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1
Richards, Matthew G. "Multi-attribute tradespace exploration for survivability." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53217.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 235-249).
Survivability is the ability of a system to minimize the impact of a finite-duration disturbance on value delivery (i.e., stakeholder benefit at cost), achieved through (1) the reduction of the likelihood or magnitude of a disturbance, (2) the satisfaction of a minimally acceptable level of value delivery during and after a disturbance, and/or (3) a timely recovery. Traditionally specified as a requirement in military systems, survivability is an increasingly important consideration for all engineering systems given the proliferation of natural and artificial threats. Although survivability is an emergent system property that arises from interactions between a system and its environment, conventional approaches to survivability engineering are reductionist in nature. Furthermore, current methods neither accommodate dynamic threat environments nor facilitate stakeholder communication for conducting trade-offs among system lifecycle cost, mission utility, and operational survivability. Multi-Attribute Tradespace Exploration (MATE) for Survivability is introduced as a system analysis methodology to improve the generation and evaluation of survivable alternatives during conceptual design. MATE for Survivability applies decision theory to the parametric modeling of thousands of design alternatives across representative distributions of disturbance environments. To improve the generation of survivable alternatives, seventeen empirically-validated survivability design principles are introduced. The general set of design principles allows the consideration of structural and behavioral strategies for mitigating the impact of disturbances over the lifecycle of a given encounter.
(cont.) To improve the evaluation of survivability, value-based metrics are introduced for the assessment of survivability as a dynamic, continuous, and path-dependent system property. Two of these metrics, time-weighted average utility loss and threshold availability, are used to evaluate survivability based on the relationship between stochastic utility trajectories of system state and stakeholder expectations across nominal and perturbed environments. Finally, the survivability "tear(drop)" tradespace is introduced to enable the identification of inherently survivable architectures that efficiently balance performance metrics of cost, utility, and survivability. The internal validity and prescriptive value of the design principles, metrics, and tradespaces comprising MATE for Survivability are established through applications to the designs of an orbital transfer vehicle and a satellite radar system.
by Matthew G. Richards.
Ph.D.
2
Cunio, Phillip M. "Tradespace model for planetary surface exploration hopping vehicles." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76088.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.CD-ROM contains files in .m and .xls formats.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 243-257).
Robotic planetary surface exploration, which has greatly benefited humankind's scientific knowledge of the solar system, has to date been conducted by sedentary landers or by slow, terrain-limited rovers. However, there are other types of vehicles which can conduct planetary surface exploration. One of these is hopping vehicles, which do not require fluid contact or ground contact in order to move, but instead propulsively balance thrust from their engines against gravity to propel themselves over the surface. Hopping vehicles are still a nascent technology, however, and no spaceborne hopping vehicles have yet flown. In order to bring hopping vehicles into the decision space for planetary surface exploration missions, in this thesis we provide a framework to understand hopping vehicles' key characteristics and advantages, as well as a tradespace model to size hopping vehicles based on mission characteristics. The tradespace model takes user-input mission requirements, including target planetary body, scientific payload, and a detailed flight profile, and produces a subsystem-level model of a hopping vehicle which can complete the mission. Information on the operational profile and lifecycle costs of the hopping vehicle is also produced. The tradespace model also permits users to capture results from one model run and compare them to other model runs, or to results produced by other models. In this thesis, the tradespace model is described, and initial tradespace investigation is performed using the model. Finally, lessons learned are summarized and suggestions are offered for future research. The thesis closes with a summation of the potential offered by hopping vehicles for planetary surface exploration missions in the decades to come.
by Phillip M. Cunio.
Ph.D.
3
Chattopadhyay, Debarati. "A method for tradespace exploration of systems of systems." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50607.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2009.Includes bibliographical references (p. 211-215).
Systems of Systems (SoS) are a current focus of many organizations interested in integrating assets and utilizing new technology to create multi-component systems that deliver value over time. The dynamic composition of SoS along with the managerial independence of their component systems necessitates systems engineering considerations and methods beyond those of traditional systems engineering, particularly for SoS concept design. Qualitative and heuristic-based guidance is available in the literature, but there is a need for a method that will allow decision makers to quantitatively compare diverse multi-concept SoS designs on an equal basis in order to select value robust designs during concept exploration. Development of a quantitative method for SoS conceptual design will enable the consideration of many more architecture options than is possible through qualitative methods alone, facilitating a more complete exploration of a SoS design space. In this thesis, a quantitative method for SoS conceptual design, known as System of Systems Tradespace Exploration Method (SoSTEM), is presented. This method is based on the existing Dynamic Multi-Attribute Tradespace Exploration (MATE) which is a formal methodology for tradespace exploration during system design that allows the decision maker to make trades between both stakeholder preferences and systems early in the design process and includes the consideration of dynamic issues such as unarticulated stakeholder preferences and changing system context.
(cont.) In SoSTEM, SoS-level performance attributes are generated through a combination of component system attributes and system latent value, allowing the generation of SoS tradespaces where multi-concept architectures can be compared on the same performance and cost basis. This method allows the SoS designer to distinguish between component systems having high likelihood of participation in the SoS and those with lower likelihood of participation, based on the level of 'Effective Managerial Authority' that the SoS designer has over the component. SoSTEM is demonstrated through application to two case studies, an Operationally Responsive System for Disaster Surveillance and Satellite Radar.
by Debarati Chattopadhyay.
S.M.
4
Ross, Adam Michael 1977. "Managing unarticulated value : changeability in multi-attribute tradespace exploration." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35089.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2006.Includes bibliographical references (p. 305-310).
A framework for creating value robust systems in the face of changing value perceptions during the architecture and design of systems is proposed. Both unarticulated value, that which is not explicitly communicated to system designers, and dynamic value, that which changes over time, are used to motivate the dynamic Multi-Attribute Tradespace Exploration (MATE) process. Value can be represented as decision maker perceived attributes, which can be classified according to the ease by which the system can display them. The attribute class spectrum from least to most costly ranges from articulated, class 0 attributes, to inaccessible value, class 4 attributes. Supporting the value-adding approach, the system property concepts of flexibility, adaptability, rigidity, robustness, scalability, and modifiability are proposed to be different aspects of the same concept: changeability. A quantification of changeability is shown to be the Filtered Outdegree of a design within a networked tradespace formed through explicit consideration of transition paths between design instantiations. A focus on designing not only for value, but for changeability as well, leads to the concept of path enabling variables, whose purpose is to increase change paths or decrease cost for change.
(cont.) Value robustness is shown to be achieved through either passive or active means. Passive value robustness can be quantified as the Pareto Trace number of a design, reflecting the number of contexts within which a particular design is determined to be best value at a given level of resource expenditure. Active value robustness is achieved through a strategy of pursuing designs with increased changeability and accessibility to likely high value regions of a tradespace. Supporting the process, the Design-Value Matrix and the Rule-Effects Matrix help system designers visualize the key factors for creating dynamic value-generating systems by capturing the important relationships between decision makers, design variables, attributes, path enablers, and resources. The dynamic MATE process is applied to two real system cases including the Joint Direct Attack Munition (JDAM) and the Terrestrial Planet Finder (TPF). The framework is shown to be applicable at both quantitative and qualitative levels, giving insight into assessing and designing for changeability and value robustness for systems.
by Adam Michael Ross.
Ph.D.
5
Davison, Peter Leslie. "Tradespace exploration for space system architectures : a weighted graph framework." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90773.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 167-172).
Many systems undergo significant architecture-level change during their lifecycles as a result of exogenous system disturbances (e.g. budget reduction or changes in stakeholder requirements), failure to develop critical technologies, or planned evolution of the system over time. Given the high cost in terms of resources, schedule, and performance of making these changes during system development or operations, it is essential to make these decisions with a thorough understanding of the available options and costs associated with different architecture changes. The analysis of such decisions stems from an understanding of the relationships between architectures in the tradespace, however most architecture tradespace generation tools focus on the modeling and evaluation of individual architectures rather than on modeling how different architectures are related to one another. In this thesis we propose a framework for modeling these relationships based on the evaluation of a pre-existing tradespace for the purpose of analyzing architecture change decisions. This modeling framework is used to discover and evaluate evolutionary pathways through a disorganized tradespace: a process we call tradespace exploration. These pathways can be used to assess architecture selection decisions and to quantitatively compare architecture change decisions against one another, providing a decision analysis tool for system architects. At the core of the framework is the generation of a directed, weighted 'tradespace graph' that serves as a model of the architecture decision making process. Vertices in the tradespace graph are defined by pairings of architectures from the tradespace with asset portfolios, which are the sets of the common elements shared between multiple architectures. The existence of an edge in the graph, which represents a feasible decision to transform from one architecture to another, is determined by the relationship between the asset portfolios of the two vertices. The weight of an edge represents the cost of the corresponding architecture change, with the sum of edge weights along a path through the tradespace representing the total development cost of the architecture evolution. We apply this tradespace exploration framework to two pre-existing architecture tradespaces: the first being the 'HEXANE' tradespace of in-space transportation infrastructures for human exploration beyond low Earth orbit, and the second being the 'SCaN' tradespace of space-based communications network architectures for the relay of data between ground stations and user spacecraft. Using a variety of domain-independent analysis tools and graph search algorithms, we generate several results of potential value to system architects for both applications.
by Peter Leslie Davison.
S.M.
6
Derleth, Jason Edward 1970. "Multi-attribute tradespace exploration and its application to evolutionary acquisition." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/82702.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2003.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 144).
by Jason Edward Derleth.
S.M.
7
Ong, Ke Wei Joel. "Applying tradespace exploration methods for the design of value-robust microgrids." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/110141.
Повний текст джерелаАнотація:
Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, School of Engineering, System Design and Management Program, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 90-94).
Microgrids enhance resilience in power distribution by providing the capability to be islanded from the utility grid and sustain electricity delivery using distributed energy resources. Microgrids are also able to accommodate a higher mix of renewable energy sources that bring about reduced carbon emissions. However, the increasing complexities that come with decentralizing power generation and the integration of cyber elements pose new challenges in making design decisions. In this thesis, two tradespace based methods are proposed for choosing value-robust microgrid designs during the conceptual design stage. A value-robust design is one that is able to sustain delivery of perceived value to stakeholders, even when subjected to changes in contexts and needs. Multi-Attribute Tradespace Exploration (MATE) enables decision makers to evaluate a large number of design alternatives against utility and expense metrics that capture the stakeholder-perceived value. A full tradespace exploration avoids premature fixation on local point solutions and provides a more in-depth appreciation of the design space. Epoch-Era Analysis (EEA) provides a dynamic perspective of the system to enable the evaluation of value robustness across time periods with changing contexts and value expectations. The value robustness of a design can be quantified by analyzing tradespaces across different value-centric time periods or epochs. Designs that are found to exhibit high value robustness can be identified as candidates for detailed design. A constructed case study of a military microgrid is presented to demonstrate the use of MATE and EEA to find highly value-robust designs. While traditional design approaches tend to limit decision-making to a choice among given alternatives, MATE and EEA focus on the fundamental values of decision makers, allowing them to generate alternatives and discover high value designs.
by Ke Wei Joel Ong.
S.M. in Engineering and Management
8
Fitzgerald, Matthew Edward. "Framing tradespace exploration to improve support for multiple-stakeholder decision making." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105555.
Повний текст джерелаАнотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis. Vita.
Includes bibliographical references (pages 326-339).
As modern engineering projects increase in size and complexity, they have also tended to increase the number of people affected, thus expanding the set of involved stakeholders. The majority of research in tradespace exploration (TSE), as a paradigm for solving complex design problems, has focused on the analysis of the space of alternatives with the goal of uncovering design choices that are optimal or near-optimal. These designs feature desirable combinations of attributes for a given system stakeholder, including technical attributes, cost, and, more recently, -ilities. Less tradespace research has been devoted to the multi-stakeholder problem, in which there are multiple parties with different desired attributes, who must agree on a single design selection in order to proceed with development. Many standard value-measuring techniques, such as utility theory, operate on individuals only and have been shown to break down when used to combine the preferences of groups. Because of these limitations, multi-stakeholder tradespace exploration (MSTSE) has largely relied on the best practices for individual tradespace exploration, with all stakeholders using those methods in parallel. This parallel exploration has the goal of uncovering as many interesting or desirable alternatives as possible, empowering stakeholders to make an educated decision on how best to negotiate with their counterparts. The group decision problem, however, is not just a series of individual decisions and must incorporate interpersonal dynamics and psychological considerations of what makes a "good" decision, and what constitutes a "fair" solution in the minds of the participants. This thesis describes a research effort to develop the foundations of MSTSE by incorporating fundamental insights from the negotiation and framing literatures. A literature review is used to show that TSE is naturally aligned with the goals of productive negotiation. The framing of data in MSTSE is confirmed, via controlled experiment, to have impacts on negotiation which can be controlled through the visualizations given to the participating stakeholders. A combination of practitioner interviews, analysis of procedures for modern systems engineering methods, and case studies (on aerospace and transportation infrastructure systems) is used to create recommendations for applying MSTSE and demonstrate the new types of insights that can be achieved by doing so, beyond those of prior analyses.
by Matthew Edward Fitzgerald.
Ph. D.
9
Prindle, Aaron L. "Tradespace exploration in the Cloud : incorporating cloud technologies into IVTea Suite." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100686.
Повний текст джерелаАнотація:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 109-112).
IVTea Suite is a tradespace exploration and analysis tool designed to allow users to gain insights into potential designs for large scale systems, and enables the analysis of tradeoffs, both static and dynamic, inherent in the selection of particular designs from amongst many possibilities. IVTea Suite's current architecture limits its ability to operate on large datasets, as well as prevents it from calculating important computationally complex lifecycle metrics needed to select value sustaining designs. This thesis analyses the current state of cloud technologies and provides solutions on how IVTea Suite can overcome its current architectural limitations. As a demonstration of potential new capabilities, the multi-era affordability with change paths problem, previously not solvable, is addressed using Markov decision processes and cloud technology. Additionally, this work describes a cloud framework that can be used in the future, which provides the potential ability to solve the multi-arc change paths problem for datasets previously too large to evaluate.
by Aaron L. Prindle.
M. Eng.
10
La, Tour Paul A. (Paul Alexis). "Combining tradespace exploration with system dynamics to explore future space architectures." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106593.
Повний текст джерелаАнотація:
Thesis: Ph. D. in Engineering Systems, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, 2016.Some pages printed landscape orientation. Cataloged from PDF version of thesis.
Includes bibliographical references (pages 342-351).
This work proposes a merger of Tradespace Exploration with System Dynamics modeling techniques in a complementary approach. It tests the value of this mixed method for modeling the multiplicity of inputs and complexity of feedback loops that affect the cost, schedule and performance of satellite constellations within the Department of Defense. The resulting simulation enables direct comparison of the effect of changing architectural design points and policy choices with respect to satellite acquisitions and fielding. A generation-over-generation examination of policy choices is made possible through the application of soft systems modeling of experience and learning effects. The resulting model enables examination of possible futures given variations in assumptions about both internal and external forces on a satellite production pipeline. This thesis performs a policy analysis examining the current path of the Global Positioning System acquisition and compares it to equivalent position navigation and timing capability delivered through a variety of disaggregated options while varying: design lives, production quantities, non-recurring engineering and time between generations. The extensibility of this technique is investigated by adapting the model to the mission area of Weather and Climate Sensing. This thesis then performs a policy analysis examining different disaggregated approaches for the Joint Polar Satellite, focusing on the impact of complexity. Discussion of factors such as design choices, context variables, tuning variables, model execution and construction is also included.
by Paul A. La Tour.
Ph. D. in Engineering Systems
11
Do, Sydney. "Towards Earth independence - tradespace exploration of long-duration crewed Mars surface system architectures." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105554.
Повний текст джерелаАнотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 577-599).
In recent years, an unprecedented level of interest has grown around the prospect of sending humans to Mars for the exploration and eventual settlement of that planet. With the signing of the 2010 NASA Authorization Act, this goal became the official policy of the United States and consequently, has become the long-term objective of NASA's human spaceflight activities. A review of past Mars mission planning efforts, however, reveals that while numerous analyses have studied the challenges of transporting people to the red planet, relatively little analyses have been performed in characterizing the challenges of sustaining humans upon arrival. In light of this observation, this thesis develops HabNet - an integrated Habitation, Environmental Control and Life Support (ECLS), In-Situ Resource Utilization (ISRU), and Supportability analysis framework - and applies it to three different Mars mission scenarios to analyze the impacts of different system architectures on the costs of deploying and sustaining a continuous human presence on the surface of Mars. Through these case studies, a number of new insights on the mass-optimality of Mars surface system architectures are derived. The most significant of these is the finding that ECLS architecture mass-optimality is strongly dependent on the cost of ISRU - where open-loop ECLS architectures become mass-optimal when the cost of ISRU is low, and ECLS architectures with higher levels of resource recycling become mass-optimal when the cost of ISRU is high. For the Martian surface, the relative abundance of resources equates to a low cost of ISRU, which results in an open-loop ECLS system supplemented with ISRU becoming an attractive, if not dominant surface system architecture, over a range of mission scenarios and ISRU performance levels. This result, along with the others made in this thesis, demonstrates the large potential of integrated system analyses in uncovering previously unseen trends within the Mars mission architecture tradespace. By integrating multiple traditionally disparate spaceflight disciplines into a unified analysis framework, this thesis attempts to make the first steps towards codifying the human spaceflight mission architecting process, with the ultimate goal of enabling the efficient evaluation of the architectural decisions that will shape humanity's expansion into the cosmos.
by Sydney Do.
Ph. D.
12
Nickel, Julia S. M. Massachusetts Institute of Technology. "Using multi-attribute tradespace exploration for the architecting and design of transportation systems." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/63022.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 241-249).
The field of Engineering Systems maintains that fundamental engineering principles exist, which apply across different domains of complex socio-technical systems. In this thesis, a state-of-the art decision and design evaluation method developed using aerospace cases, Multi-Attribute Tradespace Exploration (MATE), is applied for the first time to a transportation design problem. Through the application process across domains, differences between the aerospace and transportation domain are characterized: (1) a "mission objective" has not emerged as a welldefined, integral concept for transportation project planning in the same way it did in the military and space communities; (2) a simple stakeholder structure for the purpose of the analysis is not a reasonable assumption, (3) inheritance (legacy structures and legacy expectations) in transportation planning brings with it the stickiness of the status quo and people's attachment to things they possess; (4) several cost types exist in addition to monetary costs, e.g. harmful effects to life and spending of scarce resources (time, money); (5) decisions about the welfare of stakeholders in transportation planning are inextricably linked to technical decisions. It follows that fundamental engineering systems design principles need to be general enough to encompass these domain differences. Decisions about the welfare of stakeholders (public, future generations, environment) by a legitimized representative decision maker raise the question about the desirability of prescriptive guiding principles for decision making, in order to ensure consideration for the represented constituency when their interests need to be traded off with personal and organizational interests of the decision maker. Decision makers themselves seek such guidance to help them in trading off and justifying decisions about multiple competing goals in complex situations. One established method to provide such guidance is Cost-Benefit Analysis (CBA). CBA is a central, established, prescriptive evaluation method used in several domains, including transportation. In order to compare insights gained through the emerging method MATE and the established method CBA, two case studies, a Chicago Airport Express and a High-Speed Rail link between Portugal and Spain, are evaluated using those two methods. CBA assumes a broad view over all affected stakeholders, decision making or not, and seeks to ensure that net benefits to society outweigh net costs. MATE seeks to best meet decision makers' expectations for a system. Attributes (tangible and intangible) that are valuable to individual stakeholders, but not to society as a whole, are captured in the value-based approach in MATE. They are purposefully excluded in CBA. A challenge that the value-based approach in MATE brings about are framing issues that can arise when utility theory is applied to decision making stakeholders who have mandates to represent other stakeholders. For both aerospace and transportation domains, political vision and technical understanding of properties of different designs are important for decision making. A real feedback cycle between goal capture and low-fidelity technical modeling of different design options as suggested in MATE does not seem to exist in transportation planning. MATE seems useful as a tool to support improved communication about system expectations and technical options. Future research will need to address how value-based attribute capture can be performed in the typical complex stakeholder structure of transportation systems. Recognizing that problems of equity and value judgments are an inherent part of (some) technical decisions, the question of how to support a decision maker in expressing those attributes (even if difficult and controversial) and understanding different design concepts' impact on technical properties becomes part of the design engineer's job.
by Julia Nickel.
S.M.
13
Diller, Nathan P. (Nathan Philip) 1978. "Utilizing Multiple Attribute Tradespace Exploration with Concurrent Design for creating aerospace systems requirements." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/83680.
Повний текст джерела
14
Shougarian, Narek Rouben. "Towards concept generation and performance-complexity tradespace exploration of engineering systems using convex hulls." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108924.
Повний текст джерелаАнотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 239-249).
This thesis examines tradeoffs between performance and complexity in the context of future aircraft engine architectures and a reconfigurable mobile device. Traditionally aircraft/engine system architecture selection has been conducted via expert suggestion, evaluation and down-selection of alternatives. This work proposes a convex hull-based computational approach to generating architectures that uses flows at subsystem interfaces to enforce feasibility of connections between components. Convex hulls at component interfaces are used to represent the entire space of possible flows that they can exhibit. This is combined with automatic nonlinear model synthesis, optimization and complexity quantification to create an approach that allows the designer to trade the number of false negatives and the size of the design space. A false negative is an architecture that is not generated or once generated is discarded from consideration erroneously as an infeasible one, even though once implemented it would perform the intended function at the intended level of performance adequately. 71 aircraft engine architectures were generated and optimized for minimum uninstalled thrust specific fuel consumption, including families of distributed/non-distributed turboelectric architectures. Families of distributed turboelectric propulsion systems in which some fans are driven electrically and some are driven mechanically were found to exhibit lower uninstalled fuel consumption than current designs due to high efficiency & power to weight ratio of mechanical power transfer and the propulsive efficiency improvements despite losses in electrical power transfer. A simplified correction for the weight penalty associated with these architectures however shows that to gain overall benefit in fuel consumption, boundary layer ingestion will be required. While the literature typically examines individual concepts, in this case a portfolio of concepts was generated and can be leveraged in new aircraft configuration design studies in the future. The second major finding of this work is that the set of generated distributed turboelectric architectures are approximately 1.2 to 2 times as complex as current engine architectures using a complexity metric from the literature that takes into account complexity of components, interfaces and the network of connections between them. 21,168 reconfigurable mobile device architectures were generated and simulated. This number is larger than that for engines due to the presence of more optional components for the reconfigurable mobile device and the fact that this analysis was carried out at only one level abstraction, whereas two were used for the engine. The first finding was that only approximately 2% of possible architectures were feasible. The second finding was that, while no individual architecture was exceedingly complex compared to current devices, the aggregate complexity of the full set of 21,168 architectures was very high. Moreover, the sparse space of feasible architectures meant that in addition to conducting virtual/physical verification and validation of predicted feasible device configurations, a platform owner would have to guide users through a vast architectural space to their desired configuration.
by Narek Rouben Shougarian.
Ph. D.
15
Walker, Johnathan C. (Johnathan Clyde). "Multi-attribute tradespace exploration for US Navy surface ship survivability: a framework for balancing capability, survivability, and affordability." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104296.
Повний текст джерелаАнотація:
Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 123-126).
In a political environment of austerity, the importance of understanding the design tradeoffs for new naval ship concept designs cannot be understated. A combination of a tightened shipbuilding budget, large high-priority procurement programs, and an emphasis on affordability will require high level tradeoffs to be made in future ship programs. Understanding tradeoffs in naval ship capability and survivability for the sake of affordability early in concept ship design gives Navy leadership real options for affordable ships and reduces the likelihood of detailed design changes late in the acquisition process. In the naval ship design process capability and affordability are typical "ility" tradeoffs made in traditional tradespace exploration. Ship designers must consider survivability as a third dimension independent of capability and cost. A specific ship system can be costly and improve survivability in a design but not deliver a level of desired capability. This thesis proposes a framework based on existing methodologies to perform tradespace exploration by iteratively determining a concept naval ship design's capability, survivability, and cost across large tradespaces of thousands of concepts. The process determines an optimal set of designs using multi-dimensional Pareto-optimization methods. This thesis also demonstrates methods to navigate the space bound by the optimized set of designs so tradeoffs can be made while preserving the optimal balance of capability, survivability, and cost. Survivability-cost relationships are developed with specific design requirements to provide insight into the amount of investment required to improve naval ship survivability. Understanding capability-survivability-cost tradeoffs ultimately informs a ship designer the premium that must be paid for increased survivability for a desired level of capability.
by Johnathan C. Walker.
Nav. E.
S.M.
16
Roark, Henry H. III. "Value centric approach to target system modularization using multi-attribute tradespace exploration and network measures of component modularity." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76570.
Повний текст джерелаАнотація:
Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 101-105).
Deciding where to modularize a system can have long-term impact on that systems value over its entire lifecycle. The modularity of a system can impact the systems flexibility, evolvability, scalability, mass, costs, and development schedule. Making these modularization decisions is a key job of the system architect. There exists a need to provide the system architect tools that will help focus modularization efforts on the areas of the system that are most likely to provide value to stakeholders of the system. Using a terrestrial vehicle as a case study, an approach is developed that links component modularity to system design variables which are likely to change levels. The approach utilitizes Multi-Attribute Tradespace Exploration, Multi-Epoch Analysis, and network measures of component modularity to identify components which are most likely to need to change as well as the components ability to make a modularity change. It is found that the tools utilized can be successfully linked to provide early development phase information about value-centric system modularizations; the approach does require a network representation of the system earlier in the design cycle than it may be typically available. Using explicit knowledge, the approach developed can focus designers modularization efforts on the elements of the system that may need to change to accommodate changes in decision makers preferences, use contexts, or epoch contexts. The approach developed can aid the system architect modularizing a system so as to create a high amount of leverage for a systems stakeholders.
by Henry H. Roark, III.
S.M.in Engineering and Management
17
Ross, Adam Michael 1977. "Multi-attribute tradespace exploration with concurrent design as a value-centric framework for space system architecture and design." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/82788.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2003.Includes bibliographical references (p. 155-158).
by Adam Michael Ross.
S.M.
18
Spaulding, Timothy J. (Timothy James) 1979. "Tools for evolutionary acquisition : a study of Multi-Attribute Tradespace Exploration (MATE) applied to the Space Based Radar (SBR)." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/82703.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2003.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Statement of responsibility on t.p. reads: 2nd Lieutenant Timothy J. Spaulding, USAF.
Includes bibliographical references (p. 139-142).
by Timothy J. Spaulding.
S.M.
19
Menezes, Jeffrey Louis. "Use of isoperformance, constraint programming, and mixed integer linear programing for architecture tradespace exploration of passive Optical Earth Observation Systems." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119313.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, In conjunction with the Leaders for Global Operations Program at MIT, 2018.Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management 2018 In conjunction with the Leaders for Global Operations Program at MIT
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 147-150).
This thesis presents work performed during the course of an internship at An Aerospace Company (AAC) and research performed at Massachusetts Institute of Technology (MIT) Lincoln Laboratory as part of a fellowship. Both efforts entailed the development of architecture tradespace exploration models for space systems. The tradespace exploration model developed at AAC, called the Earth Observation Architecture Isoperformance Model (EO-AIM), uses automation techniques, isoperformance, and constraint programming to rapidly construct potential space-based passive optical EO sensor architecture concepts which meet a given set of customer requirements. Cost estimates are also generated for each sensor concept via integration with stakeholder-trusted cost modeling software allowing for cost to be treated as both an independent variable and consequence when evaluating various architecture solutions. The EO-AIM then uses simple algorithms to identify potential satellite bus options for hosting each sensor architecture in orbit. The total cost of populating an entire constellation based on the sensor architecture is finally estimated using cost estimates for the sensor, satellite bus, and the best launch vehicle option capable of lifting the satellite(s) to orbit. In general, the EO-AIM seeks to bolster's AAC's capabilities for conducting architecture trade space exploration and initial proposal development given advancements in satellite bus, launch vehicle, and sensing technologies. The tradespace exploration model developed at MIT Lincoln Laboratory is a satellite network mixed integer linear program (MILP) which is used for making system architecture decisions and estimating final architecture cost. The satellite network MILP is formulated as both an assignment problem and a network maximum flow problem which must send sensor generated data to a ground user. Results of the MILP vary with the selected objective function and provide insights on the potential benefits of architecture decisions such as sensor disaggregation and the utility of introducing additional communication nodes into existing networks. The satellite network MILP is also capable of verifying network data volume throughput capacity and providing an optimized link schedule for the duration of the simulation. Overall, the satellite network MILP model explores the general problem of optimizing use of limited resources for a given space-based sensor while ensuring mission data needs are met. It is a higher fidelity alternative to the simple satellite bus and launch vehicle compatibility algorithm used in EO-AIM. Both models are shown to improve architecture tradespace exploration of space-based passive-optical EO systems. With a simple demonstration, it is exhibited that using the EO-AIM can increase sensor architecture concepts generated by a factor of ten or more by creating all feasible sensor architecture concepts given user inputs and settings. Furthermore, the use of the satellite network MILP to examine alternative network architecture options for NASA's HyspIRI mission resulted in a system architecture with 20% higher data throughput for marginally less cost.
by Jeffrey Louis Menezes.
S.M.
M.B.A.
20
Tan, Puay Siang. "Teamwork behaviors at mesoscale : meaningful explorations of tradespace during project design." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118514.
Повний текст джерелаАнотація:
Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 112-113).
The increasing complexity in Systems of Systems requires Teams of Teams (TofT) from different functional domains to work together. Rather than focusing on individuals and teams (the microscale) or total projects and portfolios (the macro-scale), this research aims to better detect and understand the teamwork behaviors at the meso-scale, the behaviors and interactions amongst the team of teams. Using the Project Design approach, Design Groups representing a TofF participated in a model- based simulation experiment to reduce the cost and duration of an implementation project for an autonomous vehicle. Design Groups were provided specific instructions to either inhibit or promote communications as they worked together to make changes to the Project Model of the autonomous vehicle, after which they can perform simulation to obtain the project outcome in terms of cost and schedule. In this experiment the teamwork was instrumented, detecting attention allocation, changes, and resulting exploration of the project tradespace. A quantifiable ranking methodology was developed to evaluate the performance of the Design Groups based on the iterations made as they explored and simulated the project model. This methodology ranked the Design Group by 1) higher number of outcomes obtained at the Pareto Frontier of the tradespace and 2) outcomes in earlier Pareto Frontiers. Two indicators of Team Performance - Number of Iterations and Communications Behaviors of the Design Group - were studied where correlations were found to be weak. Tree Diagrams were generated to visualize the tradespace exploration of the Design Group by mapping the iterations performed in sequence and provided details on the changes type made to the project model. A Chunking Process dovetailed the Tree Diagrams to detect the meaningful explorations of the tradespace by each Design Group. Each Meaningful Exploration was segmented into "Chunks" which were further classified into blocks with specific number of changes. This study provided further insights on the coherence in which changes were made along the path of tradespace explorations. Information from the Chunking Process is used to determine how "focused" the Design Groups were in the decision making process. Three ratios were suggested, namely, Ratio of Focus Score to Total Iterations with Changes, Ratio of Focused Iterations to Total Iterations with Changes and Ratio of Meaningful Changes Block to Total No of Chunks. The research concludes with using these ratios as an indicator of coherence and potential sensors to detect presence of strategy in teams in future experiments. The key insights from this research is that the Project Design Approach provides the same baseline project model for all Design Groups that enables a fair and quantifiable ranking of team performance. In instrumenting the experiment, collective group responses to qualitative data is preferred over individual responses for a more representative analysis of the teamwork behaviors. Another insight is that tradespace explorations by the Design Groups do not occur in unilateral fashion. Thus, it is important to have a visual image of the changes made along the tradespace exploration to identify the meaningful exploration paths. Segmenting these meaningful exploration paths provides the means for measuring coherence of the Design Groups in their decision making process. Next steps for future experiments include embedding in the Project Design software to collect the group responses required for quantitative analysis as the experiment is on-going. The measurement of team learning effects is suggested for future research by having a two-step data collection process in which the same experiment can be conducted as a first step and having the same participants to repeat another Project Design Challenge several months later in the second step to evaluate the team performance.
by Tan Puay Siang.
S.M. in Engineering and Management