3,138,370 research outputs found
Dundee Discussion Papers in Economics 253:Spatial Interactions in Hedonic Pricing Models: The Urban Housing Market of Aveiro, Portugal
Spatial heterogeneity, spatial dependence and spatial scale constitute key features of spatial analysis of housing markets. However, the common practice of modelling spatial dependence as being generated by spatial interactions through a known spatial weights matrix is often not satisfactory. While existing estimators of spatial weights matrices are based on repeat sales or panel data, this paper takes this approach to a cross-section setting. Specifically, based on an a priori definition of housing submarkets and the assumption of a multifactor model, we develop maximum likelihood methodology to estimate hedonic models that facilitate understanding of both spatial heterogeneity and spatial interactions. The methodology, based on statistical orthogonal factor analysis, is applied to the urban housing market of Aveiro, Portugal at two different spatial scales
Spatial Analysis Of Human Capital Structures
An in-depth analysis of the occupational structure of the labour market in a spatial cross-section is an important theoretical and practical area of study necessary for the development of effective labour market policies and the education system
Regularized Principal Component Analysis for Spatial Data
In many atmospheric and earth sciences, it is of interest to identify
dominant spatial patterns of variation based on data observed at locations
and time points with the possibility that . While principal component
analysis (PCA) is commonly applied to find the dominant patterns, the
eigenimages produced from PCA may exhibit patterns that are too noisy to be
physically meaningful when is large relative to . To obtain more precise
estimates of eigenimages, we propose a regularization approach incorporating
smoothness and sparseness of eigenimages, while accounting for their
orthogonality. Our method allows data taken at irregularly spaced or sparse
locations. In addition, the resulting optimization problem can be solved using
the alternating direction method of multipliers, which is easy to implement,
and applicable to a large spatial dataset. Furthermore, the estimated
eigenfunctions provide a natural basis for representing the underlying spatial
process in a spatial random-effects model, from which spatial covariance
function estimation and spatial prediction can be efficiently performed using a
regularized fixed-rank kriging method. Finally, the effectiveness of the
proposed method is demonstrated by several numerical example
Perturbative analysis of generally nonlocal spatial optical solitons
In analogy to a perturbed harmonic oscillator, we calculate the fundamental
and some other higher order soliton solutions of the nonlocal nonlinear
Schroedinger equation (NNLSE) in the second approximation in the generally
nonlocal case. Comparing with numerical simulations we show that soliton
solutions in the 2nd approximation can describe the generally nonlocal soliton
states of the NNLSE more exactly than that in the zeroth approximation. We show
that for the nonlocal case of an exponential-decay type nonlocal response the
Gaussian-function-like soliton solutions can't describe the nonlocal soliton
states exactly even in the strongly nonlocal case. The properties of such
nonlocal solitons are investigated. In the strongly nonlocal limit, the
soliton's power and phase constant are both in inverse proportion to the 4th
power of its beam width for the nonlocal case of a Gaussian function type
nonlocal response, and are both in inverse proportion to the 3th power of its
beam width for the nonlocal case of an exponential-decay type nonlocal
response.Comment: 13 pages, 16 figures, accepted by Phys. Rev.
UK open source crime data: accuracy and possibilities for research
In the United Kingdom, since 2011 data regarding individual police recorded crimes have been made openly available to the public via the police.uk website. To protect the location privacy of victims these data are obfuscated using geomasking techniques to reduce their spatial accuracy. This paper examines the spatial accuracy of the police.uk data to determine at what level(s) of spatial resolution – if any – it is suitable for analysis in the context of theory testing and falsification, evaluation research, or crime analysis. Police.uk data are compared to police recorded data for one large metropolitan Police Force and spatial accuracy is quantified for four different levels of geography across five crime types. Hypotheses regarding systematic errors are tested using appropriate statistical approaches, including methods of maximum likelihood. Finally, a “best-fit” statistical model is presented to explain the error as well as to develop a model that can correct it. The implications of the findings for researchers using the police.uk data for spatial analysis are discussed
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