The Distributed Queue Dual Bus(DQDB) Metropolitan Area Network(MAN) is a promising solution for the evolution from current networks to B-ISDN. The performance of the DQDB MAN for Local Area Networks(LANs) interconnect...The Distributed Queue Dual Bus(DQDB) Metropolitan Area Network(MAN) is a promising solution for the evolution from current networks to B-ISDN. The performance of the DQDB MAN for Local Area Networks(LANs) interconnection is analyzed. The effects of message length, traffic load of upstream and downstream nodes and the parameters of bandwidth balancing mechanism and network counters on the sojourn time of message in the buffer are investigated, which present a valuable reference for the implementation of the DQDB MAN.展开更多
For wired local area networks(LANs),their effectiveness and invulnerability are very critical.It is extraordinarily significant to evaluate the network performance effectively in the design of a reasonable network top...For wired local area networks(LANs),their effectiveness and invulnerability are very critical.It is extraordinarily significant to evaluate the network performance effectively in the design of a reasonable network topology and the performance improvement of the networks.However,there are many factors affecting the performance of the networks,and the relation among them is also complicated.How to evaluate the performance of the wired LANs more accurately has been a heavy challenge in the network research.In order to solve the problem,this paper presents a performance evaluation method that evaluates the effectiveness and invulnerability of the wired LANs.Compared to traditional statistical methods,it has the distinct advantage of being able to handle several dependent variables simultaneously and tolerates the measurement errors among these independent variables and dependent variables.Finally,the rationality and validity of this method are verified by the extensive experimental simulation.展开更多
iPod的魅力让其他任何厂商的任何数码播放器系列都望尘莫及，而iProne的推出在改变人们对手机传统认识的时候，也再一次捍卫和巩固了苹果产品尊贵的地位。竞争对手得到的压力空前巨大，但配件厂商却积极地加入到和苹果产品一起发展的行...iPod的魅力让其他任何厂商的任何数码播放器系列都望尘莫及，而iProne的推出在改变人们对手机传统认识的时候，也再一次捍卫和巩固了苹果产品尊贵的地位。竞争对手得到的压力空前巨大，但配件厂商却积极地加入到和苹果产品一起发展的行列当中，过去的“Made for iPod”战略也逐渐扩展到了“Made for iPhone”，实现苹果和配件厂商双赢的效果。展开更多
Wireless Local Area Networks (WLANs) such as IEEE 802.11a/g and Hiperlan/2 utilise numerous transmission modes, each providing different throughputs and reliability levels. Many link adaptation algorithms proposed in ...Wireless Local Area Networks (WLANs) such as IEEE 802.11a/g and Hiperlan/2 utilise numerous transmission modes, each providing different throughputs and reliability levels. Many link adaptation algorithms proposed in the literature either maximise the error-free data throughput based on channel conditions or are based on the number of failed transmissions. However, these algo- rithms do not take into account the content of the data stream and strongly rely on the use of Automatic Repeat Requests (ARQs). Low latency video applications such as real-time video transmission may require no retransmission, or only a limited number of retrans- missions. Moreover, completely error-free communication is not essential, especially if robust video compression techniques are applied. In such scenarios, improved decoded video quality can be obtained with a video stream transmitted at a higher bit rate using a higher link speed but with some degree of transmission error, rather than an error-free video stream at a lower bit rate using a lower link speed. In this work, we investigate a link adaptation scheme that improves the Quality of Service (QoS) for video transmission, based on the overall received video quality (Peak Signal to Noise Ratio, PSNR), rather than by maximising the error-free throughput. We also study a practical link adaptation approach that uses PER thresholds at the PHY layer. An empirical study showed that thresholds for switching from one mode to another are much lower (almost error free) than those currently used by throughput based schemes. We show that traditional link adaptation strategies are not appropriate for real-time video transmission with no retransmis- sion. Simulation results using the H.264 video compression standard over IEEE 802.11a are presented.展开更多
Problems of the current IGMP mechanism were identified, such as unnecessary periodic probing of hosts and leave latency, which wastes bandwidth and cause more traffic and overhead. Alternative mechanism that preserve ...Problems of the current IGMP mechanism were identified, such as unnecessary periodic probing of hosts and leave latency, which wastes bandwidth and cause more traffic and overhead. Alternative mechanism that preserve the IP multicast model but employ join/leave messages to track local group membership for broadcast LANs (shared medium LANs) was proposed in this paper. We describe the implementation requirements of the new mechanism and compare it to existing one, demonstrating that join/leave approach is uniformly superior for the environment of broadcast LANs.展开更多
The purpose for this article is to research the relationship between public transportation and real estate based on the area of East Lansing.Two methods are mainly used to analyze the data:correlation analysis and mea...The purpose for this article is to research the relationship between public transportation and real estate based on the area of East Lansing.Two methods are mainly used to analyze the data:correlation analysis and means analysis with the help of Statistical Package for the Social Sciences(SPSS) data analyzing software.There are two analysis results:(1) the real estate,which is closer to public transportation,will have higher value than that is far from public transportation,and(2) the number of bus in one bus stop has no obvious relation with the value of real estate.Based on these results,real estate developers could build residential real estate close to public transportation or bring public transportation in their real estate community by contract with transportation corporations.In sum,they should reasonably use public transportation as attractive features to convince people to prefer to their houses.展开更多
Geographic information Systems （GiS） is being widely applied to official construction activities nowadays. This technique can not only display graphs for each spatial data displayed, but also provide a broad predict...Geographic information Systems （GiS） is being widely applied to official construction activities nowadays. This technique can not only display graphs for each spatial data displayed, but also provide a broad prediction and decision tool. The purpose of this paper is to describe the capabilities of GIS application in building a new parking facility in the city of East Lansing through wide analysis of the surrounding data. The results are displayed in maps and graphs. Finally, the recommendation area is selected using three criteria： proximity to the downtown area; the degree of VACANT; and distance from all buffers.展开更多
基金Supported by the National Natural Science Foundation of Chinathe Foundation of the Institute of Electronic Science of China
文摘The Distributed Queue Dual Bus(DQDB) Metropolitan Area Network(MAN) is a promising solution for the evolution from current networks to B-ISDN. The performance of the DQDB MAN for Local Area Networks(LANs) interconnection is analyzed. The effects of message length, traffic load of upstream and downstream nodes and the parameters of bandwidth balancing mechanism and network counters on the sojourn time of message in the buffer are investigated, which present a valuable reference for the implementation of the DQDB MAN.
基金supported by the National Natural Science Foundations of China (Nos.61572435,61472305, 61473222)the Ningbo Natural Science Foundations(Nos. 2016A610035,2017A610119)+1 种基金the Complex Electronic System Simulation Laboratory (No.DXZT-JC-ZZ-2015015)the Joint Fund of China State Shipbuilding Corporation(No.6141B03010103)
文摘For wired local area networks(LANs),their effectiveness and invulnerability are very critical.It is extraordinarily significant to evaluate the network performance effectively in the design of a reasonable network topology and the performance improvement of the networks.However,there are many factors affecting the performance of the networks,and the relation among them is also complicated.How to evaluate the performance of the wired LANs more accurately has been a heavy challenge in the network research.In order to solve the problem,this paper presents a performance evaluation method that evaluates the effectiveness and invulnerability of the wired LANs.Compared to traditional statistical methods,it has the distinct advantage of being able to handle several dependent variables simultaneously and tolerates the measurement errors among these independent variables and dependent variables.Finally,the rationality and validity of this method are verified by the extensive experimental simulation.
文摘iPod的魅力让其他任何厂商的任何数码播放器系列都望尘莫及，而iProne的推出在改变人们对手机传统认识的时候，也再一次捍卫和巩固了苹果产品尊贵的地位。竞争对手得到的压力空前巨大，但配件厂商却积极地加入到和苹果产品一起发展的行列当中，过去的“Made for iPod”战略也逐渐扩展到了“Made for iPhone”，实现苹果和配件厂商双赢的效果。
文摘Wireless Local Area Networks (WLANs) such as IEEE 802.11a/g and Hiperlan/2 utilise numerous transmission modes, each providing different throughputs and reliability levels. Many link adaptation algorithms proposed in the literature either maximise the error-free data throughput based on channel conditions or are based on the number of failed transmissions. However, these algo- rithms do not take into account the content of the data stream and strongly rely on the use of Automatic Repeat Requests (ARQs). Low latency video applications such as real-time video transmission may require no retransmission, or only a limited number of retrans- missions. Moreover, completely error-free communication is not essential, especially if robust video compression techniques are applied. In such scenarios, improved decoded video quality can be obtained with a video stream transmitted at a higher bit rate using a higher link speed but with some degree of transmission error, rather than an error-free video stream at a lower bit rate using a lower link speed. In this work, we investigate a link adaptation scheme that improves the Quality of Service (QoS) for video transmission, based on the overall received video quality (Peak Signal to Noise Ratio, PSNR), rather than by maximising the error-free throughput. We also study a practical link adaptation approach that uses PER thresholds at the PHY layer. An empirical study showed that thresholds for switching from one mode to another are much lower (almost error free) than those currently used by throughput based schemes. We show that traditional link adaptation strategies are not appropriate for real-time video transmission with no retransmis- sion. Simulation results using the H.264 video compression standard over IEEE 802.11a are presented.
文摘Problems of the current IGMP mechanism were identified, such as unnecessary periodic probing of hosts and leave latency, which wastes bandwidth and cause more traffic and overhead. Alternative mechanism that preserve the IP multicast model but employ join/leave messages to track local group membership for broadcast LANs (shared medium LANs) was proposed in this paper. We describe the implementation requirements of the new mechanism and compare it to existing one, demonstrating that join/leave approach is uniformly superior for the environment of broadcast LANs.
文摘一句话：Lanstory：第一个能够同时容纳玩家和观众两种身份的场景由战旗打造的首届＂Lan Story战旗电竞总动员＂于8月25日-8月27日在上海国家会展中心举办。Lan Story起源于国外的Lan Party（局域网聚会）,核心理念是玩家带着自己的装备来参加活动（Bring Your Own Computer,简称BYOC）。此次,Lan Story邀请了多名知名主播和战队与粉丝互动。玩家在现场可以在端游区、手游区和街机区体验多款游戏。
文摘The purpose for this article is to research the relationship between public transportation and real estate based on the area of East Lansing.Two methods are mainly used to analyze the data:correlation analysis and means analysis with the help of Statistical Package for the Social Sciences(SPSS) data analyzing software.There are two analysis results:(1) the real estate,which is closer to public transportation,will have higher value than that is far from public transportation,and(2) the number of bus in one bus stop has no obvious relation with the value of real estate.Based on these results,real estate developers could build residential real estate close to public transportation or bring public transportation in their real estate community by contract with transportation corporations.In sum,they should reasonably use public transportation as attractive features to convince people to prefer to their houses.
文摘Geographic information Systems （GiS） is being widely applied to official construction activities nowadays. This technique can not only display graphs for each spatial data displayed, but also provide a broad prediction and decision tool. The purpose of this paper is to describe the capabilities of GIS application in building a new parking facility in the city of East Lansing through wide analysis of the surrounding data. The results are displayed in maps and graphs. Finally, the recommendation area is selected using three criteria： proximity to the downtown area; the degree of VACANT; and distance from all buffers.
