检索结果-南通市图书馆

融合语义分割与模糊推理的无人机应急降落选址算法

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

计算机工程与应用 2025年第1期61卷 174-185页

作者：李迪肖敏任东谢咏昶姚远三峡大学计算机与信息学院湖北宜昌443002 三峡大学湖北省农田环境监测工程技术研究中心湖北宜昌443002

随着无人机的应用领域从娱乐摄影拓展到物流、军事和灾害响应,对于无人机的自主智能化要求也越来越高。针对无人机紧急情况下自主降落区域复杂难以保证着陆安全的问题,提出了一种实时语义分割网络与模糊推理相结合的降落选址算法(STDC-L... 详细信息

随着无人机的应用领域从娱乐摄影拓展到物流、军事和灾害响应,对于无人机的自主智能化要求也越来越高。针对无人机紧急情况下自主降落区域复杂难以保证着陆安全的问题,提出了一种实时语义分割网络与模糊推理相结合的降落选址算法(STDC-LSSNet)。考虑到潜在危险因素在航拍图像上占比小、易被错误分割的问题,提出了小目标特征提取模块(small target feature capture module,STFCM),通过计算不同尺度特征的相似性并进行权重分配,强化小目标特征的表达。考虑到安全区域与危险区域边界混淆会导致无人机降落存在巨大风险,提出了边界特征融合模块(boundary feature fusion module,BFFM),将浅层网络由拉普拉斯卷积得到的边界信息与深层网络的语义信息进行特征融合,引入注意力机制,增强边界区域特征的表达。通过对分割得到的图像进行模糊推理,从而精确识别应急降落地点。所提算法在公开数据集Semantic Drone和AeroScapes上与最先进的算法进行了广泛的对比实验,mIoU提升1.72个百分点和3.89个百分点,实时分割速度达到210 FPS,选址的速度达到58.62 ms,实现了无人机在复杂情况下的应急降落选址。

关键词：无人机自主降落实时语义分割模糊推理注意力机制

linear Optimal Estimation of Discrete-time Systems with Multiple Measurement Delays 36

在线全文

学校读者我要写书评

暂无评论

Linear Optimal Estimation of Discrete-time Systems with Mult...

A survey on multi-agent reinforcement learning and its application

第36届中国控制会议

作者： Shuai liu lihua xie School of Control Science and Engineering Shandong University School of Electrical and Electronic Engineering Nanyang Technological University

ISBN: (纸本)9781538629185

In this paper, we consider an optimal estimation problem in the sense of least mean square error for linear discrete-time systems with multiple state delays in the measurement output. Since computation complexity is high for augmentation approach,a lot of researches have been dedicated to finding alternative ways for the optimal estimation design. In existing studies, two dimensional Riccati iteration is unavoidable for calculating the optimal gain. Meanwhile, in the continuous-time setting, the counterpart of the two dimensional Riccati equation is partial differential equation which is difficult to solve. We shall provide a new result that the gain of the optimal estimation is obtained in terms of the solution of a Retarded Riccati-like equation instead of two dimensional Riccati equation. Furthermore, by applying the result to single delay case, we have found a relationship between optimal estimation of systems with multiple delays and optimal prediction.

关键词： Riccati Equation Delay Systems Optimal Estimation

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Automation and Intelligence 2024年第2期3卷 73-91页

作者： Zepeng Ning lihua xie School of Electrical and Electronic Engineering Nanyang Technological UniversityNanyang Avenue639798Singapore

Multi-agent reinforcement learning(MARL)has been a rapidly evolving *** paper presents a comprehensive survey of MARL and its *** trace the historical evolution of MARL,highlight its progress,and discuss related survey ***,we review the existing works addressing inherent challenges and those focusing on diverse *** representative stochastic games,MARL means,spatial forms of MARL,and task classification are *** then conduct an in-depth exploration of a variety of challenges encountered in MARL *** also address critical operational aspects,such as hyperparameter tuning and computational complexity,which are pivotal in practical implementations of ***,we make a thorough overview of the applications of MARL to intelligent machines and devices,chemical engineering,biotechnology,healthcare,and societal issues,which highlights the extensive potential and relevance of MARL within both current and future technological *** survey also encompasses a detailed examination of benchmark environments used in MARL research,which are instrumental in evaluating MARL algorithms and demonstrate the adaptability of MARL to diverse application *** the end,we give our prospect for MARL and discuss their related techniques and potential future applications.

关键词： Benchmark environments Multi-agent reinforcement learning Multi-agent systems Stochastic games

Marginal Attacks of Generating Adversarial Examples for Spam Filtering

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2021年第4期30卷 595-602页

作者： GU Zhaoquan xie Yushun HU Weixiong YIN lihua HAN Yi TIAN Zhihong Cyberspace Institute of Advanced Technology Guangzhou University

Digit information has been used in many areas and has been widely spread in the Internet era because of its convenience. However, many ill-disposed attackers, such as spammers take advantage of such convenience to send unsolicited information, such as advertisements, frauds, and pornographic messages to mislead users and this might cause severe *** many spam filters have been proposed in detecting spams, they are vulnerable and could be misled by some carefully crafted adversarial *** this paper, we propose the marginal attack methods of generating such adversarial examples to fool a naive Bayesian spam ***, we propose three methods to select sensitive words from a sentence and add them at the end of the sentence. Through extensive experiments, we show that the generated adversarial examples could largely reduce the filter's detecting accuracy, e.g. by adding only one word, the accuracy could be reduced from 93.6% to 55.8%. Furthermore, we evaluate the transferability of the generated adversarial examples against other traditional filters such as logic regression, decision tree and linear support vector machine based filters. The evaluation results show that these filters' accuracy is also reduced dramatically; especially,the decision tree based filter's accuracy drops from 100%to 1.51% by inserting only one word.

关键词： Spam filtering Marginal attack Adversarial example Machine learning

Probability of rebound and eject of sand particles in wind-blown sand movement

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2007年第5期23卷 471-475页

作者： li xie Xiaojing Zheng Key Laboratory of Mechanics on Western Disaster and Environment Lanzhou University Lanzhou 730000 China

When incident particles impact into a sand bed in wind-blown sand movement, rebound of the incident particles and eject of the sand particles by the incident particles affect directly the development of wind sand flux. In order to obtain rebound and eject lift-off probability of the sand particles, we apply the particle-bed stochastic collision model presented in our pervious works to derive analytic solutions of velocities of the incident and impacted particles in the postcollision bed. In order to describe randomness inherent in the real particle-bed collision, we take the incident angle, the impact position and the direction of resultant action of sand particles in sand bed on the impacted sand particle as ran- dom variables, and calculate the rebound and eject velocities, angles and coefficients （ratio of rebound and eject velocity to incident velocity）. Numerical results are found in accordance with current experimental results. The rebound and eject liftoff probabilities versus the incident and creeping velocities are predicted.

关键词： Wind-blown sand movement Rebound andeject coefficient Rebound and eject lift-off probability

A fiber-section model based Timoshenko beam element using shear-bending interdependent shape function

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2013年第3期12卷 421-432页

作者： li Ning li Zhongxian xie lili School of Civil Engineering Tianjin University/Key Laboratory of Coast Civil Structure Safety Ministry of Education Institute of Engineering Mechanics China Earthquake Administration

A fiber-section model based Timoshenko beam element is proposed in this study that is founded on the nonlinear analysis of frame elements considering axial, flexural, and shear deformations. This model is achieved using a shear-bending interdependent formulation （SBIF）. The shape function of the element is derived from the exact solution of the homogeneous form of the equilibrium equation for the Timoshenko deformation *** proposed element is free from shear-locking. The sectional fiber model is constituted with a multi-axial plasticity material model, which is used to simulate the coupled shear-axial nonlinear behavior of each fiber. By imposing deformation compatibility conditions among the fibers, the sectional and elemental resisting forces are calculated. Since the SBIF shape functions are interactive with the shear-corrector factor for different shapes of sections, an iterative procedure is introduced in the nonlinear state determination of the proposed Timoshenko element. In addition, the proposed model tackles the geometric nonlinear problem by adopting a corotational coordinate transformation approach. The derivation procedure of the corotational algorithm of the SBIF Timoshenko element for nonlinear geometrical analysis is presented. Numerical examples confirm that the SBIF Timoshenko element with a fiber-section model has the same accuracy and robustness as the flexibility-based formulation. Finally, the SBIF Timoshenko element is extended and demonstratedin a three-dimensional numerical example.

关键词： Timoshenko beam shear-flexure coupled effect shear-bending interdependent formulation nonlineargeometric analysis finite element

在线全文

学校读者我要写书评

暂无评论

糖尿病早期视网膜神经变性研究新进展

国际眼科杂志 2025年第1期25卷 76-81页

作者：魏凡彭立谢青中南大学湘雅医学院附属海口医院眼科海南省海口市570208

糖尿病视网膜病变(DR)是由慢性高血糖引起的晚期微神经血管并发症,可导致血-视网膜屏障受损和视网膜功能障碍。近年来研究发现,糖尿病视网膜神经变性(DN)可能是糖尿病的视网膜改变最早事件之一,主要表现包括:新诊断糖尿病患者的视网膜... 详细信息

糖尿病视网膜病变(DR)是由慢性高血糖引起的晚期微神经血管并发症,可导致血-视网膜屏障受损和视网膜功能障碍。近年来研究发现,糖尿病视网膜神经变性(DN)可能是糖尿病的视网膜改变最早事件之一,主要表现包括:新诊断糖尿病患者的视网膜电图反应缺陷;发病初期,小胶质细胞和Müller细胞在几周内自我激活并激活相关蛋白;神经递质(如DOPA/GABA)活性降低,损害神经节信号传递;早期线粒体功能障碍,如Drp1-Fis1持续裂变及mtDNA甲基化和碱基错配之间的潜在串扰等。探讨糖尿病早期视网膜神经变性的分子基础对于理解DN的发病机制及早期治疗至关重要。文章总结糖尿病早期视网膜感光功能及神经胶质细胞、神经递质、线粒体和其他因子的病理变化及机制,旨在为研究DN早期机制及靶向治疗提供理论依据。

关键词：糖尿病视网膜病变糖尿病视网膜神经变性视网膜电图线粒体自噬神经胶质细胞多巴胺

Catalysts design for CO_(2) electroreduction

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2022年第3期65卷 425-427页

作者： li li Yongfu Sun Yi xie Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of ChinaHefei 230026China

To create a harmonious society and mitigate fossil economy,efficient CO_(2)reducing is a critical step and is urgently ***_(2)electroreduction (ECO_(2)RR) technology,which converts greenhouse CO_(2)to chemical feedstocks and liquid fuels with renewable electricity,is a promising answer to "Carbon Neutrality" and "Paris Agreement"[1].Despite the great potential of CO_(2)electroreduction for energy and environment issues,it is still challenging of this technology.

关键词： convert harmonious critical

Extraction of vanadium from high calcium vanadium slag using direct roasting and soda leaching

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2012年第7期19卷 595-601页

作者： Xin-sheng li Bing xie College of Materials Science and Engineering Chongqing University Chongqing 400044 China

The extraction of vanadium from high calcium vanadium slag was attempted by direct roasting and soda leaching. The oxidation process of the vanadium slag at different temperatures was investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The effects of roasting temperature, roasting time, Na2CO3 concentration, leaching tem- perature, leaching time, and liquid to solid ratio on the extraction of vanadium were studied. The results showed that olivine phases and spinel phases in the vanadium slag were completely decomposed at 500 and 800℃, respectively. Vanadium-rich phases were formed at above 850℃. The leaching rate of vanadium reached above 90% under the optimum conditions： roasting temperature of 850℃, roasting time of 60 min, Na2CO3 concentration of 160 g/L, leaching temperature of 95℃, leaching time of 150 min, and liquid to solid ratio of 10：1 mL/g. The main impurities were Si and P in the leach liquor.

关键词： vanadium metallurgy extraction slag roasting leaching