4,754 research outputs found
Study on the Rheological Properties and Constitutive Model of Shenzhen Mucky Soft Soil
In order to obtain the basic parameters of numerical analysis about the time-space effect of the deformation occurring in Shenzhen deep soft-soil foundation pit, a series of triaxial consolidated-undrained shear rheology tests on the peripheral mucky soft soil of a deep foundation pit support were performed under different confining pressures. The relations between the axial strain of the soil and time, as well as between the pore-water pressure of the soil and time, were achieved, meanwhile on the basis of analyzing the rheological properties of the soil, the relevant rheological models were built. Analysis results were proved that the rheology of Shenzhen mucky soft soil was generally viscous, elastic, and plastic, and had a low yield stress between 90 and 150 kPa. The increase in pore-water pressure made the rheological time effect of the mucky soft soil more remarkable. Thus, the drainage performance in practical engineering should be improved to its maximum possibility extent to decrease the soft-soil rheological deformation. Lastly, a six-component extended Burgers model was employed to fit the test results and the parameters of the model were determined. Findings showed that the extended Burgers model could satisfactorily simulate the various rheological stages of the mucky soft soil. The constitutive model and the determination of its parameters can be served as a foundation for the time-space effect analysis on the deformation of deep soft-soil foundation pits
Effects of dietary chromium on growth, amino acid content and proteomic changes in Sea Cucumber Apostichopus japonicus
781-786To assess the effect of dietary chromium, the growth rate, amino acid content and proteomic changes in the sea cucumber Apostichopus japonicus were compared, when fed with the diets amended with chromium-treated (58.27 mg Cr/kg dry weight) Macrocystis pyrifera and a Cr-free control diet (5.83 mg Cr/kg dry weight). After 10 days, the dietary chromium exposure decreased its growth rate and the amino acid content also changed. The proteomic changes were analyzed in A. japonicus after it was fed for 10 days with Cr-added and Cr-free control diet. The total of 1587 proteins were identified, of which 28 proteins were identified as differentially regulated proteins in sea cucumber to Cr stress. Among them, 10 proteins were identified. In summary, this work reported toxic effects in sea cucumber A. japonicus after dietary exposure to Cr
2,2′,4,4′,6,6′-Hexamethyl-N-(3-phthalimidopropyl)-N,N′-(propane-1,3-diyl)dibenzenesulfonamide
In the title compound, C32H38N3O6S2, an intermediate in the synthesis of polyamine drugs, the dihedral angle between the phenyl rings of the two 2,4,6-trimethylbenzenesulfonyl groups is 27.1 (3)°. In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen bonds, thereby forming an infinite one-dimensional chain propagating along [010]
N,N′-Bis(2-cyanoethyl)-4,4′-dimethyl-N,N′-(butane-1,4-diyl)dibenzenesulfonamide
The complete molecule of the title compound, C24H30N4O4S2, is generated by a crystallographic inversion centre. In the crystal, weak C—H⋯O interactions link the molecules, forming infinite sheets
2-(3-Bromopropyl)isoindoline-1,3-dione
In the title compound, C11H10BrNO2, the dihedral angle between the five- and six-membered rings of the phthalamide system is 1.00 (16)°. There are no significant intermolecular interations except for van der Waals contacts
Multi-Behavior Hypergraph-Enhanced Transformer for Sequential Recommendation
Learning dynamic user preference has become an increasingly important
component for many online platforms (e.g., video-sharing sites, e-commerce
systems) to make sequential recommendations. Previous works have made many
efforts to model item-item transitions over user interaction sequences, based
on various architectures, e.g., recurrent neural networks and self-attention
mechanism. Recently emerged graph neural networks also serve as useful backbone
models to capture item dependencies in sequential recommendation scenarios.
Despite their effectiveness, existing methods have far focused on item sequence
representation with singular type of interactions, and thus are limited to
capture dynamic heterogeneous relational structures between users and items
(e.g., page view, add-to-favorite, purchase). To tackle this challenge, we
design a Multi-Behavior Hypergraph-enhanced Transformer framework (MBHT) to
capture both short-term and long-term cross-type behavior dependencies.
Specifically, a multi-scale Transformer is equipped with low-rank
self-attention to jointly encode behavior-aware sequential patterns from
fine-grained and coarse-grained levels. Additionally, we incorporate the global
multi-behavior dependency into the hypergraph neural architecture to capture
the hierarchical long-range item correlations in a customized manner.
Experimental results demonstrate the superiority of our MBHT over various
state-of-the-art recommendation solutions across different settings. Further
ablation studies validate the effectiveness of our model design and benefits of
the new MBHT framework. Our implementation code is released at:
https://github.com/yuh-yang/MBHT-KDD22.Comment: Published as a KDD'22 full pape
Propulsion Performance Analysis of Wave-powered Boats
With the development of oceanographic research and marine environment protection, mobile marine platforms are applied for ocean observation for a long journey. Wave-powered boats are capable of applying wave motion to propel itself and make a long-duration survey. This paper presents the dynamics of the wave-powered boat under the excitation of the heave motion and pitch motion. Taking the wave-powered boat with double fins as an example, the heave and pitch motions of the boat are obtained by ANSYS-AQWA firstly. Then the relationship between propulsion performance and three factors, including wave height, wave period, and restoring stiffness of torsion spring, was analyzed through multibody dynamics software ADAMS. With the increase of sea state from level 1 to level 4 the average propulsion speed increased from 0.4m/s to 1.4m/s. Under the same wave height and period, with the increase of restoring stiffness of torsion spring from 0.0125N·m/deg to 0.3N·m /deg, the propulsion speed of the wave-powered boat increases first and then decreases, and there exists an optimum stiffness. Through the calculation it is found that when the restoring stiffness of torsional spring is increased from 0.025N·m /deg to 0.2N·m /deg with the sea state level 1 to 4, the wave powered boat has better propulsion performance
CMFDFormer: Transformer-based Copy-Move Forgery Detection with Continual Learning
Copy-move forgery detection aims at detecting duplicated regions in a
suspected forged image, and deep learning based copy-move forgery detection
methods are in the ascendant. These deep learning based methods heavily rely on
synthetic training data, and the performance will degrade when facing new
tasks. In this paper, we propose a Transformer-style copy-move forgery
detection network named as CMFDFormer, and provide a novel PCSD (Pooled Cube
and Strip Distillation) continual learning framework to help CMFDFormer handle
new tasks. CMFDFormer consists of a MiT (Mix Transformer) backbone network and
a PHD (Pluggable Hybrid Decoder) mask prediction network. The MiT backbone
network is a Transformer-style network which is adopted on the basis of
comprehensive analyses with CNN-style and MLP-style backbones. The PHD network
is constructed based on self-correlation computation, hierarchical feature
integration, a multi-scale cycle fully-connected block and a mask
reconstruction block. The PHD network is applicable to feature extractors of
different styles for hierarchical multi-scale information extraction, achieving
comparable performance. Last but not least, we propose a PCSD continual
learning framework to improve the forgery detectability and avoid catastrophic
forgetting when handling new tasks. Our continual learning framework restricts
intermediate features from the PHD network, and takes advantage of both cube
pooling and strip pooling. Extensive experiments on publicly available datasets
demonstrate the good performance of CMFDFormer and the effectiveness of the
PCSD continual learning framework.Comment: 12pages,7 figure
Multiscale isogeometric optimization for cellular structure with multiple prototypes
This paper presents a multiscale concurrent isogeometric design method for the cellular structure composed of the multiple prototype microstructures. Based on the unified-skeleton modeling scheme, the graded microstructures obtained from a same prototype have similar topology and good connectivity between each other. For the different prototypes, the configurations are rearranged and added the thin-wall material in common interfaces. Thus, the geometric features as well as the structural skeletons can have a smooth transition. Through combining the numerical homogenization method with the interpolation technique, the effective properties of graded microstructures can be estimated efficiently. For the multiscale scheme, the allocation of microstructures is optimized by a material distribution-based method while the configurations of prototypes are designed by the isogeometric parameterized level set method. The proposed method inherits the high accuracy and high efficiency of isogeometric analysis and the smooth boundaries and distinct interfaces of level set method. The cellular structure can be freely customized with favorable connectivity
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