应用过定位实现零件的高精度加工     

刘越 《九江职业技术学院学报》2003,(4):11-13

过定位属违反工件定位原理的一种定位方式，使用不当或破坏工件的正确定位，会影响加工精度或造成干涉使工件无法安装；如若处理得好，过定位不仅能提高工件的定位精度，还能提高工件的安装刚度。本从工程实际出发，介绍一种过定位的具体应用。  相似文献   

求∫e~(αx)[P_l(x)cosβx+P_n(x)sinβx]dx型不定积分的几种方法     

王捷 《雁北师范学院学报》2002,(2)

对于形如∫eαx[P1 (x) cosβx +Pn(x) sinβx]dx的不定积分 ,求解过程非常繁锁 .考虑到被积函数及其原函数的特点 ,这里分别讨论几种非常规性的求解方法 ,即比较系数法、分部积分的列表法和复数法 ,以开阔学生的思路 ,培养学生综合应用所学知识的能力 .  相似文献   

A developmental review of response time data that support a cognitive components model of reading   总被引：2，自引：0，他引：2  

Greene  Barbara A.  Royer  James M. 《Educational Psychology Review》1994,6(2):141-172

The present article provides a review of numerous studies that measured response times for cognitive tasks related to six components of the reading process. The component processes were single-letter recognition, multi-letter unit identification, word and pseudoword identification, semantic access/concept activation, phrase and sentence comprehension, and text comprehension. The response time data are presented in tables and summarized in the text. The data provide support for a componential view of reading.  相似文献   

Effects of different training conditions in the acquisition of a handwriting task     

Stanley J. Portier  Henk Hylkema  Ruud G. J. Meulenbroek  Gerard P. Van Galen 《Reading and writing》1991,3(1):43-62

  相似文献   

Digital Signal Processing Based Real Time Vehicular Detection System   总被引：4，自引：1，他引：4  

杨兆选 林涛李香萍  刘春义高健 《天津大学学报(英文版)》2005,11(2):119-124

Traffic monitoring is of major importance for enforcing traffic management policies. To accomplish this task, the detection of vehicle can be achieved by exploiting image analysis techniques. In this paper, a solution is presented to obtain various traffic parameters through vehicular video detection system( VVDS). VVDS exploits the algorithm based on virtual loops to detect moving vehicle in real time. This algorithm uses the background differencing method, and vehicles can be detected through luminance difference of pixels between background image and current image. Furthermore a novel technology named as spatio-temporal image sequences analysis is applied to background differencing to improve detection accuracy. Then a hardware implementation of a digital signal processing (DSP) based board is described in detail and the board can simultaneously process fourchannel video from different cameras. The benefit of usage of DSP is that images of a roadway can be processed at frame rate due to DSP‘s high performance. In the end, VVDS is tested on realworld scenes and experiment results show that the system is both fast and robust to the surveillance of transportation.  相似文献   

车牌识别技术中字符切割新算法     

李元金  高维春  王精明 《深圳信息职业技术学院学报》2007,5(1):32-34

先对切割下来的车牌进行水平扫描,确定车牌上文字在水平上的大致范围;然后再对确定水平范围后的车牌图像进行竖直扫描确定车牌上每个字符的大致宽度;最后把它们切割下来并进行归一化处理,为下一步车牌特征提取打下了基础。实验结果的数据表明该方法对车牌上字符的切割具有很好的效果。  相似文献   

两个加工时间恶化的半线性平行机排序问题的启发式MBLS 算法     

程明宝  孙世杰 《上海大学学报(英文版)》2007,11(5):451-456

The combination of online or semi-online with deterioration jobs has never been researched in scheduling problems. In this paper, two semi-online parallel machine scheduling problems with linear deterioration processing time are considered. In the first problem, it is assumed that the deterioration rates of jobs are known in an interval, that is, bj ∈[0, α], where 0 〈α≤ 1 and bj denotes the linear deterioration rate. In the second problem, it is assumed that the largest deterioration rate of jobs is known in advance, that is, b = max1≤j≤n {bj }. For each of the two problems, a heuristic MBLS algorithm is worked out and its worst-case ratio is analyzed. At the same time, the worst-case ratio of the list （LS） algorithm is investigated and it is proved that all the ratios are tight.  相似文献   

浅析工程图学信息化教学改革     

张宗波  王珉  伊鹏  牛文杰  刘广斗  王伟  张芬娜 《教育教学论坛》2019,(9):116-117

随着高等教育信息化改革的不断深入,工程图学作为工科重要的基础课程其信息化改革已成为必然趋势。本文结合工程图学课程的特点与信息化教育改革的发展历程,分析了目前工程图学信息化教学过程中存在的不足之处,并提出了科学合理发展工程图学信息化教学的几点认识。  相似文献   

Time allocation scheme in IEEE 802.15.3 TDMA mechanism   总被引：1，自引：0，他引：1  

LIU Xin  DAI Qiong-hai  WU Qiu-feng 《浙江大学学报(A卷英文版)》2006,7(Z1)

In network with a shared channel in TDMA mechanism, it is a core issue to effectively allocate channel time to provide service guarantees for flows with QoS requirements. This paper proposes a simple and efficient time allocation scheme called MES-ESRPT (MCTA at the End of Superframe-Enhanced Shortest Remaining Processing Time) for delay-sensitive VBR traffic in accordance with IEEE 802.15.3 standard. In this algorithm, PNC (piconet coordinator) allocates one MCTA (Management Channel Time Allocation) for each stream which is the process of communication at the end of superframe. During the MCTA period, each transmitter should report current fragments number of the first MSDU (MAC Service Data Unit) and the fragments number of the remainder MSDUs to PNC. In the next superframe, PNC firstly allocates part CTAs (Channel Time Allocation) for each stream based on the remainder fragments number of the first MSDU by SRPT rule, then allocates remainder CTAs for each stream based on all fragments number of remainder MSDUs by the same SRPT rule. Simulation results showed that our proposed MES-ESRPT method achieves significantly better performance in QoS for multimedia streams compared to the existing schemes.  相似文献   

在试题库系统中利用VFP6.0生成EXCEL电子图表     

林玲 《伊犁师范学院学报》2004,(3):75-77

在WINDOWS平台的Visual FoxPro 6．0环境中，实现了读取数据库中的数据生成EXCEL电子图表，并给出了具体的程序实例及相关代码。  相似文献