A theory driven, spatially explicit agent-based simulation to model the economic and social implications of urban regeneration

We model the economic mechanics of housing regeneration employing the rent-gap theory proposed by Neil Smith in 1979. We discuss the conditions for successful regeneration in theory, using an abstract representation of a city, then try and evaluate the possible outcomes of an actual regeneration programme in Salford, England in terms of property prices and area social composition

Agent-based modelling of urban economic and cultural dynamics under the rent-gap hypotheses

This work proposes a theoretically grounded, generative approach to the study of urban dynamics, based on the Critical Geography line of thought. We implemented a variant of the ’Rent-Gap theory of gentrification’ in a set of agent- based models of varying degrees of abstraction. A stylised model of the theory - coupled with residential mobility and cultural exchange in a city-wide context - is capable of reproducing certain observed dynamics of the past century of urbanisa- tion. Cycles of investment, the formation of persistent pockets of disinvestment, the emergence and dissolution of culturally homogeneous areas, and phenomena such as gentrification were all dynamics emerging in the simulation solely as the product of profit-driven investment in housing. A more descriptive version of the model, informed with official data derived from the UK Census and the Land Registry, provides an empirical validation of the core tenets of the theory in the context of contemporary British cities. The descriptive model is also employed to hypothesise on the mechanics and possible outcomes of large scale regeneration programmes, demonstrating a potential impact in the formulation and evaluation of urban policy. Ultimately, this work wishes to challenge the view that theory might be an un- necessary extravagance in an era of large datasets and suggestions of ’algorithmic governance.’ At the same time, it wishes to highlight the actuality and insightfulness of the critical geographical approach, especially in the wake of the decidedly urban nature of the current economic crisis

The airification of cities: making sense of the impact of peer to peer short term letting on urban functions and economy

This paper explores spatial and economic dynamics arising from the diffusion of short termnletting across Italian cities. The study is based on a vast dataset comprising of all the properties listed on the AirBnB website in 14 cities, during the year 2015. We start by examining the relationship between airbnb´s offer and general tourist flows, and demonstrate a strong correlation between the two in all the cities considered, suggesting that airbnb accommodation is how a well established, integral component of the Italian tourist offer. The core objective of the study is to look into the role of short term letting within the general dynamics of urban capital valorisation, and gain insight on the possible evolution of the urban functions of historic centres. To this purpose we identified urban areas with the highest economic advantage of short-term letting versus traditional long-term residential letting. Our analysis suggests that landlords in the urban cores of art cities may already be moving properties from the residential market to short term letting in great numbers, contributing to the decade-old social desertification and disneyfication of Italian historic centres. This finding is also supported by the surprisingly high proportion of residential units in historic centres listed on airBnB and, among these, the overwhelming predominance of entire homes versus single and private rooms. Such observations also seem to contradict AirBnB Inc.´s narrative regarding the actors that mostly benefit from the platform - reportedly younger tenants struggling with high rents, and families making an extra income. Our results suggest that landlords may be those more interested in the opportunities afforded by the platform, rather than resident tenants. The article concludes with a focus on two cities, Florence and Milan, which display extremely different spatial patterns of short term letting supply and demand, and an interesting relationship between the distribution of airbnb clusters and urban phenomena of different nature, such as gentrification

Exploring the effectiveness of a COVID-19 contact tracing app using an agent-based model

A contact-tracing strategy has been deemed necessary to contain the spread of COVID-19 following the relaxation of lockdown measures. Using an agent-based model, we explore one of the technology-based strategies proposed, a contact-tracing smartphone app. The model simulates the spread of COVID-19 in a population of agents on an urban scale. Agents are heterogeneous in their characteristics and are linked in a multi-layered network representing the social structure—including households, friendships, employment and schools. We explore the interplay of various adoption rates of the contact-tracing app, different levels of testing capacity, and behavioural factors to assess the impact on the epidemic. Results suggest that a contact tracing app can contribute substantially to reducing infection rates in the population when accompanied by a sufficient testing capacity or when the testing policy prioritises symptomatic cases. As user rate increases, prevalence of infection decreases. With that, when symptomatic cases are not prioritised for testing, a high rate of app users can generate an extensive increase in the demand for testing, which, if not met with adequate supply, may render the app counterproductive. This points to the crucial role of an efficient testing policy and the necessity to upscale testing capacity

Social integration as a determinant of inequalities in green space usage: insights from a theoretical agent-based model

Visiting urban green spaces (UGS) benefits physical and mental health. However, socio-economic and geographical inequalities in visits persist and their causes are under-explored. Perceptions of, and attitudes to, other UGS users have been theorised as a determinant of visiting. In the absence of data on these factors, we created a spatial agent-based model (ABM) of four cities in Scotland to investigate intra- and inter-city inequalities in UGS visiting. The ABM focused on the plausibility of a ‘social integration hypothesis' whereby the primary factor in decisions to visit UGS is an assessment of who else is likely to be using the space. The model identified the conditions under which this mechanism was sufficient to reproduce the observed inequalities. The addition of environmental factors, such as neighbourhood walkability and green space quality, increased the ability of the model to reproduce observed phenomena. The model identified the potential for unanticipated adverse effects on both overall visit numbers and inequalities of interventions targeting those in lower socio-economic groups

Quando il voto parla di disagio e della crisi del sogno europeo. Opinioni sulla brexit

I risultati del referendum avvenuto nel Regno Unito il 23 giugno 2016, denominato Brexit (“British exit”), hanno animato all’indomani dell’evento un intenso dibattito e copiosi sono stati i tentativi di esplorare gli esiti, in parte inaspettati, in relazione alle caratteristiche socio-demografiche della popolazione del Regno Unito piuttosto che alla appartenenza politica dei votanti. La domanda che ci poniamo è se l’espressione di voto del Brexit abbia davvero a che fare con l’Unione Europea o non sia stata forse la manifestazione di altri fenomeni. Se non siano, quindi, altre le dimensioni che hanno influenzato la scelta, come il benessere, la sicurezza, lo stato di salute delle economie locali

THE AIRIFICATION OF CITIES. MAKING SENSE OF THE IMPACT OF PEER TO PEER SHORT TERM LETTING ON URBAN FUNCTIONS AND ECONOMY

An in-depth look into the mechanics of short term rentals in Italy. The study is based on a vast dataset comprising of all the properties listed on the Airbnb website in 10 major cities in the years 2015, 2016 and 2017. We discuss the spatial patterns of Airbnb supply and demand within and between cities, we then hypothesize on the possible drivers of the Airbnb offer and suggest a possible way to assess whether Airbnb supply could be driven by an economic advantage of short-term over long term letting. We also discuss the way the benefits of this particular incarnation of the sharing economy are shared among participants. Finally, we conclude by presenting a possible alternative way of regulating Airbnb

Situating Agent-Based Modelling in Population Health Research

Abstract Today’s most troublesome population health challenges are often driven by social and environmental determinants, which are difficult to model using traditional epidemiological methods. We agree with those who have argued for the wider adoption of agent-based modelling (ABM) in taking on these challenges. However, while ABM has been used occasionally in population health, we argue that for ABM to be most effective in the field it should be used as a means for answering questions normally inaccessible to the traditional epidemiological toolkit. In an effort to clearly illustrate the utility of ABM for population health research, and to clear up persistent misunderstandings regarding the method’s conceptual underpinnings, we offer a detailed presentation of the core concepts of complex systems theory, and summarise why simulations are essential to the study of complex systems. We then examine the current state of the art in ABM for population health, and propose they are well-suited for the study of the ‘wicked’ problems in population health, and could make significant contributions to theory and intervention development in these areas

Paesaggio, cinema e fantasia: trent’anni di Italia nei film

Dal nord al sud, città e campagne italiane sono set cinematografici che ci restituiscono le immagini di un’Italia molteplice e variegata. Il database IMDb (Internet Movie Database) raccoglie ben 13.550 film girati in Italia dal 1989 ad oggi. Nella finzione cinematografica non tutti sono ambientati in Italia, ma lo è la maggior parte. Il nostro contributo parte da questi luoghi e dall’analisi del database che li raccoglie e ha un duplice obiettivo. In primo luogo desidera esaminare la geografia e la localizzazione della produzione cinematografica che ha avuto come sfondo l’Italia e, in seconda battuta, analizzare il ruolo svolto dal paesaggio nell’ambito della narrazione cinematografica, attraverso un focus specifico su alcuni film ambientati a Siena e nei dintorni. Lo studio dopo un breve paragrafo di carattere introduttivo su paesaggio e cinema (§ 2), presenta l’analisi spaziale del database IMDb (§3), affronta il tema del paesaggio italiano in relazione ai film selezionati e ai generi (§ 4), proponendo, infine, alcune riflessioni sull’impatto concreto che i film hanno nel determinare una maggiore attrattività dei luoghi che ospitano i set cinematografici (§ 5