168 research outputs found
Education, Job Requirements, and Commuting: An Analysis of Network Flows
By now measures of employment "access" and "potential" have been widely diffused in the literature on regional economics and transport planning. Pooler (1995) gives a brief review of accessibility measures, indicating that these concepts date back to the 1930s. According to standard economic intuition, the employment access of a residential area increases with its proximity to concentrations of employment opportunities. The various indices of accessibility which have been proposed merely formalize and quantify this notion
Analogs, theories, and decision making
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45973/1/10110_2005_Article_BF01954598.pd
Spatial theory and human behavior
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45971/1/10110_2005_Article_BF01952731.pd
Defect model for the mixed mobile ion effect
This paper presents a new defect model for the mixed mobile ion effect. The
essential physical concept involved is that simultaneous migration of two
unlike mobile ions in mixed ionic glass is accompanied by expansion or
contraction of the guest-occupied sites with distortion of surrounding glass
matrix; in many cases, an intensity of the local stresses in glass matrix
surrounding ionic sites occupied by foreign ions is much greater than, or at
least comparable to the glass network binding energy. Hence, when the stress
exceeds the breaking threshold, relaxation occurs almost immediately via the
rupture of the bonds in the nearest glass matrix with generation of pairs of
intrinsic structural defects. The specificity of the mechanism of defect
generation leads to the clustering of negatively charged defects, so that
rearranged sites act as high energy anion traps in glass matrix. This results
in the immobilization of almost all minority mobile species and part of
majority mobile species, so mixed mobile ion glass behaves as single mobile ion
glass of much lower concentration of charge carriers. Generation of defects
leads also to the depolymerization of glass network, which in turn results in
the reduction of the glass viscosity and Tg as well as in the compaction of
glass structure (thermometer effect). The magnitude of the mixed mobile ion
effect is defined by the size mismatch of unlike mobile ions, their total and
relative concentrations, the binding energy of the glass-forming network, and
temperature. Although the proposed model is based upon the exploration of
alkali silicate glass-forming system, the approach developed here can be easily
adopted to other mixed ionic systems such as crystalline and even liquid ionic
conductors.Comment: 33 pages, 2 figure
Permit Allocation in Emissions Trading using the Boltzmann Distribution
In emissions trading, the initial allocation of permits is an intractable
issue because it needs to be essentially fair to the participating countries.
There are many ways to distribute a given total amount of emissions permits
among countries, but the existing distribution methods, such as auctioning and
grandfathering, have been debated. In this paper we describe a new method for
allocating permits in emissions trading using the Boltzmann distribution. We
introduce the Boltzmann distribution to permit allocation by combining it with
concepts in emissions trading. We then demonstrate through empirical data
analysis how emissions permits can be allocated in practice among participating
countries. The new allocation method using the Boltzmann distribution describes
the most probable, natural, and unbiased distribution of emissions permits
among multiple countries. Simple and versatile, this new method holds potential
for many economic and environmental applications.Comment: 25 pages of main text, 3 figures, 3 table
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