11 research outputs found

    Entangled matrix builders

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    Matrices are often built and designed by applying procedures from lower order matrices. Matrix tensor products, direct sums and multiplication of matrices retain certain properties of the lower order matrices; matrices produced by these procedures are said to be {\em separable}. {\em Entangled} matrices is the term used for matrices which are not separable. Here design methods for entangled matrices are derived. These can retain properties of lower order matrices or acquire new required properties. Entangled matrices are often required in practice and a number of applications of the designs are given. Methods with which to construct multidimensional entangled paraunitary matrices are derived; these have applications for wavelet and filter bank design. New entangled unitary matrices are designed; these are used in quantum information theory. Efficient methods for designing new full diversity constellations of unitary matrices with excellent {\em quality} (a defined term) for space time applications are given

    Construction of New Optimal Z-Complementary Code Sets from Z-Paraunitary Matrices

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    In this paper, we first introduce a novel concept, called Z-paraunitary (ZPU) matrices. These ZPU matrices include conventional PU matrices as a special case. Then, we show that there exists an equivalence between a ZPU matrix and a Z-complementary code set (ZCCS) when the latter is expressed as a matrix with polynomial entries. The proposed ZPU matrix has an advantage over the conventional PU matrix with regard to the availability of wider range of matrix sizes and sequence lengths. In addition, the proposed construction framework can accommodate more choices of ZCCS parameters compared to the existing works

    Cryptographic schemes, key exchange, public key.

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    General cryptographic schemes are presented where keys can be one-time or ephemeral. Processes for key exchange are derived. Public key cryptographic schemes based on the new systems are established. Authentication and signature schemes are easy to implement. The schemes may be integrated with error-correcting coding schemes so that encryption/coding and decryption/decoding may be done simultaneously

    Performance enhancement solutions in wireless communication networks

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    In this dissertation thesis, we study the new relaying protocols for different wireless network systems. We analyze and evaluate an efficiency of the transmission in terms of the outage probability over Rayleigh fading channels by mathematical analyses. The theoretical analyses are verified by performing Monte Carlo simulations. First, we study the cooperative relaying in the Two-Way Decode-and-Forward (DF) and multi-relay DF scheme for a secondary system to obtain spectrum access along with a primary system. In particular, we proposed the Two-Way DF scheme with Energy Harvesting, and the Two-Way DF Non-orthogonal Multiple Access (NOMA) scheme with digital network coding. Besides, we also investigate the wireless systems with multi-relay; the best relay selection is presented to optimize the effect of the proposed scheme. The transmission protocols of the proposed schemes EHAF (Energy Harvesting Amplify and Forward) and EHDF (Energy Harvesting Decode and Forward) are compared together in the same environment and in term of outage probability. Hence, with the obtained results, we conclude that the proposed schemes improve the performance of the wireless cooperative relaying systems, particularly their throughput. Second, we focus on investigating the NOMA technology and proposing the optimal solutions (protocols) to advance the data rate and to ensure the Quality of Service (QoS) for the users in the next generation of wireless communications. In this thesis, we propose a Two-Way DF NOMA scheme (called a TWNOMA protocol) in which an intermediate relay helps two source nodes to communicate with each other. Simulation and analysis results show that the proposed protocol TWNOMA is improving the data rate when comparing with a conventional Two-Way scheme using digital network coding (DNC) (called a TWDNC protocol), Two-Way scheme without using DNC (called a TWNDNC protocol) and Two-Way scheme in amplify-and-forward(AF) relay systems (called a TWANC protocol). Finally, we considered the combination of the NOMA and physical layer security (PLS) in the Underlay Cooperative Cognitive Network (UCCN). The best relay selection strategy is investigated, which uses the NOMA and considers the PLS to enhance the transmission efficiency and secrecy of the new generation wireless networks.V této dizertační práci je provedena studie nových přenosových protokolů pro různé bezdrátové síťové systémy. S využitím matematické analýzy jsme analyzovali a vyhodnotili efektivitu přenosu z hlediska pravděpodobnosti výpadku přes Rayleighův kanál. Teoretické analýzy jsou ověřeny provedenými simulacemi metodou Monte Carlo. Nejprve došlo ke studii kooperativního přenosu ve dvoucestném dekóduj-a-předej (Two-Way Decode-and-Forward–TWDF) a vícecestném DF schématu s větším počtem přenosových uzlů pro sekundární systém, kdy takto byl získán přístup ke spektru spolu s primárním systémem. Konkrétně jsme navrhli dvoucestné DF schéma se získáváním energie a dvoucestné DF neortogonální schéma s mnohonásobným přístupem (Non-orthogonal Multiple Access–NOMA) s digitálním síťovým kódováním. Kromě toho rovněž zkoumáme bezdrátové systémy s větším počtem přenosových uzlů, kde je přítomen výběr nejlepšího přenosového uzlu pro optimalizaci efektivnosti navrženého schématu. Přenosové protokoly navržených schémat EHAF (Energy Harvesting Amplify and Forward) a EHDF(Energy Harvesting Decode and Forward) jsou společně porovnány v identickém prostředí z pohledu pravděpodobnosti výpadku. Následně, na základě získaných výsledků, jsme dospěli k závěru, že navržená schémata vylepšují výkonnost bezdrátových kooperativních systémů, konkrétně jejich propustnost. Dále jsme se zaměřili na zkoumání NOMA technologie a navrhli optimální řešení (protokoly) pro urychlení datového přenosu a zajištění QoS v další generaci bezdrátových komunikací. V této práci jsme navrhli dvoucestné DF NOMA schéma (nazýváno jako TWNOMA protokol), ve kterém mezilehlý přenosový uzel napomáhá dvěma zdrojovým uzlům komunikovat mezi sebou. Výsledky simulace a analýzy ukazují, že navržený protokol TWNOMA vylepšuje dosaženou přenosovou rychlost v porovnání s konvenčním dvoucestným schématem používajícím DNC (TWDNC protokol), dvoucestným schématem bez použití DNC (TWNDNC protokol) a dvoucestným schématem v zesil-a-předej (amplify-and-forward) přenosových systémech (TWANC protokol). Nakonec jsme zvážili využití kombinace NOMA a zabezpečení fyzické vrstvy (Physical Layer Security–PLS) v podpůrné kooperativní kognitivní síti (Underlay Cooperative Cognitive Network–UCCN). Zde je zde zkoumán výběr nejlepšího přenosového uzlu, který užívá NOMA a bere v úvahu PLS pro efektivnější přenos a zabezpečení nové generace bezdrátových sítí.440 - Katedra telekomunikační technikyvyhově

    Application and Theory of Multimedia Signal Processing Using Machine Learning or Advanced Methods

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    This Special Issue is a book composed by collecting documents published through peer review on the research of various advanced technologies related to applications and theories of signal processing for multimedia systems using ML or advanced methods. Multimedia signals include image, video, audio, character recognition and optimization of communication channels for networks. The specific contents included in this book are data hiding, encryption, object detection, image classification, and character recognition. Academics and colleagues who are interested in these topics will find it interesting to read

    The University Defence Research Collaboration In Signal Processing

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    This chapter describes the development of algorithms for automatic detection of anomalies from multi-dimensional, undersampled and incomplete datasets. The challenge in this work is to identify and classify behaviours as normal or abnormal, safe or threatening, from an irregular and often heterogeneous sensor network. Many defence and civilian applications can be modelled as complex networks of interconnected nodes with unknown or uncertain spatio-temporal relations. The behavior of such heterogeneous networks can exhibit dynamic properties, reflecting evolution in both network structure (new nodes appearing and existing nodes disappearing), as well as inter-node relations. The UDRC work has addressed not only the detection of anomalies, but also the identification of their nature and their statistical characteristics. Normal patterns and changes in behavior have been incorporated to provide an acceptable balance between true positive rate, false positive rate, performance and computational cost. Data quality measures have been used to ensure the models of normality are not corrupted by unreliable and ambiguous data. The context for the activity of each node in complex networks offers an even more efficient anomaly detection mechanism. This has allowed the development of efficient approaches which not only detect anomalies but which also go on to classify their behaviour

    The University Defence Research Collaboration In Signal Processing: 2013-2018

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    Signal processing is an enabling technology crucial to all areas of defence and security. It is called for whenever humans and autonomous systems are required to interpret data (i.e. the signal) output from sensors. This leads to the production of the intelligence on which military outcomes depend. Signal processing should be timely, accurate and suited to the decisions to be made. When performed well it is critical, battle-winning and probably the most important weapon which you’ve never heard of. With the plethora of sensors and data sources that are emerging in the future network-enabled battlespace, sensing is becoming ubiquitous. This makes signal processing more complicated but also brings great opportunities. The second phase of the University Defence Research Collaboration in Signal Processing was set up to meet these complex problems head-on while taking advantage of the opportunities. Its unique structure combines two multi-disciplinary academic consortia, in which many researchers can approach different aspects of a problem, with baked-in industrial collaboration enabling early commercial exploitation. This phase of the UDRC will have been running for 5 years by the time it completes in March 2018, with remarkable results. This book aims to present those accomplishments and advances in a style accessible to stakeholders, collaborators and exploiters

    Schweizerische Präsenz an internationalen Forschungsfronten 1999

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    Winterhager M, Schwechheimer H. Schweizerische Präsenz an internationalen Forschungsfronten 1999. Center for Science and Technology Studies. Vol 2002,8. Bern: CEST; 2002.Ziel der vorliegenden Untersuchung ist die Identifikation und Analyse der wichtigsten Forschungsfronten, an denen in der Schweiz tätige Forschende 1999 beteiligt waren. Schwerpunkte schweizerischer Forschungsaktivität werden durch ein bibliometrisches Profil auf der Grundlage einer Ko-Zitationsanalyse transparent gemacht. Die mit der Ko-Zitationsanalyse identifizierten Forschungsfronten liefern eine Abbildung der aktuellen Forschungslandschaft, die allein auf der Auswertung der Ströme formaler Kommunikation (Publikationen und Zitationen) beruht. In diesem Sinne ist das Verfahren unabhängig von bestehenden Klassifikationsschemata, disziplinären Zuordnungen und subjektiven Sichtweisen einzelner Experten. Es nutzt lediglich die durch die publizierenden Forscherinnen und Forscher selbst realisierten kognitiven Bezüge, um aktuelle Forschungsfronten zu identifizieren und ihre Relationen zueinander darzustellen. Der Bericht dokumentiert zunächst das Ergebnis der Suche nach den Forschungsfronten mit schweizerischer Beteiligung. Als Datenbasis wurde eine Ko-Zitationsanalyse des Jahrgangs 1999 des Science Citation Index Expanded und des Social Sciences Citation Index herangezogen. Diese Datenbasis besteht aus insgesamt 22942 Forschungsfronten aus allen disziplinären Bereichen. Die Forschungsfronten werden ohne vorgängige disziplinäre Kategorisierungen generiert und sind daher in besonderer Weise geeignet, interdisziplinäre Entwicklungen abzubilden. Aus dem Gesamtdatenbestand aller Fronten des Jahrgangs 1999 wurden diejenigen 2.404 ausgewählt, in deren Kern mindestens eine Publikation schweizerischen Ursprungs enthalten ist
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