233 research outputs found
History of malware
In past three decades almost everything has changed in the field of malware
and malware analysis. From malware created as proof of some security concept
and malware created for financial gain to malware created to sabotage
infrastructure. In this work we will focus on history and evolution of malware
and describe most important malwares.Comment: 11 pages, 8 figures describing history and evolution of PC malware
from first PC malware to Stuxnet, DoQu and Flame. This article has been
withdrawed due some errors in text and publication in the jurnal that asked
to withdraw article from other source
Stemmer for Serbian language
In linguistic morphology and information retrieval, stemming is the process
for reducing inflected (or sometimes derived) words to their stem, base or root
form; generally a written word form. In this work is presented suffix stripping
stemmer for Serbian language, one of the highly inflectional languages.Comment: 16 pages, 8 figures, code include
Analysis of physical activity as a mediator between non-ergonomic position of upper body segments and musculoskeletal health in bus drivers
The number of injuries and accidents at the workplace are constantly rising, and the most pronounced injuries are related to the musculoskeletal health. Numerous studies have revealed that city bus drivers have a high incidence of musculoskeletal pain. The aim of this study was to determine whether physical activity levels might be a mediator between the non-ergonomic position of the bodyās upper segments and musculoskeletal health in professional bus drivers. The study protocol included the assessment of participantsā musculoskeletal health using the Ćrebro Musculoskeletal Pain Questionnaire, assessment of the non-ergonomic position of the upper body segments when seated by means of the Rapid Upper Limb Assessment, and measuring of the level of physical activity using the Yamax 200 pedometer. The sample consisted of 115 bus drivers, from 40 to 55 years of age, with a minimum work service of 15 years. The relationships among variables were tested using the Spearman correlation coefficient and the Wilcoxon rank sum test to include the selected variables in the multivariate linear regression model. The Box-Cox test indicated the need for logarithmic transformation of the ĆMPQ results used to measure musculoskeletal health, so a log-linear model was used in the regression analysis. The normality of the distribution of the residual regression models was tested by the Shapiro-Wilk test. The main findings of this study indicate that 95.6% of participants reported the presence of musculoskeletal pain and in 24.4% of them a very high risk of the musculoskeletal disorder was observed, which indicated the need for urgent changes. The average number of steps per day was 5,090.8. The physical activity proved (obtained by the regression analysis) as a mediator between the non-ergonomic position of the upper body segments and musculoskeletal health (p=.027). The obtained data may serve as an important argument for designing future public health and kinesiology interventions for the improvement of the health of professional bus drivers
The role and importance of logistics in diversifying the risk of import dependence of the Republic of Serbia on oil and petroleum products
After the outbreak of the conflict in Ukraine in early 2022, a series of events followed that influenced the change of the international order and the entire geopolitical scene. There has been an economic regrouping and redefinition of interstate relations, and in some countries there has been a deterioration or breakin of relations, and in others there has been a deepening and strengthening of cooperation. Bearing in mind that some are leaders in the export of oil and petroleum products, and some are the biggest importers of the same, the international market of these energy products has changed. This is also indicated by the prices of oil and petroleum products on the international market, as a clear indicator of the changed conditions on the supply and demand side. Securitization of the supply of oil and petroleum products, as well as the prevention of negative-inflationary consequences of price shocks of these energies to internal economic flows implies a strategic approach in supply chain management and logistics. Successfully coping with such challenges implies a multifaceted and synchronized approach by the state or competent entities. First of all, states or entities representing them may sign long-term arrangements on the supply of oil and petroleum products, which cannot be considered an absolute solution in the long term, given the general geopolitical circumstances, but also the practice in bilateral cooperation. Then, states can start the production of oil and petroleum products from conventional-commercial sources, if there are financial and objective-technical conditions for this. The third, and no less important approach, is to create conditions for the exploitation of renewable energy sources, which can help users meet their energy needs. This would reduce the demand for other energy sources, so if the country is imported dependent on fossil fuels, the need for imports would also reduce the import dependence of the country. All three approaches are in the function of diversifying the risk of fuel imports, and if this sphere is not given attention, all economic flows of any oil and petroleum products importing country can be drastically disrupted. There are many examples of mistakes made in the procurement strategy of oil and petroleum products, i.e. gas in the foreground. This paper covers the most interesting examples from practice in order to project the risks and damages that imported countries dependent on oil and petroleum products have faced due to the latest developments in Ukraine. In this paper, the authors also point out the economic aspects that reflect possible directions of diversification of risks from the import of oil and petroleum products, as well as the connection of diversification of import risk with supply and logistics in the Republic of Serbia
Sustainable development of pressure equipment using 3D Digital Image Correlation method
As pressure equipment is most commonly used in various industrial fields, making manufacturing processes eco-friendlier (e.g., mass reduction of the final product, material and energy savings, etc.) and transitioning to sustainable production by developing eco-innovative products will have a positive effect on the environment. The aim of this paper is to analyze globe valve housing exposed to internal pressure using full-field experimental 3D digital image correlation (3D-DIC) method and numerical strain and stress data in order to propose improvements for more sustainable development, with respect to practical engineering application of EN standards. The highest von Mises strain values around 0.03% were measured on the point of highest geometrical discontinuity, sphere/cylinder intersection. Stresses of the examined globe valve using numerical and theoretical approach are significantly below material yield limit and allowable stress for internal pressure values of 30 bar, that is significantly higher than nominal operating pressure of 6 bar, proving that structure is over-dimensioned and can be optimized. New experimental procedure development and application in full-field strain analysis contributes to increased valve housing reliability, mass reduction and material and energy savings during manufacturing which directly affects its eco-friendliness, lowers manufacturing price and increases market competitiveness
Repair welding of pressure equipment with unacceptable defects
The paper describes non-destructive testing and the repair welding technology for eliminating defects in the pressure equipment of RHE BB (Bajina Basta) (located in Serbia). The obtained results had justified the proposed technology
Sustainable development of pressure equipment using 3d digital image correlation method
As pressure equipment is most commonly used in various industrial fields, making manufacturing processes eco-friendlier (e.g., mass reduction of the final product, material and energy savings, etc.) and transitioning to sustain-able production by developing eco-innovative products will have a positive effect on the environment. The aim of this paper is to analyze globe valve housing exposed to internal pressure using full-field experimental 3D digital image correlation (3D-DIC) method and numerical strain and stress data in order to propose improvements for more sustainable development, with respect to practical engineering application of EN standards. The highest von Mises strain values around 0.03% were measured on the point of highest geometrical discontinuity, sphere/cylinder intersection. Stresses of the examined globe valve using numerical and theoretical approach are significantly below material yield limit and allowable stress for internal pressure values of 30 bar, that is significantly higher than nominal operating pressure of 6 bar, proving that structure is over-dimensioned and can be optimized. New experimental procedure development and application in full-field strain analysis contributes to increased valve housing reliability, mass reduction and material and energy savings during manufacturing which directly affects its eco- friendliness, lowers manufacturing price and increases market competitiveness
Assessment of integrity of pressure vessels for compressed air
Fracture mechanics approach for structural integrity assessment is described in the case of pressure vessels for compressed air. The results of non-destructive testing indicated unacceptable defects on the vessels and set a base for application of failure analysis diagrams (FAD) and risk-based analysis. Risk matrix are applied with the aim of assessment and analysis of the integrity of the vessels
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