Abstract Ship noise analysis is a critical area of research in hydroacoustic remote sensing due to its practical implications in identifying ship direction, type, and even specific ship identities. However, the limited availability of data poses challenges in developing accurate ship noise classification models. Previous studies have mainly focused on small-sample learning approaches, resulting in complex network structures. Nonetheless, underwater robots often have limited computing power, making it essential to develop simpler recognition networks. In this paper, we address the issue of data scarcity by introducing positive incentive noise. We propose a CNN-based hydroacoustic signal recognition method that achieves comparable or superior performance to previous studies, using a simple network structure as a back-end decision system. We describe the feature extraction process using a dataset with added noise and compare the performance of various features. Additionally, we compare our proposed method with previous studies. Experimental results demonstrate that simple neural networks can achieve high performance and excellent generalizability without the need for complex network structures like adversarial learning models.
This paper is concerned with the path planning of the coal mine robot. A new workspace model is presented to describe the complex coal mine environment. Thus, the cost of a path is composed of not only the distance of the path but also some hybrid costs that can be linked to the criteria of path optimization. To overcome the drawbacks of conventional ant colony optimization (ACO) algorithm, an improved ACO algorithm is developed to tackle the issues of path planning of coal mine robot based on the new workspace model. Some simulation experiments are carried out on the path planning of coal mine robot, and the validity and superiority of the new approach can be confirmed by the simulation results.
The structure of leather material was analyzed by fourier transform attenuated total reflection infrared spectroscopy(ATR-FTIR),which can be used to distinguish real leather and artificial leather quickly according to different ATR spectrums without destroying samples.
In this paper, a kind of theoretical method of how to find out the dominant cladding modes in the all in-fiber interferometer is proposed. The relationship between the cladding modes spatial frequency and its modal order and sensing optical fiber length are simulated. It can be found that the fiber length increasing can make the value of the dominant cladding spatial frequency linearly increase. The order of the dominant cladding modes are increasing with fiber length. With the sensing optical fiber length increasing, some higher order cladding modes are excited and participate in the interference spectrum of the interferometer, which makes the fringe spacing of the interference spectrum finer.
The location of welding initial position is the main problem to realize automatic welding in the process of container reinforced plate welding. According to the characteristic of container reinforced plate, the location system for reinforced plate welding is designed, which is based on the structured light. This system consists of two lasers and one camera, which is easier for image processing with its obvious characteristics of structured-light in welding environment. Welding robot can be guided to the initial welding position of any planar weld automatically by the structured-light visual system. Structured-light center stripes and their endpoints are obtained by gray morphology and scanning column pixels of binary image. Then initial welding position is located by theory between points and lines. Using the superiority of structured light, this system solves the problem of reinforced plate localization, avoiding the drawbacks of instability, image processing which is high time-consuming and low precision.
This paper investigates the real-time customized bus (CB) route optimization problem, which aims to maximize the service rate for clients and profits for operators. The on-road bus has a flexible route, which can be updated based on the real-time data and route optimization solutions. A two-phase framework is established. In phase 1, the vehicle-related data including existing route and schedule, client-related data involving pick-up/drop-off location, and time windows are collected once receiving a new CB request. The second phase optimizes the bus route by establishing three nonlinear programming models under the given data from phase 1. A concept of profit difference is introduced to decide the served demand. To improve computation efficiency, a real-time search algorithm is proposed that the neighboring buses are tested one by one. Finally, a numerical study based on Sioux Falls network reveals the effectiveness of the proposed methodology. The results indicate that the real-time route optimization can be achieved within the computation time of 0.17–0.38 seconds.
To handle the fault diagnosis of multilevel inverter, a new approach based on hybrid intelligent algorithms has been proposed in this paper. Firstly, the wavelet packet transform (WPT) is applied for the multi-scale wavelet packet decomposition of the fault signal, and the fault feature vector is extracted from the reconstructed wavelet packet energy. Then, the principal component analysis (PCA) is employed to extract the principal information with lower dimension. Finally, the BP neural network (NN) is used for the fault diagnosis and identification. The simulation results show that the proposed method is more accurate for the fault diagnosis of multilevel inverter than traditional methods and more robust to the noise of fault signals.
In this paper, ZrO(OH)2 was prepared with sol-gel method, then a series of metal-ions-doped SO(2)4- /ZrO2 nanosolid superacids were prepared by impregnated ZrO(OH)2 using diluted H2SO4 and Ni2+ , Al3+, Sn4+, Ag+ , Sn2+ etc. salt solutions. The samples were characterized by IR, XRD, TEM and chemical analysis method. The result shows that the IR spectra of samples are the characteristic spectra of the solid superacids. The stretching frequencies of Zr--O and S==O in Ni2+ and Sn4+ doped samples are obviously increased, the v(Zr-o) values of Zr--O increase from 485 cm(-1) for SO(2)4- /ZrO2 to 500 cm(-1) for both Ni2+ and Sn4+ doped samples, the v(as) values of S==O increase from 1 390 cm(-1) for So(2)4- /ZrO2 to 1405 and 1400 cm(-1) for Ni2+ and Sn4+ doped samples respectively, but that in Sn2+ doped sample increases a little. It is indicated that the samples doped by Ni2+ and Sn4+ show higher super acidity than SO(2)4- /ZrO2 . The IR spectra of samples were determined at different calcination temperatures. It was found that the stretching frequencies of Zr--O and S==O in Ni2+ and Al3+ doped samples are obviously increased with the increase in calcination temperature, but that in Ag+ doped sample is not.
This paper is concerned with the open-circuit fault diagnosis of MMC sub-module. To estimate the arm current accurately in normal and fault cases, a sliding mode observer is designed based on Lyapunov theory. The residual between the estimation and measurement of the arm current will increase rapidly in fault cases, which can facilitate not only the open-circuit fault detection of the arm but also the identification of the fault type. Based on the open-circuit fault analysis of MMC sub-module, the fault feature is defined and calculated for the fault location of sub-module, which can remarkably promote the efficiency of fault diagnosis. To test the performance of the proposed approach, some simulation experiments are carried out and can confirm the effectiveness of the proposed approach for the open-circuit fault diagnosis of MMC sub-module.
The structure characteristics and function of IDT7026,a dual port RAM chip,are introduced,which has been applied to the low-frequency time-code signal acquisition system so as to realize the data transfer and sharing between DSP(Digital Signal Processor)and single chip.A practical interface circuit used for communication between DSP and single chip via IDT7026 is presented.Two ways,i.e.token transfer and software arbitration are brought forward to realize the arbitration mode for data exchange in low-frequeney time-code signal acquisition system.
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