Comparison of two approaches for detecting the depth of edge influence on vegetation diversity in the arid valley of southwestern China

Three types of landscape boundary (forest/pepper field, forest/cabbage field,and forest/grassland) were selected in the arid valley of upper reaches of Minjiang River,southwestern China. On the basis of vegetation diversity, the depth of edge influence (DEI) ondifferent types of landscape boundaries was estimated using principal components analysis (PCA)method and moving split-window techniques (MSWT). The results showed that in the 5 transects, PCAmethod was able to detect the edge influence depth with 3 transects, while MSWT could explain 4transects. It is concluded that PCA and MSWT both can be used to detect the depth of edge influencewithin 50 m from the edge to the interior. Similar conclusions were drawn in the forest of eachtransect with the two methods, but no similar conclusions were drawn in the pepper field of eachtransect. Although the two methods have advantages and disadvantages respectively, they are usefultools for characterizing edge dynamics. Comparing the two methods, MSWT is more successful.

Innovation Analysis Approach to Design Parameters of High Speed Train Carriage and Their Intrinsic Complexity Relationships

In view of the problem that it＇s difficult to accurately grasp the influence range and transmission path of the vehicle top design requirements on the underlying design parameters. Applying directed-weighted complex network to product parameter model is an important method that can clarify the relationships between product parameters and establish the top-down design of a product. The relationships of the product parameters of each node are calculated via a simple path searching algorithm, and the main design parameters are extracted by analysis and comparison. A uniform definition of the index formula for out-in degree can be provided based on the analysis of out- in-degree width and depth and control strength of train carriage body parameters. Vehicle gauge, axle load, crosswind and other parameters with higher values of the out-degree index are the most important boundary condi- tions; the most considerable performance indices are the parameters that have higher values of the out-in-degree index including torsional stiffness, maximum testing speed, service life of the vehicle, and so on; the main design parameters contain train carriage body weight, train weight per extended metre, train height and other parameters with higher values of the in-degree index. The network not only provides theoretical guidance for exploring the relationship of design parameters, but also further enriches the appli- cation of forward design method to high-speed trains.