BeiDou-3 navigation satellite system was officially opened in 2020.While bringing high-performance services to people around the world,the navigation system requires well-designed BeiDou antennas.In this paper,we prop...BeiDou-3 navigation satellite system was officially opened in 2020.While bringing high-performance services to people around the world,the navigation system requires well-designed BeiDou antennas.In this paper,we propose a wideband circularly polarized high-performance BeiDou antenna.The antenna realizes wideband circularly polarized radiation through a four-port sequential feed network,and the phase imbalance of the feed network from 1.05 to 1.80 GHz is less than 7°.The manufactured antenna demonstrates a return loss of more than 13 dB and an axial ratio<3 dB over the entire global navigation satellite system(GNSS)frequency band.The right-handed circular polarization(RHCP)gain of the proposed antenna is greater than 4 dB in the GNSS low-frequency band and can reach more than 7.1 dB in the high-frequency band.Dimension of the proposed antenna is 120 mm×120 mm×20 mm,i.e.,0.54λo×0.54λo×0.09λo,whereλo is the wavelength of the center frequency.The proposed antenna connected to a GNSS receiver has tracked 12 BeiDou satellites with C/N0 ratios of GNSS signals greater than 30 dB.Such a high-performance antenna provides a basis for high-quality positioning services.展开更多
In the paper, a method of building mathematic model employing genetic multilayer feed forward neural network is presented, and the quantitative relationship of chemical measured values and near-infrared spectral data ...In the paper, a method of building mathematic model employing genetic multilayer feed forward neural network is presented, and the quantitative relationship of chemical measured values and near-infrared spectral data is established. In the paper, quantitative mathematic model related chemical assayed values and near-infrared spectral data is established by means of genetic multilayer feed forward neural network, acquired near-infrared spectral data are taken as input of network with the content of five kinds of fat acids tested from chemical method as output, weight values of multilayer feed forward neural network are trained by genetic algorithms and detection model of neural network of soybean is built. A kind of multilayer feed forward neural network trained by genetic algorithms is designed in the paper. Through experiments, all the related coefficients of five fat acids can approach 0.9 which satisfies the preliminary test of soybean breeding.展开更多
This paper presents the pathological voice detection and classification techniques using signal processing based methodologies and Feed Forward Neural Networks(FFNN).The important pathological voices such as Autism Sp...This paper presents the pathological voice detection and classification techniques using signal processing based methodologies and Feed Forward Neural Networks(FFNN).The important pathological voices such as Autism Spectrum Disorder(ASD)and Down Syndrome(DS)are considered for analysis.These pathological voices are known to manifest in different ways in the speech of children and adults.Therefore,it is possible to discriminate ASD and DS children from normal ones using the acoustic features extracted from the speech of these subjects.The important attributes hidden in the pathological voices are extracted by applying different signal processing techniques.In this work,three group of feature vectors such as perturbation measures,noise parameters and spectral-cepstral modeling are derived from the signals.The detection and classification is done by means of Feed For-ward Neural Network(FFNN)classifier trained with Scaled Conjugate Gradient(SCG)algorithm.The performance of the network is evaluated by finding various performance metrics and the the experimental results clearly demonstrate that the proposed method gives better performance compared with other methods discussed in the literature.展开更多
A kind of second order algorithm--recursive approximate Newton algorithm was given by Karayiannis. The algorithm was simplified when it was formulated. Especially, the simplification to matrix Hessian was very reluct...A kind of second order algorithm--recursive approximate Newton algorithm was given by Karayiannis. The algorithm was simplified when it was formulated. Especially, the simplification to matrix Hessian was very reluctant, which led to the loss of valuable information and affected performance of the algorithm to certain extent. For multi layer feed forward neural networks, the second order back propagation recursive algorithm based generalized cost criteria was proposed. It is proved that it is equivalent to Newton recursive algorithm and has a second order convergent rate. The performance and application prospect are analyzed. Lots of simulation experiments indicate that the calculation of the new algorithm is almost equivalent to the recursive least square multiple algorithm. The algorithm and selection of networks parameters are significant and the performance is more excellent than BP algorithm and the second order learning algorithm that was given by Karayiannis.展开更多
In the oil industry, the productivity of oil wells depends on the performance of the sub-surface equipment system. These systems often have problems stemming from sand, corrosion, internal pressure variation, or other...In the oil industry, the productivity of oil wells depends on the performance of the sub-surface equipment system. These systems often have problems stemming from sand, corrosion, internal pressure variation, or other factors. In order to ensure high equipment performance and avoid high-cost losses, it is essential to identify the source of possible failures in the early stage. However, this requires additional maintenance fees and human power. Moreover, the losses caused by these problems may lead to interruptions in the whole production process. In order to minimize maintenance costs, in this paper, we introduce a model for predicting equipment failure based on processing the historical data collected from multiple sensors. The state of the system is predicted by a Feed-Forward Neural Network (FFNN) with an SGD and Backpropagation algorithm is applied in the training process. Our model’s primary goal is to identify potential malfunctions at an early stage to ensure the production process’ continued high performance. We also evaluated the effectiveness of our model against other solutions currently available in the industry. The results of our study show that the FFNN can attain an accuracy score of 97% on the given dataset, which exceeds the performance of the models provided.展开更多
This paper describes the application of principal component analysis (PCA) and artificial neural network (ANN) to predict the air pollutant index (API) within the seven selected Malaysian air monitoring stations in th...This paper describes the application of principal component analysis (PCA) and artificial neural network (ANN) to predict the air pollutant index (API) within the seven selected Malaysian air monitoring stations in the southern region of Peninsular Malaysia based on seven years database (2005-2011). Feed-forward ANN was used as a prediction method. The feed-forward ANN analysis demonstrated that the rotated principal component scores (RPCs) were the best input parameters to predict API. From the 4 RPCs, only 10 (CO, O3, PM10, NO2, CH4, NmHC, THC, wind direction, humidity and ambient temp) out of 12 prediction variables were the most significant parameters to predict API. The results proved that the ANN method can be applied successfully as tools for decision making and problem solving for better atmospheric management.展开更多
为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击...为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击过程,研究从天线极化方向讨论天线的雷击耦合特性以及天线单元连接由不同功分器构成的馈电网络进行组阵时阵列天线的雷击耦合特性。发现天线的耦合电压峰值与极化旋转角呈现线性关系,天线在垂直极化下的耦合电压比在水平极化下的耦合电压大得多;同时,对于通信塔上GSM频段的微带阵列天线,阵列天线的耦合电压受到馈电网络的影响,采用由威尔金森功分器构成的馈电网络进行组阵比采用由T型功分器构成的馈电网络进行组阵阵列天线的耦合电压更小。展开更多
文摘BeiDou-3 navigation satellite system was officially opened in 2020.While bringing high-performance services to people around the world,the navigation system requires well-designed BeiDou antennas.In this paper,we propose a wideband circularly polarized high-performance BeiDou antenna.The antenna realizes wideband circularly polarized radiation through a four-port sequential feed network,and the phase imbalance of the feed network from 1.05 to 1.80 GHz is less than 7°.The manufactured antenna demonstrates a return loss of more than 13 dB and an axial ratio<3 dB over the entire global navigation satellite system(GNSS)frequency band.The right-handed circular polarization(RHCP)gain of the proposed antenna is greater than 4 dB in the GNSS low-frequency band and can reach more than 7.1 dB in the high-frequency band.Dimension of the proposed antenna is 120 mm×120 mm×20 mm,i.e.,0.54λo×0.54λo×0.09λo,whereλo is the wavelength of the center frequency.The proposed antenna connected to a GNSS receiver has tracked 12 BeiDou satellites with C/N0 ratios of GNSS signals greater than 30 dB.Such a high-performance antenna provides a basis for high-quality positioning services.
基金Heilongjiang Natural Science Foundation (F0318).
文摘In the paper, a method of building mathematic model employing genetic multilayer feed forward neural network is presented, and the quantitative relationship of chemical measured values and near-infrared spectral data is established. In the paper, quantitative mathematic model related chemical assayed values and near-infrared spectral data is established by means of genetic multilayer feed forward neural network, acquired near-infrared spectral data are taken as input of network with the content of five kinds of fat acids tested from chemical method as output, weight values of multilayer feed forward neural network are trained by genetic algorithms and detection model of neural network of soybean is built. A kind of multilayer feed forward neural network trained by genetic algorithms is designed in the paper. Through experiments, all the related coefficients of five fat acids can approach 0.9 which satisfies the preliminary test of soybean breeding.
文摘This paper presents the pathological voice detection and classification techniques using signal processing based methodologies and Feed Forward Neural Networks(FFNN).The important pathological voices such as Autism Spectrum Disorder(ASD)and Down Syndrome(DS)are considered for analysis.These pathological voices are known to manifest in different ways in the speech of children and adults.Therefore,it is possible to discriminate ASD and DS children from normal ones using the acoustic features extracted from the speech of these subjects.The important attributes hidden in the pathological voices are extracted by applying different signal processing techniques.In this work,three group of feature vectors such as perturbation measures,noise parameters and spectral-cepstral modeling are derived from the signals.The detection and classification is done by means of Feed For-ward Neural Network(FFNN)classifier trained with Scaled Conjugate Gradient(SCG)algorithm.The performance of the network is evaluated by finding various performance metrics and the the experimental results clearly demonstrate that the proposed method gives better performance compared with other methods discussed in the literature.
文摘A kind of second order algorithm--recursive approximate Newton algorithm was given by Karayiannis. The algorithm was simplified when it was formulated. Especially, the simplification to matrix Hessian was very reluctant, which led to the loss of valuable information and affected performance of the algorithm to certain extent. For multi layer feed forward neural networks, the second order back propagation recursive algorithm based generalized cost criteria was proposed. It is proved that it is equivalent to Newton recursive algorithm and has a second order convergent rate. The performance and application prospect are analyzed. Lots of simulation experiments indicate that the calculation of the new algorithm is almost equivalent to the recursive least square multiple algorithm. The algorithm and selection of networks parameters are significant and the performance is more excellent than BP algorithm and the second order learning algorithm that was given by Karayiannis.
文摘In the oil industry, the productivity of oil wells depends on the performance of the sub-surface equipment system. These systems often have problems stemming from sand, corrosion, internal pressure variation, or other factors. In order to ensure high equipment performance and avoid high-cost losses, it is essential to identify the source of possible failures in the early stage. However, this requires additional maintenance fees and human power. Moreover, the losses caused by these problems may lead to interruptions in the whole production process. In order to minimize maintenance costs, in this paper, we introduce a model for predicting equipment failure based on processing the historical data collected from multiple sensors. The state of the system is predicted by a Feed-Forward Neural Network (FFNN) with an SGD and Backpropagation algorithm is applied in the training process. Our model’s primary goal is to identify potential malfunctions at an early stage to ensure the production process’ continued high performance. We also evaluated the effectiveness of our model against other solutions currently available in the industry. The results of our study show that the FFNN can attain an accuracy score of 97% on the given dataset, which exceeds the performance of the models provided.
文摘This paper describes the application of principal component analysis (PCA) and artificial neural network (ANN) to predict the air pollutant index (API) within the seven selected Malaysian air monitoring stations in the southern region of Peninsular Malaysia based on seven years database (2005-2011). Feed-forward ANN was used as a prediction method. The feed-forward ANN analysis demonstrated that the rotated principal component scores (RPCs) were the best input parameters to predict API. From the 4 RPCs, only 10 (CO, O3, PM10, NO2, CH4, NmHC, THC, wind direction, humidity and ambient temp) out of 12 prediction variables were the most significant parameters to predict API. The results proved that the ANN method can be applied successfully as tools for decision making and problem solving for better atmospheric management.
文摘为研究当无线基站通信塔上避雷针遭受雷击时位于闪电通道附近天线的耦合效应,基于CST Studio Suite电磁仿真软件建立闪电通道-通信塔和工作在中国移动通信GSM1800/1900频段下的微带阵列天线的仿真模型。基于闪电回击电磁模型的继后回击过程,研究从天线极化方向讨论天线的雷击耦合特性以及天线单元连接由不同功分器构成的馈电网络进行组阵时阵列天线的雷击耦合特性。发现天线的耦合电压峰值与极化旋转角呈现线性关系,天线在垂直极化下的耦合电压比在水平极化下的耦合电压大得多;同时,对于通信塔上GSM频段的微带阵列天线,阵列天线的耦合电压受到馈电网络的影响,采用由威尔金森功分器构成的馈电网络进行组阵比采用由T型功分器构成的馈电网络进行组阵阵列天线的耦合电压更小。
