摘要：Moving target detection （MTD） technique is designed to filtering out the clutters. The basis of the MTD digital signal processor is a bank of Doppler filters designed using FFT algorithm. For high pulse repetition frequency （HPRF）, it leads to a long time calculations and great complexity in hardware implementation. frequency domain detector is represented by Welch method Realized Doppler filters bank which will reduce the time calculation. The proposed method enhances the target detection capabilities by providing higher detection probabilities or lower false alarm rates. The performance of the two systems, the traditional MTD-I and Welch method are compared from the viewpoint of probability of detection （Pd）, probability of false alarm （Pfa）. Computer simulation results are presented to support the superiority of the proposed technique.

摘要：Fiber grating is a kind of new type of fiber optic light source device which has been rapidly changing in the refractive index of the core in recent years. Especially, it can realize the high precision of the external parameters by means of the special structure design and the encapsulation technology [1, 2]. In this paper, a fiber grating vibration sensor which is suitable for vibration monitoring in key areas is designed based on the technical background of vibration monitoring system. The sensor uses a single beam structure and pastes the fiber Bragg grating （FBG） to measure the vibration wavelength on the surface. When the vibration is simply harmonic vibration, the Bragg reflection wavelength will change periodically, and the periodic variation of the wavelength curve can be measured by the fiber grating demodulator, then the correctness of the experimental results is verified. In this paper, through the analysis of the data measured by the demodulator, the MATLAB software is used to verify the data, and the different frequency domains, the modes, and the phase frequency curves are obtained. The measurement range is 0Hz-100Hz, and the natural frequency is 90.6Hz.

摘要：A pilot pattern across two orthogonal frequency division multiplexing OFDM symbols with a special structure is designed for the channel estimation of OFDM systems with inphase and quadrature IQ imbalances at the receiver.A high-efficiency time-domain TD least square LS channel estimator and a low-complexity frequency-domain Gaussian elimination GE equalizer are proposed to eliminate IQ *** former estimator can significantly suppress channel noise by a factor N/L＋1 over the existing frequency-domain FD LS where N and L＋1 are the total number of subcarriers and the length of cyclic prefix and the proposed GE requires only 2N complex multiplications per OFDM *** results show that by exploiting the TD property of the channel the proposed TD-LS channel estimator obtains a significant signal-to-noise ratio gain over the existing FD-LS one whereas the proposed low-complexity GE compensation achieves the same bit error rate BER performance as the existing LS one.

摘要：The seakeeping performance of a luxury cruise ship was evaluated during the concept design *** comparing numerical predictions based on 3-D linear potential flow theory in the frequency domain with the results of model tests, it was shown that the 3-D method predicted the seakeeping performance of the luxury cruise ship *** on the model, the seakeeping features of the luxury cruise ship were analyzed, and then the influence was seen of changes to the primary design parameters (center of gravity, inertial radius, etc.).Based on the results, suggestions were proposed to improve the choice of parameters for luxury cruise ships during the concept design *** should improve seakeeping performance.