1. Parkinson’s disease non-motor subtypes classification in a group of Slovenian patients : actuarial vs. data-driven approachTimotej Petrijan, Jan Zmazek, Marija Menih, 2023, izvirni znanstveni članek Opis: Background and purpose: The aim of this study was to examine the risk factors, prodromal symptoms, non-motor symptoms (NMS), and motor symptoms (MS) in different Parkinson’s disease (PD) non-motor subtypes, classified using newly established criteria and a data-driven approach.
Methods: A total of 168 patients with idiopathic PD underwent comprehensive NMS and MS examinations. NMS were assessed by the Non-Motor Symptom Scale (NMSS), Montreal Cognitive Assessment (MoCA), Hamilton Depression Scale (HAM-D), Hamilton Anxiety Rating Scale (HAM-A), REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ), Epworth Sleepiness Scale (ESS), Starkstein Apathy Scale (SAS) and Fatigue Severity Scale (FSS). Motor subtypes were classified based on Stebbins’ method. Patients were classified into groups of three NMS subtypes (cortical, limbic, and brainstem) based on the newly designed inclusion criteria. Further, data-driven clustering was performed as an alternative, statistical learning-based classification approach. The two classification approaches were compared for consistency.
Results: We identified 38 (22.6%) patients with the cortical subtype, 48 (28.6%) with the limbic, and 82 (48.8%) patients with the brainstem NMS PD subtype. Using a data-driven approach, we identified five different clusters. Three corresponded to the cortical, limbic, and brainstem subtypes, while the two additional clusters may have represented patients with early and advanced PD. Pearson chi-square test of independence revealed that a priori classification and cluster membership were significantly related to one another with a large effect size (χ2(8) = 175.001, p < 0.001, Cramer’s V = 0.722). The demographic and clinical profiles differed between NMS subtypes and clusters.
Conclusion: Using the actuarial and clustering approach, marked differences between individual NMS subtypes were found. The newly established criteria have potential as a simplified tool for future clinical research of NMS subtypes of Parkinson’s disease. Ključne besede: Parkinson’s disease, non-motor symptoms subtypes, a priori classification, cluster analysis Objavljeno v DKUM: 07.04.2025; Ogledov: 0; Prenosov: 3
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2. Corrosion of NiTiDiscs in different seawater environmentsJelena Pješčić-Šćepanović, Gyöngyi Vastag, Špiro Ivošević, Nataša Kovač, Rebeka Rudolf, 2022, izvirni znanstveni članek Opis: This paper gives an approach to the corrosion resistance analysis and changes in the
chemical composition of anNiTi alloy in the shape of a disc, depending on different real seawater
environments. The NiTi discs were analysed after 6 months of exposure in real seawater environments:
the atmosphere, a tidal zone, and seawater. The corrosion tests showed that the highest corrosion rate
for the discs is in seawater because this had the highest value of current density, and the initial disc
had the most negative potential. Measuring the chemical composition of the discs using inductively
coupled plasma and X-ray fluorescence before the experiment and semiquantitative analysis after
the experiment showed the chemical composition after 6 months of exposure. Furthermore, the
applied principal component analysis and cluster analysis revealed the influence of the different
environments on the changes in the chemical composition of the discs. Cluster analysis detected small
differences between the similar corrosive influences of the analysed types of environments during the
period of exposure. The obtained results confirm that PCA can detect subtle quantitative differences
among the corrosive influences of the types of marine environments, although the examined corrosive
influences are quite similar. The applied chemometric methods (CA and PCA) are, therefore, sensitive
enough to register the existence of slight differences among corrosive environmental influences on
the analysed NiTi SMA. Ključne besede: NiTi discs, corrosion rate, real seawater environment, cluster analysis (CA), principal component analysis (PCA) Objavljeno v DKUM: 20.03.2025; Ogledov: 0; Prenosov: 6
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3. Big data usage in European Countries : cluster analysis approachMirjana Pejić Bach, Tine Bertoncel, Maja Meško, Daila Suša-Vugec, Lucija Ivančić, 2020, izvirni znanstveni članek Opis: The goal of this research was to investigate the level of digital divide among selected European countries according to the big data usage among their enterprises. For that purpose, we apply the K-means clustering methodology on the Eurostat data about the big data usage in European enterprises. The results indicate that there is a significant difference between selected European countries according to the overall usage of big data in their enterprises. Moreover, the enterprises that use internal experts also used diverse big data sources. Since the usage of diverse big data sources allows enterprises to gather more relevant information about their customers and competitors, this indicates that enterprises with stronger internal big data expertise also have a better chance of building strong competitiveness based on big data utilization. Finally, the substantial differences among the industries were found according to the level of big data usage. Ključne besede: big data, cluster analysis, digital divide, k-means, enterprise, industry, Europe, quality Objavljeno v DKUM: 14.01.2025; Ogledov: 0; Prenosov: 3
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4. Directions for the sustainability of innovative clustering in a countryVito Bobek, Vladislav Streltsov, Tatjana Horvat, 2023, izvirni znanstveni članek Opis: This paper presents potential improvements through utilizing the cyclical nature of clusters by human capital, technology, policies, and management. A historical review of the formation and sustainable development of clusters in the US, Europe, Japan, China, and other regions is carried out to achieve this. The aim was to identify and assess the prominent occurrence cases, the central institutional actors, the indicators of their innovative activity, and the schematics of successful cluster management. The theory section covers current classification methods and typology of innovation-territorial economic associations. Consequently, a regression analysis model is produced to identify the potential dominant success factors in implementing the innovation policy of the most successful innovative clusters. Comments on the influence of these predictors on the competitiveness and level of innovative development of the 50 inspected countries follow. As a result of qualitative and quantitative analysis, an overview of the best world practice, the new vision, and its priorities are proposed to improve the efficiency at the level of management structures of innovation clusters. Ključne besede: cluster, cluster policy, state policy, regression analysis, institutions, innovation, R&D Objavljeno v DKUM: 09.04.2024; Ogledov: 306; Prenosov: 130
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5. Multivariate data analysis of natural mineral watersKatja Šnuderl, Marjana Simonič, Jan Mocak, Darinka Brodnjak-Vončina, 2007, izvirni znanstveni članek Opis: Fifty samples of natural mineral waters from springs in Slovenia, Hungary, Germany, Czech Republic and further countries of former Yugoslavia have been analysed. The mass concentration of cations ($Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Fe^{2+}$, $Mn^{2+}$, $NH^+_4$) and anions ($F^-$, $Cl^-$, $I^-$, $NO^-_3$, $SO_4^{2-}$, $HCO_3^-$), the spring temperature, pH, conductivity and carbon dioxide mass concentration have been measured using standard analytical methods. Appropriate statistical methods and different chemometric tools were used to evaluate the obtained data, namely, (i) descriptive statistics, (ii) principal component analysis (PCA), (iii) cluster analysis, and (iv) linear discriminant analysis (LDA). It was confirmed that Slovenian natural mineral water samples differ most from the German ones but are relatively similar to the Czech and Hungarian ones. Water samples from Hungary are similar to waters from the eastern part of Slovenia. Ključne besede: natural mineral water, ion determination, principal component analysis, cluster analysis, linear discriminant analysis Objavljeno v DKUM: 21.12.2015; Ogledov: 1866; Prenosov: 103
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6. Regression analysis of variables describing poultry meat supply in European countriesMiro Simonič, Ksenija Dumičić, Gabrijel Devetak, 2012, izvirni znanstveni članek Opis: In this paper, based on the analysis of official FAOSTAT and EUROSTAT data on poultry meat for 38 European countries for years 2007 and 2009, two hypotheses were examined. Firstly, considering four clustering variables on poultry meat, i.e. production, export and import in kg/capita, as well as the producer price in US $/t, using descriptive exploratory and cluster analysis, the hypothesis that the clusters of countries may be recognized was confirmed. As a result six clusters of similar countries were distinguished. Secondly, based on multiple regression analysis, this paper proofs that there exists the statistically significant relationship of poultry meat production on export and import of that kind of meat, all measured in kg/capita. There is also a high correlation between production, as a dependent, and each of two independent variables. Ključne besede: poultry meat, marketing strategy, cluster analysis, correlation, multiple regression Objavljeno v DKUM: 10.07.2015; Ogledov: 1544; Prenosov: 411
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7. Building data mining applications for CRMAlex Berson, Stephen Smith, Kurt Thearling, priročnik Ključne besede: information society, informatics, information technology, computer networks, internet, enterprise, electronic commerce, electronic marketing, marketing strategy, new economy, data warehousing, data base, data analysis, security, application, data structures, customer, information resources, consumer, statistics, cluster analysis, neural networks, data, trends, cases, case study Objavljeno v DKUM: 01.06.2012; Ogledov: 2743; Prenosov: 87
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