Although theoretical results for several algorithms in many application domains were presented during the last decades, not
all algorithms can be analyzed fully theoretically. Experimentation is necessary. The analysis of algorithms should follow
the same principles and standards of other empirical sciences. This article focuses on stochastic search algorithms, such
as evolutionary algorithms or particle swarm optimization. Stochastic search algorithms tackle hard real-world optimization
problems, e.g., problems from chemical engineering, airfoil optimization, or bio-informatics, where classical methods from
mathematical optimization fail. Nowadays statistical tools that are able to cope with problems like small sample sizes, non-normal
distributions, noisy results, etc. are developed for the analysis of algorithms. Although there are adequate tools to discuss
the statistical significance of experimental data, statistical significance is not scientifically meaningful per se. It is
necessary to bridge the gap between the statistical significance of an experimental result and its scientific meaning. We
will propose some ideas on how to accomplish this task based on Mayo’s learning model (NPT*). 相似文献
New Caledonian crows are the most proficient non-hominin tool manufacturers but the cognition behind their remarkable skills
remains largely unknown. Here we investigate if they attend to the functional properties of the tools that they routinely
use in the wild. Pandanus tools have natural barbs along one edge that enable them to function as hooking implements when
the barbs face backwards from the working tip. In experiment 1 we presented eight crows with either a non-functional (‘upside-down’)
or a functional pandanus tool in a baited hole. Four of the crows never flipped the tools. The behaviour of the four flipping
birds suggested that they had a strategy of flipping a tool when it was not working. Observations of two of the eight crows
picking up pandanus tools at feeding tables in the wild supported the lack of attention to barb direction. In experiment 2
we gave six of the eight crows a choice of either a barbed or a barbless pandanus tool. Five of the crows chose tools at random,
which further supported the findings in experiment 1 that the crows paid little or no attention to the barbs. In contrast,
a third experiment found that seven out of eight crows flipped non-functional stick tools significantly more than functional
ones. Our findings indicate that the crows do not consistently attend to the presence or orientation of barbs on pandanus
tools. Successful pandanus tool use in the wild seems to rely on behavioural strategies formed through associative learning,
including procedural knowledge about the sequence of operations required to make a successful pandanus tool.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
Recent attempts to medicalize women’s sexual “dysfunction” are critiqued and a “New View” of women’s sexual problems is introduced. The author argues for a female-centered perspective on women’s sexual desires and problems, based on a review of the literature on women’s sexuality and her observations of young women’s sexual experiences from 25 years of teaching Human Sexuality to undergraduate women. The review suggests that a pill or a patch cannot adequately address the sexual problems commonly experienced by US women. 相似文献
This paper presents Automath encodings (which are also valid in LF/λP) of various kinds of foundations of mathematics. Then it compares these encodings according to their size, to find out which foundation is the simplest.
The systems analyzed in this way are two kinds of set theory (ZFC and NF), two systems based on Church's higher order logic (Isabelle/Pure and HOL), three kinds of type theory (the calculus of constructions, Luo's extended calculus of constructions, and Martin-Löf's predicative type theory) and one foundation based on category theory.
The conclusions of this paper are that the simplest system is type theory (the calculus of constructions), but that type theories that know about serious mathematics are not simple at all. In that case the set theories are the simplest. If one looks at the number of concepts needed to explain such a system, then higher order logic is the simplest, with twenty-five concepts. On the other side of the scale, category theory is relatively complex, as is Martin-Löf's type theory.
(The full Automath sources of the contexts described in this paper are one the web at http://www.cs.ru.nl/~freek/zfc-etc/.) 相似文献
Using the socialization and attraction-selection-attrition (ASA) frameworks, this study examined the relation between employees’ work values and their organization’s values (person-organization fit). With a two year time interval, 140 respondents participated in a longitudinal study. After entry, socialization served to enhance homogeneity. The work values underwent small changes and the perception of fit with the organization grew. Despite high retention rates results confirmed the attrition effect. Results indicated that the lower the perceived match between own and organizational values at entry, the more likely it was that someone left the organization over time. We concluded that socialization as well as attrition mechanisms were present at the same time. 相似文献
Using the example of the Catholic Church in Papua New Guinea (PNG), I detail how, through praxis, it has brought to life a
living theology of HIV and AIDS. In this way, the Catholic Church in PNG is responding faithfully to the epidemic. As a Christian
country with a generalised HIV epidemic, where the body of an individual is reconstituted through the liturgical practices
of baptism and Eucharist, theologically, in PNG the body of Christ has AIDS. In order to examine the ways in which the Catholic
Church in PNG has responded faithfully to the Christian body with AIDS, I do so in relation to the three theological virtues
of faith, hope and love.