On the optimal cooling strategy for variable‐speed continuous casting

In this paper, we consider the inverse problem of determining the optimal cooling parameters for continuous casting under changing casting speed. We rely on automatic differentiation to support different search methods for the parameter values that will minimize a given cost functional, which can include a variety of criteria: surface temperature evolution and variation, interface position, full solidification point. In the direct problem we use a fixed‐domain transformation to solve the corresponding free‐boundary problem to high accuracy. Numerical experiments are provided to illustrate and support the effectiveness of the present concept. Copyright © 2001 John Wiley & Sons, Ltd.     

Exploratory research on the role of national and professionalcultures in a distributed learning project

The impact of differing national and professional cultural backgrounds is a salient issue that interacts with technological support of distributed teams. As we prepare for the world of the future it becomes imperative that we give students the experience of working in multicultural distributed teams. In order to gain experience in this area, a project between ten teams of students from the City University of Hong Kong and the Eindhoven University of Technology in The Netherlands was initiated. A variety of group support technologies, primarily Group Systems, were used to service the teams as they learned to work together. This paper documents experiences from the Hong Kong-Netherlands project. Eight out of ten student teams successfully concluded a seven-week exercise resulting in an integrated report related to software engineering. Data collected on the process are reported and discussed. Those student teams who succeeded were found to be particularly attuned and accommodating to aspects of national and professional culture     

Goodness-of-fit tests in parametric regression based on the estimation of the error distribution

Consider a heteroscedastic regression model Y=m(X)+σ(X)ε, where m(X)=E(Y|X) and σ ²(X)=Var (Y|X) are unknown, and the error ε is independent of the covariate X. We propose a new type of test statistic for testing whether the regression curve m(⋅) belongs to some parametric family of regression functions. The proposed test statistic measures the distance between the empirical distribution function of the parametric and of the nonparametric residuals. The asymptotic theory of the proposed test is developed, and the proposed testing procedure is illustrated by means of a small simulation study and the analysis of a data set.     

Second-order statistical regression and conditioning of replicate transient kinetic data

A new method has been developed to estimate physico-chemical parameters from transient kinetic data: second-order statistical regression (SOSR). It allows to account for heteroskedasticity and nonwhiteness of the noise in the time series measured. SOSR makes use of replicates to estimate the second-order statistics, i.e. the autocovariance pattern of the noise. A sample principal noise component analysis of the experimental time series allows nonlinear least-squares (NLSQ) regression of the latter. The method has been validated by regression of artificially generated experimental data and the results have been compared with those obtained with direct NLSQ regression. The SOSR has also been applied to the irreversible adsorption of oxygen on a reduced vanadia/silica catalyst and the interaction of propane with a copper/ceria catalyst, as studied with a temporal analysis of products (TAP) setup. In general, compared with those obtained with direct NLSQ regression, the parameter estimates and their confidence intervals are more accurate.     

How do people really seek information about others?: Information seeking across Internet and traditional communication channels

The present research describes the manner in which individuals use various media in the interpersonal information seeking process. Stephens' (2007) information and communication technology (ICT) succession theory was applied to an interpersonal information seeking context, and hypotheses and research questions about the channels people use to seek information about others of various relationship to the seeker were offered. Two hundred and twenty-five participants responded to a survey about this topic, and they reported a greater likelihood to seek information about less-known targets using channels where they would be unidentifiable. However, participants reported a greater likelihood to seek information about more-known targets using channels where they would be identifiable. Channels such as social networking websites were frequently reported to be useful regardless of whether the target was well known or less known. Properties of these channels and their implications for interpersonal information seeking as well as theoretical implications of these findings are discussed and directions for future research are examined.     

Antireflection coatings on semiconductor laser facets using sputtered lead silicate glass

RF-sputtered lead silicate [PbO(54 m/o)-SiO2(46 m/o)] films were used to antireflection coat InGaAsP laser facets. Modal reflectivities of1-3 times 10^{-4}were obtained.     

A new control philosophy for power electronic converters asfictitious power compensators

A new philosophy utilizing both thyristor-controlled reactive sources (TCR) and dynamic power filters (DPF) is proposed for applications in fictitious power compensation. The necessary network parameters for the control loops are calculated from digital time-domain, cross correlation signal processing techniques implemented with the aid of a microcomputer. Practical results that illustrate this control philosophy were obtained for a 15 kVA three-phase dynamic power filter     

Exact and approximate reasoning about temporal relations1

Allen gives an algebra for representing qualitative temporal information about the relationships between pairs of intervals. In this paper, we address a fundamental reasoning task that arises in applications of the algebra: Given (possibly indefinite) knowledge about the relationships between intervals, find all feasible relationships between two intervals. We call this the minimal labels problem. Finding the minimal labels can be viewed as computing the deductive consequences of our knowledge. Determining exact solutions to this problem has been shown to be (almost assuredly) intractable. Allen gives an approximation algorithm based on constraint propagation. We present new approximation algorithms; determine analytically under what conditions the algorithms are exact; and examine, through some computational experiments, the quality of the approximate solutions produced by the algorithms. We also give a simple test for predicting when the approximation algorithms will and will not produce good quality approximations. Finally, we survey three example applications of the interval algebra chosen from the literature to show where the results of this paper could be useful.