QoS-Guided Bandwidth Management in Differentiated Time Scales

This paper presents an integrated approach to QoS-guided network bandwidth allocation where each traffic flow requires a sufficient bandwidth allocation to support its mean traffic rate and to meet a delay requirement. Under the assumption that the peak rate of each traffic flow is decreasing with the time interval within which the rate is measured, we derive an analytical relationship between the delay bound and the bandwidth requirement for each individual flow. Then, based on a Gaussian aggregate traffic model, we show that two key controllable parameters, the coefficient of variation and the provision for variation for the aggregate traffic flow, determine all three fundamental QoS attributes (throughput, delay, and loss). We illustrate by examples that these results can be used to design admission policies. We demonstrate also quantitatively a remarkable QoS advantage of larger channel bandwidth in a statistical multiplexing environment. The analytical contributions are expected to be generally useful in QoS-guided bandwidth management in broadband networks.     

On upper bounds of bandwidths of trees

ＯＮＵＰＰＥＲＢＯＵＮＤＳＯＦＢＡＮＤＷＩＤＴＨＳＯＦＴＲＥＥＳＷＡＮＧＪＩＡＮＦＡＮＧ（王建方）（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓ,ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ,Ｂｅｉｊｉｎｇ１０００８０,Ｃｈｉ...     

The bandwidth of the complement of A K-TREE

The paper proves that it G is a k-tree, then the bandwidth B(^-G) of the complement ^-G of G given byB（^-G）=n-k-1,when G≈Kk-^Kn-k,n-k-2,otherwise.     

Bootstrap choice of tuning parameters

Consider the problem of estimating θ=θ(P) based on datax _n from an unknown distributionP. Given a family of estimatorsT _{n, β} of θ(P), the goal is to choose β among β∈I so that the resulting estimator is as good as possible. Typically, β can be regarded as a tuning or smoothing parameter, and proper choice of β is essential for good performance ofT _{n, β} . In this paper, we discuss the theory of β being chosen by the bootstrap. Specifically, the bootstrap estimate of β, , is chosen to minimize an empirical bootstrap estimate of risk. A general theory is presented to establish the consistency and weak convergence properties of these estimators. Confidence intervals for θ(P) based on , are also asymptotically valid. Several applications of the theory are presented, including optimal choice of trimming proportion, bandwidth selection in density estimation and optimal combinations of estimates.     

Lexicographic maximin optimisation for fair bandwidth allocation in computer networks

This paper addresses the problem of bandwidth allocation in multi-application computer network environments. Allocations are determined from the solution of a multiple objective optimisation problem under network constraints, where the lexicographic maximin criterion is applied to solve the problem and guarantees fairness and efficiency properties to the solution. An algorithm based on a series of maximum concurrent multicommodity flow subproblems is proposed. Numerical results show the advantage of the approach compared to other traditional bandwidth allocation solutions.     

带宽自适应的均值漂移红外目标跟踪算法

当目标尺度发生变化时,传统均值漂移跟踪因窗口尺寸不变导致跟踪目标丢失.为解决该问题,提出一种带宽自适应的均值漂移跟踪算法.该算法在均值漂移框架下提取目标的形状特征,根据目标形状变化自适应的修正核函数带宽,并更新目标模板.实验结果表明,改进算法能很好地适应尺寸变化的目标,能有效提高红外目标的跟踪准确度.     

The bandwidth sum of join and composition of graphs

Given a graph G, a proper labeling f of G is a one-to-one function . The bandwidth sum of a graph G, denoted by B_s(G), is defined by B_s(G)=min∑_uvE(G)|f(u)-f(v)|, where the minimum is taken for all proper labelings f of G. In this paper, we give some results for the bandwidth sum problem for the join of k graphs G₁,G₂,…,G_k, where each G_i is a path, cycle, complete graph, or union of isolated vertices. We also discuss the bandwidth sum for the composition of two graphs G and H, where G and H are path, cycle, or union of isolated vertices.     

A novel method of optimal apodization selection for chirped fiber Bragg gratings

Apodization is a crucial technology for improving the dispersion performance of fiber Bragg gratings (FBGs). In this paper, we focus on how to select an optimal apodization for chirped fiber Bragg gratings and demonstrate a novel apodization selection method capable of choosing the optimal apodization based on the relationship between the bandwidth change and variation in average group delay ripple (GDR). Compared with current approaches, the novel method can select an optimal apodization profile and parameter for FBGs easily and accurately. Two numerical experiments are used to demonstrate the advantages of this method, one exhibits the different performances of five different apodization profiles, the other evaluates the influence of FBG parameters such as grating length, period, chirp, and index change on the apodization performance.     

PI-P控制算法在弱刚度伺服系统中的应用

为了提高伺服系统的带宽,减小重量、体积和成本的增加,提高光电经纬仪的高速、高精度、高稳定性,分析了弱刚度系统的影响机理,采用PI-P无超调控制算法有效抑制了系统振荡特性的发生,在弱刚度系统中实现了较高控制性能,并直接应用于160电影经纬仪的改造中,取得了明显的效果.该方法对同类系统的设计具有重要的应用价值.