Pub Date : 2012-09-01DOI: 10.1109/ITW.2012.6404710
Arash Einolghozati, Mohsen Sardari, F. Fekri
Molecular communication is an expanding body of research. Recent advances in biology have encouraged using genetically engineered bacteria as the main component in the molecular communication. This has stimulated a new line of research that attempts to study molecular communication among bacteria from an information-theoretic point of view. Due to high randomness in the individual behavior of the bacterium, reliable communication between two bacteria is almost impossible. Therefore, we recently proposed that a population of bacteria in a cluster is considered as a node capable of molecular transmission and reception. This proposition enables us to form a reliable node out of many unreliable bacteria. The bacteria inside a node sense the environment and respond accordingly. In this paper, we study the communication between two nodes, one acting as the transmitter and the other as the receiver. We consider the case in which the information is encoded in the concentration of molecules by the transmitter. The molecules produced by the bacteria in the transmitter node propagate in the environment via the diffusion process. Then, their concentration sensed by the bacteria in the receiver node would decode the information. The randomness in the communication is caused by both the error in the molecular production at the transmitter and the reception of molecules at the receiver. We study the theoretical limits of the information transfer rate in such a setup versus the number of bacteria per node. Finally, we consider M-ary modulation schemes and study the achievable rates and their error probabilities.
{"title":"Molecular communication between two populations of bacteria","authors":"Arash Einolghozati, Mohsen Sardari, F. Fekri","doi":"10.1109/ITW.2012.6404710","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404710","url":null,"abstract":"Molecular communication is an expanding body of research. Recent advances in biology have encouraged using genetically engineered bacteria as the main component in the molecular communication. This has stimulated a new line of research that attempts to study molecular communication among bacteria from an information-theoretic point of view. Due to high randomness in the individual behavior of the bacterium, reliable communication between two bacteria is almost impossible. Therefore, we recently proposed that a population of bacteria in a cluster is considered as a node capable of molecular transmission and reception. This proposition enables us to form a reliable node out of many unreliable bacteria. The bacteria inside a node sense the environment and respond accordingly. In this paper, we study the communication between two nodes, one acting as the transmitter and the other as the receiver. We consider the case in which the information is encoded in the concentration of molecules by the transmitter. The molecules produced by the bacteria in the transmitter node propagate in the environment via the diffusion process. Then, their concentration sensed by the bacteria in the receiver node would decode the information. The randomness in the communication is caused by both the error in the molecular production at the transmitter and the reception of molecules at the receiver. We study the theoretical limits of the information transfer rate in such a setup versus the number of bacteria per node. Finally, we consider M-ary modulation schemes and study the achievable rates and their error probabilities.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"182 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116607150","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404680
Eiichi Sakurai, K. Yamanishi
In this study, we address the issue of tracking changes in statistical models under the assumption that the statistical models used for generating data may change over time. This issue is of great importance for learning from non-stationary data. One of the promising approaches for resolving this issue is the use of the dynamic model selection (DMS) method, in which a model sequence is estimated on the basis of the minimum description length (MDL) principle. Another approach is the use of the infinite hidden Markov model (HMM), which is a non-parametric learning method for the case with an infinite number of states. In this study, we propose a few new variants of DMS and propose efficient algorithms to minimize the total code-length by using the sequential normalized maximum likelihood. We compare these algorithms with infinite HMM to investigate their statistical model change detection performance, and we empirically demonstrate that one of our variants of DMS significantly outperforms infinite HMM in terms of change-point detection accuracy.
{"title":"Comparison of dynamic model selection with infinite HMM for statistical model change detection","authors":"Eiichi Sakurai, K. Yamanishi","doi":"10.1109/ITW.2012.6404680","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404680","url":null,"abstract":"In this study, we address the issue of tracking changes in statistical models under the assumption that the statistical models used for generating data may change over time. This issue is of great importance for learning from non-stationary data. One of the promising approaches for resolving this issue is the use of the dynamic model selection (DMS) method, in which a model sequence is estimated on the basis of the minimum description length (MDL) principle. Another approach is the use of the infinite hidden Markov model (HMM), which is a non-parametric learning method for the case with an infinite number of states. In this study, we propose a few new variants of DMS and propose efficient algorithms to minimize the total code-length by using the sequential normalized maximum likelihood. We compare these algorithms with infinite HMM to investigate their statistical model change detection performance, and we empirically demonstrate that one of our variants of DMS significantly outperforms infinite HMM in terms of change-point detection accuracy.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132883403","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404679
Panu Luosto, C. Giurcăneanu, P. Kontkanen
Theoretical advances of the last decade have led to novel methodologies for probability density estimation by irregular histograms and penalized maximum likelihood. Here we consider two of them: the first one is based on the idea of minimizing the excess risk, while the second one employs the concept of the normalized maximum likelihood (NML). Apparently, the previous literature does not contain any comparison of the two approaches. To fill the gap, we provide in this paper theoretical and empirical results for clarifying the relationship between the two methodologies. Additionally, we introduce a new variant of the NML histogram. For the sake of completeness, we consider also a more advanced NML-based method that uses the measurements to approximate the unknown density by a mixture of densities selected from a predefined family.
{"title":"Construction of irregular histograms by penalized maximum likelihood: A comparative study","authors":"Panu Luosto, C. Giurcăneanu, P. Kontkanen","doi":"10.1109/ITW.2012.6404679","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404679","url":null,"abstract":"Theoretical advances of the last decade have led to novel methodologies for probability density estimation by irregular histograms and penalized maximum likelihood. Here we consider two of them: the first one is based on the idea of minimizing the excess risk, while the second one employs the concept of the normalized maximum likelihood (NML). Apparently, the previous literature does not contain any comparison of the two approaches. To fill the gap, we provide in this paper theoretical and empirical results for clarifying the relationship between the two methodologies. Additionally, we introduce a new variant of the NML histogram. For the sake of completeness, we consider also a more advanced NML-based method that uses the measurements to approximate the unknown density by a mixture of densities selected from a predefined family.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130720618","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404704
Sachin Kadloor, N. Kiyavash, P. Venkitasubramaniam
In multi-tasking systems where a finite resource is to be shared, a scheduler dictates how the resource is divided among competing processes. Examples of systems which have schedulers include, a computer where the CPU needs to be shared between the different threads running, a cloud computing infrastructure with shared computing resources, a network router serving packets from different streams etc. In such situations, when a processor is shared by multiple users, the delays experienced by jobs from one user are a function of the arrival pattern of jobs from other users, and the scheduling policy of the server. Consequently, a scheduling system creates a timing side channel in which information about arrival pattern from one user is inadvertently leaked to another. In this work, this information leakage is studied for a two user scheduling system. We first introduce a measure of privacy and then demonstrate that no scheduler can provide maximum privacy without idling/taking vacations, and consequently no policy can simultaneously be delay and privacy optimal.
{"title":"Scheduling with privacy constraints","authors":"Sachin Kadloor, N. Kiyavash, P. Venkitasubramaniam","doi":"10.1109/ITW.2012.6404704","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404704","url":null,"abstract":"In multi-tasking systems where a finite resource is to be shared, a scheduler dictates how the resource is divided among competing processes. Examples of systems which have schedulers include, a computer where the CPU needs to be shared between the different threads running, a cloud computing infrastructure with shared computing resources, a network router serving packets from different streams etc. In such situations, when a processor is shared by multiple users, the delays experienced by jobs from one user are a function of the arrival pattern of jobs from other users, and the scheduling policy of the server. Consequently, a scheduling system creates a timing side channel in which information about arrival pattern from one user is inadvertently leaked to another. In this work, this information leakage is studied for a two user scheduling system. We first introduce a measure of privacy and then demonstrate that no scheduler can provide maximum privacy without idling/taking vacations, and consequently no policy can simultaneously be delay and privacy optimal.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124981782","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404747
S. Rini
The chain graph representations of an achievable scheme is a recently introduced theoretical tool to derive achievable regions based on superposition coding and binning for a general, single-hop, multi-terminal network. It allows for a compact representation of complex transmission strategies and the derivation of the corresponding achievable region for a large class of channels. In this paper we extend the original concept to include a new random coding technique that generalizes superposition coding and binning. With this coding strategy, one generates a top codebook conditionally dependent on the bottom codeword and successively uses binning to impose a different conditional distribution between top and bottom codewords. The region achieved with this strategy relates to the Kullback-Leibler divergence between the distribution of the codewords at generation and the distribution after binning.
{"title":"An extension to the chain graph representation of an achievable scheme","authors":"S. Rini","doi":"10.1109/ITW.2012.6404747","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404747","url":null,"abstract":"The chain graph representations of an achievable scheme is a recently introduced theoretical tool to derive achievable regions based on superposition coding and binning for a general, single-hop, multi-terminal network. It allows for a compact representation of complex transmission strategies and the derivation of the corresponding achievable region for a large class of channels. In this paper we extend the original concept to include a new random coding technique that generalizes superposition coding and binning. With this coding strategy, one generates a top codebook conditionally dependent on the bottom codeword and successively uses binning to impose a different conditional distribution between top and bottom codewords. The region achieved with this strategy relates to the Kullback-Leibler divergence between the distribution of the codewords at generation and the distribution after binning.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125517569","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404761
Fuchun Lin, F. Oggier
We consider lattice coding over a Gaussian wiretap channel with respect to the secrecy gain, a lattice invariant introduced in [1] to characterize the confusion that a chosen lattice can cause at the eavesdropper. The secrecy gain of the best unimodular lattices constructed from binary self-dual codes in dimension n, 24 ≤ n ≤ 32 are calculated. Numerical upper bounds on the secrecy gain of unimodular lattices in general and of unimodular lattices constructed from binary self-dual codes in particular are derived for all even dimensions up to 168.
{"title":"Gaussian wiretap lattice codes from binary self-dual codes","authors":"Fuchun Lin, F. Oggier","doi":"10.1109/ITW.2012.6404761","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404761","url":null,"abstract":"We consider lattice coding over a Gaussian wiretap channel with respect to the secrecy gain, a lattice invariant introduced in [1] to characterize the confusion that a chosen lattice can cause at the eavesdropper. The secrecy gain of the best unimodular lattices constructed from binary self-dual codes in dimension n, 24 ≤ n ≤ 32 are calculated. Numerical upper bounds on the secrecy gain of unimodular lattices in general and of unimodular lattices constructed from binary self-dual codes in particular are derived for all even dimensions up to 168.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124851545","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404636
Y. Dodis, Yuzhen Yu
Recently, there has been renewed interest in basing cryptographic primitives on weak secrets, where the only information about the secret is some non-trivial amount of (min-) entropy. From a formal point of view, such results require to upper bound the expectation of some function f(X), where X is a weak source in question. We show an elementary inequality which essentially upper bounds such `weak expectation' by two terms, the first of which is independent of f, while the second only depends on the `variance' of f under uniform distribution. Quite remarkably, as relatively simple corollaries of this elementary inequality, we obtain some `unexpected' results, in several cases noticeably simplifying/improving prior techniques for the same problem. Examples include non-malleable extractors, leakage-resilient symmetric encryption, seed-dependent condensers and improved entropy loss for the leftover hash lemma.
{"title":"Overcoming weak expectations","authors":"Y. Dodis, Yuzhen Yu","doi":"10.1109/ITW.2012.6404636","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404636","url":null,"abstract":"Recently, there has been renewed interest in basing cryptographic primitives on weak secrets, where the only information about the secret is some non-trivial amount of (min-) entropy. From a formal point of view, such results require to upper bound the expectation of some function f(X), where X is a weak source in question. We show an elementary inequality which essentially upper bounds such `weak expectation' by two terms, the first of which is independent of f, while the second only depends on the `variance' of f under uniform distribution. Quite remarkably, as relatively simple corollaries of this elementary inequality, we obtain some `unexpected' results, in several cases noticeably simplifying/improving prior techniques for the same problem. Examples include non-malleable extractors, leakage-resilient symmetric encryption, seed-dependent condensers and improved entropy loss for the leftover hash lemma.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125236544","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404678
Amin Karbasi, Morteza Zadimoghaddam
In conventional group testing, the goal is to detect a small subset of defecting items D in a large population N by grouping arbitrary subset of N into different pools. The result of each group test T is a binary output depending on whether the group contains a defective item or not. The main challenge is to minimize the number of pools required to identify the set D. Motivated by applications in network monitoring and infection propagation, we consider the problem of group testing with graph constraints. As opposed to conventional group testing where any subset of items can be pooled, here a test is admissible if it induces a connected subgraph H ⊂ G. In contrast to the non-adaptive pooling process used in previous work, we first show that by exploiting an adaptive strategy, one can dramatically reduce the number of tests. More specifically, for any graph G, we devise a 2-approximation algorithm (and hence order optimal) that locates the set of defective items D. To obtain a good compromise between adaptive and non-adaptive strategies, we then devise a multi-stage algorithm. In particular, we show that if the set of defective items are uniformly distributed, then an l-stage pooling strategy can identify the defective set in O(l·|D|·|N|1/l) tests, on the average. In particular, for l = log(|N|) stages, the number of tests reduces to 4|D| log(|N|), which in turn is order optimum.
{"title":"Sequential group testing with graph constraints","authors":"Amin Karbasi, Morteza Zadimoghaddam","doi":"10.1109/ITW.2012.6404678","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404678","url":null,"abstract":"In conventional group testing, the goal is to detect a small subset of defecting items D in a large population N by grouping arbitrary subset of N into different pools. The result of each group test T is a binary output depending on whether the group contains a defective item or not. The main challenge is to minimize the number of pools required to identify the set D. Motivated by applications in network monitoring and infection propagation, we consider the problem of group testing with graph constraints. As opposed to conventional group testing where any subset of items can be pooled, here a test is admissible if it induces a connected subgraph H ⊂ G. In contrast to the non-adaptive pooling process used in previous work, we first show that by exploiting an adaptive strategy, one can dramatically reduce the number of tests. More specifically, for any graph G, we devise a 2-approximation algorithm (and hence order optimal) that locates the set of defective items D. To obtain a good compromise between adaptive and non-adaptive strategies, we then devise a multi-stage algorithm. In particular, we show that if the set of defective items are uniformly distributed, then an l-stage pooling strategy can identify the defective set in O(l·|D|·|N|1/l) tests, on the average. In particular, for l = log(|N|) stages, the number of tests reduces to 4|D| log(|N|), which in turn is order optimum.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123521512","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404759
Hamid G. Bafghi, B. Seyfe, M. Mirmohseni, M. Aref
This paper introduces a new applicable Gaussian wiretap channel with side information. In this channel, the state of the channel to the wiretapper is separated from the main channel's one. It means that the legitimate receiver and the wiretapper are listening to the transmitted signal through the different channels with different channel states which may have some correlation to each other. The state of the main channel, is assumed to be known at the transmitter, helps the sender to encrypt its messages. The achievable equivocation-rate region for this model is drived in the Gaussian case and the results are reduced to the previous works as special cases.
{"title":"On the achievable rate region of a new Gaussian wiretap channel with side information","authors":"Hamid G. Bafghi, B. Seyfe, M. Mirmohseni, M. Aref","doi":"10.1109/ITW.2012.6404759","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404759","url":null,"abstract":"This paper introduces a new applicable Gaussian wiretap channel with side information. In this channel, the state of the channel to the wiretapper is separated from the main channel's one. It means that the legitimate receiver and the wiretapper are listening to the transmitted signal through the different channels with different channel states which may have some correlation to each other. The state of the main channel, is assumed to be known at the transmitter, helps the sender to encrypt its messages. The achievable equivocation-rate region for this model is drived in the Gaussian case and the results are reduced to the previous works as special cases.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130287916","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 : 2012-09-01DOI: 10.1109/ITW.2012.6404724
Shenghao Yang
A coding approach based on the superposition structure is proposed for linear operator channels. Under a subspace decoding rule, a lower bound on the maximum achievable rate of this coding approach is characterized. Under the subspace decoding rule, this coding approach is capacity achieving for a class of linear operator channels, and it can potentially achieve higher rates than the subspace coding approach.
{"title":"Superposition coding for linear operator channels over finite fields","authors":"Shenghao Yang","doi":"10.1109/ITW.2012.6404724","DOIUrl":"https://doi.org/10.1109/ITW.2012.6404724","url":null,"abstract":"A coding approach based on the superposition structure is proposed for linear operator channels. Under a subspace decoding rule, a lower bound on the maximum achievable rate of this coding approach is characterized. Under the subspace decoding rule, this coding approach is capacity achieving for a class of linear operator channels, and it can potentially achieve higher rates than the subspace coding approach.","PeriodicalId":325771,"journal":{"name":"2012 IEEE Information Theory Workshop","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114080959","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}
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