BCB中重构字符在位图上的显示技术

简述了以C＋＋Builder为开发工具控制字符在位图上的显示形式。     

Algorithms for pattern matching

This paper describes four algorithms of varying complexity used for pattern matching, and investigates their behaviour. The algorithms are tested using patterns of varying length from several alphabets. It is concluded that although there is no overall ‘best’ algorithm, the more complex algorithms are worth considering as they are generally more efficient in terms of number of comparisons made and execution time.     

Spelling correction using probabilistic methods

A probabilistic procedure is suggested for the automatic correction of spelling and typing errors in printed English texts. The heart of the procedure is a probabilistic model for the generation of the garbled word from the correct word. The garbler can delete or insert symbols in the word or substitute one or more symbols by other symbols. An expression is derived for $\text{P(Y ? X)}$, the probability of generating a garbled word Y from a correct word X. The model is probabilistically consistent. Using the expression for $\text{P(Y ? X)}$, we can derive an estimate of the correct word from the garbled word Y so as to minimize the average probability of error in the decision. One of the important features of the expression $\text{P(Y ? X)}$ is that it can be computed recursively. Experiments conducted using the dictionary of 1025 most common English words indicate that the accuracy of correction by this scheme is substantially greater than that which can be obtained by other algorithms especially while dealing with garbled words derived from relatively short words of length less than 6.     

3-Dimensional curve similarity using string matching

In this paper, we present a new approach to measuring the similarity between 3D-curves. Our approach allows the possibility of using strings, where each element is a vector rather than just a symbol. We present two different approaches for representing 3D-curves. One possibility is to represent a 3D-curve as two 2D-curves, one being the projection of the 3D-curve in the XY-plane, and the other one in the YZ-plane. For the case that we need geometric rotation invariance, we have used a second approach to the symbolic representation of the 3D-curve using the curvature and the tension as their symbolic representation. We validate this approach through experiments using synthetic and digitalized data.     

短时公交客流的弦不变量预测方法

短时公交客流预测是智能公交系统动态调度的基础.文中根据短时公交客流数据特性,提出基于弦理论的短时公交客流预测方法,模拟弦结构建立弦不变量客流预测模型(SI-PFPM),并采用遗传算法优化SI-PFPM中各参数.提出基于动态时间弯曲距离的仿射传播(AP)聚类算法,对短时公交客流时间序列进行聚类分析.利用SI-PFPM预测聚类子集数据,并分析预测残差,验证SI-PFPM可以预测短时公交客流的假设成立.最后将SI-PFPM的预测性能与现有方法进行对比分析,验证SI-PFPM对短时公交客流预测的有效性.     

Leader tracking in homogeneous vehicle platoons with broadcast delays

For vehicle platoons, the leader following control architecture is known to be capable of achieving string stability while maintaining tight formations. In this paper, we study a variety of schemes where the leader state is available to the other members of the platoon. We show that in some cases it is possible to achieve string stability in the presence of certain amounts of time delay in the leader state reception. We also compare other properties of the different schemes and discuss some of their advantages and disadvantages.     

一种字符串压缩全模式匹配的主机入侵防御算法

针对现有名单匹配算法由于对名单中文件路径使用明文保存方式存在安全隐患,提出一种基于字符串压缩的用于全模式匹配的名单匹配算法。首先对保存有文件全路径的字符串进行MD5运算,然后将MD5值与压缩处理成16个字节的二进制路径数据合并进行求模运算,最终将名单元素转化成一个32字节结构体。通过仿真实验对朴素匹配算法、BM、压缩三种算法在内存使用、遍历时间、查找时间以及重复数上进行比较,实验结果表明,所提出的算法在性能以及安全性上优于其他算法。     

An example for the switching delay feedback stabilization of an infinite dimensional system: The boundary stabilization of a string

For vibrating systems, a delay in the application of a feedback control may destroy the stabilizing effect of the control. In this paper we consider a vibrating string that is fixed at one end and stabilized with a boundary feedback with delay at the other end.We show that certain delays in the boundary feedback preserve the exponential stability of the system. In particular, we show that the system is exponentially stable with delays freely switching between the values 4L/c and 8L/c, where L is the length of the string and c is the wave speed.     

Cache-oblivious index for approximate string matching

This paper revisits the problem of indexing a text for approximate string matching. Specifically, given a text T of length n and a positive integer k, we want to construct an index of T such that for any input pattern P, we can find all its k-error matches in T efficiently. This problem is well-studied in the internal-memory setting. Here, we extend some of these recent results to external-memory solutions, which are also cache-oblivious. Our first index occupies O((nlog^kn)/B) disk pages and finds all k-error matches with O((|P|+occ)/B+log^knloglog_Bn) I/Os, where B denotes the number of words in a disk page. To the best of our knowledge, this index is the first external-memory data structure that does not require Ω(|P|+occ+poly(logn)) I/Os. The second index reduces the space to O((nlogn)/B) disk pages, and the I/O complexity is O((|P|+occ)/B+log^k(k+1)nloglogn).