The challenges of integrating explainable artificial intelligence into GeoAI

Although explainable artificial intelligence (XAI) promises considerable progress in glassboxing deep learning models, there are challenges in applying XAI to geospatial artificial intelligence (GeoAI), specifically geospatial deep neural networks (DNNs). We summarize these as three major challenges, related generally to XAI computation, to GeoAI and geographic data handling, and to geosocial issues. XAI computation includes the difficulty of selecting reference data/models and the shortcomings of attributing explanatory power to gradients, as well as the difficulty in accommodating geographic scale, geovisualization, and underlying geographic data structures. Geosocial challenges encompass the limitations of knowledge scope—semantics and ontologies—in the explanation of GeoAI as well as the lack of integrating non-technical aspects in XAI, including processes that are not amenable to XAI. We illustrate these issues with a land use classification case study.     

Weighted total least squares: necessary and sufficient conditions, fixed and random parameters

A standard errors-in-variables (EIV) model refers to a Gauss–Markov model with an uncertain model matrix from a geodetic perspective. Least squares within the EIV model is usually called the total least squares (TLS) technique because of its symmetrical adjustment. However, the solutions and computational advantages of the weighted TLS problem with a general weight matrix (WTLS) are mostly unknown. In this study, the WTLS problem was solved using three different approaches: iterative methods based on the normal equation, the iteratively linearized Gauss–Helmert model with algebraic Jacobian matrices, and numerical analysis. Furthermore, sufficient conditions for WTLS optimization were investigated systematically as proposed solutions yield only necessary conditions for optimality. A WTLS solution was considered to treat random parameters within the EIV model. Last, applications to test these novel algorithms are presented.     

地球参考框架的建立和维持

详细总结了ITRF等参考框架的原理,分析了其优缺点和特性并分析了不同地球参考框架的区别。本文在协议研究的基础上,结合我国实际,提出了建立我国新一代地球参考系统的若干建议。     

塔北隆起古生代构造样式和构造反演

塔北隆起是塔里木盆地的主要含油气区,笔者利用地震剖面解释和平衡剖面技术对塔北隆起构造变形和构造演化进行了研究.塔北隆起构造变形存在明显的构造差异,西部英买力地区主要发育盖层滑脱式逆冲断层褶皱和"y"型压扭断层,而其东部主要发育基底卷入式逆断层及断层传播褶皱和反冲断层构造.造成塔北隆起东、西构造样式差异的机理主要有两点:一是东部地区对震旦纪一早奥陶世正断层在后期挤压作用下反转,二是英买力地区中寒武统盐层的发育.塔北隆起地区古生代构造演化也存在着一定的差异,塔北隆起东部震旦纪一早奥陶世发育大型正断层构造,而英买力地区为稳定碳酸盐岩台地;晚奥陶世至泥盆纪,塔北隆起东部牙哈断层发生反转,轮台凸起隆升,而英买力地区位于隆起的斜坡部位;石炭纪至二叠纪,塔北隆起东部大规模抬升,剥蚀严重,出露变质基底,英买力地区接受强烈的变形作用,主要发育盖层滑脱式逆断层和褶皱构造.     

Assessment of the Excavation-Damaged Zone in a Tall Rock Slope Using Acoustic Testing Method

During slope excavation, high stresses can become concentrated in the rock mass because of stress redistribution. Failure of the rock mass creates an excavation-damaged zone (EDZ) in the slope. The damage reduces the acoustic wave velocity in the rock mass. Results of field tests measuring acoustic wave velocity at the Jinping I Hydropower Station are used here to study the EDZ in a tall rock slope. Two acoustic testing methods were adopted in the field tests: single-hole acoustic testing (SAT) and cross-hole acoustic testing (CAT). The acoustic wave velocity was lower in the EDZ, and the depth of the EDZ increased with decreasing slope elevation. Statistical analysis shows that the acoustic wave velocity obtained by the SAT method is larger than that obtained by the CAT method, and the relative difference between the SAT- and CAT-derived velocities is lower for a high quality rock mass than for a low quality rock mass. The integrity ratio and severity of damage can also be determined by acoustic wave velocity test results, revealing that the integrity ratio and elastic modulus of a rock mass are reduced in the EDZ.     

萃取分离—石墨炉原子吸收光谱法测定铅锌矿中的铟

样品经硝酸、氢氟酸分解除硅,加热硫酸冒烟除尽硝酸、氢氟酸,利用铟与氢溴酸能生成稳定的络合物并被乙酸丁酯萃取的性质,将铟与其它干扰离子分离并富集.使用MOLAARM6（Thermo Electron Corporation）石墨炉原子吸收分光光度计,以钒为机体改进剂,测定铅锌矿中的铟.方法检出限为LD=0.012ug/ml.实验结果令人满意.     

超声提取-固相萃取小柱净化-气相色谱法测定土壤中14种有机氯农药

对土壤中14种有机氯农药的超声提取技术和磺化、固相萃取小柱两种净化方法进行系统研究。结果表明,超声提取节省提取时间,提高分析效率;磺化法和固相萃取小柱法都有净化作用,但磺化法使样品中的艾氏剂、狄氏剂和异狄氏剂全部损失;固相萃取小柱净化当丙酮-正己烷淋洗液体积比为1∶9、淋洗液收集8 mL时回收率>90%,干扰最小。方法检出限为0.63~2.59μg/kg,精密度(RSD,n=7)为1.17%~14.66%,基体加标平均回收率为82.78%~106.94%。方法用于生态地球化学调查评价批量土壤样品的实际分析,检测结果满足评价工作需要。     

Comparison of linear and nonlinear shallow wave water equations applied to tsunami waves over the China Sea

This paper discusses the applications of linear and nonlinear shallow water wave equations in practical tsunami simulations. We verify which hydrodynamic theory would be most appropriate for different ocean depths. The linear and nonlinear shallow water wave equations in describing tsunami wave propagation are compared for the China Sea. There is a critical zone between 400 and 500 m depth for employing linear and nonlinear models. Furthermore, the bottom frictional term exerts a noticeable influence on the propagation of the nonlinear waves in shallow water. We also apply different models based on these characteristics for forecasting potential seismogenic tsunamis along the Chinese coast. Our results indicate that tsunami waves can be modeled with linear theory with enough accuracy in South China Sea, but the nonlinear terms should not be neglected in the eastern China Sea region.     

CMW工法在隧道基坑支护工程中的应用

在南京市城市快速内环北线二期隧道基坑支护工程的粉细砂复杂地层中首次成功应用了CMW工法,与钻孔灌注桩、钢板桩、地下连续墙、土钉墙和SMW工法等相比,具有污染小、造价低、速度快和施工质量好等优点。结合该工程实例,介绍了CMW工法施工的优点、工艺流程、设备选择、施工方法、安全管理要求和使用效果等。