1,015 research outputs found

    Weltanschauung

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    Thalidomide babies and syphilitic old men are beautiful yes, because we know who made them so all glory to His name..

    CONFIDENCE INTERVALS FOR VARIANCE COMPONENTS IN ONE-WAY UNBALANCED DESIGNS

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    Consider the one way unbalanced components of variance model given by Yij = μ + Ai + Eij, (i = l, ... ,a, j = l, ... ,bi) where μ is an unknown constant parameter, Ai and Eij are independent normal random variables with zero means and variances σ2A and σ2E respectively, The problem is to obtain a confidence interval for σ2A with confidence coefficient greater than or equal to a specified 1 - α. Three new procedures for obtaining confidence intervals for σ2A are examined. These new methods are derived using unweighted means. These three methods are compared with a standard procedure based on confidence coefficients and expected widths .

    Generalised Probabilistic Control Design for Uncertain Stochastic Control Systems

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    In this paper a novel generalised fully probabilistic controller design for the minimisation of the Kullback-Leibler divergence between the actual joint probability density function (pdf) of the closed loop control system, and an ideal joint pdf is presented for a linear Gaussian uncertain class of stochastic systems. A single layer neural network is used to approximate the probability density function of the system dynamics. The generalised probabilistic control law is obtained by solving the recurrence equation of dynamic programming to the fully probabilistic design control problem while taking into consideration the dependency of the parameters of the estimated probability density function of the system dynamics on the input values. It is shown to be of the class of cautious type controllers which accurately minimises the value of the Kullback-Leibler divergence without disregarding the variance of the model prediction as an element to be minimised. Comparison of theoretical and numerical results obtained from the F-16 fighter aircraft application with existing state-of-the-art demonstrates the effectiveness of the proposed method

    On quadratic estimates of variance components

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    Quadratic estimates of variance components for various linear models were investigated;For the general balanced nested classification with no specific distributions assumed, it was shown that the quadratic estimate which was unbiased and which had minimum variance was given by the analysis of variance method of estimating the variance components;For the one fold classification with unequal numbers the model is yij=m+ai+bij where E ai2 = sigma a2; E bij2 = sigma 2;The best quadratic unbiased estimate of sigmaa2 depends on sigma2 and sigmaa2. Under the above model with the additional assumptions E ai 4 = 3 sigmaa4 and E bij 4 = 3 sigma4 the quadratic estimation of sigma a2 was investigated. Two methods of estimation were given, and a method of determining a lower bound on the efficiency of each method was given if w = sigmaa2/sigma2 is known. It is believed in most cases when w \u3e .01, that one of these two methods will give an efficiency above 80 percent;For the general balanced cross classification with normality assumptions it was shown that the best quadratic unbiased estimate of the variance components is given by the analysis of variance method of estimating variance components. It was also shown that the best quadratic unbiased estimate of any linear combination of variance components is given by the same linear combination of the best quadratic unbiased estimates of the individual variance components

    Thrust and torque response for drilling titanium and carbon composite sandwich materials [abstract]

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    Abstract only availableExperiments were conducted based upon previous research conducted by El-Gizawy and Khasawneh [1] to determine the time response of thrust force and torque correlated to a simple drilling procedure through carbon fiber reinforced epoxy (IM7/997-3) composite material over 6Al-4V titanium alloy (AB1) sheets. The experiments measured the time response with a thrust and torque sensor, data acquisition system and CNC drilling machine. The research was used to locate points of interest among the previous statistical setup. Three-dimensional surfaces were analyzed to determine the drilling parameters that cause the highest force and torque in the CNC spindle (and, therefore, the drill bit) and the lowest force and torque, within the range available with the CNC used in the experimental setup. The experimental holes were also analyzed via surface profilometer and coordinate measurement probe to obtain surface roughness and dimensional accuracy measurements. The data indicates that the parameters that cause lower force and torque are preferable for dimensional accuracy in the titanium as well as for surface roughness, and tool life.College of Engineering Undergraduate Research Optio

    Incorporating Science into the Environmental Policy Process: a Case Study from Washington State

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    The incorporation of science into environmental policy is a key concern at many levels of decision making. Various institutions have sought to standardize the protection of natural resources by requiring that decisions be made based on the best available science. Here we present empirical data describing the incorporation of best available science in the land-use policy process on a local scale. Results are based on interviews with planners and others who conducted scientific reviews associated with a Washington State Growth Management Act amendment that requires the inclusion of best available science in protecting critical areas. Our results show that jurisdictions varied with respect to how they included science in their land-use policies. Specifically, we found that smaller jurisdictions were very reliant on scientific information provided by state agencies, communicated frequently with other jurisdictions and agencies, and most often let scientific information guide the policy development process. Medium-sized jurisdictions, in contrast, were more inwardly focused, relied predominantly on local information, communicated little with outsiders, and more often looked to political influences to guide the policy process. Large jurisdictions, including most counties, often generated their own best science, communicated with and often informed state agencies and other jurisdictions, and more often considered science first during the policy development process. Jurisdictions also differed in terms of how best available science was defined, and how jurisdictions dealt with conflicting scientific information. Our results provide empirical evidence of the variation with which best available science is used in environmental policies

    Dealing with a traumatic past: the victim hearings of the South African truth and reconciliation commission and their reconciliation discourse

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    In the final years of the twentieth and the beginning of the twenty-first century, there has been a worldwide tendency to approach conflict resolution from a restorative rather than from a retributive perspective. The South African Truth and Reconciliation Commission (TRC), with its principle of 'amnesty for truth' was a turning point. Based on my discursive research of the TRC victim hearings, I would argue that it was on a discursive level in particular that the Truth Commission has exerted/is still exerting a long-lasting impact on South African society. In this article, three of these features will be highlighted and illustrated: firstly, the TRC provided a discursive forum for thousands of ordinary citizens. Secondly, by means of testimonies from apartheid victims and perpetrators, the TRC composed an officially recognised archive of the apartheid past. Thirdly, the reconciliation discourse created at the TRC victim hearings formed a template for talking about a traumatic past, and it opened up the debate on reconciliation. By discussing these three features and their social impact, it will become clear that the way in which the apartheid past was remembered at the victim hearings seemed to have been determined, not so much by political concerns, but mainly by social needs

    Vertical Artifacts in High-Resolution WorldView-2 and Worldview-3 Satellite Imagery of Aquatic Systems

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    Satellite image artefacts are features that appear in an image but not in the original imaged object and can negatively impact the interpretation of satellite data. Vertical artefacts are linear features oriented in the along-track direction of an image system and can present as either banding or striping; banding are features with a consistent width, and striping are features with inconsistent widths. This study used high-resolution data from DigitalGlobeʻs (now Maxar) WorldView-3 satellite collected at Lake Okeechobee, Florida (FL), on 30 August 2017. This study investigated the impact of vertical artefacts on both at-sensor radiance and a spectral index for an aquatic target as WorldView-3 was primarily designed as a land sensor. At-sensor radiance measured by six of WorldView-3ʻs eight spectral bands exhibited banding, more specifically referred to as non-uniformity, at a width corresponding to the multispectral detector sub-arrays that comprise the WorldView-3 focal plane. At-sensor radiance measured by the remaining two spectral bands, red and near-infrared (NIR) #1, exhibited striping. Striping in these spectral bands can be attributed to their time delay integration (TDI) settings at the time of image acquisition, which were optimized for land. The impact of vertical striping on a spectral index leveraging the red, red edge, and NIR spectral bands—referred to here as the NIR maximum chlorophyll index (MCINIR)—was investigated. Temporally similar imagery from the European Space Agencyʻs Sentinel-3 and Sentinel-2 satellites were used as baseline references of expected chlorophyll values across Lake Okeechobee as neither Sentinel-3 nor Sentinel-2 imagery showed striping. Striping was highly prominent in the MCINIR product generated using WorldView-3 imagery, as noise in the at-sensor radiance exceeded any signal of chlorophyll in the image. Adjusting the image acquisition parameters for future tasking of WorldView-3 or the functionally similar WorldView-2 satellite may alleviate these artefacts. To test this, an additional WorldView-3 image was acquired at Lake Okeechobee, FL, on 26 May 2021 in which the TDI settings and scan line rate were adjusted to improve the signal-to-noise ratio. While some evidence of non-uniformity remained, striping was no longer noticeable in the MCINIR product. Future image tasking over aquatic targets should employ these updated image acquisition parameters. Since the red and NIR #1 spectral bands are critical for inland and coastal water applications, archived images not collected using these updated settings may be limited in their potential for analysis of aquatic variables that require these two spectral bands to derive
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