International Journal of Learning, Teaching and Educational Research
This study investigated the relationship between the employability of science graduates of a publ... more This study investigated the relationship between the employability of science graduates of a public university in Malaysia and their English language proficiency. Utilising a quantitative research design, the study involved 3,918 graduates from the 2015, 2016 and 2017 graduating years. Using available secondary data, three variables were examined: the graduates’ employment status, their English Language course results, and their Malaysian University Entrance Test (MUET) results. The data was analysed using descriptive statistics, Kolmogorov-Smirnov test and Chi-square test. Findings showed the number of unemployed graduates was consistently greater than employed graduates although the unemployment percentage decreased progressively each year. No conclusive evidence however could be ascertained to suggest English Language proficiency as the main determinant affecting employability since the highest number of employed and unemployed graduates were from the Intermediate and Upper Inter...
The 5TH ISM INTERNATIONAL STATISTICAL CONFERENCE 2021 (ISM-V): Statistics in the Spotlight: Navigating the New Norm
Geographically, there is not much difference between the annual maximum streamflow between neighb... more Geographically, there is not much difference between the annual maximum streamflow between neighbouring sites. Consequently, inter-site dependency should be taken into account for the analysis.The objective of this study is to model the extreme river flow considering the dependence between sites. This study uses an annual maximum river flow () data at five (5) selected stations in Sabah with a sample size of 29 observed from 1988 to 2016. We applied the multivariate extreme value distributions to capture the dependencies of riverflows at neighbouring sites. We build a joint model of the bivariate logistic extreme distribution of the full likelihood function based on the pairwise joint estimation using the composite likelihood approach. The result shows that the bivariate logistics distribution is an appropriate model for the extreme river flow. We also forecast that the return level of the maximum river flow is increasing consistently but is not expected to exceed the maximum level once every 100 years.
The 5TH ISM INTERNATIONAL STATISTICAL CONFERENCE 2021 (ISM-V): Statistics in the Spotlight: Navigating the New Norm
Labour force landscape in Malaysia has grown significantly due to development of the country sinc... more Labour force landscape in Malaysia has grown significantly due to development of the country since the era of independence. The most noticeable change in the aspect of labour force participation is that women's labour force participation is growing not only in Malaysia but also around the world. Rapid developments in the usage of cutting-edge technology, as well as the range of skills that companies demand, have resulted in a more dynamic and competitive workplace. However, the key issue that has not been addressed as the labour market grows is gender wage differential. Various theories and findings have been presented to unravel these issues. In fact, this issue also has a place in high-level forum including United Nation. The wage model is estimated using a pooled model and separate model of gender based on secondary data from the Salaries and Wages Survey, 2018 from Department of Statistics Malaysia. The OLS results suggest that demographic factors, human capital aspects and job characteristics play a significant role in assessing the gender wage difference.
The 5TH ISM INTERNATIONAL STATISTICAL CONFERENCE 2021 (ISM-V): Statistics in the Spotlight: Navigating the New Norm
The objective of this study is to improved inferences for a model of observed extreme data by lin... more The objective of this study is to improved inferences for a model of observed extreme data by linking the distributional of observed data with a climate change model data. We exploit the extra information from projection data of the climate models (RCM and GCM) for the period 1970-2099 under emission scenarios RCP8.5 in modelling an annual extreme rainfall that collected from 44 stations in Sabah. The joint model enables additional information about the trend from longer records of climate model to be incorporated with the limited observed extreme data at each site. The proposed models were built based on the independent likelihood over sites therefore the standard error of the parameters need to be adjusted to take into accounts the inter-site dependence. As a result, we found a common trend between the observed data and climate model and the sandwich estimator reduces the variances of the marginal characteristics and yield more accurate inferences.
The 5TH ISM INTERNATIONAL STATISTICAL CONFERENCE 2021 (ISM-V): Statistics in the Spotlight: Navigating the New Norm
Students' academic success has always been the top priority and is believed to be one of the fact... more Students' academic success has always been the top priority and is believed to be one of the factors that will help in increasing students' employability. Soft skills are also known to be vital before entering the working world. There have been many studies that sought to investigate factors that influence graduate employability. This study aims to determine the impact of academic factors and soft skills on students' employability after they have graduated from university from two main sources, which are the Feedback on the Attributes of UMS Trainee Who Are Currently Undergoing Industrial Training for the year 2017 and the Graduates Tracer Study 2017 administered by the Ministry of Higher Education Malaysia. The population of the study is all the graduates in the year 2017 and a sample of 1028 students was obtained from the respondents that responded to the two matched main sources. Several tests such as the Chi Square test, Independent T-test, and Mann Whitney U test were employed for analyses to determine the relationships and differences between academic factors and soft skills towards graduate employability. The results show that there are no relationships between academic factors, qualification, and program of study. There seem to be a mean difference between academic factors, such as entry and final CGPA, PPIB results and SPM English results towards employability status of graduates. However, as for soft skills (i.e. knowledge, technical skills, ICT skills, problem solving, communication skills, teamwork, leadership, professionalism and ethics), the results show that only ICT skill is statistically significant towards graduate employability.
In recent years, oil palm has grown on a major scale as it is a prominent commodity crop that con... more In recent years, oil palm has grown on a major scale as it is a prominent commodity crop that contributes the most to almost every producing country’s gross domestic product (GDP). Nonetheless, existing threats such as the Ganoderma basal stem rot (BSR) disease have been deteriorating the oil palm plantations and suitable actions to overcome the issue are still being investigated. The BSR disease progression in oil palm is being studied using the disease progression through the plant disease triangle idea. This concept looks at all potential elements that could affect the transmission and development of the disease. The elements include pathogenic, with their mode of infection in each studied factor.
Students are the main assets of universities. Students' academic performance has been the top pri... more Students are the main assets of universities. Students' academic performance has been the top priority for themselves, educators, researchers, government, and parents. There have been many studies that sought to investigate factors that influence students' academic performance and they discover that hard work, discipline, class attendance, self-motivation, previous schooling and family's income affect students' academic performance, and these seem to have significant effects on the students' final Cumulative Grade Point Average, CGPA. This study aims to investigate whether students' English language results and their entry results during admission are also factors that influence their final Cumulative Grade Point Average, CGPA. Multiple linear regression was the analysis used to determine the effect of English proficiency towards students' academic performance. Thus, the results will show the factors that significantly contribute to the students' academic performance.
WSEAS Transactions on Information Science and Applications archive, Jun 1, 2008
The objective of this study was to determine the association between the number of asthmatic pati... more The objective of this study was to determine the association between the number of asthmatic patients in Kota Kinabalu, Sabah with the air quality and meteorological factors using multiple linear regression. Four significant correlation coefficient variables were considered in the multiple linear regression. There were 32 possible models considered together with the related interaction variables and the best model was obtained using the eight selection criteria (8SC). The result showed that the best model obtained could represent the cause of the rise in the number of asthmatics.
The Generalized Extreme Value (GEV) distribution is often used to describe the frequency of occur... more The Generalized Extreme Value (GEV) distribution is often used to describe the frequency of occurrence of extreme rainfall. Modelling the extreme event using the independent Generalized Extreme Value to spatial data fails to account the behaviour of dependency data. However, the wrong statistical assumption by this marginal approach can be adjusted using sandwich estimator. In this paper, we used the conventional method of the marginal fitting of generalized extreme value distribution to the extreme rainfall then corrected the standard error to account for inter-site dependence. We also applied the penalized maximum likelihood to improve the generalized parameter estimations. A case study of annual maximum rainfall from several stations at western Sabah is studied, and the results suggest that the variances were found to be greater than the standard error in the marginal estimation as the inter-site dependence being considered. Key words: Generalized Extreme Value theory, sandwich e...
Labor force demand in Malaysia has grown significantly over the decades since the independence er... more Labor force demand in Malaysia has grown significantly over the decades since the independence era. Changes in economic structure have led to changes in labor force utilization. There are hundreds of studies had been done to investigate the determinants of wages, including human capital factor, demographic factor as well as job characteristic. The objective of this paper is to examine the determinant of wages in Malaysia using the Salaries and Wages Survey, 2016 conducted by the Department of Statistics Malaysia. Based on the analysis of mean differences, the average wage is significantly different for all variables, including age, ethnicity, marital status, education level and occupation. Even in the analysis of the distribution for men and women, the difference in average wage is also identified for each occupation category and sector of the industry.
Introduction: Ambulance response time (ART) has an inseparable relationship with mortality rates ... more Introduction: Ambulance response time (ART) has an inseparable relationship with mortality rates and therefore is important to be reduced. However, an unprecedented increase in road traffic congestion has led to longer ART, especially during peak hours. To reduce ART despite congested traffic, a pre-dispatched ambulance is deployed at hotspot locations during peak hours. This study aims to determine if the hotspot strategy is able to reduce ART in an Urban Emergency Medical Services system.
In large-scale problems, classical Newton's method requires solving a large linear system of equa... more In large-scale problems, classical Newton's method requires solving a large linear system of equations resulting from determining the Newton direction. This process often related as a very complicated process, and it requires a lot of computation (either in time calculation or memory requirement per iteration). Thus to avoid this problem, we proposed an improved way to calculate the Newton direction using an Accelerated Overrelaxation (AOR) point iterative method with two different parameters. To check the performance of our proposed Newton's direction, we used the Newton method with AOR iteration for solving unconstrained optimization problems with its Hessian is in arrowhead form and compared it with a combination of the Newton method with Gauss-Seidel (GS) iteration and the Newton method with Successive Over Relaxation (SOR) iteration. Finally, comparison results show that our proposed technique is significantly more efficient and more reliable than reference methods.
The standard method of the maximum likelihood has poor performance in GEV parameter estimates for... more The standard method of the maximum likelihood has poor performance in GEV parameter estimates for small sample data. This study aims to explore the Generalized Extreme Value (GEV) parameter estimation using several methods focusing on small sample size of an extreme event. We conducted simulation study to illustrate the performance of different methods such as the Maximum Likelihood (MLE), probability weighted moment (PWM) and the penalized likelihood method (PMLE) in estimating the GEV parameters. Based on the simulation results, we then applied the superior method in modelling the annual maximum stream flow in Sabah. The result of the simulation study shows that the PMLE gives better estimate compared to MLE and PMW as it has small bias and root mean square errors, RMSE. For an application, we can then compute the estimate of return level of river flow in Sabah.
It is very crucial to planters to estimate the yield loss due to Ganoderma basal stem rot (BSR) d... more It is very crucial to planters to estimate the yield loss due to Ganoderma basal stem rot (BSR) disease in oil palm. However, currently there is a limited mathematical model available that can be used for that purpose. Therefore, this empirical study was conducted to build a mathematical model which can be used for yield loss estimation due to the disease. Three commercial oil palm plots with different production phases (i.e. steep ascent phase, plateau phase, and declining phase) were selected as the study sites. The yield and disease severity of the selected palms in the three study sites were recorded for the duration of twelve months. Model averaging approach using Bayes theorem was used to build the model. This is also known as Bayesian Model Averaging (BMA). The BMA model revealed that planting preparation technique was the most important predictor of oil palm yield loss, followed by disease progress (measured using area under the disease-progress curve, AUDPC), disease severity, number of infected neighbouring palms, and two interaction terms. By using the developed BMA model, it was estimated that the economic loss can be up to 68% compared to the attainable yields of all the infected palms.
Malaysian Journal of Fundamental and Applied Sciences, 2017
The aim of this study is to model the annual maximum flow of several sites in Sabah with small sa... more The aim of this study is to model the annual maximum flow of several sites in Sabah with small sample sizes using the generalized extreme value (GEV) distribution. Previous studies have shown that the standard method of maximum likelihood estimates would give a poor estimation of the GEV parameters and quantiles for small data set. This study will consider the penalized likelihood estimates as an alternative method to improve the inference over the standard method and retains the modeling flexibility. As comparisons, we will illustrate the results of both methods to model the annual maximum flow in Sabah. The results show the implementation of the penalty function had the same effect to the GEV parameter estimates as suggested by previous studies.
Solving unconstrained optimization problems using Newton method requires calculating Newton's dir... more 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.
Finding the large scale unconstrained minimizer using Newton method has required the calculation ... more 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.
THE 4TH INNOVATION AND ANALYTICS CONFERENCE & EXHIBITION (IACE 2019), 2019
Several methods have been used to estimate the generalized extreme value (GEV) distribution namel... more Several methods have been used to estimate the generalized extreme value (GEV) distribution namely, the standard method of maximum likelihood (MLE) and the probability-weighted moment (PWM). These methods reported having unreliable estimation of parameters when it is involved in a small sample of an extreme event. This could lead to serious effect especially in civil engineering i.e. estimation of extreme streamflow is needed for dam design calculation. As an alternative, penalty function added to MLE to give a better performance of GEV parameter estimation known as the generalized maximum likelihood (GML). The objective of this study is to model the extreme rainfall observed from several stations in Sabah using an approach of the Bayesian analysis. This method is similar to the GML if the information of the penalty function is the same as the prior of the Bayesian. The results from the Markov Chain Monte Carlo with by Metropolis-Hastings the approach can be used to predict the return level of extreme rainfall.
The purpose of this research paper was to compare the marketing mix adopted by two tour operators... more The purpose of this research paper was to compare the marketing mix adopted by two tour operators in Sabah, Malaysia. The marketing mix was defined as the mixture of controllable marketing variables that both tour operators used to pursue the sought level of sales in the tourism and hospitality market. It aimed to provide a better understanding of the four P's (product, price, promotion, and place) in the marketing mix and how they are used in the context of two tour packages. The two tour operators selected for this research paper were Discovery Tours and Wildlife Tours. Findings indicated that few differences exist in the marketing mix of the two tour operators; their product, price, place, and promotions are rather simi lar. Their target markets include both local and overseas and both emphasize adventure and recreation. No differentiation according to age and socioeconomic status is made as both tour operators maintain that their products and services are safe for customers o f all ages and income levels. In general, Wildlife Tours offers more printed information and a better package with a reasonable price for its product, which is the trip to Turtle Islands. To popularize their product as a nature's paradise, they should constantly revise their itineraries to make their package more attractive and affordable, while keeping the carrying capacity optimal. To generate environmental awareness and attract eco-conscious tourists, they should highlight conservation of natural resources in their brochures and websites. They should also mention the age group s, safety measures, and proper use of the natural resources. Both tour agencies should practise market segmentation to attract a particular grou p of consumers, for instance, during the school holidays, they could offer a special package to high school students and teachers. Finally, they should arrange special trips for older persons, the physically challenged, and charity groups.
This study focused on the statistical technique using the factor analysis on constructing the new... more This study focused on the statistical technique using the factor analysis on constructing the new factors affecting students' learning styles of the survey done among university students. In addition, comparison means using the Kruskal-Wallis test were done to analyze the demographic differences on the new factors affecting students' learning styles. The data were collected using survey questionnaires. The number of respondents was 189 students. The methodologies used were descriptive statistics, factor analysis and non-parametric technique using the Kruskal-Wallis test. The results showed seven new factors were successfully constructed using factor analysis and assigned as the factors affecting the learning styles; which are 1) students' attitude before and after attending class, 2) strategies used to comprehend the lecture, 3) the importance of lecture, 4) class size and its condition, 5) efforts outside class, 6) classroom convenient and 7) importance on listening to lecture. The Kruskal-Wallis test results showed there was a significant mean difference between gender on students' efforts outside class (factor 5) while there was no significant mean difference between genders on the other factors of students' learning style. As for years of study, Kruskal-Wallis test showed that students' attitude before and after attending class influenced learning style. The result from Kruskal-Wallis test showed different in score for science and non-science stream students. Non-science students have a better comprehend strategy as their field could be practiced outside classroom and do not merely based on theory. On the other hand, science students satisfy with their class size and its condition as compared to non-science
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Papers by DARMESAH GABDA