Improving Neural Networks for Mechanism Kinematic Chain Isomorphism Identification

Detection of isomorphism among kinematic chains is essential in mechanical design, but difficult and computationally expensive. It has been shown that both traditional methods and previously presented neural networks still have a lot to be desired in aspects such as simplifying procedure of identification and adapting automatic computation. Therefore, a new algorithm based on a competitive Hopfield network is developed for automatic computation in the kinematic chain isomorphism problem. The neural approach provides directly interpretable solutions and does not demand tuning of parameters. We have tested the algorithm by solving problems reported in the recent mechanical literature. Simulation results show the effectiveness of the network that rapidly identifies isomorphic kinematic chains.     

基于FSG的最大频繁子图挖掘算法*

图挖掘已成为数据挖掘领域研究的热点,然而挖掘全部频繁子图很困难且得到的频繁子图过多,影响结果的理解和应用。可通过挖掘最大频繁子图来解决挖掘结果数量巨大的问题,最大频繁子图挖掘得到的结果数量很少且不丢失信息,节省了空间和以后的分析工作。基于算法FSG提出了最大频繁子图挖掘算法FSG-MaxGraph;结合节点的度、标记及邻接列表来计算规范编码,提出两个定理来减少子图同构判断的次数,并应用改进后的决策树来计算支持度。实验证明,新算法解决了挖掘结果太多理解困难的问题,且提高了挖掘效率。     

Low-temperature phase formation in the SrF2–LaF3 system

Phase formation in the SrF₂–LaF₃ system was studied at temperatures ranging from 300°C to 450°C using nitrate flux. The solubility of LaF₃ in SrF₂ decreases with decreasing temperature. The equilibrium width of the solid solution region Sr_1−xLa_xF_2+x at 400°C, it is 44.6 ± 0.4 mol% LaF₃ (x = 0.446), at 350°C — 38.3 ± 0.7 mol% LaF₃ (x = 0.383), and decreases almost to zero at 300°C.     

Ω-模糊软环

将软集理论的概念应用到Ω-模糊环中,提出了Ω-模糊软环的概念,给出了Ω-模糊软环的交与并的定义;探讨了交与并的一些相关性质;讨论了Ω-模糊软环的同态的一些性质,并提出了Ω-模糊软子环和模糊软同构的概念,研究了与其相关的性质。     

Region-Based Hierarchical Image Matching

This paper presents an approach to region-based hierarchical image matching, where, given two images, the goal is to identify the largest part in image 1 and its match in image 2 having the maximum similarity measure defined in terms of geometric and photometric properties of regions (e.g., area, boundary shape, and color), as well as region topology (e.g., recursive embedding of regions). To this end, each image is represented by a tree of recursively embedded regions, obtained by a multiscale segmentation algorithm. This allows us to pose image matching as the tree matching problem. To overcome imaging noise, one-to-one, many-to-one, and many-to-many node correspondences are allowed. The trees are first augmented with new nodes generated by merging adjacent sibling nodes, which produces directed acyclic graphs (DAGs). Then, transitive closures of the DAGs are constructed, and the tree matching problem reformulated as finding a bijection between the two transitive closures on DAGs, while preserving the connectivity and ancestor-descendant relationships of the original trees. The proposed approach is validated on real images showing similar objects, captured under different types of noise, including differences in lighting conditions, scales, or viewpoints, amidst limited occlusion and clutter.     

最大频繁子图挖掘算法研究

随着图的广泛应用,图的规模不断扩大,因此提高频繁子图挖掘效率势在必行。本文针对频繁子图挖掘所产生的庞大的结果集,提出了一个最大频繁子图挖掘算法MFME,从而极大地减少了结果集的数量。MFME使用了映射的思想将图集中的边映射到边表中并在此表上进行子图挖掘,有效地提高了算法的效率。实验结果表明,MFME的效率较经典算法SPIN有明显提高。     

两类非线性密码组件可重构研究与电路设计

为解决对称密码中s盒和非线性布尔函数（NBF）在实现密码专用处理器时采用异构化设计导致的资源浪费问题,提出一种类AESs盒和NBF的可重构电路结构方法。分析s盒问题中的原有非线性布尔函数模块（NBFM）,4-4、6-4的s盒电路能够提供更好的适配性,但不能很好地支持8-8的s盒电路。基于塔域分解理论,论证不同的类AESs盒电路差异在于输入前后的转换矩阵。采用混合基的方法将类AESs盒电路分解成GF （16）上的各个运算模块,并推导出模块比特级别表达式,在具体适配运算模块时采取门级实现、NBFM适配实现或对NBFM进行改进3种方案,实现类AESs盒和NBF的可重构电路。实验结果表明,该方法在不影响原有NBF功能的基础上,利用4个NBFM与22.7%的s盒电路面积即可实现一个完整的类AESs盒电路。     

基于ROBDD的布尔函数同构判定算法研究

布尔函数是密码体制设计与分析中一个不可缺少的工具,在布尔函数的应用中,判定两个布尔函数的同构问题具有广泛的需求,但是,判定布尔函数同构是NP-难问题,并且采取穷举法也将随着变量的增多,因极高的时间复杂度而使其难以实现.该文基于图的思想,提出了一种基于ROBDD(简化有序二元决策图)的布尔函数同构判定算法,其算法的复杂度...     

Efficient search of combinatorial maps using signatures

In this paper, we address the problem of computing canonical representations of n-dimensional combinatorial maps and of using them for efficiently searching for a map in a database. We define two combinatorial map signatures: the first one has a quadratic space complexity and may be used to decide an isomorphism with a new map in linear time whereas the second one has a linear space complexity and may be used to decide an isomorphism in quadratic time. We show that these signatures can be used to efficiently search for a map in a database.