Smartphone Location Recognition with Unknown Modes in Deep Feature Space

Smartphone location recognition aims to identify the location of a smartphone on a user in specific actions such as talking or texting. This task is critical for accurate indoor navigation using pedestrian dead reckoning. Usually, for that task, a supervised network is trained on a set of defined user modes (smartphone locations), available during the training process. In such situations, when the user encounters an unknown mode, the classifier will be forced to identify it as one of the original modes it was trained on. Such classification errors will degrade the navigation solution accuracy. A solution to detect unknown modes is based on a probability threshold of existing modes, yet fails to work with the problem setup. Therefore, to identify unknown modes, two end-to-end ML-based approaches are derived utilizing only the smartphone’s accelerometers measurements. Results using six different datasets shows the ability of the proposed approaches to classify unknown smartphone locations with an accuracy of 93.12%. The proposed approaches can be easily applied to any other classification problems containing unknown modes.

N-Acetylcysteine Attenuates the Anxiety-Like Behavior and Spatial Cognition Impairment Induced by Doxorubicin and Cyclophosphamide Combination Treatment in Rats

<b><i>Background:</i></b> Cancer patients can suffer from psychological and cognitive disorders after chemotherapy, which influence quality of life. <b><i>Objective:</i></b> Oxidative stress may contribute to the psychological and cognitive disorders induced in rats by chemotherapy. In the present study, we examined the effects of N-acetylcysteine, an anti-oxidant, on anxiety-like behavior and cognitive impairment in rats treated with a combination of doxorubicin and cyclophosphamide. <b><i>Methods:</i></b> Rats were intraperitoneally injected with doxorubicin and cyclophosphamide once a week for 2 weeks. The light-dark test and the novel location recognition test were used to assess anxiety-like behavior and spatial cognition, respectively. The rats’ hippocampal levels of glutathione (GSH) and glutathione disulfide (GSSG) were measured using a GSSG/GSH quantification kit. <b><i>Results:</i></b> Combined treatment with doxorubicin and cyclophosphamide produced anxiety-like behavior and cognitive impairment in rats. N-acetylcysteine reversed the anxiety-like behavior and inhibition of novel location recognition induced by the combination treatment. Furthermore, the combination of doxorubicin and cyclophosphamide significantly reduced the rats’ hippocampal GSH/GSSG ratios. N-acetylcysteine reversed the reduction in the GSH/GSSG ratio seen in the doxorubicin and cyclophosphamide-treated rats. <b><i>Conclusion:</i></b> These results suggest that N-acetylcysteine inhibits doxorubicin and cyclophosphamide-induced anxiety-like behavior and cognitive impairment by reducing oxidative stress in the hippocampus.