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Michael Gabbay

Senior Principal Physicist






Dr. Gabbay's current research involves the development of mathematical models and computational simulations of network dynamics, focusing on social and political systems. He has also conducted research in the areas of nonequilibrium pattern formation, coupled oscillator dynamics, sensor development, and data analysis algorithms. His work has appeared in physics, engineering, biology, and political science publications. Dr. Gabbay received a B.S in physics from Cornell University and a Ph.D. in physics from the University of Chicago with a specialization in nonlinear dynamics.


2000-present and while at APL-UW

Social network analysis in the study of terrorism and insurgency: From organization to politics

Zech, S.T., and M. Gabbay, "Social network analysis in the study of terrorism and insurgency: From organization to politics," Int. Stud. Rev., 18, 214-243, doi:10.1093/isr/viv011, 2016.

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1 Jun 2016

Research using social network analysis to study terrorism and insurgency has increased dramatically following the 9/11 attacks against the United States. This research emphasizes the importance of relational analysis and provides a variety of concepts, theories, and analytical tools to better understand questions related to militant group behavior and outcomes of terrorism and insurgent violence. This paper defines key network concepts, identifies important network metrics, and reviews theoretical and empirical research on network analysis and militant groups. We find that the main focus of existing research is on organizational analysis and its implications for militant group operational processes and performance. Few studies investigate how differences in network structure lead to divergent outcomes with respect to political processes such as militant group infighting, their strategic use of violence, or how politically salient variables affect the evolution of militant cooperative networks. Consequently, we propose a research agenda aimed at using network analysis to investigate the political interactions of militant groups within a single conflict and provide illustrations on how to pursue this agenda. We believe that such research will be of particular value in advancing the understanding of fragmented civil wars and insurgencies consisting of multiple, independent militant groups.

Data processing for applications of dynamics-based models to forecasting

Gabbay, M., "Data processing for applications of dynamics-based models to forecasting," in Sociocultural Behavior Sensemaking: State of the Art in Understanding the Operational Environment, J.E. Egeth, G.L. Klein, and D. Schmorrow, eds., 245-268 (McLean, VA: The MITRE Corporation, 2015).

1 Jan 2015

Majority rule in nonlinear opinion dynamics

Gabbay, M., and A.K. Das, "Majority rule in nonlinear opinion dynamics," in International Conference on Theory and Application in Nonlinear Dynamics (ICAND 2012), edited by V. In, A. Palacios, and P. Longhini, 167-179, doi:10.1007/978-3-319-02925-2_15 (Switzerland: Springer International, 2014).

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1 Jan 2014

Using a nonlinear model of opinion dynamics on networks, we show the existence of asymmetric majority rule solutions for symmetric initial opinion distributions and symmetric network structure. We show that this occurs in triads as the result of a pitchfork bifurcation and arises in both chain and complete topologies with symmetric as well as asymmetric coupling. Analytical approximations for bifurcation boundaries are derived which closely match numerically-obtained boundaries. Bifurcation-induced symmetry breaking represents a novel mechanism for generating majority rule outcomes without built-in structural or dynamical asymmetries; however, the policy outcome is fundamentally unpredictable.

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Terrorism and small groups: An analytical framework for group disruption

Reedy, J., J. Gastil, and M. Gabbay, "Terrorism and small groups: An analytical framework for group disruption," Small Group Res., 44, 599-626, doi:10.1177/1046496413501892, 2013.

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1 Dec 2013

Terrorism scholarship has revealed the importance of small groups—both cells and leadership groups—in the proliferation of violence, yet this field remains only loosely connected to small group theory and research. There exists no systematic consideration of the role that group dynamics play in the disruption of terrorist activities. This article proposes an analytical framework for terrorist group disruption that shows how the goals and methods of counterterrorist intervention intersect with small group behavior. We use this framework to theorize how three intervention types—repression, manipulation, and persuasion—interact with group variables and processes, such as communication networks, social identities, group cohesion, and intragroup conflict. Seven theoretical propositions demonstrate how the framework can show how the direct and indirect effects of group behavior can augment or undermine counterterrorist strategies.

Modeling decision-making outcomes in political elite networks

Gabbay, M., "Modeling decision-making outcomes in political elite networks," Complex Sciences, 126, 95-110, 2013. [Proc., 2nd International Conference, COMPLEX, 5-7 December 2012, Santa Fe, NM, K. Glass, et al., eds., 95-110 (Springer International Publishing, New York, 2013).]

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1 Jun 2013

A methodology for modeling group decision making by political elites is described and its application to real-world contexts is illustrated for the case of Afghanistan. The methodology relies on the judgments of multiple experts as input and can improve analysis of political decision making by elucidating the factional structure of the group of elites and simulating their interaction in a policy debate. This simulation is performed using a model of small group decision making which integrates actor policy preferences and their inter-relationship network within a nonlinear dynamical systems theory framework. In addition to the basic nonlinear model, various components required to implement the methodology are described such as the analyst survey, structural analysis, and simulation. Implementation and analysis results are discussed for both the government and insurgent sides of the current conflict in Afghanistan.

The Rabbani assassination: Taliban strategy to weaken national unity?

Gabbay, M., "The Rabbani assassination: Taliban strategy to weaken national unity?" CTC Sentinel, 5, 10-14, 2012.

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22 Mar 2012

This article first considers the Rabbani assassination and finds it unlikely that it was conducted by "spoilers" distinct from the Taliban central leadership. The killing of the head of Afghan reconciliation efforts with insurgents is on its face a Taliban rejection of negotiations with the Afghan government, the only party with whom a meaningful peace settlement can be made. Analysis of his position within the network of government elites, however, suggests that the Taliban's overriding motive in targeting Rabbani was not to punctuate a rejection of peace talks, but rather to exacerbate ethnic cleavages within the Afghan government, thereby weakening its cohesion and isolating President Hamid Karzai. Chipping away at Afghan national unity is a companion political strategy in service of the military objective of weakening the ANSF who, given the U.S. drawdown, will form the primary obstacle to Taliban control of either the Pashtun belt in the south and east or the country as a whole.

Multi-task regularization of generative similarity models

Cazzanti, L., S. Feldman, M.R. Gupta, and M. Gabbay, "Multi-task regularization of generative similarity models," in Proc., First International Workshop on Similarity-based Pattern Recognition, Venice, Italy, 28-30 September, M. Pelillo and E.R. Hancock, eds. (Berlin, Springer, 2011).

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24 Sep 2011

We investigate a multi-task approach to similarity discriminant analysis, where we propose treating the estimation of the different class-conditional distributions of the pairwise similarities as multiple tasks. We show that regularizing these estimates together using a least-squares regularization weighted by a task-relatedness matrix can reduce the resulting maximum a posteriori classification errors. Results are given for benchmark data sets spanning a range of applications. In addition, we present a new application of similarity-based learning to analyzing the rhetoric of multiple insurgent groups in Iraq. We show how to produce the necessary task relatedness information from standard given training data, as well as how to derive task-relatedness information if given side information about the class relatedness.

A quantitative analysis of insurgent frames, claims, and networks in Iraq

Gabbay, M., and A. Thirkill-Mackelprang, "A quantitative analysis of insurgent frames, claims, and networks in Iraq," in Proc, Annual Meeting of the American Political Science Association, Seattle, 1-4 September 2011.

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1 Sep 2011

Although the fundamental importance of the political dimension of insurgencies is widely accepted, there has been little effort to develop a dedicated theory of what is the most central political observable of insurgents - their rhetoric. We propose a theoretical framework that addresses three key features of insurgent rhetoric: (1) ideologies as represented by "conflict frames," which consist of the in-groups and out-groups in insurgent discourse; (2) operational claims of attacks; and (3) publicly declared tactical cooperation with other insurgent groups. Quantitative representations of these features are constructed and empirically implemented on the rhetoric of Iraqi insurgent groups from 2003-2009. Our framework considers a group's conflict frame as a form of master organizing logic by which the group seeks the conflict to be understood; a group's operational claims are a way of establishing its action-oriented character and serve to reinforce its conflict frame. Accordingly, we expect that group conflict frames should be broadly consistent with their targeting portfolios - that is, the types of target classes which they claim to attack. This hypothesis is quantitatively supported by significant correlations between conflict frame and targeting portfolio variables. Additionally, in situations of intense factional competition, the base of active insurgency supporters is a prime audience for insurgent rhetoric, and so we also contend that a group's conflict frame should reflect the social identities of its desired constituency among the active base. This hypothesis is supported by correlation of group conflict frames with structure in the network of declared joint operations between groups. Our research demonstrates the ability to meaningfully quantify insurgent rhetoric and the importance of rhetoric as a tool for revealing insight into insurgent factional structure and dynamics.

You are who you kill: Insurgent claims, frames, and identities in Iraq

Gabbay, M., and A. Thirkill-Mackelprang, "You are who you kill: Insurgent claims, frames, and identities in Iraq," Proc., 52nd Annual Convention of the International Studies Association, Montreal, 16-19 March 2011, 40 pp.

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16 Mar 2011

Insurgent rhetoric is often treated dismissively as propaganda. This paper assumes an alternative perspective in which insurgent rhetoric is considered as sophisticated political rhetoric, capable of revealing meaningful insight into the internal structure of an insurgency especially under conditions of intense factional competition. Using a quantitative approach, we demonstrate that this is indeed the case using rhetoric of Iraqi Sunni insurgent groups. Our focus is on insurgent operational claims and, in particular, the types of target classes that insurgents claim to attack. We contend that variations in the claimed target classes should reflect differences in group composition among the base of active insurgency supporters. A theoretical framework is set forth in which insurgent operational claims and identity rhetoric are related to concepts from Aristotelian rhetoric theory, modern social identity theory, and framing theory. Several hypotheses following from this framework are proposed. We construct a quantitative "targeting policy" variable which gauges the perceived legitimacy of the portfolio of target classes claimed by a group. Targeting policy differences are seen to correspond with ideological differences. We also construct networks from insurgent rhetoric, in particular, claims of joint operations and joint communiques, indicative of insurgent group relationships at the foot soldier and leadership levels respectively. Correlations between targeting policy and the joint operations network structure support our argument that targeting claims are an indicator of social identities among a group's active support constituencies.

Insurgent operational claims and networks

M. Gabbay and A. Thirkill-Mackelprang, "Insurgent operational claims and networks," in Proc., Annual Meeting of the American Political Science Association, Washington, D.C., 2-5 September 2010.

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2 Sep 2010

Insurgent operational claims in Iraq are analyzed from the perspective that such claims can help illuminate the internal structure of an insurgency, especially in situations of intense factional competition between rival groups. Our primary focus is on the types of target classes that different insurgent groups claim to attack and claims of joint operations between insurgent groups. The former allows us to construct a targeting policy variable and the latter enables us to construct a network of relationships between insurgent groups, particularly at the foot soldier level. We contend that variations in the claimed target classes should reflect differences in group composition. Correlations between targeting policy and the joint operations network structure support this hypothesis.

We also present a model of insurgent cooperation with respect to joint operations. In addition to a homophily process driven by targeting policy proximity, the model posits both a horizontal interaction mechanism – that foot soldier units can initiate joint operations with units from other insurgent groups – and a hierarchical one in which the network linking the leaderships of insurgent groups also plays a role. Simulation results indicate a good ability to match the structure of the observed networks.

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center