In this paper we present a classifier called bi-density twin support vector machines (BDTWSVMs) for data classification. In the training stage, BDTWSVMs first compute the relative density degrees for all training points using the intra-class graph whose weights are determined by a local scaling heuristic strategy, then optimize a pair of nonparallel hyperplanes through two smaller sized support vector machine (SVM)-typed problems. In the prediction stage, BDTWSVMs assign to the class label depending
on the kernel density degree-based distances from each test point to the two hyperplanes. BDTWSVMs not only inherit good properties from twin support vector machines (TWSVMs) but also give good description for data points. The experimental results on toy as well as publicly available datasets
indicate that BDTWSVMs compare favorably with classical SVMs and TWSVMs in terms of generalization
Multiple-Input Multiple-Output (MIMO) systems have recently been the
subject of intensive consideration in modem wireless communications as they
offer the potential of providing high capacity, thus unleashing a wide range of
applications in the wireless domain. The main feature of MIMO systems is the
use of space-time processing and Space-Time Codes (STCs). Among a variety
of STCs, orthogonal Space-Time Block Codes (STBCs) have a much simpler
decoding method, compared to other STCs
Free Space Optical Communication (FSOC) is an effective alternative technology to
meet the Next Generation Network (NGN) demands as well as highly secured (mili-
tary) communications. FSOC includes various advantages like last mile access, easy
installation, free of Electro Magnetic Interference (EMI)/Electro Magnetic Compatibil-
ity (EMC) and license free access etc. In FSOC, the optical beam propagation in the
turbulentatmosphereisseverelyaffectedbyvariousfactorssuspendedinthechannel,
geographicallocationoftheinstallationsite,terraintypeandmeteorologicalchanges.
Therefore a rigorous experimental study over a longer period becomes significant to
analyze the quality and reliability of the FSOC channel and the maximum data rate
that the system can operate since data transmission is completely season dependent.
Driven by the desire to boost the quality of service of wireless systems closer to that afforded
by wireline systems, space-time processing for multiple-input multiple-output (MIMO)
wireless communications research has drawn remarkable interest in recent years. Excit-
ing theoretical advances, complemented by rapid transition of research results to industry
products and services, have created a vibrant and growing area that is already established
by all counts. This offers a good opportunity to reflect on key developments in the area
during the past decade and also outline emerging trends.
In this thesis several asp ects of space-time pro cessing and equalization for wire-
less communications are treated. We discuss several di?erent metho ds of improv-
ing estimates of space-time channels, such as temp oral parametrization, spatial
parametrization, reduced rank channel estimation, b o otstrap channel estimation,
and joint estimation of an FIR channel and an AR noise mo del. In wireless commu-
nication the signal is often sub ject to intersymb ol interference as well as interfer-
ence from other users.
基于TMS320F28035芯片為控制核心的空間矢量異步電機(jī)變頻器 我們設(shè)計的異步電機(jī)變頻調(diào)速器以TMS320F28035芯片為控制核心，通過輸出三相PWM波控制智能功率模塊IPM驅(qū)動三相異步電機(jī)。我們使用空間矢量SVPWM算法，并對其進(jìn)行了優(yōu)化。采用檢測反電勢的方法省去了昂貴的光電編碼器，大大節(jié)省了成本。同時開創(chuàng)性的研發(fā)了自動根據(jù)運行環(huán)境調(diào)節(jié)的自適應(yīng)變頻算法，使我們的變頻調(diào)速器可以在電網(wǎng)條件惡劣的鄉(xiāng)村山區(qū)工作，由此該變頻器已被一家民用水泵生產(chǎn)企業(yè)預(yù)訂。關(guān)鍵字 變頻器 TMS320f28035 IPM SVPWM In our design, the asynchronous machine inverter based on the chip of TMS320F28035 drives the three-Phase asynchronous machine by sending three-phase PWM waves to the IPM, which is short for the Intelligent-Power-Module. The SVPWM (space vector pulse width modulation) strategy is applied to our control algorithm and we optimize it mainly in two aspects. Firstly the inverter detects the speed by measuring the Back EMF instead of installing an expensive photoelectric encoder for costs reduction.
簡介本文檔介紹了如何使用dsPIC30F數(shù)字信號控制器（Digital Signal Controller，DSC）控制正弦電流來驅(qū)動具有位置傳感器的永磁同步電機(jī)（Permanent Mag-net Synchronous Motor，PMSM）.電機(jī)控制固件使用dsPIC30F外設(shè)，而數(shù)學(xué)運算則由DSP引擎完成。為充分利用dsPIC30F的特殊DSP運算性能，固件采用C語言編寫，只有某些子程序采用匯編語言編寫。應(yīng)用特性·使用空間矢量調(diào)制（Space Vector Modulation，SVM）方法產(chǎn)生用于驅(qū)動PMSM電機(jī)各相的正弦電流·正弦電壓與PMSM電機(jī)轉(zhuǎn)子位置同步·四象限運行，可實現(xiàn)正向、反向和制動運行·基于數(shù)字比例一積分一微分（Proportional Integral Derivative，PID）控制的閉環(huán)轉(zhuǎn)速控制·相位超前技術(shù)可實現(xiàn)更寬的調(diào)速范圍·由dsPICODSC的DSP引擎實現(xiàn)小數(shù)數(shù)學(xué)運算
