4,559 research outputs found

    Wiener Chaos and the Cox-Ingersoll-Ross model

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    In this we paper we recast the Cox--Ingersoll--Ross model of interest rates into the chaotic representation recently introduced by Hughston and Rafailidis. Beginning with the ``squared Gaussian representation'' of the CIR model, we find a simple expression for the fundamental random variable X. By use of techniques from the theory of infinite dimensional Gaussian integration, we derive an explicit formula for the n-th term of the Wiener chaos expansion of the CIR model, for n=0,1,2,.... We then derive a new expression for the price of a zero coupon bond which reveals a connection between Gaussian measures and Ricatti differential equations.Comment: 27 page

    Quasars as very-accurate clock synchronizers

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    Quasars can be employed to synchronize global data communications, geophysical measurements, and atomic clocks. It is potentially two to three orders of magnitude better than presently-used Moon-bounce system. Comparisons between quasar and clock pulses are used to develop correction or synchronization factors for station clocks

    Models for Anchoring and Acquiescence Bias in Consumption Data

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    Item non-response in household survey data on economic variables such as income, assets or consumption is a well-known problem.Follow-up unfolding bracket questions have been used as a tool to collect partial information on respondents that do not answer an open-ended question.It is also known, however, that mistakes are made in answering such unfolding bracket questions.In this paper, we develop several limited dependent variable models to analyze two sources of mistakes, anchoring and acquiescence (or yeasaying), focusing on the first bracket question.We use the experimental module of the AHEAD 1995 data, where the sample is randomly split into respondents who get an open-ended question on the amount of total family consumption - with follow-up unfolding brackets (of the form: is consumption Xormore?)forthosewhoanswerdontknoworrefuseandrespondentswhoareimmediatelydirectedtounfoldingbrackets.Inbothcases,theentrypointoftheunfoldingbracketsequenceisrandomized.WecomparemodelsinwhichtheprobabilityofamistakedependsonthedeviationbetweenthetrueconsumptionamountandtheentrypointamountX or more?) for those who answer don t know or refuse - and respondents who are immediately directed to unfolding brackets.In both cases, the entry point of the unfolding bracket sequence is randomized.We compare models in which the probability of a mistake depends on the deviation between the true consumption amount and the entry point amount X and models in which it does not.We find that allowing for acquiescence bias substantially changes the conclusions on the selective nature of non-response to the open-ended question and on the distribution of consumption expenditures in the population.Once acquiescence bias is taken into account, anchoring in the first bracket question plays only a minor role.consumption;household economics;distribution;nonresponse

    A Test for Anchoring and Yea-Saying in Experimental Consumption Data

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    In the experimental module of the AHEAD 1995 data, the sample is randomly split into respondents who get an open-ended question on the amount of total family consumption - with follow-up unfolding brackets (of the form: is consumption $X or more?) for those who answer don t know or refuse - and respondents who are immediately directed to unfolding brackets.In both cases, the entry point of the unfolding bracket sequence is randomized.These data are used to develop a nonparametric test for whether people make mistakes in answering the first bracket question, allowing for any type of selection into answering the open-ended question or not.Two well-known types of mistakes are considered: anchoring and yea-saying (or acquiescence).While the literature provides ample evidence that the entry point in the first bracket question serves as an anchor for follow-up bracket questions, it is less clear whether the answers to the first bracket question are already affected by anchoring.We reject the joint hypothesis of no anchoring and no yea-saying at the entry point.Once yea-saying is taken into account, there is no evidence of anchoring.consumption;nonresponse

    Asymmetric field dependence of magnetoresistance in magnetic films

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    We study an asymmetric in field magnetoresistance that is frequently observed in magnetic films and, in particular, the odd longitudinal voltage peaks that appear during magnetization reversal in ferromagnetic films, with out-of-plane magnetic anisotropy. We argue that the anomalous signals result from small variation of magnetization and Hall resistivity along the sample. Experimental data can be well described by a simple circuit model, the latter being supported by analytic and numerical calculations of current and electric field distribution in films with a gradual variation of the magnetization and Hall resistance.Comment: 7 pages, 5 figures, to be published in Phys. Rev.

    Superconducting d-wave junctions: The disappearance of the odd ac components

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    We study voltage-biased superconducting planar d-wave junctions for arbitrary transmission and arbitrary orientation of the order parameters of the superconductors. For a certain orientation of the superconductors the odd ac components disappear, resulting in a doubling of the Josephson frequency. We study the sensitivity of this disappearance to orientation and compare with experiments on grain boundary junctions. We also discuss the possibility of a current flow parallel to the junction.Comment: 5 pages, 3 figure

    Image selection system

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    An image selection (ISS) was developed for the NASA-Ames Research Center Earth Resources Aircraft Project. The ISS is an interactive, graphics oriented, computer retrieval system for aerial imagery. An analysis of user coverage requests and retrieval strategies is presented, followed by a complete system description. Data base structure, retrieval processors, command language, interactive display options, file structures, and the system's capability to manage sets of selected imagery are described. A detailed example of an area coverage request is graphically presented
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