Experimental Studies Assessing the Repeatability of a Functional Modeling Derivation Method

2003 ◽  
Vol 125 (4) ◽  
pp. 682-693 ◽  
Author(s):  
Mark A. Kurfman ◽  
Michael E. Stock ◽  
Robert B. Stone ◽  
Jagan Rajan ◽  
Kristin L. Wood

This paper presents the results of research attempts to substantiate repeatability and uniqueness claims of a functional model derivation method following a hypothesis generation and testing procedure outlined in design research literature. Three experiments are constructed and carried out with a participant pool that possesses a range of engineering design skill levels. The experiments test the utility of a functional model derivation method to produce repeatable functional models for a given product among different designers. In addition to this, uniqueness of the functional models produced by the participants is examined. Results indicate the method enhances repeatability and leads designers toward a unique functional model of a product. Shortcomings of the method and opportunities for improvement are also identified.

Author(s):  
Mark A. Kurfman ◽  
Robert B. Stone ◽  
Jagan R. Rajan ◽  
Kristin L. Wood

Abstract As more design methodologies are researched and developed, the question arises as to whether these new methodologies are actually advancing the field of engineering design or instead cluttering the field with more theories. There is a critical need to test new methodologies for their contribution to the field of design engineering. This paper presents the results of research attempts to substantiate repeatability claims of the functional model derivation method. Three experiments are constructed and carried out with a participant pool that possesses a range of engineering design skill levels. The experiments test the utility of the functional model derivation method to produce repeatable functional models for a given product among different designers. Results indicate the method is largely successful and identify its key strengths as well as opportunities for improvement.


Author(s):  
Mark A. Kurfman ◽  
Robert B. Stone ◽  
Mike Van Wie ◽  
Kristin L. Wood ◽  
Kevin N. Otto

Abstract A model of how a product should function to satisfy customers is an essential element in clarifying, identifying, and establishing product architectures. Such functional models greatly enhance the generation of creative form solutions to a chosen architecture. A wider breadth of solutions is generally possible, implementing new and stable technologies. In turn, using the recent concepts of design repositories, the possibilities exist to archive, retrieve, compute, reconfigure, and reason with the product forms. To realize these benefits to the fullest extent possible, functional modeling needs further theoretical development. A formalism of function classes, vocabulary, topologies, and methodology is a first step towards this goal. Recent research efforts have focused on each of these elements, where great strides toward repeatable formalisms have been made. Yet, across the engineering design field, very little active experimentation has been pursued to test the veracity of these elements, individually and as a whole. We address this issue here through a preliminary set of experiments conducted at three separate universities. Design teams and individuals are asked to create functional models, in the context of product development, with and without the formalisms. The outcomes of the modeling effort are analyzed to determine the repeatability of the process. Early results are quite encouraging. Very repeatable results are obtained for three product evolutions, including a toaster, a power screwdriver, and a toy dart gun. In addition, weaknesses in current formalisms are uncovered, pointing to new directions for advancing the field and for carrying out more advanced experimentation.


Author(s):  
Alexander R. Murphy ◽  
Jacob T. Nelson ◽  
Matt R. Bohm ◽  
Robert L. Nagel ◽  
Julie S. Linsey

Functional modeling is a tool used for system abstraction. By divorcing system function from component structure, functional modeling allows designers to more easily identify design opportunities and compartmentalize product functions, which can lead to innovation during the ideation process. In this paper, we examine the reliability of a rubric used to evaluate student-generated functional models by comparing interrater reliabilities on a question-by-question basis from a previous study where an examination of the reliability of each question was not assessed. We then suggest changes to the rubric in order to improve the rubric’s overall interrater reliability as well as its question-by-question interrater reliability. These rubric alterations include clarification of vague language, inclusion of examples and counter examples, and a procedure for handling nonexistent functional components as opposed to incorrect or “nonsensical” functional components. This work is in contribution to the ongoing development of this functional modeling rubric as an education instrument. As functional modeling becomes more widely accepted in the design community and in engineering curricula, it is important to have a validated evaluation metric with which to assess student-generated functional models.


Author(s):  
Robert L. Nagel ◽  
Robert B. Stone ◽  
Daniel A. McAdams

Conceptual design is a vital stage in the development of any product, and its importance only increases with the complexity of a design. Functional modeling with the Functional Basis provides a framework for the conceptual design of electromechanical products. This framework is just as applicable to the conceptual design of automated solutions where an engineered product with components spanning multiple engineering domains is designed to replace or aid a human and his or her tools in a human-centric process. This paper presents research toward the simplification of the generation of conceptual functional models for automation solutions. The presented methodology involves the creation of functional and process models to fully explore existing human operated tasks for potential automation. Generated functional and process models are strategically combined to create a new conceptual functional model for an automation solution to potentially automate the human-centric task. The presented methodology is applied to the generation of a functional model for a conceptual automation solution. Then conceptual automation solutions generated through the presented methodology are compared to existing automation solutions to demonstrate the effectiveness of the presented methodology.


2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Robert L. Nagel ◽  
Matt R. Bohm ◽  
Julie S. Linsey ◽  
Marie K. Riggs

An engineering design curriculum that introduces functional modeling methods is believed to enhance the ability to abstract complex systems, assist during the concept generation phase of design, and reduce design fixation. To that end, a variety of techniques for considering function during design have been proposed in the literature, yet there are a lack of validated approaches for teaching students to generate functional models and no reliable method for the assessment of functional models. This paper presents a study investigating students' ability to generate functional models during a homework assignment; the study includes three different treatment conditions: (1) students who receive only a lecture on functional modeling, (2) students who receive a lecture on functional modeling as well as a step-by-step example, and (3) students who receive a lecture, a step-by-step example, and an algorithmic approach with grammar rules. The experiment was conducted in a cornerstone, undergraduate engineering design course, and consequently, was the students' first exposure to functional modeling. To assess student generated functional models across all three conditions, an 18 question functional model scoring rubric was developed based on flow-based functional modeling standards. Use of the rubric to assess the student generated functional models resulted in high inter-rater agreement for total score. Results show that students receiving the step-by-step example perform as well as students receiving the step-by-step example and an algorithmic approach with grammar rules; both groups perform better than the lecture-only group.


Author(s):  
Inna Doronina ◽  
Svetlana Londar

The conclusions on using functional modeling results for library processes modernization are presented. The authors prove that such functional models make the basis for efficient information services. The study was accomplished at Valuy district Intersettlement Library, Belgorod Oblast, Russia.


Author(s):  
Alex Mikes ◽  
Katherine Edmonds ◽  
Robert B. Stone ◽  
Bryony DuPont

Abstract The purpose of this research is to find the optimum values for threshold variables used in a data mining and prediction algorithm. We also minimize and stratify a training set to find the optimum size based on how well it represents the whole dataset. Our specific focus is automating functional models, but the method can be applied to any dataset with a similar structure. We iterate through different values for two of the threshold variables in this process and cross-validate to calculate the average accuracy and find the optimum values for each variable. We optimize the training set by reducing the size by 78% and stratifying the data, whereby we achieve an accuracy that is 96% as good as the whole training set and takes 50% less time. These optimum values can be used to better predict the functions and flows of any future product based on its constituent components, which can be used to generate a complete functional model.


Author(s):  
Katherine Edmonds ◽  
Alex Mikes ◽  
Bryony DuPont ◽  
Robert B. Stone

Abstract Expanding on previous work of automating functional modeling, we have developed a more informed automation approach by assigning a weighted confidence metric to the wide variety of data in a design repository. Our work focuses on automating what we call linear functional chains, which are a component-based section of a full functional model. We mine the Design Repository to find correlations between component and function and flow. The automation algorithm we developed organizes these connections by component-function-flow frequency (CFF frequency), thus allowing the creation of linear functional chains. In previous work, we found that CFF frequency is the best metric in formulating the linear functional chain for an individual component; however, we found that this metric did not account for prevalence and consistency in the Design Repository data. To better understand our data, we developed a new metric, which we refer to as weighted confidence, to provide insight on the fidelity of the data, calculated by taking the harmonic mean of two metrics we extracted from our data, prevalence, and consistency. This method could be applied to any dataset with a wide range of individual occurrences. The contribution of this research is not to replace CFF frequency as a method of finding the most likely component-function-flow correlations but to improve the reliability of the automation results by providing additional information from the weighted confidence metric. Improving these automation results, allows us to further our ultimate objective of this research, which is to enable designers to automatically generate functional models for a product given constituent components.


2016 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Maral Babapour Chafi

Designers engage in various activities, dealing with different materials and media to externalise and represent their form ideas. This paper presents a review of design research literature regarding externalisation activities in design process: sketching, building physical models and digital modelling. The aim has been to review research on the roles of media and representations in design processes, and highlight knowledge gaps and questions for future research.


Author(s):  
N. Kuji ◽  
T. Takeda ◽  
S. Nakamura ◽  
Y. Komine

Abstract A new logic-model derivation method for leak faults observed by light-emission microscopy (LEM) or in liquid-crystal analysis (LCA) has been developed to verify those faults by comparing them with failures observed on an LSI tester. Since CMOS devices display various kinds of faulty behavior depending on leak resistance, it is essential to include the effects of this resistance in logic models. Considering that the resistance of leaks observed in LEM and LCA ranges from 10 to 10,000 ohm, the new logic models have been derived so that the leak fault could be easily incorporated into logic simulators without SPICE simulation. The feasibility of the proposed method has been demonstrated by using it to diagnose LEM and LCA faults causing logic failure in a 20k-gate logic LSI circuit.


Sign in / Sign up

Export Citation Format

Share Document