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Aslotted floor acquisitionmultiple access based MACprotocol for underwater acoustic networks withRTS

Liang-fang QIAN,Sen-lin ZHANG,Mei-qin LIU

《信息与电子工程前沿（英文）》 2015年第16卷第3期页码 217-226 doi: 10.1631/FITEE.1400187

摘要： Long propagation delay, limited bandwidth, and high bit error rate pose great challenges in media access control (MAC) protocol design for underwater acoustic networks. A MAC protocol called slotted floor acquisition multiple access (slotted-FAMA) suitable for underwater acoustic networks is proposed and analyzed. This FAMA based protocol adds a time slot mechanism to avoid DATA packet collisions. However, slotted-FAMA is not suitable for dense networks since the multiple request-to-send (RTS) attempts problem in dense networks is serious and greatly limits the network throughput. To overcome this drawback, this paper proposes a slotted-FAMA based MAC protocol for underwater acoustic networks, called RC-SFAMA. RC-SFAMA introduces an RTS competition mechanism to keep the network from high frequency of backoff caused by the multiple RTS attempts problem. Via the RTS competition mechanism, useful data transmission can be completed successfully when the situation of multiple RTS attempts occurs. Simulation results show that RC-SFAMA increases the network throughput efficiency as compared with slotted-FAMA, and minimizes the energy consumption.

关键词： Underwater acoustic networks Medium access control (MAC) Request-to-send (RTS) competition Throughput Energy consumption

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基于改进Merkle哈希树的仿生水声通信安全方案 Research Articles

Masoud KAVEH,Abolfazl FALAHATI

《信息与电子工程前沿（英文）》 2021年第22卷第7期页码 1010-1019 doi: 10.1631/FITEE.2000043

摘要：近来，在传输系统中仿生信号已用于实现具有高信噪比的隐蔽水声通信。高信噪比使得攻击者能实行恶意计划，导致传输系统易受恶意攻击。提出一种基于改进Merkle哈希树的安全方案，能够抵御当前水下攻击，具体包含重放攻击、伪造消息攻击、消息篡改攻击和分析攻击。进行安全性分析，证明所提方案能够抵抗这些类型的攻击。性能评估表明，该方案在能量消耗、通信开销和计算开销方面的效率可满足水声通信的限制要求。

关键词：海豚哨音；改进Merkle哈希树；安全水声通信（UWAC）

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基于到达时间差和到达频率差的多层等梯度声速剖面建模与声学定位 Research Article

詹东洲1,王思甜1,蔡守桂1,郑华荣2,徐文2

《信息与电子工程前沿（英文）》 2023年第24卷第1期页码 164-175 doi: 10.1631/FITEE.2100398

摘要：在水下媒介中，声速随着水深、温度和盐度而变化。水体的不均匀性导致声线弯折，使得现有基于声信号直线传播假设的定位算法不够精确。为实现水下声学传感网络中的高精度节点定位，本文首先使用线性分割近似方法，提出多层等梯度声速剖面（sound speed profile，SSP）模型。基于此模型，可将声线跟踪问题转化为多项式寻根问题。利用传感器节点处信号多普勒频移的导数，提出一种新的使用到达时间差（time difference of arrival，TDOA）和到达频率差（frequency difference of arrival，FDOA）的水下节点定位算法。通过模拟仿真，可以证明所提算法的有效性。与传统基于直线传播假设的方法相比，所提算法可有效处理声线弯折现象。此外，研究了不同SSP建模误差下的估计精度。总体而言，新提出的方法可以实现准确可靠的节点定位。

关键词：水下声学传感器网络；声学定位；声速剖面；到达时间差（TDOA）；到达频率差（FDOA）

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基于互信息的水下无线传感器网络目标跟踪与加权融合 None

Duo ZHANG, Mei-qin LIU, Sen-lin ZHANG, Zhen FAN, Qun-fei ZHANG

《信息与电子工程前沿（英文）》 2018年第19卷第4期页码 544-556 doi: 10.1631/FITEE.1601695

摘要：水下无线传感器网络为水下目标跟踪问题提供了可靠有效支持，但水下网络能量和带宽资源有限，只能选择一部分节点参与跟踪任务。融合中心通过收集、融合各个传感器发送的量测进行目标跟踪，因此设计更好的融合权值极为重要。针对水下目标跟踪中的加权融合问题，首先通过计算量测与目标状态之间的互信息，利用互信息衡量融合权重；其次利用互信息融合权重设计一种新的多传感器加权粒子滤波算法，利用克拉美罗（Cramer-Rao）下界设计节点选择方案，以提高跟踪算法效率；最后通过仿真实验对算法进行验证。仿真结果表明，通过选择合适融合权值，目标状态估计精度显著提高。

关键词：目标跟踪；加权融合；互信息；节点选择；水下无线传感器网络

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水下移动传感器网络的高能效节点定位和目标跟踪 None

Hua-yan CHEN, Mei-qin LIU, Sen-lin ZHANG

《信息与电子工程前沿（英文）》 2018年第19卷第8期页码 999-1012 doi: 10.1631/FITEE.1700598

摘要：水下移动传感器网络（UMSNs）不要固定，易实现快速部署，其节点可随洋流飘动扩散，易实现大范围的监测。因此，UMSNs是远海环境下实现短期、迅速、大范围组网监测跟踪的有效手段。UMSNs目标跟踪的挑战在于高精度的目标跟踪效果需要以高精度的实时节点定位为前提，而UMSNs的节点位置是不断变化的。为获得高精度的实时节点定位结果，运用传统的定位方案对其进行连续定位将会消耗大量能量。为减少UMSNs目标跟踪过程中节点定位所消耗能量，利用节点移动在时间空间的相关性，结合多步Levinson-Durbin线性预测算法提出高精度的长周期节点位置预测算法（HLMP）。通过高精度位置预测减少节点对实时通信定位的依赖，进而减少网络能耗。根据目标跟踪过程中节点与目标的相关性，提出同时定位跟踪算法（SLAT），进一步提高节点的定位精度。仿真结果表明，HLMP算法能够在低能耗的情况下显着提高定位精度，SLAT算法进一步降低节点定位误差。更高的定位精度将同步提高目标跟踪性能。

关键词：水下移动传感器网络；高能效；节点定位；目标跟踪

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Augmentation of natural convective heat transfer by acoustic cavitation

Jun CAI, Xiulan HUAI, Shiqiang LIANG, Xunfeng LI,

《能源前沿（英文）》 2010年第4卷第3期页码 313-318 doi: 10.1007/s11708-009-0064-3

摘要： An experimental study was conducted to investigate the effects of acoustic cavitation on natural convective heat transfer from a horizontal circular tube. The experimental results indicated that heat transfer could be enhanced by acoustic cavitation and had the best effect when the head of the ultrasonic transducer was over the midpoint of the circular tube, and the distance between the head and the tube equaled 15 mm. The augmentation at low heat flux was better than that in the case of high heat flux. Based on experimental results, the correlation formula of Nusselt number for water was obtained.

关键词： heat transfer enhancement augmentation acoustic cavitation acoustic streaming convective heat transfer

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IEEE SENSORS 2019

会议日期： 2019年10月27日

会议地点：加拿大/蒙特利尔

主办单位： Institute of Electrical and Electronics Engineers

Acoustic fault signal extraction via the line-defect phononic crystals

《机械工程前沿（英文）》 2022年第17卷第1期页码 10-10 doi: 10.1007/s11465-021-0666-y

摘要： Rotating machine fault signal extraction becomes increasingly important in practical engineering applications. However, fault signals with low signal-to-noise ratios (SNRs) are difficult to extract, especially at the early stage of fault diagnosis. In this paper, 2D line-defect phononic crystals (PCs) consisting of periodic acrylic tubes with slit are proposed for weak signal detection. The defect band, namely, the formed resonance band of line-defect PCs enables the incident acoustic wave at the resonance frequency to be trapped and enhanced at the resonance cavity. The noise can be filtered by the band gap. As a result, fault signals with high SNRs can be obtained for fault feature extraction. The effectiveness of weak harmonic and periodic impulse signal detection via line-defect PCs are investigated in numerical and experimental studies. All the numerical and experimental results indicate that line-defect PCs can be well used for extracting weak harmonic and periodic impulse signals. This work will provide potential for extracting weak signals in many practical engineering applications.

关键词： phononic crystals line-defect fault signal extraction acoustic enhancement

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Turbidity-adaptive underwater image enhancement method using image fusion

《机械工程前沿（英文）》 2022年第17卷第3期 doi: 10.1007/s11465-021-0669-8

摘要： Clear, correct imaging is a prerequisite for underwater operations. In real freshwater environment including rivers and lakes, the water bodies are usually turbid and dynamic, which brings extra troubles to quality of imaging due to color deviation and suspended particulate. Most of the existing underwater imaging methods focus on relatively clear underwater environment, it is uncertain that if those methods can work well in turbid and dynamic underwater environments. In this paper, we propose a turbidity-adaptive underwater image enhancement method. To deal with attenuation and scattering of varying degree, the turbidity is detected by the histogram of images. Based on the detection result, different image enhancement strategies are designed to deal with the problem of color deviation and blurring. The proposed method is verified by an underwater image dataset captured in real underwater environment. The result is evaluated by image metrics including structure similarity index measure, underwater color image quality evaluation metric, and speeded-up robust features. Test results exhibit that the method can correct the color deviation and improve the quality of underwater images.

关键词： turbidity underwater image enhancement image fusion underwater robots visibility

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Experimental study on wire breakage detection by acoustic emission

Limin SUN, Ji QIAN

《结构与土木工程前沿（英文）》 2011年第5卷第4期页码 503-509 doi: 10.1007/s11709-011-0132-8

摘要： This paper experimentally investigated wire breakage detection in a steel cable by acoustic emission (AE) waveform. In the experiments, the attenuation laws of waveform amplitudes were discussed based on stress wave propagation in the wire, which was generated by kNocking and wire breakage. Then the wave velocity was calculated based on the reach time of the stress wave from each sensor. Finally, based on the waveform attenuation laws and the linear position method, the amplitude and energy of the source were confirmed through the measured waveform to identify the source category. The experimental results illustrated that the stress wave from different sources has a different frequency spectrum, and the amplitude attenuation factor varied with the stress wave frequency; high frequency waves had a greater attenuation factor. Compared with the other source, the wire breakage source contained a much higher energy, and thus, the wire breakage signal can be distinguished from the other source by comparing the non-attenuation energy at the source position.

关键词： acoustic emission (AE) waveform wire breakage attenuation factor wave velocity

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Simulation and experimental improvement on a small-scale Stirling thermo-acoustic engine

Mao CHEN,Yonglin JU

《能源前沿（英文）》 2016年第10卷第1期页码 37-45 doi: 10.1007/s11708-015-0390-6

摘要： Compared with the traditional engines, the thermo-acoustic engines are relatively new and can act as the linear compressors for refrigerators. Many institutes have shown great interest in this kind of machine for its absence of moving mechanical part. In this paper, the influence of the dimensions of the main parts of the small-scale Stirling thermo-acoustic engine was numerically simulated using a computer code called DeltaEC. The resonator and the resonator cavity were found to be the most convenient and effective in improving the performance of the engine. Based on the numerical simulation, a small-scale Stirling thermo-acoustic engine were constructed and experimentally investigated. Currently, with a resonator length of only 1 m, the working frequency of the engine was decreased to 90 Hz and the onset temperature difference was decreased to 198.2 K.

关键词： thermo-acoustic Stirling engine small-scale simulation experiment

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Acoustic characteristics of bi-directional turbines for thermoacoustic generators

Dongdong LIU, Yanyan CHEN, Wei DAI, Ercang LUO

《能源前沿（英文）》 2022年第16卷第6期页码 1027-1036 doi: 10.1007/s11708-020-0702-3

摘要： Bi-directional turbines combined with rotary motors may be a feasible option for developing high power thermoacoustic generators with low cost. A general expression for the acoustic characteristics of the bi-directional turbine was proposed based on theoretical derivation, which was validated by computational fluid dynamics modeling of an impulse turbine with fixed guide vanes. The structure of the turbine was optimized primarily using steady flow with an efficiency of near 70% (the shaft power divided by the total energy consumed by the turbine). The turbine in the oscillating flow was treated in a lumped-parameter model to extract the acoustic impedance characteristics from the simulation results. The key acoustic impedance characteristic of the turbine was the resistance and inertance due to complex flow condition in the turbine, whereas the capacitance was treated as an adiabatic case because of the large-scale flow channel relative to the heat penetration depth. Correlations for the impedance were obtained from both theoretical predictions and numerical fittings. The good fit of the correlations shows that these characteristics are valid for describing the bi-directional turbine, providing the basis for optimization of the coupling between the thermoacoustic engine and the turbine using quasi-one-dimensional theory in the frequency domain.

关键词： thermoacoustic power generator acoustic characteristics bi-directional impulse turbine energy conversion

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Research on acoustic-structure sensitivity using FEM and BEM

ZHANG Jun, ZHAO Wenzhong, ZHANG Weiying

《机械工程前沿（英文）》 2007年第2卷第1期页码 62-67 doi: 10.1007/s11465-007-0010-1

摘要： Acoustic-structure sensitivity is used to predict the change of acoustic pressure when a structure design variable is changed. The sensitivity is significant for reducing noise of structure. Using FEM (finite element method) and BEM (boundary element method) acoustic-structure sensitivity was formulated and presented. The dynamic response and response velocity sensitivity with respect to structure design variable were carried out by using structural FEM, the acoustic response and acoustic pressure sensitivity with respect to structure velocity were carried out by using acoustic BEM. Then, acoustic-structure sensitivity was computed by linking velocity sensitivity in FEM and acoustic sensitivity in BEM. This method was applied to an empty box as an example. Acoustic pressure sensitivity with respect to structure thickness achieved in frequency ranges 1 100 Hz, and its change rule along with stimulating frequency and design variable were analyzed. Results show that acoustic-structure sensitivity method linked with FEM and BEM is effective and correct.

关键词： sensitivity method BEM acoustic pressure pressure sensitivity frequency

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Acoustic emissions evaluation of the dynamic splitting tensile properties of steel fiber reinforced concrete

《结构与土木工程前沿（英文）》页码 1341-1356 doi: 10.1007/s11709-023-0988-4

摘要： This study empirically investigated the influence of freeze–thaw cycling on the dynamic splitting tensile properties of steel fiber reinforced concrete (SFRC). Brazilian disc splitting tests were conducted using four loading rates (0.002, 0.02, 0.2, and 2 mm/s) on specimens with four steel fiber contents (0%, 0.6%, 1.2%, and 1.8%) subjected to 0 and 50 freeze–thaw cycles. The dynamic splitting tensile damage characteristics were evaluated using acoustic emission (AE) parameter analysis and Fourier transform spectral analysis. The results quantified using the freeze–thaw damage factor defined in this paper indicate that the degree of damage to SFRC caused by freeze–thaw cycling was aggravated with increasing loading rate but mitigated by increasing fiber content. The percentage of low-frequency AE signals produced by the SFRC specimens during loading decreased with increasing loading rate, whereas that of high-frequency AE signals increased. Freeze–thaw action had little effect on the crack types observed during the early and middle stages of the loading process; however, the primary crack type observed during the later stage of loading changed from shear to tensile after the SFRC specimens were subjected to freeze–thaw cycling. Notably, the results of this study indicate that the freeze–thaw damage to SFRC reduces AE signal activity at low frequencies.

关键词： steel fiber reinforced concrete freeze–thaw cycling Brazilian disc splitting test acoustic emission technique dynamic splitting tensile acoustic emission properties

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一种用于寻找无人船回收海床基数据最佳通信点的梯度上升控制法 Research Papers

Jiu-cai JIN, Jie ZHANG, Zhi-chao LV

《信息与电子工程前沿（英文）》 2019年第20卷第6期页码 751-759 doi: 10.1631/FITEE.1700732

摘要：给出了一种在无人船声学回收海床基数据时寻找最佳通信点的控制方法。众所周知，梯度上升极值寻找法常应用于多平台或多智能体，这是因为多平台能大范围测量且易于梯度估计。单一平台测量范围有限，不能快速估计测量场，难以迅速获得测量场极值。本文提出一种无人船振荡运动形式，以获取海床基与无人船间水声通信链路强度数据。基于多元加权线性递归法，利用无人船振荡运动获取的新数据，不断更新水声通信链路强度场。基于梯度上升和人工势场方法，考虑未知场的递归估计，设计无人船最佳通信点控制器，并证明其稳定性。仿真结果表明该算法可靠、高效。

关键词：无人船；数据回收；水声通信；梯度上升；极值寻找

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标题作者时间类型操作

Aslotted floor acquisitionmultiple access based MACprotocol for underwater acoustic networks withRTS

Liang-fang QIAN,Sen-lin ZHANG,Mei-qin LIU

期刊论文

基于改进Merkle哈希树的仿生水声通信安全方案

Masoud KAVEH,Abolfazl FALAHATI

期刊论文

基于到达时间差和到达频率差的多层等梯度声速剖面建模与声学定位

詹东洲1,王思甜1,蔡守桂1,郑华荣2,徐文2

期刊论文