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This paper addresses a novel direction-of-arrival (DOA) estimation method for noncircular sources, such as BPSK and OQPSK modulated signals, in the presence of multipath propagation. The group steering vector of each coherent group is obtained first, and then both forward and backward group steering vectors are exploited to estimate the DOAs of the corresponding group by constructing a composite matrix...
An out-of-core domain decomposition method (DDM) based on parallel higher-order Method of Moment (MoM) is present, herein referred to as OOC-DDM, for the radiation patterns of electrically large problems. This algorithm allows the matrix be stored on the hard disk when the matrix is too large to fit in the main memory of the computing platform. The using of higher-order basis functions can further...
This paper focuses on the simulation of electrically large slotted waveguide array using accurate method. The main challenges are the lack of matched terminators and the enormous time and memory space consumption. Mode match method is used to construct the matched terminators, while the parallel high-order MoM is chosen to extend the capacity of MoM. Finally, a Ka-band waveguide array with 2068 narrow-wall...
A novel communication avoiding LU (CALU) algorithm is presented for solving matrix equations of Method of Moments (MoM). By using a new pivoting scheme, the communication pattern is changed in parallel LU decomposition. Matrix equations of MoM with three representative basis functions are solved. With the given CALU algorithm, one can significantly reduce the computation time from available commercial...
In this paper, based on equivalent-principle, a parallel hybrid Finite Difference Time Domain (FDTD) and Multilevel Fast Multipole Algorithm (MLFMA) is introduced to analyze the radiation characteristic of an airborne antenna array. The numerical convergence of results is achieved through several iterations. Numerical results show that it can greatly reduce the memory requirement and time consumption.
Real-time performance can be greatly improved, if the early recognition is implemented. In this paper, a dynamic hand gesture early recognition system is proposed. The system can recognize the gesture before it is completed. Our method is based on the Hidden Semi-Markov Models. Three-dimensional information of the gesture trajectory collected by leapmotion is the main data we used. Experiments on...
To improve the coupling efficiency of Quantum Well Infrared Photo-detector (QWIP), a new grating was proposed. By optimizing the grating, it can work in 3∼5µm and realize an enhanced peak at 4.5µm. With the uniform result of simulation and experiment, an optimizing metallic grating was designed.
The main objective of this work is to assess the possibility of improving the achievable image quality using synthetic aperture (SA) approach and to evaluate the performance of the modified algorithm. The modified algorithm is based on the coherent summation of back-scattered RF echo signals with weights calculated for each point and for all possible combinations of transmit-receive pairs. Weights...
The Total Focus Method (TFM) is a post-processing algorithm which uses all elements in the array to focus in both transmission and reception at every image point. The time-domain signals is captured in a process termed Full Matrix Capture (FMC). In this paper, the main objective is to research the effects of directivity function on the TFM. The TFM algorithm is based on the FMC data with weights calculated...
The Full Matrix Capture (FMC) method can provide the original complete information which is detected by the ultrasonic array and can recover with the Total Focusing Method (TFM). This technique has better detection sensitivity and resolution relative to conventional scanning method and is valuable for improving the quality and reliability of industrial non-destructive testing. However, it has low...
A circular array mounted on coated cylinders is considered and its theoretical accurate solutions of pattern synthesis are derived. Based on the sound scattering theory, the sound field can be calculated easily. Since the criterion is to minimize the square error between the desired and synthesized beampattern, the optimal weighting vector, the output beam, and the minimum square error can be all...
Application of fiber laser array for free-space communication has great predominance. This paper studies the far field properties of the fiber laser phased array. An analytical expression for the far field pattern is obtained based on the Huygens-Fresnel principle. The far field properties, the scanning/steering angle range, and the angular resolution are numerically studied. It is found that for...
In this article, a reduced vector sensor with six current dipoles located in a distributed way was proposed. Adopting ESPRIT and Eigen-value Decomposition of the space time matrix we constructed, the elevation, azimuth and the polarization state of the arrival can be estimated via the distributed reduced vector sensor considering about the short dipole patterns. The estimation errors of elevation,...
Self-organized coherent fiber laser array using fused fiber component is analyzed. We numerically investigate the output stability, the power scalability, and the phase-locking property. The results demonstrate that if the system is driven properly, with appropriate cavity length, fiber grating reflectivity and pump gain, the fiber laser array is able to achieve stable output power and the array size...
Cellular automata (CA) or linear feedback shift register (LFSR) architecture is widely used in pseudorandom generator of applied cryptography. The paper proposes a multi-dimensional and multi-rank pseudorandom generator combined the CA algorithm and LFSR architecture. In order to test the feasibility of the design, we research on feasibility and efficient of the algorithm by using three bit tests...
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