Ravindra S Goonetilleke

Khalifa University | KU · Department of Engineering Systems and Management

The perceived differences between comfortable and uncomfortable shoes and the fit preferences in the different regions of ladies' shoes were explored. Twenty Hong Kong Chinese females participated in the study. Each participant wore and rated the different aspects of their own comfortable and uncomfortable shoes. The Wilcoxon signed rank tests show...

Although the subjective workload assessment technique (SWAT) has been widely used, it has two main problems: it is not very sensitive for low mental workloads and it requires a time-consuming card sorting pretask procedure. In this study are presented five variations of SWAT in an effort to overcome the limitations. Four of the variants used the co...

A shoe wearer's comfort is related to the shape of the footbed of a shoe. Even though the footbed shape is important in footwear design, there exists no methodology to evaluate the existing guidelines used in last making. Thirty-two females participated in an experiment where heel seat length, heel seat inclination and heel height were investigated...

The medial longitudinal arch of the foot is important because it helps protect the foot from injury. Researchers have developed many measures to quantify the characteristics of the arch, and there is ongoing debate about the suitability of these different metrics. This article compares the various measures related to the foot arch, including a new...

With the increasing complexity of control rooms and the information explosion, effective multitasking is now desired. Monochronicity and polychronicity, which describe a person's ability to do one thing and many things at a time, respectively, have been studied for a long time. However, it is not clear these abilities are related to various individ...

In the dynamic world of fashion, high-heeled footwear is revered as a symbol of style, luxury and sophistication. Yet, beneath the facade of elegance of classy footwear lies the harsh reality of discomfort and pain. Thus, this study aims to investigate the influence of wearing high-heeled shoes on the sensation of pain across different body regions...

With the rapid improvements in drone technology, there is an increasing interest in distal pointing to diffuse drones. This study investigated the effect of depth on distal pointing when the hand does not traverse the entire distance from start to target so that the most suitable mathematical model can be assessed. Starting from the Fitts paradigm...

Objective With the rapid improvements in drone technology, there is an increasing interest in distal pointing to diffuse drones. This study investigated the effect of depth on distal pointing when the hand does not traverse the entire distance from start to target so that the most suitable mathematical model can be assessed. Background Starting fr...

Purpose: The purpose of this article is to examine the Critical Failure Factors (CFFs) linked to various types of Process improvement (PI) projects such as Kaizen, Lean, Six Sigma, Lean Six Sigma and Agile. Proposing a mitigation framework accordingly is also an aim of this study. Design/ Methodology/ Approach: This research undertakes a systemati...

Purpose The purpose of this study is to examine the critical failure factors (CFFs) linked to various types of process improvement (PI) projects such as Kaizen, Lean, Six Sigma, Lean Six Sigma and Agile. Proposing a mitigation framework accordingly is also an aim of this study. Design/methodology/approach This research undertakes a systematic lite...

With the emergence of enormous amounts of data, numerous ways to visualize such data have been used. Bar, circular, line, radar and bubble graphs that are ubiquitous were investigated for their effectiveness. Fourteen participants performed four types of evaluations: between categories (cities), within categories (transport modes within a city), al...

Research on traffic accidents have acknowledged that human error is the leading cause of road accidents around the world. In the UAE, those aged between 18 and 30 years are involved in the most accidents. As a result, this study examines the perception, attitude and driving behavior of young adults in the UAE. Virtual Reality (VR) was used to exami...

In multi-axis fused deposition modeling (FDM) printing systems, support-free curved layer fabrication is realized by continuous transition of the printer nozzle orientation. However, the ability to print 3D models with complex geometric (e.g., high overhang) and topological (e.g., high genus) features is often restricted by various manufacturabilit...

Designing products and services to fit human needs, wants and lifestyle require meaningful data. With Industry 4.0 and the internet of things, we have many ways to capture data using sensors and other means. InfraRed (IR) cameras are quite ubiquitous, especially for screening illness and wellness. They can provide a wealth of data on different obje...

The worldwide population is aging, even though more and more elderly people are living independently and alone. Moreover, pandemics such as COVID-19 are putting enormous pressure in health care systems all around the world. To deal with the growing elderly population and health care challenges, there is an emerging focus on technology and IT produc...

Persons exposed to solar heat radiation in hot and dry climates are at increased risk of heat illnesses. Clothing can reduce such exposure. The effectiveness of clothing to reduce such heat loading depends on the ability of the fabric to reflect this heat radiation. However, incomplete reflection results in fabric heating which will heat the body b...

Managing the workers’ health and safety faces many challenges due to the dependency on human interactions especially when it comes to human monitoring and detecting nonconformance. Conventionally, the input to HSE making decisions is collected from the worker himself or by an HSE officer making it mostly biased and hard to communicate. The team pro...

In the past only health care professionals wore facemasks daily, but in recent times almost all citizens of many countries are expected to wear facemasks to reduce infection at work and in public. Because of SARS and now COVID-19, facemasks have become an essential personal protective equipment to fight against infectious disease. Frequent use of m...

This book presents the proceedings of the Joint Conference of the Asian Council on Ergonomics and Design and Southeast Asian Network of Ergonomics Societies (ACED SEANES), held on December 2-4, 2020. By highlighting the latest theories and models, as well as cutting-edge technologies and applications, and by combining findings from a range of disci...

This book brings together experts from different areas to show how creativity drives design and innovation in different kind of businesses. It presents theories and best practices demonstrating how creativity generates technological invention, and how this, combined with entrepreneurship, leads to business innovation. It also discusses strategies t...

This book reports on cutting-edge findings and developments in physical, social and occupational ergonomics. It covers a broad spectrum of studies and evaluation procedures concerning physical and mental workload, work posture and ergonomic risk. Further, it reports on significant advances in the design of services and systems, including those addr...

Aimed movement is ubiquitous and has been extensively investigated. However, little research exists when the hand movements are incompatible with eye movements such as when viewing through a mirror or when performing laparoscopic surgery. An experiment was designed to investigate how individuals perform under one-dimensional and two-dimensional inv...

Design thinking is a mindset to find a solution for a real need using an iterative method. Its fundamental philosophy is to empathize and reframe a problem so that one can innovate faster using systematic methods. In this study, we illustrate the use of design thinking to enhance the life of older people. A total of forty students from two universi...

This book reports on cutting-edge findings and developments in physical, social and occupational ergonomics. It covers a broad spectrum of studies and evaluation procedures concerning physical and mental workload, work posture and ergonomic risk. Further, it reports on significant advances in the design of services and systems, including those addr...

This book brings together experts from different areas to show how creativity drives design and innovation to allow the integration of a wider spectrum of topics related to engineering design, industrial design and ergonomics in design. It presents theories and best practices demonstrating how creativity generates technological invention, and how t...

The mouse, being the major means of inputting and controlling data on a computer, should be set right for best performance. Mouse gain, defined as the ratio of the movement distance on the computer screen to the movement distance of the mouse, controls the movement time when both speed and accuracy are important. Reported optimum gain values vary w...

Most anthropometric studies generally relate to one chosen population. We wanted to assess the variations among different age groups to get a better understanding of the changes to foot shape so that footwear can accommodate these changes satisfactorily. Footwear are not differentiated between adults and elderly, even though there are footwear for...

This book reports on the state of the art in physical ergonomics and addresses the design of products, processes, services, and work systems to ensure they are productive, safe, and enjoyable for people to use. The human body’s responses to physical and physiological work demands, strain injuries from repetition, vibration, force, and posture are t...

This book reports on the state of the art in physical ergonomics and is concerned with the design of products, process, services, and work systems to assure their productive, safe, and satisfying use by people. With focus on the human body's responses to physical and physiological work demands, repetitive strain injuries from repetition, vibration,...

The objective was to develop a methodology to assess Pressure Discomfort Thresholds (PDT), Pressure Pain Thresholds (PPT), and tissue stiffness on the plantar surface of the foot. Ten male and ten female participants volunteered for the study. Foot landmarks were used to create a standardized grid-type template of 95 points. For each test point, PP...

Manual load carriage continues to be a major contributor of musculoskeletal injury. This study investigates the physiological and subjective effects of an on-hip load-carrying belt (HLCB) during bimanual anterior load carriage. Fifteen healthy male participants walked on a level ground treadmill at 4.5 km/h for 5 min carrying 5, 10 and 15 kg loads...

Use of touch-screen-based interactions is growing rapidly. Hence, knowing the maneuvering efficacy of touch screens relative to other pointing devices is of great importance in the context of graphical user interfaces. Movement time, accuracy, and user preferences of four pointing device settings were evaluated on a computer with 14 participants ag...

Protective clothing is frequently used to provide safety and comfort for persons exposed to various temperature environments. Water absorbed by clothing can significantly influence the heat transfer characteristics of the clothing material. Understanding the dynamics of evaporative fabric cooling is important in the development of new garments. To...

This study aims to examine the influence of video type (commercial video vs. instructional video) and three cultural/individual difference factors (location: Hong Kong vs. Malaysia; education background: engineering/science vs. non-engineering/science; experience of using touchless technology: yes vs. no) on an individual’s behavioral intention to...

This book reports on the state of the art in physical ergonomics and is concerned with the design of products, process, services, and work systems to assure their productive, safe, and satisfying use by people. With focus on the human body's responses to physical and physiological work demands, repetitive strain injuries from repetition, vibration,...

Somatosensory technology is an emerging technology used in applications such as home entertainment, medical and healthcare. It can track human hand movement and enable users to interact with digital devices or physical environment by using hand gesture(s). Effectiveness of somatosensory technology is determined by the compatibility between the tech...

Targeting and tracking in graphical user interfaces have been widely studied, but attempts to model targeted-tracking are few. Targeted-tracking is essentially a two component task of tracking followed by targeting, where either or both components may dominate depending on the levels of difficulty in each component. The applicability of an empirica...

This study investigated the distribution of movement time (MT) and submovement time as a function of Fitts’ index of difficulty (ID) to help understand the underlying mechanisms of Fitts’ law. Many previous studies have shown that movements in such a task can be broken into a series of submovements, but have not been able to account for the variati...

Current models for targeted-tracking are discussed and shown to be inadequate as a means of understanding the combined task of tracking, as in the Drury's paradigm, and having a final target to be aimed at, as in the Fitts' paradigm. It is shown that the task has to be split into components that are, in general, performed sequentially and have a mo...

There is a possibility that computer mice may be replaced with eye-gaze or touchscreen technologies. Hence, it is imperative that we investigate the effect of the type of input device in conditions having lateral constraints. A set of tracks with different levels of difficulty were tested. The type of device had little influence on movement time fo...

A pointing device plays an important role in human-computer interaction. The computer mouse is a convenient device for both pointing and steering. The literature related to the effect of mouse gain on steering tasks is scarce. An experiment was conducted with 10 participants and each participant was asked to traverse a constrained path using a comp...

Unlabelled: The optimal force distribution to minimise pain or discomfort at the foot-shoe interface is still not known. Most shoe-related products attempt to distribute the load uniformly without much consideration to the bony and soft tissue regions. An experiment was conducted to first determine the pressure pain threshold (PPT) and tissue defo...

Although we now have sophisticated algorithms and techniques for determining the shapes and sizes and for matching the fit between shoes and feet, few, if any, of the books currently available cover these new technologies until now. Bringing together high-quality and state-of-the-art contributions from designers, biomechanists, ergonomists, enginee...

Successful product design meets or exceeds the emotional needs of users, beyond utility and quality. Likewise, successful product design applies the knowledge of aesthetics, beyond technologies, features, and ease of use. This Discussion Panel will offer three topics by each speaker to the audience: 1) Framework: What framework(s) describe the worl...

The psychophysical relationship between the magnitude of pressure on thirteen test locations of twenty healthy subjects' feet with four probe areas at three indentation speeds and the corresponding perceived sensations were analyzed. The dependency of pressure pain thresholds (PPT) on area, A, and speed, v, can be mathematically modeled in the form...

Human errors in aviation, process plants and other critical industries can result in dire consequences and hence it is essential to understand the operator behavior and task characteristics in order to improve task performance and safety. The time available and how it is used by the operator are important factors in multi-task situations. Polychron...

Path length (A), path width (W) and movement direction (θ) are identified as the main factors affecting visually-controlled movement times in linear paths. Effects of A and W are well described by Drury's (19714. Drury , C. G. 1971. Movements with lateral constraint. Ergonomics, 14(2): 293–305. [Taylor & Francis Online], [PubMed], [Web of Science...

This study was aimed to determine the effects of direction and path length on movement time when traversing a constrained path of width, W, in a mouse tracking task. Tracking within constrained paths has been demonstrated to hold in many applications. Movement time and velocity of movement have shown very similar relationships, possibly because of...

The existing methods for automatic girth measurement are primarily based on 3D point cloud or its generated surfaces, without considering limbs' elasticity and thus the interactive deformation during manual measurement. Taking human foot as example, we propose a new method to simulate manual girth measurement using 3D triangular mesh and mass-sprin...

Footwear have been evaluated mostly using commercially available products, while some researchers have used custom shoes. Hence, the understanding of the effects of various parameters of a shoe is quite limited. The footbed simulator invented in recent years allows a range of parameters to be studied in quiet standing. It can be used to evaluate pe...

The thermodynamic properties of a model infrared heat reflective helmet were evaluated using an advanced thermal manikin technology. The aluminized model helmet was tested for infrared (IR) radiation attenuation properties. Total manikin heat gain and changes in surface temperature were documented for controlled IR radiation exposure levels. The re...

The way in which a person’s foot contacts a shoe surface can have short-term and long-term effects on the whole body. Most previous research on footwear has been carried out using commercially available shoes, and as a result the surface of the shoe with which the foot interacts has not been systematically investigated. A recent invention has allow...

A novel region growing algorithm is proposed for triangular mesh recovery from scattered 3D points. In our method, the new principle is used to determine the seed triangle considering both maximum angle and minimum length; the open influence region is defined for the active edge under processing; positional element is added into the criterion to ch...

Past studies have evaluated body postures when wearing high-heeled shoes. However, the effects of the various parameters that give the footbed its shape have not been investigated. This study determined the perceived feel and the associated postures with the different types of footbed shapes at two heel heights of 50 and 75 mm. Results show that a...

The right fit and point-of-sale comfort are primary factors when purchasing footwear (Cheskin 1987; Chong and Chan 1992; McEvoy 1996; Au and Goonetilleke 2005). Among 420 European consumers, it has been reported that 51.5% of males and 58.8% of females had fit-related issues with footwear (Piller 2002). Ill-fitting footwear contribute toward discom...

Solar heat radiation can impose significant heat stress on employees performing outdoor tasks. A prototype infrared reflecting vest was developed to offer protection to agricultural workers and constructions workers who are exposed to high levels of outdoor solar radiation. The prototype vest was tested using a laboratory based thermal manikin expo...

Information related to reliable values of discomfort thresholds can help to improve the designs of various products. This study aimed to investigate the measurement reliabilities associated with pressure thresholds, while determining the effects of stimulus characteristics (stimulus area, indentation speed) of the human foot. An indentation apparat...

A psychophysical study was conducted to determine the ideal and acceptable foot-shoe allowances for widths and girths using an in-shoe simulator. Participants wore the in-shoe simulator product, walked, and rated the various regions of the foot. The ratings together with the foot scans were used to determine the ideal fit. The results of the signal...

A method and kit of parts for measuring the comfortable shape of a foot for a person. The kit comprises front and rear platforms of adjustable height and a supporting surface for accommodating the plantar surface of a foot extending between said platforms. The aforementioned components can be adjusted to various settings with a view to determining...

An ergonomic methodology has been designed and developed to evaluate the legality of bowling actions in cricket. This paper describes the methodology and a case study related to an international cricket player with an unorthodox bowling action. Objective measurements were used to evaluate the action. An electrogoniometer and a force-sensing resisto...

Increased air travel has made the provision of the optimal amount of information to travelers a necessity. Flight information is shown on electronic or mechanical display boards, but finding the required information can take some time depending on the display layout and content. This paper investigates the information configuration for quick access...

The mechanical properties of human foot tissue in vivo as well as discomfort and pain thresholds are important for various applications. In this study, an apparatus for measuring the discomfort and pain thresholds and the mechanical properties of human tissues is presented. The apparatus employs a stepper motor that controls the indentation speed,...

The psychophysical relationship between the magnitude of pressure on thirteen test locations of twenty healthy subjects' feet with four probe areas at three indentation speeds and the corresponding perceived sensations were analyzed. The dependency of pressure pain thresholds (PPT) on area, A, and speed, v, can be mathematically modeled in the form...

Three-dimensional point cloud data of a foot are used to determine the critical dimensions for making custom footwear. However, automatic and accurate measurement of dimensions, especially girths, is an issue of concern to many designers and footwear developers. Existing methods for measuring girths are primarily based on points or generated triang...

A method and apparatus for determining the comfortable footbed shape for a person. The apparatus comprises a rear platform for supporting the rear of a foot, a front platform for supporting a forefoot, the height of at least one of said front and rear platforms being adjustable relative to the height of the other one of said platforms and fixable a...

This study introduces a turning function based technique to classify foot outlines. Foot scans from ten males and ten females were obtained using a laser scanner. The similarities among the different foot shapes were assessed based on the Euclidean distance between turning functions. Thereafter, average linkage clustering was used to classify the d...

Background: The medial longitudinal arch of the foot is important because it helps protect the foot from injury. Researchers have developed many measures to quantify the characteristics of the arch, and there is ongoing debate about the suitability of these different metrics. This article compares the various measures related to the foot arch, incl...

Footwear comfort is primarily determined by the fit between the foot and the shoe. Foot deformations that cannot be accommodated by the flexibility of (lie material of the shoe upper have to be dealt with by other adaptive means The major purpose of this Study was to determine foot deformations using nine foot dimensions-foot length, arch length, f...

Digital scanners are commonplace and are used in many different applications to obtain three-dimensional shapes and linear and circumferential measurements. Even though scanners can be highly accurate, measurements obtained from scanners can vary depending on how an object is scanned, aligned and processed. In this study, we examined the effect of...

Even though manual tracking performance has been extensively investigated, there is little or no research related to the lower limit of temperature for unimpaired tracking performance. This study sought to obtain temperature limits while investigating the effect of hand-skin temperature on manual tracking. Eighteen subjects participated in a within...

In this study, two psychophysical models are proposed to predict perceived footwear fit with consideration of foot-shoe dimensional differences in the toe, metatarsophalangeal joint (MPJ) and mid-foot regions. A third-degree polynomial was constructed to predict the preference rating on a 7-point Likert scale from perceived footwear fit (5-point sc...

For many years, medical personnel have alluded to the health hazards of high-heeled shoes. However, fashion tends to override pain, no matter how dire the consequences may be. This led us to ask if high-heel shoes can be comfortable. Our study clearly shows that the design parameters of a shoe significantly influence the perceived feeling of a high...

In this paper, we propose a model and a solution procedure to minimize the cost associated with mass customizing consumer products in the presence of multivariate constraints. Three algorithms based on enumeration, steepest descent and Lagrange relaxation are used to solve the non-linear optimization problem and their performance is evaluated with...

Objective: Even though pressure on feet is generally unavoidable and undue pressure on some regions have been widely accepted as the major source of foot discomfort, pain and problems, there is little understanding of related human perceptions. The purpose of this study is two-folded: (1) to evaluate the reliability of a developed indentation appar...

A study of the shooting accuracy of three groups of pistol shooters is reported. The groups included (i) experienced gas pistol shooters; (ii) persons with experience in video shooting games; and (iii) persons with no shooting experience. The viewing time was varied in the tests. The results showed that experience had a significant effect on the me...

The application of foot anthropometry to design good-fitting footwear has been difficult due to the lack of generalised models. This study seeks to model foot dimensions so that the characteristic shapes of feet, especially in the midfoot region, can be understood. Fifty Hong Kong Chinese adults (26 males and 24 females) participated in this study....

Orthotics and other types of shoe inserts are primarily designed to reduce injury and improve comfort. The interaction between the plantar surface of the foot and the load-bearing surface contributes to foot and surface deformations and hence to perceived comfort, discomfort or pain. The plantar shapes of 16 participants' feet were captured when st...

Two experiments are reported with the aim of determining the effect of pen shape and size on two different types of task: drawing and writing. Experiment 1 attempted to determine the optimum shape and size of shank for ball-point pens used to perform an accurate drawing task. Twenty-seven participants used a total of nine different pens. Drawing pe...

Good fitting footwear requires matching not just the linear dimensions of feet but their girths as well. Footwear fitters have been using manual measurements for a long time, but the development of computerized techniques and scanner technologies have now made automatic determination of different foot dimensions feasible. The resistance to using su...

An approach is proposed for partial surface reconstruction from point cloud using RBF. Traditionally RBF based shape approximation method is used for entire object, but in many applications only partial part of the points needs to be reconstructed. Our method first transforms the partial point cloud with PCA, then generates off-surface points by pl...

Waterproof boots such as Wellingtons are commonly used by agricultural workers all over the world. Since this type of boot lacks laces to adjust the fit along the shoe, the design of the boot has to consider the foot height dimension besides the foot length and width dimensions. This study aims to model the height dimension of Chinese feet, so that...

Algorithms are proposed to automatically locate the foot anatomical points from scanned 3D point data based on a novel method that uses the pternion poin t for foot alignment, whereby variations in the diffe rent dimensions are minimized. The detected foot malleo li and arch point are used to classify the foot type. Based on the automatically detec...

In this study, the plantar shape of the midfoot was determined when the participants were standing on three different surfaces. Foot impression castings of sixteen participants were made when they were standing on a custom-made device. These castings were laser scanned in order to quantify the shape differences. The results showed that, when the am...

An approach to automatic foot measurement using 3D scanned data is proposed in this paper. The proposed approach was evaluated through comparisons of simulated measurements (SM) of eleven male and nine female participants with manual measurements (MM) and with the output of a commercially available automated foot measuring system (CP). The registra...

With the popularity of mobile devices, designing a keyboard for users who can only operate with a pointer or the eyes is a challenging task. In this paper we present a methodology and keyboard designs that attempt to optimize the key arrangement so that movement time, as defined by Fitts’ law, is minimized. Numerical simulations show that the prese...

This study is an attempt to model the midfoot height of adult females. The right feet of 24 Hong Kong Chinese females were laser scanned. The midfoot heights were then determined at intervals of 1.2 mm. These heights showed a significant relationship with normalized length along the foot. The fitted model had R 2 = 0.937 and has important implicati...

Two methods to generate an individual 3D foot shape from 2D information are proposed. A standard foot shape was first generated and then scaled based on known 2D information. In the first method, the foot outline and the foot height were used, and in the second, the foot outline and the foot profile were used. The models were developed using 40 par...

The control strategy and control performane differences between monochronicity (M) and polychronicity (P) persons in a process control domain were evaluated. The time related behavior was evaluated using the modified polychronic attitude index 3 (M/P score). Performance was quantified using overall root-mean-square (RMS) error. Control strategy was...