Applied Mechanics and Materials Vols. 170-173

Abstract: We study the optimization of surveying engineering for sustainable development based on the parameterized distribution formulation and try to find out the way to realize the optimum surveying engineering for sustainable development. We used the parameterized distribution formulation for reference to establish the model system and we treated the compensation as the influential factor in this model system. Conclusion could be drawn that the optimization of surveying engineering could be realized for sustainable development by choosing the right influential factor.

Abstract: The Vivaldi antennas are widely used in many wide band electronic systems for its good performances. This paper designed and simulated two kinds of Vivaldi antennas for wide band passive radar applications, which are the antipodal Vivaldi antenna fed by strip line and antipodal Vivaldi antenna fed by microstrip line. The specific design parameters and the radiation performances of each kind of vivaldi antenna are provided over the operating frequency range of 3GHz to 11GHz. Furthermore a circular antenna array with six Vivaldi antenna elements fed by microstrip lines was also simulated to obtain its radiation performances over the operating frequency range of 3GHz to 8GHz. The simulation results demonstrate the designed Vivaldi antennas have acceptable performances of voltage standing wave ratio (VSWR), patterns and gains, so they can be used in practical wide band radars.

Abstract: The Earth gravitational field model EGM2008 with the high resolution has been applied in data processing and analysis in practical geodetic and geophysical study. We calculate the deflection of the vertical on testing areas in China from EGM2008 with the different grids based on the geopotential theory. What’s more, the precisions of the deflection of the vertical determined with EGM2008 up to different degrees and orders are compared and analyzed by calculating the actual astro-geodetic data and modelled data to evaluate the regional quality of EGM2008 with in situ data. Precisions of meridian and prime vertical components of vertical deflections estimated with EGM2008 up to 2190 degrees are 1.59″ and 1.74″, respectively.

Abstract: For unit weight mean square error of no-equal precision independent surveying values,this paper summed up several old estifying methods, pointed out their scarcities or mistakes, and advanced a sort of new method- maximum likelihood estimation method which is simple and strict.This is useful for theory of unit weight mean square error of no-equal precision independent surveying values to be perfect and for college surveying textbook to be improved and unified.

Abstract: When measuring the coaxiality of a cylinder, we often get the poor reproducibility of measurement results. This phenomenon is related not only to its measuring machine condition, but also to the measuring method. The main factors that cause measurement errors are analyzed in this paper, and some solutions to improve the measurement results are provided.

Abstract: It is the scientific basis of instructing the project to produce and operate that the deformation is monitored, and the analysis and prediction in constructing and operating of project is one of the important jobs. In order to analyze and predict the deformation of the project more timely and accurately, the paper analyzed and established the feasibility of wavelet-grey predicting model on the basis of the grey system theory in modeling limitations and the characteristics of wavelet transformation. With the comparison of predictive datas in two kinds of models, the results show, the predictive datas of the wavelet-grey model are more accurately than grey model’s, and has achieved good results in prediction of the engineering, is a feasible method.

Abstract: For solving the technical problem of accuracy control during manufacturing and vertically matching the curved steel tower of the bridge, this paper studies the accuracy control technique about it, as project example with the world’s first curved steel tower of No.3 Nanjing Yangtze River Bridge in China. Emphatically research the linear control during manufacturing and vertically matching the tower. Advance the conception of the accuracy control and build up an appropriate “Accuracy Control System” (ACS). Expound the contents of accuracy control, procedure and controlling means. Stress the research on the definition of the reference system of the tower, accumulated height error control, accumulated axis bias error control and accumulated torsion error control. Finally, in accordance with the results of accuracy control, give implement principle and method of manufacturing and vertically matching the tower. The check results show that accuracy of the control meets the design requirements and the research results are practical and reliable.

Abstract: In order to measure the water drainage volume in soil mechanical tests accurately, it develop a new method which is based on principles of optics. And from both physical and mathematic aspects, it deduces the mathematic relationship between micro change in displacement and the increment projected on screen. The result shows that total reflection condition is better than refraction condition. What’s more, the screen could show the water volume micro variation clearly, so it can improve the accuracy of measurement.

Abstract: The terrestrial laser scanner (TLS) is a line-of-sight instrument which can directly acquire dense 3D point clouds in a very short time. The registration method is used to act as a control point for a reflective target placed in overlapping areas in neighboring scanning stations. The main purpose for a reflective target is to be an obvious and precise positioning feature for laser scanning point cloud data. This study compares six common noise filtering methods which are used to eliminate measuring noise in the primitive point cloud of reflective target for better positioning accuracy, i.e. Scatter points removal method, Spikes removal method, Least squares plane method, Gaussian smoothing method, Median smoothing method, and the Average smoothing method. The test results found for 30, 60, and 90 meter distances in this study was that six noise filtering methods can actually increase the reflective target positioning accuracy, and the least squares plane method is the best one in either precision or accuracy. Beside the reflective target, the test is carried out with self-made targets for the comparison of positioning accuracy between the reflective target and self-made targets. Regarding accuracy, the reflective target is superior to the object in 30 and 60m, and self-made target is superior to the reflective target in 90m.

Abstract: GPS technology has penetrated into all fields of surveying and mapping disciplines,and has been widely used in leveling measurement .By studying the feasibility of the refining of region quasi-geoid based on the existing quasi-geoid,this paper shows a new method which is a combination of the Earth's gravity field model and the GPS leveling fitting method to determine the region quasi-geoid and provide the specific ideas and calculation steps and do analysis and discussion about the feasibility and superiority of this method using actual data.This new method makes full use of the advantages of the high resolution of the gravity geoid and the high-precision of the GPS geoid to realize the complementary strengths.