自由曲面高斯图中最小闭域计算     

欧新良  陈松乔  方逵 《湘南学院学报》2006,27(5):21-23

基于拓扑不变性和抛物线端点处可求切线,设计了一个高斯图闭域网中最小闭域计算算法,利用多边形逼近抛物线段的特点,改进多边形包含测试算法来实现闭域包含测试,可将高斯图闭域网分解成最小闭域集———单类型区域.最后给出了一个计算实例.  相似文献   

An investigation of Taiwan University students' perceptions of online academic help seeking, and their web-based learning self-efficacy     

Kun-Hung Cheng  Chin-Chung Tsai 《The Internet and Higher Education》2011,14(3):150-157

This study was conducted to investigate Taiwan University students' perceptions (including experience, confidence and preference) of online academic help seeking (OAHS) and students' level of web-based learning self-efficacy (WLSE). Two instruments, OAHS questionnaire, consisting of information searching, formal and informal query scales, and WLSE questionnaire, including general and functional scales, were then validated through collecting the responses from 300 university students. Results indicate reciprocal relations between experience, confidence and preference in students' online academic help seeking behaviors. Students' academic help seeking behaviors were related to their general self-efficacy in a web-based course setting. Students' functional WLSE was related to their perceptions of information searching for OAHS. Findings of this study also imply that students' experience of seeking help from informal online channels is prominent when they participate in a web-based course.  相似文献   

谈培养学生创新思维能力的思路和途径     

潘吉明 《湖州师范学院学报》2001,(Z1)

从数学教学中重视知识发生过程教学；引导学生从观察实际生活中建立数学模型；解题中构建求异探索；鼓励学生大胆质疑；营造良好的学习环境五个方面，阐明了培养学生创新思维能力的思路和途径．  相似文献   

Improving the learning of Boolean queries by means of a multiobjective IQBE evolutionary algorithm     

O. Cordón  E. Herrera-Viedma  M. Luque 《Information processing & management》2006

The Inductive Query By Example (IQBE) paradigm allows a system to automatically derive queries for a specific Information Retrieval System (IRS). Classic IRSs based on this paradigm [Smith, M., & Smith, M. (1997). The use of genetic programming to build Boolean queries for text retrieval through relevance feedback. Journal of Information Science, 23(6), 423–431] generate a single solution (Boolean query) in each run, that with the best fitness value, which is usually based on a weighted combination of the basic performance criteria, precision and recall.  相似文献   

Analyzing imbalance among homogeneous index servers in a web search system     

C.S. Badue  R. Baeza-Yates  B. Ribeiro-Neto  A. Ziviani  N. Ziviani 《Information processing & management》2007

The performance of parallel query processing in a cluster of index servers is crucial for modern web search systems. In such a scenario, the response time basically depends on the execution time of the slowest server to generate a partial ranked answer. Previous approaches investigate performance issues in this context using simulation, analytical modeling, experimentation, or a combination of them. Nevertheless, these approaches simply assume balanced execution times among homogeneous servers (by uniformly distributing the document collection among them, for instance)—a scenario that we did not observe in our experimentation. On the contrary, we found that even with a balanced distribution of the document collection among index servers, correlations between the frequency of a term in the query log and the size of its corresponding inverted list lead to imbalances in query execution times at these same servers, because these correlations affect disk caching behavior. Further, the relative sizes of the main memory at each server (with regard to disk space usage) and the number of servers participating in the parallel query processing also affect imbalance of local query execution times. These are relevant findings that have not been reported before and that, we understand, are of interest to the research community.  相似文献   

基于SuperMap的地形图图幅查询系统设计与实现     

戚国强 《嘉应学院学报》2011,29(8):82-86

基于VB和SuperMap Objects 2008平台,设计实现地形图图幅查询系统.该系统可在1954年北京坐标系或1980年西安坐标系下,实现任意单点或批量坐标解算任意国家基本比例尺地形图新、旧图幅编号,并能根据任意新、旧图幅编号计算四角图廓坐标,并可视化输出.  相似文献   

独立建设“创新实验室”的必要性质疑   总被引：2，自引：1，他引：1  

田爱平  姜爱民  张慧 《实验室研究与探索》2011,30(11)

高等院校所提倡的创新实验教学主要应定位在特定知识领域基础知识体系上的突破,而不应一味的追求创新.近年来国内掀起一股独立建设“创新实验室”的热潮,针对此“创新实验室”蓬勃兴起的现象,指出创新性是实验室的应有本质特征,传统实验室创新教育功能的不足是应有功能的缺失.对独立建设“创新实验室”的必要性提出质疑,主张传统实验室创新教育功能的本性“回归”.认为“传统”与“创新”不但不矛盾,而且是统一的,两者的组合才是一个真正实验室所应扮演的完整“角色”.补充传统实验室缺失的创新教育功能是我国高等院校实验室建设的一条可选道路.  相似文献   

基于社区多角色的结构化P2P网络查询技术研究     

李冉  余镇危 《荆门职业技术学院学报》2011,26(2):11-16

针对一种新型的基于社区多角色的结构化P2P网络模型特点,提出了一种新的查询算法,即迭代扩展查询算法。该算法利用反馈机制,将已经返回的结果统计信息反馈到前端查询Q,指导查询Q向外路由的策略。将该算法与Chord网络查询算法进行了分析比较,使用P2Psim进行模拟验证。仿真结果表明,该网络模型性能稳定,资源查询速度快,通信量小,结果优良。  相似文献   

The Co-Effects of Query Structure and Expansion on Retrieval Performance in Probabilistic Text Retrieval     

Jaana Kekäläinen  Kalervo Järvelin 《Information Retrieval》2000,1(4):329-344

The effects of query structures and query expansion (QE) on retrieval performance were tested with a best match retrieval system (InQuery¹). Query structure means the use of operators to express the relations between search keys. Six different structures were tested, representing strong structures (e.g., queries with facets or concepts identified) and weak structures (no concepts identified, a query is a bag of search keys). QE was based on concepts, which were first selected from a searching thesaurus, and then expanded by semantic relationships given in the thesaurus. The expansion levels were (a) no expansion, (b) a synonym expansion, (c) a narrower concept expansion, (d) an associative concept expansion, and (e) a cumulative expansion of all other expansions. With weak structures and Boolean structured queries, QE was not very effective. The best performance was achieved with a combination of a facet structure, where search keys within a facet were treated as instances of one search key (the SYN operator), and the largest expansion.  相似文献   

基于边缘逆理论的辨识系统并行查询扩展算法     

姜攀 《科技通报》2015,(2):76-78

多源数据辨识系统广泛应用在机载数据辨识控制、大型机械设备故障诊断和云存储系统数据库集成等领域。对多源数据的辨识系统并行查询和数据调度中,因数据的静态非线性测量过程影响了查询效益,需要对辨识系统并行查询链路进行扩展。提出一种基于振幅调节Fourier变换边缘逆理论的辨识系统并行查询扩展算法。进行多源数据辨识系统基本构造和模型设计,提取查询特征信息,采用RBF神经网络系统进行多源数据输入自适应学习,构建神经网络辨识系统的边缘逆向量,采用边缘逆理论进行振幅调节Fourier变换实现多源查询数据的状态重组,实现查询链路扩展设计改进。仿真结果表明,该算法提高了辨识系统的查询通道的链路相位,多源数据调度的时间成本及空间成本大幅降低,加速比提高,算法将在系统状态识别、机械故障智能诊断等领域具有较高的应用价值。  相似文献