Aerodynamic responses of rectangular plates with different aspect ratios during flapping motion were simulated using a three dimensional unsteady panel code. The three-dimensional effects during plunging and pitching motions were then analyzed. The results demonstrated that the added mass only contributes to the instaneous lift force. The amplitudes of lift forces induced by added mass effects would decrease with a decreasing aspect ratio, but the time-averaged contributions were always zero. Vortices shedding from trailing and side edges of rectangular plates are sources of time-averaged lift forces. As the signature of streamwise vortices would change during one flapping cycle, the three-dimensional effects on vortex-induced lift forces would reduce as the flow unsteadiness increased.

The AOT (aerosol optical thickness) data, retrieved by the MODIS on Terra satellite, were compared with PM_2.5 mass concentration at Tsinghua University. It was shown that both AOT and PM_2.5 had obviously seasonal-change character, and the linear correlation coefficient between them was better in summer than in winter. After modifying weather conditions, such as RH and aerosol elevation, we always found a high correlation coefficient between AOT and PM_2.5. The present study suggests that MODIS AOT is an effective means for monitoring PM air quality.

A three-stepwise robust statistical method combining the robust statistical theory with distribution features of rainfall for detection of outliers in telemetry system is described. The proposed robust statistical method adopts the Tukey fence insensitive to outliers as identification bounds and presents a three-stepwise pattern to adapt the distribution of rainfall data. Moreover, the modified method based on dividing precipitation data into several groups further improves detection efficiency. The results show that the new method is suitable to the hydrological need.

This study used concentricity coefficients, disequilibrium coefficients, and ameliorative gravitation model approach to estimate the passenger and cargo fluxes in the recent years in Xinjiang. Then the results were fixed through qualitative analysis. The conclusions are as follows: (1)Disequilibrium coefficients are obviously different; (2)The node cities are also different, showing diverse trends; and (3)At the present, the city hierarchical system takes "Urumuqi-Changji" as center, "Kuytun-Usu" and Kashgar as subordinate centers, Shi Hezi, Bole, Korla, Aksu, and Fukang as regional centers, and the other cities as regional subordinate centers.

The new ship detection algorithm based on local K-distribution proposed in this paper uses a target window and a background window, removes the leaked ship pixels in the background window by using special methods, and estimates the remaining pixels in the background window to get the local clutter’s gray mean and variance. Then the local clutter’s gray probability distribution can be modeled to realize CFAR detection. Compared with K-distribution CFAR detector and local K-distribution CFAR detector, the new algorithm can fit the local change of the sea clutter and detect the targets which are too near. The simulation results show the effectiveness of the new algorithm.

A novel twisting-style switch matrix is proposed based on the research into architectures of traditional switch matrixes. By using the method of wire twisting, a single tileable switch cell can be replicated and abutted to form the layout of switch matrix. SPICE simulation demonstrates that the proposed switch matrix presents uniform delay characteristic and lower static power dissipation.

An audio steganalysis method based on wavelet packet and adaptive predictor is proposed. In this scheme, audio signals are firstly decomposed by the wavelet packet, the wavelet packet coefficients of high frequency are then predicted by the LMS adaptive predictor, statistics of predicted errors are selected as the statistical features, and finally SVM is implemented as a classifier. The experimental results verify that, for the commonly used steganography methods of additive noise, high classification accuracy can be achieved even in the case of low embedding strength or low embedding rate.

In order to provide large capacity of steganography and maintain a good visual quality of stego-video, a novel high capacity video steganographic algorithm based on visual perception model is presented. This algorithm integrates multi-parameter spatial contrast sensitivity function, contrast masking based on classification of DCT blocks, and motion attention. Then secret information is embedded under control of distortion masking measure of each DCT coefficient. Experimental results show that the new algorithm has ability to hide secret data of large capacity without noticeable distortion.

This study presents a radar monitoring and controlling system which is mainly based on the NiosII CPU and introduces the hardware integration and software design flow of the system on programmable chip. The kernel of design is Cyclone II family FPGA which supports the 32 bits high performance NiosII CPU, and application software is developed in NiosII IDE environment tool. Compared with the traditional monitoring and controlling system, the present design has capabilities of fast data transmitting, low power consumming, and high integration.

Phased array radar is the main direction in the development of airborne SAR, and the motion compensation system is essential to the airborne SAR system. By deploying the coordinate mapping method, the target beam under the earth coordinate system is mapped into the antenna platform coordinate system and converted to the antenna array element phase shift which controls the beam. The airborne SAR motion compensation is then implemented. The algorithm is implemented by using DSP and FPGA. The experimental results show that the designed hardware and software are reliable.

This paper designs and simulates a pointing mirror control system driven by permanent magnet synchronous motor (PMSM). The mathematical model of PMSM and space vector pulse width modulation are established and the corresponding simulation results are presented. Based on the model, a high accuracy controller which consists of current loop, velocity loop, and position loop is designed and simulated. Due to the inherent system uncertainties, various disturbances can affect the system accuracy. This paper proposes a position control scheme employing a feed-forward controller and a repetitive controller. Theoretical analysis and simulation experiments show that the designed pointing mirror control system has good dynamic characteristic with a short setting time, a fast dynamic response, and little position error.

The algorithm simulates the movement of fish shoal in the space. According to the Euclidean distance, the neighborhood of the fish individual is divided into attraction zone, repulsion zone, and neutral zone. Furthermore, the movement trend to the food source is considered. The neighborhood factors were determined by means of the experiments. The experiments were carried out on the benchmark functions for comparison of the Novel Fish-shoal Algorithm with the Artificial Fish-swarm Algorithm. The search step size was studied experimentally. Finally a linear change weight factor strategy was proposed and the experimental results with 13 test functions verified that the proposed strategy can further improve the performance of the algorithm.

In this paper, we formally built the security models on key privacy in the multi-recipient and randomness re-using multi-recipient setting and proved their security. Two associated reproducibility tests concerning key privacy were proposed. Based on these results, we constructed a general shortened private broadcast encryption scheme which approximately halves ciphertext overhead and computational cost.

This paper presents a new efficiency evaluation methodology of DoS attack and defense mechanisms based on queueing theory. The unified index system and evaluation algorithm were proposed for various types of DoS attack and prevention. We also built queueing models to do the quantitative assessment and analyze objectively the efficiency of UDP Flood and SYN Flood. Network simulation tools were used in typical DoS attack scenarios. The rationality of the queueing models is verified through comparison of the experimental data with the results derived by the models. In addition, the utilization of this evaluation method in efficiency comparison of different types of DoS attack and defense mechanisms is illuminated through examples.

A detection method for memory overrun is presented to overcome multi-loop problems: (1)identifies suspicious defects and their dependent regions; (2)analyzes multi-loops by CR# algebra; (3)infers probability of triggering defect and path guide information; (4)detects defects based on symbolic execution; and (5)finds defects, trigger paths, and program input. A prototype tool has been implemented, and it found real defects in several open source softwares. The results show that the new method can avoid blind path traversal while preserving path-sensitive and bit-level detection precision, and improve efficiency and veracity of defect detection.

There are two singularities in atmospheric governing equations under spherical coordinate system, and hence, velocity at the north and south poles can not be defined and predicted directly by grid-point atmospheric model. To solve this problem, a simple approach is presented, and an explicit square conservation scheme in A-grid for shallow water model is chosen as an example. The new approach defines pole velocity and sets up a difference equation. The new model can predict pole velocity directly, and the numerical experiment shows that the results are reasonable.

The angiotensinogen (AGT) gene polymorphism was detected in the study of 82 cerebral infraction (BI) cases, 67 simple essential hypertension (EH) cases, and 95 normal cases (control) using mutagenically separated PCR (MS-PCR) technique. The association of the AGT gene CD235Met-Thr variant and cerebral infraction (BI) in Chinese hypertension disease is evaluated. The frequencies of T/T genotype and T allele (0.720 and 0.811) in the BI group were significantly higher than those in the control group (0.516 and 0.700, P<0.05) and the EH group (0.537 and 0.716, P<0.05), respectively. These results suggest that the AGT gene CD235Met-Thr variant is significantly associated with Chinese hypertensive patients with cerebral infraction.

The present study proposes a method for hidden malcode detection based on the analysis of dynamic control-flow. First we recorded the malcode-related control-flow paths of program, and then the control-flow paths were analyzed, by calling tree match algorithm, to detect the hidden malcode in the system. The experiments show that this method can detect hidden malcode efficiently at a high detection rate and with low false positive, and thus it can be applied to malcode detection on operating systems.