33 research outputs found
Bioactive Conserve from Unconventionally Processed Cumin Seeds
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Mitigating technical challenges in brain-computer interfaces for stroke rehabilitation
No full textBrain-computer interfaces (BCIs) provide a means of non-muscular communication by translating brain activity into the control of external devices. Motor imagery (MI) has attracted significant attention among various non-invasive BCI paradigms using electroencephalogram (EEG) for its potential in stroke rehabilitation. However, MI-based BCIs encounter challenges in real-time applications for stroke patients, primarily due to limited reliability and robustness. Additionally, the scarce availability of clinical data impedes the development of cross-subject models for MI detection in stroke patients. Furthermore, the current MI-BCIs do not adequately facilitate the restoration of distal hand functions, which are essential for enhancing the quality of life for individuals with motor impairments. This thesis proposes solutions to address these technical challenges in BCIs for stroke rehabilitation using deep learning (DL) methods. Furthermore, a novel experimental protocol is introduced to enable clinically relevant practical applications of BCIs in stroke patients.
The research begins with an extensive literature review focusing on the impact of EEG discrepancies on the performance of BCIs. The review delves into channel selection and transfer learning techniques that aim to enhance the resilience of EEG-BCIs. Recently, there has been a surge in studies investigating subject-independent models in the domain of MI-BCI. This trend is driven by the superior predictive capabilities of subject-independent models based on DL compared to subject-specific models. However, the literature review highlights a significant gap in the research, as most studies in this area have focused primarily on healthy subjects, with limited inclusion of stroke patients. Furthermore, the review encompasses relevant studies exploring MI decoding from the same limb.
With the goal of selecting the optimal set of EEG channels to enhance overall classification performance in DL-based MI-BCIs, the author proposes subject-independent channel selection using layer-wise relevance propagation (LRP) and neural network pruning. Traditional approaches to channel selection have focused predominantly on subject-specific optimization, whereas subject-independent methods are essential for the utilization of DL models trained on cross-subject data. The proposed methodology not only achieves a significant reduction in the number of channels but also maintains subject-independent classification accuracy, while ensuring interpretability in terms of underlying neural mechanisms.
Furthermore, in consideration of the limited availability of clinical data to train BCI algorithms, the research investigates the feasibility of employing DL models pre-trained on data from healthy individuals to detect MI in stroke patients, while also taking into account the inter-subject variability between the healthy and stroke populations. Through domain adaptation, the transfer learning approach demonstrates improved MI detection accuracy in stroke patients, surpassing subject-specific models. Interpretability analysis using transfer models determines channel relevance patterns that indicate contributions from the bilateral motor, frontal, and parietal regions of the cortex towards MI detection in stroke patients. Furthermore, the healthy-to-stroke transfer learning achieves comparable performance to stroke-to-stroke transfer learning, highlighting its potential to enhance the clinical use of BCI algorithms.
Finally, a novel BCI experiment utilizing a robotic exoskeleton for unilateral hand motor attempt (MA) tasks is introduced. The focus of stroke rehabilitation is often the recovery of distal hand function. A mere act of opening and closing the hand has the potential to bring about significant enhancements in the quality of life experienced by individuals who have suffered from stroke. In this research study, MA-EEG data collected from healthy subjects is employed to develop subject-specific and subject-independent DL models. The results highlight the importance of this experiment in driving advancements in stroke rehabilitation.
This thesis makes novel contributions to the field by optimizing EEG-BCIs for stroke rehabilitation through subject-independent channel selection, transfer learning from healthy to stroke populations, and a new BCI experiment for same-hand MA-EEG decoding. The findings pave the way for more reliable, applicable, and interpretable BCIs, enhancing their potential for clinical use and rehabilitation purposes.Doctor of Philosoph
Using ISO/IEC 12207 to analyze open source software development processes: an E-learning case study
No full textTo date, there is no comprehensive study of open source software development process (OSSDP) carried out for open source (OS) e-learning systems. This paper presents the work which objectively analyzes the open source software development (OSSD) practices carried out by e-learning systems development communities and their results are represented using DEMO models. These results are compared using ISO/IEC 12207:2008. The comparison of DEMO models with ISO/IEC 12207 is a useful contribution; as it provides deeper understanding to-wards the OS e-learning system development
Sub-MeV spectroscopy with AstroSat-CZT imager for gamma ray bursts
No full textCadmium–Zinc–Telluride Imager (CZTI) onboard AstroSat has been a prolific Gamma-Ray Burst (GRB) monitor. While the 2-pixel Compton scattered events (100–300 keV) are used to extract sensitive spectroscopic information, the inclusion of the low-gain pixels (∼ 20% of the detector plane) after careful calibration extends the energy range of Compton energy spectra to 600 keV. The new feature also allows single-pixel spectroscopy of the GRBs to the sub-MeV range which is otherwise limited to 150 keV. We also introduced a new noise rejection algorithm in the analysis (‘Compton noise’). These new additions not only enhances the spectroscopic sensitivity of CZTI, but the sub-MeV spectroscopy will also allow proper characterization of the GRBs not detected by Fermi. This article describes the methodology of single, Compton event and veto spectroscopy in 100–900 keV combined for the GRBs detected in the first year of operation. CZTI in last five years has detected ∼ 20 bright GRBs. The new methodologies, when applied on the spectral analysis for this large sample of GRBs, has the potential to improve the results significantly and help in better understanding the prompt emission mechanism
Prompt Emission Polarimetry of Gamma-Ray Bursts with the AstroSat CZT Imager
No full textX-ray and gamma-ray polarization measurements of the prompt emission of gamma-ray bursts (GRBs) are believed to be extremely important for testing various models of GRBs. So far, the available measurements of hard X-ray polarization of GRB prompt emission have not significantly constrained the GRB models, particularly because of the difficulty of measuring polarization in these bands. The CZT Imager (CZTI) on board AstroSat is primarily an X-ray spectroscopic instrument that also works as a wide-angle GRB monitor due to the transparency of its support structure above 100 keV. It also has experimentally verified polarization measurement capability in the energy range 100-300 keV and thus provides a unique opportunity to attempt spectropolarimetric studies of GRBs. Here we present the polarization data for the brightest 11 GRBs detected by CZTI during its first year of operation. Among these, five GRBs show polarization signatures with 3σ, and one GRB shows 2σ detection significance. We place upper limits for the remaining five GRBs. We provide details of the various tests performed to validate our polarization measurements. While it is difficult yet to discriminate between various emission models with the current sample alone, the large number of polarization measurements that CZTI expects to gather in its minimum lifetime of five years should help to significantly improve our understanding of the prompt emission
AN INSIGHT ON ALGAL CELL DISRUPTION FOR BIODIESEL PRODUCTION
No full text Objective: This review article deals with the effect that various cell disruption techniques have on the efficiency of lipid extraction. We have reviewed existing algal cell disruption techniques that aid the biodiesel production process.Methods: Current rise in demand for energy has led the researcher to focus on the production of sustainable fuels, among which biodiesel has received greater attention. This is due to its larger lipid content, higher growth rate, larger biomass production, and lower land use. Extraction of lipid from algae (micro and macro) for the production of biodiesel involves numerous downstream processing steps, of which cell wall disruption is a crucial step. Bead milling, high-pressure homogenization, ultra-sonication, freeze-drying, acid treatment, and enzymatic lysis are some methods of cell disruption. The cell disruption technique needs to be optimized based on the structure and biochemical composition of algae.Result: The lipid extraction efficiency varies depending on the algal species and the cell disruption technique used.Conclusion: In-depth research and development of new techniques are required to further enhance the cell disruption of the algal cell wall for the enhanced recovery of lipids. In addition, the operating costs and energy consumption should also be optimized for the cost-effective recovery.</jats:p
An analysis of the software development processes of open source E-learning systems
No full textIn recent years there has been a rapid increase in demand for e-learning systems. The software development process plays a crucial role in the design and development of a high-quality e-learning system. However, to date, there is no comprehensive comparative study of open source software (OSS) development process for different OS e-learning systems. This hinders the development of a generalized OSS development process, a key requisite for rapidly developing high-quality OS e-learning systems. This paper provides a full analysis of different existing and successful OS e-learning software systems and the best practices followed in the e-learning development. In particular, this paper investigates the software development activities of Moodle, Dokeos and ILIAS. An activity flow representation that describes their current development practices is constructed individually for all three OS e-learning systems. Further, a comprehensive comparative analysis is carried out that leads to an explicit identification of various development stages of the three OS e-learning systems
A comparitive study of compression decompression scheme using Huffman and selective Huffman techniques
No full textHard X-Ray Polarization Catalog for a Five-year Sample of Gamma-Ray Bursts Using AstroSat CZT Imager
No full textThe Cadmium Zinc Telluride Imager (CZTI) on board AstroSat has been regularly detecting gamma-ray bursts (GRBs) since its launch in 2015. Its sensitivity to polarization measurements at energies above 100 keV allows CZTI to attempt spectropolarimetric studies of GRBs. Here, we present the first catalog of GRB polarization measurements made by CZTI during its first five years of operation. This includes the time-integrated polarization measurements of the prompt emission of 20 GRBs in the energy range 100-600 keV. The sample includes the bright GRBs that were detected within an angle range of 0 degrees-60 degrees and 120 degrees-180 degrees where the instrument has useful polarization sensitivity and is less prone to systematics. We implement a few new modifications in the analysis to enhance the polarimetric sensitivity of the instrument. The majority of the GRBs in the sample are found to possess less/null polarization across the total bursts' duration in contrast to a small fraction of five GRBs that exhibit high polarization. The low polarization across the bursts might be due either to the burst being intrinsically weakly polarized or to a varying polarization angle within the burst even when it is highly polarized. In comparison to POLAR measurements, CZTI has detected a larger number of cases with high polarization. This may be a consequence of the higher energy window of CZTI observations, which results in the sampling of a shorter duration of burst emissions than POLAR, thereby probing emissions with less temporal variation in polarization properties
