scholarly journals On Using Temporal Features to Create More Accurate Human-Activity Classifiers

Author(s):  
Juan Ye ◽  
Adrian K. Clear ◽  
Lorcan Coyle ◽  
Simon Dobson
F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 1261
Author(s):  
Sarmela Raja Sekaran ◽  
Pang Ying Han ◽  
Goh Fan Ling ◽  
Ooi Shih Yin

Background: In recent years, human activity recognition (HAR) has been an active research topic due to its widespread application in various fields such as healthcare, sports, patient monitoring, etc. HAR approaches can be categorised as handcrafted feature methods (HCF) and deep learning methods (DL). HCF involves complex data pre-processing and manual feature extraction in which the models may be exposed to high bias and crucial implicit pattern loss. Hence, DL approaches are introduced due to their exceptional recognition performance. Convolutional Neural Network (CNN) extracts spatial features while preserving localisation. However, it hardly captures temporal features. Recurrent Neural Network (RNN) learns temporal features, but it is susceptible to gradient vanishing and suffers from short-term memory problems. Unlike RNN, Long-Short Term Memory network has a relatively longer-term dependency. However, it consumes higher computation and memory because it computes and stores partial results at each level. Methods: This work proposes a novel multiscale temporal convolutional network (MSTCN) based on the Inception model with a temporal convolutional architecture. Unlike HCF methods, MSTCN requires minimal pre-processing and no manual feature engineering. Further, multiple separable convolutions with different-sized kernels are used in MSTCN for multiscale feature extraction. Dilations are applied to each separable convolution to enlarge the receptive fields without increasing the model parameters. Moreover, residual connections are utilised to prevent information loss and gradient vanishing. These features enable MSTCN to possess a longer effective history while maintaining a relatively low in-network computation. Results: The performance of MSTCN is evaluated on UCI and WISDM datasets using subject independent protocol with no overlapping subjects between the training and testing sets. MSTCN achieves F1 scores of 0.9752 on UCI and 0.9470 on WISDM. Conclusion: The proposed MSTCN dominates the other state-of-the-art methods by acquiring high recognition accuracies without requiring any manual feature engineering.


1995 ◽  
Vol 38 (5) ◽  
pp. 1014-1024 ◽  
Author(s):  
Robert L. Whitehead ◽  
Nicholas Schiavetti ◽  
Brenda H. Whitehead ◽  
Dale Evan Metz

The purpose of this investigation was twofold: (a) to determine if there are changes in specific temporal characteristics of speech that occur during simultaneous communication, and (b) to determine if known temporal rules of spoken English are disrupted during simultaneous communication. Ten speakers uttered sentences consisting of a carrier phrase and experimental CVC words under conditions of: (a) speech, (b) speech combined with signed English, and (c) speech combined with signed English for every word except the CVC word that was fingerspelled. The temporal features investigated included: (a) sentence duration, (b) experimental CVC word duration, (c) vowel duration in experimental CVC words, (d) pause duration before and after experimental CVC words, and (e) consonantal effects on vowel duration. Results indicated that for all durational measures, the speech/sign/fingerspelling condition was longest, followed by the speech/sign condition, with the speech condition being shortest. It was also found that for all three speaking conditions, vowels were longer in duration when preceding voiced consonants than vowels preceding their voiceless cognates, and that a low vowel was longer in duration than a high vowel. These findings indicate that speakers consistently reduced their rate of speech when using simultaneous communication, but did not violate these specific temporal rules of English important for consonant and vowel perception.


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.


Author(s):  
Pierre Aubenque

Pierre Aubenque’s “Science Regained” (1962; translated by Clayton Shoppa) was originally published as the concluding chapter of Le Problème de l’Être chez Aristote, one of the most important and original books on Aristotle’s Metaphysics. In this essay, Aubenque contends that the impasses which beset the project of first philosophy paradoxically become its greatest accomplishments. Although science stabilizes motion and thereby introduces necessity into human cognition, human thought always occurs amidst an inescapable movement of change and contingency. Aristotle’s ontology, as a discourse that strives to achieve being in its unity, succeeds by means of the failure of the structure of its own approach: the search of philosophy – dialectic – becomes the philosophy of the search. Aubenque traces this same structure of scission, mediation, and recovery across Aristotelian discussions of theology, motion, time, imitation, and human activity.


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