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1
Wall, C. T. C. "Quartic curves in characteristic 2". Mathematical Proceedings of the Cambridge Philosophical Society 117, nr 3 (maj 1995): 393–414. http://dx.doi.org/10.1017/s0305004100073254.
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Simple singularities in positive characteristicSimple singularities in positive characteristic have been discussed by many authors, and the article [5] in particular establishes the subject on a firm footing. In it a simple, or ‘ADE’ singularity is defined by a list of normal forms and it is shown that the following conditions on a singularity are equivalent: (i) it is simple, (ii) it has finite deformation type, (iii) it has finite Cohen-Macaulay module type. Moreover, the normal forms for surface singularities coincide with the earlier list of Artin [1] and those for curves with the list of [9]: in those papers further characterizations were obtained.
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Chen, Yunxia, i Naichung Conan Leung. "ADE Bundles over Surfaces with ADE Singularities". International Mathematics Research Notices 2014, nr 15 (12.04.2013): 4049–84. http://dx.doi.org/10.1093/imrn/rnt065.
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Eguchi, Tohru, Nicholas P. Warner i Sung-Kil Yang. "ADE singularities and coset models". Nuclear Physics B 607, nr 1-2 (lipiec 2001): 3–37. http://dx.doi.org/10.1016/s0550-3213(01)00263-2.
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PERRONI, FABIO. "CHEN–RUAN COHOMOLOGY OF ADE SINGULARITIES". International Journal of Mathematics 18, nr 09 (październik 2007): 1009–59. http://dx.doi.org/10.1142/s0129167x07004436.
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We study Ruan's cohomological crepant resolution conjecture [41] for orbifolds with transversal ADE singularities. In the An-case, we compute both the Chen–Ruan cohomology ring [Formula: see text] and the quantum corrected cohomology ring H*(Z)(q1,…,qn). The former is achieved in general, the later up to some additional, technical assumptions. We construct an explicit isomorphism between [Formula: see text] and H*(Z)(-1) in the A1-case, verifying Ruan's conjecture. In the An-case, the family H*(Z)(q1,…,qn) is not defined for q1 = ⋯ = qn = -1. This implies that the conjecture should be slightly modified. We propose a new conjecture in the An-case (Conjecture 1.9). Finally, we prove Conjecture 1.9 in the A2-case by constructing an explicit isomorphism.
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Curto, Carina. "Matrix model superpotentials and ADE singularities". Advances in Theoretical and Mathematical Physics 12, nr 2 (2008): 353–404. http://dx.doi.org/10.4310/atmp.2008.v12.n2.a4.
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Kussin, Dirk, Helmut Lenzing i Hagen Meltzer. "Triangle singularities, ADE-chains, and weighted projective lines". Advances in Mathematics 237 (kwiecień 2013): 194–251. http://dx.doi.org/10.1016/j.aim.2013.01.006.
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Casalaina-Martin, Sebastian, i Radu Laza. "Simultaneous semi-stable reduction for curves with ADE singularities". Transactions of the American Mathematical Society 365, nr 5 (15.10.2012): 2271–95. http://dx.doi.org/10.1090/s0002-9947-2012-05579-6.
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Bakalov, Bojko, i Todor Milanov. "-constraints for the total descendant potential of a simple singularity". Compositio Mathematica 149, nr 5 (7.02.2013): 840–88. http://dx.doi.org/10.1112/s0010437x12000668.
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AbstractSimple, or Kleinian, singularities are classified by Dynkin diagrams of type $ADE$. Let $\mathfrak {g}$ be the corresponding finite-dimensional Lie algebra, and $W$ its Weyl group. The set of $\mathfrak {g}$-invariants in the basic representation of the affine Kac–Moody algebra $\hat {\mathfrak {g}}$ is known as a $\mathcal {W}$-algebra and is a subalgebra of the Heisenberg vertex algebra $\mathcal {F}$. Using period integrals, we construct an analytic continuation of the twisted representation of $\mathcal {F}$. Our construction yields a global object, which may be called a $W$-twisted representation of $\mathcal {F}$. Our main result is that the total descendant potential of the singularity, introduced by Givental, is a highest-weight vector for the $\mathcal {W}$-algebra.
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BÖHM, JANKO, WOLFRAM DECKER i MATHIAS SCHULZE. "LOCAL ANALYSIS OF GRAUERT–REMMERT-TYPE NORMALIZATION ALGORITHMS". International Journal of Algebra and Computation 24, nr 01 (luty 2014): 69–94. http://dx.doi.org/10.1142/s0218196714500064.
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Normalization is a fundamental ring-theoretic operation; geometrically it resolves singularities in codimension one. Existing algorithmic methods for computing the normalization rely on a common recipe: successively enlarge the given ring in form of an endomorphism ring of a certain (fractional) ideal until the process becomes stationary. While Vasconcelos' method uses the dual Jacobian ideal, Grauert–Remmert-type algorithms rely on so-called test ideals. For algebraic varieties, one can apply such normalization algorithms globally, locally, or formal analytically at all points of the variety. In this paper, we relate the number of iterations for global Grauert–Remmert-type normalization algorithms to that of its local descendants. We complement our results by a study of ADE singularities. All intermediate singularities occurring in the normalization process are determined explicitly. Besides ADE singularities the process yields simple space curve singularities from the list of Frühbis-Krüger.
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Fujita, Masato, i Masaru Kageyama. "On finiteness of prime cones over simple ADE-singularities of dimension one". Communications in Algebra 46, nr 9 (26.02.2018): 3986–95. http://dx.doi.org/10.1080/00927872.2018.1430808.
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ITO, KATSUSHI, i SUNG-KIL YANG. "ADE SINGULARITY AND PREPOTENTIALS IN N=2 SUPERSYMMETRIC YANG–MILLS THEORY". International Journal of Modern Physics A 13, nr 31 (20.12.1998): 5373–90. http://dx.doi.org/10.1142/s0217751x98002432.
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We calculate the instanton corrections in the effective prepotential for N=2 supersymmetric Yang–Mills theory with all ADE gauge groups from the Seiberg–Witten geometry constructed out of the spectral curves of the periodic Toda lattice. The one-instanton contribution is determined explicitly by solving the Gauss–Manin system associated with the ADE singularity. Our results are in complete agreement with the ones obtained from the microscopic instanton calculations.
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BELHAJ, A., i E. H. SAIDI. "ON HYPER-KAHLER SINGULARITIES". Modern Physics Letters A 15, nr 29 (21.09.2000): 1767–79. http://dx.doi.org/10.1142/s0217732300001638.
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Using a geometric realization of the SU (2)R symmetry and a procedure of factorization of the gauge and SU (2)R charges, we study the small instanton singularities of the Higgs branch of supersymmetric U (1)r gauge theories with eight supercharges. We derive new solutions for the moduli space of vacua preserving manifestly the eight supercharges. In particular, we obtain an extension of the ordinary ADE singularities for hyper-Kahler manifolds and show that the classical moduli space of vacua is in general given by cotangent bundles of compact weighted projective spaces.
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Rosa, Pilar de la, Alfonso Cobo i Maria De las Nieves González. "Vigas de pino silvestre sometidas a flexión: influencia de defectos y singularidades = Wild pine beams subjected to bending: influence of defects and singularities". Anales de Edificación 1, nr 3 (7.12.2015): 1. http://dx.doi.org/10.20868/ade.2015.3132.
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ResumenEn este trabajo se realiza un estudio experimental del comportamiento de dieciocho vigas de madera aserrada para uso estructural, de dimensiones 155x75x1090mm. La madera empleada ha sido de pino silvestre de Valsaín. Los ensayos se han realizado en el Laboratorio de Materiales de Construcción de la Escuela Técnica Superior de Edificación de Madrid. El objetivo del trabajo es el análisis del comportamiento a flexión de las piezas ensayadas teniendo en cuenta de los defectos y singularidades que presentan, realizando un estudio de la influencia de éstos. Se han ensayado dieciocho piezas en total, de las cuales nueve se colocaron en posición plana y las otras nueve de canto. Antes de proceder a los ensayos, la muestra ha sido clasificada según la norma UNE 56544 de clasificación visual de la madera aserrada para uso estructural, determinándose la calidad estructural de cada pieza y la clase resistente teniendo en cuenta que la especie de la madera es pino silvestre. Se identifican las singularidades y defectos que presenta cada una de las piezas y se mide la humedad, el peso y dimensiones de éstas. En las conclusiones se presentan los resultados del análisis realizado, comparando los datos de los ensayos con las características de las piezas, determinando la influencia de la presencia de defectos y las características de las piezas con sus propiedades mecánicas. AbstractThis paper presents an experimental study of the behavior of 18 timber beams for structural use of 155x75x1090mm dimensions. The origin of the wood is Valsaín sawmill. The tests were performed at the Laboratory of Construction Materials at the University School of Technical Architecture. The objective of this work is the analysis of flexural behavior of test pieces according to the defects and singularities, carrying out an analysis of their influence. 18 pieces have been tested, of which 9 were placed in a flat position, and the other 9 were placed in edge position. Before testing, the samples were classified according to UNE 56544 visual grading of sawn timber for structural use, determining the structural quality of each piece and the strength class. Singularities and defects found in each one of the pieces, moisture, weight and dimensions are measured and identified. The results of the analysis are presented in the conclusions, comparing the test data with the characteristics of the beams, determining the influence of the presence of defects and the characteristics of the timber beams with resistance in tests.Index Terms—
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Frutos, B., E. Muñoz, M. Olaya, C. Alonso i F. Martín Consuegra. "Singularidades en el diseño de soluciones de protección frente a gas radón = Singularities in the design of protection solutions against radon gas". Anales de Edificación 4, nr 2 (10.09.2018): 32. http://dx.doi.org/10.20868/ade.2018.3776.
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Resumen El isótopo del radón Rn-222, aparece en la naturaleza como producto de la desintegración natural del radio-226, común en la corteza terrestre. El potencial de exhalación de un terreno viene definido, por un lado, por el contenido de radio del sustrato (por ejemplo, los graníticos), y por otro, por la permeabilidad del mismo que permite la movilidad a través de los poros (fracturados). El radón, como elemento gaseoso, posee una alta movilidad y puede penetrar en los edificios a través de fisuras o grietas por advección o por difusión a través de la propia permeabilidad de los materiales de la envolvente que estén en contacto con el terreno. La acumulación de este gas en los recintos cerrados puede elevar las concentraciones y constituir un riesgo para la salud de las personas que lo inhalen. La OMS advierte de sus efectos, situándolo como agente cancerígeno de grado uno, siendo la segunda causa de contracción de cáncer de pulmón (la primera sería el tabaco). En esta comunicación se ofrecen pautas de diseño, y las particularidades asociadas a las estrategias de actuación, basándose en los estudios llevados a cabo a través de proyectos de investigación. Abstract The isotope of radon Rn-222, appears in nature as a product of the natural disintegration of radio-226, common in the earth's crust. The exhalation potential of a terrain is defined, on the one hand, by the radio content of the substrate (for example granitic), and on the other, by the permeability of the same that allows mobility through the pores (fractured). Radon, as a gaseous element, has a high mobility and can penetrate buildings through fissures or cracks by advection or diffusion through the permeability of the materials of the envelope that are in contact with the ground. The accumulation of this gas in enclosed areas can increase concentrations and constitute a risk to the health of people who inhale it. The WHO warns of its effects, placing it as a carcinogen of grade one, being the second cause of lung cancer contraction (the first would be tobacco). This communication offers design guidelines, and the particularities associated with the strategies of action, based on the studies carried out through research projects.
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LAAMARA, RACHID AHL, ADIL BELHAJ, LUIS J. BOYA i ANTONIO SEGUI. "ON LOCAL F-THEORY GEOMETRIES AND INTERSECTING D7-BRANES". International Journal of Geometric Methods in Modern Physics 06, nr 07 (listopad 2009): 1207–20. http://dx.doi.org/10.1142/s0219887809004181.
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We discuss local F-theory geometries and their gauge theory dualities in terms of intersecting D7-branes wrapped four-cycles in Type IIB superstring. The manifolds are built as elliptic K3 surface fibrations over intersecting F0 = CP1 × CP1 base geometry according to ADE Dynkin Diagrams. The base is obtained by blowing up the extended ADE hyper-Kähler singularities of eight-dimensional manifolds considered as sigma model target spaces with eight supercharges. The resulting gauge theory of such local F-theory models are given in terms of Type IIB D7-branes wrapped intersecting F0. The four-dimensional N = 1 anomaly cancelation requirement translates into a condition on the associated affine Lie algebras.
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Bellamy, Gwyn, i Alastair Craw. "Birational geometry of symplectic quotient singularities". Inventiones mathematicae 222, nr 2 (30.04.2020): 399–468. http://dx.doi.org/10.1007/s00222-020-00972-9.
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Abstract For a finite subgroup $$\Gamma \subset \mathrm {SL}(2,\mathbb {C})$$ Γ ⊂ SL ( 2 , C ) and for $$n\ge 1$$ n ≥ 1 , we use variation of GIT quotient for Nakajima quiver varieties to study the birational geometry of the Hilbert scheme of n points on the minimal resolution S of the Kleinian singularity $$\mathbb {C}^2/\Gamma $$ C 2 / Γ . It is well known that $$X:={{\,\mathrm{{\mathrm {Hilb}}}\,}}^{[n]}(S)$$ X : = Hilb [ n ] ( S ) is a projective, crepant resolution of the symplectic singularity $$\mathbb {C}^{2n}/\Gamma _n$$ C 2 n / Γ n , where $$\Gamma _n=\Gamma \wr \mathfrak {S}_n$$ Γ n = Γ ≀ S n is the wreath product. We prove that every projective, crepant resolution of $$\mathbb {C}^{2n}/\Gamma _n$$ C 2 n / Γ n can be realised as the fine moduli space of $$\theta $$ θ -stable $$\Pi $$ Π -modules for a fixed dimension vector, where $$\Pi $$ Π is the framed preprojective algebra of $$\Gamma $$ Γ and $$\theta $$ θ is a choice of generic stability condition. Our approach uses the linearisation map from GIT to relate wall crossing in the space of $$\theta $$ θ -stability conditions to birational transformations of X over $$\mathbb {C}^{2n}/\Gamma _n$$ C 2 n / Γ n . As a corollary, we describe completely the ample and movable cones of X over $$\mathbb {C}^{2n}/\Gamma _n$$ C 2 n / Γ n , and show that the Mori chamber decomposition of the movable cone is determined by an extended Catalan hyperplane arrangement of the ADE root system associated to $$\Gamma $$ Γ by the McKay correspondence. In the appendix, we show that morphisms of quiver varieties induced by variation of GIT quotient are semismall, generalising a result of Nakajima in the case where the quiver variety is smooth.
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GIROTTI, H. O., M. GOMES i A. J. DA SILVA. "INFRARED STRUCTURE OF (2 + 1)-DIMENSIONAL QUANTUM ELECTRODYNAMICS". Modern Physics Letters A 09, nr 29 (21.09.1994): 2699–704. http://dx.doi.org/10.1142/s0217732394002549.
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The Bloch–Nordsieck approximation is used to study the ir structure of quantum electrodynamics in 2 + 1 dimensions. Unlike in QED 4, the ir singularities occurring in each order of perturbation theory do not add up to a finite limit. However, the resummation of vacuum polarization graphs is shown to induce a mass which solves the ir problem.
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BESSA, MÁRIO. "The Lyapunov exponents of generic zero divergence three-dimensional vector fields". Ergodic Theory and Dynamical Systems 27, nr 5 (październik 2007): 1445–72. http://dx.doi.org/10.1017/s0143385707000107.
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AbstractWe prove that for a C1-generic (dense Gδ) subset of all the conservative vector fields on three-dimensional compact manifolds without singularities, we have for Lebesgue almost every (a.e.) point p∈M that either the Lyapunov exponents at p are zero or X is an Anosov vector field. Then we prove that for a C1-dense subset of all the conservative vector fields on three-dimensional compact manifolds, we have for Lebesgue a.e. p∈M that either the Lyapunov exponents at p are zero or p belongs to a compact invariant set with dominated splitting for the linear Poincaré flow.
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Chen, Bryan Gin-ge, Gareth P. Alexander i Randall D. Kamien. "Symmetry breaking in smectics and surface models of their singularities". Proceedings of the National Academy of Sciences 106, nr 37 (26.08.2009): 15577–82. http://dx.doi.org/10.1073/pnas.0905242106.
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The homotopy theory of topological defects in ordered media fails to completely characterize systems with broken translational symmetry. We argue that the problem can be understood in terms of the lack of rotational Goldstone modes in such systems and provide an alternate approach that correctly accounts for the interaction between translations and rotations. Dislocations are associated, as usual, with branch points in a phase field, whereas disclinations arise as critical points and singularities in the phase field. We introduce a three-dimensional model for two-dimensional smectics that clarifies the topology of disclinations and geometrically captures known results without the need to add compatibility conditions. Our work suggests natural generalizations of the two-dimensional smectic theory to higher dimensions and to crystals.
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Qing-Zhe, Zhang, Yan Bing, Dai Jing-Liang i Yang Bao-Gui. "Signal Analysis On Soil Stress From Vibrating Compaction Based On Wavelet Transform". Archives of Civil Engineering 60, nr 2 (1.06.2014): 257–68. http://dx.doi.org/10.2478/ace-2014-0017.
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Abstract The paper presented the wavelet transform method for d e-noising and singularity detection to soil compressive stress signal. The study results show that the reconstruction signals by the wavelet de-noising keeps the low frequency component at [0, 31.25Hz] of the original signal and improves the high frequency property at other frequency bands. The impaction time from the start time to resonance time of the stress signals is varies with the depth of the soil. With the increase of times of compaction, the impaction time of the stress is decreasing in every layer. But the speed of reaching compacted status in each layer is different.
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CASADIO, ROBERTO, i BENJAMIN HARMS. "CAN BLACK HOLES AND NAKED SINGULARITIES BE DETECTED IN ACCELERATORS?" International Journal of Modern Physics A 17, nr 31 (20.12.2002): 4635–45. http://dx.doi.org/10.1142/s0217751x02012259.
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We study the conditions for the existence of black holes that can be produced in colliders at the TeV-scale if the space–time is higher dimensional. On employing the microcanonical picture, we find that their life-times strongly depend on the details of the model. If the extra dimensions are compact (ADD model), microcanonical deviations from thermality are in general significant near the fundamental TeV mass, and tiny black holes decay more slowly than predicted by the canonical expression but still fast enough to disappear almost instantaneously. However, with one warped extra dimension (RS model), microcanonical corrections are much larger and tiny black holes appear to be (meta)stable. Further, if the total charge is not zero, we argue that naked singularities do not occur provided the electromagnetic field is strictly confined on an infinitely thin brane. However, they might be produced in colliders if the effective thickness of the brane is of the order of the fundamental length scale (~TeV-1).
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ANSELMI, DAMIANO, MARCO BILLÓ, PIETRO FRÉ, ALBERTO ZAFFARONI i LUCIANO GIRARDELLO. "ALE MANIFOLDS AND CONFORMAL FIELD THEORIES". International Journal of Modern Physics A 09, nr 17 (10.07.1994): 3007–57. http://dx.doi.org/10.1142/s0217751x94001199.
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We address the problem of constructing the family of (4,4) theories associated with the σ model on a parametrized family ℳζ of asymptotically locally Euclidean (ALE) manifolds. We rely on the ADE classification of these manifolds and on their construction as hyper-Kähler quotients, due to Kronheimer. By so doing we are able to define the family of (4,4) theories corresponding to a ℳζ family of ALE manifolds as the deformation of a solvable orbifold C2/Γ conformal field theory, Γ being a Kleinian group. We discuss the relation between the algebraic structure underlying the topological and metric properties of self-dual four-manifolds and the algebraic properties of nonrational (4,4) theories admitting an infinite spectrum of primary fields. In particular, we identify the Hirzebruch signature τ with the dimension of the local polynomial ring [Formula: see text] associated with the ADE singularity, with the number of nontrivial conjugacy classes in the corresponding Kleinian group and with the number of short representations of the (4,4) theory minus four.
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Kubicka, K., i U. Radoń. "Proposal for the Assessment of Steel Truss Reliability Under Fire Conditions". Archives of Civil Engineering 61, nr 4 (1.12.2015): 141–54. http://dx.doi.org/10.1515/ace-2015-0041.
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The paper presents a proposal for the assessment of the reliability of steel truss (both statically determinate and indeterminate) in the persistent and accidental design situation. In the analysis, a probabilistic approach was used. The global Hasofer-Lind reliability index was employed, computed in successive time steps for the whole structure, not for individual elements. The statically determinate truss was modelled as a serial system from the reliability standpoint. For the statically indeterminate truss, kinematically admissible failure mechanisms were determined by means of the examination of the singularity of the stiffness matrix of the structure, converting the truss into a geometrically variable system. For the problem thus formulated, a serial-parallel reliability model was constructed. Monitoring the reliability index in the successive minutes of the fire makes it possible to estimate the probability of the structure failure, and to decide whether the required safety level is maintained.
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Adde, Éloïse. "Le Nouveau conseil de Smil Flaška de Pardubice". Reinardus / Yearbook of the International Reynard Society 32 (31.12.2020): 1–19. http://dx.doi.org/10.1075/rein.00036.add.
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Abstrait Œuvre didactique qui tient tant du bestiaire, de la satire, du miroir au prince que de l’œuvre d’édification religieuse, le Nouveau conseil fait partie des grands textes de la littérature médiévale de langue tchèque. Rédigé en 1394–1395 par le seigneur Smil Flaška de Pardubice, actif partisan du mouvement de l’Union seigneuriale qui s’était opposé au roi, ce texte a souvent été analysé pour son contenu factuel (historique et politique) comme une critique du gouvernement de Venceslas IV. À travers une lecture anthropologique qui interroge l’utilisation du bestiaire, cet article propose de restituer l’épaisseur du message du Nouveau conseil, sa conception de l’homme et de sa place dans le monde (aspects sociaux) ainsi que dans la perspective de la providence. Plus qu’une satire, l’œuvre nous livre une représentation complexe de l’individu, à la charnière entre monde divin et monde terrestre, les animaux permettant de dire l’humanité dans sa diversité, l’individu dans sa singularité, et la personne dans sa complexité.
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Kunzinger, Michael, Argam Ohanyan, Benedict Schinnerl i Roland Steinbauer. "The Hawking–Penrose Singularity Theorem for $$C^1$$-Lorentzian Metrics". Communications in Mathematical Physics 391, nr 3 (26.02.2022): 1143–79. http://dx.doi.org/10.1007/s00220-022-04335-8.
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AbstractWe extend both the Hawking–Penrose theorem and its generalisation due to Galloway and Senovilla to Lorentzian metrics of regularity $$C^1$$ C 1 . For metrics of such low regularity, two main obstacles have to be addressed. On the one hand, the Ricci tensor now is distributional, and on the other hand, unique solvability of the geodesic equation is lost. To deal with the first issue in a consistent way, we develop a theory of tensor distributions of finite order, which also provides a framework for the recent proofs of the theorems of Hawking and of Penrose for $$C^1$$ C 1 -metrics (Graf in Commun Math Phys 378(2):1417–1450, 2020). For the second issue, we study geodesic branching and add a further alternative to causal geodesic incompleteness to the theorem, namely a condition of maximal causal non-branching. The genericity condition is re-cast in a distributional form that applies to the current reduced regularity while still being fully compatible with the smooth and $$C^{1,1}$$ C 1 , 1 -settings. In addition, we develop refinements of the comparison techniques used in the proof of the $$C^{1,1}$$ C 1 , 1 -version of the theorem (Graf in Commun Math Phys 360:1009–1042, 2018). The necessary results from low regularity causality theory are collected in an appendix.
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Rizal, Adhi, Riza Ibnu Adam i Susilawati Susilawati. "Sistem Kelas Virtual dan Pengelolaan Pembelajaran Berbasis 3-Dimensional Virtual World". Jurnal Edukasi dan Penelitian Informatika (JEPIN) 4, nr 2 (27.12.2018): 132. http://dx.doi.org/10.26418/jp.v4i2.27449.
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Penelitian ini bertujuan untuk mengembangkan dan menerapkan sistem kelas virtual berbasis dunia virtual 3 dimensi (3D). Kelas virtual dikembangkan berdasarkan framework pengembangan aplikasi ADDIE dengan meintegrasikan LMS Moodle, singularity viewer, SLOODLE, dan multi-user 3D application server OpenSimulator. Objek-objek yang ada pada kelas di dunia nyata direpresentasikan oleh objek 3D. Peserta didik dapat berinteraksi dengan objek-objek yang ada dalam kelas virtual untuk melaksanakan kegiatan pembelajaran. Pengujian kelas virtual dilakukan dengan cara menerapkannya untuk digunakan secara langsung oleh peserta didik dalam kegiatan pembelajaran. Pengujian dilakukan berdasarkan dua kriteria, yaitu evaluasi hasil belajar peserta didik dan uji penerimaan pengguna menggunakan Technology Acceptance Model (TAM). Hasil evaluasi hasil belajar menunjukan bahwa penggunaan kelas virtual tidak berpengaruh terhadap hasil belajar. Walaupun demikian, hasil uji penerimaan pengguna menunjukan bahwa kelas virtual dapat memberikan kepuasan dan dapat diterima untuk digunakan oleh peserta didik dalam proses pembelajaran.
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Vertogradov, Vitalii. "Forces in Schwarzschild, Vaidya and generalized Vaidya spacetimes". Journal of Physics: Conference Series 2081, nr 1 (1.11.2021): 012036. http://dx.doi.org/10.1088/1742-6596/2081/1/012036.
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Abstract In this paper we investigate how the leading term in the geodesic equation in Schwarzschild spacetime changes under the coordinate transformation to Eddington-Finkelstein coordinates. This term corresponds to the Newton force of attraction. Also we consider this term when we add the energy-momentum tensor of the form of the null dust and the null perfect fluid into right-hand side of the Einstein equation. We estimate the value of this force in Vaidya spacetime when the naked singularity formation occurs. Also we give conditions in generalized Vaidya spacetime when this force of attraction is replaced by the force of repulsion.
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GUENDELMAN, E. I. "NONSINGULAR ORIGIN OF THE UNIVERSE AND THE COSMOLOGICAL CONSTANT PROBLEM". International Journal of Modern Physics D 20, nr 14 (31.12.2011): 2767–71. http://dx.doi.org/10.1142/s0218271811020718.
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We consider a nonsingular origin for the universe starting from an Einstein static universe in the framework of a theory which uses two volume elements [Formula: see text] and Φd4x, where Φ is a metric independent density, also curvature, curvature square terms, first order formalism and for scale invariance a dilaton field ϕ are considered in the action. In the Einstein frame we also add a cosmological term that parametrizes the zero point fluctuations. The resulting effective potential for the dilaton contains two flat regions, for ϕ → ∞ relevant for the nonsingular origin of the universe and ϕ → -∞, describing our present universe. Surprisingly, avoidance of singularities and stability as ϕ → ∞ imply a positive but small vacuum energy as ϕ → -∞. Zero vacuum energy density for the present universe is the "threshold" for universe creation.
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Harahap, Evi Marlina. "GENEALOGI WACANA FOUCAULT TERHADAP KUMPULAN CERPEN “PROTES” KARYA PUTU WIJAYA". Jurnal Bahasa Indonesia Prima (BIP) 2, nr 1 (23.03.2020): 37–47. http://dx.doi.org/10.34012/bip.v2i1.870.
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Tulisan ini bertujuan untuk memberikan analisis karya sastra dari buku kumpulan cerpen “Protes” (1994) milik Putu Wijaya melalui perspektif wacana kuasa Michel Foucault. Metode yang digunakan adalah metode genealogi wacana Foucault. Analisis secara genealogis berusaha membangun dan mempertahankan singularitas peristiwa, meninggalkan peristiwa spektakuler untuk peristiwa sepele, serta melihat keseluruhan rentang fenomena yang sering ditolak sebagai sejarah. Cerpen yang dianalisis adalah “Sampah”, “Teror”, “Anjing (I)”, dan “Mimpi”. Berdasarkan empat cerpen yang dianalisis, semua mewacanakan permasalahan moral. Unsur yang didiamkan adalah institusi ataupun subjek yang menjalankan kekuasaan. Selain itu, dalam empat cerpen yang dianalisis, semuanya mengandung alat-alat yang mendukung strategi kekuasaan. Dengan demikian, ada kekuasaan di dalamnya. Kekuasaan itu dijadikan sebagai latar belakang cerpen untuk menyampaikan wacana Putu Wijaya mengenai moralitas.
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ADOUANI, ABDELHAMID, i HABIB MARZOUGUI. "Non-rigidity for circle homeomorphisms with several break points". Ergodic Theory and Dynamical Systems 39, nr 9 (28.11.2017): 2305–31. http://dx.doi.org/10.1017/etds.2017.121.
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In this work, we consider two class $P$-homeomorphisms, $f$ and $g$, of the circle with break point singularities, that are differentiable maps except at some singular points where the derivative has a jump. Assume that they have the same irrational rotation number of bounded type and that the derivatives $\text{Df}$ and $\text{Dg}$ are absolutely continuous on every continuity interval of $\text{Df}$ and $\text{Dg}$, respectively. We show that if $f$ and $g$ are not break-equivalent, then any topological conjugating $h$ between $f$ and $g$ is a singular function, i.e., it is continuous on the circle, but $\text{Dh}(x)=0$ almost everywhere (a.e.) with respect to the Lebesgue measure. In particular, this result holds under some combinatorial assumptions on the jumps at break points. It also generalizes previous results obtained for one and two break points and complements that of Cunha–Smania which was established for break equivalence.
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NICAISE, SERGE, i ANNA-MARGARETE SÄNDIG. "TRANSMISSION PROBLEMS FOR THE LAPLACE AND ELASTICITY OPERATORS: REGULARITY AND BOUNDARY INTEGRAL FORMULATION". Mathematical Models and Methods in Applied Sciences 09, nr 06 (sierpień 1999): 855–98. http://dx.doi.org/10.1142/s0218202599000403.
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This paper is devoted to some transmission problems for the Laplace and linear elasticity operators in two- and three-dimensional nonsmooth domains. We investigate the behaviour of harmonic and linear elastic fields near geometrical singularities, especially near corner points or edges where the interface intersects with the boundaries. We give a short overview about the known results for 2-D problems and add new results for 3-D problems. Numerical results for the calculation of the singular exponents in the asymptotic expansion are presented for both two- and three-dimensional problems. Some spectral properties of the corresponding parameter depending operator bundles are also given. Furthermore, we derive boundary integral equations for the solution of the transmission problems, which lead finally to "local" pseudo-differential operator equations with corresponding Steklov–Poincaré operators on the interface. We discuss their solvability and uniqueness. The above regularity results are used in order to characterize the regularity of the solutions of these integral equations.
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Moran, Joe. "Private Lives, Public Histories: The Diary in Twentieth-Century Britain". Journal of British Studies 54, nr 1 (styczeń 2015): 138–62. http://dx.doi.org/10.1017/jbr.2014.168.
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AbstractThis article examines the growth of interest in diary keeping in twentieth-century Britain. It explores how diary keeping by private citizens was encouraged in the first part of the century by mass-circulation newspapers, diary manufacturers, diary anthologists like Arthur Ponsonby, and the social research organization Mass Observation in response to changing notions of the self, privacy, and daily life. It discusses the ways in which, in the context of a growing interest in public archives, these private diaries have more recently been imagined as compelling forms of historical evidence, as well as some of the problems of organization and interpretation that these kinds of texts present. I argue that the inherently opaque and incomplete nature of private diaries means that they can add nuance to our understanding of the recent past and offer insight into the randomness and singularity of everyday experience as it is being lived.
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Tomasoni, Mattia, Sergio Gómez, Jake Crawford, Weijia Zhang, Sarvenaz Choobdar, Daniel Marbach i Sven Bergmann. "MONET: a toolbox integrating top-performing methods for network modularization". Bioinformatics 36, nr 12 (9.04.2020): 3920–21. http://dx.doi.org/10.1093/bioinformatics/btaa236.
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Abstract Summary We define a disease module as a partition of a molecular network whose components are jointly associated with one or several diseases or risk factors thereof. Identification of such modules, across different types of networks, has great potential for elucidating disease mechanisms and establishing new powerful biomarkers. To this end, we launched the ‘Disease Module Identification (DMI) DREAM Challenge’, a community effort to build and evaluate unsupervised molecular network modularization algorithms. Here, we present MONET, a toolbox providing easy and unified access to the three top-performing methods from the DMI DREAM Challenge for the bioinformatics community. Availability and implementation MONET is a command line tool for Linux, based on Docker and Singularity containers; the core algorithms were written in R, Python, Ada and C++. It is freely available for download at https://github.com/BergmannLab/MONET.git. Supplementary information Supplementary data are available at Bioinformatics online.
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Covre, André Monzoli, Flavia Alves da Silva, Gleison Oliosi, Caio Cezar Guedes Correa, Alexandre Pio Viana i Fabio Luiz Partelli. "Multi-Environment and Multi-Year Bayesian Analysis Approach in Coffee canephora". Plants 11, nr 23 (28.11.2022): 3274. http://dx.doi.org/10.3390/plants11233274.
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This work aimed to use the Bayesian approach to discriminate 43 genotypes of Coffea canephora cv. Conilon, which were cultivated in two producing regions to identify the most stable and productive genotypes. The experiment was a randomized block design with three replications and seven plants per plot, carried out in the south of Bahia and the north of Espírito Santo, environments with different climatic conditions, and evaluated during four harvests. The proposed Bayesian methodology was implemented in R language, using the MCMCglmm package. This approach made it possible to find great genetic divergence between the materials, and detect significant effects for both genotype, environment, and year, but the hyper-parametrized models (block effect) presented problems of singularity and convergence. It was also possible to detect a few differences between crops within the same environment. With a model with lower residual, it was possible to recommend the most productive genotypes for both environments: LB1, AD1, Peneirão, Z21, and P2.
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Smith, John. "The trinitarian dance with culture: Trinity as the missiological optic for understanding culture". Missiology: An International Review 48, nr 2 (8.01.2020): 154–68. http://dx.doi.org/10.1177/0091829619887386.
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In discussions of imago Dei, we largely confine ourselves to functional and moral affinity to God, that is that we have been made in God’s image with the result that obedience to God amounts to imitating his moral character and behavior. However, we need to add the existential affinity of God’s being to our understanding of God’s image in us, specifically the fact that he is both singular (in essence) and plural (in person). To some degree, people share God’s singular–plural quality and that one–many affinity can give great insight into gospel ministry. Moreover, as with the moral dimension of imago Dei, this singular–plural dimension also was marred by sin so that we, as individuals and as whole cultures, tend to lean toward one extreme or the other, toward singularity (unhealthy individualism) or plurality (monolithic communalism). The gospel of grace addresses both. Therefore, as we prepare to do ministry, we should study our audience to discern the existential lean of its own incarnation of imago Dei, so that we can best speak the gospel to fit audience need.
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Papadopoulos, C. A., i A. D. Dimarogonas. "Stability of Cracked Rotors in the Coupled Vibration Mode". Journal of Vibration and Acoustics 110, nr 3 (1.07.1988): 356–59. http://dx.doi.org/10.1115/1.3269525.
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A transverse surface crack is known to add to a shaft a local flexibility due to the stress-strain singularity in the vicinity of the crack tip. This flexibility can be represented, in the general case by way of a 6 × 6 compliance matrix describing the local flexibility in a short shaft element which includes the crack. This matrix has off-diagonal terms which cause coupling along the directions which are indicated by the off-diagonal terms. In addition, when the shaft rotates the crack opens and closes. Then the differential equations of motion have periodically varying stiffness coefficients and the solution can be expressed as a sum of harmonic functions of time. A method for the determination of the intervals of instability of the first and of second kind is developed. The results have been presented in stability charts in the frequency vs. depth of the crack domain. The coupling effect due to the crack leads to very interesting results such as new frequencies and vibration modes.
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Chaudhuri, Nirmalendu, i Mythily Ramaswamy. "Existence of positive solutions of some semilinear elliptic equations with singular coefficients". Proceedings of the Royal Society of Edinburgh: Section A Mathematics 131, nr 6 (grudzień 2001): 1275–95. http://dx.doi.org/10.1017/s0308210500001396.
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In this paper we consider the semilinear elliptic problem in a bounded domain Ω ⊆ Rn, where μ ≥ 0, 0 ≤ α ≤ 2, 2α* := 2(n − α)/(n − 2), f : Ω → R+ is measurable, f > 0 a.e, having a lower-order singularity than |x|-2 at the origin, and g : R → R is either linear or superlinear. For 1 < p < n, we characterize a class of singular functions Ip for which the embedding is compact. When p = 2, α = 2, f ∈ I2 and 0 ≤ μ < (½(n − 2))2, we prove that the linear problem has -discrete spectrum. By improving the Hardy inequality we show that for f belonging to a certain subclass of I2, the first eigenvalue goes to a positive number as μ approaches (½(n − 2))2. Furthermore, when g is superlinear, we show that for the same subclass of I2, the functional corresponding to the differential equation satisfies the Palais-Smale condition if α = 2 and a Brezis-Nirenberg type of phenomenon occurs for the case 0 ≤ α < 2.
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Zheng, Chuanxi, i Yuandong Gu. "Non-singular terminal extended sliding mode control of permanent magnet synchronous motor based on variable exponential reaching law". Journal of Physics: Conference Series 2365, nr 1 (1.11.2022): 012035. http://dx.doi.org/10.1088/1742-6596/2365/1/012035.
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Abstract A non-singular terminal extended sliding mode control method based on variable exponential reaching law is presented because the permanent magnet synchronous motor speed control system is subject to parameter disturbance, external disturbance, and end effect. In order to accomplish global rapid convergence and get rid of singularity, a non-singular terminal extended sliding mode surface is first created. After the system reaches the sliding mode surface, a new extended state variable is constructed in accordance with the first-order angular velocity model, and a new better exponential reaching law is utilized to eliminate chattering. Finally, a disturbance observer is designed to detect the disturbance during motor operation in real-time and add it to the speed control loop as a compensation. The simulation findings demonstrate that, in comparison to the conventional sliding mode control strategy, the suggested variable-parameter non-singular terminal sliding mode control strategy lowers the effect of disturbance on the motor’s real operation and has the benefits of rapid convergence speed, good resilience, minimal speed overshoot, and high control precision.
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Rizqi, Akhmad Wasiur. "KEPUASAN MAHASISWA FT UTM TERHADAP PELAYANAN AKADEMIK FT UTM MENGGUNAKAN MODEL EUROPEAN CUSTOMER SATISFACTION INDEX". MATRIK 20, nr 2 (31.03.2020): 1. http://dx.doi.org/10.30587/matrik.v20i2.946.
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Pada era globalisasi tantangan terhadap perguruan tinggi semakin meningkat. Pendidikan tinggi diharapkan dapat memberikan kontribusi melalui pengembangan Ilmu Pengetahuan dan Teknologi. Universitas Trunojoyo Madura (UTM) merupakan Perguruan Tinggi Negeri (PTN) pertama di pulau madura, Penelitian ini bertujuan untuk memodelkan kepuasan mahasiswa fakultas teknik UTM terhadap pelayanan akademik FT UTM kedalam bentuk model European Customer Satisfaction Index untuk mengetahui pengaruh variabel eksogen terhadap varabel endogen. Jumlah sampel sebanyak 321 responden yang terdiri dari 6 program studi yakni teknik industri, teknik informatika, teknik manajemen informatika, teknik mekatronika dan teknik multimedia jaringan. Analisis yang digunakan dalam penelitian ini adalah Structural Equation Modeling (SEM) dengan bantuan software amous 6.0. Berdasarkan hasil perhitungan uji kelayakan model, full model struktural SEM memenuhi syarat kelayakan model, yaitu dengan probabilitas sebesar 0,082. Pengujian goodness of fit lainnya menunjukkan dalam kategori yang diterima secara baik. critical ratio skewness value semua indikator berada di bawah 2,58. nilai p2 yang berada di bawah nilai 0,05 dan p1 diatas 0,5 sehingga tidak ada data yang outliyer. hasil determinan dari matriks kovarians sampelnya bernilai 1,6251≥0 menunjukkan bahwa tidak terdapat multikolinieritas atau singularitas pada data penelitian. Nilai reliabilitas variabel laten diatas 0,70. Uji hipotesis diketahui nilai CR diatas 1,96 dan nilai P dibawah 0,05. Ini menunjukkan variabel eksogen berpengaruh signifikan terhadap vaeibel endogen
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Shi, Hu, Zhixin Liang, Boyang Zhang i Haitao Wang. "Design and Performance Verification of a Novel RCM Mechanism for a Minimally Invasive Surgical Robot". Sensors 23, nr 4 (20.02.2023): 2361. http://dx.doi.org/10.3390/s23042361.
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Minimally invasive surgical robots have the advantages of high positioning accuracy, good stability, and flexible operation, which can effectively improve the quality of surgery and reduce the difficulty for doctors to operate. However, in order to realize the translation of the existing RCM mechanism, it is often necessary to add a mobile unit, which is often bulky and occupies most space above the patient’s body, thus causing interference to the operation. In this paper, a new type of planar RCM mechanism is proposed. Based on this mechanism, a 3-DOF robotic arm is designed, which can complete the required motion for surgery without adding a mobile unit. In this paper, the geometric model of the mechanism is first introduced, and the RCM point of the mechanism is proven during the motion process. Then, based on the establishment of the geometric model of the mechanism, a kinematics analysis of the mechanism is carried out. The singularity, the Jacobian matrix, and the kinematic performance of the mechanism are analyzed, and the working space of the mechanism is verified according to the kinematic equations. Finally, a prototype of the RCM mechanism was built, and its functionality was tested using a master–slave control strategy.
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Gliatto, Matthew T., i Isaac M. Held. "Overtransmission of Rossby Waves at a Lower-Layer Critical Latitude in the Two-Layer Model". Journal of the Atmospheric Sciences 77, nr 3 (17.02.2020): 859–70. http://dx.doi.org/10.1175/jas-d-19-0055.1.
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Abstract Rossby waves, propagating from the midlatitudes toward the tropics, are typically absorbed by critical latitudes (CLs) in the upper troposphere. However, these waves typically encounter CLs in the lower troposphere first. We study a two-layer linear scattering problem to examine the effects of lower CLs on these waves. We begin with a review of the simpler barotropic case to orient the reader. We then progress to the baroclinic case using a two-layer quasigeostrophic model in which there is vertical shear in the mean flow on which the waves propagate, and in which the incident wave is assumed to be an external-mode Rossby wave. We use linearized equations and add small damping to remove the critical-latitude singularities. We consider cases in which either there is only one CL, in the lower layer, or there are CLs in both layers, with the lower-layer CL encountered first. If there is only a CL in the lower layer, the wave’s response depends on the sign of the mean potential vorticity gradient at this lower-layer CL: if the PV gradient is positive, then the CL partially absorbs the wave, as in the barotropic case, while for a negative PV gradient, the CL is a wave emitter, and can potentially produce overreflection and/or overtransmission. Our numerical results indicate that overtransmission is by far the dominant response in these cases. When an upper-layer absorbing CL is encountered, following the lower-layer encounter, one can still see the signature of overtransmission at the lower-layer CL.
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Kravtchenko, J. "REMARKS ON THE CALCULATION OF AMPLITUDES OF THE LINEAR WAVE PRODUCED BY A WAVE MACHINE". Coastal Engineering Proceedings 1, nr 5 (29.01.2011): 5. http://dx.doi.org/10.9753/icce.v5.5.
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We are indebted to Havelock and to Biesel for their theoretical explanation of the mechanics of generation of the Stokes plane wave produced by a wave machine operating with a simple sinusoidal movement. The calculation of the wave amplitude, produced in this way, is the most salient feature of this theory.
We add nothing new to this research. But in view of its importance it seems fitting to pay special attention to a few mathematical difficulties that remain in the exposition of the above-mentioned authors, to indicate ways in which they may be solved in part, to simplify a few theoretical demonstrations and to make some comments on the physical significance of a theory which depends on very simplifying hypotheses.
More accurately speaking, we investigate a series of functions of one variable, introduced by Havelock and Biesel to present the solution of the problem. A gap in the theory is closed by showing that the series is complete; in fact, to establish this point, it is sufficient to employ a few results of the spectrum theory of certain differential operators. We complement then the indications of Biesel on the legitimacy of the term by term derivation of the series developments he has formed. Finally an elementary re-examination is made of the nature of singularities found in this solution and whose study has been made in a less direct manner in the works mentioned above. It would appear that all the above remarks can be of assistance to technicians in the study of many analogous questions.
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Moyano, Juan, Elena Cabrera-Revuelta, Juan E. Nieto-Julián, María Fernández-Alconchel i Pedro Fernández-Valderrama. "Evaluation of Geometric Data Registration of Small Objects from Non-Invasive Techniques: Applicability to the HBIM Field". Sensors 23, nr 3 (3.02.2023): 1730. http://dx.doi.org/10.3390/s23031730.
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Reverse engineering and the creation of digital twins are advantageous for documenting, cataloging, and maintenance control tracking in the cultural heritage field. Digital copies of the objects into Building Information Models (BIM) add cultural interest to every artistic work. Low-cost 3D sensors, particularly structured-light scanners, have evolved towards multiple uses in the entertainment market but also as data acquisition and processing techniques for research purposes. Nowadays, with the development of structured-light data capture technologies, the geometry of objects can be recorded in high-resolution 3D datasets at a very low cost. On this basis, this research addresses a small artifact with geometric singularities that is representative of small museum objects. For this, the precision of two structured-light scanners is compared with that of the photogrammetric technique based on short-range image capture: a high-cost Artec Spider 3D scanner, and the low-cost Revopoint POP 3D scanner. Data capture accuracy is evaluated through a mathematical algorithm and point set segmentation to verify the spatial resolution. In addition, the precision of the 3D model is studied through a vector analysis in a BIM environment, an unprecedented analysis until now. The work evaluates the accuracy of the devices through algorithms and the study of point density at the submillimeter scale. Although the results of the 3D geometry may vary in a morphometric analysis depending on the device records, the results demonstrate similar accuracies in that submillimeter range. Photogrammetry achieved an accuracy of 0.70 mm versus the Artec Spider and 0.57 mm against the Revopoint POP 3D scanner.
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Hurtado Anampa, Kenyi, Kevin Lannon, Douglas Thain i Ben Tovar. "Deploying and extending CMS Tier 3s using VC3 and the OSG Hosted CE service". EPJ Web of Conferences 214 (2019): 03035. http://dx.doi.org/10.1051/epjconf/201921403035.
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CMS Tier 3 centers, frequently located at universities, play an important role in the physics analysis of CMS data. Although different computing resources are often available at universities, meeting all requirements to deploy a valid Tier 3 able to run CMS workflows can be challenging in certain scenarios. For instance, providing the right operating system (OS)with access to the CERNVM File System (CVMFS) on the worker nodes or having a Compute Element (CE) on the submit host is not always allowed or possible due to e.g: lack of root access to the nodes, TCP port network policies, maintenance of a C,etc. The Notre Dame group operates a CMS Tier 3 with 1K cores. In addition to this, researchers have access to an opportunistic pool with +25K cores that are used via lobster for CMS jobs, but cannot be used with other standard CMS submission tools on the grid like CRAB, as these resources are not part of the Tier 3 due to its opportunistic nature. This work describes the use of VC3, a service for automating the deployment of virtual cluster infrastructures, in order to provide the environment (user-space CVMFS access and customized OS via singularity containers) needed for CMS workflows to work. Also, we describe its integration with the OSG Hosted CE service, to add these resources to CMS as part of our existing Tier 3 in a seamless way.
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Li, Cai, Wang, Zhang, Tang, Li, Liang i Yan. "Promising Generative Adversarial Network Based Sinogram Inpainting Method for Ultra-Limited-Angle Computed Tomography Imaging". Sensors 19, nr 18 (12.09.2019): 3941. http://dx.doi.org/10.3390/s19183941.
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Limited-angle computed tomography (CT) image reconstruction is a challenging problem in the field of CT imaging. In some special applications, limited by the geometric space and mechanical structure of the imaging system, projections can only be collected with a scanning range of less than 90°. We call this kind of serious limited-angle problem the ultra-limited-angle problem, which is difficult to effectively alleviate by traditional iterative reconstruction algorithms. With the development of deep learning, the generative adversarial network (GAN) performs well in image inpainting tasks and can add effective image information to restore missing parts of an image. In this study, given the characteristic of GAN to generate missing information, the sinogram-inpainting-GAN (SI-GAN) is proposed to restore missing sinogram data to suppress the singularity of the truncated sinogram for ultra-limited-angle reconstruction. We propose the U-Net generator and patch-design discriminator in SI-GAN to make the network suitable for standard medical CT images. Furthermore, we propose a joint projection domain and image domain loss function, in which the weighted image domain loss can be added by the back-projection operation. Then, by inputting a paired limited-angle/180° sinogram into the network for training, we can obtain the trained model, which has extracted the continuity feature of sinogram data. Finally, the classic CT reconstruction method is used to reconstruct the images after obtaining the estimated sinograms. The simulation studies and actual data experiments indicate that the proposed method performed well to reduce the serious artifacts caused by ultra-limited-angle scanning.
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Choi, Jin Haeng, Gimin Kim, Deok Won Lim i Chandeok Park. "Study on Optimal Broadcast Ephemeris Parameters for GEO/IGSO Navigation Satellites". Sensors 20, nr 22 (16.11.2020): 6544. http://dx.doi.org/10.3390/s20226544.
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This paper proposes new sets of suitable broadcast ephemeris parameters for geosynchronous (GEO) and inclined geosynchronous (IGSO) navigation satellites (NSs). Despite the increasing number of GEO and IGSO NSs, global positioning system (GPS)-type ephemeris parameters are still widely used for them. In an effort to provide higher fit accuracy, we analyze a variety of broadcast ephemeris parameters for GEO and IGSO satellites along with their orbital characteristics and propose optimal sets of parameters. Nonsingular elements and orbital plane rotation are adopted for alleviating/avoiding the singularity issues of GEO satellites. On the basis of 16 parameters of GPS LNAV, we add one to four parameters out of 28 correction ones to determine optimal sets of ephemeris parameters providing higher accuracy. All possible parameter sets are tested with the least-square curve fit for four BeiDou GEOs and six BeiDou IGSOs. Their fit accuracies are compared to determine the optimal broadcast ephemeris parameters that provide minimum fit errors. The set of optimal ephemeris parameters depends on the type of orbit. User range error (URE) accuracies of the proposed optimal ephemeris parameters ensure results within 2.4 cm for IGSO and 3.8 cm for GEO NSs. Moreover, the experimental results present common parameter sets for both IGSO and GEO for compatibility and uniformity. Compared with four conventional/well-known sets of ephemeris parameters for BeiDou, our proposed parameters can enhance accuracies of up to 34.5% in terms of URE. We also apply the proposed optimal parameter sets to one GEO and three IGSO satellites of QZSS. The effects of fitting intervals, number of parameters, total bits, and orbit types on the fit accuracy are addressed in detail.
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Hazlett, Randy D., i D. Krishna Babu. "Discrete Wellbore and Fracture Productivity Modeling for Unconventional Wells and Unconventional Reservoirs". SPE Journal 19, nr 01 (1.10.2013): 19–33. http://dx.doi.org/10.2118/159379-pa.
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Summary Newly developed, generalized analytic solutions to the heat equation for arbitrary 3D well trajectory in anisotropic media are demonstrated to solve benchmark horizontal- and slanted-well productivity problems with unprecedented speed and accuracy. Arbitrary well trajectory is constructed as an assemblage of spatially integrated, linear well segments, as opposed to a distribution of numerically integrated point sources, to provide advantages in both computational speed and accuracy in singularity handling. Production from each arbitrarily oriented segment is reduced to a combination of purely analytic expressions and rapidly convergent, exponentially damped infinite sum approximations. With offered flexibility in cell boundary conditions, the expressions can yield standalone well-productivity estimates for complex wells or serve as the basis for advanced well equations, if integrated within a numerical reservoir simulator. Transients are also computed with analytical integrations in time, thus requiring no time marching. The breakthrough speed and accuracy in productivity assessment open possibilities for advanced well-testing and reservoir-characterization methods. We further demonstrate the usefulness of analytic methodology with several time-dependent, discrete fracture problems for shale gas production with typical Barnett conditions, allowing direct use of complex fracture patterns, such as those interpreted from microseismic mapping. In addition to uniform-flux and uniform-pressure modeling options, a new analytic model is introduced that is capable of modeling both time-dependent material transport between matrix and a stimulated zone and the interplay between a well and fracture. We illustrate our solution method with Barnett fractured-well examples from the literature. With optional effects such as gas desorption and stress-dependent fracture conductivity as easy add-ons, we can produce full-operational-life production forecasts for shale or tight gas reservoirs from discrete, complex fracture patterns along with reservoir-pressure mappings in a matter of minutes on common PC platforms.
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Allain, Fabrice, Julien Roméjon, Philippe La Rosa, Frédéric Jarlier, Nicolas Servant i Philippe Hupé. "Geniac: Automatic Configuration GENerator and Installer for nextflow pipelines". Open Research Europe 1 (21.02.2022): 76. http://dx.doi.org/10.12688/openreseurope.13861.2.
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With the advent of high-throughput biotechnological platforms and their ever-growing capacity, life science has turned into a digitized, computational and data-intensive discipline. As a consequence, standard analysis with a bioinformatics pipeline in the context of routine production has become a challenge such that the data can be processed in real-time and delivered to the end-users as fast as possible. The usage of workflow management systems along with packaging systems and containerization technologies offer an opportunity to tackle this challenge. While very powerful, they can be used and combined in many multiple ways which may differ from one developer to another. Therefore, promoting the homogeneity of the workflow implementation requires guidelines and protocols which detail how the source code of the bioinformatics pipeline should be written and organized to ensure its usability, maintainability, interoperability, sustainability, portability, reproducibility, scalability and efficiency. Capitalizing on Nextflow, Conda, Docker, Singularity and the nf-core initiative, we propose a set of best practices along the development life cycle of the bioinformatics pipeline and deployment for production operations which target different expert communities including i) the bioinformaticians and statisticians ii) the software engineers and iii) the data managers and core facility engineers. We implemented Geniac (Automatic Configuration GENerator and Installer for nextflow pipelines) which consists of a toolbox with three components: i) a technical documentation available at https://geniac.readthedocs.io to detail coding guidelines for the bioinformatics pipeline with Nextflow, ii) a command line interface with a linter to check that the code respects the guidelines, and iii) an add-on to generate configuration files, build the containers and deploy the pipeline. The Geniac toolbox aims at the harmonization of development practices across developers and automation of the generation of configuration files and containers by parsing the source code of the Nextflow pipeline.
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Allain, Fabrice, Julien Roméjon, Philippe La Rosa, Frédéric Jarlier, Nicolas Servant i Philippe Hupé. "Geniac: Automatic Configuration GENerator and Installer for nextflow pipelines". Open Research Europe 1 (2.07.2021): 76. http://dx.doi.org/10.12688/openreseurope.13861.1.
Pełny tekst źródłaStreszczenie:
With the advent of high-throughput biotechnological platforms and their ever-growing capacity, life science has turned into a digitized, computational and data-intensive discipline. As a consequence, standard analysis with a bioinformatics pipeline in the context of routine production has become a challenge such that the data can be processed in real-time and delivered to the end-users as fast as possible. The usage of workflow management systems along with packaging systems and containerization technologies offer an opportunity to tackle this challenge. While very powerful, they can be used and combined in multiple ways thus increasing their usage complexity. Therefore, guidelines and protocols are required in order to detail how the source code of the bioinformatics pipeline should be written and organized to ensure its usability, maintainability, interoperability, sustainability, portability, reproducibility, scalability and efficiency. Capitalizing on Nextflow, Conda, Docker, Singularity and the nf-core initiative, we propose a set of best practices along the development life cycle of the bioinformatics pipeline and deployment for production operations which address different expert communities including i) the bioinformaticians and statisticians ii) the software engineers and iii) the data managers and core facility engineers. We implemented Geniac (Automatic Configuration GENerator and Installer for nextflow pipelines) which consists of a toolbox with three components: i) a technical documentation available at https://geniac.readthedocs.io to detail coding guidelines for the bioinformatics pipeline with Nextflow, ii) a linter to check that the code respects the guidelines, and iii) an add-on to generate configuration files, build the containers and deploy the pipeline. The Geniac toolbox aims at the harmonization of development practices across developers and automation of the generation of configuration files and containers by parsing the source code of the Nextflow pipeline. The Geniac toolbox and two demo pipelines are available on GitHub. This article presents the main functionalities of Geniac.
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Audain, Enrique, Yassel Ramos, Henning Hermjakob, Darren R. Flower i Yasset Perez-Riverol. "Accurate estimation of isoelectric point of protein and peptide based on amino acid sequences". Bioinformatics 32, nr 6 (14.11.2015): 821–27. http://dx.doi.org/10.1093/bioinformatics/btv674.
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Abstract Motivation: In any macromolecular polyprotic system—for example protein, DNA or RNA—the isoelectric point—commonly referred to as the pI—can be defined as the point of singularity in a titration curve, corresponding to the solution pH value at which the net overall surface charge—and thus the electrophoretic mobility—of the ampholyte sums to zero. Different modern analytical biochemistry and proteomics methods depend on the isoelectric point as a principal feature for protein and peptide characterization. Protein separation by isoelectric point is a critical part of 2-D gel electrophoresis, a key precursor of proteomics, where discrete spots can be digested in-gel, and proteins subsequently identified by analytical mass spectrometry. Peptide fractionation according to their pI is also widely used in current proteomics sample preparation procedures previous to the LC-MS/MS analysis. Therefore accurate theoretical prediction of pI would expedite such analysis. While such pI calculation is widely used, it remains largely untested, motivating our efforts to benchmark pI prediction methods. Results: Using data from the database PIP-DB and one publically available dataset as our reference gold standard, we have undertaken the benchmarking of pI calculation methods. We find that methods vary in their accuracy and are highly sensitive to the choice of basis set. The machine-learning algorithms, especially the SVM-based algorithm, showed a superior performance when studying peptide mixtures. In general, learning-based pI prediction methods (such as Cofactor, SVM and Branca) require a large training dataset and their resulting performance will strongly depend of the quality of that data. In contrast with Iterative methods, machine-learning algorithms have the advantage of being able to add new features to improve the accuracy of prediction. Contact: yperez@ebi.ac.uk Availability and Implementation: The software and data are freely available at https://github.com/ypriverol/pIR. Supplementary information: Supplementary data are available at Bioinformatics online.