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Item A Comparative Study of Two-Stage Intrusion Detection Using Modern Machine Learning Approaches on the CSE-CIC-IDS2018 Dataset(MDPI, 2025) Hewapathirana, I. U.Intrusion detection is a critical component of cybersecurity, enabling timely identification and mitigation of network threats. This study proposes a novel two-stage intrusion detection framework using the CSE-CIC-IDS2018 dataset, a comprehensive and realistic benchmark for network traffic analysis. The research explores two distinct approaches: the stacked autoencoder (SAE) approach and the Apache Spark-based (ASpark) approach. Each of these approaches employs a unique feature representation technique. The SAE approach leverages an autoencoder to learn non-linear, data-driven feature representations. In contrast, the ASpark approach uses principal component analysis (PCA) to reduce dimensionality and retain 95% of the data variance. In both approaches, a binary classifier first identifies benign and attack traffic, generating probability scores that are subsequently used as features alongside the reduced feature set to train a multi-class classifier for predicting specific attack types. The results demonstrate that the SAE approach achieves superior accuracy and robustness, particularly for complex attack types such as DoS attacks, including SlowHTTPTest, FTP-BruteForce, and Infilteration. The SAE approach consistently outperforms ASpark in terms of precision, recall, and F1-scores, highlighting its ability to handle overlapping feature spaces effectively. However, the ASpark approach excels in computational efficiency, completing classification tasks significantly faster than SAE, making it suitable for real-time or large-scale applications. Both methods show strong performance for distinct and well-separated attack types, such as DDOS attack-HOIC and SSH-Bruteforce. This research contributes to the field by introducing a balanced and effective two-stage framework, leveraging modern machine learning models and addressing class imbalance through a hybrid resampling strategy. The findings emphasize the complementary nature of the two approaches, suggesting that a combined model could achieve a balance between accuracy and computational efficiency. This work provides valuable insights for designing scalable, high-performance intrusion detection systems in modern network environments.Item Bisphenol-S exposure of zebrafish unveils the hidden risks of bisphenol paradigm with growth, developmental, and behavioral impacts similar to bisphenol-A(Scientific Reports, 2025) Shanika, D.; Rajapaksa, G.The introduction of bisphenol-S (BPS) in substitution of bisphenol-A (BPA) has become argumentative owing to their endocrine destructive properties and insufficient comparative ecotoxicity assessments. Thus, comparative effects of long-term, low-dose BPA and BPS exposure on the development of juvenile zebrafish (Danio rerio) were investigated. Juvenile zebrafish (age: 21 days; weight: ~ 61.5 mg; length: ~ 7.56 mm) were exposed to environmentally-relevant 50 µg/L of BPA, BPS, and control for ~ 60 days in triplicate. Both BPA and BPS significantly increased length (p = 0.00), weight (p = 0.00), specific growth rate (p = 0.00), female preponderance (p = 0.003), mortality (p = 0.017), ammonia excretion (p = 0.00), and aggression (p = 0.00) in zebrafish compared to control. Both bisphenols significantly reduced fish swimming speed in a comparable manner (p = 0.001). A notably higher female-biased-sex ratio was observed in BPS than in BPA (p = 0.003). The length gain (p = 0.014) and aggression (p = 0.032) were higher in BPA-treated fish than in BPS. However, a significant difference was not shown in body mass index (p = 0.295) and condition factor (p = 0.256) between bisphenols and control (p < 0.05). BPA and BPS exposure led to hyperplasia, mucous secretion, aneurism in fish gills, vacuolization and necrosis in liver. Therefore, BPS (~ 50 µg/L) also imposes noteworthy threats to aquatic wildlife, emphasizing the necessity of toxicity assessments and regular monitoring aiming at bespoken environmental standards for freshwater.Item Seaweed-associated fungal endophytes from southern Sri Lanka and their biocontrol potential against selected fungal phytopathogens(Maximum Academic Press, 2025) Abeygunawardane, S.; Thambugala, K.M.; Kumara, W.; Daranagama, D.Fungal endophytes are an endosymbiotic group of fungi that live asymptomatically in healthy tissues of plants and macroalgae. Due to their ability to produce bioactive compounds with potential antifungal properties, fungal endophytes that inhabit seaweed have gained significant attention in the search for sustainable biocontrol agents against phytopathogenic fungi and bacteria. The present study is aimed at identifying fungal endophytes that reside inside seaweeds found in the coastal waters of Southern Province, Sri Lanka, and investigating their biocontrol potential against two fungal phytopathogens; Neopestalotiopsis cubana (Sporocadaceae, Amphisphaeriales) and Colletotrichum siamense (Glomerellaceae, Glomerellales). This is the first study to discover fungal endophytes associated with seaweeds found in the waters of Sri Lanka. Eight fungal endophytic strains were isolated from seaweeds; Padina antillarum (Dictyotaceae), Sargassum ilicifolium (Sargassacea), and Ulva lactuca (Ulvophyceae), found in Thalpe, Madiha, and Koggala beaches. Based on ITS-rDNA sequence analyses, they were preliminarily identified as four distinct endophytic fungal species belonging to the genera Aspergillus and Penicillium. Isolated fungal endophytes were tested for their biocontrol potential against two selected fungal pathogens using a dual culture assay. Percent growth inhibition (PI) of the test pathogens was calculated. Among the isolated fungal endophytes, Aspergillus sp. GMBUCC 24–013 showed the strongest antagonistic activity against both C. siamense UKCC 24-012 and N. cubana GMBUCC 24–001 closely followed by Aspergillus sp. GMBUCC 24–007, GMBUCC 24–008, GMBUCC 24–009, and GMBUCC 24–012. Aspergillus sp. GMBUCC 24–006 exhibited the least biocontrol potential against both phytopathogens, while Penicillium sp. GMBUCC 24–010, and GMBUCC 24–011 showed moderate activity.Item Edge metric dimension of bicyclic graphs(University of Colombo, Sri Lanka, 2025) Gayathrika, K.G.E.H.; Perera, K.K.K.R.Background Slater introduced the ‘metric dimension’(MD) concept in 1975 [4] to provide a framework for uniquely identifying the location of vertices in a connected graph using distances to a specific subset of vertices. In the last decade, this concept has drawn considerable interest from researchers, due to the wide range of applications in computer science, social networks, chemistry, biology, and many others. In 1976, Harary and Melter [5] further investigated the concept and introduced the term ‘resolving set’. The Resolving set is a subset of vertices such that every vertex on the graph can be uniquely identified by its distances to the vertices in this subset, and the MD is the size of the smallest resolving set of that graph. MD has several variants, and ‘edge metric dimension’(EMD) introduced by Kelenc et al. focuses on identifying edges using a minimal resolving set [1]. Notably, this parameter can also be interpreted as the MD of the line graph, where the vertices represent the edges of the original graph and two vertices are connected if they are adjacent in the original graph. EMD is used to design resilient networks and optimize resources in systems. Recently, the EMD of certain families of graphs such as cycles, trees, complete bipartite graphs, trees and circulant graphs has been studied [3]. This study focuses on finding EMD in three types of bicyclic graphs that have not previously been studied. Bicyclic graphs play a vital role in chemical compound analysis, biological networks, and network design etc. Despite significant research on MD, its variant, EMD remained largely unexplored in the context of bicyclic graphs, and the objective here is to fill this research gap. Methods In this paper, graph is represented by G and it’s line graph as L(G). Vertex set v1, v2, ..., vn and edge set e1, e2, ..., en of G is represented by V (G) and E(G) respectively. For simplicity, edge metric dimension of graph G is represented by (dimE (G)). Three types of bicyclic graphs defined in [2] are used in this research. We denote the number of vertices in two cycles by n and m and the length of the path as r. Type I: Cn,m(n, m ≥ 3): Two disjoint cycles sharing a vertex. Type II: Cn,r,m(n, m ≥ 3, r ≥ 1): Two disjoint cycles connected by a path Type III: (θn,n,n(n ≥ 1)): Three pairs of internally disjoint paths, each of length n, were constructed to connect two vertices. Starting from the proper labeling of three types of bicyclic graphs(G) and the corresponding line graphs were constructed (Figures 1 to 4). The EMD is determined analytically and using Python simulations by varying the number of vertices in cycles and paths (n, m, r). Resolving sets (W ) were identified, and vertex sets were partitioned based on their distances to W. A case study demonstrated that all vertices have distinct representations with respect to W, establishing |W| as an upper bound for EMD. Using mathematical proofs, the lower bound was also shown to be equal to |W|, concluding that dimE (G) = |W| for the analyzed graphs. Results and Conclusions The results revealed that all bicyclic graphs have a constant EMD and depend on structural properties, specifically the number of vertices in their cycles and paths. The edge metric dimensions of the type I, II, and III bicyclic graphs are dimE (Cn,m) = 3, dimE (Cn,r,m) = 2, dimE (θn,n,n) = 2, respectively. For a Type I bicyclic graph, the edge metric basis is W = {e1, en, en+m}, for a Type II, W = {e1, en+r+m}, and for a specific case of Type III θ-graphs, W = {e1, en+1}. Having constant EMDs for all bicyclic graphs highlights their efficiency in applications such as resilient network design and molecular modeling. The study contributes to graph theory by addressing a theoretical gap and providing a foundation for exploring metric dimensions in more complex graphs.Item Navigating the age of AI influence: A systematic literature review of trust, engagement, efficacy and ethical concerns of virtual influencers in social media(EnPress, 2024) Hewapathirana I.U.; Perera N.This systematic literature review (SLR) delves into the realm of Artificial Intelligence (AI)-powered virtual influencers (VIs) in social media, examining trust factors, engagement strategies, VI efficacy compared to human influencers, ethical considerations, and future trends. Analyzing 60 academic articles from 2012 to 2024, drawn from reputable databases, the study applies specific inclusion and exclusion criteria. Both automated and manual searches ensure a comprehensive review. Findings reveal a surge in VI research post-2012, primarily in journals, with quantitative methods prevailing. Geographically, research focuses on Europe, Asia Pacific, and North America, indicating gaps in representation from other regions. Key themes highlight trust and engagement’s critical role in VI marketing, navigating the balance between consistency and authenticity. Challenges persist regarding artificiality and accountability, managed through brand alignment and transparent communication. VIs offers advantages, including control and cost efficiencies, yet grapple with authenticity issues, addressed through human-like features. Ethically, VI emergence demands stringent guidelines and industry cooperation to safeguard consumer well-being. Looking ahead, VIs promises transformative storytelling, necessitating vigilance in ethical considerations. This study advocates for continued scholarly inquiry and industry reflection to navigate VI marketing evolution responsibly, shaping the future influencer marketing landscape.Item Spatial variation of water quality in Nilwala river of the Southern Province of Sri Lanka(Ceylon Journal of Science, 2025) Diwyanjalee, G. R.; Premarathne, W. A. P. J.This study addresses the urgent need for comprehensive water quality assessments of the Nilwala River, a vital water source in Sri Lanka’s Matara district, to understand the impacts of anthropogenic activities on regional water resources. The research, conducted over an eight-month period encompassing both dry and wet seasons (March–October 2019), systematically analyzed water samples from eight strategic locations to assess spatial variations in key water quality parameters, including pH, electrical conductivity (EC), temperature, chemical oxygen demand (COD), biological oxygen demand (BOD), alkalinity, hardness, chloride, nitrate, and phosphate. Significant spatial differences were detected in parameters such as pH, EC, COD, BOD, hardness, alkalinity, and chloride (p < 0.001), with COD levels exceeding permissible limits at the Bandaththara power plant and urban Matara, highlighting the influence of industrial and urban discharges. The Weighted Arithmetic Water Quality Index (WAWQI) suggested that most sites require general treatment for drinking water, except Wellathota, which met acceptable standards. Principal Component Analysis (PCA) revealed that alkalinity, chloride, hardness, and COD were the primary contributors to water quality variations, while BOD was negatively correlated with these factors. The analysis identified rural, agricultural, and urban-industrial sites as key areas where water quality is significantly impacted by land use practices, including sand mining, agriculture, and urbanization. The study underscores the necessity for targeted monitoring and management interventions to protect the Nilwala River, emphasizing the importance of implementing mitigation strategies to address pollution sources. The findings provide critical insights into the dynamics of river water quality and highlight the need for sustainable resource management through identifying the pollution hotspots and the factors driving water quality deterioration.Item Diversity and Species Composition of Midgut Symbiotic Bacteria in Culex quinquefasciatus Mosquitoes in Gampaha District, Sri Lanka(Wiley, 2024) Ranasinghe, Koshila; Hathnagoda, Randi; Gunathilake, Pinidi; Buddhinee, Thilini; Welgama, Pabasara; Gunarathna, Hasini; Perera, HarshaniMosquitoes, notorious for their deadly impact as disease vectors, also hold economic value due to their role in disease transmission. This study focuses on understanding mosquito gut microbiota as a foundation for innovative vector control strategies aimed at reducing disease spread. Conducted in the Gampaha Medical Officer of Health (MOH) area in Sri Lanka, the research aimed to explore microbial diversity within the midgut of Culex quinquefasciatus, an essential step to support ongoing paratransgenesis efforts. Sampling was conducted using standard mosquito collection techniques, and bacterial isolates from midgut homogenates were cultured on Plate Count Agar and identified through biochemical testing. The most abundant bacterial families were further analyzed using DNA extraction, PCR amplification, and gene sequencing for species-level identification. The study identified four bacterial families (Staphylococcaceae, Streptococcaceae, Neisseriaceae, and Moraxellaceae) in adult mosquitoes, with an additional family, Micrococcaceae, found in larvae. Notably, the relative distribution of midgut bacteria varied significantly among field-caught larval and adult strains from different study areas (chi-square = 1.673; P < 0.05), suggesting a consistent bacterial flora across mosquito life stages and geographic locations. A key finding was the detection of Lysinibacillus sphaericus, a bacterium with strong potential for use in paratransgenesis. Given the high mosquito density in the region, implementing paratransgenesis for Cx. quinquefasciatus control is recommended. Additionally, understanding gut microbial composition may enhance integration of modified microbiota into existing Sterile Insect Technique (SIT) and Incompatible Insect Technique (IIT) strategies in Sri Lanka.Item Potential of Inhibiting the Receptor Binding Mechanism of SARS-COV-2 using Phytochemicals contained in Paspanguwa Water Extract: Molecular Docking and Dynamic Studies(Asian Journal of Chemistry, 2024-11-30) JAYAWARDENA, P.A.S.N.P.; SOORIYAWANSHA, A.M.S.C.; KUMARATHUNGA, P.G.J.D.; DANANJAYA, P.D.H.; KADIGAMUWA, C.C.; DAHANAYAKE, J.N.This study is focused on the SARS-CoV-2 virus by in silico screening of phytochemicals contained in ‘Paspanguwa’ water extract, targeting ACE2 receptors using molecular docking. Phytochemicals of the five herbal ingredients contained in ‘Paspanguwa’ were extracted into water and were identified based on the literature reviews. Ligands geometries were optimized using Avogadro software and transformed to PDBQT format files by detecting torsion root using AutoDock Tools 1.5.6. SWISS-MODEL server was used to model the structure of the ACE2 receptor based on the UniProt ID Q9BYF1. The stereochemical quality of the protein model was assessed using SAVES v 6.0 and ProSA servers. Finally, potential ligands were docked to the ACE2 receptor protein by considering all variants of this virus and their interactions with the ACE2 receptor. The highest binding energy (BE) (-10.42 kcal/mol) was given by carpesterol phytochemical with allosteric site-2 and allosteric site-3 in the ACE2 receptor and this complex was subjected to molecular dynamic (MD) analysis using a CHARMM36 force field. According to the radius of gyration (Rg), root mean square deviation (RMSD) and root mean square fluctuation (RMSF) results, the studied protein-ligand complex was stable throughout the simulation time.Item Influence of pumpkin seed powder on the characteristic properties of whole wheat cake(Elsevier eBooks, 2024) De, Suprakash; Bharti, D.; Pradhan, B. K.; Behera, H.; Kim, N. M.; Wickramarachchi, S.; Sarkar, P.; Pal, K.Pumpkin seeds are a good source of unsaturated fatty acids, dietary fibers, and minerals. It can be used as a food supplement as the nutritional value of the seeds is relatively high. This study incorporates PSP (pumpkin seed powder) in varying amounts (0%, 5%, 10%, 15%, and 20%) in cake samples. Afterward, their effects on physicochemical, thermal, mechanical, and electrical characteristics were observed. Adding PSP to the cake recipe significantly increased the porosity of the cake by only up to 10% PSP incorporation. The PSP improved the hardness and other textural properties of the cake samples. Also, we can deduce that the water retention capacity of the cake samples increased with the addition of PSP, which increased the moisture content of the cake samples. From the results, we can observe that the browning of the cake increased with the incorporation of PSP in the cake samples. From all the characteristics, we can conclude that the cake sample with 10% PSP had the best texture. This means that PSP can be incorporated into cake samples only up to 10% without compromising the texture and taste.Item Effect of pumpkin seed powder on the properties of cake batter prepared with whole wheat flour(Elsevier eBooks, 2024) De, Suprakash; Bharti, D.; Pradhan, B. K.; Behera, H.; Kim, N. M.; Wickramarachchi, S.; Pal, K.; Sarkar, P.Nutrition plays a crucial role in overall health. Recently, different fruit and vegetable seeds have been incorporated into various food products to increase their nutritional values. Due to its higher nutritional content, the research community has recently explored pumpkin seed powder (PSP) as an ingredient in different bakery products. In the current study the batter composition prepared by whole wheat flour at varying PSP concentrations (5%, 10%, 15%, and 20% w/w) has been studied. The obtained results from the current study suggested that incorporating PSP significantly alters the color, texture, and microstructure of the prepared batter samples. Also, the water retention and air incorporation capacity of the batter samples showed a significant increase after the PSP incorporation. From the 2,2-diphenyl-1-picryl-hydrazyl-hydrate scavenging assay, the antioxidant properties of the prepared batter samples were analyzed. The results suggested an increased antioxidant activity after PSP addition. Though PSP adds to the nutritional value, adding PSP greater than 10% adversely affects the texture of the batters. With 10% of PSP replacement the prepared batter showed a balanced textural property in our study.