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Effects of Catheter, Stenosis and Thrombosis in Non-Newtonian Blood Flow Through Narrow Arteries with Clinical Applications: A Mathematical Model

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International Journal of Applied and Computational mathematics 2022年第3期8卷 1-27页

作者： Wajihah, S. Afiqah Sankar, D.S. Nagar, Atulya K. Applied Mathematics and Economics Programme Area School of Applied Sciences and Mathematics Universiti Teknologi Brunei Jalan Tungku Link Bandar Seri Begawan Gadong BE1410 Brunei Darussalam School of Mathematics Computer Science and Engineering Liverpool Hope University Hope Park Liverpool L16 9JD United Kingdom

This study analyses the rheological characteristics of non-Newtonian Carreau fluid model for nanoparticles suspended flow of blood through constricted arteries in the presence of stenosis, thrombosis and catheters. Analytical expressions, such as, velocity distribution, temperature, pressure gradient, wall shear stress and resistive impedance to flow are obtained by implementing the perturbation method and through the extensive use of MATLAB and MATHEMATICA programming tools, the results are presented graphically and tabularly. It is found that temperature of the fluid lessens with the increase in stenosis shape parameter and depth of stenosis which results in the reduction of flow of blood in the artery. It is discovered that a rise in Weissenberg number results in the decrease of fluid’s velocity and skin friction. The magnitude of resistance to blood flow reduces with the upsurge of flow rate and stenosis shape parameter and the reverse character is recognized when Weissenberg number, the depth and axial displacement of blood clot increases. When the angioplasty catheter of radius 0.3 is inserted to the clear the constrictions in the artery, the resistance to flow surges considerably in the range of 6.75–8.78 when the stenosis position extends in the axial direction from 0.1 to 0.3. It is also recorded that when the catheter guidewire radius is 0.18, the pressure gradient in blood flow is found to vary in the range of 1.21–1.43 when the axial variable z varies from 0.2 to 0.8 and it decreases from 1.36 to 1.32 when the blood clot position displaces from 0.2 to 0.6. © 2022, The Author(s), under exclusive licence to Springer Nature India Private Limited.

关键词： Carreau fluid model Catheterization Clinical applications Copper nanoparticles Stenosed artery Thrombosis

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Monitoring the impact of Movement Control Order (MCO) in flattening the cummulative daily cases curve of Covid-19 in Malaysia: A generalized logistic growth modeling approach

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Infectious Disease Modelling 2021年第1期6卷 898-908页

作者： Nicholas Tze Ping Pang Assis Kamu Mohd Amiruddin Mohd Kassim Chong Mun Ho Faculty of Medicine and Health Sciences Universiti Malaysia SabahJalan UMS88400Kota KinabaluSabahMalaysia Mathematics With Economics Programme Faculty of Science and Natural ResourcesUniversiti Malaysia SabahJalan UMS88400Kota KinabaluSabahMalaysia

Introduction:COVID-19 has affected almost every country in the world,which causing many negative implications in terms of education,economy and mental ***,the trend of second or third wave of the pandemic has been noted in multiple regions despite early success of flattening the curve,such as in the case of Malaysia,post Sabah state election in September ***,it is imperative to predict ongoing trend of COVID-19 to assist crucial policymaking in curbing the ***:Generalized logistic growth modelling(GLM)approach was adopted to make prediction of growth of cases according to each state in *** data was obtained from official Ministry of Health Malaysia daily report,starting from 26 September 2020 until 1 January ***:Sabah,Johor,Selangor and Kuala Lumpur are predicted to exceed 10,000 cumulative cases by 2 February ***,the growth factor has been shown to range between 0.25 to a peak of 3.1 throughout the current Movement Control Order(MCO).The growth factor range for Sabah ranged from 1.00 to 1.25,while Selangor,the state which has the highest case,has a mean growth factor ranging from 1.22 to *** highest growth rates reported were inWP Labuan for the time periods of 22 Nov-5 Dec 2020 with growth rates of *** with higher population densities were predicted to have higher cases of ***:GLM is helpful to provide governments and policymakers with accurate and helpful forecasts on magnitude of epidemic and peak *** forecast could assist government in devising short-and long-term plan to tackle the ongoing pandemic.

关键词： COVID-19 Malaysia Generalized logistic growth modelling Forecast

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Grünwald Implicit Solution of One-Dimensional Time-Fractional Parabolic Equations Using HSKSOR Iteration 5

Grünwald Implicit Solution of One-Dimensional Time-Fraction...

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5th International Conference on Mathematical Applications in Engineering 2019

作者： Muhiddin, F.A. Sulaiman, J. Sunarto, A. Faculty of Computer and Mathematical Sciences Universiti Teknologi MARA Cawangan Sabah Malaysia Mathematics with Economics Programme Universiti Malaysia Sabah Malaysia Faculty of Islamic Economics and Business IAIN Bengkulu Indonesia

This paper presents the application of a half-sweep iteration concept to the Grünwald implicit difference schemes with the Kaudd Successive Over-Relaxation (KSOR) iterative method in solving one-dimensional linear time-fractional parabolic equations. The formulation and implementation of the proposed methods are discussed. In order to validate the performance of HSKSOR, comparisons are made with another two iterative methods, full-sweep KSOR (FSKSOR) and Gauss-Seidel (FSGS) iterative methods. Based on the numerical results of three tested examples, it shows that the HSKSOR is superior compared to FSKSOR and FSGS iterative methods. © Published under licence by IOP Publishing Ltd.

关键词： Iterative methods

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Determinants of students’ academic performance among undergraduate students in Universiti Malaysia Sabah: A structural equation modelling approach

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AIP Conference Proceedings 2024年第1期2895卷

作者： Dg Siti Nurisya Sahirah Ag Isha Siti Rahayu Mohd. Hashim Mathematics with Economics Programme Faculty of Science and Natural Resources Universiti Malaysia Sabah 88400 Kota Kinabalu Sabah Malaysia

Any educational institution's success relies on academic performance, increasing interest in discovering factors associated with educational achievement. A greater understanding of this area might help to alleviate the high academic failure rates. This research aimed to identify the factors and determine the indirect effects of these factors on students’ academic performance. Several variables were considered in this study, including students’ emotional intelligence, intelligence, self-esteem, personality trait, and socioeconomic status, such as parental education and household income. The cumulative grade point average was used to assess students' academic performance. This study was conducted at Universiti Malaysia Sabah, and 327 final-year students participated and were selected using the stratified sampling method. Structural equation modeling was employed in order to achieve the objective of this study. Three models were developed and compared in this study. The model has been tested using several fit indices such as the Chi-square (χ²) test, the Comparative Fit Index, the Goodness-of-Fit Index, and the Root Mean Square Error of Approximation. The goodness-of-fit indices suggested that the final model has achieve a good fit model (χ²=24.605, df=19, χ²/df=1.295, CFI=0.993, GFI=0.985, and RMSEA=0.030) as compared to others. The results also revealed that academic performance was directly influenced by self-esteem, IQ, and mothers’ education. Students’ emotional intelligence did not directly affect their academic achievement. Nevertheless, it had a direct influence on IQ and students’ self-esteem. Similarly, the five core personality traits did not directly influence students’ academic performance.

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Newton-2EGSOR Method for Unconstrained Optimization Problems with a Block Diagonal Hessian

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SN Computer Science 2020年第1期1卷 1-11页

作者： Ghazali, Khadizah Sulaiman, Jumat Dasril, Yosza Gabda, Darmesah Faculty of Science and Natural Resources Mathematics with Economics Programme Universiti Malaysia Sabah Kota Kinabalu Sabah 88400 Malaysia Faculty of Electronic and Computer Engineering Universiti Teknikal Malaysia Melaka Melaka 76100 Malaysia

We find that finding the unconstrained optimizer for large-scale problems with the Newton method can be very expensive. Therefore, in this paper, we developed a new efficient method for solving large-scale unconstrained optimization problems with block diagonal Hessian matrices to reduce the cost of computing Newton’s direction. This method is a combination of the Newton method and the 2-point explicit group successive-over relaxation (2EGSOR) block iterative method. To calculate the performance of the developed method, we used a combination of the Newton method with Gauss–Seidel (Newton-GS) point iteration and the Newton method with successive-over relaxation (Newton-SOR) point iteration as reference methods. The numerical experiment has proven that the developed algorithms generate results that are more efficient compared to the reference methods with less execution time and fewer iterations. Through 90 test cases, we observe that the speedup ratio for our proposed method is up to 659.87 times faster compared to the Newton-SOR method and up to 1963.57 times more rapidly than the Newton-GS method. © 2019, Springer Nature Singapore Pte Ltd.

关键词： Explicit group iterative method Large-scale unconstrained optimization problems Newton method

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Business premises workers’ knowledge, attitude and practice towards COVID-19 and its standard operation procedures

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AIP Conference Proceedings 2023年第1期2625卷

作者： Siti Rahayu Mohd. Hashim Farrah Anis Fazliatul Adnan Kamsia Budin Mathematics with Economics Programme Faculty of Science and Natural Resources Universiti Malaysia Sabah 88400 Kota Kinabalu Sabah Malaysia Environmental Science Programme Faculty of Science and Natural Resources Universiti Malaysia Sabah 88400 Kota Kinabalu Sabah Malaysia

Various preventive and precautionary measures have been put in place by the government of Malaysia to safeguard their citizens against COVID-19 whilst allowing economic activities to operate during the pandemic. Business operators and workers must abide by the Standard Operation Procedure (SOP) for Business Premises imposed by the Government of Malaysia in order to prevent the COVID-19 spread. The success of the mitigation measures depend on the business operators’ and their workers’ adherence to the SOP, which is influenced by their knowledge, attitude and practices toward COVID-19 prevention. Therefore, this study was conducted to assess COVID-19 related knowledge, attitude, and preventive practices amongst workers within business premises operating in the districts of Ranau and Kota Kinabalu, Sabah, Malaysia. In addition, this study also aimed to identify the contributing factors to good practices towards COVID19 SOP. Data collection based on convenience sampling was conducted through guided surveys using questionnaires distributed on site within July to September 2020, during which, 147 workers from various food services and grocery business premises participated. A descriptive analysis was carried out to closely investigate any specific pattern in the responses given by the respondents. Spearman's rho correlation test was performed to determine the relationship between knowledge, attitude and practices. Mann-Whitney and Kruskal-Wallis tests were conducted on knowledge, attitude and practice according to demographic factors in order to identify any significant difference toward COVID-19 SOP. Finally, a stepwise multiple regression was performed in order to identify the contributing factors towards good practices of COVID-19 SOP. The results of the analyses revealed that practice and attitude of the respondents were significantly linear moderate positive correlated whereas knowledge and attitude had low positive correlation. There was no statistical evidence of l

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Grünwald Implicit Solution for Solving One-Dimensional Time-Fractional Parabolic Equations Using SOR Iteration 12

Grünwald Implicit Solution for Solving One-Dimensional Time...

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12th Seminar on Science and Technology 2018

The aim of this paper is to examine the effectiveness of Successive Over-Relaxation (SOR) iterative method for solving one-dimensional time-fractional parabolic equations. The Grünwald fractional derivative operator and implicit finite difference scheme have been used to discretize the proposed linear time-fractional equations to construct system of Grünwald implicit approximation equation. The basic formulation and application of the SOR iterative method are also presented. To investigate the effectiveness of the proposed iterative method, numerical experiments and comparison are made based on the iteration numbers, time execution, and maximum absolute error. Based on numerical results, the accuracy of Grünwald implicit solution obtained by proposed iterative method is in excellent agreement, and it can be concluded that the proposed iterative method requires less number of iterations and execution time as compared to the Gauss-Seidel (GS) iterative method. © Published under licence by IOP Publishing Ltd.

关键词： Iterative methods

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A new family of latitudinally corrugated two-spheres of revolution with simple cut locus structure

arXiv

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arXiv 2021年

作者： Tanaka, Minoru Akamatsu, Toyohiro Sinclair, Robert Yamaguchi, Masaru School of Science Department of Mathematics Tokai University Kanagawa Pref Hiratsuka City259–1292 Japan Faculty of Economics Hosei University 4342 Aihara-machi Tokyo Machida194 – 0298 Japan Molecular and Integrative Biosciences Research Programme Faculty of Biological and Environmental Sciences University of Helsinki Finland

There are not so many kinds of surface of revolution whose cut locus structure have been determined, although the cut locus structures of very familiar surfaces of revolution (in Euclidean space) such as ellipsoids, 2-sheeted hyperboloids, paraboloids and tori are now known. Except for tori, the known cut locus structures are very simple, i.e., a single point or an arc. In this article, a new family {Mn}n of 2-spheres of revolution with simple cut locus structure is introduced. This family is also new in the sense that the number of points on each meridian which assume a local minimum or maximum of the Gaussian curvature function on the meridian goes to infinity as n tends to infinity. Thus, our family includes surfaces which have arbitrarily many bands of alternately increasing or decreasing Gaussian curvature, although each member of this family has a simple cut locus *** Codes 53C22 © 2021, CC BY.

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Newton Method with AOR Iteration for Finding Large Scale Unconstrained Minimizer with Tridiagonal Hessian Matrices 9

Newton Method with AOR Iteration for Finding Large Scale Unc...

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2019 9th International Conference on Applied Physics and mathematics, ICAPM 2019

作者： Ghazali, K. Sulaiman, J. Dasril, Y. Gabda, D. Mathematics with Economics Programme Universiti Malaysia Sabah Sabah Kota Kinabalu88400 Malaysia Faculty of Electronic and Computer Engineering Universiti Teknikal Malaysia Melaka Melaka76100 Malaysia

Finding the large scale unconstrained minimizer using Newton method has required the calculation of large and complicated linear systems results from solving the Newton direction. Therefore, in this paper, we propose a method for solving large scale unconstrained optimization problems with tridiagonal Hessian matrices to reduce the complexity of calculating Newton direction. Our proposed method was a combination of Newton method and Accelerated Over Relaxation (AOR) iterative method. To evaluate the performance of the proposed method, combination of Newton method with Gauss-Seidel iteration and Newton method with Successive Over Relaxation (SOR) iteration were used as reference method. Finally, the numerical experiment illustrated that the proposed method produce results that are more efficient compared to the reference methods with less execution time and minimum number of iterations. © Published under licence by IOP Publishing Ltd.

关键词： Newton-Raphson method

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Newton-SOR Iteration for Solving Large-Scale Unconstrained Optimization Problems with an Arrowhead Hessian Matrices 12

Newton-SOR Iteration for Solving Large-Scale Unconstrained O...

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12th Seminar on Science and Technology 2018

Solving unconstrained optimization problems using Newton method requires calculating Newton's direction, which involves inverse Hessian matrices. Once the order of Hessian matrices is large, it may be impossible to store the inverse of the Hessian matrices using the direct method. To overcome this problem, we used a point iterative method as an inner iteration in finding Newton direction. Therefore in this paper, we proposed a combination between Newton method and successive overrelaxation (SOR) point iterative method for solving large scale unconstrained optimization problems in which the Hessian of the Newton direction is arrowhead matrices. To calculate and validate the performance of the proposed method, we used a combination of Newton method with Gauss-Seidel point iteration and Jacobi point iteration scheme as a reference method. The proposed method provides results that are more efficient compared to the reference methods in terms of execution time and a number of iteration. © Published under licence by IOP Publishing Ltd.

关键词： Newton-Raphson method

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