Primitive Central Idempotents of Rational Group Algebras

We give a description of the primitive central idempotents of the rational group algebra QG of a finite group G. Such a description is already investigated by Jespers, Olteanu and del R\'io, but some unknown scalars are involved. Our description also gives answers to their questions

Overview of methods to analyse dynamic data

This book gives an overview of existing data analysis methods to analyse the dynamic data obtained from full scale testing, with their advantages and drawbacks. The overview of full scale testing and dynamic data analysis is limited to energy performance characterization of either building components or whole buildings. The methods range from averaging and regression methods to dynamic approaches based on system identification techniques. These methods are discussed in relation to their application in following in situ measurements: -measurement of thermal transmittance of building components based on heat flux meters; -measurement of thermal and solar transmittance of building components tested in outdoor calorimetric test cells; -measurement of heat transfer coefficient and solar aperture of whole buildings based on co-heating or transient heating tests; -characterisation of the energy performance of whole buildings based on energy use monitoring

In-situ U-value-measurements of wood frame roofs: analysis of deviations between measured and design performance

The hygrothermal performance of various lightweight sloped roof designs was monitored in the KULeuven VLIET testbuilding for 2 years (Janssens et al. 1998). One of the aims of the investigation was to evaluate whether the design U-value of 0.18 W/m²K was effectively met in practice. For this reason 3 heatflux transducers were installed at the inside surface of each component together with a number of thermocouples at the surfaces of the composing material layers. The U-value was derived from the measurements by averageing the collected data on a daily basis. The observed deviations between the measured and design U-values are analysed and explained by quantifying the inconsistencies between the assumptions for the calculation of the design thermal performance and the conditions of the in-situ measurement. The following causes of deviations are analysed in detail, and related to the position of the heat flux transducer on the test components: (1) heat transport affected by wind-washing in the roofs, (2) 2-dimensional heat flow through framing elements in the roof

De Jure Rigidity

The rigid designation of proper names and natural kind terms is the most well-known doctrine of Kripke’s Naming and Necessity (1981). On the basis of rigidity, Kripke has shown that proper names and natural kind terms do not refer via a description as argued by descriptivists. In response to Kripke several people have argued that all general terms could be interpreted rigidly, which would make the notion of rigidity trivial. This leads to the ‘rigidity problem’: the notion of rigidity cannot be used to argue against descriptivism anymore. I will show that the rigidity problem appears on a larger scale: firstly, because it appears independently of the trivialisation problem, secondly, because it appears for descriptions acting like singular terms as well. I will argue, however, that proper names and natural kind terms differ in an important manner from rigid descriptions. While the first are de jure rigid, the latter are de facto rigid. I will show that the rigidity problem indeed appears for de facto rigidity, but not for de jure rigidity, with the result that Kripke’s argument against descriptivism can withstand