Jafri Rohani | Universiti Teknologi Malaysia - UTM (original) (raw)

Papers by Jafri Rohani

ARPN journal of engineering and applied sciences, Sep 27, 2013

This study suggest a set of steps of combining different indicators to form a single index which ... more This study suggest a set of steps of combining different indicators to form a single index which may become a significant measurement in comparing, ranking and determining road safety levels in different countries and however, to create a valuable road safety performance index in terms of communication, benchmarking, policy making and monitoring. Many composite (multidimensional) indices have been developed internationally and used in different aspects of life to indicate a progress or achievements between countries. They cover environmental issues, sustainable development, globalization issues, agriculture, economy, information technology, and more. Taking the specific road safety case into account, this study describes the different steps that are essential in the construction of a road safety performance index. The selection of indicators and data preparation are described, the issue of weighting and aggregating indicators is discoursed and the degrees of the index in terms of ranking of the countries assessed. These steps are illustrated by two weighting methods of simple average and based on theories using performance indicator data for ten African countries.

IOP Conference Series: Materials Science and Engineering

Jurnal Mekanikal, Jun 1, 2010

The present study highlights the instrument development to measure the relationship between stati... more The present study highlights the instrument development to measure the relationship between statistical process control success factors construct and performance construct. From an extensive review of literature of statistical process control implementation, eleven dimensions of statistical process control success factors and three dimensions of performance were identified. In this paper, a survey instrument to measure SPC success factors construct associated with quality and firm performance was proposed. The reliability and validity of this survey instrument were tested using data from 122 respondents. It was concluded that instrument developed in this paper has satisfactory psychometric properties, reliable and valid. Hence the researcher can use this survey instrument to build the model to find the relationship between statistical process control success factors construct and performance construct. Industrial practitioners can use this survey instrument to identify and predict the success of their SPC implementation projects through managing of these associated factors.

Jurnal teknologi, Sep 10, 2013

Construction managers and planners are always involved in answering questions regarding the effec... more Construction managers and planners are always involved in answering questions regarding the effects of changing the level of resources involved in construction activities on project performance. The planners strive to determine the best resource level combination that optimizes the performance measures such as productivity. In this study, a unique approach involving the combined use of a powerful Quality Engineering tool, Design of Experiment (DOE) and Simulation for determining the best combination of resources level for a real-world construction process, viz. concrete pouring process. DOE enabled the experimental plan to be designed in the form of a twice replicated, 24 full factorial designs with 5 center points. This experimental plan involved 37 experiments. Simulation has enabled the construction process investigated to be realistically modelled. Therefore, instead of performing field trials involving 37 experiments, these experiments are simulated in order to obtain the response investigated, which is productivity. A model, for predicting concrete pouring process productivity, was successfully developed and the optimum resources level was also determined.

World applied sciences journal, Feb 18, 2013

The occurrence of back pain and its associated risk factors were investigated among school childr... more The occurrence of back pain and its associated risk factors were investigated among school children in Nigeria with the aim of developing a robust predictive back pain model. Data were obtained using a selfreported questionnaire which was distributed to 255 schoolchildren, aged 8 to 13 years. After data screening, SPSS was used to analyze responses from 212 subjects. Exploratory factor analysis and logistic regression were used as complementary statistical techniques to develop a robust model consisting of variables representative of the population. The EFA identified the significance and interaction of the mechanical backpack factor, psychosocial pain effect or feeling factor and the Individual activities factor while the logistic regression model also identified four variables that are significantly associated with back pain among the children. They are Closeness to school (OR=3.991; 95% CI 1.802-8.836), when pain started (OR=4.159; 95% CI 1.886-9.169), the use of back pack (OR=10.926; 95% CI 4.836-24.686) and exposure to computer games (OR=2.509; 95% CI 1.057-5.953). The study showed high prevalence of back pain among Nigerian school children and identified mechanical, psychosocial and individual factors as the major contributors of back pain among them.

Applied Ergonomics, 2017

The study analysed backpack-related back pain in school children by investigating the possibility... more The study analysed backpack-related back pain in school children by investigating the possibility of multiple interactions among causative factors, which may be responsible for the non-conclusive findings on the issue. Using data from 444 prepubescent schoolchildren, a mixed method design combining survey, observation and direct measurement strategies was implemented. Using a multivariate structural equation modelling approach, the study investigated interactions among anthropometry, posture, backpack volume, rating and back pain constructs, with each construct made of 2-4 indicators. Additionally, regression analysis was used to determine the feasibility of considering the two additional factors of age and body mass index along with the globally accepted recommendation of a load of 10-15% of body weight. Our model demonstrated an acceptable model fit and revealed direct and indirect effects of the factors. Obese children were recommended to carry a one-third lighter load than other children. The application of systematic/multiple strategies provided an explanation for some of the issues associated with school children's backpack-related back pain.

ABSTRACT Back pain among school children using backpacks is still a problem and generating intere... more ABSTRACT Back pain among school children using backpacks is still a problem and generating interest from academia. Most research has been limited in scope. While some researchers carried out experimental investigations using biomechanical and physiological principles, others based their research on psychosocial issues. The inability to recognize the complexity of factors that affect this issue may explain why conflicting results have been obtained by different researchers. Presently, a general recommendation for a backpack weight of 10–15% of body weight has been accepted as a standard. But recent findings still indicate back pain among backpack users in schools. The purpose of this paper was to develop a holistic backpack-back pain model that is based on concurrent research, including: biomechanics, psychosocial and physiological factors. A systematic approach was taken in evaluating relationships among the various factors thereby proposing a model that can serve as a tool for evaluating contextual issues involving backpack design and use and back pain.

Advances in intelligent systems and computing, Aug 5, 2018

Racial differences associated with variation in diet, climate and culture, may pose a challenge i... more Racial differences associated with variation in diet, climate and culture, may pose a challenge in developing a globally acceptable safe backpack weight for schoolchildren. This study therefore investigates the suitability of a multivariate backpack-related back pain model in a multiracial society such as Malaysia. Back pain related data from an average of 205 Malay, Chinese and Indian Schoolchildren were fitted into a proposed backpack-related back pain model and also into a regression model to predict safe weight from percentage body weight (PBW), body mass index and age in order to determine the level of fit. While the three racial models met the minimum requirements of the different goodness-of-fit indices, there were uncaptured significant relationships peculiar to each racial model in the proposed model. Notwithstanding, the combination of age, BMI and PBW are better predictors of back pain occurrence among the children in the three ethnic groups.

Mohd. Rohani, Jafri and Mohd. Yusof, Sha'ri and Mohamad, Ismail (2007) Deriving a relationsh... more Mohd. Rohani, Jafri and Mohd. Yusof, Sha'ri and Mohamad, Ismail (2007) Deriving a relationship between success factors and quality performance in statistical process control implementation: a hypethetical model for empirical investigations. In: 9th Islamic ...

Cogent Medicine, Nov 19, 2014

The global rise in the prevalence of childhood overweight and obesity has necessitated the need f... more The global rise in the prevalence of childhood overweight and obesity has necessitated the need for global standards, which is very important for cross-cultural or national comparisons, and to assess the effectiveness of various proposed measures of body composition. In this paper, the body composition of 411 children, consisting of 163 boys and 248 girls, aged 10.49 ± 1.12 years, was analysed based on body mass index (BMI) and two body fat references from Korea (BFK) and the UK (BFUK). BMI was the most sensitive estimate of adiposity (overweight = 15.8%; obesity = 6.6%), when compared with BFUK (overweight = 7.8%; obesity = 3.2%) and the BFK (overweight = 10.2%; obesity = 0.5%). Although, there was significant correlation between BFK and BFUK (r = 0.89, p < 0.0001), BFK and BMI (r = 0.644, p < 0.0001), and BFUK and BMI (r = 0.646, p < 0.0001), they fairly agreed (intraclass correlation coefficient = 0.537), as BMI reliably estimated body fat in normal weight, but overestimated body fat in overweight and obese children. Of all the demographic and physical activity variables, only gender was significantly associated with difference in body fat estimation, as BMI estimation of body fat was higher in girls than in boys. Hence, we must be cautious in using BMI as a surrogate for body fat, especially among overweight and obese children.

Penerbit UTM eBooks, 2008

This paper presents a comparison between learning organization culture in New Zealand and Malaysi... more This paper presents a comparison between learning organization culture in New Zealand and Malaysian manufacturing companies. Learning organization was measured by using Watkins and Marsick's Dimension of Learning Organisation Questionnaire (DLOQ) survey questionnaire. The collected data were analysed to assess the reliability and validity of the measurement score of the DLOQ. The data were further analysed so as to determine the differences between New Zealand and Malaysian companies with respect to the presence of a learning organisation-oriented culture. Results of the analysis show that DLOQ are equally reliable and valid in both New Zealand and Malaysian manufacturing context. It was also found that there are significant differences between New Zealand and Malaysia in several dimensions of learning organisation; namely team learning, dialogue inquiry and empowerment. The differences may be attributed to cultural differences between New Zealand and Malaysia.

Applied Mechanics and Materials, Aug 1, 2014

With advent of technology, simulation software becomes more applicable between organizations' man... more With advent of technology, simulation software becomes more applicable between organizations' managers. Simulation can model the real situation on a visual program. It will make the understanding of system, properly. Nowadays in each organization, the main factor is how to improve its services. This study emphasizes on customer satisfaction and reducing the waiting time for customers in a bank service system. The goal of this paper is applying ARENA simulation software for modeling the system and measuring the performances. In addition, three strategies were implemented that each strategy consists of several scenarios. 17 possible scenarios were compared to achieve all kind of results that can be imagined. It is expected that it would be helpful for manager to analyze and compare the results and find the lowest and highest effective elements for improvement.

Jurnal teknologi, Dec 29, 2016

In recent years, researchers have demonstrated increases interest in studies involving silicon ca... more In recent years, researchers have demonstrated increases interest in studies involving silicon carbide (SiC) materials due to several industrial applications. Extreme hardness and high brittleness properties of SiC make the machining of such material very difficult, time consuming and costly. Electrical discharge machining (EDM) has been regarded as the most viable method for the machining of SiC. The mechanism of EDM process is complex. Researchers have acknowledged a challenge in generating a model that accurately describes the correlation between the input parameters and the responses. This paper reports the study on parametric optimization of siliconized silicon carbide (SiSiC) for the following quality responses; material removal rate (MRR), tool wear ratio (TWR) and surface roughness (Ra). The experiments were planned using Face centered central composite design. The models which related MRR, TWR and Ra with the most significant factors such as discharge current (Ip), pulse-on time (Ton), and servo voltage (Sv) were developed. In order to develop, improve and optimize the models response surface methodology (RSM) was used. Non-linear models were proposed for MRR and Ra while linear model was proposed for TWR. The margin of error between predicted and experimental values of MRR, TWR and Ra are found within 6.7, 5.6 and 2.5% respectively. Thus, the excellent reproducibility of this experimental study is confirmed, and the models developed for MRR, TWR and Ra are justified to be valid by the confirmation tests.

DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2021

Advances in Intelligent Systems and Computing, 2018

Musculoskeletal disorder (MSDs) are major occupational health issues among the private sector and... more Musculoskeletal disorder (MSDs) are major occupational health issues among the private sector and government. This paper analyzed total direct cost being paid by the Social Security Organization of Malaysia (SOCSO) to the Malaysian workers due to musculoskeletal disease. Total direct cost consists of compensation cost, return to work and rehabilitation cost, and medical cost. The objectives of this study are (1) to determine the total direct costs incurred as a result of cases of chronic musculoskeletal injuries approved by SOCSO from 2010–2014. (2) To examine the age category imposed for the total average cost on the highest MSDs claims for the four categories setting. This study has utilize data provided by Social Security Organization of Malaysia (SOCSO) on occupational diseases and adopt top-down approach. The claims data is limited to MSD reported between 2009 until 2014. A total of 416 claims related to MSD has been analyzed. All the category recorded the highest total direct ...

This study analyzes compensation cost paid by the Social Security Organization of Malaysia (SOCSO... more This study analyzes compensation cost paid by the Social Security Organization of Malaysia (SOCSO) to the Malaysian manufacturing workers due to MSD related cases. The study compares MSD related cases based on three categories: cause of accident, type of injury and location of body injury against "older" workers and "younger" workers and gender differences. This study adopted top-down approach which utilized national statistics related to MSD claims data provided by SOCSO. The claim data is limited to MSD reported cases from 2009 to 2014. A total of 537 claims which related to MSD has been recorded in Malaysia within that period. The highest number of cases based on cause of accident is due to strenuous movement with average compensation cost at RM 28 400 (male younger workers) and RM 22 738 (male older workers). Besides, most of the claimants sustain MSD injury at the back body region. with average compensation cost of RM 28 117 (male younger workers) and RM 21 ...

Musculoskeletal disorder (MSD) among workers is a major cause of lost workdays in industries and ... more Musculoskeletal disorder (MSD) among workers is a major cause of lost workdays in industries and also accounted for the highest rate of disability among workers. (WHO 2003, Gallagher and Heberger 2012). It has led to loss of productivity and has become a high financial burden on national health systems (Chiasson et al. 2012, Gallagher and Heberger 2012). These negative effects needs to be prevented, as much as possible, especially in developing countries whose industries are just developing, and such effects can constitute serious obstacle to their drive for industrialization. This serves as justification for this study, which investigated MSD among Malaysian workers, and also developed a model highlighting the direct and indirect effect of physical and psychosocial factors on workers satisfaction.

The paper underlines the initial work that is aimed at investigating the critical process and wor... more The paper underlines the initial work that is aimed at investigating the critical process and work-related symptoms that contribute to ergonomic and noise hazard furniture production industry. The effectiveness of the current existing control measures are also identified. Furniture industry is a manufacturing industry that employs a large workforce. There are many cases of occupational health diseases reported in 2016 from the manufacturing sector in Malaysia. The highest diseases reported are noise-induced hearing loss and musculoskeletal disorders. Therefore, in this project, the focus is on the ergonomic and noise hazards in the furniture industry in Malaysia. The project will be done by using three methodologies. The methodologies are four sections questionnaire or survey, direct observation using RULA and REBA, and direct measurement to measure the noise exposure level in the working place.

The objectives of this study are to identify the level of safety culture in terms of the percepti... more The objectives of this study are to identify the level of safety culture in terms of the perceptions of the beliefs on the importance at workplace (SCB) and the existing safety culture practice (ESCP), to find out the level of SCB, and to identify to what extend safety is being closely practiced (ESCP) amongst Safety and Health Officers (SHOs). A questionnaire was sent to 173 SHOs in Malaysian manufacturing companies and 146 questionnaires were successfully returned. 22 questions related to self-regulations, commitment, motivation and communication which were identified through literature. Each respondent needs to rate his or her level of understanding of SCB and ESCP. Mean score analysis was used to determine the level of understanding of SCB and ESCP. Subsequently the differences between the two components are shown in a radar graph. The details of the items in identifying the levels of SCB and ESCP were analyzed. The study found the level of SCB is between medium high to high. Ho...