In order to investigate the simplified method for the fire resistance analysis on the steel staggered-truss system (SSTS) under the lateral force, a three-dimensional (3-D) model, a plane cooperative (PC) model and a planar model are established by the finite element method respectively. The effect of slabs is considered in the models. The mechanical performances of SSTS at elevated temperature were analyzed and the interaction characteristics between the truss exposed to fire and its adjacent trusses are studied. The results obtained by the above different models were comparatively investigated to explore the applicability of different models for the analysis of SSTS under lateral force and high temperature. The results indicate that the adjacent trusses in SSTS under lateral force could keep good coordination at elevated temperature. When applied to the analysis for SSTS under lateral force at elevated temperature, the 3-D model is the best in accord with actual situation while it is complicated and the computation is time-consuming, and the planar model is simple and convenient while it may cause some considerable deviation, and the PC model could simulate the interactions between adjacent frame truss and the truss under fire effectively in the SSTS, whose result is in the propinquity of 3-D model and has an acceptable accuracy. The PC model without rigidly hinged bars (RHB) on the fire floor is recommended to analyze the fire response behaviors of staggered-steel truss system under lateral force.

A decomposition-based optimization algorithm was proposed for solving Earth Observation Satellites scheduling problem. The problem was decomposed into task assignment main problem and single satellite scheduling sub-problem. In task assignment phase, the tasks were allocated to the satellites, and each satellite would schedule the task respectively in single satellite scheduling phase. We adopted an adaptive ant colony optimization algorithm to search the optimal task assignment scheme. Adaptive parameter adjusting strategy and pheromone trail smoothing strategy were introduced to balance the exploration and the exploitation of search process. A heuristic algorithm and a very fast simulated annealing algorithm were proposed to solve the single satellite scheduling problem. The task assignment scheme was valued by integrating the observation scheduling result of multiple satellites. The result was responded to the ant colony optimization algorithm, which can guide the search process of ant colony optimization. Computation results showed that the approach was effective to the satellites observation scheduling problem.

Thanks to the exceptionally good properties in chaotic systems, such as sensitivity to initial conditions and control parameters, pseudo-randomness and ergodicity, chaos-based image encryption algorithms have been widely studied and developed in recent years. Standard map is chaotic so that it can be employed to shuffle the positions of image pixels to get a totally visual difference from the original images. This paper proposes two novel schemes to shuffle digital images. Different from the conventional schemes based on Standard map, we disorder the pixel positions according to the orbits of the Standard map. The proposed shuffling schemes don’t need to discretize the Standard map and own more cipher leys compared with the conventional shuffling scheme based on the discretized Standard map. The shuffling schemes are applied to encrypt image and disorder the host image in watermarking scheme to enhance the robustness against attacks. Experimental results show that the proposed encryption scheme yields good secure effects. The watermarked images are robust against attacks as well.

Cluster synchronization is investigated in different complex dynamical networks. Based on an extended Kuramoto model, a novel approach is proposed to make a complex dynamical network achieve cluster synchronization, where the critical coupling strength between connected may be obtained by global adaptive approach and local adaptive approach, respectively. The former approach only need know each node’s state and its destination state; while the latter approach need know the local information. Simulation results show the effectiveness of the distributed control strategy.

Joint is among the most important factors in understanding and estimating the mechanical behavior of a rock mass. The difference of the strength, deformation characteristic of joint will lead to different strength and deformation of rock mass. The direct shear test is very popular to test the strength of joint owing to its simplicity. In order to study the three dimensional characteristic of joint, the numerical simulation software FLAC3D is used to build the calculation model of direct shear test under both loads in normal and shear direction. Deformation and mechanical response of the joint are analyzed, showing that, (1) relationship between shear strength and normal stress meets the linear Mohr-Coulomb criterion, the results are similar with that from the laboratory test; (2) the distribution of stress on the joint increases from the shear loading side to the other; and with the increase of normal stress, the distribution of maximum shear stress does not change much. The analysis results can give some guidance for the real practice; (3) the result from the numerical modeling method is close to that from the laboratory test, which confirms the correctness of the numerical method.

Considering the properties of remote sensing texture such as strong randomness and weak local correlation, a novel adaptive compression method based on vector quantizer is presented and implemented on GPU. Utilizing the property of Human Visual System (HVS), a new similarity measurement function is designed instead of using Euclid distance. Correlated threshold between blocks can be obtained adaptively according to the property of different images without artificial auxiliary. Furthermore, a self-adaptive threshold adjustment during the compression is designed to improve the reconstruct quality. Experiments show that the method can handle various resolution images adaptively. It can achieve satisfied compression rate and reconstruct quality at the same time. Index is coded to further increase the compression rate. The coding way is designed to guarantee accessing the index randomly too. Furthermore, the compression and decompression process is speed up with the usage of GPU, on account of their parallelism.

Volume rendering is an important and effect algorithm to represent 3D volumetric data and 3D visualization on electromagnetic environment (EME) is one of the most important research fields in 3D battlespace. This paper presents a novel framework on visualizing the 3D EME by direct volume rendering on virtual globe. 3D power volumetric data is calculated based on the Longley-Rice radio propagation model (Irregular Terrain Model, ITM), which takes into account the effects of irregular terrain and atmosphere, and we use GPU-accelerated method to compute the EME volumetric data. The EME data are rendered using direct volume rendering method on virtual globe by assigning different color and opacity depending on user’s interactive input with color picker. We also propose an interactive method to show detailed information of EME at given place. This approach provides excellent decision supporting and plan-aiding for users.

Only by means of XOR operation, a novel image encryption scheme is proposed based on a nonlinear chaotic map (NCM). There are two rounds in the proposed image encryption scheme. In each round of the scheme, the pixel gray values are modified from the first pixel to the last pixel firstly, and then the modified image is encrypted from the last pixel to the first pixel in the inverse order. In order to accelerate the encryption speed, every time NCM is iterated, n (n>3) bytes random numbers which are used to mask the plain-image can be gained. And to enhance the security, a small perturbation will be given to the parameters of the NCM based on the last obtained n bytes modified elements before next iteration. Experimental results and theory analysis show that the algorithm has a high security performance and a good efficiency.