The mass customization decade: An updated review of the literature

Evaluation of mental workload with a combined measure based on physiological indices during a dual task of tracking and mental arithmetic

: The intent of this paper is to provide the reader with an overview of the mental workload literature. It will focus on other state-of-the-art surveys with reference to some specific reports of the practical application of mental workload measurement. The surveys will be limited to those in English. Manzey reportedly provides a review of psycho-physiological methods in German; a comparable, recent review in English was not found although a NATO RTO report (Wilson 2004, pp. 64-65 and Chapter 8) provides some guidance in this respect. Appendix 1 lists a search for references to workload measurement techniques using the GOOGLE search engine. The intent is to give the reader an appreciation of where work has been focused, or at least as reported on the Internet.

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A Review of the Mental Workload Literature

This paper explores the interaction possibilities enabled when the barrel of a digital pen is augmented with a multi-touch sensor. We present a novel multi-touch pen (MTPen) prototype and discuss its alternate uses beyond those of a standard stylus, such as allowing new touch gestures to be performed using the index finger or thumb and detecting how users grip the device as a mechanism for mode switching. We also discuss the hardware and software implementation challenges in realizing our prototype, and showcase how one can combine different grips (tripod, relaxed tripod, sketch, wrap) and gestures (swipe and double tap) to enable new interaction techniques with the MTPen in a prototype drawing application. One specific aim is the elimination of some of the comfort problems associated with existing auxiliary controls on digital pens. Mechanical controls such as barrel buttons and barrel scroll wheels work best in only a few specific hand grips and pen rotations. Comparatively, our gestures can be successfully and comfortably performed regardless of the rotation of the pen or how the user grips it, offering greater flexibility in use. We describe a formal evaluation comparing MTPen gestures against the use of a barrel button for mode switching. This study shows that both swipe and double tap gestures are comparable in performance to commonly employed barrel buttons without its disadvantages.

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Grips and gestures on a multi-touch pen

Most occupational tasks involve some level of mental/cognitive processing in addition to physical work; however, the etiology of work-related musculoskeletal disorders (WMSDs) due to these demands remains unclear. The aim of this study was to quantify the interactive effects of physical and mental workload on muscle endurance, fatigue, and recovery during intermittent work. Twelve participants, balanced by gender, performed intermittent static shoulder abductions to exhaustion at 15, 35, and 55% of individual maximal voluntary contraction (MVC), in the absence (control) and presence (concurrent) of a mental arithmetic task. Changes in muscular capacity were determined using endurance time, strength decline, electromyographic (EMG) fatigue indicators, muscle oxygenation, and heart rate measures. Muscular recovery was quantified through changes in strength and physiological responses. Mental workload was associated with shorter endurance times, specifically at 35% MVC, and greater strength decline. EMG and oxygenation measures showed similar changes during fatigue manifestation during concurrent conditions compared to the control, despite shorter endurance times. Moreover, decreased heart rate variability during concurrent demand conditions indicated increased mental stress. Although strength recovery was not influenced by mental workload, a slower heart rate recovery was observed after concurrent demand conditions. The findings from this study provide fundamental evidence that physical capacity (fatigability and recovery) is adversely affected by mental workload. Thus, it is critical to determine or evaluate occupational demands based on modified muscular capacity (due to mental workload) to reduce risk of WMSD development.

Influence of mental workload on muscle endurance, fatigue, and recovery during intermittent static work

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 continuous SWAT subscales while one used the discrete SWAT subscale. Fifteen subjects participated in the experiment. The scales were compared with the original SWAT scale in terms of sensitivity and pretask procedure completion time when performing arithmetic tasks. The results show that all four variants are more sensitive than the conventional SWAT scale and that the pairwise comparison procedure takes significantly less pretask completion time compared with the original SWAT scale. Thus, the conventional pretask procedure can be replaced by a simple unweighted averaging to yield a scale of high sensitivity.

Simplified subjective workload assessment technique.

As consumers are becoming increasingly selective of what they wear on their feet, manufacturers are experiencing problems developing and fitting the right footwear. Literature suggests that shoes with a shape similar to feet may be comfortable because they attempt to maintain the feet in a neutral posture. The objective of this paper is to develop a metric to quantify mismatches between feet and lasts and also to be able to generate the two-dimensional outline of the foot using the minimum number of landmarks. Fifty Hong Kong Chinese were participants in the experiment. In addition to subject weight, height, foot length and foot width, the left foot outlines were drawn and 18 landmarks were marked on each of the two-dimensional foot outlines. A step-wise procedure was used to reduce the chosen 18 landmarks to eight, such that the mean absolute negative error (an indicator of 'tightness') between the foot outline and the modelled curve was 1.3 mm. These eight landmarks seem to show an improvement over those proposed by other researchers, thus showing the importance of choosing the right landmarks for modelling the foot. The positive and negative absolute errors were on average 1.8 mm and 1.3 mm respectively. Moreover, the mean errors for the toe region and for the rest of the foot were 1.7 mm and 1.6 mm respectively. The results indicate that the foot outline, an important component for footwear functionality and fitting, may be modelled using eight critical landmarks.

Foot landmarking for footwear customization.

This study is an attempt to show how a "standard" foot can be parameterized using foot length, foot width, foot height, and a measure of foot curvature so that foot shape can be predicted using these simple anthropometric measures. The prediction model was generated using 40 Hong Kong Chinese men, and the model was validated using a different group of 25 Hong Kong Chinese men. The results show that each individual foot shape may be predicted to a mean accuracy of 2.1 mm for the left foot and 2.4 mm for the right foot. Application of this research includes the potential design and development of custom footwear without the necessity of expensive 3-D scanning of feet.

Foot Shape Modeling

Shoe-last design innovation for better shoe fitting

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 t...

Ameersing Luximon

Papers

Simplified subjective workload assessment technique.

Foot landmarking for footwear customization.

Foot Shape Modeling

Shoe-last design innovation for better shoe fitting

The Quality of Footwear Fit: What we know, don't know and should know