A Tower-Shadow Model for Wind Turbines Using a Wavelet-Prony Method

The increasing penetration of wind generation on the Island of Ireland has been accompanied by close investigation of low-frequency pulsations contained within active power flow. A primary concern is excitation of low-frequency oscillation modes already present on the system, particularly the 0.75 Hz mode as a consequence of interconnection between the Northern and Southern power system networks. In order to determine whether the prevalence of wind generation has a negative effect (excites modes) or positive impact (damping of modes) on the power system, oscillations must be measured and characterised. Using time – frequency methods, this paper presents work that has been conducted to extract features from low-frequency active power pulsations to determine the composition of oscillatory modes which may impact on dynamic stability. The paper proposes a combined wavelet-Prony method to extract modal components and determine damping factors. The method is exemplified using real data obtained from wind farm measurements.

On being a good nurse: reflections on the past and preparing for the future

On being a good nurse: reflections on the past and preparing for the future. The objectives of this paper include reflecting on the attributes of the ‘good’ nurse in the past, outlining thematically the essential attributes (virtues) required by the ‘good’ nurse today and presenting an original four- point framework for ethics in practice. While there is no doubt that nurses in the past were highly professional, the culture within which they practiced tended to stifle the emergence of autonomy, assertiveness, advocacy and accountability. An original table of contemporary attributes, which is congruent with a neo Aristotelian virtue ethical approach, is arranged in themes of Intellectual and Practical Attributes, Dispositional Attributes and Moral Attributes. A framework for professional practice, the ‘Four As’ is then extrapolated from these themes. These four key professional attributes, autonomy, advocacy, accountability and assertiveness, along with the virtues listed in the themes, exemplify the ‘good’ nurse and are identified as the linchpins of modern professional ethics and good conduct.

The good, the bad and the 'not so bad': reflecting on moral appraisal in practice

The aim of this paper is to facilitate reflection on the moral merit of practitioners in various contexts. Insight is gained from Aristotelian and Kantian accounts of moral character and an original framework for reflection is presented as an adjunct to ethical theory and principles considered when appraising others. In relation to states of character there is an irreconcilable difference between Kantian (deontic) and Aristotelian (aretaic) conceptions of the nature of full virtue (excellence of character), but at the same time it can be argued that in relation to practice their approaches complement each other. It is also argued that in relation to caring for the vulnerable, Aristotle’s conception of full virtue is more compelling than Kant’s. On the other hand, Kant’s notion of self - serving action is important in nursing and it therefore needs to be considered when reflecting on professional conduct. The conclusion reached is that Aristotelian and Kantian accounts of character appraisal should be used in a combined approach to moral appraisal. This approach draws on the accounts of both philosophers and offers valuable insight into moral character, professional conduct and, in a more formal setting, fitness to practise.

Are Good Industrial Relations Good for the Economy?

Recent US microeconomic analysis indicates that good industrial relations might improve firm performance. Of late, it has also been claimed that the benefits of industrial relations quality - proxied inversely by a strikes variable - could also extend to the macroeconomy. Using cross-country data, we find that, independent of other labor market institutions, a lower strike volume is associated with lower unemployment. Although there is a separate line of causation running from unemployment to strikes, our analysis suggests that this is not dominant. That said, support for the notion that macro performance owes something to good industrial relations is, however, weakened once we formally control for strike endogeneity.

Panel Stationarity Test with Structural Breaks

In this paper, we extend the heterogeneous panel data stationarity test of Hadri [Econometrics Journal, Vol. 3 (2000) pp. 148–161] to the cases where breaks are taken into account. Four models with different patterns of breaks under the null hypothesis are specified. Two of the models have been already proposed by Carrion-i-Silvestre et al.[Econometrics Journal,Vol. 8 (2005) pp. 159–175]. The moments of the statistics corresponding to the four models are derived in closed form via characteristic functions.We also provide the exact moments of a modified statistic that do not asymptotically depend on the location of the break point under the null hypothesis. The cases where the break point is unknown are also considered. For the model with breaks in the level and no time trend and for the model with breaks in the level and in the time trend, Carrion-i-Silvestre et al. [Econometrics Journal, Vol. 8 (2005) pp. 159–175]showed that the number of breaks and their positions may be allowed to differ acrossindividuals for cases with known and unknown breaks. Their results can easily be extended to the proposed modified statistic. The asymptotic distributions of all the statistics proposed are derived under the null hypothesis and are shown to be normally distributed. We show by simulations that our suggested tests have in general good performance in finite samples except the modified test. In an empirical application to the consumer prices of 22 OECD countries during the period from 1953 to 2003, we found evidence of stationarity once a structural break and cross-sectional dependence are accommodated.