PhD Defense by A. Ehsanfar

Time: Thursday OCT 4th, 2018

Location:  CCSE lab, Babbio, Stevens Institute of Technology.

Title: Allocative Mechanisms And Information Exchange In Task Processing And Interactive Networks

Abstract: This thesis investigates analysis techniques and mechanisms for exchanging and valuating resources and information in a task processing network of elements (TNE) and interactive social networks. For a federated TNE, a trusted auctioneer uses a mechanism to allocate resources to computational tasks and suggests prices for exchanging resources across a federation. An operational mechanism allocates processing, storage and communication resources to computational demands. This model finds an efficient solution to combinatorial routing with technical and financial constraints. Using mixed-integer linear programming (MILP) formulation, the operational model finds an optimal solution to processing tasks, allocating links, storing and delivering data to destinations. The auctioneer assumes a federation of self-centric and rational strategic participants/bidders/federates and simulation results show improvement in collective and expected values for federates. For mechanism design in a federated TNE, this research investigates an auctioneer equipped with auction-based algorithms to drive behavior of decentralized components towards higher collective-efficient metrics. This work formulates five auction-based algorithms for exchanging resources and combinatorial routing in a federated network: 1) linear program with binary search for prices, 2) first-price reverse-bid double auction, 3) non-linear searching for prices, 4) online algorithm with closed-form solution for prices, and 5) virtual pricing in a multi-source and multi-hop routing case. Metrics for numerical validation include normalized bids and prices, collective values, and pricing convergence rate of algorithms. Extensive simulation runs using hundreds of topologies with different configurations of elements and federates show better computational performance and higher economic efficiency for the online algorithm with a closed-form and variation-reducing solution for prices. Finally, this thesis investigates incentivizing mechanisms for information exchange in interactive social networks by clustering and modeling viral topics on social networks as a collective result of micro-level behavior of interactive components (participants). Analysis investigates the nature of influence and interactions on social networks. A data-driven approach observes endogenous and exogenous influences on emergence of linguistic topics and content on Twitter based on metrics such as popularity, burstiness, relevance score, consolidation, and hierarchal and temporal similarities. Conclusions outline future work to capture behavioral metrics of users on evolution of content and discourse in the interactive social network.

Published in Data in Brief

A new open access data article appears in Data in Brief to provide open access to a data set collected from a human designer experiment:

Data on multi-actor parameter design tasks by engineering students with variable problem size, coupling, and team size

Paul T. Grogan

Abstract: 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.

Published at ASME IDETC 2018

Two papers were presented this week at the ASME International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC/CIE) in Quebec City, Canada.

Toward a Model-based Experimental Approach to Assessing Collective Systems Design Processes

A. Valencia Romero and P.T. Grogan in Design Theory Methodology (DTM)

Abstract: This work presents a conceptual model of collective decision-making processes in engineering systems design to understand the tradeoffs, risks, and dynamics between autonomous but interacting design actors. The proposed approach combines value-driven design, game theory, and simulation experimentation to study how technical and social factors of a design decision-making process facilitate or inhibit collective action. The collective systems design model considers two levels of decision-making: 1) lower-level design value exploration; and 2) upper-level design strategy selection. At the first level, the actors concurrently explore two strategy-specific value spaces with coupled design decision variables. Each collective decision is mapped to an individual scalar measure of preference (design value) that each actor seeks to maximize. At the second level, each of the actor’s design values from the two lower-level design exploration tasks is assigned to one diagonal entry of a normal-form game, with off-diagonal elements calculated in function of the “sucker’s” and “temptation-to-defect” payoffs in a classical strategy game scenario. The model helps generate synthetic design problems with specific strategy dynamics between autonomous actors. Results from a preliminary multi-agent simulation study assess the validity of proposed design spaces and generate hypotheses for subsequent studies using human subjects.

Operational and Strategic Decisions in Engineering Design Games

P.T. Grogan and A.E. Bayrak in Design Automation Conference (DAC)

Abstract: 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.

Panel for Treatment: A Plan for Rain

7:00pm on Thursday, June 7, 2018, RSVP.

Paul Grogan will participate in a panel discussion at Nicholas O’Brien’s exhibition Treatment: A Plan for Rain at the Knockdown Center in Maspeth, NY. From the event page:

Topics to be discussed include biodiversity, urban planning, and maintenance, and participants will aim to unpack and sort through the interweaving disciplines that influence and affect the strategies and implementation of green infrastructure in the city and beyond.

2018 Doctoral Research Symposium

Members of the CoDe Lab participated in the Doctoral Research Symposium at Stevens Institute of Technology from May 21-22, 2018. Pictured outside the Stevens Gatehouse, left-to-right below: Abbas (Ehsan) Ehsanfar, Henry Lee, Stephanie Chiesi, Paul Grogan, Brian Gardner, Ambrosio Valencia-Romero.

Presentation titles:

  1. Brian Gardner: “Evaluation of Robustness of Space Exploration Logistics Network Subject to Uncertainty”
  2. Abbas Ehsanfar: “Mechanism Design in Federated Networks”
  3. Ambrosio Valencia-Romero: “Toward a Model-based Experimental Approach to Assessing Collective Engineering Systems Design Processes”
  4. Stephanie Chiesi: “Transformation to Digital Engineering: Exploring the Systems Engineering Challenges in Aerospace and Defense”

Published in Systems Engineering

A new article appears in Systems Engineering Early View today as a contribution to a special issue from the CESUN 2016 symposium:

Gaming Methods in Engineering Systems Research

Paul T. Grogan and Sebastiaan A. Meijer

Abstract: 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 environments which simultaneously model a technical system through simulation and a social system with role-play participants. Their boundary-spanning nature aligns with challenges in engineering systems to consider both technical and social factors in design. This paper outlines a class of gaming methods for research in engineering systems. Key contributions synthesize diverse bodies of literature to classify gaming applications as generating generalizable and contextual knowledge to benefit participants and principals, identify intellectual foundations in related social sciences, and describe the dual purpose of games as a research method for analytical or design science objectives. Conclusions highlight opportunities and challenges for gaming research methods to accommodate social science research in design-centric activities.

 

Space Exploration Logistics Analysis using Network Simulation

Future human space exploration to distant locations including the Moon, Mars, and beyond carries many logistical challenges. Imagine planning a year-long road trip for a family of four. All consumables, food, water, and oxygen, must be a part of the logistics plan. However, there are also no gas or service stations along the way. No garbage or waste disposal either. Oh, and the environment outside is a freezing vacuum bombarded with radiation. Some of the key questions to answer include: How much cargo space is needed and how much is available for non-essential items including your favorite science experiment? Are there intermediate locations where cargo can be stored and retrieved? What is the right tradeoff between bringing all possible spares versus having a chance to break down on the way? How much investment should be made in resource recycling to reduce the overall burden?

From this perspective, the Apollo missions were similar to a two week backpacking trip and ISS expeditions are similar to visiting a permanently-staffed remote wilderness outpost. Both carry significant logistical problems and issues; however, they are substantially less complex than future human space exploration missions.

Network-based simulation models can help plan logistics for space exploration missions. SpaceNet is a discrete event network simulation which models the flow of people, vehicles, and resources between planetary surfaces and stable orbits. Each of these nodes are linked by a series of edges which represent valid trajectories – launches, landings, and in-space maneuvers. During a simulation, vehicles and resources are generated, moved, and consumed to satisfy needs of human crew members. Architects can specify a baseline plan (mission concept) and, through simulation, evaluate a series of performance metrics to determine how good of a plan it is relative to others.

SpaceNet leverages two key contributions to understanding and modeling space logistics. First, it builds on a ten main classes of supply which help to distinguish resources from one another. These include:

  1. Propellants and Fuels: used for propulsion
  2. Crew Provisions: food, water, oxygen, and other essentials
  3. Crew Operations: health, sanitary, and communications equipment
  4. Maintenance and Upkeep: tools for repair and spare parts
  5. Stowage and Restraint: packaging materials and containers
  6. Exploration and Research: tools for exploration and scientific experiments
  7. Waste and Disposal: garbage, human waste, and processing equipment
  8. Habitation and Infrastructure: vehicles with inhabitable environments for crew
  9. Transportation and Carriers: vehicles capable of transporting items
  10. Miscellaneous: anything else!

In addition to the 10 main classes of supply, there are numerous subclasses to help refine definitions to finer and finer levels of detail. For example, there are several types of propellants and fuels which are completely incompatible with each other (liquid oxygen, kerosene, hypergolic, solid fuels). Classes of supply help to identify what resources are compatible with which demands and enable advanced logistics strategies such as in-situ resource production and caching at an intermediate depot.

Second, SpaceNet identifies a core set of seven mission events which occur in the exploration network. Events are the atomic mission units which generate state transitions simulation model. Create, Reconfigure, Move, or Destroy elements events operate on vehicles, crew, or other persistent objects. Generate, Move, or Consume resources events operate on ephemeral substances ultimately consumed by demands.

More complex processes such as launches or explorations compose these seven core events in many new ways. For example, a launch process consumes resources (propellant), destroys elements (expended stages), and finally moves elements to the intended orbit. Similarly, an exploration process consumes resources (crew metabolism), reconfigures elements (crew don EVA suits), moves elements (crew exit the habitat), generates resources (crew collect surface samples), and moves resources (crew store samples in return vehicle).

Simulation alone cannot answer all of the questions about future space exploration. Humans are still required to code all of the important behaviors in a simulation model and come up with the various mission concepts to evaluate. Future research may improve the ability of simulation models to automatically adapt mission concepts and improve performance metrics. Recent work by other researchers including Dr. Takuto Ishimatsu and Dr. Koki Ho contribute to these goals; however, more work is still necessary to help plan for future space exploration missions.

For more information, please see:

Grogan Receives Roos Prize

Yesterday Dr. Grogan accepted the 2014 Daniel and Eva Roos Engineering Systems Dissertation Prize at a ceremony hosted at the Institute for Data, Systems, and Society (IDSS) at Massachusetts Institute of Technology. The award recognizes contributions of original and generalizable scholarship in his dissertation titled “Interoperable Simulation Gaming for Strategic Infrastructure Systems Design.”

Rebecca Saari, Paul Grogan, Daniel Roos, Eva Roos, Daniel Livengood, Vivek Sakhrani (courtesy Beth Milnes)

Dr. Grogan joined peers Dr. Daniel Livengood (2012), Prof. Rebecca Saari (2015), and Dr. Vivek Sakhrani (2016). Other awardees unable to attend include Dr. Nidhi Santen (2013) and Dr. Amanda Giang (2017).

An electronic copy of Dr. Grogan’s dissertation is available via DSpace.

Doctoral Student Position Available

The Collective Design Lab has a research assistantship (RA) available for a doctoral student in Systems or Software Engineering to start in January 2018. Candidates should have excellent skills in abstraction and modeling and interest in topics of model-centric engineering, machine learning, and space systems.

Please contact Dr. Grogan with requests for additional information.