Applied Mechanics and Materials Vols. 321-324

Abstract: To achieve rapid target detection by GPR (Ground Penetrating Radar),the article introduces fractal dimension as the characteristic to describe the complexity of the one-dimensional discrete signal and puts forward an algorithm for rapid target detection by GPR. First, calculate the fractal dimension of signals at different points in the direction of the survey line and depth direction after wavelet transform processing to obtain the curve of fractal dimension on two directions. Finally, determine the suspicious region in the curve of fractal dimension based on the judgment criterion to fulfill target detection. The measured data testify that the method can achieve the rapid detection on a specific target in a certain context.

Abstract: Has been actively studied for vessels monitoring system, but most of that is aligned with the large vessels. In recent years, with the growth of the marine leisure industry, there is a growing demand for vessel monitoring and providing information system of small and medium-sized vessels such as greenleisure vessels. In this background, this paper was designed the remote monitoring system showing through smart terminals in remote data has been transferred from the 60ft green leisure vessels. These system will be able to create a demand for green leisure vessels by interconnecting the integration operated system of the green·leisure vessels.

Abstract: A novel design to biochip microarray instrument is use of linear motors, in preference to conventional rotary motors driving ball screw. Three ironless core linear servo motors direct drive the X, Y and Z-axis motion, Improve performance such as superior positioning accuracy, high-speed operation and increased efficiency. The whole configuration for new microarray printing instrument is designed. Furthermore, the structure of special linear motors is also designed detailedly. And the linear servo motor automation control technology is introduced in this paper.

Abstract: Porosity, porosity distribution, porous shape, porous size, thickness of shield, shield height &width, and shield orientation are the factors that influence the performance of porous wind shields. Among them, porosity is the most important factor in determining the performance of porous shields. However shield height & width have major impacts on the performance of shields. The remaining factors play less significant influences on the performance of the shield, but they remain researching interests to be further studied.

Abstract: Locality-sensitive hashing is a technique to allow approximate nearest search for large volume of data in a fast manner. Binary code locality-sensitive hashing distributes a data set into buckets labeled with binary code, where binary codes are determined by a set of hash functions. The binary hash codes play the role of partitioning the data space into subspaces. When close neighbors are placed around subspace boundaries, there are chances to fail in locating them. It requires to check neighboring buckets while finding nearest ones. The paper presents a technique to enhance the search performance by introducing the notion of extended boundary. It reduces the potential misses and the search overhead especially for the regions located at the double-napped corners. Keywords: locality sensitive hashing, data search, hashing, data analysis

Abstract: As a nondestructive testing method, the magnetic flux leakage (MFL) testing technique is widely used for the testing of surface and near-surface areas in ferromagnetic materials. The MFL field is influenced by parameters of defects, strength of excitation, sensor lift-off value and electromagnetic noises etc. A 2-D finite element method (FEM) simulation model is established in this paper to analyze the influence of lift-off values under the condition of mechanical vibration and electromagnetic noises. The distribution of the MFL field peak for different lift-off values and different depth defects is presented. The defect quantization errors caused by the mechanical vibration and electromagnetic noises are introduced to analyze the influence of lift-off values and electromagnetic noises. The best range of lift-off values can be determined from the results of error analysis. It is effective to improve the measuring accuracy in practical MFL testing.

Abstract: Underwater mooring platforms which anchored by the anchor and cable have a certain function of the platform mooring at a certain depth. In this paper, the motion model of underwater mooring system was built through analyseing the motion characteristics of the cable geometry and the force of the cable. And the motion simulation of underwater mooring platform with ocean current was done. The results show that the motion of underwater mooring platform is stable.

Abstract: A nonlinear dynamic model of a miniature Six-Rotor is presented. A 4 channels PID controller is designed to operate the under actuated and dynamically unstable system with 6 inputs. Driving forces of 6 rotors are divided into four components such as throttle, roll, pitch and yaw. The control algorithm is simulated with Design Optimization Toolbox in Matlab. After observing the corresponding responses of Euler angles, the altitude and the driving force for each motor, the simulation results show good performance.

Abstract: The disturbances in the landing process of carrier-based aircraft include deck movement and ship wake. To guarantee the security of landing process, the simulation and model are necessary for the disturbances, and the deck movement and ship wake should be analyzed as well. On the basis of analysis of disturbances, the disturbances can be catalogued into two types: deck movement and ship wake. Combining with the relevant instructions in the American Army Standard, the mathematical model of each disturbance is established. The simulations of the deck movement and ship wake are also shown in this paper, which can supply the reliable disturbances models for the design of the control system of carrier-aircraft landing process.

Abstract: The controlled autoregressive model is widely used to describe a dynamic process. In this paper, a series of new algorithms are proposed to estimate the models coefficients and to predict future change of the process. On the one hand, it is can be proved that these new algorithms are outlier-tolerant in the case that there are outliers in sampling series. On the one hand, these new algorithms are near to the optimal estimators and predictors separately in normal case.