bluuebunny/crossref_metadata_2025 huggingface dataset:
An empirical comparison of record linkage procedures
Authors: Gomatam Shanti , Carter Randy , Ariet Mario , Mitchell Glenn
Published: August 2002

We consider the problem of record linkage in the situation where we have only non‐unique identifiers, like names, sex, race etc., as common identifiers in databases to be linked. For such situations much work on probabilistic methods of record linkage can be found in the statistical literature. However, although many groups undoubtedly still use deterministic procedures, not much literature is available on deterministic strategies. Furthermore, there appears to exist almost no documentation on the comparison of results for the two strategies. In this work we compare a stepwise deterministic linkage strategy with a probabilistic strategy, as implemented in AUTOMATCH, for a situation in which the truth is known. The comparison was carried out on a linkage between medical records from the Regional Perinatal Intensive Care Centers database and educational records from the Florida Department of Education. Social security numbers, available in both databases, were used to decide the true status of each record pair after matching. Match rates and error rates for the two strategies are compared and a discussion of their similarities and differences, strengths and weaknesses is presented. Copyright © 2002 John Wiley & Sons, Ltd.
A comparison of statistical methods for meta‐analysis
Authors: Brockwell Sarah E. , Gordon Ian R.
Published: August 2002

Meta‐analysis may be used to estimate an overall effect across a number of similar studies. A number of statistical techniques are currently used to combine individual study results. The simplest of these is based on a fixed effects model, which assumes the true effect is the same for all studies. A random effects model, however, allows the true effect to vary across studies, with the mean true effect the parameter of interest. We consider three methods currently used for estimation within the framework of a random effects model, and illustrate them by applying each method to a collection of six studies on the effect of aspirin after myocardial infarction. These methods are compared using estimated coverage probabilities of confidence intervals for the overall effect. The techniques considered all generally have coverages below the nominal level, and in particular it is shown that the commonly used DerSimonian and Laird method does not adequately reflect the error associated with parameter estimation, especially when the number of studies is small. Copyright © 2001 John Wiley & Sons, Ltd.
Estimating the causal effects of smoking
Authors: Rubin Donald B.
Published: August 2002

An important application of statistics in recent years has been to address the causal effects of smoking. There is little doubt that there are health risks associated with smoking. However, more general issues concern the causal effects due to the alleged misconduct of the tobacco industry or due to programmes designed to curtail tobacco use. To address any such causal question, assumptions must be made. Although some of the issues are well known in the statistical and epidemiological literature, there does not appear to be a unified treatment that provides prescriptive guidance on the estimation of these causal effects with explication of the needed assumptions. A ‘conduct attributable fraction’ is derived, which allows for arbitrary changes in smoking and non‐smoking health care expenditure related factors in a counterfactual world without the alleged misconduct, and therefore generalizes the traditional ‘smoking attributable fraction’. The formulation presented here, although described for the problem of estimating excess health care expenditures due to the alleged misconduct of the tobacco industry, is more general. It can be applied to any outcome, such as mortality, morbidity, or income from excise taxes, as well as to any situation in which consequences due to alleged misconduct (for example, of two entities, such as the tobacco and the asbestos industries) or due to hypothetical programmes (for example, extra smoking reduction initiatives) are to be estimated. Copyright © 2001 John Wiley & Sons, Ltd.
A mixed effects model for the analysis of ordinal longitudinal pain data subject to informative drop‐out
Authors: Pulkstenis Erik , Ten Have Thomas R. , Landis J. Richard
Published: August 2002

We extend the model of Pulkstenis et al. that models binary longitudinal data, subject to informative drop‐out through remedication, to the ordinal response case. We present a selection model shared‐parameter approach that specifies mixed models for both ordinal response and discrete survival time to remedication. In this fashion, the random parameter present in both models completely characterizes the relationship between response and time to remedication inducing their conditional independence. With a log‐log link function for both response and study ‘survival’, as well as specification of a log‐gamma distribution for the random effect, we obtain a closed‐form expression for the marginal log‐likelihood of response and time to remedication that does not require approximation or numerical integration techniques. A data analysis is performed and simulation results presented which support the consistency of parameter and standard error estimates. Copyright © 2001 John Wiley & Sons, Ltd.
A standardization method to adjust for the effect of patient selection in phase II clinical trials
Authors: Mazumdar Madhu , Fazzari Melissa , Panageas Katherine S.
Published: August 2002

New combination regimens evaluated in phase II cancer clinical trials often show promising results compared to the standard therapy for a disease system. Selection of patients with a better prognosis can be a prominent factor for this optimism. For most disease systems, prognostic variables that are related to the outcome are available and are called risk factors. Patients are classified into risk categories depending on the number of risk factors they possess. The patient distribution is defined as the proportion of patients falling into each of these risk categories. Typically, the patient distribution observed for a phase II study differs from the standard therapy reports so that the outcomes are not comparable. A randomized trial is the ultimate step for establishing the efficacy of a new treatment. In order to determine whether a regimen should progress to a phase III trial, we suggest adjusting the standard therapy outcome for the effect of the observed phase II patient distribution. If the endpoint of interest is tumour response proportion, a weighted average utilizing the standard therapy response proportions and the phase II patient distribution would provide an estimate of the adjusted standard therapy response proportion. Confirmatory phase II trials often attempt to estimate median survival in addition to response proportion, since this is the primary endpoint for most phase III cancer studies. Because data are censored, we propose an adjustment method based on the bootstrap resampling technique. We illustrate the problem of disparate patient selection with data from melanoma studies and demonstrate the usefulness of the proposed adjustment method with data from bladder cancer studies. A simulation study indicates that the magnitude of the adjustment is heavily dependent on the degree of separation of the risk categories. SAS code is available on a website (http://lib.stat.cmu.edu) for easy implementation. Copyright © 2001 John Wiley & Sons, Ltd.
Worm plot: a simple diagnostic device for modelling growth reference curves
Authors: Buuren Stef van , Fredriks Miranda
Published: August 2002

The worm plot visualizes differences between two distributions, conditional on the values of a covariate. Though the worm plot is a general diagnostic tool for the analysis of residuals, this paper focuses on an application in constructing growth reference curves, where the covariate of interest is age. The LMS model of Cole and Green is used to construct reference curves in the Fourth Dutch Growth Study 1997. If the model fits, the measurements in the reference sample follow a standard normal distribution on all ages after a suitably chosen Box–Cox transformation. The coefficients of this transformation are modelled as smooth age‐dependent parameter curves for the median, variation and skewness, respectively. The major modelling task is to choose the appropriate amount of smoothness of each parameter curve. The worm plot assesses the age‐conditional normality of the transformed data under a variety of LMS models. The fit of each parameter curve is closely related to particular features in the worm plot, namely its offset, slope and curvature. Application of the worm plot to the Dutch growth data resulted in satisfactory reference curves for a variety of anthropometric measures. It was found that the LMS method generally models the age‐conditional mean and skewness better than the age‐related deviation and kurtosis. Copyright © 2001 John Wiley & Sons, Ltd.
A methodology for analysing a repeated measures and survival outcome simultaneously
Authors: Rochon James , Gillespie Brenda W.
Published: August 2002

A considerable body of literature has arisen over the past 15 years for analysing univariate repeated measures data. It is rare in applied biomedical research, however, for interest to be restricted to a single outcome measure. In previous work, Rochon considered the case of bivariate repeated measures data in which each outcome is a discrete or continuous random variable. A GEE model was prescribed to relate each set of repeated measures to important explanatory variables. The ‘seemingly unrelated regression’ model was then applied to combine the pair of GEE models into an overall analysis framework. In this paper, we extend this approach to the case in which one endpoint is a repeated measures outcome but the second is a survival endpoint. Estimation and hypothesis testing issues are addressed and the methodology is illustrated with an example. Copyright © 2001 John Wiley & Sons, Ltd.
Comparisons of two‐part models with competitors
Authors: Lachenbruch Peter A.
Published: August 2002

Two‐part models arise when there is a clump of 0 observations in a distribution of continuous non‐negative responses. Several methods for comparing two such distributions are available. These include the straightforward application of the z‐test (or t‐test), the Wilcoxon–Mann–Whitney rank sum test, the Kolmogorov–Smirnov test, and three tests that use a 2 degree of freedom χ2 test based on the sum of the test for equality of proportions and a conditional χ2 test for the continuous responses. This conditional test may be the z‐test, the rank sum test, or the χ2 corresponding to the Kolmogorov–Smirnov test. This study compares the size and power of several of these methods. All tests have the appropriate distribution under the null hypothesis if the distribution of the continuous part has finite moments. If it does not, the z‐test has no power to detect any alternatives. It is found that the 2 d.f. tests are superior to the others when the larger proportion of 0 values corresponds to the population with the larger mean. If the reverse holds, the difference in the proportion of zeros reinforces the difference in means and some single‐part models (the rank sum or Kolmogorov–Smirnov) do best. In those cases, the two‐part models are not far behind, although statistically significantly poorer with respect to power. Published in 2001 by John Wiley & Sons, Ltd.
Nagelkerke N, Fidler V, Bernsen R, Borgdorff M, ‘Estimating treatment effects in randomized clinical trials in the presence of non‐compliance’, Statistics in Medicine 2000;19:1849–1864.
Authors: Nagelkerke Nico
Published: August 2002

The original article to which this Correction refers was published in Statistics in Medicine 2000; 19(14):1849–1864.
Estimating prevalence when the true disease status is incompletely ascertained
Authors: Sasieni Peter
Published: August 2002

We discuss the problem of estimating the number of cases not identified in studies of two or more screening tests in which not all individuals are fully evaluated. In particular we consider studies in which only those individuals who are positive on a screening test have a complete diagnosis. We show how to adjust for individuals who are not fully evaluated despite recommendation for referral and for cases not identified among those negative on all screening tests. The assumptions under which these adjustments are valid are discussed. A proposal is made for analysis of studies using three screening tests. Estimation of and inference about the disease prevalence and the test sensitivity when disease status is ascertained on a random sample of those negative on both screening tests is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
A weighted average likelihood ratio test for spatial clustering of disease
Authors: Gangnon Ronald E. , Clayton Murray K.
Published: August 2002

We consider methods proposed for detecting localized spatial clustering. We propose a new test statistic, the weighted average likelihood ratio test, as an alternative to the spatial scan (maximum likelihood ratio) test statistic. Two different types of weights are considered. We propose an unbiased cluster selection criterion and evaluate the bias of the tests through simulation. We also examine the power of the tests through simulations and apply the methods to the well‐known New York leukaemia data. Copyright © 2001 John Wiley & Sons, Ltd.
Meta‐analysis of ordinal outcomes using individual patient data
Authors: Whitehead Anne , Omar Rumana Z. , Higgins Julian P. T. , Savaluny Elly , Turner Rebecca M. , Thompson Simon G.
Published: August 2002

Meta‐analyses are being undertaken in an increasing diversity of diseases and conditions, some of which involve outcomes measured on an ordered categorical scale. We consider methodology for undertaking a meta‐analysis on individual patient data for an ordinal response. The approach is based on the proportional odds model, in which the treatment effect is represented by the log‐odds ratio. A general framework is proposed for fixed and random effect models. Tests of the validity of the various assumptions made in the meta‐analysis models, such as a global test of the assumption of proportional odds between treatments, are presented. The combination of studies with different definitions or numbers of response categories is discussed. The methods are illustrated on two data sets, in a classical framework using SAS and MLn and in a Bayesian framework using BUGS. The relative merits of the three software packages for such meta‐analyses are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Long‐term survivor mixture model with random effects: application to a multi‐centre clinical trial of carcinoma
Authors: Yau Kelvin K. W. , Ng Angus S. K.
Published: August 2002

A mixture model incorporating long‐term survivors has been adopted in the field of biostatistics where some individuals may never experience the failure event under study. The surviving fractions may be considered as cured. In most applications, the survival times are assumed to be independent. However, when the survival data are obtained from a multi‐centre clinical trial, it is conceived that the environmental conditions and facilities shared within clinic affects the proportion cured as well as the failure risk for the uncured individuals. It necessitates a long‐term survivor mixture model with random effects. In this paper, the long‐term survivor mixture model is extended for the analysis of multivariate failure time data using the generalized linear mixed model (GLMM) approach. The proposed model is applied to analyse a numerical data set from a multi‐centre clinical trial of carcinoma as an illustration. Some simulation experiments are performed to assess the applicability of the model based on the average biases of the estimates formed. Copyright © 2001 John Wiley & Sons, Ltd.
Sample size requirements for matched case‐control studies of gene–environment interaction
Authors: Gauderman W. James
Published: August 2002

Consideration of gene–environment (G×E) interaction is becoming increasingly important in the design of new epidemiologic studies. We present a method for computing required sample size or power to detect G×E interaction in the context of three specific designs: the standard matched case‐control; the case‐sibling, and the case‐parent designs. The method is based on computation of the expected value of the likelihood ratio test statistic, assuming that the data will be analysed using conditional logistic regression. Comparisons of required sample sizes indicate that the family‐based designs (case‐sibling and case‐parent) generally require fewer matched sets than the case‐control design to achieve the same power for detecting a G×E interaction. The case‐sibling design is most efficient when studying a dominant gene, while the case‐parent design is preferred for a recessive gene. Methods are also presented for computing sample size when matched sets are obtained from a stratified population, for example, when the population consists of multiple ethnic groups. A software program that implements the method is freely available, and may be downloaded from the website http://hydra.usc.edu/gxe. Copyright © 2002 John Wiley & Sons, Ltd.
A testing procedure for survival data with few responders
Authors: Freidlin Boris , Korn Edward L.
Published: August 2002

In the course of designing a clinical trial, investigators are often faced with the possibility that only a fraction of the patients will benefit from the experimental treatment. A proper clinical trial design requires prospective specification of the testing procedures to be used in the analysis. In the absence of reliable prognostic factors capable of identifying the appropriate subset of patients, there is a need for a test procedure that will be sensitive to a range of possible fractions of responders. Focusing on survival data, we propose guidelines for selecting a proper test procedure based on the anticipated proportion of responding patients. These guidelines suggest that the logrank test should be used when the fraction of responders is expected to be greater than 0.5, otherwise procedures based on weighted linear rank tests are preferable. Overall this approach provides good power properties when the treatment affects only a small proportion of patients while protecting against substantial loss of power when all patients are affected. Use of the procedure is illustrated with data from two published randomized studies. Published in 2002 by John Wiley & Sons, Ltd.
Repeated measures models for prescribing change
Authors: Sithole Jabulani S. , Jones Peter W.
Published: August 2002

Linear mixed models are used to detect a change, if any, in prescribing habits at the primary care practice level due to an educational intervention given repeated measures data before and after intervention and a control group.Inferences are corrected for general practice size, fundholding status and baseline prescribing. The correlation structure is discussed and the results for multilevel modelling using MLwiN and NLME version 3.0 are compared. Copyright © 2002 John Wiley & Sons, Ltd.
Stress prevention training: sex differences in types of stressors, coping, and training effects
Authors: Bekker Marrie H. J. , Nijssen Angelique , Hens Gonnie
Published: August 2002

The present study was aimed at examining the effectiveness of preventive group training and sex differences in types of work stressors, coping strategies, and training effects. Sixty‐eight trainees of stress prevention courses of Regional Institutions for Ambulatory Mental Health Care (RIAGGs) in the Netherlands took part in the study before training (T1), 36 of them after the training (T2), and 3 months later 24 of them (T3). For controlling time effects, a non‐training group was used as the control which had not sought help at a RIAGG nor suffered from stress complaints. Questionnaires were administered at all three time intervals, reflecting health, stress, coping, personality, and perceived job (context) characteristics. After training (T2), the trainees reported significantly less psychological and somatic complaints, less stress, a lower need for recovery after work, the use of more active coping and social support seeking, and a higher capability for managing new situations. The positive effects were maintained at T3. The control group showed no differences between T1 and T2. Women compared with men reported to have less executive tasks and possibilities in their jobs, and less participation and autonomy. Training effects were not affected by being male or female. However, before, as well as after training, women suffered from more health and stress complaints. Future training programmes might be improved by paying attention to sex differences in antecedents as well as consequences of work‐related stress. Copyright © 2001 John Wiley & Sons, Ltd.
Market microstructure in a global B2B network
Authors: Zaheer Srilata , Zaheer Akbar
Published: August 2002

On‐line marketplaces raise several interesting issues, among them the relevance of location when content is digitized, and the assessment of a supplier's capabilities when buyers worldwide only have electronic contact with sellers. In global B2B on‐line marketplaces, market microstructures, i.e. which firms compete for the same customers, are thus likely to be influenced by how customers value location and firm capabilities in their decisions to do business with different suppliers on‐line. We suggest that both these sets of attributes will continue to matter on‐line—firms possessing similar capabilities, as well as firms that are similar in location by country, time zones or clusters, will compete for business from the same customers. We model the similarity in competitive positions between pairs of firms based on the overlap in their customer networks, using data on actual interactions between supplier and customer banks on an electronic trading system. Using QAP network regression techniques on the 100 largest banks in this industry, we find that similarity in capabilities influences who competes with whom, and that location still matters in a global B2B exchange. Interestingly, location influences who a firm's competitors are, but not where its customers are from. Copyright © 2001 John Wiley & Sons, Ltd.
Organizational ownership, competitive intensity, and firm performance: an empirical study of the Indian manufacturing sector
Authors: Ramaswamy Kannan
Published: August 2002

Emerging countries are using privatization as a key strategy in their drive to become free market economies. Although these ownership changes are rapidly gaining prominence, the academic literature has been equivocal about the performance benefits of private vs. state ownership. The lack of clarity in findings can be largely traced to the underspecification of the models that prior studies have examined. Specifically, prior studies have mostly ignored the central role of competitive rivalry. This paper proposes a model that centers around the interactive, inseparable effects of ownership and competitive rivalry on firm performance. Results of the empirical examination set in India show that competitive intensity moderates the relationship between ownership and performance. Copyright © 2001 John Wiley & Sons, Ltd.
Real options in equity partnerships
Authors: Folta Timothy B. , Miller Kent D.
Published: August 2002

We examine factors influencing the decision to acquire additional equity in partner firms in research‐intensive industries. This decision involves choosing between flexibility and commitment. Option theory motivates hypotheses regarding the effects of uncertainty, valuation of developing technologies, and the threat of preemptive rivalry. Our main hypothesis is that the resolution of uncertainty for high‐value technologies motivates commitment decisions. We also argue that when the underlying growth option is at risk of preemption by rivals, greater uncertainty encourages commitment. An event history model tests these hypotheses using data from minority investments in the biotechnology industry. Copyright © 2002 John Wiley & Sons, Ltd.
Pay dispersion and workforce performance: moderating effects of incentives and interdependence
Authors: Shaw Jason D. , Gupta Nina , Delery John E.
Published: August 2002

The compensation literature is replete with arguments, but lacking in empirical tests, regarding the effects of pay dispersion on organizational outcomes. Pay dispersion may increase effort and provide incentives for high workforce performance levels, but may also inhibit cooperation and goal orientation among employees. Drawing on several theoretical perspectives (individual motivation, institutional theory, organizational justice, and neoclassical economics), this study predicts that pay dispersion will be associated with higher levels of workforce performance when accompanied by formal individual incentive systems and independent work, while pay compression is desirable in the absence of individual incentive systems and when work is interdependent. Survey research studies in two industrial sectors (the motor carrier and concrete pipe industries) were conducted to address these issues. Interactive regression results were generally supportive of the predictions across several measures of workforce performance (accident rates, safety violations, and productivity). Implications of these studies for strategy implementation in terms of compensation theory and practice are addressed. Copyright © 2002 John Wiley & Sons, Ltd.
Confined types in Java
Authors: Vitek Jan , Bokowski Boris
Published: August 2002

The sharing and transfer of references in object‐oriented languages is difficult to control. Without any constraint, practical experience has shown that even carefully engineered object‐oriented code can be brittle, and subtle security deficiencies can go unnoticed. In this paper, we present inexpensive syntactic constraints that strengthen encapsulation by imposing static restrictions on the spread of references. In particular, we introduceconfined typesto impose a static scoping discipline on dynamic references andanonymous methodsto loosen confinement somewhat to allow code reuse. We have implemented a verifier which performs a modular analysis of Java programs and provides a static guarantee that confinement is respected. Copyright © 2001 John Wiley & Sons, Ltd.
Partial redundancy elimination for access path expressions
Authors: Hosking Antony L. , Nystrom Nathaniel , Whitlock David , Cutts Quintin , Diwan Amer
Published: August 2002

Pointer traversals pose significant overhead to the execution of object‐oriented programs, since every access to an object's state requires a pointer dereference. Eliminating redundant pointer traversals reduces both instructions executed as well as redundant memory accesses to relieve pressure on the memory subsystem. We describe an approach to elimination of redundant access expressions that combines partial redundancy elimination (PRE) with type‐based alias analysis (TBAA). To explore the potential of this approach we have implemented an optimization framework for Java class files incorporating TBAA‐based PRE over pointer access expressions. The framework is implemented as a class‐file‐to‐class‐file transformer; optimized classes can then be run in any standard Java execution environment. Our experiments demonstrate improvements in the execution of optimized code for several Java benchmarks running in diverse execution environments: the standard interpreted JDK virtual machine, a virtual machine using ‘just‐in‐time’ compilation, and native binaries compiled off‐line (‘way‐ahead‐of‐time’). Overall, however, our experience is of mixed success with the optimizations, mainly because of the isolation between our optimizer and the underlying execution environments which prevents more effective cooperation between them. We isolate the impact of access path PRE using TBAA, and demonstrate that Java's requirement of precise exceptions can noticeably impact code‐motion optimizations like PRE. Copyright © 2001 John Wiley & Sons, Ltd.
The Relationlog system prototype
Authors: Liu Mengchi
Published: August 2002

The Relationlog system is a novel persistent deductive database system for advanced data and knowledge‐based applications. It directly supports the storage and inference of data with complex structures, especially data supported in nested relational and complex‐object models. The Relationlog system supports the Relationlog query language, which is a typed extension of Datalog with tuples and sets and stands in the same relationship to the nested relational and complex‐object models as Datalog stands to the relational model. It also supports an SQL‐like data definition language and a declarative data manipulation language. This article introduces the Relationlog language, discusses the system architecture, the design decisions incorporated within its implementation, and our experience in developing the system. Copyright © 2001 John Wiley & Sons, Ltd.
Design and implementation of efficient communication abstractions on the Virtual Interface Architecture: Stream sockets and RPC experience
Authors: Shah Hemal V. , Madukkarumukumana Rajesh S.
Published: August 2002

The emergence and standardization of system area networks (SANs) has provided distributed applications with a medium for high‐bandwidth, low‐latency communication. Standard user‐level networking architecture such as the Virtual Interface (VI) Architecture enables distributed applications to perform low overhead communication over SANs. The VI Architecture significantly reduces system processing overheads and provides each consumer process with a protected, directly accessible interface to the network hardware. Developing distributed applications using low‐level primitives provided by user‐level networking architecture like the VI Architecture is complex and requires significant effort.

This paper describes how high‐level communication paradigms like stream sockets and remote procedure call (RPC) can be efficiently built over the VI Architecture. To evaluate performance benefits for standard client–server and multi‐threaded environments, our focus is on off‐the‐shelf sockets and RPC interfaces and commercially available VI Architecture‐based SANs. The key design techniques developed in this paper include credit‐based flow control, decentralized user‐level protocol processing, caching of pinned communication buffers, and deferred processing of completed send operations.

In the experimental evaluation, the one‐way bandwidth achieved by stream sockets over VI Architecture was three to four times better than the bandwidth achieved by running legacy protocols over the same interconnect. On the same SAN, high‐performance stream sockets and RPC over VI Architecture achieve significantly better (between 2× and 3× less) latency than conventional stream sockets and RPC over standard networking protocols in a Windows NT™ 4.0 environment. Furthermore, our high‐performance RPC transparently improved the network performance of the distributed component object model (DCOM) by a factor of two to three. Copyright © 2001 John Wiley & Sons, Ltd.
Software testing using model programs
Authors: Manolache L. I. , Kourie D. G.
Published: August 2002

A strategy described as ‘testing using M model programs’ (abbreviated to ‘M‐mp testing’) is investigated as a practical alternative to software testing based on manual outcome prediction. A model program implements suitably selected parts of the functional specification of the software to be tested. The M‐mp testing strategy requires that M (M ≥ 1) model programs as well as the program under test, P, should be independently developed. P and the M model programs are then subjected to the same test data. Difference analysis is conducted on the outputs and appropriate corrective action is taken. P and the M model programs jointly constitute an approximate test oracle. Both M‐mp testing and manual outcome prediction are subject to the possibility of correlated failure. In general, the suitability of M‐mp testing in a given context will depend on whether building and maintaining model programs is likely to be more cost effective than manually pre‐calculating P's expected outcomes for given test data. In many contexts, M‐mp testing could also facilitate the attainment of higher test adequacy levels than would be possible with manual outcome prediction.

A rigorous experiment in an industrial context is described in which M‐mp testing (with M = 1) was used to test algorithmically complex scheduling software. In this case, M‐mp testing turned out to be significantly more cost effective than testing based on manual outcome prediction. Copyright © 2001 John Wiley & Sons, Ltd.
Semi‐automatic grammar recovery
Authors: Lämmel R. , Verhoef C.
Published: August 2002

We propose an approach to the construction of grammars forexistinglanguages. The main characteristic of the approach is that the grammars are not constructed from scratch but they are rather recovered by extracting them from language references, compilers and other artifacts. We provide a structured process to recover grammars including the adaptation of raw extracted grammars and the derivation of parsers. The process is applicable to possibly all existing languages for which business critical applications exist. We illustrate the approach with a non‐trivial case study. Using our process and some basic tools, we constructed in a few weeks a complete and correct VS COBOL II grammar specification for IBM mainframes. In addition, we constructed a parser for VS COBOL II, and were the first to publish a (Web‐enabled) grammar specification so that others can use this result to construct their own grammar‐based tools for VS COBOL II or derivatives. Copyright © 2001 John Wiley & Sons, Ltd.
Role of multimodal treatment in oropharynx, larynx, and hypopharynx cancer
Authors: Rudat Volker , Wannenmacher Michael
Published: August 2002

Due to recent advances in radiation fractionation, radiochemotherapy, and conservative surgical techniques, the concept of multimodal therapy in head and neck cancer is currently changing. The recently published RTOG Phase III trial 9003, with 1,113 patients accrued, showed that hyperfractionation and accelerated fractionation with concomitant boost are more efficacious than standard fractionation for locally‐advanced head and neck cancer. Acute, but not late, toxicity was also increased. Three meta‐analyses have suggested that the impact of chemotherapy in head and neck cancer is small but is highly associated with the timing of therapy. Concomitant administration of radiation therapy and chemotherapy led to an absolute benefit in 5‐year survival of about 10%. This finding has been further supported by recently published randomized prospective trials comparing concomitant radiochemotherapy with radiotherapy alone in advanced head and neck cancer. There is now clear evidence that radiochemotherapy provides a substantial and statistically significant improvement in survival and local‐regional control, as compared to radiotherapy alone. Radiochemotherapy should be considered an accepted standard of care in cancers of the oropharynx, particularly for patients with locally‐advanced disease who have a good performance status. Two randomized studies conducted by the Department of Veterans’ Affairs and the EORTC, with a total of 534 patients accrued, showed that induction chemotherapy followed by radiotherapy of responders yields survival rates equal to those of total laryngectomy with postoperative radiotherapy. After 4 years, one‐half to two‐thirds of survivors of the chemotherapy arm retained a functional larynx. Larynx preservation using induction chemotherapy can now be regarded as feasible but still investigational. Current phase II studies show excellent larynx preservation rates using a primary concomitant radiochemotherapy with an altered fractionation regimen. More clinical and laboratory research is required to further evaluate the different treatment options of the multimodality concept, and to develop prognostic models that will allow individualization of the therapy. Semin. Surg. Oncol. 20:66–74, 2001. © 2001 Wiley‐Liss, Inc.
Diagnostic and prognostic tumor markers in the gastrointestinal tract
Authors: Seregni Ettore , Ferrari Leonardo , Martinetti Antonia , Bombardieri Emilio
Published: August 2002

The gastrointestinal tract is the most common site of malignancies of any anatomic system in the body. An early detection of primary tumors of the bowel, pancreas, liver, stomach, and esophagus is often difficult in asymptomatic patients and for this reason these tumors are often detected at a relatively advanced stage, when symptoms lead to a diagnostic evaluation. Furthermore, gastrointestinal tract tumors have an extremely variable prognosis; thus, the identification of new prognostic parameters may be useful for selecting patients to more tailored therapies. In this work, the main molecular, genetic, tissular, and circulating tumor markers proposed for diagnosis and prognosis of gastrointestinal malignancies are reviewed and discussed. Semin. Surg. Oncol. 20:147–166, 2001. © 2001 Wiley‐Liss, Inc.
Minimal residual disease in non‐small‐cell lung cancer
Authors: Hosch Stefan B. , Scheunemann Peter , Izbicki Jakob R.
Published: August 2002

Early metastatic relapse after complete resection (R0) of apparently localized primary tumors is frequent in patients with non‐small‐cell lung cancer (NSCLC). This observation indicates an occult tumor cell dissemination already present at the time of primary surgery but undetectable by current tumor staging methods. During the past 10 years ultrasensitive immunohisto‐/‐cytochemical and molecular assays have been developed that are able to detect single tumor cells and small tumor cell clusters present in lymph nodes classified as tumor‐free by conventional histopathologic analysis, bone marrow, or peripheral blood. Here we present an overview of the incidence and prognostic impact of such early disseminated tumor cells in patients with NSCLC. Semin. Surg. Oncol. 20:278–281, 2001. © 2001 Wiley‐Liss, Inc.
Role of local excision in the treatment of rectal cancer
Authors: Rothenberger David A. , Garcia‐Aguilar Julio
Published: August 2002

Local excision (LE) of properly selected rectal cancers can provide long‐term survival, with minimal morbidity, negligible mortality, and excellent functional results. The role of LE has evolved over the past century. Initially, to avoid the excessive mortality of abdominal surgery, aggressive LE was performed to control the symptoms of rectal cancer. As abdominal surgery became safer, LE was restricted for use in palliation or high‐risk patients. Better preoperative tumor staging resulted in an expanded role for LE, including curative‐intent treatment of selected T1‐2 rectal cancers. Techniques for LE include snare polypectomy, transanal excision, transanal endoscopic microsurgery, and posterior approaches. The high local recurrence rate and compromised survival reported in modern series, despite efforts to properly select patients with cancers suitable for LE, have convinced the authors to restrict the use of curative‐intent LE in good‐risk patients only to the most favorable rectal cancers. Close follow‐up after LE is critical, because radical surgical salvage is usually possible if recurrence is identified promptly. Whether adjuvant chemoradiation can expand the role of curative intent LE remains controversial. Semin. Surg. Oncol. 19:367–375, 2000. © 2000 Wiley‐Liss, Inc.
Integration issues in implementation of structural control systems
Authors: Chu S. Y. , Soong T. T. , Reinhorn A. M. , Helgeson R. J. , Riley M. A.
Published: August 2002

Most of the recent research activities in structural control have been focused on developing more robust and rigorous control algorithms to account for more realistic dynamic environment. Although a number of active, hybrid and semi‐active control systems have been implemented to control the vibration of buildings, and many experimental studies have been conducted, the necessary knowledge needed for implementation is still not sufficient to prepare general guidelines for structural control system design and installation. Furthermore, the whole implementation process which requires integration of research results from diverse interdisciplinary areas has not been well addressed. The purpose of this paper is to introduce necessary knowledge needed to successfully implement general control system to a structure for safeguarding it against environmental forces such as wind or earthquakes. The major requirements of the analog/digital control hardware are first addressed. A custom‐designed signal interface unit equipped with conditioning, filtering, monitoring, fail‐safe limit detection, signal communication, and remote activation subsystems is then required to deal with the integrated system through the help of a digital computer. The implicit software issues between theoretical development and actual implementation, such as overall system configuration, sampling rates setup, analog‐I/O interface, hardware offsets removal, noise rejection, signal error modification, engineering units scaling, control algorithm implementation, system status monitoring, automatic operations of power and force generators, multi‐protection fail‐safe measures, false‐alarm control command rejection, and real‐time signal manipulation, should be included in a modular design of any control software for real implementational design. The important hardware and software safety and compatibility features have to be identified, verified and adjusted in order to eliminate many of the common problems that may occur in practical implementation of a complex control system. The idea of using a real‐time structural simulator (RTSS) to perform integrated system testing as well as control performance verification is also introduced. Copyright © 2002 John Wiley & Sons, Ltd.
Software agents in mobile telecommunication services
Authors: Bauer Bernhard , Müller Jörg
Published: August 2002

Agent technology has the potential to play a key role in building and supporting future telecommunication systems. In this article BERNHARD BAUER and JÖRG MÜLLER give an overview on the actual trends in telecommunication, namely on solutions, services, intelligent user interfaces, and networks and relate them to the current state in agent technology. Therefore, they first of all define the requirements that have to be satisfied to realize the potential created by actual technological innovations, next a closer look at the different kinds of software agents is given and afterwards their application and benefits in the above‐mentioned areas is shown. An assessment of agent technology in the area of telecommunication systems closes the considerations. Copyright © 2001 John Wiley & Sons, Ltd.
Activation of metabotropic glutamate receptors by repetitive stimulation in auditory cortex
Authors: Bandrowski A.E. , Moore S.L. , Ashe John H.
Published: August 2002

To determine whether metabotropic glutamate receptors (mGluRs) contribute to the responses of neurons to repetitive stimulation in the rat auditory cortex in vitro, five stimulus pulses were delivered at 2–100 Hz which elicited five depolarizing synaptic responses, f‐EPSPs: f‐EPSPs1–5. Stimulus pulses 2–5 delivered at low frequencies (2–10 Hz) elicited f‐EPSPs2–5 that were about 15% smaller than the response elicited by the first pulse (f‐EPSP1). In the presence of the nonspecific mGluR agonist, ACPD, the amplitude of all f‐EPSPs was 40% smaller than predrug responses. APV, CNQX, or bicuculline (antagonists of NMDA‐, AMPA/kainate‐, and GABAA‐receptors, respectively) did not change this effect of ACPD. The mGluR antagonist, MCPG, had no effect on f‐EPSPs but did reduce the effect of ACPD. High‐frequency stimulation (50–100 Hz) elicited f‐EPSPs that were smaller with each successive stimulus. In ACPD, f‐EPSP1 was 40% smaller than predrug, but f‐EPSPs3–5 were not changed compared to pre‐ACPD f‐EPSPs3–5, indicating that ACPD occludes the effect of repetitive stimulation. MCPG increased f‐EPSP5 by 15%, indicating that a portion of the reduction of f‐EPSPs during high‐frequency stimulation is mediated by mGluRs. MCPG also partially blocked the effect of ACPD. In CNQX, ACPD only decreased EPSPs, but APV or bicuculline did not change the effect of ACPD. These results suggest that the successive reduction of f‐EPSPs during a high‐frequency train is partially a result of mGluR activation. Synapse 44:146–157, 2002. © 2002 Wiley‐Liss, Inc.
Effect of tetrabenazine on the striatal uptake of exogenous L‐DOPA in vivo: A PET study in young and aged rhesus monkeys
Authors: DeJesus Onofre T. , Shelton Steven E. , Roberts Andrew D. , Nickles Robert J. , Holden James E.
Published: August 2002

The effect of tetrabenazine (TBZ) pretreatment on the striatal uptake of exogenous L‐DOPA in vivo was assessed noninvasively in rhesus monkeys by positron emission tomography (PET) using the tracer [18F]‐FluoroDOPA (FDOPA). Paired studies were done comparing baseline vs. TBZ treatment on the uptake of FDOPA, a measure of aromatic L‐amino acid decarboxylase (AAAD) activity. Results show increased AAAD activity with TBZ treatment. These results suggest that the action of TBZ as a dopamine antagonist dominates more than its expected action as a potent vesicular monoamine transporter (VMAT2) inhibitor. Results also showed diminished responsivity of AAAD to TBZ challenge in aged monkey brain. Synapse 44:246–251, 2002. © 2002 Wiley‐Liss, Inc.
System design is an NP‐complete problem
Authors: Chapman William L. , Rozenblit Jerzy , Bahill A. Terry
Published: August 2002

The system design process translates the customers' needs into a buildable system design. It requires selecting subsystems from an allowable set and matching the interfaces between them. Designs that meet the top‐level input and output requirements are tested to see how well they meet the system's performance and cost goals. This paper proves that the System Design Problem is NP‐complete by reduction from the Knapsack Problem, which is known to be NP‐complete. The implication of this proof is that designing optimal systems with deterministic, polynomial time procedures is not possible. This is the primary reason why engineers do not try to produce optimal systems: They merely produce designs that are good enough. © 2001 John Wiley & Sons, Inc. Syst Eng 4: 222–229, 2001
Inelastic analysis of steel frames with reduced beam sections
Authors: Kitjasateanphun T. , Shen J. , Srivanich W. , Hao H.
Published: August 2002

The present work addresses modelling issues in the inelastic analysis of steel frames with reduced beam sections (RBSs), and proposes two simple one‐dimensional structural models based on detailed three‐dimensional finite‐element analysis (FEA) and published testing behaviour of RBSs. The study begins with the FEA of a beam–column assembly with a reduced the beam section, which is compared with test results. More FEA models of RBS assemblies are generated with different configurations so that moment demand at column faces is in the range 80 to 100 per cent of the plastic moment capacity of the original beam section. The study extends to investigate the effect of panel zone when bilinear model is used in the simple structural model. The structural model of the RBS based on the combined FEA and test results captures the prevailing elastic and inelastic behaviour of the RBS assemblies, and correlates very well with the actual performance observed during testing. Copyright © 2001 John Wiley & Sons, Ltd.