Siti Zawiah Md Dawal

University of Malaya | UM · Department of Mechanical Engineering

In the past ten years, the increasing customer awareness of environmental sustainability has driven the development of green products. As the initiator of product development, this situation can challenge product designers. Since customers may have varied expectations and preferences for green products, it depends on the green attributes embedded i...

Chair comes in different sizes and shapes depending on the functions as well as the users involved. However, the designers seldom consider the ergonomics aspect in chair design. This research has been conducted as a case study to compare and select the best design parameters within two chairs known as Chair A and B using human modelling software ca...

This article considers the extension of the job sequencing and tool switching problem with sequence-dependent setup times (SDSSP) and with the requirement to comply with the due date of the processed jobs. This extension is motivated by the practical application in manufacturing environment where the products manufactured may be subjected to a spec...

Chair comes in different sizes and shapes depending on the functions as well as the users involved. However, the designers seldom consider the ergonomics aspect in chair design. This research has been conducted as a case study to compare and select the best design parameters within two chairs known as Chair A and B using human modelling software ca...

The oil palm industry is one of the important sectors in Malaysia. The growth and development of this industry shows that Malaysia is the world second-largest oil palm producers. However, in the fresh fruit bunch (FFB) harvesting process, the harvesters are exposed to many types of work-related musculoskeletal disorders (WMSDs). The FFB harvesters...

Work productivity is one of the most important economic measures in the manufacturing industry. However, the physical, psychosocial, and individual risk factors of an industrial work environment affect workers' physical or mental health, resulting in work productivity loss, absenteeism, and presenteeism. Therefore, this study aims to identify the m...

The ageing drivers’ population is increasing rapidly, and they are exposed to disabilities due to degenerative processes, thus affecting their driving performance. The main objective of this study is to determine the mental workload of ageing drivers, while the second objective is to compare the mental workload between ageing drivers and control gr...

Purpose There is an increasing awareness among manufacturers to make production more sustainable in Southeast Asian countries such as Malaysia and Indonesia. Manufacturers are now urged to not only focus on the business profit but also concern on environment protection by producing green products. However, issues may arise regarding the preferences...

This study develops an improved hybrid genetic algorithm-simulated annealing (IGASA) algorithm to solve the reentrant flow-shop scheduling problem with permutation characteristics. The reentrant permutation flow-shop (RPFS) allows the jobs to visit certain machines more than once and has been proven to be an-hard problem. The proposed improved hybr...

The increasing customer awareness of environmental sustainability during the last decade has had an influence on many manufacturers to produce green products. However, issues arise regarding the actual preferences of customers for green products, which often differ depending on cultural influences. Cultural values can affect the decisions of design...

The involvement of ageing drivers in traffic accidents were reported but little cited on the severity of auditory driving distractions. Driving distraction contributes to increases in reaction time which can lead to safety traffic risks. Thus, in this study, hand and foot reaction times were measured in response to different distractions within the...

Whiplash injury due to low severity vehicles crash is a global problem. The injury has long-term clinical and biomechanical implications. Since the mid-1960s, injury statistics have continuously revealed that females face a higher risk of suffering the injury category compare to males. Besides, in a frontal crash, the injury measures from the adult...

An investigation on ablution workstations design for person with disabilities has been carried out in this study. The focused were on wheelchair user or person with lower-limb impairment in Malaysia. The objective of this research is to determine the most suitable ablution workstation for person with disabilities. One hundred wheelchair users which...

Existing computer vision methods to measure surface roughness rely on feature extraction to quantify the surface morphology and build prediction models. However, the feature extraction is a complicated process requiring advanced image filtering and segmentation steps, resulting in long prediction time and complex setup. This study proposes the use...

Driving an automobile is the most convenient transport as many individual faced difficulties when using other transportation options, particularly public transport facilities and even walking. The Malaysian Driver Behaviour Questionnaire (DBQ) was included as a part of questionnaire survey to determine the factors that affect the driving behaviour....

The World Health Organization stated that the global ageing population is increasing rapidly as well as the case of road accidents involving ageing drivers. This study presents the driving mental workload and performance model of ageing drivers in the context of real-time road driving. Twenty paid participants (ten males) with a mean age of 57.8 ye...

Background Extensive studies have been carried out over the years to determine the maximum acceptable weight that a worker is capable of lifting in a given situation among Occidental populations across Europe and US. Nonetheless, studies that place emphasis on using lifting frequency as the quantifying task parameter, especially in developing count...

This study proposes a scoring system for safety performance of offshore oil and gas platforms in Malaysia. The scoring system is based on the 14 most pertinent safety factors capturing key safety areas of the Malaysian offshore oil and gas platforms. Compliance scores of the safety factors were generated by summing the products of the respective in...

Nowadays, increasing awareness is directed toward the fulfilment of sustainability demands in production in rapidly developing Southeast Asian countries such as Indonesia. However, producing green products that satisfy customer preferences is still a challenging task for product designers and manufacturers. Cultural values can be a significant fact...

Nowadays, increasing awareness is directed toward the fulfilment of sustainability demands in production in rapidly developing Southeast Asian countries such as Indonesia. However, producing green products that satisfy customer preferences is still a challenging task for product designers and manufacturers. Cultural values can be a significant fact...

Universal design refers to wide range of ideas intended to establish facilities that are naturally applicable to small population like people with disabilities (PWDs), and subsequently, for older people, adults, and children. In that case, an anthropometric database for the Malaysian wheelchair users population should be initiated. A total of 52 pa...

Human factors / ergonomics (HFE) focuses on the interaction of human with the environment. The traditionally concept of HFE has always focused on the interrelationship between three main elements of human-machine-environment. Therefore, significant to this research was that an integrated Malaysian train driver performance model has been successfull...

The purpose of this paper is to address the development an integrated performance model of train drivers. A human performance measure was developed by integrating several significant factors of the train driver. The evaluation was conducted on train drivers of a major train operating company (TOC) in Malaysia, focusing only on drivers of intercity...

Introduction: This study establishes the correlations between performance of a set of key safety factors and the actual lagging performance of oil platforms in Malaysia, hence the relevance of the key safety factors in evaluating and predicting the safety performance of oil and gas platforms. The key factors are crucial components of a safety perf...

An anthropometric database for sitting and standing dimensions for Malaysian operators was developed based on the measurements from 146 male and 168 female participants (18–45 years old). The anthropometric data were subsequently compared to those from three selected Asian countries, focussing on the sitting and standing posture dimensions. Thirty-...

Ankle Foot Orthosis (AFO) is a brace or device that is worn on the lower leg to support and correct the foot and ankle position. AFO is also used to correct the foot drop. In this paper, a new design of AFO is proposed and its analysis using AUTODESK Inventor will be discussed. The design concept was based on the short and long size of pneumatic ar...

The aim of this study is to investigate the mediation effects of muscle activities on the relationship between production standard time and work productivity. The work productivity and muscle activities data are collected from twenty workers (10 males, 10 females) while performing industrial repetitive tasks at three different levels of production...

This paper aims to investigate the variation of work productivity and muscle activities among workers performing industrial repetitive tasks at four different levels of production target. The work productivity and muscle activities data were recorded from twenty workers at four levels of production target corresponding to "participative (PS1)", "no...

Scheduling in flexible manufacturing systems (FMS) is described as an NP-Hard problem. Its complexity has increased significantly in line with the development of FMS over the past years. This paper presents a non-dominated sorting biogeography-based optimization (NSBBO) for scheduling problem of FMS having multi loading-unloading and shortcuts infu...

This study evaluated drivers' mental workload in real time driving to identify the driving situation's complexity influences in an attempt to further design on a complete experimental study. Three driving settings were prepared: Session A (simple situation); Session B (moderately complex situation); Session C (very complex situation). To determine...

Wudu' (Ablution) workstation is one of the facilities used by most Muslims in all categories. At present, there are numbers of design guidelines for praying facilities but still lacking on wudu' (ablution) area specification especially or elderly. Thus, It is timely to develop an ergonomic wudu' workstation for elderly to perform ablution independe...

A gear-based knee joint is designed to improve the performance of mechanical-type above-knee prostheses. The gear set with the help of some bracing, and bracket arrangement, is used to enable the prosthesis to follow the residual limb movement. The motion analysis and finite-element analysis (FEA) of knee joint components are carried out to assess...

Programming codes for hybrid GA-PSO. (PDF)

In Malaysia, oil and gas industry is a major contributor to the economy. Offshore plants pose a number of operational hazards. It is important to monitor the operational hazards by using relevant safety indicators for proactive prevention of accidents in the plants. This research aims to identify the most pertinent safety indicators for offshore oi...

Over the past few years, there have been increasing efforts to promote green products in developing nations. However, evaluating customer preferences when it comes to choosing green products is a rather complex task, which is perhaps due to the influence of cultural values on customer preferences. Hence, the objective of this study is to examine th...

Manual Material Handling (MMH) involves lifting, bending, and twisting motions of the torso. Poor lifting technique is often considered a major risk factor in low back injury associated with manual lifting tasks. Currently, there is little work on the effects of lifting on the Malaysian population. The MMH activities that was designed with the diff...

Ankle foot orthosis (AFO) are commonly used to correct the instabilities and joint weakness of lower limb. In this research, AFO was developed by using pneumatic artificial muscle (PAM) to prevent plantarflexion to occur and also to correct the foot from the inversion syndrome. The research started with designing the AFO by using SolidWorks softwar...

Work productivity is typically associated with production standard times. Harder production standards generally result in higher work productivity. However, the tasks become more repetitive in harder production standard time and workers may be exposed to higher rates of acute responses which will lead to higher risks of contracting work-related mus...

Scientific Reports 6 : Article number: 27380; 10.1038/srep27380 published online: 07 June 2016 ; updated: 25 August 2016 In this Article, Hwa Jen Yap, Siti Zawiah Md Dawal, S.

This study investigated the variation of work productivity performance at different levels of production standard time. Twenty subjects performed repetitive tasks at three different levels of production standard time, corresponding to “normal, “hard” and “very hard”. The work productivity and perceived fatigue were recorded. Analysis of Variance (A...

This study presents a modular-based implementation of augmented reality to provide an immersive experience in learning or teaching the planning phase, control system, and machining parameters of a fully automated work cell. The architecture of the system consists of three code modules that can operate independently or combined to create a complete...

The metal cutting process initiates with the occurrence of plastic deformation of workmaterial and is followed by tear and removal of material from the workpiece. This process ultimately damages cutting tool and causes tool wear. An acoustic emission (AE) sensor has been employed to measure the signal frequency in machining. The AE signal component...

The purpose of this study was to investigate the different effect from the two standing posture on lower limb fatigue and discomfort. Sixteen subjects (eight females and eight males), aged between 23-29 years, participated in the experiment. They performed a sorting task in front of a grading table by picking and placing objects for 90 minutes in t...

The conveyor system plays a vital role in improving the performance of flexible manufacturing cells (FMCs). The conveyor selection problem involves the evaluation of a set of potential alternatives based on qualitative and quantitative criteria. This paper presents an integrated multi-criteria decision making (MCDM) model of a fuzzy AHP (analytic h...

Questionnaire design for multi-criteria decision making in conveyor evaluation and selection (PDF)

This study was conducted to develop muscle and mental activities on repetitive precision tasks. A laboratory experiment was used to address the objectives. Surface electromyography was used to measure muscle activities from eight upper limb muscles, while electroencephalography recorded mental activities from six channels. Fourteen university stude...

Background: Ergonomics standards play an important role in product and system design as it can improve their usability; provide comfort and safety for the users. The number of musculoskeletal diseases has increased in recent years in Malaysia. However, the awareness and importance of ergonomics in Malaysia is still very low among the industries. Ma...

Background: Ablution area is one of the facilities used by most Muslims in all categories. There are numbers of de-sign guidelines for praying facilities but lack on ablution area specification. Therefore, this study was conducted to design an ergonomic ablution area for the Muslim’s disabled and elderly based on their preferences and anthropomet-r...

Most studies have examined the association of ergonomic risk factors and musculoskeletal discomfort in developed countries. Meanwhile the data are still lacking in developing countries such as Malaysia. The aim of this study was to determine the relation between risk factors and musculoskeletal discomfort among manual material handling workers in M...

It was suggested by most researchers that train drivers' workload and alertness levels attribute to train accidents. The main objective of this study is to determine the significant patterns of mental workload and alertness levels of train drivers with respect to the conditions. The data are collected from simulation experiments on 15 professional...

Extensive research has been carried out over the years to determine the maximum acceptable weight that a worker is capable of lifting in a given situation among the Occidental populations in the Europe and US. At present, there is a scarcity of studies in which lifting frequency is used as the measuring variable, especially in developing countries...

Ergonomics is generally to design for human use and optimizing the working and living conditions. The comfort, safety and ease of use of systems, products and machines require the principles of ergonomics to be incorporated into the design. Anthropometry is a part of ergonomics which deals with the measurement of body dimensions, its capability and...

It is known that lifting tasks are one of the risk factors of musculoskeletal disorders in the automotive industry. Extensive research has been carried out over the years to develop guidelines and determine safe limits in which an individual can lift. For this reason, the objective of this study is to determine the significant risk factors of muscu...

This study focuses on the application of the Malaysian Driving Behaviour Questionnaire(DBQ). The aim of this study is to investigate and analyse the significant driving behaviour of the ageing Malaysian automobile drivers. The sets of questionnaire was completed by a total number of 102 ageing drivers consists of 58 males (56.86%) and 44 females (4...

This paper presents the review of the ergonomic on workstation for disable student in higher education. Most of disable especially in term of physically disable student has limitation in their study area, which highlighted here as workstation. The main objective of this paper is to discuss the significant role of ergonomic workstation for disable s...

It is known that the ageing process will result in a decrease in anthropometric dimensions as well as loss of hand grip strength, which is natural among elderly people. Previous studies have shown that the decrease in anthropometric dimensions may influence hand grip strength of elderly people. Hence, this paper seeks to determine the relationship...

Factory management plays an important role in improving the productivity and quality of service in the production process. In particular, the distributed permutation flow shop scheduling problem with multiple factories is considered a priority factor in the factory automation. This study proposes a novel model of the developed distributed schedulin...

Globalization of business and competitiveness in manufacturing has forced companies to improve their manufacturing facilities to respond to market requirements. Machine tool evaluation involves an essential decision using imprecise and vague information, and plays a major role to improve the productivity and flexibility in manufacturing. The aim of...

[Purpose] The purpose of this study was to investigate the effects of energy expenditure rate on work productivity performance at different levels of production standard time. [Subjects and Methods] Twenty industrial workers performed repetitive tasks at three different levels of production standard time, normal, hard, and very hard. Work productiv...

[Purpose] This study investigated the variations in muscle fatigue, time to fatigue, and maximum task duration at different levels of production standard time. [Methods] Twenty subjects performed repetitive tasks at three different levels of production standard time corresponding to "normal", "hard" and "very hard". Surface electromyography was use...

[Purpose] This study investigated the effects of postural angle on back muscle activity during a computer task in aging women. [Subjects] Seventeen women ≥50 years old participated. [Methods] The participants were instructed to perform computer-related tasks for 20 minutes on a workstation that simulated typical office working conditions. Back post...

The scheduling problem in flexible manufacturing systems (FMS) environment with loop layout configuration has been shown to be a NP-hard problem. Moreover, the improvement and modification of the loop layout add to the difficulties in the production planning stage. The introduction of multi loading-unloading points and turntable shortcut resulted o...

This paper presents significant empirical evidence on the relationship between Advanced Manufacturing Technology (AMT) practices and sustainable environmental initiatives with the manufacturing capabilities of automotive SMEs in Malaysia. A cross-sectional survey is adopted in this study, which involves 83 Malaysian automotive SMEs. Two hypotheses...

This study is to measure and investigate the muscle contraction during lifting tasks activities with the effect of different loads, height, angle of twisting and lifting frequency. This study involved 14 male and female participants performed the lifting tasks with different weight loads of 10kg to 24kg into the height position of 70cm and 130cm at...

Future design for the elderly is undoubtedly important for their survival to live independently in this challenging world. Therefore to realize the mentioned design, an anthropometric database for Malaysian elderly population need to be developed. A total of 107 participants took part in the study which involved 61 females and 46 males with ages ra...

Traditional robotic work cell design and programming are considered inefficient and outdated in current industrial and market demands. In this research, virtual reality (VR) technology is used to improve human-robot interface, whereby complicated commands or programming knowledge is not required. The proposed solution, known as VR-based Programming...

In today’s highly rival market, an effective supplier selection process is vital to the success of any manufacturing system. Selecting the appropriate supplier is always a difficult task because suppliers posses varied strengths and weaknesses that necessitate careful evaluations prior to suppliers’ ranking. This is a complex process with many subj...