Roshan G Ragel

Prof. Dr. Roshan G Ragel

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

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16 October 2019 in Sensors
Verified
Journal Article
Open access
PDF file
TDTheekshana Dissanayake
Theekshana Dissanayake
YRYasitha Rajapaksha
Yasitha Rajapaksha
RRRoshan G Ragel
Roshan G Ragel
INIsuru Nawinne
Isuru Nawinne
Recently, researchers in the area of biosensor based human emotion recognition have used different types of machine learning models for recognizing human emotions. However, most of them still lack the ability to recognize human emotions with higher classification accuracy incorporating a limited number of bio-sensors. In the domain of machine learning, ensemble learning methods have been successfully applied to solve different types of real-world machine learning problems which require improved classification accuracies. Emphasising on that, this research suggests an ensemble learning approach for developing a machine learning model that can recognize four major human emotions namely: anger; sadness; joy; and pleasure incorporating electrocardiogram (ECG) signals. As feature extraction methods, this analysis combines four ECG signal based techniques, namely: heart rate variability; empirical mode decomposition; with-in beat analysis; and frequency spectrum analysis. The first three feature extraction methods are well-known ECG based feature extraction techniques mentioned in the literature, and the fourth technique is a novel method proposed in this study. The machine learning procedure of this investigation evaluates the performance of a set of well-known ensemble learners for emotion classification and further improves the classification results using feature selection as a prior step to ensemble model training. Compared to the best performing single biosensor based model in the literature, the developed ensemble learner has the accuracy gain of 10.77%. Furthermore, the developed model outperforms most of the multiple biosensor based emotion recognition models with a significantly higher classification accuracy gain.

12 March 2025 in Computers and Electronics in Agriculture
Verified
Journal Article
Open access
RGRomiyal George
Romiyal George
TSThuseethan Selvarajah
Thuseethan Selvarajah
RRRoshan G Ragel
Roshan G Ragel
KMKayathiri Mahendrakumaran
Kayathiri Mahendrakumaran
SNSivaraj Nimishan
Sivaraj Nimishan
MAMamoun Alazab
Mamoun Alazab

4 September 2024 in IEEE Access
Verified
Journal Article
Open access
GDG. A. I. Devindi
G. A. I. Devindi
DDD. M. D. R. Dissanayake
D. M. D. R. Dissanayake
SLS. N. Liyanage
S. N. Liyanage
FFF. B. A. H. Francis
F. B. A. H. Francis
MPM. B. D. Pavithya
M. B. D. Pavithya
INI. Nawinne
I. Nawinne
Oral Squamous Cell Carcinoma (OSCC) poses a significant health challenge, with early detection being crucial for effective treatment and improved survival rates. While previous studies have examined the use of standard photographs, such as those from smartphones, for oral lesion classification, they typically rely solely on images, overlooking the potential benefits of incorporating multiple modalities. This study addresses this gap by proposing a multimodal deep-learning pipeline incorporating diverse data sources, including patient metadata, which mimics the diagnostic approach of clinicians in early detection of oral cancer. The study leverages state-of-the-art image encoders to classify oral lesions into benign and potentially malignant categories. A performance comparison of six pre-trained deep-learning models (MobileNetV3-Large, MixNet-S, ResNet-50, HRNet-W18-C, DenseNet-121, and Inception_v3) is presented. The performance of the proposed pipeline achieved an overall accuracy of 81%, precision of 79%, recall of 79%, F1-score of 78%, and a Matthews Correlation Coefficient (MCC) of 0.57 using the MobileNetV3-Large image encoder. The findings highlight the efficacy of integrating multiple data modalities for more accurate early detection of potential malignancies compared to using only image data. The outcomes could pave the way for improved clinical decision-making and patient outcomes.

29 September 2020 in Communications Biology
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Journal Article
Open access
PDF file
HSHiruna Samarakoon
Hiruna Samarakoon
SPSanoj Punchihewa
Sanoj Punchihewa
ASAnjana Senanayake
Anjana Senanayake
JHJillian M. Hammond
Jillian M. Hammond
ISIgor Stevanovski
Igor Stevanovski
IDIra W. Deveson
Ira W. Deveson
The advent of portable nanopore sequencing devices has enabled DNA and RNA sequencing to be performed in the field or the clinic. However, advances in in situ genomics require parallel development of portable, offline solutions for the computational analysis of sequencing data. Here we introduce Genopo, a mobile toolkit for nanopore sequencing analysis. Genopo compacts popular bioinformatics tools to an Android application, enabling fully portable computation. To demonstrate its utility for in situ genome analysis, we use Genopo to determine the complete genome sequence of the human coronavirus SARS-CoV-2 in nine patient isolates sequenced on a nanopore device, with Genopo executing this workflow in less than 30 min per sample on a range of popular smartphones. We further show how Genopo can be used to profile DNA methylation in a human genome sample, illustrating a flexible, efficient architecture that is suitable to run many popular bioinformatics tools and accommodate small or large genomes. As the first ever smartphone application for nanopore sequencing analysis, Genopo enables the genomics community to harness this cheap, ubiquitous computational resource.

1 August 2012
Verified
Conference Paper
Open access
DHDamayanthi Herath
Damayanthi Herath
CLChathurika Lakmali
Chathurika Lakmali
RRRoshan G Ragel
Roshan G Ragel
Huge amount of data in the form of strings are being handled in bio-computing applications and searching algorithms are quite frequently used in them. Many methods utilizing on both software and hardware are being proposed to accelerate processing of such data. The typical hardware-based acceleration techniques either require special hardware such as generalpurpose graphics processing units (GPGPUs) or need building a new hardware such as an FPGA based design. On the other hard, software-based acceleration techniques are easier since they only require some changes in the software code or the software architecture. Typical software-based techniques make use of computers connected over a network, also known as a network grid to accelerate the processing. In this paper, we test the hypothesis that multi-core architectures should provide better performance in this kind of computation, but still it would depend on the algorithm selected as well as the programming model being utilized. We present the acceleration of a string-searching algorithm on a multi-core CPU via a POSIX thread based implementation. Our implementation on an 8-core processor (that supports 16-threads) resulted in 9x throughput improvement compared to a single thread implementation.

26 July 2024 in Scientific Reports
Verified
Journal Article
Open access
PDF file
IDIsuri Devindi
Isuri Devindi
SLSashini Liyanage
Sashini Liyanage
TJTitus Jayarathna
Titus Jayarathna
JAJanaka Alawatugoda
Janaka Alawatugoda
RRRoshan G Ragel
Roshan G Ragel
Cardiac monitoring systems in Internet of Things (IoT) healthcare, reliant on limited battery and computational capacity, need efficient local processing and wireless transmission for comprehensive analysis. Due to the power-intensive wireless transmission in IoT devices, ECG signal compression is essential to minimize data transfer. This paper presents a real-time, low-complexity algorithm for compressing electrocardiogram (ECG) signals. The algorithm uses just nine arithmetic operations per ECG sample point, generating a hybrid Pulse Width Modulation (PWM) signal storable in a compact 4-bit resolution format. Despite its simplicity, it performs comparably to existing methods in terms of Percentage Root-Mean-Square Difference (PRD) and space-saving while significantly reducing complexity and maintaining robustness against signal noise. It achieves an average Bit Compression Ratio (BCR) of 4 and space savings of 90.4% for ECG signals in the MIT-BIH database, with a PRD of 0.33% and a Quality Score (QS) of 12. The reconstructed signal shows no adverse effects on QRS complex detection and heart rate variability, preserving both the signal amplitude and periodicity. This efficient method for transferring ECG data from wearable devices enables real-time cardiac activity monitoring with reduced data storage requirements. Its versatility suggests potential broader applications, extending to compression of various signal types beyond ECG.