1,187 research outputs found
ID Embedding as Subtle Features of Content and Structure for Multimodal Recommendation
Multimodal recommendation aims to model user and item representations
comprehensively with the involvement of multimedia content for effective
recommendations. Existing research has shown that it is beneficial for
recommendation performance to combine (user- and item-) ID embeddings with
multimodal salient features, indicating the value of IDs. However, there is a
lack of a thorough analysis of the ID embeddings in terms of feature semantics
in the literature. In this paper, we revisit the value of ID embeddings for
multimodal recommendation and conduct a thorough study regarding its semantics,
which we recognize as subtle features of content and structures. Then, we
propose a novel recommendation model by incorporating ID embeddings to enhance
the semantic features of both content and structures. Specifically, we put
forward a hierarchical attention mechanism to incorporate ID embeddings in
modality fusing, coupled with contrastive learning, to enhance content
representations. Meanwhile, we propose a lightweight graph convolutional
network for each modality to amalgamate neighborhood and ID embeddings for
improving structural representations. Finally, the content and structure
representations are combined to form the ultimate item embedding for
recommendation. Extensive experiments on three real-world datasets (Baby,
Sports, and Clothing) demonstrate the superiority of our method over
state-of-the-art multimodal recommendation methods and the effectiveness of
fine-grained ID embeddings
A Survey on Knowledge Graphs: Representation, Acquisition and Applications
Human knowledge provides a formal understanding of the world. Knowledge
graphs that represent structural relations between entities have become an
increasingly popular research direction towards cognition and human-level
intelligence. In this survey, we provide a comprehensive review of knowledge
graph covering overall research topics about 1) knowledge graph representation
learning, 2) knowledge acquisition and completion, 3) temporal knowledge graph,
and 4) knowledge-aware applications, and summarize recent breakthroughs and
perspective directions to facilitate future research. We propose a full-view
categorization and new taxonomies on these topics. Knowledge graph embedding is
organized from four aspects of representation space, scoring function, encoding
models, and auxiliary information. For knowledge acquisition, especially
knowledge graph completion, embedding methods, path inference, and logical rule
reasoning, are reviewed. We further explore several emerging topics, including
meta relational learning, commonsense reasoning, and temporal knowledge graphs.
To facilitate future research on knowledge graphs, we also provide a curated
collection of datasets and open-source libraries on different tasks. In the
end, we have a thorough outlook on several promising research directions
Robust Temporally Coherent Laplacian Protrusion Segmentation of 3D Articulated Bodies
In motion analysis and understanding it is important to be able to fit a
suitable model or structure to the temporal series of observed data, in order
to describe motion patterns in a compact way, and to discriminate between them.
In an unsupervised context, i.e., no prior model of the moving object(s) is
available, such a structure has to be learned from the data in a bottom-up
fashion. In recent times, volumetric approaches in which the motion is captured
from a number of cameras and a voxel-set representation of the body is built
from the camera views, have gained ground due to attractive features such as
inherent view-invariance and robustness to occlusions. Automatic, unsupervised
segmentation of moving bodies along entire sequences, in a temporally-coherent
and robust way, has the potential to provide a means of constructing a
bottom-up model of the moving body, and track motion cues that may be later
exploited for motion classification. Spectral methods such as locally linear
embedding (LLE) can be useful in this context, as they preserve "protrusions",
i.e., high-curvature regions of the 3D volume, of articulated shapes, while
improving their separation in a lower dimensional space, making them in this
way easier to cluster. In this paper we therefore propose a spectral approach
to unsupervised and temporally-coherent body-protrusion segmentation along time
sequences. Volumetric shapes are clustered in an embedding space, clusters are
propagated in time to ensure coherence, and merged or split to accommodate
changes in the body's topology. Experiments on both synthetic and real
sequences of dense voxel-set data are shown. This supports the ability of the
proposed method to cluster body-parts consistently over time in a totally
unsupervised fashion, its robustness to sampling density and shape quality, and
its potential for bottom-up model constructionComment: 31 pages, 26 figure
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