魏学业
个性化签名
- 姓名:魏学业
- 目前身份:
- 担任导师情况:
- 学位:
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学术头衔:
博士生导师
- 职称:-
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学科领域:
自动化仪器仪表与装置
- 研究兴趣:
1981-1985:天津大学电子工程系本科 1985-1988:天津大学电子工程系硕士 1991-1994:北京理工大学光电工程系博士 1994-1997:北京交通大学博士后 1997至今:北京交通大学教师
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主页访问
1308
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0
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成果阅读
535
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成果数
8
【期刊论文】LBP texture analysis Based on the Local Adaptive Niblack Algorithm
魏学业, Yu Wang, Xueye Wei, Shuo Xiao
,-0001,():
-1年11月30日
Local Binary Pattern (LBP) proposed by Ojala T is a typical texture analysis algorithm. It is widely used in the texture classification domain and etc. In this paper, we consider the local pixels’ effects among them efficiently when the LBP algorithm is used. In our proposed LBP algorithm, the central pixel in the local region was added into the procedure to calculate the local threshold using the Niblack algorithm. The histogram equalization is always used to actualize the illumination invariability in LBP algorithm. But the histogram equalization can not avoid the variety of local grayscale caused by the illumination. In order to avoid this weakness, a kind of illumination factor is brought into the Niblack algorithm. The values of the illumination factor can be got adaptively with the changes of illumination. By using the improved Niblack algorithm, the local threshold can be calculated adaptively. The proposed LBP algorithm in this paper can get more texture information and it has illumination adaptability.
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250下载
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【期刊论文】One-class classifier based on SBT for analog circuit fault diagnosis
魏学业, Zhang Yi *, Wei Xueye, Jiang Haifeng
Measurement 41(2008)371-380,-0001,():
-1年11月30日
This paper presents an analog circuit fault diagnosis framework, called OCB-SBT (one-class classifier based SBT). In OCB-SBT, one-class classifiers as many as predefined fault classes are constructed from their corresponding fault simulation samples. And they serve the role of fault dictionary and classifier. This approach is simple for Go/NoGo testing because it requires only no-fault circuit simulation samples to provide the result. It will also provide "unknown fault" result if the testing object lies outside the boundary of training data, and bring "or" combined result when the testing sample belongs to the overlapped area among different fault classes. Fault diagnosis example shows that the proposed method is robust and reliable to the effects due to not only component tolerances and nonlinearity but also poorly defined fault classes and low testability.
Analog circuits, Fault classes, Fault diagnosis, One-class classifiers, SBT (, simulation before test),
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71浏览
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102下载
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【期刊论文】Variable Frequency Current-source Inverter for Grid-connected PV System
魏学业, Rongrong Yu, Xueye Wei, Xiaojin Wu
,-0001,():
-1年11月30日
A current-soure inverter with variable frequency is proposed for the grid-connected photovoltaic generation system in order to improve power quality, reduce current harmonics and decrease the frequency of switches. Besides applying energy to grid in the form of alternative current output using full-bridge switches, this topological structure can also complete maximum power point tracking by changing the duty ratio. The variable frequency current-source switch is controlled by PWM algorithm, and it is proved by computer simulation.
Variable frequency, Current-source inverter, PWM, Computer simulation
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84浏览
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1003下载
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【期刊论文】Spacial localization in wireless sensor networks based on beacon selection
魏学业, Shuo Xiao, Xueye Wei, Yu Wang
,-0001,():
-1年11月30日
The localization algorithm in wireless sensor network is always a hot spot. Information collected by the sensors is meaningless without the position of the sensors. Now, paying little attention to 3-D space, most of the algorithms are for 2-D space. In this paper we introduce a novel algorithm for 3-D space called OBS (Optimal Beacon Selection) algorithm. In this algorithm we launched the concept of position error parameter, with consideration of communication range and position accuracy of beacon. The experiment results show that this method can minimize the accumulation error and improve the location precision.
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57浏览
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172下载
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引用
魏学业, 乔志伟, 韩焱
电子测量与仪器学报,2010,24(3):263~266,-0001,():
-1年11月30日
为了加速实现长序列的线性卷积,提出了用快速哈达玛变换(FHT)实现线性卷积的快速算法。分析了哈达玛变换的特点和快速算法的时间复杂度,设计了用FHT计算线性卷积的矩阵表达式,并推导出了哈达玛域滤波器的增益矩阵的求解公式,分析了该方法的加速原理及其适用条件。理论分析和实验表明,该方法比FFT线性卷积法快了近一倍。
线性卷积, 圆周卷积, 加速, 哈达玛变换, 沃尔什变换
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94浏览
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352下载
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魏学业, 柳艳红, 吉松坡
电子学报,2008,36(7):1401~1404,-0001,():
-1年11月30日
本文提出了一种新的后非线性混合盲信号分离算法。现存算法大多需要额外的附加源信号信息,才能实现信号的分离,使盲分离变成了半盲分离。鉴于此,本文提出了一种不需要任何附加信息的全盲分离算法。首先,通过微分变换将后非线性混合模型变换成形式如同线性瞬时混合模型的形式,并论证了源信号的微分形式保留了源信号的统计特征。这样,就使非线性问题得到大大简化。其次,利用信号的相关特性建立目标函数及递推方式,用LMS算法使目标函数达到最小值,从而实现了盲信号分离的目的。最后,通过计算机仿真试验验证了本文算法的可行性和有效性。与现存算法相比,本文算法计算量小,收敛速度快,实时性好,实现了全盲分离。
盲信号分离, 后非线性, 去相关, LMS算法, 实时处理
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44浏览
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57下载
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【期刊论文】基于差分Poincar6映射的间歇混沌信号判别方法
魏学业, 谢涛, 于蓉蓉, 王钰
北京交通大学学报,2009,33(5):20~24,-0001,():
-1年11月30日
针对混沌振子微弱信号检测中间歇混沌信号难以判别的问题,利用混沌系统的参数敏感特性,提出一种差分Poincar6映射判别方法,实现强噪声干扰下输出间歇混沌信号的判别。该方法选取周期激励幅值具有微小差异的两个混沌振子的Poinear6映射进行差值运算,利用周期状态下输出信号收敛,而混沌状态下输出信号分离的特点,降低了噪声对周期区域的影响,使可检测输入信号的信噪比达到了一87 dB。实验表明,在时域或Poincar6映射已经无法进行分辨的情况下,该方法仍然实现了检测系统输出间歇混沌信号的有效判别。
信号检测, 混沌振子, 间歇混沌信号判别, Poincare映射, 参数敏感性
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58浏览
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76下载
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【期刊论文】基于Takagi—Sugeno模糊模型的电流跟踪型光伏并网逆变器
魏学业, 于蓉蓉, 覃庆努, 吴小进
农业工程学报,2010,26(5):240~245,-0001,():
-1年11月30日
逆变器是光伏并网发电中的关键设备,如何调整PwM控制信号的波形,输出与电网电压同频率同相位的电流,是并网逆变器设计中最重要的问题。在分析比较了光伏并网发电系统逆变器各种控制算法的基础上,推导出了单相全桥逆变电路功率开关管占空比关于并网电压和电流误差等可测量物理量的函数关系式,提出了一套基于Takagi-Sugeno模 糊模型的PWM波形产生方法。该方法采用四输入双输出的结构,将并网电压和电流误差等可测物理量作为模糊控制器 的输入量,经T-s模型模糊处理之后分别得到两组功率开关管的控制信号的占空比。该文最后以单相全桥逆变电路为例,给出了详细的仿真分析,结果显示由该方法生成的PWM控制信号较之传统滞环比较控制等,有开关频率低、硬件电路简单、谐波畸变率小等优势,可实现并网发电要求的单位功率因数。
模糊控制,, 发电,, 跟踪,, 并网发电,, 单相逆变电路,, T-s模糊模型
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73浏览
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