284 research outputs found
Inter-regional migration modelling - a review and assessment
Population migration involves the relocation of individuals, households or moving groups between geographical locations. Aggregate spatial patterns of movement reflect complex combinations of motivation that influence migration behaviour and determine destination choice. Consequently there is a huge literature on modelling different types of migration at various spatial scales. This paper, which originates from a study for EUROSTAT to find a generally applicable migration model, endeavours to review the state of the art by exploiting the distinction between explanatory and projection models. Whilst the review inevitably lacks comprehensiveness, it demonstrates the difference between mathematical and statistical approaches, highlights a recent two-stage model developed for use in a policy context in the UK, and contrasts these methods with models developed in the context of multi-state demography and used for migration projection in the European Union.
Modular Miracles
Over the last 20 years, the modular function has become widely known through its miraculous intervention in two great mathematical achievements: the proof of Fermat\u27s last theorem and the moonshine of the monster simple group. In both cases, the modular function appears where no one expected it, and it bridges a chasm between seemingly unrelated fields. It is probably fair to say that, in these two cases, we do not yet fully understand how the modular magic works.
However, it can at least be said that these are not the first modular miracles. Ever since its discovery, in the early 19th century, the modular function has been an engine for spectacular and unexpected results. Now that things modular are back in the news, it is a good time to recall some of the modular miracles of the 19th century. They help us see the recent results in some perspective, and encourage us to believe that there is a lot more to be learned
Discharge transient coupling in large space power systems
Experiments have shown that plasma environments can induce discharges in solar arrays. These plasmas simulate the environments found in low earth orbits where current plans call for operation of very large power systems. The discharges could be large enough to couple into the power system and possibly disrupt operations. Here, the general concepts of the discharge mechanism and the techniques of coupling are discussed. Data from both ground and flight experiments are reviewed to obtain an expected basis for the interactions. These concepts were applied to the Space Station solar array and distribution system as an example of the large space power system. The effect of discharges was found to be a function of the discharge site. For most sites in the array discharges would not seriously impact performance. One location at the negative end of the array was identified as a position where discharges could couple to charge stored in system capacitors. This latter case could impact performance
Mr Kaiser You\u27ll Be Wiser
https://digitalcommons.library.umaine.edu/mmb-vp/5950/thumbnail.jp
In search of a modelling strategy for projecting internal migration in European countries - Demographic versus economic-geographical approaches
Internal migration is the most volatile and difficult to predict component of regional demographic change. A pure demographic approach using age and sex-specific parameters of migration intensities cannot fully capture the migration trends over time. One of the approaches that can be used for a better description of past trends and forecasting of future trends is to use additional non-demographic information such as regional economic indicators. In this paper we compare the predictive performance of pure demographic and extended economic-geographical models using data of four European countries at the so-called NUTS 2 level. The models are nested within a GLM specification%2C that allows both demographic and extended models to be written as specific cases of loglinear models. Therefore model fit and performance can be compared directly.
Методики исследования национальных брендов: отечественный и зарубежный опыт
Целью данной статьи является рассмотрение существующих
способов исследования и оценки национальных брендов для последующей разработки оптимального
метода исследования бренда «Украина»
Internal migration of britain's ethnic populations
Research findings report of INTERNAL MIGRATION OF BRITAIN'S ETHNIC POPULATIONS project. A project in the ESRC Understanding Population Trends and Processes Programme, maintained by the ReStore repository and archived to NCRM Eprints 2022
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