Noisy whisper contaminated by different types of noise are enhanced by compressive sensing method. The intelligibility performance of the enhanced whisper is measured using the short time objective index (STOI). To as...
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As the progressive effects of global warming, the yield loss caused by diseases and pests are increasing in winter wheat. It is necessary to distinguish different diseases for guiding variable rate spraying in wheat. ...
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As the progressive effects of global warming, the yield loss caused by diseases and pests are increasing in winter wheat. It is necessary to distinguish different diseases for guiding variable rate spraying in wheat. Nevertheless, it is very difficult to quantitatively identify different diseases and fertilizer-water stress by specific sensitive bands selected from multi spectral data over a large area. Conversely, hyper spectral data contain more information, and provide the potential for quantitative identification of different stresses. This study focused on identification and distinction of yellow rust, powdery mildew and fertilizer-water stress by canopy spectral reflectance. Fifteen commonly used vegetation indices were selected, and independent t-test was done to get sensitivity index for each stress. Finally, a combination index was optimally selected to distinguish the three stresses. The results showed that the integrative index (NDVI-PhRI) combining normalized difference vegetation index (NDVI) and physiological reflectance index (PhRI) could be used to identify powdery mildew and yellow rust (PM-YR). A 2-dimensional spatial coordinate was established based on the NDVI and PhRI derived from hyper spectral data, then the different stress data were displayed in the spatial coordinate and the classification boundary could be used to identify the powdery mildew and yellow rust stress. Similarly, yellow rust and fertilizer-water stress (YR-n0w0) can be distinguished by the combination index (MSR-PhRI) derived from modified simple ratio (MSR) and physiological reflectance index (PhRI);and the combination index (NRI-RVSI) derived from nitrogen reflectance index (NRI) and red-edge vegetation stress index (RVSI) was accurate to identify powdery mildew and fertilizer-water stress (PM-n0w0). For the PM-YR, YR-n0w0 and PM-n0w0 models, their verification accuracies were 83.3%, 88%, 88.75%, and the kappa accuracies were 63.41%, 74.79%, 71.43%, respectively. It indicate
A new structure of coupled-fed loop antenna con- nected with two branch radiators for eight-band LTE/WWAN (LTE700/GSM850/900/1800/1900/UMTS/LTE2300/2500) operation in the ultra-thin laptop computer is presented. The t...
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A new structure of coupled-fed loop antenna con- nected with two branch radiators for eight-band LTE/WWAN (LTE700/GSM850/900/1800/1900/UMTS/LTE2300/2500) operation in the ultra-thin laptop computer is presented. The two branch strips of the antenna are e±cient radiators and contributing multi-resonant modes to greatly enhance the bandwidth of the antenna. The proposed antenna on the top shielding metal wall of the laptop display, with a planar and compact size of 12:5 × 70 × 0:8mm3, is suitable to be embedded inside the casing of the laptop computer. The proposed antenna is fabricated and tested, and good radiation performances are obtained. Compared with the existing published antennas, the volume of the planar antenna is quite small.
To simplify the design process of coding matrices for data forwarding in two-way wireless relay networks with multiple relay nodes, a distributed cooperative transmission scheme based on cyclic delay diversity (CDD) a...
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To simplify the design process of coding matrices for data forwarding in two-way wireless relay networks with multiple relay nodes, a distributed cooperative transmission scheme based on cyclic delay diversity (CDD) and conventional space-time codes is proposed in this paper. All relay nodes are divided into several groups firstly. In each group, the relay nodes adopt CDD ways to amplify-and-forward (AF) their received signals and thereby obtain the potential diversity gains. The forwarded signals among different groups are encoded into the form of one full-rate space-time code, which can solve the problem on limited error correction ability in conventional relay schemes only using CDD ways and then further reduce the bit error rate (BER) of the distributed wireless system. Consequently, the design process for two-way relay transmissions is simplified and this method can be extended to other complicated cases. Simulation results verify that the proposed scheme is able to achieve high diversity gains and good bit error performance.
With the prevalence of group communications, how to implement secure broadcasting among group members has become one of the most important issues. Broadcasting is a point-to-multipoint communication, and secure broadc...
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Digital Rights Management (DRM) is a type of access-control technology that is used by diverse content providers to restrict the use of digital content. Enterprise Digital Rights Management (E-DRM) is an application o...
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The cooperative transmission schemes based on the amplify and forward(AF) mode have the defect of low transmission rate and the exiting full-rate cooperative transmission schemes based on space-time code design have...
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ISBN:
(纸本)9781467349994
The cooperative transmission schemes based on the amplify and forward(AF) mode have the defect of low transmission rate and the exiting full-rate cooperative transmission schemes based on space-time code design have the defect of high detection ***,this paper makes the best of linear constellation precoding(LCP) technique and cyclic delay diversity(CDD) technique,and adopts the nonorthogonal amplify and forward(NAF) mode,finally proposes a new full-rate wireless cooperative transmission scheme based on space-time-frequency code *** with the cooperative transmission schemes that only pursue the transmission rate or the BER performance,this new scheme can apply to multi-relay scenario,and has the advantages of simple structure,low signal detection complexity that does not increases with the number of relay *** of above makes the real-time data transmission service of high quality come to be possible.
The concept of three-way decisions was proposed by Yao and most of three-way decisions models use two thresholds α and β to partition the universe into three parts: the positive region POS(X), the negative region NE...
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The prevalence of aphid in winter wheat field has a significant impact on the production of winter wheat. An effective and timely forewarning of the scope and severity of the disease at a regional scale will not only ...
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