Fingerprint matching is a key issue in research of an automatic fingerprint identification system. On the basis of triangulation in computational geometry, we develop a kind of method for fingerprint matching based on Delaunay Triangulation net in this paper. Through carrying on Delaunay Triangulation to the topological structure of fingerprint minutiae, minutiae with closer distance link to each other on the space according to the Delaunay criterion and form the Delaunay Triangulation net. Then look for some reference minutiae pairs correctly from the net. According to the reference minutiae pairs, match fingerprint on point pattern. The experimental results on FVC2000 indicate the validity of algorithm.
The supervisory control and data acquisition (SCADA) technology has been used in water distribution systems in recently years, in which, waterhead at some nodes and/or flowrate in some links in the water distribution systems are monitored by radio or internet, and the waterhead and flowrate monitoring stations are usually determined by experience or simply evenly distributed. For the purpose of more efficient monitoring, optimal monitoring of waterhead in a water distribution system was developed by the authors, and as the second part of the study, this paper has proposed a method for optimal monitoring of flowrate in a water distribution system. A perturbation analysis is conducted to determine the sensitivity matrix, and the sensitivity equation is solved by a least square method, and the optimal monitoring of flowrate is then decided. The optimal monitoring solution is compared with the evenly distributed case, and it is found the optimal monitoring provides a more efficient and practical scheme if the number of monitoring stations is specified.
It is shown that water distribution systems can be damaged by earthquakes, and the seismic damages cannot easily be located, especially immediately after the events. Earthquake experiences show that accurate and quick location of seismic damage is critical to emergency response of water distribution systems. This paper develops a methodology to locate seismic damage -- multiple breaks in a water distribution system by monitoring water pressure online at limited positions in the water distribution system. For the purpose of online monitoring, supervisory control and data acquisition (SCADA) technology can well be used. A neural network-based inverse analysis method is constructed for locating the seismic damage based on the variation of water pressure. The neural network is trained by using analytically simulated data from the water distribution system, and validated by using a set of data that have never been used in the training. It is found that the methodology provides an effective and practical way in which seismic damage in a water distribution system can be accurately and quickly located.
The supervisory control and data acquisition (SCADA) technology is commonly used in water distribution systems in recently years. Monitoring is one of the most important steps in SCADA's implementation, and in reality monitoring stations used for water pressure are usually decided by experience or simply evenly distributed. For the purpose of more efficient monitoring, a method for optimal monitoring of water pressure in a water distribution system is proposed in this paper, in which, a sensitivity analysis is conducted for determining the sensitivity equation, and the sensitivity equation is then solved by a least-square method. It is found from examples that the method provides an efficient and practical way in which optimal monitoring scheme of water distribution system may be decided.
Breaks often occur to urban water distribution systems under severely cold weather, or due to corrosion of pipes, deformation of ground, etc., and the breaks cannot easily be located, especially immediately after the events. This paper develops a methodology to locate a break in a water distribution system by monitoring water pressure online at some nodes in the water distribution system. For the purpose of online monitoring, supervisory control and data acquisition (SCADA) technology can well be used. A neural network-based inverse analysis method is constructed for locating the break based on the variation of water pressure. The neural network is trained by using analytically simulated data from the water distribution system, and validated by using a set of data that have never been used in the training. It is found that the methodology provides a quick, effective, and practical way in which a break in a water distribution system can be located.
Based on vision inspection technique, the measurement system for measuring complexity free form surface is developed. For getting the high-accuracy object surface, subpixel subdivision technology is studied. For the sake of the data got from the measurement are scatted measuring points, modeling technique for triangular meshes should be used. The basic idea of the approach based on Bezier interpolation can be expressed. A practical algorithm for free form surface reconstruction combining Bezier triangulation modeling and NURBS rectangular modeling is proposed. In 3-D digital image modeling the merging of depth images is one of the key techniques, which directly affects the quality of depth image merging. The multi-view image data processing is introduced. Serve the turbine blade as the object, with coordinate measuring machine, the demonstrations of the designed measuring system and the image processing method are proved. The results indicate that the studied method of the paper is high accuracy, speediness practicality characteristics for measuring the complexity free form surface.
Turbine blade is high-reflective metal surface, which has much difficulty in measurement. Based on vision measurement technique and the metal superficial polarization characteristic, the probe system with three cameras is developed. On the basis of geometry model, the impacts of structure parameters on vertical resolution ratio of the system are analyzed and the parameters are designed, which offer the theoretical foundation of sculptured high accuracy surface measurement online. In measurement, the CCD calibration is very important. Combining with Tsai algorithm, the camera model is built, the uncertainty image scale factor sx scan be got, and the other parameters can be received easily. With the method of the paper, the experiment of high-reflective surface measurement of gauge block is carried on. The results indicate that the measuring device has high measurement accuracy, which can be widely used in practice.