In the real world, cities exist because of external economies associated with the geographic concentration of firms within a city. Of course, such a geographic proximity with input providers and consumers, would at first reduce transportation costs. But why cities, information cities, i.e. large agglomerations of people and economic activity emerge in the virtual world? In the Internet, transpo...

Understanding the backgrounds and interest of the people who are consuming a piece of content, such as a news story, video, or music, is vital for the content producer as well the advertisers who rely on the content to provide a channel on which to advertise. We extend traditional search-engine query log analysis, which has primarily concentrated on analyzing either single or small groups of qu...

OBJECTIVE To estimate the effects of red light camera enforcement on per capita fatal crash rates at intersections with signal lights. METHODS From the 99 large U.S. cities with more than 200,000 residents in 2008, 14 cities were identified with red light camera enforcement programs for all of 2004-2008 but not at any time during 1992-1996, and 48 cities were identified without camera program...

Large cities with multi-modal traffic systems are complex that need to be understood to help analyze and make policy decisions. Understanding such complex systems requires simulation, experimentation and observation. We have built a MUST system to simulate big cities with multi-modal traffic system with large number of agents (humans), each participating in many movement activities. Building su...

Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associ...

Consistent with the current emphasis on performance-based accountability in K-12 education, several states and a few local districts have introduced school-based incentive programs. This paper provides one of the few evaluations of the effects of such programs on student outcomes. Using a panel data set for schools in large Texas cities, it measures the gains in student performance in Dallas re...

There is much enthusiasm currently about the possibilities created by new and more extensive sources of data to better understand and manage cities. Here, I explore how big data can be useful in urban planning by formalizing the planning process as a general computational problem. I show that, under general conditions, new sources of data coordinated with urban policy can be applied following f...

Cities the world over are highly fragmented. The fragmentation of the built-up area cities by the open spaces interpenetrating them is a key attribute of urban-sprawl, and sprawl as fragmentation, as distinct from sprawl as lower-density development, is now a universal feature of cities. Using satellite images and census data for 1990 and 2000 for a global sample of 120 cities, we find that cit...

Smart cities are high on the political agenda around the globe. However, planning smart cities and deploying applications dealing with the complex problems of the urban environment is a very challenging task that is difficult to be undertaken solely by the cities. We argue that the uptake of smart city strategies is facilitated, first, through the development of smart city application repositor...

This paper provides a survey and guide to the literature relevant to urbanization and economic development. The paper starts with some basic facts and trends about urbanization worldwide. It then reviews the traditional twosector urban-rural model, but focuses on the modern version, Krugman’s coreperiphery model. However, two sector models do not capture the notion of an economy composed of man...