407 research outputs found
Spatiotemporal parameters measurement of human gait using developed FSR for prosthetic knee joint
No full textMeasuring the heel strike and toe time during walking provides valuable insight to the spatiotemporal parameters of human gait. The authors developed a sensor mechanism using FSR. Result shows that FSR sensor show high degree of accuracy and repeatability for measuring heel strike and toe contact time. The objective of the research was to develop a rugged and robust sensor mechanism to be used in prosthetic shoes which will help to determine the gait parameters for precise control of intelligent prosthetic devices.
Neelesh Kumar, Davinder Pal Singh, Amod Kumar, B.S. Soh
FES supported sitting-standing-sitting of completely paraplegic patient
No full textPaper describes successful achievement of sitting standing function for a completely paraplegic patient by using a newlydeveloped four-channel FES stimulator. Microcontroller governs open loop control system for predefined and measuredstimulation parameters. Surface electrodes are used to give stimulation.
Kumar, Neelesh
Pankaj, Dinesh
Sharma, V K
Agnihotri, R C
Jindal, Rohi
Minimum error probability MIMO-aided relaying: multihop, parallel, and cognitive designs
No full textA design methodology based on the minimum error probability (MEP) framework is proposed for a nonregenerative multiple-input multiple-output (MIMO) relayaided system. We consider the associated cognitive, the parallel and the multi-hop source-relay-destination (SRD) link design based on this MEP framework, including the transmit precoder, the amplify-and-forward (AF) relay matrix and the receiver equalizer matrix of our system. It has been shown in the literature that MEP based communication systems are capable of improving the error probability of other linear counterparts. Our simulation results demonstrate that the proposed scheme indeed achieves a significant BER reduction over the existing linear schemes
Highly Accurate Finite Difference Schemes for the Three-Dimensional Helmholtz Equation
No full textA highly accurate sixth-order compact finite difference scheme is proposed for the three-dimensional Helmholtz equation in a homogeneous medium. A hybrid scheme, a combination of two schemes, is also proposed for the Helmholtz equation. The proposed schemes are illustrated by four examples, the first two of which arise in acoustics, while the last two arise in electromagnetics. Numerical experiments demonstrate that the proposed schemes have very high accuracy in comparison to available schemes for the three-dimensional Helmholtz equation.Neelesh Kumar, Highly Accurate Finite Difference Schemes for the Three-Dimensional Helmholtz Equation, J. Innovation Sciences and Sustainable Technologies, 3(3)(2023), 161 - 181. https://doie.org/10.0904/JISST.2023531643, Email: [email protected]
Uncovering an obscure trade: Threatened freshwater fishes and the aquarium pet markets
No full textWhile the collection of fish for the aquarium pet trade has been flagged as a major threat to wild populations, this link is tenuous for the unregulated wild collection of endemic species because of the lack of quantitative data. In this paper, we examine the extent and magnitude of collection and trade of endemic and threatened freshwater fishes from India for the pet markets, and discuss their conservation implications. Using data on aquarium fishes exported from India, we try to understand nature of the trade in terms of species composition, volume, exit points, and importing countries. Most trade in India is carried out under a generic label of "live aquarium fish"; yet despite this fact, we extracted export data for at least thirty endemic species that are listed as threatened in the IUCN Red List. Of the 1.5 million individual threatened freshwater fish exported, the major share was contributed by three species; Botia striata (Endangered), Carinotetraodon travancoricus (Vulnerable) and the Red Lined Torpedo Barbs (a species complex primarily consisting of Puntius denisonii and Puntius chalakkudiensis, both 'Endangered'). Using the endangered Red Lined Torpedo Barbs as a case study, we demonstrate how existing local regulations on aquarium fish collections and trade are poorly enforced, and are of little conservation value. In spite of the fact that several threatened and conservation concern species are routinely exported, India has yet to frame national legislation on freshwater aquarium trade. Our analysis of the trade in wild caught freshwater fishes from two global biodiversity hotspots provides a first assessment of the trade in endangered and threatened species. We suggest that the unmanaged collections of these endemic species could be a much more severe threat to freshwater biodiversity than hitherto recognized, and present realistic options for management. (C) 2013 Elsevier Ltd. All rights reserved
Drug delivery to the anterior segment of eye
No full textThe human eye’s complex anatomy and protective barriers pose significant challenges for effective drug delivery, with conventional methods like eye drops exhibiting low bioavailability (<5%) and transient therapeutic effects. This chapter examines recent advancements in ocular drug delivery systems designed to overcome these limitations, focusing on minimally invasive strategies for anterior segment disorders. Innovations such as long-acting biodegradable and nonbiodegradable implants (e.g., Ozurdex®, Durysta®) enable sustained drug release, reducing administration frequency and enhancing compliance. Electrospun nanofiber patches and particulate systems (liposomes, nanoparticles) improve corneal penetration and retention, while microneedle technology offers precise, painless delivery of biologics and small molecules. Drug-eluting contact lenses integrate therapeutic release with vision correction, leveraging stimuli-responsive materials for controlled delivery. Despite their promise, challenges persist in scalability, regulatory compliance, and clinical translation. Future directions emphasize smart materials, combination therapies, and personalized approaches to optimize efficacy and safety. Collectively, these technologies represent a paradigm shift in ocular therapeutics, addressing chronic conditions like glaucoma, uveitis, and dry eye syndrome with enhanced bioavailability and reduced patient burden. By bridging gaps between innovation and clinical application, these systems hold transformative potential for improving patient outcomes and quality of life in ocular healthcare.</p
Vision based cognitive fatigue detection
No full textAnalyzing human activity is a basic component of any system, be it biological or artificial, that aims to predict future behavior. Tracking and recognizing voluntary and involuntary action traits are basic endeavors for artificial vision systems that aim to predict cognitive fatigue, a major cause for road and workplace accidents. In this work, we developed a vision system to detect the early onset of fatigue. In collaboration with the Magnetoencephalography Lab at MIT, we collected synchronous brain (Magnetoencephalography - MEG) and behavioral (high-speed camera) data from 13 subjects in a 3-hour task that was designed to induce cognitive exhaustion. We derived a set of 8 eye-movement and 6 head-movement features and trained classifiers(Random Forest, K- Nearest Neighbor, and Support Vector Machine) for two classes (fatigue, non-fatigue) and three classes (fatigue, transition stage, non-fatigue). The models achieved average test accuracies of 98\%, 97\%, 92\% (two classes) and 92\%, 90\%, 87\% (three classes) respectively, for combined features. To further validate our models, we used the alpha band power in the MEG data as the neural indicator of fatigue. A regression analysis between the camera-based features and the alpha band power revealed an average = 0.59 coefficient. Here, we also propose a new method to detect the early stages of fatigue by using the classification error as our behavioral marker. Specifically, we found that the accuracy of the classifiers was higher when the distance between the time intervals of labels for “non-fatigue” and “fatigue” was larger; We estimated the total number of the mis-classified “fatigue” and “non-fatigue” data points in a sliding window: the “fatigue” (“non-fatigue”) number was high (low) in the beginning -non-fatigue stage- and became lower (higher) with time, signifying clear periods of fatigue and non-fatigue. We also observed a sharp change in the labels from non-fatigue to fatigue in the interval of 40-50 minutes, when using a sliding window, which signifies early stages of fatigue. Our results are promising in terms of designing a fully automated system that can predict one’s effective “operation range”, based on behavioral and neurophysiological cues.M.S.Includes bibliographical referencesby Neelesh Kuma
Performance Analysis of Opportunistic Selection and Rate Adaptation in Time Varying Channels
No full textOpportunistic selection and rate adaptation play a vital role in improving the spectral and power efficiency of current multi-node wireless systems. However, time-variations in wireless channels affect the performance of opportunistic selection and rate-adaptation in the following ways. Firstly, the selected node can become sub-optimal by the time data transmission commences. Secondly, the choice of transmission parameters such as rate and power for the selected node become sub-optimal. Lastly, the channel changes during data transmission.
In this thesis, we develop a comprehensive and tractable analytical framework that accurately accounts for these effects. It differs from the extensive existing literature that primarily focuses on time-variations until the data transmission starts. Firstly, we develop a novel concept of a time-invariant effective signal-to-noise ratio (TIESNR), which tractably and accurately captures the time-variations during the data transmission phase with partial channel state information available at the receiver. Secondly, we model the joint distribution of the signal-to-noise ratio at the time of selection and TIESNR during the data transmission using generalized bivariate gamma distribution.
The above analytical steps facilitate the analysis of the outage probability and average packet error rate (PER) for a given modulation and coding scheme and average throughput with rate adaptation. We also present extensive numerical results to verify the accuracy of each step of our approach and show that ignoring the correlated time variations during the data transmission phase can significantly underestimate the outage probability and average PER, whereas it overestimates the average throughput even for packet durations as low as 1 msec
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