topauthor: Goonetilleke_R* : Human-Computer Interaction Bibliography Search

[1] Superiority of Freehand Pointing Product Design: PD1 -- Touch Screen / Senanayake, Ransalu / Goonetilleke, Ravindra S. Proceedings of the Human Factors and Ergonomics Society 2013 Annual Meeting 2013-09-30 p.1639-1642

doi 10.1177/1541931213571364

Link to HFES Digital Content

Summary: 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 for ballistic steering tasks, while movement time was affected by the type of device used in visually controlled steering tasks. It was also found that resting the forearm increased movement time. Subjective evaluations indicated that control is easier with freehand pointing. Considering both comfort and performance it appears that freehand pointing, when resting the forearm, is optimal for a touchscreen.

[2] Setting That Mouse for Tracking Tasks Ergonomics of Work with Computers / Senanayake, Ransalu / Goonetilleke, Ravindra S. DHM 2013: 4th International Conference on Digital Human Modeling and Applications in Health, Safety, Ergonomics, and Risk Management, Part II: Human Body Modeling and Ergonomics 2013-07-21 v.2 p.276-281

Keywords: Pointing devices; Mouse; Gain; Drury's Law; Steering Law

Link to Digital Content at Springer

Summary: 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 computer mouse. There were three levels of gain approximately equal to 2.3, 10, and 15. The experiment had 11 levels of difficulty (D/P) based on path width (P) and path length (D) and three trials for each combination of D and P. Performance was evaluated using movement time taken to traverse the path. The results showed that movement time is minimized, in feedback-controlled steering tasks, at a gain of around nine.

[3] Product Design and Emotion: Frameworks, Methods, and Case Studies Product Design: PD6 -- Product Design and Emotion / McLoone, Hugh / Jacobson, Melissa / Goonetilleke, Ravindra S. / Kleiss, James / Liu, Yili / McLoone, Hugh / Schütte, Simon Proceedings of the Human Factors and Ergonomics Society 2012 Annual Meeting 2012-10-22 p.1940-1941

doi 10.1177/1071181312561285

Link to HFES Digital Content

Summary: 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 world of affective or emotional design of products? 2) Method: What design research method(s) are used to measure emotional reactions to designs? 3) Case Study: What product design(s) exemplify the frameworks, methods, and/or otherwise highlight a successful product design? At the end of the session, attendees will have at least five frameworks, five research methods, and five case studies of exemplary products for inspiration in their work and research.

[4] Time use behavior in single and time-sharing tasks / Luximon, Yan / Goonetilleke, Ravindra S. International Journal of Human-Computer Studies 2012-05 v.70 n.5 p.332-345

Keywords: Complex control

Keywords: Hill-climbing

Keywords: Monochron/polychron

Keywords: Time use

Keywords: Control strategy

Keywords: Performance

Keywords: Task characteristics

Link to Article at sciencedirect

Summary: 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. Polychrons are people, who favor doing multiple tasks at the same time, while monochrons prefer doing tasks in series. In this study, the strategy, performance and workload of monochrons and polychrons were evaluated in a single and dual control tasks. The task difficulty and multiple task priority were independent variables. Results indicated that polychrons switched between two tasks more than monochrons and achieved better performance when the tasks were equally important and difficult. When the priority between the tasks was different, monochrons changed their emphasis to the more important task even though polychrons did not change their strategy as dramatically as the monochrons. In addition, monochrons indicated significantly higher workload and difficulty than polychrons. Results of this study can be important for the development of training programs of personnel involved in time-critical operations.

[5] Center of Pressure Variations in High-Heeled Shoes Product Design: PD3 - Product Design and Modeling / Weerasinghe, Thilina W. / Goonetilleke, Ravindra S. Proceedings of the Human Factors and Ergonomics Society 55th Annual Meeting 2011-09-19 p.1640-1643

doi: 10.1177/1071181311551342

Link to HFES Digital Content

Summary: 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 allowed the design parameters of a shoe to be investigated. The wedge angle and midfoot conditions were varied, and their effects were modeled with psychophysical relationships. The results show that perceived feelings are closely related to the location of the center of pressure.

[6] Thermal Properties of Reflective Helmet Exposed to Infrared Radiation Product Design: PD4 - Product Design, Investigation, and Assessment / Reischl, Uwe / Goonetilleke, Ravindra S. Proceedings of the Human Factors and Ergonomics Society 55th Annual Meeting 2011-09-19 p.1663-1665

doi: 10.1177/1071181311551346

Link to HFES Digital Content

Summary: 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 results illustrate the benefits offered by an aluminized reflective surface in attenuating IR radiation and the advantages of using a spacer harness system to minimize radiant heat transfer from the helmet to the head.

[7] Footbed Influences on Posture and Perceived Feel Posture and Motion Modeling / Weerasinghe, Thilina W. / Goonetilleke, Ravindra S. DHM 2011: 3rd International Conference on Digital Human Modeling 2011-07-09 p.220-227

Keywords: Posture; Footbed; Comfort; High-heels; Footwear

Link to Digital Content at Springer

Summary: 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 10 degree wedge angle at 50 mm and an 18 degree wedge angle at 75 mm have the highest perceived feel during standing. The corresponding postures were significantly different from the others tested, suggesting that a well-designed footbed is a necessary condition to feel comfortable and to maintain good posture.

[8] Designing Flight Information Displays for Quick Information Access: A Case Study of an International Airport COMPUTER SYSTEMS: CS3 -- Usability and Evaluation / Rodrigo, Asanka S. / Goonetilleke, Ravindra S. Proceedings of the Human Factors and Ergonomics Society 54th Annual Meeting 2010-09-27 v.54 p.586-589

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Summary: 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 of flight information. Seven potential grouping methods were tested. Search time depends on the layout of information (p < 0.001). Search was fastest when the information was arranged in the order of airline logo, airline name and arrival or departure time.

[9] The relationship between monochronicity, polychronicity and individual characteristics / Goonetilleke, Ravindra S. / Luximon, Yan Behaviour and Information Technology 2010 v.29 n.2 p.187-198

Link to Article at informaworld

Summary: 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 individual characteristics. Forty-eight Chinese participants were tested on their perception, memory, judgement, attention ability and cognitive style. They also performed a task that required search and calculation under three conditions of unpaced, paced and paced with sequencing. There were significant differences in the performance and strategy between monochronic and polychronic individuals in the selective attention test. Monochronic individuals focused their attention on the primary task and achieved higher performance. Polychronic individuals had somewhat better total performance in more than one task under time-constrained conditions. The results clearly indicate that an individual's time use behaviours ought to be considered in training and control scenarios to account for differences among people.

[10] The Pluses and Minuses of Obtaining Measurements from Digital Scans Advances in Digital Human Modeling / Goonetilleke, Ravindra S. / Witana, Channa P. / Zhao, Jianhui / Xiong, Shuping DHM 2009: 2nd International Conference on Digital Human Modeling 2009-07-19 p.681-690

Keywords: Scanning; foot; measurement; registration; alignment; brannock; width; girth

Link to Digital Content at Springer

Summary: 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 three different alignment methods of foot scans and their effects on ten different measurements. Variations among methods in capturing foot length are relatively small relative to arch length. The foot girths can be quite sensitive to the registration process depending on the complexity of the algorithms used. As expected, linear and girth measurements based on anatomical landmarks will always be independent of any registration process and are thus good ways to obtain repeatable measurements.

[11] Midfoot Shape When Standing on Soft and Hard Footbeds INDUSTRIAL ERGONOMICS: Slips, Trips, and Falls / Goonetilleke, Ravindra S. / Witana, Channa P. Proceedings of the Human Factors and Ergonomics Society 50th Annual Meeting 2006-10-16 v.50 p.1327-1331

Link to HFES Digital Content

Summary: 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 amount of cushioning on the support surface was changed, the plantar mid-foot sag changed by 5.0 mm. The results have important implications for footwear design as midfoot shapes in footwear are somewhat standardized and are not adjusted to account for the cushioning properties of the footbed. The mismatched deformations between feet and shoes as a result of design, structure and material used in the heel and forefoot regions of shoes can contribute to unwanted strain on the plantar fascia of the human foot.

[12] Time-related behaviour in multitasking situations ARTICLE / Zhang, Yan / Goonetilleke, Ravindra S. / Plocher, Thomas / Liang, Sheau-Farn Max International Journal of Human-Computer Studies 2005 v.62 n.4 p.425-455

Keywords: Monochronicity; Polychronicity; Multitasking; Process control

Link to Article at ScienceDirect

Summary: Researchers have classified differing time-related behaviours as Monochronicity (M) and Polychronicity (P). The objective of this study was to evaluate control strategy and control performance differences between M and P persons in a process control domain. Forty-two people participated in an experimental study. Time-related behaviour was evaluated using the Modified Polychronic Attitude Index 3 (M/P score) scale. Each participant was asked to monitor and control two processes at the same time using the Control Station software. A 2 (control system order)*5 (trials) factorial experiment was used. Performance was quantified using overall mean error and overall Root-Mean-Square (RMS) error. Control strategy was quantified using the number of switches between the two processes and the number of magnitude changes within each of the processes. Correlation and regression analyses showed that the M/P score was significantly correlated with the strategy variables and performance variables. When the participants were split into the three groups, M (M/P score greater than or equal to 1 and less than or equal to 3), neutral (M/P score between 3 and 5) and P (M/P score greater than or equal to 5 and less than or equal to 7), there were significant differences in the performance and strategy measures among the three groups. The strategy variables indicated that monochrons attempted to control the two processes serially, while polychrons controlled both processes somewhat simultaneously. The neutral group was in-between the M and P groups. The results also showed that the overall mean error and overall RMS error of polychrons were significantly smaller than that of the monochrons. Furthermore, there was no significant difference in the NASA-Task Load Index score between monochrons and polychrons, even though there were significant correlations between the M/P score and some of the scale dimensions' weightings. The results of this study can have important implications for the training and selection of personnel in multitask situations, such as industrial process control.

[13] A Linear Programming Model for Workstation Adequacy INDUSTRIAL ERGONOMICS: Practice-Oriented Session / Gupta, Avaneesh / Zhang, Mei / Goonetilleke, Ravindra S. Proceedings of the Human Factors and Ergonomics Society 48th Annual Meeting 2004-09-20 v.48 p.1383-1387

Link to HFES Digital Content

Summary: Workstation design can have a profound effect on an individual's health. Most product designs are based on a 5th percentile "reach" and a 95th percentile "clearance". These designs quite often fail to match a person's body measurements since the dimensions of each body link are not exactly the same xth percentile. Even with an adjustable workstation, the user has a dilemma as to what adjustment to make for each adjustable parameter as each adjustment depends on the previous adjustment and the potential number of adjustments is somewhat infinite. This paper focuses on a methodology to achieve a postural fit for a given workstation with an adjustable table, chair, and footrest. The least stressful and somewhat comfortable postures were first determined from the literature. Thereafter, a Linear Programming model was developed to capture these mappings as mathematical constraints and solved. The model was validated with an adjustable workstation and a few participants.

[14] Visual search strategies and eye movements when searching Chinese character screens / Goonetilleke, Ravindra S. / Lau, W. C. / Shih, Heloisa M. International Journal of Human-Computer Studies 2002 v.57 n.6 p.447-468

Summary: Most visual search studies have been restricted to alphanumeric stimulus materials. Research related to scanning patterns of Chinese characters is sparse. This study is an attempt to understand the differences and similarities in visual search of Chinese characters having a varying degree of complexity among Hong Kong Chinese, Mainland Chinese and Chinese reading non-Chinese people. Eighteen participants were tested on Chinese character screens with three layouts (row, column, and uniform separation) and two word complexities (high and low). The 18 participants comprised six Hong Kong Chinese, six Mainland Chinese and six non-native Chinese readers. Performance data and eye movement data were recorded. The percent correct and search time were the two performance measures. A new measure, called HV-ratio was developed to characterize eye movements. The results show that Hong Kong Chinese use predominantly horizontal search patterns while the Mainland Chinese change their search pattern depending on the layout presented. Non-native Chinese readers, on the other hand, do not seem to show any preference on scanning strategy for a given layout. Word complexity did not show any significant effect on search time. Potential reasons for these differences and design implications are discussed.

[15] Customer Needs in Web Based Interaction: A Macro View of Usability / Goonetilleke, R. S. / Duffy, C. / Jacques, D. Proceedings of the Ninth International Conference on Human-Computer Interaction 2001-08 v.1 p.365-369

[16] Effects of training and representational characteristics in icon design / Goonetilleke, Ravindra S. / Shih, Heloisa Martins / On, Hung Kai / Fritsch, Julien International Journal of Human-Computer Studies 2001 v.55 n.5 p.741-760

Summary: Icons are a very important component of graphical user interfaces. However, icon design is still predominantly artistic in nature and as a result icon selection is generally based on usability evaluations after a set of alternative icons are developed. This process tends to be time-consuming and costly. In this research, we address the issues of what should be depicted in an icon, given the function it should represent, and how training affects the performance of novice users when using an iconic interface. A set of 36 concrete icons (12 functions) were selected and tested with a total of 30 participants. The experimental results indicate that complete representations are generally superior for both untrained and trained participants. Results also show that trained participants had shorter response times when compared to untrained participants. Further analysis suggests that ambiguity, uniqueness and dominance are three important aspects to consider when designing and developing icons. Applications of this research include the design of appropriate icons for graphical user interfaces prior to usability testing and the importance of a short training period to illustrate the composition of an icon in an effort to improve the mental model associated with each design.

[17] The Quality of Footwear Fit: What we know, don't know and should know 2: MULTIPLE-SESSION SYMPOSIA: Quality in Design [Research] / Goonetilleke, Ravindra S. / Luximon, Ameersing / Tsui, Kwok L. Proceedings of the Joint IEA 14th Triennial Congress and Human Factors and Ergonomics Society 44th Annual Meeting 2000-07-30 v.44 n.2 p.515-518

Link to HFES Digital Content

Summary: Even though fit ranks as one of the most important considerations in the purchase of a shoe, the quality of fit has no metric and is hence poorly assessed. Manufacturers, retailers, and customers tend to use trial and error techniques to improve footwear fit. This approach is rather cumbersome and very unscientific. In this paper, we present a methodology to assess and thereby quantify footwear fit so that comfort can be predicted and consequently improved lasts and shoes can be produced that match different shapes of feet.

[18] Do Existing Menu Design Guidelines Work in Chinese? Organizational and Social Issues / Shih, H. M. / Goonetilleke, R. S. Proceedings of the Seventh International Conference on Human-Computer Interaction 1997-08-24 v.1 p.161-164

[19] Perceived Differences in Running and Walking Shoes CONSUMER PRODUCTS: Culture, Perception, and People in Product Design [Lecture] / Goonetilleke, Ravindra S. / Cann, Michael T. Proceedings of the Human Factors and Ergonomics Society 39th Annual Meeting 1995-10-09 v.1 p.336-340

WARNING: THE ABSTRACT OF THIS ENTRY HAS NOT BEEN VALIDATED

Summary: Designers rely heavily on the past sales history of a particular shoe when attempting to make decisions regarding shoe characteristics of future shoes. Cushioning devices made of air, "super" gases, energy return rubber, and gel's have become popular. However, the question that needs to be asked is whether these devices are truly functional or whether they are primarily of aesthetic value. Shoe qualities such as cushioning, comfort, stability, shock absorption, and energy return play an important role during athletic activity. It is also known that the above mentioned characteristics have significant interactions with each other. Hence it is important to know the relevance of these interactions when designing shoes for a particular activity. The primary goal of this study was to investigate the interaction and relevance of shoe properties during running and walking. Four specially fabricated shoes were used in the study. The results indicate the following: Heel cushioning and shock absorption play an important role in the overall cushioning of a midsole. Runners perceive shoe-heel cushioning somewhat differently from those who use shoes for walking. Heel cushioning during running seems to be influenced by shock absorption, stability and possibly rebound. Heel cushioning during walking seems to be influenced by shock absorption and possibly rebound. Hence a good running shoe can in most cases satisfy the biomechanical needs during walking.

[20] What Does an Operator Need to Learn? TRAINING: Training Effectiveness in Industry [Symposium] / Goonetilleke, Ravindra S. / Drury, Colin G. / Sharit, Joseph Proceedings of the Human Factors and Ergonomics Society 39th Annual Meeting 1995-10-09 v.2 p.1284-1288

WARNING: THE ABSTRACT OF THIS ENTRY HAS NOT BEEN VALIDATED

Summary: Using a simulated geosynchronous satellite relocation task, three types of training schemes, namely, in-the-loop, out-of-the-loop, and a composite of these two methods were evaluated. Verbal protocols in addition to performance and strategy measures were used to understand learning in this complex task. The results point toward an amplitude hypothesis of learning where two distinct phases are evident. In the first, large amplitude fluctuations exist due to the lack of a good mental model of the system dynamics. In the second, the amplitude fluctuations are low, and the performance improvements are dramatic suggesting the end of the mental model development phase and a gradual improvement in the system optimization parameters leading to the traditional power law learning curve.
Based on the results, it may be concluded that to learn a system or process well, the operator needs to:

1. Develop a good mental model of the system dynamics to minimize the large fluctuations in performance, and
2. Understand the optimization criteria to improve performance with low amplitude variations.

[21] Evaluation of Control Strategies in a Complex Space-Vehicle Control Task: Effects of Training Type III.11 Evaluation and Analysis 2 / Goonetilleke, Ravindra S. / Drury, Colin G. / Sharit, Joseph Proceedings of the Sixth International Conference on Human-Computer Interaction 1995-07-09 v.III. Analysis, Design and Evaluation in Human-Computer Interaction p.311-316

Summary: The fundamental differences in operator control strategies in a complex task were evaluated in two training scenarios: in-the-loop training and out-of-the-loop training. Verbal protocols and performance measures revealed four types of complex control mechanisms dependent upon these two training approaches. The four types were display based control, open loop input control, closed loop input control, and an input-display control mix. Performance differences favored in-the-loop training, and led to the development of an open loop input control strategy. The overall results indicate that performance improvements may be achieved with operator training on the system dynamics and optimization aspects rather than operator training directed only at the optimization aspects. A "sitting by Nellie" approach such as watching an expert or watching an algorithm perform a task may be disastrous if the system dynamics are poorly understood. This study also suggests how operator strategies can be effectively used to design user-friendly aids which improve operator performance in complex control tasks.

[22] Contact Area Effects on Discomfort INDUSTRIAL ERGONOMICS: Ergonomic Applications II [Lecture] / Goonetilleke, Ravindra S. / Eng, Timothy J. Proceedings of the Human Factors and Ergonomics Society 38th Annual Meeting 1994-10-24 v.1 p.688-690

Summary: Most "ergonomic" products attempt to adopt a uniform force distribution strategy to improve comfort. The rationale being that force distribution over a large area reduces pressure and thereby enhances user comfort. However, sensory literature alludes to the concept of spatial summation, i.e. greater sensation by stimulating a larger surface area. Hence spatial summation would tend to suggest a greater discomfort when forces are applied over large surface areas. This study reports the effect of surface area on maximum discomfort causing pressure or maximum pressure tolerance (MPT). Two circular probes of different cross sectional area were used to stimulate the skin surface. The mean MPT with a probe of 5mm diameter was 3.3 times higher than the MPT with a probe of 13mm diameter. These findings suggest the following:

Perceived discomfort and contact area seem to have a "U-relationship" above a critical force value. Traditional thinking of distributing forces is successful only in the first half of the U-curve or with forces below the critical value. The section with the monotonically increasing relationship between disconcert and contact area (i.e., second half of U) may not be seen at very low forces or forces below the critical value.
"High" pressures in concentrated areas may cause less discomfort than "moderate" pressures over a larger area.
The critical or threshold pressure to induce discomfort is force and contact area dependent.

[23] Shoe Cushioning and Related Material Properties CONSUMER PRODUCTS: Product Applications / Goonetilleke, Ravindra S. / Himmelsbach, Jennifer A. Proceedings of the Human Factors Society 36th Annual Meeting 1992-10-12 v.1 p.519-522

Summary: This study investigated the effect of dynamic material properties on the Perceived Level of Cushioning (PLC) in shoes. An Impact Tester was used to characterize the material properties. Three pairs of shoes were used in the two experiments conducted. Experiment 1 was aimed at establishing the effects during standing while experiment 2 was an attempt to relate the effects during walking. A 7-point scale was used to rate PLC. The results showed that during standing, PLC may be related to stiffness of the material, compression, and the time to reach maximum deceleration. However, during walking, PLC appears to be related to the maximum deceleration as measured by the Impact Tester.