bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and implementation of the Solelc distributed operating system
Authors: Shiba Masahito , Okubo Eiji 
Published: September 2002

AbstractIn order to efficiently use multiple computers on a network, resource management that takes all those computers into account is desirable. However, the resources that each conventional operating system manages are limited to those of the computer on which it works. By making the operating system itself work in a location‐transparent fashion, it becomes possible to manage all resources on multiple computers with a single operating system. In this paper, we propose an abstraction method for location‐transparent management of computer resources such as memory, CPUs, interrupts, and peripheral devices. The structure and performance evaluations of the Solelc distributed operating system, which is based on this method, are described. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(10): 54–63, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10011
Design of a multiple‐operand redundant binary adder
Authors: Sakamoto Masahiro , Hamano Daisuke , Morisue Mititada 
Published: September 2002

AbstractThis paper describes a novel multiple‐operand redundant binary adder. The novel multiple‐operand addition algorithm can eliminate the carry propagation chain by dividing the input operands into an even place part and an odd place part, and adding them. The multiple‐operand adder with this algorithm can add six operands in parallel, and is faster than the ordinary tree‐structured method. A hardware model for the proposed adder implemented by the bidirectional current‐mode MOSFET circuit technology is described. Simulations have been made with HSPICE in order to verify the function of the proposed circuit. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(10): 1–9, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10182
An automatic video indexing method based on shot classification
Authors: Ide Ichiro , Yamamoto Koji , Hamada Reiko , Tanaka Hidehiko 
Published: September 2002

AbstractWith the recent increase in the number of news videos and in their value, their automatic indexing has been anticipated. Among various proposals for this problem, the use of textual data has been actively considered, and some applications of this type have actually been developed. Nonetheless, most of these approaches are textual data oriented, and a few of them consider the correspondences between their indexes (keywords) and image contents which are essentials for an image database.This paper proposes an automatic video indexing method which takes advantage of the characteristic of news videos: similar images have similar contents. The method tags indexes selectively according to typical image content. The method has been applied to actual news videos, and indexing has been successful for between 25% and 93% of “typical shots,” and for between 75% and 100% of “captionized shots.” © 2001 Scripta Technica, Syst Comp Jpn, 32(9): 32–41, 2001
Elliptic arc discrimination using conjugate diameter of chord
Authors: Mori Katsumi , Watanabe Eiji , Katagiri Shigekazu 
Published: September 2002

AbstractThere are many solids of revolution in our surroundings. Since they have elliptic outlines, discriminating elliptic arcs is an important technique for recognizing objects. The presence of diameters is a significant property of ellipses and has been effectively used in many methods of recognizing ellipses. However, the property is not valuable in discriminating short elliptic arcs because diameters are meaningless for short arcs. This paper proposes a method of discriminating elliptic arcs using two parallel scanning lines to a conjugate diameter of a chord. The method requires accurate determination of the conjugate diameter. First, the procedure of binary searching for the conjugate diameter will be established. Next, the method is tested on a real image to prove its validity. Finally, tolerance to noise and sensitivity to deformations of the method will be evaluated. © 2001 Scripta Technica, Syst Comp Jpn, 32(13): 1–13, 2001
An interactive image retrieval system with self‐explanation function
Authors: Maeda Shigenori , Mukunoki Masayuki , Minoh Michihiko , Ikeda Katsuo 
Published: September 2002

AbstractIn an image retrieval system, accurately extracting the content of the image which users want to search for based on an image in their heads is vital. As a result, many attempts have been made to use an image similar to the sought‐for image as a retrieval key and thereby to increase the freedom of expression for users' images. Because of the high variability of image characteristics, however, the vagueness of the content which indicates the retrieval key itself rises compared to conventional methods that use keywords or other linguistic resources for the retrieval key. Therefore, in this research the authors consider these problems by reviewing image retrieval from the perspective of image communications between users and the system, and then propose an interactive mechanism which limits the increase in vagueness while using an image as the retrieval key. The authors then perform retrievals by having users revise the retrieval key based on this mechanism. The authors create their interactive mechanism in a real image retrieval system and confirm its validity through experiments. © 2001 Scripta Technica, Syst Comp Jpn, 32(13): 41–51, 2001
A method for analyzing a queuing network by the tagged‐task model
Authors: Imai Hiroei , Tsunoyama Masahiro , Ishii Ikuo , Makino Hideo 
Published: September 2002

AbstractThis paper considers faults in distributed real‐time systems modeled by queuing networks; in particular, a fast method of analysis of transient variation of system performance is proposed. This method involves analyzing queuing networks by means of the tagged‐task model. Such an analysis requires repetitive determination of the limit‐state probability at varied initial values; however, the computation time can be reduced by using the absorption probability (the probability of arriving at the absorption state). In addition, a fast algorithm is proposed to calculate absorption probability, in which the state set is split into cosets according to arrivability, and the cosets are replaced by representatives as soon as the state probability becomes low. Finally, the effectiveness and accuracy of the proposed method are verified by actual examples. © 2001 Scripta Technica, Syst Comp Jpn, 32(13): 52–60, 2001
Parallel image segmentation with adaptive mesh
Authors: Lee Sang‐Sun , Tanaka Hiromi T. 
Published: September 2002

AbstractWe propose a parallel segmentation algorithm for general images which does not require advance knowledge of the image and where no initial assumptions about the number and position of regions are needed. This algorithm splits the image into a set of small triangular regions with uniform image properties, and the hierarchical construction is based on a parallel adaptive mesh algorithm. Based on a recursive binary traversal of discontinuities of image properties, hierarchical binary split and merge processing is performed. In this paper, a region is defined as space of the image where the features have smooth variation. By evaluating the homogeneity of the region using local differential properties representing the smoothness of the image, the problems of the starting point of processing and of order dependence are solved. Matching between blocks is ensured by sharing the small overlapping space that is needed to preserve the continuity of local properties. Further, it is possible to extract a region boundary line that matches the discontinuities of the local properties. Experiments performed on artificial intensity images, color real images, and range real images confirmed the universality and effectiveness of the proposed algorithm. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(10): 95–104, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1161
Test sequence compaction methods for acyclic sequential circuits using a time expansion model
Authors: Hosokawa Toshinori , Inoue Tomoo , Hiraoka Toshihiro , Fujiwara Hideo 
Published: September 2002

AbstractTest sequences for acyclic sequential circuits can be generated by using a time expansion model. In this paper, static and dynamic test sequence compaction techniques are proposed in which the test sequence generated by the time expansion model has two characteristics: (1) The test sequence length is constant, and (2) The location of an undefined value (X) for all primary inputs can be determined independently of test generation faults. First, a static test sequence compaction method is proposed that uses a template which is independent of the value of the test sequence. Then a dynamic test sequence compaction method is presented using reverse transform fault simulation, performing fault simulation for the time expansion model of the test pattern in which the test sequence after compaction is reverse‐transformed. As a result of application of the proposed method to acyclic sequential circuits made by using partial scan design, the test sequence length was reduced by 19 to 34%. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(10): 105–115, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1162
Testing model fit in longitudinal data analysis against alternatives with omitted covariates
Authors: Wang Jin , Shao Jun , Palta Mari 
Published: September 2002

AbstractSeveral types of common model misspecifications can be re‐formulated as problems of omitted covariates. These include situations with unmeasured confounders, measurement errors in observed covariates and informative censoring. Longitudinal data present special opportunities for detecting omitted covariates that are related to the observed ones differently across time than across individuals. This situation arises with period and cohort effects, as well as with usual formulations of classical measurement error in observed covariates. In this article we focus on testing for the existence of omitted covariates in longitudinal data analysis when models are fit by generalized estimation equations. When omitted covariates are present, specification of the correct link function conditionally on only observed covariates under the alternative usually involves complicated numerical integration. We propose a quasi‐score test statistic that avoids the need to fit such alternative models. The statistic is asymptotically chi‐square distributed under the null hypothesis of no omitted covariates with degrees of freedom determined by the assumed alternative structure. We study the significance level and the power of the quasi‐score test in linear and logistic regression models. The test is then applied to an analysis of excessive daytime sleepiness. Copyright © 2002 John Wiley & Sons, Ltd.
Individual bioequivalence testing under 2×3 designs
Authors: Chow Shein‐Chung , Shao Jun , Wang Hansheng 
Published: September 2002

AbstractIn recent years, as more generic drug products become available, it is a concern not only whether generic drug products that have been approved based on the regulation of average bioequivalence will have the same quality, safety and efficacy as that of the brand‐name drug product, but also whether the approved generic drug products can be used interchangeably. In its recent draft guidance, the U.S. Food and Drug Administration (FDA) recommends that individual bioequivalence (IBE) be assessed using the method proposed by Hyslop, Hsuan, and Holder to address drug switchability. The FDA suggests that a 2×4 cross‐over design be considered for assessment of IBE, while a 2×3 cross‐over design may be used as an alternative design to reduce the length and cost of the study. Little or no information regarding the statistical procedures under 2×3 cross‐over designs is discussed in the guidance. In this paper, a detailed statistical procedure for assessment of IBE under 2×3 cross‐over designs is derived. The main purpose of this paper, however, is to derive an IBE test under an alternative 2×3 design and show that the resulting IBE test is better than that under a 2×3 cross‐over design and is comparable to or even better than that under a 2×4 cross‐over design. Our conclusions are supported by theoretical considerations and empirical results. Furthermore, a method of determining the sample sizes required for IBE tests to reach a given level of power is proposed. Copyright © 2002 John Wiley & Sons, Ltd.
Meta‐analysis of method comparison studies
Authors: Williamson P. R. , Lancaster G. A. , Craig J. V. , Smyth R. L. 
Published: September 2002

AbstractMethods for the meta‐analysis of results from randomized controlled trials are well established. However, there are currently no methods for the meta‐analysis of method comparison studies. Here the combination of results from studies comparing two methods of measurement on the same unit of observation is required. We compare standard methods for the pooling of k samples from the same Normal population to those for pooling parameter estimates, in order to estimate the pooled mean difference and 95 per cent limits of agreement. Methods for investigating heterogeneity across studies and for calculating random effects estimates are proposed. We postulate that for published studies either the estimated mean or variance of the difference between measurements will tend to be smaller than for unpublished studies and investigate the evidence for the existence of such publication bias. The methods are illustrated with an example evaluating the accuracy of temperature measured at the axilla compared to the rectum in children. Copyright © 2002 John Wiley & Sons, Ltd.
Bayesian two‐stage designs for phase II clinical trials
Authors: Tan Say‐Beng , Machin David 
Published: September 2002

AbstractMany different statistical designs have been used in phase II clinical trials. The majority of these are based on frequentist statistical approaches. Bayesian methods provide a good alternative to frequentist approaches as they allow for the incorporation of relevant prior information and the presentation of the trial results in a manner which, some feel, is more intuitive and helpful. In this paper, we propose two new Bayesian designs for phase II clinical trials. These designs have been developed specifically to make them as user friendly and as familiar as possible to those who have had experience working with two‐stage frequentist phase II designs. Thus, unlike many of the Bayesian designs already proposed in the literature, our designs do not require a distribution for the response rate of the currently used drug or the explicit specification of utility or loss functions. We study the properties of our designs and compare them with the Simon two‐stage optimal and minimax designs. We also apply them to an example of two recently concluded phase II trials conducted at the National Cancer Centre in Singapore. Sample size tables for the designs are given. Copyright © 2002 John Wiley & Sons, Ltd.
Designing complex group sequential survival trials
Authors: Lakatos Edward 
Published: September 2002

AbstractThis paper presents methodology for designing complex group sequential survival trials when the survival curves will be compared using the logrank statistic. The method can be applied to any treatment and control survival curves as long as each hazard function can be approximated by a piecewise linear function. The approach allows arbitrary accrual patterns and permits adjustment for varying rates of non‐compliance, drop‐in and loss to follow‐up. The calendar‐time–information‐time transformation is derived under these complex assumptions. This permits the exploration of the operating characteristics of various interim analysis plans, including sample size and power. By using the calendar‐time–information‐time transformation, information fractions corresponding to desired calendar times can be determined. In this way, the interim analyses can be scheduled in information time, assuring the desired power and realization of the spending function, while the interim analyses will take place according to the desired calendar schedule. Copyright © 2002 John Wiley & Sons, Ltd.
Methods for estimating the AIDS incubation time distribution when date of seroconversion is censored
Authors: Geskus Ronald B. 
Published: September 2002

AbstractIn most cohort studies on HIV infection and AIDS, data on time from seroconversion to AIDS or death are doubly censored, both at the time origin and at the endpoint of interest. In epidemiological research, the most frequently adopted approach is to restrict the analysis to persons with narrow seroconversion intervals and to impute the midpoint of this interval as date of seroconversion. For many cohort studies, the consequence is that a substantial proportion of the data is not used. We consider four methods that are expected to be less biased when all cohort data are used: two imputation methods, conditional mean and multiple imputation, and two likelihood maximization methods. We derive the likelihood structure of the cohort data and clarify its dependence on study design. All methods are applied to data from the Amsterdam cohort study among injection drug users. In a simulation study the data generation process of this cohort study is imitated. The performance of midpoint, conditional mean and multiple imputation are compared. With midpoint imputation, both an analysis using the full data set, as well as one restricted to the cases with small seroconversion intervals, is performed. Conditional mean imputation comes out as the preferred method. It gives best results with respect to mean squared error. Moreover, when confidence intervals are computed through standard methods that ignore the uncertainty in the imputed date of seroconversion, coverage probabilities are almost correct. Copyright © 2001 John Wiley & Sons, Ltd.
Bayesian analyses of longitudinal binary data using Markov regression models of unknown order
Authors: Erkanli Alaattin , Soyer Refik , Angold Adrian 
Published: September 2002

AbstractWe present non‐homogenous Markov regression models of unknown order as a means to assess the duration of autoregressive dependence in longitudinal binary data. We describe a subject's transition probability evolving over time using logistic regression models for his or her past outcomes and covariates. When the initial values of the binary process are unknown, they are treated as latent variables. The unknown initial values, model parameters, and the order of transitions are then estimated using a Bayesian variable selection approach, via Gibbs sampling. As a comparison with our approach, we also implement the deviance information criterion (DIC) for the determination of the order of transitions. An example addresses the progression of substance use in a community sample ofn=242 American Indian children who were interviewed annually four times. An extension of the Markov model to account for subject‐to‐subject heterogeneity is also discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Notes on interval estimation of the attributable risk in cross‐sectional sampling
Authors: Lui Kung‐Jong 
Published: September 2002

AbstractThe attributable risk (AR) is probably the most useful and commonly used epidemiologic index to measure the importance of a risk factor in public health issues. This paper focuses the discussion on interval estimation of the AR in cross‐sectional studies and compares the finite‐sample performance of five asymptotic interval estimators of the AR by calculating the coverage probability and the average length in a variety of situations. This paper notes that the coverage probability of the two interval estimators proposed by Leung and Kupper, including the one that combines the interval estimator on the basis of Wald's test statistic, can be substantially less than the desired confidence level when the underlying risk ratio equals 1. As long as the sample size is reasonably large (⩾100) and the probability of exposure is moderate (⩾0.20), the interval estimator suggested by Fleiss can consistently perform well with respect to the coverage probability in a variety of situations considered here. However, using this interval estimator tends to generally lose efficiency. This paper also finds that with respect to the coverage probability, the interval estimator using Fieller's theorem is generally preferable to the interval estimator on the basis of Wald's test statistic when the prevalence rate ratio (RR) between the exposure and the non‐exposure groups is ⩾2. Finally, this paper notes that if we know that the underlying parameter RR is large (⩾4) and the probability of exposure is not small (⩾0.05), the interval estimator suggested by Leung and Kupper will probably be preferable to all the other estimators considered here. Copyright © 2001 John Wiley & Sons, Ltd.
Testing for the presence of cured patients: a simulation study
Authors: Peng Yingwei , Dear Keith B. G. , Carriere K. C. 
Published: September 2002

AbstractAn important but difficult problem in clinical trials is to determine the presence of cured patients when long‐term survivors are observed. The likelihood ratio test has been studied for this purpose in the gamma mixture model. However, its asymptotic null distribution is not readily available due to a violation of boundary conditions in the standard asymptotic theory. In this paper, a simulation study is employed to examine a proposed asymptotic null distribution of the likelihood ratio test. We find that the distribution can also be used to approximate the asymptotic null distribution of the likelihood ratio test in the Weibull and log‐normal mixture models when the censoring rate is not too light. However, the simulation study also shows that null distribution of the likelihood ratio test deviates significantly from the suggested distribution under moderate sample sizes when the censoring rate is small or the hazard rate is large. Consequently caution is needed in this case to determine the presence of cured patients. Finally, the results are used to confirm the presence of cured patients in a leukaemia study. Copyright © 2001 John Wiley & Sons, Ltd.
Modelling bivariate ordinal responses smoothly with examples from ophthalmology and genetics
Authors: Bustami Rami , Lesaffre Emmanuel , Molenberghs Geert , Loos Ruth , Danckaerts Marina , Vlietinck Robert 
Published: September 2002

AbstractA non‐parametric implementation of the bivariate Dale model (BDM) is presented as an extension of the generalized additive model (GAM) of Hastie and Tibshirani. The original BDM is an example of a bivariate generalized linear model. In this paper smoothing is introduced on the marginal as well as on the association level. Our non‐parametric procedure can be used as a diagnostic tool for identifying parametric transformations of the covariates in the linear BDM, hence it also provides a kind of goodness‐of‐fit test for a bivariate generalized linear model. Cubic smoothing spline functions for the covariates are estimated by maximizing a penalized version of the log‐likelihood. The method is applied to two studies. The first study is the classical Wisconsin Epidemiologic Study of Diabetic Retinopathy. The second study is a twin study, where the association between the elements of twin pairs is of primary interest. The results show that smoothing on the association level can give a significant improvement to the model fit. Copyright © 2001 John Wiley & Sons, Ltd.