This paper presents a novel approach for checking route oscillation of border gateway protocol（BGP） quickly,by which the privacy of routing policies of autonomous system（AS） can be respected.Firstly,route update chain tag（RUCT） is constructed to track the forwarding of update report,and local routing library is made to record the changing history of update report.Then route oscillation can be identified by analyzing correlative state of RUCT and local routing library.The characteristic of this approach is that an arbitrary AS can check route oscillation alone only by sharing its network ID,which greatly respects the pri-vacy of routing policies for each AS.This paper shows that both looping in RUCT and consecutive positive-negative report in local record are sufficient conditions for route oscillation.Comparative experiments demonstrate the availability and efficiency of the proposed approach.
The detection of sparse signals against background noise is considered. Detecting signals of such kind is difficult since only a small portion of the signal carries information. Prior knowledge is usually assumed to ease detection. In this paper, we consider the general unknown and arbitrary sparse signal detection problem when no prior knowledge is available. Under a Ney- man-Pearson hypothesis-testing framework, a new detection scheme is proposed by combining a generalized likelihood ratio test （GLRT）-Iike test statistic and convex programming methods which directly exploit sparsity in an underdetermined system of linear equations. We characterize large sample behavior of the proposed method by analyzing its asymptotic performance. Specifically, we give the condition for the Chernoff-consistent detection which shows that the proposed method is very sensitive to the norm energy of the sparse signals. Both the false alam rate and the miss rate tend to zero at vanishing signal-to-noise ratio （SNR）, as long as the signal energy grows at least logarithmically with the problem dimension. Next we give a large deviation analysis to characterize the error exponent for the Neyman-Pearson detection. We derive the oracle error exponent assuming signal knowledge. Then we explicitly derive the error exponent of the proposed scheme and compare it with the oracle exponent. We complement our study with numerical experiments, showing that the proposed method performs in the vicinity of the likelihood ratio test （LRT） method in the finite sample scenario and the error probability degrades exponentially with the number of observations.
With the rapid development of air transportation, network service ability has attracted a lot of attention in academe. Aiming to improve the throughput of the air route network （ARN）, we propose an effective local dynamic routing strategy in this paper. Several factors, such as the rout- ing distance, the geographical distance and the real-time local traffic, are taken into consideration. When the ARN is in the normal free-flow state, the proposed strategy can recover the shortest path routing （SPR） strategy. When the ARN undergoes congestion, the proposed strategy changes the paths of flights based on the real-time local traffic information. The throughput of the Chinese air route network （CARN） is evaluated. Results confirm that the proposed strategy can significantly improve the throughput of CARN. Meanwhile, the increase in the average flying distance and time is tiny. Results also indicate the importance of the distance related factors in a routing strategy designed for the ARN.
The protrusion of the planning of numerical intelligent early-warning and tracking system in this study which can ease triggerman's work strength,lay the next generation intelligence supervision system foundation and expand effectively the video resources use etc. In the numerical intelligent early-warning matrix sub-system,the authors have designed a kind dual-core system which includes both ARM and DSP,and designed detailedly traffic dynamics affairs early-warning arithmetic which bases on that system. And then,this system will carry quickly on fixing the right position of license plate,correcting the inclination degree of license plate,and thinning it to get the number of this license and severity grade. Secondly,in the rotated dome camera sub-system,the authors have designed three-dimensional trajectory mathematical model which makes use of a fuzzy PID controller to achieve the high- speed track. At last,Simulation shows that the proposed control method has high profile tracking precision,accuracy and robustness of the disturbance.
介绍了复杂低空环境下的机会信号导航方法,并提出了一种机会信号选择方法,解决了机会导航信号源类型多、数量多难以选择的问题.由于信号源的几何精度因子(GDOP,Geometry Dilution of Precision)越小则定位精度越高,同一区域信号对GDOP影响相似,因此采用聚类的方法选择信号.首先,将各信号间的距离作为相似度测量参数,通过相似性传播聚类算法获得相似类组;然后,依据类组的中心点确定所选类组;最后,从中选择组内的机会信号.经仿真,分析了不同分布的机会信号聚类特点,通过对汶川震区机会信号选择的仿真,验证了相似性传播聚类算法的有效性.另外,该方法在复杂低空飞行应用中将大大提高信号选择的效率.
