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Ljubljana, Slovenia

The Jožef Stefan Institute , is the largest research institute in Slovenia. The main research areas are physics, chemistry, molecular biology, biotechnology, information technologies, reactor physics, energy and environment. At the beginning of the 2013 the Institute had 962 employees, 404 among them were Ph.D scientists.The mission of the Jožef Stefan Institute is the accumulation - and dissemination - of knowledge at the frontiers of natural science and technology to the benefit of society at large through the pursuit of education, learning, research, and development of high technology at the highest international levels of excellence.The Institute was founded by Yugoslav State Security in 1949 for atomic weapons research. Initially, the Vinča Nuclear Institute in Belgrade was established in 1948, followed by Rudjer Boskovic in Zagreb in 1949 and the Jožef Stefan Institute as an Institute for Physics within the Slovenian Academy of science and Arts. It is named after the distinguished 19th century physicist Jožef Stefan, most famous for his work on the Stefan-Boltzmann law of black-body radiation. IJS is today involved in a wide variety of fields of both scientific and economic interest. After close to 60 years of scientific achievement, the Institute has become part of the image of Slovenia.The Institute has facilities in two locations. The main facilities and the headquarters are on Jamova 39 in Ljubljana, the other location is the Institute's Reactor Center Podgorica located in Dol near Ljubljana.Over the last 60 years it has created a number of important institutions, such as the University of Nova Gorica, the Jožef Stefan International Postgraduate School and the Ljubljana Technology park. Wikipedia.

Korosec P.,Jozef Stefan Institute | Korosec P.,University of Primorska | Silc J.,Jozef Stefan Institute | Silc J.,Jozef Stefan International Postgraduate School | Filipic B.,Jozef Stefan Institute
Information Sciences | Year: 2012

Ant-Colony Optimization (ACO) is a popular swarm intelligence scheme known for its efficiency in solving combinatorial optimization problems. However, despite some extensions of this approach to continuous optimization, high-dimensional problems remain a challenge for ACO. This paper presents an ACO-based algorithm for numerical optimization capable of solving high-dimensional real-parameter optimization problems. The algorithm, called the Differential Ant-Stigmergy Algorithm (DASA), transforms a real-parameter optimization problem into a graph-search problem. The parameters' differences assigned to the graph vertices are used to navigate through the search space. We compare the algorithm results with the results of previous studies on recent benchmark functions and show that the DASA is a competitive continuous optimization algorithm that solves high-dimensional problems effectively and efficiently. © 2010 Elsevier Inc. All rights reserved. Source

Novak N.,Jozef Stefan Institute | Pirc R.,Jozef Stefan Institute | Kutnjak Z.,Jozef Stefan Institute | Kutnjak Z.,Jozef Stefan International Postgraduate School
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The prediction that the piezoelectric tensor is diverging at the critical point is verified for BaTiO3 (BTO), which is the oldest perovskite structured ferroelectric material with an extremely long and eventful research history. Here we investigate experimentally by dielectric and calorimetric measurements the existence and the position of the critical point in the electric-field-temperature (E-T) phase diagram of BTO in the vicinity of the paraelectric to ferroelectric phase transition. Measurements of the piezoelectric coefficient d31 as a function of the temperature and the electric field applied along the [001] direction show a critical enhancement of the piezoelectric response in the vicinity of the critical point, in agreement with recent calculations by Porta. The electrocaloric responsivity is found to be enhanced due to the latent heat on the paraelectric to ferroelectric transition locus below the critical point. © 2013 American Physical Society. Source

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: SFS-04-2014 | Award Amount: 5.31M | Year: 2015

LANDMARK is a pan-European multi-actor consortium of leading academic and applied research institutes, chambers of agriculture and policy makers that will develop a coherent framework for soil management aimed at sustainable food production across Europe. The LANDMARK proposal builds on the concept that soils are a finite resource that provides a range of ecosystem services known as soil functions. Functions relating to agriculture include: primary productivity, water regulation & purification, carbon-sequestration & regulation, habitat for biodiversity and nutrient provision & cycling. Trade-offs between these functions may occur: for example, management aimed at maximising primary production may inadvertently affect the water purification or habitat functions. This has led to conflicting management recommendations and policy initiatives. There is now an urgent need to develop a coherent scientific and practical framework for the sustainable management of soils. LANDMARK will uniquely respond to the breadth of this challenge by delivering (through multi-actor development): 1. LOCAL SCALE: A toolkit for farmers with cost-effective, practical measures for sustainable (and context specific) soil management. 2. REGIONAL SCALE - A blueprint for a soil monitoring scheme, using harmonised indicators: this will facilitate the assessment of soil functions for different soil types and land-uses for all major EU climatic zones. 3. EU SCALE An assessment of EU policy instruments for incentivising sustainable land management. There have been many individual research initiatives that either address the management & assessment of individual soil functions, or address multiple soil functions, but only at local scales. LANDMARK will build on these existing R&D initiatives: the consortium partners bring together a wide range of significant national and EU datasets, with the ambition of developing an interdisciplinary scientific framework for sustainable soil management.

Sluban B.,Jozef Stefan International Postgraduate School | Gamberger D.,Ruder Boskovic Institute | Lavrac N.,Jozef Stefan International Postgraduate School
Data Mining and Knowledge Discovery | Year: 2014

Noise filtering is most frequently used in data preprocessing to improve the accuracy of induced classifiers. The focus of this work is different: we aim at detecting noisy instances for improved data understanding, data cleaning and outlier identification. The paper is composed of three parts. The first part presents an ensemble-based noise ranking methodology for explicit noise and outlier identification, named Noise- Rank, which was successfully applied to a real-life medical problem as proven in domain expert evaluation. The second part is concerned with quantitative performance evaluation of noise detection algorithms on data with randomly injected noise. A methodology for visual performance evaluation of noise detection algorithms in the precision-recall space, named Viper, is presented and compared to standard evaluation practice. The third part presents the implementation of the NoiseRank and Viper methodologies in a web-based platform for composition and execution of data mining workflows. This implementation allows public accessibility of the developed approaches, repeatability and sharing of the presented experiments as well as the inclusion of web services enabling to incorporate new noise detection algorithms into the proposed noise detection and performance evaluation workflows. © 2012 The Author(s). Source

Scancar J.,Jozef Stefan Institute | Scancar J.,Jozef Stefan International Postgraduate School | Milacic R.,Jozef Stefan Institute | Milacic R.,Jozef Stefan International Postgraduate School
Journal of Analytical Atomic Spectrometry | Year: 2014

The role and impact of chromium (Cr) on the environment and living organisms depends primarily on its chemical form. High toxicity of hexavalent Cr is well documented, while trivalent Cr is an essential micronutrient. In the last decades numerous analytical procedures have been developed for the determination of Cr(vi) in different sample matrices. To obtain reliable speciation data it is important to preserve species integrity during the sample storage, pre-treatment, extraction and the determination of Cr species. Among different speciation methods combination of high performance liquid chromatography (HPLC) with atomic spectrometry techniques provides comprehensive information on the presence of Cr species in a variety of sample matrices, while hyphenation of HPLC to inductively coupled plasma mass spectrometry (ICP-MS) represents the most powerful and the most sensitive analytical tool for Cr speciation. Precise isotope ratio measurement enables the application of isotope dilution techniques for the quantification of trace amounts of individual Cr species in various environmental and biological samples. Furthermore, enriched stable isotopes can be introduced as tracers to investigations on the fate and role of Cr in the environment and living organisms or to monitor the species transformation during the analytical procedure. Despite general understanding of Cr chemistry, which is closely related to its trivalent and hexavalent oxidation states and knowledge on conditions that may influence species transformation, there are still open questions that should be addressed to obtain reliable speciation analysis data. So, this article is focused mostly to overview recent developments in methodological approaches for Cr speciation in different sample matrices by applying HPLC and spectrometric techniques. Different procedures for preparation of isotopically enriched Cr spike solutions are critically evaluated. The advantages of their use as tracers to follow and account for species transformation during sample preparation and for the quantification of Cr species by HPLC-ID-ICP-MS are discussed. The importance of the use of adequate analytical methodologies and speciation analysis in the determination of Cr(vi) is highlighted in order to avoid inadequate conclusions to be made based on wrongly applied analytical methodologies. An increasing need to develop speciation procedures for selective determination of Cr(iii) species is also emphasized. © 2014 The Royal Society of Chemistry. Source

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