改进的二分法查找

当前有很多的查找算法,其中在对有序数列的查找算法中二分法查找（binary search）是最常用的。利用二分法,在含有n个元素的有序数列中查找一个元素的最大比较次数为[logn]＋1。在很多情况中,在查找之前有序数列分布的很多信息为已知,比如说如果知道了有序数列中每相邻两个元素之差的最大值的一个上界,就可以有比二分法更加有效的查找算法。文章给出了一个称之为改进的二分法查找算法。改进的二分法查找性能明显优于二分法查找,受数列分布的影响,其最坏情况下查找一个元素的最大比较次数在1和[logn]＋1之间,明显优于二分查找的[logn]＋1。在实际应用中利用改进的二分法可以极大地提高查找效率。     

基于概念的折半查找算法

自顶向下或自底向上两种标准查找方式不适合于具体领域逻辑,且缺乏灵活性.模拟有序数组中的折半查找,提出逻辑空间上的折半查找方法,证明该查找方法在保持完备性和非冗余性的同时,还提供了更好的灵活性,最后给出了该查找的通用算法,并分析其复杂性.     

多语种二分查找类库及文件生成工具的实现

该文,为了满足汉维机器翻译系统、汉维词典、维文字转换等系统中对文件的快速访问,使用C#设计与实现了基于二分查找的检索类和该类可访问的文件生成工具。     

Delayed Binary Search, or Playing Twenty Questions with a Procrastinator

Abstract. We study the classic binary search problem, with a delay between query and answer. For all constant delays, we give matching upper and lower bounds on the number of queries.     

约瑟夫环经典问题的几种算法比较

约瑟夫环是数据结构中一个经典问题.通过解决约瑟夫环问题.可以熟悉掌握顺序表和链表的数据结构和相关运算,对提高教据结构的应用能力大有裨益.给出约瑟夫环的几种算法,讨论不同存储结构下实现的约瑟夫环算法.并从空间复杂度和时间复杂度进行了算法比较.     

A q -Analogue of the Path Length of Binary Search Trees

A reformulation of the path length of binary search trees is given in terms of permutations, allowing us to extend the definition to the instance of words, where the letters are obtained by independent geometric random variables (with parameter q ). In this way, expressions for expectation and variance are obtained which in the limit for q→1 are the classical expressions. Received June 6, 2000; revised October 14, 2000.     

GSA: A Gravitational Search Algorithm

In recent years, various heuristic optimization methods have been developed. Many of these methods are inspired by swarm behaviors in nature. In this paper, a new optimization algorithm based on the law of gravity and mass interactions is introduced. In the proposed algorithm, the searcher agents are a collection of masses which interact with each other based on the Newtonian gravity and the laws of motion. The proposed method has been compared with some well-known heuristic search methods. The obtained results confirm the high performance of the proposed method in solving various nonlinear functions.     

基于搜索论的一种机器故障查找模型

机器故障查找是机器维修的一个重要环节,在搜索论的基础上提出了一种机器故障查找模型,利用启发式贪 婪算法求解该模型,并进行了实际数据验证。实验结果表明了利用该模型的     

全文检索模型的检索性能研究

对比研究了多种全文检索模型,实现了相应的系统原型,并通过实验对模型的检索性能进行了验证,为检索模型的选择与检索性能优化提供参考。     

求解蛋白质结构预测问题的局部搜索算法

蛋白质结构预测问题是计算生物学领域的核心问题之一。通过理论计算的方法根据蛋白质氨基酸序列直接预测其空间结构是解决这一问题的有效途径。构造了新的邻域结构，采用了部分随机跳坑策略，对此问题提出了新的局部搜索算法。计算结果表明，该算法计算效率要优于传统的遗传算法和Monte Carlo方法。对于链长为50的算例还找到了文献中所没有的全新的最低能量构形。     

网上信息搜索技术与搜索引擎

随着Internet在全球范围内的迅速兴起,面对纷繁复杂的Web空间,如何在浩翰如海的信息空间里快速找到并取得所需的信息,便成为人们所关注的主要问题。搜索引擎的出现,极大地方便了Internet用户,使快速有效地获取信息成为可能。目前网上搜索引擎各种各样,有Yahoo!、Excite、AltaVista、Lycos、Infoseek、OpenText、WebCrawler、WWW Worm等几十种。     

Windows环境下的禁忌搜索法解Job—shop问题

本文应用禁忌搜索算法来解决复杂的车间调度问题,介绍了禁忌搜索算法的基本概念和各项参数,讨论了基于禁忌搜索的调度方案,并给出了调度方案的编程实现。     

鱼群算法求解无人机任务规划问题

无人机任务规划问题是一个NP难问题,文中提出了一种带禁忌算子的鱼群算法对该问题进行求解.鱼群算法是在群体智能行为研究基础上提出的一种新型仿生优化算法,该算法根据"水域中鱼生存数目最多的地方一般就是该水域中富含营养最多的地方"这一特点来模拟鱼群的觅食行为以实现全局最优.文章在基本鱼群算法FSA的基础上,结合禁忌搜索的思想,对基本鱼群算法中的三种行为算子进行改进,在每种行为算子中增添对解领域的禁忌搜索规则,提出带禁忌算子的鱼群算法(FSAWTS).然后将该算法应用于无人机任务规划问题.仿真试验表明,与基本鱼群算法相比,改进后的鱼群算法能够更为有效得解决无人机任务规划问题.     

具有邻域搜索机制的爆炸搜索算法

受烟花(炸弹)爆炸的启发,提出一种新型的智能优化算法——爆炸搜索算法(ESA)。该算法引入邻域搜索的思想,包含3个重要算子：爆炸搜索算子,迁移算子,变异算子,具有较大的局部-全局搜索能力,且收敛速度快、稳定性好。对benchmark函数集进行仿真并与CPSO等算法进行比较,实验结果证实了ESA的高效性。     

Efficient Reorganization of Binary Search Trees

We consider the problem of maintaining a binary search tree ({bst}) that minimizes the average access cost needed to satisfy randomly generated requests. We analyze scenarios in which the accesses are generated according to a vector of fixed probabilities which is unknown . Our approach is statistical. We devise policies for modifying the tree structure dynamically, using rotations of accessed records. The aim is to produce good approximations of the optimal structure of the tree, while keeping the number of rotations as small as possible. The heuristics that we propose achieve a close approximation to the optimal BST, with lower organization costs than any previously studied. We introduce the MOVE_ONCE rule. The average access cost to the tree under this rule is shown to equal the value achieved by the common rule Move to the Root (MTR). The advantage of MOVE_ONCE over MTR and similar rules is that it relocates each of the items in the tree at most once. We show that the total expected cost of modifying the tree by the MOVE_ONCE rule is bounded from above by 2(n+1)H _n -4n rotations (in a tree with n records), where H _n is the n th harmonic number. Extensive experiments show that this value is an overestimate, and in fact the number of rotations is linear for all the access probability vectors we tested. An approximate analysis is shown to match the experimental results, producing the expected number n((π ² /3)-2) - 2\ln n+0.1354 . Next we combine the MOVE_ONCE rule with reference counters, one per record, that provide estimates of the reference probabilities. We call the resulting reorganization rule MOUCS. We show that, for any δ , α >0 and sufficiently large n , it achieves a cost that approaches the optimum up to an absolute difference of δ with probability higher than 1- α , within a number of accesses that is proportional to n (\lg n) ² /(αδ ² ) . Received March 10, 2001; revised March 26, 2001.     

求解工件车间调度问题的一种新的邻域搜索算法

该文提出了一种新的求解工件车间调度(job shop scheduling)问题的邻域搜索算法．问题的目标是：在满足约束条件的前提下使得调度的makespan尽可能地小．定义了一种新的优先分配规则以生成初始解;定义了一种新的邻域结构;将邻域搜索跟单机调度结合在一起;提出了跳坑策略以跳出局部最优解并且将搜索引向有希望的方向．计算了当前国际文献中的一组共58个benchmark问题实例,算法的优度高于当前国外学者提出的两种著名的先进算法．其中对18个10工件10机器的实例,包括最著名的难解实例ft10,在可接受的时间内都找到了最优解．这些实例是当前文献中报导的所有规模为10工件10机器的实例．     

禁忌搜索算法用于解决网络路由问题

Routing problem is a very import problem in the network design.However,with the increasing of the number of vertices,the convergence speed of the conventional method(such as the Dijkstra algorithm)becomes slow.In some services,the accurate shortest path isn't requested.This paper presents a new algorithm for solving this problem based on the tabu search technique.The tabu search algorithm can get the satisfied path with the changing of the iteration times,the tabu period and neighborhood size.Simulation results demonstrate that the proposed method is very efficient for computing the shorted path,especially when the scale of the network is large.     

Clustering Search for the Berth Allocation Problem

This work presents a new approach to the Berth Allocation Problem (BAP) for ships in ports. Due to the increasing demand for ships carrying containers, the BAP can be considered as a major optimization problem in marine terminals. In this paper, the BAP is considered as dynamic and modeled in discrete case and we propose a new alternative to solve it. The proposed alternative is based on applying the Clustering Search (CS) method using the Simulated Annealing (SA) for solutions generation. The CS is an iterative method which divides the search space in clusters and it is composed of a metaheuristic for solutions generation, a grouping process and a local search heuristic. The computational results are compared against recent methods found in the literature.     

Self Controlling Tabu Search algorithm for the Quadratic Assignment Problem

This paper addresses the application of the principles of feedback and self-controlling software to the tabu search algorithm. We introduce two new reaction strategies for the tabu search algorithm. The first strategy treats the tabu search algorithm as a target system to be controlled and uses a control-theoretic approach to adjust the algorithm parameters that affect search intensification. The second strategy is a flexible diversification strategy which can adjust the algorithm’s parameters based on the search history. These two strategies, combined with tabu search, form the Self Controlling Tabu Search (SC-Tabu) algorithm. The algorithm is implemented and tested on the Quadratic Assignment Problem (QAP). The results show that the self-controlling features of the algorithm make it possible to achieve good performance on different types of QAP instances.     

改进布谷鸟搜索算法求解批量流水线调度问题

针对以最大完工时间为目标的批量流水线调度问题,提出一种改进的布谷鸟搜索算法．该算法采用排序规则的编码方式,将连续个体值的布谷鸟搜索算法直接应用于离散的调度问题．其次,在布谷鸟搜索算法的基础上,一个简单而有效的局部搜索用于批量流水线调度问题的探索．仿真实验表明所提出算法的可行性和有效性．