Hypercyclic and topologically mixing cosine functions on Banach spaces

Our first aim in this paper is to give sufficient conditions for the hypercyclicity and topological mixing of a strongly continuous cosine function. We apply these results to study the cosine function associated to translation groups. We also prove that every separable infinite dimensional complex Banach space admits a topologically mixing uniformly continuous cosine family.

     

A Review of Audio Fingerprinting

An audio fingerprint is a compact content-based signature that summarizes an audio recording. Audio Fingerprinting technologies have attracted attention since they allow the identification of audio independently of its format and without the need of meta-data or watermark embedding. Other uses of fingerprinting include: integrity verification, watermark support and content-based audio retrieval. The different approaches to fingerprinting have been described with different rationales and terminology: Pattern matching, Multimedia (Music) Information Retrieval or Cryptography (Robust Hashing). In this paper, we review different techniques describing its functional blocks as parts of a common, unified framework. Pedro Cano received a B.Sc and M. Sc. Degree in Electrical Engineering from the Universitat Politècnica de Catalunya in 1999. In 1997, he joined the Music Technology Group of the Universitat Pompeu Fabra where he is currently pursuing his Ph.D. on Content-based Audio Identification. He has been assistant professor in the Department of Technologies of the Universitat Pompeu Fabra since 1999. His research interests and recent work include: signal processing for music applications, within a real-time voice morphing system for karaoke applications, pattern matching and information retrieval, specifically content-based audio identification. Eloi Batlle received his M.S. degree in electronic engineering in 1995 from the Politechnical University of Catalunya in Barcelona, Spain. He then joined the Signal Processing Group at the same university where he was working on robust speech recognition. He received a PhD on this subject in 1999. While he was a PhD student he also worked as a researcher at the Telecom Italia Lab during 1997. In 2000 he joined the Audiovisual Institute (a part of the Pompeu Fabra University). Currently he is a member of the Music Technology Group of the same Institute where he leads several reseach projects on music identification and similarity. In 2000 he also joined the Department of Technologies of the Pompeu Fabra University and he teaches several subjects to undergraduate and graduate students. From 2001 he is the Deputy Director of this Department. His research interests include information theory, music similary, statistical signal processing and pattern recognition. Ton Kalker was born in The Netherlands in 1956. He received his M.S. degree in mathematics in 1979 from the University of Leiden, The Netherlands. From 1979 until 1983, while he was a Ph.D. candidate, he worked as a Research Assistant at the University of Leiden. From 1983 until December 1985 he worked as a lecturer at the Computer Science Department of the Technical University of Delft. In January 1986 he received his Ph.D. degree in Mathematics. In December 1985 he joined the Philips Research Laboratories Eindhoven. Until January 1990 he worked in the field of Computer Aided Design. He specialized in (semi) automatic tools for system verification. Currently he is a member of the Processing and Architectures for Content MANagement group (PACMAN) of Philips Research, where he is working on security of multimedia content, with an emphasis on watermarking and fingerprinting for video and audio. In November 1999 he became a part-time professor in the Signal Processing Systems group of Jan Bergmans in the area of ‘signal processing methods for data protection’. He is a Fellow of the IEEE for his contributions to practical applications of watermarking, in particular watermarking for DVD-Video copy protection. His other research interests include wavelets, multirate signal processing, motion estimation, psycho physics, digital video compression and medical image processing. Jaap Haitsma was born in 1974 in Easterein, the Netherlands. He received his B.Sc. in Electronic Engineering from the Noordelijke Hogeschool Leeuwarden in 1997. He did his thesis in 1997 at the Philips Research Laboratories in Redhill, England, on the topic of: “Colour Management for Liquid Crystal Displays”. Currently he is with the Philips Research Laboratories, Eindhoven, the Netherlands, where he has been doing research into digital watermarking and fingerprinting of audio and video since late 1997. From 1999 to 2002 he was also a part-time student at the Technical University of Eindhoven, where he obtained his M.Sc. in Electronic Engineering. His areas of interest include digital signal processing, database search algorithms and software engineering.     

Finite element method applied to the quenching of steel cylinders using a multi-phase constitutive model

Heat treatment processes are usually employed to control the mechanical properties of steels and quenching is one of the most common treatments. This article deals with the modeling and simulation of quenching in steel cylinders using a multi-phase constitutive model. Finite element method is employed for spatial discretization. Numerical simulations are carried out by considering an iterative process associated with the operator split technique. Initially, a verification procedure is of concern establishing a comparison between numerical and experimental data, presenting a good agreement. Afterward, notched steel cylinders are treated evaluating the influence of notches in quenched pieces. Temperature, phase transformations and stresses are monitored during the quenching in order to give a general idea of the thermomechanical behavior of the process.     

On Quantales and Spectra of C*-Algebras

We study properties of the quantale spectrum MaxA of an arbitrary unital C^*-algebra A. In particular we show that the spatialization of MaxA with respect to one of the notions of spatiality in the literature yields the locale of closed ideals of A when A is commutative. We study under general conditions functors with this property, in addition requiring that colimits be preserved, and we conclude in this case that the spectrum of A necessarily coincides with the locale of closed ideals of the commutative reflection of A. Finally, we address functorial properties of Max, namely studying (non-)preservation of limits and colimits. Although Max is not an equivalence of categories, therefore not providing a direct generalization of Gelfand duality to the noncommutative case, it is a faithful complete invariant of unital C^*-algebras.     

An investigation of the Lewis acid mediated 1,3-dipolar cycloaddition between N-benzyl-C-(2-pyridyl)nitrone and allylic alcohol. Direct entry to isoxazolidinyl C-nucleosides

The cycloaddition reaction of N-benzyl C-(2-pyridyl) nitrone with allylic alcohol has been carried out to obtain the corresponding 2-benzyl-3-(2-pyridyl)-5-hydroxymethylisoxazolidine. The influence of Lewis acids in the reaction has been studied and a complete 3,5-regioselectivity and cis diastereoselectivity was observed when the reaction was carried out with 1.0 equiv of AgOTf, [Ag(OClO3)(PPh2Me)] or Zn(OTf)2. Insight into the mechanism of the reaction has been obtained by isolating and characterizing (X-ray) the intermediate complexes. Also, a model based on both experimental and theoretical results is proposed.     

Photochemical [2 + 2] cycloaddition of acetylene to chiral 2(5H)-furanones

The [2 + 2] photocycloaddition of acetylene to chiral 2(5H)-furanones was investigated. The influence on the chemical yield and facial diastereoselectivity of the substituent at the stereogenic center and also the effect of a 4-methyl group were evaluated. A mechanistic proposal based on a simple theoretical conformational analysis is presented. Using a C(2)-symmetric bis(lactone) as the substrate, a diastereomeric excess higher than 98% was found.     

Straightforward asymmetric entry to highly functionalized 3-substituted 3-hydroxy-beta-lactams via Baylis-Hillman or bromoallylation reactions

The reaction of various activated vinyl systems, including 2-cyclopenten-1-one, with enantiopure azetidine-2,3-diones 1 was promoted by DABCO to afford the corresponding optically pure Baylis-Hillman adducts 2 without detectable epimerization. However, the reaction of alpha-keto lactams 1 with but-3-yn-2-one was not as successful, giving the corresponding beta-halo Baylis-Hillman adduct in low yield. Metal-mediated bromoallylation reaction between 2,3-dibromopropene and azetidine-2,3-diones 1 was investigated in aqueous media. Surprisingly, indium was unable to promote the bromoallylation reaction of alpha-keto lactams 1, but the Sn-Hf(4)Cl-promoted bromoallylation of ketones 1 proceeded efficiently to achieve bromohomoallyl alcohols 5 as single diastereomers. On this basis, simple and fast protocols for the asymmetric synthesis of the potentially bioactive 3-substituted 3-hydroxy-beta-lactam moiety were developed.