385 research outputs found
Bootstrapping Witten diagrams via differential representation in Mellin space
We explore the use of the differential representation of AdS amplitudes to compute Witten diagrams. The differential representation expresses AdS amplitudes in terms of conformal generators acting on contact Witten diagrams, which allows us to construct differential equations for Witten diagrams. These differential equations can then be transformed into difference equations in Mellin space, which can be solved recursively. Using this method, we efficiently re-computed scalar four-point amplitudes and obtained new results for scalar six-point amplitudes mediated by gluons and scalars, as well as two examples of scalar eight-point amplitudes from gluon exchange
A New Method for Piecewise Linear Representation of Time Series Data
AbstractIn various methods of modeling of time series, the piecewise linear representation has the advantage of being simple, straightforward and supporting dynamic incremental update of time series. This paper proposed a new method of Piecewise Linear Representation of Time Series based on Slope Change Threshold (SCT). Detailed experiments on real datasets from various fields show that STC representation, compared with several other Piecewise Linear Representations, can be easily calculated and has a high degree of fitting
Cognitive Personalized Search Integrating Large Language Models with an Efficient Memory Mechanism
Traditional search engines usually provide identical search results for all
users, overlooking individual preferences. To counter this limitation,
personalized search has been developed to re-rank results based on user
preferences derived from query logs. Deep learning-based personalized search
methods have shown promise, but they rely heavily on abundant training data,
making them susceptible to data sparsity challenges. This paper proposes a
Cognitive Personalized Search (CoPS) model, which integrates Large Language
Models (LLMs) with a cognitive memory mechanism inspired by human cognition.
CoPS employs LLMs to enhance user modeling and user search experience. The
cognitive memory mechanism comprises sensory memory for quick sensory
responses, working memory for sophisticated cognitive responses, and long-term
memory for storing historical interactions. CoPS handles new queries using a
three-step approach: identifying re-finding behaviors, constructing user
profiles with relevant historical information, and ranking documents based on
personalized query intent. Experiments show that CoPS outperforms baseline
models in zero-shot scenarios.Comment: Accepted by WWW 202
MotionBEV: Attention-Aware Online LiDAR Moving Object Segmentation with Bird's Eye View based Appearance and Motion Features
Identifying moving objects is an essential capability for autonomous systems,
as it provides critical information for pose estimation, navigation, collision
avoidance, and static map construction. In this paper, we present MotionBEV, a
fast and accurate framework for LiDAR moving object segmentation, which
segments moving objects with appearance and motion features in the bird's eye
view (BEV) domain. Our approach converts 3D LiDAR scans into a 2D polar BEV
representation to improve computational efficiency. Specifically, we learn
appearance features with a simplified PointNet and compute motion features
through the height differences of consecutive frames of point clouds projected
onto vertical columns in the polar BEV coordinate system. We employ a
dual-branch network bridged by the Appearance-Motion Co-attention Module (AMCM)
to adaptively fuse the spatio-temporal information from appearance and motion
features. Our approach achieves state-of-the-art performance on the
SemanticKITTI-MOS benchmark. Furthermore, to demonstrate the practical
effectiveness of our method, we provide a LiDAR-MOS dataset recorded by a
solid-state LiDAR, which features non-repetitive scanning patterns and a small
field of view
A Comparison of Molecular Biology Mechanism of Shewanella putrefaciens between Fresh and Terrestrial Sewage Wastewater
Municipal and industrial wastewater is often discharged into the environment without appropriate treatment, especially in developing countries. As a result, many rivers and oceans are contaminated. It is urgent to control and administer treatments to these contaminated rivers and oceans. However, most mechanisms of bacterial colonization in contaminated rivers and oceans were unknown, especially in sewage outlets. We found Shewanella putrefaciens to be the primary bacteria in the terrestrial sewage wastewater outlets around Ningbo City, China. Therefore, in this study, we applied a combination of differential proteomics, metabolomics, and real-time fluorescent quantitative PCR techniques to identify bacteria intracellular metabolites. We found S. putrefaciens had 12 different proteins differentially expressed in freshwater culture than when grown in wastewater, referring to the formation of biological membranes (Omp35, OmpW), energy metabolism (SOD, deoxyribose-phosphate pyrophosphokinase), fatty acid metabolism (beta-ketoacyl synthase), secondary metabolism, TCA cycle, lysine degradation (2-oxoglutarate reductase), and propionic acid metabolism (succinyl coenzyme A synthetase). The sequences of these 12 differentially expressed proteins were aligned with sequences downloaded from NCBI. There are also 27 differentially concentrated metabolites detected by NMR, including alcohols (ethanol, isopropanol), amines (dimethylamine, ethanolamine), amino acids (alanine, leucine), amine compounds (bilinerurine), nucleic acid compounds (nucleosides, inosines), organic acids (formate, acetate). Formate and ethanolamine show significant difference between the two environments and are possibly involved in energy metabolism, glycerophospholipid and ether lipids metabolism to provide energy supply and material basis for engraftment in sewage. Because understanding S. putrefaciens’s biological mechanism of colonization (protein, gene express and metabolites) in terrestrial sewage outlets is so important to administering and improving contaminated river and to predicting and steering performance, we delved into the biological mechanism that sheds light on the effect of environmental conditions on metabolic pathways
Trajectory-Based Spatiotemporal Entity Linking
Trajectory-based spatiotemporal entity linking is to match the same moving
object in different datasets based on their movement traces. It is a
fundamental step to support spatiotemporal data integration and analysis. In
this paper, we study the problem of spatiotemporal entity linking using
effective and concise signatures extracted from their trajectories. This
linking problem is formalized as a k-nearest neighbor (k-NN) query on the
signatures. Four representation strategies (sequential, temporal, spatial, and
spatiotemporal) and two quantitative criteria (commonality and unicity) are
investigated for signature construction. A simple yet effective dimension
reduction strategy is developed together with a novel indexing structure called
the WR-tree to speed up the search. A number of optimization methods are
proposed to improve the accuracy and robustness of the linking. Our extensive
experiments on real-world datasets verify the superiority of our approach over
the state-of-the-art solutions in terms of both accuracy and efficiency.Comment: 15 pages, 3 figures, 15 table
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