To overcome slow convergence velocity of Particle Swarm Optimization (PSO) which falls into local optimum easily, the paper proposed a new approach, a PSO algorithm using opposition-based learning and adaptive escape. The proposed algorithm divided states of population evolution into normal state and premature state by setting threshold. If popolation is in normal state, standard PSO algorithm was adopted to evolve; otherwise, it falls into "premature", the algorithm with opposition-based learning strategy and adaptive escape was adopted, the individual optimal location generates the opposite solution by opposition-based learning, increases the learning ability of particle, enhances the ability to escape from local optimum, and raises the optimizing rate. Experiments were conducted on 8 classical benchmark functions, the experimental results show that the proposed algorithm has better convergence velocity and precision than classical PSO algorithm, such as Fully Imformed Particle Swarm optimization (FIPS), self-organizing Hierarchical Particle Swarm Optimizer with Time-Varying Acceleration Coefficients (HPSO-TVAC), Comprehensive Learning Particle Swarm Optimizer (CLPSO), Adaptive Particle Swarm Optimization (APSO), Double Center Particle Swarm Optimization (DCPSO) and Particle Swarm Optimization algorithm with Fast convergence and Adaptive escape (FAPSO).
The domain concepts are complex, various and hard to capture the development of concepts in software engineering. It's difficult for students to understand and remember. A new effective method which extracts the historical evolution information on software engineering was proposed. Firstly, the candidate sets included entities and entity relationships from Wikipedia were extracted with the Nature Language Processing (NLP) and information extraction technology. Secondly, the entity relationships which being closest to historical evolution from the candidate sets were extracted using TextRank; Finally, the knowledge base was constructed by quintuples composed of the neighboring time entities and concept entities with concerning the key entity relationship. In the process of information extraction, TextRank algorithm was improved based on the text semantic features to increase the accuracy rate. The results verify the effectiveness of the proposed algorithm, and the knowledge base can organize the concepts in software engineering field together according to the characteristics of time sequence.
A bridge crack measurement system based on binocular stereo vision technology was proposed considering the low efficiency, high cost and low precision of bridge cracks measurement at home and abroad. The system realized by using some binocular stereo vision methods like camera calibration, image matching and three dimensional coordinates reconstruction to calculate the width and the length of bridge cracks. The measured results by binocular vision and by monocular vision system under the same conditions were compared, which show that using the binocular vision measurement system made width relative error keep within 10% and length relative error keep within 1% steadily, while the results measured by monocular vision were changed widely in different angles with a maximum width relative error 19.41% and a maximum length relative error 54.35%. The bridge crack measurement system based on binocular stereo vision can be used in practical well with stronger robustness and higher precision.
Since the face images might be not over-complete and they might be also corrupted under different viewpoints or different lighting conditions with noise, an efficient and effective method for Face Recognition (FR) was proposed, namely Robust Principal Component Analysis with Collaborative Representation based Classification (RPCA_CRC). Firstly, the face training dictionary D0 was decomposed into two matrices as the low-rank matrix D and the sparse error matrix E; Secondly, the test image could be collaboratively represented based on the low-rank matrix D; Finally, the test image was classified by the reconstruction error. Compared with SRC (Sparse Representation based Classification), the speed of RPCA_CRC on average is 25-times faster. Meanwhile, the recognition rate of RPCA_CRC increases by 30% with less training images. The experimental results show the proposed method is fast, effective and accurate.
Aiming at the problem that virtual-real registered accuracy and real-time performance are influenced by image texture and uneven illumination in Augmented Reality (AR), a method based on improved ORB (Oriented FAST (Features from Accelerated Segment Test) and Rotated BRIEF (Binary Robust Independent Elementary Features)) algorithm was proposed to solve it. The method firstly optimized the dense region of image feature points by setting the number and distance threshold of it and used parallel algorithm to reserve N points of greater eigenvalue; Then, the method adopted discrete difference feature to enhance the stability of uneven illumination changes and combined the improved ORB with BOF (Bag-of-Features) model to realize quick retrieval of Benchmark image. Finally, it realized the virtual-real registration by using the homographics between images. Comparative experiments among the proposed method, original ORB, Scale Invariant Feature Transform (SIFT) and Speed Up Robust Features (SURF) algorithms were performed from the aspects of accuracy and efficiency, and the proposed method reduced the registration time to about 40% and reached the accuracy more than 95%. The experimental results show that the proposed method can get a better real-time performance and higher accuracy in different texture and uneven illumination.
To tackle the higher requirement of mobile network for movie service system and the lack of description of movie domain knowledge, the necessity and feasibility of establishing the Movie Ontology (MO) were illustrated. Firstly, the objects and components of MO were summarized, and the principle and method for building the MO model were also put forward, with using the Web Ontology Language (OWL) and Protege 4.1 to build the model. After that, the concrete representation of the class, property, individual, axioms and inference rules in the MO were explained. Finally, the consistency of MO was analyzed, including the consistency analysis of relationship between classes and the consistency analysis based on axioms.
As standard Particle Swarm Optimization (PSO) algorithm has some shortcomings, such as getting trapped in the local minima, converging slowly and low precision in the late of evolution, a new improved PSO algorithm based on Gaussian disturbance (GDPSO) was proposed. Gaussian disturbance was put into in the personal best positions, which could prevent falling into local minima and improve the convergence speed and accuracy. While keeping the same number of function evaluations, the experiments were conducted on eight well-known benchmark functions with dimension of 30. The experimental results show that the GDPSO algorithm outperforms some recently proposed PSO algorithms in terms of convergence speed and solution accuracy.
In Dynamically Tuned Gyroscope (DTG) system, traditional identification methods, including least square identification method and traditional frequency domain identification method, could not achieve acceptable identification fitness degree. To deal with this problem, outlier-eliminated frequency identification method was proposed. In consideration of the characteristics of DTG model structure and intrinsic colored noise, outlier-eliminated method was applied to DTG frequency domain identification. The experimental results indicate that outlier-eliminated frequency identification method, with a fitness degree above 90%, compared with both least square identification method and traditional frequency domain identification method, has a better performance. In addition, outlier-eliminated frequency identification method possesses of good repeatability and stability. Outlier-eliminated frequency identification method could improve the identification fitness degree of DTG system.
For the control allocation problem of flexible fly-wing aircraft with multi-control surfaces, the machine vibration force index was put forward to measure the elastic vibration. Total control allocation model was established, the superior performance of the Estimation of Distribution Algorithm (EDA) was used for solving the model. Firstly the rudder structure was designed, the way of work and control capability of every aerodynamic rudder were analyzed, and the rudder functional configuration was built in accordance with the rudder control efficiency of redundant rudder, elevator aileron and aileron rudder in aerodynamic data. During the control allocation, main performance indices of control allocation were analyzed, the overall multi-objective optimal evaluation function was established, which combined with the equality and inequality constraints, and solved by EDA. The true distribution was estimated by establishing a probability model, during the evolutionary process of EDA, the rudder would be allocated according to the deflection efficiency, the optimal solution was got by combining with the optimization function. At last, the impact of aero wing flexibility on static control performance of the system was analyzed. After considering aeroelasticity, the overshoot and transition time are decreases. The flying quality of flying wing aircraft is significantly improved, the system efficiency is improved by at least 10% after optimization. The simulation results show that the EDA can better solve the control allocation problem, and can improve the dynamic quality of the system, verifying the effectiveness of multi-control surfaces to control allocation.