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Trajectory-based Algorithm Selection with Warm-starting [article]

Anja Jankovic, Diederick Vermetten, Ana Kostovska, Jacob de Nobel, Tome Eftimov, Carola Doerr
2022 arXiv   pre-print
As suggested in Jankovic et al.  ... 
arXiv:2204.06397v1 fatcat:qf7ywzicxfg4pkn6otevzok3gu

Per-run Algorithm Selection with Warm-starting using Trajectory-based Features [article]

Ana Kostovska, Anja Jankovic, Diederick Vermetten, Jacob de Nobel, Hao Wang, Tome Eftimov, Carola Doerr
2022 arXiv   pre-print
Per-instance algorithm selection seeks to recommend, for a given problem instance and a given performance criterion, one or several suitable algorithms that are expected to perform well for the particular setting. The selection is classically done offline, using openly available information about the problem instance or features that are extracted from the instance during a dedicated feature extraction step. This ignores valuable information that the algorithms accumulate during the
more » ... process. In this work, we propose an alternative, online algorithm selection scheme which we coin per-run algorithm selection. In our approach, we start the optimization with a default algorithm, and, after a certain number of iterations, extract instance features from the observed trajectory of this initial optimizer to determine whether to switch to another optimizer. We test this approach using the CMA-ES as the default solver, and a portfolio of six different optimizers as potential algorithms to switch to. In contrast to other recent work on online per-run algorithm selection, we warm-start the second optimizer using information accumulated during the first optimization phase. We show that our approach outperforms static per-instance algorithm selection. We also compare two different feature extraction principles, based on exploratory landscape analysis and time series analysis of the internal state variables of the CMA-ES, respectively. We show that a combination of both feature sets provides the most accurate recommendations for our test cases, taken from the BBOB function suite from the COCO platform and the YABBOB suite from the Nevergrad platform.
arXiv:2204.09483v1 fatcat:rpxh5ibl6rebdngmdz7tmz6lme

Microbiological analysis of the mummy of St. Marcian

Jasenka Skrlin, Lovro Kavur, Emilija Missoni Mlinarić, Ivor Janković, Anja Petaros, Boris Brkljacić, Mislav Cavka
2011 Collegium Antropologicum  
The paper provides the results of the microbiological analysis of samples taken from the mummified remains of St. Marcian. Microorganisms found belong to bacteria and fungi of the genera Aspergillus, Bacillus, Penicillium, Sarcina, and Shewanella which are all apart of the common air, soil, and human microbial flora and therefore present no health hazard.
pmid:22053579 fatcat:ma5ozc5rhvhdldqgez36uekd5a

A probable case of Hand-Schueller-Christian's disease in an Egyptian mummy revealed by CT and MR investigation of a dry mummy

Mislav Cavka, Anja Petaros, Gordana Ivanac, Lejla Aganović, Ivor Janković, Gert Reiter, Peter Speier, Sonja Nielles-Vallespin, Boris Brkljacić
2012 Collegium Antropologicum  
The challenging mission of paleopathologists is to be capable to diagnose a disease just on the basis of limited information gained by means of one or more paleodiagnostic techniques. In this study a radiologic, anthropologic and paleopathologic analysis of an ancient Egyptian mummy through X-rays, CT and MR was conducted. An Ancient Egyptian mummy ("Mistress of the house", Archeological Museum, Zagreb, Croatia) underwent digital radiography, computed tomography and magnetic resonance imaging
more » ... ploying 3-dimensional ultra-short-echo time (UTE) sequence, that allows to image ancient dry tissue. Morphological observations on the skull and pelvis, the stages of epiphyseal union and dental wear indicated that the remains are those of a young adult male. Multiple osseous lytic lesions were observed throughout the spine as well as on the frontal, parietal, and occipital bone, orbital wall and the sella turcica of the sphenoid. Considering the sex and age of the individual and the features of the lesions, the authors propose the diagnosis of Hand-Schueller-Christian's disease. This is the first study to have effectively used MR images in the differential diagnosis of a disease. It also confirmed the CT value in revealing central nervous system involvement just by detecting skeletal lesions. Although the mummy was previously dated to 3rd century B.C. based on the properties of the sarcophagi, the sex of the mummy suggests that it was most probably transferred into these sarcophagi in later times. The mummification techniques used and radiometric data (C14) dated it to 900-790. B.C.
pmid:22816232 fatcat:phgup74v6fhhzj5qbgkb26wpxe

The use of paleo-imaging and microbiological testing in the analysis of antique cultural material: multislice tomography, and microbial analysis of the Trogir Cathedral cope hood depicting St. Martin and a beggar

Mislav Cavka, Anja Petaros, Lovro Kavur, Jasenka Skrlin, Emilija Mlinaric Missoni, Ivor Jankovic, Boris Brkljacic
2013 Acta Medico-Historica Adriatica  
Paleoradiology is the study of biological and other materials from archeological settings through the use of various medical imaging techniques. Although it is most often used in the scientific study of ancient human remains, it can also be used to study metals, ceramics, paper, and clothes. The aim of this study was to test two paleoimaging techniques (MSCT and mammography) in the analysis of an important Croatian liturgical vestment: the hood of a bishop's cope from St. Lawrence's Treasury in
more » ... Trogir depicting St. Martin and a beggar. To ensure a safe environment for scientists participating in the analysis, a preliminary microbiological analysis was performed, which contributed to the database of microbiological flora found on Croatian archeological remains and relics studied to date. Due to a great amount of metal filaments, the paleoradiological analysis did not produce satisfactory results. However, a digitally enhanced image clearly showed fine metal embroidery of the hood that was not so easily perceived by naked eye. This article argues in favor of expanding paleoradiological studies on materials other than human remains and also of publishing unsatisfactory results, as important lessons for future development of techniques and methods to analyze ancient remains and seek answers about human historical and cultural heritage.
pmid:23883082 fatcat:lpsjjx46xjfplcacn2ehkjxttq

Personalizing Performance Regression Models to Black-Box Optimization Problems [article]

Tome Eftimov, Anja Jankovic, Gorjan Popovski, Carola Doerr, Peter Korošec
2021 pre-print
Accurately predicting the performance of different optimization algorithms for previously unseen problem instances is crucial for high-performing algorithm selection and configuration techniques. In the context of numerical optimization, supervised regression approaches built on top of exploratory landscape analysis are becoming very popular. From the point of view of Machine Learning (ML), however, the approaches are often rather naive, using default regression or classification techniques
more » ... out proper investigation of the suitability of the ML tools. With this work, we bring to the attention of our community the possibility to personalize regression models to specific types of optimization problems. Instead of aiming for a single model that works well across a whole set of possibly diverse problems, our personalized regression approach acknowledges that different models may suite different types of problems. Going one step further, we also investigate the impact of selecting not a single regression model per problem, but personalized ensembles. We test our approach on predicting the performance of numerical optimization heuristics on the BBOB benchmark collection.
doi:10.1145/3449639.3459407 arXiv:2104.10999v1 fatcat:tz4wsn5yfzgy3b5ocjrp2niwum

Landscape-Aware Fixed-Budget Performance Regression and Algorithm Selection for Modular CMA-ES Variants [article]

Anja Jankovic, Carola Doerr
2020 pre-print
Automated algorithm selection promises to support the user in the decisive task of selecting a most suitable algorithm for a given problem. A common component of these machine-trained techniques are regression models which predict the performance of a given algorithm on a previously unseen problem instance. In the context of numerical black-box optimization, such regression models typically build on exploratory landscape analysis (ELA), which quantifies several characteristics of the problem.
more » ... ese measures can be used to train a supervised performance regression model. First steps towards ELA-based performance regression have been made in the context of a fixed-target setting. In many applications, however, the user needs to select an algorithm that performs best within a given budget of function evaluations. Adopting this fixed-budget setting, we demonstrate that it is possible to achieve high-quality performance predictions with off-the-shelf supervised learning approaches, by suitably combining two differently trained regression models. We test this approach on a very challenging problem: algorithm selection on a portfolio of very similar algorithms, which we choose from the family of modular CMA-ES algorithms.
doi:10.1145/3377930.3390183 arXiv:2006.09855v1 fatcat:5uyyawrdbrfgzddyryfza3wp2y

The Impact of Hyper-Parameter Tuning for Landscape-Aware Performance Regression and Algorithm Selection [article]

Anja Jankovic, Gorjan Popovski, Tome Eftimov, Carola Doerr
2021 pre-print
Automated algorithm selection and configuration methods that build on exploratory landscape analysis (ELA) are becoming very popular in Evolutionary Computation. However, despite a significantly growing number of applications, the underlying machine learning models are often chosen in an ad-hoc manner. We show in this work that three classical regression methods are able to achieve meaningful results for ELA-based algorithm selection. For those three models -- random forests, decision trees,
more » ... bagging decision trees -- the quality of the regression models is highly impacted by the chosen hyper-parameters. This has significant effects also on the quality of the algorithm selectors that are built on top of these regressions. By comparing a total number of 30 different models, each coupled with 2 complementary regression strategies, we derive guidelines for the tuning of the regression models and provide general recommendations for a more systematic use of classical machine learning models in landscape-aware algorithm selection. We point out that a choice of the machine learning model merits to be carefully undertaken and further investigated.
doi:10.1145/3449639.3459406 arXiv:2104.09272v1 fatcat:rewlb7xqhjakzgquwoxknhrpqi

System architecture design

Claudia Eckert, Marija Jankovic
2016 Artificial intelligence for engineering design, analysis and manufacturing  
The impact of the set-based design on system architecture design has been investigated by Anja Schultze in "Developing Products With Set-Based Design: How to Set Up an Idea Portfolio and a Team Organization  ...  Marija Jankovic and Claudia Eckert are exploring these factors in their article "Architecture Decisions in Different Product Classes for Complex Products," which was reviewed independently of this Special  ...  Jankovic 216  ... 
doi:10.1017/s0890060416000202 fatcat:tnp7nxuavvc45dtnjimdfrxrry


Ivana Binic, Milenko Stanojevic, Aleksandar Jankovic
2005 Acta Medica Medianae  
Vrednosti procentualnog pobolj{anja skoreva prikazani su na Grafikonu 2.  ...  Procenat pobolj{anja skora simptoma posle sedam dana le~enja iznosio je 21,05 sa najve}om vredno{}u od 92,10 sedme nedelje, odnosno na kraju le~enja, i procentom pobolj{anja ukupnog skora, koji posle 7  ...  Literatura ELEKTROIONOTHERAPY ‡ A NEW PATTERN OF VENOUS ULCERS HEALING Aleksandar Jankovic, Milenko Stanojevic and Ivana Binic Venous ulcers are frequent, chronic disease which requires the constant  ... 
doaj:b60776adebae41c49a955a6d3ef60656 fatcat:3yyjnsyr5na6bemlmgyt54cina

User Experience and Customer Experience as a Solution for Gaining Competitive Advantages of the Company

Anja Janković, Nataša Tomić, Nenad Simeunović, Slavko Rakić, Darko Stefanović, Teodora Lolić
2019 Proceedings of the 24th International Scientific Conference Strategic Management and Decision Support Systems in Strategic Management   unpublished
The user experience becomes a very important factor when companies want to be better than competition and keep customer loyalty. This paper analyzes the relation between the User Experience (UX) and the Customer Experience (CX) in terms of the impact they have on the overall satisfaction of users. This study aims to determine which of the two experiences is more relevant and has more impact on the user's satisfaction with the company. UX and CX are very similar concepts, but the terms are not
more » ... terchangeable. Every company has the task of satisfying the needs of the users and providing more than user expectations. The purpose of this paper is to show how and how much UX affects the CX, and inversely. This study analyze their significance to exploit the user experience for receive competitive advantages.
doi:10.46541/978-86-7233-380-0_24 fatcat:s6c2ik3h4bh2zpe6h66iersmq4


Sandra Janković
2005 Tourism and hospitality management  
Tablica 3 Kapacitet hotela REZU L T A T O P E R A T IV N A O D J E L J E N J A S M J E Š T A J ZAKLJUČAK I PRIJEDLOZI ZA DALJNJA ISTRAŽIV ANJA Dizajn, kompleksnost i detaljnost obračuna troškova procesa  ...  Janković: MODEL UVOĐENJA OBRAČUNA TROŠKOVA PROCESA U HOTELSKU INDUSTRIJU procesa.  ... 
doi:10.20867/thm.11.1.18 fatcat:i7cvdsko6ba7dnmlslcfestwfi


M. Janković, A. Tanasijević, R. Filipović, M. Perušić
2014 Journal of Engineering & Processing Management  
Janković, A.Tanasijević, R. Filipović, M. Perušić  ...  Janković, A. Tanasijević, R. Filipović, M. Perušić Slika1.  ... 
doaj:e49e883259f942f382e83d920802c493 fatcat:gge5g25dgjha7kghiofrnjj4ty


Vladmila Bojanic, Todorka Savic, Boris Djindjic, Ruzica Jankovic
2004 Acta Medica Medianae  
{anja.  ...  Klini~ki se manifestuje u vidu pove}anja kreatin fosfoki naze i mialgije pra}ene slabo{}u mi{i}a.  ... 
doaj:30c08d746ec0409085d6c436761f44ad fatcat:5vj4hay3ejfztjq54r42uyjj4u

Characteristics of Powershift gear of agricultural tractors
Karakteristike Powershift menjača kod poljorivrednih traktora

Zlata Bracanović, Velimir Petrović, Branka Grozdanić, Đuro Borak
2019 Poljoprivredna tehnika  
LITERATURA [1] Izveštaj Projekta TR-35039.(2016).Ministarstva prosvete, nauke i tehnološkog razvoja Srbije. [2] Janković, A., Radonjić, D., Glišović, J., Radonjić, R. (2011).  ...  Ako se veza uspostavi preko Datatronik sistema, može se podesiti i vreme obavlјanja određene funkcije 16.  ... 
doi:10.5937/poljteh1904073b fatcat:i5d4kuyjebgdrj2dtvgn7tijxq
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