Site selection for a measuring and controlling device of initial phase based on maximum elevation angle

We introduced a site selection method based on the modified maximum elevation angle intended for mountains possibly affecting the measurement and control of the initial phase in a launching port located in mountainous areas. To use the former analysis results, the method, along the helices whose center is the launcher's project point, analyze each point's visibility on the helices. The visible area can be obtained by comparing the visibility at each moment in the initial phase. Finally, there can be three points in the above visible area with distances longer than required.     

An edge detection method based on a good point set genetic algorithm

In order to improve the convergence rate of genetic algorithms based on edge detection, a novel edge detection method based on a good point set genetic algorithm (GGA) was proposed. The proposed method designed the crossover operation with the theory of good point set in which the progeny inherits the common genes of the parents which represent its family so as to improve the convergence rate of the genetic algorithm. Furthermore, before the algorithm was used for edge detection, the feature space of the image grey level was transformed into the feature space of the fuzzy entropy. Dissimilarity enhancement processing next was applied to the image by using a fuzzy entropy theory to filter the non edge pixels so as to reduce the scale of the solution domain. This approach offered another efficient way to improve the convergence rate. Experimental results show the proposed algorithm performs very well in terms of convergence rate. The detected edge image is well localized, thin, and robustly resistant to noise.     

Simulation and experimental study of the fire performance of underground shopping streets

Underground streets have been developed in cities with land shortages. We simulated the dynamic distribution characteristics of smoke flow and temperature from fires under natural conditions in underground streets. The experiment was carried out at the Sichuan Fire Research Institute of Public Security Ministry, P.R. China. A 500 kg fire source was used in a real underground street. Temperature distribution at different heights and personnel escape routes are shown in two typical sections. The comparison between the computer simulation data and experimental data validates the simulation. This study provides a valuable reference for fire assessment of underground shopping streets.     

Influence analysis of fuel quality on engine emission performance

Quality, composition, and characteristics of fuel from 7 areas of P. R. China were analyzed. Fuel quality factors influencing engine emission performance were studied. Using fuel from the HuaZhong and XiNan areas, engine COx, HC, and NOx emissions were tested by adjusting the excess air coefficient and the advanced ignition angle. In light of the characteristics of aromatic hydrocarbon and alkenes of fuel from different areas in P. R. China, we have shown engines can operate smoothly and engine emissions can be decreased when the excess air coefficient and the advanced ignition angle are properly adjusted.     

Numerical simulation of the flow and temperature fields in an automotive exhaust muffler

By building a model of a typical exhaust muffler structure, a grid mesh was formed based on the calculation characteristic of the flow field. The software ANSYS CFX then was used to numerically simulate the flow and temperature fields in a muffler. The effects of the gas velocity and temperature variation on sound elimination performance, including the acoustics and aerodynamics performance, were analyzed. The result suggests that high velocity turbulence and high speed flow should be eliminated from muffler structures when designed. At the same time, to provide satisfactory noise elimination, pressure loss should be reduced as far as possible. The pressure loss can be decreased when reducing the perforation structure.     

Design of an electric parameter measurement instrument for power generation equipment

Because electric parameters are crucial for indicating the operating condition of power generation equipment, an intelligent instrument for electric parameters measurement of power generation equipment was developed. A Hanning windowing interpolation algorithm based on FFT and a hardware frequency track were adopted to reduce the effect of leakage and fencing. In addition, a high speed AD conversion based on an external bus interface, a multiple feedback filter, an application of μC/GUI, and a multitask scheduler all were designed to improve timing and anti jamming. Test results indicate the system is stable and easily operated. The measured relative error of electric parameter is less than 0.5%.     

diagnosis method for gear equipment by sequential fuzzy neural network

This paper proposed a new method called a “sequential fuzzy neural network” to diagnose gear equipment failures automatically and precisely. The symptom parameters in time domain, by which each gear equipment failure can be detected sequentially, were selected according to values calculated from the signals measured in each gear condition. To express the relationship between the gear condition and the symptom parameters, the probability density functions were translated to possibility distribution functions by possibility theory. The diagnostic process can be carried out automatically by a neural network combined with sequential fuzzy inference. Examples of practical diagnosis are shown to verify the efficiency of this method.     

analysis and application of demand forecasting model with multi element variable parameters

A forecasting model for logistics demand was presented to overcome the limitations of single goal forecasts of logistics demand and forecast data complexity. Based on the forecasting evaluation index and pretreatment of rough set theory, a multi input and multi output wavelet network (MMWNN) model for forecasting multi element regional logistics demand was studied. The network configuration was confirmed using the stepwise checkout and iterative gradient descent methods. After rough set reduction, the evaluation index was used to forecast the multi element regional logistics demand. The results of the numerical example indicate the feasibility and effectiveness of the model.     

A corrosion diagnosis method for optimized measurement of grounding grids

Simulated experiments of grounding grid corrosion were conducted based on two 220 kV substation models. In initial diagnosis, the measurement nodal points were planned to great span, small piecemeal, and large piecemeal jointing fixed points. A comparative study of the three measurement plans was carried out. The results show that the large piecemeal with fixed points had the best performance and could be used as a practical method for diagnosing grounding grid corrosion.     

Theoretical Analysis and Testing of Ground Treatment Using an Expansive Method in Very Thick Collapsible Loess

Through technological research of foundation treatments in the collapsible loess areas, we recommend a method of treating foundations in collapsible loess with quicklime piles. We set forth the basic principle of this expansive method. When a very thick foundation in collapsible loess is treated, the computational formula for the volume of expanding material in a quicklime pile is deduced based on cavity expansion theory. This theory is applied to engineering practice. Physical and mechanical properties of the compacted soil are tested. The result shows that the collapsibility of a foundation in loess has been eliminated, its physico mechanical indexes have been improved, and the soil compressibility and the modulus of compressibility also increase remarkably, demonstrating the correctness of the computation theory. The feasibility of the expansive method for very thick collapsible loess areas is further established.