Spring 2006 Talk Series on

Networks and Complex Systems

Every Monday 6-7p, Wells Library LI001 ~ Optional Dinner at at Lennie's Afterwards

This talk series is open to all Indiana University faculty and students interested in network analysis, modeling, visualization and complex systems research.

A major intent is to cross-fertilize between research done in the social and behavioral sciences, research in 'hard core' sciences such as biology or physics, but also research on Internet technologies.

Links to people, projects, groups, students, courses and news related to complex systems and networks research at Indiana University are also available via the CSN web site.

Katy Börner <katy@indiana.edu> Associate Professor of Information Science, SLIS, IUB.

Time & Place
Every Monday 6:00-7:00pm in the Wells Library LI 001 (formerly Main Library), Indiana University, Bloomington. Right after the Cognitive Science Colloquium Series. There is an optional dinner afterwards 7-9p at Lennie's.

Students interested to attend the talks for credit need to register for L600 (1 credit) with Katy Börner. Proposal form is here. Grading will be based on the attendance of 8 talks (sign-up sheets will be provided) and a 4-5 page write-up that synergizes/aggregates major points made by a subset of the speakers to be submitted at the end of the semester.

Previous Semesters
Fall 2004
Spring 2005
Fall 2005

Evolving list of recommended readings. See also the Wikipedia entries on graph theory, small world networks, power law, and complex networks, and self organizing systems.

Related series
Cambridge Colloquium on Complexity and Social Networks organized by Davin Lazer at Harvard.

Faculty, Indiana University Bloomington

materials iconmaterials icon Network & Complex Systems Courses at IUB

Network & Complex Systems talks with Katy Börner, SLIS
Information Visualization by Katy Börner, SLIS
Web Mining by Filippo Menczer, Informatics
Mathematical Methods in Biology by James A. Glazier, Physics
Internet Services and Protocols by Minaxi Gupta, CS

1/16 M. L. King, Jr. Day

1/23 W. Bradford Paley, Digital Image Design Incorporated / Columbia University

materials icon Supporting Visual Analysis: Perceptual, Cognitive, and Semantic Techniques

Abstract: W. Bradford Paley has deployed work in seemingly diverse settings: the Museum of Modern Art, the New York Stock Exchange, NYU Bioinformatics, the Whitney; he has won equally diverse recognition: an ID Design Distinction award, Grand Prize in Tokyo's international arts festival, engineering tool awards for input devices, fellowship in the New York Foundation for the Arts. The same principles drive all of this work: If you engage the eye, you can engage the mind--as long as you "know the protocol," and keep the message consistent.

This talk has two parts. The first part will describe a knowledge acquisition pipeline: A designer/engineer's abstraction of visual, cognitive, and semantic "protocols" that engage seven distinct layers of the visual thinking processes. The second part introduces numerous examples of Mr. Paley's work informed by these protocols. Among them are the artwork TraceEncounters which is becoming a social network analysis tool for use by real researchers; the Whitney-commissioned CodeProfiles has been mistaken for a debugging tool; the Structualist text analysis tool TextArc was "mistaken for art" and won the Tokyo New Media Festival's grand prize.

1/30 Harold D. Green, Jr., Science of Networks in Communities (SONIC) Research Group, National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign

materials iconmaterials iconMapping Artistic, Cultural, and Network Assets in the Chicago Metropolitan Area: Context, Project Design, Implementation, and Initial Findings

Abstract: The Chicago metropolitan area has, for the past few years, become a key destination for Mexican transnationals, both temporary and permanent. Post-NAFTA Mexican immigrants have combined their cultural, artistic and network resources to create hybrid behavioral and cultural forms unlike those commonly used in America or Mexico. The use of these hybrid forms allows migrants to leverage their social and cultural resources to gain access to basic assistance, jobs, social support services, and other types of group-based or group-facilitated resources. This study was conducted in conjunction with the Field Museum in Chicago. It combined innovations in ethnographic research—such as the use of Atlas Ti and other ethnographic support tools—with new techniques for egocentric social network data collection that incorporate electronic data collection and one-touch network discovery capabilities, to delve more deeply into the realities of life for the Mexican immigrant community. In the process, aspects of the widely popular ‘network theory of migration’ are investigated in more detail than has been previously possible. In this talk, I present the motivations for the project, identify the factors that led to the synthesis of ethnography and social network analysis, explain the new approaches that the research team developed and, finally, present some initial findings from the project, calling attention to how those findings correspond to current thinking vis-à-vis ‘network theory of migration’ and to the current immigration policy environment.

2/6 Doug Gregor, SoI, IUB

materials iconmaterials icon Large-Scale Network Analysis with the Boost Graph Libraries

Abstract: In recent years, our ability to collect network data has increased far beyond our capabilities to analyze this data. With this deluge of data, the simple, direct implementations of network analyses and data structures no longer suffice, and we must turn to more advanced techniques such as graph compression and parallel computing. This talk will introduce the Boost Graph Libraries, a set of libraries for graph and network analysis developed by the Open Systems Lab at Indiana University. The Boost Graph Libraries provide a consistent set of interfaces across the entirety of the productivity--performance spectrum, from the rapid-prototyping and visualization capabilities of
BGL-Python, to the high-performance sequential BGL and cluster-capable Parallel BGL. This talk will explore the relative merits of each library, to determine which BGL may be right for your network analysis task, regardless of whether your network is measured in tens, thousands, millions, or billions.

2/13 Tamara Munzner, Department of Computer Science, University of British Columbia

materials iconmaterials icon Scalable Visual Comparison of Biological Trees and Sequences

Abstract: We present the TreeJuxtaposer and SequenceJuxtaposer visualization applications for comparing and browsing evolutionary trees and genomic sequences, respectively. These systems use the Focus+Context navigational metaphor of allowing users to fluidly stretch and shrink parts of the view, as if manipulating a rubber sheet with the borders tacked down. We introduce cognitive scalability to this approach by guaranteeing the visibility of landmarks at all times, so that users can stay oriented as they explore complex datasets. In our systems, landmarks can be regions of difference between datasets, or the results of a search, or user-chosen regions. This technique, which we call "accordion drawing", supports smooth realtime transitions between a big-picture overview and a drilled-down views that show details in context. Our new PRISAD infrastructure is highly scalable, allowing fluid realtime interaction with trees of several million nodes and multiple aligned sequences of up to 40 million total nucleotides.

2/20 Robert Goldstone, Department of Psychological and Brain Sciences, and Program in Cognitive Science, Indiana University

materials iconmaterials icon The Propagation of Innovations in a Social Network

Abstract: We have developed an internet-based experimental platform (for examples, see
http://groups.psych.indiana.edu) that allows groups of 2-200 people to interact with each other in real time on networked computers. I will describe experiments using this platform that explore how people attempt to solve simple problems while taking advantage of the developing solutions of other people in their social network. Over 15 rounds of problem solving, participants received feedback not only on the success of their own solutions to a simple search problem, but also on their neighbors¹ solutions and outcomes. Neighbors were determined by one of four network topologies: locally connected lattice, random, fully connected, and small-world (e.g. a lattice plus a few long-range connections). The results suggest that complete information is not always beneficial for a group, and that problem spaces requiring substantial exploration may benefit from networks with mostly locally connected individuals. We model the dissemination of innovations in these experiments using agents that probabilistically select choices guided by their own and their neighbors' explorations.

2/27 Larry Yaeger, School of Informatics & Olaf Sporns, Department of Psychological and Brain Sciences, Indiana University

materials iconmaterials icon Evolution of Neural Complexity

Abstract: We analyze evolutionary trends in artificial neural dynamics and network architectures specified by haploid genomes in the Polyworld computational ecology. We discover consistent trends in neural connection densities, synaptic weights and learning rates, entropy, mutual information, and an information-theoretic measure of complexity. In particular, we observe a consistent trend towards greater structural elaboration and adaptability, with a concomitant and statistically significant growth in neural complexity.

3/6 Stanley Wasserman, Statistics, Sociology, and Psychological and Brain Sciences, Indiana University

Statistical Analysis for Network Science

Abstract: This talk highlights the wide range of statistical analyses that are part of network science. Of particular importance are the exponential family of random graph distributions,  known as p*, and recent work on robustness and resistance of network data when actors and/or relational ties are missing or removed.

3/13 - 3/17 Spring Break

3/20 Eszter Hargittai, Northwestern University - Talk was cancelled.

materials iconmaterials icon Cross-Ideological Discussions among Top Conservative and Liberal Bloggers

Abstract: Information technologies make both interpersonal and one-to-many communication easily accessible to users having led to many speculations about their potential for influencing political communication. This paper explores the extent to which contemporary online political discussions on blogs have a cross-ideological component. Through a look at the interactions among the most popular conservative and liberal blogs, the paper considers whether authors representing opposing ends of the ideological spectrum engage each other in conversation. An analysis of linkages among such blogs sheds light on whether people of different political persuasions participate in any idea exchange online. The paper tests hypotheses about fragmentation and looks at whether widespread use of the Internet encourages dissenting political views to flourish or whether the Web merely offers a safe haven for everyone by isolating people with different opinions from each other.

3/27 David R. Heise, Sociology, Indiana University

materials iconmaterials icon Delineating Social Institutions From Semantic Networks of Role-Identities

Abstract: Dictionary definitions provide an accessible and commonsense body of data describing the cultural understandings that individuals have about role-identities. This research analyzes cross-references between definitions of several hundred identities to see whether social institutions can be viewed as confluences of identity meanings. I created a zero-one adjacency matrix by linking identities to the concepts given in their definitions. I then computed boolean powers of the adjacency matrix to simulate the process of looking up words that definitions contain. Principal components analysis of the result organized identities into clusters corresponding to standard social institutions, like family, education, medicine, work, law, religion. The analysis sub-divided some standard institutions in interesting ways, and additionally it identified sexuality as an incipient social institution.

4/3 Santo Fortunato, SoI, Indiana University

materials iconmaterials icon Egalitarian Search Engines

Abstract: Search engines have become key media for our scientific, economic, and social activities by enabling people to access information on the Web in spite of its size and complexity. On the down side, search engines bias the traffic of users according to their page-ranking strategies, and some have argued that they create a vicious cycle that amplifies the dominance of established and already popular sites. We show that, contrary to these prior claims and our own intuition, the use of search engines actually has an egalitarian effect. We show that the search behavior by users mitigates the attraction of popular pages, directing more traffic toward less popular sites.

4/10 Aonan Tang & John Beggs, Physics, Indiana University

materials iconmaterials iconLocal cortical networks: Functional topology and dynamics

Abstract: The average cortical neuron makes and receives about 1,000 synaptic contacts. This anatomical information suggests that local cortical networks are connected in a fairly democratic manner, with all nodes having about the same degree. But the physical connections found in the brain do not necessarily reveal how information flows through the network. Here we will describe our ongoing work to uncover functional connectivity from living networks of cortical neurons in vitro. We use both acute cortical slices and cortical slice cultures which can be kept alive for periods of about 10 hrs. Our first experiments with 60-channel microelectrode arrays did not allow us to get a clear picture of functional network topology. Our more recent work with a 512 electrode array system (in collaboration with Alan Litke of UC Santa Cruz) has allowed us to overcome many of these initial difficulties. We have also made improvements in the way we measure information transfer between recording sites. We will present these new results and discuss the implications they have for cortical information processing.

4/17 Alessandro Flammini, SoI, Indiana University

materials iconmaterials icon A Simple Approach to Species' Lifetime Distribution in Ecology

Abstract: Since the seminal work of Lotka and Volterra, Ecology has offered the inspiration to several unsophisticated yet insightful approaches that found thereafter a ready application to the more general field of Complex Systems. Strong of this excuse, we address with a zero-th order evolutionary model the issue of taxa's lifetime distribution. Altough the model is simple enough to be exactly solvable and makes no specific assumptions on the pattern of interaction between species, it offers a natural explanation to several, apparently conflicting, empirical data collections.

4/24 Stephen C. North, AT&T Labs

materials iconmaterials icon Connection Subgraphs

Abstract: Measuring distance or some other form of proximity between objects is a standard data mining tool. Connection subgraphs were recently proposed as a way to demonstrate proximity between nodes in networks. We propose a new way of measuring and extracting proximity in networks called "cycle free effective conductance'' (CFEC).  Our proximity measure can handle more than two endpoints, directed edges, is statistically well-behaved,
and produces an effectiveness score for the computed subgraphs. We provide an efficient algorithm. Also, we report experimental results and show examples from several collaboration and communication networks. The proposed method usually produces results that are readily visualized.

We plan to continue this talk series in Fall 2006.
Please contact Katy Börner if you are interested in presenting.