10,105 research outputs found
A knowledge based system for linking information to support decision making in construction
This work describes the development of a project model centred on the information and knowledge generated and used by managers. It describes a knowledge-based system designed for this purpose. A knowledge acquisition exercise was undertaken to determine the tasks of project managers and the information necessary for and used by these tasks. This information was organised into a knowledge base for use by an expert system. The form of the knowledge lent itself to organisation into a link network. The structure of the knowledge-based system, which was developed, is outlined and its use described. Conclusions are drawn as to the applicability of the model and the final system. The work undertaken shows that it is feasible to benefit from the field of artificial intelligence to develop a project manager assistant computer program that utilises the benefit of information and its link
CryoTran user's manual, version 1.0
The development of cryogenic fluid management systems for space operation is a major portion of the efforts of the Cryogenic Fluids Technology Office (CFTO) at the NASA Lewis Research Center. Analytical models are a necessary part of experimental programs which are used to verify the results of experiments and are also used as a predictor for parametric studies. The CryoTran computer program is a bridge to obtain analytical results. The object of CryoTran is to coordinate these separate analyses into an integrated framework with a user-friendly interface and a common cryogenic property database. CryoTran is an integrated software system designed to help solve a diverse set of problems involving cryogenic fluid storage and transfer in both ground and low-g environments
Linear response strength functions with iterative Arnoldi diagonalization
We report on an implementation of a new method to calculate RPA strength
functions with iterative non-hermitian Arnoldi diagonalization method, which
does not explicitly calculate and store the RPA matrix. We discuss the
treatment of spurious modes, numerical stability, and how the method scales as
the used model space is enlarged. We perform the particle-hole RPA benchmark
calculations for double magic nucleus 132Sn and compare the resulting
electromagnetic strength functions against those obtained within the standard
RPA.Comment: 9 RevTeX pages, 11 figures, submitted to Physical Review
Improved numerical methods for infinite spin chains with long-range interactions
We present several improvements of the infinite matrix product state (iMPS)
algorithm for finding ground states of one-dimensional quantum systems with
long-range interactions. As a main new ingredient we introduce the superposed
multi-optimization (SMO) method, which allows an efficient optimization of
exponentially many MPS of different length at different sites all in one step.
Hereby the algorithm becomes protected against position dependent effects as
caused by spontaneously broken translational invariance. So far, these have
been a major obstacle to convergence for the iMPS algorithm if no prior
knowledge of the systems translational symmetry was accessible. Further, we
investigate some more general methods to speed up calculations and improve
convergence, which might be partially interesting in a much broader context,
too. As a more special problem, we also look into translational invariant
states close to an invariance braking phase transition and show how to avoid
convergence into wrong local minima for such systems. Finally, we apply the new
methods to polar bosons with long-range interactions. We calculate several
detailed Devil's Staircases with the corresponding phase diagrams and
investigate some supersolid properties.Comment: Main text: 17 pages plus references, 8 figures. Supplementary info: 6
pages. v2: improved presentation and more results adde
Optimisation of on-line principal component analysis
Different techniques, used to optimise on-line principal component analysis,
are investigated by methods of statistical mechanics. These include local and
global optimisation of node-dependent learning-rates which are shown to be very
efficient in speeding up the learning process. They are investigated further
for gaining insight into the learning rates' time-dependence, which is then
employed for devising simple practical methods to improve training performance.
Simulations demonstrate the benefit gained from using the new methods.Comment: 10 pages, 5 figure
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