67,189 research outputs found

    A uniform functional law of the logarithm for the local empirical process

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    We prove a uniform functional law of the logarithm for the local empirical process. To accomplish this we combine techniques from classical and abstract empirical process theory, Gaussian distributional approximation and probability on Banach spaces. The body of techniques we develop should prove useful to the study of the strong consistency of d-variate kernel-type nonparametric function estimators.Comment: Published by the Institute of Mathematical Statistics (http://www.imstat.org) in the Annals of Probability (http://www.imstat.org/aop/) at http://dx.doi.org/10.1214/00911790400000024

    Business angel investing

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    Business angels are conventionally defined as high net worth individuals who invest their own money, along with their time and expertise, directly in unquoted companies in which they have no family connection, in the hope of financial gain. The term angel was coined by Broadway insiders in the early 1900s to describe wealthy theatre-goers who made high risk investments in theatrical productions. Angels invested in these shows primarily for the privilege of rubbing shoulders with the theatre personalities that they admired. The term business angel was given to those individuals who perform essentially the same function in a business context (Benjamin and Margulis, 2000: 5). There is a long tradition of angel investing in businesses (Sohl, 2003). Moreover, angel investing is now an international phenomenon, found in all developed economies and now diffusing to emerging economies such as China (Lui Tingchi, and Chen Po Chang,, 2007). However, it has only attracted the attention of researchers since the 1980s

    Using Technology as a Vehicle to Appropriately Integrate Mathematics and Science Instruction for the Middle School

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    At the College of William and Mary, pre-service middle school science and mathematics teachers enroll in their respective methods courses taught in the same time period. Both instructors emphasize the importance of the content pedagogy unique to their disciplines in their individual courses such as strategies for teaching problem solving, computation, proportional reasoning, algebraic and geometric thinking in mathematics, and strategies for teaching students how to investigate or design and conduct experiments in science. However, the two classes come together for sessions in which they examine the relationship of the two disciplines and the proper role of technology, both graphing calculator and computer, in their instruction Starting with resources such as Science in Seconds for Kids by Jean Potter [1], the science students collaborate with the math students to design and conduct brief experiments. The data generated is analyzed using spreadsheets and later graphing calculators. Various classes of mathematical curves are examined using data generated by sensors/probes and CBLs. Through this experience the pre-service teachers learn to work collaboratively with their colleagues on meaningful tasks, strengthening the effectiveness of all participants

    CELSS scenario analysis: Breakeven calculations

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    A model of the relative mass requirements of food production components in a controlled ecological life support system (CELSS) based on regenerative concepts is described. Included are a discussion of model scope, structure, and example calculations. Computer programs for cultivar and breakeven calculations are also included

    Experimental Design at the Intersection of Mathematics, Science, and Technology in Grades K-6

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    Interdisciplinary courses, highlighting as they do the area(s) the disciplines have in common, often give the misperception of a single body of knowledge and/or way of knowing. However, discipline based courses often leave the equally mistaken notion that the disciplines have nothing in common. The task of the methods courses described in this paper is to reach an appropriate balance so that our pre-service elementary (K-6) teachers have a realistic perception of the independence and interdependence of mathematics and science. At the College of William and Mary each cohort of pre-service elementary teachers enrolls in mathematics and science methods courses taught in consecutive hours. Both instructors emphasize the importance of the content pedagogy unique to their disciplines such as strategies for teaching problem solving, computation, algebraic thinking, and proportional reasoning in mathematics and strategies for teaching students how to investigate and understand the concepts of science. The instructors model interdisciplinary instruction by collaboratively teaching common content pedagogy such as the use of technology, data analysis, and interpretation. Students also identify real-life application of the mathematical principles they are learning that can be applied to science. The concept of simultaneously teaching appropriately selected math and science skills are stressed. Given this approach students are not left with the notion that mathematics is the handmaid of science nor the notion that it is the queen of the sciences. Rather, they view mathematics as a co-equal partner

    On the Breiman conjecture

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    Let Y1,Y2,Y_{1},Y_{2},\ldots be positive, nondegenerate, i.i.d. GG random variables, and independently let X1,X2,X_{1},X_{2},\ldots be i.i.d. FF random variables. In this note we show that whenever XiYi/Yi\sum X_{i}Y_{i}/\sum Y_{i} converges in distribution to nondegenerate limit for some FFF\in \mathcal{F}, in a specified class of distributions F\mathcal{F}, then GG necessarily belongs to the domain of attraction of a stable law with index less than 1. The class F\mathcal{F} contains those nondegenerate XX with a finite second moment and those XX in the domain of attraction of a stable law with index 1<α<21<\alpha <2

    Couplings and Strong Approximations to Time Dependent Empirical Processes Based on I.I.D. Fractional Brownian Motions

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    We define a time dependent empirical process based on nn i.i.d.~fractional Brownian motions and establish Gaussian couplings and strong approximations to it by Gaussian processes. They lead to functional laws of the iterated logarithm for this process.Comment: To appear in the Journal of Theoretical Probability. 37 pages. Corrected version. The results on quantile processes are taken out and it will appear elsewher

    A note on a maximal Bernstein inequality

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    We show somewhat unexpectedly that whenever a general Bernstein-type maximal inequality holds for partial sums of a sequence of random variables, a maximal form of the inequality is also valid.Comment: Published in at http://dx.doi.org/10.3150/10-BEJ304 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

    The limit distribution of ratios of jumps and sums of jumps of subordinators

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    Let VtV_{t} be a driftless subordinator, and let denote mt(1)mt(2)m_{t}^{(1)} \geq m_{t}^{(2)} \geq\ldots its jump sequence on interval [0,t][0,t]. Put Vt(k)=Vtmt(1)mt(k)V_{t}^{(k)} = V_{t} - m_{t}^{(1)} - \ldots- m_{t}^{(k)} for the kk-trimmed subordinator. In this note we characterize under what conditions the limiting distribution of the ratios Vt(k)/mt(k+1)V_{t}^{(k)} / m_{t}^{(k+1)} and mt(k+1)/mt(k)m_{t}^{(k+1)} / m_{t}^{(k)} exist, as t0t \downarrow0 or tt \to\infty.Comment: 14 page
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