International Journal of Advanced Mathematics and Computational Sciences

Estimation of Sun Exposure Duration for Vitamin D Production and Sunburn Risk in Malaysia

Wan Amirul Khusyairi Wan Mohd Roji — 2022-12-25

Ultraviolet radiation is one of the main sources for humans to obtain vitamin D. Although ultraviolet radiation is important for natural vitamin D production, overexposed to ultraviolet radiation and sun's rays at a time can lead to high erythema radiation which cause negative effects on humans. This study aims to measure the dose of solar UV needed to achieve a 1000 IU dose of vitamin D and at the same time produce sunburn in Malaysia. Solar UV erythema radiation measured at three meteorological stations in Malaysia in 2022 to evaluate the effective solar UV radiation resulting in a vitamin D dose of 1000 IU. The duration of daily sun UV exposure is measured in minutes required to produce Vitamin D with a limited risk of sunburn. The total human skin surface exposed to the sun's UV rays is as much as 25.5%, which is the face, arms, hands and neck. In addition, the latitude and longitude of the human position is also a factor that affects the vitamin D obtained because the closer to the Equator, the higher the level of UV radiation. When approaching the Equator, the distance required for sunlight to penetrate the Earth's atmosphere gets closer, causing less absorption of UV rays to occur. Likewise the higher the altitude, the higher the UV radiation. The thin atmosphere at high altitude means that not much UV radiation can be absorbed. With every 1000 m increase in altitude, the level of UV radiation increases by approximately 10%. These findings may explain why vitamin D deficiency is such an important issue in Malaysia. Without additional oral vitamin D, the daily dose required by human of 1000 IU might not be achieved.

The Propagations of Saturating Feedback Mechanism Colorectal Cancer Mathematical Model

Nurul Dayini Zulkifli — 2022-12-25

A mathematical model of colorectal cancer is required to gain a better understanding of the progression of this complex natural process. The mathematical model has provided oncologists with understanding and completing the illness’s behavior. Therefore, this study presents the propagations of cell populations growth saturating and cell populations growth linear and saturating feedback mechanisms colorectal cancer mathematical model. We performed two mechanisms by using Euler’s method to investigate the influence of the growth of cells population colon cancer and to observe the behavior of the kinetics cancer growth as some parameters vary. The first mechanism is saturating mechanism in which we vary parameters , , and . Following that is the linear and saturating mechanism in which we only vary parameters , and . We observed that in saturating feedback mechanism, cell populations growth initiates , and . However, the cell populations growth for linear and saturating mechanism shows , and . Thus, this study shows that the transition of saturating feedback mechanism is faster than the linear and saturating mechanism. It means that the saturating mechanism has the advantage on detection capabilities in tumour growth as the abilities to detect tumour is higher.

Numerical Methods for Non-linear Delay Differential Equations

Harshika Jayamini Abeyrathna — 2022-12-25

The goal of this thesis is to propose the best numerical method for solving non-linear delay differential equations. This work focuses on time-dependent non-linear dynamics in order to investigate. To accomplish this goal, it uses three numerical examples of time-dependent non-linear delay differential equations to solve, adopting three of the most popular numerical methods to compare with each other using MATLAB R2013a. The Adomian decomposition method is an elegant methodology for dealing with a wide range of linear and nonlinear delay differential equations. The iterative decomposition method displays the answers as a quickly convergent infinite series of easily computed terms. The semi-analytical iterative method is a new technique that produces consistent, promising, and powerful outcomes. The data generated by MATLAB is analyzed in three ways: error evaluation, convergent evaluation, and running time evaluation. After considering all three analyses, this study proposes the optimal numerical approach for time-dependent nonlinear delay differential equations. Here, the optimal numerical approach is the Semi-analytical Iterative Method.

Bibliometric Analysis of the Mathematical Learning Method During the Covid-19 Pandemic

Ade Dwi Oktaviani — 2022-12-25

The COVID-19 epidemic has altered many facets of modern life, particularly in the field of education. As a result, all sectors of education must now adapt and continue over the remaining weeks of the semester using a number of alternative teaching strategies. Since it is through education that high-caliber human resources are produced, education plays a critical role in determining the growth and self-realization of individuals, particularly for the development of the nation and state. This study's goal was to evaluate the value of math instruction over a three-year period during the COVID-19 pandemic. Techniques for gathering data by using Google Scholar to search for "Mathematics Learning Methods During the COVID-19 Pandemic" between 2019 and 2022. data analysis utilising the VOS Viewer programme with information from the Publish or Perish programme. The study's findings show that 52 keywords were discovered and classified into 12 clusters. There are 547 authors in the writing network who meet the minimum requirement for authorship networks out of 1.000 authors with a minimum of 3 published publications. The year with the most publications—423—was 2022, according to Google Scholar.

A Mathematical Model to Study the Spread of COVID-19 Pandemic with the Effect of Vaccination

Awansika Nimuthumana — 2022-12-25

At present, vaccines have become the most appropriate preventive measure to combat against COVID-19. In this study, we developed the SIR compartmental model to study the COVID-19 pandemic in Sri Lanka with the effect of vaccination. Our model consists of six compartments, namely SEIRDV which comprises: Susceptible (S), Exposed (E), Infected (I), Recovered (R), Dead (D), and Vaccinated (V). We estimated some key model parameters by fitting the model into the data collected from the official website of the Epidemiological Unit, Ministry of Health, Sri Lanka. Numerical simulations were carried out to investigate the impact of vaccination rate and vaccine inefficacy on population dynamics. Finally, we forecast the future behavior of the pandemic in Sri Lanka. As expected, our findings demonstrated that increasing vaccination rate and decreasing vaccine inefficacy reduce the number of active cases and the number of exposed cases. A 100-day period forecast (from 16th December 2021 to 25th March 2022) demonstrated that there will be 18 COVID-19 active cases and a total of 15430 COVID-19 deaths as of 25th March, 2022 in Sri Lanka. Further forecasts indicated that COVID-19 would disappear from Sri Lanka approximately by July 3rd, 2022.