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This paper develops a flexibility management framework for space logistics mission planning under uncertainty through decision rules and multistage stochastic programming. It aims to add built-in f...

This paper studies and develops multiple auction-based algorithms for resource exchange among decentralized systems in federated networks with distributed computational resources. Decentralized resource owners and users use processing, storage, and communication units to perform the available computational tasks at each time step while an auctioneer facilitates allocating resources. The auctioneer communicates with federates and receives bids for buying and selling resources, solves combinatorial problems, and proposes prices to federates. Multiple auction-based mechanisms are formulated and assessed using collective performance metrics in a networked federation. The auction-based algorithms include four reverse-bid and double-sided auctions: (1) first-price auction, (2) sequential non-linear pricing auction, (3) min–max closed-form pricing auction, and (4) balanced and maximizing closed-form pricing auction. For results, we assess algorithms for economic and computational efficiency using extensive simulation runs in hundreds of network topologies and initial conditions. The metrics introduced for our numerical validation include normalized bids and prices, collective values, and convergence rates.

This paper introduces a mechanism for pricing and exchanging resources in federated networks of task-processing elements. An operational model is developed to allocate processing, storage and communication resources to computational demands. This model finds an efficient and stable solution to combinatorial routing and allocating resources among networked elements with technical constraints. Using mixed-integer linear programming (MILP) formulation, we find optimal solution to processing tasks, allocating links, storing and delivering data to destination. A trusted auctioneer uses a mechanism to allocate resources to computational tasks and suggests prices for exchanging resources across a federation using minimum number of MILP solutions to a network topology. The proposed mechanism maximizes the collective value for a federation and ensures an expected value for each federate and minimizes the computational cost associated with the operational runs. The auctioneer doesn’t have access to utility functions and private information on resources a priori while assumes a federation with self-centric and rational participants. An application of federated satellite systems is developed with endogenous components such as adaptive bidding and opportunity cost of using resources. Numerical results show that the proposed mechanism improves the collective and expected values in a federation with strategic federates.

Systems-of-systems engineering deals with a special class of engineered systems that lack the central control common in traditional systems engineering problems. This paper introduces the stag hunt game as an analogy for the fundamental collective decision-making challenges in systems-of-systems engineering. The stag hunt models a dilemma between two viable alternatives: an independent strategy that minimizes risk and a collaborative strategy that maximizes payoff. Results of equilibrium selection theory provide insights to ensure collaboration in systems-of-systems including maximizing upside potential, minimizing downside risk, and mitigating systemic risk sources such as cost overruns.

This paper performs an observational human subjects study to investigate how design teams use an information system to exchange, store, and synthesize information in an engineering design task. Framed through the lens of decision-based design, a surrogate design task models an aircraft design problem with 12 design parameters across four roles and six system-level functional requirements. A virtual design studio provides a browser-based interface for four participants in a 30-min design session. Data collected across 10 design sessions provide process factors about communication patterns and outcome factors about the resulting design. Correlation analysis shows a positive relationship between design iteration and outcome performance but a negative relationship between chat messages and outcome performance. Discussion explains how advances in information exchange, storage, and synthesis can support future design activities.

This paper evaluates perception of complexity in a novel explanatory model that relates product performance and engineering effort. Complexity is an intermediate factor with two facets: it enables desired product performance but also requires effort to achieve. Three causal mechanisms explain how exponential growth bias, excess complexity, and differential perception lead to effort overruns. Secondary data from a human subject experiment validates the existence of perception of complexity as a context-dependent factor that influences required design effort. A two-level mixed effects regression model quantifies differences in perception among 40 design groups. Results summarize how perception of complexity may contribute to effort overruns and outline future work to further validate the explanatory model and causal mechanisms.

Achieving new observing strategies at global and local scales must overcome engineering challenges related to decentralized control of mission elements and their models. This paper introduces concepts of co-simulation and service-oriented architectures to orchestrate individual simulation components to evaluate new mission architectures. A prototype software platform identifies essential simulation services to model the environment, mission elements, mission operations, and visualization. An example application case evaluates the detection latency for wildfire events for existing mission elements and a proposed constellation of small satellites.

The engineering of complex systems, such as aircraft and spacecraft, involves large number of individuals within multiple organizations spanning multiple years. Since it is challenging to perform empirical studies directly on real organizations at scale, some researchers in systems engineering and design have begun relying on abstracted model worlds that aim to be representative of the reference socio-technical system, but only preserve some aspects of it. However, there is a lack of corresponding knowledge on how to design representative model worlds for socio-technical research. Our objective is to create such knowledge through a reflective case study of the development of a model world. This “inner” study examines how two factors influence interdisciplinary communication during a concurrent design process. The reference real world system is a mission design laboratory (MDL) at NASA, and the model world is a simplified engine design problem in an undergraduate classroom environment. Our analysis focuses on the thought process followed, the key model world design decisions made, and a critical assessment of the extent to which communication phenomena in the model world (engine experiment) are representative of the real world (NASA’s MDL). We find that the engine experiment preserves some but not all of the communication patterns of interest, and we present case-specific lessons learned for achieving and increasing representativeness in this type of study. More generally, we find that representativeness depends not on matching subjects, tasks, and context separately, but rather on the behavior that emerges from the interplay of these three dimensions.

This paper draws on perspectives from co-design as an integrative and collaborative design activity and co-simulation as a supporting information system to advance engineering design methods for problems of societal significance. Design and implementation of the Sustainable Infrastructure Planning Game provides a prototypical co-design artifact that leverages the High Level Architecture co-simulation standard. Three role players create a strategic infrastructure plan for agriculture, water, and energy sectors to meet sustainability objectives for a growing and urbaninzing population in a fictional desert nation. An observational study conducts 15 co-design sessions to understand underlying dynamics between actors and how co-simulation capabilities influence design outcomes. Results characterize the dependencies and conflicts between player roles based on technical exchange of resource flows, identifying tension between agriculture and water roles based on water demands for irrigation. Analysis shows a correlation between data exchange, facilitated by synchronous co-simulation, and highly-ranked achievement of joint sustainability outcomes. Conclusions reflect on the opportunities and challenges presented by co-simulation in co-design settings to address engineering systems problems., 44 pages, 11 figures

Software crowdsourcing platforms allow for wide task accessibility and self-selection, which require participants to interact with a wide range of task options. This increased accessibility enables crowd workers to freely choose tasks based on their skills, experience and interests. However, the inconsistencies in crowd workers’ comprehension and interpretation of the designs of different tasks and the platform interaction strategies may introduce task uncertainty into the selection process. This may result in low performance, which can diminish the quality of the crowdsourcing platform. Previous studies show that the quality of the outcome of these systems depends on different design parameters in both social and technical contexts. Therefore, through the lens of Socio-Technical Systems, our experimental study quantifies and compares 30 participants’ behavior and performance throughout their interaction and selection of different software tasks via an online-based tool named “SoftCrowd,” using different design strategies and task features. Results showed a significant relationship between task submission rate and platform design, including interaction strategies, task ambiguity and task instruction design. These findings suggest that our proposed design factors may have unanticipated effects on the quality of crowdsourcing, calling for more studies of crowdsourcing design to inform better strategies for various aspects of platform design.

The experiment studies the effect of technical and social sources of complexity on effort required to complete abstracted design tasks. Parameter design tasks define a set of input design parameters and functional requirements modeled with a linear coupling matrix. Selecting design variables to meet all functional requirements within error limits completes a task. Technical complexity arises from the number and degree of coupling between design parameters. Social complexity arises from the number of designers involved in a task. The experiment includes 10 sessions with between 19 and 24 rounds of randomly generated parameter design tasks each having between two and six design variables and one, two, or three designers. Designers completed individual tasks in parallel during rounds. This article contains raw and post-processed data from 374 completed tasks ranging in effort from a few seconds for simple tasks to more than 15 min for complex ones.

Design methods for federated systems must consider local incentives and interactive effects among independent decision-makers. This paper extends value-centric design methodology to multi-actor cases by using game-theoretic principles. Federated systems are represented as a Stag Hunt game where players choose between independent (noncooperative) and federated (cooperative) strategies. Risk arises from the possibility of withdrawn cooperation and can be quantitatively assessed for particular design alternatives with subjective estimates of the probability for cooperation and objective measures such as the weighted average log measure of risk. The value of cooperation can be bounded below by designing for the independent strategy and above by designing for a centralized strategy controlled by a single authority. An application case considers a stylized system value model of a distributed satellite system with two players and symmetric design decisions. Results demonstrate lower and upper bounds to the value of a federated strategy with opportunistic, fixed-cost communication services. Quantitative risk analysis shows the value-maximizing federated design under mutual cooperation carries risk which can be mitigated by more conservative design alternatives with only minor loss of value.

Infrastructure planners need new methods to exchange technical data in the pursuit of long-term and cross-sector objectives including sustainability. This paper demonstrates a method for infrastructure system simulation interoperability by applying the high-level architecture (HLA) to the infrastructure system of systems (ISoS) modeling framework. The ISoS considers time-aggregated simulations with iterative data exchange periods to resolve cyclic dependencies. Applying the HLA defines object models, operational agreements, federate implementations, and physical infrastructure required for a federated simulation. An example demonstrates the method on a scenario with 18 infrastructure elements across water, electricity, petroleum, and social sectors as individual federates. The cost of interoperability arises from network latency, runtime infrastructure (RTI) overhead, and additional development effort. Results across several RTIs show that a distributed simulation requires 10–100 times longer executions than noninteroperable configurations. Analysis of source code shows that the HLA contributes about 1500 (56%) more software lines of code to implement federation object models and agreements. The value of interoperability arises from new capabilities provided by the HLA: physical distribution and independent control of constituent models. Conclusions describe a role for the HLA in model-based concept exploration during collaborative and interorganizational design activities with live human participation similar to its use for wargames.

Recent interest in applications of games and gaming methods has stimulated discussion of their use in engineering systems research. Simulation games or gaming simulations are interactive environmen ...

Earth observing systems are undergoing an architectural transformation to perform novel scientific campaigns by dynamically composing assets from government and commercial partners. Correspondingly, campaign-level engineering methods and tools must accommodate greater degrees of decentralized control and independence. This paper reviews advances provided by semantic web technology and distributed simulation to highlight some of the challenges in modeling Earth observing systems of systems. A campaign simulation framework organizes the contextual, structural, and behavioral features necessary to model Earth observing systems from a system of systems perspective. Finally, a multi-actor value framework considers interactive negotiation of non-commensurate preferences by participating entities.

Engineered system architectures leveraging collaboration among multiple actors across organizational boundaries are envisioned to be more flexible, robust, or efficient than independent alternatives but also carry significant downside risks from new interdependencies added between constituents. This paper transitions the concept of risk dominance from equilibrium selection in game theory to engineering design as a strategic measure of collective stability for system of systems. A proposed method characterizes system design as a bi-level problem with two or more asymmetric decision-makers. A measure of risk dominance assesses strategic dynamics with respect to the stability of joint or collaborative architectures relative to independent alternatives using a novel linearization technique to approximate linear incentives among actors. An illustrative example case for an asymmetric three-player design scenario shows how strategic risk dominance can identify and mitigate architectures with unstable risk-reward dynamics.

Design of complex systems requires collaborative teams to overcome limitations of individuals; however, teamwork contributes new sources of complexity related to information exchange among members. This paper formulates a human subjects experiment to quantify the relative contribution of technical and social sources of complexity to design effort using a surrogate task based on a parameter design problem. Ten groups of 3 subjects each perform 42 design tasks with variable problem size and coupling (technical complexity) and team size (social complexity) to measure completion time (design effort). Results of a two-level regression model replicate past work to show completion time grows geometrically with problem size for highly coupled tasks. New findings show the effect of team size is independent from problem size for both coupled and uncoupled tasks considered in this study. Collaboration contributes a large fraction of total effort, and it increases with team size: about 50–60 % of time and 70–80 % of cost for pairs and 60–80 % of time and 90 % of cost for triads. Conclusions identify a role for improved design methods and tools to anticipate and overcome the high cost of collaboration., American Society for Engineering Education. National Defense Science and Engineering Graduate Fellowship

Engineering design games model decision-making activities by incorporating human participants in an entertaining platform. This article distinguishes between design decisions at operational and strategic timescales as important features of engineering design games. Operational decisions consider static and short-term dynamic decisions to establish a player’s situation awareness and initial entertainment. Strategic decisions consider longer-term dynamic decisions subject to large uncertainties to retain player engagement. However, constraints on cognitive load limit the ability to simultaneously address both lower-level operational design decisions and higher-level strategic decisions such as collaboration or sustainability. Partial automation can be introduced to reduce cognitive load for operational decisions and focus additional effort on strategic decisions. To illustrate tradeoffs between operational and strategic decisions, this paper discusses example cases for two existing games: Orbital Federates and EcoRacer. Discussion highlights the role of automation and entertainment in engaging human participants in engineering design games and makes recommendations for design of future engineering design games.

Cyber-Physical Systems (CPS) integrate computation, networking and physical processes to produce products that are autonomous, intelligent, connected and collaborative. Resulting Cyber-Physical Systems of Systems (CPSoS) have unprecedented capabilities but also unprecedented corresponding technological complexity. This paper aims to improve understanding, awareness and methods to deal with the increasing complexity by calling for the establishment of new foundations, knowledge and methodologies. We describe causes and effects of complexity, both in general and specific to CPS, consider the evolution of complexity, and identify limitations of current methodologies and organizations for dealing with future CPS. The lack of a systematic treatment of uncertain complex environments and “composability”, i.e., to integrate components of a CPS without negative side effects, represent overarching limitations of existing methodologies. Dealing with future CPSoS requires: (i) increased awareness of complexity, its impact and best practices for how to deal with it, (ii) research to establish new knowledge, methods and tools for CPS engineering, and (iii) research into organizational approaches and processes to adopt new methodologies and permit efficient collaboration within and across large teams of humans supported by increasingly automated computer aided engineering systems.

Design methods for federated systems must consider local incentives and interactive effects among independent decision-makers. This paper extends value-centric design methodology (VCDM) to multi-actor cases using game theoretic principles. Federated systems can be represented as a Stag Hunt game where players choose between risk-dominant (non-cooperative) and payoff-dominant (cooperative) strategies. An independent strategy is a lower bound to federated value and a centralized strategy controlled by a federation authority is an upper bound under special cases. An application case considers a stylized system value model (SVM) of a federated satellite system (FSS) with two players and a tradespace of 530 symmetric design decisions. A federated concept with opportunistic, fixed-cost communication services demonstrates the effect of lower and upper bounds on system value. Risk in federated systems arises from misaligned strategies between players and can be quantitatively assessed with a subjective estimate of cooperation.