1,338 research outputs found

    AUTOMATED ARTIFACT REMOVAL AND DETECTION OF MILD COGNITIVE IMPAIRMENT FROM SINGLE CHANNEL ELECTROENCEPHALOGRAPHY SIGNALS FOR REAL-TIME IMPLEMENTATIONS ON WEARABLES

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    Electroencephalogram (EEG) is a technique for recording asynchronous activation of neuronal firing inside the brain with non-invasive scalp electrodes. EEG signal is well studied to evaluate the cognitive state, detect brain diseases such as epilepsy, dementia, coma, autism spectral disorder (ASD), etc. In this dissertation, the EEG signal is studied for the early detection of the Mild Cognitive Impairment (MCI). MCI is the preliminary stage of Dementia that may ultimately lead to Alzheimers disease (AD) in the elderly people. Our goal is to develop a minimalistic MCI detection system that could be integrated to the wearable sensors. This contribution has three major aspects: 1) cleaning the EEG signal, 2) detecting MCI, and 3) predicting the severity of the MCI using the data obtained from a single-channel EEG electrode. Artifacts such as eye blink activities can corrupt the EEG signals. We investigate unsupervised and effective removal of ocular artifact (OA) from single-channel streaming raw EEG data. Wavelet transform (WT) decomposition technique was systematically evaluated for effectiveness of OA removal for a single-channel EEG system. Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT), is studied with four WT basis functions: haar, coif3, sym3, and bior4.4. The performance of the artifact removal algorithm was evaluated by the correlation coefficients (CC), mutual information (MI), signal to artifact ratio (SAR), normalized mean square error (NMSE), and time-frequency analysis. It is demonstrated that WT can be an effective tool for unsupervised OA removal from single channel EEG data for real-time applications.For the MCI detection from the clean EEG data, we collected the scalp EEG data, while the subjects were stimulated with five auditory speech signals. We extracted 590 features from the Event-Related Potential (ERP) of the collected EEG signals, which included time and spectral domain characteristics of the response. The top 25 features, ranked by the random forest method, were used for classification models to identify subjects with MCI. Robustness of our model was tested using leave-one-out cross-validation while training the classifiers. Best results (leave-one-out cross-validation accuracy 87.9%, sensitivity 84.8%, specificity 95%, and F score 85%) were obtained using support vector machine (SVM) method with Radial Basis Kernel (RBF) (sigma = 10, cost = 102). Similar performances were also observed with logistic regression (LR), further validating the results. Our results suggest that single-channel EEG could provide a robust biomarker for early detection of MCI. We also developed a single channel Electro-encephalography (EEG) based MCI severity monitoring algorithm by generating the Montreal Cognitive Assessment (MoCA) scores from the features extracted from EEG. We performed multi-trial and single-trail analysis for the algorithm development of the MCI severity monitoring. We studied Multivariate Regression (MR), Ensemble Regression (ER), Support Vector Regression (SVR), and Ridge Regression (RR) for multi-trial and deep neural regression for the single-trial analysis. In the case of multi-trial, the best result was obtained from the ER. In our single-trial analysis, we constructed the time-frequency image from each trial and feed it to the convolutional deep neural network (CNN). Performance of the regression models was evaluated by the RMSE and the residual analysis. We obtained the best accuracy with the deep neural regression method

    A high speed Tri-Vision system for automotive applications

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    Purpose: Cameras are excellent ways of non-invasively monitoring the interior and exterior of vehicles. In particular, high speed stereovision and multivision systems are important for transport applications such as driver eye tracking or collision avoidance. This paper addresses the synchronisation problem which arises when multivision camera systems are used to capture the high speed motion common in such applications. Methods: An experimental, high-speed tri-vision camera system intended for real-time driver eye-blink and saccade measurement was designed, developed, implemented and tested using prototype, ultra-high dynamic range, automotive-grade image sensors specifically developed by E2V (formerly Atmel) Grenoble SA as part of the European FP6 project – sensation (advanced sensor development for attention stress, vigilance and sleep/wakefulness monitoring). Results : The developed system can sustain frame rates of 59.8 Hz at the full stereovision resolution of 1280 × 480 but this can reach 750 Hz when a 10 k pixel Region of Interest (ROI) is used, with a maximum global shutter speed of 1/48000 s and a shutter efficiency of 99.7%. The data can be reliably transmitted uncompressed over standard copper Camera-Link® cables over 5 metres. The synchronisation error between the left and right stereo images is less than 100 ps and this has been verified both electrically and optically. Synchronisation is automatically established at boot-up and maintained during resolution changes. A third camera in the set can be configured independently. The dynamic range of the 10bit sensors exceeds 123 dB with a spectral sensitivity extending well into the infra-red range. Conclusion: The system was subjected to a comprehensive testing protocol, which confirms that the salient requirements for the driver monitoring application are adequately met and in some respects, exceeded. The synchronisation technique presented may also benefit several other automotive stereovision applications including near and far-field obstacle detection and collision avoidance, road condition monitoring and others.Partially funded by the EU FP6 through the IST-507231 SENSATION project.peer-reviewe

    FIRE AND LIFE SAFETY ANALYSIS BONDERSON ENGINEERING PROJETS CENTER

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    A Fire and Life Safety Analysis was performed as one of the requirements for the Master of Science Degree in Fire Protection Engineering from California Polytechnic State University San Luis Obispo. The Fire and Life Safety Analysis consists of a prescriptive analysis as well as a performance based analysis. These analyses were performed on the Bonderson Engineering Projects Center which is part of Cal Poly San Luis Obispo. The prescriptive analysis consisted of the four following parts: Egress Analysis and Design, Fire Detection and Alarm Systems, Water-based Fire Suppression, and Structural Fire Protection. The purpose of the prescriptive analysis was to determine if the Bonderson Engineering Projects Center adhered to the codes and standards applicable to the building. The prescriptive analysis was performed using primarily the 2013 edition of the California Building Code (CBC) along with the 2013 editions of NFPA codes. The egress analysis and design met most of the code requirements. One area that the Bonderson Engineering Projects Center did not meet was door swing direction. Room 104 (See Appendix A for building layout) was originally an office classification, but since construction has been utilized as an assembly space. The decreased occupant load factor resulted in a new occupant load which is greater than 50 persons. Per CBC 1008.1.2 exit doors must swing in the direction of egress travel where serving a room or area containing an occupant load of 50 or more persons, which the building does not adhere to. The fire detection and alarm systems analysis was performed primarily utilizing NFPA 72. The building had multiple shortcomings in regards to spacing gaps of the detection devices. These shortcomings were found on the first and second floor, including the lobby, robotics room, project integration room and computer cluster room. The water-based fire suppression system analysis was performed primarily utilizing NFPA 13 and NFPA 25. The water supply and sprinkler system are acceptable. The structural fire protection analysis was performed primarily utilizing the CBC. The main shortcoming discovered was in relation to the atrium. The building must have a 1 hour fire barrier separating atrium spaces from adjacent spaces or it must provide an acceptable smoke control system. The building provides neither of these provisions. The performance based analysis was performed in order to ascertain the ability for the occupant of a building to evacuate safely in the event of a fire. Two separate fire scenarios were evaluated using Fire Dynamics Simulator (FDS) and Pathfinder. Tenability criteria was determined and used in conjunction with FDS in order to determine the available safe egress time (ASET). This was compared against the required safe egress time (RSET) which was determined using Pathfinder. The RSET time was greater than the ASET time, meaning occupants would not be able to safely evacuate the building in the event of an emergency

    University of Southern California Heritage Hall- Fire Protection and Life Safety Analysis

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    This fire protection and life safety analysis is submitted in partial fulfillment of the requirements for the Master of Science Degree from California Polytechnic State University, San Luis Obispo. The study was performed on the University of Southern California’s Heritage Hall, which includes both a code-determined prescriptive examination and a performance-based analysis. The purpose of this review is to evaluate the Heritage Hall address based on compliance with all applicable codes and standards, as well as the determined occupant tenability criteria. The prescriptive examination of Heritage Hall consisted of the evaluation of all structural fire protection, egress analysis and design, water-based fire suppression, and fire alarm systems. This analysis was primarily performed by utilizing the 2013 edition of California Building Code and the 2013 editions of all applicable NFPA codes and standards. The structural fire protection overview provided an in-depth prescriptive analysis of the conversions made for Heritage Hall during the 2012 renovation project. The latest recapitalization expanded the lower level and added more spaces for student athletes, thus converting those locations to the A-3 occupancy classification. Per CBC Table 601, non-bearing walls and partitions were not required to be fire-rated. The structural update complied with all updated building codes due to a water curtain installed per Section 404.6 of the CBC, which allowed the center museum’s atrium not to be separated by a 1-hour fire barrier. Instead, both glass walls surrounding the atrium were used to create smoke partitions to meet standards. The egress analysis and design was utilized to determine new occupant loads for each floor, remove the B-2 occupancy classification, the creation of a new area of refuge. Per CBC Table 1018.1, corridor walls and ceilings were not required to be fire resistance rated due to the building being fully sprinklered. Only the area of refuge at the lower level was provided with a 1-hour fire rated separation, and existing 1-hour separations, such as the lower level’s exit access corridor, remained intact. Using the Life Safety Code, a building evacuation analysis was performed at Heritage Hall’s lower level. The average evacuation time of all lower level occupants was determined to be 5.43 minutes, with a range of 2.74-8.13 minutes depending on whether occupants used the exit corridor or the stairways. All egress components and occupancy classification were deemed acceptable. The water-based suppression analysis was performed by primarily using NFPA 13 and NFPA 25 codes and standards. A complete analysis of the building’s risers, sprinklers, and system demand calculations provided acceptable criteria for the water-based fire protection system installed. The outside overhang was chosen not to have sprinklers installed due to the large amount of remaining asbestos at the interstitial level near the ceiling. The overhang is made of concrete and directly exposed to the outside. The building’s fire alarm system was installed in 2012, with all new fire detection devices, notification appliances, fire alarm control panel, and a mass notification system. The fire alarm system design was analyzed using NFPA 72, with all spacing and location requirements deemed acceptable for the devices installed. All spot-type smoke and heat detectors are ceiling-mounted in accordance with the open ceiling plan at the lower level, which contains both ceiling and wall-mounted sprinklers. The performance-based analysis was performed using Fire Dynamics Simulator (FDS), a fire modeling program provided by NIST, and the SFPE Handbook of Fire Protection Engineering. Two unique design fire performance scenarios were established for Heritage Hall: a workstation fire in the first floor atrium and a stacked-chairs fire near the lower level exit corridor that prevents its use. In order to establish a basis for analysis and comparison, various tenability criteria were determined for the building’s occupants. The performance criteria consisted of visibility, toxicity, and tenability requirements for the facility, which were compared with modeling simulations created using FDS. The simulations allowed for the determination of the available safe egress time (ASET). Occupant behavior and characteristics were paired with Thunderhead Engineering’s Pathfinder program to provide a required set egress time (RSET) for each fire scenario. While the lower level corridor fire scenario met all tenability requirements, the atrium’s fire scenario simulation did not provide an acceptable ASET, and therefore did not pass the critical occupant visibility requirements for safe evacuation. Recommendations were provided to establish a legitimate smoke barrier per CBC Section 404.6, or an appropriate door separation for each side entrance to the atrium per CBC Section 715.1

    Alpha-band rhythms in visual task performance: phase-locking by rhythmic sensory stimulation

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    Oscillations are an important aspect of neuronal activity. Interestingly, oscillatory patterns are also observed in behaviour, such as in visual performance measures after the presentation of a brief sensory event in the visual or another modality. These oscillations in visual performance cycle at the typical frequencies of brain rhythms, suggesting that perception may be closely linked to brain oscillations. We here investigated this link for a prominent rhythm of the visual system (the alpha-rhythm, 8-12 Hz) by applying rhythmic visual stimulation at alpha-frequency (10.6 Hz), known to lead to a resonance response in visual areas, and testing its effects on subsequent visual target discrimination. Our data show that rhythmic visual stimulation at 10.6 Hz: 1) has specific behavioral consequences, relative to stimulation at control frequencies (3.9 Hz, 7.1 Hz, 14.2 Hz), and 2) leads to alpha-band oscillations in visual performance measures, that 3) correlate in precise frequency across individuals with resting alpha-rhythms recorded over parieto-occipital areas. The most parsimonious explanation for these three findings is entrainment (phase-locking) of ongoing perceptually relevant alpha-band brain oscillations by rhythmic sensory events. These findings are in line with occipital alpha-oscillations underlying periodicity in visual performance, and suggest that rhythmic stimulation at frequencies of intrinsic brain-rhythms can be used to reveal influences of these rhythms on task performance to study their functional roles
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