期刊文献+
共找到681篇文章
< 1 2 35 >
每页显示 20 50 100
A FUNCTION NODE-BASED MULTIPLE PAIRWISE KEYS MANAGEMENT PROTOCOL FOR WIRELESS SENSOR NETWORKS AND ENERGY CONSUMPTION ANALYSIS
1
作者 Bi Jiana Wang Hui Sun Yandong Liu Yanzhao Ji Zhenzhou 《Journal of Electronics(China)》 2009年第5期692-698,共7页
In this letter, a Function node-based Multiple Pairwise Keys Management (MPKMF) protocol for Wireless Sensor Networks (WSNs) is firstly designed, in which ordinary nodes and cluster head nodes are responsible for data... In this letter, a Function node-based Multiple Pairwise Keys Management (MPKMF) protocol for Wireless Sensor Networks (WSNs) is firstly designed, in which ordinary nodes and cluster head nodes are responsible for data collection and transmission, and function nodes are responsible for key management. There are more than one function nodes in the cluster consulting the key generation and other security decision-making. The function nodes are the second-class security center because of the characteristics of the distributed WSNs. Secondly, It is also described that the formation of function nodes and cluster heads under the control of the former, and five kinds of keys, i.e., individual key, pairwise keys, cluster key, management key, and group key. Finally, performance analysis and experiments show that, the protocol is superior in communication and energy consumption. The delay of establishing the cluster key meets the requirements, and a multiple pairwise key which adopts the coordinated security authentication scheme is provided. 展开更多
关键词 Wireless Sensor Networks (WSNs) function nodes Key management Energy consumption
在线阅读 下载PDF
The comparative studies of the influences of Urapidil and Nicardipine on sino-atrial node function,atrio-ventricular node function and hemodynamics
2
作者 Jingming Zhu Ningning Hui Xiuhong Jiang Huaxing Zhang Chengzhang Fu 《Journal of Nanjing Medical University》 2007年第6期386-389,共4页
Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function, atrio-ventricular node function and hemodynamics. Methods:Thirty-two Angora' s rabbits were selected and randomly divide... Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function, atrio-ventricular node function and hemodynamics. Methods:Thirty-two Angora' s rabbits were selected and randomly divided into four groups. U1 group:urapidil 0.25 mg/kg; U2 group:urapidil 0.5 mg/kg; N1 group:nicardipine 10 μg/kg; N2 group: nicardipine 20 μg/kg. All these medicine were administrated within 30 seconds. Measurements were taken before and after the administration of urapidil or nicardipine for the following data: mean blood pressure(MAP), heart rate(HR), sino-atrial conduction time(SACT), maximal sinoatrial recovery time(SNRTmax) corrected sinus node recovery time(CSNRT), index of sinus node recovery time(SNRTI), Wenckebach A-V conduction frequency (WB), and P-R interval. Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine. No significant changes could be found in the rest of the parameters. Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P 〈 0.01); the MAP decreased(P 〈 0.01) and the HR increased drastically(P〈 0.01). Conclusions:Neither urapidil(0.25 mg/kg, 0,5 mg/kg) nor nicardipine(10 μg/kg, 20 μg/kg) has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function. Nicardipine could be a better choice than urapidil for parafunctional sinus node patients. 展开更多
关键词 URAPIDIL NICARDIPINE sinus function A-V node function HEMODYNAMICS
暂未订购
Extracting Multiple Nodes in a Brain Region of Interest for Brain Functional Network Estimation and Classification
3
作者 Chengcheng Wang Haimei Wang +1 位作者 Yifan Qiao Yining Zhang 《Journal of Applied Mathematics and Physics》 2022年第11期3408-3423,共16页
Purpose: Brain functional networks (BFNs) has become important approach for diagnosis of some neurological or psychological disorders. Before estimating BFN, obtaining blood oxygen level dependent (BOLD) representativ... Purpose: Brain functional networks (BFNs) has become important approach for diagnosis of some neurological or psychological disorders. Before estimating BFN, obtaining blood oxygen level dependent (BOLD) representative signals from brain regions of interest (ROIs) is important. In the past decades, the common method is generally to take a ROI as a node, averaging all the voxel time series inside it to extract a representative signal. However, one node does not represent the entire information of this ROI, and averaging method often leads to signal cancellation and information loss. Inspired by this, we propose a novel model extraction method based on an assumption that a ROI can be represented by multiple nodes. Methods: In this paper, we first extract multiple nodes (the number is user-defined) from the ROI based on two traditional methods, including principal component analysis (PCA), and K-means (Clustering according to the spatial position of voxels). Then, canonical correlation analysis (CCA) was issued to construct BFNs by maximizing the correlation between the representative signals corresponding to the nodes in any two ROIs. Finally, to further verify the effectiveness of the proposed method, the estimated BFNs are applied to identify subjects with autism spectrum disorder (ASD) and mild cognitive impairment (MCI) from health controls (HCs). Results: Experimental results on two benchmark databases demonstrate that the proposed method outperforms the baseline method in the sense of classification performance. Conclusions: We propose a novel method for obtaining nodes of ROId based on the hypothesis that a ROI can be represented by multiple nodes, that is, to extract the node signals of ROIs with K-means or PCA. Then, CCA is used to construct BFNs. 展开更多
关键词 Brain functional Network node Selection Pearson’s Correlation Canonical Correlation Analysis Brain Disorder Classification
在线阅读 下载PDF
An Approximation Algorithm for the solution of astrophysics equations using rational scaled generalized Laguerre function collocation method based on transformed Hermite-Gauss nodes
4
作者 Ali Pirkhedri Parisa Daneshjoo +3 位作者 Hamid Haj Seyyed Javadi Hamid Navidi Salem Khodamoradi Kamal Ghaderi 《International Journal of Astronomy and Astrophysics》 2011年第2期67-72,共6页
In this paper we propose a collocation method for solving Lane-Emden type equation which is nonlinear or-dinary differential equation on the semi-infinite domain. This equation is categorized as singular initial value... In this paper we propose a collocation method for solving Lane-Emden type equation which is nonlinear or-dinary differential equation on the semi-infinite domain. This equation is categorized as singular initial value problems. We solve this equation by the generalized Laguerre polynomial collocation method based on Her-mite-Gauss nodes. This method solves the problem on the semi-infinite domain without truncating it to a fi-nite domain and transforming domain of the problem to a finite domain. In addition, this method reduces so-lution of the problem to solution of a system of algebraic equations. 展开更多
关键词 Lane-Emden equation GENERALIZED Laguerre functions Collocation method Hermite-Gauss nodeS Nonlinear ODE SEMI-INFINITE
在线阅读 下载PDF
Coupling Magneto-Electro-Elastic node-based smoothed radial point interpolation method for free vibration and transient analysis of Functionally Graded Magneto-Electro-Elastic structures 被引量:2
5
作者 Liming ZHOU Shuhui REN +2 位作者 Bin NIE Guikai GUO Xiangyang CUI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2020年第1期227-243,共17页
A Coupling Magneto-Electro-Elastic(MEE)Node-based Smoothed Radial Point Interpolation Method(CM-NS-RPIM)was proposed to solve the free vibration and transient responses of Functionally Graded Magneto-Electro-Elastic(F... A Coupling Magneto-Electro-Elastic(MEE)Node-based Smoothed Radial Point Interpolation Method(CM-NS-RPIM)was proposed to solve the free vibration and transient responses of Functionally Graded Magneto-Electro-Elastic(FGMEE)structures.By introducing the modified Newmark method,the displacement,electrical potential and magnetic potential of the structures under transient mechanical loading were obtained.Based on G space theory and the weakened weak(W2)formulation,the equations of the multi-physics coupling problems were derived.Using triangular background elements,the free vibration and transient responses of three numerical examples were studied.Results proved that CM-NS-RPIM performed better than the standard FEM by reducing the overly-stiff of structures.Moreover,CM-NS-RPIM could reduce the number of nodes while guaranteeing the accuracy.Besides,triangular elements could be generated automatically even for complex geometries.Therefore,the effectiveness and validity of CM-NS-RPIM were demonstrated,which were valuable for the design of intelligence devices,such as energy harvesters and sensors. 展开更多
关键词 COUPLING MAGNETO-ELECTRO-ELASTIC node-based smoothed radial point interpolation method functionally Graded MAGNETO-ELECTRO-ELASTIC Gradient smoothing technique Rayleigh damping Transient responses
原文传递
Precision surgical approach with lymph-node dissection in early gastric cancer 被引量:30
6
作者 Shinichi Kinami Naohiko Nakamura +4 位作者 Yasuto Tomita Takashi Miyata Hideto Fujita Nobuhiko Ueda Takeo Kosaka 《World Journal of Gastroenterology》 SCIE CAS 2019年第14期1640-1652,共13页
The gravest prognostic factor in early gastric cancer is lymph-node metastasis,with an incidence of about 10% overall. About two-thirds of early gastric cancer patients can be diagnosed as node-negative prior to treat... The gravest prognostic factor in early gastric cancer is lymph-node metastasis,with an incidence of about 10% overall. About two-thirds of early gastric cancer patients can be diagnosed as node-negative prior to treatment based on clinicpathological data. Thus, the tumor can be resected by endoscopic submucosal dissection. In the remaining third, surgical resection is necessary because of the possibility of nodal metastasis. Nevertheless, almost all patients can be cured by gastrectomy with D1+ lymph-node dissection. Laparoscopic or robotic gastrectomy has become widespread in East Asia because perioperative and oncological safety are similar to open surgery. However, after D1+ gastrectomy,functional symptoms may still result. Physicians must strive to minimize postgastrectomy symptoms and optimize long-term quality of life after this operation.Depending on the location and size of the primary lesion, preservation of the pylorus or cardia should be considered. In addition, the extent of lymph-node dissection can be individualized, and significant gastric-volume preservation can be achieved if sentinel node biopsy is used to distinguish node-negative patients.Though the surgical treatment for early gastric cancer may be less radical than in the past, the operative method itself seems to be still in transition. 展开更多
关键词 STOMACH neoplasms SURGERY GASTRECTOMY methods Recovery of function SENTINEL LYMPH node SURGERY Gastric cancer
暂未订购
Health-related quality of life evaluated by tumor node metastasis staging system in patients with hepatocellular carcinoma 被引量:11
7
作者 Cui-Xia Qiao Xiao-Feng Zhai +4 位作者 Chang-Quan Ling Qing-Bo Lang Hui-Juan Dong Qun Liu Mou-Duo Li 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第21期2689-2694,共6页
AIM: To investigate and evaluate the change in healthrelated quality of life (HRQoL) by tumor node metastasis (TNM) staging system in patients with hepatocellular carcinoma (HCC). METHODS: A total of 140 patients diag... AIM: To investigate and evaluate the change in healthrelated quality of life (HRQoL) by tumor node metastasis (TNM) staging system in patients with hepatocellular carcinoma (HCC). METHODS: A total of 140 patients diagnosed with HCC between June 2008 and April 2009 in our department were enrolled to this study. One hundred and thirty-five (96.5%) patients had liver cirrhosis secondary to hepatitis B virus (HBV) infection, 73 (54.07%) of them being HBV DNA positive; the other etiologies of liver cirrhosis were alcoholic liver disease (1.4%), hepatitis C (1.4%) or cryptogenic (0.7%). All subjects were fully aware of their diagnosis and provided informed consent. HRQoL was assessed before treatment using the functional assessment of cancer therapy-hepatobiliary (FACT-Hep) questionnaire. Descriptive statistics were used to evaluate demographics and disease-specific characteristics of the patients. One-way analysis of variance and independent samples t tests were used to compare the overall FACT-Hep scores and clinically distinct TNM stages. Scores for all FACT-Hep items were analyzed by frequency analyses. The mean scores obtained from the FACT-Hep in different Child-Pugh classes were also evaluated. RESULTS: The mean FACT-Hep scores were reduced significantly from TNM StageⅠto Stage Ⅱ, Stage ⅢA, Stage ⅢB group (687 ± 39.69 vs 547 ± 42.57 vs 387 ± 51.24 vs 177 ± 71.44, P = 0.001). Regarding the physical and emotional well-being subscales, scores decreased gradually from Stage Ⅰ to Stage ⅢB (P = 0.002 vs Stage Ⅰ; P = 0.032 vs Stage Ⅱ; P = 0.033 vs Stage ⅢA). Mean FACT-Hep scores varied by Child-Pugh class, especially in the subscales of physical well-being, functional well-being and the hepatobiliary cancer (P = 0.001 vs Stage I; P = 0.036 vs Stage Ⅱ; P = 0.032 vs Stage ⅢA). For the social and family well-being subscale, only Stage ⅢB scores were significantly lower as compared with Stage Ⅰ scores (P = 0.035). For the subscales of functional well-being and hepatobiliary cancer, there were significant differences for Stages ⅡΙ, ⅢA and ⅢB (P = 0.002vs StageⅠ). CONCLUSION: HRQoL of patients with HCC worsens gradually with progression of TNM stages. The most impaired subscales of HRQoL, as measured by FACT-Hep, were physical and emotional well-being. 展开更多
关键词 Hepatocellular carcinoma Tumor node metastasis staging functional assessment of cancer therapy-hepatobiliary Health-related quality of life Cross-sectional study
在线阅读 下载PDF
Evidential method to identify influential nodes in complex networks 被引量:7
8
作者 Hongming Mo Cai Gao Yong Deng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第2期381-387,共7页
Identifying influential nodes in complex networks is still an open issue. In this paper, a new comprehensive centrality mea- sure is proposed based on the Dempster-Shafer evidence theory. The existing measures of degr... Identifying influential nodes in complex networks is still an open issue. In this paper, a new comprehensive centrality mea- sure is proposed based on the Dempster-Shafer evidence theory. The existing measures of degree centrality, betweenness centra- lity and closeness centrality are taken into consideration in the proposed method. Numerical examples are used to illustrate the effectiveness of the proposed method. 展开更多
关键词 Dempster-Shafer evidence theory (D-S theory) belief function complex networks influential nodes evidential centrality comprehensive measure
在线阅读 下载PDF
多障碍环境下巡检机器人路径规划优化研究 被引量:4
9
作者 乔道迹 张艳兵 《现代电子技术》 北大核心 2025年第1期130-134,共5页
针对大规模、密集的障碍物分布,高效地搜索最佳路径是一个挑战,为规划出更短的巡检路线,并实现多障碍环境下的灵活避障,文中提出一种多障碍环境下巡检机器人路径规划优化方法。使用二维矩阵构建巡检环境模型,应用D*算法在巡检环境模型... 针对大规模、密集的障碍物分布,高效地搜索最佳路径是一个挑战,为规划出更短的巡检路线,并实现多障碍环境下的灵活避障,文中提出一种多障碍环境下巡检机器人路径规划优化方法。使用二维矩阵构建巡检环境模型,应用D*算法在巡检环境模型中进行巡检机器人路径规划,并将传统D*算法中的扩展步长方式改变为自适应扩展步长,使机器人在面积较大的巡检场地能够更快地完成巡检;将代价函数由欧氏距离替换为切比雪夫诺距离和曼哈顿距离融合的代价函数,并引入了平滑度函数优化线路规划结果,使规划的路径更为平滑,在遇到由于多种原因产生的新障碍物时可以重新规划路径。通过实验结果可知,无论是静态地图还是动态地图,该方法均可以快速准确地规划出一条最佳路线,并且在多种环境中应用该方法能够高效获取路径规划结果。 展开更多
关键词 多障碍 巡检机器人 路径规划 D*算法 动态环境 扩展节点 代价函数 扩展步长
在线阅读 下载PDF
国际航空网络社区结构探测及枢纽节点挖掘
10
作者 秦昆 邢玲丽 +3 位作者 喻雪松 梁天祺 周扬 乔治浩 《同济大学学报(自然科学版)》 北大核心 2025年第12期1904-1914,共11页
采用2013―2022年的官方航空指南(Official Aviation Guide,OAG)数据,以国家/地区为节点、以节点之间的航空交通量为边构建加权国际航空网络(International Aviation Network,IAN)。通过Louvain算法识别IAN中的社区,并进一步分析其时空... 采用2013―2022年的官方航空指南(Official Aviation Guide,OAG)数据,以国家/地区为节点、以节点之间的航空交通量为边构建加权国际航空网络(International Aviation Network,IAN)。通过Louvain算法识别IAN中的社区,并进一步分析其时空演变规律;在社区探测的基础上,基于社区内z分数和参与系数挖掘结构性枢纽,基于核心度挖掘功能性枢纽。研究结果表明,IAN具有小世界特性,呈现多模块格局,自然地理、国际地缘政治等均对社区的形成产生影响;IAN在社区层面具有异质性,其特性反映了各社区有差异的航空合作模式;IAN社区结构整体稳定,但政治博弈等突发事件会导致社区结构发生变化;在IAN中,结构性枢纽约占5.0%,功能性枢纽约占7.6%。 展开更多
关键词 国际航空网络 社区结构 Louvain算法 结构性枢纽 功能性枢纽
在线阅读 下载PDF
基于障碍密度优先策略改进A^(*)算法的AGV路径规划 被引量:2
11
作者 陈一馨 段宇轩 +2 位作者 刘豪 谭世界 郑天乐 《郑州大学学报(工学版)》 北大核心 2025年第2期26-34,共9页
针对传统A^(*)算法在障碍物较多的实际场景下进行AGV路径规划时,存在路径拐点多、路径冗余节点过多以及易陷入局部最优解等问题,提出一种改进A^(*)算法,采用栅格法进行环境建模。首先,在启发函数中引入障碍物密度函数K(n)改进代价函数,... 针对传统A^(*)算法在障碍物较多的实际场景下进行AGV路径规划时,存在路径拐点多、路径冗余节点过多以及易陷入局部最优解等问题,提出一种改进A^(*)算法,采用栅格法进行环境建模。首先,在启发函数中引入障碍物密度函数K(n)改进代价函数,用于更准确地估计当前节点到目标节点的实际代价;其次,采用动态邻域搜索策略提高算法的搜索效率和运行效率;最后,通过冗余节点处理策略减少路径拐点和删除冗余节点,得到只包含起点、转折点以及终点的路径。采用不同尺寸和复杂度的栅格环境地图进行仿真实验,结果表明:所提改进A^(*)算法与传统A^(*)算法以及其他改进的A^(*)算法相比,路径长度分别缩短了4.71%和2.07%,路径拐点数量分别减少了45.45%和20.54%,路径存在节点分别减少了82.24%和62.45%。 展开更多
关键词 路径规划 栅格地图 改进A^(*)算法 启发函数 动态邻域搜索 冗余节点优化
在线阅读 下载PDF
DUAL RECIPROCITY HYBRID BOUNDARY NODE METHOD FOR THREE-DIMENSIONAL ELASTICITY WITH BODY FORCE 被引量:3
12
作者 Fei Yan Yuanhan Wang Yu Miao Fei Tan 《Acta Mechanica Solida Sinica》 SCIE EI 2008年第3期267-277,共11页
Combining Dual Reciprocity Method (DRM) with Hybrid Boundary Node Method (HBNM), the Dual Reciprocity Hybrid Boundary Node Method (DRHBNM) is developed for three-dimensional linear elasticity problems with body ... Combining Dual Reciprocity Method (DRM) with Hybrid Boundary Node Method (HBNM), the Dual Reciprocity Hybrid Boundary Node Method (DRHBNM) is developed for three-dimensional linear elasticity problems with body force. This method can be used to solve the elasticity problems with body force without domain integral, which is inevitable by HBNM. To demonstrate the versatility and the fast convergence of this method, some numerical examples of 3-D elasticity problems with body forces are examined. The computational results show that the present method is effective and can be widely applied in solving practical engineering problems. 展开更多
关键词 hybrid boundary node method dual reciprocity method body force radial basis function
在线阅读 下载PDF
The Next-Hop Node Selection Based GPSR in Vehicular Ad Hoc Networks
13
作者 Zhaoyuan Cui Demin Li +2 位作者 Guanglin Zhang Chang Guo Yong Sheng 《Journal of Computer and Communications》 2016年第10期44-56,共13页
Vehicular Ad hoc Networks (VANETs) which is a special form of Mobile Ad hoc Networks (MANETs) has promising application prospects in the future. Due to the rapid changing of topology structure, how to find a route whi... Vehicular Ad hoc Networks (VANETs) which is a special form of Mobile Ad hoc Networks (MANETs) has promising application prospects in the future. Due to the rapid changing of topology structure, how to find a route which can guarantee Quality of Service (QoS) is an important issue in VANETs. This paper presents an improved Greedy Perimeter Stateless Routing (GPSR) protocol based on our proposed next-hop node selection mechanism. Firstly, we define the link reliability in two cases which take the movement direction angle between two vehicles into consideration. Then we propose a next-hop node selection mechanism based on a weighted function which consists of link reliability between the sender node and next-hop candidate node, distance between next-hop candidate node and the destination, movement direction angle of next-hop candidate node. At last, an improved GPSR protocol is proposed based on the next-hop node selection mechanism. Simulation results are presented to evaluate the performance of the improved GPSR protocol, which shows that the performance including packet delivery ratio and average end-to-end delay of the proposed protocol is better in some situations. 展开更多
关键词 VANETS GPSR Next-Hop node Selection Link Reliability Weighted function
在线阅读 下载PDF
基于人工鱼群算法的网络覆盖优化方法研究
14
作者 汤隆 《自动化仪表》 2025年第4期97-100,106,共5页
无线传感网络随机部署移动节点时存在分布不均匀的问题,降低了网络带宽容量和网络覆盖率。为解决上述问题,基于人工鱼群算法的创新点,设计了网络覆盖优化方法。首先,分类处理不同角度的信号,设置多个基站,利用传感器的覆盖能力接收信号... 无线传感网络随机部署移动节点时存在分布不均匀的问题,降低了网络带宽容量和网络覆盖率。为解决上述问题,基于人工鱼群算法的创新点,设计了网络覆盖优化方法。首先,分类处理不同角度的信号,设置多个基站,利用传感器的覆盖能力接收信号,并确定目标函数。然后,将设置的目标函数作为训练目标,对人工鱼群算法进行预训练,并建立网络覆盖模型。最后,确定人工鱼群算法优化后的节点检测范围,以实现网络覆盖优化。试验结果表明,所提方法随着迭代次数和感知半径的增加,覆盖率逐渐稳定。所提方法能够提高网络覆盖率,并在短时间内找到最优解,从而满足设计需求。 展开更多
关键词 人工鱼群算法 无线传感网络 网络覆盖 目标函数 节点信号
在线阅读 下载PDF
基于小生境遗传算法的网络入侵节点智能检测方法 被引量:1
15
作者 王建刚 《吉林大学学报(理学版)》 北大核心 2025年第4期1099-1104,共6页
为降低网络入侵的风险,提出一种基于小生境遗传算法的网络入侵节点智能检测方法.首先,针对网络入侵的攻击行为进行聚合处理,利用双人攻防博弈模型分析网络的攻防状态,通过比对攻击与防御的效用强度,对网络的安全性进行全面分析,再根据... 为降低网络入侵的风险,提出一种基于小生境遗传算法的网络入侵节点智能检测方法.首先,针对网络入侵的攻击行为进行聚合处理,利用双人攻防博弈模型分析网络的攻防状态,通过比对攻击与防御的效用强度,对网络的安全性进行全面分析,再根据分析结果,通过卷积神经网络实现对攻击源的定位.其次,基于粗糙集理论,利用小生境遗传算法确定网络入侵节点检测的适应度函数,根据网络入侵节点智能检测规则,建立网络入侵节点智能检测模型,获得最终的检测结果.实验结果表明,该方法可有效提升对入侵攻击源的定位准确性和入侵节点检测准确性,该方法检测结果的宏F1分数大于0.96,表明该方法可有效实现设计预期. 展开更多
关键词 小生境遗传算法 网络入侵 入侵节点 粗糙集理论 适应度函数 入侵检测
在线阅读 下载PDF
工业无线传感器网络防移动干扰攻击节点的Stackelberg博弈
16
作者 孙子文 翟润华 杨晨曦 《传感技术学报》 北大核心 2025年第6期1081-1088,共8页
针对工业无线传感器网络k节点抗干扰攻击问题,研究一种抵御移动攻击节点的Stackelberg博弈模型。在攻击节点效用函数中加入以能量消耗函数、信道损耗函数和奖励收益函数为成本的代价函数,以约束节点的攻击效率。将移动Sink节点与移动攻... 针对工业无线传感器网络k节点抗干扰攻击问题,研究一种抵御移动攻击节点的Stackelberg博弈模型。在攻击节点效用函数中加入以能量消耗函数、信道损耗函数和奖励收益函数为成本的代价函数,以约束节点的攻击效率。将移动Sink节点与移动攻击节点之间的对抗交互行为建模为功率控制Stackelberg模型,通过求解博弈均衡解,给出节点移动位置下的最佳功率。MATLAB仿真结果表明,相比未引入成本代价函数的其他博弈功率控制方案,该方案能更有效地抑制移动攻击节点的干扰能力,同时提高移动k节点抵御干扰攻击的性能。 展开更多
关键词 工业无线传感器网络 STACKELBERG博弈 成本代价函数 干扰攻击 移动攻击节点
在线阅读 下载PDF
心房颤动心室率周期性变化的研究
17
作者 刘洪艳 《临床心电学杂志》 2025年第2期94-96,共3页
目的分析心房颤动(房颤)患者伴心室率周期性改变的临床特征、发生的可能机制及临床意义。方法选择2021年10月至2022年1月期间我院住院的房颤患者的动态心电图资料,通过1小时的时间RR间期散点图锯齿状改变判定心室率周期性变化的患者12例... 目的分析心房颤动(房颤)患者伴心室率周期性改变的临床特征、发生的可能机制及临床意义。方法选择2021年10月至2022年1月期间我院住院的房颤患者的动态心电图资料,通过1小时的时间RR间期散点图锯齿状改变判定心室率周期性变化的患者12例,其中男11例,女1例。结果房颤伴心室率周期性改变现象常发生于夜间睡眠状态;12例患者均为房颤伴充血性心力衰竭及左心疾病引起的轻、中度肺动脉高压,心功能Ⅱ~Ⅳ级。12例患中缺血性心肌病11例,扩张型心肌病1例。临床症状均有阵发性呼吸困难。其中男性居多,占83%。结论房颤伴心室率周期性改变常发生在夜间,多见于男性充血性心力衰竭且有左心疾病所致的轻、中度肺动脉高压患者。严重充血性心力衰竭易合并陈-施呼吸,使房室结功能不应期周期性变化进而房颤心室率周期性改变。 展开更多
关键词 心房颤动 房室结功能不应期 时间RR间期散点图 充血性心力衰竭 陈-施呼吸
原文传递
头颈肿瘤颈淋巴结清扫术后患者颈肩功能相关生活质量现状调查及影响因素分析
18
作者 任晓波 田梓蓉 +2 位作者 韦昌韵 刘永玲 许亚红 《中国医药导报》 2025年第7期98-103,共6页
目的 调查头颈肿瘤颈淋巴结清扫(以下简称“颈清扫”)术后患者颈肩功能相关生活质量现状并分析影响因素。方法 选取2024年6月至7月在首都医科大学附属北京同仁医院耳鼻咽喉头颈外科就诊的颈清扫术后患者作为研究对象。收集患者人口学资... 目的 调查头颈肿瘤颈淋巴结清扫(以下简称“颈清扫”)术后患者颈肩功能相关生活质量现状并分析影响因素。方法 选取2024年6月至7月在首都医科大学附属北京同仁医院耳鼻咽喉头颈外科就诊的颈清扫术后患者作为研究对象。收集患者人口学资料、疾病相关资料及颈肩功能相关生活质量,颈肩功能相关生活质量使用汉化版颈淋巴结清扫损伤指数(NDII)量表进行评估。采用多元线性回归方法分析头颈肿瘤颈清扫术后患者颈肩功能相关生活质量的影响因素。结果 不同性别、付费方式、教育程度、疾病类型、颈清扫类型、颈清扫侧别、有无放疗史、是否行颈肩功能锻炼的头颈肿瘤颈清扫术后患者NDII量表得分比较,差异有统计学意义(P<0.05)。疾病类型、颈清扫类型、颈清扫侧别、放疗史、行颈肩功能锻炼是头颈肿瘤颈清扫术后患者颈肩功能相关生活质量的影响因素(P<0.05)。结论 头颈肿瘤颈清扫术后患者会出现不同程度的颈肩功能相关生活质量降低,医务人员应重视头颈肿瘤颈清扫术后患者的颈肩功能情况,针对不同特征的患者进行个性化的颈肩功能锻炼,以降低此类患者术后颈肩功能障碍程度、改善生活质量。 展开更多
关键词 颈淋巴结清扫术 颈肩功能 头颈肿瘤
暂未订购
基于迹距离划分决策树的高炉故障诊断方法
19
作者 刘亚雪 张敬川 王显鹏 《控制与决策》 北大核心 2025年第5期1533-1540,共8页
随着工业自动化和智能化的发展,决策树模型在高炉故障诊断领域得到了广泛应用,但对于炼铁过程中存在高维度、非线性和强耦合的特点,传统决策树模型的构建容易陷入局部最优解,效率较低且复杂度较高.针对这些问题,首先引入迹距离函数,并... 随着工业自动化和智能化的发展,决策树模型在高炉故障诊断领域得到了广泛应用,但对于炼铁过程中存在高维度、非线性和强耦合的特点,传统决策树模型的构建容易陷入局部最优解,效率较低且复杂度较高.针对这些问题,首先引入迹距离函数,并证明在迹距离函数中任何局部最优解也是全局最优解的性质;接着针对决策树的节点分裂过程,提出一种基于迹距离划分的决策树模型,记作TraceTree.此模型一方面可以更快速地评价一个节点的划分效果,有效降低决策树模型的复杂度;另一方面能够识别出对故障诊断最有贡献的特征参数并获得更高的诊断精度.与其他改进模型的对比实验结果表明,所提出的模型在更短的训练时间内能取得最优的高炉故障诊断效果,及时地对高炉炉况进行监测与诊断. 展开更多
关键词 高炉炼铁过程 故障诊断 数据挖掘 决策树 迹距离函数 节点分裂
原文传递
一类具有恐惧效应和同类相食的捕食者-食饵模型 被引量:1
20
作者 李博涵 刘俊利 刘飞燕 《黑龙江大学自然科学学报》 2025年第1期27-36,共10页
为了研究恐惧效应和同类相食对捕食者-食饵模型的影响,在具有恐惧效应且功能反应函数为Holling-Ⅱ型的模型中加入了捕食者同类相食,证明了模型解的非负有界性,给出了平衡点存在的充分条件。运用线性化方法和构造Dulac函数,讨论了平衡点... 为了研究恐惧效应和同类相食对捕食者-食饵模型的影响,在具有恐惧效应且功能反应函数为Holling-Ⅱ型的模型中加入了捕食者同类相食,证明了模型解的非负有界性,给出了平衡点存在的充分条件。运用线性化方法和构造Dulac函数,讨论了平衡点的全局稳定性,研究了边界平衡点处的鞍结点分支和正平衡点处的Hopf分支。研究表明,较高的恐惧水平可以通过排除周期解的存在来确保捕食者-食饵模型的稳定,而较低的恐惧水平可以通过亚临界Hopf分支产生多个极限环,进而达到双稳定状态。与忽略捕食者同类相食的具有恐惧效应的捕食者-食饵模型相比,该模型表明更高的同类相食率更有利于模型的稳定。 展开更多
关键词 恐惧效应 同类相食 DULAC函数 Holling-Ⅱ型功能反应函数 鞍结点分支 HOPF分支
在线阅读 下载PDF
上一页 1 2 35 下一页 到第
使用帮助 返回顶部