A Participative Approach for Objective and Subjective Evaluation of Seat Discomfort and User Interface Usability
Creators: name: Del Giudice, Domenico Maria
Publisher: name: Università degli Studi di Napoli Federico II
Year: 2015

description: The main aim of the work is the objective and subjective evaluation of two aspects of the interaction user-product, the seating discomfort and the user interface usability, relevant to industrial design, by using innovative methodologies for generating interpretative and predictive models that allowed the development of analysis strategies useful to improve the satisfaction of use of the types of industrial products considered.
On the first aspect investigated, research in the field of medicine and epidemiology has shown that, over the past decades, the incidence of work-related musculoskeletal disorders (WMSDs) has considerably increased due to sedentary modern lifestyle, closely related to prolonged period of sitting. The importance of good office seating design in improving human wellness, greatly motivates the interest of specialized literature in topics related to the investigation of the biomechanical aspects of sitting and their effect on perceived discomfort. Typically discomfort assessment is realized on the basis of subjective evaluations and/or postural analysis by the interface pressures. In such context, the experimental sessions and the related data analysis were aimed to investigating on three critical aspects of seat discomfort assessment: 1) the relationship between subjective and objective measures of seat discomfort; 2) gender-based differences in seat interface pressure distribution; 3) discriminant effectiveness of indexes based on seat interface pressure.
On the second aspect investigated, it's helpful to recognize that, today, design team can speed up the process of managing information related to design process by adopting digital pattern tools. These tools, as Knowledge Based Engineering (KBE) systems, can assist engineers in capture and re-use the multidisciplinary knowledge in an integrated way, in order to reduce time and cost of designing, to automate repetitive tasks and to support activities in conceptual design. The KBE analyzed in this study is a new digital pattern tool that supports the designers of automotive gearboxes. In such context, the research has focused on the evaluation of interface usability that represents a critical point in the development of a KBE system to demonstrate an effective reduction in the time and cost of designing and increased satisfaction in its use.
The methods used for the two aspects studied are both theoretical and experimental and can be summarized in four main steps:
1) developmentofparticipativeprotocolsandexecutionofexperimentalsessionswith collecting of objective measures related to the interaction user-product and subjective measures related to user perceptions;
2) organization, classification and synthesis of experimental data collected by using techniques of descriptive statistics;
3) definition of interpretative and predictive models of phenomena investigated including by developing synthetic indexes, by using techniques of multivariate and multicriteria analysis;
4) statisticalvalidationofthesemodelsandindexes.
The main results achieved concern the assessment of user-product interaction for
different types of industrial products where such evaluation is essential. The outcomes are originals because they allowed to find the factors that had most influence on case studies and to develop synthetic indexes useful for identify some critical issues related use. Statistical data analysis provided new information relating to phenomena examined. Furthermore, the proposed data analysis strategies can be easily adapted to other experimental contexts, involving different target populations, and could have important effects in the industrial field, because they allow the reduction of design time (with obvious consequences on cost) and improvement of products in terms of end-user satisfaction.