bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scene‐adaptive switching of segmentation methods for object‐based video encoding
Authors: Misu Toshihiko , Sonehara Hajime , Zheng Wentao , Naemura Masahide , Kanatsugu Yasuaki , Izumi Yoshinori , Tanaka Yutaka 
Published: May 2004

AbstractIn order to create efficient object‐based video encoding, the authors have proposed a scene‐adaptive region segmentation method that can work with a variety of different types of scenes. In their method, encoding efficiency is improved by adaptively selecting for each frame the optimal method from among several different region segmentation methods determined using Bayesian decision‐making based on the video features of a scene. In this paper, the authors describe the Bayesian decision and training methods, and then formalize the image features and the different region segmentation methods. Finally, the authors demonstrate the validity of the proposed approach through experiments. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(8): 31–44, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10593
A method of knowledge modeling and its application to gene function analysis
Authors: Matsunaga Tsutomu 
Published: May 2004

AbstractThis paper proposes a knowledge model for large‐scale knowledge structurization of documents. When an elementary concept such as input for information retrieval is handled as an object, generally a structure composed of the relations in the set of objects is observed. The proposed model generates objects by statistical machine learning of the occurrence patterns of words in the word set and quantifies the relations among the objects by matching to the occurrence patterns. The idea is to approach knowledge structurization in order to achieve systematic understanding by relating pieces of existing knowledge by quantifying the relations among objects as elementary concepts. In this paper, the proposed model is applied to problems in the life science field, where there is a strong requirement for new knowledge with a comprehensive overview, and its application to gene function analysis is discussed. Experimental results on the extraction of disease‐related genes as relations between genes and a disease, and on the estimation of gene functions combined with knowledge about organs, are presented and the effectiveness of the approach is demonstrated. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(8): 21–30, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10670
Camera parameter estimation from a long image sequence by tracking markers and natural features
Authors: Sato Tomokazu , Kanbara Masayuki , Yokoya Naokazu , Takemura Haruo 
Published: May 2004

AbstractCamera parameter recovery from an image sequence is very important in many applications such as 3D model reconstruction, object recognition, robot navigation, and mixed reality. However, there is a problem concerning the precision in camera parameter estimation from the image sequence, because feature tracking errors and estimation errors are accumulated. In this paper, we propose a camera parameter estimation method which is based on using a number of markers with known 3D position, color, and shape, as well as natural features. Initially, the camera parameters and 3D positions of natural features are estimated efficiently in every frame by tracking both these markers and natural features. The accumulation of estimated errors is then minimized by specifying additional markers in some frames of input and optimizing parameters globally through the whole input. In the experiments, some results of 3D reconstruction show the validity of the proposed method. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(8): 12–20, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10702
Modeling network growth with directional attachment and communities
Authors: Kimura Masahiro , Saito Kazumi , Ueda Naonori 
Published: May 2004

AbstractAiming to construct a more precise probabilistic model for the short‐term growth process of real‐world growing networks such as the Web, we propose a new network growth model and its learning algorithm. Unlike the conventional network growth models, we incorporate directional attachment and community structure for this purpose. We first show that the proposed model also exhibits a degree distribution with a power‐law tail. In experiments using real Web data, we demonstrate that prediction of the dynamics of a given growing network can be improved by incorporating directional attachment and community structure. In experiments using synthetic data, we also demonstrate that prediction performance can definitely be improved by incorporating community structure. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(8): 1–11, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10706
Interaction between peripheral optical flow and foveal depth perception
Authors: Watanabe Hiroshi , Umemura Hiroyuki , Yoshida Chisato , Matsuoka Katsunori 
Published: May 2004

AbstractUsing an immersive VR system (the “CAVE”), we investigated the sensitivity and threshold of depth order judgment in the central visual field by subjects placed in a visual environment that simulated optical flow, producing vection in a wide‐area visual field (front, floor, and both sides) associated with forward movement inside an endless toroidal tunnel. Experiments showed that when an optical flow is produced in the wide‐area visual field, the sensitivity and threshold of depth judgment exhibit a systematic change that depends on the direction of rotation. Possible explanations of this result are the use of an implicit reference plane by the subject, and change of body sensation in response to the peripheral visual field information. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(8): 107–116, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20021
Statistical analysis of MMR vaccine adverse events on aseptic meningitis using the case cross‐over design
Authors: Park Taesung , Ki Moran , Yi Sung‐Gon 
Published: May 2004

AbstractVaccination is quite effective in reducing the incidence of disease. However, it may cause some adverse events. For example, one of the adverse events of measles‐mumps‐rubella(MMR) vaccination is the occurrence of aseptic meningitis. Since the vaccination rate is usually quite high, it is not plausible to use popular study designs such as cohort or case‐control studies. We considered a case cross‐over design to investigate the association between MMR vaccination and aseptic meningitis in Korean children. We used the Cochran–Mantel–Haenszel(CMH) approach, and obtained a Mantel–Haenszel odds ratio estimator as a measure of association. However, the validity of case cross‐over design or the CMH approach in vaccine adverse studies has not been fully investigated. In this paper, through Monte Carlo simulation studies, we show the appropriateness of the case cross‐over design and the CMH approach. We also discuss alternative approaches such as Poisson regression using offset and a simple uniformity test. In conclusion, the case cross‐over design seems useful to investigate the association between vaccination and occurrence of acute adverse events. Copyright © 2004 John Wiley & Sons, Ltd.
Bayesian analysis of risk factors for anovulation
Authors: Liu Yan , Johnson Wesley O. , Gold Ellen B. , Lasley Bill L. 
Published: May 2004

AbstractTwo algorithms for assessing ovulatory status using daily urinary levels of oestrogen and progesterone metabolites have been applied to non‐clinic‐based, free‐living populations of women. These relatively new methods for assessing ovarian function have been used to assess the potential adverse effects of occupational and environmental exposures, such as smoking, on the reproductive health of women. One algorithm has been validated against serum hormone measurements and gives good sensitivity and specificity for anovulation. However, a gold standard is generally not available in epidemiologic field studies in which these daily urine samples are collected. In this paper, we used Bayesian methods to estimate: (i) the probability of occurrence of anovulation, (ii) the sensitivity and specificity of the two algorithms, and (iii) the association between anovulation and smoking and other risk factors in the absence of a perfect test. We evaluated the two published algorithms for assessing ovulatory status, based on their cross‐classified results applied to one randomly selected cycle from each woman in a sample of 338 employed women. We first assumed that the algorithms were independent, conditional on ovulatory status. Then, we used a dependence model to allow for correlation between the results of the two algorithms. We implemented a Bayesian logistic regression analysis that allowed the outcome measurement to be partially imperfect. We incorporated the posterior distributions for algorithm accuracy obtained from the dependence model as prior distributions for this logistic regression model. Then, we compared the results with those obtained from a standard multiple logistic approach using the algorithm determination of ovulatory status as if it were perfect. Our results indicated that increasing physical activity was associated with a significantly increased risk of anovulation; and smokers had a potentially, but not statistically significant, increased occurrence of anovulation. Copyright © 2004 John Wiley & Sons, Ltd.
Non‐parametric estimation of gap time survival functions for ordered multivariate failure time data
Authors: Schaubel Douglas E. , Cai Jianwen 
Published: May 2004

AbstractTimes between sequentially ordered events (gap times) are often of interest in biomedical studies. For example, in a cancer study, the gap times from incidence‐to‐remission and remission‐to‐recurrence may be examined. Such data are usually subject to right censoring, and within‐subject failure times are generally not independent. Statistical challenges in the analysis of the second and subsequent gap times include induced dependent censoring and non‐identifiability of the marginal distributions. We propose a non‐parametric method for constructing one‐sample estimators of conditional gap‐time specific survival functions. The estimators are uniformly consistent and, upon standardization, converge weakly to a zero‐mean Gaussian process, with a covariance function which can be consistently estimated. Simulation studies reveal that the asymptotic approximations are appropriate for finite samples. Methods for confidence bands are provided. The proposed methods are illustrated on a renal failure data set, where the probabilities of transplant wait‐listing and kidney transplantation are of interest. Copyright © 2004 John Wiley & Sons, Ltd.
Engineering information integration using object‐oriented mediator technology
Authors: Nyström Mattias , Risch Tore 
Published: May 2004

AbstractThe mechanical product development process uses many different software systems to virtually simulate the behaviour of a design. The present work deals with flexible and efficient integration using object‐oriented mediator technology that provides transparent access to distributed engineering systems. The use of mediator technology is investigated for semi‐automatically integrating engineering information resident in computer aided design systems with a Common Object Request Broker Architecture based application programming interface. The purpose is to provide engineering analysis applications access to computer aided design system information and computational methods through a declarative query language. We conclude that the use of a declarative query language for developing engineering applications shows great potential in terms of flexibility, development productivity, performance, and ease of use, compared with using a procedural programming language. The work also shows new use of mediator technology, declarative queries, and active rules within engineering information integration that traditionally is accomplished using procedural programming. Copyright © 2004 John Wiley & Sons, Ltd.
Can a simple measure of vigorous physical activity predict future mortality? Results from the OXCHECK study
Authors: Hillsdon Melvyn , Thorogood Margaret , Murphy Mike , Jones Lesley 
Published: May 2004

AbstractBackground:As epidemiological studies have become more complex, demands for short, easily administered measures of risk factors have increased. This study investigates whether such a measure of physical activity is associated with the risk of death from all causes and death from specific causes.Methods:A prospective follow-up study of 11 090 men and women, aged 35–64 years, recruited from five UK general practices who responded to a postal questionnaire in 1989. Self-reported frequency of vigorous-intensity physical activity and data on confounding factors were collected at baseline survey. Death notifications up to 31 December 2001 were provided by the Office for National Statistics. The relative risk (and 95% confidence interval) of dying associated with each level of exposure to physical activity was estimated by the hazard ratio in a series of Cox regression models.Results:After > 10 years' follow-up there were 825 deaths among the 10 522 subjects with no previous history of angina or myocardial infarction. Participation in vigorous exercise was associated with a significantly lower risk of all-cause mortality. Similar associations were found for ischaemic heart disease and cancer mortality, although the relationships were not significant at the 5% level.Conclusions:Simple measures of self-reported vigorous physical activity are associated with the risk of future mortality, at least all-cause mortality in a somewhat selected group. Interpretation of the finding should be treated with caution due to the reliance on self-report and the possibility that residual confounding may underlie the associations. Because moderate-intensity physical activity is also beneficial to health, short physical activity questionnaires should include measures of such physical activity in the future.
High‐resolution wide‐field surface plasmon microscopy
Authors: STABLER G. , SOMEKH M. G. , SEE C. W. 
Published: May 2004

SummaryThis paper describes the application of a Köhler illuminated high‐resolution wide‐field microscope using surface plasmons to provide the image contrast. The response of the microscope to a grating structure in both the Fourier and the image planes is presented to demonstrate image formation by surface waves. The effect of spatial filtering in the back focal (Fourier) plane to enhance image constrast is described. We also discuss how the surface wave contrast mechanism affects the imaging performance of the microscope and discuss factors that can be expected to lead to even greater improvements in lateral resolution and sensitivity.
Using the FIB to characterize nanoparticle materials
Authors: PERREY C. R. , CARTER C. B. , MICHAEL J. R. , KOTULA P. G. , STACH E. A. , RADMILOVIC V. R. 
Published: May 2004

SummaryIn the 1–100‐nm size regime, the properties of materials can differ significantly from those of their bulk counterparts. The present study applies the focused ion beam (FIB) tool to the characterization of nanoscale structures for scanning and transmission electron microscopy. The strength of this method is its ability to manufacture samples that cannot be produced using traditional means. The films of nanoparticles examined here are examples of such systems; the films are found to be not fully dense, composed of chemically heterogeneous areas and mechanically different from the substrate. Distinct advantages of the application of the FIB for characterization of nanoscale structures are highlighted for several nanoparticle structures. This successful application of FIB techniques provides a pathway to integrate the study of nanoscale production techniques and their resulting structure–property relationships.
Photosynthetic characteristics of dwarf and fringe Rhizophora mangle L. in a Belizean mangrove
Authors: CHEESEMAN J. M. , LOVELOCK C. E. 
Published: May 2004

ABSTRACTTwin Cays (Belize) is a highly oligotrophic mangrove archipelago dominated by Rhizophora mangle L. Ocean‐fringing trees are 3–7 m tall with a leaf area index (LAI) of 2.3, whereas in the interior, dwarf zone, trees are 1.5 m or less, and the LAI is 0.7. P‐fertilization of dwarf trees dramatically increases growth. As a partial explanation of these characteristics, it was hypothesized that differences in stature and growth rates would reflect differences in leaf photosynthetic capacity, as determined by the photochemical and biochemical characteristics at the chloroplast level. Gas exchange and chlorophyll fluorescence were used to compare photosynthesis of dwarf, fringe and fertilized trees. Regardless of zonation or treatment, net CO2 exchange (A) and photosynthetic electron transport were light saturated at less than 500 µmol photons m−2 s−1, and low‐light quantum efficiencies were typical for healthy C3 plants. On the other hand, light‐saturated A was linearly related to stomatal conductance (gs), with seasonal, zonal and treatment differences in photosynthesis corresponding linearly to differences in the mean gs. Overall, photosynthetic capacity appeared to be co‐regulated with stomatal conductance, minimizing the variability of Ci at ambient CO2 (and hence, Ci/Ca). Based on the results of in vitro assays, regulation of photosynthesis in R. mangle appeared to be accomplished, at least in part, by regulation of Rubisco activity.
Developmental process of sun and shade leaves in Chenopodium album L.
Authors: YANO S. , TERASHIMA I. 
Published: May 2004

ABSTRACTThe authors’ previous study of Chenopodium album L. revealed that the light signal for anatomical differentiation of sun and shade leaves is sensed by mature leaves, not by developing leaves. They suggested that the two‐cell‐layered palisade tissue of the sun leaves would be formed without a change in the total palisade tissue cell number. To verify that suggestion, a detailed study was made of the developmental processes of the sun and shade leaves of C. album with respect to the division of palisade tissue cells (PCs) and the data was expressed against developmental time (leaf plastochron index, LPI). The total number of PCs per leaf did not differ between the sun and shade leaves throughout leaf development (from LPI −1 to 10). In both sun and shade leaves, anticlinal cell division of PCs occurred most frequently from LPI −1 to 2. In sun leaves, periclinal division of PCs occurred synchronously with anticlinal division. The constancy of the total number of PCs indicates that periclinal divisions occur at the expense of anticlinal divisions. These results support the above suggestion that two‐cell‐layered palisade tissue is formed by a change of cell division direction without a change in the total number of PCs. PCs would be able to recognize the polarity or axis that is perpendicular to the leaf plane and thereby change the direction of their cell divisions in response to the light signal from mature leaves.
Petrographic and trace element analysis of uranium‐rich tufa calcite, middle Miocene Barstow Formation, California, USA
Authors: Cole Jennifer M. , Rasbury E. Troy , Montañez Isabel P. , Pedone Vicki A. , Lanzirotti Antonio , Hanson Gilbert N. 
Published: May 2004

AbstractAn integrated petrographic and spectroscopic (X‐ray diffraction, phosphor imaging and synchrotron X‐ray absorption spectroscopy) study of tufas from the Miocene Barstow Formation, California, relates sample morphology, mineralogy and geochemical composition. The tufas, composed mainly of calcite that formed at the interface between an ancient alkaline lake and ground or spring waters, have textures similar to those of microbially mediated terrestrial stromatolites and travertines. The tufas have elevated concentrations of a number of trace elements including Mn, Fe, Sr and U. Synchrotron X‐ray fluorescence analyses show that U concentrations can exceed 500 p.p.m. X‐ray absorption spectroscopy indicates that the U in these samples is incorporated as U(IV). It is suggested here that alkaline lake waters had a high U/Ca ratio and tufa calcite formed where groundwater or (possibly epithermal) springs brought in Ca and trace elements such as Sr. The rapid, and possibly microbially mediated, precipitation of calcite allowed for incorporation of high concentrations of trace metals as either structural substitutes or extremely fine‐scale inclusions.
The cyclic hierarchy of the ‘Purbeckian’ Sierra del Pozo Section, Lower Cretaceous (Berriasian), southern Spain
Authors: Anderson Edwin J. 
Published: May 2004

AbstractThe lowermost Cretaceous (Berriasian) Sierra del Pozo Formation is divisible into metre‐scale cycles that are bundled in a four‐tiered hierarchy of cycles and cyclic sequences. At the smallest scale, sixth‐order cycles, thought to be the product of precessionally forced sea‐level fluctuations (c. 20 ka), average less than a metre in thickness, shallow upward and are bounded by surfaces where deeper facies abruptly overlie shallower facies. Bundles of sixth‐order cycles, called fifth‐order sequences, are recognized by two types of asymmetric patterns in facies distribution. First, more pronounced facies changes occur at sixth‐order cycle boundaries lower in a sequence, whereas smaller facies changes occur at cycle boundaries higher in a sequence. Secondly, subtidal marine limestones (i.e. biomicrites and biosparites) are the dominant facies lower in a cyclic sequence, whereas more restricted or shallower water facies (i.e. mud‐cracked microbial laminites, dolomites, shale and clay) are more predominant higher in a cyclic sequence. The bundling of sixth‐order cycles is explained as a product of periodic change (100 ka) in the eccentricity of the earth's orbit. The degree of orbital eccentricity modulates the magnitude of precessional sea‐level fluctuations, which in turn determine the relative facies contrasts at sixth‐order cycle boundaries. Larger scale fourth‐ and third‐order sequences are defined by similar patterns in facies contrast at successive sequence boundaries and by a change in predominant facies type from bottom to top. These patterns are explained as the product of 400 ka and 2 Ma periodic variations in the eccentricity of the earth's orbit. In summary, the strength of the precessional signal varies in consort with periodic changes in orbital eccentricity at three time scales producing a stacked hierarchy of cycles and sequences of cycles. Change in obliquity of the earth's axis may modulate the effects of the precessional signal and thereby modify patterns of preserved cyclic structure. This interpretation of cyclicity in the Sierra del Pozo section is markedly different from that of Jiménez de Cisneros & Vera (1993), who attributed all rock cycles to a single process (obliquity) even though the cycles they described varied in thickness from less than 1 m to more than 4 m. The cycles they described are shown here to be either precessional cycles or composite sets of precessional cycles (100 ka sequences). In this new hierarchical interpretation, ninety‐six 100 ka and twenty‐four 400 ka sequences are recognized, extending the time of deposition of the Sierra del Pozo section to more than 9·6 Ma.