Mahendran ShitanHeriot-Watt University Malaysia · School of Mathematics and Computer Science
Mahendran Shitan
B. Sc. (Hons), M. App. Sc., PhD
About
129
Publications
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Introduction
Mahendran Shitan currently works at Heriot-Watt University Malaysia. His research interest is in Time Series Analysis, Spatial Models and Applied Statistics.
Skills and Expertise
Publications
Publications (129)
In this article, we propose a new model to model the spatial count data
on a two-dimensional regular grid using binomial thinning operator with
dependent Bernoulli counting series. The model is called “first-order spatial
dependent count integer-valued autoregressive (Sp-DCINAR(1,1)) model.”
Some of its properties have been derived and the estimati...
A laboratory prototype system that correlates murine blood absorbance with degree of infection for Plasmodium berghei and Trypanosoma avensi has been designed, constructed and tested. A population (n = 6) of control uninfected, Plasmodium infected and Trypanosoma infected BALB/c mice were developed and spectral absorption measurements pre and post...
Bangladesh is primarily an Agriculture based country and its economy largely depends on the agriculture. Weather and climate are key determinants of the productivity of crops grown in an agrarian country like Bangladesh. Boro rice constitutes a large share in the domestic food grain of the country. Sometimes its production affected by some climatic...
The principal photosynthetic pigment of chlorophyll (chl-a) in the water is produced by phytoplankton and its concentration (CC) is the biomass and abundance indicator of phytoplankton. The small pelagic fishes which feed on phytoplankton is one of the dominant groups caught in Malaysia. The typical challenge in fisheries is to identify a fruitful...
In this paper, we developed a new continuous distribution called the Weibull-Burr type X distribution which extends the Burr type X distribution. We obtained expressions for the density and the cumulative function. We also derived various structural properties of the new distribution are included Quantile function, the moment, moment generating fun...
Some modified non-linear smoothers particularly 4253H[T] are explained in this paper. The modifications are focused on estimating the middle point of running median for even span by applying the following types of means; geometric, harmonic, quadratic and contraharmonic. The performance of the techniques is assessed by applying it to daily price in...
We introduce a new distribution named Exponentiated Generalized Burr type
X (EGBX) distribution with four parameters. This new model can be expressed
as a mixture of Burr type X (BX) distribution with different parameters. Several
sub models are investigated and also some important structure properties of new
model are derived including the quantil...
We introduce a new extension distribution for Burr type X with one parameter named the Beta Burr type X. The new distribution is extended from the Burr type X with one parameter. Several important properties
of the new extension distribution are derived like the moment, and moment generating function. The maximum likelihood estimation is used to es...
Bangladesh is primarily an Agriculture based country and its economy largely depends on theagriculture. Weather and climate are key determinants of the productivity of crops grown inan agrarian country like Bangladesh. Boro rice constitutes a large share in the domestic foodgrain of the country. Sometimes its production affected by some climatic fa...
The main purpose of the study is to propose an algebraic method to obtain the set of all independence models of I × J two-way contingency tables with the same row sums and column sums which is called fiber in algebraic statistics. This method involves solving a system of linear algebraic equations that only rely on row sums and column sums of the I...
Maximum extreme data exist in many fields. The exploration of the extreme data using exploratory data analysis approaches is still considered new although it's being introduced four decades ago by Tukey. In this paper, proposition of some modifications of statistical techniques by Tukey focusing on the resistant line and smoothing line with running...
Ganoderma boninense is a fungus that can affect oil palm trees and cause a serious disease called the basal stem root (BSR). This disease causes the death of more than 80% of oil palm trees midway through their economic life and hexaconazole is one of the particular fungicides that can control this fungus. Hexaconazole can be applied by the soil dr...
The purpose of this study is to project life expectancies (LEs) by sexes and ethnic groups for Malaysia. The secondary data of LE by sex and ethnic groups for Malaysia were extracted from the Department of Statistics, Government of Malaysia. The exponential growth model was employed to fulfill the objective. Projections of LEs for male and female o...
Copula modelling is becoming more popular in modelling dependence multivariate distributions and various copulas have been suggested throughout the literature. In a previous study, we had proposed a new bivariate copula based on Rüschendorf method and had studied some properties of that copula. Therefore, in this paper, we propose an estimator for...
We introduce a new distribution named Exponentiated Kumaraswamy Exponentiated Weibull (EKEW) distribution with six parameters. This new model can be expressed as a mixture of Exponentiated Weibull (EW) distribution density function with different parameters. Several sub models are investigated and also some important structural properties of the ne...
Tukey introduced a resistant smoothing technique which uses running medians but there is a lack of mathematics generalization. Tukey used examples and exhibited an approach in the statistics field called exploratory data analysis. The proposed technique is hereby presented in mathematical equation form and named symmetric running medians. Subsequen...
The main objective of this work is to study Markov bases and toric ideals for
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- contingency tables that has fixed two-dimensional marginal when p is a multiple of v and greater than or equal to 2v. Moreover, the connected bipartite graph is also constructed by using elements of Markov basis. This work is an...
We develop a new continuous distribution called the beta-Burr type X distribution that extends the Burr type X distribution. The properties provide a comprehensive mathematical treatment of this distribution. Further more, various structural properties of the new distribution are derived, that includes moment generating function and the rth moment...
We develop a new continuous distribution called the Gamma-Burr type X (GBX) distribution that extends the Burr type X distribution that has increasing, decreasing and bathtub shapes for the hazard function.Various structural properties of this new distribution are provide, that includes the limit behavior, Quantile function and sub-models. From the...
In this article, we first extend Theorem 2 of Robinson [11] from one dimension to two dimensions. Then the theoretical asymptotic properties of the means, variances, covariance and MSEs of the regression/ GPH (GPH states for Geweke and Porter-Hudak’s) estimators of the memory parameters of the FISSARMA model are established. We also performed simul...
Introduction: There is increasing prevalence of overweight ever-married nonpregnant women while underweight women of the same category remain common. Thus, this study aimed to identify body mass index (BMI) trends as well as the determinants of nutritional status across urban and rural areas and Bangladesh as a whole over the survey years of Bangla...
In this paper, we introduce a new distribution, the Beta Burr type X with one parameter. The new distribution is extended from the Burr type X with one parameter. Various structural properties of the new distribution are derived including moment, and moment generating function. We consider the maximum likelihood estimation to estimate parameters of...
Conference of agricultural statistics (CAS 2015)
Smoking problem is considered as one of the hot topic for many years. In spite of overpowering facts about the dangers, smoking is still a bad habit widely spread and socially accepted. Many people start smoking during their gymnasium period. The discovery of the dangers of smoking gave a warning sign of danger for individuals. There are different...
It is vital to understand the demographic development of the country as demographic changes would affect all areas of human activity. Forecasting demographic variables is important as demographic trends which are neglected could be discovered and new policies can be implemented before situation got worst. A time series model is fitted to forecast t...
Background:
This study is concerned with understanding the impact of demographic changes, socioeconomic inequalities, and the availability of health factors on life expectancy (LE) in the low and lower middle income countries.
Methods:
The cross-country data were collected from 91 countries from the United Nations agencies in 2012. LE is the res...
Random coefficient autoregressive model, RCA(p), has been discussed widely as a suitable model for nonlinear time series. The con- ditional least squares and likelihood parameter estimation of RCA(p) model has also been discussed in [3]. The statistical inference of RCA(1) model has been presented in [4] while the conditional least square es- timat...
Dear Prof. Inoue,
We would like to thank Dr. Selck for his interest in our article, “Relative Importance of Demographic, Socioeconomic and Health Factors on Life Expectancy in Low- and Lower-Middle-Income Countries”.1 We are very grateful to him for his letter2 having scholastic suggestions regarding our study. In that study, an attempt was made t...
In that study, an attempt was made to identify the pathways
by which demographic changes, socioeconomic inequalities,
and availability of health factors influence life expectancy
in low- and lower-middle-income countries (n= 91).
University rankings are becoming a vital performance assessment for higher learning institutions worldwide. Besides the overall rankings, the universities are also ranked by subjects serving as comprehensive guide to discover the specialist strengths of universities worldwide by highlighting top 200 universities for a range of 30 individual popular...
Spatial modeling is important in many fields and there are various kinds of spatial models. One of such models is known as the fractionally integrated separable spatial ARMA (FISSARMA) model. In the area of time series analysis, Sowell (19927.
Sowell, F. (1992). Maximum likelihood estimation of stationary univariate fractionally integrated time ser...
Rice is ranked the third most important crop in Malaysia after rubber and palm oil in terms of production. Unlike the industrial crops, although its contribution to Malaysia’s economy is minimal, it plays a pivotal role in the country’s food security as rice is consumed by almost everyone in Malaysia. Rice production is influenced by factors such a...
Recently, the GARMA(1, 2; δ, 1) time series model has been introduced in the literature. In this paper, the variance and autocovariance of the GARMA(1, 2; δ, 1) model are derived. Some numerical results are also provided. It appears from the simulation study, that the HRA and WE estimation procedures are relatively good for GARMA(1, 2; δ, 1) model....
Objective
To model and forecast hand, foot and mouth disease (HFMD) cases since there has not been any studies on time series modelling of HFMD in Sarawak, Malaysia.
Methods
The longitudinal data of HFMD collected over the past 7 years (2006-2012) showed a cyclical pattern of outbreak every 2 to 3 years. The data consisted of weekly number of HFMD...
River monitoring processes usually generate large databases of water quality variables. These water quality variables are important to identify the status of the river. Due to multidimensionality of complex characteristics in river water, meaningful information from a large database can be extracted by using multivariate statistical methods, i.e.,...
The inability to get people to test regularly and know their Human Immunodeficiency Virus (HIV) status has caused the widespread unavailability of correct and comprehensive data on HIV infection. This study consists of the birth process model for estimating the incidence of HIV infection in three main cities in Bangladesh up to the year 2020. Data...
Six main pollutants have been previously identified by expert opinion to determine river condition in Malaysia. The pollutants were Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Suspended Solid (SS), potential of Hydrogen (pH) and Ammonia (AN). The selected variables together with the respective weights have...
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Demand for urban rail transit and light rail transit (LRT) has increased nowadays especially in developed countries. The purpose of having the LRT is to provide convenience to the public, reduce traffic congestion, reduce parking difficulties, reduce air pollution and so forth. In Malaysia, one of the (Light Rail Transit) LRT routes consists of the...
Some statistical procedures already available in literature are employed in developing the water quality index, WQI. The nature of complexity and interdependency that occur in physical and chemical processes of water could be easier explained if statistical approaches were applied to water quality indexing. The most popular statistical method used...
The top-of-line corrosion (TLC) is corrosion observed at the upper section of a pipeline, as measured from the circumference of the pipe. The magnitude of TLC is mostly determined using the mechanistic condensation models. The spatial prediction of TLC, however, has not been of the interest among researchers, so as to know at what o'clock orientati...
Bangladesh is a developing country and the economic development of the country is mainly based on agriculture which contributes about 20.24% to the Gross Domestic Product. Boro is a variety of rice which is currently accounts for about 57% of total rice production of the country. High Yielding Variety (HYV) was introduced in 1967 and is being culti...
The change in backscattering parameters during the appearance of chilling injury in bananas was investigated. Bananas were stored at a chilling temperature for two days and the degrees of the chilling injuries that appeared were measured before, during and after storage using backscattering imaging and visual assessment. Laser lights at 660 nm and...
Malaysia is a unique country due to having both fixed and moving holidays. These moving holidays may overlap with other fixed holidays and therefore, increase the complexity of the load forecasting activities. The errors due to holidays' effects in the load forecasting are known to be higher than other factors. If these effects can be estimated and...
Malaysia is a unique country due to having both fixed and moving holidays. These moving holidays may overlap with other fixed holidays and therefore, increase the complexity of the load forecasting activities. The errors due to holidays’ effects in the load forecasting are known to be higher than other factors. If these effects can be estimated and...
This study attempts to model the volatility of palm oil price returns via a number of Generalized Autoregressive Conditional Heteroskedasticity class of models that capture the long-range memory, asymmetry, and heavy-tailedness phenomena. These models have been estimated in the presence of four alternative conditional distributions: Gaussian, Stude...
Copula modelling is useful and popular in many areas of statistics like nance, hydrology, drought study, etc. Construction of new copula can be based on Rüschendorf method and in this study, we consctruct a new copula based on a function which consists of the component of exponential functions. We prove that this new copula satises all necessary pr...
Background
We attempted to identify the pathways by which demographic changes, socioeconomic inequalities, and availability of health factors influence life expectancy in low- and lower-middle-income countries.
Methods
Data for 91 countries were obtained from United Nations agencies. The response variable was life expectancy, and the determinant f...
Multivariate data analysis of H-1 Nuclear Magnetic Resonance spectra was applied for the prediction of antioxidant activity in five different Pegaga (C asiatica (var 1), C asiatica (var 2), C asiatica (var 3) H. bonariensis and H. sibthorpioides) varieties. Linear (Partial Least Square regression) and non linear (Artificial Neural Network) models h...
Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) presents a serious healthcare threat to young individuals in Malaysia and worldwide. This study aimed to identify trends in HIV-related risk behaviors among recognized high-risk groups and to estimate HIV transmission up to the year 2015. Data and necessary information wer...
Malaysia experiences two monsoon periods which are usually accompanied by floods and such occurrences have been quite frequent over the past two decades. Muda river which is located in the Northern part of Malaysia has experienced major flood events which are linked to the rainfall duration and severity. Copula modelling has become popular in vario...
All over the world the prevalence of Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS) has became a stumbling stone in progress of human civilization and is a huge concern for people worldwide.
To determine the social and health factors which contribute to increase the size of HIV epidemic globally.
The country level ind...
In this article, we study the properties of the normalized periodogram of the Fractionally
Integrated Separable Spatial ARMA (FISSARMA) models. In particular, we establish
the asymptotic mean of the normalised periodogram and the asymptotic second-order
moments of the normalised Fourier coefficients. We also establish the asymptotic
distribution of...
In this study, three types of Bayesian coincident-index models were designed based on modification from the so-called Stock-Watson (S-W) index, i.e. the established economic coincident-index. The S-W index approach is commonly used to estimate parameters using sufficient time series data in composite index. However, the S-W approach in small time s...
River
Water Quality Index (WQI) is calculated using an aggregation function of the six water quality sub-indices variables, together with their relative importance or weights respectively. The formula is used by the Department of Environment to indicate a general status of the rivers in Malaysia. The six elected water quality variables used in the...
The employment of the fuzzy method to solve differential equations has been well studied. In this article, Mathieu differential equations of the quadrupole mass filter (QMF) have been solved by using the fuzzy method. This method has not been yet investigated in the QMF with fuzzy initial conditions. We survey the physical properties of the confined io...
Generalized Autoregressive (GAR) processes have been considered to model some features in time series. The Whittle's estimates have been investigated for the GAR(1) process by a simulation study by Shitan and Peiris (2008). This article derives approximate theoretical expressions for the enteries of the asymptotic variance-covariance matrix for tho...
Spatial modelling has its applications in many fields. There exist in the literature a class of models known
as the fractionally integrated separable spatial autoregressive (FISSAR) model. In this paper the objective
of our research is to develop a non-separable counterpart of the FISSAR model. We term this model as the
fractionally integrated non-...
Spatial modelling has its applications in many fields. There exist in the literature a class of models known as the fractionally integrated separable spatial autoregressive (FISSAR) model. In this paper the objective of our research is to develop a non-separable counterpart of the FISSAR model. We term this model as the fractionally integrated non-...
Bananas were chilled at 6°C and the appearance of brown spots when exposed to ambient air, a phenomenon known as chilling injury (CI), was detected using computer vision. The system consisted of a digital colour camera for acquiring images, an illumination set-up for uniform lighting, a computer for receiving, storing and displaying of images and s...
Bangladesh is a large agrarian country and the people of Bangladesh mainly depend on rice for their food and calories intake. High Yielding Variety (HYV) Boro rice constitutes a large share in the domestic food grain of the country. HYV Boro rice is cultivated widely in the northern region (Rajshahi division) of Bangladesh. In this study, three dis...
Binomial thinning operator has a major role in modeling one-dimensional integer-valued autoregressive time series models. The purpose of this article is to extend the use of such operator to define a new stationary first-order spatial non negative, integer-valued autoregressive SINAR(1, 1) model. We study some properties of this model like the mean...
Rice is the most important agricultural crop in Bangladesh. The high yielding variety (HYV) Boro rice has the largest share among all the varieties of rice in the country. The yield of HYV Boro rice is strongly interrelated with the climatic and non-climatic factors like rainfall, temperature, humidity, cloud coverage, carbon dioxide emission, wind...
Copepods are the most abundant microcrustaceans in the marine waters and are the major food resource for many commercial fish species. In addition, changes in the distribution and population composition of copepods may also serve as an indicator of global climate changes. Therefore, it is important to model the copepod distribution in different eco...
Ordinary least squares (OLS) and Linear (LIN) estimators are commonly used in estimating the parameters of location-scale family of distributions. Various works have been done to compare the efficiency between these two estimators for the two-parameter exponential distribution and the two-parameter Weibull distribution. Motivated by these works, it...
Bangladesh is an agro-based country and rice is the staple food of the country. Since the independence of the country, food security is mainly dependent on rice production. Rice alone constitutes 92% of the total food grains produced annually in the country. Sustainable food production and achieving food security for the countrymen are the major ch...
A new class of time series models known as generalized autoregressive moving average (1, 1; δ 1 ,δ 2 ) models has been introduced in order to reveal some features of certain time series data. The authors derive the variance and autocovariance of the processes in order to study the behavior of the processes. It is shown that these new results reduce...
Forestry is the art and science of managing forests, tree plantations,
and related natural resources. The main goal of forestry is to create
and implement systems that allow forests to continue a sustainable
provision of environmental supplies and services. Forest area is land
under natural or planted stands of trees, whether productive or not.
For...
Time series data may consists of counts, such as the number of road
accidents, the number of patients in a certain hospital, the number of
customers waiting for service at a certain time and etc. When the value
of the observations are large it is usual to use Gaussian Autoregressive
Moving Average (ARMA) process to model the time series. However if...
In this paper, the Malaysian stock market is analyzed using net-work theory on 782 stocks traded between the period of Jan 2007 to Dec 2010. The correlation networks that capture the price fluctuation pattern during the up trend, and down trend market are constructed. These networks are then characterized with clustering coefficient, maximum size o...
In this paper, the Malaysian Stock Market is studied using the Complex Network notion. We first analyze the statistical properties of eigenvalues of empirical correlation matrix and study the distribution of components of eigenvectors that correspond to certain eigenvalues. We found that the majority of eigenvalues are within the prediction of Rand...
This paper examines inflation volatility estimating a variety of GARCH models with the consideration of the heavy-tailed conditional densities for two post-Soviet transition economies, namely Belarus and Kazakhstan. An EGARCH type model combined with dummies detected from Iterative Cumulative Sum of Squares (ICSS) algorithm, called ICSS-EGARCH, is...
The production of high yielding variety (HYV) Boro rice depends on both climatic variables and some other non-climatic variables. Outliers may occur commonly in agriculture data. Regression outliers either in independent variables or in dependent variables pose a serious threat to traditional least squares analysis. The impact of some climatic and...
In this paper we fit a SARIMA(1,1,0)×(0,1,1) 12 time series model for Bangladesh export values based on the AICC criterion and we found that its forecasting performance is better than the previously proposed SARIMA(4,1,2)×(1,1,0) 12 model by Hossain and Rajeb, 2010.