共查询到20条相似文献，搜索用时 312 毫秒
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王苏苏 《宁波职业技术学院学报》2014,(6):76-81
传统的方法一般通过统计分析语句的覆盖信息来进行错误定位。然而,在并发程序执行时,由于多个线程的交替运行,使得传统的方法进行错误定位的效率不高。提出了基于动态并发程序切片的错误定位技术（Dynamic Concurrent Slicing-based Fault Localization,DCS-FL）,以在对传统的串行错误进行定位的同时,较有效地识别出并发错误。这种技术根据失效测试构建动态并发切片缩小错误搜索域,然后在此基础之上通过度量错误搜索域中元素可疑度来进行错误定位。最后,通过实例数据验证了该方法的有效性。 相似文献
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为解决含过程程序的单子切片问题,提出基于回填待定标号的两阶段单子切片算法．算法第1阶段用给定标号初始化子过程的形参切片表,并通过分析调用语句捕获被调者对调用者的影响．算法第2阶段主要是通过回填切片表中相应的待定标号来捕获施调者对被调者的影响．待定标号的引入使得所提切片算法可捕获类似基于系统依赖图（SDG）切片算法中的概要信息,且也可避免上下文调用问题．借助于切片单子转换器,所提单子切片算法将具有较高的模块性和适应性,且其复杂度不劣于基于SDG的切片算法． 相似文献
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赵海廷 《武汉工程职业技术学院学报》2005,17(1):36-39
变量的生存期和作用域是程序中引用该变量的依据，本文主要探讨Java语言中公有变量、静态变量、类的数据成员、方法的参数、异常处理参数和局部变量的作用域问题，给出了静态变量、类的数据成员变量和异常处理参数作用域的程序举例，说明其具体的应用方法。 相似文献
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本文采用形式语义研究方法,结合实例重点探讨了高级语言程序设计中局部变量在语句块中的作用域问题,从而帮助高级语言程序学习者从另一个角度分析局部变量的作用域。 相似文献
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K-means算法在聚类过程中随机选取k个初始聚类中心,容易造成聚类结果不稳定。针对该问题,提出PCA-TDKM算法：使用主成分分析法对数据对象集合的属性进行降维,提取出主属性,去掉无关属性,从而加速聚类过程;基于最小生成树算法及树的剪枝方法将数据对象划分为k个初始聚类簇,然后进行剪枝生成k棵子树,计算每棵子树中所有数据对象的均值,作为初始聚类中心;利用基于密度与最大最小距离的算法思想进行聚类。将PCA-TDKM算法与K-means、KNE-KM、QMC KM、CFSFDP-KM在UCI数据集上进行聚类比较,结果表明该算法聚类结果稳定、聚类准确率高。 相似文献
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人体切片数据的三维重建系统设计 总被引：2，自引：0，他引：2
阐述了利用人体切片数据，从二维图像中提取三维信息，并采用OpenGL开发工具进行三维重建的方法。根据不同点云绘制方法与计算消耗时间的关系，重点提出如何结合点云绘制与网格绘制，有效、快速的实现了人体切片数据的三维重建。 相似文献
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随着生命科学研究的深入发展,对大通量、大面积、大视野样品的分析越来越需要。玻片扫描是利用全自动显微镜扫描系统,结合虚拟切片软件,把传统切片进行扫描、无缝拼接,生成一整张全视野的数字切片。为促进虚拟切片扫描类大型仪器给教学和科研工作提供更好的共享服务,通过介绍OLYMPUS VS120虚拟数字切片扫描系统的硬件配置、成像特点和软件功能,结合具体使用实例探讨该仪器在组织病理学、神经生物学、发育生物学等研究领域尤其大视野拼图的重要应用。总结仪器使用过程中遇到的问题,分析造成的原因,提出解决方案,为数字切片扫描系统的共享使用提供了借鉴和参考。 相似文献
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吴绍根 《北京工业职业技术学院学报》2015,14(3):20-25
针对近年来基于网格和密度的数据聚类算法均需要先验知识确定聚类相关参数的问题,提出了基于动态网格和密度邻接的数据聚类算法。该算法首先分析数据集的特征,确定网格单元的初始值,通过定义全局距离度量函数,对网格单元进行2-1动态递减迭代,最后得到全局最优聚类。实验结果证明:使用该算法对数据进行聚类,能够获得直觉上的最优聚类结果。将该算法应用到对GPS信息聚类中,也得到较为理想的效果。 相似文献
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用在设计阶段可以收集到的3个规模度量分析类规模对面向对象度量与易维护性之间关联关系的混和效果.为得到尽可能通用的结论,在127个C＋＋系统和113个Java系统上分析类规模的混和效果.首先,对每个面向对象度量,在单个系统上计算代表由类规模造成的关联扭曲的间接效果和它的方差.然后,利用统计的元分析方法计算这些系统上的平均间接效果并判断它是否显著地区别于零.实验结果表明,不论使用哪个类规模度量进行分析,类规模对面向对象度量与易维护性之间关联关系的混和效果通常是存在的.因此,验证面向对象度量与易维护性之间关系的实验研究应将类规模视为一个混和变量. 相似文献
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Robert Henson Jonathan Templin Jeffrey Douglas 《Journal of Educational Measurement》2007,44(4):361-376
Consider test data, a specified set of dichotomous skills measured by the test, and an IRT cognitive diagnosis model (ICDM). Statistical estimation of the data set using the ICDM can provide examinee estimates of mastery for these skills, referred to generally as attributes. With such detailed information about each examinee, future instruction can be tailored specifically for each student, often referred to as formative assessment. However, use of such cognitive diagnosis models to estimate skills in classrooms can require computationally intensive and complicated statistical estimation algorithms, which can diminish the breadth of applications of attribute level diagnosis. We explore the use of sum-scores (each attribute measured by a sum-score) combined with estimated model-based sum-score mastery/nonmastery cutoffs as an easy-to-use and intuitive method to estimate attribute mastery in classrooms and other settings where simple skills diagnostic approaches are desirable. Using a simulation study of skills diagnosis test settings and assuming a test consisting of a model-based calibrated set of items, correct classification rates (CCRs) are compared among four model-based approaches for estimating attribute mastery, namely using full model-based estimation and three different methods of computing sum-scores (simple sum-scores, complex sum-scores, and weighted complex sum-scores) combined with model-based mastery sum-score cutoffs. In summary, the results suggest that model-based sum-scores and mastery cutoffs can be used to estimate examinee attribute mastery with only moderate reductions in CCRs in comparison with the full model-based estimation approach. Certain topics are mentioned that are currently being investigated, especially applications in classroom and textbook settings. 相似文献
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Bei LI Yao WANG 《Journal of Zhejiang University. Science. B》2014,15(12):1064-1071
研究目的：创新要点：研究方法：重要结论：观察人类上颌中切牙拔除后牙槽骨外形改建的规律。锥形束计算机断层摄影（CBCT）在口腔硬组织测量方面具有可靠性,在不同时期拍摄的影像中测量具有可重复性。本研究充分利用这一影像学工具观察人类上颌中切牙拔除后牙槽骨改建的规律。选择40名患者上颌中切牙拔牙前和拔牙后三个月时拍摄的两份CBCT影像资料。在第一次CBCT中,选取中切牙拔牙窝深、中、浅三个水平断层进行矢状断层重建,分别记录矢状断层起点到拟拔除中切牙（实验牙T）牙髓中心移动的层数,并测量实验牙T处牙槽骨宽度,在中切牙拔牙窝中层测量腭平面相关垂直距离。在第二次CBCT的三个水平断层上,依据第一次记录的移动层数定位实验牙T,并在定位处测量牙槽骨宽度。在中切牙拔牙窝中层上转移第一次CBCT记录的腭平面相关距离,并测量唇腭侧牙槽嵴顶沿原牙根外形垂直吸收的距离。上颌中切牙拔除后三个月,在拔牙窝的不同深度,唇侧的牙槽骨均有不同程度的水平骨吸收,越接近牙槽嵴项处牙槽骨吸收越明显。唇腭侧牙槽嵴顶均有明显的垂直骨吸收,唇侧牙槽嵴项的垂直骨吸收比腭侧明显。 相似文献
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研究目的：探讨同一患者不同时期所拍的锥形束计算机断层摄影（CBCT）是否因每次拍摄时投照角度不可能完全一致而影响数据测量的准确性。创新要点：提出了一种人类后牙拔除后观察牙槽突外形变化的准确、无创、科学的定位方法。研究方法：选择首都医科大学附属北京口腔医院种植中心60名患者两份于上颌后牙种植前后拍摄的CBCT影像资料。以磨牙根分叉区三个牙根开始分开处（图像上显示为三根恰好融合的点）为基准点定位两次CBCT的起始水平断层。在第一次CBCT的起始水平断层上,连线牙列远端磨牙参照点即矢状断层起点与近端双尖牙的髓室中心进行矢状断层重建。若实验牙为第一磨牙,找到通过其腭根髓室中心的矢状断层;若实验牙为第二双尖牙,找到通过其髓室中心的矢状断层。记录由矢状断层起点到实验牙移动的层数N,在水平断层上测量实验牙牙槽骨宽度,在实验牙髓室中心的矢状断层上测量牙全长。在第二次CBCT中依据第一次记录的移动层数N定位矢状断层,在定位后的矢状断层上测量实验牙全长,在水平断层的相应定位处测量牙槽骨宽度。重要结论：利用本研究提出的定位方法可以精准定位同一患者不同CBCT影像资料中的同一断层,从而实现拔牙位点动态连续观察。 相似文献
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利用单片机技术,把所要显示的内容以及DMD协议通过编程器写入单片机的存储器中.通过电脑通信RS-232,并按照DMD协议发送命令,调用单片机内部存储器的内容,再由单片机把数据传送到LED点阵上.显示屏上就能显示出通过电脑所调用的内容.本产品具有使用方便,性能稳定的特点. 相似文献
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Kathleen M. Sheehan 《Educational Measurement》2013,32(4):28-37
Many proposed cohesion metrics focus on the number and types of explicit cohesive ties detected within a text without also considering differences in the ease or difficulty of required referential and connective inferences. A new cohesion measure structured to address this limitation is proposed. Empirical analyses confirm that this new measure performs similarly to existing measures when applied to the simpler problem of detecting lower and higher cohesion versions of the same text, yet is significantly more effective than existing measures when applied to the more complex problem of distinguishing different texts rated by human experts as requiring lower or higher levels of reading comprehension skill. Implications of these findings relative to the goal of helping teachers and other educators select texts for use in instruction and assessment are discussed. 相似文献
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Culturally responsive assessments have been proposed as potential tools to ensure equity and fairness for examinees from all backgrounds including those from traditionally underserved or minoritized groups. However, these assessments are relatively new and, with few exceptions, are yet to be implemented in large scale. Consequently, there is a lack of guidance on how one can compute comparable scores on various versions of these assessments. In this paper, the multigroup multidimensional Rasch model is repurposed for modeling data originating from various versions of a culturally responsive assessment and for analyzing such data to compute comparable scores. Two simulation studies are performed to evaluate the performance of the model for data simulated from hypothetical culturally responsive assessments and to find the conditions under which the computed scores are accurate. Recommendations are made for measurement practitioners interested in culturally responsive assessments. 相似文献
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The Transition from Comparison of Finite to the Comparison of Infinite Sets: Teaching Prospective Teachers 总被引：1，自引：0，他引：1
Pessia Tsamir 《Educational Studies in Mathematics》1999,38(1-3):209-234
Research in mathematics education indicates that in the transition from given systems to wider ones prospective teachers tend to attribute all the properties that hold for the former also to the latter. In particular, it has been found that, in the context of Cantorian Set Theory, prospective teachers have been found to erroneously attribute properties of finite sets to infinite ones — using different methods to compare the number of elements in infinite sets. These methods which are acceptable for finite sets, lead to contradictions with infinite ones. This paper describes a course in Cantorian Set Theory that relates to prospective secondary mathematics teachers' tendencies to overgeneralize from finite to infinite sets. The findings clearly indicate that when comparing the number of elements in infinite sets the prospective teachers who took the course were more successful and were also more consistent in their use of a single method than those who studied the traditional, formally-based Cantorian Set Theory course.This revised version was published online in September 2005 with corrections to the Cover Date. 相似文献
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利用VTK可视化工具包在Visual Studio2008平台上实现了医学序列图像三维的可视化．在对三维数据的预处理和优化基础上,在MFC实现的可交互界面上,用Marching Cubes（立方体移动）算法和Ray—casting（光线投射）算法对DICOM等格式的切片进行三维重建． 相似文献