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The mobile underwater acoustic channel has brought a great challenge on the encoding and decoding process. The recent development of underwater acoustic processing method aims to get a lower bit error rate(BER). However, the controdiction between lower BER and real-time transmission are not well solved. In this paper, we reach a compromise between them, we combine the turbo code with the adaptive...
Mobile Underwater Acoustic Networks (MUANs) is currently a enabling technology for a wide range of applications. However, the self-localization of mobile nodes is difficult. In this paper, we propose a range-angle based self-localization scheme for MUANs. Each mobile node only communications with the anchor node which sends localization message and mobility model to the network. Ordinary nodes can...
In this paper, we proposed a new interpolation algorithm which based on the Nonsubsampled Contourlet transform. The advantages of rational function interpolation and edge-directed image interpolation are used for the image interpolation. The initial image is transformed into frequency domain through the Nonsubsampled Contourlet transform. We divide the high frequency region into the smoothing area...
The severe time-varying multipath effect of underwater acoustic (UWA) channels has posed a great challenge for shallow water communication system design. Although existing literature has demonstrated that multicarrier modulation in the form of orthogonal frequency division multiplexing(OFDM) is an effective technique to deal with severe multipath effect of UWA channels, the experiments of medium distance...
One parallel underwater acoustic network (UAN) is designed to monitor the vortex induced vibration (VIV) of free span of subsea infield pipeline in the harsh deep water environment. The architecture consist of one mater node and several source node which one kind of dense network. One underwater Orthogonal Frequency Division Multiple Access (UOFDMA) scheme is proposed to meet with the multiple access...
Cooperative communication is becoming an increasingly important issue in the underwater acoustic networks (UAN). However, existing cooperative scheme generally do not take into account the node mobility which cannot be used for the mobile UAN. A cooperative power and frequency joint allocation AF (amplify-and-forward) scheme based on game theory is proposed for mobile UAN. At first, one mobile UAN...
Subsea pipelines are very susceptible to encounter failure. One novel method based on underwater acoustic network (UAN) is proposed to monitor free span of subsea pipeline. It considers the characteristics of shallow water and complex response of subsea pipeline, defines the principle of parallel cooperative transmitting of data package and the scheme of cross layer design that take into physical...
A decision tree support vector machine (SVM) classification method based on the construction of ship-radiated noise multidimension feature vector is proposed in this paper. Aimed at three kinds of ship targets (class I submarine, class II warship and class III merchant ship) radiated noise, the subband distribution feature vectors of their 1½-spectrum and 2½-spectrum, and scale-energy feature vector...
In this paper, an improved Toeplitz matrix construction algorithm of covariance matrix is applied. This covariance matrix can be used to estimate both the incoherent and the coherent source direction with the Multiple Signal Classification (??MUSIC??) algorithm. First, the proposed algorithm uses the correlation sequences of output narrowband signals between each sensor and the reference sensor instead...
Background There are few detailed clinical reports about perihepatic lymph node (LN) assessment of hepatocellular carcinoma (HCC). The purpose of the present study was to evaluate the incidence, site, and impact on survival of LN metastasis in patients with HCC amenable to curative liver resection and routine regional lymphadenectomy. Methods From January 2001 to June 2004, a total of 523 HCC patients...
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