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1.
Fitting a simplex symmetrically   总被引:1,自引:0,他引:1  
A method for fitting a perfect simplex [Guttman, 1954] is suggested which, in contrast to Kaiser's [1962], is independent of the order of the manifest variables. It is based on a procedure for scaling a set of points from their pairwise distances [Torgerson, 1958; Young & Householder, 1938] which is reviewed in compact notation in the Appendix. The method is extended to an iterative algorithm for fitting a quasi-simplex. Some empirical results are included.This work was done while the author held a Visiting Research Fellowship at the Educational Testing Service. The gracious hospitality of this institution, as well as its scenic surroundings, are beyond praise. An earlier version of this paper (ETS Research Bulletin RB-68-31) was reviewed by Drs. Karl G. Jöreskog and Bruce Bloxom who contributed to its improvement. For a critical reading of the final draft, I owe thanks to Miss Ming-Mei Wang.  相似文献   

2.
The regression trunk approach (RTA) is an integration of regression trees and multiple linear regression analysis. In this paper RTA is used to discover treatment covariate interactions, in the regression of one continuous variable on a treatment variable withmultiple covariates. The performance of RTA is compared to the classical method of forward stepwise regression. The results of two simulation studies, in which the true interactions are modeled as threshold interactions, show that RTA detects the interactions in a higher number of cases (82.3% in the first simulation study, and 52.3% in the second) than stepwise regression (56.5% and 20.5%). In a real data example the final RTA model has a higher cross-validated variance-accounted-for (29.8%) than the stepwise regression model (12.5%). All of these results indicate that RTA is a promising alternative method for demonstrating differential effectiveness of treatments. Supported by The Netherlands Organization for Scientific Research (NWO), grant 030-56403 to Jacqueline Meulman for the Pioneer project “Subject-Oriented Multivariate Analysis,” and grant 451-02-058 to Elise Dusseldorp for the Veni project “Modeling interaction effects as small trees in regression and classification.” We thank Bram Bakker for making the data of his doctoral dissertation available, and David Hand, Jerome Friedman, Bart Jan van Os, Philip Spinhoven, and the anonymous reviewers for their helpful suggestions. Special thanks are due to Lawrence Hubert.  相似文献   

3.
Judith S. Bridges 《Sex roles》1991,24(5-6):291-307
The sex role expectations and rape-supportive beliefs which are differentially applied to date and stranger rape were assessed. A sample of 62 college females and 33 males read one of three rape scenarios which varied according to the victim-perpetrator relationship (steady dating partners/acquaintances on a first date/strangers). Then participants rated the extent to which several sex role expectations and rape-supportive attitudes were applicable to the assault. MANOVAS and univariate ANOVAS showed that females' and males' perceptions of date rape, more than stranger rape, incorporated sex role expectations and that rape-supportive beliefs, primarily of males, were stronger in relation to steady date than first date or stranger rape. These findings are discussed in the context of the sex role analysis of rape.This research was supported by the University of Connecticut Research Foundation Grant #1171-000-22-00215-35-760. The author thanks Laurin Hafner for his help with the data analysis.  相似文献   

4.
The popularity, and subsequent ambiguity, in the use of the term “empowerment” has created an even greater need for reassessment in the applied context than in the theory and research literatures. This paper outlines some of the areas of community, organizational, and societal level social intervention and policy ostensibly based on the concept of empowerment. These include neighborhood voluntary associations (for environmental protection, community crime prevention, etc.), self-help groups, competence-building primary prevention, organizational management, health care and educational reforms, and national and international community service and community development policies. Issues in applying social research to community organizations and to legislative and administrative policy making are reviewed. Ten recommendations are offered, including the value of a dialectical analysis, for helping researchers and policy makers/administrators make more effective use of empowerment theory and research. Humpty Dumpty: “When I use a word, it means just what I choose it to mean neither more nor less.” King of Hearts: “If there's no meaning in it, that saves a world of trouble, you know, as we needn't try to find any.”—Lewis Carroll Portions of this paper were first presented in the program “Empowerment Theory, Research and policy” at the Biennial Conference on Community Research and Action, Williamsburg, Virginia, June 18, 1993. The author thanks Barbara B. Brown, Jo Ann Lippe, Ken Maton and his students, David V. Perkins, Marc A. Zimmerman, and the anonymous reviewers for their very helpful comments on earlier drafts.  相似文献   

5.
A case history is presented of a 70 year old man treated with psychedelic psychotherapy for depression, anxiety, and pain associated with terminal cancer. Interpersonal and intrapersonal aspects of treatment following a single 90 mg dose of dipropyltryptamine (DPT) are described. Comparisons are made between transpersonal, mystical, and religious elements in psychedelic drug experiences and near-death experiences.This paper is based on a study in which the author participated as a research psychotherapist at the Maryland Psychiatric Research Center. The author gives special thanks to the late Dr. T. Glyne Williams for his supervision, and to Dr. Albert A. Kurland for his administrative support of this work, and also thanks Friends of Medical Science Research, the Maryland Psychiatric Research Center, the Maryland Department of Health and Mental Hygiene, and the Mary Reynolds Babcock Foundation for the opportunity to carry out this work.  相似文献   

6.
An important feature of distance-based principal components analysis, is that the variables can be optimally transformed. For monotone spline transformation, a nonnegative least-squares problem with a length constraint has to be solved in each iteration. As an alternative algorithm to Lawson and Hanson (1974), we propose the Alternating Length-Constrained Non-Negative Least-Squares (ALC-NNLS) algorithm, which minimizes the nonnegative least-squares loss function over the parameters under a length constraint, by alternatingly minimizing over one parameter while keeping the others fixed. Several properties of the new algorithm are discussed. A Monte Carlo study is presented which shows that for most cases in distance-based principal components analysis, ALC-NNLS performs as good as the method of Lawson and Hanson or sometimes even better in terms of the quality of the solution. Supported by The Netherlands Organization for Scientific Research (NWO) by grant nr. 030-56403 for the “PIONEER” project “Subject Oriented Multivariate Analysis” to the third author. We would like to thank the anonymous referees for their valuable remarks that have improved the quality of this paper.  相似文献   

7.
8.
Item response theory models posit latent variables to account for regularities in students' performances on test items. Wilson's “Saltus” model extends the ideas of IRT to development that occurs in stages, where expected changes can be discontinuous, show different patterns for different types of items, or even exhibit reversals in probabilities of success on certain tasks. Examples include Piagetian stages of psychological development and Siegler's rule-based learning. This paper derives marginal maximum likelihood (MML) estimation equations for the structural parameters of the Saltus model and suggests a computing approximation based on the EM algorithm. For individual examinees, empirical Bayes probabilities of learning-stage are given, along with proficiency parameter estimates conditional on stage membership. The MML solution is illustrated with simulated data and an example from the domain of mixed number subtraction. The authors' names appear in alphabetical order. We would like to thank Karen Draney for computer programming, Kikumi Tatsuoka for allowing us to use the mixed-number subtraction data, and Eric Bradlow, Chan Dayton, Kikumi Tatsuoka, and four anonymous referees for helpful suggestions. The first author's work was supported by Contract No. N00014-88-K-0304, R&T 4421552, from the Cognitive Sciences Program, Cognitive and Neural Sciences Division, Office of Naval Research, and by the Program Research Planning Council of Educational Testing Service. The second author's work was supported by a National Academy of Education Spencer Fellowship and by a Junior Faculty Research Grant from the Committee on Research, University of California at Berkeley. A copy of the Saltus computer program can be obtained from the second author.  相似文献   

9.
The object of this study was to investigate the effect of differences in format on the precision of teacher ratings and thus on the reliability and validity of two teacher rating scales of children's hyperactive behavior. Teachers (N=242) rated a sample of children in their classrooms using rating scales assessing similar attributes with different formats. For a sub-sample the rating scales were readministered after 2 weeks. The results indicated that improvement can be made in the precision of teacher ratings that may be reflected in improved reliability and validity.This research was supported by grants from the Spencer Foundation and the National Institute of Mental Health (MH 29495). A somewhat different version of this paper was presented at the annual convention of the American Educational Research Association, Toronto, Canada, March 1978. The author thanks Nadine Lambert and Leonard Marascuilo for their assistance in the preparation of this paper.  相似文献   

10.
In this paper we examine a puzzle recently posed by Aaron Preston for the traditional realist assay of property (quality) instances. Consider Socrates (a red round spot) and red1—Socrates’ redness. For the traditional realist, both of these entities are concrete particulars. Further, both involve redness being `tied to’ the same bare individuator. But then it appears that red1 is duplicated in its ‘thicker’ particular (Socrates), so that it can’t be predicated of Socrates without redundancy. According to Preston, this suggests that a concrete particular and its property instances aren’t genuinely related. We argue that Preston’s proffered solution here—to treat property instances as “mental constructs”—is fraught with difficulty. We then go on to show how, by fine-tuning the nature of bare particulars, treating them as abstract modes of things rather than concrete particulars, the traditional realist can neatly evade Preston’s puzzle.
David S. BrownEmail:
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11.
Solomon Feferman 《Synthese》2008,164(3):341-357
Though deceptively simple and plausible on the face of it, Craig’s interpolation theorem (published 50 years ago) has proved to be a central logical property that has been used to reveal a deep harmony between the syntax and semantics of first order logic. Craig’s theorem was generalized soon after by Lyndon, with application to the characterization of first order properties preserved under homomorphism. After retracing the early history, this article is mainly devoted to a survey of subsequent generalizations and applications, especially of many-sorted interpolation theorems. Attention is also paid tomethodological considerations, since the Craig theorem and its generalizations were initially obtained by proof-theoretic arguments while most of the applications are model-theoretic in nature. The article concludes with the role of the interpolation property in the quest for “reasonable” logics extending first-order logic within the framework of abstract model theory. For Bill Craig, with great appreciation for his fundamental contributions to our subject, and for his perennially open, welcoming attitude and fine personality that enhances every encounter.  相似文献   

12.
Rapidly changing estimates on the Soviet régime's ability to survive show how difficult it is for American Sovietologists to grasp what is going on.The paper orginated from a series of informal debates and lunchtable conversations held at the Russian Research Center of Harvard University, over the future of the Soviet regime, around the time of its 50th anniversay. The essay was originally presented as a Russian Research Center Seminar paper on March 20, 1970. The author wishes to express his thanks to Professor Richard Pipes, Director of the Center, for permission to reproduce most of the content of the paper.  相似文献   

13.
Remaining important tasks in finding and developing new drugs and vaccines for HIV/AIDS, malaria, cancer and other diseases require continued industry research and development. Industry’s research and development pipeline has produced drugs that have saved AIDS victims previously facing certain death, but still no cure nor vaccine is yet available. Experience with the process of research and development indicates that it requires more than a decade of development to produce a new drug with costs in the hundreds of millions of dollars. Intellectual property protection is critically important in assuring that drug development continues. Partnerships between industry and the public sector have increased access to new therapies in developing countries and promise to enhance access to both patented and generic medicines in the future. An earlier version of this paper was presented at an international conference, “The Ethics of Intellectual Property Rights and Patents,” held in Warsaw, Poland on 23–24 April, 2004. This paper was prepared with the assistance of Maciej Gajewski, Policy Research Analyst, International Federation of Pharmaceutical Manufacturers Association (IFPMA).  相似文献   

14.
The paper discusses whether there are strictly inexpressible properties. Three main points are argued for: (i) Two different senses of ‘predicate t expresses property p’ should be distinguished. (ii) The property of being a predicate that does not apply to itself is inexpressible in one of the senses of ‘express’, but not in the other. (iii) Since the said property is related to Grelling’s Antinomy, it is further argued that the antinomy does not imply the non-existence of that property.  相似文献   

15.
Conclusions Except for Mowbray, the commentators approach the issue of mental health services quite differently than we do, a fact which may have contributed to some of their misconceptions. Although not stressed in our original report, our view of mental health services is eclectic and pragmatic, encompassing a wide range of psychosocial approaches. We agree with Salem that a range of options needs to be developed and maintained. The motivation for the development of both the ACT and DIC programs was to address the needs of a population neglected by existing mental health services. By contrast, the commentators' agendas converged on the promotion of nonprofessional forms of help-giving. Like the commentators, we have long advocated for consumer choice, self-help groups, and the use of natural supports. Where we part company with them is what we hypothesize would be a minimally sufficient response to over 2 million persons with SMI in the United States. For us, it is not enough to assert that self-help groups might be a partial answer. For us, the self-selection into self-help groups and drop-in centers (which all of the commentators readily acknowledge) leaves open some troubling questions from apolicy standpoint about what happens to those who do not self-select into such groups, especially because we believe that those who select themselves out are likely to include some of the most vulnerable segments of the SMI population. Editor's Note. This paper is an invited reply to several commentaries on an earlier paper by the authors.Preparation of this report was supported in part by Research Scientist Development Award MH 00842-01 from the National Institute of Mental Health to the first author. Our thanks to Debra Pavick for her help in preparing the drop-in center statistics cited in the report.  相似文献   

16.
The following views were presented at the Annual Meeting of the American Association for the Advancement of Science (AAAS) Seminar “Teaching Ethics in Science and Engineering”, 10–11 February 1993 organized by Stephanie J. Bird (M.I.T.), Penny J. Gilmer (Florida State University) and Terrell W. Bynum (Southern Connecticut State University). Opragen Publications thanks the AAAS, seminar organizers and authors for permission to publish extracts from the conference. The opinions expressed are those of the authors and do not reflect the opinions of AAAS or its Board of Directors.  相似文献   

17.
Investing in research is a long-term, risky proposition. In agriculture, it could take fifteen years or more for a research finding to show an improvement in a farmer’s field. Yet, research institutions, like other organizations it needs to be evaluated. For more than twenty years, independent panels of outside experts have evaluated each of the international research centers that the Consultative Group of International Agricultural Research (CGIAR) supports. This paper examines the evolution of this review system, outlines the key methodological challenges faced, and draws lessons for others engaged in evaluating research institutions. It notes that the scope of the CGIAR reviews have been broadened over time in response to users’ concerns. Reviews now cover four dimensions of performance: research results, quality and relevance of research, vision and strategic directions, and management efficiency. The methodological challenges faced in measurement, valuation, and attribution are reviewed, along with practices found to be helpful in addressing these concerns. The paper concludes that the panel approach to institutional evaluation has served CGIAR’s needs well, and recommends it as an evaluation technique for integrating quantitative and qualitative dimensions of institutional performance. His recent work has concentrated on the governance and management of the CGIAR and the individual research centers it supports, including questions of evaluating management effectiveness. Prior to joining the World Bank in 1979, he was Assistant Professor of Political Science at Bogazici University (Istanbul) and Senior Research Director of Systems Research Incorporated (Lansing, Michigan).  相似文献   

18.
This article outlines the means of adaptation by the Polish intelligentsia to the conditions of a free-market (capitalist) system. The ethos of the Polish intelligentsia is at a fundamental level in conflict with the ethos of the middle class. Research conducted in the 1990s into social stratification in Poland clearly showed that it was the intelligentsia that was claiming the best new employment positions that “opened up” along with the market and democracy. Nonetheless, sociologists consider changes in consciousness to be phenomena belonging to the so-called longue durée. For this reason, it has been useful to show how the beneficiaries of the new system are handling the order of norms and values that, while subject to reconstruction, has clear consequences at the level of lifestyle, way of thinking, and means of constructing one’s own biography.  相似文献   

19.
Numerous types of analyses for factorial designs having unequal cell frequencies have been discussed in the literature. These analyses test either weighted or unweighted marginal means which, in turn, correspond to different model comparisons. Previous research has indicated, however, that these analyses result in biased (liberal or conservative) tests when cell variances are heterogeneous. We show how to obtain a generally robust and powerful analysis with any of the recommended nonorthogonal solutions by adapting a modification of the Welch-James procedure for comparing means when population variances are heterogeneous.This research was supported by a Social Sciences and Humanities Research Council (SSHRC) grant (# 410-92-0430) to the first author, a Manitoba Health Research Council Scholar Award and a grant from Natural Sciences and Engineering Research Council to the second author, and a SSHRC Doctoral Fellowship (# 752-92-1628) to the third author. The authors would like to express their gratitude to Joanne Keselman and three anonymous reviewers for their many helpful substantive comments on earlier drafts of this paper.  相似文献   

20.
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