The discourse, governance and configurations of polycentricity in transitional China: a case study of Tianjin

Polycentricity has been identified as a prominent feature of modern landscapes as well as a buzzword in spatial planning at a range of scales worldwide. Since the Reform and Opening-up Policy in 1978, major cities in China have experienced significant polycentric transition manifested by their new spatial policy framework and reshaped spatial structure. The polycentric transformation has provoked academics’ interests on structural and performance analysis in quantitative ways recently. However, little research investigates the nature of (re)formation and implementation of polycentric development policies in Chinese cities from a processual and critical perspective. This research interprets the underlying meanings and rationality of polycentric development strategy in planning discourse and explains how concrete centres within the polycentric system are created, governed and materialized to facilitate the implementation of polycentric policies in the special context of political system, spatial planning system and socio-economic conditions in China. Referring to existing literature of polycentricity and theories of urban space, this research develops a novel theoretical framework, which holds that polycentricity is produced by the articulation of state power, planning profession and produced space. The research is founded on an embedded case study of Tianjin based on empirical data derived from interviews with stakeholders and secondary data. Through a discourse analysis of four Tianjin City Master Plans, discourses of ‘polycentric urban settlements’, ‘functional polycentricity’, ‘polycentric growth nodes’ and ‘nested polycentricity’ are identified, which are deployed in different ways with variegated composition of spatial elements. Moreover, rather than being mere technocratic practice, the production and legitimation of distinct discourses is essentially an articulation of multi-scalar power involving various stakeholders, which is disguised and justified by the planning profession. The findings demonstrate that polycentricity is a malleable concept and its fluidity creates space to accommodate consensus or to allow the play of contested interests and policy experiments. Based on that, this research further selects centres in Tianjin Binhai New Area Core Zone, Wuqing District and Dongli District as embedded cases to explore how the polycentric development policy is implemented in practice. The empirical findings from local perspective show that these centres are created or formed according to different contexts and logics, and they are consolidated by employment of a portfolio of tools and instruments such as new planning and urban design, establishment of financial and development corporations, exclusive preferential policies, manipulation of public sector, land development and institutional innovation. Correspondingly, these centres have experienced distinct development trajectories and shown different spatial outcomes from the perspectives of urban form, functional composition, and spatial identity. It is suggested that significant gaps and contradictions exist between spatial visions and actual development, which poses challenges for sustainable development

Investigating impacts of environmental factors on the cycling behavior of bicycle-sharing users

As it is widely accepted, cycling tends to produce health benefits and reduce air pollution. Policymakers encourage people to use bikes by improving cycling facilities as well as developing bicycle-sharing systems (BSS). It is increasingly interesting to investigate how environmental factors influence the cycling behavior of users of bicycle-sharing systems, as users of bicycle-sharing systems tend to be different from regular cyclists. Although earlier studies have examined effects of safety and convenience on the cycling behavior of regular riders, they rarely explored effects of safety and convenience on the cycling behavior of BSS riders. Therefore, in this study, we aimed to investigate how road safety, convenience, and public safety affect the cycling behavior of BSS riders by controlling for other environmental factors. Specifically, in this study, we investigated the impacts of environmental characteristics, including population density, employment density, land use mix, accessibility to point-of-interests (schools, shops, parks and gyms), road infrastructure, public transit accessibility, road safety, convenience, and public safety on the usage of BSS. Additionally, for a more accurate measure of public transit accessibility, road safety, convenience, and public safety, we used spatiotemporally varying measurements instead of spatially varying measurements, which have been widely used in earlier studies. We conducted an empirical investigation in Chicago with cycling data from a BSS called Divvy. In this study, we particularly attempted to answer the following questions: (1) how traffic accidents and congestion influence the usage of BSS; (2) how violent crime influences the usage of BSS; and (3) how public transit accessibility influences the usage of BSS. Moreover, we tried to offer implications for policies aiming to increase the usage of BSS or for the site selection of new docking stations. Empirical results demonstrate that density of bicycle lanes, public transit accessibility, and public safety influence the usage of BSS, which provides answers for our research questions. Empirical results also suggest policy implications that improving bicycle facilities and reducing the rate of violent crime rates tend to increase the usage of BSS. Moreover, some environmental factors could be considered in selecting a site for a new docking station

Piecewise deterministic Markov process for condition-based imperfect maintenance models

In this paper, a condition-based imperfect maintenance model based on piecewise deterministic Markov process (PDMP) is constructed. The degradation of the system includes two types: natural degradation and random shocks. The natural degradation is deterministic and can be nonlinear. The damage increment caused by a random shock follows a certain distribution, and its parameters are related to the degradation state. Maintenance methods include corrective maintenance and imperfect maintenance. Imperfect maintenance reduces the degradation degree of the system according to a random proportion. The maintenance action is delayed, and the system will suffer natural degradations and random shocks while waiting for maintenance. At each inspection time, the decision-maker needs to make a choice among planning no maintenance, imperfect maintenance and perfect maintenance, so as to minimize the total discounted cost of the system. The impulse optimal control theory of PDMP is used to determine the optimal maintenance strategy. A numerical study dealing with component coating maintenance problem is presented. Relationship with optimal threshold strategy is discussed. Sensitivity analyses on the influences of discount factor, observation interval and maintenance cost to the discounted cost and optimal actions are presented.Comment: 34 pages, 28 figure

The (re)making of polycentricity in China’s planning discourse: the case of Tianjin

Polycentricity is promoted as an ideal urban form to achieve sustainable and balanced development, and it has been widely adopted by planners in China, especially in large cities. However, the rhetoric about polycentricity has rarely been interrogated in planning research in terms of scales, contextuality, power and rationality. To fill this gap, we carried out a Foucauldian discourse analysis in our research to interpret the nature of polycentric practice in City Master Plans, using Tianjin as a case study. Through an analysis of how the discourse of polycentricity is being deployed in planning documents, we develop two principal arguments in this article. First, the conceptual substance of polycentricity evolved alongside the urban transition process in China, and its discursive practice involved multiple scales and spatial elements. Secondly, rather than being mere technocratic practice, the production and legitimation of distinct discourses of polycentricity is an articulation of multi‐scalar power involving various stakeholders, which is disguised and justified by the planning profession

City-regional governance under state entrepreneurialism in China

Facing de-globalisation, changing international politics, climate changes and new smart technologies in the post-pandemic era, city-regions become important spaces for economic, social and environmental governance. In China, this new city-regional form of governance is created under state entrepreneurialism, which means the state uses entrepreneurial endeavours to achieve its strategic vision and intention. The processes of city-region building include centralising the spatial planning system, inventing new spatial discourses, representing regional imaginaries and restructuring the state towards ecological goals. Instead of market-driven regional dynamics or redistributive politics, China’s city-regional governance demonstrates the role of the multi-scalar state in constructing and implementing economic, social and environmental policies at a regional scale

Environmental city-regionalism in China: War against air pollution in the Beijing-Tianjin-Hebei Region

The state remains central in contemporary environmental politics and policies, although environmental governance increasingly involves neoliberal and non-state mechanisms. Environmental management in China holds features of an ‘environmental state’ and has been undergoing continuous restructuring, manifested by a recent city-regionalism turn. Informed by the theories of eco-state restructuring (ESR) and eco-scalar fix, this paper investigates air pollution management in the Beijing-Tianjin-Hebei Region by tracing the practices of environmental and territorial governance over the past decades. Through the analysis of parameters of the eco-state, this paper conceptualises the air pollution governance in China into three phases, namely pollutants emission control (the 1990s2005), campaign-style regional governance (2006-2012) and city regionalism in air quality governance (2013 onwards). We find that the central state plays proactive but different roles in each phase, characterised by state strategic selectivity, adjustments of state apparatus, deployment of a set of policy instruments, and enhanced state capacities for monitoring, control, and legitimation. In this context, the city-regional level has become the key scale at which environmental regulations are targeted and the economic and environmental realms are being (re)formed. This state-led eco-scalar fix process to cope with urgent environmental issues explains the underlying rationality of building up the Beijing-Tianjin-Hebei Region as a new national strategic project

Remodeling Pearson's Correlation for Functional Brain Network Estimation and Autism Spectrum Disorder Identification

Functional brain network (FBN) has been becoming an increasingly important way to model the statistical dependence among neural time courses of brain, and provides effective imaging biomarkers for diagnosis of some neurological or psychological disorders. Currently, Pearson's Correlation (PC) is the simplest and most widely-used method in constructing FBNs. Despite its advantages in statistical meaning and calculated performance, the PC tends to result in a FBN with dense connections. Therefore, in practice, the PC-based FBN needs to be sparsified by removing weak (potential noisy) connections. However, such a scheme depends on a hard-threshold without enough flexibility. Different from this traditional strategy, in this paper, we propose a new approach for estimating FBNs by remodeling PC as an optimization problem, which provides a way to incorporate biological/physical priors into the FBNs. In particular, we introduce an L1-norm regularizer into the optimization model for obtaining a sparse solution. Compared with the hard-threshold scheme, the proposed framework gives an elegant mathematical formulation for sparsifying PC-based networks. More importantly, it provides a platform to encode other biological/physical priors into the PC-based FBNs. To further illustrate the flexibility of the proposed method, we extend the model to a weighted counterpart for learning both sparse and scale-free networks, and then conduct experiments to identify autism spectrum disorders (ASD) from normal controls (NC) based on the constructed FBNs. Consequently, we achieved an 81.52% classification accuracy which outperforms the baseline and state-of-the-art methods

First attempt to build realistic driving scenes using video-to-video synthesis in OpenDS framework

Existing programmable simulators enable researchers to customize different driving scenarios to conduct in-lab automotive driver simulations. However, software-based simulators for cognitive research generate and maintain their scenes with the support of 3D engines, which may affect users' experiences to a certain degree since they are not sufficiently realistic. Now, a critical issue is the question of how to build scenes into real-world ones. In this paper, we introduce the first step in utilizing video-to-video synthesis, which is a deep learning approach, in OpenDS framework, which is an open-source driving simulator software, to present simulated scenes as realistically as possible. Off-line evaluations demonstrated promising results from our study, and our future work will focus on how to merge them appropriately to build a close-to-reality, real-time driving simulator