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Allen J. Scott
Edited by André Torre and Delphine Gallaud
John Aldo Lee, Cyril de Bodt, Ludovic Journaux and Lucile Sautot
Dimensionality reduction aims at representing high-dimensional data in a lower-dimensional representation, while preserving their structure (clusters, outliers, manifold). Dimensionality reduction can be used for exploratory data visualization, data compression, or as a preprocessing to some other analysis in order to alleviate the curse of dimensionality. Data structure is usually quantified with indicators, like covariance between variables, or pairwise proximity relationships, like scalar products, distances, similarities, or neighbourhoods. One objective of this chapter is to provide an overview of some classical and more recent methods of dimensionality reduction, to shed some light on them from the perspective of analyzing proximities, and to illustrate them with multivariate data that could be typically encountered in social sciences. Complementary aspects like quality assessment and alternative metrics are briefly developed.
Edited by André Torre and Delphine Gallaud
Edited by Miloš N. Mladenović, Tuuli Toivonen, Elias Willberg and Karst T. Geurs
Michiel van Meeteren
A commonly encountered perspective in textbooks explains the existence of cities as function of being in the middle of something. Cities are centres of political, cultural, economic and/or religious life, explaining the large religious buildings, stock exchanges or pantheons in the city. According to many (for instance, Bird 1977, p. 1; Friedmann 1968, p. 236; Lefebvre 1974 , pp. 331–34), the associated notion of centrality amounts to a key building block of what the city is about. This chapter surveys the urban theories that try to understand the benefits, the side effects and the desires associated with being in the middle. Urban centrality’s core idea is that being in the middle exerts spatial effects. The middle can induce a desire to be there, a centripetal tendency. Authors (for example, Bobek 1927) emphasize the magnetic attraction of urban places, invoking images of being pulled to bright lights in the big city. Alternatively, being in the middle can be something we are pulled away from, a centrifugal tendency, for instance when the middle is too expensive, too crowded or too dirty. These centripetal and centrifugal tendencies were first theorized as urban phenomena by Schlüter (1899, cited in Müller-Wille 1978, p. 50) in Germany and by H.G. Wells (1902, cited in Bird 1977, p. 104) in the anglophone world, and were further elaborated in the subsequent century. Colby (1933) provides an overview of what these tendencies entail in early twentieth-century cities. The balance between countervailing centripetal and centrifugal tendencies generates distinctive divisions of labour and zonal patterns of urban fabric within a particular technological conjuncture. Colby (1933) notes how new technological possibilities, transportation modalities and changing economic fortunes continuously upset these equilibriums and change centralities (Van Meeteren et al. 2016a).
Michael Barke and Peter J. Taylor
In her classic theory of economic development Jane Jacobs (1971) identifies explosive city growth as the key mechanism. Less well known is her description of a broader urban consequence of this rapid change that she terms the rounding out of the city, a new array of goods and services for the local population. Her list of these for her ‘home town’ Scranton, Pennsylvania, in the first half of the twentieth century are given as a zoo, a museum of natural history, a central public, reference library, several hospitals, ‘several stuffy but imposing clubs’, departmental stores, city departments for fire-fighting and public health services, and a trolley-car system (Jacobs 1970, p. 160). That is, although Jacobs defines a city as a settlement that experiences one or more momentous economic spurts, it only begins to more broadly function as we expect of a city during its period of rounding out. In this chapter we equate Jacobs’s rounding out with development of an urban associational life, unplanned and voluntary creation of a thick layer of small social networks riding the rapid economic changes. They can be interpreted as buffers against the uncertainties and anonymity consequent upon urban growth (Neal 2013, p. 41). This process is explored for Newcastle upon Tyne, England, in the nineteenth century. Our choice of Newcastle for this case study follows on from previous research on economic spurts through urban demographic growth that found this city to be one of the fastest growing cities in the world for two periods, 1800–49 and 1850–99 (Taylor et al. 2010). Subsequently we have described this economic success in detail, showing how Newcastle’s division of labour grew in complexity as it was transformed from a centre for coal export at the beginning of the nineteenth century to become a large city-region and industrial powerhouse by century’s end (Barke and Taylor 2014). This was also a period of massive rounding out in the form of a vast diversity of voluntary associations. Thus huge economic change was accompanied by equally momentous cultural, political and social additions to the activities of the city. In this contribution we outline the methods we have deployed to describe and analyse a growing associational life behind transformation into a multifaceted urban society.
Kathy Pain and Shuai Shi
In a globalising world economy, cities have increasingly come to be defined not by the size of their built up area or population but by their functions in networks that connect them to capital flows that cross territorial boundaries (Rozenblat 2010). As Sassen (1991, p. 631) wrote it in her global cities book, ‘massive trends toward spatial dispersion of economic activities at the metropolitan, national and global level, which we associate with globalisation, have contributed to a demand for new forms of territorial centralisation of top-level management and control operations’. As centralities for management and control functions in network enterprises operating at different spatial scales, globalising cities can be expected to be economically vibrant owing to their role in facilitating the circulation and accumulation of intellectual and financial capital. Moreover, according to protagonists of Jacobs (1984), the vibrancy of these cities spills over metropolitan boundaries to form prosperous globalising city regions (Scott 2001a, 2001b; Hall and Pain 2006). A new paradigm of city networks, functions and flows has therefore overtaken the traditional paradigm of places and territorial borders as the structure of the contemporary global space economy. In the networked economy that has been evolving for half a century, it follows that city regions are differentiated not only by their physical pattern of urban development, but also by their functional pattern in network space. In consequence, city-region spatial form (morphology) and city-region Jacobsean economic expansion, while interrelated, are distinctive development processes that should not be confused with each other (Taylor and Pain 2007; Pain 2012). However, the concept of polycentrism has referred to morphological space without paying due regard to network space, functions and flows, for almost two decades in a policy to rebalance uneven regional economic development in Europe (European Commission 1999; Davoudi 2003; Duhr and Nadin 2005; Halbert et al. 2006; Pain 2008). Thus, European spatial planning strategy has promoted the development of polycentric urban regions (PURs) based on examples of regions populated by many similar-sized urban centres, such as the Randstad region in the Netherlands and the Rhine-Ruhr region in Germany, which are regarded as a superior spatial form to monocentric regions dominated by one centre such as South East England and the French Paris region.
Karima Kourtit, Peter Nijkamp and Tigran Haas
Since the early history of mankind, human beings have tried to build settlements that were fit for purpose. In a nomadic or low-technology society human settlements had to be by necessity flexible and small. Large cities hardly existed and were only built to demonstrate or strengthen political and military power. However, even these cities were – compared with current standards – relatively small and their management demanded enormous efforts (for example, import of agricultural produce, fresh water, sewerage systems and jobs for citizens). Cities of more than 1 million inhabitants were, until a few centuries ago, a miraculous urbanistic exception (see Tellier 2009). This situation lasted in most countries until the age of the Industrial Revolution (mid-nineteenth century) when cities started to grow. With the worldwide uninterrupted population growth since two centuries ago (the first demographic revolution), cities went through an accelerated growth path. This has led over the past half a century to a double urbanization process: most cities were growing and became large cities, while several large cities reached the size of megacities (more than 10 million inhabitants). This development is clearly demonstrated in China which currently has more than 60 cities with a population exceeding 1 million inhabitants, while the number of megacities in this country is also showing rapid growth. Worldwide, we witness a megatrend towards more and bigger cities. This revolutionary phenomenon in the history of urbanism is sometimes termed the New Urban World (Kourtit 2019). In the past decade, our world has reached a stage where more people are residing and living in urban areas than in rural areas. This new species of mankind is sometimes named the homo urbanus. The city has become the most attractive settlement place for the majority of people on our planet. The United Nations has, therefore, named this new epoch in the geographic-demographic history of our world the urban century.
Brian D. Christens and Daniel G. Cooper
Community organizing occurs when residents collaboratively investigate and take collective action on issues that concern them. These issues of concern often include safety, educational quality, community development, improvements to neighborhoods and the physical environment, and access to health care, affordable housing, transportation and employment opportunities. Often, these concerns are local manifestations of macro-level forces, such as neoliberal globalization and structural racism. In order to achieve changes in local policies and systems in spite of these forces, residents often seek to build longlasting local organizing initiatives that are capable of sustaining social action, holding decision-makers and institutions accountable to address concerns of local residents across a variety of issues. Organizing is therefore a way for local residents to enhance their quality of life in tangible ways while simultaneously resisting and challenging oppressive sociopolitical forces and working to advance social justice. Many local organizing initiatives are built as coalitions or federations of smaller geographically- or institutionally situated efforts. Just as labor-organizing federations support efforts across many different workplaces, community organizing federations (often termed initiatives) support efforts within and among community centers, faith-based institutions, schools, neighborhood organizations, and other nonprofit and voluntary organizations. For example, the Southwest Organizing Project (SWOP) in Chicago currently lists 37 member institutions including faith-based institutions (for example, a Lutheran church, an Ethiopian Hebrew congregation, and the Inner-City Muslim Action Network, itself a separate federation), a number of elementary, middle, and high schools, a community development corporation, and several social service organizations. Many times, this type of federated structure is used for two purposes: (1) to equip local organizing committees or efforts within each member institution (sometimes termed affiliates), which may organize around issues of their own choosing, and (2) to create a broader federated structure that can carry out campaigns on issues of concern across the initiative or federation.