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Title:

Directed Information on Abstract spaces: Properties and Extremum Problems

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This paper describes a framework in which directed information is defined on abstract spaces. The framework is employed to derive properties of directed information such as convexity, concavity, lower semicontinuity, by using the topology of weak convergence of probability measures on Polish spaces. Two extremum problems of directed information ...

This paper describes a framework in which directed information is defined on abstract spaces. The framework is employed to derive properties of directed information such as convexity, concavity, lower semicontinuity, by using the topology of weak convergence of probability measures on Polish spaces. Two extremum problems of directed information related to capacity of channels with memory and feedback, and non-anticipative and sequential rate distortion are analyzed showing existence of maximizing and minimizing distributions, respectively. ; Comment: 5 pages, to appear in proceedings of International Symposium on Information Theory (ISIT), 2012 Minimize

Year of Publication:

2012-02-05

Document Type:

text

Subjects:

Computer Science - Information Theory ; Mathematics - Functional Analysis ; Mathematics - Probability

Computer Science - Information Theory ; Mathematics - Functional Analysis ; Mathematics - Probability Minimize

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Title:

Expression of Cathepsin B by oligodendrogliomas

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German Medical Science GMS Publishing House; Düsseldorf

Year of Publication:

2010-09-16

Source:

M0122

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Document Type:

conferenceObject

Language:

eng

Subjects:

ddc:610

ddc:610 Minimize

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http://www.egms.de/en/terms.htm

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Title:

Nonanticipative Rate Distortion Function and Filtering Theory: A weak Convergence Approach

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In this paper the relation between nonanticipative rate distortion function (RDF) and Bayesian filtering theory is further investigated on general Polish spaces. The relation is established via an optimization on the space of conditional distributions of the so-called directed information subject to fidelity constraints. Existence of the optimal...

In this paper the relation between nonanticipative rate distortion function (RDF) and Bayesian filtering theory is further investigated on general Polish spaces. The relation is established via an optimization on the space of conditional distributions of the so-called directed information subject to fidelity constraints. Existence of the optimal reproduction distribution of the nonanticipative RDF is shown using the topology of weak convergence of probability measures. Subsequently, we use the solution of the nonanticipative RDF to present the realization of a multidimensional partially observable source over a scalar Gaussian channel. We show that linear encoders are optimal, establishing joint source-channel coding in real-time. ; Comment: 26 pages and 4 figures, part of this work is published in European Control Conference (ECC' 13) Minimize

Year of Publication:

2012-12-29

Document Type:

text

Subjects:

Computer Science - Information Theory ; Computer Science - Systems and Control

Computer Science - Information Theory ; Computer Science - Systems and Control Minimize

DDC:

003 Systems *(computed)*

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Title:

Directed Information on Abstract Spaces: Properties and Variational Equalities

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Directed information or its variants are utilized extensively in the characterization of the capacity of channels with memory and feedback, nonanticipative lossy data compression, and their generalizations to networks. In this paper, we derive several functional and topological properties of directed information for general abstract alphabets (c...

Directed information or its variants are utilized extensively in the characterization of the capacity of channels with memory and feedback, nonanticipative lossy data compression, and their generalizations to networks. In this paper, we derive several functional and topological properties of directed information for general abstract alphabets (complete separable metric spaces) using the topology of weak convergence of probability measures. These include convexity of the set of causally conditioned convolutional distributions, convexity and concavity of directed information with respect to sets of such distributions, weak compactness of families of causally conditioned convolutional distributions, their joint distributions and their marginals. Furthermore, we show lower semicontinuity of directed information, and under certain conditions we also establish continuity of directed information. Finally, we derive variational equalities of directed information, which are analogous to those of mutual information (utilized in Blahut-Arimoto algorithm). In summary, we extend the basic functional and topological properties of mutual information to directed information. Throughout the paper, the importance of the properties of directed information is discussed in the context of extremum problems of directed information. ; Comment: 65 pages, 2 figures, Submitted for publication at the IEEE Transactions on Information Theory Minimize

Year of Publication:

2013-02-16

Document Type:

text

Subjects:

Computer Science - Information Theory ; Mathematics - Functional Analysis ; Mathematics - Optimization and Control ; Mathematics - Probability

Computer Science - Information Theory ; Mathematics - Functional Analysis ; Mathematics - Optimization and Control ; Mathematics - Probability Minimize

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Title:

On the relation of nonanticipative rate distortion function and filtering theory

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In this paper the relation between nonanticipative rate distortion function (RDF) and Bayesian filtering theory is investigated using the topology of weak convergence of probability measures on Polish spaces. The relation is established via an optimization on the space of conditional distributions of the so-called directed information subject to...

In this paper the relation between nonanticipative rate distortion function (RDF) and Bayesian filtering theory is investigated using the topology of weak convergence of probability measures on Polish spaces. The relation is established via an optimization on the space of conditional distributions of the so-called directed information subject to fidelity constraints. Existence of the optimal reproduction distribution of the nonanticipative RDF is shown, while the optimal nonanticipative reproduction conditional distribution for stationary processes is derived in closed form. The realization procedure of nonanticipative RDF which is equivalent to joint-source channel matching for symbol-by-symbol transmission is described, while an example is introduced to illustrate the concepts. ; Comment: 6 pages, 4 figures, final version submitted for publication at 12th Biannual European Control Conference (ECC), 2013 Minimize

Year of Publication:

2012-10-07

Document Type:

text

Subjects:

Computer Science - Information Theory ; Computer Science - Systems and Control ; 60B11 ; 37A50

Computer Science - Information Theory ; Computer Science - Systems and Control ; 60B11 ; 37A50 Minimize

DDC:

003 Systems *(computed)*

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Title:

Causal Rate Distortion Function and Relations to Filtering Theory

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A causal rate distortion function is defined, its solution is described, and its relation to filtering theory is discussed. The relation to filtering is obtained via a causal constraint imposed on the reconstruction kernel to be realizable. ; Comment: 8 pages; 3 figures; Presented in 20th International Symposium on Mathematical Theory of Network...

A causal rate distortion function is defined, its solution is described, and its relation to filtering theory is discussed. The relation to filtering is obtained via a causal constraint imposed on the reconstruction kernel to be realizable. ; Comment: 8 pages; 3 figures; Presented in 20th International Symposium on Mathematical Theory of Networks and Systems (MTNS 2012) Minimize

Year of Publication:

2011-04-05

Document Type:

text

Subjects:

Computer Science - Information Theory

Computer Science - Information Theory Minimize

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Title:

Variational Equalities of Directed Information and Applications

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In this paper we introduce two variational equalities of directed information, which are analogous to those of mutual information employed in the Blahut-Arimoto Algorithm (BAA). Subsequently, we introduce nonanticipative Rate Distortion Function (RDF) ${R}^{na}_{0,n}(D)$ defined via directed information introduced in [1], and we establish its eq...

In this paper we introduce two variational equalities of directed information, which are analogous to those of mutual information employed in the Blahut-Arimoto Algorithm (BAA). Subsequently, we introduce nonanticipative Rate Distortion Function (RDF) ${R}^{na}_{0,n}(D)$ defined via directed information introduced in [1], and we establish its equivalence to Gorbunov-Pinsker's nonanticipatory $\epsilon$-entropy $R^{\varepsilon}_{0,n}(D)$. By invoking certain results we first establish existence of the infimizing reproduction distribution for ${R}^{na}_{0,n}(D)$, and then we give its implicit form for the stationary case. Finally, we utilize one of the variational equalities and the closed form expression of the optimal reproduction distribution to provide an algorithm for the computation of ${R}^{na}_{0,n}(D)$. ; Comment: 5 pages, to appear in proceedings of International Symposium on Information Theory (ISIT), 2013 Minimize

Year of Publication:

2013-01-28

Document Type:

text

Subjects:

Computer Science - Information Theory

Computer Science - Information Theory Minimize

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Title:

Countering DDoS Attacks with Multi-Path Overlay Networks

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Year of Publication:

2006

Document Type:

text

Language:

English

Subjects:

Computer science

Computer science Minimize

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Title:

Countering DoS Attacks With Stateless Multipath Overlays

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Indirection-based overlay networks (IONs) are a promising approach for countering distributed denial of service (DDoS) attacks. Such mechanisms are based on the assumption that attackers will attack a fixed and bounded set of overlay nodes causing service disruption to a small fraction of the users. In addition, attackers cannot eaves-drop on li...

Indirection-based overlay networks (IONs) are a promising approach for countering distributed denial of service (DDoS) attacks. Such mechanisms are based on the assumption that attackers will attack a fixed and bounded set of overlay nodes causing service disruption to a small fraction of the users. In addition, attackers cannot eaves-drop on links inside the network or otherwise gain information that can help them focus their attacks on overlay nodes that are critical for specific communication flows. We develop an analytical model and a new class of attacks that considers both simple and advanced adversaries. We show that the impact of these simple attacks on IONs can severely disrupt communications. We propose a stateless spread-spectrum paradigm to create per-packet path diversity between each pair of end-nodes using a modified ION access protocol. Our system protects end-to-end communications from DoS attacks without sacrificing strong client authentication or allowing an attacker with partial connectivity information to repeatedly disrupt communications. Through analysis, we show that an Akamai-sized overlay can withstand attacks involving over 1.3M "zombie" hosts while providing uninterrupted end-to-end connectivity. By using packet replication, the system can resist attacks that render up to 40% of the nodes inoperable. Surprisingly, our experiments on PlanetLab demonstrate that in many cases end-to-end latency decreases when packet replication is used, with a worst-case increase by a factor of 2.5. Similarly, our system imposes less than 15% performance degradation in the end-to-end throughput, even when subjected to a large DDoS attack. Minimize

Publisher:

ACM Press

Year of Publication:

2005

Document Type:

text

Language:

English

Subjects:

Computer science

Computer science Minimize

DDC:

303 Social processes *(computed)*

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Title:

A new yeast display vector permitting free scFv amino termini can augment ligand binding affinities

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Yeast surface display and sorting by flow cytometry are now widely used to direct the evolution of protein binding such as single-chain antibodies or scFvs. The available commercial yeast display vector pYD1 (Invitrogen) displays the protein of interest flanked on the N-terminus by Aga2, the disulfide of which binds the myristylated surface memb...

Yeast surface display and sorting by flow cytometry are now widely used to direct the evolution of protein binding such as single-chain antibodies or scFvs. The available commercial yeast display vector pYD1 (Invitrogen) displays the protein of interest flanked on the N-terminus by Aga2, the disulfide of which binds the myristylated surface membrane protein Aga1. We have noted that two anti-CD3ε scFvs expressed as fusion proteins suffer a 30- to 100-fold loss of affinity when placed NH 2 terminal to either truncated toxins or human serum albumin. In the course of affinity maturing one of these scFv (FN18) using pYD1 we noted that the affinity towards the ectodomain of monkey CD3εγ was too low to measure. Consequently we rebuilt pYD1 tethering the scFv off the NH 2 terminus of Aga2. This display vector, pYD5, now gave a positive signal displaying FN18 scFv with its ligand, monkey CD3εγ. The apparent equilibrium association constant of the higher affinity scFv directed at human CD3εγ increased ∼3-fold when displayed on pYD5 compared with pYD1. These data show that for certain yeast-displayed scFvs a carboxy-tethered scFv can result in increased ligand-scFv equilibrium association constants and thereby extend the low range of affinity maturation measurements. Minimize

Publisher:

Oxford University Press

Year of Publication:

2005-06-23 06:43:45.0

Document Type:

TEXT

Language:

en

Subjects:

Article

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Rights:

Copyright (C) 2005, Oxford University Press

Copyright (C) 2005, Oxford University Press Minimize

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