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Analyzing Urban Vitality at scale: PhD defense 2019

Analyzing Urban Vitality at scale: PhD defense 2019

Marco De Nadai

May 22, 2019
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  1. Marco De Nadai, supervised by Bruno Lepri and Nicu Sebe
    INTO THE CITY:
    a Multi-Disciplinary
    Investigation of Urban Life

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  2. 2
    Cities, very difficult to explain
    Not only agglomeration of
    residents, factories, shops
    • Millions of individuals
    • Continuously evolving
    A small change generates a
    cascading throughout
    COMPLEX SYSTEM

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  3. 3
    Cities have always been studied
    IDEAL CITY
    (XV century)
    SYSTEM
    (XIX century)
    LIVING ORGANISM
    (XX century)

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  4. 4
    Understand cities

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  5. 5
    Understand cities
    New methods
    New data

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  6. 6
    Describe people and places at scale
    Urban
    description
    1
    Urban
    perception
    2

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  7. 7
    CITY PEOPLE
    Multi-modal approach

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  8. Urban description
    Q: Can we describe how people experience the city?
    1

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  9. The theory: Jane Jacobs
    One of the most influential books in city
    planning
    • planning models that dominated mid-
    century planning
    • Melbourne, Toronto etc.
    9
    Klemek, C. (2011) ‘Dead or Alive at Fifty? Reading Jane Jacobs
    on her Golden Anniversary’ Dissent, Vol. 58, No. 2, 75–79.
    2
    1 3
    URBAN DESCRIPTION 4

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  10. The theory: Jane Jacobs
    • Written in 1961
    • Not empirically tested until 2015
    • Tested in Seoul, from costly surveys
    collected in years
    • Operationalize the theory
    10
    Jacobs, Jane. The death and life of great American cities.
    Vintage, 1961
    2
    1 3 4
    URBAN DESCRIPTION

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  11. The theory: Jane Jacobs
    The theory says that:
    • Death: caused by the elimination of
    pedestrian activity
    • Life: created by a vital urban fabric at
    all times of the day
    11
    Jacobs, Jane. The death and life of great American cities.
    Vintage, 1961
    2
    1 3 4
    URBAN DESCRIPTION

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  12. The theory: Jane Jacobs
    Diversity => Urban vitality
    There are 4 diversity conditions
    12
    LAND USE
    SMALL
    BLOCKS
    AGED
    BUILDINGS
    DENSITY
    2
    1 3 4
    URBAN DESCRIPTION

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  13. Operationalize the theory
    • Land use mix
    13
    For district :
    %
    = − (
    )∈+
    %,)
    log(%,)
    )
    log ||
    %,)
    : % square footage of land use
    : {residential, commercial, recreation}
    LAND USE
    SMALL
    BLOCKS
    AGED
    BUILDINGS
    DENSITY
    2
    1 3 4
    URBAN DESCRIPTION

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  14. Operationalize the theory
    • Small blocks
    |%
    |
    %
    14
    LAND USE
    SMALL
    BLOCKS
    AGED
    BUILDINGS
    DENSITY
    2
    1 3 4
    URBAN DESCRIPTION

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  15. Operationalize the theory
    • Aged buildings:
    15
    @AB
    = ∑DEF
    G HD(IDJ ̅
    I)L
    M
    (NOF)
    N
    ∑DEF
    G HD
    =
    LAND USE
    SMALL
    BLOCKS
    AGED
    BUILDINGS
    DENSITY
    2
    1 3 4
    URBAN DESCRIPTION

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  16. Operationalize the theory
    16
    LAND USE
    SMALL
    BLOCKS
    AGED
    BUILDINGS
    DENSITY
    2
    1 3 4
    Employment density:
    |PQRSTUBV RBTRSBD|
    @WB@D
    Population density:
    |XTRYS@Z%T[D|
    @WB@D
    URBAN DESCRIPTION

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  17. Operationalize the theory
    • 6 Italian cities
    • Features to describe the Jane Jacobs
    theory
    17
    2
    1 3 4
    URBAN DESCRIPTION

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  18. What is vitality?
    • Defined in various (fuzzy) ways in
    urban science and sociology
    • There is no standard
    • Key asset for urban spaces
    • Important for companies (and retail)
    success
    • Influences the real estate market
    18
    asd
    2
    1 3 4
    URBAN DESCRIPTION

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  19. Call Detail Records
    Data collected by mobile operators for
    billing reasons
    • Unique userID
    • Gender and age
    • Geographical location (Antenna)
    • Datetime
    19
    2
    1 3 4
    URBAN DESCRIPTION

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  20. Vitality (empirical)
    • Define areas
    • We define vitality as the average
    number of people in a neighborhood
    20
    1
    %
    ||
    (
    _∈`
    | ℎ %
    |
    : set of hours (60 days x 24h)
    : area of district
    2
    1 3 4
    URBAN DESCRIPTION

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  21. Describe urban areas and vitality
    21
    VITALITY
    For each neighborhood
    Mobile data
    2
    1 3 4
    URBAN DESCRIPTION

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  22. Describe urban areas and vitality
    22
    People + Companies
    GIS
    VITALITY
    For each neighborhood
    Mobile data
    2
    1 3 4
    URBAN DESCRIPTION

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  23. Describe urban areas and vitality
    23
    People + Companies
    GIS
    Predictive
    model
    VITALITY
    For each neighborhood
    Mobile data
    2
    1 3 4
    URBAN DESCRIPTION

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  24. The log Linear Regression model
    24
    Vitality (Ground truth)
    Land Use Mix
    Employment density
    = i
    i
    + l
    l
    + ⋯ + [
    [
    +
    2
    1 3 4
    URBAN DESCRIPTION

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  25. 25
    Urban metric Standardized Beta coefficient
    Employment density 0.434***
    Intersections density 0.191***
    Housing types 0.185***
    Closeness highways -0.102***
    3rd places x closeness highways 0.07**
    Closeness parks x closeness highways -0.07***
    adj − Rl 0.77
    *** p-value < 0.001; ** p-value < 0.01;
    Describe urban vitality
    2
    1 3 4
    URBAN DESCRIPTION

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  26. Take home
    26
    De Nadai, Marco, et al. "The Death and Life of Great Italian Cities: A Mobile Phone Data Perspective."
    WWW, 2016.
    Physical characteristics
    describe and predict
    urban vitality
    2
    1 3 4
    URBAN DESCRIPTION

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  27. Urban perception
    Q: Can we link urban visual perception with the behavior of
    people at scale?
    2

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  28. Broken windows theory
    • City mismanagement
    • Dirty places
    • Poor infrastructure
    Lead to misbehavior => Crime
    Q: Are people avoiding places where
    they feel unsafe?
    28
    Wilson, James Q., and George L. Kelling. "Broken windows."
    Critical issues in policing: Contemporary readings (1982): 395-
    407.
    2
    1 3
    URBAN PERCEPTION 4

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  29. 29
    Urban perception from Place Pulse
    Salesses, P., Schechtner, K., & Hidalgo, C. A. (2013). The collaborative image of the city: mapping the inequality of urban
    perception. PloS one
    2
    1 3
    URBAN PERCEPTION 4

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  30. 30

    1
    10
    Place Pulse
    • New York
    • Boston
    • Linz
    • Salzburg
    Place Pulse 2
    • Rome
    • Milan
    PROBLEM:
    • Few images per neighborhood
    • Few labels per image
    2
    1 3
    URBAN PERCEPTION 4
    Safety perception: MIT Place Pulse

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  31. 31
    Security perception prediction
    * B. Zhou, A. Lapedriza, J. Xiao, A. Torralba, and A. Oliva. “Learning Deep Features for Scene
    Recognition using Places Database.” NIPS, 2014.
    • Learning human security perception
    • Transfer learning from Place205*, US, to Rome and Milan
    PERCEPTION
    SCORE
    [0-10]
    2
    1 3
    URBAN PERCEPTION 4

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  32. 32
    Can we predict human security perception?
    * Ordonez, Vicente, and Tamara L. Berg. "Learning high-level judgments of urban perception.” ECCV, 2014.
    Model type State of the art* Our model
    NY - NY 0.687 0.718
    NY - Boston 0.701 0.734
    Boston - Boston 0.718 0.744
    Boston - NY 0.636 0.693
    2
    1 3
    URBAN PERCEPTION 4

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  33. 33
    2
    1 3
    URBAN PERCEPTION 4
    Describe security perception
    Security perception Vitality
    Regression model

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  34. 34
    2
    1 3
    URBAN PERCEPTION 4
    Describe security perception
    2 4.4 4.6 4.8 5.0
    ety score
    DUOMO
    SAN SIRO
    QUARTO
    OGGIARO
    CITTA'
    STUDI
    BICOCCA
    0.2
    0.0
    0.2
    0.4
    0.6
    0.8
    1.0
    1.2
    Land Use Mix
    0.8 1.2 1.8 2.7 4.1 6.1 9.3
    Activity density ⇥ 10
    MILAN
    Security perception Vitality
    Regression model

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  35. 35
    Urban metric Standardized Beta coefficient
    adj − Rl 0.91
    Security perception -> presence of people
    2
    1 3
    URBAN PERCEPTION 4

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  36. 36
    Urban metric Standardized Beta coefficient
    Population density 0.155**
    Employees density 0.328**
    Deprivation -0.022
    Distance from the center -0.257**
    Security perception 0.105**
    adj − Rl 0.91
    ** p-value < 0.001; * p-value < 0.01;
    Security perception -> presence of people
    2
    1 3
    URBAN PERCEPTION 4

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  37. 37
    Urban metric Standardized Beta coefficient
    % of women (from census) 0.001
    Deprivation -0.005
    Distance from the center -0.003
    Security perception 0.020**
    adj − Rl 0.65
    ** p-value < 0.001; * p-value < 0.01;
    Security perception -> presence of women
    2
    1 3
    URBAN PERCEPTION 4

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  38. 38
    Visual elements for security perception
    HIGH SAFETY PERCEPTION
    RANDOMLY OBSCURE
    PART OF THE IMAGE
    AND PREDICT
    2
    1 3
    URBAN PERCEPTION 4
    CONTRIBUTE POSITIVELY
    CONTRIBUTE NEGATIVELY

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  39. Take home
    39
    De Nadai, Marco, et al. "Are Safer Looking Neighborhoods More Lively?: A Multimodal Investigation
    into Urban Life." ACM MM, 2016.
    Security perception can
    describe and predict
    the presence of people
    2
    1 3
    URBAN PERCEPTION 4

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  40. 40
    Describe the places at scale, automatically
    Urban
    description
    1
    Urban
    perception
    2

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  41. Applications

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  42. Housing price
    Q: Can we describe the neighborhood effect on housing price?
    3

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  43. Real estate appraisal
    • Timeless sale transactions
    • Proprietary data
    • Lack of data?
    • Neighborhood?
    43
    2
    1 3
    HOUSING PRICE 4

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  44. A data mining approach
    44
    PLACE
    Characteristics of the
    census cell
    NEIGHBORHOOD
    Description and perception
    PROPERTY
    Characteristics of the
    property
    2
    1 3
    HOUSING PRICE 4

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  45. 45
    The data
    One year of listed properties in Immobiliare.it
    • The 8 biggest Italian cities
    • 70,000 properties
    2
    1 3
    HOUSING PRICE 4

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  46. 46
    The property: textual features
    Textual features about the listed property
    • Number of rooms
    • Square meters
    • Energy compliance
    • Garden (yes/no)
    • […]
    2
    1 3
    HOUSING PRICE 4

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  47. We need context – auto-correlation
    47
    2
    1 3
    HOUSING PRICE 4

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  48. The egohoods
    48
    2
    1 3
    HOUSING PRICE 4

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  49. Features of the city
    For each of the ~ 400’000 census cells:
    • build the egohood
    • Create:
    • 10 socio-economic indexes
    • 11 urban features
    • 4 indexes of companies and jobs
    49
    2
    1 3
    HOUSING PRICE 4

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  50. 50
    XGBoost
    K-fold Cross-validation (with care!)
    = ( + )
    2
    1 3
    HOUSING PRICE 4
    Egohood features
    (e.g. land use mix)
    Property features
    (e.g. square feets)
    Housing price
    (ground truth)
    Weight/contiguity matrix

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  51. 51
    Results
    Model MAE MdAPE
    Property 148, 109 23,76%
    Property + Neighborhood 104,586 15,44%
    THE NEIGHBORHOOD SHAPES
    PROPERTY PRICE BY ~60%!
    2
    1 3
    HOUSING PRICE 4

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  52. 52
    Global features importance
    2
    1 3
    HOUSING PRICE 4

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  53. 53
    Global features importance
    THE NEIGHBORHOOD IS VERY
    IMPORTANT FOR THE PROPERTY PRICE
    2
    1 3
    HOUSING PRICE 4

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  54. Result
    54
    De Nadai, Marco and Bruno Lepri. "The economic value of neighborhoods: Predicting real estate
    prices from the urban environment" IEEE DSAA, 2018.
    Neighborhood features are
    very correlated
    with housing price
    2
    1 3
    HOUSING PRICE 4

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  55. Crime
    Q: Can we describe how the physical characteristics might
    influence crime?
    4

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  56. What drives crime?
    There are many theories
    CRIMINOLOGY
    • Lack of cooperation and trust
    URBAN PLANNING
    • Lack of informal surveillance:
    (guardianship by ordinary citizen, not
    just the police)
    56
    2
    1 3
    CRIME 4

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  57. Limits
    • Mobility of people is not considered
    • The built environment?
    • Usually tested in one city
    Q: Can we study multiple factors in
    multiple cities to understand crime?
    57
    2
    1 3
    CRIME 4

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  58. 58
    2
    1 3
    CRIME 4
    SOCIO-ECONOMIC
    Our model
    • Socio-economic conditions (CRIMINOLOGY)
    • Economic deprivation
    • Ethnic heterogeneity
    • Residential instability

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  59. 59
    2
    1 3
    CRIME 4
    Our model
    • Socio-economic conditions (CRIMINOLOGY)
    • The built environment (URBAN PLANNING)
    • Land use mix
    • Small blocks
    • […]
    BUILT
    ENVIRONMENT

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  60. 60
    2
    1 3
    CRIME 4
    Our model
    • Socio-economic conditions (CRIMINOLOGY)
    • The built environment (URBAN PLANNING)
    • Mobility of people
    MOBILITY
    Jiang, Shan, et al. "The TimeGeo modeling framework for urban mobility without
    travel surveys." Proceedings of the National Academy of Sciences 113.37 (2016)

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  61. 61
    2
    1 3
    CRIME 4
    Our model
    • Socio-economic conditions (CRIMINOLOGY)
    • The built environment (URBAN PLANNING)
    • Mobility of people
    • Tested for Bogotá, Boston, Chicago, Los Angeles

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  62. Describe crime
    62
    Socio-economic
    Built environment
    Descriptive
    model
    CRIME NUMBER
    For each neighborhood
    2
    1 3
    CRIME 4
    Mobility

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  63. 63
    Leroux et al. "Estimation of disease rates in small areas: a new mixed model for spatial dependence."
    Statistical models in epidemiology, the environment, and clinical trials.
    log %
    = (
    vwi
    [
    v
    v
    + CAR process
    Auto-correlation matrix
    Features
    (e.g. land use mix)
    Crime
    in a district
    (ground truth)
    Bayesian Poisson model
    2
    1 3
    CRIME 4

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  64. Results (MdAPE errors)
    64
    Model Bogota Boston Los Angeles
    Socio-economic 44% 43% 22%
    Built environment 24% 31% 22%
    Mobility 37% 40% 21%
    2
    1 3
    CRIME 4

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  65. Results (MdAPE errors)
    65
    Model Bogota Boston Los Angeles
    Socio-economic 44% 43% 22%
    Built environment 24% 31% 22%
    Mobility 37% 40% 21%
    Full model 19% 38% 15%
    SOCIO-ECONOMIC + BUILT ENVIRONMENT + MOBILITY
    2
    1 3
    CRIME 4

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  66. 66
    Small blocks
    Just an example…
    2
    1 3
    CRIME 4
    Built environment - Discrepancies

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  67. BOSTON
    BOGOTA
    67
    Just an example…
    2
    1 3
    CRIME 4
    Built environment - Discrepancies

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  68. BOSTON
    BOGOTA
    68
    THE BUILT ENVIRONMENT IS NOT ENOUGH
    Just an example…
    2
    1 3
    CRIME 4
    Built environment - Discrepancies

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  69. 69
    How can we describe crime?
    Socio-economic
    characteristics
    Built environment Mobility
    ✓ Precise data ✓ Availability
    ✓ Unbiased
    (population)
    ✗ Rarely updated
    ✗ Availability
    ✗ Bias over OSM volunteers ✗ Availability
    2
    1 3
    CRIME 4

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  70. 70
    How can we describe crime?
    Socio-economic
    characteristics
    Built environment Mobility
    ALL COMPONENTS TOGETHER
    BETTER DESCRIBE CRIME
    THEORY HAS DISCREPANCIES
    OVER DIFFERENT CITIES
    2
    1 3
    CRIME 4

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  71. 71
    Research themes
    Urban
    description
    1 4
    2 3
    Urban
    perception
    Housing price Crime

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  72. 72
    Research themes
    Urban
    description
    1 4
    2 3
    Urban
    perception
    Housing price Crime
    AUTOMATICALLY COLLECTED
    DATA
    URBAN SCIENCE AT SCALE

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  73. Why does it matter?

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  74. Why does it matter?
    74
    • DATA MINING
    • Inexpensive way to understand urban mechanisms;
    • New stimulus to social research;
    • Responsive predictions without historical data
    • Deep understanding of city life through multi-modal data
    • Studying cities means studying people
    • Gentrification?

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  75. Some limits
    75
    • Theories/models <-> domain adaptation
    • Timely predictions
    • Data driven results <-> decisions

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  76. 76
    In the (next) future
    DATA DRIVEN APPROACH: let the data speak
    STREET VIEW
    IMAGERY
    AERIAL
    IMAGERY
    + NEIGHBORHOOD
    OUTCOMES
    (CRIME,
    VITALITY…)

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  77. 77
    In the (next) future
    GANs FOR URBAN PLANNING (with Yahui Liu)
    CRIME
    VITALITY
    HOUSING PRICE
    PREDICT
    GENERATE?
    NEIGHBORHOOD
    OUTCOMES
    AERIAL + STREET VIEW
    IMAGERY

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  78. 78
    1. De Nadai, M., Staiano, J., Larcher, R., Sebe, N., Quercia, D., & Lepri, B. The death and life of great Italian
    cities: a mobile phone data perspective. WWW 2016.
    2. De Nadai, M., Vieriu, R. L., Zen, G., Dragicevic, S., Naik, N., Caraviello, M., ... & Lepri, B. (2016, October).
    Are safer looking neighborhoods more lively?: A multimodal investigation into urban life. ACM MM
    2016.
    3. De Nadai, M., & Lepri, B. The economic value of neighborhoods: Predicting real estate prices from the
    urban environment. IEEE DSAA 2018.
    4. De Nadai, M., & Lepri, B. (2018, October). Socio-economic, built environment, and mobility condi-
    tions associated with crime: A study of multiple cities. Under submission to Nature Human
    Behaviour, 2019.
    The topics of this thesis

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  79. 79
    5. Barlacchi, Gianni, et al. "A multi-source dataset of urban life in the city of Milan and the Province of
    Trentino." Nature Scientific Data 2, 2015.
    6. Centellegher, Simone, et al. "The Mobile Territorial Lab: a multilayered and dynamic view on parents’
    daily lives." EPJ Data Science 5.1, 2016.
    7. Mamei, Marco, et al. "Is social capital associated with synchronization in human communication? An
    analysis of Italian call records and measures of civic engagement." EPJ Data Science 7.1, 2018.
    8. De Nadai, Marco, et al. "Apps, Places and People: strategies, limitations and trade-offs in the physical
    and digital worlds." under review in Nature Scientific Reports, 2019.
    9. Strano, Emanuele, et al. "Precise mapping, density and spatial structure of all hu- man settlements on
    earth», under submission for Nature Communications, 2019.
    10. Liu, Yahui, et al. "Gesture-to-gesture translation in the wild via category-independent con- ditional
    maps", under review in ACM MM, 2019.
    Other topics I had the chance to explore

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  80. STEFAN
    DRAGICEVIC
    LETOUZE’
    EMMANUEL
    DANIELE QUERCIA
    MARTA C.
    GONZALEZ
    CESAR A.
    HIDALGO
    JACOPO STAIANO
    NICU SEBE
    BRUNO LEPRI
    ROBERTO
    LARCHER
    SANDY PENTLAND
    GLORIA ZEN
    XU YANYAN
    RADU L. VIERIU
    NIKHIL NAIK THANKS

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