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Aiming at the problem that the Firefly algorithm (FA) is prone to fall into local extremum, low precision and slow convergence speed, an improved Firefly algorithm (OLLevyFA) based on reverse learning initialization and Levy perturbation mechanism is proposed on the basis of the Firefly algorithm (FA). Through the calculation of nine typical test functions, the FA algorithm, LevyFA algorithm and OLLevyFA algorithm compared and verified. The results show that compared with the FA algorithm, the LevyFA algorithm and the OLLevyFA algorithm can jump out of the local optimum more effectively, and the OLLevyFA algorithm has the characteristics of higher precision and faster convergence speed. Finally, the FA algorithm, LevyFA algorithm and OLLevyFA algorithm are put into the magnetization temperature measurement model. The comsol software is used to simulate the calculation results and the results of the particle swarm optimization algorithm. The results show that the results of OLLevyFA algorithm have higher precision and can meet the requirements of the system.

Analytical simulation is an important method to study CT reconstruction algorithm, which can quickly and effectively demonstrate the effectiveness and accuracy of the reconstruction algorithm. According to the basic process of CT detection and the main frame, which includes model generation, parallel beam scan projection data acquisition, common analytic algorithm of image reconstruction and image post-processing and analysis, the parallel beam CT analytical simulation software platform is developed by C++ language. The setup interfaces for main parameters of each link are reserved, so the key items of the simulation process can be selected and adjusted, which carries out a flexible simulation study based on the CT platform. Finally, an example of reconstruction simulation for tubular object based on angle sparse projection data from parallel beam CT is given, which verifies the practicability of the simulation software platform.

In this study we analyze the signal in measurement system with distributed optical fiber sensors. The display signal is defined by the user not for general custom. The data of for-processing-part are processed regularly, which directly provides results for the user from the monitoring system. These results go into the next step to add environmental parameters, which includes weather, special events and season information. Information fusion and matching operation of the result and environment information enhances the accuracy of hidden hazard early warning.

The integrated electro-hydrostatic actuator (EHA) with variable displacement and variable rotation speed is researched. In the system, the output of the actuator is changed by controlling the rotation speed of the brushless DC servomotor and the displacement of the servopump. The mathematical model described in state space model is created. The system characteristics are studied based on the point of multiplicative dual variable. And the basic method of control of the system is presented.

China is arguably one of the countries where the most tunneling and underground projects are being performed. Recently in China, it has often been necessary to construct tunnels under many types of conditions and to develop new techniques. Currently, some advanced construction techniques cannot be appropriately applied to different types of underground conditions, and many traditional methods are still often used. However, because of the progress in tunnel boring machines (TBM), innovations are required for the construction method. This article introduces the current situation of TBM both in western countries and in China, and examines the future of TBM in China.

In this paper, based on the mechanism of CCD camera, an event-based simulation method of γ-ray-induced transient noise was developed, which applying MCNP5 Code based on Monte Carlo methods. On the mono-energy γ-ray sources, the transient noises of two different CCD cameras have been measured at different doses (from 0.001mR to 1mR) and different incidence angles. The 60 Co and 137 Cs were used as the mono-energy γ-ray sources, and the Compton Scattering technique were adopted to get lower energy γ-ray sources. In order to get the pure transient noise induced by γ-ray, a method was advanced for extracting the transient noise from the image mixed the background noise. And the transient noise was characterized, including the number of noise clusters, the noise intensity spectrum and the size spectrum of noise clusters. The variation characteristics of noise have been draw from the simulation and experiment, which induced by γ-rays of different dose, or different energy or different incidence angle.