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731 results on '"Wang, Liangzhu"'

1. Toward a Better Understanding of Fourier Neural Operators from a Spectral Perspective

Author

Qin, Shaoxiang, Lyu, Fuyuan, Peng, Wenhui, Geng, Dingyang, Wang, Ju, Tang, Xing, Leroyer, Sylvie, Gao, Naiping, Liu, Xue, and Wang, Liangzhu Leon

Subjects
Computer Science - Machine Learning
Abstract

In solving partial differential equations (PDEs), Fourier Neural Operators (FNOs) have exhibited notable effectiveness. However, FNO is observed to be ineffective with large Fourier kernels that parameterize more frequencies. Current solutions rely on setting small kernels, restricting FNO's ability to capture complex PDE data in real-world applications. This paper offers empirical insights into FNO's difficulty with large kernels through spectral analysis: FNO exhibits a unique Fourier parameterization bias, excelling at learning dominant frequencies in target data while struggling with non-dominant frequencies. To mitigate such a bias, we propose SpecB-FNO to enhance the capture of non-dominant frequencies by adopting additional residual modules to learn from the previous ones' prediction residuals iteratively. By effectively utilizing large Fourier kernels, SpecB-FNO achieves better prediction accuracy on diverse PDE applications, with an average improvement of 50%.

Published
2024

2. Typical and extreme weather datasets for studying the resilience of buildings to climate change and heatwaves

Author

Machard, Anaïs, Salvati, Agnese, P. Tootkaboni, Mamak, Gaur, Abhishek, Zou, Jiwei, Wang, Liangzhu Leon, Baba, Fuad, Ge, Hua, Bre, Facundo, Bozonnet, Emmanuel, Corrado, Vincenzo, Luo, Xuan, Levinson, Ronnen, Lee, Sang Hoon, Hong, Tianzhen, Salles Olinger, Marcello, Machado, Rayner Maurício E Silva, da Guarda, Emeli Lalesca Aparecida, Veiga, Rodolfo Kirch, Lamberts, Roberto, Afshari, Afshin, Ramon, Delphine, Ngoc Dung Ngo, Hoang, Sengupta, Abantika, Breesch, Hilde, Heijmans, Nicolas, Deltour, Jade, Kuborn, Xavier, Sayadi, Sana, Qian, Bin, Zhang, Chen, Rahif, Ramin, Attia, Shady, Stern, Philipp, and Holzer, Peter

Subjects
Earth Sciences, Atmospheric Sciences, Climate-Related Exposures and Conditions, Climate Change, Climate Action, Sustainable Cities and Communities
Abstract

We present unprecedented datasets of current and future projected weather files for building simulations in 15 major cities distributed across 10 climate zones worldwide. The datasets include ambient air temperature, relative humidity, atmospheric pressure, direct and diffuse solar irradiance, and wind speed at hourly resolution, which are essential climate elements needed to undertake building simulations. The datasets contain typical and extreme weather years in the EnergyPlus weather file (EPW) format and multiyear projections in comma-separated value (CSV) format for three periods: historical (2001-2020), future mid-term (2041-2060), and future long-term (2081-2100). The datasets were generated from projections of one regional climate model, which were bias-corrected using multiyear observational data for each city. The methodology used makes the datasets among the first to incorporate complex changes in the future climate for the frequency, duration, and magnitude of extreme temperatures. These datasets, created within the IEA EBC Annex 80 "Resilient Cooling for Buildings", are ready to be used for different types of building adaptation and resilience studies to climate change and heatwaves.

Published
2024

3. Fourier neural operator for real-time simulation of 3D dynamic urban microclimate

Author

Peng, Wenhui, Qin, Shaoxiang, Yang, Senwen, Wang, Jianchun, Liu, Xue, and Wang, Liangzhu Leon

Subjects
Computer Science - Machine Learning, Mathematics - Numerical Analysis, Physics - Fluid Dynamics
Abstract

Global urbanization has underscored the significance of urban microclimates for human comfort, health, and building/urban energy efficiency. They profoundly influence building design and urban planning as major environmental impacts. Understanding local microclimates is essential for cities to prepare for climate change and effectively implement resilience measures. However, analyzing urban microclimates requires considering a complex array of outdoor parameters within computational domains at the city scale over a longer period than indoors. As a result, numerical methods like Computational Fluid Dynamics (CFD) become computationally expensive when evaluating the impact of urban microclimates. The rise of deep learning techniques has opened new opportunities for accelerating the modeling of complex non-linear interactions and system dynamics. Recently, the Fourier Neural Operator (FNO) has been shown to be very promising in accelerating solving the Partial Differential Equations (PDEs) and modeling fluid dynamic systems. In this work, we apply the FNO network for real-time three-dimensional (3D) urban wind field simulation. The training and testing data are generated from CFD simulation of the urban area, based on the semi-Lagrangian approach and fractional stepping method to simulate urban microclimate features for modeling large-scale urban problems. Numerical experiments show that the FNO model can accurately reconstruct the instantaneous spatial velocity field. We further evaluate the trained FNO model on unseen data with different wind directions, and the results show that the FNO model can generalize well on different wind directions. More importantly, the FNO approach can make predictions within milliseconds on the graphics processing unit, making real-time simulation of 3D dynamic urban microclimate possible.

Published
2023

11. Evaluating and Mapping Indoor Thermal Risk on Older People in Long-Term Care Buildings Under Urban Microclimate Impacts

Author

Ji, Lili, Shu, Chang, Laouadi, Abdelaziz, Ge, Hua, Zmeureanu, Radu, Gaur, Abhishek, Lacasse, Michael, Wang, Liangzhu Leon, Förstner, Ulrich, Series Editor, Rulkens, Wim H., Series Editor, Wang, Liangzhu Leon, editor, Ge, Hua, editor, Zhai, Zhiqiang John, editor, Qi, Dahai, editor, Ouf, Mohamed, editor, Sun, Chanjuan, editor, and Wang, Dengjia, editor

Published
2023
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12. A Review of Recent Progress on Urban Microclimate Research

Author

Yang, Senwen, Wang, Liangzhu Leon, Stathopoulos, Ted, Förstner, Ulrich, Series Editor, Rulkens, Wim H., Series Editor, Wang, Liangzhu Leon, editor, Ge, Hua, editor, Zhai, Zhiqiang John, editor, Qi, Dahai, editor, Ouf, Mohamed, editor, Sun, Chanjuan, editor, and Wang, Dengjia, editor

Published
2023
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15. Quantification of Building Thermal Resilience Against Heatwaves

Author

Ji, Lili, Shu, Chang, Laouadi, Abdelaziz, Ge, Hua, Zmeureanu, Radu, Lacasse, Michael, Wang, Liangzhu Leon, Förstner, Ulrich, Series Editor, Rulkens, Wim H., Series Editor, Wang, Liangzhu Leon, editor, Ge, Hua, editor, Zhai, Zhiqiang John, editor, Qi, Dahai, editor, Ouf, Mohamed, editor, Sun, Chanjuan, editor, and Wang, Dengjia, editor

Published
2023
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16. Comparing Multiple Overheating Assessment Metrics Using Measured Data

Author

Shu, Chang, Xie, Zihan, Ji, Lili, Baril, Daniel, Wang, Lin, Bai, Xuechen, Yang, Senwen, Ge, Hua, Zmeureanu, Radu, Lacasse, Michael, Laouadi, Abdelaziz, Gaur, Abhishek, Wang, Liangzhu Leon, Förstner, Ulrich, Series Editor, Rulkens, Wim H., Series Editor, Wang, Liangzhu Leon, editor, Ge, Hua, editor, Zhai, Zhiqiang John, editor, Qi, Dahai, editor, Ouf, Mohamed, editor, Sun, Chanjuan, editor, and Wang, Dengjia, editor

Published
2023
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20. Development and Testing of a Data Schema for Exchanging Information Between Urban Building Energy Models and Urban Microclimate Models

Author

Luo, Xuan, Mortezazadeh, Mohammad, Luo, Na, Albettar, Maher, Zhang, Wanni, Hong, Tianzhen, Wang, Liangzhu Leon, Förstner, Ulrich, Series Editor, Rulkens, Wim H., Series Editor, Wang, Liangzhu Leon, editor, Ge, Hua, editor, Zhai, Zhiqiang John, editor, Qi, Dahai, editor, Ouf, Mohamed, editor, Sun, Chanjuan, editor, and Wang, Dengjia, editor

Published
2023
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22. Study of Urban Building Configuration Impacts on Outdoor Thermal Comfort Under Summer Heatwave via CityFFD and CityBEM

Author

Yang, Senwen, Mortezazadeh, Mohammad, Zou, Jiwei, Katal, Ali, Leroyer, Sylvie, Wang, Liangzhu Leon, Stathopoulos, Ted, Förstner, Ulrich, Series Editor, Rulkens, Wim H., Series Editor, Wang, Liangzhu Leon, editor, Ge, Hua, editor, Zhai, Zhiqiang John, editor, Qi, Dahai, editor, Ouf, Mohamed, editor, Sun, Chanjuan, editor, and Wang, Dengjia, editor

Published
2023
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28. A data schema for exchanging information between urban building energy models and urban microclimate models in coupled simulations

Author

Luo, Na, Luo, Xuan, Mortezazadeh, Mohammad, Albettar, Maher, Zhang, Wanni, Zhan, Dongxue, Wang, Liangzhu Leon, and Hong, Tianzhen

Subjects
Built Environment and Design, Architecture, Sustainable Cities and Communities, Urban building energy modeling, Urban microclimate, Coupled simulation, CityFFD, CityBES, data model, Building
Abstract

Understanding and quantifying the interactions between urban microclimate and urban buildings is essential to improve the urban environment and building performance, especially during heatwaves. Most previous studies used tool or application specific data exchange mechanisms that cannot be generalized for other tools or applications. In this paper, we introduce a new flexible and tool-agnostic data schema to facilitate the exchange of data between urban building energy models and urban microclimate models. The JSON schema was tested using a district of 97 buildings in San Francisco and running simulations with CityBES and CityFFD as the urban building energy and microclimate modeling platforms, respectively. Compared with simulation results using the historical weather data, simulation results considering interactions between two models over a two-day heatwave event showed a 5.3°C higher average peak building facade temperature, an 8.9 °C higher average peak air node temperature, and a 19.5% higher peak cooling energy use.

Published
2022

29. Resilient cooling strategies – A critical review and qualitative assessment

Author

Zhang, Chen, Kazanci, Ongun Berk, Levinson, Ronnen, Heiselberg, Per, Olesen, Bjarne W, Chiesa, Giacomo, Sodagar, Behzad, Ai, Zhengtao, Selkowitz, Stephen, Zinzi, Michele, Mahdavi, Ardeshir, Teufl, Helene, Kolokotroni, Maria, Salvati, Agnese, Bozonnet, Emmanuel, Chtioui, Feryal, Salagnac, Patrick, Rahif, Ramin, Attia, Shady, Lemort, Vincent, Elnagar, Essam, Breesch, Hilde, Sengupta, Abantika, Wang, Liangzhu Leon, Qi, Dahai, Stern, Philipp, Yoon, Nari, Bogatu, Dragos-Ioan, Rupp, Ricardo Forgiarini, Arghand, Taha, Javed, Saqib, Akander, Jan, Hayati, Abolfazl, Cehlin, Mathias, Sayadi, Sana, Forghani, Sadegh, Zhang, Hui, Arens, Edward, and Zhang, Guoqiang

Subjects
Built Environment and Design, Architecture, Sustainable Cities and Communities, Building cooling, Resilient, Climate change, Heatwave, Power outage, Qualitative analysis, Passive cooling, Active cooling, Low-energy cooling, Critical review, Engineering, Building & Construction, Built environment and design
Abstract

The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out.

Published
2021

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