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排序方式: 共有133条查询结果,搜索用时 15 毫秒
51.
一种基于信任模型的安全度量及安全路由算法设计 总被引:1,自引:0,他引:1
针对网络路由的攻击普遍且后果严重。目前的研究大多是采用数字签名,消息验证和入侵检测等机制来提高路由控制信息的安全,基本没有考虑机密应用数据的路由安全问题。该文通过分析通信实体的安全机制和安全威胁来测量链路和节点的信任度,建立节点间的信任关系,并基于该信任模型定义和量化一种新的安全度量SM(Security Metric),提出以SM为选路标准的安全路由算法SMRA(Security Metric based Routing Algorithm)。仿真表明,网络存在攻击时,SMRA算法比OSPF算法有更好的包传输率和路由安全性能。 相似文献
52.
53.
In this paper we study feedback stabilization for distributed semilinear control systems . Here, A is the infinitesimal generator of a linear C
0
-semigroup of contractions on a real Hilbert space H and is a nonlinear operator on H into itself. A sufficient ad-condition is provided for strong feedback stabilization. The result is illustrated by means
of partial differential systems.
Accepted 31 July 1996 相似文献
54.
介绍了SM2527-41L线性MMDS固态功率放大器,其性能类似于100W的补偿型HPA,而功耗更低、体积更小。 相似文献
55.
《Digital Communications & Networks》2019,5(3):183-188
Quadrature Spatial Modulation (QSM) is a high spectral efficiency Multiple-Input Multiple Output (MIMO) technique used to improve the spectral efficiency of wireless communication systems. The main concept of QSM is to extend the spatial constellation of the conventional Spatial Modulation (SM) in both the in-phase and quadrature components of the data symbol. In this paper, because QSM-based on Interleaving Division Multiplexing (IDM) has not been introduced in the literature as a multiple antenna system, we introduced a novel scheme, called QSM system based on Interleaving Division Multiplexing (QSM-IDM). The antenna sets are also applied to a spreader, before being used to assign an antenna number for information transmission. Analysis and simulations for a flat fading channel show that the proposed QSM-IDM method significantly outperforms the original QSM system with the same data rate, while maintaining a relatively acceptable complexity. The obtained simulation results show that the conducted analysis yields significant improvements for the accuracy of the proposed scheme, with satisfactory complexity. 相似文献
56.
Sangchoon Kim 《ETRI Journal》2016,38(4):606-611
This paper presents antenna selection schemes for recently proposed quadrature spatial modulation (QSM) systems. The antenna selection strategy is based on Euclidean distance optimized antenna selection (EDAS). The symbol error rate (SER) performance of these schemes is compared with that of the corresponding algorithm associated with spatial modulation (SM) systems. It is shown through simulations that QSM systems using EDAS offer significant improvement in terms of SER performance over SM systems with EDAS. Their SER performance gains are seen to be about 2 dB–4 dB in Es/N0 values. 相似文献
57.
本文主要介绍了西门子传动SMl50在宝钢薄带连铸新增试验轧机项目中的应用。文中介绍了项目的概况、控制系统配置和设备选型依据,并着重介绍了SMl50软硬件配置、主要功能以及在本项目中发挥的重要作用。 相似文献
58.
Yung‐Ping Tu Wen‐Hsien Fang Yie‐Tarng Chen 《Wireless Communications and Mobile Computing》2012,12(9):767-781
This paper presents a new space–time two‐stage receiver with the assistance of soft information for the Alamouti space–time block code (STBC) and spatially multiplexing (SM) combined multiple‐input multiple‐output (MIMO) systems, which possess both the advantages of high diversity gain and high data rates to entail the next generation wireless communication systems. The first stage of the receiver, utilizing the inherent structure of the STBC, consists of a bank of soft generalized sidelobe canceller (GSC)‐based detectors, each for every STBC block, and intends to yield a more precise initial estimate of the transmitted symbols. In the second stage, the groupwise detection is conducted successively by using the matched filters (MFs) to simultaneously detect the two consecutive symbols in one STBC block with the removal of the soft interferences in between. Since the interferences have been faithfully reproduced and thoroughly annihilated, the new receiver can yield accurate symbol detection even with simple MFs. Moreover, some extreme cases regarding the soft information employed in the new receiver and its extension to the multiuser (MU) MIMO downlink are addressed as well. Conducted simulations show that the developed receiver, with modest computational load, can provide superior performance compared with pervious works, especially in the MU MIMO downlink. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
59.
60.
M. Pierini 《Progress in Particle and Nuclear Physics》2009,62(1):1-47
The vast amount of flavor physics data available to date allows probing the presence of physics beyond the standard model through precision measurements of CP violating and CP conserving processes involving B, D, and K mesons. The information extracted from these measurements allows the characterization of physics beyond the standard model in a complementary way with respect to the direct searches at the Tevatron and the LHC. We review the status of the search for new physics with flavor-related observables. We discuss the status of the unitarity triangle analysis beyond the standard model: the inclusion of the recent measurements of Bs decays from the Tevatron experiments point to a discrepancy from the standard model expectation. In addition, we discuss the impact of O(ΛQCD/mb) corrections to the perturbative calculation of charmless hadronic B decays. These corrections can explain the puzzling values of direct CP asymmetries in B→Kπ decays within the standard model. These corrections cannot explain values of sin2β lower than the standard model value, as observed in b→s penguin decays. We conclude with the perspectives of the next generation of flavor-physics experiments, the precision they can reach and their phenomenological impact. 相似文献