Gül E. Okudan

Triz and axiomatic design: a review of case-studies and a proposed synergistic use

With increasing competition in the market, expediting the problem solving process has become crucial in the industry. As such, a number of problem solving techniques have been devised to efficiently tackle problems of varying natures. Two such techniques, Theory of Inventive Problem Solving (TRIZ) and Axiomatic Design (AD), have been widely applied in a variety of industries and services, recently. This paper reviews practical applications of TRIZ and AD in solving industrial problems related to manufacturing and designing. In addition, compatibility issues of TRIZ and AD are discussed. Based on our review, we propose a new approach of applying these two techniques concurrently to solve a problem to attain efficiency and quality in the problem solving process. The approach has been demonstrated through a real life case-study of productivity enhancement in a manufacturing industry.

Concept selection methods - a literature review from 1980 to 2008

The evaluation process of conceptual design alternatives is a critical point for companies which operate in fast-growing markets due to its influence on all subsequent phases with regard to cost, quality and performance of the end-product. While various methods exist that are able to successfully carry out this difficult and time-consuming process, many have drawbacks (e.g., inability to consider coupled decision, inability to incorporate uncertainty, etc). The growing number of articles on concept selection literature is an indication of the importance of effective design strategy and of its role in improving the competitiveness of an organisation. Accordingly, this paper surveys concept selection methods (CSMs) published between 1980 and 2008. Our overall goal is to provide designers and decision-makers with an overview of the underlying principles used in the reviewed methods along with the advantages and limitations.

An investigation on the impact of product modularity level on supply chain performance metrics: an industrial case study

The benefit of integrating product design decisions and supply chain design decisions has been recognized by researchers. Such integration can facilitate better communication between design teams and operations groups. Consequently, potential supply chain risks can be highlighted and addressed before the launch of a new product. Modularization is one of the most critical elements for both product design and supply chain design decisions as it impacts the assembly sequence and hence the selection of component and module suppliers. However, the impact of modularity level on supply chain performance is still unclear, and thus is the focus of this study. The proposed analytical method incorporates both product design and supply chain design functions, and hence, enables simultaneous consideration of these decisions. The supply chain performances of all two-module and three-module design concepts are fully investigated in an effort to explore the impact of modularity level on supply chain performance. Results show that increased modularity is advantageous for the time-based performance of a supply chain network, whereas decreased modularity yields superiority in terms of cost performance.

Computer-aided generation of modularised conceptual designs with assembly and variety considerations

Design is the foremost step in the development of any electro-mechanical product. One limitation of existing design tools is that they only focus either on the initial design phase such as customer needs gathering, or on the later phases such as design embodiment or detailed design phase. As a result, there are very few existing computational tools to aid the designers at the conceptual design stage. The proposed research seeks to eliminate this drawback by providing a computerised conceptual design framework that incorporates Modularity, design for assembly (DFA) and design for variety (DFV) principles. Conceptual design alternatives obtained from the proposed research framework are ranked based on minimum assembly time, and are composed of modules in such a way that future changes in customer needs are satisfied only by replacing certain modules. This paper provides a detailed discussion of the proposed framework obtained by amalgamating Modularity, DFA, and DFV. Working of the framework is also demonstrated with the help of an electronic toothbrush design example.

Fuzzy AHP and utility theory based patient sorting in emergency departments

Triage, a classification system used to separate patients based on the acuity of their condition, is considered in this study. Triage process relies on the nurses interaction with the patient (e.g., a conversation on symptoms, visual observation, and vital sign measurements), and the subsequent severity classification. However, potential miscommunication, and thus uncertainty could be present in this process. In order to account for this uncertainty, a triage algorithm that uses fuzzy analytic hierarchy process (FAHP) along with the multi-attribute utility theory (MAUT) to sort the patients is presented. FAHP is used to get an acuity score on the chief complaint, and MAUT integrates this score with age, gender, and pain level to provide a final prioritisation. In the paper, a clinical case study is provided for which we used an expert nurses judgments to build the FAHP and the utility functions.

Utility function-based patient prioritisation in the emergency department

With the increased awareness of productivity problems in healthcare operations, many researchers have proposed the implementation of tools and methods developed in other fields to benefit healthcare delivery. Accordingly, we present in this paper an exploratory work using a hypothetical example of a decision-making methodology, the multi-attribute utility analysis, to healthcare. The hypothetical sample problem presented involves patient prioritisation in an Emergency Department (ED), where several patients require immediate attention and they all have the same acuity level. Utility theory is selected for this application to appropriately account for the uncertainty in the decision problem. [Submitted 01 March 2008; Revised 05 September 2008; Revised 02 February 2009; Accepted 07 February 2009]

Perceived feature utility-based product family design: a mobile phone case study

To assure profit maximization through mass customization and personalization, effectively eliciting consumer needs across different market segments is critical. Although functional performance specifications and adequacy of various design forms can be measured directly and objectively, many designers and engineers struggle with clearly evaluating product criteria requiring subjective consumer input; the fact that these inputs change over time further complicates the process. To appropriately evaluate product criteria, an effective design decision-making analysis is required. In this study, we propose a methodology to assure effective elicitation of needs and their inclusion in design decision making and illustrate it using a mobile phone product family design scenario. First, consumer perceived utility of design features is gathered using a questionnaire (500+ responses) and then modeled using multi- attribute utility theory to facilitate the evaluation of a product family while responding to needs across customer clusters shaped by demographics. The methodology goal is to determine the relative goodness of a product family in comparison to its competition. We also compare and evaluate the application of the proposed method to conjoint analysis.

Rank aggregation methods comparison: A case for triage prioritization

This paper seeks to test and to determine a suitable aggregation method to represent a set of rankings made by individual decision makers (DMs). A case study for triage prioritization is used to test the aggregation methods. The triage is a decision-making process with which patients are prioritized according to their medical condition and chance of survival on arrival at the emergency department (ED). There is a lot of subjective decision-making in the process which leads to discrepancies among nurses. Four rank aggregation methods are applied to the prioritization data and then an expert evaluates the results and judges them on practicality and acceptability. The proposed recommendation for preference aggregation is the method of the estimation of utility intervals. Expert opinion is highly valued in a decision-making environment such as this, where experience and intuition are key to successful job performance and outcomes.

A Multi-Stage Problem Formulation for Concept Selection for Improved Product Design

In this paper, a new concept selection method is proposed and its application is demonstrated. The utility theory based proposed method formulates the concept selection problem as a multi-stage decision. The proposed method has improvements in its ease of use, and accounting for potentially coupled decisions in comparison to other methods found in the literature. We first present a comprehensive review of the existing concept selection methods, and then explain the proposed approach. The paper concludes with its application on a case study along with recommendations for future work

A Study on Situated Cognition: Product Dissection's Effect on Redesign Activities.

Situated cognition theory describes the context of a learning activity’s effect on learner’s cognition. In this paper, we use situated cognition theory to examine the effect of product dissection on product redesign activities. Two specific research questions are addressed: 1) Does situated cogni tion, in the form of product dissection, improve product functionality during redesign exercise?, and 2) Does situated cognition, again in the form of product dissection, affect the creativity during product redesign? In this study, three sections of first-year students in two different locations – The Pennsylvania State University (Penn State) and Missouri University of Science and Technology (S&T) – performed product redesign using coffee makers. The redesigned products have been analyzed with respect to both depth (detail level) and creativity. Based on our results, we find that situated cognition, in the form of product dissection, improves product functionality during redesign and positively affects creativity. The implications of these results are also discussed.