AN IMPROVED LEVEL-SET RE-INITIALIZATION SOLVER

Re-initialization procedure in level-set interface capturing method were investigated. The algorithm accomplishes the re-initialization step through locking the interface positions. Better accuracy was obtained both on the interface positions and the total fluid volume keeping. Though one more step of the interpolations is added in the procedure, there is no significant increase in total machine time spent.

Assessment of Dynamic Downscaling of the Extreme Rainfall over East Asia Using a Regional Climate Model

This study investigates the capability of the dynamic downscaling method （DDM） in an East Asian climate study for June 1998 using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research non-hydrostatic Mesoscale Model （MM5）.Sensitivity experiments show that MM5 results at upper atmospheric levels cannot match reanalyses data,but the results show consistent improvement in simulating moisture transport at low levels.The downscaling ability for precipitation is regionally dependent.During the monsoon season over the Yangtze River basin and the pre-monsoon season over North China,the DDM cannot match observed precipitation.Over Northwest China and the Tibetan Plateau （TP）,where there is high topography,the DDM shows better performance than reanalyses.Simulated monsoon evolution processes over East Asia,however,are much closer to observational data than reanalyses.The convection scheme has a substantial impact on extreme rainfall over the Yangtze River basin and the pre-monsoon over North China,but only a marginal contribution for Northwest China and the TP.Land surface parameterizations affect the locations and pattern of rainfall bands.The 10-day re-initialization in this study shows some improvement in simulated precipitation over some sub-regions but with no obvious improvement in circulation.The setting of the location of lateral boundaries （LLB） westward improves performance of the DDM.Including the entire TP in the western model domain improves the DDM performance in simulating precipitation in most sub-regions.In addition,a seasonal simulation demonstrates that the DDM can also obtain consistent results,as in the June case,even when another two months consist of no strong climate/weather events.

Application of radial basis functions to evolution equations arising in image segmentation

In this paper, radial basis functions are used to obtain the solution of evolution equations which appear in variational level set method based image segmentation. In this method, radial basis functions are used to interpolate the implicit level set function of the evolution equation with a high level of accuracy and smoothness. Then, the original initial value problem is discretized into an interpolation problem. Accordingly, the evolution equation is converted into a set of coupled ordinary differential equations, and a smooth evolution can be retained. Compared with finite difference scheme based level set approaches, the complex and costly re-initialization procedure is unnecessary. Numerical examples are also given to show the efficiency of the method.

REGION-BASED ACTIVE CONTOUR DRIVEN BY GLOBAL INTENSITY FITTING ENERGY

In this paper, we present a novel region-based active contour model based on global in-tensity fitting energy in a variational level set framework. Meanwhile, an internal energy term is in-troduced, and it forces the level set function to be close to a signed distance function. Image global information utilized efficiently makes the proposed model insensitive to noise, and the introduced penalty term can avoid the costly re-initialization for the evolving level set function, which not only speeds up the contour evolvement, but also improves accuracy of the final contour. Comparisons with other classical region-based models, such as Chan-Vese model and Region-Scalable Fitting (RSF) model, show the advantages of our model in terms of efficiency and accuracy. Moreover, the model is robust to noise.

Research of Rural Power Network Reactive Power Optimization Based on Improved ACOA

In view of the serious reactive power loss in the rural network, improved ant colony optimization algorithm （ACOA） was used to optimize the reactive power compensation for the rural distribution system. In this study, the traditional ACOA was improved in two aspects： one was the local search strategy, and the other was pheromone mutation and re-initialization strategies. The reactive power optimization for a county＇s distribution network showed that the improved ACOA was practicable.

An origin of ultraslow spreading ridges for the Yarlung-Tsangpo ophiolites

As relics of ancient ocean lithosphere,ophiolites are the most important petrological evidence for marking the sutures and also play a key role in reconstructing plate configuration.They also provide valuable windows for studying crustal accretion and mantle processes occurring at modem ocean ridges.Abundant ophiolites are distributed along the Yarlung-Tsangpo suture and represent the relics of ocean lithosphere of the Neo-Tethys.They are characterized by an incomplete litho-stratigraphy,of which the mantle section is much thicker than the crustal section.Ocean crustal rocks outcropped in the Yarlung-Tsangpo ophiolites are much thinner than normal ocean crusts(~7 km)or even absent.Tectonic settings from which the Yarlung-Tsangpo ophiolites originated remain highly controversial,although an origin of the supra-subduction zone is prevailing.Moreover,their incomplete litho-stratigraphy has been commonly attributed to tectonic dismemberment during the late-stage emplacement after their formation.Nevertheless,such an incompleteness resembles the ocean lithosphere generated at modem ultraslow spreading ridges,such as the Southwest Indian Ridge(SWIR).In this paper,we present several lines of evidence that support the formation of the Yarlung-Tsangpo ophiolites at ultraslow spreading ridges,during which detachment faults were developed.This suggests that the Yarlung-Tsangpo ophiolites might represent the ocean core complexes(OCC)in the Neo-Tethys Ocean.The OCC with high topography in the seafloor were clogged in the trench and preserved as ophiolites through Indo-Eurasia collision.The clogging resulted in the demise of an old subduction and a new subduction was re-initiated beneath the clogged OCC.

A New Variational Model with Dual Level Set Functions for Selective Segmentation

In this paper we present a selective segmentation model using a dual level set variational formulation.Our variational model aims to segment all objects with one level set function(global)and the selected object,which is the closest to the geometric constraints(markers),with another level set(local).It is a combination of edge detection,markers distance function and active contour without edges.Experimental results show that our model is more robust than previous work.