A bag-of-features-based framework for human activity representation and recognition

Author(s):  
Mi Zhang ◽  
Alexander A. Sawchuk
Author(s):  
Filiberto Pla ◽  
Pedro Ribeiro ◽  
José Santos-Victor ◽  
Alexandre Bernardino

2014 ◽  
Vol 1044-1045 ◽  
pp. 1007-1010
Author(s):  
Wei Xing Zhu ◽  
Wei Guang Xu ◽  
Guo Lin Hou ◽  
Jun You

In this paper, a novel model, HDP-HMM-SCFG is proposed for representing and classifying activities based on motion trajectories. In the model, activities are represented by stochastic grammar using trajectory, where trajectory segments are considered as observations emitted by the grammar terminals attached with HMMs. Then, by replacing the Euclidian distance in the kernel function of Gaussian radial radix with EMD-DTW, which is proposed to measure the distance between two trajectories by integrating the pros. of both EMD and DTW, multi-class SVM classifier is constructed. Experiments on ASL dataset are carried on to validate our approach.


2017 ◽  
Vol 2017 ◽  
pp. 1-31 ◽  
Author(s):  
Shugang Zhang ◽  
Zhiqiang Wei ◽  
Jie Nie ◽  
Lei Huang ◽  
Shuang Wang ◽  
...  

Human activity recognition (HAR) aims to recognize activities from a series of observations on the actions of subjects and the environmental conditions. The vision-based HAR research is the basis of many applications including video surveillance, health care, and human-computer interaction (HCI). This review highlights the advances of state-of-the-art activity recognition approaches, especially for the activity representation and classification methods. For the representation methods, we sort out a chronological research trajectory from global representations to local representations, and recent depth-based representations. For the classification methods, we conform to the categorization of template-based methods, discriminative models, and generative models and review several prevalent methods. Next, representative and available datasets are introduced. Aiming to provide an overview of those methods and a convenient way of comparing them, we classify existing literatures with a detailed taxonomy including representation and classification methods, as well as the datasets they used. Finally, we investigate the directions for future research.


2007 ◽  
Author(s):  
Luci Fuscaldi Teixeira-Salmela ◽  
Sandra J. Olney ◽  
Revathy Devaraj

2019 ◽  
Author(s):  
Grant Duffy ◽  
Jasmine R Lee

Warming across ice-covered regions will result in changes to both the physical and climatic environment, revealing new ice-free habitat and new climatically suitable habitats for non-native species establishment. Recent studies have independently quantified each of these aspects in Antarctica, where ice-free areas form crucial habitat for the majority of terrestrial biodiversity. Here we synthesise projections of Antarctic ice-free area expansion, recent spatial predictions of non-native species risk, and the frequency of human activities to quantify how these facets of anthropogenic change may interact now and in the future. Under a high-emissions future climate scenario, over a quarter of ice-free area and over 80 % of the ~14 thousand km2 of newly uncovered ice-free area could be vulnerable to invasion by one or more of the modelled non-native species by the end of the century. Ice-free areas identified as vulnerable to non-native species establishment were significantly closer to human activity than unsuitable areas were. Furthermore, almost half of the new vulnerable ice-free area is within 20 km of a site of current human activity. The Antarctic Peninsula, where human activity is heavily concentrated, will be at particular risk. The implications of this for conservation values of Antarctica and the management efforts required to mitigate against it are in need of urgent consideration.


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