POWER TRANSFORMER HEALTH INDEX ESTIMATION USING EVIDENTIAL REASONING

Market-oriented power distribution system requires a well-planned budget with scheduled preventive and corrective maintenance during a replacement of units that are in an unsatisfactory condition. In recent years, the concept of the transformer health index as an integral part of resource management was adopted for the condition assessment and ranking of ETs. However, because of the lack of regular measurement and inspections, the confidence in health index value is greatly reduced.The paper proposes a novel methodology for the ET condition assessment and the lifetime increase through the establishment of priorities for control and maintenance. The solution is based on the upgraded health index, where the confidence to the measurement results is calculated using Evidential reasoning algorithm based on Dempster – Shafer theory. A novel, two – level hierarchical model of ET health index is proposed, with real weighting factors values. This way, the methodology for ET ranking includes the value of available information to describe ET current state. The proposed methodology is tested on real data of an installed ET and compared with the traditional health index calculation

Multi-channel system for remote power quality monitoring of electricity supplied by public distribution networks

Peer Reviewe

SELF-CONCEPT AS THE DETERMINANT OF PHYSICAL ACTIVITY OF PREADOLESCENTS IN PHYSICAL EDUCATION CLASSES

The aim of this research was twofold: a) the examination of the relations between the construct of self-concept (sport competence and physical self) and the criterion (volume of physical activity and intensity of physical activity) in physical education classes for preadolescents and b) the examination of the contribution of the variables of self-concept to the predictions of the variance criterion, thus the partial influence of predictor variables in the prediction of physical activities of students in late childhood. The following instruments were used on the relevant sample of participants from Valjevo (N=212) whose average age was 12.5 years: self-perception of the self-concept questionnaire (SPPC), pedometer (CoachGear) and heart rate monitor (Suunto memory belt) for measuring the volume and intensity of the physical activity. The internal consistency coefficient of the SPPC questionnaire was (α=.82) for sport competence and (α=.85) for the physical self, which indicated the satisfactory reliability and its applicability of the Serbian preadolescent population. Using the Pearson correlation coefficient, with a probability of 99%, the low statistically relevant positive linear correlation between the examined variables was determined. Using the model of multiple linear regression analysis, it was determined that the construct of self-concept explains 19% of the perceived volume of physical activity variance and 20% of the intensity of the physical activity variability for the relevance threshold (p≤.01). The results of the regression equation indicated that the independent variable Sport Competence explained the variance in the Volume of physical activity and the Intensity of physical activity variables with preadolescents (β=.32, β=.30) in a statistically significant manner, while the variable Physical self was not a statistically significant partial predictor of any of the criteria. The obtained empirical findings are in accordance with the results of the previous studies, and there was a discussion about the theoretical and practical implications of the obtained findings

Antimicrobial treatment of Corynebacterium striatum invasive infections: a systematic review

The aim of this study was to establish an evidence-based guideline for the antibiotic treatment of Corynebacterium striatum infections. Several electronic databases were systematically searched for clinical trials, observational studies or individual cases on patients of any age and gender with systemic inflammatory response syndrome, harboring C. striatum isolated from body fluids or tissues in which it is not normally present. C. striatum had to be identified as the only causative agent of the invasive infection, and its isolation from blood, body fluids or tissues had to be confirmed by one of the more advanced diagnostic methods (biochemical methods, mass spectrometry and/or gene sequencing). This systematic review included 42 studies that analyzed 85 individual cases with various invasive infections caused by C. striatum. More than one isolate of C. striatum exhibited 100% susceptibility to vancomycin, linezolid, teicoplanin, piperacillin-tazobactam, amoxicillin-clavulanate and cefuroxime. On the other hand, some strains of this bacterium showed a high degree of resistance to fluoroquinolones, to the majority majority of β-lactams, aminoglycosides, macrolides, lincosamides and cotrimoxazole. Despite the antibiotic treatment, fatal outcomes were reported in almost 20% of the patients included in this study. Gene sequencing methods should be the gold standard for the identification of C. striatum, while MALDI-TOF and the Vitek system can be used as alternative methods. Vancomycin should be used as the antibiotic of choice for the treatment of C. striatum infections, in monotherapy or in combination with piperacillin-tazobactam. Alternatively, linezolid, teicoplanin or daptomycin may be used in severe infections, while amoxicillin-clavulanate may be used to treat mild infections caused by C. striatum

POWER TRANSFORMER MONITORING AND AMR SYSTEM SUPPORT FOR COMBINED OPERATION OF DISTRIBUTED RES AND DEMAND SIDE MANAGEMENT

ABSTRAC

FACTORIAL STRUCTURE OF THE RELATIONSHIP BETWEEN AGGRESSIVENESS AND PERSONALITY DIMENSIONS IN JUNIOR KARATEKAS

The goal of this study was to identify the factorial structure and the relation of aggressiveness and basic personality dimensions, as well as metric characteristics (reliability) of the applied scales and subscales. The study was conducted on a sample (N = 287) consisting of both genders, aged between 14-16 years. The following measuring instruments were used:  Buss-Perry Aggression Questionnaire (AQ), Eysenck Personality Questionnaire (EPQ), and the Big Five Plus Two Inventory (BF+2). The applied scales and subscales point to a high reliability type of internal consistency (α > .70), which confirms the appropriate psychometric characteristics, as well as validity of instruments on the athletic population. Principal Component Analysis (PCA) was performed, and with Varimax rotation, three dimensions with latent values of more than one were extracted, and they explain 60,41% of total variance. Results have shown that in the structure of the first component, factors of the second order (Psychoticism and Social desirability from the EPQ, Aggressiveness and Negative Valence from BF+2) significantly contribute to aggressive reactions. The second isolated component is saturated by personality constructs from the EPQ and BF+2 models, which can be interpreted as intrusiveness and domination. The composition of the third component – uncontrollable physical aggression – is maximally burdened by negative correlations of the dimensions Psychoticism and Social desirability from the EPQ, Conscientiousness (in a negative direction) and Negative Valence from BF+2, as well as Physical aggression from the AQ, Aggressiveness from BF+2, and Rage from AQ. In this study, theoretical and practical implications required for operationalization of these findings are discussed.Key words: karate athletes, AQ, EPQ-R, BF+

Integrated Transformer Health Estimation Methodology Based on Markov Chains and Evidential Reasoning

Due to the large number of power transformers (ETs) in the distribution system, there is a need for a relatively simple representation of the status of each unit in order to more easily determine where and how to allocate the budget for preventive and corrective maintenance. In recent years, the concept of the transformer health index (HI) as an integral part of resource management was adopted for the condition assessment and ranking of ETs. HI algorithms take different forms and can be determined based on a large number of specific parameters. However, the main problem in HI methodology or any modern diagnostic technique is the existence of regular measurements and inspections and accurate test results. The paper proposes a solution in the form of the upgraded HI and the novel methodology for ET ranking including the value of available information to describe ET current state. The confidence to the measurement results is calculated using evidential reasoning (ER) algorithm based on Dempster–Shafer theory. The contribution to the ER methodology is the calculation of the initial degrees of belief using Markov chains. The aging process of an ET and transition probabilities from state to state are modelled using the statistical data for the population of 300 ETs and 20 years monitoring data. The proposed methodology is tested on the real data for 110/35 kV transformer, and in the second case, compared to the sample of 30 110/x kV transformers with traditional HI calculation

Factors Influencing Hookah Smoking in High School Students

© 2018 Minela Z. Vapljanin, published by Sciendo. In recent years, the prevalence of hookah smoking has increased worldwide, particularly in young people, which may have potentially serious consequences for their health. The aim of this study was to examine the factors associated with the consumption of hookah by high school students. The present study was conducted in the city of Novi Pazar, and students aged 17-19 years attending the following high schools were included: Medical School, Grammar School, Economic-Commerce School and Catering School. The study was designed as a case-control study. The cases were students who consumed nargile, while the control group consisted of students who had never smoked nargile. A special questionnaire was constructed for the purpose of this research, which was used to evaluate the opinions of adolescents on the consumption of nargile. Our research included a total of 270 seniors in high schools in Novi Pazar. The average age of the students was 18 years. The most important factors that may contribute to start using nargile were: previous consumption of nargile by older family members, divorced parents, and active smoking of cigarettes by other family members. Most students emphasized that hookah smoking is socially unacceptable form of behavior. Also, hookah smoker were neither more attractive nor popular. Nargile consumption is more common by adolescents whose parents are divorced, as well as by adolescents whose family members are smoking nargile or tobacco. The most common reason for nargile consumption among adolescents is a desire for relaxation