Control and chaos for vibro-impact and non-ideal oscillators

In the paper, we discuss dynamics of two kinds of mechanical systems. Initially, we consider vibro-impact systems which have many implementations in applied mechanics, ranging from drilling machinery and metal cutting processes to gear boxes. Moreover, from the point of view of dynamical systems, vibro-impact systems exhibit a rich variety of phenomena, particularly chaotic motion. In this paper, we review recent works on the dynamics of vibro-impact systems, focusing on chaotic motion and its control. The considered systems are a gear-rattling model and a smart damper to suppress chaotic motion. Furthermore, we investigate systems with non-ideal energy source, represented by a limited power supply. As an example of a non-ideal system, we analyse chaotic dynamics of the damped Duffing oscillator coupled to a rotor. Then, we show how to use a tuned liquid damper to control the attractors of this non-ideal oscillator.

BREAKING WAVES IN AN IDEAL QUARK GLUON PLASMA

We study the propagation of perturbations in the energy density in a quark gluon plasma. Expanding the Euler and continuity equations of relativistic hydrodynamics around equilibrium configurations we obtain a nonlinear differential equation called the breaking wave equation. We solve it numerically and follow the time-evolution of initially localized pulses. We find that, quite unexpectedly, these pulses live for a very long time (compared to the reaction time-scales) before breaking. In practice, they mimick the Korteweg-de Vries solitons. Their existence may have some observable consequences.

Fock space for fermion-like lattices and the linear Glauber model

The concept of Fock space representation is developed to deal with stochastic spin lattices written in terms of fermion operators. A density operator is introduced in order to follow in parallel the developments of the case of bosons in the literature. Some general conceptual quantities for spin lattices are then derived, including the notion of generating function and path integral via Grassmann variables. The formalism is used to derive the Liouvillian of the d-dimensional Linear Glauber dynamics in the Fock-space representation. Then the time evolution equations for the magnetization and the two-point correlation function are derived in terms of the number operator. (C) 2008 Elsevier B.V. All rights reserved.

U-curve: A branch-and-bound optimization algorithm for U-shaped cost functions on Boolean lattices applied to the feature selection problem

This paper presents the formulation of a combinatorial optimization problem with the following characteristics: (i) the search space is the power set of a finite set structured as a Boolean lattice; (ii) the cost function forms a U-shaped curve when applied to any lattice chain. This formulation applies for feature selection in the context of pattern recognition. The known approaches for this problem are branch-and-bound algorithms and heuristics that explore partially the search space. Branch-and-bound algorithms are equivalent to the full search, while heuristics are not. This paper presents a branch-and-bound algorithm that differs from the others known by exploring the lattice structure and the U-shaped chain curves of the search space. The main contribution of this paper is the architecture of this algorithm that is based on the representation and exploration of the search space by new lattice properties proven here. Several experiments, with well known public data, indicate the superiority of the proposed method to the sequential floating forward selection (SFFS), which is a popular heuristic that gives good results in very short computational time. In all experiments, the proposed method got better or equal results in similar or even smaller computational time. (C) 2009 Elsevier Ltd. All rights reserved.

Borgerlighetens ideal – arbetarnas verklighet. : En studie om Stora Tuna barnavårdsnämnds arbete 1903-1917.

Syftet med denna uppsats har varit att studera hur barnavårdsnämnden i Stora Tuna verkställde lagstiftningen om uppfostran åt vanartade och i sedligt avseende försummade barn. För att uppnå syftet med studien har barnavårdsnämndens ledamöter undersökts, lika så de anmälda barnen. Vad anmäldes de för, vilka blev konsekvenserna och vilka var det som stod för anmälningarna? Resultaten jämförs med tidigare forskning från andra platser. Huvudsakligen har protokoll från barnavårdsnämndens sammanträden mellan 1903 och 1917 använts för att besvara frågeställningarna.Resultatet visar att en klar majoritet av nämndens ledamöter representerade medelklassen eller överklassen, endast ett fåtal kom från arbetarklassen. Men de barn som anmäldes kom nästan uteslutande från arbetarklassen. Detta är något som den tidigare forskningen också framhåller. Pojkar anmäldes i betydligt högre utsträckning än flickor, men de flickor som anmäldes dömdes betydligt hårdare än pojkarna. Flickorna anmäldes främst på grund av de bristande hemförhållanden och påföljderna blev oftast att de skiljdes från hemmet till fosterhem eller till barnhem. Pojkarna anmäldes främst för stöld och den vanligaste påföljden blev en allvarlig varning. Polisen var den grupp som anmälde flest barn till nämnden.

Applicatiion of Almost ideal demand system for a pharmaceutical

This thesis is an application of the Almost Ideal Demand System approach of Deaton and Muellbauer,1980, for a particular pharmaceutical, Citalopram, in which GORMAN´s (1971) multi-stage budgeting approach is applied basically since it is one of the most useful approach in estimating demand for differentiated products. Citalopram is an antidepressant drug that is used in the treatment of major depression. As for most other pharmaceuticals whose the patent has expired, there exist branded and generic versions of Citalopram. This paper is aimed to define its demand system with two stage models for the branded version and five generic versions, and to show whether generic versions are able to compete with the branded version. I calculated the own price elasticities, and it made me possible to compare and make a conclusion about the consumers’ choices over the brand and generic drugs. Even though the models need for being developed with some additional variables, estimation results of models and uncompensated price elasticities indicated that the branded version has still power in the market, and generics are able to compete with lower prices. One important point that has to be taken into consideration is that the Swedish pharmaceutical market faced a reform on October 1, 2002, that aims to make consumer better informed about the price and decrease the overall expenditures for pharmaceuticals. Since there were not significantly enough generic sales to take into calculation before the reform, my paper covers sales after the reform.

Mastering : Undersökning av hur masteringsteknikers ideal och tidigare erfarenheter påverkar masteringsprocessen av inspelad musik

Genom att undersöka hur mycket av några masteringsteknikers personliga ideal och tidigare erfarenheter, med musikalisk bakgrund och smak, som hörs från masteringsprocesser av förelagda inspelningar av musik inom olika musikstilar är syftet att bidra med kunskap om hur mycket av de tidigare musikaliska influenserna en masteringstekniker tar med sig in i en masteringsprocess, och ses som användbar för fortsatt forskning inom ljud- och musikproduktion. Jag har låtit tre masteringstekniker under enskilda sessioner mastra tre ljudsekvenser, där jag även har observerat deras tillvägagångssätt, utfört intervjuer och sedan på egen hand granskat materialet genom att lyssna och titta på deras bearbetningar av ljuden. Slutligen har jag låtit fem vana lyssnare bedöma och kommentera mastringarna i form av en lyssningsundersökning. Utifrån observationerna, samtalen och min granskning tyder resultatet på att det personliga idealet och tidigare erfarenheten främst hörs i mastringar utförda av personer som är djupt rotade i sin favoritgenre och låter de idealen och arbetsmönstren även påverka mastringar inom främmande musikstilar.  

Vilhelm Ekelund och den fransk-italienska kultursfären : Några nedslag i de tidiga prosaverken - från Antikt ideal (1909) till Attiskt i fågelperspektiv (1919)

Vilhelm Ekelund och den fransk-italienska kultursfären: Några nedslag i de tidiga prosaverken – från Antikt ideal (1909) till Attiskt i fågelperspektiv (1919). (Vilhelm Ekelund and the French and Italian cultural heritage: A study of his early prose – from Antikt ideal (1909) to Attiskt i fågelperspektiv (1919)). The Swedish poet, essayist and aphorist Vilhelm Ekelund was not only influenced by German literature and philosophy, he also wrote extensive literary criticism on the subject of Romance language authors. This article discusses Ekelund’s relationship to some of the most influential French and Italian writers – as it can be seen in his work during the period 1909-1919. This relationship was ambiguous: he paid homage to French authors such as Montaigne, Montesquieu, Stendhal and Comte – as well as to the Italian poet and philosopher Leopardi – but he also severely criticized such distinguished writers as Baudelaire, Rousseau and Maupassant. One conclusion of this article is that the authors praised by Ekelund all venerate the Greek and Roman cultural heritage, whereas the despised novelists and poets were, in his opinion, either too “modern” or too “feminine” – both highly pejorative adjectives in the author’s terminology. It is also noted that Ekelund’s most ferocious attacks date from the first part of the decade, before he entered a more harmonic period with the works Metron (1918) and Attiskt i fågelperspektiv (1919).

DEN KOMMUNALA FÖRVALTNINGENSOM RATIONALISTISKT IDEAL- en fallstudie om styrning och handlingsutrymme inom skola,barnomsorg och miljö- och hälsoskydd

DEN KOMMUNALA FÖRVALTNINGEN SOM RATIONALISTISKT IDEAL - en fallstudie om styrning och handlingsutrymme inom skola, barnomsorg och miljö- och hälsoskydd.(The municipal authority as a rationalist ideal - a case-study on steering and scope for initiative within child-care, education and environmental departments.)A municipal authority is a considerable producer of services in the local community and iscommonly perceived as an important sector of the Swedish welfare system. One aspect of awell-functioning municipal organisation is that its administrative organs function efficiently.This study examines how activities in municipal administration are steered. The focus is on how different methods are used within a vertical hierarchical perspective to influence the actions of the participants and how the latter try to create space for action. To analyse the problem an ideal-type steering model is used.The study consists of three sections. In the first the research problem and the aims of the study are introduced as well as the methodological and theoretical approach. The result of the study is presented in the second section and in the third conclusions are drawn and discussed.The study shows that the perceptions of the participants involved regarding the possibilities of steering the everyday activities with the support of the methods studied differ on a number of points depending on the sector studied. When control of the various steering methods is distributed in different organisational units in the municipality a number of steering mechanisms operate side-by-side, sometimes in harmony and sometimes independently or in pure conflict with their goals. Steering leads to clear restrictions but there is clearlyroom for initiative, a ‘free-zone’ where the individual has room to act independently. Is it possible based on this study to state whether the ideal-type model functions in the way intended? On many accounts it would seem doubtful whether the effects of steering lead to beneficial effects for the activity. Rather it would seem that the effects of steeringsometimes function more or less randomly because the administration exists in a complexcontext in which the staff can be expected to have its own expectations and act in accordancewith them.

Condomínio comum e condomínio edilício: diferenças quanto ao rateio pela fração ideal e pela forma igualitária

Trata-se de uma pesquisa sobre a origem do Condomínio Comum e suas espécies, evoluindo para o estudo sobre Condomínio Edilício. O surgimento do Condomínio Edilício no Brasil, a evolução da propriedade, os direitos e deveres dos condôminos e a forma de cobrança das despesas condominiais com ênfase nas cobranças por fração ideal e pela forma igualitária com a demonstração de tabelas comparativas entre as duas formas de fixação da taxa condominial. Fez-se o estudo de ações movidas por proprietários de unidades em condomínios, pesquisas em doutrinas e literaturas na área do Direito Civil, consulta a sites especializados em questões administrativas sobre condomínios, pesquisas em boletins e periódicos da área de administração de condomínios. O objetivo principal deste trabalho é demonstrar a forma de cobrança da taxa condominial em alguns modelos de condomínios, em que alguns condôminos pagam a mais para usufruir dos mesmos serviços que os demais e a busca de seus direitos.

Condomínio comum e condomínio edilício:diferenças quanto ao rateio pela fração ideal e pela forma igualitária

Trata-se de uma pesquisa sobre a origem do Condomínio Comum e suas espécies, evoluindo para o estudo sobre Condomínio Edilício. O surgimento do Condomínio Edilício no Brasil, a evolução da propriedade, os direitos e deveres dos condôminos e a forma de cobrança das despesas condominiais com ênfase nas cobranças por fração ideal e pela forma igualitária com a demonstração de tabelas comparativas entre as duas formas de fixação da taxa condominial. Fez-se o estudo de ações movidas por proprietários de unidades em condomínios, pesquisas em doutrinas e literaturas na área do Direito Civil, consulta a sites especializados em questões administrativas sobre condomínios, pesquisas em boletins e periódicos da área de administração de condomínios. O objetivo principal deste trabalho é demonstrar a forma de cobrança da taxa condominial em alguns modelos de condomínios, em que alguns condôminos pagam a mais para usufruir dos mesmos serviços que os demais e a busca de seus direitos.

Cinemas de rua em Porto Alegre : do recreio ideal (1908) ao Açores (1974)

Este trabalho se propõe a investigar as diferentes formas e configurações que as salas de cinema de rua de Porto Alegre adotaram ao longo do século XX. Antecipa o estudo central uma analise do caráter arquitetônico e dos elementos tipo-morfológicos definidores do programa arquitetônico “sala de cinema”. Com base neste instrumental e seguindo a evolução histórica, dé cada a dé cada, o autor desenvolve então a análise das salas de cinema de rua de Porto Alegre.

Se In é um ideal finitamente gerado então I é um ideal finitamente gerado?

Suponhamos que M seja um ideal maximal de um domínio R e que alguma potência de M seja finitamente gerada. Vamos mostrar que M será finitamente gerado em cada um dos seguintes casos: i M tem altura um, ii R é inteiramente fechado e altura de M é 2, iii R K X,S é um domínio monóide sobre um corpo K, onde S S 0 é um monóide cancelativo e livre de torção, tal que i 1 iS e M é o ideal maximal gerado por Xs/s S . Estendemos os resultados anteriores aos ideais I de um anel reduzido R tal que RI é anel Noetheriano. Provamos que um anel reduzido R é Noetheriano se cada ideal primo de R possui uma potência que é finitamente gerada. Para cada d tal que 3 d , estabelecemos a existência de um domínio de integridade d-dimensional que possui um ideal maximal M não finitamente gerado, de altura d tal que M2 é 3-gerado.