bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sample size calculations for comparative studies of medical tests for detecting presence of disease
Authors: Alonzo Todd A. , Pepe Margaret S. , Moskowitz Chaya S. 
Published: January 2005

AbstractTechnologic advances give rise to new tests for detecting disease in many fields, including cancer and sexually transmitted disease. Before a new disease screening test is approved for public use, its accuracy should be shown to be better than or at least not inferior to an existing test. Standards do not yet exist for designing and analysing studies to address this issue. Established principles for the design of therapeutic studies can be adapted for studies of screening tests. In particular, drawing upon methods for superiority and non‐inferiority studies of therapeutic agents, we propose that confidence intervals for the relative accuracy of dichotomous tests drive the design of comparative studies of disease screening tests. We derive sample size formulae for a variety of designs, including studies where patients undergo several tests and studies where patients receive only one of the tests under evaluation. Both cohort and case‐control study designs are considered. Modifications to the confidence intervals and sample size formulae are discussed to accommodate studies where, because of the invasive nature of definitive testing, true disease status can only be obtained for subjects who are positive on one or more of the screening tests. The methods proposed are applied to a study comparing a modified pap test to the conventional pap for cervical cancer screening. The impact of error in the gold standard reference test on the design and evaluation of comparative screening test studies is also discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Regression‐based variable clustering for data reduction
Authors: McClelland R. L. , Kronmal R. A. 
Published: January 2005

AbstractIn many studies it is of interest to cluster states, counties or other small regions in order to obtain improved estimates of disease rates or other summary measures, and a more parsimonious representation of the country as a whole. This may be the case if there are too many to summarize concisely, and/or many regions with a small number of cases. By merging the regions into larger geographic areas, we obtain more cases within each area (and hence lower standard errors for parameter estimates), as well as fewer areas to summarize in terms of disease rates. The resulting clusters should be such that regions within the same cluster are similar in terms of their disease rates. In this paper we present a clustering algorithm which uses data at the subject‐specific level in order to cluster the original regions into a reduced set of larger areas. The proposed clustering algorithm expresses the clustering goals in terms of a regression framework. This formulation of the problem allows the regions to be clustered in terms of their association with the response, and confounding variables measured at the subject‐specific level may be easily incorporated during the clustering process. Additionally, this framework allows estimation and testing of the association between the areas and the response. The statistical properties and performance of the algorithm were evaluated via simulation studies, and the results are promising. Additional simulations illustrate the importance of controlling for confounding variables during the clustering process, rather than after the clusters are determined. The algorithm is illustrated with data from the Cardiovascular Health Study. Although developed with a specific application in mind, the method is applicable to a wide range of problems. Copyright © 2002 John Wiley & Sons, Ltd.
Analytic methods for comparing two dichotomous screening or diagnostic tests applied to two populations of differing disease prevalence when individuals negative on both tests are unverified
Authors: Berry Geoffrey , Smith Catherine L. , Macaskill Petra , Irwig Les 
Published: January 2005

AbstractTwo dichotomous screening tests may be compared by applying both tests to all members of a sampled population. For individuals with a positive result on either test the disease status may be verified by a reference standard, but for individuals negative on both tests the disease status may be unverified because the probability of disease is so low that further investigation is costly, unacceptable and perhaps unethical. If the tests have been applied to samples from two populations which have different disease prevalences then unbiased estimates of the true positive and false positive rates of each test, the prevalences in the two populations, and two parameters representing dependence between the two tests can be estimated using maximum likelihood methods. The methods are based on the assumption that the sensitivities and specificities of the two tests, and the dependencies between the tests, are independent of prevalence. A test of goodness of fit provides a test of this. Copyright © 2002 John Wiley & Sons, Ltd.
Comparing results of large clinical trials to those of meta‐analyses
Authors: Moses Lincoln E. , Mosteller Frederick , Buehler John H. 
Published: January 2005

AbstractWe consider methods for assessing agreement or disagreement between the results of a meta‐analysis of small studies addressing a clinical question and the result of a large clinical trial (LCT) addressing the same clinical question. We recommend basing conclusions about agreement upon the difference between the two results (relative risk, log‐odds ratio or similar summary statistic), in the light of the estimated standard error of that difference. To estimate the standard error of the meta‐analytic result we recommend a random effects analysis, and where a between‐studies variance component is found, that component of variance should be used twice: once in the estimated standard error for the meta‐analytic result and again in the standard error of the LCT result (augmenting the internal standard error of that statistic). Such broadening of the standard error reduces the appearance of disagreement. We also offer a critique of a different published approach, which is based on consistency of findings of statistical significance, a matter of how the two results regard zero, which is a poor measure of how closely they agree with each other. Copyright © 2002 John Wiley & Sons, Ltd.
Followers' entry timing: evidence from the Spanish banking sector after deregulation
Authors: Fuentelsaz Lucio , Gomez Jaime , Polo Yolanda 
Published: January 2005

AbstractMuch of the literature dedicated to the analysis of entry timing decisions has been devoted to the study of their consequences in terms of performance. However, only a limited amount of effort has been dedicated to analyzing the factors that determine these decisions. In addition, previous papers have centered their efforts on the product dimension, paying no attention to entry into new geographical markets. This paper departs from previous works in this respect and extends the entry timing literature through a consideration of the geographical side of entry. Our analysis shows that organizational size, organizational competence, and organizational experience appear as key factors when explaining the pattern of geographic diversification. Our results also indicate that diversification takes place sequentially, first proceeding to closer locations, then occupying markets further from the origin. Copyright © 2002 John Wiley & Sons, Ltd.
The communication turn in the theory of social systems
Authors: Leydesdorff Loet 
Published: January 2005

AbstractThe theory of social systems has been contested as a part of sociology. Social order can be expected to emerge as an expectation that is communicated. A communication can be provided with meaning and meaning may evolve into codified meaning. The social system can thus be considered as developing in layers of communication among reflexive actors. At the interfaces between systems theory, communication theory and evolution theory puzzles emerge which can also be formulated as analytical and empirical questions. The mathematical theory of communication can be used for the clarification of the relations among these different perspectives, since a message is expected to contain information. Copyright © 2002 John Wiley & Sons, Ltd.
Ambition and ambivalence, or: is there any system in andragology?
Authors: Notten Ton 
Published: January 2005

AbstractAndragogy and andragology do have something in common. It concerns something systems researchers have tried to deal with as well. Usually, in systems theory the ‘systemic’ aspect is equated, exclusively, with the functional aspects of human action, its ambitions and ambivalence, and the related justifications. According to that view, social (or moral) expressive ambitions are viewed as not being systematic and well organized, and are consequently identified as ‘life‐world related’. This option, however, might be disastrous for scientific progress in andragology. What seems most characteristic is that andragologists at least have learnt to consider this ‘life‐world’ as constitutive also and worthy of scientific study. They actually succeeded in finding a fertile holon, one that allows for the consideration of value descriptions in scientific exploration, thus integrating andragogy and andragology. This even appears to be a distinguishing contribution, brought forth by all those who ‘found themselves together’ in this old and new, strange and familiar area. They did not succumb to the present‐day seductive confusion between what is part of life and of experience (andragogy), and what is part of reflection and resistance to the evils of the day, with sufficient strength (andragology). The former aims to contribute functional, moral and expressive insights as supports to basic daily life; the latter to provide stability and authority against any fundamental, moral and expressive imposition, or colonization beyond such supports. Andragologists research functional, moral and expressive improvement, with the help of and adding to the andragogue's functional, moral and expressive insights. Copyright © 2002 John Wiley & Sons, Ltd.
A rigorous method for test templates generation from object‐oriented specifications
Authors: Periyasamy K. , Alagar V. S. 
Published: January 2005

AbstractThis paper describes a rigorous method that investigates the suitability of formal specifications written in Object‐Z specification language for testing object‐oriented software implementation in a black‐box fashion. The insight gained in the formalization of a model, the inherent abstractions, and formally specified intended behaviours and exceptions lead to the generation of test templates that are free from any implementation bias. The method described in this paper is an extension of the one proposed by Stocks and Carrington. In particular, the focus of the paper is on generating test templates for composite operations in an Object‐Z specification. The method is illustrated using the specification for an electronic mail system. The specification and the test templates generated for the electronic mail system show several interesting properties of the application that require considerable attention during testing. Copyright © 2001 John Wiley & Sons, Ltd.
Investigating the effectiveness of object‐oriented testing strategies using the mutation method
Authors: Kim Sun‐Woo , Clark John A. , McDermid John A. 
Published: January 2005

AbstractThe mutation method assesses test quality by examining the ability of a test set to distinguish syntactic deviations representing specific types of faults from the program under test. This paper describes an empirical study performed to evaluate the effectiveness of object‐oriented (OO) test strategies using the mutation method. The test sets for the experimental system are generated according to three selected OO test strategies and their effectiveness is compared by determining how well the developed test sets kill injected mutants derived from an established mutation system Mothra and the authors' own OO‐specific mutation technique which is termed Class Mutation. Copyright © 2001 John Wiley & Sons, Ltd.
Prediction of shear‐lag effects in framed‐tube structures with internal tube(s)
Authors: Lee Kang‐Kun , Lee Li‐Hyung , Lee Eun‐Jin 
Published: January 2005

AbstractThe shear‐lag phenomenon is a critical consideration in high‐rise building analysis and design. The shear‐lag behaviour of framed‐tube (including tube, tube‐in‐tube and tubes‐in‐tube constructions) is investigated for the behavioural characteristics of the structures and their performance in relation to the various structural parameters. The stiffness factor in terms of the axial stiffness of the columns and the bending stiffness of columns and beams is chosen as a main parameter to explain the shear‐lag phenomenon and the global behaviour of the structures. A simple numerical technique is also proposed for estimating the shear‐lag behaviour of framed‐tube systems with and without multiple internal tubes. Further work is carried out to demonstrate the simplicity and accuracy of the proposed method through the analysis of three framed‐tube structures (of different heights) without internal tubes and three other framed‐tube structures with single, two and three internal tubes. The shear‐lag phenomenon of such structures is studied taking into account the additional bending stresses in the tubes. Copyright © 2002 John Wiley & Sons, Ltd.
Simplified analysis of asymmetric high‐rise structures with cores
Authors: Hoenderkamp J. C. D. 
Published: January 2005

AbstractA simplified elastic hand‐method of analysis for asymmetric multi‐bent structures with cores subjected to horizontal loading is presented. The structures may consist of combinations of framed structures such as coupled walls, rigid frames and braced frames with planar and non‐planar shear walls. Results for structures that are uniform with height compare closely with results from stiffness matrix analyses. The method is developed from coupled‐wall deflection theory which is expressed in non‐dimensional structural parameters. It accounts for bending deformations in all individual members, axial deformations in the vertical members as well as torsion and warping in nonplanar walls. A closed solution of coupled differential equations for deflection and rotation gives the deflected shape along the height of the building from which all internal forces can be obtained. The proposed method of analysis offers a relatively simple and rapid means of comparing the deformations and internal forces of different stability systems for a proposed tall building in the preliminary stages of the design. The derivation of equations for analysis shown in this paper are for unisymmetric stability systems only, but the method is also applicable to general asymmetric structures with cores. Copyright © 2002 John Wiley & Sons, Ltd.
Optimum design of active/passive control devices for tall buildings under earthquake excitation
Authors: Xu Y.L. , Teng J. 
Published: January 2005

AbstractTo economically enhance the performance of active/passive control devices for seismic response reduction of tall buildings, this paper investigates the optimal placement and optimal parameter of control devices using the linear quadratic performance index as an objective function. The linear relation between the increment of performance index and the change of the position matrix of control devices is first established based on the assumption that the control gain remains unchanged. The optimal placement of control devices is then determined in terms of the sequence of the calculated performance index increments and the number of control devices to be used. With the control devices at their optimal places, the seismic response of the building is finally computed using the suboptimal control gain derived using the minimum error principle, from which the equivalent optimal parameters of passive devices can be also determined. The applicability of the proposed approach and its limitation are carefully examined through numerical examples. The results from the numerical examples show that the suggested approach is quite accurate and effective in determining the optimal placement and optimal parameter of control devices if the number of removed control devices is limited to a certain range. Copyright © 2002 John Wiley & Sons, Ltd.
Field measurements of amplitude‐dependent damping in a 79‐storey tall building and its efects on the structural dynamic responses
Authors: Li Q. S. , Yang K. , Zhang N. , Wong C. K. , Jeary A. P. 
Published: January 2005

AbstractThis paper describes some results obtained from full‐scale measurements of wind effects on a super‐tall building, Di‐Wang Tower, located in Shenzhen, China. This tall building has 79‐storeys with a height of approximately 324 m. Field measurements including wind speed, wind direction and wind‐induced acceleration responses have been made. The amplitude‐dependent characteristics of damping are obtained by using the random decrement technique from the detailed analysis of the field acceleration measurements. The main objective of this paper is to present detailed investigations into the effects of nonlinear damping on the dynamic responses of the tall building subjected to various types of applied loads based on the measured amplitude‐dependent damping characteristics. The predicted dynamic responses of the building obtained by using the measured damping characteristics were compared with those computed by using constant damping parameters assumed by the structural designers. It is concluded from the investigations that knowledge of actual damping characteristics are very important in the accurate prediction of the dynamic responses of a tall building when the major harmonic components of the applied loads overlap with the lowest natural frequencies of the building. The design damping level for tall building structures currently used by structural engineering practitioners appears to be high and not conservative. Copyright © 2002 John Wiley & Sons, Ltd.
Motion visualization of human left ventricle with a time‐varying deformable model for cardiac diagnosis
Authors: Choi Soo‐Mi , Kim Myoung‐Hee 
Published: January 2005

AbstractWe present a time‐varying deformable model to visualize and analyze the motion of the left ventricle from a time series of 3‐D images. The model is composed of a non‐rigid body that deforms around a reference shape obtained from the previous time step. At each time step, the position and orientation of the left ventricle are extracted from the feature points of images. This information gives the position and orientation of the coordinate system attached to the non‐rigid body. To compute a dense non‐rigid motion field over the entire endocardial wall of the left ventricle, we introduce a 3‐D blob finite element and Galerkin interpolants based on 3‐D Gaussian, and use a physically based finite element method and a modal analysis. Then, cinematic attributes are visualized in pseudo colors on the reconstructed surface in order to help medical doctors in their interpretation of the data. Using the presented model, we estimate clinically useful quantitative parameters such as regional wall motion and ejection fraction. Experimental results are shown in a time series of X‐ray angiographic images. Copyright ©2001 John Wiley & Sons, Ltd.
Reproducing works of Calder
Authors: Lee Dongkyoo , Bae Hee‐Jung , Tae Kim Chang , Lee Dong‐Chun , Jung Dae‐Hyun , Lee Nam‐Kyung , Lee Kyoo‐Ho , Baek Nakhoon , Won Lee J. , Woo Ryu Kwan , Hahn James K. 
Published: January 2005

AbstractMany fine art pieces have been reproduced in digital form. The digital reproductions have been used to store and transmit the original work. In contrast, mobiles, or moving sculptures, such as those designed by Alexander Calder cannot be reproduced realistically by photographs and/or static images. The real characteristics of mobiles come from the motions generated by interactive external forces applied to their structures. Hence people could not fully enjoy them through static images or even static three‐dimensional models. We present a virtual mobile system where users can easily control the mobile and can feel the impressions that the artist originally intended to provide. Virtual winds are generated by blowing on a microphone which then exert external forces to the mobile. This microphone interface lets users control the mobile while they are watching it through a monitor. We introduce a linear time solution for the constraint dynamics and an improved impulse dynamics to speed up the simulation. Using these techniques, we achieve a real‐time simulation of the mobile on personal computers. The techniques presented can easily be extended to simulate other interactive dynamics systems. Copyright ©2001 John Wiley & Sons, Ltd.
Open issues on TCP for mobile computing
Authors: Tsaoussidis Vassilis , Matta Ibrahim 
Published: January 2005

AbstractWe discuss the design principles of TCP within the context of heterogeneous wired/wireless networks and mobile networking. We identify three shortcomings in TCP's behavior: (i) the protocol's error detection mechanism, which does not distinguish different types of errors and thus does not suffice for heterogeneous wired/wireless environments, (ii) the error recovery, which is not responsive to the distinctive characteristics of wireless networks such as transient or burst errors due to handoffs and fading channels, and (iii) the protocol strategy, which does not control the tradeoff between performance measures such as goodput and energy consumption, and often entails a wasteful effort of retransmission and energy expenditure. We discuss a solution‐framework based on selected research proposals and the associated evaluation criteria for the suggested modifications. We highlight an important angle that did not attract the required attention so far: the need for new performance metrics, appropriate for evaluating the impact of protocol strategies on battery‐powered devices. Copyright © 2001 John Wiley & Sons, Ltd.
An Internet‐style approach to wireless link errors
Authors: Eckhardt David A. , Steenkiste Peter 
Published: January 2005

AbstractWireless links differ from traditional ‘wired’ links in two ways that challenge the existing Internet. On wireless links packet loss or corruption due to transmission errors is not rare, which calls into question the standard Internet assumptions that transmission errors should be corrected by transport‐level protocols at end systems and that end‐to‐end packet loss typically indicates network congestion. Also, the severity and location‐ dependent nature of these errors calls into question the meaning of ‘fair’ scheduling, per‐flow quality of service, and even looser notions such as service level agreements, when applied to wireless links. An important question is whether the two unique problems posed by wireless links can be successfully addressed within the standard Internet architecture, as opposed to requiring new transport protocols designed specifically for wireless links or requiring wireless links to ‘fix up’ the operation of specific end‐to‐end protocols. We provide experimental evidence that a combination of protocol‐blind link‐level local error control, which lessens the damage, and error‐sensitive link scheduling, which ensures sensible outcomes in response to link capacity loss, provides a good operating environment while adhering to traditional Internet design practices. Copyright © 2001 John Wiley & Sons, Ltd.