The role of complexity for digital twins of cities.

We argue that theories and methods drawn from complexity science are urgently needed to guide the development and use of digital twins for cities. The theoretical framework from complexity science takes into account both the short-term and the long-term dynamics of cities and their interactions. This is the foundation for a new approach that treats cities not as large machines or logistic systems but as mutually interwoven self-organizing phenomena, which evolve, to an extent, like living systems.

Brief Report: Early VEPs to Pattern-Reversal in Adolescents and Adults with Autism.

Autism spectrum disorder (ASD) is characterized by atypical visual perception both in the social and nonsocial domain. In order to measure a reliable visual response, visual evoked potentials were recorded during a passive pattern-reversal stimulation in adolescents and adults with and without ASD. While the present results show the same age-related changes in both autistic and non-autistic groups, they reveal a smaller P100 amplitude in the ASD group compared to controls. These results confirm that early visual responses are affected in ASD even with a simple, non social and passive stimulation and suggest that they should be considered in order to better understand higher-level processes.

[Atypical perception processing and facial emotion disorder in autism]. / Les anomalies du traitement des émotions faciales dans l'autisme : un trouble de la perception globale.

INTRODUCTION: Autistic syndrome is defined by several abnormalities, mainly affecting social interaction skills. Disorders of the processes of processing facial and emotional stimuli, and particularly avoidance of gaze, have also been reported in this disorder. Some authors have suggested that these abnormalities may be explained, or at least contributed to, by the social disorder observed in this syndrome. The aim of this study was therefore to improve the understanding of the processes involved in perception AND the representation of faces expressing emotion in subjects with autism spectrum disorders (ASDs). METHODS: Eleven children with ASDs (mean developmental age 7 years 11 months) and eleven normally developing children (mean age 7 years 9 months) took part in three experiments. The first involved overall discrimination of emotions using photographs of faces expressing six basic emotions, the second required local emotional discrimination on the basis of isolated elements of the face (photographs of eyes and mouths isolated from the rest of the face), and for the third the children were asked to create faces expressing emotions by means of a jig-saw puzzle format, using photographs of isolated elements of the face (overall representation necessitating local discrimination). RESULTS: Our findings revealed that the normally developing children had difficulties with the process of local discrimination of emotions: their performance improved when overall perception was possible. In contrast, and astonishingly, the children with ASD were more able to discriminate isolated eyes expressing emotion than the controls, but their performance declined when overall processing was required. DISCUSSION: Our results suggested that the emotional disorders observed in ASDs might be explained by greater skills in the processing of local information. This might explain the inability of children with ASDs to achieve coherent perception of their social environment and might also lead to the withdrawal that is characteristic of this disorder. These results also suggest that the gaze avoidance that is characteristic of individuals with ASDs is eliminated when eyes are presented alone. This gaze avoidance therefore seems to be related to the complexity and variability of this type of stimulus and not to the social nature of the stimulus.

Autistic spectrum disorder traits in children with attention deficit hyperactivity disorder.

BACKGROUND: Current classification systems do not allow for comorbid diagnoses of attention deficit hyperactivity disorder (ADHD) and autistic spectrum disorder (ASD). Children with ADHD are often screened for ASD during clinical assessment and when recruited to clinical trials. We predicted that children with ADHD would have more autistic traits than controls and that certain traits would be more prevalent. METHODS: The clinically referred sample consisted of 30 children with ADHD and 30 matched controls aged 9-15 years. Children were screened for ASD traits using the Social Aptitudes Scale (SAS) and the Social Communication Questionnaire (SCQ). RESULTS: We found that ASD traits were significantly higher in children with ADHD than controls. None of the children received a diagnosis of autism or ASD. However, a large proportion (28% using the SCQ and 62% using the SAS) of children with ADHD reached screening thresholds for a predictive diagnosis of ASD. Relative to controls, children with ADHD had significantly higher levels of communication and social deficits, but not repetitive behaviours. CONCLUSION: Further work is needed to establish whether autistic-like communication and social difficulties in children with ADHD are part of the broader ASD phenotype or are specific to ADHD.

The faces of development: a review of early face processing over childhood.

The understanding of the adult proficiency in recognizing and extracting information from faces is still limited despite the number of studies over the last decade. Our knowledge on the development of these capacities is even more restricted, as only a handful of such studies exist. Here we present a combined reanalysis of four ERP studies in children from 4 to 15 years of age and adults (n = 424, across the studies), which investigated face processing in implicit and explicit tasks. We restricted these analyses to what was common across studies: early ERP components and upright face processing across all four studies and the inversion effect, investigated in three of the studies. These data demonstrated that processing faces implicates very rapid neural activity, even in young children--at the P1 component--with protracted age-related change in both P1 and N170, that were sensitive to the different task demands. Inversion produced latency and amplitude effects on the P1 from the youngest group, but on N170 only starting in mid childhood. These developmental data suggest that there are functionally different sources of the P1 and N170, related to the processing of different aspects of faces.

Visual categorization during childhood: an ERP study.

Categorization is a basic means of organizing the world around us and offers a simple way to process the mass of stimuli one perceives every day. The ability to categorize appears early in infancy, and has important ramifications for the acquisition of other cognitive capacities, but little is known of its development during childhood. We studied 48 children (7-15 years of age) and 14 adults using an animal/nonanimal visual categorization task while event-related potentials (ERPs) were recorded. Three components were measured: P1, N2, and P3. Behaviorally, the children performed the task very similarly to adults, although the children took longer to make categorization responses. Decreases in latencies (N2, P3) and amplitudes (P1, N2, P3) with age indicated that categorization processes continue to develop through childhood. P1 latency did not differ between the age groups. N2 latency, which is associated with stimulus categorization, reached adult levels at 9 years and P3 latency at 11 years of age. Age-related amplitude decreases started after the maturational changes in latencies were finished.

Preliminary evidence for a theory of the fractal city.

"In this paper, we argue that the geometry of urban residential development is fractal. Both the degree to which space is filled and the rate at which it is filled follow scaling laws which imply invariance of function, and self-similarity of urban form across scale. These characteristics are captured in population density functions based on inverse power laws whose parameters are fractal dimensions. First we outline the relevant elements of the theory in terms of scaling relations and then we introduce two methods for estimating fractal dimension based on varying the size of cities and the scale at which their form is detected. Exact and statistical estimation techniques are applied to each method respectively generating dimensions which measure the extent and the rate of space filling. These methods are then applied to residential development patterns in six industrial cities in the northeastern United States...."

A strategy for generating and testing models of migration and urban growth.

"In this paper, it is argued that to identify the appropriate conditions under which the traditional gravity-type migration model should be tested, it is necessary to consider the wider demographic-economic framework in which such models play an essential part. The traditional model and attempts to make it more realistic in an ad hoc way are first sketched, and then the model is embedded in a dynamic framework based on nonlinear differential equations of the logistic kind describing the growth of population and employment. The role of the gravity model in coupling these equations is then developed." A theoretical analysis of this framework is then presented using simulation. "The simplest possible two-region case involving urban and rural regions is developed and after preliminary simulations, a more realistic version involving urban core, suburb and rural hinterland is proposed. A number of variants of this model are tested using simulation and it is concluded that in devising an appropriate test for this type of migration model, attention should be switched from spatial to temporal variation in migration using highly polarized spatial situations such as city regions." (summary in FRE, GER)

Spatial aggregation in gravity models: 4. Generalisations and large-scale applications.

"This paper is concerned with applying and extending a methodology for analysing spatial aggregation in gravity models developed in three earlier papers to a larger scale and hence more realistic example of spatial interaction than has been treated so far." Seven models are generated and applied to four levels of aggregation of the spatial interaction pattern in Edmonton, Alberta.

Spatial aggregation in gravity models: 2. One-dimensional population density models.

"This paper, the second of four, is concerned with applying a methodology for analysing the spatial aggregation problem in gravity models outlined in the first paper. The methodology is based on a consistent framework for linking measures of pattern in interaction data to the derivation and estimation of related interaction models using spatial information. In this quest, a link is forged between information in data and the parameters of an associated model.... This relationship can be formalised for the case of the continuous one-dimensional interaction model such as the population density model, and this paper is concerned with demonstrating such an application to aggregations of zones in the Reading [England] region."