Applied Mechanics and Materials Vols. 48-49

Abstract: This paper defines a new image feature called Harris feature vector, which is able to describe the image gradient distribution in an effective way. By computing the mean and the standard deviation of the Harris feature vector in a local image region, novel descriptors are constructed for line (curve) matching which are invariable to image rigid transformation and linear intensity change. Experimental evidence suggests that the novel descriptor for line (curve) matching performs well.

Abstract: Image classification poses challenges to retrieval technology. Though the Support Vector Machine (SVM) has been successfully applied to pattern recognition, its performance is limited by the feature space and parameters in the training process. Our work thus has two central themes. Construct the optimum feature space for training SVM from image features extraction by nonlinear dimensionality reduction based on manifold learning, and meanwhile establish the RBF kernel based SVM classifier by training with the best parameters with a global search capacity of the Quantum-behaved Particle Swarm Optimization (QPSO). Experiments show that our model not only improves the learning ability, but also significantly enhances the accuracy of image classification.

Abstract: Detecting network traffic anomaly is very important for network security. But it has high false alarm rate, low detect rate and that can’t perform real-time detection in the backbone very well due to its nonlinearity, nonstationarity and self-similarity. Therefore we propose a novel detection method—EMD-DS, and prove that it can reduce mean error rate of anomaly detection efficiently after EMD. On the KDD CUP 1999 intrusion detection evaluation data set, this detector detects 85.1% attacks at low false alarm rate which is better than some other systems.

Abstract: To solve the efficiency issue of dedicated bus lanes (DBL), a time division multiplexing (TDM) method of DBL is proposed that the general vehicle can share DBL and avoid collision with the bus according to its GPS location. To harmonize the running of the bus and the general vehicle, a method is raised to divide space segment and time slice of DBL. At last, the PARAMICS simulating experiment shows the proposed DBL multiplexing approach could not only ensure bus priority but also promote the higher traffic speed, the lower traffic density and the shorter delay time of downstream intersection than before.

Abstract: In this paper, a novel adaptive waveform selection method is proposed for radar target tracking. In order to minimize the target state estimation MSE (Mean Square Error) on each tracking step, we adjust the PRI (Pulse Recurrence Interval) and pulse width of the emission signal with the constraint of average power. In this method, the position measurement CRLB (Cramer-Rao Lower Bound) is used to define the observation noise power, and then the relationship between the tracking performance and the waveform parameters is established to decide the optimal PRI. Simulations show that this method can improve the tracking accuracy effectively and dynamically.

Abstract: The aircraft sudden failures seriously affect the flight safety of aircraft, and the revelation of the evolution mechanism of aircraft sudden failures is of far reaching importance to the realization of evolution law of sudden failure, and the improvement of the safety and reliability of aircraft. By utilizing the dissipative structure theory, this paper carries out the analysis and research on the characteristics, causes and conditions of aircraft sudden failures from the perspective of mass and energy conversion. Moreover, it also targets on the engine surge, proposes the anti-surge monitoring program by taking the surge margin as monitoring parameters, and verifies the effectiveness and feasibility of proposed method through simulation and actualization.

Abstract: With the optimization design method of FE,the FE model of vertical flange lathe beam of double-tool holder was established,the sensitivity analysis of dynamic performance for the machine tool was performed based on presented modal analysis and probability analysis.The influence rules of the first four natural frequencies affected by the design parameters of the lathe beam were confirmed and the weaknesses of it were indicated as well.Then, the structure of the lathe beam was optimized.As a result ,the dynamic performances of the lathe beam are improved and it offers the basis for the optimization design of the other lathe parts.

Abstract: An effective rescheduling method takes an important role on improving the operational performance of a semiconductor wafer fabrication facility (fabs). In this paper, we propose a rescheduling method based on swarm intelligence. Firstly, we build a swarm intelligence based rescheduling model (SIRM) including an ant queen agent, multiple job ant agents and machine ant agents. Secondly, we design a rescheduling algorithm (CMRA) composed of three sub-algorithms: sub-algorithm-1 is used by an ant queen agent to transfer an existing static optimized scheduling plan into additional pheromones of job ant agents; sub-algorithm-2 and sub-algorithm-3 are used to convert scheduling related real-time information to dynamic pheromones of job ant agents and machine ant agents, respectively. Finally, a simplified semiconductor wafer fab model is used to verify and validate CMRA. The simulation results demonstrate that CMRA is superior to the original scheduling method to generate a static optimized scheduling plan with better performance on move, step and on-time operational due date rate under uncertain production environments.

Abstract: A new asynchronous wrapper circuit is proposed based on standard cells for the realization of point to point high speed seamless data transmission. The wrapper is realized from the Signal Transition Graph (STG) by Petrify based on the fundamental GALS system structure. The asynchronous circuit includes the design of synchronous/asynchronous interface and local clock which can be suspended. The traditional EDA tools are merged together with asynchronous circuit design, and the wrapper only has standard cells but not special asynchronous logic gates. The simulation and verification were made by Modelsim and Quartus respectively, and the results have shown that the GALS system works properly and has a preferable performance.

Abstract: So far, the research about sediment ablation characteristic of the Yellow River is very insufficiency. For preventing and alleviating sediment ablation of the Yellow River stations by more scientific methods, it is very necessary to research ablation characteristic of hydraulic turbine systematically. The ablation characteristic of hydraulic turbine has direct relation with sediment size distribution. By research ablation of hydraulic turbine material under different sediment size distributions, the common rules are summarized between material ablation and sediment size distribution, and the key data and critical parameters are found out, which provides evidence for sediment ablation defend of hydraulic turbine.