A PARALLEL SWITCH FABRIC BASED ON CROSSBAR

With the increase of link rate, the arbitrator of centralized switch fabric becomes too complicated to implement. A parallel switch fabric based on crossbar, named as PSFBC （Parallel Switch Fabric Based on Crossbar）, has been proposed in this paper. PSFBC is composed of k switches whose rate is 1/k of link, these switches exchange cells in parallel; this increases the arbitrator＇s period and make it easy to implement. Load is evenly distributed to each switch with FCFS （First Come First Serve） rule, it can keep the order of cells in one stream. A multi-class queue scheduling policy is used in PSFBC to ensure the quality of realtime streams. Experiments show that the load on each switch in PSFBC is well balanced, its average delay of cells is little and its performance is very close to centralized switch; and with the increase of number of parallel switches, the loss of PSFBC＇s performance keeps very small, it becomes easier to implement.     

多跨连续张弦梁钢管桁架施工技术

张弦梁作为一种混合结构形式在铁路站台雨棚工程结构中得到越来越多的应用.由于张弦梁钢管桁架有着其结构的特殊性,需进行施工阶段的验算,本文以天津站雨棚工程主体结构施工为例,介绍了多跨连续张弦梁钢管桁架结构施工技术.     

跨多条铁路门式棚架梁吊装施工技术

京沪高速铁路城际联络线南仓特大桥125m钢桁梁上跨4条铁路既有线,吊装施工采用钢桁梁门式棚架梁吊装施工技术。论述要点前的准备工作,吊车站位布置及分工,拆铺,临时道口、垫梁吊装、工字钢吊装和贝雷梁吊装施工,提出施工技术方案和注意事项。     

FAULT IDENTIFICATION IN HETEROGENEOUS NETWORKS USING TIME SERIES ANALYSIS

Fault management is crucial to provide quality of service grantees for the future networks, and fault identification is an essential part of it. A novel fault identification algorithm is proposed in this paper, which focuses on the anomaly detection of network traffic. Since the fault identification has been achieved using statistical information in management information base, the algorithm is compatible with the existing simple network management protocol framework. The network traffic time series is verified to be non-stationary. By fitting the adaptive autoregressive model, the series is transformed into a multidimensional vector. The training samples and identifiers are acquired from the network simulation. A k-nearest neighbor classifier identifies the system faults after being trained. The experiment results are consistent with the given fault scenarios, Which prove the accuracy of the algorithm. The identification errors are discussed to illustrate that the novel fault identification algorithm is adaptive in the fault scenarios with network traffic change.     

TSP探测技术在铜锣山隧道塌方中的应用

利用TSP对四川铜锣山隧道塌方的规模、塌方上方空洞大小等进行较为成功的探测,为施工单位提供了较为准确的资料,得到了建设单位的好评。     

高架斜拉桥跨越铁路转体施工技术

介绍高架转体斜拉桥跨越铁路施工技术 ,其中包括转体动力计算、转体施工方法、转体施工控制措施等     

点上更换交叉渡线施工技术

从保证运营和施工两方面的效率和安全出发对京九线更换提速交叉渡线的施工方法进行了探讨,通过采用分4组单开预铺拨入方案施工,效果良好.     

DYNAMIC REQUEST DISPATCHING ALGORITHM FOR WEB SERVER CLUSTER

Distributed architectures support increased load on popular web sites by dispatching client requests transparently among multiple servers in a cluster. Packet Single-Rewriting technology and client address hashing algorithm in ONE-IP technology which can ensure application-session-keep have been analyzed, an improved request dispatching algorithm which is simple, effective and supports dynamic load balance has been proposed. In this algorithm, dispatcher evaluates which server node will process request by applying a hash function to the client IP address and comparing the result with its assigned identifier subset; it adjusts the size of the subset according to the performance and current load of each server, so as to utilize all servers＇ resource effectively. Simulation shows that the improved algorithm has better performance than the original one.     

既有线人工换枕施工及其安全控制

根据京秦客运通道提速改造工程中大规模人工换枕的施工情况 ,结合采取的施工方法 ,提出了施工安全控制措施 ,为我国运营线上的类似施工提供了经验借鉴。     

石景山南站跨越铁路高架斜拉桥转体施工技术

介绍跨越铁路的高架斜拉桥转体施工技术,包括转体动力计算、转体施工方法、施工控制措施及安全防护措施等.