1,239 research outputs found
Methods of Hierarchical Clustering
We survey agglomerative hierarchical clustering algorithms and discuss
efficient implementations that are available in R and other software
environments. We look at hierarchical self-organizing maps, and mixture models.
We review grid-based clustering, focusing on hierarchical density-based
approaches. Finally we describe a recently developed very efficient (linear
time) hierarchical clustering algorithm, which can also be viewed as a
hierarchical grid-based algorithm.Comment: 21 pages, 2 figures, 1 table, 69 reference
A Survey on Few-Shot Class-Incremental Learning
Large deep learning models are impressive, but they struggle when real-time
data is not available. Few-shot class-incremental learning (FSCIL) poses a
significant challenge for deep neural networks to learn new tasks from just a
few labeled samples without forgetting the previously learned ones. This setup
easily leads to catastrophic forgetting and overfitting problems, severely
affecting model performance. Studying FSCIL helps overcome deep learning model
limitations on data volume and acquisition time, while improving practicality
and adaptability of machine learning models. This paper provides a
comprehensive survey on FSCIL. Unlike previous surveys, we aim to synthesize
few-shot learning and incremental learning, focusing on introducing FSCIL from
two perspectives, while reviewing over 30 theoretical research studies and more
than 20 applied research studies. From the theoretical perspective, we provide
a novel categorization approach that divides the field into five subcategories,
including traditional machine learning methods, meta-learning based methods,
feature and feature space-based methods, replay-based methods, and dynamic
network structure-based methods. We also evaluate the performance of recent
theoretical research on benchmark datasets of FSCIL. From the application
perspective, FSCIL has achieved impressive achievements in various fields of
computer vision such as image classification, object detection, and image
segmentation, as well as in natural language processing and graph. We summarize
the important applications. Finally, we point out potential future research
directions, including applications, problem setups, and theory development.
Overall, this paper offers a comprehensive analysis of the latest advances in
FSCIL from a methodological, performance, and application perspective
Human Motion Trajectory Prediction: A Survey
With growing numbers of intelligent autonomous systems in human environments,
the ability of such systems to perceive, understand and anticipate human
behavior becomes increasingly important. Specifically, predicting future
positions of dynamic agents and planning considering such predictions are key
tasks for self-driving vehicles, service robots and advanced surveillance
systems. This paper provides a survey of human motion trajectory prediction. We
review, analyze and structure a large selection of work from different
communities and propose a taxonomy that categorizes existing methods based on
the motion modeling approach and level of contextual information used. We
provide an overview of the existing datasets and performance metrics. We
discuss limitations of the state of the art and outline directions for further
research.Comment: Submitted to the International Journal of Robotics Research (IJRR),
37 page
AutoEncoding Tree for City Generation and Applications
City modeling and generation have attracted an increased interest in various
applications, including gaming, urban planning, and autonomous driving. Unlike
previous works focused on the generation of single objects or indoor scenes,
the huge volumes of spatial data in cities pose a challenge to the generative
models. Furthermore, few publicly available 3D real-world city datasets also
hinder the development of methods for city generation. In this paper, we first
collect over 3,000,000 geo-referenced objects for the city of New York, Zurich,
Tokyo, Berlin, Boston and several other large cities. Based on this dataset, we
propose AETree, a tree-structured auto-encoder neural network, for city
generation. Specifically, we first propose a novel Spatial-Geometric Distance
(SGD) metric to measure the similarity between building layouts and then
construct a binary tree over the raw geometric data of building based on the
SGD metric. Next, we present a tree-structured network whose encoder learns to
extract and merge spatial information from bottom-up iteratively. The resulting
global representation is reversely decoded for reconstruction or generation. To
address the issue of long-dependency as the level of the tree increases, a Long
Short-Term Memory (LSTM) Cell is employed as a basic network element of the
proposed AETree. Moreover, we introduce a novel metric, Overlapping Area Ratio
(OAR), to quantitatively evaluate the generation results. Experiments on the
collected dataset demonstrate the effectiveness of the proposed model on 2D and
3D city generation. Furthermore, the latent features learned by AETree can
serve downstream urban planning applications
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