4,282 research outputs found
INDIRECT SAMPLING in the CONTEXT of DUAL FRAME SURVEYS
No full textUnder-coverage is one of the most common problems of sampling frames. To reduce the impact of coverage error on survey estimates several frames can be combined in order to achieve a complete (or nearly complete) coverage of the target population. Multiple frame estimators have been developed to be used in the context of multiple frame surveys. Sampling frames may overlap which is the case when a single unit of the sampling frame is related with more than one element of the target population. Indirect sampling (Lavallée, 1995) is an alternative approach to classical sampling theory in dealing with the overlapping problem of sampling frames on survey estimates. Not infrequently a survey may need more than one sampling frame in order to improve coverage and simultaneously the sampling frame overlap. In this paper a new class of estimators is presented which is the result from merging multiple frames estimators (only the particular case of dual frames will be presented) with indirect sampling estimators in order to bring together in a single estimator the effect of several frames on survey estimates.Indirect Sampling, Generalized Weight Share Method, Dual Frame Surveys
Frame of a pointed finite polyhedral cone.
No full textIn this thesis we develop and test a computational procedure which serves as a pre-processor for algorithms that are used to identify a frame for a pointed finite polyhedral cone generated by a finite set of non-negative vectors. The frame identification algorithms to which we apply our pre-processor are those that test membership in a frame by checking the feasibility of a certain system of linear equations with non-negativity restrictions on the variables. The effect of our pre-processor is two-fold. First, it provides a technique which, we hypothesize, quickly identifies some members of a frame. This avoids the expensive feasibility test for each member so identified. Second, it selects a subset of the generators which, we further hypothesize, is effective in the determination of frame membership of many of the generators through a feasibility check for a much smaller linear system. Our hypotheses are corroborated with some numerical testing. We also show how our pre-processor can be modified to the frame identification problem in Data Envelopment Analysis. These frame elements identify the so called efficient Decision Making Units of an organization. Finally, we use the connection to linear redundancy to suggest how results in that discipline can give further improvements to the frame identification problems.Dept. of Economics, Mathematics, and Statistics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2000 .S51. Source: Masters Abstracts International, Volume: 40-03, page: 0715. Advisers: R. J. Caron; Y. P. Aneja. Thesis (M.Sc.)--University of Windsor (Canada), 2000
Cancer Stem Cells, Models of Study and Implications of Therapy Resistance Mechanisms
No full textThere is now compelling evidence for tumour initiating or cancer stem cells (CSCs) in human cancers. The current evidence of this CSC hypothesis, the CSC phenotype and methods of identification, culture and in vitro modelling will be presented, with an emphasis on prostate cancer. Inherent in the CSC hypothesis is their dual role, as a tumour-initiating cell, and as a source of treatment-resistant cells; the mechanisms behind therapeutic resistance will be discussed. Such resistance is a consequence of the unique CSC phenotype, which differs from the differentiated progeny, which make up the bulk of a tumour. It seems that to target the whole tumour, employing traditional therapies to target bulk populations alongside targeted CSC-specific drugs, provides the best hope of lasting treatment or even cure
The Lightweight Design of a Dump Truck Frame based on Dynamic Responses
No full textThis paper develops a new scheme for the
lightweight design of heavy dump truck frames based on the
characteristics of dynamic responses. The dynamic response
is predicted using a finite element (FE) model which is
verified by an experimental mode analysis. The FE model is
then used to investigate the characteristics of dynamic
responses and frame weight changes with respect to the
mass changes of each frame component for selecting
significant components. An optimization is finally developed
for the lightweight design under constrains that maintain
required dynamic responses and static strength. The
optimization results show that the weight of frame can be
reduced by 8%, showing that the scheme is an effective way
to achieve automotive lightweight design
New Stationary Frame Control Scheme for Three Phase PWM Rectifiers Under Unbalanced Voltage Dips Conditions
No full textA new stationary frame control scheme for three-phase pulsewidth-modulation (PWM) rectifiers operating under unbalanced voltage dips conditions is proposed in this paper. The proposed control scheme regulates the instantaneous active power at the converter poles to minimize the harmonics of the input currents and the output voltage ripple. This paper's novelty is the development of a new current-reference generator implemented directly in stationary reference frame. This allows using proportional sinusoidal signal integrator (P-SSI) controllers for simultaneous compensation of both positive and negative current sequence components. No phase-locked loop (PLL) strategies and coordinate transformations are needed for the proposed current-reference generator. Experimental results are presented for a 20-kV A alternative current (ac)/direct current (dc) converter prototype to demonstrate the effectiveness of the proposed control scheme. A comparison with two other existing control techniques is also performed. Fast dynamic performance with small dc-link voltage ripple and input sinusoidal currents are obtained with this control scheme, even under severe voltage dips operating condition
Using remote vision: The effects of video image frame rate on visual object recognition performance
No full textThis is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.The process of using remote vision was simulated in order to determine the effects of video image frame rate on the performance in visual recognition of stationary environmental hazards in the dynamic video footage of the pedestrian travel environment. The recognition performance was assessed against two different video image frame rate variations: 25 and 2 fps. The assessment included a range of objective and subjective criteria. The obtained results show that the effects of the frame rate variations on the performance are statistically insignificant. This paper belongs to the process of development of a novel system for navigation of visually impaired pedestrians. The navigation system includes a remote vision facility, and the visual recognition of the environmental hazards by the sighted human guide is a basic activity in aiding the visually impaired user of the system in mobility
Cult Author versus Literary Celebrity: Commentary of and on Janet Frame and Margaret Atwood
No full text'Cult Author versus Literary Celebrity: Commentary of and on Janet Frame and Margaret Atwood' is a comparative exploration of authorial commentary and the critical interaction with that commentary. The mythology that surrounds an author is a powerful force. It can affect and inform critical interpretations of their fiction. The way that authors participate in and attempt to shape their mythologies therefore has implications for the body of literary criticism that attaches to their work. This meta-critical study charts the nature and magnitude of the commentary produced by New Zealand author Janet Frame and Canadian author Margaret Atwood. It aims to investigate how each author has intervened as an active agent to mould the mythological discourse that surrounds them, and to examine the effect of each author's commentary by ascertaining where it has influenced overarching critical narratives of their work. The use of the authors' commentary as a critical tool is canvassed, as is critical reaction to the personae each author projects through their commentary
Sulky Frame for Agricultural Implements.
No full textPatent for "a new and improved sulky-frame adapted for the attachment of several agricultural implements and provided with means for elevating or lowering the frame and the implement thereto attached, whereby the latter is brought in contact with the soil or elevated above such contact." (Lines 16-23) Includes instructions and illustrations
In search of coherence and consistency in European contract law: a way forward
No full textIn 2001 the European Commission began a far reaching consultation to ascertain whether obstacles arise for the proper functioning of the internal market and for crossborder trade from the existing divergent and fragmentary state of European contract law at the EU and national levels. This question was answered in the affirmative. Action was needed to simplify the regulatory environment for cross-border trade; to provide businesses and consumers with a single, comprehensive, and directly applicable contractual framework for cross-border transactions in the internal market. This thesis offers a solution to the current obstacles to cross-border trade on the basis of the Commission’s principal proposals for future action; the review of the acquis communautaire, the creation of a Common Frame of Reference, and the adoption of optional instruments of European contract law. It undertakes a chronological and critical assessment of the proposals and progress to date, in order to determine the most appropriate way forward for European contract law. It seeks to do so against a wider debate which highlights the economic, socio-cultural and political issues and interests which bear on the suitability and desirability of the Commission’s proposals and which must be accommodated within the final response. It also draws on existing examples of trade regulation, in particular, harmonised instruments, which share the objective of facilitating cross-border trade, at the international level. Such examination assists the understanding of the regulatory approach that must be taken to European contract law, and more particularly determines the extent to which the objectives of action at the European level can be realised within the internal market. It is against this background, and at a time when the EU is looking to the internal market, and the facilitation of cross-border trade as a means for Europe to emerge from economic crisis, that this thesis presents necessary action for the immediate development of the European contract law project. It concludes that the adoption of optional instruments present the most appropriate way forward. This is not, however, an absolute solution. The review of the acquis and the resulting proposal for a Consumer Rights Directive has an integral part to play moving forward. In search of coherence and consistency in European contract law however the CFR, both as a legislative toolbox and basis for the optional instruments, must underpin the future regulatory response. It is clear that all three of the Commission’s proposals must figure in the way forwar
Frame-by-frame observations of structure fluctuations in single mass-selected Au clusters using aberration-corrected electron microscopy
No full textThe multi-dimensional potential energy surface (PES) of a nanoparticle, such as a bare cluster of metal atoms, controls both the structure and dynamic behaviour of the particle. These properties are the subject of numerous theoretical simulations. However, quantitative experimental measurements of critical PES parameters are needed to regulate the models employed in the theoretical work. Experimental measurements of parameters are currently few in number, while model parameters taken from bulk systems may not be suitable for nanosystems. Here we describe a new measurement methodology, in which the isomer structures of a single deposited nanocluster are obtained frame-by-frame in an aberration-corrected scanning transmission electron microscope (ac-STEM) in high angle annular dark field (HAADF) mode. Several gold clusters containing 309 ± 15 atoms were analysed individually after deposition from a mass-selected cluster source onto an amorphous carbon film. The main isomers identified are icosahedral (Ih), decahedral (Dh) and face-centred-cubic (fcc) (the bulk structure), alongside many amorphous (glassy) structures. The results, which are broadly consistent with static ac-STEM measurements of an ensemble of such clusters, open the way to dynamic measurements of many different nanoparticles of diverse sizes, shapes and compositions
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