1,573 research outputs found
Intramolecular Torque, an Indicator of the Internal Rotation Direction of Rotor Molecules and Similar Systems
Torque is ubiquitous in many molecular systems, including collisions,
chemical reactions, vibrations, electronic excitations and especially rotor
molecules. We present a straightforward theoretical method based on forces
acting on atoms and obtained from atomistic quantum mechanics calculations, to
quickly and qualitatively determine whether a molecule or sub-unit thereof has
a tendency to rotation and, if so, around which axis and in which sense:
clockwise or counterclockwise. The method also indicates which atoms, if any,
are predominant in causing the rotation. Our computational approach can in
general efficiently provide insights into the rotational ability of many
molecules and help to theoretically screen or modify them in advance of
experiments or before analyzing their rotational behavior in more detail with
more extensive computations guided by the results from the torque approach. As
an example, we demonstrate the effectiveness of the approach using a specific
light-driven molecular rotary motor which was successfully synthesized and
analyzed in prior experiments and simulations.Comment: 11 pages, 4 figures, 1 SI fil
WGCN: Graph Convolutional Networks with Weighted Structural Features
Graph structural information such as topologies or connectivities provides
valuable guidance for graph convolutional networks (GCNs) to learn nodes'
representations. Existing GCN models that capture nodes' structural information
weight in- and out-neighbors equally or differentiate in- and out-neighbors
globally without considering nodes' local topologies. We observe that in- and
out-neighbors contribute differently for nodes with different local topologies.
To explore the directional structural information for different nodes, we
propose a GCN model with weighted structural features, named WGCN. WGCN first
captures nodes' structural fingerprints via a direction and degree aware Random
Walk with Restart algorithm, where the walk is guided by both edge direction
and nodes' in- and out-degrees. Then, the interactions between nodes'
structural fingerprints are used as the weighted node structural features. To
further capture nodes' high-order dependencies and graph geometry, WGCN embeds
graphs into a latent space to obtain nodes' latent neighbors and geometrical
relationships. Based on nodes' geometrical relationships in the latent space,
WGCN differentiates latent, in-, and out-neighbors with an attention-based
geometrical aggregation. Experiments on transductive node classification tasks
show that WGCN outperforms the baseline models consistently by up to 17.07% in
terms of accuracy on five benchmark datasets
Using Artificial Neural Networks to Produce High-Resolution Soil Property Maps
High-resolution maps of soil property are considered as the most important inputs for decision support and policy-making in agriculture, forestry, flood control, and environmental protection. Commonly, soil properties are mainly obtained from field surveys. Field soil surveys are generally time-consuming and expensive, with a limitation of application throughout a large area. As such, high-resolution soil property maps are only available for small areas, very often, being obtained for research purposes. In the chapter, artificial neural network (ANN) models were introduced to produce high-resolution maps of soil property. It was found that ANNs can be used to predict high-resolution soil texture, soil drainage classes, and soil organic content across landscape with reasonable accuracy and low cost. Expanding applications of the ANNs were also presented
Sectional normalization and recognization on the PV-Diagram of reciprocating compressor
The shortcomings of familiar normalization method on the PV-Diagram of reciprocating compressor are analyzed in the paper. A sectional normalization method of the PV-Diagram was put forward, and a recognizing technique of fault characteristics based on support vector machines for cylinder and piston system in reciprocating compressor is introduced. Four sections of curve in the PV-Diagram indicate four stages of a gas compression cycle. After the PV-Diagram is normalized with the new method, the curvilinear curvatures are unchanged in comparison with the original diagram. The contour and shape relations between normal and fault state character curves are retained. The pressure signals collected from cylinder are normalized and treated as characteristic vectors, and the vectors are inputted into a multi-class classifier composed of many support vector machines in order to classify fault modes. The experimental results show that the method can identify faults of the cylinder and piston system more correctly
AutoAlign: Fully Automatic and Effective Knowledge Graph Alignment enabled by Large Language Models
The task of entity alignment between knowledge graphs (KGs) aims to identify
every pair of entities from two different KGs that represent the same entity.
Many machine learning-based methods have been proposed for this task. However,
to our best knowledge, existing methods all require manually crafted seed
alignments, which are expensive to obtain. In this paper, we propose the first
fully automatic alignment method named AutoAlign, which does not require any
manually crafted seed alignments. Specifically, for predicate embeddings,
AutoAlign constructs a predicate-proximity-graph with the help of large
language models to automatically capture the similarity between predicates
across two KGs. For entity embeddings, AutoAlign first computes the entity
embeddings of each KG independently using TransE, and then shifts the two KGs'
entity embeddings into the same vector space by computing the similarity
between entities based on their attributes. Thus, both predicate alignment and
entity alignment can be done without manually crafted seed alignments.
AutoAlign is not only fully automatic, but also highly effective. Experiments
using real-world KGs show that AutoAlign improves the performance of entity
alignment significantly compared to state-of-the-art methods.Comment: 14 pages, 5 figures, 4 tables. arXiv admin note: substantial text
overlap with arXiv:2210.0854
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