Universiti Putra Malaysia
Download Latest Complete Journal - JST Vol. 24 (2) Jul. 2016
Foreword by the Chief Executive Editor
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Abstract (Viewed: 51)A number of different studies were reviewed to investigate the functionality of splitter plates for the purpose of drag reduction and vortex elimination behind a circular cylinder. The studies were carried out numerically or experimentally in different combinations of Reynolds range, 2D or 3D dimensions, with intention of drag reduction, vortex suppression or both. Results were compared to discover the generalities of a splitter plate's applications and its performance in drag reduction and vortex control. The reduction of 12% up to 38.6% in drag coefficient suggests that all reviewed studies verified the effectiveness of upstream plate in drag reduction. Varied upstream plate's gap ratios (gap between the plate and cylinder) were tested and the optimum position was obtained. For the finite cylinder case, however, the studies discovered that the effectiveness of upstream plate decreased severely and thus, are barely considered as a drag reductive tool for shorter cylinders. Although downstream plate influences drag force, its prominent application is found to be vortex shedding elimination (up to 14.7%). The length ratio and gap ratio of downstream plate were varied in these studies and it was found that the length ratio was a more important factor compared with the gap ratio in the case of vortex suppression.Circular cylinder, Drag reduction, Flow control, Vortex shedding, Vortex suppression, pressure coefficient, Strouhal number, Aspect ratio
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Abstract (Viewed: 7)Reversible logic is one of the rising fields for low-power electronic devices. Testing of these devices is a significant issue where the researchers are at par with the latest innovations in the field. However, new technology gives birth to new challenges, and in this field too, several fault models have arisen. Several online testing methods have been proposed for their detection, which are scaled on various performance parameters. This paper provides a comparative study of online testability for reversible logic. We bring together a review of fault models, performance parameters and online testing strategies from the literature with the aim of obtaining a near optimal solution by efficiently exploring the entire search space. We critically analyze a range of online testing strategies reported by researchers using parity preservation and generation, dual-rail coding and concurrent error detection schemes. These strategies are presented in two broad classifications, namely designing with novel gates and designing with existing circuits. All the techniques are explained in detail with a brief mathematical illustration. A comparison of experimental results based on the available number of benchmarks and combinational logic circuits is presented. The best possible strategy is highlighted on behalf of performance parameters.Reversible logic, online testing, fault models, performance parameters, comparative study
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(Downloads: 107)
Abstract (Viewed: 3)The use of the Light Rail Transit (LRT) system is currently preferred because LRT is sustainable, improves travel options and facilitates swift mobility in urban areas. Hence, the structural stability and safety of this public transportation system against seismic occurrences are indispensable. Given that these structures cannot be considered conventional frames because of their complex architectural design, focussing meticulously on reliable seismic design codes and structural rehabilitation techniques is vital for the design of the lateral resistance system. One Malaysian LRT station is considered in this study, and the seismic response of this train station when equipped with supplementary viscous damper devices is evaluated. Thus, the LRT station is modelled through finite element simulation. The methods of seismic analysis are limited to linear seismic analyses, namely, response spectrum and time history analyses. Results derived in this study show a significant improvement in structural response when the station is fitted with dampers; approximately 40% reduction in displacement is observed at the top joint of the roof. Furthermore, the lateral base shears decrease by approximately 70%.Brace viscous damper, time history analysis, light rail transit, response spectra
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Abstract (Viewed: 2)The study objectives are to verify a path analysis of mental health among Thai elderly with diabetes mellitus. The sampling method used is stratified random sampling. The sample size comprises 2,000 Thai elderly persons over 60 years old with diabetes mellitus. The variables are divided into individual (food, exercise, BMI and drugs), psychological (illness perception) and social factors (family support). Data are analysed using path analysis. The total variables described mental health change by 64.5%. It was found that exercise, illness perception, food and drugs as variables had a direct influence on mental health with standardised regression weights of 0.732, 0.347, 0.243 and 0.050, respectively (p-value<0.01). The exercise variable had a direct effect on mental health the most. The benefits of this study include providing recommendations to guide future mental health policy and to reduce the cost of health maintenance in Thailand.Path analysis, mental health, Thai elderly, Diabetes Mellitus
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Abstract (Viewed: 5)The main challenges of clustering techniques are to tune the initial cluster centres and to avoid the solution being trapped in the local optima. In this paper, a new metaheuristic algorithm, Differential Search (DS), is used to solve these problems. The DS explores the search space of the given dataset to find the near-optimal cluster centres. The cluster centre-based encoding scheme is used to evolve the cluster centres. The proposed DS-based clustering technique is tested over four real-life datasets. The performance of DS-based clustering is compared with four recently developed metaheuristic techniques. The computational results are encouraging and demonstrate that the DS-based clustering provides better values in terms of precision, recall and G-Measure.Data clustering, differential search algorithm, metaheuristic
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Abstract (Viewed: 1)Viscosity, peel strength, shear strength and tack of styrene-butadiene rubber (SBR)-based pressure-sensitive adhesive were studied using silica as the filler. The silica content was varied from 10-50 parts per hundred parts of rubber (phr). The tackifying resin, solvent and coating substrate used were gum rosin, toluene and poly(ethylene terephthalate) (PET) respectively. Viscosity of the adhesive was determined by a Brookfield Viscometer. Both peel strength, shear strength and tack were measured by a Lloyd Adhesion Tester operating at 10-60 cm/min. Results show that viscosity increases with silica loading due to the concentration effect. Peel strength, shear strength and tack passes through a maximum value at 20 phr silica loading, an observation which is attributed to the culmination of wettability at the optimum silica content. Peel strength decreases with the angle of testing at a fixed silica loading and coating thickness. Both peel strength, shear strength and tack increases with coating thickness and testing rates.Adhesion, adhesive, peel, shear, tack, rate of testing
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Abstract (Viewed: 42)The use of an artificial neural network (ANN) is becoming common due to its ability to analyse complex nonlinear events. An ANN has a flexible, convenient and easy mathematical structure to identify the nonlinear relationships between input and output data sets. This capability could efficiently be employed for the different hydrological models such as rainfall-runoff models, which are inherently nonlinear in nature and therefore, representing their physical characteristics is challenging. In this research, ANN modelling is developed with the use of the MATLAB toolbox for predicting river stream flow coming into the Ringlet reservoir in Cameron Highland, Malaysia. A back propagation algorithm is used to train the ANN. The results indicate that the artificial neural network is a powerful tool in modelling rainfall-runoff. The obtained results could help the water resource managers to operate the reservoir properly in the case of extreme events such as flooding and drought.Artificial neural networks, back propagation algorithm, rainfall-runoff modelling
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Abstract (Viewed: 1)Sorting huge data requires an enormous amount of time. The time needed for this task can be minimised using parallel processing devices like GPU. The odd-even transposition sorting network algorithm is based on the idea that each level uses an equal number of comparators to arrange data. The existing parallel OETSN algorithm compares the elements in each phase for any type of test case. If the elements are not in the increasing order, then they are swapped. In this way, the algorithm takes the same time for sorting and for unique test cases. In this paper, we propose an algorithm that is the modified version of the existing OETSN algorithm. Our approach reduces the number of levels in the OETSN based on the nature of the data. Time complexity is also reduced from O(n) to O(1) for sorted and zero test cases. The proposed algorithm is tested for six types of test case, which are uniform, Gaussian, zero, bucket, staggered and sorted. The comparison with existing techniques is also presented in this paper. After evaluation, the proposed modified version of OETSN is found to be more efficient in two types of test case i.e. sorted and zero test cases. GPU computing using CUDA hardware is used to test the algorithms. The speedup achieved by the parallel OETSN algorithm over sequential OETSN is also computed. The proposed approach achieves an improvement in execution time that is 981661.6 times faster in the sorted test case and 904620.7 times faster in the zero test case using 2500000 elements and 1024 threads in comparison to the existing parallel OETSN.Sorting, GPU computing, CUDA, comparators, OETSN
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Abstract (Viewed: 9)Human breast milk microbiota is essential for infant immune system development, maturation and protection against infection. However, there is scarce information on the fluid's microbiological composition from Malaysia. The objective of the study was to isolate, identify and characterise commensal bacterial population present in human breast milk from Malaysia. One hundred bacteria were isolated from the human breast milk of healthy lactating women (n=30). After preliminary screening, 20 isolates were characterised using both phenotypic and molecular techniques. The results indicated that most frequently identified bacteria in this study were E. faecalis and S. hominis. These organisms alongside E. cloacae were all metabolised D-Maltose, Sucrose, D-Turanose, alpha-D-Glucose, D-Fructose, D-Mannose, D-Galactose, D-sorbitol and D-Mannitol and were able to grow at pH 5 and 6, 1% sodium lactate, 1%, 2% and 8% NaCl. BLAST showed over 99% similarity to those deposited in Genbank. Phylogenetic-relatedness was depicted using neighbour-joining method and had two clades with 100% bootstrap. These findings provided insight into the nature, characteristics and also phylogenetic-relatedness of bacteria present in human milk from Malaysia. Isolation and identification of commensal bacteria from human milk are considered the first step for future studies on the benefit of these organisms towards human health.Commensal bacteria, human breast milk, Malaysia, phenotype, phylogeny
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Abstract (Viewed: 1)Multipath transmission of raw sensor signals is the customary technique used in the wireless sensor network to improve end-to-end delivery. However, this technique suffers significantly because of the occurrence of multiple copies of data at the destination and their collision. The Collision-Free Nearest Neighbour Assertion (CNNA) method with n-d tree structure improves the collision removal which, in turn, avoids duplicate packets, but load balancing among neighbouring nodes is an essential issue. Optimising network performance by considering various network parameters and load balancing the network demands a good evolutionary-based optimisation technique other than traditional algorithms. Optimisation techniques based on Particle Swarm Optimisation (PSO) and Genetic Algorithm (GA) are applied and compared against various network parameters in this work.Collision-Free Nearest Neighbour Assertion (CNNA), genetic algorithm (GA), multipath transmission, Particle Swarm Optimisation (PSO).
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Abstract (Viewed: 2)Energy is a main issue in wireless sensor networks (WSN) that function on limited power supplies like batteries. Minimisation of energy utilisation is a promising area of research in WSN. However, energy utilisation of partitioning data still remains a demanding issue. With the objective of reducing the energy utilisation partitioning multi-hop wireless communications, the Energy-Efficient Traffic Renovate Partitioning (EETRP) method is proposed in this paper. The network traffic partitioning method, phantom partitioning, is an efficient technique for practical conditions. The partitioning using double cut methods yields desirable results with significant reduction in energy utilisation. Renovating by the EETRP method provides enhanced data gathering by means of centroid mean point gathering. Crucial sites are recognised and connectivity is reestablished in data aggregation. The results prove that the EETRP method achieves significant improvement in performance over state-of-the-art methods in terms of network-connectivity rate, data-gathering accuracy, network-traffic rate, energy-utilisation rate, node-renovating efficiency and network-partitioning time.Energy-efficient traffic renovate partitioning, partition gaps, phantom partitioning, wireless sensor networks
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Abstract (Viewed: 3)Colo-colic intussusception is a rare manifestation of a primary tumour in an adult patient. This article aims to document the rarity of colo-colic intussusception features on the 18 FDG- PET-CT in a patient with primary colonic carcinoma. An 18 FDG-PET-CT was performed for the purpose of pretreatment staging of a colonic carcinoma in a 61-year-old man following a diagnostic colosnoscopic biopsy. He presented with abdominal distension and peri-rectal bleeding for a month. The fused 18 F-FDG PET-CT image revealed an FDG-avid mass in the left hemicolon showing a rim of FDG avidity denoting the head of intussusceptum. There are also multiple FDG-avid nodules seen along the anti-mesenteric colonic fat suspicious for lymph nodes metastasis. Debulking of tumour revealed a mucinous adenocarcinoma of colon with a metastatic lymph node. 18 FDG PET-CT features of intussusception in colonic carcinoma have never been described before. It can potentially become a preferred diagnostic tool in delineating a potential tumour mass within the intussusceptions that help improve prognosis in patients with malignancyColonic carcinoma, synchronous tumour, adult intussusception, colo-colonic intussusceptions, FDG PET-CT
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Abstract (Viewed: )The presence of calcification in a particular FDG-avid soft tissue lesion may at times present uncertainty regarding the clinical course of the disease pathology. Calcific deposits are not specific for either benign or malignant aetiologies (Brant et al., 2010). Altered glucose metabolism with associated calcification may underpin underlying aggressive pathophysiology with necrosis as sequelae. Mantle Cell Lymphoma (MCL) is a subtype of non-Hodgkin's lymphoma. It is a rare B-cell NHL that is prevalent in men over the age of 60. The disease may be aggressive but it can also behave in a more indolent fashion in some patients. MCL comprises about 5% of all NHLs. The disease is called Mantle Cell Lymphoma because the tumour cells originally come from the 'mantle zone' of the lymph node (Zhou et al., 2004). Pretreatment Hodgkin's lymphoma with calcification may masquerade as other second primary pathologies, e.g. extraosseous osteosarcoma or myositis ossificans (Apter et al., 2002; Korek-Amorosa et al., 1974). A calcified perineural lymphoma prior to treatment is exceedingly rare and calcification usually occurs one to five years after chemotherapy or radiation therapy with an incidence of 2% (Apter et al., 2002). This case documents how the manifestation of a rare malignant perineural mantle cell lymphoma may be indistinguishable from other pathological entities based on its pattern of distribution in a combined FDG- PET-CT study.Mantle Cell Lymphoma, PET-CT, FDG, calcification, perineural
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Abstract (Viewed: 1)A Meshless Time Domain Method is used in the local support domain to solve Maxwell's equations for one-dimensional transient electromagnetic problems. The approach is based on a combination of the Meshless Radial Basis Functions and the Leapfrog time-stepping scheme for the Finite-Difference approximation of the first order partial derivatives. A comparison is performed between the conventional FDTD and RBF's with Gaussian, Wendland-C4 Compactly Supported RBF (CSRBF) and Inverse Multi-Quadric (IMQ) basis functions. The numerical results showed that the proposed method provides an accurate solution for transient electromagnetic problems.Finite-Difference-Time-Domain, Local Support, Meshless method, Compact support RBF, Inverse Multi-Quadric, Transient Electromagnetic Field
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(Downloads: 51)
Abstract (Viewed: 2)Steganography is one of the techniques used for secure transmission of secret information. The secret information is concealed in a carrier and transmitted. Video steganography uses video signals to hide the secret information. The objective of this paper is to hide large volumes of secret data in video files. In the proposed technique, AVI video files are used as the carrier. Video files containing audio are split to get video and audio frames. Video frames are like still images and so, can be used for image steganography. When audio is extracted from the video, it is like an audio file and it can also be used for steganography. This leads to the high capacity steganography, since both video and audio frames are used as the carrier. When a small video clip is read, thousands of video and audio frames will also become available. The secret data can be image, audio or text. In this proposed work, secret image and audio signals are hidden in the video file.Capacity, Integer Wavelet Transform, Peak Signal to Noise Ratio, Structural Similarity Index Metric, Video Quality Metric (VQM), Video steganography
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Abstract (Viewed: 6)One of the best ways to enhance heat transfer coefficient is by improving thermal properties of the working fluid. Gold/water nanofluid flow through horizontal minitube with very low Reynolds number was simulated by using Thermal Lattice Boltzmann Method (TLBM) under uniform heat flux boundary condition. The effect of different volume fraction of nanoparticles on the heat transfer coefficient was studied and compared with the base fluid (water). The results were verified using Finite Volume Method (FVM). The results showed enhancement of heat transfer coefficient when using gold/water nanofluid and this enhancement depends on the volume concentration of Gold nanoparticles. The maximum enhancement was 18% with 0.03 volume concentration.Convective heat transfer, Gold nanoparticles, Nanofluids, TLBM, Axisymmetric, Laminar flow
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Abstract (Viewed: 1)The purpose of this research is to gain initial knowledge and to predict the sustainability of an all-weather Micro-Aerial-Vehicle (MAV). The observed parameters are: the maximum coefficient of lift, CL and the changes in CL after impact, the fluctuation of CL upon entering simulated rain environment, and length of stability recovery in terms of time and flapping cycle, t and t/T, at flapping frequencies of 8, 16, and 24 Hz, at t/T = 3/8 and 7/8. At 24 Hz, the increase in peak CL value after impact of entering rain environment is 0.59. The average fluctuations in CL occurred when entering the rain environment are 410.263. The stability recovery time recorded is 0.006 seconds. Small birds (especially hummingbirds) have a very high flapping frequency that enables them to efficiently withstand external disturbances caused by nature and to instantly adapt to new environments.Membrane wing, flapping, flat plate, inter-domain, flapping stability, simulated rain
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(Downloads: 42)
Abstract (Viewed: 2)Flow separation over blade surfaces is an important parameter and its reduction or elimination can improve better aerodynamic performance, efficiency and stall margin. In this work, numerical investigation has been carried out to study the flow separation and performance analysis of a transonic axial compressor rotor blade at off-design operating conditions. The off-design cases studied comprised of compressor operation at 80%, 90%, 100% and 105% on the on-design rotational speed. The results are validated with experimental work from literature. Additionally, 3D flow visualisations and performance parameters were examined in detail to understand the blade to blade relative mach number distributions and shock front created by the model. Finally, the benefits of unsteady simulation on axial compressor blade performance predictions were examined.Compressor rotor blade, Numerical investigation, Flow separation, Off-design cases, Shock front, Efficiency
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Abstract (Viewed: 3)A new numerical scheme based on the particle method, namely the Moving Particle Pressure Mesh (MPPM) method, has been previously developed by the authors to address the limitation of the conventional Moving Particle Semi-implicit (MPS) method in simulating incompressible flow. In this paper, we shall investigate on a more practical way to extend our MPPM method to handle complex geometry, i.e. by employing an embedded unstructured mesh system to cope with an arbitrarily-complex flow domain. No-slip boundary condition is modelled via placing a series of fixed particles at the wall boundaries, negating the use of ghost particles which are difficult to generate. In order to verify our numerical procedure, the vortex-shedding process behind a cylinder is computed and it is found the numerical result is agreeable with the reference solution.Moving Particle Semi-implicit (MPS), Moving Particle Pressure Mesh (MPPM), CFD, incompressible flow, unstructured mesh, semi-Lagrangian
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(Downloads: 43)
Abstract (Viewed: 3)There are many contributions from synthetic fibres in the world of industrial composites over the years. However, they contain hazardous properties to humans causing irritation when exposed to the skin and eye. Inhalation of fibrous synthetic can cause lung cancer with its deadly effects. There have been studies and researches conducted on natural fibres to replace synthetic fibres as it is believed the latter are more environmental-friendly and pose less health risks to humans. The aim of this study was to investigate hoop tensile properties of the composite hollow shaft for different winding angles and PVC reinforcement produced via the filament winding technique. For this purpose, split-disk tests (according to ASTM D-2290 standard) were performed for the specimens produced with two different winding angles such as 45o and 90o winding angle. By determining the hoop tensile strength and modulus of these specimens, the effects of filament-winding processing parameter in winding angle were evaluated. Experiments successfully showed that the mechanical properties such as tensile properties of kenaf yarn fibre reinforced unsaturated polyester hollow tube at 90° and 45° winding angle with and without PVC. The value was 15% for the different winding angles and 25% for the different winding angles with and without PVC. The results indicate that 90° fibre winding angle kenaf yarn fibre unsaturated polyester with PVC has the highest hoop tensile strength compared with other composite specimens. The experiments concluded that the orientation on fibre angle has a significant impact on the hoop tensile strain, hoop tensile modulus and hoop tensile strength properties.Split-disk tests, filament winding, composite tube, hoop tensile strength, hoop modulus of elasticity
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(Downloads: 61)
Abstract (Viewed: 10)Information and communication technologies (hardware and software), have become an important part in classroom learning because they allow diversity in learning styles and make learning more flexible. This study focuses on Tracker, a free video analysis and modeling software, which offers an alternative route to discuss concepts that are otherwise difficult to grasp. Using the popular game, Angry Birds, we demonstrate the ongoing research on the application of Tracker in three cases: 1) motion of exploding projectile, 2) free fall with air resistance, and 3) calibration of a home-made spectrometer. Findings reveal that such visualizations can offer an alternative way to explain concepts that are otherwise rather difficult to grasp in Physics. Findings from these experiments open up exciting possibilities on the need for future research in more advanced research themes like determining diffusion coefficient and absorption spectra of materials.Tracker, parabola, momentum conservation, air resistance, spectrometer, physics
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(Downloads: 39)
Abstract (Viewed: 2)With the proliferation of Web 2.0 technologies, folksonomy which is also known as social tagging or collaborative tagging is widely used by learners to annotate and categorize their learning resources. In a folksonomy system, the tags are added by learners to the learning resources, hence the tags are often ambiguous, overly personalised and imprecise. In addition, conjugated words, compound words and nonsense words may be used in tagging and shared among a group of learners. This has resulted in an uncontrolled and chaotic set of tagging terms that cause learning resources searching, reuse and sharing to become ineffective. In this paper, we present a content-based approach which automatically generates tags from a learning resource using Part-Of-Speech Tagging and K-Means Clustering techniques. The generated tags are more precise and unambiguous which can improve learning resources searching, reuse and sharing among learners.Folksonomy, clustering, K-Means, Part-of-Speech, collaborative tagging, learning content reuse, learning content Sharing, learning process, automatic tagging
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(Downloads: 57)
Abstract (Viewed: 5)Malaysian Studies is a compulsory course for international undergraduate students in Malaysia. The subject comprises Malaysian history, its governance and administration system. Due to different socio-cultural backgrounds and histories, most, if not all, international students, struggled with this subject. This research project aims to create, implement and evaluate a mobile application (app) as a catalyst for mobile learning (m-learning) for one particular topic of the Malaysian Studies course. The increased use of technology in learning environments has changed instructional approaches by making it more accessible and essentially, more student-centered. Using a design-based research approach, the mobile app is aimed to guide students to write their own notes to assist in deeper understanding of the subject. The mobile app was also reviewed by users to gauge its effectiveness and ease of use. Findings from the tests showed the potential to structure the students' learning from the topic. From the research, there are a few improvements and suggestions that could be implemented for similar future studies and projects.Mobile learning, m-learning, technology-based learning environment, constructivist learning, Malaysian Studies, Malaysian governance components, student engagement, design-based research
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(Downloads: 81)
Abstract (Viewed: 8)The purpose of this research is to analyse the impact of identified variables to adapt change management due to e-learning implementation in Malaysian private higher education institutions focusing on educators' perspectives. The conceptual framework was modified in combination of various theories from Systemic Change Models and E-learning Cycle Models. A self-administered questionnaire adapted from Siebel 4.0-2 Survey Questionnaires (SSQ) by Hambling, 2010 was the data collection instrument. The sample consisted of educators from private higher education institutions with visions or missions based on e-learning implementation in Malaysia. As per findings, through review of the visions and missions, the selected private higher education institutions integrated teaching and learning, advancement of the knowledge based on e-learning and leadership in service and outreach.Change management, e-learning, vision, mission, private higher education, implementation

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