709,237 research outputs found
Bethe Ansatz Solutions of the Bose-Hubbard Dimer
The Bose-Hubbard dimer Hamiltonian is a simple yet effective model for
describing tunneling phenomena of Bose-Einstein condensates. One of the
significant mathematical properties of the model is that it can be exactly
solved by Bethe ansatz methods. Here we review the known exact solutions,
highlighting the contributions of V.B. Kuznetsov to this field. Two of the
exact solutions arise in the context of the Quantum Inverse Scattering Method,
while the third solution uses a differential operator realisation of the su(2)
Lie algebra.Comment: This is a contribution to the Vadim Kuznetsov Memorial Issue on
Integrable Systems and Related Topics, published in SIGMA (Symmetry,
Integrability and Geometry: Methods and Applications) at
http://www.emis.de/journals/SIGMA
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General report of TC103 numerical methods in geomechanics
This paper presents a General Report on 46 contributions, including poster presentations, submitted for the parallel sessions organized by TC 103: Numerical Methods in Geomechanics. The authors come from various regions of the world and the topics of the submitted papers are diverse. These contributions are reviewed from the viewpoint of the current research directions in relation to the numerical schemes and their key results. The overview of the latest work is provided in this general report, dividing the broad paper topics into several important subjects
The integrated manual and automatic control of complex flight systems
Research dealt with the general area of optimal flight control synthesis for manned flight vehicles. The work was generic; no specific vehicle was the focus of study. However, the class of vehicles generally considered were those for which high authority, multivariable control systems might be considered, for the purpose of stabilization and the achievement of optimal handling characteristics. Within this scope, the topics of study included several optimal control synthesis techniques, control-theoretic modeling of the human operator in flight control tasks, and the development of possible handling qualities metrics and/or measures of merit. Basic contributions were made in all these topics, including human operator (pilot) models for multi-loop tasks, optimal output feedback flight control synthesis techniques; experimental validations of the methods developed, and fundamental modeling studies of the air-to-air tracking and flared landing tasks
Energy Levels Of Hydrogen-Like Atomsand Fundamental Constants
The present review includes the description of theoretical methods for the
investigations of the spectra of hydrogen-like systems. Various versions of the
quasipotential approach and the method of the effective Dirac equation are
considered. The new methods, which have been developed in the eighties, are
described. These are the method for the investigation of the spectra by means
of the quasipotential equation with the relativistic reduced mass and the
method for a selection of the logarithmic corrections by means of the
renormalization group equation. The special attention is given to the
construction of a perturbation theory and the selection of graphs, whereof the
contributions of different orders of , the fine structure constant, to
the energy of the fine and hyperfine splitting in a positronium, a muonium and
a hydrogen atom could be calculated.
In the second part of this article the comparison of the experimental results
and the theoretical results concerning the wide range of topics is produced.
They are the fine and hyperfine splitting in the hydrogenic systems, the Lamb
shift and the anomalous magnetic moments of an electron and a muon. Also, the
problem of the precision determination of a numerical value of the fine
structure constant, connected with the above topics, is discussed.Comment: LaTeX file, 68 pp. (figures are available on request
Advances on Mechanics, Design Engineering and Manufacturing III
This open access book gathers contributions presented at the International Joint Conference on Mechanics, Design Engineering and Advanced Manufacturing (JCM 2020), held as a web conference on June 2–4, 2020. It reports on cutting-edge topics in product design and manufacturing, such as industrial methods for integrated product and process design; innovative design; and computer-aided design. Further topics covered include virtual simulation and reverse engineering; additive manufacturing; product manufacturing; engineering methods in medicine and education; representation techniques; and nautical, aeronautics and aerospace design and modeling. The book is organized into four main parts, reflecting the focus and primary themes of the conference. The contributions presented here not only provide researchers, engineers and experts in a range of industrial engineering subfields with extensive information to support their daily work; they are also intended to stimulate new research directions, advanced applications of the methods discussed and future interdisciplinary collaborations
Arts-Based Methods in Education Around the World
Arts-Based Methods in Education Around the World aims to investigate arts-based encounters in educational settings in response to a global need for studies that connect the cultural, inter-cultural, cross-cultural, and global elements of arts-based methods in education. In this extraordinary collection, contributions are collected from experts all over the world and involve a multiplicity of arts genres and traditions. These contributions bring together diverse cultural and educational perspectives and include a large variety of artistic genres and research methodologies.The topics covered in the book range from policies to pedagogies, from social impact to philosophical conceptualisations. They are informative on specific topics, but also offer a clear monitoring of the ways in which the general attention to the arts in education evolves through time
Exploring Organizational Communication (Micro) History Through Network Connections
In light of the 100th anniversary of the National Communication Association, the following essay offers an initial look at the communication subdiscipline of organizational communication and its development over the past seven-plus decades. As part of this review, we advocate the use of network methods as a microhistory analytic tool to explore the vast number of connections, both between people and research interests, generated as the discipline developed from its humble beginnings. This work represents a small sample of the greater Organizational Communication Genealogy Project. This larger effort seeks to create a detailed review of the discipline as it explores the relationships between advisors and advisees, the development of dissertation and current research topics, the collaborative network of coauthorship, and the contributions of individual scholars through the analysis of interview data, narratives, and historical documents
A Topic Coverage Approach to Evaluation of Topic Models
Topic models are widely used unsupervised models of text capable of learning
topics - weighted lists of words and documents - from large collections of text
documents. When topic models are used for discovery of topics in text
collections, a question that arises naturally is how well the model-induced
topics correspond to topics of interest to the analyst. In this paper we
revisit and extend a so far neglected approach to topic model evaluation based
on measuring topic coverage - computationally matching model topics with a set
of reference topics that models are expected to uncover. The approach is well
suited for analyzing models' performance in topic discovery and for large-scale
analysis of both topic models and measures of model quality. We propose new
measures of coverage and evaluate, in a series of experiments, different types
of topic models on two distinct text domains for which interest for topic
discovery exists. The experiments include evaluation of model quality, analysis
of coverage of distinct topic categories, and the analysis of the relationship
between coverage and other methods of topic model evaluation. The contributions
of the paper include new measures of coverage, insights into both topic models
and other methods of model evaluation, and the datasets and code for
facilitating future research of both topic coverage and other approaches to
topic model evaluation.Comment: Results and contributions unchanged; Added new references; Improved
the contextualization and the description of the work (abstr, intro, 7.1
concl, rw, concl); Moved technical details of data and model building to
appendices; Improved layout
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