bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distinctness of compositions of an integer: A probabilistic analysis
Authors: Hitczenko Paweł , Louchard Guy 
Published: August 2002

AbstractCompositions of integers are used as theoretical models for many applications. The degree of distinctness of a composition is a natural and important parameter. In this article, we use as measure of distinctness the number of distinct parts (or components). We investigate, from a probabilistic point of view, the first empty part, the maximum part size and the distribution of the number of distinct part sizes. We obtain asymptotically, for the classical composition of an integer, the moments and an expression for a continuous distributionF, the (discrete) distribution of the number of distinct part sizes being computable fromF. We next analyze another composition: the Carlitz one, where two successive parts are different. We use tools such as analytical depoissonization, Mellin transforms, Markov chain potential theory, limiting hitting times, singularity analysis and perturbation analysis. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 19: 407–437, 2001
The average‐case area of Heilbronn‐type triangles*
Authors: Jiang Tao , Li Ming , Vitányi Paul 
Published: August 2002

AbstractFrom among \documentclass{article}\pagestyle{empty}\begin{document}${n \choose 3}$\end{document} triangles with vertices chosen from n points in the unit square, let T be the one with the smallest area, and let A be the area of T. Heilbronn's triangle problem asks for the maximum value assumed by A over all choices of n points. We consider the average‐case: If the n points are chosen independently and at random (with a uniform distribution), then there exist positive constants c and C such that c/n3<μn<C/n3 for all large enough values of n, where μn is the expectation of A. Moreover, c/n3<A<C/n3, with probability close to one. Our proof uses the incompressibility method based on Kolmogorov complexity; it actually determines the area of the smallest triangle for an arrangement in “general position.” © 2002 Wiley Periodicals, Inc. Random Struct. Alg. 20: 206–219, 2002
Resource management model and performance evaluation for satellite communications
Authors: Jahn Axel 
Published: August 2002

AbstractEfficient resource management is mandatory to achieve maximum system capacity for next generation communications systems. Resource management deals with the available spectral band, time, power, and space for a transmission signal. It includes (i) the frequency planning, (ii) the selection of transmit power, and (iii) the assignment of the channels and access nodes to the users. The paper presents a generalized notation as well as graph algorithms for resource management problems. Impairment graphs can be used for frequency planning, whereas flow graphs are suitable for channel access problems. To evaluate the performance of the resource management, service criteria (such as blocking or the carrier to interference ratioC/I) or efficiency criteria (bandwidth requirements) can be derived from the graphs. The resource management techniques are applied to satellite networks with non‐geostationary orbits yielding time‐variant network topologies. As a simple example, the channel assignment and capacity optimization of the EuroSky Way system are shown. Furthermore, a comparison of fixed, dynamic and hybrid channel allocation schemes (FCA, DCA, HCA) for a typical MEO satellite scenario is given. Satellite diversity and its impact on bandwidth requirement and transmission quality is also examined. Finally, it is shown how spread spectrum systems can be investigated with the presented tools. Copyright © 2001 John Wiley & Sons, Ltd.
Supporting node mobility using mobile IPv6 in a LEO‐satellite network
Authors: Sarikaya Behcet , Tasaki Masaru 
Published: August 2002

AbstractThis paper investigates supporting IPv6, the next generation IP in a Teledesic‐like low earth orbit (LEO) satellite backbone. The network architecture consists of LEO satellites with intersatellite links, gateway stations, standard terminals and mobile terminals. This network offers mobile data services like earth cellular networks. Due to its enlarged addressing space, IPv6 is selected as the network layer. For routing IPv6 datagrams in this network, a tunnelling approach is taken in which IPv6 datagrams from/to the Internet are fragmented/reassembled into ATM‐cell‐like packets. To route these packets inside the LEO‐constellation, we design a unicast link‐state routing algorithm in which the responsibilities for routing are shared between the satellites and gateway stations. For user mobility, Mobile IPv6 extended for paging the users in standby mode is used. The paper concludes with a presentation of simulation results. Copyright © 2001 John Wiley & Sons, Ltd.
Science, culture, and the emergence of language
Authors: Roth Wolff‐Michael , Lawless Daniel 
Published: August 2002

AbstractA major achievement in the sociology and philosophy of science over the past two decades has been the recognition that science is a form of culture with its own creeds, language, material practices, perceptions, theories, and beliefs. Learning science then amounts to participation (from more peripheral to central ways) in the particular practices of this culture. We argue here that there are some fundamental, heretofore neglected, ways in which newcomers come to perceive and talk about natural phenomena. Beginning with “muddled” talk and supported by deictic and iconic gestures, learners isolate salient objects and events which are, in increasing ways, represented in linguistic forms. More abstract forms of communication (writing, abstract symbols) are competently used only later in the emerging communicative patterns. As such, there lies tremendous potential in science activities that focus on observational and theoretical language in the presence of the relevant phenomena. © 2002 Wiley Periodicals, Inc.Sci Ed86:368–385, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/sce.10008
On the substance of a sophisticated epistemology
Authors: Elby Andrew , Hammer David 
Published: August 2002

AbstractAmong researchers who study students' epistemologies, a consensus has emerged about what constitutes a sophisticated stance toward scientific knowledge. According to this community consensus, students should understand scientific knowledge as tentative and evolving, rather than certain and unchanging; subjectively tied to scientists' perspectives, rather than objectively inherent in nature; and individually or socially constructed, rather than discovered. Surveys, interview protocols, and other methods used to probe students' beliefs about scientific knowledge broadly reflect this outlook. This article questions the community consensus about epistemological sophistication. We do not suggest that scientific knowledge is objective and fixed; if forced to choose whether knowledge is certain or tentative, with no opportunity to elaborate, we would choose “tentative.” Instead, our critique consists of two lines of argument. First, the literature fails to distinguish between the correctness and productivity of an epistemological belief. For instance, elementary school students who believe that science is about discovering objective truths to questions, such as whether the earth is round or flat, or whether an asteroid led to the extinction of the dinosaurs, may be more likely to succeed in science than students who believe science is about telling stories that vary with one's perspective. Naïve realism, although incorrect (according to a broad consensus of philosophers and social scientists), may nonetheless be productive for helping those students learn. Second, according to the consensus view as reflected in commonly used surveys, epistemological sophistication consists of believing certain blanket generalizations about the nature of knowledge and learning, generalizations that do not attend to context. These generalizations are neither correct nor productive. For example, it would be unsophisticated for students to view as tentative the idea that the earth is round rather than flat. By contrast, they should take a more tentative stance toward theories of mass extinction. Nonetheless, many surveys and interview protocols tally students as sophisticated not for attending to these contextual nuances, but for subscribing broadly to the view that knowledge is tentative. © 2001 John Wiley & Sons, Inc. Sci Ed 85:554–567, 2001.
Toward inclusive science education: University scientists' views of students,instructional practices, and the nature of science
Authors: Bianchini Julie A. , Whitney David J. , Breton Therese D. , Hilton‐Brown Bryan A. 
Published: August 2002

AbstractThis study examined the perceptions and self‐reported practices of 18 scientists participating in a yearlong seminar series designed to explore issues of gender and ethnicity in science. Scientists and seminar were part of the Promoting Women and Scientific Literacy project, a curriculum transformation and professional development initiative undertaken by science, science education, and women's studies faculty at their university. Researchers treated participating scientists as critical friends able to bring clarity to and raise questions about conceptions of inclusion in science education. Through questionnaires and semistructured interviews, we explored their (a) rationales for differential student success in undergraduate science education; (b) self‐reports of ways they structure, teach, and assess courses to promote inclusion; and (c) views of androcentric and ethnocentric bias in science. Statistical analysis of questionnaires yielded few differences in scientists' views and reported practices by sex or across time. Qualitative analysis of interviews offered insight into how scientists can help address the problem of women and ethnic minorities in science education; constraints encountered in attempts to implement pedagogical and curricular innovations; and areas of consensus and debate across scientists and science studies scholars' descriptions of science. From our findings, we provided recommendations for other professional developers working with scientists to promote excellence and equity in undergraduate science education. © 2001 John Wiley & Sons, Inc.Sci Ed86:42–78, 2001.
Tagged communication and synchronization memory for multiprocessor‐on‐a‐chip
Authors: Iwane Masahiko , Yamawaki Akira , Tanaka Makoto 
Published: August 2002

AbstractMultiprocessor‐on‐a‐chip is becoming possible due to progress in semiconductor technologies. In the multiprocessor, the threaded parallel processing requires decreasing the overhead of interthread communication and synchronization. We propose the tagged communication and synchronization memory with the access counter using CAM (TCSM) which supports a high‐speed mechanism for the mutual exclusion, the condition synchronization, the barrier synchronization, and the multicasting between the threads. TCSM allocates its entries dynamically and ensures the producer–consumer synchronization by valid/invalid state in the access count. The execution environment of the threads is protected because the tag of TCSM is used for identifying both the task which threads belong to and the storage used by threads. The MTA/TCSM multichip multiprocessor system has been developed to evaluate the multiprocessor‐on‐a‐chip including TCSM. As a result of the evaluation on MTA/TCSM, the overhead of interthread synchronization and communication using TCSM is lower than using the conventional shared memory. © 2001 Scripta Technica, Syst Comp Jpn, 32(4): 1–13, 2001
Endoscope system for high‐speed 3D measurement
Authors: Hasegawa Kazuhide , Sato Yukio 
Published: August 2002

AbstractIn this paper, we will describe a technique for realizing high‐speed 3D measurement through an endoscope by combination of the space encoding method with laser scanning and the 3D endoscope. In this technique, the striped pattern of light based on the space encoding method is guided to the endoscope tip and made to illuminate the object by using one of the two image guide shafts embedded in the 3D endoscope. The pattern light image after irradiation is acquired from a color CCD camera installed at the other image guide shaft. This is repeated with the required number of frames of the space encoded patterns, and the calculation of the distance value is performed based on the principle of triangulation. In the proposed technique, the range image (512 × 242 pixels) can be acquired in 0.6 second. Moreover, since a color CCD camera is used, acquisition of the color information of the object surface can also be realized. Experiments show that the measurement error depends on the distance from the tip of the endoscope and is about 1% of the measuring distance in the range of 20 to 40 mm from the tip region. The practical possibility of the proposed technique is confirmed by performing shape reconstruction from the measurement results. © 2001 Scripta Technica, Syst Comp Jpn, 32(8): 30–39, 2001
The role of financial institutions in the sustainable development of Lebanon
Authors: Mezher Toufic , Jamali Dima , Zreik Carine 
Published: August 2002

AbstractAfter years of war, Lebanon is witnessing an era of reconstruction and development. Worldwide experience has proven, however, that development cannot and should not be accomplished at the expense of the environment and natural resources. Thus, guiding Lebanon towards a sustainable development path is a must. Lebanese financial institutions, which are a major player in the market, have the potential to accelerate the sustainable development of the country. This paper investigates the actual role played by Lebanese financial institutions in the quest for sustainable development and offers practical recommendations that should help this sector improve its performance regarding sustainability issues. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Cycles in the sky: understanding and managing business cycles in the airline market
Authors: Liehr Martin , Größler Andreas , Klein Martin , Milling Peter M. 
Published: August 2002

AbstractThe airline market is a highly cyclical business with relatively poor returns on invested capital. The fluctuations in the market put the carriers under severe economic pressure, and most of them lack strategies for cycle oriented behavior. The focus of the research conducted at Lufthansa German Airlines is the analysis of fundamental, cycle‐generating structures in the airline market and the identification of alternative strategies for effective “cycle‐management”. The system dynamics approach is combined with a statistical forecasting model—a combination that proved to be valuable for the analysis and management of airline business cycles. The article describes a successful system dynamics study in a complex and fast changing environment. Insights generated during the project work are now going to influence order policies for new commercial aircraft for the carrier. Copyright © 2001 John Wiley & Sons, Ltd.
Ellipsometric approach to the monitoring of tip–surface proximity in NFO
Authors: Bortchagovsky Eugene G. 
Published: August 2002

AbstractThis work continues the development of the proposed early ellipsometric approach to near‐field microscopy. It is devoted now to the demonstration of the possibility of monitoring the tip–surface distance at the tip's approach to a surface by analysis of the polarization state of scattered light. It is shown that such analysis distinguishes between different interferometric periods recorded at the approaching tip, so that it is possible to control the distance without restriction in one period. Such a method may be realized using a standard modern ellipsometer with a rotating analyser. Copyright © 2002 John Wiley & Sons, Ltd.
Combined STM, HREELS and ab initio study of the adsorption of uracil on Si(100)‐2 × 1
Authors: Lopez Alberto , Chen Qiao , Richardson Neville V. 
Published: August 2002

AbstractAdsorption of the nucleic acid base uracil on Si(100)‐2 × 1 has been studied using scanning tunnelling microscopy (STM), high‐resolution electron energy‐loss spectroscopy (HREELS) and ab initio calculations. The STM images show that uracil is able to form ordered structures on the surface on which the molecules adsorb preferentially along dimer rows. The HREEL spectra show a stronger intensity of the in‐plane modes compared with the out‐of‐plane vibrations. This indicates that the orientation of the molecular plane is more upright. The observation of a distinctive Si–H band in the vibrational spectra of Si(100)‐2 × 1 exposed to uracil indicates that adsorption of the molecule occurs through cleavage of an O–H/N–H bond. The vibrational spectra show that only the enol tautomer interacts with the surface, mainly through cleavage of the OH bond and the formation of an Si–O linkage. Copyright © 2002 John Wiley & Sons, Ltd.
Spatio‐temporal modelling of rates for the construction of disease maps
Authors: MacNab Ying C. , Dean C. B. 
Published: August 2002

AbstractThere have been significant developments in disease mapping in the past few decades. The continual development of statistical methodology in this area is responsible for the growing popularity of disease mapping because of its potential usefulness in regional health planning, disease surveillance and intervention, and allocating health funding. Here we review the area of disease mapping where relative risks pertain to an event such as incidence or mortality over space and time. In particular we briefly discuss the use of generalized additive mixed models, an additive extension of generalized linear mixed models, for spatio‐temporal analysis of disease rates. To illustrate the procedures, we present an in‐depth analysis of infant mortality data in the province of British Columbia, Canada. The goals of the analysis are to produce more reliable small‐area estimates of mortality rates, assess spatial patterns over time, and examine risk trends at both global (provincial) and local (local health area) levels. Copyright © 2002 John Wiley & Sons, Ltd.
A review of multilevel theory for ecologic analyses
Authors: Greenland Sander 
Published: August 2002

AbstractThis paper reviews multilevel and conventional models for the analysis of ecologic (group, aggregate) data. It emphasizes the non‐separability of contextual (group‐level) effects and individual‐level effects that arises from the multilevel structure of the underlying effects. Contrary to common misperceptions, this problem afflicts ecologic studies in which the sole objective is to estimate contextual effects, as well as studies in which the objective is to estimate individual effects. Multilevel effects also severely complicate causal interpretations of model coefficients. Copyright © 2002 John Wiley & Sons, Ltd.
A comparison of handsearching versus MEDLINE searching to identify reports of randomized controlled trials
Authors: Hopewell S. , Clarke M. , Lusher A. , Lefebvre C. , Westby M. 
Published: August 2002

AbstractThis study aims to compare handsearching to a basic MEDLINE search for the identification of reports of randomized trials in specialized health care journals. Twenty‐two specialized health care journals, published in the U.K., were handsearched for all reports of controlled trials (as defined by the Cochrane Collaboration). The reports of trials, which were judged to be definitely randomized, were identified from a random sample of three years per journal and form one element of this study. A MEDLINE search using the publication type terms ‘randomized controlled trial’ and ‘controlled clinical trial’ was also performed for the same journal years. The reports of trials retrieved by handsearching were then compared against those retrieved from the MEDLINE search, to identify differences in retrieval between the two techniques. Reports of randomized trials identified by the MEDLINE search but not found by handsearching were individually assessed to see if they met the Cochrane eligibility criteria for a report of a randomized trial. A total of 714 reports of randomized trials were found by using a combination of both handsearching and MEDLINE searching. Of these, 369 (52 per cent) were identified only by handsearching and 32 (4 per cent) were identified only by MEDLINE searching. Of the reports identified only by handsearching, 252 had no MEDLINE record, of which 232 (92 per cent) were meeting abstracts or published in supplements; 117 (25 per cent) of the 462 reports of randomized trials which had a MEDLINE record were missed by the electronic search because they did not have either of the publication type terms ‘randomized controlled trial’ or ‘controlled clinical trial’. This proportion varied depending on when the reports of randomized trials were published (that is, before or after the introduction of the MEDLINE publication type terms above). The highest additional yield from handsearching compared to MEDLINE searching was for reports of randomized trials published prior to 1991 and from handsearching the non‐MEDLINE indexed parts of a journal. The results of this study suggest that a combination of MEDLINE and handsearching is required to identify adequately reports of randomized trials. © Crown copyright 2002. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Projecting the standard error of the Kaplan–Meier estimator
Authors: Cantor Alan B. 
Published: August 2002

AbstractClinical studies in which a major objective is to produce Kaplan–Meier estimates of survival probabilities should be designed to produce those estimates with a desired prespecified precision as measured by their standard errors. By considering the Peto and Greenwood formulae for the estimated standard error of the Kaplan–Meier estimate and replacing their constituents with expected values based on the study's design parameters, formulae for projected standard errors can be produced. These formulae are shown, through simulations, to be quite accurate. Copyright © 2001 John Wiley & Sons, Ltd.
Item response models for joint analysis of quality of life and survival
Authors: Wang Chen , Douglas Jeffrey , Anderson Susan 
Published: August 2002

AbstractA complication when assessing quality of life data longitudinally is that in many trials a substantial percentage of patients die before completing all of the assessments. Furthermore, a patient's risk of dying might be predicted by his current quality of life. This suggests jointly modelling quality of life and survival, and using this combined information to summarize the outcome. The aim of this paper is to address the complicated issues, such as death, present in analysing multiple‐item ordinal quality of life data in clinical trials while recognizing the psychometric properties of the quality of life instrument being used. This is done by combining an item response model and Cox's proportional hazard model, where a latent variable process for quality of life determines the probability of selecting various options on quality of life items, and also serves as a time‐dependent covariate in the survival model. We accomplish this by using Markov chain Monte Carlo methods to obtain parameter estimates. Then we compute a summary measure, area‐under‐QOL curve, to compare the efficacy of the treatments. The methods are illustrated with analysis of data from the Vesnarinone trial of patients with severe heart failure, in which quality of life was assessed with the Minnesota Living with Heart Failure Questionnaire. Copyright © 2002 John Wiley & Sons, Ltd.