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Recognition of substrates in cobalt crust mining areas can improve mining efficiency. Aiming at the problem of unsatisfactory performance of using single feature to recognize the seabed material of the cobalt crust mining area, a method based on multiple-feature sets is proposed. Features of the target echoes are extracted by linear prediction method and wavelet analysis methods, and the linear prediction coefficient and linear prediction cepstrum coefficient are also extracted. Meanwhile, the characteristic matrices of modulus maxima, sub-band energy and multi-resolution singular spectrum entropy are obtained, respectively. The resulting features are subsequently compressed by kernel Fisher discriminant analysis (KFDA), the output features are selected using genetic algorithm (GA) to obtain optimal feature subsets, and recognition results of classifier are chosen as genetic fitness function. The advantages of this method are that it can describe the signal features more comprehensively and select the favorable features and remove the redundant features to the greatest extent. The experimental results show the better performance of the proposed method in comparison with only using KFDA or GA.

In seafloor mining environments, ultrasonic detection is often used for underwater target recognition, and a large number of suspended particles reduce the recognition rate of single-classifier cob...

Since the suspended sediments have severe influence on acoustic radiated field of transducer, it is significant for sonar system to analyze the influence of suspended sediments on acoustic pressure in the seafloor mining environment. Based on the KZK (Khokhlov-Zabolotkaya-Kuznetsov) equation, the method of sound field analysis in turbid water is proposed. Firstly, based on the analysis of absorption in clean water and viscous absorption of suspended sediments, the sound attenuation coefficient as a function of frequency in the mining environment is calculated. Then, based on the solution of KZK equation in frequency domain, the axial sound pressure of transducer in clear water as well as turbid water is simulated using MATLAB. Simulation results show that the influence of the suspended sediments on the pressure of near field is negligible. With the increase of distance, the axial sound pressures of transducer decay rapidly. Suspended sediments seriously affect the pressure in far-field. To verify the validity of this numerical method, experiment is designed and the axial sound pressure of transducer with a frequency of 200 kHz and a beam width of 7.5° is measured in simulated mining experiment. The results show that the simulation results agree well with the experiments, and the KZK equation can be used to calculate the sound field in turbid water.

To get a deeper understanding of the relationship between the flat belt axial motion (FBAM) and the angles of rollers, a test rig was designed and some experiments were done. The belt axial position was measured though imaging processing. A special filtering procedure was proposed to eliminate the random and systematic errors. Base on the authors’ previous study, the normalized analytical FBAM model was given. By comparing the simulation and experimental results, the effectiveness of the analytical FBAM model was validated. The results also show the relationship between the FBAM and the belt transferring distance is independent of the belt transferring speed.

To improve the calculation accuracy of the wrap angles, which are key parameters for the estimation of the maximum torque of the belt system, the steady configuration of the belt was researched. The governing equations and boundary conditions of the belt steady configuration were proposed and the following factors were considered in the model: the centrifugal force, the bending stiffness and the gravity of the belt. The belt steady configuration can be solved through a proposed iteration method based on the built model. The results show the gravity of the belt plays an important role on the belt steady configuration. The wrap angles calculated from the steady configuration are much less than that from the traditional geometric analysis. Thus the maximum torque of the belt system could be overestimated in the traditional belt design theory. It is necessary to calculate the wrap angles by solving the belt steady configuration, especially for the long center distance, high speed belt system.

LANDIS Pro 7.0 model was used to simulate the dynamics of aboveground biomass of ten broadleaved tree species in the Xiao Xing' an Mountains area under current and various climate change scenarios from 2000 to 2200, and carbon content coefficients (CCCs) were coupled to cal- culate the aboveground carbon sequestration rates (ACSRs) of these species. The results showed that in the initial year of simulation, the biomasses and their proportions of Fraxinus mandshurica, Phellodendron amurense, Quercus mongolica, Ulmus propinqua, and Acer mono were relatively low, while those of Betula costata, Betula platyphylla, and Populus davidiana were higher. A trend of rise after decline occurred in ACSR for pioneer species in the mid and late periods of simulation years, but ACSRs for the other broadleaved tree species were considerably complex. The ACSRs of Q. mongolica and Tilla amurensis fluctuated in the ranges of -0.05-0.25 t · hm(-2) · 10 a(-1) and 0.16-1.29 t · hm(-2) · 10 a(-1) in simulation years, respectively. The ACSRs of F. mandshurica, U. propinqua, A. mono, and B. costata showed a trend of decline after rise in late simulation years. There were significant differences in ACSR for P. amurense and B. davurica among various climate change scenarios in the periods of 2050-2100 and 2150-2200, while no significant difference in ACSR for the other species would be detected. Difference of sensitivity of various species in ACSR for future climate scenarios in the Small Khingan Mountains area existed. However, the un- certainty of future climates would not yield significant difference in ACSR for most broadleaved tree species. Moreover, a time lag would exist in the process of climate change effects on temperate forest's ACSR.

Considering the complexity of ship systems, the global optimum design problem on anti-shock resistance of ship systems is analyzed in this paper. The investment on anti-shock resistance of ship systems is taken as optimum objective function, and anti-shock strength of equipments in system is taken as optimum variable. Then the relationship between investment and anti-shock ability of equipments and systems was preliminarily discussed in this paper. Based on the optimum design method between anti-shock investment and performance, three mathematic models of global optimization were built according to practical engineering situation. Furthermore, the numerical analysis method was summarized. At last, the shock-resistance of some a power system was optimized by the method presented in this paper.