两类多河道河流的形式模式及河道稳定性比较

在多河道河流中，网状河流作为有别于分汊河流和辫状河流的河型而提出已经引起人们的注意，但它与分汊河流的区别常常被忽略。为了阐明二者的根本差别，力求从多河道形成模式上对二者进行比较研究。通过对长江下游分汊河流及荆江风状河流特定河段形成历史及方式的探索，提出河道内的江心洲化模式和河漫滩上的河道化模式分别是分汊河流和网状河流形成的基本途径。由此而决定了网状河道具有分汊河流更高的稳定性。     

Flood hazard in Hunan province of China: an economic loss analysis

Natural and man-made disasters have been increasing and affecting millions of people throughout the world. Floods are the most common natural disasters affecting more people across the globe than all other natural or technological disasters and also are the most costly in terms of human hardship and economic loss. In order to explore the total economic loss, components of economic loss, and factors influencing economic loss during flooding, a retrospective study was carried out in year 2000 in areas that suffered floods in 1998 in Hunan province, China. A total of 10,722 families were investigated using a multistage sampling method. We found that the total economic loss to the 10,722 families investigated was US$ 8.925 million; translating into an average economic loss of US$ 832.45 per family and US$ 216.75 per person. Economic loss related to property loss, income loss, and increased medical cost accounted for 57.38%, 40.00%, and 2.62% of the total economic loss, respectively. Economic loss was significantly related to a family’s pre-flood income; duration of the flood; severity of flood; and type of flood. River floods yielded the highest economic loss and drainage problem floods yielded the lowest loss. We recommended that flood-related preventive measures should focus on the prevention of river floods and shortening the duration of floods with the view of significantly minimizing economic losses associated with floods.     

A comparative approach to modelling multiple urban land use changes using tree-based methods and cellular automata: the case of Greater Tokyo Area

Urban multiple land use change (LUC) modelling enables the realistic simulation of LUC processes in complex urban systems; however, such modelling suffers from technical challenges posed by complicated transition rules and high spatial heterogeneity when predicting the LUC of a highly developed area. Tree-based methods are powerful tools for addressing this task, but their predictive capabilities need further examination. This study integrates tree-based methods and cellular automata to simulate multiple LUC processes in the Greater Tokyo Area. We examine the predictive capability of 4 tree-based models – bagged trees, random forests, extremely randomised trees (ERT) and bagged gradient boosting decision trees (bagged GBDT) – on transition probability prediction for 18 land use transitions derived from 8 land use types. We compare the predictive power of a tree-based model with multi-layer perceptron (MLP) and among themselves. The results show that tree-based models generally perform better than MLP, and ERT significantly outperforms the three other tree-based models. The outstanding predictive performance of ERT demonstrates the advantages of introducing bagging ensemble and a high degree of randomisation into transition probability modelling. In addition, through variable importance evaluation, we found the strongest explanatory powers of neighbourhood characteristics for all land use transitions; however, the size of the impacts depends on the neighbourhood land use type and the neighbourhood size. Furthermore, socio-economic and policy factors play important roles in transitions ending with high-rise buildings and transitions related to industrial areas.     

Knowledge-guided consistent correlation analysis of multimode landslide monitoring data

A novel method called knowledge-guided spatio-temporal consistent correlation analysis (KSTCCA) was developed to discover reliable deformation features induced by multiple factors based on multimode landslide monitoring data. Compared to conventional approaches, KSTCCA integrates both temporal and spatial correlation analysis to improve the consistency of deformation patterns and capture the spatio-temporal heterogeneities in multimode monitoring data. KSTCCA considers both the landslide deformation mechanisms and the relationships between different influential factors as knowledge. Moreover, the method extracts the morphological structures of monitoring curves based on a seven-point approach and identifies knowledge rules using the k-means clustering method. Under the guidance of prior knowledge, a spatial correlation analysis is conducted based on support vector regression, and a temporal correlation analysis of the time lag is carried out based on the morphological structure features. Finally, three kinds of typical monitoring data, including deformation, rainfall, and reservoir water level data collected in the Baishuihe landslide area, China, are used for experimental analysis to verify the validity of the proposed method.     

An analysis on location factors affecting the spatial distribution of Shanghai land values

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城市测量控制网的设计

本文以优化设计的实施性为目的,采用模拟法进行二类及三类城控网的设计。二类设计在算法上采用矩阵反演公式来提高计算速度及保证结果的优良性;三类设计（加测元素最佳位置的确定）使用敏感测度,并顾及周围边长精度的改变状况,构成多目标函数的最优数学模型,最后对大型网进行了详细的分析和说明。     

Rock-mass characterization using intrinsic and scattering attenuation estimates at frequencies from 400 to 1600 Hz

Intrinsic and scatteringS-wave quality factors (Q ) were estimated using the Multiple Lapse Time Window Analysis (MLTWA) for microseismic events (M<–1) with source-sensor distances of 45 to 120 m, associated with an excavation at 630 m depth in Strathcona Mine, Sudbury, Canada. Additional information on the rock mass was provided by underground structural mapping data. IntrinsicQ values, at 800 Hz, were on the order of 140, similar to quality factor values obtained in previous studies using Spectral Decay and Coda-Q methods (120 to 170). The scattering quality factor at this frequency was about 520. An observed frequency dependence of the scattering attenuation suggested that a decrease in the density of scatterers, with scale lengths on the order of 2 m, exists at the site. Characteristic fracture scale lengths were considered to range from 4 to 6 m as identified in the mapping data. These observations were supported by the increase in scattering found for seismic waves with frequencies less than 1000 Hz. By assuming that the identified scatters are characteristic faults, these scatterers can then be considered to increase nonsimilar behavior in source scaling. Overall, our results suggest that MLTWA provides a practical method for remotely characterizing the quality of a rock mass when visual observations are not attainable.     

重力式海洋平台的运动响应

本文在分析重力式海洋平台的力学模型基础上，建立了平台运动的拉格朗日方程，并用多尺度法求解平台的运动响应。     

Estimating Daily Egg Production of European Anchovy in the Adriatic Sea: A Critical Appraisal

Abstract. We discuss the critical problem of estimating daily egg production in the Daily Egg Production Method (DEPM), a widely used technique for the stock assessment of multiple spawning pelagic fishes. Data collected in 1999 for the stock of European anchovy ( Engraulis encrasicolus ) in the Southern Adriatic Sea are used to study the effects of different calibration techniques. We analyze the performances of the mortality model from which daily egg production is estimated. All these calibrations are based on the Bootstrap method. Nonlinear fitting (vs. linear regression on log-transformed data) is shown to guarantee more reliable parameter estimation. We show that specifying the function assigning age to staged eggs is crucial.