bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential quadrature finite difference method for structural mechanics problems
Authors: Chen Chang‐New 
Published: August 2002

AbstractThe differential quadrature finite difference method (DQFDM) has been proposed by the author. The finite difference operators are derived by the differential quadrature (DQ). They can be obtained by using the weighting coefficients for DQ discretizations. The derivation is straight and easy. By using different orders or the same order but different grid DQ discretizations for the same derivative or partial derivative, various finite difference operators for the same differential or partial differential operator can be obtained. Finite difference operators for unequally spaced and irregular grids can also be generated through the use of generic differential quadrature (GDQ). The derivation of higher‐order finite difference operators is also easy. By adopting the same order of approximation for all mathematical terms existing in the problem to be solved, excellent convergence can be obtained due to the consistent approximation.The DQFDM is effective for solving structural mechanics problems. The numerical simulations for solving anisotropic nonuniform plate problems and two‐dimensional plane elasticity problems are carried out. Numerical results are presented. They demonstrate the DQFDM. Copyright © 2001 John Wiley Sons, Ltd.
An appropriate quadrature rule for the analysis of plane crack problems in the boundary‐element method
Authors: Theotokoglou E. E. , Tsamasphyros G. 
Published: August 2002

AbstractAn hypersingular integral equation of a three‐dimensional elastic solid with an embedded planar crack subjected to a uniform stress field at infinity is derived. The solution of the boundary‐integral equation is succeeded taking into consideration an appropriate Gauss quadrature rule for finite part integrals which is suitable for the numerical treatment of any plane crack with a smooth‐contour shape and permit the fast convergence for the results. The problem of a circular and of an elliptical crack in an infinite body subjected to a uniform stress field at infinity is confronted; and the stress intensity factors are calculated. Copyright © 2001 John Wiley & Sons, Ltd.
Accurate modal perturbation in non‐self‐adjoint eigenvalue problem
Authors: Liu X. L. 
Published: August 2002

AbstractThis paper presents an algorithm for the accurate modal perturbation analysis in the non‐self‐adjoint eigenvalue problem. Complete perturbation items are obtained from the given straightforward process, satisfying two conditions in a modal analysis: the eigenvalue equations and normality condition. The zeroth‐order perturbation, solved from equations in a form of Rayleigh quotient, is employed in the later perturbations, which helps to improve the accuracy of analysis. Two examples are given to show the modal perturbation with distinct eigenvalues and with close eigenvalues. It is confirmed that the algorithm is applicable to any mode with a distinct eigenvalue, repeated eigenvalues, or close eigenvalues, and can give an improved accuracy. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of boundary conditions on a class of mixed discontinuous finite element methods for reaction–diffusion problems
Authors: Chen Zhangxin 
Published: August 2002

AbstractThis paper numerically studies the effects of boundary conditions of different types on a class of mixed discontinuous finite element methods. The focus of this study is on a reaction–diffusion problem in one space dimension, which arises in the modelling and simulation of fluid flows in porous media. Numerical results show that for boundary conditions of certain types these mixed discontinuous methods produce an optimal rate of convergence; for others they generate a sub‐optimal rate of convergence. A lower‐order term is included in the reaction–diffusion problem, so the numerical study applies to a time‐dependent problem as well. Copyright © 2002 John Wiley & Sons, Ltd.
Camera characterization for color research
Authors: Barnard Kobus , Funt Brian 
Published: August 2002

AbstractIn this article we introduce a new method for estimating camera sensitivity functions from spectral power input and camera response data. We also show how the procedure can be extended to deal with camera nonlinearities. Linearization is an important part of camera characterization, and we argue that it is best to jointly fit the linearization and the sensor response functions. We compare our method with a number of others, both on synthetic data and for the characterization of a real camera. All data used in this study is available online at www.cs.sfu.ca/∼colour/data. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 152–163, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/col.10050
On the relationship between tilt of a*b* tolerance ellipses in blue region and tritanopic confusion lines
Authors: Yebra A. , Huertas R. , Pérez M. M. , Melgosa M. 
Published: August 2002

AbstractThere is reasonable agreement between the orientation of the major axes of the a*b* tolerance ellipses in the blue region and the slope of the tritanopic confusion lines passing through their centers. This agreement includes some experimental facts such as the approximate constant orientation of the ellipses when the luminance of the center changes and the clockwise rotation of the major axis of the ellipses when the luminous source D65 is replaced by A. However, the tilts predicted by the tritanopic lines do not follow the pattern proposed by the CIEDE2000 color‐difference formula; in particular, for the blue‐green centers with hue angles lower than 255°, the high tilts predicted by the tritanopic lines are quite different. From 132 ellipses previously reported, we found that the orientations of the 17 ellipses in the blue region (255° < h < 320°) were similarly predicted by both CIEDE2000 and the tritanopic confusion lines (average error of 12.2° in absolute value). © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 180–184, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10053
The usability of the CIE colour‐matching functions in the case of CRT monitors
Authors: Borbély Ákos , Schanda János 
Published: August 2002

AbstractDuring the past years, several papers have been published that question the use of the CIE colour‐matching functions in the case of metameric samples. Visually matching samples produced on CRT (Cathode Ray Tube) monitors are metameric to most colour stimuli created by illuminating reflecting materials. As CRT monitors are often used in colour design applications, it seemed important to check how well CIE colorimetry will predict such colour matches. To investigate this problem, we set up an experiment in which painted samples were matched with samples produced on a CRT monitor.The colour of incandescent lamp irradiated Munsell samples were visually matched to the mixture of the RGB primaries of a CRT monitor. Both the reflected colour stimuli of the Munsell samples and the emitted stimuli of the monitor were measured spectroradiometrically.Our results imply that there is an observer‐dependent variability among the matches, but we could not find a major difference between the tristimulus data of the hard copy and soft copy presentations that would indicate errors in the CIE colour‐matching functions. The measurement accuracy, quantization errors of the monitor, and the achieved accuracy of the colour matches are treated in this study. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 436–441, 2001
On the Boltzmann equation for long‐range interactions
Authors: Alexandre R. , Villani C. 
Published: August 2002

AbstractWe study the Boltzmann equation without Grad's angular cutoff assumption. We introduce a suitable renormalized formulation that allows the cross section to be singular in both the angular and the relative velocity variables. Angular singularities occur as soon as one is interested in long‐range interactions, while singularities in the relative velocity variable occur in the study of soft potentials, in particular, Coulomb interaction. Together with several new estimates, this new formulation enables us to prove existence of weak solutions and to give a proof of a conjecture by Lions (appearance of strong compactness) under general, fully realistic assumptions. © 2001 John Wiley & Sons, Inc.
A free boundary problem for a quasi‐linear degenerate elliptic equation: Regular reflection of weak shocks
Authors: Čanić Sunčica , Keyfitz Barbara Lee , Kim Eun Heui 
Published: August 2002

AbstractWe prove the existence of a solution to the weak regular reflection problem for the unsteady transonic small disturbance (UTSD) model for shock reflection by a wedge. In weak regular reflection, the state immediately behind the reflected shock is supersonic and constant. The flow becomes subsonic further downstream; the equation in self‐similar coordinates is degenerate at the sonic line. The reflected shock becomes transonic and begins to curve there; its position is the solution to a free boundary problem for the degenerate equation. Using the Rankine‐Hugoniot conditions along the reflected shock, we derive an evolution equation for the transonic shock, and an oblique derivative boundary condition at the unknown shock position. By regularizing the degenerate problem, we construct uniform bounds; we apply local compactness arguments to extract a limit that solves the problem. The solution is smooth in the interior and continuous up to the degenerate boundary.This work completes a stage in our program to construct self‐similar solutions of two‐dimensional Riemann problems. In a series of papers, we developed techniques for solving the degenerate elliptic equations that arise in self‐similar reductions of hyperbolic conservation laws. In other papers, especially in joint work with Gary Lieberman, we developed techniques for solving free boundary problems of the type that arise from Rankine‐Hugoniot relations. For the first time, in this paper, we combine these approaches and show that they are compatible. Although our construction is limited to a finite part of the unbounded subsonic region, it suggests that this approach has the potential to solve a variety of problems in weak shock reflection, including Mach and von Neumann reflection in the UTSD equation, and the analogous problems for the unsteady full potential equation. © 2002 John Wiley & Sons, Inc.
Open consensus
Authors: Boichat Romain , Frølund Svend , Guerraoui Rachid 
Published: August 2002

AbstractThis paper presents the abstraction of open consensus and argues for its use as an effective component for building reliable agreement protocols in practical asynchronous systems where processes and links can crash and recover. The specification of open consensus has a decoupled, on‐demand and re‐entrant flavour that make its use very efficient, especially in terms of forced logs, which are known to be major sources of overhead in distributed systems. We illustrate the use of open consensus as a basic building block to develop a modular, yet efficient, total‐order broadcast protocol. Finally, we describe our Java implementation of our open‐consensus abstraction and we convey our efficiency claims through some practical performance measures. Copyright © 2001 John Wiley & Sons, Ltd.
Cellular non‐linear networks for minimization of functionals. Part 1: Theoretical aspects
Authors: Storace Marco , Bizzarri Federico , Parodi Mauro 
Published: August 2002

AbstractA method for the definition of cellular non‐linear networks able to find approximate minima of rather a large class of continuous functionals is proposed and discussed from a theoretical point of view. The method is based on the spatial discretization of continuous functionals and on the theory of potential functions for resistive circuits. The discretization of the continuous functionals is obtained by resorting to the finite difference method or to the finite element method. The spatial discretization converts a functional into a function of a finite set of variables. By exploiting the theory of potential functions for resistive circuits, from such a function one can derive a lumped circuit that makes it possible to find an approximate minimum of the given functional. Copyright © 2001 John Wiley & Sons, Ltd.
Probabilistic design of systems with general distributions of parameters
Authors: Ponnambalam K. , Seifi Abbas , Vlach Jiri 
Published: August 2002

AbstractThis paper presents a new method for finding optimal solutions of systems with design parameters which are random variables distributed with various general and possibly non‐symmetrical distributions. A double‐bounded density function is used to approximate the distributions. Specifications may require tracking constraints in time domain and stability conditions in frequency domain. Using sensitivity information, the proposed method first finds a linearized feasible region. Afterwards it attempts to place a tolerance box of the design parameters such that the region with higher yield lies in the feasible region. The yield is estimated by the joint cumulative density function over a portion of the tolerance box contained in the feasible region. Optimal designs are found for a fourth‐order servomechanism and actual yields are evaluated by Monte‐Carlo simulation. Copyright © 2001 John Wiley & Sons, Ltd.
Existence and uniqueness of solutions for DC networks containing non‐linear ideal op amps
Authors: Ciampa Maurizio 
Published: August 2002

AbstractIn this paper we are concerned with networks obtained by connecting independent sources, linear resistors and non‐linear ideal op amps. A necessary and sufficient condition for the existence and uniqueness of solutions for every positive output saturation voltage of the op amps and every value of the independent sources is found. Copyright © 2001 John Wiley & Sons, Ltd.
Transcriptional profiling develops molecular signatures for ovarian tumors
Authors: Smith David I. 
Published: August 2002

AbstractOf the cancers unique to women, ovarian cancer has the highest mortality rate. Over 26,000 women are diagnosed with this disease in the U.S. annually, and 60% of those diagnosed will die of the disease. One of the greatest problems with this disease is the lack of strong early warning signs or symptoms resulting in advanced stage at presentation in most women, followed by the outgrowth of chemotherapy‐resistant disease in the majority of patients. The 5‐year survival for patients with early stage disease ranges from 50‐90%, but it is less than 25% for advanced‐stage disease. In collaboration with researchers at Millennium Predictive Medicine (Cambridge, MA), the Ovarian Cancer Program of the Mayo Clinic Cancer Center analyzed gene expression in over 50 primary ovarian tumors, as compared with normal ovarian epithelial cells. The technologies utilized included microarray analysis with nitrocellulose filters containing 25,000 arrayed human cDNAs, as well as the construction of subtraction suppression hybridization cDNA libraries and their subsequent sequencing. Our specific focus has been on genes that are underexpressed during the development of ovarian cancer, although this analysis has revealed a large number of consistently up‐ and down‐regulated genes. There were more down‐regulated genes in ovarian tumors than up‐regulated genes. In addition, the number of genes that had altered expression levels was quite large. For example, we found 409 genes down‐regulated at least 5‐fold, and 72 genes up‐regulated at least 5‐fold in 33% of the tumors analyzed. We also observed that most of the expression alterations observed in later stage (Stages III/IV) tumors were also observed in early‐stage tumors (Stages I/II). This was corroborated using comparative genomic hybridization analysis on the same tumors that were expression profiled. This analysis revealed that the late‐stage tumors had more gene amplification than early‐stage tumors, but most regions of change (either increases or decreases) were in common between different stage tumors. We also have verified the altered expression levels of several of these genes using several complementary strategies. Finally, we are taking top candidate genes that are consistently under‐expressed in ovarian tumors and attempting to determine their functional role in the development of ovarian cancer. Cytometry 47:60–62, 2002. © 2001 Wiley‐Liss, Inc.
Magnetic field design for selecting and aligning immunomagnetic labeled cells
Authors: Tibbe Arjan G.J. , de Grooth Bart G. , Greve Jan , Dolan Gerald J. , Rao Chandra , Terstappen Leon W.M.M. 
Published: August 2002

AbstractBackgroundRecently we introduced the CellTracks cell analysis system, in which samples are prepared based on a combination of immunomagnetic selection, separation, and alignment of cells along ferromagnetic lines. Here we describe the underlying magnetic principles and considerations made in the magnetic field design to achieve the best possible cell selection and alignment of magnetically labeled cells.Materials and MethodsComputer simulations, in combination with experimental data, were used to optimize the design of the magnets and Ni lines to obtain the optimal magnetic configuration.ResultsA homogeneous cell distribution on the upper surface of the sample chamber was obtained with a magnet where the pole faces were tilted towards each other. The spatial distribution of magnetically aligned objects in between the Ni lines was dependent on the ratio of the diameter of the aligned object and the line spacing, which was tested with magnetically and fluorescently labeled 6 μm polystyrene beads. The best result was obtained when the line spacing was equal to or smaller than the diameter of the aligned object.ConclusionsThe magnetic gradient of the designed permanent magnet extracts magnetically labeled cells from any cell suspension to a desired plane, providing a homogeneous cell distribution. In addition, it magnetizes ferro‐magnetic Ni lines in this plane whose additional local gradient adds to the gradient of the permanent magnet. The resultant gradient aligns the magnetically labeled cells first brought to this plane. This combination makes it possible, in a single step, to extract and align cells on a surface from any cell suspension. Cytometry 47:163–172, 2002. © 2002 Wiley‐Liss, Inc.
Capacity analysis for underlaying CDMA microcell/macrocell systems
Authors: Chung Jen‐Kung , Wu Jung‐Shyr 
Published: August 2002

AbstractThe CDMA system can provide more capacity than the conventional AMPS system and the hierarchical layer of cells is required for system design in the future. However, the problem is whether the same RF channels used in a CDMA underlaying macrocell/microcell structure also obtain high capacity as in the homogeneous structure. This paper investigates the interference of uplink and downlink from both the microcell and macrocell in a hierarchical structure. Downlink power control is also considered. The results show that the capacity of microcell in a hierarchical structure is 23 per cent less than in homogeneous cells. The capacity of macrocell in a hierarchical structure decreases dramatically in proportion to the number of microcells. The capacities of the microcell and macrocell are limited in downlink, and uplink, respectively. In addition, more efforts for microcell should be made, such as more power is transmitted by microcell basestation if the same RF channel is used in a hierarchical structure. The results suggest that different RF channels are used in a two‐tier cellular environment. Copyright © 2001 John Wiley & Sons, Ltd.
Fast ping‐pong arbitration for input–output queued packet switches
Authors: Chao H. Jonathan , Lam Cheuk H. , Guo Xiaolei 
Published: August 2002

AbstractInput–output queued switches have been widely considered as the most feasible solution for large capacity packet switches and IP routers. In this paper, we propose a ping‐pong arbitration scheme (PPA) for output contention resolution in input–output queued switches. The challenge is to develop a high speed and cost‐effective arbitration scheme in order to maximize the switch throughput and delay performance for supporting multimedia services with various quality‐of‐service (QoS) requirements. The basic idea is to divide the inputs into groups and apply arbitration recursively. Our recursive arbiter is hierarchically structured, consisting of multiple small‐size arbiters at each layer. The arbitration time of an n‐input switch is proportional to log4⌈n/2⌉ when we group every two inputs or every two input groups at each layer. We present a 256×256 terabit crossbar multicast packet switch using the PPA. The design shows that our scheme can reduce the arbitration time of the 256×256 switch to 11 gates delay, demonstrating the arbitration is no longer the bottleneck limiting the switch capacity. The priority handling in arbitration is also addressed. Copyright © 2001 John Wiley & Sons, Ltd.
A comparison of congestion control and time slot algorithms in Internet transmission performance
Authors: Yang Chyan , Fu Chen‐Hua 
Published: August 2002

AbstractThe characteristics of TCP and UDP lead to different network transmission behaviours. TCP is responsive to network congestion whereas UDP is not. This paper proposes two mechanisms that operate at the source node to regulate TCP and UDP flows and provide a differential service for them. One is the congestion‐control mechanism, which uses congestion signal detected by TCP flows to regulate the flows at the source node. Another is the time‐slot mechanism, which assigns different number of time slots to flows to control their flow transmission. Based on the priority of each flow, different bandwidth proportions are allocated for each flow and differential services are provided. Simulation results show some insights of these two mechanisms. Moreover, we summarize the factors that may impact the performance of these two mechanisms. Copyright © 2001 John Wiley & Sons, Ltd.
Significance of the cytologic diagnosis of endocervical glandular involvement in high‐grade squamous intraepithelial lesions
Authors: Levine Pascale Hummel , Waisman Jerry , Mittal Khush 
Published: August 2002

AbstractThe cytologic criteria for the diagnosis of endocervical gland involvement (EGI) by high‐grade squamous intraepithelial lesions (HGSILs) have been described, and this diagnosis occasionally is made. This study evaluates the accuracy of a cytologic diagnosis compared with that of follow‐up cone biopsies. Twenty‐eight patients with Papanicolaou (Pap) smear diagnoses of HGSILs with EGI, with follow‐up cone biopsies, were identified from New York University computerized files. Results were compared with those of a control group of 28 patients showing cervical intra‐epithelial neoplasia grades II/III (CIN‐II/III), irrespective of previous Pap smear findings. On subsequent cone biopsy samples, 26 of the 28 study cases showed signs of HGSIL. Of these 26 patients, 17 (65%) showed evidence of HGSIL with EGI. Among the 28 control cases, 20 (71.4%) had EGI on the cone biopsies (P = NS). We also examined previous Pap smear findings in a control group of 42 cone biopsies with CIN‐II or CIN‐III, with or without EGI. EGI was diagnosed in previous Pap smears in 3 of the 31(10%) cases that showed signs of EGI on cone biopsies and in 2 of the 11 cases (18%) that did not evidence EGI on subsequent cone biopsies (P = NS). In our experience, the cytologic diagnosis of EGI on Pap smears did not identify a group of patients with increased frequency of EGI on subsequent cone biopsies. Diagn. Cytopathol. 2002;26:217–221. © 2002 Wiley‐Liss, Inc.