Research Papers - Department of Electrical and Electronic Engineering
Permanent URI for this collectionhttps://rda.sliit.lk/handle/123456789/679
Browse
144 results
Filters
Advanced Search
Filter by
Settings
Search Results
Publication Open Access Anthocyanin (ATH)-incorporating polyvinylpyrrolidone-ethyl cellulose-(2-hydroxypropyl)-β-cyclodextrin (PVP–EC–BCD) nanofiber-based pH sensor for ocular pH detection during accidental chemical spills(Royal Society of Chemistry, 2026-02-03) Sandaruwan, B; Liyanage, R; Costha, P; Dassanayake, R.S; Wijesinghe, R.E; Herath H.M.L.P.B; Nalin de S.K.M; de Silva, R.M; Rajapaksha, S.M; Wijenayake, UThe existing ocular pH detection methods encounter numerous limitations, including low accuracy, poor sensitivity across a wide pH range, and patient discomfort, highlighting the need for innovative approaches. A novel biosensor for ocular pH detection has been developed to assess ocular health and chemical injuries in clinical settings. This study uses the pH-sensitive properties of anthocyanins (ATHs), natural pigments extracted from butterfly pea flowers, to develop a novel pH-responsive nanofiber mat. ATHs are integrated into a polymer blend containing polyvinylpyrrolidone (PVP), ethyl cellulose (EC), and (2-hydroxypropyl)-β-cyclodextrin (BCD) to fabricate electrospun nanofibers. The acquired characterization, employing scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), confirmed the successful fabrication of the ATH-infused nanofibers with a mean diameter ranging from 121 to 396 nm. Four formulations were tested: PVP:EC:BCD:ATH (18 ppm), PVP:EC:BCD:ATH (25 ppm), PVP:EC:BCD:ATH (35 ppm), and PVP:EC:BCD:ATH (50 ppm). Among them, the 50 ppm ATH-incorporating nanofiber mat exhibited the best performance in terms of color clarity, response time, and pH sensitivity. The fabricated 50 ppm ATH incorporating nanofiber mat demonstrated a rapid pH response time of less than 5 seconds (s) while exhibiting a color variation from pink to blue to green across the pH range of 1 to 12, providing a rapid and accurate method for visual pH detection. Based on the color performance of the 50 ppm ATH-incorporating system, a standardized color reference chart was developed to serve as a practical and visual guide for estimating pH levels in clinical applications. Zebrafish toxicity assays were conducted further to validate the safety and biocompatibility of the developed sensor, revealing no significant toxic effects across the range of ATH concentrations.Publication Embargo Receiver-Centric Waveform Design: A New Frontier in SWIPT(Institute of Electrical and Electronics Engineers Inc., 2026-01-15) Vithanage, G. S; Jayakody, D. N.K; Krikidis, IIn this work a receiver-centric waveform design technique for simultaneous wireless information and power transfer (SWIPT) is proposed, eliminating the traditional trade-off between energy harvesting (EH) efficiency and information transfer (IT) integrity. By injecting pulses into the receiver, the peak-to-average power ratio (PAPR) of the received signal is increased, using diode nonlinearity to enhance EH without affecting IT. Particle swarm optimization (PSO) is used to tune the pulse parameters to obtain the maximum harvest power under practical constraints. The Monte Carlo simulation results demonstrate superior EH performance compared to existing waveform optimization schemes. The method remains robust under common IT optimizations, such as selective mapping (SLM) and partial transmit sequence (PTS), confirming its compatibility and scalability for real-world SWIPT systems.Publication Open Access Advancing Object Detection: A Narrative Review of Evolving Techniques and Their Navigation Applications(Institute of Electrical and Electronics Engineers Inc., 2025-03-17) Tennekoon, S; Wedasingha, N; Welhenge, A; Abhayasinghe, N; Murray Am, IObject detection plays a pivotal role in advancing computer vision systems by enabling machines to perceive and interact intelligently with their environments. Despite significant advancements, comprehensive exploration of its evolution and applications in navigation remains underrepresented. This review paper examines the evolution of object detection technologies, from early methodologies to contemporary advancements, and their critical role in navigation tasks. The emphasis was on the significance of contextual learning in enhancing object detection performance by leveraging spatial and temporal information. Furthermore, the limitations of conventional approaches that rely heavily on hand-engineered features are examined. It is then demonstrated that contextual learning facilitates automated feature extraction, resulting in improved accuracy exceeding a 50% increase and adaptability in diverse applications. The review concludes by outlining future trends and opportunities for further advancements in object detection and, underscoring its transformative impact on autonomous navigation and beyond. In summary, this review contributes to a comprehensive understanding of object detection technologies by offering insights into their evolution, highlighting their applications in navigation, and providing guidance for future research in context-aware systems.Publication Open Access Three-Dimensional Assessment of Dental Enamel Microcrack Progression After Orthodontic Bracket Debonding Using Optical Coherence Tomography(Multidisciplinary Digital Publishing Institute (MDPI), 2025-01) Saleah, S.A; Hamdan, A.H; Seong, D; Ravichandran, N. K; Wijesinghe, R.E; Han, S; Kim, J; Jeon, M; Park, H. SThe current study aimed to quantify the length progression of enamel microcracks (EMCs) after debonding metal and ceramic brackets, implementing OCT as a diagnostic tool. The secondary objectives included a three-dimensional assessment of EMC width and depth and the formation of new EMCs. OCT imaging was performed on 16 extracted human premolars before bonding and after debonding. Debonding was conducted with a universal Instron machine, with ARI values recorded. Additionally, 2D and 3D OCT images were employed to detect EMC formation and progression. Enface images quantified the length, width, and number of EMCs, and the length and width were analyzed using Image J (1.54f) and MATLAB (R2014b), respectively. Sagittal cross-sectional images were used for EMC depth analysis. A paired t-test showed significant differences in the length, width, and number of EMCs after debonding (p-value < 0.05), while the Wilcoxon non-parametric test indicated significant EMC depth changes (p-value < 0.05). No significant results were identified for the EMC number in ceramic brackets and EMC depth in metal brackets. Three-dimensional OCT imaging monitored existing EMCs at higher risk of progression and detected new EMCs following orthodontic bracket debonding. This study provides novel insights into EMC progression regarding the length, width, depth, and number after debonding.Publication Open Access Next-Gen Decoding: Non-Binary LDPC Algorithms for Emerging Power Line and Visible Light Communications(Institute of Electrical and Electronics Engineers Inc, 2025-06-09) Ullah, W; Yang, F; Choi, K; Jayakody, D.N.KNon-Binary Low-Density Parity-Check (LDPC) codes have gained significant attention due to their remarkable error correction capabilities in various communication systems. Decoding algorithms play a pivotal role in realizing the potential of non-binary LDPC codes. This paper provides a comprehensive review and analysis of non-binary LDPC decoding algorithms, focusing on their efficiency, complexity, and performance. Furthermore, recent advancements and innovations in non-binary LDPC decoding algorithms are discussed, such as improved message passing strategies, layered decoding techniques, and adaptive algorithms. The review also highlights challenges and open research directions in non-binary LDPC decoding, such as mitigating error floors, reducing decoding complexity, and integrating with emerging communication technologies. Finally, the paper draws conclusions on the current state of non-binary LDPC decoding algorithms, underscoring their promising applications in wireless communication, visible light communication (VLC), and power line communication (PLC). Simulation results demonstrate a marked improvement in bit error rate performance for both VLC and PLC systems, highlighting the practical potential of these advanced decoding techniques.Publication Open Access Multi-User Sparse Vector Coding for eXtreme Ultra-Reliable Low-Latency Communication in Beyond 5G(Institute of Electrical and Electronics Engineers Inc., 2025-03-14) Sabapathy, S; Maruthu, S; Jayakody, D. N.KShort A short packet transmission scheme, such as Sparse Vector Coding (SVC), is a primary candidate for achieving ultra-low latency and high-reliability communication (URLLC). This paper proposes a spectral-efficient multi-user SVC (MU-SVC) scheme for achieving next-generation URLLC or eXtreme URLLC (xURLLC) in beyond 5G (B5G) communications. The key idea is to transmit multiple user information within a single sparse vector where the users are segregated into far users (FU) and near users (NU) depending on the distance from the base station. The classification into FU and NU paves way to optimize resource allocation, user fairness, manage interference, ensure reliable communication and quality of service requirements. Firstly, the FU binary data is converted into a sparse vector and secondly, the NU data is modulated and embedded into the non-zero positions of the sparse vector to form an MU-SVC. On transmission, the FU data is obtained through sparse demapping, while the NU adopts symbol detection techniques like the maximum likelihood detector. A new performance metric, called position error rate (PoER), is introduced to study the performance of the FU since it is based on the correct identification of the non-zero positions. Theoretical analyses of PoER and symbol error rate (SER) were carried out for FU and NU, respectively and the results are also validated through Monte-Carlo simulations. Further, the bit error rate, complexity, spectral and latency analyses are performed for MU-SVC and compared with the SVC and enhanced SVC schemes. The simulation results demonstrate an improved spectral efficiency and low latency with high reliability for the proposed MU-SVC scheme, thus, achieving xURLLC with reduced complexity in the multi-user scenario for B5G.Publication Open Access Channel Estimation of full-duplex relay-assisted RSMA-OFDM based wireless networks(Frontiers Media SA, 2025-10-03) Chaudhary, U; Rajkumar, S; Jayakody, D. N.KThis paper analyzes the channel estimation of rate splitting multiple access (RSMA) wireless network through the full-duplex amplify-and-forward (AF) relay. Basically, full-duplex transmission can improve temporal efficiency, however the loop interference is an unavoidable problem that occurs in the strong user of this proposed network. The orthogonal frequency division multiplexing (OFDM) system is used to provide high data rate communication, assuming the presence of phase noise (PN) in local oscillators. Using the least square (LS) estimate, the channel coefficients of the proposed RSMA relay network are estimated. In addition, convex optimization techniques are applied to estimate the phase noise components of this network. The problem is formulated by optimizing phase noise under transmit power constraints. We analyze the Bit Error Rate (BER) performance of the proposed network under binary phase shift keying (BPSK) modulation and 16-quadrature amplitude modulation (QAM). Simulation results demonstrate that channel estimation achieves better performance after the PN compensationPublication Open Access Ambient Backscatter- and Simultaneous Wireless Information and Power Transfer-Enabled Switch for Indoor Internet of Things Systems(Multidisciplinary Digital Publishing Institute (MDPI), 2025-01-06) Sooriarachchi, V.P; Perera, T.D.P; Jayakody, D.N.KIndoor Internet of Things (IoT) is considered as a crucial component of Industry 4.0, enabling devices and machine to communicate and share sensed data leading to increased efficiency, productivity, and automation. Increased energy efficiency is a significant focus within Industry 4.0, as it offers numerous benefits. To support this focus, we developed a hybrid switching mechanism to switch between energy harvesting techniques, ambient backscattering and Simultaneous Wireless Information and Power Transfer (SWIPT), which can be utilized within cooperative communications. To implement the proposed switching mechanism, we consider an indoor warehouse environment, where the moving sensor node transmits sensed data to the fixed relay located on the roof, which is then transmitted to an IoT gateway. The relay is equipped with the proposed switch to energize its communication capabilities while maintaining the expected quality of service at the IoT gateway. Simulation results illustrate the improved energy efficiency within the indoor communication setup while maintaining QoS at varying signal-to-noise (SNR) conditions.Publication Open Access Unleashing the Power of Wireless Communication in Healthcare by Empowering Patient Care and Connectivity: A Comprehensive Survey(Institute of Electrical and Electronics Engineers, 2025-06-10) Chaudhary, U; Furqan A. M; Kumar, A; Sharma, A; Nalin J. D.KThe emergence of the wireless network as a potentially revolutionary innovation has the ability to change the field of medical diagnostics. This in-depth study aims to explore the various aspects of using the latest wireless technologies to improve the standard of care given to patients and the interactions between patients and healthcare providers. This study investigates a wide range of issues such as patient-centric communication technology, 6G based applications using smart technologies, real-time communication protocols, implementation of artificial intelligence (AI) and blockchain technology in healthcare and the use of wireless devices for remote patient monitoring. 6G wireless communication brings transformative capabilities to healthcare, offering ultra-reliable and low-latency communication (URLLC), improved network capacity, and higher data rates. These advances enable the real-time transmission of critical health data, support complex medical applications, facilitate remote consultations, surgical robotics, and AI-driven diagnostics. This study highlights the significance and implications of combining these concepts in the context of 5G and beyond, paving the way for connected healthcare, personalized medicine, and unprecedented levels of efficiency and innovation. In addition, it also investigates the obstacles and potential associated with the implementation of wireless communication in the healthcare industry. These challenges and opportunities include data security and privacy issues, as well as the need for a robust communication infrastructure.Publication Open Access Optimized Resource Allocation for Delay-Tolerant ALOHA–NOMA for Enhancing the Performance of Underwater Acoustic Sensor Networks(Institute of Electrical and Electronics Engineers, 2025-09-22) Goutham, V; Harigovindan V.P; Mahesh, M; Jayakody, D. N.KIn this work, we introduce a propagation delay-tolerant ALOHA–NOMA-based cross-layer protocol for enhancing the performance of Underwater Acoustic Sensor Networks (UASNs). Various phenomena such as multi-path fading, Doppler spread, frequency as well as distance-dependent path loss, and limited available distance-dependent bandwidth have a significant impact on performance of UASNs. Due to these distinct characteristics, ALOHA is often considered a viable medium access control (MAC) protocol for UASNs, even though ALOHA is inefficient as far as channel utilization is concerned. Recently, non-orthogonal multiple access (NOMA) has been envisioned as a thriving enabling technology to meet the burgeoning demands of energy-constrained and bandwidth-constrained UASNs. As a result, we propose propagation delay-tolerant ALOHA-NOMA, where NOMA is employed in the physical layer with optimal utilization of distance-dependent bandwidth and transmission power, to improve the performance of ALOHA-based UASNs. We derive closed-form expressions for the MAC layer utilization factor, goodput, and energy consumption in UASNs by taking into account UASN channel characteristics. Results show that the proposed ALOHA-NOMA scheme significantly improves the performance of UASNs. Finally, we also derive mathematical expressions for the optimal channel attempt rate to maximize the MAC layer utilization factor. The analytical results are validated through extensive ns-3 simulations.