In this paper, the open queueing network model is proposed for solving the problem of public transportation in cities. The vertices of the networks(i.e., the bus stops) are determined by means of the fuzzy clusteri...In this paper, the open queueing network model is proposed for solving the problem of public transportation in cities. The vertices of the networks(i.e., the bus stops) are determined by means of the fuzzy clustering method. The arcs (i.e., the paths of the public transportation) can be set up by using the shortest path model in the time sense or the 0 1 integer programming method.Applying the statistics method, we can calculate the parameters(such as the passenger flow's distribution, passenger flow's transition probability, mean waiting time for the bus etc. ) of the public transportation network. In this paper, we suggest to divide the network into two or three stages to implement the public transportation system in the form of ``frog jumping' fast transfer and ``permeation' fast dispersion.Combining the computer simulation and the evaluation of the achievement and effect of public transportation system, we modify the model so as to solve the public transportation problem better.展开更多
OSPF（Open Shortest Path First Protocol）协议是目前Internet上广泛使用的自治系统内部交换路由信息的动态路由协议。文章介绍了在清华大学研制的国产高性能路由器中分布式路由协议OSPF－2的具体实现。为了实现这一复杂的动态协议，...OSPF（Open Shortest Path First Protocol）协议是目前Internet上广泛使用的自治系统内部交换路由信息的动态路由协议。文章介绍了在清华大学研制的国产高性能路由器中分布式路由协议OSPF－2的具体实现。为了实现这一复杂的动态协议，文章提出了基于事件驱动的虚拟多任务机制的设计和实现方法。这种机制能够有效支持复杂系统的分解，在实时性要求不高的前提下提供一种简便有效的并行机制，方便基于状态机的软件实现，提高了软件的可移植性。该方法对于其它的Internet高层协议的设计和实现也有一定的参考价值。展开更多
开放式最短路径优先协议(Open Shortest Path First,OSPF)是一种基于链路状态的内部网关协议,其自身广泛的适应范围、较强的快速收敛能力、成熟的防环机制、严格的区域划分、层次的路由分级、科学的生成树算法等特性使其快速地从各类协...开放式最短路径优先协议(Open Shortest Path First,OSPF)是一种基于链路状态的内部网关协议,其自身广泛的适应范围、较强的快速收敛能力、成熟的防环机制、严格的区域划分、层次的路由分级、科学的生成树算法等特性使其快速地从各类协议中脱颖而出,与中间系统到中间系统(Intermediate System to Intermediate System,ISIS)共同成为内部网关协议的主流。OSPF协议主要是通过发送组播报文、建立邻接关系、泛洪链路状态通告(Line State Advertisement,LSA)、计算路由并转发的方式,实现自治域内路由的交换与转发。基于此,主要对OSPF网络中几种常见特性进行探究。展开更多
文摘In this paper, the open queueing network model is proposed for solving the problem of public transportation in cities. The vertices of the networks(i.e., the bus stops) are determined by means of the fuzzy clustering method. The arcs (i.e., the paths of the public transportation) can be set up by using the shortest path model in the time sense or the 0 1 integer programming method.Applying the statistics method, we can calculate the parameters(such as the passenger flow's distribution, passenger flow's transition probability, mean waiting time for the bus etc. ) of the public transportation network. In this paper, we suggest to divide the network into two or three stages to implement the public transportation system in the form of ``frog jumping' fast transfer and ``permeation' fast dispersion.Combining the computer simulation and the evaluation of the achievement and effect of public transportation system, we modify the model so as to solve the public transportation problem better.
文摘OSPF（Open Shortest Path First Protocol）协议是目前Internet上广泛使用的自治系统内部交换路由信息的动态路由协议。文章介绍了在清华大学研制的国产高性能路由器中分布式路由协议OSPF－2的具体实现。为了实现这一复杂的动态协议，文章提出了基于事件驱动的虚拟多任务机制的设计和实现方法。这种机制能够有效支持复杂系统的分解，在实时性要求不高的前提下提供一种简便有效的并行机制，方便基于状态机的软件实现，提高了软件的可移植性。该方法对于其它的Internet高层协议的设计和实现也有一定的参考价值。
文摘开放式最短路径优先协议(Open Shortest Path First,OSPF)是一种基于链路状态的内部网关协议,其自身广泛的适应范围、较强的快速收敛能力、成熟的防环机制、严格的区域划分、层次的路由分级、科学的生成树算法等特性使其快速地从各类协议中脱颖而出,与中间系统到中间系统(Intermediate System to Intermediate System,ISIS)共同成为内部网关协议的主流。OSPF协议主要是通过发送组播报文、建立邻接关系、泛洪链路状态通告(Line State Advertisement,LSA)、计算路由并转发的方式,实现自治域内路由的交换与转发。基于此,主要对OSPF网络中几种常见特性进行探究。
