传感器网络高频数据采集算法

随着传感器网络技术的发展,传感器被广泛地应用到各个领域。由于传统的传感器数据采集采用串行采集算法,采集速率较低,严重影响了整个传感器网络的效率。针对此问题,本文提出了一种并行的高频数据采集算法,批量进行数据采集,并改进了设备响应等待时间机制。通过大量的实验数据进行对比分析及可视化处理,并进行验证分析,最终结果表明该算法在保证数据采集正确率的同时,大幅提高了数据采集的速率,并且数据采集的对象越多,提高的越明显。     

卷积神经网络识别侧扫声呐影像的研究

卷积神经网络是当前应用最广泛的图像识别算法,利用大量数据对网络进行训练,即可达到快速、高效地对图像进行识别的目的 .由于卷积神经网络结构众多,且同一数据在不同网络表现也不尽相同,为了选择适用于分析沉船声呐数据的网络,使用Python搭建LeNet 5、AlexNet、VGG、GoogLeNet、ResNet系列(Res...     

VBF水下传感器网络路由协议的路径优化与模拟

针对水下传感器网络节点的移动性,以基本VBF(Vector-Based Forwarding Protocol)路由协议为基础,提出了1种适用于水下移动传感器节点的路径优化算法.为了验证此路径优化算法的有效性,分别对基本VBF算法和改进的VBF算法进行了3个模拟实验;从数据包接收成功率和网络负载两方面分析比较了实验模拟结果.比较结果可以看出:文中提出的路径优化的VBF路由协议的数据包成功接收率要优于VBF路由协议,降低了网络负载,并且该优化算法实现简单,不需要增加额外的网络延迟时间.     

基于蚁群算法的水下传感网网络生存期延长策略研究

随着海洋强国战略的推进和实施,水下传感器网络广泛应用于海洋资源探测、污染监测、辅助导航和水下军事侦察等领域,具有十分重要的意义。由于水下传感器所携电池充电或更换困难,如何减小传输能耗、在传感器能量受限的情况下提升网络生存期是亟须解决的关键问题之一。据此,提出了一种动态蚁群路由算法,考虑了每次传输后的节点剩余能量,作为路径优化的条件之一,基于蚁群算法在每次传输中选择最优路径,并在每次传输完成后更新路由表,让更多的节点参与信息传输,以提高节点的利用率。仿真结果表明：动态蚁群路由算法同时兼顾了能耗平衡和最小传输能耗,大大提高了网络生存期。分析结果对水下传感器网络的路由协议设计有一定的参考意义。     

基于贝叶斯分类器的多普勒天气雷达海浪回波识别和效果检验

为了提升雷达数据质量，减少海浪回波对临近预报和数值天气预报模式的雷达数据同化的不利影响，因此需要对海浪回波进行识别和去除。识别算法主要为统计获得先验概率，分析海浪和降水回波特征分布得到似然函数，再经过贝叶斯分类器来达到识别的目的。在本次算法识别过程中65个样本数据试验的临界成功指数I_CS达到了0.692，结果表明利用贝叶斯分类器对海浪回波的识别，具有较好的识别效果，能一定程度降低海浪回波误判为降水回波的错误，提高雷达数据质量。     

海洋监测传感器网络概念与应用探讨

通过介绍国外在军用和民用领域海洋监测传感器网络的应用情况,结合我国海洋监测技术发展的现状,分析了传感器网络在海洋监测中应用的概念和内容,并对应用技术研究问题进行了探讨。     

海洋水声传感器网络路由机制研究

水声传感器网络是近年来的新兴应用研究领域,路由机制是其网络协议栈的核心内容,用于在水下建立一条数据传输路径。由于水下应用场景与水声通信环境的特殊性,导致陆上传感器网络的路由机制难以直接应用到水下。文章深入分析了海洋水声传感器网络的应用场景,将其归结为水底的二维平面形式与水下三维立体形式。对于二维平面形式提出了节省能量的路由策略以有效延长网络生存时间;对于水下三维立体形式提出一种不依赖位置信息的路由机制,并针对数据转发中存在的路由空洞设计了有效的路由重构机制。     

风云三号D星真彩色影像合成方法研究及应用

多光谱遥感数据真彩色合成影像具有处理速度快、不依赖其他遥感产品、易于理解判读等特点,其在气象、生态环境、减灾等领域具有不可替代的作用。本文以风云三号D卫星MERSI-Ⅱ传感器数据为例,经过大气校正和非线性拉伸等方法合成了真彩色影像。应用真彩色影像对沙尘、蓝藻、火灾和台风等事件进行监测分析,分析结果表明真彩色影像可以在上述事件中起到识别相关事件的影响范围、事件的发展变化情况等信息的作用。     

基于弹性网回归的水下目标无监督特征选择算法

针对水声数据的特征中含有大量冗余、不相关和噪声特征,导致水声目标识别正确率降低的问题,提出了一种新的水下目标特征选择方法——基于弹性网回归的无监督特征选择算法(Unsupervised fea- ture selection algorithm based on elastic-net regression,UFSER)。 该算法利用谱回归得到高维水声数据和其低维表示之间的回归系数矩阵,并且在回归框架中加入弹性网惩罚项优化求解回归系数矩阵;最后,对回归系数矩阵进行稀疏化从而对特征的分类性能进行评价。 使用实测水声数据集和 UCI 声呐数据集进行特征选择和 SVM 分类实验。 实验结果表明：在特征数目分别减少 60.6%和 60%的情况下,分类识别正确率较特征选择前提升了 1.05%和 6.6%。     

无线传感器网络中一种增强DV-Hop算法

无线传感器网络中的DV-Hop算法是1种无需测距的节点定位算法。经仿真观察,该算法存在类似“块效应“的定位误差。文中作者提出1种增强DV-Hop算法,通过锚节点的定位结果,对未知节点的定位结果进行修正。经仿真验证,增强算法可以有效解决“块效应“,提高算法的定位精度与鲁棒性。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.