269 research outputs found
Urbanization, land use, and sustainable development in China
pre-printChina's economic reforms and unprecedented growth have generated many fascinating issues for scholarly research. An understanding of urbanization and land use change in China is required for appropriate strategies and policies to facilitate future sustainable development. This paper reviews the literature on urbanization, land use and sustainable development in China with a focus on land use change. We argue that land use and environmental research are embedded in the complex economic-geographical processes and multiple trajectories of development and urbanization in China. This paper highlights the important role of space-time modeling in a multi-disciplinary setting in the study of urbanization, land use and sustainable development. It also points out potential areas for future research
Data-based Polymer-Unit Fingerprint (PUFp): A Newly Accessible Expression of Polymer Organic Semiconductors for Machine Learning
In the process of finding high-performance organic semiconductors (OSCs), it
is of paramount importance in material development to identify important
functional units that play key roles in material performance and subsequently
establish substructure-property relationships. Herein, we describe a
polymer-unit fingerprint (PUFp) generation framework. Machine learning (ML)
models can be used to determine structure-mobility relationships by using PUFp
information as structural input with 678 pieces of collected OSC data. A
polymer-unit library consisting of 445 units is constructed, and the key
polymer units for the mobility of OSCs are identified. By investigating the
combinations of polymer units with mobility performance, a scheme for designing
polymer OSC materials by combining ML approaches and PUFp information is
proposed to not only passively predict OSC mobility but also actively provide
structural guidance for new high-mobility OSC material design. The proposed
scheme demonstrates the ability to screen new materials through pre-evaluation
and classification ML steps and is an alternative methodology for applying ML
in new high-mobility OSC discovery.Comment: 42 pages, 13 figure
Sequencing-enabled Hierarchical Cooperative CAV On-ramp Merging Control with Enhanced Stability and Feasibility
This paper develops a sequencing-enabled hierarchical connected automated
vehicle (CAV) cooperative on-ramp merging control framework. The proposed
framework consists of a two-layer design: the upper level control sequences the
vehicles to harmonize the traffic density across mainline and on-ramp segments
while enhancing lower-level control efficiency through a mixed-integer linear
programming formulation. Subsequently, the lower-level control employs a
longitudinal distributed model predictive control (MPC) supplemented by a
virtual car-following (CF) concept to ensure asymptotic local stability, l_2
norm string stability, and safety. Proofs of asymptotic local stability and l_2
norm string stability are mathematically derived. Compared to other prevalent
asymptotic local-stable MPC controllers, the proposed distributed MPC
controller greatly expands the initial feasible set. Additionally, an auxiliary
lateral control is developed to maintain lane-keeping and merging smoothness
while accommodating ramp geometric curvature. To validate the proposed
framework, multiple numerical experiments are conducted. Results indicate a
notable outperformance of our upper-level controller against a distance-based
sequencing method. Furthermore, the lower-level control effectively ensures
smooth acceleration, safe merging with adequate spacing, adherence to proven
longitudinal local and string stability, and rapid regulation of lateral
deviations
Integrating urban digital twins with cloud-based geospatial dashboards for coastal resilience planning: A case study in Florida
Coastal communities are confronted with a growing incidence of
climate-induced flooding, necessitating adaptation measures for resilience. In
this paper, we introduce a framework that integrates an urban digital twin with
a geospatial dashboard to allow visualization of the vulnerabilities within
critical infrastructure across a range of spatial and temporal scales. The
synergy between these two technologies fosters heightened community awareness
about increased flood risks to establish a unified understanding, the
foundation for collective decision-making in adaptation plans. The paper also
elucidates ethical considerations while developing the platform, including
ensuring accessibility, promoting transparency and equity, and safeguarding
individual privacy
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