Internet环境下用Java/JDBC实现地理信息的互操作与分布式管理及处理

Ｉｎｔｅｒｎｅｔ／Ｉｎｔｒａｎｅｔ的蓬勃发展,使得网络地理信息系统下地理信息的互操作成为可能。本文探讨了在分布式环境中如何利用Ｊａｖａ／ＪＤＢＣ实现ＧＩＳ多数据源的互操作与分布式处理。     

NUMERICAL SIMULATION OF SEDIMENT TRANSPORT IN DYNAMIC FLOW CONDITIONS

1 INTRODUCTION Rivers as a source of life can at the same time impose devastating conditions on the environment. It is , therefore, imperative to analyse and predict river behaviour for different given conditions and engineering activities. Therefore, the use of simulation tools in this field has become a necessity. Many computational tools for simulation of sediment transport in rivers are now available that can be used for prediction and design under different flow conditions. However, …     

Environmental impact assessment of open pit mining in Iran

Mining is widely regarded as having adverse effects on environment of both magnitude and diversity. Some of these effects include erosion, formation of sinkhole, biodiversity loss and contamination of groundwater by chemical from the mining process in general and open-pit mining in particular. As such, a repeatable process to evaluate these effects primarily aims to diminish them. This paper applies Folchi method to evaluate the impact of open-pit mining in four Iranian mines that lacked previous geo-environmental assessment. Having key geologic resources, these mines are: Mouteh gold mine, Gol-e-Gohar and Chogart iron mines, and Sarcheshmeh copper mine. The environmental components can be defined as public health and safety, social relationships, air and water quality, flora and fauna hence, various impacting factors from the mining activities were estimated for each environmental component. For this purpose, each impacting factor was first given a magnitude, based solely on the range of possible scenarios. Thereafter, a matrix of weighted factors was derived to systematically quantify and normalize the effects of each impacting factor. The overall impact upon each individual environmental component was then calculated by summing the weighted rates. Here, Folchi method was applied to evaluate those environmental conditions. Based on the acquired results, the present paper finally concludes that amongst four case histories in Iran, Sarcheshmeh copper mine significantly affects the environment, with critical level of air pollution there.     

微热弯成形的微位移计算机视觉测量方法

为实现微热弯成形系统中微位移的高精度测量,构建了微位移计算机视觉测量系统.应用Matlab编写摄像机标定程序并计算摄像机的内外参数,利用OpenCV对被测对象的图像进行灰度化、二值化和Canny边缘提取,采用序贯相似性检测算法(SSDA)进行模板匹配,实现了热弯曲成形过程中模具与工件位置微位移的实时在线检测.实验结果表明,该系统对微位移的测量具有操作简单、高效的特点.     

On the study of control effectiveness and computational efficiency of reduced Saint-Venant model in model predictive control of open channel flow

Model predictive control (MPC) of open channel flow is becoming an important tool in water management. The complexity of the prediction model has a large influence on the MPC application in terms of control effectiveness and computational efficiency. The Saint-Venant equations, called SV model in this paper, and the Integrator Delay (ID) model are either accurate but computationally costly, or simple but restricted to allowed flow changes. In this paper, a reduced Saint-Venant (RSV) model is developed through a model reduction technique, Proper Orthogonal Decomposition (POD), on the SV equations. The RSV model keeps the main flow dynamics and functions over a large flow range but is easier to implement in MPC. In the test case of a modeled canal reach, the number of states and disturbances in the RSV model is about 45 and 16 times less than the SV model, respectively. The computational time of MPC with the RSV model is significantly reduced, while the controller remains effective. Thus, the RSV model is a promising means to balance the control effectiveness and computational efficiency.     

基于多目标决策的露采矿山空间整合研究——以江苏省徐州市为例

空间整合是优化露采矿山布局的重要手段,科学制定空间整合方案至关重要。以徐州为例,在分析了影响露采矿山空间整合主要因素的基础上,拟定了空间整合的若干备选方案;以多目标决策理论为支撑,运用专家咨询法、层次分析法、灰色关联度分析等方法,定性结合定量对各备选方案进行综合评价,筛选出最优方案。研究对徐州市矿产资源开发整合具有指导作用,在矿业布局优化研究方面也存在较大理论价值和借鉴意义。     

Transparent boundary condition for simulating nonlinear water waves by a particle method

Open boundaries are important when simulating water waves. In this study, a transparent boundary condition at an open boundary was developed for simulating nonlinear water waves propagating to a distant area using the Moving Particle Semi-implicit method. The novelty of this study is that the technique of wave analysis used in the experiment was introduced into the particle simulation to absorb incident waves; the simulation cost was reduced by employing inflow and outflow regions instead of a long dissipation region. Incident waves in front of the boundary were evaluated using Fourier analysis, and the particles on the transparent boundary were forced to move at the velocity of the analytical solution for Stokes waves in order to absorb the incident waves. The analysis was restricted to periodic waves. Wave propagation was simulated for two wave periods using the developed transparent boundary condition. The results showed that this transparent boundary transmitted the incident waves with small reflection and the simulation cost was lower than that for wave damping by a conventional highly viscous region.     

Invasion genetics of Pacific oyster Crassostrea gigas shaped by aquaculture stocking practices

As a result of aquaculture activities Pacific oysters Crassostrea gigas (Thunberg, 1793) have invaded the European Wadden Sea. Using a variable noncoding mitochondrial marker, we show that the invaded range is the result of two independent invasions. Haplotype frequencies point towards two separate groups, one in the southern and the other in the northern Wadden Sea. We found virtually no genetic differentiation throughout the southern range and the putative source from British Columbia, Canada, suggesting that the Southern region can be considered as a closed population. In the North, mismatch distributions, haplotype ordination and isolation-by-distance analysis suggest a stronger, persistent impact of aquaculture on invasive populations. Due to the ongoing supply of new genetic material from hatchery production the northern invasive populations can therefore be considered as an open population highlighting the importance of aquaculture practice on the genetics of this keystone invader in the Wadden Sea.     

Impacts of CO2 Enrichment on Water Use Efficiency in Terrestrial Ecosystems: A Meta-analysis of Experimental Manipulations

Elevated CO₂ (eCO₂) has important impacts on plants, especially on water use efficiency (WUE). A meta-analysis was performed to determine the responses of WUE to enriched CO₂. We summarized 242 studies on WUE research under ambient and enriched CO₂ conditions that were published between 1989 and 2019. Our results showed that WUE had positive responses to elevated CO₂ with an increase of about 46% and high heterogeneity. Elevated CO₂ increased leaf, grain, biomass and whole plant WUE by 76%, 9%, 30% and 37%, respectively. The effect size on leaf WUE was higher than the other three WUE types, and the effect size on whole plant WUE was higher than grain WUE (P<0.05). In another respect, the response of WUE in forests was higher than in cropland (P<0.05). Regarding different experimental methods, WUE had a stronger response to elevated CO₂ by the method of climate-controlled chamber than by the methods of OTC (Open Top Chamber) or greenhouses (P<0.05). However, the effect size obtained by the method of greenhouse was higher than that obtained by the methods of either OTC or climate chamber for whole plant WUE (P<0.05). Furthermore, our results found WUE had a positive linear relationship with the magnitude of CO₂ enrichment (P<0.05). Meanwhile, the effect size of elevated CO₂ on grain WUE had a positive linear relationship with the duration of CO₂ enrichment. This study found that the impacts of CO₂ enrichment on WUE are unique and specific for different WUE types and the various experimental conditions.