An upgradable product-service system design method based on kaos and time-axis

Abstract

For recent decades, product-service system (PSS), an integration of products and services, has become a promising business mode for traditional manufacturing firms to upgrade their business instead of only selling products. However, after the 2000s, more and more attention has been paid to the upgradability of this system. It is worried that the enlarged life cycle of services could not enlarge the life of the business. Although most services and products are designed to satisfy customers for a longer time, some customers are reluctant to keep using PSS until the end of their physical life due to the changing social and technical factors. With this consideration, the concept of upgradable PSS (UPSS), a type of PSS that could predict future change and plan upgrades in advance is proposed to maintain the satisfaction of stakeholders. To date, it is found that the current UPSS is still in a conceptual stage, which lacks detailed and normative methods to ensure the identification and refinement process of requirements towards upgradable PSS are effective because of the knowledge and subjective limitations. This paper introduces an upgradable Product-Service System (PSS) design method based on time-axis design and Knowledge Acquisition in automated Specification (KAOS). This method could enable designers to anticipate future changes in stakeholders’ value propositions and refine future requirements into rational upgradable solutions for PSS. The proposed method begins by introducing the concept of time-axis-based design, providing designers with support in identifying future changes across different temporal dimensions. Based on the grasped change in future, the modified KAOS is proposed to support designers in identifying the PSS characteristics to realize stakeholders’ expectations and understandably show the structure of PSS. To verify the effectiveness, the authors have adopted a case study of primary school furniture system design. For future research, a developed solution-generation technique is expected.