Browsing by Author "Abeygunawardhana, P.K.W"

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Development of an Elephant Detection and Repellent System based on Efficient Det-Lite Models
(IEEE, 2023-04-03) Pemasinghe, S; Abeygunawardhana, P.K.W
Human-elephant conflict (HEC) has become a major concern in Sri Lanka that results in many unfortunate human and elephant deaths. Methods that are currently in place to mitigate HEC, such as electrical fences have undesirable consequences resulting in both human and elephant casualties. In this paper, we have proposed a method based on computer vision and deep learning that has a promising potential for detecting and repelling elephants without endangering the lives of elephants or humans. We have used EfficientDet-Lite models that provide a good compromise between accuracy and performance in order to be usable with a resource-constrained device like a Raspberry Pi.
Embargo
Tuning of Optoelectronic Properties of Chalcohalides by Tailoring Pnictogen Composition for Sustainable Photovoltaics
(John Wiley and Sons Inc, 2025-08) Hu, D; Abeygunawardhana, P.K.W; Asha, G
This study investigates Sb1-xBixSeI pnictogen chalcohalides as lead-free materials for photovoltaic and optoelectronic applications using density functional theory (DFT) calculations. Increasing Bi content from 0.5 to 0.6 reduces the bandgap from 1.60 to 1.43 eV, enhancing the light absorption and aligning with the optimal range for solar energy conversions. Structural analysis reveals that higher Bi substitution expands the lattice, reduces the hole effective mass, and improves the hole mobility, while the electron mobility decreases slightly. Sb0.4Bi0.6SeI demonstrates quasi-direct bandgap characteristics attributed to Bi-induced lattice distortion and strong spin–orbit coupling (SOC), which reduces the conduction band minimum and facilitate direct-like electronic transitions. Enhanced absorption near the band edge and localized states contribute to higher sub-bandgap absorption, broadening the spectral response. Reduced bandgap falls within the optimal range for single-junction solar cells, increasing photocurrent generation. While defect-induced recombination poses challenges, passivation and compositional tuning can optimize its performance. This study identifies the potential of Sb0.4Bi0.6SeI as a versatile absorber material in emerging solar cell architectures. The findings provide a pathway toward designing cost-effective and sustainable materials with tailored properties for next-generation photovoltaic and optoelectronic technologies.