计算机中英文新技术词汇对照

计算机中英文新技术词汇对照ＡＣＡ（ＡｄａｐｔｉｖｅＣｏｍｐｏｎｅｎｔＡｒｃｈｉｔｅｃｔｕｒｅ）适应性组件体系结构ＤＯＣＡ（ＤｉｓｔｒｉｂｕｔｅｄＯｂｊｅｃｔＣｏｍｐｕｔｉｎｇＡｒｃｈｉｔｅｃｔｕｒｅ）分布式对象计算体系结构ＤＳＡ（ＤｙｎａｍｉｃＳｃａ...     

塑模CAD建库的数据分析及程序实现

本文给出了美国ＡｄｖａｎｃｅｄＣＡＥＴｅｃｈｎｅｌｅｇｙＩｎｃ。注塑模设计与分析软件Ｃ－ＦＬＯＷ，Ｃ－ＣＯＯＬ，Ｃ－ＰＡＣＫ中塑料材料库的建立方法，同时给出测量原理以及主要参数的计算方法，供有关技术人员参考使用。     

优化双极器件的改善BiCMOS电路延迟的CAD方法

优化双极器件的改善ＢｉＣＭＯＳ电路延迟的ＣＡＤ方法＝ＡＣＡＤｐｒｏｃｅｄｕｒｅｆｏｒｏｐｔｉｍｌｚｉｎｇｂｉｐｏｌａｒｄｅｖｉｃｅｓｒｅｌａｔｉｖｅｔｏＢｉＣＭＯＳｃｉｒｃｕｉｔｄｅｌａｙ［刊．英］／Ｄｅｓ－ｏｕｋｌ．Ａ，Ｓ．…ＩＥＥＥＴｒａｎｓ．Ｃ...     

Theoretical Analysis and Calculation for Rotatory Optic Fiber

ＴｈｅｏｒｅｔｉｃａｌＡｎａｌｙｓｉｓａｎｄＣａｌｃｕｌａｔｉｏｎｆｏｒＲｏｔａｔｏｒｙＯｐｔｉｃＦｉｂｅｒ①②ＢＡＯＺｈｅｎｗｕ，ＺＨＡＮＧＹａｑｉ（ＥｌｅｃｔｒｏｎｉｃＩｎｆｏｒｍａｔｉｏｎＥｎｇｉｎｅｅｒｉｎｇＣｏｌｅｇｅ，ＴｉａｎｊｉｎＵｎｉ...     

Preparation of Organic Semiconductor PTCDA and Studies on Its Crystal Structure and the Absorption Spectrum

ＰｒｅｐａｒａｔｉｏｎｏｆＯｒｇａｎｉｃＳｅｍｉｃｏｎｄｕｃｔｏｒＰＴＣＤＡａｎｄＳｔｕｄｉｅｓｏｎＩｔｓＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅａｎｄｔｈｅＡｂｓｏｒｐｔｉｏｎＳｐｅｃｔｒｕｍ①②ＺＨＡＮＧＦｕｊｉａ，ＳＨＡＯＪｉａｆｅｎｇ，ＺＨＡＮＧＤｅ...     

TDMAX和FASTCOM──用于国内和企业通信的新型卫星系统

ＴＤＭＡＸ和ＦＡＳＴＣＯＭ──用于国内和企业通信的新型卫星系统Ｊ．Ｃｏｕｅｔ等“ＴＤＭＡＸａｎｄＦＡＳＴＣＯＭ－ＮｅｗＳａｔｅｌｌｉｔｅＳｙｓｔｅｍｓｆｏｒＤｏｍｅｓｔｉｃａｎｄＣｏｒｐｏｒａｔｅＣｏｍｍｕｎｉｃｃａｔｉｏｎｓ，”Ｅｌｅｃｔｒｉｃａｌ...     

Spatial Light Modulator with BSO Crystal and Its Application in Holography

ＳｐａｔｉａｌＬｉｇｈｔＭｏｄｕｌａｔｏｒｗｉｔｈＢＳＯＣｒｙｓｔａｌａｎｄＩｔｓＡｐｐｌｉｃａｔｉｏｎｉｎＨｏｌｏｇｒａｐｈｙ①ＷＡＮＧＷｅｎｓｈｅｎｇ（ＣｈａｎｇｃｈｕｎＣｏｌｅｇｅｏｆＯｐｔｉｃｓａｎｄＦｉｎｅＭｅｃｈａｎｉｃｓ，Ｃｈａｎｇｃｈ...     

The Application of ODE Method in MOP

ＴｈｅＡｐｐｌｉｃａｔｉｏｎｏｆＯＤＥＭｅｔｈｏｄｉｎＭＯＰ￥ＺｈｏｕＺｏｎｇｆａｎｇ（ＣｈｏｎｇｑｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＰｏｓｔｓａｎｄＴｅｌｅｃｏｍｍｕｎｉｃａｔｉｏｎ，Ｃｈｏｎｇｑｉｎｇ６３００６５，Ｐ．Ｒ．Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ...     

An Encoder/Decoder Scheme of OCDMA Based on Waveguide

1　ＩｎｔｒｏｄｕｃｔｉｏｎＯｐｔｉｃａｌＣｏｄｅＤｉｖｉｓｉｏｎＭｕｌｔｉｐｌｅＡｃｃｅｓｓ(ＯＣＤ ＭＡ)ｓｙｓｔｅｍｓｈａｖｅｂｅｅｎｉｎｖｅｓｔｉｇａｔｅｄ[1 ] .Ｍａｎｙｅｎ ｃｏｄｅｒｓ/ｄｅｃｏｄｅｒｓｈａｖｅｂｅｅｎ ｐｒｏｐｏｓｅｄ ,ｆｏｒｅｘａｍｐｌｅ,ｏｐｔｉｃａｌｆｉｂｅｒｄｅｌａｙ ｌｉｎｅｓ[2 ] .Ｉｎｔｈｉｓｐａｐｅｒ,ｗｅｅｍｐｌｏｙｔｈｅｌｏｗ ｗｅｉｇｈｔＯｐｔｉｃａｌＯｒｔｈｏｇｏｎａｌＣｏｄｅ(ＯＯＣ ｓ) [3～5] ｗｉｔｈｔｈｅｌｅｎｇｔｈＭａｎｄｔｈｅｗｅｉｇｈｔΩａｓｏ…     

An Achievable Rate Region for the Asynchronous Multiple Access Channel with Feedback

1　ＩｎｔｒｏｄｕｃｔｉｏｎＧＡＡＲＤＥＲａｎｄＷＯＬＦ[1 ] ａｓｗｅｌｌａｓＣｏｖｅｒａｎｄＬｅｕｎｇｈａｖｅｄｅｍｏｎｓｔｒａｔｅｄｔｈａｔｔｈｅｃａｐａｃｉｔｙｒｅｇｉｏｎｏｆａｄ .ｍ .ＭｕｌｔｉｐｌｅＡｃｃｅｓｓＣｈａｎｎｅｌ(ＭＡＣ)ｃａｎｂｅｉｎ     

Traffic performance analysis of handover in GMPCS systems

This paper presents an analysis of handover process and its effect on the traffic performance in global mobile personal communications by satellite (GMPCS) systems. With the nongeostationary satellite used for the system, the handover scheme needs to be applied to make calls completed without any interruption. An analytical model is developed for the analysis of the handover process. We derive the mean number of handovers and handover delay with various satellite antenna patterns and different settings of handover parameter. A suitable traffic model of the whole system is also derived after due considerations of the handover process. The system performance measures include new call blocking probability, call dropping probability, and mean number of handovers per call. A computer simulation is developed and used. We also analyze the system performance with a number of handover priority schemes applied. Based on the study results, the handover parameters are selected to maximize the traffic performance. It is shown that we can improve the overall traffic performance of GMPCS system by setting handover parameters properly and using the handover priority scheme     

A model for the handover traffic in low earth-orbiting (LEO) satellite networks for personal communications

The spectacular growth of cellular telephone networks has demonstrated the demand for personal communications. Communication systems based on low earth orbit (LEO) constellations of satellites seem to be an adequate approach to achieve a world-wide network. When defining the capacity in terms of satellite circuits, the network designer has to take into account the handover traffic. Unfortunately, in a LEO communication network where handover is most often due to the network nodes motion, handover traffic models for terrestrial cellular networks cannot be used. Hence specific models must be developed. This paper proposes an analytical model for the handover in LEO satellite networks. This model is applied to different network configurations and compared to discrete-time simulations. Simulation results agree with those obtained from the analytical model.     

Performance analysis of handover delay and buffer capacity in mobile OpenFlow‐based networks

Software‐defined networking (SDN) is a network concept that brings significant benefits for the mobile cellular operators. In an SDN‐based core network, the average service time of an OpenFlow switch is highly influenced by the total capacity and type of the output buffer, which is used for temporary storage of the incoming packets. In this work, the main goal is to model the handover delay due to the exchange of OpenFlow‐related messages in mobile SDN networks. The handover delay is defined as the overall delay experienced by the mobile node within the handover procedure, when reestablishing an ongoing session from the switch in the source eNodeB to the switch in the destination eNodeB. We propose a new analytical model, and we compare two systems with different SDN switch designs that model a continuous time Markov process by using quasi‐birth–death processes: (1) single shared buffer without priority (model SFB), used for all output ports for both control and user traffic, and (2) two isolated buffers with priority (model priority finite buffering [PFB]), one for control and the other for user plane traffic, where the control traffic is always prioritized. The two proposed systems are compared in terms of total handover delay and minimal buffer capacity needed to satisfy a certain packet error ratio imposed by the link. The mathematical modeling is verified via extensive simulations. In terms of handover delay, the results show that the model PFB outperforms the model SFB, especially for networks with high number of users and high probability of packet‐in messages. As for the buffer dimensioning analysis, for lower arrival rates, low number of users, and low probability of packet‐in messages, the model SFB has the advantage of requiring a smaller buffer size.     

Analysis of secure handover for IEEE 802.1x-based wireless ad hoc networks

The handover procedure in secure communication wireless networks is an extremely time-consuming phase, and it represents a critical issue in relation to the time constraints required by certain real-time traffic applications. In particular, in the case of the IEEE 802.1X model, most of the time required for a handover is used for packet exchanges that are required for authentication protocols, such as Extensible Authentication Protocol Transport Layer Security (EAP-TLS), that require an eight-way handshake. Designing secure re-authentication protocols to reduce the number of packets required during a handover is an open issue that is gaining interest with the advent of a pervasive model of networking that requires realtime traffic and mobility. This article presents the 802.1X model and evaluates its application to ad hoc networks based on IEEE 802.11 i or IEEE 802.1 be standards, focusing on the problems that must be evaluated when designing handover procedures, and suggesting guidelines for securing handover procedures. It also presents a novel protocol to perform secure handovers that is respectful of the previous analysis and that has been implemented in a mesh environment.     

The frequency of CFVD speed report for highway traffic

The control signals of cellular networks have been used to infer the traffic conditions of the road network. In particular, consecutive handover events are being used to estimate the traffic speed. During traffic congestion, consecutive handover events may be rare because vehicles move slowly, and thus very few or no speed reports would be generated from the congested area.However, the traffic speed report rate during traffic congestion has not been investigated in the literature. In this paper, we present an analytic model to estimate the speed report rate from cellular network signaling in steady traffic conditions, that is, the traffic speed and flow are assumed constant. Real field trial data were used to validate our analytic model. In addition, computer simulations were conducted to study how speed reports are generated in dynamic traffic conditions when traffic speed and flow change rapidly. Our study indicates that in a typical cell of length 1.5 km with a typical expected call holding time of 1 min, no speed report was generated from a congested three‐lane highway. Our study demonstrates that the lack of speed reports from consecutive handover events during rush hours indicates severe traffic congestion, and new methods that can estimate traffic speed from cellular network data during severe traffic congestion need to be developed. Copyright © 2013 John Wiley & Sons, Ltd.     

IMS域的切换研究

基于IMS(IP Multimedia Subsystem)域的通信中由于切换层次的增多导致切换时间的增加,从而使得服务的中断时间加长,这影响了移动中应用的服务质量。在UMTS(Universal Mobile Telecommunication System)R6规范中的切换流程中,跨网络切换采用SGSN(Serving GPRS Support Node)之间的切换而GGSN(Gateway GPRS Support Node)不变,这会导致数据流在IP(Internet Protocol)网络中的迂回,并且多条信令跨网络传输影响了切换的速度,增加了网络流量和端到端延时。该文在现有切换流程上提出了跨GGSN的切换流程,缩短了媒体流在切换过程中的中断时间,并减少了漫游状态下的端到端媒体流引起的网络流量和端到端的数据延迟。     

Adaptive distribution‐based handover scheme for cellular communication networks

In this paper, we propose a new Generalized Distribution‐Based Handover (DBHO) to deal with the inefficient utilization of spectral resources due to the non‐uniform cell loads. The DBHO scheme is different from the existing adaptive schemes since it uses a new criterion to initiate handover when moving from/to a congested cell. Two risk factors are used to dynamically change handover boundaries according to the distribution of traffic loads. This controls the handover initiation process such that a user in a congested cell that is moving to a free cell is allowed to initiate a handover to a new cell earlier, as long as the signal received from the target cell is higher than a certain threshold. While delaying the handover initiation process for a user moving in the opposite direction, as long as the signal received from the serving cell is not lower than a certain threshold. Our results show a substantial reduction in the handover and call dropouts rates. Our scheme is complementary to the existing adaptive schemes proposed in the literature. The proposed scheme also gives cellular system designers a new tool to optimize the overall network performance by initiating handovers based on the traffic intensities. Frequent handovers increase the load on switching networks, which consequently degrades the Quality of Service (QoS). Existing handover schemes usually use parameters such as the received signal strength for initiating a handover with some additional measurements to reduce unnecessary handovers and call dropouts. These schemes perform well when cell loads are somewhat evenly distributed, but fail to account for nonuniform traffic, as is often the case in microcells. Hence, it is desirable to design efficient handover schemes to avoid unnecessary handovers, reduce call dropouts and yet dynamically adapt to the variation of traffic among cells. In this paper, we present a new adaptive handover scheme that dynamically changes the handover boundaries to balance cell loads and to effectively reduce the average number of handovers. Copyright © 2004 John Wiley & Sons, Ltd.     

Mechanisms and hierarchical topology for fast handover in wireless IP networks

We propose a mechanism to perform fast handover in IP-based wireless networks for real-time applications such as Internet telephony and videoconferencing. Our proposal is designed to reestablish the communication session traffic flow quickly and to minimize the service disruption delay that occurs during mobile IP handover. In this scheme, we propose two different mechanisms to handle micromobility and inter-subdomain mobility, respectively. Micromobility handover handles movements within the same subdomain. Inter-subdomain handover supports handovers between two adjacent subdomains. The reason for having several subdomains is to deploy the network over a wider area to keep the mobile user in the same network for as long as possible. The novelty of the scheme is to retransmit the buffered packets during micromobility handover and to use multicasting to reestablish traffic flow during inter-subdomain movement. The entire scheme is performed within a hierarchical topology based on next-generation IP networks. We analyze both micromobility and inter-subdomain mobility handovers, and display simulation results for both voice and video over IP for micromobility handover.     

C+W网络无缝切换研究

对基于客户端实现的cdma2000 Ev-Do+Wi-Fi无缝切换功能进行研究,并对切换原理、切换流程、切换算法、策略及通过现网测试评估分流Ev-Do效果等方面进行描述。Ev-Do和Wi-Fi网络无缝切换功能,为CDMA用户的业务流由Wi-Fi网络分担给出了技术解决方法,对C+W分流工作,具有积极的现实意义。     

Enhancing inter-PMIPv6-domain for superior handover performance across IP-based wireless domain networks

As a network-based localized mobility management protocol, Proxy Mobile IPv6 (PMIPv6) enables a Mobile Host (MH) to roam within a localized domain without MH intervention in the mobility-related signalling. However, the PMIPv6 maintains MH mobility support in a restriction domain. Therefore, whenever the MH roams away from the PMIPv6 domain, its reachability status will be broken-down causing high handover latency and inevitable traffic loss for its communication session. This article proposes a proactive mechanism to mange the MH handover and maintain its data session continually across inter-PMIPv6-domains. The proposed mechanism introduces an intermediate global mobility anchor entity, called, which is responsible to coordinate MH handover as well as redirect its traffic across inter-PMIPv6-domains. Through various simulation evaluations, via ns-2, several experiments were conducted, revealing numerous results that verify the proposed mechanism superior performance over the conventional inter-PMIPv6-domain handover schemes in terms of handover latency, achieved throughput, protocol signalling cost and end-to-end traffic delivery latency.