Using off-the-shelf Global Positioning System (GPS) units, we reconstruct buildings in 3D by exploiting the reduction in signal to noise ratio (SNR) that occurs when the buildings obstruct the line-of-sight between the moving units and the orbiting satellites. We measure the size and height of skyscrapers as well as automatically constructing a density map representing the location of multiple ...

The estimation and projection of the urban population is based on observed changes in the proportion of the population living in urban areas. Therefore, the quality of the estimates and projections made is highly dependent on the quality of the basic information permitting the calculation of the proportion urban. Such information consists normally of complete counts of both the total population...

OBJECTIVE To determine the prevalence and pattern of smoking amongst Pakistanis. SAMPLING DESIGN: A two stage stratified sample design was adopted for the survey, Primary Sampling Units (PSU's) and Secondary Sampling Units (SSU's). SETTING Urban and Rural, Pakistan 1990-94. SUBJECTS Stratified systematic sample of 9441 males and females aged 15 years and above. MAIN OUTCOME MEASURES Smoke...

Two decades of China's urban housing reform has produced significant quantitative and qualitative improvements. Despite various policies aimed to promote owner-occupied residential housing, the extent of commodification has been limited, and, in particular, most ownership transactions are independent of market considerations. This paper analyzes the reasons why significant commercial owner-occu...

All cities known to social scientists and historians have neighborhoods. People living in urban settings universally organize important aspects of their lives on a spatial scale that is intermediate between the household and the city. Urban authorities also tend to organize administrative ac­ tivities such as tax collection and record keeping on a similar scale. The spatial relationship between...

Slums provide shelter for nearly one third of the world’s urban population, most of them in the developing world. Slumulation represents an agent-based model which explores questions such as i) how slums come into existence, expand or disappear ii) where and when they emerge in a city and iii) which processes may improve housing conditions for urban poor. The model has three types of agents tha...

This short paper constitutes the first phase of a long-term project focused on probing American urban culture by examining the hyperlinks and text of personal weblogs. It discusses methods of extracting geographic location information from weblogs and ways of indexing weblogs to city units. After a brief introduction to the broader research plan, the paper proposes a process to automatically ex...

This paper proposes four metrics to measure sprawl in metropolitan regions as marginal changes in land use over time. The metrics (change in urban housing unit density, marginal land consumption per new urban household, housing unit density in newly urbanized areas and percent of new housing units located in previously developed areas) are computed for all 329 metropolitan areas in the continen...

Background & Aims of the Study: Due to one-way flow of water in rivers Guilan, pollution trade theory and the system of Ratio-Trade (TRS) and Streeter - Phelps equation has been used. This system, with a view of the river self- purification and how the distribution and transport of pollutants, determined Ratio-Trade system (TRS) between the units and using this method offers optimal pat...

BACKGROUND The purpose of this study was to compare technical and scale efficiency of primary care centers from the two largest Greek providers, the National Health System (NHS) and the Social Security Foundation (IKA) and to determine if, and how, efficiency is affected by various exogenous factors such as catchment population and location. METHODS The sample comprised of 194 units (103 NHS ...