期刊文献+
共找到13,487篇文章
< 1 2 250 >
每页显示 20 50 100
基于Packet Tracer的虚拟医疗网络设计与性能分析
1
作者 石莉 王芳 +2 位作者 闫实 金松根 仇彬 《电脑编程技巧与维护》 2024年第5期38-40,共3页
在Packet Tracer模拟环境中针对虚拟医疗网络进行设计与性能分析。系统需求与设计部分详细考虑了医疗网络的功能需求、拓扑设计和安全性措施。通过Packet Tracer模拟环境的建立,成功模拟了医院内部网络、医疗设备网络和远程连接,符合实... 在Packet Tracer模拟环境中针对虚拟医疗网络进行设计与性能分析。系统需求与设计部分详细考虑了医疗网络的功能需求、拓扑设计和安全性措施。通过Packet Tracer模拟环境的建立,成功模拟了医院内部网络、医疗设备网络和远程连接,符合实际医疗场景。在性能分析中,使用Packet Tracer工具对带宽、延迟、安全性和可靠性进行了全面评估。通过优化网络配置,确保实时医疗应用的高效运行,同时强调了网络的安全性和可靠性。这一综合性的设计和性能分析为虚拟医疗网络的实际部署提供了有力的支持。 展开更多
关键词 packet Tracer工具 医疗网络 虚拟网络 网络性能
下载PDF
Quantum Mechanics: Harmonic Wave-Packets, Localized by Resonant Response in Dispersion Dynamics
2
作者 Antony J. Bourdillon 《Journal of Modern Physics》 CAS 2023年第2期171-182,共12页
From a combination of Maxwell’s electromagnetism with Planck’s law and the de Broglie hypothesis, we arrive at quantized photonic wave groups whose constant phase velocity is equal to the speed of light c = ω/k and... From a combination of Maxwell’s electromagnetism with Planck’s law and the de Broglie hypothesis, we arrive at quantized photonic wave groups whose constant phase velocity is equal to the speed of light c = ω/k and to their group velocity dω/dk. When we include special relativity expressed in simplest units, we find that, for particulate matter, the square of rest mass , i.e., angular frequency squared minus wave vector squared. This equation separates into a conservative part and a uniform responsive part. A wave function is derived in manifold rank 4, and from it are derived uncertainties and internal motion. The function solves four anomalies in quantum physics: the point particle with prescribed uncertainties;spooky action at a distance;time dependence that is consistent with the uncertainties;and resonant reduction of the wave packet by localization during measurement. A comparison between contradictory mathematical and physical theories leads to similar empirical conclusions because probability amplitudes express hidden variables. The comparison supplies orthodox postulates that are compared to physical principles that formalize the difference. The method is verified by dual harmonics found in quantized quasi-Bloch waves, where the quantum is physical;not axiomatic. 展开更多
关键词 Wave packet Reduction Phase Velocity Hidden Variables Young’s Slits Resonant Response Dispersion Dynamics Quantum Physics
下载PDF
Enhanced Fourier Transform Using Wavelet Packet Decomposition
3
作者 Wouladje Cabrel Golden Tendekai Mumanikidzwa +1 位作者 Jianguo Shen Yutong Yan 《Journal of Sensor Technology》 2024年第1期1-15,共15页
Many domains, including communication, signal processing, and image processing, use the Fourier Transform as a mathematical tool for signal analysis. Although it can analyze signals with steady and transitory properti... Many domains, including communication, signal processing, and image processing, use the Fourier Transform as a mathematical tool for signal analysis. Although it can analyze signals with steady and transitory properties, it has limits. The Wavelet Packet Decomposition (WPD) is a novel technique that we suggest in this study as a way to improve the Fourier Transform and get beyond these drawbacks. In this experiment, we specifically considered the utilization of Daubechies level 4 for the wavelet transformation. The choice of Daubechies level 4 was motivated by several reasons. Daubechies wavelets are known for their compact support, orthogonality, and good time-frequency localization. By choosing Daubechies level 4, we aimed to strike a balance between preserving important transient information and avoiding excessive noise or oversmoothing in the transformed signal. Then we compared the outcomes of our suggested approach to the conventional Fourier Transform using a non-stationary signal. The findings demonstrated that the suggested method offered a more accurate representation of non-stationary and transient signals in the frequency domain. Our method precisely showed a 12% reduction in MSE and a 3% rise in PSNR for the standard Fourier transform, as well as a 35% decrease in MSE and an 8% increase in PSNR for voice signals when compared to the traditional wavelet packet decomposition method. 展开更多
关键词 Fourier Transform Wavelet packet Decomposition Time-Frequency Analysis Non-Stationary Signals
下载PDF
基于PacketTracer和Onenet的物联网家居系统
4
作者 黄良歌 叶成荫 +2 位作者 程少杰 侯旭晖 武旭鹏 《移动信息》 2024年第6期313-315,共3页
针对实物物联网家居成本过高、搭建过程复杂的问题,文中使用PacketTracer和OneNet云平台设计了一种物联网智能家居系统。该系统使用PacketTracer方法进行了设计,并通过MCU将智能家居设备远程接入OneNet云平台。测试结果表明,与传统的实... 针对实物物联网家居成本过高、搭建过程复杂的问题,文中使用PacketTracer和OneNet云平台设计了一种物联网智能家居系统。该系统使用PacketTracer方法进行了设计,并通过MCU将智能家居设备远程接入OneNet云平台。测试结果表明,与传统的实物物联网家居相比,该系统不仅缩短了设计周期,还能实现对家居设备的远程控制。 展开更多
关键词 物联网家居 packet Tracer OneNet云平台 远程控制
下载PDF
Machine-Learning Based Packet Switching Method for Providing Stable High-Quality Video Streaming in Multi-Stream Transmission
5
作者 Yumin Jo Jongho Paik 《Computers, Materials & Continua》 SCIE EI 2024年第3期4153-4176,共24页
Broadcasting gateway equipment generally uses a method of simply switching to a spare input stream when a failure occurs in a main input stream.However,when the transmission environment is unstable,problems such as re... Broadcasting gateway equipment generally uses a method of simply switching to a spare input stream when a failure occurs in a main input stream.However,when the transmission environment is unstable,problems such as reduction in the lifespan of equipment due to frequent switching and interruption,delay,and stoppage of services may occur.Therefore,applying a machine learning(ML)method,which is possible to automatically judge and classify network-related service anomaly,and switch multi-input signals without dropping or changing signals by predicting or quickly determining the time of error occurrence for smooth stream switching when there are problems such as transmission errors,is required.In this paper,we propose an intelligent packet switching method based on the ML method of classification,which is one of the supervised learning methods,that presents the risk level of abnormal multi-stream occurring in broadcasting gateway equipment based on data.Furthermore,we subdivide the risk levels obtained from classification techniques into probabilities and then derive vectorized representative values for each attribute value of the collected input data and continuously update them.The obtained reference vector value is used for switching judgment through the cosine similarity value between input data obtained when a dangerous situation occurs.In the broadcasting gateway equipment to which the proposed method is applied,it is possible to perform more stable and smarter switching than before by solving problems of reliability and broadcasting accidents of the equipment and can maintain stable video streaming as well. 展开更多
关键词 Broadcasting and communication convergence multi-stream packet switching advanced television systems committee standard 3.0(ATSC 3.0) data pre-processing machine learning cosine similarity
下载PDF
基于Packet Tracer的VLAN间路由仿真实验设计
6
作者 王金蕾 李佳佳 《电脑编程技巧与维护》 2024年第8期157-160,共4页
每个虚拟局域网(VLAN)在逻辑上都相当于一个独立的网络,拥有自己的广播域,VLAN之间不能直接通信,但是有时候又需要在不同网段间跨VLAN进行通信,因此研究使用Packet Tracer模拟软件实现了不同VLAN间路由的配置。
关键词 虚拟局域网 单臂路由 packet Tracer模拟软件
下载PDF
基于Smart Packets的主动网络管理模型研究
7
作者 马燕 邹显春 康庆 《计算机科学》 CSCD 北大核心 2004年第12期37-39,46,共4页
主动网络是一种新型的网络体系,它不仅可以传送数据包,而且还可以执行数据包中特定的运算任务。主动网络为用户提供了可编程的接口,用户可通过网络中的节点动态地注入所需的服务。Smart Packets采用紧缩格式和安全代码编写其中的程序,... 主动网络是一种新型的网络体系,它不仅可以传送数据包,而且还可以执行数据包中特定的运算任务。主动网络为用户提供了可编程的接口,用户可通过网络中的节点动态地注入所需的服务。Smart Packets采用紧缩格式和安全代码编写其中的程序,它能够支持主动网络管理。本文讨论了传统网络管理中存在的问题,分析了主动网络管理体系结构与管理机制。重点研究了Smart Packets的结构、管理机制、包的格式、编程语言和设计目标,以及安全性。 展开更多
关键词 主动网络 安全代码 行数据 编程语言 接口 传送数据 管理模型 用户 管理机制 服务
下载PDF
基于Packet Tracer的MQTT协议仿真实现 被引量:3
8
作者 刘国梅 《物联网技术》 2023年第11期45-47,共3页
MQTT协议是物联网设备云边传输最常用的通信协议之一。对于物联网相关专业、学科的学生来说,理解MQTT协议的工作原理、数据包结构、消息服务质量等非常重要。通过在Packet Tracer仿真软件上进行MQTT协议网络仿真结构设计、网络连通性配... MQTT协议是物联网设备云边传输最常用的通信协议之一。对于物联网相关专业、学科的学生来说,理解MQTT协议的工作原理、数据包结构、消息服务质量等非常重要。通过在Packet Tracer仿真软件上进行MQTT协议网络仿真结构设计、网络连通性配置、程序设计以及相应数据包抓取,仿真MQTT协议的工作过程,分析协议数据包的结构。经过仿真分析与理论分析的对比,进一步加深对MQTT协议的理解。 展开更多
关键词 物联网 MQTT协议 packet Tracer仿真软件 通信协议 云边传输 数据包
下载PDF
基于Cisco Packet Tracer的虚拟仿真软件在“计算机网络技术”实验教学中的应用研究
9
作者 王珂 刘文艳 +4 位作者 王宇 杨淼 沙飞 翟阳阳 辛欣 《中国信息技术教育》 2023年第20期86-90,共5页
作者介绍了Cisco Packet Tracer虚拟仿真软件的功能和优点,并根据当前“计算机网络技术”课程的实验教学现状,以“交换机虚拟局域网”实验为例说明Cisco Packet Tracer如何在“计算机网络技术”课程中实现虚拟仿真实验教学。通过问卷调... 作者介绍了Cisco Packet Tracer虚拟仿真软件的功能和优点,并根据当前“计算机网络技术”课程的实验教学现状,以“交换机虚拟局域网”实验为例说明Cisco Packet Tracer如何在“计算机网络技术”课程中实现虚拟仿真实验教学。通过问卷调查可知,虚拟仿真实验能够改善实验教学效果,降低实验成本,培养学生的实践操作能力和分析解决问题能力。 展开更多
关键词 Cisco packet Tracer 计算机网络技术 虚拟仿真 实验教学 实践操作
下载PDF
The Propagation of Wave Packets and Its Relationship with the Subtropical Jet over Southern China in January 2008 被引量:2
10
作者 左群杰 高守亭 吕达仁 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2013年第1期67-76,共10页
The propagation of wave packets and its relationship with the subtropical jet was investigated for the period 26 29 January 2008 over southern China using ECMWF Interim re-analysis data. Wave packets propagated from t... The propagation of wave packets and its relationship with the subtropical jet was investigated for the period 26 29 January 2008 over southern China using ECMWF Interim re-analysis data. Wave packets propagated from the north to the south side of an upper front with eastward development along the upper front during this period. Due to the eastward development of propagation, the acceleration of geostrophic westerly winds shifted eastward along the front. There were two primary sources of the propagation of wave packets at around 30°N. The first was the temperature inversion layer below 500 hPa, and the second was baroclinic zones located along the polarward flank of the subtropical jet in the middle and upper troposphere. Most wave packets propagated horizontally from the baroclinic zones and then converged on the zero meridional gradients of zonal winds. 展开更多
关键词 propagation of wave packets wave-mean flow interaction subtropical jet geopotential anomalies snowstorms
下载PDF
A CLASS OF BIDIMENSIONAL NONSEPARABLEWAVELET PACKETS 被引量:1
11
作者 田雄飞 李云章 《Acta Mathematica Scientia》 SCIE CSCD 2002年第1期131-137,共7页
2-band wavelet packets in L-2 (R-s) were constructed in [3]. In this note, a way to construct bidimensional orthonormal wavelet packets related to the dilation matrix M = ((1)(1) (1)(-1)) is obtained. M-wavelets are u... 2-band wavelet packets in L-2 (R-s) were constructed in [3]. In this note, a way to construct bidimensional orthonormal wavelet packets related to the dilation matrix M = ((1)(1) (1)(-1)) is obtained. M-wavelets are used ill quincunx subsampling in two dimensions for image processing. What is more., the approach of this paper can be generalized to construct wavelet packets in L-2 (R-s) related to a general diltion matrix. 展开更多
关键词 scaling function WAVELET wavelet packet
下载PDF
Interference of dissociating wave packets in the I_2 molecule driven by femtosecond laser pulses 被引量:1
12
作者 韩永昌 胡文辉 +1 位作者 于杰 丛书林 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第11期4834-4839,共6页
The interference between two dissociating wave packets of the I2 molecule driven by femtosecond laser pulses is theoreticaly studied by using the time-dependent quantum wave packet method. Both the internuclear distan... The interference between two dissociating wave packets of the I2 molecule driven by femtosecond laser pulses is theoreticaly studied by using the time-dependent quantum wave packet method. Both the internuclear distance-and velocity-dependent density functions are calculated and discussed. It is demonstrated that the interference pattern is determined by the phase difference and the delay time between two pump pulses. With two identical pulses with a delay time of 305 fs and a FWHM of 20 fs, more interference fringes can be observed, while with two pump pulses with a delay time of 80 fs and a FWHM of 20 fs, only a few interference fringes can be observed. 展开更多
关键词 PHOTODISSOCIATION interference of wave packets I2 molecule
下载PDF
Configuration for Predicting Travel-Time Using Wavelet Packets and Support Vector Regression 被引量:1
13
作者 Adeel Yusuf Vijay K. Madisetti 《Journal of Transportation Technologies》 2013年第3期220-231,共12页
Travel-time prediction has gained significance over the years especially in urban areas due to increasing traffic congestion. In this paper, the basic building blocks of the travel-time prediction models are discussed... Travel-time prediction has gained significance over the years especially in urban areas due to increasing traffic congestion. In this paper, the basic building blocks of the travel-time prediction models are discussed, with a small review of the previous work. A model for the travel-time prediction on freeways based on wavelet packet decomposition and support vector regression (WDSVR) is proposed, which used the multi-resolution and equivalent frequency distribution ability of the wavelet transform to train the support vector machines. The results are compared against the classical support vector regression (SVR) method. Our results indicated that the wavelet reconstructed coefficient when used as an input to the support vector machine for regression performed better (with selected wavelets only), when compared with the support vector regression model (without wavelet decomposition) with a prediction horizon of 45 minutes and more. The data used in this paper was taken from the California Department of Transportation (Caltrans) of District 12 with a detector density of 2.73, experiencing daily peak hours except most weekends. The data was stored for a period of 214 days accumulated over 5-minute intervals over a distance of 9.13 miles. The results indicated MAPE ranging from 12.35% to 14.75% against the classical SVR method with MAPE ranging from 12.57% to 15.84% with a prediction horizon of 45 minutes to 1 hour. The basic criteria for selection of wavelet basis for preprocessing the inputs of support vector machines are also explored to filter the set of wavelet families for the WDSVR model. Finally, a configuration of travel-time prediction on freeways is presented with interchangeable prediction methods. 展开更多
关键词 TRAVEL-TIME Prediction WAVELET packets Support VECTOR Regression Advanced TRAVELER Information System
下载PDF
利用WildPackets Etherpeek NX分析排除VLAN划分后校园网网络故障 被引量:2
14
作者 陈昱 王铁 《计算机安全》 2009年第8期95-96,共2页
通过软件WildPacket Etherpeek NX分析校园网络内已通过VLAN划分一段子网下发生网络拥塞和实时交互软件不能正常使用的案例,解决网络故障的技术,进一步分析了该软件的使用方法,希望对促进校园网网络安全有一定积极作用。
关键词 Wildpackets Etherpeek NX VLAN ARP 数据包 网络故障
下载PDF
Orthogonal Stacked Spectral Coding Labels for Fast Packets Routing over Optical MPLS Network 被引量:1
15
作者 Kai-Sheng Chen Chao-Chin Yang Jen-Fa Huang 《Journal of Electronic Science and Technology》 CAS CSCD 2015年第2期130-134,共5页
Multi-protocol label switching(MPLS) has the advantage of high efficiency in the second layer, which improves the performance of data packets routing. In this paper, a new structure to implement optical MPLS is prop... Multi-protocol label switching(MPLS) has the advantage of high efficiency in the second layer, which improves the performance of data packets routing. In this paper, a new structure to implement optical MPLS is proposed. We construct a code family for spectral-amplitude coding(SAC) labels in the optical MPLS networks. SAC labels are suitable for optical packet switching because they can be constructed and recognized quickly at each router. We use the label stacking to provide hierarchical routing to avoid swapping labels at each forwarding node and reduce system complexity. However, the phase-induced intensity noise(PIIN) appears due to the incoherent property of the light source when the stacked labels set makes the correlation decoding with the local node label,which degrades system performance. 展开更多
关键词 label hierarchical switching quickly routing decoding forwarding packet matches router
下载PDF
Characterizing Internet Backbone Traffic Based on Deep Packets Inpection and Deep Flows Inspection 被引量:4
16
作者 杨洁 袁仑 +3 位作者 林平 丛蓉 程钢 尼万-安瑟瑞 《China Communications》 SCIE CSCD 2012年第5期42-54,共13页
Based on the massive data collected with a passive network monitoring equipment placed in China's backbone,we present a deep insight into the network backbone traffic and evaluate various ways for improving traffi... Based on the massive data collected with a passive network monitoring equipment placed in China's backbone,we present a deep insight into the network backbone traffic and evaluate various ways for improving traffic classifying efficiency in this paper.In particular,the study has scrutinized the network traffic in terms of protocol types and signatures,flow length,and port distribution,from which meaningful and interesting insights on the current Internet of China from the perspective of both the packet and flow levels are derived.We show that the classification efficiency can be greatly improved by using the information of preferred ports of the network applications.Quantitatively,we find two traffic duration thresholds,with which 40% of TCP flows and 70% of UDP flows can be excluded from classification processing while the impact on classification accuracy is trivial,i.e.,the classification accuracy can still reach a high level by saving 85% of the resources. 展开更多
关键词 互联网骨干网 净流量 基础 检查 流动 表征 网络应用 信息分类
下载PDF
Diagnosis of Gearbox Typical Fault in Rolling Mills Based on the Wavelet Packets Technology
17
作者 CUI Lingli GAO Lixin ZHANG Jianyu DING Fang College of Mechanical Engineering and Applied Electronics Technology,Beijing University of Technology,Advanced Manufacturing Technology,The Key Laboratory of Beijing Municipality,Beijing 100022,China, 《武汉理工大学学报》 CAS CSCD 北大核心 2006年第S3期1042-1045,共4页
The early impulse fault diagnosis of the gearbox in rolling mills is often difficult and labour intensive because the gearbox of that high speed machine is multi-shafting transmission system,in which many gearsets and... The early impulse fault diagnosis of the gearbox in rolling mills is often difficult and labour intensive because the gearbox of that high speed machine is multi-shafting transmission system,in which many gearsets and rolling bears work together at the same time and there are much complex frequency structure and various disturb.A new time-frequency method based on the wavelet packets technique was developed and used to extract the impact feature from signals collected from faulty data of one rolling mills gearbox.The method improves the signal to noise ration so that results obtained using this method represents features with fine resolution in both low-frequency and the high frequency bands.The results of analysis indicate the validity and the practicability of the method proposed here. 展开更多
关键词 FAULT DIAGNOSIS feature extraction rolling MILLS GEARBOX wavelet packets
下载PDF
Construction of Multivariate Tight Framelet Packets Associated with Dilation Matrix
18
作者 Firdous A.Shah Abdullah 《Analysis in Theory and Applications》 CSCD 2015年第2期109-122,共14页
In this paper, we present a method for constructing multivariate tight framelet packets associated with an arbitrary dilation matrix using unitary extension principles. We also prove how to construct various tight fra... In this paper, we present a method for constructing multivariate tight framelet packets associated with an arbitrary dilation matrix using unitary extension principles. We also prove how to construct various tight frames for L2 (JRa) by replacing some mother framelets. 展开更多
关键词 WAVELET tight frame framelet packet matrix dilation extension principle Fouriertransform.
下载PDF
Some Results on Wavelet Frame Packets
19
作者 Sana Khan Mohammad Kalimuddin Ahmad 《Advances in Pure Mathematics》 2014年第11期601-609,共9页
The aim of this paper is to study wavelet frame packets in which there are many frames. It is a generalization of wavelet packets. We derive few results on wavelet frame packets and have obtained the corresponding fra... The aim of this paper is to study wavelet frame packets in which there are many frames. It is a generalization of wavelet packets. We derive few results on wavelet frame packets and have obtained the corresponding frame bounds. 展开更多
关键词 WAVELET WAVELET packets FRAME packets
下载PDF
THEORY OF ORTHONORMAL M-BAND WAVELET PACKETS
20
作者 Zhang Jiankang Bao Zheng Jiao Licheng (Key Lab. for Radar Signal Processing, Xidian University, Xi’an 710071) 《Journal of Electronics(China)》 1998年第3期193-198,共6页
In recent years, M-band orthonormal wavelet bases, due to their good characteristics, have attracted much attention. The ability of 2-band wavelet packets to decompose high frequency channels can be employed to improv... In recent years, M-band orthonormal wavelet bases, due to their good characteristics, have attracted much attention. The ability of 2-band wavelet packets to decompose high frequency channels can be employed to improve the performance of wavelets for time-frequency localization, which makes more kinds of signals for analyzing by wavelets. Similar to the notations from the extension of 2-band wavelets to 2-band wavelet packets, the theoretic framework of M-band wavelet packets is developed, a generalization of the notations and properties of 2-band wavelet packets to that of M-band wavelet packets is made and the corresponding proofs are given. 展开更多
关键词 2-band WAVELETS M-BAND WAVELETS WAVELET packets
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部