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1.
Yoon SH  Lee S 《Water research》2005,39(15):3738-3754
Mathematical models were developed to elucidate the relationships among process control parameters and the effect of these parameters on the performance of anoxic/oxic biological wastewater processes combined with sludge disintegrators (A/O-SD). The model equations were also applied for analyses of activated sludge processes hybrid with sludge disintegrators (AS-SD). Solubilization ratio of sludge in the sludge disintegrator, alpha, hardly affected sludge reduction efficiencies if the biomass was completely destructed to smaller particulates. On the other hand, conversion efficiency of non-biodegradable particulates to biodegradable particulates, beta, significantly affected sludge reduction efficiencies because beta was directly related to the accumulation of non-biodegradable particulates in bioreactors. When 30% of sludge in the oxic tank was disintegrated everyday and beta was 0.5, sludge reduction was expected to be 78% and 69% for the A/O-SD and AS-SD processes, respectively. Under this condition, the sludge disintegration number (SDN), which is the amount of sludge disintegrated divided by the reduced sludge, was calculated to be around 4. Due to the sludge disintegration, live biomass concentration decreased while other non-biodegradable particulates concentration increased. As a consequence, the real F/M ratio was expected to be much higher than the apparent F/M. The effluent COD was maintained almost constant for the range of sludge disintegration rate considered in this study. Nitrogen removal efficiencies of the A/O-SD process was hardly affected by the sludge disintegration until daily sludge disintegration reaches 40% of sludge in the oxic tank. Above this level of sludge disintegration, autotrophic biomass concentration decreases overly and TKN in the effluent increases abruptly in both the A/O-SD and AS-SD processes. Overall, the trends of sludge reduction and effluent quality according to operation parameters matched well with experimental results found in literatures.  相似文献   
2.
针对SDN中控制器系统的单节点故障问题,兼顾系统成本和系统时延,应用N+1冗余备份模型来提高SDN控制器部署的可靠性,并将其抽象为多目标优化问题.同时,提出了一种融合K-means聚类算法和遗传算子的多目标二进制粒子群算法——KMOBPSO算法,以求解SDN控制器高可靠性部署问题的解.仿真结果表明,所提算法具有求解精度高、分布均匀、沿Pareto前沿面覆盖广的特点,能够显著提高SDN中控制器部署的可靠性.  相似文献   
3.
DPI(深度分组检测)设备广泛应用于多种流量和业务分析系统,是完成流量识别和处理的第一步,并已经被广泛部署在现网中.随着DPI技术的不断深入,大量的DPI设备嵌入带来的管理和资本成本上升也日益凸显.在此基础上,阐述了传统DPI设备部署的现状和存在的问题,并基于SDN/NFV技术给出了更先进的嵌入DPI软件的新型智能化网络体系和部署方案.  相似文献   
4.
随着基于服务器虚拟化的云资源池规模的日益扩大,网络成为资源快速交付的瓶颈点,跨数据中心的业务互联互通及可迁移需求也日益突出,云资源池的网络自动化部署技术成为新的研究热点.阐述了基于计算虚拟化技术承载的云资源池内网络自动化部署的概念、应用场景,分析了基于软件定义网络理念的技术架构和关键技术,总结了基于overlay SDN技术的解决方案和部署实践,提出一种可运营的网络自动化部署架构,并对电信运营商开展多业务、多租户承载的云资源池网络自动化部署技术选型给出了建议.  相似文献   
5.
从战略层面对SDN的发展可能给电信业带来的全面、颠覆性变革进行了系统的分析.首先介绍了SDN和NFV的内涵与异同,对电信业与IT业的基本特征做了比较,并分析了SDN前电信业的探索及教训.接下来探讨了现有电信网的基本问题和症结以及发展SDN的主要驱动力.重点阐述了SDN的基本特征和对运营商的5个核心价值及其应用前景.最后论述了发展SDN面临的主要挑战,并简要总结了笔者对于SDN战略层面上的思考要点.  相似文献   
6.
为了实现流表的多元快速查找,OpenFlow交换机一般采用TCAM存储和查找流表,从而带来了扩展性、成本和能耗的问题。尽管可以采取流表压缩、引入RAM存储器等方法,但仍无法彻底解决使用TCAM造成的局限性。针对这个问题提出了源端控制的OpenFlow数据面模型,即SCOF(source-controlled OpenFlow)。它以一种源路由地址—向量地址(VA)作为数据分组的交换标签,VA完全定义了通信路径。SCOF的数据转发设备是向量交换机,它不需要存储和查找流表,只根据VA即可完成数据分组转发。SCOF模型降低了交换机硬件复杂度,简化了流表更新过程,克服了OpenFlow的扩展性问题。  相似文献   
7.
过去30年来,通信产业经历了重大的变革,很大程度上,业务模式从提供有线宽带转变为随时随地提供无缝的互联网和应用接入。这种转变主要得益于半导体技术的持续创新以及光传输和无线传输技术的改进,从而带来了更快、更便宜的带宽。如今,正在迈入由云计算和数以万亿计的全新互联设备所驱动的行业新纪元——万物互联。这就意味着电信运营商如果想在未来取得成功,必须要在业务模式、网络架构和技术方面做出改变。对这些产业趋势进行了分析,剖析了如何实现网络创新,以满足这些新兴要求以及帮助电信运营商实现其业务目标。  相似文献   
8.
随着4G的大规模商用,业界对5G的研究也正在如火如荼地展开.5G不仅将给带宽、速率、智能化和融合性等方面带来一定变化,而且随着5G新的网络架构演进和网络融合技术的发展,其安全性也将发生相应的变化.为此,探讨了5G安全架构、安全关键技术以及5G安全机制的未来研究方向.  相似文献   
9.
The control and data planes are decoupled in software-defined networking(SDN),which enables both planes to evolve independently,and brings about many advantages such as high flexibility,programmability,and rapid implementation of new network protocols.However,in order to improve the scalability of the control plane at present,some control functionalities are added to the data plane,which is probably to impact on the generality of the data plane.The key challenge of adding control functionalities to the data plane is to strike a careful balance between the generality of the data plane and the scalability of the control plane.We propose some basic principles that both control and data planes should comply with,based on the evolutionary trend of SDN.Moreover,we take two approaches for reference according to the principles,viewed from the control messages in OpenFlow-based SDN.Our evaluations demonstrate that the approaches can maintain the generality of the data plane and improve the scalability of the control plane.  相似文献   
10.
Software-Defined Network(SDN)empowers the evolution of Internet with the OpenFlow,Network Virtualization and Service Slicing strategies.With the fast increasing requirements of Mobile Internet services,the Internet and Mobile Networks go to the convergence.Mobile Networks can also get benefits from the SDN evolution to fulfill the Sth Generation(5G) capacity booming.The article implements SDN into Frameless Network Architecture(FNA) for5G Mobile Network evolution with proposed Mobile-oriented OpenFlow Protocol(MOFP).The Control Plane/User Plane(CP/UP)separation and adaptation strategy is proposed to support the User-Centric scenario in FNA.The traditional Base Station is separated with Central Processing Entity(CPE) and Antenna Element(AE) to perform the OpenFlow and Network Virtualization.The AEs are released as new resources for serving users.The mobile-oriented Service Slicing with different Quality of Service(QoS) classification is proposed and Resource Pooling based Virtualized Radio Resource Management(VRRM) is optimized for the Service Slicing strategy with resource-limited feature in Mobile Networks.The capacity gains are provided to show the merits of SDN based FNA.And the MiniNet based Trial Network with Service Slicing is implemented with experimental results.  相似文献   
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