Browsing by Author "Selvarajah, P."

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Forecasting the chilli production in Kurunegala district
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Kajanthan, S.; Selvarajah, P.; Mufliha, A.W.F.
In Sri Lanka about 27.1% of its working population is engaged in agriculture, which occupies about 7.54 % of the Gross Domestic Production (GDP). Chilli plays a major role in sustainable agriculture production. However, due to climatic changes, the pattern of chilli production has changed drastically during the past few decades in the Kurunegala district and has severely affected agricultural production. Therefore, this study aims to detect the pattern of the production and forecast and predict the factors impacting on the production during both Yala and Maha seasons from 2001 to 2019. Yearly production of Chilli had been decreasing during Yala and Maha seasons. But, there had been a big change in the production during the Yala season from 2014 to 2017. And also there was a change in the Chilli production level during Maha season from 2013 to 2019. Due to the volatility in the yearly production, a best time series model is selected for forecasting the Chilli production. It was founded that, a best time series model ARIMA (0, 1, 1) fitted for forecasting the Chilli production during the Yala season and ARIMA (0, 1, 2) model fitted for forecasting the chilli production during the Maha season. Moreover, the adequacy of the fitted best model has been tested using Ljung-Box test and Correlation matrix test. Both seasons, the long-term future forecast production values have increased. Another study was carried out to find out the significant factors affecting the productivity of the chilli in both the Yala and Maha seasons. Temperature, rainfall, relative humidity and cloud cover are the significant factors of affecting chilli production. The multiple linear regression analysis shows that temperature, relative humidity and cloud cover have been the significant factors of the chilli production during the Yala Season and the rainfall has been a significant factor of chilli production during Maha season. Kurunegala is categorised under an intermediate zone, therefore all climatic parameters affect a medium level and they help to achieve maximum production of crops that are cultivated in this district.
Validation of root causes for knitting machine downtime
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Fonseka, V. A. C. M.; Jayasinghe, W. J. M. L. P.; Selvarajah, P.; Herath, H. M. N. D.
All machines and machine components are critical and their maintenance is of prime importance in every industrial sector. The halt of a manufacturing process is referred to as the downtime, which may have caused due to a planned or an unplanned event. The main objective of this study was to identify the root causes of knitting machine downtime. There were 178 knitting machines in the knitting section. Those 178 knitting machines were placed in 9 lines whereas each line contains 19 or 20 knitting machines each. Data were collected for a month. This research was based on quality factors including quality control charts and process capability analysis to identify and represent the output of the knitting machine production mainly based on the factors that are related to machine efficiency. The descriptive analysis, one-way ANOVA and the multiple comparison tests were done to the product-wise performance data. Some other analyses were done to find the top contributing reasons that affect the loss of availability in knitting machines. Since there are several types and products and three different teams, the product and team-wise variations were calculated considering availability, performance and quality factors. Out of the many reasons that cause downtime in knitting machines, in this project the stuck of liners in the machine, stuck of main yarn, broken of main yarn, broken of elastic yarn, stoppages occurred due to time taken to replace main yarn, needle run and main machine breakdowns were identified as the main reasons. Further analysis is done by using a fishbone diagram for the root causes for top reasons for machine downtime and liner rejection. The inspections found that most of the quality issues have occurred due to yarns which were not winded up to standard methods and proper conditioning was not done by the relevant employees. The actual liner maturation time is 24 hours. Due to urgent orders, liners are not kept for the maturation purpose. Proper planning should execute to keep the process clean and to give ample time to the employees of the yarn covering section to do their job
Valuation of American put option with transaction cost and dividend using logarithmic front fixing transformation
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Kajanthan, S.; Selvarajah, P.
Due to their early exercise features, American-style options are the most traded in the financial markets. Black-Scholes derive the well-known option pricing Partial Differential Equation (PDE) with some assumptions. Black-Scholes assumes no transaction costs in his option pricing PDE. However, considering transaction costs makes the holder's and writer's option prices not unique, indicating the real-world complexities of trading. This study illustrates the understanding of how transaction costs impact American option pricing. The American-style option pricing problem is a moving boundary problem due to the early exercise feature. The front-fixing transformation technique can be employed to convert a moving boundary problem into a fixed boundary problem. In this work, we used a discrete hedging strategy to derive the option pricing PDEs to evaluate the holder's and writer's option prices and then apply the Logarithmic Front Fixing Transformation (Landau Transformation) to transform them into fixed boundary PDE systems. Then the explicit finite difference scheme is used to obtain numerical solutions. Numerical results confirm that the holder's and writer's option prices are not unique due to the inclusion of the transaction cost. Holders will choose to buy an option at a lower price, in contrast, writers will choose to sell an option at a higher price. The optimal exercise price of the American put option price is higher with transaction costs suggesting that option holders may exercise early to minimize losses, adding practical insight into trading strategies. Additionally, the faster execution time due to the front-fixing technique contributes to more efficient numerical methods in financial modeling.