Column size effects of DER fluids

The static yield stress of dielectric electrorheological(DER) fluids of infinite column state and chain state are calculated from the first principle method. The results indicate that the column surface contributions to ER effects is very small and both states will give correct results to the real DER fluids.Comment: 7 pages, 3 figure

Capturing Topology in Graph Pattern Matching

Graph pattern matching is often defined in terms of subgraph isomorphism, an NP-complete problem. To lower its complexity, various extensions of graph simulation have been considered instead. These extensions allow pattern matching to be conducted in cubic-time. However, they fall short of capturing the topology of data graphs, i.e., graphs may have a structure drastically different from pattern graphs they match, and the matches found are often too large to understand and analyze. To rectify these problems, this paper proposes a notion of strong simulation, a revision of graph simulation, for graph pattern matching. (1) We identify a set of criteria for preserving the topology of graphs matched. We show that strong simulation preserves the topology of data graphs and finds a bounded number of matches. (2) We show that strong simulation retains the same complexity as earlier extensions of simulation, by providing a cubic-time algorithm for computing strong simulation. (3) We present the locality property of strong simulation, which allows us to effectively conduct pattern matching on distributed graphs. (4) We experimentally verify the effectiveness and efficiency of these algorithms, using real-life data and synthetic data.Comment: VLDB201

Research on Spatial Optimization of Shopping Center under the Background of Epidemic Situation : A Case Study of Weilaishi Shopping Center in Handan

In the current social background of frequent epidemics, shopping centers, as commercial buildings with a large number of people, it is very important to reduce the risk of environmental infection. This paper takes the Weilaishi Shopping Center in Handan as an example, summarizes the epidemic prevention status of five types of spatial nodes through field investigation, and analyzes the shortcomings of the existing emergency design of the Weilaishi Shopping Center. Based on the analysis results, this paper puts forward the optimization strategy from the spatial level, which provides a certain reference value for the research on the improvement of shopping center space environment emergency capability

LOCAL DYNAMICS OF ESSENTIAL PROJECTIVE VECTOR FIELDS FOR LEVI-CIVITA CONNECTIONS

We study metrizable projective structures near non-linearizable singularities of projective vector fields. We prove connected 3-dimensional Riemannian manifolds and closed connected pseudo-Riemannian manifolds admitting a projective vector field with a non-linearizable singularity are projectively flat. We also show that a 3-dimensional Lorentzian metric is projectively flat on a cone with its vertex at non-linearizable singularities of projective vector fields

Free electron emission in vacuum assisted by photonic time crystals

The Cerenkov radiation and the Smith-Purcell effect state that free electron emission occurs exclusively in dielectrics when the velocity of the particles exceeds the speed of light in the medium or in the vicinity of periodic gratings close to each other within a vacuum. We demonstrate that free electrons in a vacuum can also emit highly directional monochromatic waves when they are in close proximity to a medium that is periodically modulated temporally, suggesting the existence of temporal Smith-Purcell effect. The momentum band gaps of time-varying media, such as photonic time crystals (PTCs), create new pathways for the injection of external energy, allowing the frequency, intensity, and spatial distribution of the electromagnetic fields to be controlled. Moreover, the PTC substrate enables the conversion of localized evanescent fields into amplified, highly directional propagating plane waves that are only sensitive to the velocity of particles and the modulation frequency, which allows us to observe and utilize Cerenkov-like radiation in free space. Our work exhibits significant opportunities for the utilization of time-varying structures in various fields, including particle identification, ultraweak signal detection, and improved radiation source design

Hyper-Convolution Networks for Biomedical Image Segmentation

The convolution operation is a central building block of neural network architectures widely used in computer vision. The size of the convolution kernels determines both the expressiveness of convolutional neural networks (CNN), as well as the number of learnable parameters. Increasing the network capacity to capture rich pixel relationships requires increasing the number of learnable parameters, often leading to overfitting and/or lack of robustness. In this paper, we propose a powerful novel building block, the hyper-convolution, which implicitly represents the convolution kernel as a function of kernel coordinates. Hyper-convolutions enable decoupling the kernel size, and hence its receptive field, from the number of learnable parameters. In our experiments, focused on challenging biomedical image segmentation tasks, we demonstrate that replacing regular convolutions with hyper-convolutions leads to more efficient architectures that achieve improved accuracy. Our analysis also shows that learned hyper-convolutions are naturally regularized, which can offer better generalization performance. We believe that hyper-convolutions can be a powerful building block in future neural network architectures for computer vision tasks. We provide all of our code here: https://github.com/tym002/Hyper-ConvolutionComment: WACV 202

Collaborative Governance for Responsible Innovation in the Context of Sharing Economy:Studies on the Shared Bicycle Sector in China

The shared bicycle sector is a new type of rental business that combines the sharing economy with technology platforms. With its convenience, efficiency and low cost, the business has become popular in China. However, alongside the development of the shared bicycle industry, the increasing number of products, lack of governance, distrust between companies and users cause problems due to irresponsibility. This paper focuses on the governance of the shared bicycle sector, with the aim of achieving responsible innovation through a collaboration among stakeholders. Through case studies on two cities in China, the paper identifies government policies in the traditional context of hard-law regulation, and in the new context of multi-collaborative governance. The roles of government, industry and society are specified in the innovation ecosystem and are linked with the key dimensions of responsible innovation, anticipation, reflectiveness, inclusiveness and responsiveness. Based on the findings, a model is proposed, suggesting the new government roles of alliance facilitator and platform coordinator. Finally, our recommendations for the improvement of the shared bicycle sector are made and areas for future research are discussed