9,085 research outputs found
Asymptotic efficiency of two nonparametric competitors of Wilcoxon's two sample test
Asymptotic efficiency of two nonparametric competitors of Mann-Whitney-Wilcoxon U tes
Storing and Querying Probabilistic XML Using a Probabilistic Relational DBMS
This work explores the feasibility of storing and querying probabilistic XML in a probabilistic relational database. Our approach is to adapt known techniques for mapping XML to relational data such that the possible worlds are preserved. We show that this approach can work for any XML-to-relational technique by adapting a representative schema-based (inlining) as well as a representative schemaless technique (XPath Accelerator). We investigate the maturity of probabilistic rela- tional databases for this task with experiments with one of the state-of- the-art systems, called Trio
Torsional rigidity for cylinders with a Brownian fracture
We obtain bounds for the expected loss of torsional rigidity of a cylinder
of length due to a Brownian
fracture that starts at a random point in and runs until the first
time it exits . These bounds are expressed in terms of the geometry
of the cross-section . It is shown that if is a
disc with radius , then in the limit as the expected
loss of torsional rigidity equals for some . We derive
bounds for in terms of the expected Newtonian capacity of the trace of a
Brownian path that starts at the centre of a ball in with radius
and runs until the first time it exits this ball.Comment: 18 page
Heat content and inradius for regions with a Brownian boundary
In this paper we consider , Brownian motion of time length , in -dimensional Euclidean space and on the -dimensional
torus . We compute the expectation of (i) the heat content at time
of for fixed and in the
limit , when is kept at temperature 1 for all and has initial temperature 0, and (ii)
the inradius of for in the
limit .Comment: 13 page
Stretched Exponential Relaxation in the Biased Random Voter Model
We study the relaxation properties of the voter model with i.i.d. random
bias. We prove under mild condions that the disorder-averaged relaxation of
this biased random voter model is faster than a stretched exponential with
exponent , where depends on the transition rates
of the non-biased voter model. Under an additional assumption, we show that the
above upper bound is optimal. The main ingredient of our proof is a result of
Donsker and Varadhan (1979).Comment: 14 pages, AMS-LaTe
'Subject to control': shifting geographies of race and labour in US sugar agroindustry, 1930-1950
This article analyses how processes of racialization and place making converged in south Florida as the region's sugar agroindustry shifted from a southern US to a Caribbean labour market. The article engages theoretically at the intersection of the literatures on the geographies of race and labour, paying particular attention to ideas about the role of the state in each. I argue that such an engagement not only enhances the collective analytical power of such approaches, but that it is also critical for understanding agroindustry labour practices in south Florida. The empirical materials used include historical documents, reports and publications of the US Government and the United States Sugar Corporation (USSC). The analysis shows how ideas of corporate paternalism and industrial managerialism promoted by USSC were melded to an agricultural enterprise embedded in the racism of the Jim Crow South and the history of plantation slavery. The contradictions between USSC's dependence on cheap labour disciplined by Jim Crow violence and its corporate paternalism would never be fully reconciled and ultimately would prove untenable. As a consequence, sugar industry investors in collaboration with state labour regulators reimagined the ideal cane worker, elaborating intraracial categories of black labour based on place of origin. As the geography of labour markets was rescaled to the international level, the primary mechanism of labour control shifted from Jim Crow to summary deportation of foreign black workers from the Caribbean. This study contributes to our understanding of how historic processes of racialization are bound together with the political and economic processes of regional agroindustrial development
The renormalization transformation for two-type branching models
This paper studies countable systems of linearly and hierarchically
interacting diffusions taking values in the positive quadrant. These systems
arise in population dynamics for two types of individuals migrating between and
interacting within colonies. Their large-scale space-time behavior can be
studied by means of a renormalization program. This program, which has been
carried out successfully in a number of other cases (mostly one-dimensional),
is based on the construction and the analysis of a nonlinear renormalization
transformation, acting on the diffusion function for the components of the
system and connecting the evolution of successive block averages on successive
time scales. We identify a general class of diffusion functions on the positive
quadrant for which this renormalization transformation is well-defined and,
subject to a conjecture on its boundary behavior, can be iterated. Within
certain subclasses, we identify the fixed points for the transformation and
investigate their domains of attraction. These domains of attraction constitute
the universality classes of the system under space-time scaling.Comment: 48 pages, revised version, to appear in Ann. Inst. H. Poincare (B)
Probab. Statis
Interdisciplinary (retail) research: The business of geography and the geography of business
NoAt the 2005 British Academy of Management conference several well-known economic
geographers, including Neil Wrigley, Gordon Clark, and Susan Christopherson, called
for management researchers to engage with economic geographers on interrelated
geographical and managerial issues in the study of (retail) firms. In this commentary
we reflect upon the present geography -management interface.We begin by considering
the term `interdisciplinary research' and its relationship to any management - geography interface. This is followed by a context-specific discussion of international retailing and the role of research on the retail transnational corporation (TNC) in developing an interdisciplinary agenda. This commentary represents an initial more business and management focused response to the call from geography academics for more/better interdisciplinary research at the geography - management interface
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