18,732 research outputs found
A comparison of two techniques for bibliometric mapping: Multidimensional scaling and VOS
VOS is a new mapping technique that can serve as an alternative to the
well-known technique of multidimensional scaling. We present an extensive
comparison between the use of multidimensional scaling and the use of VOS for
constructing bibliometric maps. In our theoretical analysis, we show the
mathematical relation between the two techniques. In our experimental analysis,
we use the techniques for constructing maps of authors, journals, and keywords.
Two commonly used approaches to bibliometric mapping, both based on
multidimensional scaling, turn out to produce maps that suffer from artifacts.
Maps constructed using VOS turn out not to have this problem. We conclude that
in general maps constructed using VOS provide a more satisfactory
representation of a data set than maps constructed using well-known
multidimensional scaling approaches
Image Reconstruction from Bag-of-Visual-Words
The objective of this work is to reconstruct an original image from
Bag-of-Visual-Words (BoVW). Image reconstruction from features can be a means
of identifying the characteristics of features. Additionally, it enables us to
generate novel images via features. Although BoVW is the de facto standard
feature for image recognition and retrieval, successful image reconstruction
from BoVW has not been reported yet. What complicates this task is that BoVW
lacks the spatial information for including visual words. As described in this
paper, to estimate an original arrangement, we propose an evaluation function
that incorporates the naturalness of local adjacency and the global position,
with a method to obtain related parameters using an external image database. To
evaluate the performance of our method, we reconstruct images of objects of 101
kinds. Additionally, we apply our method to analyze object classifiers and to
generate novel images via BoVW
Toward improved identifiability of hydrologic model parameters: The information content of experimental data
We have developed a sequential optimization methodology, entitled the parameter identification method based on the localization of information (PIMLI) that increases information retrieval from the data by inferring the location and type of measurements that are most informative for the model parameters. The PIMLI approach merges the strengths of the generalized sensitivity analysis (GSA) method [Spear and Hornberger, 1980], the Bayesian recursive estimation (BARE) algorithm [Thiemann et al., 2001], and the Metropolis algorithm [Metropolis et al., 1953]. Three case studies with increasing complexity are used to illustrate the usefulness and applicability of the PIMLI methodology. The first two case studies consider the identification of soil hydraulic parameters using soil water retention data and a transient multistep outflow experiment (MSO), whereas the third study involves the calibration of a conceptual rainfall-runoff model
- …