Institutional-Repository, University of Moratuwa
Welcome to the University of Moratuwa Digital Repository, which houses postgraduate theses and dissertations, research articles presented at conferences by faculties and departments, university-published journal articles and research publications authored by academic staff. This online repository stores, preserves and distributes the University's scholarly work. This service allows University members to share their research with a larger audience.
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Recent Submissions
item: Thesis-Abstract
Impact of institutional aspects on the adoption of e-procurement in Sri Lankan clothing industry : a case study of Koggala Export Processing Zone
(2024) Dharmasena, MKTW; Edirisinghe, p
A significant portion of Sri Lanka's GDP, more than 7%, comes from the clothing industry, which directly employs 15% of the labour force. One important process that can have a big impact on a company's supply chain performance is procurement. Because of this, procurement errors are frequent in all industries. This is because market demand is not well understood or communicated. Consequently, by using e-procurement, firms will be able to optimize their entire procurement process and reap significant benefits. Therefore, the primary objective of this research is to identify how institutional factors affect the adoption of e-procurement in Sri Lankan clothing industry, with a focus on clothing manufacturers located in the Koggalaaexport processing zone. The systematic literature review was conducted to analyze institution-based factors for the e-procurement adoption. The innovation diffusion theory, technology adoption theory and institutional theory served as the foundation for this investigation. Then the independent variables staff technical competencies, adequate technological infrastructure, managerial commitment, corporate procurement culture, and dependent variable adoption of e-procurement were used to build the conceptual framework. The target population for the research approach was all the workers who are employed in the departments and sub departments which are attached with the procurement process in clothing manufacturers in Sri Lanka's Koggalaaexport processing zone. Convenience sampling was used as the sampling technique. Initially, stepwise regression analysis was conducted, and the results indicated that the changes in the adoption of e-procurement were strongly impacted by only three independent variables: staff technical competencies, adequate technological infrastructure, and managerial commitment. Then due to the invalidity of assumption of homoscedasticity in residual diagnostics, the log transformed regression model was introduced to transform a highly skewed variable into a more normalized dataset. The results reported that the 66.3% of the difference in the adoptionnof e- procurement was clarified through the same institutional factors same as the previous model. Furthermore, this model failed to accept the assumption of homoscedasticity, and three data points were identified as abnormal data points. Then both Cook’s distance test and DFFITS test were conducted separately to calculate values to determine whether these identified abnormal points are influential or not. The thresholder values concluded that the points are not influential data points. However, since these points acted as abnormal points for the data distribution, another regression was conducted without all abnormal data points. Then a more precise model was constructed with the acceptancy of all the residual assumptions. This model showed that the most important institutional determinants for Sri Lankan clothing manufacturers adopting e-procurement are staff technical competencies and adequate technological infrastructure. Additionally, the model showed that institutional variables, staff technical competencies and adequate technological infrastructure account for 63.2% of the variation in e-procurement adoption. Also, it concluded that 36.8% variation in the e – procurement adoption can be encountered by any other factors which are not covered in this study. These results demonstrated that, while transitioning to an electronic-based procurement platform, Sri Lankan textile sector participants must concentrate more on their technological infrastructure, including hardware, software, networking, and communication tool availability. Also, they should hire more skillful employees and should enhance the competency of the working teams to adopt to the new e-procurement platform and work smoothly on that platform
item: Thesis-Abstract
Anomaly detection in time series data
(2024) Niralgama, NGDS; Thalagala, PD
Fraudulent activities have been affecting the world’s day-to-day business, resulting losses over millions to its users. Due to the advancement of technology, fraudsters have many platforms to stay undetected and fraud detection has become critical for organizations and stakeholders such as bankers, investors, credit card users, financial auditors and insurance agents. In addition to detecting fraud, anomaly detections such as diagnosing certain sicknesses, identifying climate change disasters, early warnings on floods and volcano activations are important for many stakeholders. Time series data, in any field can provide significant information when it comes to detecting anomalous activities. Bayesian network, neural network, logistic method, K-nearest neighbor and regression are the most popular data mining approaches in anomaly detection that are being introduced so far. Finding anomalies among time series data is the key approach of detecting fraudulent activities and identifying striking real-world scenarios such as economic recessions. The existing methods and approaches have limitations such as manual thresholds to determine anomaly points, lack of theoretical foundation and lack of attention to class imbalance problem and multivariate data. Approaches such as interquartile rang (IQR) methods assumes that time series data are normally distributed. This assumption does not comply with practical data as they could be positively or negatively skewed. Therefore, to overcome these limitations, this research project introduced a framework to detect anomalies in both univariate and multivariate time series data using extreme value theory. Results of this framework demonstrates that this method’s succeeds identifying the anomalies better than the methods implemented in the two R software packages, anomalize and timetk for detecting anomalies in univariate timeseries data. Further, this framework visualizes the identified anomalies which can be utilized by all stakeholders in for both univariate and multivariate anomalies.
item: Thesis-Abstract
Study on shear strength of root-soil composite for slope stabilization using grass vegetation
(2024) Amali, NPG; Nawagamuwa, UP
Bio-engineering or utilizing plants to reinforce slopes and prevent erosion, for stabilization of both natural and man-made slopes is a cost-effective and sustainable alternative, especially in developing countries like Sri Lanka. Several factors influence the plant roots' ability to increase shear strength. This study investigates influence of Chrysopogon zizanioides (Vetiver grass) roots on soil’s shear strength, focusing on its application in slope stabilization. Shear strength characteristics of soil and soil reinforced with various concentrations of Vetiver grass roots were investigated using large direct shear tests conducted utilizing reconstituted test specimens, to assess their impact on soil shear strength. Stress-strain curves show that, root-reinforced soil exhibit higher shear strength compared to soil-only specimens. Results indicate a proportional increase in shear strength with higher RAR values, with root-permeated soil specimens demonstrating an average shear strength enhancement of approximately 2.5–4 kPa compared to unreinforced specimens, with the increase in RAR up to 1%. The findings suggest that presence of Vetiver roots in soil significantly enhances its shear strength parameters, leading to higher cohesion in root-reinforced soil specimens compared to soil-only specimens. As the RAR increases, indicating a higher density of roots in soil, cohesion of root-reinforced soil specimens also increases proportionally. For the applied normal stress range, observed increase in cohesion of 2 kPa with the increase in RAR up to 1%. Specifically, with a 1% RAR, the study indicates a potential 6% increase in factor of safety, which is a significant improvement of slope stability
item: Thesis-Abstract
Development of a sustainable concrete mix using rice husk ash and steel slag for 3D printing
(2024) Amarasinghe, NA; Gamage, JCPH
Three-dimensional printing has emerged as a transformative technology in the construction industry, offering efficiency and reduced reliance on labour. The automated process of 3D concrete construction, particularly through contour crafting, has minimized labour requirements, eliminated the need for formwork, and garnered acclaim for its sustainability. However, challenges persist, with the choice of proper mix design and materials standing out as a critical factor. This research addresses a significant challenge in 3D concrete technology the excessive use of cement and chemical admixtures. While previous studies have explored partial cement substitution, little attention has been given to replacing fine aggregate. This research focuses on substituting rice husk ash for cement, emphasizing the contribution to bio- concrete by offsetting carbon dioxide emissions. The use of rice husk ash, a well- studied material, aims to enhance workability and flowability.
Furthermore, the study introduces the novel concept of substituting fine aggregate with steel slag, a construction waste material. This collaboration between rice husk ash and steel slag presents a unique challenge due to the irregularities in shape, water absorption properties, and porosity of steel slag. The research aims to analyse the behaviour of 3D concrete in both fresh and hardened states when these two components are combined as partial replacements. The research aims to identify the optimum replacement percentage of steel slag as fine aggregate in 3D concrete, supplemented by a partial substitution of a bio-based cementitious compound. The study explores the rheological behaviour of the fresh concrete, laying the groundwork for future modifications. Objectives include introducing 3D concrete to the Sri Lankan construction industry, replacing fine aggregate with steel slag, employing cost- effective testing methods for rheological properties, and incorporating rice husk ash as a partial replacement for cement.
This research contributes to the sustainable development of 3D concrete technology, offering insights into material substitutions that enhance environmental and economic aspects, making it a valuable endeavour for the construction industry
item: Thesis-Abstract
Formulation of an organic-based liquid fertilizer for hydroponic lettuce
(2023) Jayasinghe, KDPB; Perera, PIP; Manatunge, J
The consumer demand for hydroponically grown leafy vegetables has been rapidly expanding worldwide, among which lettuce is paramount. Consequently, with the escalating usage of inorganic fertilizers, adverse impacts on human health and the environment have been widely recognized. Thus, this study aimed to investigate the effect of organic-based liquid fertilizers (OBLFs) produced using agro-industrial residuals and excretory animal waste on the vegetative growth of Leaf Lettuce (Lactuca sativa L.). The Vermiwash method was employed to produce nine different OBLFs from neem leaves, gliricidia leaves, cow dung, rice husk, goat manure, banana pseudostem, poultry litter, and coconut oil cake whereas the anaerobic fermentation method was employed to produce OBLF from fish waste. The Albert’s solution, a generally utilized chemical liquid fertilizer (CLF) in commercial hydroponics was used as the control. The electrical conductivity (EC), pH, and germination percentage of OBLFs were studied. The Leaf Lettuce was cultivated in a Kratky hydroponic system containing each produced OBLF under the Completely Randomized Design (CRD). Results showed that the range of EC and pH is as follows: EC 1116.3 - 7264.6 S/cm and pH 6.5–9.5. All fertilizers except fish amino acid (FAA) had more than 80 % germination percentage, indicating non-phytotoxic characteristics in OBLFs. The rice husk-derived liquid fertilizer (RH) showed the significantly highest shoot fresh weight (75.2 g), root fresh weight (4.6 g), root dry weight (0.7 g), and maximum root length (43.8 cm) (P<0.05). The goat manure-derived liquid fertilizer (GM) showed the significantly highest shoot length (16 cm), leaf width (16.7 cm), leaf length (19.9 cm), and leaf surface area (332.6 cm2). The highest chlorophyll content was found in the CLF (18.3±4.1a µg/cm2) and RH (17.7±1.0a µg/cm2), (P>0.05). The highest number of leaves and shoot dry weight were found in the CLF (P<0.05). The best vegetative growth was obtained by the RH followed by GM in contrast to the CLF, which could be promisingly utilized in hydroponics for growing lettuce