基于Paxos的强一致性复制在天文数据存储中的应用研究

随着新一代天文观测技术的快速发展,观测设备所获得的科学数据迅猛增长,传统的外挂式存储设备已经难以满足海量观测数据的近实时存储和同步数据处理的需求。基于廉价硬件的分布式存储系统是解决当前天文观测数据存储的有效手段。由于廉价硬件节点发生故障的概率相对较高,为了确保科学观测和数据的可靠存储,提出了一种基于Paxos的改进的分布式软件多副本复制算法。实验表明,在针对大于1 MB的天文FITS图像文件存储过程中,算法虽然增加少量的存储延迟,但能够容忍多种软硬件异常下多个副本的强一致性,较好地解决当前海量天文数据存储中的多副本数据存储的一致性问题。     

Increased soil organic carbon storage in Chinese terrestrial ecosystems from the 1980s to the 2010s

Journal of Geographical Sciences - Soil stores a large amount of the terrestrial ecosystem carbon (C) and plays an important role in maintaining global C balance. However, very few studies have...     

Phosphorus storage,transport and export dynamics in the Foron River watershed

Phosphorus (P) export from the Foron River watershed was intensively monitored. Water was analysed for total P, soluble total P, soluble orthophosphate and suspended solids. Watershed soils and river sediments were sampled and the size fraction <0·2 mm analysed for total P, water extractable P, bioavailable P, 1 minute exchangeable P and P fixation capacity. Interstitial waters were analysed for soluble total P. Four hydrological conditions recurred, two during low river flows and two during increased flow. The first occurs in dry weather with a constant or decreasing flow over at least seven days and when there is no surface runoff. Exported phosphorus, predominately soluble and bioavailable, is from point sources. Phosphorus inputs exceed P export so P accumulates in the river. The second condition occurs when a small storm flow increases the average seven-day flow to exceed the preceding weekly average. Phosphorus export exceeds P inputs and originates from urban runoff, point sources and release of P stored in the river. Exported P is largely particulate but highly bioavailable. The third condition is when substantial runoff follows at least a seven-day period of constant or decreasing flow. Phosphorus export is from diffuse urban runoff. All the P stored is exported. Exported P is highly bioavailable. High concentrations and fluxes of P export are often seen. The fourth condition happens when the soils are wet and increased flow is from both urban and agricultural runoff. Phosphorus export from diffuse agricultural runoff predominates and is largely not bioavailable. Phosphorus concentrations are low but export fluxes are high when flows are high. These hydrological conditions, when integrated with concepts of mass balance define a phosphorus export typology comprising four regimes. These regimes explain total phosphorus (TP) storage, transport and export patterns, changes in P speciation and allow identification of probable sources of TP in the Foron river watershed. © 1998 John Wiley & Sons, Ltd.     

基于防洪库容总量控制的雅砻江下游梯级水库蓄水策略研究

根据长江防御洪水方案对雅砻江梯级水库的防洪库容预留要求,分析了预留防洪库容对梯级电站蓄水发电的影响。结合雅砻江水电开发的特点,提出了梯级水库防洪库容总量控制的解决思路,建立了基于防洪库容总量控制的蓄水期发电量最大模型,计算分析了9种不同来水情景的梯级水库优化蓄水方案,并给出了梯级水库总体优化蓄水策略。对该类问题研究具有一定借鉴意义。     

Petrology,geochronology,and geophysical characterization of Mesoproterozoic rocks in central Illinois,USA

The Precambrian basement rocks of the Eastern Granite-Rhyolite Province(EGRP)in central Illinois(midcontinent region of North America)exhibit a complex history of early volcanism,granite emplacement,and intrusion of mafic rocks.A comprehensive suite of dedicated petrographic analyses,geophysical logs,and drill core from four basement-penetrating wells,two-dimensional and three-dimensional seismic reflection data,and U-Pb age data from the Illinois Basin–Decatur Project(IBDP)and Illinois Carbon Capture Storage(ICCS)Project site provide new constraints for interpreting the Precambrian basement of the Illinois Basin.These new data reveal the basement to be compositionally and structurally complex,having typical EGRP felsic volcanic rocks intruded by the first reported gabbro in the Precambrian basement in Illinois.Zircons(n?29)from rhyolite give a U-Pb weighted mean average age of 14679 Ma.Zircons(n?3)from a gabbro dike that intrudes the rhyolite yield a concordia age of 107312 Ma,which corresponds to Grenville-age extension and represents the first Grenville-age rock in Illinois and in the EGRP.A high-resolution three-dimensional seismic reflection volume,coincident with the four wells,provides a context for interpreting the petrological data and implies a high degree of heterogeneity for basement rocks at the IBDP–ICCS site,as also shown by the drill cores.The occurrence of Grenville-age gabbro is related to a prominent bowl-like structure observed on local two-dimensional seismic reflection profiles and the three-dimensional volume that is interpreted as a deep-seated mafic sill complex.Furthermore,heterogeneities such as the brecciated EGRP rhyolite and later gabbro intrusion observed in the basement lithology at the IBDP–ICCS may reflect previously unknown distal elements of the 1.1 Ga Midcontinent Rift in the EGRP and more likely Grenville-age extension.     

Multi-scale solution for building extraction from LiDAR and image data

This paper presents a multi-scale solution based on mathematical morphology for extracting the building features from remotely sensed elevation and spectral data. Elevation data are used as the primary data to delineate the structural information and are firstly represented on a morphological scale-space. The behaviors of elevation clusters across the scale-space are the cues for feature extraction. As a result, a complex structure can be extracted as a multi-part object in which each part is represented on a scale depending on its size. The building footprint is represented by the boundary of the largest part. Other object attributes include the area, height or number of stories. The spectral data is used as an additional source to remove vegetation and possibly classify the building roof material. Finally, the results can be stored in a multi-scale database introduced in this paper. The proposed solution is demonstrated using the data derived from a Light Detection And Ranging (LiDAR) surveying flight over Tokyo, Japan. The results show a reasonable match with reference data and prove the capability of the proposed approach in accommodation of diverse building shapes. Higher density LiDAR is expected to produce better accuracy in extraction, and more spectral sources are necessary for further classification of building roof material. It is also recommended that parallel processing should be implemented to reduce the computation time.     

全数字摄影测量系统在抽水蓄能电站中的应用

结合文登抽水蓄能电站阐述了全数字摄影测量系统在抽水蓄能电站中的应用。     

Public acceptance of the oceanic carbon sequestration

CO₂ ocean sequestration may be an effective option for mitigating global warming. There are risks associated with this process, particularly the local impact on deep-sea environments. Public acceptance is required for the implementation of this technology, even though the impacts have been proven to be trivial. In this study, a questionnaire survey was conducted to find the correlation between public acceptance of CO₂ sequestration and influential factors by covariance structure analysis. In addition, risk communication via the Internet was carried out. These analyses revealed that careful investigation of the target oceanic site and field experiments are important in gaining public acceptance of CO₂ sequestration.     

水下储油保温监控系统研究

为了实现水下高效安全储油,对油水置换式水下储油及其监控技术进行了深入地研究,提出了油水隔离柔性储油方法.运用现场总线技术研制了水下储油保温监控系统.该系统采用基于神经网络的软测量方法实现隔离保温腔内高凝原油温度监测;运用热线测试技术实现保温性能在线监测;基于泛布尔代数的模糊逻辑控制方法进行原油保温加热控制.     

中国森林生态系统植被碳储量时空动态变化研究

森林是陆地生态系统的主体, 在全球碳循环中起着十分重要的作用。本文利用20 世纪70 年代以来的六次森林清查资料, 结合森林生物量实测数据, 采用分树种、分龄组的生物量—蓄积 拟合关系, 估算了中国20 世纪70 年代以来森林植被碳储量的动态变化。结果表明: 我国六次森 林资源清查中森林的植被总碳储量分别为3.8488PgC、3.6960PgC、3.759PgC、4.1138PgC、 4.6563PgC 和5.5064PgC, 虽然存在一定的波动现象, 但总体增长趋势明显, 尤其是80 年代以来, 植被碳储量净增加1.8104PgC, 平均每年以0.0823PgC 的速率增加, 这表明80 年代以来我国森林 植被一直起着明显的CO₂ 汇的作用。从碳密度的变化看, 70 年代以来我国森林植被平均碳密度 增长了3.001Mgha ^-1, 其中幼龄林与中龄林碳密度分别增长5.2871Mgha ^-1 和0.6022 Mgha ^{-1<,sup>, 而成 熟林碳密度却降低了0.7581Mgha -1, 可见中国森林植被的碳汇功能主要来自于人工林的贡献, 而 且随着幼龄林、中龄林碳储量和碳密度的增长, 中国森林植被的碳汇功能将进一步增强。我国森 林植被碳储量和碳密度空间差异显著, 森林植被碳库主要集中于东北和西南地区, 平均碳密度以 西南、东北以及西北地区为大, 中国森林植被碳储量和碳密度的这种空间分布规律与人类活动对 森林的干扰强度密切相关。}