CONTENTS & ABSTRACTSIn English. Summaries in EstonianProceedings of theEstonian Academy of Sciences.Engineering Volume 9 No. 1March 2003 Exploringirregular vibrations and chaos by the wavelet method;3–24Ülo LepikAbstract. The paper cosiders possibilities of exploring nonlinearstructural vibrations and detecting chaos by the wavelet method. The signal isdecomposed into several lower resolution components. Some numerical quantitiesfor characterizing the signal (wavelet energy distribution, Shannon andthreshold entropy, similarity index, self-similarity) are introduced. Noisysystems are discussed. An example, in which the noise transfers chaotic motionto regular vibrations, is described. The wavelet packet method is applied; itis shown that such an approach allows to decrease the width of the frequencybands and gives the possibility to distinguish chaotic vibrations from randommotion.Key words: non-linearvibrations, chaos, wavelet method, entropy, noisy systems.A parametric optimization technique for model-predictivecontrol simulation; 25–33Ingmar RandveeAbstract. A parametrization technique, whichhas been introduced in the 1980s in the context of multilevel systems, isrevisited. It is shown that a version of this optimization technique (whichskips the introduction of co-states and the solution of the two-point boundaryvalue problem) may be applicable in the numerical simulation of one-step aheadunconstrained model-predictive control strategies and other suboptimalreal-time dynamic systems that use predicted closed-loop system trajectories.The representation is given in discrete-time setting using state-space models.Key words: predictivecontrol, parametric optimization.On thecrawl space moisture control in buildings; 34–58Miimu Airaksinen, JarekKurnitski, and Olli SeppänenAbstract. This study considers transient effects of the moisturecapacity and other properties of ground covers and base floor on relativehumidity in cold-climate outdoor-air-ventilated crawl spaces. The objectives ofthe study were to find out how relative humidity can be reduced by optimalselection of ground covers and air change rates, and to evaluate theacceptability of achieved moisture conditions by means of mould growthanalyses. Two buildings, one with a relatively warm and another with arelatively cold crawl space, were studied with the resistance-capacity networkmodel including the heat and moisture transfer in crawl spaces. Thermal andmoisture buffering effects of various ground covers and air change rates weresimulated. In a relatively warm crawl space the moisture problems were easy toavoid – all ground covers gave clearly acceptable conditions at an air changerate of 0.5–2.0 ach. In the cold crawl space, the moisture conditions weremuch more critical. The acceptability of conditions was evaluated bycalculating the mould growth index. To achieve acceptable moisture conditions,15–30 cm lightweight expanded clay aggregate or 5–10 cm expandedpolystyrene ground cover must be used. An air change rate of 0.5–1.0 achprovided the lowest relative humidity conditions during the heating season, andin the summer it was necessary to use an air change rate of 2.0–5.0 ach towarm up the crawl space. In critical conditions, thermal insulation and moisturecapacity proved to be important properties of the ground cover allowing toachieve acceptable conditions.Key words: crawl space, air change rate, relative humidity, mould growth.Thermalperformance of typical residental buildings; 59–66Teet-Andrus Kõiv andKadi KusnetsovAbstract. This paper describes indoor temperature forming in typicalpanel apartment buildings. Using average free heat gain data, balancetemperatures in different months of the heating period are determined. Based onaverage external temperatures of the years 1971–2000 in Tallinn and balancetemperatures, the number of corrected heating degree-days in different monthsis obtained.Key words: free heat gains, heat losses, balance temperature, corrected heatingdegree-days. Instructionsto authors; 67–69CopyrightTransfer Agreement; 70
