Past Research Projects of Ravindra Goonetilleke

Publications, Human Performance Laboratory


1. A Theory for Comfort and its Application in Product Design

Even though consumer products have been researched over a long period of time, research relating interface pressure and long term comfort is rather patchy. Spinal disc pressures and electromyography have been extensively used to determine discomfort. Researchers have also been limited by the lack of a viable operational definition of comfort, and designers have difficulty to design products right the first time for improved user comfort. Due to the many parameters encompassing the perception of comfort, the psychophysics of comfort has not really been a well explored concept and, is often defined as the absence of discomfort. Interface pressure related studies have suggested that contoured surfaces effectively increase areas, reducing interface pressures and thereby improving comfort. However, sensory theories tend to contradict this hypothesis. The primary intention of this study is the development of a theory for comfort and its application to consumer product design


2. Cultural Human-Computer Interfaces for the Chinese population

with Heloisa H.M. Shih

There is a well-known set of principles and guidelines to direct the design of user interfaces. However, the development of these guidelines was based almost solely on the experience and environment of the Western culture, mainly the United States and Europe. Although many aspects of computer interfaces may be considered universal, or culture-independent, others may be culture-department. For example, use of colour, use of context, sequencing pictures, etc., may have significant implications on graphical interfaces for the Chinese population. In this research, we challenge the existing User Interface Design guidelines systematically and scientifically with regard to their applicability to the Chinese population. We also identify popular metaphors of the Chinese culture, that could make the interfaces easier to learn and less error-prone. The expected outcome of this research is a set of guidelines for the Chinese language-based user interfaces, making possible a much needed addition to existing User Interface Design principles.

Applied Science Lab eye-tracking system for human-computer interfaces studies and design



3. Supervisory Training in Complex Control Tasks

With the advent of automation and advances in technology, the activities of the operator have shifted from those of an in-the-loop controller to those of an out-of-the-loop supervisor or monitor. Hence the concept of supervisory control poses a very important question with regard to training. If the operator is to be primarily a monitor rather than a controller, shouldn't the training also be done out-of-the-loop? Previous investigations have shown that out-of-the-loop training produces better optimization capabilities, but poor learning of system dynamics makes control difficult in emergency situations. The aim here is to create a supervisory training scheme that will give optimal performance during normal and emergency situations.


4. Development of a Universal Foot Sizing System

with Kwok-Leung Tsui

Traditionally, foot sizing is done by using a Brannock device for the measurement of length and width. However, from a mathematical viewpoint it is almost impossible to generate a foot form of 3-dimensions using a set of 2-dimensional measures of foot length and width. In addition, footwear manufacturers use at least four different shoe scales primarily for the U.S., U.K., European and the fourth being a metric measurement. On the flip side, these same manufacturers depend on up to thirty different measures to build a shoe last. Hence the mapping is clearly inadequate: two measures from the Brannock device to map 30 measures on the shoe last. So the question is very fundamental: Is length and width the basis for all other measurements or is there a better measurement(s) to represent the human foot? The problem at hand can be classically illustrated using the concept of basis vectors. In the past, the length and width were chosen to represent the human foot since they were easy to measure and were also perpendicular to each other. The orthogonal vectors were assumed independent and were used to represent the basis vector. This is the rationale for the research. The objective of the research is to elicit in mathematical terms, the basis vector or sizing system that best represents the human foot so that all 3-D measurements can be derived from the basis vector.

Foot Digitization using Science Accessories Corporation 3-D Sonic Digitizer



5. Dynamic Footwear Fit: Is It The Same As Static Fit?

Footwear fit is generally one of trial and error. Each individual may use a different size of shoe for a different application. The primary reason can be attributed to differences between static fit and dynamic fit. To investigate this mismatch, we propose to develop a running/walking simulator that will allow precise measurement of foot dimensions in dynamic conditions or as the foot moves during any activity. The apparatus will comprise of a piston under the heel with the forefoot fixed. An electric motor will drive the piston under the heel and will emulate the natural frequency of running or walking based on speeds of 5 min/km or 12.5 min/km. Stride distances and plantar flexion would be obtained from a treadmill measurement to simulate the foot impact frequency and piston stroke. Instrumentation on and around the foot will allow precise measurements of the foot during movement. The objective of the project will be to quantify the differences between static and dynamic foot conditions using statistical analyses.


6. Sports Ergonomics

Cricket is one sport where there is very little scientific research. We have designed and developed an innovative way to check the legality of bowling in cricket. On-going research is related to batting and bowling in cricket.



7. Comfort-Pressure Investigations

Comfort is a high selling point in today's commercial market. However, comfort-pressure studies have not been successful to generate new theories to improve product design. Using commercially available sensors and MEMS technology, we are currently investigating the relationship between comfort and pressure with special relevance to seats and footwear.

Foot-shoe interface pressure using the FSCAN pressure measurement system


Questions, comments or criticisms are welcome. Please email to: ravindra@ust.hk

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last updated October 30 2010