bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shared scientific thinking in everyday parent‐child activity
Authors: Crowley Kevin , Callanan Maureen A. , Jipson Jennifer L. , Galco Jodi , Topping Karen , Shrager Jeff 
Published: August 2002

AbstractCurrent accounts of the development of scientific reasoning focus on individual children's ability to coordinate the collection and evaluation of evidence with the creation of theories to explain the evidence. This observational study of parent–child interactions in a children's museum demonstrated that parents shape and support children's scientific thinking in everyday, nonobligatory activity. When children engaged an exhibit with parents, their exploration of evidence was observed to be longer, broader, and more focused on relevant comparisons than children who engaged the exhibit without their parents. Parents were observed to talk to children about how to select and encode appropriate evidence and how to make direct comparisons between the most informative kinds of evidence. Parents also sometimes assumed the role of explainer by casting children's experience in causal terms, connecting the experience to prior knowledge, or introducing abstract principles. We discuss these findings with respect to two dimensions of children's scientific thinking: developments in evidence collection and developments in theory construction. © 2001 John Wiley & Sons, Inc.Sci Ed85:712–732, 2001.
Tracking the processes of change in US undergraduate education in science, mathematics, engineering, and technology
Authors: Seymour Elaine 
Published: August 2002

AbstractThis paper describes some features in the changing landscape of activities intended to improve both quality and access in science, mathematics, engineering, and technology (SMET) undergraduate education. Observations are offered from the viewpoint afforded by my work—broadly over the last 10 years—both as a researcher, and as an evaluator for projects related to the improvement of undergraduate SMET education. Over that period, I have watched the landscape change—some issues, at first prominent, have diminished in importance; some are emergent; and yet others lie on the horizon. I have also observed that actions in pursuit of various reform goals reflect a variety of theories about how change can be accomplished that are not necessarily complementary. This short history of shifts in the focus of our efforts, and in our beliefs about how they may be achieved, is offered as a framework for discussion of these nationwide endeavors and as an aid in considering next steps. © 2001 John Wiley & Sons, Inc. Sci Ed 86:79–105, 2001.
Design of a high‐speed RSA encryption processor based on the residue table for redundant binary numbers
Authors: Tomabechi Nobuhiro , Ito Teruki 
Published: August 2002

AbstractThe RSA cryptosystem plays an important role in ensuring the security of network communications, although it has the drawback that much time is required for encryption/decryption. This paper presents a high‐speed RSA encryption processor employing highly parallel operation based as much as possible in the hardware technology as follows: (1) All of the arithmetic circuits required for encryption/decryption are implemented in the form of redundant binary numbers. (2) Residue calculation is performed by table look‐up in a hardware table built in the processor. The table look‐up is done in the form of redundant binary numbers. The operation speed of the proposed processor is found to be 60 times that of usual processors when the key lengthNis 1024 bits. Also, the order of the encryption time of the processor isO(NlogN). The chip size of the processor is estimated as (4.3 × 105λ) × (5.63 × 105λ), where λ denotes the standard size in the layout design. The chip size becomes 10.9 cm × 14.1 cm when the 0.5−µm rule, which corresponds to λ = 0.25 µm, is used, hence the processor can be integrated on an 8‐inch wafer. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(5): 1–10, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1122
Differences of speech rate, interphoneme distance and likelihood caused by speaking style, their relationship, and recognition performance
Authors: Yamamoto Kazumasa , Nakagawa Seiichi 
Published: August 2002

AbstractWe have been developing a speech recognition system as part of a spoken dialogue system. There is a clear limit of recognition performance for dialogue speech using acoustic models built with a read speech database, mainly because various acoustic and linguistic phenomena, which reflect the characteristics of spontaneous speech, occur in dialogue speech. We made acoustic models of syllable unit using simulated dialogue speech or read speech database. We then analyzed the acoustic properties of the dialogue speech in terms of the distance between models and the distribution of duration and compared them with read speech. We found that the speech rate of dialogue speech was faster on average and had a greater variance of speech rate than read speech. We also found that the distance between vowels of the dialogue speech tended to be smaller than that of read speech, that is, the vowels tend to be confused in dialogue speech because of closer boundaries to one another. We also compared recognition performance using acoustic models trained with each database and found that dialogue speech had a low correct syllable rate. Dialogue speech was more prone to insertion and deletion errors and the influence of distance between vowels and the variance of speech rate was shown clearly in the results. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(7): 50–60, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1141
Understanding and managing innovation processes
Authors: Milling Peter M. 
Published: August 2002

AbstractThe lecture was delivered at the Prize ceremony during the 19th International Conference of the System Dynamics Society in Atlanta, Georgia. It summarizes the Award winning article, published in the 1996 issue of System Dynamics Review, and discusses subsequent work. Comprehensive citations and quotations are found in the original publications. Shortened product life cycles, tight competition, and resource intensive research and development are some of the parameters that make innovation management a highly challenging endeavor. To succeed in such an environment, a solid understanding of the observed and the expected behavior is indispensable and can effectively be supported by modeling the object under investigation. The article analyzes strategies for new products, especially price strategies, and includes the processes of research and development in a comprehensive model, which then is disaggregated to explicitly take into consideration the actions of different competitors. Finally, a multi‐person gaming version is presented. The article concludes with some thoughts about complexity, its dimensions and its challenges for system dynamics. Copyright © 2002 John Wiley & Sons, Ltd.
Standardization using the harmonically weighted ratios: internal and external comparisons
Authors: Lee Wen‐Chung 
Published: August 2002

AbstractStandardization of rates is a basic tool for epidemiologists. The most frequently used methods are the ‘direct standardization’ (with summary index of comparative mortality figure, CMF) and the ‘indirect standardization’ (with summary index of standardized mortality ratio, SMR). The CMF facilitates a valid comparison between populations or across time periods, yet, it suffers from the problem of instability. By contrast, the SMR is stable and can be used for external comparison. However, it cannot guarantee a valid internal comparison. In this paper, the author proposes a new standardized measure, the ‘harmonically weighted ratio’ (HWR). The HWR can be used for external as well as internal comparisons – with the assumption of rate‐ratio homogeneity, or with heterogeneity but dominance of one population over another. Simulation shows that its performance in terms of pairwise comparisons is the best among the three methods or compares favourably to that of the SMR. The author also examines the behaviours of the HWR when used for hypothesis testing (the ‘HWR test’). The HWR can be considered for standardization when the purpose of the standardization is solely for comparison and when the universe of the comparisons can be clearly defined. Copyright © 2002 John Wiley & Sons, Ltd.
A Bayesian analysis of bivariate ordinal data: Wisconsin epidemiologic study of diabetic retinopathy revisited
Authors: Biswas Atanu , Das Kalyan 
Published: August 2002

AbstractIn many biomedical experiments one may often encounter bivariate data which are componentwise ordinal. The data set of the ophthalmologic experiment of the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) is an example of such data. Several authors considered the analysis of such data from different viewpoints. The present work reviews the existing literature based on the WESDR data and on the basis of some latent variables provide the technique for analysing such data more easily in a Bayesian framework. Computation supports the methodology to a great extent. A comparison between our approach and the likelihood based approach considered by Kim has also been made. Copyright © 2002 John Wiley & Sons, Ltd.
Tests for equivalence or non‐inferiority for paired binary data
Authors: Liu Jen‐pei , Hsueh Huey‐miin , Hsieh Eric , Chen James J. 
Published: August 2002

AbstractAssessment of therapeutic equivalence or non‐inferiority between two medical diagnostic procedures often involves comparisons of the response rates between paired binary endpoints. The commonly used and accepted approach to assessing equivalence is by comparing the asymptotic confidence interval on the difference of two response rates with some clinical meaningful equivalence limits. This paper investigates two asymptotic test statistics, a Wald‐type (sample‐based) test statistic and a restricted maximum likelihood estimation (RMLE‐based) test statistic, to assess equivalence or non‐inferiority based on paired binary endpoints. The sample size and power functions of the two tests are derived. The actual type I error and power of the two tests are computed by enumerating the exact probabilities in the rejection region. The results show that the RMLE‐based test controls type I error better than the sample‐based test. To establish an equivalence between two treatments with a symmetric equivalence limit of 0.15, a minimal sample size of 120 is needed. The RMLE‐based test without the continuity correction performs well at the boundary point 0. A numerical example illustrates the proposed procedures. Copyright © 2002 John Wiley & Sons, Ltd.
Discovering subpopulation structure with latent class mixed models
Authors: McCulloch C. E. , Lin H. , Slate E. H. , Turnbull B. W. 
Published: August 2002

AbstractThe linear mixed model is a well‐known method for incorporating heterogeneity (for example, subject‐to‐subject variation) into a statistical analysis for continuous responses. However heterogeneity cannot always be fully captured by the usual assumptions of normally distributed random effects. Latent class mixed models offer a way of incorporating additional heterogeneity which can be used to uncover distinct subpopulations, to incorporate correlated non‐normally distributed outcomes and to classify individuals. The methodology is motivated with examples in health care studies and a detailed illustration is drawn from the Nutritional Prevention of Cancer trials. Latent class models are used with longitudinal data on prostate specific antigen (PSA) as well as incidence of prostate cancer. The models are extended to accommodate prostate cancer as a survival endpoint; this is compared to treating it as a binary endpoint. Four subpopulations are identified which differ both with regard to their PSA trajectories and their incidence rates of prostate cancer. Copyright © 2002 John Wiley & Sons, Ltd.
Estimating risk and rate levels, ratios and differences in case‐control studies
Authors: King Gary , Zeng Langche 
Published: August 2002

AbstractClassic (or ‘cumulative’) case‐control sampling designs do not admit inferences about quantities of interest other than risk ratios, and then only by making the rare events assumption. Probabilities, risk differences and other quantities cannot be computed without knowledge of the population incidence fraction. Similarly, density (or ‘risk set’) case‐control sampling designs do not allow inferences about quantities other than the rate ratio. Rates, rate differences, cumulative rates, risks, and other quantities cannot be estimated unless auxiliary information about the underlying cohort such as the number of controls in each full risk set is available. Most scholars who have considered the issue recommend reporting more than just risk and rate ratios, but auxiliary population information needed to do this is not usually available. We address this problem by developing methods that allow valid inferences about all relevant quantities of interest from either type of case‐control study when completely ignorant of or only partially knowledgeable about relevant auxiliary population information. Copyright © 2002 John Wiley & Sons, Ltd.
On the use of Cox regression in the presence of an irregularly observed time‐dependent covariate
Authors: de Bruijne Mattheus H. J. , le Cessie Saskia , Kluin‐Nelemans Hanneke C. , van Houwelingen Hans C. 
Published: August 2002

AbstractWe consider the joint modelling of longitudinal and event time data. The longitudinal data are irregularly collected and the event times are subject to right censoring. Most methods described in the literature are quite complex and do not belong to the standard statistical tools. We propose a more practical approach using Cox regression with time‐dependent covariates. Since the longitudinal data are observed irregularly, we have to account for differences in observation frequency between individual patients. Therefore, the time elapsed since last observation (TEL) is added to the model. TEL and its interaction with the time‐dependent covariate show a strong effect on the hazard. The latter indicates that older recordings have less impact than recent recordings. Pros and cons of this methodology are discussed and a simulation study is performed to study the effect of TEL on the hazard. The fitted Cox model serves as a starting point for the prediction of future patient's events. Our method is applied to a study on chronic myeloid leukaemia (CML) with longitudinal white blood cell counts (WBC) as time‐dependent covariate and patient's death as event. Copyright © 2001 John Wiley & Sons, Ltd.
Modelling cause‐specific hazards with radial basis function artificial neural networks: application to 2233 breast cancer patients
Authors: Boracchi Patrizia , Biganzoli Elia , Marubini Ettore 
Published: August 2002

AbstractThe clinical course of a disease is often characterized by the possible occurrence of different types of events acting in a competing way. From a statistical point of view this translates into the need of modelling the dependence of cause‐specific hazards as a function of covariates. Generalized linear models with Poisson error have previously been adopted for the analysis of competing risks as a function of discrete covariates. In the present paper an artificial neural network extension for the flexible joint estimation of cause‐specific hazards depending on both discrete and continuous covariates is proposed. This approach is based on radial basis function networks which have the advantage of allowing parameter estimation by the adoption of standard software for generalized linear models. We have applied this method to data from 2233 breast cancer patients to investigate the effects of age, tumour size, number of metastatic axillary nodes, histology and tumour site on cause‐specific hazards for intra‐breast tumour recurrences and distant metastases. The adoption of a radial basis function network made it possible to highlight effects that were not considered by previous analyses of the same data. Copyright © 2001 John Wiley & Sons, Ltd.
Estimation of bivariate measurements having different change points, with application to cognitive ageing
Authors: Hall Charles B. , Ying Jun , Kuo Lynn , Sliwinski Martin , Buschke Herman , Katz Mindy , Lipton Richard B. 
Published: August 2002

AbstractLongitudinal studies of ageing make repeated observations of multiple measurements on each subject. Change point models are often used to model longitudinal data. We demonstrate the use of Bayesian and profile likelihood methods to simultaneously estimate different change points in the longitudinal course of two different measurements of cognitive function in subjects in the Bronx Aging Study who developed Alzheimer's disease (AD). Analyses show that accelerated memory decline, as measured by Buschke Selective Reminding, begins between seven and eight years before diagnosis of AD, while decline in performance on speeded tasks as measured by WAIS Performance IQ begins slightly more than two years before diagnosis, significantly after the decline in memory. Copyright © 2001 John Wiley & Sons, Ltd.
Prediction of survival and opportunistic infections in HIV‐infected patients: a comparison of imputation methods of incomplete CD4 counts
Authors: Molenberghs Geert , Williams Paige L. , Lipsitz Stuart R. 
Published: August 2002

AbstractIn evaluating the risk of mortality or development of opportunistic infections in HIV‐infected patients, the number of CD4 lymphocyte cells per cubic millimetre of blood is widely recognized as one of the best available predictors of such future events. However, its usefulness is limited by the incompleteness and variability of such CD4 measurements during follow‐up. Because of these limitations, analysis of such data requires the missing measurements to be ‘filled in’ or the patients without them to be excluded. We consider multiple imputation of CD4 values based partly on information from other health status measures such as haemoglobin, as well as on the event status of interest. These alternative health status measures are also considered as possible independent predictors of survival endpoints. Our work is motivated by a cohort of 1530 patients enrolled in two AIDS clinical trials. We compare our approach to other strategies such as basing evaluation of risk on baseline CD4, the last measured CD4 before an event, or a time‐dependent covariate based on carrying the last CD4 value forward; we conclude with a strong recommendation for multiple imputation. Copyright © 2002 John Wiley & Sons, Ltd.
Sample size re‐estimation in cluster randomization trials
Authors: Lake Stephen , Kammann Erin , Klar Neil , Betensky Rebecca 
Published: August 2002

AbstractCluster randomization trials in which families are the unit of allocation are commonly adopted for the evaluation of disease prevention interventions. Sample size estimation for cluster randomization trials depends on parameters that quantify the variability within and between clusters and the variability in cluster size. Accurate advance estimates of these nuisance parameters may be difficult to obtain and misspecification may lead to an underpowered study. Since families are typically recruited over time, we propose using a portion of the data to estimate the nuisance parameters and to re‐estimate sample size based on the estimates. This extends the standard internal pilot study methods to the setting of cluster randomization trials. The effect of this design on the power, significance level and sample size is analysed via simulation and is shown to provide a flexible and practical approach to cluster randomization trials. Copyright © 2002 John Wiley & Sons, Ltd.
Construction of a single global scale for multi‐item assessments of the same variable
Authors: Svensson Elisabeth 
Published: August 2002

AbstractComplex health‐related concepts are commonly measured by means of multi‐item scales or questionnaires. As the item scales of an instrument cover different aspects of the same variable, a single global response value is required of the concept to be measured. In this paper, different approaches that take into account the non‐metric properties of ordered categorical data when aggregating multi‐item scales into global scaling were suggested. A single score of equally important items is easily defined by the median. When the multi‐items are constructed to identify the most serious sign of a particular state, the maximum categorical level of the items could be an appropriate single score of the variable. By means of the joint response scheme over two aspects of the same variable, a global scale with an optional number of ordered categories could be defined. Some of the multi‐item scales of the Short‐Form Health Survey (SF‐36) and Euro‐QoL were used for illustrations to the proposed approaches. Copyright © 2001 John Wiley & Sons, Ltd.
How should meta‐regression analyses be undertaken and interpreted?
Authors: Thompson Simon G. , Higgins Julian P. T. 
Published: August 2002

AbstractAppropriate methods for meta‐regression applied to a set of clinical trials, and the limitations and pitfalls in interpretation, are insufficiently recognized. Here we summarize recent research focusing on these issues, and consider three published examples of meta‐regression in the light of this work. One principal methodological issue is that meta‐regression should be weighted to take account of both within‐trial variances of treatment effects and the residual between‐trial heterogeneity (that is, heterogeneity not explained by the covariates in the regression). This corresponds to random effects meta‐regression. The associations derived from meta‐regressions are observational, and have a weaker interpretation than the causal relationships derived from randomized comparisons. This applies particularly when averages of patient characteristics in each trial are used as covariates in the regression. Data dredging is the main pitfall in reaching reliable conclusions from meta‐regression. It can only be avoided by prespecification of covariates that will be investigated as potential sources of heterogeneity. However, in practice this is not always easy to achieve. The examples considered in this paper show the tension between the scientific rationale for using meta‐regression and the difficult interpretative problems to which such analyses are prone. Copyright © 2002 John Wiley & Sons, Ltd.
Designing linked micromap plots for states with many counties
Authors: Carr Daniel B. 
Published: August 2002

AbstractThis paper describes the design of linked micromap plots for showing county estimates on a state by state basis. The linked micromap template was specifically developed to represent spatially indexed statistical summaries. Each plot shows regional names, spatial patterns and statistical patterns while linking them all together. Thus the design is useful for communicating summaries from a host of health and environmental studies. The specific design challenge in this paper is to create one‐page plots for the states with 60 to 120 counties. While the county names and micromaps take up substantial space, the three examples demonstrate that there is sufficient space to represent two variables. The basic design has the potential for showing more. Consequently the new designs are suitable for presenting sophisticated summaries. Copyright © 2001 John Wiley & Sons, Ltd.