Performance Evaluation of Different PV-Array Configurations under Weak Light Conditions and Partial Shadings

The paper analyses empirical performance data of five commercial PV-plants in Germany. The purpose was on one side to investigate the weak light performance of the different PV-modules used. On the other hand it was to quantify and compare the shading losses of different PV-array configurations. The importance of this study relies on the fact that even if the behavior under weak light conditions or the shading losses might seem to be a relatively small percentage of the total yearly output; in projects where a performance guarantee is given, these variation can make the difference between meeting or not the conditions.When analyzing the data, a high dispersion was found. To reduce the optical losses and spectral effects, a series of data filters were applied based on the angle of incidence and absolute Air Mass. To compensate for the temperature effects and translate the values to STC (25°C), five different methods were assessed. At the end, the Procedure 2 of IEC 60891 was selected due to its relative simplicity, usage of mostly standard parameters found in datasheets, good accuracy even with missing values, and its potential to improve the results when the complete set of inputs is available.After analyzing the data, the weak light performance of the modules did not show a clear superiority of a certain technology or technology group over the others. Moreover, the uncertainties in the measurements restrictive the conclusiveness of the results.In the partial shading analysis, the landscape mounting of mc-Si PV-modules in free-field showed a significantly better performance than the portrait one. The cross-table string using CIGS modules did not proved the benefits expected and performed actually poorer than a regular one-string-per-table layout. Parallel substrings with CdTe showed a proper functioning and relatively low losses. Among the two product generations of CdTe analyzed, none showed a significantly better performance under partial shadings.

Estimation of Parameters in Random Effect Models with Incidence Matrix Uncertainty

Random effect models have been widely applied in many fields of research. However, models with uncertain design matrices for random effects have been little investigated before. In some applications with such problems, an expectation method has been used for simplicity. This method does not include the extra information of uncertainty in the design matrix is not included. The closed solution for this problem is generally difficult to attain. We therefore propose an two-step algorithm for estimating the parameters, especially the variance components in the model. The implementation is based on Monte Carlo approximation and a Newton-Raphson-based EM algorithm. As an example, a simulated genetics dataset was analyzed. The results showed that the proportion of the total variance explained by the random effects was accurately estimated, which was highly underestimated by the expectation method. By introducing heuristic search and optimization methods, the algorithm can possibly be developed to infer the 'model-based' best design matrix and the corresponding best estimates.

"Ja, denna stig är stigarnas stig" : Taoistiska influenser i Vilhelm Ekelunds verk

In this article I show how Taoist philosophy has influenced the Swedish poet, essayist and aphorist Vilhelm Ekelund. I note that the author mentions the Taoist philosophers Lao Tzu and Chuang Tzu and discusses their ideas on a couple of occasions in his later works (Atticism – Humanism, 1943; Plus salis–, 1945). Examples of such explicit influence can also be found in Ekelund’s private notebooks, posthumously published in two volumes: Hemkomst och flykt (1972) and Ur en scholaris’ verkstad (1974). I argue that Taoist philosophy implicitly influenced the Swedish author as early as the second part of the 1910’s – when he started to emphasize such principles as moderation, composure, dispassion and non-desire in his writing. I also discuss other important ideals which Ekelund shared with the Taoist philosophers, such as poverty, humility, simplicity and dishonour. Finally, I see a parallel in the anti-intellectual aspects of Taoist thinking and Ekelund’s use of the term misologi (misology), a word which often has positive connotations in his works. In Ekelund’s prose, as well as in the famous Taoist text Tao Te Ching, excessive intellectualism is frequently criticized.

Hur grafiska formgivare runt om i världen uppfattar skandinavisk grafisk design

Syftet med föreliggande studie har varit att kartlägga hur grafiska formgivare runt om i världen uppfattar skandinavisk grafisk design. 53 deltagare från industriländer deltog i studien som använde en kombination av mail-intervjuer och enkäter. Resultaten från denna studie indikerar att, oavsett kontinent, upplevs skandinavisk grafisk design som enkel och funktionell. Layouten uppfattades som rutnätsbaserad med mycket ljusrum och få grafiska element. Monokroma färger som svart, vit och grå utan gradienter och skuggor uppfattades som typiska för skandinavisk grafisk design; följt av jord- och pastellfärger. Sanserifer var mest förknippade med skandinavisk grafisk design. Motiv ansågs i denna studie att användas sparsamt, men när de används avbildar de naturen eller geometriska former. Foton och illustrationer ansågs användas ungefär lika mycket, illustrationer hade en smärre större preferens. Den upplevda påverkan av skandinavisk grafisk design varierade mellan deltagarna. Deltagarna som tyckte att påverkan var stor, ansåg att detta berodde på förespråkandet av enkelhet och funktion, sammanflätning av designområden och/eller frammaning av hållbar grafisk design. Deltagarna som ansåg att påverkan var låg, tyckte att för lite publicitet var en bidragande faktor.De flesta deltagarna i denna undersökning ansåg att skandinavisk grafisk design var enklare i jämförelse med vad de kunde se i sina hemländer. Vidare tyckte afrikanska, asiatiska och sydamerikanska deltagare  att färgerna hade lägre kroma.