A Hardware Oriented Method to Generate and Evaluate Nonlinear Interleaved Sequences with Desired properties

It is well known that the combinatorial structure, algebraic structure and D-transform based method render the nonlinear sequences with good autocorrelation function (ACF) and great linear complexity (LC). However, “all sequences” are not equal even if they are “born” by the same method! In this paper the big inequalities regarding LC of these sequences are shown based on a hardware oriented method (D-transform). In order to get the right sequences some more extensive simulations and trade off are needed. That is why this paper is represented here with above Title. Keywords: cryptography, mobile communications, security, watermarking, D-transfor

NONLINEAR OPERATORS FOR IMAGE PROCESSING: DESIGN, IMPLEMENTATION AND MODELING TECHNIQUES FOR POWER ESTIMATION

1998/1999Negli ultimi anni passati le applicazioni multimediali hanno visto uno sviluppo notevole, trovando applicazione in un gran numero di campi. Applicazioni come video conferenze, diagnostica medica, telefonia mobile e applicazioni militari necessitano il trattamento di una gran mole di dati ad alta velocità. Pertanto, l'elaborazione di immagini e di dati vocali è molto importante ed è stata oggetto di numerosi sforzi, nel tentativo di trovare algoritmi sempre più veloci ed efficaci. Tra gli algoritmi proposti, noi crediamo che gli operatori razionali svolgano un ruolo molto importante, grazie alla loro versatilità ed efficacia nell'elaborazione di dati. Negli ultimi anni sono stati proposti diversi algoritmi, dimostrando che questi operatori possono essere molto vantaggiosi in diverse applicazioni, producendo buoni risultati. Lo scopo di questo lavoro è di realizzare alcuni di questi algoritmi e, quindi, dimostrare che i filtri razionali, in particolare, possono essere realizzati senza ricorrere a sistemi di grandi dimensioni e possono raggiungere frequenze operative molto alte. Una volta che il blocco fondamentale di un sistema basato su operatori razionali sia stato realizzato, esso pu6 essere riusato con successo in molte altre applicazioni. Dal punto di vista del progettista, è importante avere uno schema generale di studio, che lo renda capace di studiare le varie configurazioni del sistema da realizzare e di analizzare i compromessi tra le variabili di progetto. In particolare, per soddisfare l'esigenza di metodi versatili per la stima della potenza, abbiamo sviluppato una tecnica di macro modellizazione che permette al progettista di stimare velocemente ed accuratamente la potenza dissipata da un circuito. La tesi è organizzata come segue: Nel Capitolo 1 alcuni sono presentati alcuni algoritmi studiati per la realizzazione. Ne viene data solo una veloce descrizione, lasciando comunque al lettore interessato dei riferimenti bibliografici. Nel Capitolo 2 vengono discusse le architetture fondamentali usate per la realizzazione. Principalmente sono state usate architetture a pipeline, ma viene data anche una descrizione degli approcci oggigiorno disponibili per l'ottimizzazione delle temporizzazioni. Nel Capitolo 3 sono presentate le realizzazioni di due sistemi studiati per questa tesi. Gli approcci seguiti si basano su ASIC e FPGA. Richiedono tecniche e soluzioni diverse per il progetto del sistema, per cui é interessante vedere cosa pu6 essere fatto nei due casi. Infine, nel Capitolo 4, descriviamo la nostra tecnica di macro modellizazione per la stima di potenza, dando una breve visione delle tecniche finora proposte e facendo vedere quali sono i vantaggi che il nostro metodo comporta per il progetto.In the past few years, multimedia application have been growing very fast, being applied to a large variety of fields. Applications like video conference, medical diagnostic, mobile phones, military applications require to handle large amount of data at high rate. Images as well as voice data processing are therefore very important and they have been subjected to a lot of efforts in order to find always faster and effective algorithms. Among image processing algorithms, we believe that rational operators assume an important role, due to their versatility and effectiveness in data processing. In the last years, several algorithms have been proposed, demonstrating that these operators can be very suitable in different applications with very good results. The aim of this work is to implement some of these algorithm and, therefore, demonstrate that rational filters, in particular, can be implemented without requiring large sized systems and they can operate at very high frequencies. Once the basic building block of a rational based system has been implemented, it can be successfully reused in many other applications. From the designer point of view, it is important to have a general framework, which makes it able to study various configurations of the system to be implemented and analyse the trade-off among the design variables. In particular, to meet the need far versatile tools far power estimation, we developed a new macro modelling technique, which allows the designer to estimate the power dissipated by a circuit quickly and accurately. The thesis is organized as follows: In chapter 1 we present some of the algorithms which have been studied for implementation. Only a brief overview is given, leaving to the interested reader some references in literature. In chapter 2 we discuss the basic architectures used for the implementations. Pipelined structures have been mainly used for this thesis, but an overview of the nowaday available approaches for timing optimization is presented. In chapter 3 we present two of the implementation designed for this thesis. The approaches followed are ASIC driven and FPGA drive. They require different techniques and different solution for the design of the system, therefore it is interesting to see what can be done in both the cases. Finally, in chapter 4, we describe our macro modelling techniques for power estimation, giving a brief overview of the up to now proposed techniques and showing the advantages our method brings to the design.XII Ciclo1969Versione digitalizzata della tesi di dottorato cartacea

Investigating and manipulating the reaction mechanism of reductive carboxylases

Efficient capture and conversion of atmospheric carbon dioxide (CO2) is a prerequisite to develop a carbon-neutral, circular future economy. Carbon fixation is the process by which inorganic carbon is fixed into biomass. In Nature, enzymes called caboxlyases are able to capture atmospheric carbon dioxide under mild conditions and catalyze its incorporation into organic molecules. It is estimated that 400 Gt of CO2 are fixed annually solely by the enzyme ribulose-1,5-bisphophate-carboxylase/oxygenase (RuBisCO), the key enzyme of photosynthesis. In comparison, CO2 utilization by chemical industries accounts for only 0.1 Gt of carbon annually and utilizes pressurized CO2, which emphasizes our need to understand the molecular mechanism that allow carboxylases to selectively interact with a CO2 at atmospheric concentrations (0.04% vol) during catalysis. Enoyl-CoA carboxylases/reductases (ECRs) represent the fastest carboxylases known to date and is, in contrast to RuBisCO, completely specific for CO2. These enzymes catalyze the reductive carboxylation of enoyl-CoAs by oxidizing one equivalent of NADPH. ECRs represent a good case study for the understanding of the CO2 chemistry that carboxylases use. In this work, we try to gain a better understanding of the underlying catalytic principles that enable ECRs to achieve high catalytic rates. Initially we focus on understanding how the precise interaction between protein and CO2 takes place at the active site of ECRs. We were able to identify and assign a function to four conserved amino acid residues found at the active site of ECRs. Three residues are responsible for the precise positioning of CO2 for nucleophilic attack by the enolate intermediate. Additionally, one residue is able to shield the active site from water thereby preventing the irreversible protonation of the enolate. These two mechanistic principles are at the base of the efficient carboxylation in ECRs. The following chapter briefly describes how the enzyme is able to accept other electrophiles than CO2. We show that ECRs can utilize formaldehyde as an alternative electrophile to CO2 thereby yielding beta-hydroxy thioesters. The exquisite stereospecificity together with the vast range of small electrophiles make ECR a potential biocatalyst for the production of various α-substituted thioesters. The last two chapters of this work focus on the structural aspects of ECR catalysis. We were able to obtain four new crystal structures of an ECR from Kitasatospora setae and to propose a model for the catalytic cycle of this enzyme. We show that the communication between and within the dimers that compose the functional homotetramer is crucial for the fast catalytic rates observed in this ECR. A separate study aims at developing an in vivo directed evolution screen to improve the catalytic properties of an ECR from Burkholderia ambifaria. Our approach yields an evolved variant, with mutations distant from the active site. The observed improved catalytic supports the importance of the residues for the catalytic rate. Both studies revealed the importance of the residues at the interface of the ECR monomers by their impact on catalytic rates of this enzyme

Homogeneous Dynamics and Number Theory

The theory of flows on homogeneous spaces of Lie groups has emerged as a distinct, rapidly advancing subject over the last few decades incorporating ergodic theory, geometry and number theory. The workshop showcased the latest advances in the subject as well as a wide range of applications

Hidden Markov Models

Hidden Markov Models (HMMs), although known for decades, have made a big career nowadays and are still in state of development. This book presents theoretical issues and a variety of HMMs applications in speech recognition and synthesis, medicine, neurosciences, computational biology, bioinformatics, seismology, environment protection and engineering. I hope that the reader will find this book useful and helpful for their own research

FIAS Scientific Report 2011

In the year 2010 the Frankfurt Institute for Advanced Studies has successfully continued to follow its agenda to pursue theoretical research in the natural sciences. As stipulated in its charter, FIAS closely collaborates with extramural research institutions, like the Max Planck Institute for Brain Research in Frankfurt and the GSI Helmholtz Center for Heavy Ion Research, Darmstadt and with research groups at the science departments of Goethe University. The institute also engages in the training of young researchers and the education of doctoral students. This Annual Report documents how these goals have been pursued in the year 2010. Notable events in the scientific life of the Institute will be presented, e.g., teaching activities in the framework of the Frankfurt International Graduate School for Science (FIGSS), colloquium schedules, conferences organized by FIAS, and a full bibliography of publications by authors affiliated with FIAS. The main part of the Report consists of short one-page summaries describing the scientific progress reached in individual research projects in the year 2010..

Afar, Ethiopia: a local seismic survey

A network of four independently-recording seismic stations was operated by the University of Durham in South-Central Afar during 1973 and 1974. Each station consisted of a three-component set of seismometers, whose signals were recorded on to magnetic tape. This study concerns local earthquakes recorded from February to September, 1974.250 earthquakes were located from relative arrival times of P and S phases using an optimized, laterally homogeneous, 4-layer structural model. Upper crustal P-wave velocities are found to be 4.4±0.2 km s(^-1) (0 to 4.5 km depth) and 6.2± 0.1 km s(^-1) (4.5 to 11 km). Deeper structure is poorly constrained. Anomalous upper mantle exists, with low seismic velocity (Vp about 7.4 km s(^-1)) and raised Poisson's ratio (0.31). S(_n) is transmitted, 8.0 km s(^-1) upper mantle cannot exist above about 43 km depth. Earthquake focal depths within Afar do not exceed 5 km. Epicentres correlate well with Recent axial volcanism. Spatial epicentral patterns reflect intense regional NW-SE extensional faulting. One line of epicentres shows the NNE-SSW trend of the Main Ethiopian rift. Focal mechanisms are very poorly constrained, but are consistent with NW-SE strike-slip or normal faulting, or with NE-SW dextral transcurrent faulting. Signal duration magnitude and Richter local magnitude scales are defined for Afar, Frequency-magnitude b-coefficient values are 0.87+0.05, The three-component records are polarization filtered, a technique previously applied only to teleseisms. The performance of the filters is discussed. Azimuths and apparent angles of incidence of events are determined from their first arrivals at a single recording station. Hypocentres are then obtained by ray tracing. Earthquake frequency spectra are computed through the fast Fourier transform. The spectra are dominated by the effects of the superficial crust below the receivers. Crustal transfer ratios are discussed. Increased attenuation is demonstrated below the Tendaho graben. Seismic source parameters are calculated using BRUNE's (1970) method. All results are consistent with diffuse NE-SW crustal extension. It is concluded that well-defined spreading axes do not yet exist