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Optimal Throughput-Delay Scaling in Wireless Networks–Part II:Constant-Size Packets
Throughput-Delay Scaling Wireless Networks Constant-Size Packets
2015/8/12
In Part I we characterized the optimal throughput-delay trade-off in static wireless networks as D(n) = Θ(nT(n)), where D(n) and T(n) are the average packet delay and throughput in a network of n node...
Optimal Throughput-Delay Scaling in Wireless Networks–Part I:The Fluid Model
Queueing theory random walks scaling laws throughput scaling throughput-delay trade-off wireless networks
2015/8/12
Gupta and Kumar (2000) introduced a random model to study throughput scaling in a wireless network with static nodes, and showed that the throughput per source-destination pair is Θ 1/√n log n. Gross...
Optimal scaling of a gradient method for distributed resource allocation
Distributed optimization resource allocations weighted gradient methods convergence rates semidefinite programming
2015/8/10
We consider a class of weighted gradient methods for distributed resource allocation over a network. Each node of the network is associated with a local variable and a convex cost function; the sum of...
Curvelets,Multiresolution Representation, and Scaling Laws
Edges Partitioning Subband Filtering Local Fourier Transform Ridge functions Ridgelets Multiscale ridgelets Pyramids
2015/6/17
Curvelets provide a new multiresolution representation with several features that set them apart from existing representations such as wavelets, multiwavelets, steerable pyramids, and so on. They are ...
极坐标格式成像算法(PFA)的实现存在两个问题：去调频后存在残余视频相位(RVP)；极坐标格式转化成直角坐标格式的插值处理运算量大，且插值精度会影响聚焦效果。针对这两个问题，该文提出了一种基于Scaling原理的距离向重采样方法，而方位向则采用Chirp-Z变换，在完成去RVP的同时完全避免了插值。该算法与传统PFA相比，仅仅使用FFT及信号复乘，更利于在硬件上实现，极大节省了计算成本，而且所得图...
Chirp Scaling SAR成象算法及其实现
CS算法 残余相差 硬件实现
2009/9/1
本文完善了Chirp Scaling(CS)SAR成象算法的数学模型,获得了雷达点目标二维频域的精确解析式,并进一步得到该算法存在的残余相差。通过分析CS算法的特点,提出实现该算法的一种硬件结构。
该文研究了基于Chirp Scaling原理实现双基聚束SAR成像的极坐标格式算法(Polar Format Algorithm, PFA)。PFA通过两个一维插值来实现数据的极坐标格式转换，插值计算量较大。该文基于发射信号的线性调频特性，在距离向对极坐标格式数据进行变标处理，仅包含信号复乘和FFT，从而避免了插值运算。文中对于接收Chirp信号和Dechirp信号分别进行了讨论，依照不同流程实现...
A PHRASE-LEVEL PIECEWISE LINEAR SCALING ALGORITHM FOR MELODY MATCH IN QUERY-BY-HUMMING SYSTEMS
Phrase-level Piecewise Linear Scaling Query-by-Humming
2013/6/28
The Query-by-Humming (QBH) system allows users to retrieve songs by singing/humming. In this paper we propose a phrase-level piecewise linear scaling algorithm for melody match. Musical phrase boundar...
针对目前机载侧视合成孔径雷达(SAR)无法对飞行路线正前方进行高分辨率成像的问题，该文研究了一种新型机载前视SAR，分析了前视SAR的工作原理和方位分辨率提高的可行性。基于空间几何模型和回波信号形式，推导并给出了适用于机载前视SAR成像的chirp scaling算法，给出了各相位补偿因子表达式及算法实现步骤。模拟了前视SAR点目标回波数据，并利用该方法对分布于场景中心及边缘的点目标阵进行了成像仿...
该文从SAR回波的二维频谱表达式入手，研究了适合高波段SAR的CS(Chirp Scaling)类算法和一种适合超宽带(Ultra Wideband，UWB)SAR成像的非线性CS算法，通过对算法推导中的近似性分析，重新刻画了SAR成像，即SAR成像是利用回波频谱特性构造频域或时域相位补偿因子的过程，尤其是对UWB SAR回波，相位补偿因子的精确性直接影响着目标聚焦性能。仿真实验表明，补偿三阶以上...
该文在分析机载双站SAR回波模型的基础上，结合常规单站SAR的Chirp scaling成像算法思想，推导出了双站SAR的Chirp scaling成像算法。对双站SAR的Chirp scaling成像算法进行了误差分析。最后通过仿真验证了算法的有效性。
Rate Control for Hierarchical B-picture Coding with Scaling-factors
Rate Control Hierarchical B-picture Coding Scaling-factors
2010/12/17
The coding performance can be further improved when the hierarchical B-picture coding is introduced into H.264/AVC. However, the existing rate control schemes can NOT work efficiently in such new codi...
Adaptive Search Range Scaling for B Pictures Coding
Search Range Scaling B Pictures Coding
2010/12/16
This paper presents a frame-level adaptive search range scaling strategy for B pictures coding for H.264/AVC from the hardware-oriented viewpoint. After studying the relationship between search range ...
New Scaling Technique for Direct Mode Coding in B Pictures
New Scaling Technique Direct Mode Coding B Pictures
2010/12/14
To leave the maximum flexibility in encoder to optimize the trade-off between coding performance and complexity, in video coding standards such as H.264/AVC [1], H.263 [2] and MPEG-4 [3] etc, any numb...