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Stanislav Keprta 《Statistics and Computing》1996,6(3):231-243
The main objective of this paper is to implement non-binary splits into Gelfand et al.'s modification of the CART algorithm. Multi-way splits can sometimes better reflect the structure of data than binary splits. Methods for the construction and comparison of such splits are described. 相似文献
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Much of the research on sexual attitudes has focused on biological sex as a predictor variable. This work has consistently demonstrated that men are more permissive in attitudes toward casual sex than are women. Less is known, however, about how other individual difference variables may shape sexual attitudes. In this research, we considered whether self-construal (whether one believes that others are or are not part of their self-concept) influences people’s attitudes toward casual sex. Specifically, we posited that an independent self-construal is positively related to, and an interdependent self-construal is negatively related to, sexual permissiveness. Two cross-sectional studies (ns = 517 and 212) yielded support for these hypotheses. We further considered autonomy as a potential process variable. A mediation analysis revealed that self-construal was related to autonomy, which in turn positively predicted sexual attitudes and drove this association. We integrate these findings into the literature on sexual attitudes and discuss theoretical insights derived from our findings. 相似文献
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Stanislav Molchanov 《Mathematical Population Studies》2017,24(3):147-160
A model of population dynamics in continuous time on the lattice contains the Kolmogorov-Petrovski-Piskunov equation as a special case. A limit distribution exists. The first three moments and the correlation function are expressed. 相似文献
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ABSTRACT This study analyzes the life histories and subcultural trajectories of people who have at one time but no longer identify as racist skinheads. We find that, on the one hand, people are far more malleable with their subcultural identities than is commonly understood by law enforcement and researchers concerned with criminal desistance, and on the other hand, this does not necessitate a total abdication of stable subcultural identities and values as some recent post-subculture scholars have asserted. Accordingly, we conceptualize the phenomena of subcultural trajectories and discuss the implications of these findings for future scholarship on subcultural participation and desistance as well as for potential public policies to successfully fight racism. 相似文献
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Flocking is oftentimes used to metaphorically describe social behavior. Do people actually flock in a way that avian species do? This paper develops a purely ecological mechanism for explaining similarity in human behavior by distinguishing between social networks of person-to-person ties and ecological networks of ties of observability. I test the “information center hypothesis” [Ibis 115 (1973) 517] from bioecology on the career mobility of professional managers who all graduated from the same university. In this case, spatial proximity in birds is replaced with sociodemographic homophily on an acquired status characteristic among persons. The results indicate that homophilous individuals exchange information about a favorable destination state by ecological ties of observability, that is, they follow the career mobility of fellow alumni and “flock” along with them. 相似文献
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A Heuristic for the Maximum Independent Set Problem Based on Optimization of a Quadratic Over a Sphere 总被引:1,自引:1,他引:1
Stanislav Busygin Sergiy Butenko Panos M. Pardalos 《Journal of Combinatorial Optimization》2002,6(3):287-297
For a given graph the maximum independent set problem is to find a maximum subset of vertices no two of which are adjacent. We propose a heuristic for the maximum independent set problem which utilizes classical results for the problem of optimization of a quadratic function over a sphere. The efficiency of the approach is confirmed by results of numerical experiments on DIMACS benchmarks. 相似文献
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