9,101 research outputs found
在有限區間向量型Sturm-Liouville方程式的唯一性定理
No full text博士關於定義在區間的非對稱形Sturm-Liouville 微分方程式的反問題研究及學習，Yurko ( [24] , 2006)利用Weyl矩陣，提出了矩陣邊界值問題的反問題有唯一性的定理。 在本篇論文，首先；對於Sturm-Liouville矩陣微分方程式含有一般的邊界條件的反問題，我們將証明ㄧ般的h1 , H1，亦可得到Q(x)有唯一性。利用矩陣型式邊界值反問題的唯一性，我們主要工作是在向量微分方程式邊界值反問題上，探求向量頻譜(spectral sets)與位階函數Q(x)唯一性的關係。 對於h1 = H1 = In ,我們找出某些個頻譜就可以決定Q(x)了。而若為一對稱矩陣或對角化矩陣，則個別僅需某些頻譜集合即可。 對於一般的h1 , H1，我們也獲得了一些相關的結果。Inverse spectral problems are studied for the non-self-adjoint matrix Sturm-Liouville differential equation on a finite interval. Using Weyl function, Yurko([24],2006) solved the inverse spectral problem for the matrix Sturm-Liouville operator on a finite interval with the boundary value problem L(Q(x), h, H ).
At first, in this thesis, we try to solve the uniqueness theorem of the matrix-valued boundary value problem for arbitrary matrices h1 , h0 , H1 , H0 with the general boundary conditions. By the uniqueness theorem of L(Q(x),h1 , h0 , H1 , H0) described as above, our main work is to find those relations between spectra and potential Q(x) for the vectorial Sturm-Liouville differential equation.
For h1 = H1 = In , we will give some characteristic functions corresponding to spectra to determine the Weyl matrix and to prove the uniqueness theorem. Furthermore, we also prove the uniqueness theorems for the vectorial Sturm-Liouville operators with real symmetric potential or real diagonal potential by given some spectra, respectively. We also obtain some results for arbitrary matrices h1 and H1.Chapter 1. Introduction
1.1 Sturm-Liouville operators on a finite interval
.......... 3
1.2 Vectorial Sturm-Liouville equation on a finite
interval ...........6
1.3 The Weyl matrix .............. 9
1.4 Sturm-Liouville equation on a graph ...... 11
Chapter 2. Uniqueness of the potential function for vectorial Sturm-Liouville equation on a finite interval
2.1 Preliminaries ............19
2.2 Main results ..............21
Chapter 3. Uniqueness theorem for the vectorial Sturm-Liouville equation with general boundary conditions
3.1 Introduction .................... 31
3.2 Preliminaries ............... 32
3.3 Main results .................... 38
References .............................50學號: 892150052, 學年度: 10
Local curvature-dimension condition implies measure-contraction property
No full textAbstractWe prove that for non-branching metric measure spaces the local curvature condition CDloc(K,N) implies the global version of MCP(K,N). The curvature condition CD(K,N) introduced by the second author and also studied by Lott and Villani is the generalization to metric measure space of lower bounds on Ricci curvature together with upper bounds on the dimension. This paper is the following step of Bacher and Sturm (2010) [1] where it is shown that CDloc(K,N) is equivalent to a global condition CD⁎(K,N), slightly weaker than the usual CD(K,N). It is worth pointing out that our result implies sharp Bishop–Gromov volume growth inequality and sharp Poincaré inequality
Thomas Sturm, Research Scholar al Max Planck Institute for the History of Science
No full textFormat com a filòsof, però amb un fort interès per la història de la ciència, Thomas Sturm és un especialista en filosofia moderna i les relacions entre la història i la filosofia de la ciència. Des de 2005 és investigador del "Max Planck Institute for the History of Science", a Berlín, on ha treballat en el projecte "Perceptual Illusions in the Dynamics of Psychological Research". Sturm va visitar el Centre d'Estudis de la Ciència de la UAB (CEHIC), on va oferir una conferència sobre les il·lusions perceptives i les relacions entre psicologia i epistemologia.Formado en el ámbito de la filosofía, pero con un fuerte interés por la historia de la ciencia, Thomas Sturm es un especialista en filosofía moderna y las relaciones entre la historia y la filosofía de la ciencia. Desde 2005 es investigador del Max Plack Institute for the History of Science, en Berlín, donde ha trabajado en el proyecto Perceptual Illusions in the Dynamics of Psychological Research. Sturm visitó el Centro de Estudios en Historia de la Ciencia de la UAB (CEHIC), donde ofreció una conferencia sobre las ilusiones preceptivas y las relaciones entre psicología y epistemología.Trained as a philosopher but with strong interests in the history of science, Thomas Sturm is a specialist in the field of modern philosophy and the relations between history and philosophy of science, with a particular emphasis on the analysis of psychological research. Since 2005, he is a research scholar at the Max Planck Institute for the History of Science in Berlin, where he has been working on a project entitled "Perceptual Illusions in the Dynamics of Psychological Research". Sturm visited the UAB Center for the History of Science (CEHIC), where he led a seminar on perceptive illusions and relations between psychology and epistemology
Selfadjoint and m Sectorial Extensions of Sturm–Liouville Operators
No full textThe self-adjoint and m-sectorial extensions of coercive Sturm–Liouville operators are characterised, under minimal smoothness conditions on the coefficients of the differential expression
Thomas Sturm, Research Scholar al Max Planck Institute for the History of Science
No full textFormat com a filòsof, però amb un fort interès per la història de la ciència, Thomas Sturm és un especialista en filosofia moderna i les relacions entre la història i la filosofia de la ciència. Des de 2005 és investigador del "Max Planck Institute for the History of Science", a Berlín, on ha treballat en el projecte "Perceptual Illusions in the Dynamics of Psychological Research". Sturm va visitar el Centre d'Estudis de la Ciència de la UAB (CEHIC), on va oferir una conferència sobre les il·lusions perceptives i les relacions entre psicologia i epistemologia
A study on Meligethes (Nitidulidae) species in Keszthely, 2002
No full textIn 2002 we examined when the Meligethes adults emerged from the wintering places and settled in the rape field. We wanted to know how many species within the genus Meligethes, when and in what proportion and rate appeared in oilseed rape as a feed plant. In our investigations we found the following species: Meligethes aeneus (Fabricius, 1775), M. coracinus (Sturm, 1845), M. viridescens (Fabricius, 1787), M. picipes (Sturm, 1845), M. nigrescens (Stephens, 1830), M. maurus (Sturm, 1845), M. atratus (Olivier, 1890), M. denticulatus (Heer, 1841), M. erythropus (Marsham, 1802)
Megaturbidite deposits in the Holocene basin fill of Lake Como (Southern Alps, Italy)
No full textFor the first time, limnogeological investigations have been carried out in Lake Como, the deepest lake of the Alps, combining a bathymetric survey (multibeam Simrad 3000) with a high-resolution seismic reflection study (single-channel 3.5 kHz sub-bottom profiler) and a coring campaign (gravity corer). This data set enables detailed characterization of the sedimentary subsurface in the western branch of the lake, the Como branch, which has a typical fjord morphology. This paper focuses on the deepest part of the Como branch (Argegno basin), in which up to 3.5-m-thick turbidite deposits are identified. The basin fill of the Como branch is characterized by well-layered draping and onlapping pelagic sediments that are locally affected by creeping and that are intercalated with mass-wasting deposits, in particular with two large debris-flow deposits evolving into megaturbidites in the deepest part of the basin. The multibeam data together with the acoustic-facies distributions and the volumes of these two major sedimentary deposits MT1 ( 3 × 106 m3) and MT2 ( 10.5 × 106 m3) indicate that they resulted from large slides at the northern tip of the Como branch along the steep slopes of a sub-lacustrine plateau. The estimated ages of these events, around the mid-12th (MT1) and early 6th (MT2) centuries, are extrapolated from mean sedimentation rates based on radiocarbon (14C) and radionuclide (137Cs) analyses from short cores in the Argegno basin. Possible trigger mechanisms leading to these catastrophic events in the Como branch include a combination of steep-slope overloading, with significant lake-level fluctuations related to Holocene climate change and/or earthquake shaking. The tentative age assignment places the age of both major mass movements near two other events: MT1 near the occurrence of a major earthquake in the Po Plain in 1222 AD (Intensity IX MCS, macroseismically derived magnitude 6.2) and MT2 near a megaturbidite triggered in 700 AD in a proglacial lake in southeastern Switzerland [Blass, A., Anselmetti, F., Grosjean, M., Sturm, M., 2005. The last 1300 years of environmental history in the sediments of Lake Sils (Engadine, Switzerland). Eclogae Geologicae Helvetiae 98, 319–332]. Since dangerous, tsunami-like waves (seiches) can be generated by large sub-aqueous landslides leading to such megaturbidites in this fjord-like basin, future studies are required: 1) to constrain the age of these catastrophic events; 2) to document the stabilities of the steep slopes in the Como branch, 3) to assess the expected frequency of such catastrophic events and 4) to model the propagation of large waves in the Como branch and their potential damage along the highly populated lake shore
M-matrix asymptotics for Sturm–Liouville problems on graphs
No full textAbstractWe consider a system formulation for Sturm–Liouville operators with formally self-adjoint boundary conditions on a graph. An M-matrix associated with the boundary value problem is defined and related to the matrix Prüfer angle associated with the system boundary value problem, and consequently with the boundary value problem on the graph. Asymptotics for the M-matrix are obtained as the eigenparameter tends to negative infinity. We show that the boundary conditions may be recovered, up to a unitary equivalence, from the M-matrix and that the M-matrix is a Herglotz function. This is the first in a series of papers devoted to the reconstruction of the Sturm–Liouville problem on a graph from its M-matrix
UWB orthogonal pulse design using Sturm–Liouville boundary value problem
No full textThe problem of designing UWB pulses which meet specific spectrum requirements is usually treated by filtering common pulses such as Gaussian doublets, modified Hermite polynomials and wavelets. When there is the need to have a number of orthogonal pulses (e.g., in a multiuser scenario), a naive approach is to filter all the members of an orthogonal set, which is likely to destroy their orthogonality property. In this paper, we study the design of a set of pulses that simultaneously satisfy the orthogonality property and spectrum requirements. Our design is based on the eigenfunctions of Sturm–Liouville boundary value problems. Indeed, we introduce Sturm–Liouville differential equations for which the eigenfunctions meet the FCC mask constraints. Computer simulation results show that all such waveforms occupy almost 55% of the allowed spectrum (utilization efficiency). A comparison of the proposed method with some conventional techniques of orthogonal UWB pulse generation will demonstrate the advantages of the new proposal.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Bart De Schutte
Architettura e significato del santuario della Madonna del Sorbo
No full textSorto sulle tracce di un nucleo fortificato medievale, il santuario della Madonna del Sorbo costituisce un’emergenza significativa del processo di antropizzazione di un territorio densamente stratificato. In un paesaggio rupestre di origine etrusca, poi colonizzato dalla conquista romana, nel cuore del sistema paesaggistico dell’ager veientanus, il complesso è arroccato su uno sperone roccioso, affiorando dalle pareti a strapiombo scavate nel complesso tufaceo dal fosso della Mola, con un dislivello di circa 200 m. tra il colle e la profonda gola di fondovalle. L’organismo architettonico denuncia la progressiva stratificazione strutturale, connessa alla particolare composizione morfologica e strategica della sua giacitura, attraendo, per le preponderanti caratteristiche rupestri e vedutistiche, l’attenzione di viaggiatori e incisori romantici, lasciando una memoria significativa anche nelle celebri Illustrated Excursions in Italy di Edward Lear (1846).
Sopra un articolato sistema di ambienti ipogei, in parte riconducibili all'età etrusca, si sarebbe innestato il primo nucleo difensivo, comprensivo di una chiesa rimaneggiata più volte, affidata nel 1425 alla cura dei Carmelitani dell’antica osservanza. Questi realizzarono sulle preesistenze un primitivo organismo conventuale, ampliato entro il 1487 contestualmente alla riconfigurazione della chiesa, dotata di navate laterali, nuovo fronte sporgente, e di un nucleo devozionale absidale ulteriormente valorizzato nel 1516 con l’erezione dell’altare maggiore sotto il patronato degli Orsini e della comunità di Formello. A fine secolo XVI viene ampliata e soprelevata la parallela stecca del “dormitorio”, raggiungendo una sostanziale definizione dei volumi conventuali, che necessitano tuttavia nel corso del Seicento di ripetuti massicci interventi di restauro e consolidamento, a rimedio di evidenti fragilità dei corpi di fabbrica, in particolare nelle zone di fondazione della lunga stecca orientale. Con l’incentivazione delle funzioni santuariali, si registrano contestualmente anche numerose operazioni decorative e di allestimenti liturgici effimeri e permanenti, tra cui la la riorganizzazione degli altari laterali affidata a Carlo Fontana dal cardinale Flavio Chigi nel 1682. Dalla fine del secolo XVII fino alla metà del successivo la macchina conventuale viene perfezionata negli aspetti funzionali e produttivi, con la riorganizzazione dell’intera superfice di pertinenza tramite recinzioni murate, terrazzamenti, cordonate, percorsi connettivi in parte ipogei, finalizzati alla saldatura dei manufatti più antichi col sistema di grotte interrate e con le nuove addizioni (granaio, fienile, torri colombaie, pozzo, campanile, loggiato frontale), guadagnando una definitiva configurazione formale destinata tuttavia a una durata limitata, a causa dell’ abbandono della struttura a partire dal 1782 e del suo progressivo deterioramento, culminato nei gravi crolli in chiesa del secondo dopoguerra (1963-66)
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