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Search Results: 1 - 10 of 26372 matches for " Martin Sauter "
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Airborne Thermal Data Identifies Groundwater Discharge at the North-Western Coast of the Dead Sea
Ulf Mallast,Friedhelm Schwonke,Richard Gloaguen,Stefan Geyer,Martin Sauter,Christian Siebert
Remote Sensing , 2013, DOI: 10.3390/rs5126361
Abstract: A qualitative and quantitative monitoring of groundwater discharge was conducted based on an airborne thermal campaign undertaken along the north-western coast of the Dead Sea in January 2011 to contribute to the relatively scarce information on groundwater discharge to date in the region. The application of airborne thermal data exploits thermal contrasts that exist between discharging groundwater and background sea surface temperatures of the Dead Sea. Using these contrasts, 72 discharge sites were identified from which only 42 were known from previous in situ measurements undertaken at terrestrial springs by the Israel Hydrological Service. Six of these sites represent submarine springs and at a further 24 locations groundwater appears to seep through the sediment. Although the abundance of groundwater seepage sites suggests a significant, but so far unknown groundwater source, the main contribution appears to originate from terrestrial springs. In an attempt to provide a quantitative approach for terrestrial springs, a linear bootstrap regression model between in situ spring discharge and respective thermal discharge plumes (r 2 = 0.87 p < 0.001) is developed and presented here. While the results appear promising and could potentially be applied to derive discharge values at unmonitored sites, several influence factors need to be clarified before a robust and reliable model to efficiently derive a complete quantitative picture of groundwater discharge can be proposed.
A guided tour: Pollen tube orientation in flowering plants
Margret Sauter
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0329-6
Abstract: Sexual reproduction in flowering plants requires that two sperm cells are delivered to the embryo sac where double fertilization of an egg cell and of a central cell results in the formation of a diploid embryo and of the triploid nutritional endosperm tissue. The immobile male gametes are delivered to the immobile female gametophyte by a single cell, the pollen tube. The pollen tube must be able to germinate on a genetically appropriate stigma and it must be directed through the transmitting tract of the style from where it must target an ovule. Moreover, the pollen tube must enter the ovule at a defined opening, the micropyle, grow toward one of the two synergids and release the two sperm cells upon contact. This complex process requires recognition events with chemically based or physically supported cell-cell communication as well as directional cues for the growing pollen tube. A number of molecules and mechanisms have been implicated in pollen tube guidance which are summarized in this review.
Theatre – a Building, a Company, an Art Form: Terminology versus Reality. Teater – maja, trupp, kunstiliik: terminoloogia versus reaalsus
Willmar Sauter
Methis : Studia humaniora Estonica , 2009,
Abstract: Sada aastat, mis eesti kutselised teatrid on eksisteerinud, langeb kokku ajalooperioodiga, mille jooksul m iste teater t hendus j udis mitu korda muutuda. Kuigi me m tleme m istest teater kui millestki iidsest ja usaldusv rsest, kasutati seda varem v ga harva kunstiliigi t henduses. Enne 19. ja 20. sajandi vahetust teatrist isegi ei m eldud kui esteetilisest kategooriast. Teater vastas t nap eva t henduses lavale ning esines enamasti truppide nimedes, nagu n iteks Kuninglik Teater v i Rahvusteater – nimedes, mis olid kasutusel paljudes l neriikides. August Strindberg, kes avas oma Intiimteatri Stockholmis 1907. aastal, m ngis suurt rolli selle m iste ümberm testamisel. Tema jaoks ei olnud teater enam lihtsalt maja, vaid teatud tüüpi draama, mida esitati teatud tingimustel. Seega hakkas Strindberg propageerima sellist hoiakut teatri suhtes, mida manifesteeriti samal ajal üle kogu Euroopa. Teater eristus teistest etenduskunsti anritest nagu ooper, operett, tantsuteater, rahvalik kom dia, revüü, kabaree jne. Teatrit peeti eriliseks ning n uti nii n itekirjanikelt, n itlejatelt kui publikult erilist t sidust. Max Reinhardt kasutas m istet teater selleks, et esile tuua antirealistlikku l henemist teatrietendusele. Kuigi Strindbergi inspireeris Reinhardti Kammerteatri idee, siis Reinhardt ise laiendas teatri m istet re iikunsti kui selliseni: teater kui lavastaja kunst. See idee avaldas v ga suurt m ju teatriuurimisele, noorele distsipliinile. Teater kui k rgdraama ning samuti lavastamise k rge kunst j i domineerima kogu 20. sajandiks. Sajandi l pu poole aga hakkasid levima uued ideed: teater h bim rgistati kui vanamoodne euroopalik kontseptsioon – midagi v rreldavat keelpillikvartetiga –, samas kui pead t stis uus distsipliin – etendusuuringud. Etendus haarab siin enda alla k ikv imalikke tegevusi, alustades rituaalidest ja l petades paraadide v i jalgpalli ja ooperiga. Need erinevad teatri-m isted – selle materiaalsus v i kontseptuaalsus, v ljasulgevad v i ühendavad perspektiivid, uuenduslikkus v i vanamoodsus – on sügavalt m jutanud distsipliini(e), mis on loodud selle esteetilise ja sotsiaalse fenomeni uurimiseks. Antud artikkel demonstreerib, kuidas meie huvi teatriloo vastu varieerub vastavalt eelhoiakutele ja sellele, milliseid teadmisi me v rtustame, aga see omakorda s ltub sellest, kuidas me tajume teatrit: on see trükitud n idend, dramaatiline ettekanne, performatiivne ilmum, teatraliseeritud pilk – teater kui toode, kunstiteos v i sündmus.
Bloomsday: James Joyce's Ulysses Celebrated as Theatrical Event
Willmar Sauter
Culture Unbound : Journal of Current Cultural Research , 2009,
Abstract: James Joyce had decided that 16 June 1904 should be the one day in the life of Leopold Bloom, about which he wrote his 800 page novel Ulysses. In his book, Joyce actually followed Mr Bloom that entire day, from his getting up and having the nowadays famous kidney breakfast, to the late evening, when he had to break into his own house on 7 Eccle Street to have a drink with Stephen Dedalus, the other main figure of the novel. The centenary of that very day took, accordingly, place in 2004. I have borrowed the identity of Mr Bloom to describe some street scenes from the centennial celebrations of Bloomsday in Dublin. After this intro-ductory presentation, part two of this article will attempt to analyse Bloomsday in terms of a Theatrical Event, embedded in an unusual and striking playing culture. In a third part, Mr Bloom will once more be allowed to make some concluding comments.
The Emergence Project: A Machine of Expression
Daniel Sauter
Journal of the Chicago Colloquium on Digital Humanities and Computer Science , 2009,
Abstract: The Emergence Project is a software art installation exhibited at Hyde Park Art Center's digital facade gallery from October 11 until December 31, 2008. The piece investigates how complex patterns arise out of a series of simple interactions, without apparent direction or plan. Rising from the actual as-it's-happening discourse emanating out of the Chicago Humanities Festival, the presentations, performances, and panel discussions are captured, analyzed, and processed into visualizations that dynamically evolve from minute to minute. The generative artwork uses simple morphological rules to animate word clusters, based on linguistic proximity, similarity, and difference. In the work, hundreds of organic digital creatures embody contributions from panelists and the audience, captured by natural language processing software and the World Wide Web. The digital creatures, or idea clusters, continuously interact with each other, evaluating qualitative proximity in regards to their meaning and frequency. Thousands of local interactions between the creatures, as well as autonomous creation of new creatures, eventually generate patterns, that represent "big ideas" emerging from the discussions throughout the festival. The piece continues to evolve over time, reflecting the evolution process in form of graphical patterns, statistics and maps. Emergence has become one of the liveliest areas of research in philosophy and science. Examples of apparent emergent phenomena range from colonies of ants to the popularity of a particular hairstyle, and life itself. The Emergence Project interrogates the very concept of Emergence by reflexively adopting emergent behavior simulations to contemporary discourse on Emergence.
Generalized quiver Hecke algebras
Julia Sauter
Mathematics , 2013,
Abstract: We generalize the geometric construction of quiver Hecke algebras from Varagnolo and Vasserot to a setup with arbitrary connected reductive groups. This corresponds to replacing quiver representations by generalized quiver representations introduced by Derksen and Weyman. The class of algebras which we construct contains (affine) nil Hecke algebras, skew group rings of Weyl groups with polynomial rings and quiver Hecke algebras. We describe an explicit faithful representation in a polynomial ring and we calculate the generators and relations for these algebras.
Cell decompositions of quiver flag varieties for nilpotent representations of the oriented cycle
Julia Sauter
Mathematics , 2015,
Abstract: Generalizing Schubert cells in type $A$ and a cell decomposition if Springer fibres in type $A$ found by L. Fresse we prove that varieties of complete flags in nilpotent representations of an oriented cycle admit an affine cell decomposition parametrized by multi-tableaux. We show that they carry a torus operation and describe the $T$-equivariant cohomology using Goresky-Kottwitz-MacPherson-theory. As an application of the cell decomposition we obtain a vector space basis of standard modules (for quiver Hecke algebras of nilpotent representations of this quiver) introduced by Kato.
From complete to partial flags in geometric extension algebras
Julia Sauter
Mathematics , 2013,
Abstract: A geometric extension algebra is an extension algebra of a semi-simple perverse sheaf (allowing shifts), e.g. a push-forward of the constant sheaf under a projective map. Particular nice situations arise for collapsings of homogeneous vector bundle over homogeneous spaces. In this paper, we study the relationship between partial flag and complete flag cases. Our main result is that the locally finite modules over the geometric extension algebras are related by a recollement. As examples, we investigate parabolic affine nil Hecke algebras, geometric extension algebras associated to parabolic Springer maps and an example of Reineke of a parabolic quiver-graded Hecke algebra.
A Survey on Springer Theory
Julia Sauter
Mathematics , 2013,
Abstract: This is not standard in the sense that we understand a Springer map to be a collapsing of homogeneous bundles. Apart from that we use mostly techniques from Chriss and Ginzbergs book but we work in the equivariant derived category of Bernstein and Lunts. We define Steinberg algebras as (equivariant) Borel-Moore homology algebras of the associated Steinberg varieties. The data of the BBD-decomposition theorem applied to the Springer map give a parametrization of projective graded and simple graded modules over the Steinberg algebra. Also, the projective graded modules are equivalent to a category of shifts of perverse sheaves. This has as a consequence for example the Springer correspondence. We call classical Springer Theory what is usually considered as Springer Theory. The main results are parametrizations of simple modules of different types of Hecke algebras. Our second main example is quiver-graded Springer theory (due to Lusztig), here the Steinberg algebras are the quiver Hecke algebras. We also explain Lusztig's and Khovanov-Lauda's monoidal categorification of the negative half of the quantum group using the categories of shifts of perverse sheaves and projective graded modules over the quiver Hecke algebra respectively.
A New Adaptive Kalman Estimator for Detection and Isolation of Multiple Faults Integrated in a Fault Tolerant Control
H. Jamouli,D. Sauter
Journal of Control Science and Engineering , 2010, DOI: 10.1155/2010/497925
Abstract: For sequential jumps detection, isolation, and estimation in discrete-time stochastic linear systems, Willsky and Jones (1976) have developed the Generalized Likelihood Ratio (GLR) test. After each detection and isolation of one jump, the treatment of another possible jump is obtained by a direct state estimate and covariance incrementation of the Kalman filter originally designed on the jump-free system. This paper proposes to extend this approach from a state estimator designed on a reference model directly sensitive to system changes. We will show that the obtained passive GLR test can be easily integrated in a Fault Tolerant Control System (FTCS) via a control law designed in order to asymptotically reject the effect of sequential jumps. 1. Introduction First derived in a completely recursive form by Willsky and Jones [1], the GLR test has been used in a wide variety of applications including the detection of sensor and actuator failures [1–3], electrocardiogram analysis [4], geophysical signal processing [5], and freeways supervision [6]. For sequential jumps detection in discrete-time stochastic linear systems, the GLR test is made of the following steps: (1)detection and isolation of one possible jump by applying a GLR detector on the innovation sequence of the Kalman filter designed on the jump-free system,(2)updating of the Kalman filter using the jump magnitude estimate given by the GLR detector,(3)go to the step 1 to detect, isolate, and estimate another possible jump from measurements immediately available after the detection time of the last jump. The first part of this paper revisits the standard GLR test of Willsky and Jones [1] with respect to the fault detectability indexes [7] describing the time delay between the occurrence of a jump and its effect on measurements. The second part presents a new GLR test based on the augmented state Kalman estimator designed on the least favorable reference model including all the states of hypothetical jumps. This is not a new approach in the area of an FDI in dynamic systems-based observer. The well-known fault detection filter originally developed by Beard [8] is also designed from a fixed reference model including all the possible faults. The sequential multiple decision theory is not complete and this paper has not the pretention to give a unique solution of this general problem but only a usefull solution focussed on the integration of the obtained FDI scheme in an FTCS. Over the last two decades, growing demand for reliability, maintainability in dynamic systems has drawn significant research
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