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New Criterion (new + criterion)
Selected AbstractsHierarchical Vortex Regions in Swirling FlowCOMPUTER GRAPHICS FORUM, Issue 3 2009Christoph Petz Abstract We propose a new criterion to characterize hierarchical two-dimensional vortex regions induced by swirling motion. Central to the definition are closed loops that intersect the flow field at a constant angle. The union of loops belonging to the same area of swirling motion defines a vortex region. These regions are disjunct but may be nested, thus introducing a spatial hierarchy of vortex regions. We present a parameter free algorithm for the identification of these regions. Since they are not restricted to star- or convex-shaped geometries, we are able to identify also intricate regions, e.g., of elongated vortices. Computing an integrated value for each loop and mapping these values to a vortex region, introduces new ways for visualizing or filtering the vortex regions. Exemplary, an application based on the Rankine vortex model is presented. We apply our method to several CFD datasets and compare our results to existing approaches. [source] Reducing avoidable inequalities in health: a new criterion for setting health care capitation paymentsHEALTH ECONOMICS, Issue 8 2002Katharina Hauck Abstract Traditionally, most health care systems which pretend to any sort of rationality and cost control have sought to allocate their limited funds in order to secure equal opportunity of access for equal need. The UK government is implementing a fundamental change of resource allocation philosophy towards ,contributing to the reduction of avoidable health inequalities'. The purpose of this essay is to explore some of the economic issues that arise when seeking to allocate health care resources according to the new criterion. It indicates that health inequalities might arise because of variations in the quality of health services, variations in access to those services, or variations in the way people produce health, and that the resource allocation consequences differ depending on which source is being addressed. The paper shows that an objective of reducing health inequalities is not necessarily compatible with an objective of equity of access, nor with the objective of maximising health gain. The results have profound consequences for approaches towards economic evaluation, the role of clinical guidelines and performance management, as well as for resource allocation methods. Copyright © 2002 John Wiley & Sons, Ltd. [source] Improving extreme hydrologic events forecasting using a new criterion for artificial neural network selectionHYDROLOGICAL PROCESSES, Issue 8 2001Paulin Coulibaly Abstract The issue of selecting appropriate model input parameters is addressed using a peak and low flow criterion (PLC). The optimal artificial neural network (ANN) models selected using the PLC significantly outperform those identified with the classical root-mean-square error (RMSE) or the conventional Nash,Sutcliffe coefficient (NSC) statistics. The comparative forecast results indicate that the PLC can help to design an appropriate ANN model to improve extreme hydrologic events (peak and low flow) forecast accuracy. Copyright © 2001 John Wiley & Sons, Ltd. [source] Relative uncertainty aversion and additively representable set rankingsINTERNATIONAL JOURNAL OF ECONOMIC THEORY, Issue 2 2006Walter Bossert D81 This paper proposes a definition of relative uncertainty aversion for decision models under complete uncertainty. It is shown that, for a large class of decision rules characterized by a set of plausible axioms, the new criterion yields a complete ranking of those rules with respect to the relative degree of uncertainty aversion they represent. In addition, we address a combinatorial question that arises in this context, and we examine conditions for the additive representability of our rules. [source] A new method for analysing peak broadening caused by compositional fluctuation in X-ray diffraction measurementsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2001Kiichi Nakashima A new method for analysing X-ray peak broadening caused by compositional fluctuation is proposed. The method is applicable to epitaxial layers with diamond or zinc-blende structure on (001) substrates. In the new method, a rescaling procedure with a difference variable ,A is applied to measured X-ray profiles and the dependence of the profiles on various reflection indices hkl is analysed. The theoretical formula reveals that X-ray peak profiles become independent of hkl after the rescaling. A new criterion is proposed; an experimental examination based on the criterion makes it possible simply to judge whether or not X-ray peak broadening is caused by compositional fluctuation. The method is verified experimentally and demonstrated by applying it to an InGaAs multilayer sample having artificial compositional fluctuation. [source] Phase separation of liquid-liquid two-phase flow at a T-junctionAICHE JOURNAL, Issue 1 2006L. Yang Abstract The phase separation of liquid-liquid two-phase flow at a T-junction has been studied using kerosene and deionized water as working fluids and a T-junction with a horizontal main pipe and a vertically upward side arm. Separation data are evaluated by a new criterion: separation efficiency. The results show that the T-junction is highly efficient at separating two immiscible liquids when the flows approaching the T-junction are stratified and when the fractional mass take offs close to the inlet kerosene mass fraction. A new model has been proposed for the phase separation. Comparison between the model and the experimental data shows that the data is well represented by the model. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] The adjustment of prediction intervals to account for errors in parameter estimationJOURNAL OF TIME SERIES ANALYSIS, Issue 3 2004Paul Kabaila Abstract., Standard approximate 1 , , prediction intervals (PIs) need to be adjusted to take account of the error in estimating the parameters. This adjustment may be aimed at setting the (unconditional) probability that the PI includes the value being predicted equal to 1 , ,. Alternatively, this adjustment may be aimed at setting the probability that the PI includes the value being predicted equal to 1 , ,, conditional on an appropriate statistic T. For an autoregressive process of order p, it has been suggested that T consist of the last p observations. We provide a new criterion by which both forms of adjustment can be compared on an equal footing. This new criterion of performance is the closeness of the coverage probability, conditional on all of the data, of the adjusted PI and 1 , ,. In this paper, we measure this closeness by the mean square of the difference between this conditional coverage probability and 1 , ,. We illustrate the application of this new criterion to a Gaussian zero-mean autoregressive process of order 1 and one-step-ahead prediction. For this example, this comparison shows that the adjustment which is aimed at setting the coverage probability equal to 1 , , conditional on the last observation is the better of the two adjustments. [source] Prediction of Polymer Properties in LDPE ReactorsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2005Gary J. Wells Abstract Summary: A new analysis tool is presented that uses the governing kinetic scheme to predict properties of low-density polyethylene (LDPE) such as the detailed shape of the molecular weight distribution (MWD). A model that captures mixing details of autoclave reactor operation is used to provide a new criterion for the onset of MWD shouldering. Kinetic effects are shown to govern the existence of MWD shoulders in LDPE reactors, even when operation is far from perfectly-mixed. MWD shoulders occur when the mean reaction environment has a relatively high radical concentration and has a high polymer content, and is at a low temperature. Such conditions maximize long chain formation by polymer transfer and combination-termination, while limiting chain scission. For imperfectly-mixed reactors, the blending of polymer-distributions produced in different spatial locations has a small effect on the composite MWD. However, for adiabatic LDPE autoclaves, imperfect mixing broadens the stable range of mean reactor conditions, and thereby increases the possibility for MWD shouldering. Polymer MWD produced in an LDPE autoclave reactor by various kinetic mechanisms. [source] The minimum mass ratio of W UMa-type binary systemsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007B. Arbutina ABSTRACT When the total angular momentum of a binary system Jtot=Jorb+Jspin is at a certain critical (minimum) value, a tidal instability occurs which eventually forces the stars to merge into a single, rapidly rotating object. The instability occurs when Jorb= 3Jspin, which in the case of contact binaries corresponds to a minimum mass ratio qmin, 0.071,0.078. The minimum mass ratio is obtained under the assumption that stellar radii are fixed and independent. This is not the case with contact binaries where, according to the Roche model, we have R2=R2(R1, a, q). By finding a new criterion for contact binaries, which arises from dJtot= 0, and assuming k21,k22 for the component's dimensionless gyration radii, a theoretical lower limit qmin= 0.094,0.109 for overcontact degree f= 0,1 is obtained. [source] Fire exposure of liquid-filled vesselsPROCESS SAFETY PROGRESS, Issue 1 2003Larry L. Simpson Pressure vessels in the chemical industry generally have top-mounted pressure relief valves (PRVs) sized to handle fire exposure and other possible scenarios. Designers usually assume that the fire scenario causes liquid to boil and vapor to vent, regardless of the initial liquid level. Under some circumstances, however, a high liquid level, together with thermal expansion, can result in a vessel being full of liquid when the PRV opens. If so, the initial fluid discharged through the PRV would be a two-phase gas-liquid stream. This paper analyzes non-reactive phenomena occurring during the heat-up and venting process in non-agitated liquid-filled pressure vessels. A new criterion is developed to determine if the vapor-venting sizing assumption is justified. Results from several cases show that pressures in most liquid-filled vessels sized for vapor-only flow will be below the ASME Code-allowable values during fire exposure. Hence, the common industry practice of ignoring two-phase flow when sizing fire cases is usually justified. [source] Structural stability and formability of ABO3 -type perovskite compoundsACTA CRYSTALLOGRAPHICA SECTION B, Issue 6 2007Huan Zhang On the basis of the bond-valence model (BVM) and structure-map technology, the structural stability and formability of ABO3 -type perovskite compounds were investigated in 376 ABO3 -type compounds. A new criterion of structural stability for ABO3 -type perovskite compounds has been established by the bond-valence calculated tolerance factors, which are in the range 0.822,1.139. All global instability indices for ABO3 -type perovskite compounds are found to be less than 1.2,v.u. (valence units) and increase with a decrease in oxidation state of the B cations (i.e. structural stability in the formation of an ideal cubic perovskite follows the order A+B5+O3 -type > A2+B4+O3 -type > A3+B3+O3 -type). Three new two-dimensional structure maps were constructed based on the ideal A,O and B,O bond distances derived from the BVM. These maps indicate the likelihood of particular perovskite compounds being formed. The present work enables novel perovskite and perovskite-related compounds to be explored by screening all the possible elemental combinations in future crystal engineering. [source] Model selection for generalized linear models with factor-augmented predictorsAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 3 2009Tomohiro Ando Abstract This paper considers generalized linear models in a data-rich environment in which a large number of potentially useful explanatory variables are available. In particular, it deals with the case that the sample size and the number of explanatory variables are of similar sizes. We adopt the idea that the relevant information of explanatory variables concerning the dependent variable can be represented by a small number of common factors and investigate the issue of selecting the number of common factors while taking into account the effect of estimated regressors. We develop an information criterion under model mis-specification for both the distributional and structural assumptions and show that the proposed criterion is a natural extension of the Akaike information criterion (AIC). Simulations and empirical data analysis demonstrate that the proposed new criterion outperforms the AIC and Bayesian information criterion. Copyright © 2009 John Wiley & Sons, Ltd. [source] ABSOLUTE STABILITY AND APPLICATION TO DESIGN OF OBSERVER-BASED CONTROLLER FOR NONLINEAR TIME-DELAY SYSTEMSASIAN JOURNAL OF CONTROL, Issue 3 2007Bassem Ben Hamed ABSTRACT In this paper we present a new sufficient condition for absolute stability of delay Lure system. This condition improves the one given in [1]. We use this new criterion to construct an observer-based control for a class of nonlinear time-delay systems. Some examples are given to illustrate the results of this paper. [source] Neoadjuvant chemotherapy: a new criterion for selection of candidate patients for surgery of low tumour burden metastases from malignant melanoma?BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2010T. Jouary Summary Background, Surgery of limited metastatic lesions from malignant melanoma can achieve long-term remission and better survival than chemotherapy. Existing criteria for selection of candidate patients for this surgery do not seem sufficient to avoid useless excisions. Objectives, To test use of neoadjuvant chemotherapy as a new criterion in this setting. Methods, All patients who underwent thoracic surgery for one or two lung metastases from melanoma during 1999,2007 were included in the study. Demographic and medical data were collected and analysed. Several possible prognostic factors were evaluated based on the overall survival curves. Results, Thirteen patients were included in this retrospective study. All but two patients had no evidence of disease after surgery. Ten patients received neoadjuvant chemotherapy. Six responded (absence of progression) and four had progressive disease. Response to chemotherapy and no evidence of disease after surgery were predictive of long-term survival. Conclusions, Neoadjuvant chemotherapy can be considered as a new criterion for better selection of candidate patients for lung metastasis surgical resection. This would also avoid useless surgical procedures in rapidly progressive disease and give information on the chemosensibility of the metastatic disease. This study needs further confirmation, particularly with chemotherapy regimens that have demonstrated better objective responses. [source] | |||||||||||||||||||