Based on open source softwares of Computer Haptics, visualizAtion and Interactive in 3D (CHAI 3D) and Open Graphic Library (OpenGL), a virtual surgical system was designed for reduction of maxillary fracture. The virtual simulation scenario was constructed with real patients' CT data. A geomagic force feedback device was used to manipulate the virtual 3D models and output haptic feedback. On the basis of the original single finger-proxy algorithm, a multi-proxy collision algorithm was proposed to solve the problem that the tools might stab into the virtual organs during the simulation. In the virtual surgical system, the operator could use the force feedback device to choose, move and rotate the virtual skull model to simulate the movement and placement in real operation. The proposed system can be used to train medical students and for preoperative planning of complicated surgeries.
Applications such as information retrieval need a precise representation of text content while the representations using traditional topic model can only extract topic background and have no ability for a precise description. A new low-rank and sparse model was proposed to decompose text into a low-rank component which represents topic background and a sparse component which represents keywords. To implement this model, the topic matrix was defined, and Robust Principal Component Analysis (RPCA) was introduced to realize the decomposition. The experimental result on news corpus shows that the model complexity is 25 percent lower than that of Latent Dirichlet Allocation (LDA). In practical applications, the low-rank component reduces the features needed in text classification by 28.7 percent, which helps to reduce the dimension of features; And the sparse component improves the precision of information retrieval result by 10.8 percent compared with LDA, which improves the hit rate of information retrieval result.
To solve the problem of the regulation of badminton dynamic stable equilibrium, the particle influence coefficient method of feather piece was put forward. The method combined badminton quality models and quality feather piece, bending camber degree, angle of attack, and other related factors. The feather piece of particle influence coefficient was obtained by adjusting the height centroid which satisfied badminton dynamic stability requirements got by striking tilt minimum square. Compared with the traditional badminton dynamic stabilization which must depend on the experience accumulated for a long time, the badminton particle influence coefficient method of feather piece that was put forward by this paper formed a theoretical system. And it had less time consumption, high efficiency, etc. The numerical results show that the proposed method is correct and effective.
In this paper, to protect data integrity in data aggregation of Wireless Sensor Network (WSN), a secure and efficient data aggregation scheme was proposed, which was based on Dual-head Cluster Based Secure Aggregation (DCSA). By setting symmetric keys between nodes and using distributed authentication method, this scheme performed node authentication and aggregation simultaneously, as integrity-checking of child node was completed immediately in the process of aggregation. Also, by using the oversight features of red and black cluster head, this scheme could locate malicious nodes and enhance the capability of anti-collusion attack. The experimental results show that the proposed scheme ensures the same security level with DCSA, and this scheme is able to detect and discard erroneous data immediately. It improves the efficiency of integrity detection mechanism and it has lower network energy consumption.
The near-surface defects are hard to identify in ultrasonic phased array Non-Destructive Testing (NDT), thus a new intelligent identification method based on fractal theory was proposed to solve this problem. A box-counting dimension algorithm based on linear interpolation was described to calculate the box-counting dimension of 140 groups of ultrasonic A-Scan time domain signals. Then the distribution of box-counting dimension was analyzed using the statistical method. The experimental results show that ultrasonic A-Scan signal is obviously fractal and it is effective to analyze the A-Scan signal with the fractal approach. This method has the potential to identify near-surface defects since the values of the box counting dimension of defective signals are different from those of defective signals. As a result, the detection rate of near-surface defects can be improved and the omission rate caused by man-made factors can be reduced in ultrasonic phased array automatic testing.
The existing algorithms of Top-k query can not make full use of the powerful parallel throughput of Graphic Processing Unit (GPU) to timely return the query results. So, a segmented query algorithm based on Compute Unified Device Architecture (CUDA) model was proposed. By dividing the query process and using the strategy of segmented parallel process, the maximal calculation and comparison efficiency in query process could be obtained in this algorithm. The experimental results show that this algorithm has obvious performance advantages compared with four-thread parallel optimization algorithm on multi-core CPU. When the number of ordered lists is 6 and the traversal stride is 120, the optimal performance can be obtained which is 40 times faster than multi-core CPU algorithm.
To meet the requirements of the military and merchant marine radar simulation, and enhance the simulation reality of radar image, a real-time scan simulation approach based on sector-banded texture blending model was presented to simulate highly realistic radar echo image. In this method, Electronic Navigation Chart (ENC) was regarded as the resource data of the radar echo signal, and according to the principle of the radar echo, the sector-banded texture blending algorithm was proposed to replace the traditional radar image simulation method based on the pixel-scan model and generate the radar echo texture data. Based on that, the simulation models of the radar echo signal processing were presented to implement the basic functions of the marine radar, such as gain adjustment, sea clutter suppression and rain/snow clutter suppression. The experimental results show the proposed approach improves distinctly the efficiency and effectiveness of the radar echo simulation, and it is a promising means to address the problem of radar and Electronic Chart Display Information System (ECDIS) simulation.