Redesign and Evaluation of the Grocery Store Self-Checkout Systems from Universal Design Perspectives.

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Title: Redesign and Evaluation of the Grocery Store Self-Checkout Systems from Universal Design Perspectives.
Author: Bajaj, Komal
Advisors: Dr. Carolyn M Sommerich, Committee Member
Prof. Haig Khachatoorian, Committee Member
Dr. Gary Mirka, Committee Chair
Abstract: Each one of us is physically challenged at some point in life. Old age, extreme statures (short or long, thin or fat), or some accident might produce conditions wherein we are unable to continue our work like we normally do. So it is in the best interests of everyone to design a product that accommodates the needs of all of its users. Being ergonomists, our task is to assess the existing products and services, showing where and how they fail to 'fit' the user (in every sense of the word) and suggest ways to improve the fit in order to make the products and services safer, more comfortable and more productive for the whole range of people who use them — including children, the elderly and the disabled. — Universal design is the design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design?- Ron Mace (1994). In this sense, the two fields — Ergonomics and Design — merge. In the summer of 2002, while interning with the Center for Universal Design, Raleigh, NC, I had the opportunity to get involved in a focus group study of the recently emerged grocery store Self-Checkout Systems (SCO's). People with various kinds of disabilities — mobility, hearing, vision, perceptual and cognitive disabilities — were asked to perform the process of Self-Checkout (SCO) in actual grocery stores. Although no quantitative variables were analyzed in that study, it was observed that the SCO's were far from being usable by the disabled population. Thus, emerged the idea of applying my knowledge of ergonomics to the redesign of one of the most prevalent models of the SCO (the U-Scan Express) so that the redesigned system is more 'universally' acceptable than the existing system. Because of time and resource constraints, the redesign focused on the accessibility for wheelchair users and non-wheelchair users from the physical perspective considering ergonomic factors such as fit, reach, posture etc. Two prototypes — one of the conventional SCO and another of a redesigned version — were built in the Ergonomics Laboratory at North Carolina State University. Fifteen subjects— five wheelchair users and ten non-wheelchair users — were asked to simulate the process of self-checkout on the two different workstations. The workstations were evaluated on the basis of productivity, posture and users' subjective feedback. Results indicate that productivity was not significantly affected across workstations, for either of the two user groups. Posture was significantly improved across workstations for both the groups. Shoulder posture was significant ly improved for both the groups — a maximum shoulder angle reduction of 64% for wheelchair users and 69% for non-wheelchair users was recorded. Trunk posture was significantly improved for wheelchair users with a maximum trunk angle reduction of 66.5% while for the non-wheelchair users, the trunk flexion angle did not significantly increase. Subjective feedback from both the groups showed a preference for the new design in terms of ease, accuracy, quickness and overall preference although, the preference was higher for the wheelchair group than the nonwheelchair group. The average scores of both the user groups on 'willingness' in using the redesigned system in preference to the existing system were also above neutral ? all five of the wheelchair users and 8 out of 10 of the non-wheelchair users responded with a score above neutral for willingness. Thus, it was concluded that the redesigned SCO would be more 'universally' acceptable than the conventional/existing SCO.
Date: 2003-09-19
Degree: MS
Discipline: Industrial Engineering

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