@article{brahma_ferguson_eckert_isaksson_2023, title={Margins in design - review of related concepts and methods}, ISSN={["1466-1837"]}, DOI={10.1080/09544828.2023.2225842}, abstractNote={Margins are defined as the difference between a design parameter’s minimum required value to ensure functionality, and its actual capability. Margins allow engineers to mitigate uncertainties of various kinds. While some margins are intentionally allocated, some others may get included inadvertently in designs or arise from changes to requirements. Although common in use, the concept of margins has not been formalised systematically. This paper offers the first systematic literature review of margins. Concepts related to margins can be found in various interrelated domains with similar underlying principles. However, these concepts have developed in isolation, leading to a divergent and fragmented understanding. This paper brings these strands together by differentiating between margins which may be deliberately added or discovered during a typical product lifecycle and relates this to various domains such as safety, manufacturing etc. The paper discusses approaches to model, size and allocate margins. The thematic analysis presents insights into the importance of systematic use and management of margins and also raises currently observable gaps in the literature.}, journal={JOURNAL OF ENGINEERING DESIGN}, author={Brahma, Arindam and Ferguson, Scott and Eckert, Claudia and Isaksson, Ola}, year={2023}, month={Jun} }
 @article{long_ferguson_2021, title={Assessing Lifecycle Value Using Object-Based Modeling by Incorporating Excess and Changeability}, volume={143}, ISSN={["1528-9001"]}, DOI={10.1115/1.4048218}, abstractNote={Abstract}, number={5}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Long, Daniel and Ferguson, Scott}, year={2021}, month={May} }
 @article{elliott_ferguson_buckner_2021, title={The Cost-Sorted Distance Method for Identifying Minima Within Firefly Optimization Results: Application to Engineering Design}, volume={21}, ISSN={["1944-7078"]}, DOI={10.1115/1.4047554}, abstractNote={Abstract}, number={1}, journal={JOURNAL OF COMPUTING AND INFORMATION SCIENCE IN ENGINEERING}, author={Elliott, Christopher M. and Ferguson, Scott M. and Buckner, Gregory D.}, year={2021}, month={Feb} }
 @article{long_morkos_ferguson_2021, title={Toward Quantifiable Evidence of Excess' Value Using Personal Gaming Desktops}, volume={143}, ISSN={["1528-9001"]}, DOI={10.1115/1.4049520}, abstractNote={Abstract}, number={3}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Long, Daniel and Morkos, Beshoy and Ferguson, Scott}, year={2021}, month={Mar} }
 @misc{donndelinger_ferguson_2020, title={Design for the Marketing Mix: The Past, Present, and Future of Market-Driven Engineering Design}, volume={142}, ISSN={["1528-9001"]}, DOI={10.1115/1.4045041}, abstractNote={Abstract}, number={6}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Donndelinger, Joseph A. and Ferguson, Scott M.}, year={2020}, month={Jun} }
 @article{long_ferguson_2020, title={Studying Dynamic Change Probabilities and Their Role in Change Propagation}, volume={142}, ISSN={["1528-9001"]}, DOI={10.1115/1.4046674}, abstractNote={Abstract}, number={10}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Long, Daniel and Ferguson, Scott}, year={2020}, month={Oct} }
 @article{long_rehm_ferguson_2018, title={Benefits and challenges of using unmanned aerial systems in the monitoring of electrical distribution systems}, volume={31}, ISSN={1040-6190}, url={http://dx.doi.org/10.1016/J.TEJ.2018.02.004}, DOI={10.1016/J.TEJ.2018.02.004}, abstractNote={This paper presents a study coming from an academic and industry partnership with the goals of exploring potential uses for UAS in distribution system operation and maintenance, establishing baseline costs and capabilities via equipment field tests, and simulating the cost benefits of increased maintenance. Existing UAS technology is shown to be capable of providing situational awareness for disaster response as well as increasing the number of maintenance inspections and speeding them up.}, number={2}, journal={The Electricity Journal}, publisher={Elsevier BV}, author={Long, Daniel and Rehm, P.J. and Ferguson, Scott}, year={2018}, month={Mar}, pages={26–32} }
 @inproceedings{long_ferguson_2017, title={A case study of evolvability and excess on the B-52 stratofortress and FA-18 hornet}, DOI={10.1115/detc2017-68287}, abstractNote={The moment a system is put into service it begins to lose value as technological and societal changes accrue while the system is frozen in the state it was constructed. System decision makers are faced with the choice of accepting a decline in performance, updating the design, or retiring the system. Each time a decision maker faces these alternatives, the value of the available options must be evaluated to determine the preferred course of action. A design that can adapt to changes with minimal cost should provide more value over a longer period than a system that is initially less costly, but less adaptable. This is especially desirable for systems that have large initial costs and/or a lengthy development cycle. The purpose of this paper is to evaluate the United States Air Force (USAF) B-52 Stratofortress and the United States Navy (USN) F/A-18 Hornet to characterize the changes in desired capabilities and what system attributes allowed them to either successfully adapt or prevented them from adapting. These observations allow the development of heuristics that designers can use during system design to enhance system lifetime value.}, booktitle={Proceedings of the asme international design engineering technical conferences and computers and information in engineering conference, 2017, vol 4}, author={Long, D. and Ferguson, S.}, year={2017} }
 @article{allen_mattson_thacker_ferguson_2017, title={Design for excess capability to handle uncertain product requirements in a developing world setting}, volume={28}, ISSN={["1435-6066"]}, DOI={10.1007/s00163-017-0253-8}, number={4}, journal={RESEARCH IN ENGINEERING DESIGN}, author={Allen, Jeffrey D. and Mattson, Christopher A. and Thacker, Kendall S. and Ferguson, Scott M.}, year={2017}, month={Oct}, pages={511–527} }
 @inproceedings{white_ferguson_2017, title={Exploring architecture selection and system evolvability}, DOI={10.1115/detc2017-68290}, abstractNote={For engineered systems, one of the first decisions a designer must make is the architecture that will solve the established high level function. In most cases, this can be accomplished in a multitude of ways, with each original architecture having strengths and weaknesses. This paper explores how the architecture choice for a system impacts the ability to evolve and meet future needs. The lessons learned from this paper are extracted from a case study where three systems that perform the same task via different architectural solutions are considered. These systems are them compared to understand how well they adhere to, or violate, the Empirically-Derived Principles for Designing Products with Flexibility for Future Evolution introduced by Tilstra et al.}, booktitle={Proceedings of the asme international design engineering technical conferences and computers and information in engineering conference, 2017, vol 2b}, author={White, S. and Ferguson, S.}, year={2017} }
 @article{joglekar_von hagel_pankow_ferguson_2017, title={Exploring how optimal composite design is influenced by model fidelity and multiple objectives}, volume={160}, ISSN={["1879-1085"]}, DOI={10.1016/j.compstruct.2016.10.089}, abstractNote={This paper explores how optimal configuration of a composite panel is influenced by the choice of analysis model – analytic or computational – and the consideration of multiple objectives. While past research has explored aspects of this problem separately – composite ply orientation, multiple load scenarios, and multiple performance objectives – there has been limited work addressing the interactions between these factors. Three loading scenarios are considered in this work, and it is demonstrated that for certain scenarios an analytical model likely over-predicts composite performance. Further, for complex loading scenarios it is impossible to develop an analytical model. However, this work also demonstrates that the use of analytical models can be advantageous. Analytical models can provide similar estimates to computational models for some loading cases at significantly reduced computational expense. More importantly, it is also shown how solutions from the analytical model, which can be relatively cheap to find computationally, can be used to seed the initial designs of a Finite Element-based optimization. Run time reductions as large as 80% are demonstrated when these informed seeded designs are used, even when the designs were created for a different set of loading scenarios.}, journal={COMPOSITE STRUCTURES}, author={Joglekar, Shreyas and Von Hagel, Kayla and Pankow, Mark and Ferguson, Scott}, year={2017}, month={Jan}, pages={964–975} }
 @article{edwin_mazzoleni_gemmer_ferguson_2017, title={Modeling, construction and experimental validation of actuated rolling dynamics of the cylindrical Transforming Roving-Rolling Explorer (TRREx)}, volume={132}, ISSN={0094-5765}, url={http://dx.doi.org/10.1016/J.ACTAASTRO.2016.11.006}, DOI={10.1016/J.ACTAASTRO.2016.11.006}, abstractNote={Planetary surface exploration technology over the past few years has seen significant advancements on multiple fronts. Robotic exploration platforms are becoming more sophisticated and capable of embarking on more challenging missions. More unconventional designs, particularly transforming architectures that have multiple modes of locomotion, are being studied. This work explores the capabilities of one such novel transforming rover called the Transforming Roving-Rolling Explorer (TRREx). Biologically inspired by the armadillo and the golden-wheel spider, the TRREx has two modes of locomotion: it can traverse on six wheels like a conventional rover on benign terrain, but can transform into a sphere when necessary to negotiate steep rugged slopes. The ability to self-propel in the spherical configuration, even in the absence of a negative gradient, increases the TRREx's versatility and its concept value. This paper describes construction and testing of a prototype cylindrical TRREx that demonstrates that “actuated rolling” can be achieved, and also presents a dynamic model of this prototype version of the TRREx that can be used to investigate the feasibility and value of such self-propelled locomotion. Finally, we present results that validate our dynamic model by comparing results from computer simulations made using the dynamic model to experimental results acquired from test runs using the prototype.}, journal={Acta Astronautica}, publisher={Elsevier BV}, author={Edwin, L. and Mazzoleni, A. and Gemmer, T. and Ferguson, S.}, year={2017}, month={Mar}, pages={43–53} }
 @inproceedings{fang_bolotnov_2016, title={Bubble tracking simulations of turbulent two-phase flows}, DOI={10.1115/fedsm2016-1005}, abstractNote={Bubbly flow is quite common in various natural and engineering phenomena. In particular, nuclear engineers are interested in fundamental understanding of the bubbly flow behavior due to its importance in cooling light water reactor cores. Given the extreme conditions and complex support structures in nuclear reactor cores, it is very challenging to study the flow behavior using high-fidelity experiments. Typically validated computational codes are chosen as practical tools for the thermal-hydraulic and safety analyses. As the new generations of nuclear reactors are being developed, more advanced modeling techniques are required to design safe and efficient systems.}, booktitle={Proceedings of the asme fluids engineering division summer meeting, 2016, vol 1b}, author={Fang, J. and Bolotnov, I. A.}, year={2016} }
 @inproceedings{malinga_ferguson_buckner_2016, title={Design optimization and analysis of a prescribed vibration system}, DOI={10.1115/detc2016-60096}, abstractNote={Advances in technology that come with increased system complexity have accentuated the intricacy of decision making in engineering design. This has stimulated a great deal of research in ways to incorporate decision analysis and multi-attribute decision-making theory in engineering problems. In this research, Conjoint Value Analysis is incorporated into a scheme that optimizes the design of a multi-attribute Prescribed Vibration System. The influence of designer preferences is investigated by comparing design alternatives that result from different preference rankings. Monte Carlo-based uncertainty and sensitivity studies are performed to support the design process by providing additional information on the candidate designs. By understanding how small changes in the values of optimized parameters influence the system attributes, sensitivity analysis and uncertainty analyses can be used as a design robustness measure. The overall choice of the design is therefore based not only on the performance objectives but also on the resulting system robustness, which is very valuable considering manufacturing variations and tolerance stacks.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2016, Vol 2b}, author={Malinga, B. and Ferguson, S. M. and Buckner, G. D.}, year={2016}, pages={353–360} }
 @article{allen_mattson_ferguson_2016, title={Evaluation of System Evolvability Based on Usable Excess}, volume={138}, ISSN={["1050-0472"]}, DOI={10.1115/1.4033989}, abstractNote={Complex, large-scale engineered systems are an integral part of modern society. The cost of these systems is often high, while their ability to react to emergent requirements can be low. This paper proposes evolvability, based on usable excess, as a possible metric to promote system longevity. An equation for the usability of excess, previously defined only in terms of quantity, is improved to include the attributes of type, location, and form as well as quantity. A methodology for evaluating a system's evolvability is also presented. Using an automated assembly line as an example, we show that system evolvability can be modeled as a function of usable excess.}, number={9}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Allen, Jeffrey D. and Mattson, Christopher A. and Ferguson, Scott M.}, year={2016}, month={Sep} }
 @article{cansler_white_ferguson_mattson_2016, title={Excess Identification and Mapping in Engineered Systems}, volume={138}, ISSN={["1050-0472"]}, DOI={10.1115/1.4033884}, abstractNote={A system must continue to meet stakeholder needs throughout its service life to maintain value. Excess that is embedded into components during the design phase can enable in-service system evolution when new or changed requirements are introduced. However, while the concept of excess has been established in the literature, it is not clear how to identify and quantify the set of excesses in a particular design. This paper uses component properties and functional flow information to map and quantify the excess that exists within a system. Understanding the functional flow relationships between components allows for the bottlenecks at component interfaces to be identified. Those flows that do not limit the potential evolvability of a system can be removed from consideration, allowing for critical interface parameters to be highlighted and their capabilities quantified. The method is demonstrated on a consumer heat gun, where quantifying the excess within components allows for a reduced map to be created with irrelevant flows removed. Finally, changes to the system are explored to demonstrate how knowledge of component excess can be used to initially validate a proposed evolution.}, number={8}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Cansler, Ethan Z. and White, Samantha B. and Ferguson, Scott M. and Mattson, Christopher A.}, year={2016}, month={Aug} }
 @inproceedings{cansler_ferguson_mattson_2016, title={Exploring the relationship between excess and system evolutions using a stress-test}, DOI={10.1115/detc2015-47603}, abstractNote={Engineers understand that attaining a full service life can add value to an engineered system. Ensuring that this is possible requires that excess be embedded within the design to enable system evolution when new or changed requirements are placed on it during the service phase. However, since future needs are by definition unknown, knowing with certainty which excesses to embed is impossible. To address that challenge, this paper draws on an excess mapping method developed in previous work that demonstrated how to map component relationships based on excess interactions. This method is now used in a stress test approach to explore how a system design is affected when faced with various possible evolution scenarios. This study has two results: first, a judgment of whether the current system design possesses sufficient excess for it to respond to future needs. Second, quantitative estimates of excesses to add if the current design excess is judged to be insufficient. A demonstrative example is presented using a dart gun, which determines that the system as designed is likely adequate for a variety of possible future needs.}, booktitle={International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2015, vol 7}, author={Cansler, E. Z. and Ferguson, S. M. and Mattson, C. A.}, year={2016} }
 @inproceedings{shin_ferguson_2016, title={Modeling noncompensatory choices with a compensatory model for a product design search}, DOI={10.1115/detc2015-47632}, abstractNote={Market-based product design has typically used compensatory models that assume a simple additive part-worth rule. However, marketing literature has demonstrated that consumers use various heuristics called noncompensatory choices to simplify their choice decisions. This study aims to explore the suitability of compensatory modeling of these noncompensatory choices for the product design search. This is motivated by the limitations of the existing Bayesian-based noncompensatory mode, such as the screening rule assumptions, probabilistic representation of noncompensatory choices, and discontinuous choice probability functions in the Bayesian-based noncompensatory model. Results from using compensatory models show that noncompensatory choices can lead to distinct segments with extreme part-worths. In addition, the product design search problem suggests that the compensatory model would be preferred due to small design errors and inexpensive computational burden.}, booktitle={International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2015, vol 2A}, author={Shin, J. and Ferguson, S.}, year={2016} }
 @article{watson_allen_mattson_ferguson_2016, title={Optimization of excess system capability for increased evolvability}, volume={53}, ISSN={1615-147X 1615-1488}, url={http://dx.doi.org/10.1007/S00158-015-1378-X}, DOI={10.1007/S00158-015-1378-X}, number={6}, journal={Structural and Multidisciplinary Optimization}, publisher={Springer Science and Business Media LLC}, author={Watson, J. D. and Allen, J. D. and Mattson, C. A. and Ferguson, S. M.}, year={2016}, month={Jan}, pages={1277–1294} }
 @article{antonik_o'connor_ferguson_2016, title={Performance and Design Comparison of a Bulk Thermoelectric Cooler With a Hybrid Architecture}, volume={8}, ISSN={1948-5085 1948-5093}, url={http://dx.doi.org/10.1115/1.4032637}, DOI={10.1115/1.4032637}, abstractNote={This paper compares the economic viability and performance outcomes of two different thermoelectric device architectures to determine the advantages and appropriate use of each configuration. Hybrid thermoelectric coolers (TECs) employ thin-film thermoelectric materials sandwiched between a plastic substrate and form a corrugated structure. Roll-to-roll (R2R) manufacturing and low-cost polymer materials offer a cost advantage to the hybrid architecture at the sacrifice of performance capabilities while conventional bulk devices offer increased performance at a higher cost. Performance characteristics and cost information are developed for both hybrid and conventional bulk single-stage thermoelectric modules. The design variables include device geometry, electrical current input, and thermoelectric material type. The tradeoffs between cooling performance and cost will be explored, and the thermoelectric system configuration is analyzed for both hybrid and conventional bulk TECs.}, number={2}, journal={Journal of Thermal Science and Engineering Applications}, publisher={ASME International}, author={Antonik, Margaret and O'Connor, Brendan T. and Ferguson, Scott}, year={2016}, month={Mar} }
 @inproceedings{antonik_ferguson_o'connor_2016, title={Performance comparison of a bulk thermoelectric cooler with a hybrid device architecture}, DOI={10.1115/detc2015-47610}, abstractNote={This paper compares the economic viability and performance outcomes of two different thermoelectric device architectures to determine the advantages and appropriate use of each configuration. Hybrid thermoelectric coolers employ thin-film thermoelectric materials sandwiched between a plastic substrate and formed into a corrugated structure. Roll-to-roll manufacturing and low-cost polymer materials offer a cost advantage to the hybrid architecture at the sacrifice of performance capabilities while conventional bulk devices offer increased performance at a higher cost. Performance characteristics and cost information are developed for both hybrid and conventional bulk single-stage thermoelectric modules. The design variables include device geometry, electrical current input, and thermoelectric material type. The trade-offs between cooling performance and cost will be explored and the thermoelectric system configuration analyzed for both hybrid and conventional bulk thermoelectric coolers.}, booktitle={International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2015, vol 2b}, author={Antonik, M. and Ferguson, S. M. and O'Connor, B. T.}, year={2016} }
 @inproceedings{von hagel_ferguson_2016, title={Simulating variability of rework cost and market performance estimates in product redesign}, DOI={10.1115/detc2015-47598}, abstractNote={When considering the redesign of an existing product, designers must consider possible engineering and marketing ramifications. Ideal changes capture a large portion of the market and have a low risk of change propagation that results in reduced cost to the manufacturer. Engineering change tools such as the Change Prediction Method and market research models such as Hierarchical Bayes Mixed Logit allow designers to estimate the cost of the redesign process and market shares of preference. Variability in the inputs of the Change Prediction Method (impact and likelihood values) results in a range of redesign cost values. Assumptions regarding model form and the randomness used in model fitting also lead to variations when estimating market performance. When the variability associated with these techniques is considered, focus should shift from a point-estimate to a region-estimate. This paper explores the region-estimate produced for proposed redesigns when considering rework cost and market share of preference.}, booktitle={International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2015, vol 2A}, author={Von Hagel, K. A. and Ferguson, S. M.}, year={2016} }
 @article{sun_peavey_shelby_ferguson_brendan t. o'connor_2015, title={Heat shrink formation of a corrugated thin film thermoelectric generator}, volume={103}, ISSN={["1879-2227"]}, DOI={10.1016/j.enconman.2015.07.016}, abstractNote={A thin film thermoelectric (TE) generator with a corrugated architecture is demonstrated formed using a heat-shrink fabrication approach. Fabrication of the corrugated TE structure consists of depositing thin film thermoelectric elements onto a planar non-shrink polyimide substrate that is then sandwiched between two uniaxial stretch-oriented co-polyester (PET) films. The heat shrink PET films are adhered to the polyimide in select locations, such that when the structure is placed in a high temperature environment, the outer films shrink resulting in a corrugated core film and thermoelectric elements spanning between the outer PET films. The module has a cross-plane heat transfer architecture similar to a conventional bulk TE module, but with heat transfer in the plane of the thin film thermoelectric elements, which assists in maintaining a significant temperature difference across the thermoelectric junctions. In this demonstration, Ag and Ni films are used as the thermoelectric elements and a Seebeck coefficient of 14 μV K−1 is measured with a maximum power output of 0.22 nW per couple at a temperature difference of 7.0 K. We then theoretically consider the performance of this device architecture with high performance thermoelectric materials in the heat sink limited regime. The results show that the heat-shrink approach is a simple fabrication method that may be advantageous in large-area, low power density applications. The fabrication method is also compatible with simple geometric modification to achieve various form factors and power densities to customize the TE generator for a range of applications.}, journal={ENERGY CONVERSION AND MANAGEMENT}, author={Sun, Tianlei and Peavey, Jennifer L. and Shelby, M. David and Ferguson, Scott and Brendan T. O'Connor}, year={2015}, month={Oct}, pages={674–680} }
 @article{belt_von hagel_ferguson_2015, title={Navigating redesign and market desirability implications when considering increased product variety}, volume={26}, ISSN={["1466-1837"]}, DOI={10.1080/09544828.2015.1024209}, abstractNote={Current engineering change and market analysis tools provide discipline-specific feedback about the ramifications associated with offering increased product variety for an existing product. Engineering change tools provide ways to calculate and manage the risks associated with change propagation due to product modification, while strides in market research enable the modelling of consumer preferences for individual respondents. Yet, outcomes from these tools have not been adequately combined to explore the trade-off between engineering rework and consumer acceptance of the modified product. This work integrates the Change Prediction Method (CPM) and discrete choice analysis to simultaneously consider the engineering and business-side ramifications of offering increased variety by adding new product options. Outputs from the CPM are used to create a tradeoff plot between estimated market share gains and product cost when redesign effort is considered. This approach is applied to a gas grill problem to demonstrate how such trades can be considered when determining if a product option should be offered to increase product variety.}, number={7-9}, journal={JOURNAL OF ENGINEERING DESIGN}, author={Belt, Alex and Von Hagel, Kayla and Ferguson, Scott}, year={2015}, month={Sep}, pages={236–258} }
 @article{ilies_parkinson_seepersad_kokkolaras_ragsdell_papalambros_mistree_williams_rai_panchal_et al._2015, title={New perspectives on design automation: Celebrating the 40th anniversary of the ASME design automation conference}, volume={137}, DOI={10.1115/1.4030256}, abstractNote={The ASME Design Automation Conference and Committee (DAC) were initiated more than 40 years ago by a group of engineering visionaries to mark the dawn of the computer era in engineering design. Along the way, a strong and diverse community of academic, industrial, and government researchers have made the DAC community what it is today: a vibrant and energetic research community and a place to share the thoughts and ideas that fuel a common passion for engineering design automation (DA). To celebrate the legacy of the DAC and to spark common visions of the DAC’s future, the Design Automation Committee organized a 40th anniversary symposium at the 2014 ASME International Design Engineering Technical Conferences (IDETC). A capacity crowd of hundreds of DA researchers attended the program, which was organized into three segments. First, Kenneth Ragsdell, one of the founding members of the DAC, spoke of the founding of the conference and committee. He was followed by Panos Papalambros and Farrokh Mistree, who described the impact of 40 years of DA research and education along with some thoughts on the future of the DAC. The program ended with a series of six lightning talks from early career members of the DAC community offering their vision of emerging research opportunities in DA.}, number={5}, journal={Journal of Mechanical Design (New York, N.Y. : 1990)}, author={Ilies, H. and Parkinson, M. and Seepersad, C. C. and Kokkolaras, M. and Ragsdell, K. and Papalambros, P. and Mistree, F. and Williams, C. and Rai, R. and Panchal, J. and et al.}, year={2015} }
 @article{owoyele_ferguson_brendan t. o'connor_2015, title={Performance analysis of a thermoelectric cooler with a corrugated architecture}, volume={147}, ISSN={["1872-9118"]}, DOI={10.1016/j.apenergy.2015.01.132}, abstractNote={A thermoelectric (TE) cooler architecture is presented that employs thin film thermoelectric elements on a plastic substrate in a corrugated structure sandwiched between planar thermal interface plates. This design represents a hybrid of a conventional bulk TE device and an in-plane thin film TE design. This design is attractive as it may benefit from low cost thin-film processing in a roll-to-roll fashion onto low-cost plastics substrates while maintaining a cross-plane heat flux for large area applications and a geometry that assists in maintaining a significant temperature difference across the thermoelectric elements. First, the performance of a single thermocouple is analyzed and the effect of the parasitic heat loss through the plastic substrate is examined. The performance of an array of thermocouples is then considered and the effects of various geometric parameters are analyzed with particular focus on the packing density of thermoelectric legs. The results show that while the coefficient of performance (COP) is comparable to a conventional bulk element TE cooler, the cooling power density drops off dramatically with a decrease in stacking angle of the legs. A comparison is then made between the heat sink demands of the hybrid TE design and a conventional bulk TE device where it is found that the lower cooling power density of the hybrid TE results in a reduction of heat sink demands as compared to bulk TE modules. The modeled performance suggest that the hybrid TE device may be advantageous in low cooling power density applications over relatively large areas where the low-cost nature of the device is maximized and less elaborate heat sink designs work effectively, cumulatively improving cost competitiveness.}, journal={APPLIED ENERGY}, author={Owoyele, Opeoluwa and Ferguson, Scott and Brendan T. O'Connor}, year={2015}, month={Jun}, pages={184–191} }
 @inproceedings{von hagel_joglekar_ferguson_pankow_2015, title={Top down design using Bayesian network classifiers for composite panels}, booktitle={Proceedings of the American Society for Composites: Thirtieth Technical Conference}, author={Von Hagel, K. and Joglekar, S. and Ferguson, S. and Pankow, M.}, year={2015}, pages={468–475} }
 @article{tackett_mattson_ferguson_2014, title={A Model for Quantifying System Evolvability Based on Excess and Capacity}, volume={136}, ISSN={["1050-0472"]}, DOI={10.1115/1.4026648}, abstractNote={An important factor in system longevity is service-phase evolvability, which is defined as the ability of a system to physically transform from one configuration to a more desirable configuration while in service. These transformations may or may not be known during the design process, and may or may not be reversible. In a different study, we examined 210 engineered systems and found that system excess and modularity allow a system to evolve while in service. Building on this observation, the present paper introduces mathematical relationships that map a system's excess to that system's ability to evolve. As introduced in this paper, this relationship is derived from elastic potential-energy theories. The use of the evolvability measure, and other related measures presented herein, are illustrated with simple examples and applied to the design of U.S. Navy nuclear aircraft carriers. Using these relationships, we show that the Navy's new Ford-class aircraft carrier is measurably more evolvable than the Nimitz-class carriers. While the ability for systems to evolve is based on excess and modularity, this paper is focused only on excess. The mapping between modularity and evolvability is the focus of another work by the authors.}, number={5}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Tackett, Morgan W. P. and Mattson, Christopher A. and Ferguson, Scott M.}, year={2014}, month={May} }
 @inproceedings{denhart_gemmer_ferguson_mazzoleni_2014, title={A concept selection framework for early sorting of reconfigurable system designs}, DOI={10.1115/detc2013-13222}, abstractNote={A seven-step framework for sorting proposed concepts of system changes / reconfigurations is presented that seeks to characterize the overall ramifications on system architecture. This framework is intended for use immediately following a concept generation phase. The framework uses three simple questions: “What level of the system design does this concept apply to?” “What levels of the system design does the concept impact?” and “What is the severity of this impact?” A flowchart leads the designer through these questions and assigns each concept a classification from one to five based on the answers. Class one concepts have little to no impact on the rest of the system architecture. They can be included with little fear of massive change propagation and system redesign. Class five concepts carry large changes to system architecture and therefore should be included only if they can be shown to be highly beneficial, or if there remains enough design freedom such that the cost of changing the system architecture is minimal. Meanwhile, class five concepts are likely to have much higher potential to create revolutionary design. A case study is used to demonstrate the application of the sorting framework in the context of a Mars rover mission. Several example concepts are provided to illustrate key insights from the case study. Convergence of the framework is explored by comparing the authors’ results to a second test done by a new design team.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2013, vol 3B}, author={Denhart, J. and Gemmer, T. and Ferguson, S. and Mazzoleni, A.}, year={2014} }
 @misc{ferguson_olewnik_cormier_2014, title={A review of mass customization across marketing, engineering and distribution domains toward development of a process framework}, volume={25}, ISSN={["1435-6066"]}, DOI={10.1007/s00163-013-0162-4}, number={1}, journal={RESEARCH IN ENGINEERING DESIGN}, author={Ferguson, Scott M. and Olewnik, Andrew T. and Cormier, Phil}, year={2014}, month={Jan}, pages={11–30} }
 @article{foster_turner_ferguson_donndelinger_2014, title={Creating targeted initial populations for genetic product searches in heterogeneous markets}, volume={46}, ISSN={["1029-0273"]}, DOI={10.1080/0305215x.2013.861458}, abstractNote={Genetic searches often use randomly generated initial populations to maximize diversity and enable a thorough sampling of the design space. While many of these initial configurations perform poorly, the trade-off between population diversity and solution quality is typically acceptable for small-scale problems. Navigating complex design spaces, however, often requires computationally intelligent approaches that improve solution quality. This article draws on research advances in market-based product design and heuristic optimization to strategically construct ‘targeted’ initial populations. Targeted initial designs are created using respondent-level part-worths estimated from discrete choice models. These designs are then integrated into a traditional genetic search. Two case study problems of differing complexity are presented to illustrate the benefits of this approach. In both problems, targeted populations lead to computational savings and product configurations with improved market share of preferences. Future research efforts to tailor this approach and extend it towards multiple objectives are also discussed.}, number={12}, journal={ENGINEERING OPTIMIZATION}, author={Foster, Garrett and Turner, Callaway and Ferguson, Scott and Donndelinger, Joseph}, year={2014}, month={Dec}, pages={1729–1747} }
 @inproceedings{foster_denhart_ferguson_2014, title={Effects of feedback on design space exploration}, DOI={10.1115/detc2013-13243}, abstractNote={The ultimate goal of this research is to provide computer based educational software that exposes engineering students to design tradeoffs early in their undergraduate experience. This paper investigates two feedback elements for their ability to enhance those students’ understanding of the tradeoffs inherent in a water rocket propulsion design problem: 1) a Latin hypercube sample that allows the student to select a starting point and 2) sensitivity values that displayed local gradient information. Assessments are made using data logged during the students’ interaction with the software and a series of quizzes performed throughout the study. The results indicate that the sensitivity information improves the students’ ability to locate designs with good performance, while the Latin hypercube adversely affects the students’ ability to visualize the objective space.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2013, vol 1}, author={Foster, G. and Denhart, J. and Ferguson, S.}, year={2014} }
 @inproceedings{foster_ferguson_2014, title={Enhanced targeted initial populations for multiobjective product line optimization}, DOI={10.1115/detc2013-13303}, abstractNote={Initial populations for genetic algorithms are often created using randomly generated designs in an effort to maximize the genetic diversity in the design space. However, research indicates that the inclusion of solutions generated based on domain knowledge (i.e. non-random solutions) can notably improve the performance of the genetic algorithm with respect to solution performance and/or computational cost for convergence. This performance increase is extremely valuable for computationally expensive problems, such as product line optimization. In prior research, the authors demonstrated these improvements for product line design problems where market share of preference was the performance objective. Initial product line solutions were constructed from products that had the largest product-level utility for individual respondents. However, this simple product identification strategy did not adequately scale to accommodate the richer design problem associated with multiple objectives. This paper extends the creation of targeted initial populations to multiobjective product line design problems by using the objectives of the problem, instead of product level utility, to identify candidate designs. A MP3 player and vehicle feature packaging product line design problems are used to demonstrate this approach and assess the improvement of this modification.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2013, vol 3A}, author={Foster, G. and Ferguson, S.}, year={2014} }
 @article{archer_fang_ferguson_buckner_2014, title={Multi-Objective Design Optimization of a Variable Geometry Spray Fuel Injector}, volume={136}, ISSN={["1050-0472"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84903773146&partnerID=MN8TOARS}, DOI={10.1115/1.4026263}, abstractNote={This paper explores the simulation-based design optimization of a variable geometry spray (VGS) fuel injector. A multi-objective genetic algorithm (MOGA) is interfaced with commercial computational fluid dynamics (CFD) software and high performance computing capabilities to evaluate the spray characteristics of each VGS candidate design. A three-point full factorial experimental design is conducted to identify significant design variables and to better understand possible variable interactions. The Pareto frontier of optimal designs reveals the inherent tradeoff between two performance objectives—actuator stroke and spray angle sensitivity. Analysis of these solutions provides insight into dependencies between design parameters and the performance objectives and is used to assess possible performance gains with respect to initial prototype configurations. These insights provide valuable design information for the continued development of this VGS technology.}, number={4}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Archer, J. R. and Fang, Tiegang and Ferguson, Scott and Buckner, Gregory D.}, year={2014}, month={Apr} }
 @article{edwin_denhart_gemmer_ferguson_mazzoleni_2014, title={Performance Analysis and Technical Feasibility Assessment of a Transforming Roving-Rolling Explorer Rover for Mars Exploration}, volume={136}, ISSN={["1050-0472"]}, DOI={10.1115/1.4027336}, abstractNote={This paper explores a two state rover concept called the Transforming Roving-Rolling Explorer (TRREx). The first state allows the rover to travel like a conventional 6-wheeled rover. The second state is a sphere to permit faster descent of steep inclines. Performance of this concept is compared to a traditional rocker-bogie (RB) architecture using hi-fidelity simulations in Webots. Results show that for missions involving very rugged terrain, or a considerable amount of downhill travel, the TRREx outperforms the rocker-bogie. Locomotion of the TRREx system using a continuous shifting of the center of mass through “actuated rolling” is also explored. A dynamics model for a cylindrical representation of the rover is simulated to identify feasible configurations capable of generating and maintaining continuous rolling motion even on sandy terrain. Results show that in sufficiently benign terrain gradual inclines can be traversed with actuated rolling. This model allows for increased exploration of the problem's design space and assists in establishing parameters for an Earth prototype.}, number={7}, journal={JOURNAL OF MECHANICAL DESIGN}, author={Edwin, Lionel E. and Denhart, Jason D. and Gemmer, Thomas R. and Ferguson, Scott M. and Mazzoleni, Andre P.}, year={2014}, month={Jul} }
 @inproceedings{shaefer_ferguson_2014, title={Using a goal-switching selection operator in multi-objective genetic algorithm optimization problems}, DOI={10.1115/detc2013-13199}, abstractNote={This paper demonstrates how solution quality for multiobjective optimization problems can be improved by altering the selection phase of a multiobjective genetic algorithm. Rather than the traditional roulette selection used in algorithms like NSGA-II, this paper adds a goal switching technique to the selection operator. Goal switching in this context represents the rotation of the selection operator among a problem’s various objective functions to increase search diversity. This rotation can be specified over a set period of generations, evaluations, CPU time, or other factors defined by the designer. This technique is tested using a set period of generations before switching occurs, with only one objective considered at a time. Two test cases are explored, the first as identified in the Congress on Evolutionary Computation (CEC) 2009 special session and the second a case study concerning the market-driven design of a MP3 player product line. These problems were chosen because the first test case’s Pareto frontier is continuous and concave while being relatively easy to find. The second Pareto frontier is more difficult to obtain and the problem’s design space is significantly more complex. Selection operators of roulette and roulette with goal switching were tested with 3 to 7 design variables for the CEC 09 problem, and 81 design variables for the MP3 player problem. Results show that goal switching improves the number of Pareto frontier points found and can also lead to improvements in hypervolume and/or mean time to convergence.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2013, vol 3B}, author={Shaefer, D. and Ferguson, S.}, year={2014} }
 @article{foster_ferguson_2013, title={Exploring the Effectiveness of Using Graveyard Data When Generating Design Alternatives}, volume={13}, ISSN={["1944-7078"]}, DOI={10.1115/1.4024913}, abstractNote={The objective of this paper is to demonstrate that unique alternative designs can be efficiently found by searching the discarded data (or graveyard) from a multiobjective genetic algorithm (MOGA). Motivation for using graveyard data to generate design alternatives arises from the computational cost associated with real-time design space exploration of multiobjective optimization problems. The effectiveness of this approach is explored by comparing (1) the uniqueness of alternatives found using graveyard data and those generated using an optimization-based search, and (2) how alternative generation near the Pareto frontier is impacted. Two multiobjective case study problems are introduced—a two bar truss and an I-beam design optimization. Results from these studies indicate that using graveyard data allows for the discovery of alternative designs that are at least 70% as unique as alternatives found using an optimization-based alternative identification approach, while saving a significant number of functional evaluations. Additionally, graveyard data are shown to be better suited for alternative generation near the Pareto frontier than standard sampling techniques. Finally, areas of future work are also discussed.}, number={4}, journal={JOURNAL OF COMPUTING AND INFORMATION SCIENCE IN ENGINEERING}, author={Foster, Garrett and Ferguson, Scott}, year={2013}, month={Dec} }
 @inproceedings{foster_ferguson_2012, title={Assessing the effectiveness of using graveyard data for generating design alternatives}, DOI={10.1115/detc2011-48636}, abstractNote={Modeling to Generate Alternatives (MGA) is a technique used to identify variant designs that maximize design space distance from an initial point while satisfying performance loss constraints. Recent work has explored the application of this technique to nonlinear design problems, where the design space was investigated using an exhaustive sampling procedure. While computational cost concerns were noted, the main focus was determining how scaling and distance metric selection influenced alternative discovery. To increase the viability of MGA for engineering design problems, this work looks to reduce the computational overhead needed to identify design alternatives. This paper investigates and quantifies the effectiveness of using previously sampled designs, i.e. a graveyard, from a multiobjective genetic algorithm as a means of reducing computational expense. Computational savings and the expected error are quantified to assess the effectiveness of this approach. These results are compared to other more common “search” techniques; namely Latin hypercube samplings, grid search, and the Nelder-Mead simplex method. The performance of these “search” techniques are subsequently explored in two case study problems — the design of a two bar truss, and an I-beam — to find the most unique alternative design over a range of different thresholds. Results from this work show the graveyard can be used as a way of inexpensively generating alternatives that are close to ideal, especially nearer to the starting design. Additionally, this paper demonstrates that graveyard information can be used to increase the performance of the Nelder-Mead simplex method when searching for alternative designs.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2011, vol 5, pts A and B}, author={Foster, G. and Ferguson, S.}, year={2012}, pages={563–576} }
 @inproceedings{sullivan_ferguson_donndelinger_2012, title={Exploring differences in preference heterogeneity representation and their influence in product family design}, DOI={10.1115/detc2011-48596}, abstractNote={When using conjoint studies for market-based design, two model types can be fit to represent the heterogeneity present in a target market, discrete or continuous. In this paper, data from a choice-based conjoint study with 2275 respondents is analyzed for a 19-attribute combinatorial design problem with over 1 billion possible product configurations. Customer preferences are inferred from the choice task data using both representations of heterogeneity. The hierarchical Bayes mixed logit model exemplifies the continuous representation of heterogeneity, while the latent class multinomial logit model corresponds to the discrete representation. Product line solutions are generated by each of these model forms and are then explored to determine why differences are observed in both product solutions and market share estimates. These results reveal some potential limitations of the Latent Class model in the masking of preference heterogeneity. Finally, the ramifications of these results on the market-based design process are discussed.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2011, vol 5, pts A and B}, author={Sullivan, E. and Ferguson, S. and Donndelinger, J.}, year={2012}, pages={81–92} }
 @inproceedings{turner_ferguson_donndelinger_2012, title={Exploring heterogeneity of customer preference to balance commonality and market coverage}, DOI={10.1115/detc2011-48581}, abstractNote={Offering increased variety in a market is one method of capturing greater market share. However, we generally observe diminishing marginal returns in share as the size of the product line is increased. Leveraging commonality is a means of offsetting this constraint as it leads to reductions in manufacturing costs and build complexity. Product platforms strive to capitalize on the naturally occurring phenomena that yield commonality in a product line. The structure of design variable values of individually optimized products create opportunities for commonality in a bottom-up platform, while a top-down platform discovers opportunities for commonality through similarity in customer preferences. This paper explores the effect of changing the number of products, and commonality between those products, on market share. Results from designing a varying number of products independently are leveraged to create a bottom-up product platform. A top-down product platform approach based on a heterogeneous discrete choice model and a multiobjective genetic algorithm is presented that allow commonality decisions and product configuration to occur simultaneously. Using the platforming techniques presented in this paper, it is shown that the top-down platforming approach allows for more well-informed platformed design by providing knowledge of the tradeoff between commonality and market share.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2011, vol 5, pts A and B}, author={Turner, C. and Ferguson, S. and Donndelinger, J.}, year={2012}, pages={67–79} }
 @inproceedings{ferguson_olewnik_cormier_2012, title={Exploring marketing to engineering information mapping in mass customization: A presentation of ideas, challenges and resulting questions}, DOI={10.1115/detc2011-48742}, abstractNote={The paradigm of mass customization strives to minimize the tradeoffs between an ‘ideal’ product and products that are currently available. However, the lack of information relation mechanisms that connect the domains of marketing, engineering, and distribution have caused significant challenges when designing products for mass customization. For example, the bridge connecting the marketing and engineering domains is complicated by the lack of proven tools and methodologies that allow customer needs and preferences to be understood at a level discrete enough to support true mass customization. Discrete choice models have recently gained significant attention in engineering design literature as a way of expressing customer preferences. This paper explores how information from choice-based conjoint surveys might be used to assist the development of a mass customizable MP3 player, starting from 140 student surveys. The authors investigate the challenges of fielding discrete choice surveys for the purpose of mass customization, and explore how hierarchical Bayes mixed logit and latent class multinomial logit models might be used to understand the market for customizable attributes. The potential of using discrete choice models as a foundation for mathematically formulating mass customization problems is evaluated through an investigation of strengths and limitations.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2011, vol 5, pts A and B}, author={Ferguson, S. and Olewnik, A. and Cormier, P.}, year={2012}, pages={609–623} }
 @inproceedings{foster_holland_ferguson_deluca_2012, title={The creation of design modules for use in engineering design education}, DOI={10.1115/detc2012-71181}, abstractNote={Industry demands that graduating engineers possess the ability to solve complex problems requiring multidisciplinary approaches and systems-level thinking. Unfortunately, current curricula often focus on analytical approaches to problem solving. Further, adding courses focused solely on engineering design is often unachievable due to the large amount of material covered in today’s undergraduate engineering curricula. Combined, these prevent a comprehensive focus on engineering design education from being realized. To overcome these time and resource constraints, this paper proposes the use of computational modules within current courses. The investigators hypothesize that the modules would eliminate the repetitive analysis barrier in design problems, thus allowing for design-related experiences to be included earlier in the curricula as opposed to postponing it to a capstone experience. Four major hurdles that hinder successful integration of modules in current engineering courses are: a) engaging students such that they will want to use the modules; b) ensuring the modules are easy to use; c) reducing the complexity of deploying the modules into the classroom; and d) providing educational value. To address these issues, this paper treats the design of the modules as a product design problem. This paper presents the redesign process followed to improve two different design modules planned for implementation in the engineering curriculum at North Carolina State University. Additionally, this research indicates that using a formal redesign process enhances a module’s ability to overcome the hurdles listed above.}, booktitle={Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, vol 7}, author={Foster, G. and Holland, M. and Ferguson, S. and Deluca, W.}, year={2012}, pages={23–36} }
 @inproceedings{ferguson_tilstra_seepersad_wood_2010, title={Development of a changeable airfoil optimization model for use in the multidisciplinary design of unmanned aerial vehicles}, DOI={10.1115/detc2009-87482}, abstractNote={Complex systems need to perform in a variety of functional states and under varying operating conditions. Therefore, it is important to manage the different values of design variables associated with the operating states for each subsystem. The research presented in this paper uses multidisciplinary optimization (MDO) and changeable systems methods together in the design of a reconfigurable Unmanned Aerial Vehicle (UAV). MDO is a useful approach for designing a system that is composed of distinct disciplinary subsystems by managing the design variable coupling between the subsystem and system level optimization problems. Changeable design research addresses how changes in the physical configuration of products and systems can better meet distinct needs of different operating states. As a step towards the development of a realistic reconfigurable UAV optimization problem, this paper focuses on the performance advantage of using a changeable airfoil subsystem. Design principles from transformational design methods are used to develop concepts that determine how the design variables are allowed to change in the mathematical optimization problem. The performance of two changeable airfoil concepts is compared to a fixed airfoil design over two different missions that are defined by a sequence of mission segments. Determining the configurations of the static and changeable airfoils is accomplished using a genetic algorithm. Results from this study show that aircraft with changeable airfoils attain increased performance, and that the manner by which the system transforms is significant. For this reason, the changeable airfoil optimization developed in this paper is ready to be integrated into a complete MDO problem for the design of a reconfigurable UAV.}, booktitle={Proceedings of the ASME international design engineering technical conferences and computers and information in engineering conference, vol 5, pts a and b - 35th design automation conference}, author={Ferguson, S. and Tilstra, A. H. and Seepersad, C. C. and Wood, K. L.}, year={2010}, pages={57–68} }
 @article{ferguson_kasprzak_lewis_2009, title={Designing a family of reconfigurable vehicles using multilevel multidisciplinary design optimization}, volume={39}, ISSN={["1615-1488"]}, DOI={10.1007/s00158-008-0319-3}, number={2}, journal={STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION}, author={Ferguson, Scott and Kasprzak, Edward and Lewis, Kemper}, year={2009}, month={Aug}, pages={171–186} }