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981.
Falk Hüffner Nadja Betzler Rolf Niedermeier 《Journal of Combinatorial Optimization》2010,20(4):335-360
Polynomial-time data reduction is a classical approach to hard graph problems. Typically, particular small subgraphs are replaced
by smaller gadgets. We generalize this approach to handle any small subgraph that has a small separator connecting it to the
rest of the graph. The problem we study is the NP-hard Balanced Subgraph problem, which asks for a 2-coloring of a graph that minimizes the inconsistencies with given edge labels. It has applications
in social networks, systems biology, and integrated circuit design. The data reduction scheme unifies and generalizes a number
of previously known data reductions, and can be applied to a large number of graph problems where a coloring or a subset of
the vertices is sought. To solve the instances that remain after reduction, we use a fixed-parameter algorithm based on iterative
compression with a very effective heuristic speedup. Our implementation can solve biological real-world instances exactly
for which previously only approximations were known. In addition, we present experimental results for financial networks and
random networks. 相似文献
982.
Babacar Ndione 《Revue europeenne de demographie》2009,25(3):325-354
Despite the diversity of the variables considered, explanatory models of migration do not fully incorporate the locality of origin as a scale of observation for migratory behaviour. Migration is often perceived to generate notions of territory; conversely, are local territories drivers of mobility? If so, in what forms, and by what means? This article analyses international migration from the city of Kaolack in Senegal, with particular focus on the role of the neighbourhood in migration dynamics. Here, the neighbourhood is seen as relatively homogeneous and singular historical and social entity. The ties that are established and maintained from one generation to the next take the form of shared lifestyles and modes of organization which may influence inhabitants’ propensity to emigrate. 相似文献
983.
984.
Jun Guo 《Journal of Combinatorial Optimization》2010,19(4):492-500
Let
\mathbbF(2n+d)q2\mathbb{F}^{(2\nu+\delta)}_{q^{2}}
be a (2ν+δ)-dimensional unitary space of
\mathbbFq2\mathbb{F}_{q^{2}}
, where δ=0 or 1. In this paper we construct a family of inclusion matrices associated with subspaces of
\mathbbF(2n+d)q2\mathbb{F}^{(2\nu+\delta)}_{q^{2}}
, and exhibit its disjunct property. Moreover, we compare the ratio efficiency of this construction with others, and find
it smaller under some conditions. 相似文献
985.
986.
Using a unique sample on ageing first generation immigrants in France, we explore the distribution of grandchild care across
offspring and the impact of this transfer on the labour supply of the mother. Our results indicate that grandchild care is
spread unequally across siblings, and this inequality is driven more strongly by better labour market potential than by weaker
financial status of the recipient. There is further evidence that even after accounting for potential endogeneity and unobserved
heterogeneity, grandchild care has a positive impact on the labour supply of the mother. The pattern of intergenerational
time transfers differs across people with different national and religions backgrounds. 相似文献
987.
Robert W. Strack Karyn Kai Anderson Camelia M. Graham Naomi Tomoyasu 《Child and Adolescent Social Work Journal》2007,24(3):261-283
Analysis reported here examined youth in residential group home placements in order to better understand how sexual behaviors,
drug use, and environmental experiences differ by race and gender subgroups. Data were collected from 336 youth aged 14–21
residing in one of 41 group homes in Maryland. Chi square and logistic regression analyses were done to determine differences
on study variables among the race-gender groupings. Results demonstrate not only significant health concerns overall but notable
differences were also found between race-gender subgroups. Findings suggest that found race-gender subgroup differences might
be informative for tailoring programming for youth of residential group home settings. 相似文献
988.
Robert Perrucci Shelley MacDermid Ericka King Chiung-Ya Tang Ted Brimeyer Kamala Ramadoss Sally Jane Kiser Jennifer Swanberg 《Journal of Family and Economic Issues》2007,28(4):600-617
This paper provides a review and synthesis of research literature on the effects of shift work on workers’ physical health,
mental health/well-being, and family life. The focus is on current knowledge, unanswered questions, and new directions for
future research. The selection of research literature is guided by a general conceptual framework that identifies predictor
variables, moderating variables, and outcome variables. The paper concludes with a discussion of the variables that should
be incorporated into an agenda for future research. 相似文献
989.
990.