Imprecision in Engineering Design

1995 ◽  
Vol 117 (B) ◽  
pp. 25-32 ◽  
Author(s):  
E. K. Antonsson ◽  
K. N. Otto

Methods for incorporating imprecision in engineering design decision-making are briefly reviewed and compared. A tutorial is presented on the Method of Imprecision (MoI), a formal method, based on the mathematics of fuzzy sets, for representing and manipulating imprecision in engineering design. The results of a design cost estimation example, utilizing a new informal cost specification, are presented. The MoI can provide formal information upon which to base decisions during preliminary engineering design and can facilitate set-based concurrent design.

1995 ◽  
Vol 117 (B) ◽  
pp. 25-32 ◽  
Author(s):  
E. K. Antonsson ◽  
K. N. Otto

Methods for incorporating imprecision in engineering design decision-making are briefly reviewed and compared. A tutorial is presented on the Method of Imprecision (MoI), a formal method, based on the mathematics of fuzzy sets, for representing and manipulating imprecision in engineering design. The results of a design cost estimation example, utilizing a new informal cost specification, are presented. The MoI can provide formal information upon which to base decisions during preliminary engineering design and can facilitate set-based concurrent design.


1999 ◽  
Vol 11 (4) ◽  
pp. 218-228 ◽  
Author(s):  
Michael J. Scott ◽  
Erik K. Antonsson

Author(s):  
David Wolf ◽  
Timothy W. Simpson ◽  
Xiaolong Luke Zhang

Thanks to recent advances in computing power and speed, designers can now generate a wealth of data on demand to support engineering design decision-making. Unfortunately, while the ability to generate and store new data continues to grow, methods and tools to support multi-dimensional data exploration have evolved at a much slower pace. Moreover, current methods and tools are often ill-equipped at accommodating evolving knowledge sources and expert-driven exploration that is being enabled by computational thinking. In this paper, we discuss ongoing research that seeks to transform decades-old decision-making paradigms rooted in operations research by considering how to effectively convert data into knowledge that enhances decision-making and leads to better designs. Specifically, we address decision-making within the area of trade space exploration by conducting human-computer interaction studies using multi-dimensional data visualization software that we have been developing. We first discuss a Pilot Study that was conducted to gain insight into expected differences between novice and expert decision-makers using a small test group. We then present the results of two Preliminary Experiments designed to gain insight into procedural differences in how novices and experts use multi-dimensional data visualization and exploration tools and to measure their ability to use these tools effectively when solving an engineering design problem. This work supports our goal of developing training protocols that support efficient and effective trade space exploration.


Author(s):  
Jeremy J. Michalek ◽  
Oben Ceryan ◽  
Panos Y. Papalambros ◽  
Yoram Koren

An important aspect of product development is design for manufacturability (DFM) analysis that aims to incorporate manufacturing requirements into early product decision-making. Existing methods in DFM seldom quantify explicitly the tradeoffs between revenues and costs generated by making design choices that may be desirable in the market but costly to manufacture. This paper builds upon previous work coordinating models for engineering design and marketing product line decision-making by incorporating quantitative models of manufacturing investment and production allocation. The result is a methodology that considers engineering design decisions quantitatively in the context of manufacturing and market consequences in order to resolve tradeoffs, not only among performance objectives, but also between market preferences and manufacturing cost.


Author(s):  
Raymond E. Levitt ◽  
Yan Jin ◽  
Clive L. Dym

Artificial intelligence (AI) applications to design have tended to focus on modeling and automating aspects of single discipline design tasks. Relatively little attention has thus far been devoted to representing the kinds of design ‘metaknowledge’ needed to manage the important interface issues that arise in concurrent design, that is, multidisciplinary design decision-making. This paper provides a view of the process and management of concurrent design and evaluates the potential of two AI approaches—blackboard architectures and co-operative distributed problem-solving (CDPS)—to model and support the concurrent design of complex artifacts. A discussion of the process of multidisciplinary design highlights elements of both sequential and concurrent design decision-making. We identify several kinds of design metaknowledge used by expert managers to: partition the design task for efficient execution by specialists; set appropriate levels of design conservatism for key subsystem specifications; evaluate, limit and selectively communicate design changes across discipline boundaries; and control the sequence and timing of the key (highly constrained and constraining) design decisions for a given type of artifact. We explore the extent to which blackboard and CDPS architectures can provide valid models of and potential decision support for concurrent design by (1) representing design management metaknowledge, and (2) using it to enhance both horizontal (interdisciplinary) and vertical (project life cycle) integration among product design, manufacturing and operations specialists.


Author(s):  
Youyi Bi ◽  
Murtuza Shergadwala ◽  
Tahira Reid ◽  
Jitesh H. Panchal

Research on decision making in engineering design has focused primarily on how to make decisions using normative models given certain information. However, there exists a research gap on how diverse information stimuli are combined by designers in decision making. In this paper, we address the following question: how do designers weigh different information stimuli to make decisions in engineering design contexts? The answer to this question can provide insights on diverse cognitive models for decision making used by different individuals. We investigate the information gathering behavior of individuals using eye gaze data from a simulated engineering design task. The task involves optimizing an unknown function using an interface which provides two types of information stimuli, including a graph and a list area. These correspond to the graphical stimulus and numerical stimulus, respectively. The study was carried out using a set of student subjects. The results suggest that individuals weigh different forms of information stimuli differently. It is observed that graphical information stimulus assists the participants in optimizing the function with a higher accuracy. This study contributes to our understanding of how diverse information stimuli are utilized by design engineers to make decisions. The improved understanding of cognitive decision making models would also aid in improved design of decision support tools.


Author(s):  
Kuang-Hua Chang ◽  
Javier Silva ◽  
Ira Bryant

Abstract Conventional product development process employs a design-build-break philosophy. The sequentially executed product development process often results in a prolonged lead-time and an elevated product cost. The proposed concurrent design and manufacturing (CDM) process employs physics-based computational methods together with computer graphics technique for product design. This proposed approach employs Virtual Prototyping (VP) technology to support a cross-functional team analyzing product performance, reliability, and manufacturing cost early in the product development stage; and conducting quantitative trade-off for design decision making. Physical prototypes of the product design are then produced using Rapid Prototyping (RP) technique primarily for design verification purposes. The proposed CDM approach holds potential for shortening the overall product development cycle, improving product quality, and reducing product cost. A software tool environment that supports CDM for mechanical systems is being built at the Concurrent Design and Manufacturing Research Laboratory (http://cdm.ou.edu) at the University of Oklahoma. A snap shot of the environment is illustrated using a two-stroke engine example. This paper presents three unique concepts and methods for product development: (i) bringing product performance, quality, and manufacturing cost together in early design stage for design considerations, (ii) supporting design decision-making through a quantitative approach, and (iii) incorporating rapid prototyping for design verification through physical prototypes.


2018 ◽  
Vol 58 (2) ◽  
pp. 679
Author(s):  
Janine M. Barrow

As the engineering design process for a major development project advances from concept through to ready for start up, many key decisions are made and controls formulated that ultimately influence environmental, social (and safety) outcomes. These decisions are often made based on sound technical grounds with key decision logs, hazard identification or hazard and operability studies or similar used to record the process, but with limited recognition of environmental outcomes. Many of the onshore and offshore regulations in Australia (most notably, the Offshore Petroleum and Greenhouse Gas (Environment) Regulations 2009) require environmental risks and impacts to be reduced to a level that is as low as reasonably practicable (ALARP). Additionally, justifiable assessment of controls and decisions are presented in the environment plans (EP) that are typically prepared later on in the design process. Challenges can often arise when geographically disparate design contractors lack ALARP assessment processes to evaluate decisions and controls from an environmental perspective and record outcomes for future use in regulatory documentation. This can be particularly pronounced for operations EPs. Janine shares her practical experience in environmental integration in engineering design to showcase methods that tangibly demonstrate robust decision-making, inclusive of delivering environmental outcomes, to regulators.


Author(s):  
Dipanjan D. Ghosh ◽  
Andrew Olewnik

Modeling uncertainty through probabilistic representation in engineering design is common and important to decision making that considers risk. However, representations of uncertainty often ignore elements of “imprecision” that may limit the robustness of decisions. Further, current approaches that incorporate imprecision suffer from computational expense and relatively high solution error. This work presents the Computationally Efficient Imprecise Uncertainty Propagation (CEIUP) method which draws on existing approaches for propagation of imprecision and integrates sparse grid numerical integration to provide computational efficiency and low solution error for uncertainty propagation. The first part of the paper details the methodology and demonstrates improvements in both computational efficiency and solution accuracy as compared to the Optimized Parameter Sampling (OPS) approach for a set of numerical case studies. The second half of the paper is focused on estimation of non-dominated design parameter spaces using decision policies of Interval Dominance and Maximality Criterion in the context of set-based sequential design-decision making. A gear box design problem is presented and compared with OPS, demonstrating that CEIUP provides improved estimates of the non-dominated parameter range for satisfactory performance with faster solution times. Parameter estimates obtained for different risk attitudes are presented and analyzed from the perspective of Choice Theory leading to questions for future research. The paper concludes with an overview of design problem scenarios in which CEIUP is the preferred method and offers opportunities for extending the method.


Author(s):  
Hiroyuki Sawada ◽  
Xiu-Tian Yan

Abstract Engineering design is an intensive decision making process. A designer with an informative and insightful decision making support can usually produce high quality product design solutions with less or no rework. However, with current support designers very often face challenge or even difficulties as more and more design parameters come into design decision making process when a design progresses. This paper proposes a novel approach to providing designers with such a decision support by using under-constraint design problem solver. It is argued that design requirements represented in the form of Product Design Specifications (PDSs) can be converted into a set of related constraint expressions. These PDS constraint sets, which are usually incomplete, i.e., under-constrained, can then be solved by the solver to provide a designer with guided solutions for each design parameter, thus support a designer to make an informative and insightful design decision. A case study is finally presented in the paper to demonstrate how this approach is used to solve a real engineering design problem — a robotic finger system design.


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