共查询到19条相似文献,搜索用时 187 毫秒
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根据初始状态和终止状态是否为分明的,非确定型量子有穷自动机可分为四类,确定型量子有穷自动机可分为三类.本文详细讨论了四类非确定型量子有穷自动机之间的关系以及三类确定型量子有穷自动机之间的关系,并且利用新的构造方法,证明了初态为分明的确定型量子有穷自动机与终态为分明的确定型量子有穷自动机是等价的.这些结论为实际应用中计算模型的合理选取提供了理论依据. 相似文献
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为解决BW-RAID系统中数据冗余模式从镜像向RAID4转换时的节点间缓存数据版本识别问题,提出了一种分布式异步版本识别机制。该版本识别机制在镜像卷中的一个逻辑块被更新时,为其生成一个新版本;在冗余模式转换时,通过比较镜像节点间的版本判定某一逻辑块在两个镜像节点缓存的数据是否一致,如果数据一致将其迁移到数据存储卷,否则暂存入镜像节点各自的磁盘缓存以保证系统的冗余一致性。实验表明,该机制在系统正常、降级、故障恢复状态下均能准确、有效识别一致数据;顺序写评测中存储负载小于1%,平均带宽提升最高达25.43%;Open-mail负载重播评测中存储负载低于40%,应用重播结束时写更新数据均完成冗余模式转换,实现了提高空间利用率的目标。 相似文献
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遗传算法的改进及其在水库优化调度中的应用研究 总被引:14,自引:1,他引:13
遗传算法是通过对样本中个体的不断改进来寻找各类问题的最优解。由于标准遗传算法(SGA)存在收敛性及个体适应度求解方面的困难,在研究中,通过对SGA中遗传算子改进,特别是对选择算子的改进,提出了一种改进遗传算法(AGA),并将它应用于水库优化调度中。改变通常以水位变化序列为基础的遗传算法编码方案,通过数组存储水库库容状态,并以各库容状态对应的数组下标为基础进行遗传算法编码,通过实例,表明AGA对水库优化调度问题具有良好的适应性,同时结合数组存储理论的遗传算法编码方法简化了水库优化调度遗传算法的实现过程。 相似文献
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考虑到协议一致性测试中基于扩展有限状态自动机( EFSM)模型的测试序列生成仍然是一个尚无理想方法解决的开放性问题,提出了一种面向协议一致性测试的基于EFSM模型的测试序列生成方法.此方法将EFSM模型转换成确定化的EFSM (DEFSM)模型,并在转换过程中对EFSM模型中的条件和操作冲突进行检测并加以消除,此外,通过测试序列生成附加模块的协助,可将变量及其条件判定从DEFSM模型中分离出来,使得处理后的DEFSM模型等同于有限状态自动机(FSM)模型,从而将EFSM的描述优势和基于FSM模型的测试序列生成优势进行有效的结合.理论和实验分析结果显示了此方法的有效性. 相似文献
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二维数组使用一般有两种情况,一种是描述一个二维的事物。比如用1表示墙,用0表示通路,我们可以用二维数组来描述一个迷宫地图;用1表示有通路,0表示没有通路,我们可以用二维数组来描述几个城市之间的交通情况。还有一种是描述多个具有多项属性的事物。比如有多个学生,每个学生有语文、数学和英语三门成绩,我们就可以用二维数组来描述。对二维数组使用过程中的几个问题进行探究。 相似文献
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Waldemar Celes Glaucio H. Paulino Rodrigo Espinha 《International journal for numerical methods in engineering》2005,64(11):1529-1556
This paper presents a novel compact adjacency‐based topological data structure for finite element mesh representation. The proposed data structure is designed to support, under the same framework, both two‐ and three‐dimensional meshes, with any type of elements defined by templates of ordered nodes. When compared to other proposals, our data structure reduces the required storage space while being ‘complete’, in the sense that it preserves the ability to retrieve all topological adjacency relationships in constant time or in time proportional to the number of retrieved entities. Element and node are the only entities explicitly represented. Other topological entities, which include facet, edge, and vertex, are implicitly represented. In order to simplify accessing topological adjacency relationships, we also define and implicitly represent oriented entities, associated to the use of facets, edges, and vertices by an element. All implicit entities are represented by concrete types, being handled as values, which avoid usual problems encountered in other reduced data structures when performing operations such as entity enumeration and attribute attachment. We also extend the data structure with the use of ‘reverse indices’, which improves performance for extracting adjacency relationships while maintaining storage space within reasonable limits. The data structure effectiveness is demonstrated by two different applications: for supporting fragmentation simulation and for supporting volume rendering algorithms. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Neng-Pin Lu 《中国工程学刊》2016,39(8):936-945
The bowtie structure can illustrate not only the accessibility of the World Wide Web, but also the reachability of other directed networks. In this paper, we use the principal eigenvectors of the adjacency matrix with the unique largest eigenvalue to identify the strongly connected component of a directed network and fit the network into the bowtie structure. To ensure that the largest eigenvalue is unique, we add a little perturbation to the matrix before the eigen analysis. After the revelation of the bowtie structure centered on the strongly connected component with the largest unique eigenvalue, a directed network may have other bowtie structures centered on strongly connected components with smaller eigenvalues. To reveal other bowtie structures, we collapse the perturbed matrix by aggregating nodes of the strongly connected component with the largest eigenvalue into a supernode. Hence, the principal eigenvectors of the perturbed and collapsed matrix can be used to reveal the bowtie structure centered on the strongly connected component with the second largest eigenvalue. Furthermore, repeating the process of collapsing a strongly connected component and finding principal eigenvectors of the perturbed and collapsed matrix, we can reveal all the bowtie structures of a directed network. 相似文献
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座舱显示器周边各键尺寸、方位和间隔的工效学实验研究 总被引:3,自引:3,他引:0
飞机座舱显现器周边各键是重要控制器,它的尺寸、方位、排列方向、键间隔是影响工效的重要因素。该研究用两个实验探讨了周边各键的尺寸、方位、间隔对反应时的影响。结果表明:键尺寸、方位、排列方向对反应时有影响,键的间隔对反应时没有影响 相似文献
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双输入整形器抑制两轴转动太阳翼调姿后的残余振动 总被引:1,自引:0,他引:1
在非惯性系下建立太阳电池翼的运动方程,完成双输入整形器的理论推导,解决两轴转动太阳电池翼调姿后的残余振动问题。双输入整形器根据太阳电池翼的结构固有振动特性,包括固有频率、阻尼比、质量阵和模态向量,针对每个转角输入设计基于连续传递函数的双输入整形器,用于抑制两轴转动太阳电池翼调姿后的残余振动。通过太阳电池翼弯曲-扭转两轴转动有限元模型动力学仿真,验证整形后的转角输入函数驱动太阳电池翼调姿能有效抑制残余振动,且在电池翼结构参数有所震荡的情况下具有较好的鲁棒性。 相似文献
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储罐探伤爬壁机器人全遍历路径规划方法 总被引:1,自引:0,他引:1
储罐探伤爬壁机器人全遍历路径规划要求机器人高效遍历储罐外壁全部无障碍物区域。结合邻接矩阵、路径选择函数,提出一种单元分解算法并应用于爬壁机器人路径规划中。首先,将爬壁机器人的工作环境简化为二维平面,并通过分析漏检面积确定机器人遍历基本路径;接着,建立栅格环境,对每个栅格赋予xi值以表示其栅格状态;其次,采用矩形分解法将工作环境划分为若干子区域,通过图的深度优先搜索算法和邻接矩阵确定各子区域的衔接顺序;最后,在子区域的遍历和切换过程中,引入方向函数yi来判断爬壁机器人是否陷入死区,结合xi值提出路径选择函数fi以引导爬壁机器人快速逃离死区。在虚拟环境中进行了仿真实验,仿真结果表明,该方法不仅能引导爬壁机器人以高覆盖率和低重复率遍历工作区域,而且能快速地逃离死区。全遍历路径规划的实现拓展了爬壁机器人在检测储罐罐壁中的应用。 相似文献
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J. F. Wu M. S. Shephard G. J. Dvorak Y. A. Bahei-El-Din 《Composites Science and Technology》1989,35(4):347-366
A finite element based procedure is presented which accounts for micromechanical nonlinear behavior of the matrix material in continuous fiber reinforced composites. The micromechanical model is a periodic hexagonal array of elastic fibers embedded in an elastic-plastic matrix material. This model is used to calculate the overall instantaneous material matrix at material points of a macromechanical finite element model of the structure being analyzed. The procedure is applied to a number of metal matrix composite systems subjected to thermomechanical loads. 相似文献
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An effective facility layout implies that departments with high flow are laid adjacent. However, in the case of a very narrow boundary length between the neighbouring departments, the adjacency would actually be useless. In traditional layout design methods, a score is generally assigned independent of the department’s boundary length. This may result in a layout design with a restricted material flow. This article proposes a new concept of adjacency in which the department pairs are laid adjacent with a wider path. To apply this concept, a shop with unequal rectangular departments is contemplated and a mathematical programming model with the objective of maximizing the sum of the adjacency degrees is proposed. A computational experiment is conducted to demonstrate the efficiency of the layout design. It is demonstrated that the new concept provides a more efficient and a more realistic layout design. 相似文献