2007 Information Theory and Applications Workshop最新文献_第5页

Throughput Capacity of Hybrid Radio-Frequency and Free-Space-Optical (RF/FSO) Multi-Hop Networks 射频和自由空间光(RF/FSO)混合多跳网络的吞吐量

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357553

Di Wang, A. Abouzeid

{"title":"Throughput Capacity of Hybrid Radio-Frequency and Free-Space-Optical (RF/FSO) Multi-Hop Networks","authors":"Di Wang, A. Abouzeid","doi":"10.1109/ITA.2007.4357553","DOIUrl":"https://doi.org/10.1109/ITA.2007.4357553","url":null,"abstract":"The per-node throughput capacity of hybrid radio frequency and free space optics (RF/FSO) networks is studied and the benefit of using this hybrid network architecture over the pure RF wireless networks is evaluated. The hybrid RF/FSO network consists of an RF ad hoc network of n nodes, m of them (so called super nodes) are equipped with an additional FSO transceiver. Every RF and FSO transceiver is able to transmit at a maximum data rate of W1 and W2 bits/sec, respectively. All the super node are connected by the FSO links and thus can form a stand-alone FSO network. With a minimum transmit power objective, an upper bound on the per node capacity of radic(1/n log n) + c2W2 radic(m log m)/n is derived. In order to prove that this upper bound is achievable, we design a hybrid routing scheme in which the data traffic is divided into two classes and use different routing strategies: a portion of data will be forwarded with the (partial) support of super nodes in a hierarchical routing fashion, and the rest will be purely routed through RF links in a multi-hop fashion. By properly balancing the load between these two classes of traffic, it is shown that this upper bound is tight when the maximum data rate ratio of FSO and RF transceivers, W2/W1, grows slower than radicn. Under such circumstances, the capacity improvement with the support of FSO nodes, as compared with the results for RF wireless networks in [1], is evaluated. A significant capacity gain will be achieved if W2/W1m log m = Omega(n). The results characterize the number of super nodes and/or the FSO data rate necessary in order to cause a non-trivial increase in the per-node throughput.","PeriodicalId":439952,"journal":{"name":"2007 Information Theory and Applications Workshop","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127888204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19

Group Factorizations and Information Theory 群体分解与信息论

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357607

U. Tamm

引用次数: 1

Distributed Spectrum Sensing for Cognitive Radio Systems 认知无线电系统的分布式频谱感知

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357570

C. da Silva, Brian Choi, Kyouwoong Kim

引用次数: 98

Variational sampling approaches to word confusability 易混淆词的变分抽样方法

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357616

J. R. Hershey, P. Olsen, R. Gopinath

引用次数: 0

Ensemble Weight Enumerators for Protograph-Based Generalized LDPC Codes 基于原型的广义LDPC码的集成权重枚举

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357601

S. Abu-Surra, W. Ryan, D. Divsalar

引用次数: 10

Discriminative Models for Speech Recognition 语音识别的判别模型

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357576

M. Gales

引用次数: 28

MIMO BICM-OFDM Beamforming with Full and Partial CSIT 全CSIT和部分CSIT的MIMO BICM-OFDM波束形成

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357557

E. Akay, E. Sengul, E. Ayanoglu

引用次数: 6

Scanning and Sequential Decision Making for Multidimensional Data 多维数据的扫描与顺序决策

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357568

A. Cohen, N. Merhav, T. Weissman

{"title":"Scanning and Sequential Decision Making for Multidimensional Data","authors":"A. Cohen, N. Merhav, T. Weissman","doi":"10.1109/ITA.2007.4357568","DOIUrl":"https://doi.org/10.1109/ITA.2007.4357568","url":null,"abstract":"We investigate several problems in scanning of multidimensional data arrays, such as universal scanning and prediction (\"scandiction\", for short), and scandiction of noisy data arrays. These problems arise in several aspects of image and video processing, such as predictive coding, filtering and denoising. In predictive coding of images, for example, an image is compressed by coding the prediction error sequence resulting from scandicting it. Thus, it is natural to ask what is the optimal method to scan and predict a given image, what is the resulting minimum prediction loss, and if there exist specific scandiction schemes which are universal in some sense. More specifically, we investigate the following problems: First, given a random field, we examine whether there exists a scandiction scheme which is independent of the field's distribution, yet asymptotically achieves the same performance as if this distribution was known. This question is answered in the affirmative for the set of all spatially stationary random fields and under mild conditions on the loss function. We then discuss the scenario where a non-optimal scanning order is used, yet accompanied by an optimal predictor, and derive a bound on the excess loss compared to optimal scandiction. For individual data arrays, where we show that universal scandictors with respect to arbitrary finite scandictor sets do not exist, we show that the Peano-Hilbert scan has a uniformly small redundancy compared to optimal finite state scandiction. Finally, we examine the scenario where the random field is corrupted by noise, but the scanning and prediction (or filtering) scheme is judged with respect to the underlying noiseless field. A special emphasis is given to the interesting scenarios of binary random fields communicated through binary symmetric channels and Gaussian random fields corrupted by additive white Gaussian noise.","PeriodicalId":439952,"journal":{"name":"2007 Information Theory and Applications Workshop","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115091157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

A Pragmatic Approach to Coded Continuous-Phase Modulation 编码连续相位调制的实用方法

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357559

S. Benedetto, G. Montorsi, A. Perotti, A. Tarable

引用次数: 13

Optimal Allocation of Filters against DDoS Attacks 针对DDoS攻击的过滤器优化配置

2007 Information Theory and Applications Workshop Pub Date : 2007-10-22 DOI: 10.1109/ITA.2007.4357573

Karim El Defrawy, A. Markopoulou, Katerina Argyraki

{"title":"Optimal Allocation of Filters against DDoS Attacks","authors":"Karim El Defrawy, A. Markopoulou, Katerina Argyraki","doi":"10.1109/ITA.2007.4357573","DOIUrl":"https://doi.org/10.1109/ITA.2007.4357573","url":null,"abstract":"Distributed denial-of-service (DDoS) attacks are a major problem in the Internet today. During a DDoS attack, a large number of compromised hosts send unwanted traffic to the victim, thus exhausting the resources of the victim and preventing it from serving its legitimate clients. One of the main mechanisms against DDoS is filtering, which allows routers to selectively block unwanted traffic. Given the magnitude of DDoS attacks and the high cost of filters in the routers today, the successful mitigation of a DDoS attack using filtering crucially depends on the efficient allocation of filtering resources. In this paper, we consider a single router with a limited number of available filters. We study how to optimally allocate filters to attack sources, or entire domains of attack sources, so as to maximize the amount of good traffic preserved, under a constraint on the number of filters. First, we look at the single-tier problem, where the collateral damage on legitimate traffic is high due to the filtering at the granularity of attack domains. Second, we look at the two-tier problem, where we have an additional constraint on the number of filters and filtering is performed at the granularity of attackers and/or domains. We formulate both problems as optimization problems, and we evaluate the optimal solution over a range of realistic attack-scenarios. Our results demonstrate that efficient filter allocation significantly improves the tradeoff between the number of filters used and the amount of legitimate traffic preserved.","PeriodicalId":439952,"journal":{"name":"2007 Information Theory and Applications Workshop","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122013809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14