Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spatio-Temporal Dynamic Inference Network for Group Activity Recognition   Group activity recognition aims to understand the activity performed by a
group of people. In order to solve it, modeling complex spatio-temporal
interactions is the key. Previous methods are limited in reasoning on a
predefined graph, which ignores the inherent person-specific interaction
context. Moreover, they adopt inference schemes that are computationally
expensive and easily result in the over-smoothing problem. In this paper, we
manage to achieve spatio-temporal person-specific inferences by proposing
Dynamic Inference Network (DIN), which composes of Dynamic Relation (DR) module
and Dynamic Walk (DW) module. We firstly propose to initialize interaction
fields on a primary spatio-temporal graph. Within each interaction field, we
apply DR to predict the relation matrix and DW to predict the dynamic walk
offsets in a joint-processing manner, thus forming a person-specific
interaction graph. By updating features on the specific graph, a person can
possess a global-level interaction field with a local initialization.
Experiments indicate both modules' effectiveness. Moreover, DIN achieves
significant improvement compared to previous state-of-the-art methods on two
popular datasets under the same setting, while costing much less computation
overhead of the reasoning module.

28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th