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11.
Convergence, interoperability, and mobility are the major advances and factors of differentiation in 3G networks, while the inherent IP support will boost new personalized multimedia services. However, the deployment of a global all-IP wireless/mobile network is not a straightforward decision. A phased approach, focusing on "hot-spot" locations with complementary wireless technologies, seems to be one of the most realistic alternatives. This article discusses a new architecture called unified wireless access that focuses on public "hot-spots." The major algorithms of UniWA are analyzed and evaluated, while the gain is presented and illustrated in selected graphs  相似文献   
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Global roaming in next-generation networks   总被引:5,自引:0,他引:5  
Next-generation mobile/wireless networks are already under preliminary deployment. Mobile/wireless all-IP networks are expected to provide a substantially wider and enhanced range of services. However, an evolutionary rather than revolutionary approach to the deployment of a global all-IP wireless/mobile network is expected. To support global roaming, next-generation networks will require the integration and interoperation of mobility management processes under a worldwide wireless communications infrastructure. In this article global roaming is addressed as one of the main issues of next-generation mobile networks. Apart from the physical layer connectivity and radio spectrum allocation plans, mobility in a hierarchical structured scheme is discussed. An all-IP wireless/mobile network combined with inherited mobility schemes of each network layer and Mobile IP extensions is proposed. In this respect the mobility management mechanisms in WLAN, cellular, and satellite networks are analyzed, and an all-IP architecture is described and an enhanced roaming scenario presented  相似文献   
14.
Connecting each house to a broadband access network represents an unprecedented opportunity to offer added-value services and broadband Internet access to residential users and expand the customer base beyond the corporate environment. Home networks, however, may be the last barrier to end-to-end multimedia service provisioning. Although a large number of houses have PCs, modems or multimedia network-enabled appliances, the majority are not equipped to support their interconnection, and most consumers are unwilling or cannot afford large-scale home rewiring. This paper reviews the available home-networking technologies and provides a comparison of the competing broadband in-home technologies. The focus is on technologies that do not require rewiring the home, either reusing the existing wiring or using wireless technology. The paper also discusses the residential gateway (RG) initiative, which provides a single point of convergence between the in-home and the access networks  相似文献   
15.
The Internet is incontrovertibly a great success that has changed our social and economic world. Today, over one billion users access the Internet on regular basis, more than 100 million users have downloaded at least one (multi) media file, and over 47 million of them do so regularly, searching in more than 160 exabytes of content. The content is expected to rise to more than 990 exabytes before 2012, fueled mainly by the users themselves [1]. It is envisaged that in the near- to mid-term future, mobile Internet will provide the means to share and distribute (new) multimedia content and services with superior quality and striking flexibility, in a trusted and personalized way, improving citizens? quality of life, working conditions, edutainment, and safety.  相似文献   
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The range of applications of wireless sensor networks is so wide that it tends to invade our every day life. In the future, a sensor network will survey our health, our home, the roads we follow, the office or the industry we work in or even the aircrafts we use, in an attempt to enhance our safety. However, the wireless sensor networks themselves are prone to security attacks. The list of security attacks, although already very long, continues to augment impeding the expansion of these networks. The trust management schemes consist of a powerful tool for the detection of unexpected node behaviours (either faulty or malicious). Once misbehaving nodes are detected, their neighbours can use this information to avoid cooperating with them, either for data forwarding, data aggregation or any other cooperative function. A variety of trust models which follow different directions regarding the distribution of measurement functionality, the monitored behaviours and the way measurements are used to calculate/define the node's trustworthiness has been presented in the literature. In this paper, we survey trust models in an attempt to explore the interplay among the implementation requirements, the resource consumption and the achieved security. Our goal is to draw guidelines for the design of deployable trust model designs with respect to the available node and network capabilities and application peculiarities. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
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The usability of wireless sensor networks in modern applications requires the fulfillment of dynamic Quality of Service (QoS) requirements that can only be met in a reactive manner by the introduction of composite routing metrics, capturing several distinct network characteristics. However, combining routing metrics is neither a trivial nor an arbitrary task, given the routing protocol requirements and routing metrics properties. In this paper, the theoretical framework of routing algebra formalism is adopted and extended to incorporate single or composite routing metrics, because the satisfaction of routing algebra properties ensures convergence, optimality, and loop‐freeness. Moreover, packet forwarding indication is defined as a new trust metric for systems (a) with or (b) without network retransmissions to avoid forwarding attacks, while a novel composite routing metric is presented, combining link reliability and trust‐awareness in an additive manner, fulfilling the theoretical requirements. Finally, this composite metric is applied to the Routing Protocol for Low Power and Lossy Networks via simulations, which verify its efficiency in several scenarios, including the comparison between lexical and additive metric composition approaches. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
18.
(R)evolution toward 4G mobile communication systems   总被引:1,自引:0,他引:1  
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19.
Internet is the most important information exchange means nowadays and has become the core communication environment, not only for business relations, but also for social and human interaction. Yet, the immense success of Internet has created even higher hopes and expectations for new immersive and real-time applications and services. However, there are no guarantees that the current Internet will be able to support them. To face the new requirements coming from these new applications and services, several architectural approaches have been proposed. Evolutionary and clean-slate approaches, based on content-centric architectures, have been proposed for meeting new requirements regarding media. This paper highlights the main architectural functions and presents a revolutionary protocol stack and a holistic architectural approach that targets Future Media Internet (FMI). Among the architectural functions and the holistic approach, the paper presents solutions to overcome the current content delivery limitations, moving intelligence in the network and converting it into a content oriented/centric network, that goes well beyond current CDNs; supporting the functionalities for producing, publishing, caching, finding and consuming content; and a novel Future Media Internet protocol stack and network architecture.  相似文献   
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Widespread and affordable mobile broadband access opens up opportunities for delivery of new streaming services everywhere and anytime. However, what is expected to fundamentally change the way how people use the network is the ability to produce, and seamlessly deliver and share their own multimedia content. In this paper we describe the content distribution and adaptation architecture that we have implemented and tested, the results utilising new coding formats of video coding (e.g. SVC, MVC) and new methods for increasing the robustness of video delivery.  相似文献   
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