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<title cf:type="text"><![CDATA[Editorial department of the Journal of National University of Defense Technology -->机械工程·计算机科学与技术]]></title>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Research progress of energy and actuation technology for micro-soft robots]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303009]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Micro-soft robots with high compliance, low energy consumption and high energy density have wide application prospects in complex environments such as pipeline maintenance and battle field reconnaissance. Energy and actuator play a decisive role in the motion modes and performances of micro-soft robots. In order to make more researchers understand the research progresses of the existing flexible driving technology and their energy sources, the typical driving methods based on physical energy driving, chemical energy driving and biological hybrid driving were summarized and analyzed. The shortcomings and future development of the existing flexible driving technology and their energy sources were discussed and summarized, which can provide reference for the development and improving performance of the flexible drive technology of soft robots in the future.]]></description>
<pubDate>2023/6/7 0:00:00</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[YANG Yun, LIN Zening, HONG Yang, JIANG Tao, SHANG Jianzhong, LUO Zirong]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YANG Yun, LIN Zening, HONG Yang, JIANG Tao, SHANG Jianzhong, LUO Zirong</atom:name>
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<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303009]]></guid><cfi:id>8</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Line spectrum unsteady thrust prediction method and test verification of pump jet]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303010]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to predict the unsteady thrust of the interaction line spectrum of the pump jet propeller rotor and the periodic leading vane wake, ignored the thickness of the pump jet propeller rotor blades, and simplified the pump jet rotor into an annular cascade. According to the sheet theory, the radius that is the segment of the pump jet rotor was intercepted at <i>r</i>, and the change of the flow field parameters along the segment radial was ignored. Therefore, the annular cascade segment can be considered as a planar cascade, and the periodic inflow is considered based on the interaction between the planar cascade and the harmonic wave. The unsteady excitation force of the interaction line spectrum between the front guide vane segment and the rotor segment is derived. The unsteady thrust line spectrum prediction formula is obtained through the circumferential integration of the rotor segment. The validity of the formula is verified through numerical and experimental methods. A design parameter impact analysis was conducted, and it was found that when the ratio of the current guide vane rotor spacing to the chord length of the front guide vane is greater than 1, the rotor rear guide vane spacing has almost no impact on the excitation force line spectrum thrust of a single rotor blade.]]></description>
<pubDate>2023/6/7 9:08:55</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[HE Shengyang, WU Xingyu, WEI Yingsan, JIN Shuanbao, ZHAI Shuo, CHENG Gong]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>HE Shengyang, WU Xingyu, WEI Yingsan, JIN Shuanbao, ZHAI Shuo, CHENG Gong</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303010]]></guid><cfi:id>7</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Influence of third order harmonic of air gap flux density on motor vibration and noise]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303011]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Aiming at the problem of electromagnetic vibration and noise of motor, it was found that improving the sinusoidal characteristic of air gap flux density does not necessarily reduce the vibration and noise of motor. In view of this, the order and frequency of the main force wave causing the vibration and noise of the motor were analyzed, and the specific functional relationship between the third order harmonic of air gap flux density and the vibration and noise of the motor was explored. In order to analyze the order and frequency of the main force wave which caused the vibration and noise of the motor, the force wave table was eliminated based on the analytical method, and the main noise source was determined. In order to explore the influence of the third order harmonic of air gap flux density on motor vibration and noise, the mathematical models of air gap flux density and radial force wave were established, and the optimal amplitude of the third order harmonic of air gap flux density was solved by genetic algorithm. The analysis results show that improving the sinusoidal air gap flux density does not necessarily reduce the vibration noise of the motor, and the third order harmonic of air gap flux density has an optimal value in a certain range to minimize the vibration noise of the motor. The analysis results provide a reference for the design of low noise motor.]]></description>
<pubDate>2023/6/7 9:08:55</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[QIAO Mingzhong, LU Xihao, ZHANG Chi]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>QIAO Mingzhong, LU Xihao, ZHANG Chi</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303011]]></guid><cfi:id>6</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Motor bearing fault diagnosis by combining vibration feature optimization and GWOA-XGBoost]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303012]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to solve the problem that the fault state of motor bearings is difficult to identify, which results in low diagnosis accuracy, a motor bearing fault diagnosis model was proposed by combining the signal feature extraction and XGBoost (extreme gradient boosting algorithm). The optimized variational mode decomposition was used to obtain the IMF(intrinsic mode function) components of the vibration signal, and the multi scale entropy value of each IMF component was calculated on the basis of the multi-scale entropy theory for feature reconstruction. The WOA (whale optimization algorithm) was improved by introducing the selection, crossover and mutation operation of genetic algorithm. The improved WOA algorithm was used to optimize the hyperparameters of XGBoost, and obtain the hyperparameter combination that helped the XGBoost achieve the best classification effect. The vibration signals of 7 different types of faults were reconstructed and input into the optimized XGBoost model for fault diagnosis. Experimental results show that the motor bearing fault diagnosis accuracy of the proposed GWOA-XGBoost model can reach 97.14%, which significantly improves the performance compared with the traditional diagnosis method.]]></description>
<pubDate>2023/6/7 9:08:55</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[YU Fei, FAN Qingchuan, XUAN Min]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YU Fei, FAN Qingchuan, XUAN Min</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303012]]></guid><cfi:id>5</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Research and verification of numerical calculation method for submarine′s buoyancy motion]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303013]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Predicting submarine buoyancy motion is a prerequisite for exploring and studying the laws of submarine buoyancy motion control and submarine buoyancy safety. The numerical calculation method and calculation process of submarine buoyancy motion were introduced in detail. The turbulence model and discrete scheme in the numerical calculation method were optimized. The uncertainty of numerical calculation was analyzed and the results of numerical calculation were verified based on the model floating test′s results, what′s more, it was found that the reliability of numerical calculation was proved and the numerical calculation results were in good agreement with the experimental results, thus verifying the feasibility of the numerical calculation method. The numerical calculation method and test can provide reference and reference for the research of submarine floating movement.]]></description>
<pubDate>2023/6/7 9:08:55</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[WEI Keke, GAO Xiaopeng, MA Cheng, DONG Zushun]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WEI Keke, GAO Xiaopeng, MA Cheng, DONG Zushun</atom:name>
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<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303013]]></guid><cfi:id>4</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Model agnostic federated mutual learning]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303014]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The mainstream FL(federated learning) methods require gradient interaction and the ideal assumption of the independently identically distribution, which brings additional communication overhead, privacy leakage, and data inefficiency. Therefore, a new FL framework called MAFML (model agnostic federated mutual learning) was proposed. MAFML only used a small amount of low-dimensional information (for example, the soft labels output of the neural network in the image classification task) for sharing to achieve cross-participants “mutual learning and mutual education”. Moreover, MAFML did not need a shared global model, users can customize their own private models without restricting the model structure and parameters. At the same time, MAFML used a general approach for avoiding gradient interference so that each participant′s model could be well generalized to other domains without reducing the performance of its own domain data. Experiments on multiple cross-domain datasets show that MAFML can provide a promising solution for alliance business facing the “competition and cooperation” dilemma.]]></description>
<pubDate>2023/6/7 9:08:55</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[ZHOU Wei, LI Yiying, CHEN Shuhui, DIND Bo]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHOU Wei, LI Yiying, CHEN Shuhui, DIND Bo</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303014]]></guid><cfi:id>3</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Algorithm on image restoration of parallel generation convolution network]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303015]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to solve the defects of edge artifacts and semantic discontinuity when inpainting large and irregular distortions in an image with fine texture and complex background, a residual connection image restoration algorithm based on parallel generation convolution was proposed. The damaged image was inputted into a two-column parallel convolutional structure inpainting network to obtain two image components with different sizes of reception fields. The two image components were combined by the shared decoding and the L2 loss of the output was calculated to optimize the network. The output of the coarse network was sent into the fine inpainting network which contained the residual connection and the attention mechanism to fuse context information and improve the ability of repairing fine details. The global and local discriminators and visual geometry group net were used to calculate the loss and to optimize the overall discrimination network and enhance the global and local consistency of the inpainting result. The performance of the proposed algorithm was validated on internationally recognized databases, and experimental results show that the proposed algorithm can effectively repair large and irregular missing areas under complex background and fine texture, improve the authenticity and integrity of image details, semantics and structure. Its peak signal-to-noise ratio and structural similarity are superior to the state-of-the-art.]]></description>
<pubDate>2023/6/7 9:08:56</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[LI Haiyan, CHAO Yanjing, LI Haijiang, GUO Lei, LI Hongsong]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LI Haiyan, CHAO Yanjing, LI Haijiang, GUO Lei, LI Hongsong</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303015]]></guid><cfi:id>2</cfi:id><cfi:read>true</cfi:read></item>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Video behavior recognition network using multi time-scale convolution]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303016]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The behavior recognition network based on 2D convolutional usually integrates classification results of multiple video frames to recognize different behaviors, but it can′t extract space-time feature using the 2D convolution kernels. To solve this problem, MTSC (multi time-scale convolution) was proposed based on TSM(temporal shift module), which contained convolution kernels of different scales to fuse the space-time feature from different time scales. By controlling the position that inserting MTSC into ResNet50 network and the parameter setting of MTSC, the optimal behavior recognition network based on MTSC was discussed. Using the PyTorch training model, an experimental study was conducted on a large open source dataset, Something-Something v2. The results show that the behavior recognition network based on MTSC achieves 59.47% Top-1 accuracy, and outperform TSM and other behavior recognition networks.]]></description>
<pubDate>2023/6/7 9:08:56</pubDate>
<category><![CDATA[机械工程·计算机科学与技术]]></category>
<author><![CDATA[CHEN Xijiang, LIANG Quanen, HAN Xianquan, AN Qing]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>CHEN Xijiang, LIANG Quanen, HAN Xianquan, AN Qing</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202303016]]></guid><cfi:id>1</cfi:id><cfi:read>true</cfi:read></item>
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