bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of aquatic mosses on juvenile fish density and habitat use in the regulated River Suldalslågen, western Norway
Authors: Heggenes Jan , Saltveit Svein Jakob 
Published: October 2002

AbstractTwo morphologically distinct moss communities were found in the River Suldalslågen. The liver moss community consists of species which form a dense mat on the bottom, while the river moss (Fontinalis) community forms long tufts. Moss growth has increased since hydropower regulations due to reduced floods and increased winter flows. Increased moss cover affects the bottom structure, as well as intra‐gravel and near‐bottom hydraulics. We studied densities of juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) by electrofishing and habitat selection by direct underwater observation, in areas with natural moss cover compared with areas where mosses were experimentally removed. Areas with dense mats of liver mosses held lower densities of young of year (YoY) and older salmon parr than areas where liver moss had been removed. No differences in densities of YoY salmon were found between areas with and without Fontinalis. For older salmon, parr results were inconclusive. In some samples more and in others fewer fish were found in areas with Fontinalis moss removed. For trout, densities were higher in areas with Fontinalis, while results for liver moss were inconclusive. No major differences were found with regard to microhabitat selection between areas with and without river moss, suggesting that habitat quality in these areas was similar during summer, except with respect to substrate. Salmon held more exposed positions in areas without liver moss, but this is mainly attributed to different habitat availabilities. It is concluded that the relative increase in liver mosses in the River Suldalslågen has a negative impact on juvenile Atlantic salmon fish density. Copyright © 2002 John Wiley & Sons, Ltd.
Recognition of indoor images employing supporting relation between objects
Authors: Yanai Keiji , Deguchi Koichiro 
Published: October 2002

AbstractIn this paper, we describe a new design of a recognition system for a single image of an indoor scene including complex occlusions. In conventional works, the systems could not recognize images of an indoor scene including complex occlusions. Our system can treat them by employing supporting relation between objects. In our system, first, the system estimates the 3D structure of an object by fitting a 3D structure model to the image qualitatively. Next, by checking the supporting relation between objects, it eliminates object candidates that cannot exist and estimates real objects from their parts in the image. Finally, the system recognizes objects that are compatible with each other. We implemented the system as a multi‐agent‐based image understanding system. In this paper, we describe the design of the system and results of experiments. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(11): 14–26, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10142
Shape from contour using adaptive image selection
Authors: Akutsu Takashi , Arakawa Ken‐ichi , Murase Hiroshi 
Published: October 2002

AbstractThe “shape‐from‐contour method” reconstructs the 3D shape of the surface of an object by extracting its contour from each of a series of successive images of the object. This can be realized by using a CCD camera, and is a relatively accurate method of obtaining environmental information. However, to obtain an accurate result, many images must be processed. Therefore, it is important to select the images depending on their effect on the final result, particularly for high‐speed processing.This paper proposes an adaptive image selection (AISE) method which depends on the required accuracy. The method has been applied to objects having various cross‐sectional shapes. The errors in shape reconstruction and the number of images required in the conventional method and the proposed method are compared. The experimental results show that the proposed method requires fewer images than the conventional method, particularly when the surface curvature of the object has large variation. The theoretical relationship between the accuracy of the reconstructed shape and the number of images required is also derived. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(11): 50–60, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1163
AES study on the interface diffusion and reaction between Cr layer and Si3N4/Si substrate
Authors: Zhu Yongfa , Wang Li , Yao Wenqing , Cao Lili 
Published: October 2002

AbstractA Cr layer of thickness 190 nm was successfully deposited on the surface of Si3N4/Si substrate using magnetron sputtering in d.c. mode. Auger electron spectroscopy analysis indicated that the interface diffusion was very weak during the deposition. Annealing treatments in the temperature range 300–760 °C in high vacuum were performed in order to promote interface diffusion and reaction between the Cr layer and the Si3N4/Si substrate. Auger electron spectroscopy results indicated that the interface diffusion and reaction took place between the Cr layer and the Si3N4 layer to form CrNxSiy species at 600 °C and was enhanced with increase in temperature. Simultaneously, Si depleted from Si substrate and diffused gradually into the Cr layer through the Si3N4 layer. After the temperature reached 760 °C, most of the Si3N4 species decomposed and a CrSi layer of ∼210 nm formed, indicating that the annealing temperature was the key step in the interface reaction. Interface diffusion and reaction can be enhanced by increasing the temperature or the annealing time. Copyright © 2002 John Wiley & Sons, Ltd.
In situ interfacial analysis of evaporated potassium on the electroluminescent fluorene–thiophene copolymer
Authors: Ling Q. D. , Li S. , Kang E. T. , Neoh K. G. , Liu B. , Huang Wei 
Published: October 2002

AbstractX‐ray photoelectron spectroscopy (XPS) was used to investigate the interface formation during in situ thermal evaporation of potassium on thin films of an electroluminescent conjugated polymer: poly[2,7‐(9,9‐dihexylfluorene)‐co‐alt‐2,5‐(decylthiophene)] (PFT). The chemical state and composition of the metal/polymer interfaces were studied as a function of the potassium coverage. Potassium was found to interact extensively with the bulk‐adsorbed oxygen to form a layer of metal oxide at the K/PFT interface. Migration of the bulk‐adsorbed oxygen to the surface occurred in response to the deposition of potassium onto the polymer. The changes in the S 2p lineshape suggested the formation of a thiolate species at low potassium coverages and also a sulphide species at higher metal coverages. The presence of charge transfer from the deposited potassium atoms to the carbon atoms of PFT suggested that the polymer had undergone n‐type doping. The deposited potassium atoms also diffused into the subsurface region of the polymer film. Thus, the interface of K/PFT contained mainly the oxidized metal, metallic potassium and metal–polymer charge transfer complexes. Copyright © 2002 John Wiley & Sons, Ltd.
Influence of ESCA analyser acceptance angle on measured thickness of thin oxide layers
Authors: Nylund Anders 
Published: October 2002

AbstractA theoretical model that takes the influence of the photoelectron take‐off angle and the acceptance angle of the ESCA analyser on the photoelectron intensity into account is outlined. From a known oxide thickness, theoretical oxide and metal intensities are estimated for take‐off angles ranging from 10° to 90°. The model shows good agreement with experimental values recorded from thin aluminium oxide layers of thickness 15 and 23 Å. The model further shows that the oxide thickness estimated from the intensities is lower than the nominal value for the smallest take‐off angles. This behaviour is more pronounced for the larger acceptance angles and is confirmed by experimental results. To compensate for the influence of the acceptance angle on the calculated oxide thickness, an experimentally determined effective take‐off angle must be introduced at the lowest take‐off angles. The ESCA spectrometer used was a PHI 5500 with acceptance angles of ±2°, ±5° and ±7°. Copyright © 2002 John Wiley & Sons, Ltd.
Surface‐core‐level‐shift photoelectron diffraction of Yb(111) films grown on W(110)
Authors: Dávila M. E. , Molodtsov S. L. , Laubschat C. , Asensio M. C. 
Published: October 2002

AbstractQuantitative analysis of the surface relaxation of thick Yb(111) films grown on W(110) has been performed by photoelectron diffraction (PED) using high‐energy resolution Yb 4f surface core‐level‐shift photoemission spectra. Scanned PED spectra were measured by recording the intensity variation of the bulk and the surface components of the 4f7/2 and 4f5/2 emissions over a photon energy range 140–260 eV for different experimental geometries. Additionally, angular scans for a fixed photon energy of 150 eV were recorded in the crystal high symmetry directions. Analysis of the data set following a trial‐ and ‐error procedure confirmed that Yb grows epitaxially in an fcc structure, without surface reconstruction. The obtained bulk lattice parameter corresponds to 5.44 Å, which is ∼1% contracted with respect to the natural crystal. From the PED surface components an inward relaxation by 3.6 ± 0.3% of the outermost surface layer of Yb is obtained. Copyright © 2002 John Wiley & Sons, Ltd.
A weighted estimating equation for linear regression with missing covariate data
Authors: Parzen Michael , Lipsitz Stuart R. , Ibrahim Joseph G. , Lipshultz Steven 
Published: October 2002

AbstractLinear regression is one of the most popular statistical techniques. In linear regression analysis, missing covariate data occur often. A recent approach to analyse such data is a weighted estimating equation. With weighted estimating equations, the contribution to the estimating equation from a complete observation is weighted by the inverse ‘probability of being observed’. In this paper, we propose a weighted estimating equation in which we wrongly assume that the missing covariates are multivariate normal, but still produces consistent estimates as long as the probability of being observed is correctly modelled. In simulations, these weighted estimating equations appear to be highly efficient when compared to the most efficient weighted estimating equation as proposed by Robins et al. and Lipsitz et al. However, these weighted estimating equations, in which we wrongly assume that the missing covariates are multivariate normal, are much less computationally intensive than the weighted estimating equations given by Lipsitz et al. We compare the weighted estimating equations proposed in this paper to the efficient weighted estimating equations via an example and a simulation study. We only consider missing data which are missing at random; non‐ignorably missing data are not addressed in this paper. Copyright © 2002 John Wiley & Sons, Ltd.
Meta‐analysis combining parallel and cross‐over clinical trials. III: The issue of carry‐over
Authors: Curtin François , Elbourne Diana , Altman Douglas G. 
Published: October 2002

AbstractIn meta‐analysis combining results from parallel and cross‐over trials, there is a risk of bias originating from the carry‐over effect in cross‐over trials. When pooling treatment effects estimated from parallel trials and two‐period two‐treatment cross‐over trials, meta‐analytic estimators of treatment effect can be obtained from the combination of parallel trial results either with cross‐over trial results based on data of the first period only or with cross‐over trial results analysed with data from both periods. Taking data from the first cross‐over period protects against carry‐over but gives less efficient treatment estimators and may lead to selection bias. This study evaluates in terms of variance reduction and mean square error the cost of calculating meta‐analysis estimates with data from the first period instead of data from the two cross‐over periods. If the information on cross‐over sequence is available, we recommend performing two combined design meta‐analyses, one using the first cross‐over period data and one based on data from both cross‐over periods. To investigate simultaneously the statistical significance of these two estimators as well as the carry‐over at meta‐analysis level, a method based on a multivariate analysis of the meta‐analytic treatment effect and carry‐over estimates is proposed. Copyright © 2002 John Wiley & Sons, Ltd.
Acquiring knowledge by foreign partners from international joint ventures in a transition economy: learning‐by‐doing and learning myopia
Authors: Tsang Eric W. K. 
Published: October 2002

AbstractThis paper proposes and tests a model of how firms acquire knowledge from their international joint venturing experience. Based on survey responses from 73 Singapore and 89 Hong Kong firms with respect to their joint ventures set up in China, the results indicate that both overseeing effort and management involvement are significant channels of knowledge acquisition. The former channel is more important for firms with a great deal of operational experience in China and for parents of older joint ventures. This finding indicates that firms improve their skills of knowledge acquisition through learning‐by‐doing. Moreover, the strategic importance of the venture concerned, instead of the learning intent of the parent, is the driving force behind the allocation of resources to the two channels. This implies that firms mainly learn through managing their key joint ventures. Since a venture that provides novel and fruitful learning experience may not, and need not, be an operation of great strategic importance, this finding suggests the existence of learning myopia. Copyright © 2002 John Wiley & Sons, Ltd.
Automatic layout of statecharts
Authors: Castello Rodolfo , Mili Rym , Tollis Ioannis G. 
Published: October 2002

AbstractGraphical notations are widely used for system specification. The usefulness of these notations depends primarily on their readability. Hence, automatic methods are needed to obtain efficient and understandable graphical representations of requirements. In this paper, we present an algorithm that automatically generates layouts of statecharts. We assume that relevant information is stored in a structure that we call a decomposition tree, and we draw the graph that models a statechart in a hierarchical fashion. Our approach excludes diagrams with inter‐level transitions. Copyright © 2001 John Wiley & Sons, Ltd.
Lightweight validation of natural language requirements
Authors: Gervasi Vincenzo , Nuseibeh Bashar 
Published: October 2002

AbstractIn this paper, we report on our experiences of using lightweight formal methods for the partial validation of natural language requirements documents. We describe our approach to checking properties of models obtained by shallow parsing of natural language requirements, and apply it to a case study based on part of a NASA specification of the Node Control Software on the International Space Station. The experience reported supports our position that it is feasible and useful to perform automated analysis of requirements expressed in natural language. Indeed, we identified a number of errors in our case study that were also independently discovered and corrected by NASA's Independent Validation and Verification Facility in a subsequent version of the same document, and others that were not discovered. The paper describes the techniques we used, the errors we found and reflects on the lessons learned. Copyright © 2001 John Wiley & Sons, Ltd.
Instrumenting and tuning dataView—a networked application for navigating through large scientific datasets
Authors: Slottow Joan , Shahriari Ali , Stein Michael , Chen Xiao , Thomas Chris , Ender Philip B. 
Published: October 2002

AbstractdataView is an application that allows scientists to fly visually through large, regularly‐gridded, time‐varying 3D datasets from their desktop computers. dataView works with data that has been divided into cubes and sub‐cubes (which we call ‘tiles’ and ‘subtiles’), sampled at three levels of detail and written to a terabyte data server built on a PC cluster. dataView is a networked application. The dataView client component that runs on the scientist's computer is used only for user interaction and rendering. The selection of data subtiles for any given scene, and the geometry computation performed on those subtiles to create the virtual world, are performed by dataView components run in parallel on nodes of the PC cluster.This paper describes how we instrumented and tuned the code for improved performance in a networked environment. We report on how we measured network performance, first by inducing network delay and then by running the dataView client component in Washington DC and the compute components in Los Angeles. We report on the effect that tile size, level of detail, and client CPU speed have on performance. We analyze what happens when the geometry computation is performed in parallel using MPI (Message Passing Interface) vs. in serial, and discuss the effect on performance of adding additional computational nodes. Copyright © 2001 John Wiley & Sons, Ltd.
MOLE: A mobile agent system
Authors: Baumann J. , Hohl F. , Rothermel K. , Strasser M. , Theilmann W. 
Published: October 2002

AbstractDue to its salient properties, mobile agent technology has received rapidly growing attention over the last few years. Many developments ofmobile agent systems are under way in both academic and industrial environments. MOLE is one of the first mobile agent systems that has been developed in the Java language; the first version came out in 1995. Since then MOLE has been constantly improved, and provides a stable environment for development and usage of mobile agents in the area of distributed applications. Furthermore, it has been used extensively in our research at the University of Stuttgart.In this paper we describe the system MOLE, some of its unique concepts and their implementation, and the results of our research in the areas of security, transactional support, and control mechanisms. Additionally, we discuss some applications built on MOLE. Copyright © 2002 John Wiley & Sons, Ltd.
An object‐oriented tool for simulating distributed real‐time control systems
Authors: Palopoli Luigi , Lipari Giuseppe , Lamastra Gerardo , Abeni Luca , Bolognini Gabriele , Ancilotti Paolo 
Published: October 2002

AbstractThis paper presents an object‐oriented software tool, called RTSIM, aimed at simulating real‐time embedded controllers. The tool consists of a collection of C++ libraries permitting a separate specification of the functional behaviour of the controller and of the hardware/software architecture to be used for its deployment. In particular, it is possible to provide an accurate modelling of the concurrent architecture of the control tasks and of the run‐time support offered by the operating system for the real‐time scheduling of the shared resources (CPU, memory buffers and network links). In this way, it is possible to compare different scheduling solutions by evaluating their simulated performance directly in the domain of the control application. Moreover, the tool can be utilized to tune up design parameters such as the activation frequencies of the tasks. The application of the tool is shown in a meaningful case study. Copyright © 2002 John Wiley & Sons, Ltd.
Additional transformations for multiple‐level escape statements
Authors: Olsson Ronald A. 
Published: October 2002

AbstractEarlier work suggests that program transformations can simplify program verification. A given program containing complex language features is transformed into a semantically equivalent program containing only simpler language features. The transformed program is proven using a set of proof rules for only the simpler features. That approach was illustrated by transforming a given program that may contain multiple‐level escape statements within nested loops into an equivalent program that contains no escape statements. This paper gives additional transformations, which map a given program that may contain multiple‐level escape statements to a semantically equivalent program (TP) that contains only single‐level escape statements. The proof of TP uses proof rules for single‐level escape statements, or the earlier transformations further map TP to a program with no escape statements, whose proof uses proof rules for loops without escape statements. This paper also discusses escape statements where the number of levels is determined at run‐time. Copyright © 2002 John Wiley & Sons, Ltd.
Gabaergic modulation of the stress response in frontal cortex and amygdala
Authors: Martijena I.D. , Rodríguez Manzanares P.A. , Lacerra C. , Molina V.A. 
Published: October 2002

AbstractGABAergic neurotransmission is thought to play an important role in the modulation of the central response to stress. In the present study we evaluate the influence of a brief restraint exposure on GABA‐stimulated chloride influx in diverse brain areas presumed to have a major role in the mediation of emotional behaviors following aversive stimulation. A reduced chloride uptake after stress exposure was only observed in frontal cortex and amygdala. Moreover, rats subjected to such stressor performed an anxiogenic behavior when exposed later to the elevated plus‐maze. A comparable behavior in the elevated plus‐maze was observed between animals that were allowed to chew during the restraint experience and those without any stressful manipulation, suggesting that chewing served as an efficient coping behavioral strategy during such threatening situations. In order to explore if chewing during the restraint experience could suppress the reduction in GABA‐stimulated chloride uptake induced by this stressor, rats were allowed or not to chew during restraint and in both cases GABA‐stimulated chloride influx was assayed in frontal cortex and amygdala. The finding of this experiment showed that restrained rats that have the possibility to chew exhibited a similar GABA‐stimulated chloride uptake in cortical tissue to that shown by control, unstressed rats. Moreover, chewing in response to restraint attenuated the reduction of GABA‐stimulated chloride uptake in amygdala, supporting the notion that chewing is an effective coping response to restraint. These experiments suggest that a reduced GABAergic inhibitory control in these areas could be implicated in the emotional sequelae generated by this uncontrollable stressor and that the suppression of this reduction seems to be associated with the occurrence of coping behavioral response to such fear‐inducing stimulus. Synapse 45:86–94, 2002. © 2002 Wiley‐Liss, Inc.