Ravi Sankar

Dr. Ravi Sankar

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Research Focus & Metrics

Academic Career Length

43Years (1984-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 April 2009 in IEEE Computational Intelligence Magazine
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Journal Article
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NSNicholas I. Sapankevych
Nicholas I. Sapankevych
RSRavi Sankar
Ravi Sankar
Time series prediction techniques have been used in many real-world applications such as financial market prediction, electric utility load forecasting , weather and environmental state prediction, and reliability forecasting. The underlying system models and time series data generating processes are generally complex for these applications and the models for these systems are usually not known a priori. Accurate and unbiased estimation of the time series data produced by these systems cannot always be achieved using well known linear techniques, and thus the estimation process requires more advanced time series prediction algorithms. This paper provides a survey of time series prediction applications using a novel machine learning approach: support vector machines (SVM). The underlying motivation for using SVMs is the ability of this methodology to accurately forecast time series data when the underlying system processes are typically nonlinear, non-stationary and not defined a-priori. SVMs have also been proven to outperform other non-linear techniques including neural-network based non-linear prediction techniques such as multi-layer perceptrons.The ultimate goal is to provide the reader with insight into the applications using SVM for time series prediction, to give a brief tutorial on SVMs for time series prediction, to outline some of the advantages and challenges in using SVMs for time series prediction, and to provide a source for the reader to locate books, technical journals, and other online SVM research resources.

17 May 2013 in IEEE Communications Surveys & Tutorials
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Journal Article
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Ismail ButunIsmail Butun
Ismail Butun
SMSalvatore D. Morgera
Salvatore D. Morgera
RSRavi Sankar
Ravi Sankar
Wireless Sensor Networking is one of the most promising technologies that have applications ranging from health care to tactical military. Although Wireless Sensor Networks (WSNs) have appealing features (e.g., low installation cost, unattended network operation), due to the lack of a physical line of defense (i.e., there are no gateways or switches to monitor the information flow), the security of such networks is a big concern, especially for the applications where confidentiality has prime importance. Therefore, in order to operate WSNs in a secure way, any kind of intrusions should be detected before attackers can harm the network (i.e., sensor nodes) and/or information destination (i.e., data sink or base station). In this article, a survey of the state-of-the-art in Intrusion Detection Systems (IDSs) that are proposed for WSNs is presented. Firstly, detailed information about IDSs is provided. Secondly, a brief survey of IDSs proposed for Mobile Ad-Hoc Networks (MANETs) is presented and applicability of those systems to WSNs are discussed. Thirdly, IDSs proposed for WSNs are presented. This is followed by the analysis and comparison of each scheme along with their advantages and disadvantages. Finally, guidelines on IDSs that are potentially applicable to WSNs are provided. Our survey is concluded by highlighting open research issues in the field.

1 March 1996 in Computers in Biology and Medicine
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Journal Article
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TRT.L. Rusch
T.L. Rusch
RSRavi Sankar
Ravi Sankar
JSJ.E. Scharf
J.E. Scharf

1 December 2016 in ICT Express
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Journal Article
Open access
SPShyam V. Perumal
Shyam V. Perumal
RSRavi Sankar
Ravi Sankar
Typically, subjects with Parkinson’s disease (PD) display instances of tremor at an early stage of the disease and later on develop gait impairments and postural instability. In this research, we have investigated the effect of using both gait and tremor features for an early detection and monitoring of PD. Various features were extracted from the data collected from the wearable sensors and further analyzed using statistical analysis and machine learning techniques to find the most significant features that would best distinguish between the two groups: subjects with PD and healthy control subjects. The analysis of our results shows that the features of step distance, stance and swing phases, heel and normalized heel forces contributed more significantly to achieving a better classification between the two groups in comparison with other features. Moreover, the tremor analysis based on the frequency-domain characteristics of the signal including amplitude, power distribution, frequency dispersion, and median frequency was carried out to identify PD tremor from atypical Parkinsonism tremor

1 March 2017 in Biomedical Signal Processing and Control
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Journal Article
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PAPrashanth Chetlur Adithya
Prashanth Chetlur Adithya
RSRavi Sankar
Ravi Sankar
WMWilfrido Alejandro Moreno
Wilfrido Alejandro Moreno
SHStuart Hart
Stuart Hart

18 March 2011 in Journal of Networks
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Journal Article
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XLXuan Hung Le
Xuan Hung Le
MKMurad Khalid
Murad Khalid
RSRavi Sankar
Ravi Sankar
SLSungyoung Lee
Sungyoung Lee
An Efficient Mutual Authentication and Access Control Scheme for Wireless Sensor Networks in Healthcare