Sichere Kommunikation über Abhörkanäle mit mehreren Empfängern und aktiven Störsendern

We derive a state of the art strong secrecy coding scheme for the multi-receiver wiretap channel under the joint and individual secrecy constraints. we show that individual secrecy can utilize the concept of mutual trust to achieve a larger capacity region compared to the joint one. Further, we derive a full characterization for the list secrecy capacity of arbitrarily varying wiretap channels and establish some interesting results for the continuity and additivity behaviour of the capacity.Für den Abhörkanal mit mehreren Empfängern wird ein Kodierungsschema hergeleitet unter dem gemeinsamen als auch individuellem Sicherheitskriterium. Das individuelle Kriterium basiert auf dem Konzept des gegenseitigen Vertrauens, um eine größere Kapazitätsregion zu erreichen. Weiterhin wird eine vollständige Charakterisierung der Sicherheitskapazität für den beliebig variierenden Kanals aufgestellt, sowie Eigenschaften bezüglich der Kontinuität und des Additivitätsverhalten bewiesen

Secret Message Transmission over Quantum Channels under Adversarial Quantum Noise: Secrecy Capacity and Super-Activation

We determine the secrecy capacities of AVQCs (arbitrarily varying quantum channels). Both secrecy capacity with average error probability and with maximal error probability are derived. Both derivations are based on one common code construction. The code we construct fulfills a stringent secrecy requirement, which is called the strong code concept. We determine when the secrecy capacity is a continuous function of the system parameters and completely characterize its discontinuity points both for average error criterion and for maximal error criterion. Furthermore, we prove the phenomenon "super-activation" for secrecy capacities of AVQCs, i.e., two quantum channels both with zero secrecy capacity, which, if used together, allow secure transmission with positive capacity. We also discuss the relations between the entanglement distillation capacity, the entanglement generating capacity, and the strong subspace transmission capacity for AVQCs.Comment: arXiv admin note: text overlap with arXiv:1702.0348

Informationsübertragung durch Quantenkanäle

This PhD thesis represents work done between Aug. 2003 and Dec. 2006 in Reinhard F. Werner's quantum information theory group at Technische Universität Braunschweig, and Artur Ekert's Centre for Quantum Computation at the University of Cambridge. Quantum information science combines ideas from physics, computer science and information theory to investigate how quintessentially quantum mechanical effects such as superposition and entanglement can be employed for the handling and transfer of information. My thesis falls into the field of abstract quantum information theory, which is concerned with the fundamental resources for quantum information processing and their interconversion and tradeoffs. Every such processing of quantum information can be represented as a quantum channel: a completely positive and trace-preserving map between observable algebras associated to physical systems. This work investigates both fundamental properties of quantum channels (mostly in Chs. 3 and 4) and their asymptotic capacities for classical as well as quantum information transfer (in Chs. 5 through 8).Diese Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) entstand zwischen August 2003 und Dezember 2006 in Prof. Reinhard F. Werners Arbeitsgruppe Quanteninformationstheorie an der Technischen Universität Braunschweig und Prof. Artur Ekerts Centre for Quantum Computation an der Universität Cambridge. Die Quanteninformationswissenschaft untersucht mit den Ideen und Methoden der Physik, der Informatik und der Informationstheorie, wie sich charakteristisch quantenphysikalische Effekte, beispielsweise Superposition und Verschränkung, zur Verarbeitung und Übertragung von Information nutzbar machen lassen. Die vorliegende Dissertation fällt in das Gebiet der abstrakten Quanteninformationstheorie, die die grundlegenden Ressourcen für die Verarbeitung von Quanteninformation sowie deren Wechselbeziehungen und Abhängigkeiten untersucht. Eine jede solche Verarbeitung von Quanteninformation läßt sich mathematisch beschreiben als sogenannter Quantenkanal, eine vollständig positive und spurerhaltende Abbildung zwischen den physikalischen Systemen zugeordneten Observablen-Algebren. In dieser Arbeit werden sowohl grundlegende Eigenschaften solcher Quantenkanäle (vor allem in den Kap. 3 und Kap. 4) als auch ihre asymptotischen Kapazitäten für die Übertragung von klassischer Information und Quanteninformation (in Kap. 5 bis 8) untersucht

Journal of Telecommunications and Information Technology, 2014, nr 1

kwartalni

Second Generation General System Theory: Perspectives in Philosophy and Approaches in Complex Systems

Following the classical work of Norbert Wiener, Ross Ashby, Ludwig von Bertalanffy and many others, the concept of System has been elaborated in different disciplinary fields, allowing interdisciplinary approaches in areas such as Physics, Biology, Chemistry, Cognitive Science, Economics, Engineering, Social Sciences, Mathematics, Medicine, Artificial Intelligence, and Philosophy. The new challenge of Complexity and Emergence has made the concept of System even more relevant to the study of problems with high contextuality. This Special Issue focuses on the nature of new problems arising from the study and modelling of complexity, their eventual common aspects, properties and approaches—already partially considered by different disciplines—as well as focusing on new, possibly unitary, theoretical frameworks. This Special Issue aims to introduce fresh impetus into systems research when the possible detection and correction of mistakes require the development of new knowledge. This book contains contributions presenting new approaches and results, problems and proposals. The context is an interdisciplinary framework dealing, in order, with electronic engineering problems; the problem of the observer; transdisciplinarity; problems of organised complexity; theoretical incompleteness; design of digital systems in a user-centred way; reaction networks as a framework for systems modelling; emergence of a stable system in reaction networks; emergence at the fundamental systems level; behavioural realization of memoryless functions

Space programs summary no. 37-32, volume iv, for the period 1 february - 31 march 1965. supporting research and advanced development

Space programs on telecommunications, space science, propulsion, engineer mechanics, guidance and control, systems, and project engineerin

Wavelets and Subband Coding

First published in 1995, Wavelets and Subband Coding offered a unified view of the exciting field of wavelets and their discrete-time cousins, filter banks, or subband coding. The book developed the theory in both continuous and discrete time, and presented important applications. During the past decade, it filled a useful need in explaining a new view of signal processing based on flexible time-frequency analysis and its applications. Since 2007, the authors now retain the copyright and allow open access to the book