一维测向算法的目的是估计空间信号源的方位角（即1-DOA估计）,从而确定辐射源的方向。DML（Determined Maximum Likelihood）是一种针对确定性窄带信号的参数进行最大似然估计的算法,理论上具有估计精度高、抗相干及抗噪性强等优点,但...一维测向算法的目的是估计空间信号源的方位角（即1-DOA估计）,从而确定辐射源的方向。DML（Determined Maximum Likelihood）是一种针对确定性窄带信号的参数进行最大似然估计的算法,理论上具有估计精度高、抗相干及抗噪性强等优点,但其目标函数不易求解。提出了一种FP-SO-DML算法,通过FPSO对DML目标函数进行高精度、低复杂度的全局寻优。结合FFB（Fast FilterBank）滤波,将宽带信号分解为不同频点上的窄带信号,再选取某一频点上的信号作为处理对象,通过FPSO-DML算法完成对宽带信号的一维测向。仿真证明了提出算法即使在存在相干信源的情况下仍然可以完成高精度的1-DOA估计。展开更多
Channelization typically realized by digital filter banks is an important topic in high frequency(HF) communication and software defined radios(SDR) areas. Channelization has a rigorous requirement for the characteris...Channelization typically realized by digital filter banks is an important topic in high frequency(HF) communication and software defined radios(SDR) areas. Channelization has a rigorous requirement for the characteristic of frequency response, e.g., steep transitional band and sharp decay. To address this issue, we investigated the feasibility and implementation of applying fast filter bank(FFB) in channelization in this paper. We analyzed the butterfly structure of FFB similar with fast Fourier transform(FFT), in which prototype sub-filters are cascaded to achieve a low complexity. Hence, it is suitable for designing filter bank with steep transitional band and sharp decay in stop-band. Moreover, we designed a pipelined structure of FFB to achieve a balance between area and performance. Design example shows that FFB has lower computational complexity compared with the other filter banks.展开更多
Robot technology is a very promising technology for agricultural sector, but the existing industrial robot could not deliver the above-mentioned criteria. Industrial robot mainly uses high voltage electrical power, wh...Robot technology is a very promising technology for agricultural sector, but the existing industrial robot could not deliver the above-mentioned criteria. Industrial robot mainly uses high voltage electrical power, which is not available at field and outdoor operation. The only available and reliable power is a hydraulic from the tractor. The harvester robot consumes the hydraulic power from the tractor and at the same time the tractor can be used as a traveling device for the robot. This paper describes the study on the development of autonomous tractor for the oil palm harvester. The development took considerations on the design of the electro-hydraulic system and the control software for the robot structure to be flexible enough to operate in plantation environment.展开更多
The indirect electrochemical reduction of Indanthrene Brilliant Green FFB （IBG） was investigated in detail by cyclic voltammetry and electrolytic experiments.Triethanolamine （TEA） was used as ligand to form elec-t...The indirect electrochemical reduction of Indanthrene Brilliant Green FFB （IBG） was investigated in detail by cyclic voltammetry and electrolytic experiments.Triethanolamine （TEA） was used as ligand to form elec-trochemically active Fe（III）-complexes in alkaline solution.The effects of operating parameters including reaction temperature,current density,concentration of NaOH and Fe（III）-TEA mediator had been studied by orthogonal ex-periments and the mechanism of radicals on electrochemical reduction was discussed.The cyclic voltammetry ex-perimental results show that Fe（III）-TEA complexes are well suited for the indirect electrochemical reduction of IBG.The electrolytic experiments show that high current efficiency （49.9%） can be successfully achieved under op-timized conditions and the current density is found to be the main influence factor.展开更多
The need to mechanize major field operations that are labor intensive in oil palm industry of Malaysia has led to the study on agricultural machine automation.In general,study was on machine automation to reduce the n...The need to mechanize major field operations that are labor intensive in oil palm industry of Malaysia has led to the study on agricultural machine automation.In general,study was on machine automation to reduce the number of workers required for harvesting as well as to provide comfortable ergonomic for the operator of oil palm harvester.The objective of the study was to perform interfacing between the oil palm tree and hardware(harvester)as well as to compare the harvesting efficiency between the mechanical and automated manipulator.Kinematic analysis was calculated based on the D-H configuration for the position and orientation of harvester arm using high resolution webcam and ultrasonic sensor to obtain 3D coordinates required by the D-H notations.PIC Circuit Board(PCB)design and fabrication as well as testing and implementation of concept of camera vision operation system for FFB harvester with fully developing a Graphical User Interface(GUI)was conducted to assist the automation of the harvester manipulator.The automation of 5DOF manipulator harvester operation proves to be faster than the manually operated mechanical harvester with an approximation of 60 percent significant decrease in speed of the manipulator with 70 percent of accuracy.展开更多
A scheme to design a simultaneous multichannel receiver is proposed to process multichannel signals in parallel, which is achieved by exploiting the attractive characteristics of a fast filter bank（ FFB）, such as ca...A scheme to design a simultaneous multichannel receiver is proposed to process multichannel signals in parallel, which is achieved by exploiting the attractive characteristics of a fast filter bank（ FFB）, such as cascaded structure, high frequency selectivity and lowcomputational complexity. Based on the minimization of the objective function, quantified in terms of the total number of multiplications required, subject to prescribed allowable ripples in the passband and stopband, the impulse response coefficients of the prototype filter in each stage are obtained to meet the requirements of the overall specifications for each channel at the receiver side. Simulations and experimental results on the frequency modulation（ FM） broadcast mutlichannel signal receiving system with the FM range from88 to 108 MHz, built upon the proposed FFB structure, are performed to verify its performance. Those results indicate that the proposed scheme is efficient in FM audio indexing applications and has a lower computational complexity, which is approximately 66. 4% of the weighted overlap and add（ WOLA） filter banks based solution.展开更多
文摘一维测向算法的目的是估计空间信号源的方位角（即1-DOA估计）,从而确定辐射源的方向。DML（Determined Maximum Likelihood）是一种针对确定性窄带信号的参数进行最大似然估计的算法,理论上具有估计精度高、抗相干及抗噪性强等优点,但其目标函数不易求解。提出了一种FP-SO-DML算法,通过FPSO对DML目标函数进行高精度、低复杂度的全局寻优。结合FFB（Fast FilterBank）滤波,将宽带信号分解为不同频点上的窄带信号,再选取某一频点上的信号作为处理对象,通过FPSO-DML算法完成对宽带信号的一维测向。仿真证明了提出算法即使在存在相干信源的情况下仍然可以完成高精度的1-DOA估计。
基金supported in part by the National Natural Science Foundation of China under Grant 61601477, and 61601480
文摘Channelization typically realized by digital filter banks is an important topic in high frequency(HF) communication and software defined radios(SDR) areas. Channelization has a rigorous requirement for the characteristic of frequency response, e.g., steep transitional band and sharp decay. To address this issue, we investigated the feasibility and implementation of applying fast filter bank(FFB) in channelization in this paper. We analyzed the butterfly structure of FFB similar with fast Fourier transform(FFT), in which prototype sub-filters are cascaded to achieve a low complexity. Hence, it is suitable for designing filter bank with steep transitional band and sharp decay in stop-band. Moreover, we designed a pipelined structure of FFB to achieve a balance between area and performance. Design example shows that FFB has lower computational complexity compared with the other filter banks.
文摘Robot technology is a very promising technology for agricultural sector, but the existing industrial robot could not deliver the above-mentioned criteria. Industrial robot mainly uses high voltage electrical power, which is not available at field and outdoor operation. The only available and reliable power is a hydraulic from the tractor. The harvester robot consumes the hydraulic power from the tractor and at the same time the tractor can be used as a traveling device for the robot. This paper describes the study on the development of autonomous tractor for the oil palm harvester. The development took considerations on the design of the electro-hydraulic system and the control software for the robot structure to be flexible enough to operate in plantation environment.
基金Supported by the National Basic Research Program of China （2003CCA01300） the National Natural Science Foundation of China （20876151）
文摘The indirect electrochemical reduction of Indanthrene Brilliant Green FFB （IBG） was investigated in detail by cyclic voltammetry and electrolytic experiments.Triethanolamine （TEA） was used as ligand to form elec-trochemically active Fe（III）-complexes in alkaline solution.The effects of operating parameters including reaction temperature,current density,concentration of NaOH and Fe（III）-TEA mediator had been studied by orthogonal ex-periments and the mechanism of radicals on electrochemical reduction was discussed.The cyclic voltammetry ex-perimental results show that Fe（III）-TEA complexes are well suited for the indirect electrochemical reduction of IBG.The electrolytic experiments show that high current efficiency （49.9%） can be successfully achieved under op-timized conditions and the current density is found to be the main influence factor.
文摘The need to mechanize major field operations that are labor intensive in oil palm industry of Malaysia has led to the study on agricultural machine automation.In general,study was on machine automation to reduce the number of workers required for harvesting as well as to provide comfortable ergonomic for the operator of oil palm harvester.The objective of the study was to perform interfacing between the oil palm tree and hardware(harvester)as well as to compare the harvesting efficiency between the mechanical and automated manipulator.Kinematic analysis was calculated based on the D-H configuration for the position and orientation of harvester arm using high resolution webcam and ultrasonic sensor to obtain 3D coordinates required by the D-H notations.PIC Circuit Board(PCB)design and fabrication as well as testing and implementation of concept of camera vision operation system for FFB harvester with fully developing a Graphical User Interface(GUI)was conducted to assist the automation of the harvester manipulator.The automation of 5DOF manipulator harvester operation proves to be faster than the manually operated mechanical harvester with an approximation of 60 percent significant decrease in speed of the manipulator with 70 percent of accuracy.
基金The National Natural Science Foundation of China(No.61201173,61271058,61401094)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20110092110008)+1 种基金the Natural Science Foundation of Jiangsu Province(No.SBK201140040,BK2011060,BK20140645)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China
文摘A scheme to design a simultaneous multichannel receiver is proposed to process multichannel signals in parallel, which is achieved by exploiting the attractive characteristics of a fast filter bank（ FFB）, such as cascaded structure, high frequency selectivity and lowcomputational complexity. Based on the minimization of the objective function, quantified in terms of the total number of multiplications required, subject to prescribed allowable ripples in the passband and stopband, the impulse response coefficients of the prototype filter in each stage are obtained to meet the requirements of the overall specifications for each channel at the receiver side. Simulations and experimental results on the frequency modulation（ FM） broadcast mutlichannel signal receiving system with the FM range from88 to 108 MHz, built upon the proposed FFB structure, are performed to verify its performance. Those results indicate that the proposed scheme is efficient in FM audio indexing applications and has a lower computational complexity, which is approximately 66. 4% of the weighted overlap and add（ WOLA） filter banks based solution.
