4,386 research outputs found
General solution for Hamiltonians with extended cubic and quartic potentials
We integrate with hyperelliptic functions a two-particle Hamiltonian with
quartic potential and additionnal linear and nonpolynomial terms in the
Liouville integrable cases 1:6:1 and 1:6:8.Comment: LaTex 2e. To appear, Theoretical and Mathematical Physics 200
Completeness of the cubic and quartic H\'enon-Heiles Hamiltonians
The quartic H\'enon-Heiles Hamiltonian passes the Painlev\'e test for
only four sets of values of the constants. Only one of these, identical to the
traveling wave reduction of the Manakov system, has been explicitly integrated
(Wojciechowski, 1985), while the three others are not yet integrated in the
generic case . We integrate them by building
a birational transformation to two fourth order first degree equations in the
classification (Cosgrove, 2000) of such polynomial equations which possess the
Painlev\'e property. This transformation involves the stationary reduction of
various partial differential equations (PDEs). The result is the same as for
the three cubic H\'enon-Heiles Hamiltonians, namely, in all four quartic cases,
a general solution which is meromorphic and hyperelliptic with genus two. As a
consequence, no additional autonomous term can be added to either the cubic or
the quartic Hamiltonians without destroying the Painlev\'e integrability
(completeness property).Comment: 10 pages, To appear, Theor.Math.Phys. Gallipoli, 34 June--3 July 200
Integration of a generalized H\'enon-Heiles Hamiltonian
The generalized H\'enon-Heiles Hamiltonian
with an additional
nonpolynomial term is known to be Liouville integrable for three
sets of values of . It has been previously integrated by genus
two theta functions only in one of these cases. Defining the separating
variables of the Hamilton-Jacobi equations, we succeed here, in the two other
cases, to integrate the equations of motion with hyperelliptic functions.Comment: LaTex 2e. To appear, Journal of Mathematical Physic
Float zone experiments in space
The molten zone/freezing crystal interface system and all the mechanisms were examined. If Marangoni convection produces oscillatory flows in the float zone of semiconductor materials, such as silicon, then it is unlikely that superior quality crystals can be grown in space using this process. The major goals were: (1) to determine the conditions for the onset of Marangoni flows in molten tin, a model system for low Prandtl number molten semiconductor materials; (2) to determine whether the flows can be suppressed by a thin oxide layer; and (3) based on experimental and mathematical analysis, to predict whether oscillatory flows will occur in the float zone silicon geometry in space, and if so, could it be suppressed by thin oxide or nitride films. Techniques were developed to analyze molten tin surfaces in a UHV system in a disk float zone geometry to minimize buoyancy flows. The critical Marangoni number for onset of oscillatory flows was determined to be greater than 4300 on atomically clean molten tin surfaces
On reductions of some KdV-type systems and their link to the quartic He'non-Heiles Hamiltonian
A few 2+1-dimensional equations belonging to the KP and modified KP
hierarchies are shown to be sufficient to provide a unified picture of all the
integrable cases of the cubic and quartic H\'enon-Heiles Hamiltonians.Comment: 12 pages, 3 figures, NATO ARW, 15-19 september 2002, Elb
From centralization to decentralization in Chinese higher education
Since the late 1970’s, the Chinese government has been gradually changing its traditional policy for providing higher education and has begun to emphasize the comprehensiveness of the universities. Interdisciplinary cooperation and the synergization of resources are being promoted, and institutional autonomy is gradually increasing. Schools and faculties have been restored in universities, and new research institutions, research schools, research centers and the like have been established. From a unitary three-level model— university/department/ teaching and research group—before the reform, the organizational structures of the universities have developed a new organizational structure that is more flexible and more open. This more adaptable structure is intended to meet the developmental demands of modern universities with close links being created between their work and regional economic and social development. China has moved from a very centralized educational system in which the main decisions were taken by the central government to a decentralized educational system. This reform is also taking place within the institutions of higher education, and their internal organizational structure has also become more decentralized
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Asymmetries in tongue-palate contact during speech
Research has shown that speech articulation tends to be asymmetrical in the transverse plane of the vocal tract. A recent meta-study of previously published electropalatograms revealed that 83% of these images show asymmetrical tongue-palate contact [1].
The present study investigated articulation asymmetry on the basis of a large number of electropalatograms acquired in a sentence-reading task at the Centre for Speech Technology Research, Edinburgh University (Mocha: Multichannel Articulatory Database). The vast majority (97.5%) of these palatograms showed some degree of left-right asymmetry, with greater contact on the left-hand side being the more common finding. Asymmetry was not strongly determined by voice or place of articulation. However, it was highly dependent on manner, with fricatives and the lateral approximant showing the greatest degree of asymmetry.
Characterisation of articulation asymmetry could improve our understanding of the speech-production process and its relationship with both neural organisation and the anatomy of the organs of speech
Person prominence and relation prominence : on the typology of syntactic relations with particular reference to Yucatec Maya
PM3969, ISO 639-3 : -, Maya language--Syntax1. Introduction 2. Theoretical background 2.1. The cognitive structure of a situation 2.1.1. Situation, situation core, and participants 2.1.2. Participant features 2.1.3. Participant roles 2.2. Syntactic functions 2.3. Correlation between syntactic functions and participant roles 3. Prominence in typology 3.1. Subject prominence vs. topic prominence 3.2. Reference domination vs. role domination 3.3. Person prominence vs. relation prominence 4. Languages investigated 4.1. Yucatec Maya 4.2. Samoan 4.3. Maori 4.4. Tamil 4.5. Lezgian 4.6. Korean 5. Prominence in syntactic constructions 5.1. Introduction 5.2. Higher predicates 5.2.1. Modal predicates 5.2.2. Phase predicates 5.2.3. Tense, aspect, and aktionsart auxiliaries 5.3. Possessive constructions 5.3.1. Part-whole relations 5.3.2. Ascription of possession 5.3.3. Predication of belonging 5.3.4. Ascription of property to body part 5.3.5. Affection of possessor 5.4. Mental, sensual, and emotional states and processes 5.4.1. Preliminaries 5.4.2. Sensual states and processes 5.4.3. Emotional states and processes 5.4.4. Mental states and processes 5.4.5. Conclusion 5.5. Benefactive 6. Relation prominence in YM: a historical-comparative perspective 6.1. Colonial Yucatec Maya 6.1.1. Preliminaries 6.1.2. Modal predicates 6.1.3. Phase predicates 6.1.4. Aspect auxiliaries 6.1.5. Conclusion 6.2. Cognate languages 6.2.1. Preliminaries 6.2.2. Higher predicates 6.2.3. Possessive constructions 6.2.4. Mental, sensual and emotional states and processes 6.2.5. Benefactive 6.2.6. Conclusion 7. Typology 7.1. Empirical generalizations 7.1.1. The domain of possession 136 7.1.2. Higher predicates 7.1.3. Participant roles 7.2. Grammatical correlations 7.3. Conclusion Indices Abbreviations Morpheme glosses & syntactic categories Languages Sources of data Bibliographical references LIST OF FIGURES LIST OF TABLE
Autonomy vs. control: Quality assurance and governmental policy in Flanders
Higher education in Flanders has seen some major changes in the 1990s. One of the key elements of the new higher education regulations was the quality assessment system. This exemplified best the government's policy of granting all institutions of higher education autonomy, making them responsible for their policies, while still keeping the quality of higher education somewhat under governmental control. In this article, we focus on the tension between the government's aim of improving and controlling the quality of higher education and universities ' concern for their autonomy. We describe the Flemish government's view on issues of quality in higher education and confront these with an account on the basis of case studies of how the quality assurance system was actually implemented in universities. We conclude that the model of the "market state" or the "evaluative state" is only realised partially in Flanders. The government is still interventionist when it comes to key policy issue
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Texture Segmentation: An Objective Comparison between Traditional and Deep-Learning Methodologies
This paper compares a series of traditional and deep learning methodologies for the segmentation of textures. Six well-known texture composites first published by Randen and Hus{\o}y were used to compare traditional segmentation techniques (co-occurrence, filtering, local binary patterns, watershed, multiresolution sub-band filtering) against a deep-learning approach based on the U-Net architecture. For the latter, the effects of depth of the network, number of epochs and different optimisation algorithms were investigated. Overall, the best results were provided by the deep-learning approach. However, the best results were distributed within the parameters, and many configurations provided results well below the traditional techniques
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