Cultural facilities tend to cluster (in Tel Aviv)

In New York City there is the theater district. In London there is the west end. In Tel Aviv the cultural facilities seem to be randomly distributed. But, are they?

Gilles Benguigui, Idan Porath and I spent some time examining the variety of such facilities in Tel Aviv. First we used the old nearest neighbor method to identify clustering.

The method calculates the ratio between the average short distance between every two points and the expected average short distance of completely spatially random distribution. The ratio of the two is an index for the spatial point distribution and for spatial order.

The method is subject to some well-known drawbacks. It indicates a random distribution of points in cases that there are some clusters with random distribution of points inside the clusters. Also, the results are sensitive to the choice of boundary of the area within which the points are distributed. When the boundary of a geographic entity is ill-defined defined, it is difficult to apply the method.

To deal with this problem we created the all distances analysis. It is free of these defects. The all distances analysis method takes into account the distances between every point to all other points in the examined area.

We concluded that despite first appearances the cultural facilities cluster. Furthermore, there are several distinct clusters, each possessing particular characteristics. These characteristics were confirmed by a detailed survey of users.

Semester break at the Technion

It is the end of the Fall/Winter semester at the Technion. We start late (in October) and finish in February. The Spring semester will start in mid-March and end in the beginning of July.

The upshot is that I am off to a conference and visits to various campuses in the USA.

Jerusalem will be environmentally friendly, but ultra-orthodox

Jerusalem is a relatively poor city. It is the home of a large ultra-orthodox population that is characterized by men who study Torah and women that produce very many children and work to support their families. It is also the home of government employees. Although there is a high-tech industry in Jerusalem, many of its employees reside outside city limits.

For many years now, policy makers in Jerusalem have targeted ways to attract new, young and professional population to the city. One of the means that has been proposed is to create a new stock of housing for these families, away from the religious neighborhoods. It was hoped that by so doing the stigma of Jerusalem as a place dominated by "blue laws" will be replaced by an image of comfortable suburban living in the midst of nature in the Judean hills.

A land- use plan was commissioned from the Israeli/Canadian architect Moshe Safdie. The plan proposed 20,000 housing units west of the city around the main road connecting Jerusalem with the center of the country.

Today, the Israel National Planning Board rejected the plan after a prolonged debate to the sound of vocal protest from various groups wishing to preserve the green areas around the city. The mayor of Jerusalem has adopted the view that it is possible to create a sufficient stock of housing within the current city limits. Based on a new study he claims that it is possible to build 40,000 housing units within the city.

There is no doubt that dense urban fabric is to be preferred. It creates a smaller environmental footprint by encouraging the use of public transportation facilities and lowers CO2 emissions. However, there may be a significant cost associated with the new policy. It is my suspicion that Jerusalem will find it difficult to attract young, upwardly mobile families and that the outflow of young people to Tel Aviv will continue. It is likely that we will have a green , non-pluralistic and relatively poor capital city.

High-rise residential buildings and Pigou

This Thursday I was an "expert witness" before the Israel National Planning Board concerning an objection launched by a local Planning Board to a 1,200 residential complex that includes a number of high-rise buildings. Among the arguments that were presented against the project was the high cost of maintaining high-rise buildings and the possibility that over time the project will turn into a slum. An additional argument of the officials of the local Board was that the quality of life of the residents in the complex will be adversely affected by the noise of the highway and train station next to the complex.

These arguments should be contrasted to the arguments of Ed Glaeser in a recent article in the New York Times
[URL: http://www.nysun.com/article/47626]. Ed Glaeser points out the contribution of Manhattan residents to environmental quality. They use less land per capita and their usage of private cars is much smaller than that of other cities. All this is due to the high density in Manhattan.

In this spirit I suggest that we encourage the construction of high-rise, dense residential complexes next to major transportation infrastructure and that we make them accessible to lower income residents by appropriate negative Pigou taxes, in relation to their contribution to the reduction of negative externalities. This is not to say that higher income residents should not benefit from such taxes.

It is common for economists to advocate taxes on negative externalities in the context of market activities. The so-called Pigovian taxes (after Arthur Pigou) should be levied on producers who pollute the environment to encourage them to reduce pollution, and to provide revenue which may be used to counteract the negative effects of the pollution. Greg Mankiw keeps track of economists who advocate Pigovian taxes. [See http://gregmankiw.blogspot.com/2006/09/rogoff-joins-pigou-club.html
Also, see the manifesto of the Pigou Club: http://gregmankiw.blogspot.com/2006/10/pigou-club-manifesto.html].

Andrew Gelman says that economists are fun

I could not help it and have to direct your attention to Andrew Gelman's blog http://www.stat.columbia.edu/~cook/movabletype/mlm/. Gelman wrote:

"Sarah Igo came yesterday in our seminar to tell us about her recent book, The Averaged American. It was a lot of fun, and she commented that when she speaks to historians, they just let her speak, but we're more fun because we interrupt her frequently. I assured her that if interruption=fun, then economists are the most fun of all..."

I have to add that Israeli economists are extra fun...

Clusters of high-rise building in Tel Aviv

Two colleagues (Lucien Benguigui, our PhD student Rafi Roth) and I just completed a major study concerned with the evolution of high-rise buildings in Tel Aviv. We conducted empirical analyses of the temporal and spatial evolution of the city in 3D and we built corresponding cellular automaton (CA) simulation models.

Until some 15 years ago economists were satisfied with observing cities through a prism of stylized facts and the Alonso type mono-centric urban model. The recognition of the existence of "edge cities" led to models with multiple centers. Both types of models suggest that high-rise buildings tend to cluster in space.

In our study clusters are defined as spatially continuous concentrations of buildings of pre-defined heights. We succeeded to generate 3D clusters by means of our cellular automaton model. The rules of behavior are relatively simple and have an economic intuition. More recently we attempted to identify empirically clusters of high-rise building in Tel Aviv over time with the help of GIS.

The results are interesting. The frequency distribution of building heights displays twin peaks. More, interesting, using a variety of measures we identified clusters already in the 1970s. However, over time the clusters tend to weaken.

These days we parade our results at various conferences.

Figure 1 Distribution of heights in Tel Aviv 2003

Figure 2 Distribution of heights of high buildings in Tel Aviv 2003 with exponential fit

Is there technology based solution to global warming?

Last November I wrote about the important research of Nir Shaviv and his co-researchers at the Hebrew University in Jerusalem concerning global warming [see http://urbaneconomics.blogspot.com/2006/11/global-warming-alternative-viewpoint.html]. According to Shaviv's model, recently (partly) tested at CERN (see http://www.sciencebits.com/CO2orSolar), the major source of influence on the earth's temperature is solar activity that causes ionization and cloud formation.

Added evidence was provided by the Danish National Space Center (DNSC) Sky experiment that was published in the Proceedings of the Royal Society. Shaviv reported as follows [http://www.sciencebits.com/SkyResults]:This is the Royal Society's press release on the publication of Svensmark et al.: “Using a box of air in a Copenhagen lab, physicists trace the growth of clusters of molecules of the kind that build cloud condensation nuclei. These are specks of sulphuric acid on which cloud droplets form. High-energy particles driven through the laboratory ceiling by exploded stars far away in the Galaxy - the cosmic rays - liberate electrons in the air, which help the molecular clusters to form much faster than atmospheric scientists have predicted. That may explain the link proposed by members of the Danish team, between cosmic rays, cloudiness and climate change.”

Now the Shaviv team proposes a theoretical model that provides an insight concerning a possible technology that can reduce global warming. If solar activity does not provide the means for cloud formation over the Pacific Ocean, a set of giant lasers firing horizontally high in space can create the required effect.

I am far from capable of judging these ideas. But in the absence of contrary evidence, it makes me skeptical about size of the anthropogenic influence on global warming and hopeful that technology will provide the answer. I would like to hear some cogent discussion of the Shaviv hypotheses.