http://drr.vau.ac.lk/handle/123456789/982 2026-04-05T21:52:37Z 2026-04-05T21:52:37Z Jayasinghe, P.K.S.C. http://drr.vau.ac.lk/handle/123456789/534 2025-03-13T18:27:16Z 0031-08-22T00:00:00Z

Multi-temporal Satellite Images and Combination of Multi-Classification Approaches for Evaluation of Changes in Forest Cover: A case study Jayasinghe, P.K.S.C. The primary objective of this study is to develop a method to monitor the changes in forest cover using three different techniques, namely Spatial Data Mining (SDM), supervised and unsupervised classification, and Geographical Information System (GIS) overlay processing methods. The secondary objective was to monitor the land use changes using multi-temporal satellite images (Landsat 8 images of 2016 and 2020). The study area is located in Nuwara Eliya, Sri Lanka. The first and second approaches consisted of supervised and unsupervised classification approaches. The use of a combination of two classification mapping approaches provides better results compared with the use of a single classification, which is a novelty of the present study. The GIS overly-processing technique combined the two maps obtained from supervised and unsupervised classifications to develop an improved map for land use changes. The improved map was reclassified and converted into ASCII (American Standard Code for Information Interchange) format, which was then pre-processed to convert the data set into the suitable format for the SDM modeling. The converted format was used to implement SDM modeling with the support of the Clustering-outline detection algorithm. The overall accuracy of the Landsat 8 images was 94.6. Results revealed that the forest cover extent was diminished by 5.28% in the study area between 2016 and 2020. The ground measurement was done with the help of the forest department to verify the results. The study revealed that the forest area decreased, and farming lands increased due to intensive agriculture. Future studies would be necessary to determine the validity and suitability of the developed model for other climatic zones in the country.

0031-08-22T00:00:00Z Arumairajan, S. Kayathiri, S. http://drr.vau.ac.lk/handle/123456789/528 2025-03-13T18:27:15Z 0031-08-22T00:00:00Z

A new stochastic restricted two-parameter estimator in multiple linear regression model Arumairajan, S.; Kayathiri, S. In this paper, we proposed a biased estimator, a new stochastic restricted two-parameter estimator (NSRTPE), for the multiple linear regression model to tackle the multicollinearity problem when the stochastic restrictions are available. Necessary and sufficient conditions for the superiority of the proposed estimator over the ordinary least square estimator (OLSE), ridge estimator (RE), Liu estimator (LE), almost unbiased Liu estimator (AULE), modified new two-parameter estimator (MNTPE), mixed estimator (ME), stochastic restricted Liu estimator (SRLE) were derived in the mean square error matrix (MSEM) criterion. Finally, we showed the superiority of the estimator proposed using a simulation study and a real-world example in the scalar mean square error (SMSE) criterion

0031-08-22T00:00:00Z Vijitha, V. Sayanthan, S. Mikunthan, T. http://drr.vau.ac.lk/handle/123456789/527 2025-03-13T18:27:14Z 0031-08-22T00:00:00Z

A Review on Rainwater Harvesting in Sri Lanka Vijitha, V.; Sayanthan, S.; Mikunthan, T. Freshwater scarcity is one of the emerging threats to human survival. There is a gap between availability and demand for freshwater due to urbanization, industrialization, overpopulation, contamination of groundwater, and unpredictable climatic conditions. Rainwater harvesting is an environmentally sound option to mitigate the water scarcity issue. Further, rainwater is a sustainable water source that can be utilized to satisfy the water demand considerably. This manuscript reviews the rainwater harvesting systems in Sri Lanka with particular emphasis on history and present status, different techniques and methods, climate change adaptation, quality and treatments, utilization of harvested water, health benefits and issues, and policy and strategies in the Sri Lankan context. Rainwater harvesting is not a new technology in Sri Lanka; it was even practiced by ancient Sri Lankans many centuries ago. Anyhow, special attention to the operation and maintenance of the rainwater harvesting systems should be paid to improve the quality of harvested water for further uses. In addition, the effectiveness of the policies related to rainwater harvesting should be ensured for the better functioning of rainwater harvesting systems all around the country

0031-08-22T00:00:00Z Paramadevan, P. http://drr.vau.ac.lk/handle/123456789/526 2025-03-13T18:27:15Z 0031-08-22T00:00:00Z

A Binary Integer Programming Approach to find a Sudoku Matrix Paramadevan, P. In the basic Sudoku game, players must fill the entries of a n×n matrix, except some given entries, under the conditions that each row, each column, and each m×m sub-matrix contains integers 1 through n exactly once. In this research paper, in addition to the basic game, conditions and solution process for three advanced versions, such as Sudoku X, Four Square Sudoku and Four Pyramid Sudoku were also studied. In this study, the above-mentioned conditions are converted into appropriate mathematical forms as constraints of the Integer Linear Programming Problem using Pascal Programming Language, such a way that the objective function and the constraints suit as an input mathematical model for the LINGO mathematical optimization software. Here, an unlimited version of the LINGO software has been used with the built-in Branch and Bound algorithm as the number of constraints is very high. Finally, solutions to the given Sudoku problems were obtained from the solutions acquired through LINGO software

0031-08-22T00:00:00Z