Auflistung nach Autor:in "Radziszewska, Weronika"
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- KonferenzbeitragGeneration of inputs to renewable energy sources using matched-block bootstrap approach with fitness proportionate selection(Proceedings of the 27th Conference on Environmental Informatics - Informatics for Environmental Protection, Sustainable Development and Risk Management, 2013) Radziszewska, Weronika; Nahorski, ZbigniewRenewable energy sources produce clean, green energy, but their production is highly variable in time due to changeable weather conditions. Energy management systems are implemented to cope with that problem. Their proper design requires an exhaustive testing. Creation of realistic test cases requires certain amount of test data (such as wind speed and insolation). As the required amount of measured data is usually not available, they have to be generated in a way that preserves the statistical qualities of the real life phenomenon. In this article a matched-block bootstrap with fitness proportionate selection method is presented. It is a non-parametric method that samples data blocks from a real data set and concatenates them into a new data set. To model the seasonal cycles (especially visible for temperature and solar irradiance) the blocks in the bootstrap method are categorized by month, day and time, creating sets of subsequent blocks from different years with the same time and date. To maintain the coherence of data, the fitness proportionate selection methods are introduced. They provide mechanisms to choose better matching blocks with higher probability. Two fitness functions are considered for this, one using an inversion and another using a negation operation. The matched-block bootstrap methods were tested using 9 years of measurements of solar irradiance and 10 years of data of wind speed in central Poland both taken at 10-minute intervals. The generated time series have the same values for the basic statistic factors as the original data and allow for creating test sequences of an arbitrary length.
- KonferenzbeitragModeling of power consumption in a small microgrids(Proceedings of the 28th Conference on Environmental Informatics - Informatics for Environmental Protection, Sustainable Development and Risk Management, 2014) Radziszewska, Weronika; Nahorski, ZbigniewDevelopment of energy management systems and models of power grids are popular topics of many research projects. Unfortunately, quite often the behavioral tests with load data are not present. It is due to the difficulty of representing and collecting data about the power usage. To obtain such data it is required to deeply analyze operation lifecycle of certain devices and information about statistics of human behavior, as well as the patterns of people actions. Although many devices time profiles have been published, they lack characterization of variability of behavior and uncertainty. The paper presents some alternative ways to model power usage: probability profiles, rules and a mix of them. The purpose is to create a simulator for testing performance of energy management systems in a small microgrid.