To assess the quality of the fit in a multiple linear regression, the coefficient of determination or
R
2 is a very simple tool, yet the most used by practitioners. Indeed, it is reported in most ...statistical analyzes, and although it is not recommended as a final model selection tool, it provides an indication of the suitability of the chosen explanatory variables in predicting the response. In the classical setting, it is well known that the least-squares fit and coefficient of determination can be arbitrary and/or misleading in the presence of a single outlier. In many applied settings, the assumption of normality of the errors and the absence of outliers are difficult to establish. In these cases, robust procedures for estimation and inference in linear regression are available and provide a suitable alternative.
In this paper we present a companion robust coefficient of determination that has several desirable properties not shared by others. It is robust to deviations from the specified regression model (like the presence of outliers), it is efficient if the errors are normally distributed, it does not make any assumption on the distribution of the explanatory variables (and therefore no assumption on the unconditional distribution of the responses). We also show that it is a consistent estimator of the population coefficient of determination. A simulation study and two real datasets support the appropriateness of this estimator, compared with classical (least-squares) and several previously proposed robust
R
2, even for small sample sizes.
The innovation policy of the new German government is at the threshold between the traditional and the transformative. In addition to company-oriented measures, current innovation policy in Germany ...is characterised above all by its orientation toward benefits for society as a whole. This represents an incremental development compared to the previous government. The focus is on reorienting knowledge transfer for societal transitions. Against this background, the innovation policy outlined in the coalition agreement contains traditional and transformative elements. Effects of the innovation policy arise in the areas of openness to technology, legitimacy of policy measures and participation. Die im Koalitionsvertrag skizzierte Innovationspolitik stellt einen Ubergang zwischen traditioneller und transformativer Politik dar. Die aktuelle deutsche Innovationspolitik zeichnet sich, neben unternehmenszentrierten Massnahmen, vor allem durch die Ausrichtung auf gesamtgesellschaftliche Ziele aus. Dies bedeutet eine graduelle Weiterentwicklung im Vergleich zur Vorgangerregierung. Im Zentrum steht die Reorganisation von Wissenstransfer fur gesellschaftliche Transformationen. Auswirkungen der Innovationspolitik der Ampelkoalition ergeben sich in den Bereichen der Technologieoffenheit, der Legitimation der Politikmassnahmen und der Partizipation bei Anderung der Zielsetzungen.
•Hydrogen concentration effects on oxy-colorless distributed combustion.•Mitigation of flashback was achieved under distributed condition.•Flame stability enhancement provided for high hydrogen ...content fuel.•Demonstrated low CO under favorable distributed condition.
Oxy-colorless distributed combustion is a novel combustion technique to achieve more uniform and controlled thermal field, enhance flame stability, and reduce emissions including combustion noise. Colorless distributed combustion (CDC) conditions was achieved through controlled entrainment of hot reactive gaseous species. This allowed for reduction of oxygen concentration to provide improved mixture preparation for distributed combustion with the reaction zone distributed across the entire volume of the combustor. In this study, oxy-colorless distributed combustion was examined for fuel flexibility using different mixtures of methane and hydrogen diluted with 10% each of N2 and CO2 to represent low heating value fuels. The oxidizer used was an O2-CO2 mixture that eliminated the formation of NOx from the combustor. The evolved OH* chemiluminescence signatures were recorded for various hydrogen concentrations in the fuel at equivalence ratios in the range of 0.6–0.9 under distributed combustion condition. At Φ = 0.9, transition to CDC initiated at oxygen concentrations of 17%, 19% and 21% for fuels having a hydrogen concentration of 60%, 50% and 40% (on volume basis), respectively. Differences in transition point were attributed to higher flame speed associated with more hydrogen in the fuel. Gaseous fuel having high hydrogen concentration provided more distributed OH* flame structures at lower oxygen concentration while the flame stability enhanced at higher oxygen concentration. Oxy-colorless conditions provided only 10–30 ppm CO even at high oxygen concentration and high (0.9) equivalence ratio. The results showed fuel flexibility from different heating value gaseous fuels having high hydrogen content. The results provided very low CO emission and enhanced flame stability under oxy-colorless distributed combustion for the low heating value fuels using O2-CO2 mixture as the oxidant.
Regional climate models (RCMs) are a widely used tool to describe regional-scale climate variability and change. However, the added value provided by such models is not well explored so far, and ...claims have been made that RCMs have little utility. Here, it is demonstrated that RCMs are indeed returning significant added value. Employing appropriate spatial filters, the scale-dependent skill of a state-of-the-art RCM (with and without nudging of large scales) is examined by comparing its skill with that of the global reanalyses driving the RCM. This skill is measured by pattern correlation coefficients of the global reanalyses or the RCM simulation and, as a reference, of an operational regional weather analysis. For the spatially smooth variable air pressure the RCM improves this aspect of the simulation for the medium scales if the RCM is driven with large-scale constraints, but not for the large scales. For the regionally more structured quantity near-surface temperature the added value is more obvious. The simulation of medium-scale 2-m temperature anomaly fields amounts to an increase of the mean pattern correlation coefficient up to 30%. PUBLICATION ABSTRACT
Abstract The innovation policy of the new German government is at the threshold between the traditional and the transformative. In addition to company-oriented measures, current innovation policy in ...Germany is characterised above all by its orientation toward benefits for society as a whole. This represents an incremental development compared to the previous government. The focus is on reorienting knowledge transfer for societal transitions. Against this background, the innovation policy outlined in the coalition agreement contains traditional and transformative elements. Effects of the innovation policy arise in the areas of openness to technology, legitimacy of policy measures and participation.
In polymer electrolyte membrane fuel cells, power losses associated with slow reaction kinetics and mass-transport limits can be strongly influenced by convective flow characteristics. Specifically, ...convection in the form of channel bypass may be utilized to simultaneously increase reactant concentration and reduce product concentration in the catalyst layer, thus reducing the activation and mass-transport overpotentials. An analytical model is developed here to predict the flow pattern and pressure field in general single-serpentine flow field geometries. The model predicts that a significant portion of the total flow through the fuel cell can occur as in-plane convective flow through the gas diffusion layer under realistic operating conditions. Further, by comparing the in-plane rates of diffusive and convective transport it is found that the dominant mechanism depends on the geometric and material parameters of the flow field. In particular, it is found that the relative influence of convection depends highly on in-plane permeability of the gas diffusion layer and channel length, and is relatively independent of gas diffusion layer thickness. By designing fuel cells to utilize enhanced in-plane convection, it is suggested that losses associated with low oxygen content as well as liquid water buildup in the catalyst layer can be reduced.
FESER E. J. and BERGMAN E. M. (2000) National industry cluster templates: a framework for applied regional cluster analysis, Reg. Studies 34, 1-19. A growing number of cities, states and regions in ...Europe, North America and elsewhere are designing development strategies around strategic clusters of industries. In many cases, a lack of data on local and interregional industrial linkages, shared business institutions, channels of technology and knowledge transfer, and other dimensions of the cluster concept means that relatively simple measures (location quotients, industry size) are often used to initially detect clusters in subnational regions. In this paper, we suggest a means of using available information on national interindustry linkages to identify potential clusters in subnational areas. Specifically, we derive a set of 23 US manufacturing clusters and employ them as templates in an illustrative analysis of the manufacturing sector in a single US state. The template clusters help detect gaps and specializations in extended product chains and therefore constitute a useful first step in more comprehensive examinations of local cluster patterns.
FESER E. J. et BERGMAN E. M. (2000) Des gabarits de grappes d'industries d'envergure nationale: un cadre pour l'analyse appliquée des grappes à l'échelon régional, Reg. Studies 34, 1-19. De plus en plus nombreux sont les villes, les états et les régions en Europe, en Amérique du Nord et ailleurs qui mettent au point des stratégies de développement visant des grappes d'industries clé. Dans beaucoup des cas, le manque de données sur le maillage industriel local et interrégional, le partenariat commercial, les canaux de transfert de la technologie et de l'apprentissage, et autres dimensions de la notion de grappes, signifient que des mesures relativement simples (quotient de localisation, taille de l'industrie) se voient employer souvent afin de découvrir dans un premier temps des grappes sur le plan régional. Cet article avance un moyen d'employer les données disponibles sur le maillage intersectoriel national pour identifier des grappes éventuelles sur le plan régional. Plus particulièrement, on emploie un ensemble de vingt-trois grappes industrielles aux Etats-Unis comme gabarits pour analyser à titre d'exemple le secteur industriel dans un seul état aux Etats-Unis. Les gabarits aident à découvrir les créneaux et les spécialisations des chaînes de produits élargies et constituent ainsi une première démarche dans l'examen plus approfondi de la distribution locale des grappes.
FESER E. J. und BERGMAN E. M. (2000) Schablonen für Kluster der Landesindustrie: ein Grundgerüst für angewandte Regionalklusteranalyse, Reg. Studies 34, 1-19. Eine wachsende Anzahl von Städten, Regionen und Staaten in Europa, Nordamerika und anderen Orten entwerfen Entwicklungsstrategien, die strategische Kluster von Industrien zum Mittelpunkt haben. In vielen Fällen führt Mangel an Information über örtliche und unterregionale Industrieverbindungen, über gemeinsam benutzte geschäftliche Institutionen, Wege der Technologie-und Wissensvermittlung sowie anderer Dimensionen des Klusterkonzepts dazu, daß relativ einfache Maßnahmen (Standortquotienten, Industriegröße) benutzt werden, um anfangs Kluster auf teilstaatlicher Ebene überhaupt zu entdecken. In diesem Aufsatz wird ein Mittel zur Nutzung vorhandener Information betreff staatlicher. Interindustrieller Verknüpfungen vorgeschlagen, um potentielle Kluster in staatlichen Teilgebieten zu identifizieren. Um präzise zu sein: es wird ein Satz von 23 Klustern der herstellenden Industrie in den Vereinigten Staaten erstellt, und als Schablone in einer illustrativen Analyse des Sektors der herstellenden Industrie in nur einem Staat der Vereinigten Staaten angewandt. Die Schablonenkluster tragen dazu bei, Lücken und Spezialisierung in erweiterten Produktketten ausfindig zu machen, und stellen deshalb einen nützlichen ersten Schritt bei der umfassenderen Untersuchung örtlicher Klustermuster dar.
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