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Kaunas, Lithuania

It is shown that a fast reliable block Fourier algorithm for the factorization of structured matrices improves computational efficiency of known method for detecting phase synchronization in a large system of coupled oscillators, based on multivariate singular spectrum analysis. In this paper, a novel algorithm for the detection of cluster synchronization in a system of coupled oscillators is proposed. The block Toeplitz covariance matrix of the total trajectory matrix is efficiently block-diagonalized by means of the Fast Fourier Transform by embedding it first into a block circulant matrix. The synchronization structure of the underlying multivariate data set is defined based on the 2D spatiotemporal eigenvalue spectrum. The benefits of the proposed method are illustrated by simulations of the phase synchronization effects in a chain of coupled chaotic Rössler oscillators and using multichannel electroencephalogram (EEG) recordings from epilepsy patients. © JVE INTERNATIONAL LTD. JOURNAL OF VIBROENGINEERING 2014.


Streimikiene D.,Lithuanian Sports University
Renewable and Sustainable Energy Reviews | Year: 2015

Abstract Lithuania has developed several important climate change mitigation policy documents however there are no attempts in Lithuania to develop local climate change mitigation policies or to decentralize climate change mitigation policy. The aim of the paper is to analyse climate change mitigation policies in households. The paper presents the framework for the assessment of reasonably achievable GHG emission reduction (RAER) potential in households based on behavioral changes related to energy consumption. The paper presents the results of empirical application of developed framework in Lithuanian households. Community based social marketing approach was implemented and GHG emission reduction potential was assessed in focus groups of Kaunas region county during preparation of sustainable development strategy and long-term strategic development plan for Kaunas region county. © 2015 Elsevier Ltd


Pukenas K.,Lithuanian Sports University
Circuits, Systems, and Signal Processing | Year: 2014

In this paper, it is shown that the block circulant matrix decomposition technique makes the multivariate singular spectrum analysis (M-SSA) a well suited tool for detecting of changes of the correlation structure in non-stationary multivariate time series in the presence of high observational noise levels. The major drawback of M-SSA, that it operates on a large covariance matrix and becomes computationally expensive, can be avoided by reordering the Toeplitz-block covariance matrix into a block Toeplitz matrix, embedding this into a block circulant matrix and efficiently block-diagonalizing this by the means of the Fast Fourier Transform (FFT) using the well known algorithm. The overall degree of synchronization among multiple-channel signals is defined by the synchronization index (the S-estimator) of the rearranged and truncated eigenvalue spectrum. Throughout the experiment, the high capability of the proposed algorithm to detect the lag-synchronized state under the influence of strong noise is validated with simulated data - a network of time series generated by autoregressive models (AR) and a network of coupled chaotic Roessler oscillators. © 2013 Springer Science+Business Media New York.


Streimikiene D.,Lithuanian Sports University
Renewable and Sustainable Energy Reviews | Year: 2014

Environmental pressure from residential energy use is projected to significantly increase by 2030. Different environmental policy measures provide different incentives for "environmentally responsive" consumer choices and behavioural responses. There is a great energy saving potential in residential buildings of Lithuania. Compared to the other EU countries with similar climate conditions, energy consumption for residential heating is approximately 1.8 times higher in Lithuania. About 60% of Lithuanian population resides in multi-apartment buildings constructed during 1961-1990. The aim of the paper is to define the main drivers of residential energy use in Lithuania and to compare energy saving technologies in terms of energy saving potential and costs in Lithuanian residential buildings. Seeking to achieve the aim the main tasks of the paper are to analyse theoretical issues of the main drivers of residential energy use; to analyse residential energy use trends in Lithuania and to compare these trends with other EU member states; to define the main drivers of residential energy use by applying correlation analysis; to analyse policies aiming to reduce energy consumption in residential buildings and their impacts on GHG emission reduction. The comparative study of residential energy use in Lithuania and several old EU member states showed that residential energy use per capita in Lithuania is significantly lower than in old EU member states because of the lower income per capita and lower living standards. The economic and technological factors are the main driving forces of final energy consumption in all compared EU member states; however the impact of different factors varies between countries. The comparative analysis of energy saving and GHG emission reduction potential and costs in residential buildings provided by different studies showed that the most cost-effective instruments were appliance standards, energy efficiency obligations, Demand Side Management programs, public benefit charges and labelling. © 2014 Elsevier Ltd. All rights reserved.


Streimikiene D.,Lithuanian Sports University
Renewable and Sustainable Energy Reviews | Year: 2016

The paper focuses on financial support from EU Structural Funds to sustainable energy development in Baltic States. The paper aims to compare the use of Structural Funds support for sustainable energy development in Baltic States in two financing periods: 2007-2013 and 2014-2020 and to assess the impact of EU structural support in helping Baltic States to implement energy efficiency and renewable energy development targets set in EU energy policy documents. The paper analyses EU sustainable energy policy priorities and energy efficiency and renewable energy targets set for Baltic States and compares progress achieved in implementing energy efficiency and renewable energy targets in Baltic States after EU accession. The paper found that the EU Structural Funds have positively influenced the sustainable energy development in Baltic States. The major impact was related with increase in energy productivity because of energy savings achieved in refurbishment of residential buildings. Lithuania has achieved the biggest progress in energy productivity development since 2004 among Baltic States. Estonia was the only country from Baltic States which has allocated structural aid for promotion of wind energy and achieved the best results in increase of the share of renewables (mainly wind) in electricity generation. Latvia has the highest share of renewable in electricity generation structure and final energy consumption and did not provide support for renewable in 2007-2014 however support for biomass is foreseen in 2014-2020 financing period. © 2016 Elsevier Ltd. All rights reserved.

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