Advanced Materials Research Vols. 765-767

Abstract: nverse synthetic aperture radar (ISAR) is a kind of imaging radar with high capability. It plays an important role in military applications, such as target classification, recognition, identification and accurate weapon navigation. This paper establishes a simulation model of jamming for ISAR system based on the principle of ISAR imaging. Then, the several typical of noise modulation jamming experiments for ISAR are carried out. The simulation results are analysed through evaluating the jamming effect based on the entropy concept.

Abstract: EPS network is the future direction of mobile network, and voice service is still important in the EPS network. In the conventional 2G/3G mobile communication, voice service is provided by circuit switching in the CS domain. As the LTE core network provides the access to high-speed and lower latency wireless packet data on the air interface 3GPP retains the PS domain rather than the CS domain in designing the core network. And voice service which is included in the packet domain is available through VOIP. To ensure high-quality voice services, 3GPP proposes two solutions: CSFB and SRVCC. Each option has its own applied conditions, advantages and disadvantages. This article first introduces EPC network framework and the functions of its core functional entities. Then the network framework and voice processing of the two programs (CSFB and SRVCC) are compared. At last, a conclusion of advantages and disadvantages of the two programs is given, and it will lay the basis for different options.

Abstract: Pertaining to the study on voice recognition issue, the characteristic selection study on voice signal is described via Relief Algorithm in this paper, it is started from 24-dimensional MFCC parameters to find out the most important MFCC parameters in the voice signal, under the condition that the recognition ratio doesnt change greatly, the optimized combination is performed for 24-dimensional MFCC parameters to provide a new orientation for characteristic of voice recognition.

Abstract: The optimal fractional order is got for image denoising by 2-D fractional wavelet transform (FWT). But, the actual application environment is complex, and the input image has already been polluted by unknown noise frequently in the process of capture and transmission. And it's impossible to get the optimal fractional order on the basis of the objective evaluation standard in existence. Therefore, in view of the unknown image noise, a method to get the estimated value of optimal fractional order is put forward. Firstly, new objective evaluation standards for image denoising in fractional wavelet domain are defined, and its optimal value is obtained based on noise estimation. Then the optimal estimated fractional order is got. The experiment results show that, the optimal order of 2-D FWT can be selected reasonably by the proposed method and the unknown image noise can be filtered effectively in the estimated optimal fractional wavelet domain.

Abstract: Due to the complex propagation caused by the multipath effect, the time-varying characteristics, the frequency selective fading and other factors of the wireless communication, consequently, the channel estimation is an important component in the receiving system with high performance. In this paper, comparisons with regard to the mean-square error and bit error rate are made in the WPDM-CDMA system based on two typical channel estimation algorithms, including the least squares error (LS) algorithm and the minimum mean-square error (MMSE) algorithm.

Abstract: In this paper, firstly, we introduce the way of Cellular Neural Network (CNN). Secondly, we use different way to process the image by the CNN. Thirdly, we observe these processed images. We can find some regulars about the oasis. We get the size of the oasis. Then, we can find the environment is good or poor. If the size of oasis is small, we must enhance protecting about the environment. Then, we can research a prediction method to some images.

Abstract: In this paper, a kind of transform has been given for an image that switches to a matrix. A Radar image is an RGB image. An RGB image is usually represented to three layers: Red, Green, and Blue. Each layer can be changed to a matrix. We give a way to transform the three layers to one matrix. All image information will be remained. According to this way, the hail cloud radar image had been transformed to a matrix. The information of hail will been remain in this matrix.

Abstract: Compressive sensing (CS) is an emerging technology which can capture and represent compressible signal at a rate below the Nyquist rate of sampling. In this paper, the perceptual compressive sensing scheme is proposed. Firstly, two-dimentional Discrete Wavelet Transform (DWT) is applied for sparse representation and the perceptual feature is calculated for the different wavelet coefficient. Then the coefficients are partitioned into four blocks. According to the perceptual features, the perceptual weighted CS measurement is performed for different block respectively. Experimental results show that the proposed scheme achieves higher subjective and objective performance compared with the algorithm without the human vision system. With 40% coefficients retained, the image can still be recovered with considerably objective and subjective quality.

Abstract: Traffic signal lights are generally composed by digital indicator and direction indicator. Its identification and classification is to analysis image content on the base of the semaphores characteristics, to identify the semaphores goals and classify them, including pre-processing, positioning, segmentation and classification. Based on image preprocessing, global threshold processing is used in the HSI color space to find the location of traffic signal lights; then to get each indicator through the projection method dividing; finally to distinguish digital processing and direction indicator by target detection algorithm based on the shape features of traffic signal lights. Simulation experiments show that the algorithm is reliable and executes efficiently with high accuracy.

Abstract: The fourth generation mobile communication system is a high-speed broadband wireless communication system, it needs MIMO and OFDM technology which have high spectral efficiency and suitable for a multi-path fading channel. Because the MIMO-OFDM system is still an multi-carrier modulation system, the main drawback is the high PAPR value. This paper proposed an improved algorithm based on optimized PTS to reduce PAPR in STBC MIMO-OFDM system. The simulation results show that the improved algorithm can effectively reduce the PAPR value and do not increase the amount of computation in STBC MIMO-OFDM system.