CSAAW is pleased to present a new "featured student" every few weeks. If you know of candidates for future feature students, please contact the csaaw-organizers at umich.edu.
Senay Yitbarek, a doctoral student in the Department of Ecology and Evolutionary Biology. He works with Dr. John Vandermeer on questions related to spatial and theoretical ecology, with a particular emphasis on how competition shapes communities of interacting ant species.
Background: Understanding the very nature of biodiversity has been the central tenet in biology ever since the pioneering work by Darwin and Wallace. A primary goal of our work is to understand how self-organized ecological communities assemble in space. We seek to approach several enigmas of biodiverstiy by considering species ineractions in a meta-community framework. We model species interactions with a stochastic cellular automata model by extensively simulating species migrations from a species pool into a spatial lattice by imposing a competitive effect and response framework and relate their turnover (i.e., extinctions) to the covariance of the community matrix. We have shown that assembled communities are positioned along a continuum that ranges from spatial mosaic pathworks to intransitive networks that are critical in the maintenance of biodiversity.
Complex Systems Concepts: Spatial self organization; signals of self organization.
Modeling Tools: Stoachastic cellular automata modeling in Matlab; statistical analyses in R.
Our featured student is Abe Gong, a doctoral student in Public Policy and Political Science. He studies communication, participation, and information flow in political and organizational settings. His dissertation taps one of the richest sources of political data in all history—the political blogosphere—in order to understand timeless aspects of human interaction: attention, opinion, disagreement, persuasion, and participation. The dissertation committee includes Nancy Burns, Scott Page, Liz Gerber, Walter Mebane, and Nick Valentino. For more information, see Abe's webpage: www-personal.umich.edu/~agong.
Methods and tools: Abe's research uses a mix of computational and social science tools: survey research, content analysis, machine learning (especially natural language processing), and game theory. He does most of his analysis using python and R, and most of his web development in django, jquery and knockout.
Complex Systems concepts: information theory, aggregation and emergence, complex social interactions, Big Data.
Nguyen Nguyen is a Ph.D candidate in the Mechanical Engineering Department. His research focuses on self-assembly behavior of interacting self-propelled particles. While his primary interest lies in colloidal particles, which size in sub-micron scales, part of his research investigates the self-assembly of point particles. He is particularly interested in emergent ordered structures that are maintained far away from equilibria, how they form, and how one would control the self-assembling processes. This research has potential applications in areas such as new materials and devices and self-reconfigurable swarms of unmanned vehicles. His dissertation committee includes Prof. Sharon Glotzer, Prof. Michael Solomon, Prof. Ronald Larson and Prof. Donald Siegel..
Methods and tools: The research is conducted by using Molecular Dynamics simulation, which is implemented in the Graphics Processing Unit or GPU accelerated package HOOMD Blue (http://codeblue.umich.edu/hoomd-blue/). Statistical mechanics concepts and methods are utilized extensively to analyze the system. Most analysis codes are developed using C++, Bash and Python.
Complex Systems concepts: Self-assembly, emergence, collective behavior, pattern formation, swarming, phase transition
Our featured student is Seungjun Ahn, a Ph.D. candidate in the Civil and Environmental Engineering Department. His research focuses on modeling organizational behavior of construction workers and the impact of norms on the workers' behavior and predicting the system-level effectiveness of administration of construction projects. Currently, his work is concentrated on the absenteeism behavior of construction workers. Within the current research scope, particular research questions are 1) how and to what extent do absence cultures influence individual absence behavior (culture exertion); 2) how and with what information do employees align their absence behaviors with absence cultures (cross-level link); and 3) how do absence cultures arise from different individual behaviors (culture formation). His dissertation committee includes Prof. SangHyun Lee (Advisor, CEE), Prof. Vineet Kamat (CEE), Prof. Frank Yates (PSYCH), and Prof. Scott Page (POLSCI and CSCS).
Methods and tools: Complex systems modeling methodologies, such as System Dynamics (SD) and Agent-Based Modeling (ABM), are utilized. He primarily uses Vensim as a System Dynamics tool and Java for ABM.
Complex Systems concepts: Organizational Behavior, Emergence of Norms, Cultural Impact on Individuals, Sensemaking in Organizations, Agent-Based Modeling, System Dynamics