University of Colombo e-Repository

UCER (University of Colombo Electronic Repository) is a collection of scientific research publications by researchers at the University of Colombo, Sri Lanka. This e-Repository serves to manage, preserve and make available the academic works of the faculty, postgraduate students, and research groups. The collection includes faculty publications, master's and doctoral theses abstracts. This repository is updated regularly, and new works are added to collections on a continuous basis

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Authors are responsible for obtaining copyright permission from the publisher and submitting the signed declaration to ir@lib.cmb.ac.lk.

Recent Submissions

D-REHABIA: A Drug Addiction Recovery Through Mobile Based Application
(Sri Lanka Institute of Information Technology, 2016) Galabada, S.S.G.; Wijethunga, H.M.; Somasiri, L.U.; Dayananda, H.M.; Nugaliyadde, A.; Thelijjagoda, S.; Rajasuriya, M.
Drug addiction has become a major issue in the world. There are certain governmental and nongovernmental organizations which provide variousprograms to prevent, recover and rehabilitate drug addicts. The patients who are in the recovery process havea higher tendency of relapsing after being released to the society. The objective of this research is to produce a mobile based Drug Recovery Application and prevent patients from relapsing during the recovery process and to involve both family and rehabilitation center to the recovery of the patient. In order to accomplish this objective, the application contains an artificial intelligent assistant which will guide/help the patient regarding issues occurred during the recovery process, a location tracking mechanism to identify the movements of the patient and possible high risk places where drugs can circulate, a voice analysis mechanism to analyze the voice of the patient and identify emotional states which might cause the patient to relapse and treatments to reduce the stress, anxiety and depression level of the patient. The field of drug rehabilitation has been barely addressed via a proper technological solution, hence the system implemented as the result of this research can be effectively used for the recovery of the patient.
From Margins to Markets: Digital Inclusion and Economic Opportunities Among Youth with Special Reference to the St. Coombs Tea Estate of Sri Lanka
(University Librarians Association of Sri Lanka, 2025) Alikhan, S.; Kaur, K.; Samsuddin, S.F.
Tea estate communities in Sri Lanka have historically faced systemic marginalization, characterized by limited access to education, infrastructure, and employment opportunities. Within this context, youth experience multiple forms of exclusion and restricted upward mobility. Although digital inclusion is globally recognized as a catalyst for social and economic integration, there remains a limited understanding of how digitally connected youth in Sri Lanka’s tea estates leverage technology for livelihood development. This study addresses this gap by examining how digital inclusion fosters economic opportunities among marginalized youth in one tea estate (St. Coombs tea estate) purposively selected as the research site. The study adopted a qualitative methodology to capture the depth and complexity of participants’ perspectives. Within this framework, a phenomenological research design was employed to explore the lived experiences of youth (ages 15–29) with digital inclusion in the St. Coombs tea estate. Data were collected through 30 in-depth interviews, with 10 participants from this group contributing to photovoice. Data were collected using the snowball sampling technique, which enabled the identification and recruitment of participants through referrals from initial respondents. Gathered data were thematically analyzed using thick description techniques to capture the nuanced role of digital technologies in their everyday economic lives. Findings revealed that digital inclusion has enabled youth to launch home-based businesses, access formal jobs, and enhance self-employment through digital learning. Young women used platforms like Facebook to market cultural skills, while others leveraged YouTube for agricultural innovation and cost-saving techniques. Additionally, many youths engage in digital finance and online marketplaces, increasing financial independence. These practices generate income and shift social status and autonomy within their families and communities. The results underscore how digital access and informal digital learning are key enablers of grassroots economic transformation in excluded regions. Digital inclusion is reshaping economic trajectories in marginalized tea estate communities. It enables agency, innovation, and household contribution among youth. Policymakers and LIS professionals should promote community-based digital literacy initiatives and gender-sensitive interventions to ensure equitable access. Future research should explore gendered digital experiences, inter-regional comparisons, and the role of institutions like libraries and telecentres in fostering digital competencies.
Dynamics of blue carbon in mangroves in the Rekawa Lagoon, Sri Lanka: Integrating remote sensing and the InVEST model for coastal ecosystem management
(University of Colombo, 2025) Suwandhahannadi, W.K.; Wickramasinghe, D.; Dahanayaka, D.D.G.L.; Le De, L.
Coastal blue carbon ecosystems store significant carbon, but are increasingly threatened by land-use changes, habitat degradation, and climate change. By measuring blue carbon, the hidden climate value of mangroves can be recognized, helping to prioritize conservation efforts and develop nature-based solutions that enhance both biodiversity and carbon storage. This study aimed to quantify the spatiotemporal changes of mangrove carbon storage in the Rekawa Lagoon, Sri Lanka, over a two decade period (2001–2021), by integrating Land Use/Land Cover (LULC) maps with the InVEST model (Integrated Valuation of Ecosystem Services and Tradeoffs). Field assessments were conducted to estimate four carbon pools: above-ground biomass, below-ground biomass, soil organic carbon, and dead organic carbon across the sampling sites according to the Blue Carbon Manual. LULC maps for 2001, 2007, 2014, and 2021 were developed using the unsupervised classification technique in ArcGIS 10.6.1 to detect changes in mangrove extent. The recorded mangrove extents were 109, 92, 97, and 100 ha, respectively, in the four years considered. These LULC maps and carbon pool data were then used as inputs in the InVEST model to estimate above-ground, below-ground, soil, and total carbon stocks over a two-decade period. Results indicated that the mangrove extent of the Rekawa Lagoon showed an 8% loss over the study period, with a declining trend (16%) from 2001–2007, and a partial recovery from 2007-2014 (6%) and 2014-2021 (3%). The resulting carbon maps showed notable trends in both carbon sequestration and carbon emissions over the 20 years. The total carbon storage in mangroves was 75,949 MgC in 2001, declining to 63,888 MgC in 2007, followed by a gradual recovery to 67,783 MgC in 2014 and 69,730 MgC in 2021. The initial degradation of carbon stocks may be attributed to settlement expansion, habitat destruction, and the tsunami catastrophe, whereas the observed recovery trend suggests regeneration and conservation efforts. Therefore, the present study highlights the importance of integrating field data, remote sensing, and spatial modelling in assessing blue carbon dynamics. Further, this approach gives a robust scientific basis to develop evidence-based policy, carbon offset planning, and sustainable coastal zone management in Sri Lanka.
Understanding the trace element landscape of Sri Lankan rice: Distribution and correlational patterns of toxic heavy metals and essential elements
(University of Colombo, 2025) Gunawardana, J.W.; Gunawardena, S.A.; Witharana, C.; Wageesha, N.D.A.; Perera, I.C.
Sri Lankan rice is a potential source of nutritionally important essential elements (EEs) and undesirable co-contaminants which include heavy metals (HMs). EEs have an antagonistic response to HMs, by counteracting/detoxifying their effects. Therefore, a higher EE:HM ratio would have more nutritional value. This study investigated and compared cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr) and EEs; zinc (Zn), selenium (Se), manganese (Mn), cobalt (Co) levels in 24 grain composites of commonly consumed rice (Traditional, Improved, Imported) varieties in Sri Lanka. Lyophilized grain powders were digested(in-vitro) and profiled using ICP-MS. The mean (±SD) and median (IQR) of the total HMs and total EEs were; 0.601±0.275, 0.702 (0.411) mg kg-1and 46.545±9.136, 46.968 (13.158) mg kg-1, respectively. The Total-HMs showed a weak positive correlation to Total-EEs (Ʈb=0.101, p>0.05). The distribution of Cd showed positive correlations with all EEs, and with a statistically significant moderate correlation with Mn (Ʈb=0.315, p<0.05). Pb positively correlated with all EEs (p>0.05). However, As positively correlated only with Zn (Ʈb= 0.131, p>0.05) and correlated negatively with Se (Ʈb= -0.136, p>0.05), Mn (Ʈb= -0.116, p>0.05) and Co (Ʈb= -0.004, p>0.05). Cr positively correlated with Zn (Ʈb= 0.171, p>0.05) and Co (Ʈb= 0.298, p<0.05) while negatively correlated with Se and Mn (p>0.05). The EE:HM ratio in the total rice sample ranged from 35.04 to 479.11. The median EE:HM ratio was higher in red pericarp grains compared to white and in parboiled rice than in non – parboiled rice (p>0.05). The EE:HM ratio Traditional rice was ~1.8 times that of both Improved or Imported rice (p>0.05). The median EE:HM ratios in Traditional rice decreased in the order Kaluu-heenati> Pachchaperumal> Suwandel while the ratios from Improved and Imported categories decreased in the order of; Red-kekulu> White-Nadu> Red Nadu> Indian Basmati> Red and White Samba > White Kekulu. The results suggest that despite the overall positive correlation of total-EEs to total-HMs, strategic supplementation of some EEs; Se, Mn could reduce HM accumulation in rice grains. Inclusion of rice varieties with a high EE:HM ratio (i.e. Traditional) in daily dietary habits can help mitigating the exposure to HM by consumers.
Understanding elephant crop raiding behaviour: Interrelations with land use patterns, crop characteristics, and social structure of male elephant
(University of Colombo, 2025) Fernando, C.; Weerakoon, D.; Pilapitiya, S.; Wijesinghe, M.R.; Fernando, P.
The Human–elephant conflict (HEC) is a major conservation challenge in Sri Lanka, driven largely by agricultural expansion into natural habitats, leading to frequent crop raiding. Crop raiding leads to economic losses, threats to farmer safety, negative community attitudes, and results in many elephants being injured or killed each year. Understanding the spatial, ecological, and behavioral drivers is essential to developing effective mitigation strategies. This study examines how landscape features, crop characteristics, and male elephant grouping behaviour influence crop-raiding behavior in Wasgamuwa, Sri Lanka. Between 2018 and 2019, 491 crop-raiding incidents were recorded across 27 Grama Niladhari Divisions (GNDs) in Wasgamuwa. To investigate the factors influencing elephant crop-raiding behavior, a global generalized linear mixed model (GLMM) was constructed using binary crop-raiding data, comparing actual incidents against randomly selected control fields without damage. The model included five spatial variables (distance to electric fence and protected area, other refuge areas, man-made lakes, and home gardens), along with crop type, crop growth stage, and raider group structure (single males vs. male groups). The model was validated, and Akaike Information Criterion (AIC) was used to select the most parsimonious model. The model results revealed that crop raiding was not influenced by proximity to the protected area. However, fields located closer to refuge areas, tanks, and electric fences were associated with a higher risk of raiding. Further, fields situated farther from home gardens were more vulnerable to raids. Crop types strongly influenced raiding likelihood, with paddy fields and home gardens among the most raided, particularly during crop maturity stages. Solitary males primarily raided home gardens, while male groups were more likely to raid paddy fields. These findings highlight the complex interplay of spatial factors, crop characteristics, and the grouping behavior of male elephants in shaping crop-raiding patterns. Effective mitigation requires integrated landscape management and crop protection strategies tailored to field types, crop stages, and the distinct behavior. Such approaches are crucial for fostering coexistence in human-dominated landscapes.