To solve the problems of Web service composition and verification, a formal model was proposed based on the framework of category theory. Process Algebra was introduced into the framework to describe the external behavior of service component, establishing a formal semantic model for the architecture of Web service system. The service network was described with category diagrams, in which Web services were used as categorical objects, and the interactive and composition relationships between services were used as morphisms. On the basis of the formal definitions of service interface, Web service and service composition, a further analysis and discussion about the semantics of service composition and interaction was undertaken. The concepts on Web service substitutability and service request satisfiability were formally defined. The application research shows that the proposed framework enhances semantic description capabilities of Web service architecture.
To solve the low running speed problem of Knuth39 random number generator, a Knuth39 parallelization method based on Many Integrated Core (MIC) platform was proposed. Firstly, the random number sequence of Knuth39 generator was divided into subsequences by regular interval. Then, the random numbers were generated by every thread from the corresponding subsequence's starting point. Finally, the random number sequences generated by all threads were combined into the final sequence. The experimental results show that the parallelized Knuth39 generator successfully passed 452 tests of TestU01, the results are the same as those of Knuth39 generator without parallelization. Compared with single thread on Central Processing Unit (CPU), the optimal speed-up ratio on MIC platform is 15.69 times. The proposed method improves the running speed of Knuth39 generator effectively, ensures the randomness of the generated sequences, and it is more suitable for high performance computing.
For the problem of that the particle easily falls into local optimum when avoiding obstacles and cannot walk forward, the method of retreating the position of the local optimal particle to its historical best position and searching the feasible and optimal location in the 8-neighborhood of this position was proposed. The position which is nearest to the target and is not a barrier could be found by this method, then the particle was moved to it. Meanwhile, the global optimal position of current generation particle swarm could be found, and the location of each particle was set for this position to continue iteration. In the experiments for obstacle avoidance in grid map, the fact was found that when encountering obstacles, the particles fell into local optimum by the traditional methods, but particles could successfully avoid obstacles and arrive the end by using the improved algorithm. The improved algorithm was introduced into the 3D visual simulation system, in large map with many obstacles scenarios, the probability of falling into local optimum of the particle was reached to 50% which resulted in routing failure. After adding a circular slope to the obstacles for the further improvement of the algorithm, the probability of successful path-finding of the particle was increased to 83%. The experimental results show that the search ability of the improved algorithm is increased and it can effectively plan path in a complex scene.
Pre-positioning facilities for collecting tents held by communities is helpful to improve the efficacy of tents collection in post-earthquake relief. A problem for pre-positioning facilities that collect the tents held by commnities considering various earthquake scenarios was studied. A bi-stage stochastic programming model was formulated for the facility location problem. The model aimed at minimizing economic costs and time-related costs. Considering the effects of weights and other parameters on the solutions, five experiments were performed and analyzed. A case was used to verify the practicability of the developed model that located the facilities of tents collection from communities in Pudong New District, Shanghai. Finally, a scenario based on Ya'an earthquake was used to analyze the influence of parameters on the solution under such a certain scenario.
Aiming at solving the misplaced and mismatch problems when 3D hair attaches different head models in the reuse process, a 3D hair reusable method based on scalp layer feature points was proposed. Firstly, according to the data storage structure of the model file, the scalp layer was isolated from the hair model and the feature points were extracted. Secondly, combined with the 2D face image detection method, feature points of the range of hair root on head cortex were extracted. Then shift and zoom coefficients were calculated by the above mentioned feature points. Finally, the fitting process of scalp layer and head model was handled individually. Eventually the 3D hair was adapted to the target head model,which could keep hair styling information without loss. The effect of a close fit between the scalp layer and the head model was achieved. The experimental results show that the proposed method can effectively improve the reusability of 3D hair model, and it is not influenced by the restrictions of the hair model personality part and the distribution area.
The schemes to solve the high bit error problem in wireless networks were discussed. Aiming to improve the performance of TCP protocal in mobile environments, two typical TCP models of the pure end-to-end approaches, TCPW and TCP-Real, were researched. The pure end-to-end schemes have the advantage of preserving the end-to-end semantics of TCP protocol. Simulation results with different bit error conditions of these protocols reveal an evident improvement in terms of TCP performance in relative to others, especially when the bit error rate is high.