixed geometric structures in its building
modules. In this work, we introduce two new modules to enhance the
transformation modeling capacity of CNNs, namely, deformable convolution and
deformable RoI pooling. Both are based on the idea of augmenting the spatial
sampling locations in the modules with additional offsets and learning the
offsets from target tasks, without additional supervision. The new modules can
readily replace their plain counterparts in existing CNNs and can be easily
trained end-to-end by standard back-propagation, giving rise to deformable
convolutional networks. Extensive experiments validate the effectiveness of our
approach on sophisticated vision tasks of object detection and semantic
segmentation. The code would be released
Forward Kinematics of Object Transport by a Multi-Robot System with Deformable Sheet
We present object handling and transport by a multi-robot team with a
deformable sheet as a carrier. Due to the deformability of the sheet and the
high dimension of the whole system, it is challenging to clearly describe all
the possible positions of the object on the sheet for a given formation of the
multi-robot system. A complete forward kinematics (FK) method is proposed in
this paper for object handling by an -mobile robot team with a deformable
sheet. Based on the virtual variable cables model, a constrained quadratic
problem (CQP) is formulated by combining the form closure and minimum potential
energy conditions of the system. Analytical solutions to the CQP are presented
and then further verified with the force closure condition. With the proposed
FK method, all possible solutions are obtained with the given initial sheet
shape and the robot team formation. We demonstrate the effectiveness,
completeness, and efficiency of the FK method with simulation and experimental
results.Comment: 8 pages, 6 figures, has been submitted to IEEE Robotics and
Automation Letter
Multi-Robot Object Transport Motion Planning with a Deformable Sheet
Using a deformable sheet to handle objects is convenient and found in many
practical applications. For object manipulation through a deformable sheet that
is held by multiple mobile robots, it is a challenging task to model the
object-sheet interactions. We present a computational model and algorithm to
capture the object position on the deformable sheet with changing robotic team
formations. A virtual variable cables model (VVCM) is proposed to simplify the
modeling of the robot-sheet-object system. With the VVCM, we further present a
motion planner for the robotic team to transport the object in a
three-dimensional (3D) cluttered environment. Simulation and experimental
results with different robot team sizes show the effectiveness and versatility
of the proposed VVCM. We also compare and demonstrate the planning results to
avoid the obstacle in 3D space with the other benchmark planner.Comment: 8 pages, 10 figures, accepted by RAL&CASE 2022 in June 24, 202
Distribution of Heavy Metals in Core Sediments from Baihua Lake
AbstractIn the present research, five core sediments from Baihua Lake, a man-made reservoir located in the karst area on the Yunnan-Guizhou Plateau in China, were analyzed to study the distribution, origin and contamination of three selected heavy metals (Cu, Zn and Mn). The results showed that the concentrations of these heavy metals in sediments varied from different sampling locations and layers. The average concentrations of these heavy metals at the same sampling location followed the order of Mn>Zn>Cu. The mean concentrations of Zn and Mn in the samples at the depth of 0-5cm and the depth of 5-10cm of the core sediments were higher than those in the other layers. All of Cu, Zn and Mn presented similar distribution characteristics at sampling site CFZ, and different distribution characteristics from the other four sampling locations. A statistical analysis indicated that there were some correlations between the concentrations of these three heavy metals and other studied six elements occurring in the core sediment samples. Three components were obtained with principal component analysis (PCA) analysis of heavy metals concentrations in core sediment samples
Data Service Outsourcing and Privacy Protection in Mobile Internet
Mobile Internet data have the characteristics of large scale, variety of patterns, and complex association. On the one hand, it needs efficient data processing model to provide support for data services, and on the other hand, it needs certain computing resources to provide data security services. Due to the limited resources of mobile terminals, it is impossible to complete large-scale data computation and storage. However, outsourcing to third parties may cause some risks in user privacy protection. This monography focuses on key technologies of data service outsourcing and privacy protection, including the existing methods of data analysis and processing, the fine-grained data access control through effective user privacy protection mechanism, and the data sharing in the mobile Internet
Effects of Magnetic Nanoparticles and External Magnetostatic Field on the Bulk Heterojunction Polymer Solar Cells
The price of energy to separate tightly bound electron-hole pair (or charge-transfer state) and extract freely movable charges from low-mobility materials represents fundamental losses for many low-cost photovoltaic devices. In bulk heterojunction (BHJ) polymer solar cells (PSCs), approximately 50% of the total efficiency lost among all energy loss pathways is due to the photogenerated charge carrier recombination within PSCs and low charge carrier mobility of disordered organic materials. To address these issues, we introduce magnetic nanoparticles (MNPs) and orientate these MNPS within BHJ composite by an external magnetostatic field. Over 50% enhanced efficiency was observed from BHJ PSCs incorporated with MNPs and an external magnetostatic field alignment when compared to the control BHJ PSCs. The optimization of BHJ thin film morphology, suppression of charge carrier recombination, and enhancement in charge carrier collection result in a greatly increased short-circuit current density and fill factor, as a result, enhanced power conversion efficiency.
http://dx.doi.org/10.1038/srep0926
Changing Patterns of Spatial Clustering of Schistosomiasis in Southwest China between 1999–2001 and 2007–2008: Assessing Progress toward Eradication after the World Bank Loan Project
We compared changes in the spatial clustering of schistosomiasis in Southwest China at the conclusion of and six years following the end of the World Bank Loan Project (WBLP), the control strategy of which was focused on the large-scale use of chemotherapy. Parasitological data were obtained through standardized surveys conducted in 1999–2001 and again in 2007–2008. Two alternate spatial cluster methods were used to identify spatial clusters of cases: Anselin’s Local Moran’s I test and Kulldorff’s spatial scan statistic. Substantial reductions in the burden of schistosomiasis were found after the end of the WBLP, but the spatial extent of schistosomiasis was not reduced across the study area. Spatial clusters continued to occur in three regions: Chengdu Plain, Yangtze River Valley, and Lancang River Valley during the two periods, and regularly involved five counties. These findings suggest that despite impressive reductions in burden, the hilly and mountainous regions of Southwest China remain at risk of schistosome re-emergence. Our results help to highlight specific locations where integrated control programs can focus to speed the elimination of schistosomiasis in China
NADPH Oxidase 1 and Its Derived Reactive Oxygen Species Mediated Tissue Injury and Repair
Reactive oxygen species are mostly viewed to cause oxidative damage to various cells and induce organ dysfunction after ischemia-reperfusion injury. However, they are also considered as crucial molecules for cellular signal transduction in biology. NADPH oxidase, whose only function is reactive oxygen species production, has been extensively investigated in many cell types especially phagocytes. The deficiency of NADPH oxidase extends the process of inflammation and delays tissue repair, which causes chronic granulomatous disease in patients. NADPH oxidase 1, one member of the NADPH oxidase family, is not only constitutively expressed in a variety of tissues, but also induced to increase expression in both mRNA and protein levels under many circumstances. NADPH oxidase 1 and its derived reactive oxygen species are suggested to be able to regulate inflammation reaction, cell proliferation and migration, and extracellular matrix synthesis, which contribute to the processes of tissue injury and repair
Fusing Monocular Images and Sparse IMU Signals for Real-time Human Motion Capture
Either RGB images or inertial signals have been used for the task of motion
capture (mocap), but combining them together is a new and interesting topic. We
believe that the combination is complementary and able to solve the inherent
difficulties of using one modality input, including occlusions, extreme
lighting/texture, and out-of-view for visual mocap and global drifts for
inertial mocap. To this end, we propose a method that fuses monocular images
and sparse IMUs for real-time human motion capture. Our method contains a dual
coordinate strategy to fully explore the IMU signals with different goals in
motion capture. To be specific, besides one branch transforming the IMU signals
to the camera coordinate system to combine with the image information, there is
another branch to learn from the IMU signals in the body root coordinate system
to better estimate body poses. Furthermore, a hidden state feedback mechanism
is proposed for both two branches to compensate for their own drawbacks in
extreme input cases. Thus our method can easily switch between the two kinds of
signals or combine them in different cases to achieve a robust mocap. %The two
divided parts can help each other for better mocap results under different
conditions. Quantitative and qualitative results demonstrate that by delicately
designing the fusion method, our technique significantly outperforms the
state-of-the-art vision, IMU, and combined methods on both global orientation
and local pose estimation. Our codes are available for research at
https://shaohua-pan.github.io/robustcap-page/.Comment: Accepted by SIGGRAPH ASIA 2023. Project page:
https://shaohua-pan.github.io/robustcap-page
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