基于光电传感器电路的迷宫机器人设计

采用Freescale公司的MC9SDG128单片机进行控制,使用ROHM公司生产的发送接收一体化反射型光电传感器RPR220,设计了一种新型迷宫机器人.该迷宫机器人能够在程序中严格控制光电传感器的开关,同时用软件消除外界干扰,取得了很好的探测效果.     

Dual-key-binding cancelable palmprint cryptosystem for palmprint protection and information security

Biometric cryptosystems and cancelable biometrics are both practical and promising schemes to enhance the security and privacy of biometric systems. Though a number of bio-crypto algorithms have been proposed, they have limited practical applicability because they lack of cancelability. Since biometrics are immutable, the users whose biometrics are stolen cannot use bio-crypto systems anymore. Cancelable biometric schemes are of cancelability; however, they are difficult to compromise the conflicts between the security and performance. By embedded a novel cancelable palmprint template, namely “two dimensional (2D) Palmprint Phasor”, the proposed palmprint cryptosystem overcomes the lack of cancelability in existing biometric cryptosystems. Besides, the authentication performance is enhanced when users have different tokens/keys. Furthermore, we develop a novel dual-key-binding cancelable palmprint cryptosystem to enhance the security and privacy of palmprint biometric. 2D Palmprint Phasor template is scrambled by the scrambling transformation based on the chaotic sequence that is generated by both the user's token/key and strong key extracted from palmprint. Dual-key-binding scrambling not only has more robustness to resist against chosen plain text attack, but also enhances the secure requirement of non-invertibility. 2D Palmprint Phasor algorithm and dual-key-binding scrambling both increase the difficulty of adversary's statistical analysis. The experimental results and security analysis confirm the efficiency of the proposed scheme.     

Optimized element positions for prescribed radar cross section pattern of linear dipole arrays

Approximate closed‐form expression is derived for the scattering from dipole arrays based on the equivalent circuit theory. Then, a method is proposed for synthesis of dipole arrays to produce desired scattering pattern using genetic algorithm (GA). In the synthesis method, the element positions in an array are considered as the optimization parameter and the derived expression is used to evaluate the fitness function of GA. To assess the validity and efficiency of the proposed method, several linear dipole arrays are designed to obtain scattering pattern with low sidelobe level (SLL). A good agreement between the patterns calculated using the expression and simulated by FEKO validates the accuracy of the presented expression. In addition, the numerical results show that the maximum SLL of the scattering pattern is considerably reduced by optimization. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Experimental investigation and comparison of super‐wideband antipodal slot antennas

Three novel, super‐wideband antipodal slot antennas with different tuning stubs are studied and compared with each other. Smooth, half‐circular slot profile is used to improve the antennas' polarization purity and impedance bandwidth, and different tuning stubs are used to finely tune the antennas' radiation performance. As will be reported, low crosspolarization level, stable dipole‐like pattern, and flat gain performances can be obtained within an operation bandwidth of 6.3:1 by introducing a smooth antipodal slot structure and a cup‐shape tuning patch. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

An equivalent method for blasting vibration simulation

Due to the complicated blasting load, the diversified medium models and various constitutive relations of the rock mass, and a huge job for simulating blasting of multiple holes, it is very difficult and costly to simulate the blasting vibration accurately in numerical computation. This paper presents an equivalent simulation method so as to transform this complex dynamic problem into an approximate initial-boundary problem. The equivalent elastic boundary applied by the blasting load was developed for multiple holes according to the spatial distribution of rock damage around each blasthole. The equivalent mechanics process of the complex blasting load was performed through analysis of the expansion of the borehole volume, the growth of cracks, the movement of stemming and the outburst of detonation gases. In combination with the blasting excavation of the tailrace tunnel in the Pubugou Hydropower Station, particle vibration velocities in the surrounding rock at different distances from the explosion source were simulated by applying this equivalent method based on the dynamic finite element method. The comparison with field monitoring data indicates that this equivalent simulation method is applicable to predicting the far-field dynamic response of the ground subjected to blasting load, and the selection of rock mass properties near the equivalent elastic boundary has a significant impact on simulation results.     

Efficient evaluation of query rewriting plan over materialized XML view

The query rewriting plan generation over XML views has received wide attention recently. However, little work has been done on efficient evaluation of the query rewriting plans, which is not trivial since the plan may contain an exponential size of sub-plans. This paper investigates the reason for the potentially exponential number of sub-plans, and then proposes a new space-efficient form called ABCPlan (Plan with Automata Based Combinations) to equivalently represent the original query rewriting plan. ABCPlan contains a set of buckets containing suffix paths in the query tree and an automata to indicate the combination of the suffix paths from different buckets as valid query rewriting sub-plans. We also design an evaluation method called ABCScan, which constructs a unified evaluation tree for the ABCPlan and handles the evaluation tree in one scan of the XML view. In the evaluation, we introduce node existence automata to encode the structure of the sub-tree and convert the satisfaction of the ABCPlan into the intersection problem of deterministic finite automata. The experiments show that ABCPlan based method outperforms existing methods significantly in terms of scalability and efficiency.     

基于神经网络和遗传算法的锅炉燃烧建模与优化

通过对影响锅炉效率的物理量的分析,建立了以神经网络表示主要物理量之间关系的锅炉燃烧系统模型,并采用遗传算法对模型进一步优化,从而实现了对锅炉燃烧的优化.仿真结果表明,通过调整锅炉燃烧系统优化模型参数,该模型能够同时满足锅炉燃烧效率和降低污染物排放的要求,从而实现锅炉的节能低污.     

基于Silverlight的海洋环境监测信息平台设计与实现

遵循完整性、先进性和开放性的系统开发原则,系统采用VS.NET开发平台,利用微软最新的Silverlight 技术以及其核心的Deep Zoom图像处理技术,以电子海图为基础,设计实现了全新的海洋环境监测信息平台.该系统已成功应用于南通市海洋与渔业信息系统中,实际应用表明该系统运行稳定可靠,在行业中具有较好的应用推广价值.     

高边界精度和抗噪的均值漂移图像分割算法

Mean shift(均值漂移)算法核函数窗口的带宽目前仍没有一个统一的确定标准.对整体图像根据Canny算子提取的边缘方向信息分成3类子图,一类是规则边缘子图,由规则边缘像素组成;第2类为非规则边缘子图,由边界方向变化剧烈的边缘像素组成;第3类是非边缘子图,由区域内部平坦区域和噪声区域组成.规则边缘子图和非边缘子图采用大窗口使区域内部更为平滑,并使噪声区域达到更高的抗噪性能,非规则边缘子图用小窗口可保持更高的边界精度.实验采用金属断口图像进行分割,结果表明,针对不同子图采用不同核函数带宽的方法使分割后的金属断口图像边界更准确,抗噪性能也更强.