1. 특강/Special Lecture: 2018-01-09(화/Tue) 13:00~14:30
2. 세미나/Seminar 1: 2018-01-11(목/Thu) 13:00~14:30 
3. 세미나/Seminar 2: 2018-01-16(화/Tue) 13:00~14:30

- 장소/Venue: N25 #3229 백남준홀/PAIK Nam June Hall

Gourab Ghoshal 교수 
현) 미국 로체스터대학교 Physics, Computer Science and Mathematics 학부 
미시간 대학교 물리학 박사 
전) 하버드 대학교 지구 행성 과학, 의과대학 및 노스웨스턴 네트워크 연구단 연구펠로우 
전) MIT 미디어랩 연구펠로우 




1. 특강/Special Lecture: 2018-01-09 (화/Tue) 13:00~14:30

Title: Seeing the world through the lens of networks

Abstract:
Most things in the world are made up of systems of interacting parts, such that their global behavior is greater than the sum of their constituents. Such systems are often referred to as Complex Systems, with their defining features being the fact that they form Complex Networks and that their components interact in a non-linear fashion. Examples of Complex Systems are the human brain, financial markets, social media, urban systems, infrastructural entities such as the internet, knowledge networks like the world wide web and indeed any socio-economic construct. In this lecture, I will focus on the complex networks part of the equation and highlight the advantages and new insights afforded by modeling systems as networks.
The lecture will serve as a gentle introduction to the field of network science and does not assume any prior or detailed technical knowledge.
  
 
2. 세미나/Seminar 1: 2018-01-11 (목/Thu) 13:00~14:30
 
Title: Ranking as a low-dimensional signal of socio-economic processes in complex systems.
 
Abstract:
Consider the thought process behind the purchase of a product, where a potential buyer leverages several inputs (location, social milieu, advertising in media, product literature, social trends as marked by Twitter etc.) and converts this high-dimensional space into a single input: priority. Yet priority is nothing but ranking of an object and therefore serves as a coarse-grained (low-dimensional) metric of myriad processes occurring in socio-economic systems. Indeed,
one might say the world is addicted to ranking: everything from the sales of products to the careers of scientists to the performance of countries in international trade, are driven by measured or perceived differences between them. Yet, little scientific attention is devoted to the dynamical and generative processes that underlie the ranking process. This is understandable as ostensibly the sheer diversity of the systems under consideration make it a rather daunting task to seek any systemic or universal properties.
 
Having said that, in this talk I’ll attempt to do just that. I’ll begin by introducing the concept of ‘’ranking stability” as it relates to eigenvalue algorithms—such as Google’s PageRank—and then move on to the empirical examination of a plethora of temporal datasets that enables us to develop a “phenomenological theory” capturing the dynamics of ranking. Implications and future directions will also be explored.
 
 
3. 세미나/Seminar 2: 2018-01-16 (화/Tue) 13:00~14:30
 
Title: Urban morphology and structural invariants in street networks.
 
Abstract:
Streets networks are the primary facilitators of movement in urban systems, allowing residents to navigate the different functional components of a city. Since navigability is a key ingredient of socioeconomic activity, roads represent one of its most important infrastructural components and a large body of work has elucidated its structural properties. Yet more than the physical layout, it is the sampling of street networks that serves as a true fingerprint of the complex interactions between people, and the flow of goods and services in urban systems, a feature of which there is limited understanding.
 
In this talk, I’ll describe attempts to fill this gap, by describing a systematic mesoscale study of street morphology (shape of sampled routes) through the introduction of a novel metric termed , inness. The inness encapsulates the direction, orientation and length of routes, thus revealing the morphology of connectivity in street networks, including the distribution of implicit socioeconomic forces that may inform routing choices. In particular, this metric enables us to put functions of individual streets in the context of the dynamics of the whole city (Broadway or Fifth avenue in NYC, for instance), linking local structures to large-scale urban organization.
 
The dynamics of a city of course is intricately related to the flow of people and goods and services, a structural measure of which is the betweenness centrality. I’ll show that the global distribution of betweenness is an invariant quantity once one accounts for the proper scale and provide a qualitative analytical description, based on Minimal Spanning Trees embedded in 2D space, to explain this remarkable invariance. Practical implications of this observation as it relates to urban planning will be explored.