Error analysis of rib curves based on measured data of airfoil-wainscot
The characteristics of accuracy control of large-scale airfoil-wainscot parts are analyzed. The accuracy of airfoil-wainscot is controlled by its rib curves, and the rib curves are straight lines whether after processing or before on the direction of face projection. The method of compensating the radius of measuring probe is presented also based on measuring data from 1D scanning probe. Aiming at the inspection requirement of the measured part and the characteristics of rib curves, the algorithms of curve matching and error analysis are proposed. The experimental results show that the proposed methods can meet the accuracy requirement of online inspection of airfoil-wainscot parts.
Surface reconstruction based on point cloud from laser scanning system
The characteristics of the point cloud obtained with laser scanning system are discussed in the paper, and a new algorithm of surface reconstruction based on point cloud is put forward. Based on the theory of B-spline curve and surface interpolation, the freeform curve and surface reconstruction method - we called the surface as loft surface - are introduced in detail. This method of surface reconstruction is adequately utilized the characteristics of the point cloud from laser scanning system. The experimental results testify that the method is effectual and feasible.
A traffic scheduling framework in broadband wireless access systems
In this paper, we present a traffic scheduling framework for allocating the upstream channel bandwidth in broadband wireless access systems, where both voice and data applications are supported. Our traffic scheduling framework is aimed at supporting diverse QoS requirements and obtaining high utilization of the upstream bandwidth. It prioritizes traffic streams according to different classes of service, and provides fair access of bandwidth to the users. The presented framework consists of three algorithms: a calibration algorithm for the jittered constant bit rate (CBR) traffic, a scheduling algorithm for the jittered CBR traffic, and a scheduling algorithm for the unspecified bit rate traffic. The proposed algorithms are feasible when either the asynchronous transfer mode or multi-protocol label switching protocol is deployed at the network edge. Simulation results are presented to demonstrate the effectiveness of our algorithms in achieving high bandwidth utilization and the good traffic performance in terms of both cell loss ratio and mean queuing delay.