scholarly journals An Integrated Investigation of Spatiotemporal Habitat Quality Dynamics and Driving Forces in the Upper Basin of Miyun Reservoir, North China

2018 ◽  
Vol 10 (12) ◽  
pp. 4625 ◽  
Author(s):  
Shengjun Yan ◽  
Xuan Wang ◽  
Yanpeng Cai ◽  
Chunhui Li ◽  
Rui Yan ◽  
...  

Understanding changes in habitat quality and the driving forces of these changes at landscape scales is a critical part of effective ecosystem management. The present study investigated spatiotemporal habitat quality dynamics and related driving forces from 2005 to 2015 in the upper basin of Miyun Reservoir in North China by constructing an effective framework integrated InVEST and binary logistic regression models. This framework expanded the driving force analysis into an assessment of changes in habitat quality and intuitively verified the effectiveness of relevant environmental policies. The proposed method of combining the equidistant random sampling method and the method of introducing spatial lag variables in logistic regression equation can effectively solve spatial autocorrelation with a large enough number of sampling points. Overall, habitat quality improved during the study period. Spatially, a concentrated loss of habitat occurred in the southeastern part of the basin between the reservoir and mountainous areas, while other areas gradually recovered. Driving force analysis showed that lower elevation mountain land, gentle slopes, locations near rural land or roads, larger areas of grain cultivation, and areas with little population change had a higher likelihood of having changed in habitat quality in the upper basin of Miyun Reservoir. These results suggested that the present policy of protecting the ecosystem had a positive effect on improving habitat quality. In the future, the human activity management related to habitat quality needs to be strengthened. The present study would provide a reference for land use policy formulation and biodiversity conservation.

Robotica ◽  
2011 ◽  
Vol 29 (6) ◽  
pp. 903-915 ◽  
Author(s):  
Zhu-Feng Shao ◽  
Xiaoqiang Tang ◽  
Xu Chen ◽  
Li-Ping Wang

SUMMARYThe Secondary Adjustable System (SAS) addressed here is a central component of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). It is a 6-degree-of-freedom rigid Stewart manipulator, in which one platform (the end-effector) should be controlled to track-desired trajectory when another platform (denoted as the base) is moving. Driving force analysis of the SAS is the basis for selecting rational servomotors and guaranteeing the dynamic performance, which will affect the terminal pose accuracy of the FAST. In order to determine the driving forces of the SAS, using the Newton–Euler method, the inverse dynamics of the Stewart manipulator is modeled by considering the motion of the base. Compared with the traditional dynamic models, the inverse dynamic model introduced here possesses an inherent wider application range. By adopting the kinematic and dynamic parameters of the FAST prototype, the driving force analysis of the SAS is carried out, and the driving force optimization strategies are proposed. Calculation and analysis presented in the paper reveal that there are three main factors affecting the driving forces of the SAS. In addition, the driving force analysis of this paper lays out guidelines for the design and control of the FAST prototype, as well as the structure and trajectory optimization.


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