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Collaborating Authors

 Luo, Peng


Interpreting core forms of urban morphology linked to urban functions with explainable graph neural network

arXiv.org Artificial Intelligence

Understanding the high-order relationship between urban form and function is essential for modeling the underlying mechanisms of sustainable urban systems. Nevertheless, it is challenging to establish an accurate data representation for complex urban forms that are readily explicable in human terms. This study proposed the concept of core urban morphology representation and developed an explainable deep learning framework for explicably symbolizing complex urban forms into the novel representation, which we call CoMo. By interpretating the well-trained deep learning model with a stable weighted F1-score of 89.14%, CoMo presents a promising approach for revealing links between urban function and urban form in terms of core urban morphology representation. Using Boston as a study area, we analyzed the core urban forms at the individual-building, block, and neighborhood level that are important to corresponding urban functions. The residential core forms follow a gradual morphological pattern along the urban spine, which is consistent with a center-urban-suburban transition. Furthermore, we prove that urban morphology directly affects land use efficiency, which has a significantly strong correlation with the location (R2=0.721, p<0.001). Overall, CoMo can explicably symbolize urban forms, provide evidence for the classic urban location theory, and offer mechanistic insights for digital twins.


GeoConformal prediction: a model-agnostic framework of measuring the uncertainty of spatial prediction

arXiv.org Machine Learning

Spatial prediction is a fundamental task in geography. In recent years, with advances in geospatial artificial intelligence (GeoAI), numerous models have been developed to improve the accuracy of geographic variable predictions. Beyond achieving higher accuracy, it is equally important to obtain predictions with uncertainty measures to enhance model credibility and support responsible spatial prediction. Although geostatistic methods like Kriging offer some level of uncertainty assessment, such as Kriging variance, these measurements are not always accurate and lack general applicability to other spatial models. To address this issue, we propose a model-agnostic uncertainty assessment method called GeoConformal Prediction, which incorporates geographical weighting into conformal prediction. We applied it to two classic spatial prediction cases, spatial regression and spatial interpolation, to evaluate its reliability. First, in the spatial regression case, we used XGBoost to predict housing prices, followed by GeoConformal to calculate uncertainty. Our results show that GeoConformal achieved a coverage rate of 93.67%, while Bootstrap methods only reached a maximum coverage of 81.00% after 2000 runs. Next, we applied GeoConformal to spatial interpolation models. We found that the uncertainty obtained from GeoConformal aligned closely with the variance in Kriging. Finally, using GeoConformal, we analyzed the sources of uncertainty in spatial prediction. We found that explicitly including local features in AI models can significantly reduce prediction uncertainty, especially in areas with strong local dependence. Our findings suggest that GeoConformal holds potential not only for geographic knowledge discovery but also for guiding the design of future GeoAI models, paving the way for more reliable and interpretable spatial prediction frameworks.


Genetic Quantization-Aware Approximation for Non-Linear Operations in Transformers

arXiv.org Artificial Intelligence

The performance greatly benefits from the self-attention mechanism in Transformers, which could capture long-range dependencies Non-linear functions are prevalent in Transformers and their lightweight well, but with a substantial overhead in computation variants, incurring substantial and frequently underestimated and memory. Extensive research has been conducted to facilitate the hardware costs. Previous state-of-the-art works optimize deployment of Transformers on edge devices. Techniques like lightweight these operations by piece-wise linear approximation and store the structure integrating convolution and linear attention [4, 5] parameters in look-up tables (LUT), but most of them require unfriendly emerge, while quantization [6-8] and run-time pruning [9] has become high-precision arithmetics such as FP/INT 32 and lack consideration favored approaches to further reduced the hardware burden. of integer-only INT quantization. This paper proposed a However, the optimization of non-linear operations is frequently genetic LUT-Approximation algorithm namely GQA-LUT that can neglected in Transformer-based models which can be costly due to automatically determine the parameters with quantization awareness.


Uncover the nature of overlapping community in cities

arXiv.org Artificial Intelligence

Urban spaces, though often perceived as discrete communities, are shared by various functional and social groups. Our study introduces a graph-based physics-aware deep learning framework, illuminating the intricate overlapping nature inherent in urban communities. Through analysis of individual mobile phone positioning data at Twin Cities metro area (TCMA) in Minnesota, USA, our findings reveal that 95.7 % of urban functional complexity stems from the overlapping structure of communities during weekdays. Significantly, our research not only quantifies these overlaps but also reveals their compelling correlations with income and racial indicators, unraveling the complex segregation patterns in U.S. cities. As the first to elucidate the overlapping nature of urban communities, this work offers a unique geospatial perspective on looking at urban structures, highlighting the nuanced interplay of socioeconomic dynamics within cities.