3,101 research outputs found
Calibration-Free Driver Drowsiness Classification based on Manifold-Level Augmentation
Drowsiness reduces concentration and increases response time, which causes
fatal road accidents. Monitoring drivers' drowsiness levels by
electroencephalogram (EEG) and taking action may prevent road accidents. EEG
signals effectively monitor the driver's mental state as they can monitor brain
dynamics. However, calibration is required in advance because EEG signals vary
between and within subjects. Because of the inconvenience, calibration has
reduced the accessibility of the brain-computer interface (BCI). Developing a
generalized classification model is similar to domain generalization, which
overcomes the domain shift problem. Especially data augmentation is frequently
used. This paper proposes a calibration-free framework for driver drowsiness
state classification using manifold-level augmentation. This framework
increases the diversity of source domains by utilizing features. We
experimented with various augmentation methods to improve the generalization
performance. Based on the results of the experiments, we found that deeper
models with smaller kernel sizes improved generalizability. In addition,
applying an augmentation at the manifold-level resulted in an outstanding
improvement. The framework demonstrated the capability for calibration-free
BCI.Comment: Submitted to 2023 11th IEEE International Winter Conference on
Brain-Computer Interfac
Creating Value with Acquisition Based Dynamic Capabilities (ABDC): A Study of Mergers and Acquisitions in the Regulated Energy Industry
M&A research has consistently shown that value is destroyed for a majority of acquirers. Despite initial small positive gains at deal announcement, within a year of closing the transaction a majority of acquirers experience overall negative returns. Nevertheless, the constant pressures to grow leave company leaders few other viable options than pursuing M&A. This ever present cycle of value destruction is of interest to both scholars and practitioners. Of interest is what can be done differently by the acquirer to prevent the inevitable value erosion from occurring. To investigate this question, the author develops an adapted version of the Acquisition Based Dynamic Capabilities (ABDC) framework, a theoretical extension of Dynamic Capability theory. The framework is helpful in identifying what corporate M&A capabilities contribute to value creation through a transaction lifecycle. The adapted ABDC framework provides a means to quantify the differing impacts to value creation among the M&A capabilities of “Selecting and Identifying”, “Transacting and Executing” and “Reconfiguring and Integrating”.
The empirical study utilizes 337 regulated energy, public company transactions, closed between 1995 and 2014. This industry is appropriate to study the application of this theory as it benefits from long dated deal timelines and specific milestone events (deal announcement, regulatory approval, financial closing, etc.) providing clear points of delineation for measurement purposes. Performance is measured using weak and semi-strong specifications of shareholder returns with a “golden set” of measures identified. Additionally, the impacts on the ABDC measures from shock waves, bandwagon effects, management traits, financial factors, deal complexity and other relevant factors are all evaluated to test for their impacts on the analyzed transactions. The results suggest that despite many acquirers receiving some positive value accretion from announcement and short-term post-closing returns, larger one year post-close reductions in value eclipse previous gains for most acquirers. The results validate the importance of the Reconfiguring and Integrating (R&I) phase of an acquisition. Comparisons to Top and Poor Performers provide a clear set of recommendations for future energy industry acquirers
Pioneering EEG Motor Imagery Classification Through Counterfactual Analysis
The application of counterfactual explanation (CE) techniques in the realm of
electroencephalography (EEG) classification has been relatively infrequent in
contemporary research. In this study, we attempt to introduce and explore a
novel non-generative approach to CE, specifically tailored for the analysis of
EEG signals. This innovative approach assesses the model's decision-making
process by strategically swapping patches derived from time-frequency analyses.
By meticulously examining the variations and nuances introduced in the
classification outcomes through this method, we aim to derive insights that can
enhance interpretability. The empirical results obtained from our experimental
investigations serve not only to validate the efficacy of our proposed approach
but also to reinforce human confidence in the model's predictive capabilities.
Consequently, these findings underscore the significance and potential value of
conducting further, more extensive research in this promising direction
Optofluidic ring resonator laser with an edible liquid laser gain medium
We demonstrate a biocompatible optofluidic laser with an edible liquid laser gain medium, made of riboflavin dissolved in water. The proposed laser platform is based on a pulled-glass-capillary optofluidic ring resonator (OFRR) with a high Q-factor, resulting in a lasing threshold comparable to that of conventional organic dye lasers that are mostly harmful, despite the relatively low quantum yield of the riboflavin. The proposed biocompatible laser can be realized by not only a capillary OFRR, but also by an optical-fiber-based OFRR that offers improved mechanical stability, and is promising technology for application to in vivo bio-sensing
Deep Chandra Monitoring Observations of NGC 4649: II. Wide-Field Hubble Space Telescope Imaging of the Globular Clusters
We present g and z photometry and size estimates for globular clusters (GCs)
in the massive Virgo elliptical NGC 4649 (M60) using a five-pointing Hubble
Space Telescope/Advanced Camera for Surveys mosaic. The metal-poor GCs show a
monotonic negative metallicity gradient of (-0.43 +/- 0.10) dex per dex in
radius over the full radial range of the data, out to ~ 24 kpc. There is
evidence for substantial color substructure among the metal-rich GCs. The
metal-poor GCs have typical sizes ~ 0.4 pc larger than the metal-rich GCs out
to large galactocentric distances (~> 20 kpc), favoring an intrinsic
explanation for the size difference rather than projection effects. There is no
clear relation between half-light radius and galactocentric distance beyond ~
15 kpc, suggesting that the sizes of GCs are not generically set by tidal
limitation. Finally, we identify ~ 20 candidate ultra-compact dwarfs that
extend down to surprisingly faint absolute magnitudes (M_z ~ -8.5), and may
bridge the gap between this class and "extended clusters" in the Local Group.
Three of the brighter candidates have published radial velocities and can be
confirmed as bona fide ultra-compact dwarfs; follow-up spectroscopy will
determine the nature of the remainder of the candidates.Comment: ApJ in press. For redacted long table 1, see:
http://www.pa.msu.edu/~strader/4649/table.te
Heart rate variability as a preictal marker for determining the laterality of seizure onset zone in frontal lobe epilepsy
Determining the laterality of the seizure onset zone is challenging in frontal lobe epilepsy (FLE) due to the rapid propagation of epileptic discharges to the contralateral hemisphere. There is hemispheric lateralization of autonomic control, and heart rate is modulated by interactions between the sympathetic and parasympathetic nervous systems. Based on this notion, the laterality of seizure foci in FLE might be determined using heart rate variability (HRV) parameters. We explored preictal markers for differentiating the laterality of seizure foci in FLE using HRV parameters. Twelve patients with FLE (6 right FLE and 6 left FLE) were included in the analyzes. A total of 551 (460 left FLE and 91 right FLE) 1-min epoch electrocardiography data were used for HRV analysis. We found that most HRV parameters differed between the left and right FLE groups. Among the machine learning algorithms applied in this study, the light gradient boosting machine was the most accurate, with an AUC value of 0.983 and a classification accuracy of 0.961. Our findings suggest that HRV parameter-based laterality determination models can be convenient and effective tools in clinical settings. Considering that heart rate can be easily measured in real time with a wearable device, our proposed method can be applied to a closed-loop device as a real-time monitoring tool for determining the side of stimulation
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