基于生态效应的城市绿色空间体系构建--以西安国际港务区绿带公园为例

城市绿色空间是城市生态的载体,城市绿色空间系统的建设尤为重要。城市绿色空间系统不仅为城市居民提供了休闲娱乐的场所,还有助于改善空气质量、调节城市微气候、保护生物多样性等。然而,随着城市化进程的加速,城市绿色空间系统的建设面临诸多挑战,其中之一便是生态效应与城市绿色空间体系的构建。正因如此,将城市与绿色自然空间融合已成为现代城市空间建设的普遍选择。通过西安国际港务区新建绿带公园为例,探讨分析在城市绿色空间建设过程中所采用的区域生态构建、功能补充和多尺度协同实践模式,以期为城市绿色空间体系的构建提供理论支持和实践参考。

Frequency-domain elastic full-waveform multiscale inversion method based on dual-level parallelism

The complexity of an elastic wavefield increases the nonlinearity of inversion, To some extent, multiscale inversion decreases the nonlinearity of inversion and prevents it from falling into local extremes. A multiscale strategy based on the simultaneous use of frequency groups and layer stripping method based on damped wave field improves the stability of inversion. A dual-level parallel algorithm is then used to decrease the computational cost and improve practicability. The seismic wave modeling of a single frequency and inversion in a frequency group are computed in parallel by multiple nodes based on multifrontal massively parallel sparse direct solver and MPI. Numerical tests using an overthrust model show that the proposed inversion algorithm can effectively improve the stability and accuracy of inversion by selecting the appropriate inversion frequency and damping factor in low- frequency seismic data.

基于U-Net的COVID-19病灶医学影像ZMINet分割模型

针对COVID-19病灶医学影像边缘模糊及小病灶丢失的问题,基于多尺度多层级特征集成与多分支交互式学习策略对U-Net进行改进,提出一种基于U-Net的COVID-19病灶医学影像ZMINet分割模型。原图被缩放至多个尺度输入编码器;利用SIU-AIM模块多分支交互式地逐层学习融合层内与层间的多尺度关键特征,并将特征传入由SIM组成的解码器之对应层;SIM利用交互式学习策略以获取更丰富的多尺度信息表征,并自下而上集成多层特征;使用UAL作为损失函数指导模型输出更清晰的预测结果。在公开数据集上的对比实验表明,ZMINet分割模型在Dice、精确率、特异性和平均绝对误差等指标分别达到了79.2%、81.8%、96.8%和6.3%,与其他算法相比其性能得到了明显的提升。