Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895560
Y. Kimura, A. Watanabe, T. Katoh, B. B. Bista, T. Takata
In recent years, the use of Weblog is increasing rapidly and some people are using functions to record referer (URL of the page that the site visitor was viewing immediately before) and create back-links to the URL. Recently, as the main purpose to guide visitors to harmful sites, people are using this function to misinterpret referer information and access a large number of sites indiscriminately causing the problem called referrer spam. To combat the referrer spam, the authors have proposed the referrer spam blocking system using Bayesian filter. However, the proposed system has non-negligible false negative (i.e. undetected spam request) ratio of 12%. In this paper, we improve the previous proposed system by introducing image optical character recognition technique. We implement prototype and evaluate computational cost and filtering performance of the proposed scheme and we attain low false negative ratio with reasonable additional computational cost.
{"title":"Improvement of Referrer SPAM blocking system","authors":"Y. Kimura, A. Watanabe, T. Katoh, B. B. Bista, T. Takata","doi":"10.1109/ISITA.2008.4895560","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895560","url":null,"abstract":"In recent years, the use of Weblog is increasing rapidly and some people are using functions to record referer (URL of the page that the site visitor was viewing immediately before) and create back-links to the URL. Recently, as the main purpose to guide visitors to harmful sites, people are using this function to misinterpret referer information and access a large number of sites indiscriminately causing the problem called referrer spam. To combat the referrer spam, the authors have proposed the referrer spam blocking system using Bayesian filter. However, the proposed system has non-negligible false negative (i.e. undetected spam request) ratio of 12%. In this paper, we improve the previous proposed system by introducing image optical character recognition technique. We implement prototype and evaluate computational cost and filtering performance of the proposed scheme and we attain low false negative ratio with reasonable additional computational cost.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116985366","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895613
Haewoon Nam, Mohamed-Slim Alouini
This paper investigates a simple analytical approach that yields the optimal switching thresholds for multi-branch switched diversity systems. It also presents a performance optimization based on these optimal thresholds. For multi-branch switched diversity systems, the optimal fixed switching threshold is not only a function of the average channel SNR but also a function of the number of diversity branches. Conventional multi-branch switched diversity systems use a single fixed switching threshold, where computing this optimal threshold is not a simple task when the number of diversity branches is high. We propose a novel multi-branch switched diversity system that is based on a set of adaptive switching thresholds instead of a single fixed switching threshold, where a different switching threshold is used every switching. Thanks to the fact that each switching threshold in the set depends only on the remaining diversity branches, the proposed system allows a simple optimization for these switching thresholds. Furthermore, numerical and simulation results show that the proposed adaptive switched diversity system outperforms the conventional system.
{"title":"Multi-branch switched diversity with adaptive switching thresholds","authors":"Haewoon Nam, Mohamed-Slim Alouini","doi":"10.1109/ISITA.2008.4895613","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895613","url":null,"abstract":"This paper investigates a simple analytical approach that yields the optimal switching thresholds for multi-branch switched diversity systems. It also presents a performance optimization based on these optimal thresholds. For multi-branch switched diversity systems, the optimal fixed switching threshold is not only a function of the average channel SNR but also a function of the number of diversity branches. Conventional multi-branch switched diversity systems use a single fixed switching threshold, where computing this optimal threshold is not a simple task when the number of diversity branches is high. We propose a novel multi-branch switched diversity system that is based on a set of adaptive switching thresholds instead of a single fixed switching threshold, where a different switching threshold is used every switching. Thanks to the fact that each switching threshold in the set depends only on the remaining diversity branches, the proposed system allows a simple optimization for these switching thresholds. Furthermore, numerical and simulation results show that the proposed adaptive switched diversity system outperforms the conventional system.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115337660","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895583
S. Wahls, H. Boche
We consider equalization of multiple-input multiple-output (MIMO) two-tap channels under a causality constraint. Due to the work of Treil it is well known, that for causal equalizers of N + 1 times N channels the stability norm can grow exponentially fast with N, while it is upper bounded independently of N for the pseudoinverse. In this paper we give a illustrative example for a two-tap channel which exhibits this effect. Monte-Carlo simulations indicate, that this behavior is exemplary for two-tap channels with a strong second tap. Based on further simulations, we observe a rule of thumb on how much antenna diversity is necessary for causal equalization in the general N + K times N case.
{"title":"Impact of dimension on causal equalization of the MIMO two-tap channel","authors":"S. Wahls, H. Boche","doi":"10.1109/ISITA.2008.4895583","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895583","url":null,"abstract":"We consider equalization of multiple-input multiple-output (MIMO) two-tap channels under a causality constraint. Due to the work of Treil it is well known, that for causal equalizers of N + 1 times N channels the stability norm can grow exponentially fast with N, while it is upper bounded independently of N for the pseudoinverse. In this paper we give a illustrative example for a two-tap channel which exhibits this effect. Monte-Carlo simulations indicate, that this behavior is exemplary for two-tap channels with a strong second tap. Based on further simulations, we observe a rule of thumb on how much antenna diversity is necessary for causal equalization in the general N + K times N case.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116031338","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895389
Anxiao Jiang, Jehoshua Bruck
Flash memories are the most widely used type of non-volatile electronic memories. Compared to magnetic recording and optical recording, flash memories have the unique property that their cell levels, which represent data, are programmed using an iterative procedure that monotonically shifts each cell level upward toward its target value. In this paper, we study the capacity of flash memories to store data. We explore the relationship among their capacity, programming precision and programming time. The study is focused on the capacity of single cells, and an optimal programming algorithm is presented.
{"title":"On the capacity of flash memories","authors":"Anxiao Jiang, Jehoshua Bruck","doi":"10.1109/ISITA.2008.4895389","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895389","url":null,"abstract":"Flash memories are the most widely used type of non-volatile electronic memories. Compared to magnetic recording and optical recording, flash memories have the unique property that their cell levels, which represent data, are programmed using an iterative procedure that monotonically shifts each cell level upward toward its target value. In this paper, we study the capacity of flash memories to store data. We explore the relationship among their capacity, programming precision and programming time. The study is focused on the capacity of single cells, and an optimal programming algorithm is presented.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116294301","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895475
H. Kostadinov, H. Morita, N. Iijima, N. Manev
A new construction of double error correctable integer codes and their application to QAM scheme are presented. Soft decoding algorithm for multiple error correctable integer code which are suited to any modulation scheme (QAM, PSK, ASK) will be introduced. Comparison of bit error rate (BER) versus signal-to-noise ratio (SNR) between soft and hard decoding using integer coded modulation (ICM) shows us that we can obtain approximately 2 dB coding gain.
{"title":"Double error correctable integer code and its application to QAM","authors":"H. Kostadinov, H. Morita, N. Iijima, N. Manev","doi":"10.1109/ISITA.2008.4895475","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895475","url":null,"abstract":"A new construction of double error correctable integer codes and their application to QAM scheme are presented. Soft decoding algorithm for multiple error correctable integer code which are suited to any modulation scheme (QAM, PSK, ASK) will be introduced. Comparison of bit error rate (BER) versus signal-to-noise ratio (SNR) between soft and hard decoding using integer coded modulation (ICM) shows us that we can obtain approximately 2 dB coding gain.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"195 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115647827","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895406
Su-Wan Park, Dohee Yi, Sanguk Shin
This paper proposes a practical key management scheme using the frame-based feature in order to efficiently manage multi-keys used for layered access control of H.264/SVC. The efficiency of the proposed scheme is summarized in the following three points. 1) It offers implicit authentication in video content encryption/decryption. 2) It provides the security in key transmission through the network, and 3) has the robustness against brute-force attack as using all different NAL unit keys in the video sequence.
{"title":"A practical key management scheme using the frame-based features for layered access control of H.264/SVC","authors":"Su-Wan Park, Dohee Yi, Sanguk Shin","doi":"10.1109/ISITA.2008.4895406","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895406","url":null,"abstract":"This paper proposes a practical key management scheme using the frame-based feature in order to efficiently manage multi-keys used for layered access control of H.264/SVC. The efficiency of the proposed scheme is summarized in the following three points. 1) It offers implicit authentication in video content encryption/decryption. 2) It provides the security in key transmission through the network, and 3) has the robustness against brute-force attack as using all different NAL unit keys in the video sequence.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121756044","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895654
Jung-Soo Chung, Young-Sik Kim, Jong-Seon No, Habong Chung
In this paper, we enumerate the number of distinct autocorrelation distributions of M-ary Sidel'nikov sequences of given length, while we change the primitive element for generating the sequence.
本文列举了给定长度的m - y Sidel'nikov序列的不同自相关分布的个数，并改变了生成序列的原元。
{"title":"On the number of distinct autocorrelation distributions of M-ary Sidel'nikov sequences","authors":"Jung-Soo Chung, Young-Sik Kim, Jong-Seon No, Habong Chung","doi":"10.1109/ISITA.2008.4895654","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895654","url":null,"abstract":"In this paper, we enumerate the number of distinct autocorrelation distributions of M-ary Sidel'nikov sequences of given length, while we change the primitive element for generating the sequence.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123928971","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895477
A. Barbero, G. Horler, E. Rosnes, O. Ytrehus
In this paper we study and compare methods for representing information for transmission on inductively coupled channels. We introduce combined runlength and power constraints on modulation codes for such channels, calculate the capacities of these new constraints, and propose new codes that meet the constraints.
{"title":"Modulation codes for reader-tag communication on inductively coupled channels","authors":"A. Barbero, G. Horler, E. Rosnes, O. Ytrehus","doi":"10.1109/ISITA.2008.4895477","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895477","url":null,"abstract":"In this paper we study and compare methods for representing information for transmission on inductively coupled channels. We introduce combined runlength and power constraints on modulation codes for such channels, calculate the capacities of these new constraints, and propose new codes that meet the constraints.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124210751","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895541
X. Liang, Wei Li, T. Gulliver
Due to the fact that wireless sensor nodes are spatially distributed throughout the area of interest, event detection must be implemented in a distributed way. Unlike related distributed detection schemes, our proposed approach does not need a pre-designated fusion node. This greatly improves network scalability. In this paper, we provide closed-form expressions for the probability of detection error and probability of false alarm. These results are validated by extensive simulation.
{"title":"Random distributed detection for wireless sensor networks","authors":"X. Liang, Wei Li, T. Gulliver","doi":"10.1109/ISITA.2008.4895541","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895541","url":null,"abstract":"Due to the fact that wireless sensor nodes are spatially distributed throughout the area of interest, event detection must be implemented in a distributed way. Unlike related distributed detection schemes, our proposed approach does not need a pre-designated fusion node. This greatly improves network scalability. In this paper, we provide closed-form expressions for the probability of detection error and probability of false alarm. These results are validated by extensive simulation.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124142034","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}
Pub Date : 2008-12-01DOI: 10.1109/ISITA.2008.4895581
N. Sharma, S. Shamai
The capacity-achieving input distribution for many channels like the additive white Gaussian noise (AWGN) channels under a peak power constraint is discrete with a finite number of mass points. The number of mass points is itself a variable and figuring it out is part of the optimization problem. We wish to understand the behavior of the optimal input distribution at the transition points where the number of mass points changes. We give a new set of necessary and sufficient conditions at the transition points, which offer new insights into the transition and make the computation of the optimal distribution easier. These conditions can be simplified, at least in the real channel case, by assuming the conjecture that the number of mass points increases monotonically and by at most one as the constraint on the input is relaxed. In particular, we show that for zero mean, unit variance Gaussian noise, the peak amplitude A of 1:671 and 2:786 mark the points where the binary and ternary signaling respectively are no longer optimal.
{"title":"Characterizing the discrete capacity achieving distribution with peak power constraint at the transition points","authors":"N. Sharma, S. Shamai","doi":"10.1109/ISITA.2008.4895581","DOIUrl":"https://doi.org/10.1109/ISITA.2008.4895581","url":null,"abstract":"The capacity-achieving input distribution for many channels like the additive white Gaussian noise (AWGN) channels under a peak power constraint is discrete with a finite number of mass points. The number of mass points is itself a variable and figuring it out is part of the optimization problem. We wish to understand the behavior of the optimal input distribution at the transition points where the number of mass points changes. We give a new set of necessary and sufficient conditions at the transition points, which offer new insights into the transition and make the computation of the optimal distribution easier. These conditions can be simplified, at least in the real channel case, by assuming the conjecture that the number of mass points increases monotonically and by at most one as the constraint on the input is relaxed. In particular, we show that for zero mean, unit variance Gaussian noise, the peak amplitude A of 1:671 and 2:786 mark the points where the binary and ternary signaling respectively are no longer optimal.","PeriodicalId":338675,"journal":{"name":"2008 International Symposium on Information Theory and Its Applications","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129641946","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：