Tensile Membrane Structure Forces Dependence on Different Parameters Under Point Load Action

Point load actions may have a significant impact on deflections of tensile membrane structures. Research presented in this paper is aimed at exploring the effects of point load actions on membrane forces of tensile membrane structures. Therefore, three different parameters of the structure were varied, and the membrane forces resulting from point loads were monitored. Variable parameters are the height of the model, the intensity of prestressing forces, and the orientation of the membrane material. The research was done on models in specialized software. In order to evaluate the significance of point load effects, membrane forces were compared to those under snow load. The results of the research show the layout of membrane forces under point load and dependence of maximal membrane forces on the varied parameters. Specific sets of analyzed parameters lead to significant values of maximal membrane forces under point load actionKoncentrisane sile mogu da izazivaju znatne ugibe zategnutih membranskih konstrukcija. Istraživanje predstavljeno u ovom radu bavi se efektima dejstva koncentrisane sile na sile zatezanja membranskih konstrukcija. Kako bi se ovi efekti ispitali, varirana su tri parametra konstrukcije, a praćene su sile zatezanja izazvane dejstvom koncetrisane sile. Varirani parametri jesu visina modela, intenzitet sila prednaprezanja i orijentacija membranskog materijala. Istraživanje je sprovedeno na modelima formiranim u specijalizovanom softveru. Kako bi se ocenio značaj efekata dejstva koncentrisane sile, rezultujuće sile zatezanja upoređene su sa silama zatezanja pod dejstvom opterećenja od snega. Rezultati istraživanja pokazuju raspored intenziteta sila zatezanja u membrani pod dejstvom koncentrisane sile i zavisnost maksimalnih sila zatezanja od ispitivanih parametara. Pri određenim kombinacijama ispitivanih parametara, koncentrisana sila izaziva vrlo značajne sile zatezanja

Malware detection at runtime for resource-constrained mobile devices: data-driven approach

The number of smart and connected mobile devices is increasing, bringing enormous possibilities to users in various domains and transforming everything that we get in touch with into smart. Thus, we have smart watches, smart phones, smart homes, and finally even smart cities. Increased smartness of mobile devices means that they contain more valuable information about their users, more decision making capabilities, and more control over sometimes even life-critical systems. Although, on one side, all of these are necessary in order to enable mobile devices maintain their main purpose to help and support people, on the other, it opens new vulnerabilities. Namely, with increased number and volume of smart devices, also the interest of attackers to abuse them is rising, making their security one of the main challenges. The main mean that the attackers use in order to abuse mobile devices is malicious software, shortly called malware. One way to protect against malware is by using static analysis, that investigates the nature of software by analyzing its static features. However, this technique detects well only known malware and it is prone to obfuscation, which means that it is relatively easy to create a new malicious sample that would be able to pass the radar. Thus, alone, is not powerful enough to protect the users against increasing malicious attacks. The other way to cope with malware is through dynamic analysis, where the nature of the software is decided based on its behavior during its execution on a device. This is a promising solution, because while the code of the software can be easily changed to appear as new, the same cannot be done with ease with its behavior when being executed. However, in order to achieve high accuracy dynamic analysis usually requires computational resources that are beyond suitable for battery-operated mobile devices. This is further complicated if, in addition to detecting the presence of malware, we also want to understand which type of malware it is, in order to trigger suitable countermeasures. Finally, the decisions on potential infections have to happen early enough, to guarantee minimal exposure to the attacks. Fulfilling these requirements in a mobile, battery-operated environments is a challenging task, for which, to the best of our knowledge, a suitable solution is not yet proposed. In this thesis, we pave the way towards such a solution by proposing a dynamic malware detection system that is able to early detect malware that appears at runtime and that provides useful information to discriminate between diverse types of malware while taking into account limited resources of mobile devices. On a mobile device we monitor a set of the representative features for presence of malware and based on them we trigger an alarm if software infection is observed. When this happens, we analyze a set of previously stored information relevant for malware classification, in order to understand what type of malware is being executed. In order to make the detection efficient and suitable for resource-constrained environments of mobile devices, we minimize the set of observed system parameters to only the most informative ones for both detection and classification. Additionally, since sampling period of monitoring infrastructure is directly connected to the power consumption, we take it into account as an important parameter of the development of the detection system. In order to make detection effective, we use dynamic features related to memory, CPU, system calls and network as they reflect well the behavior of a system. Our experiments show that the monitoring with a sampling period of eight seconds gives a good trade-off between detection accuracy, detection time and consumed power. Using it and by monitoring a set of only seven dynamic features (six related to the behavior of memory and one of CPU), we are able to provide a detection solution that satisfies the initial requirements and to detect malware at runtime with F- measure of 0.85, within 85.52 seconds of its execution, and with consumed average power of 20mW. Apart from observed features containing enough information to discriminate between malicious and benign applications, our results show that they can also be used to discriminate between diverse behavior of malware, reflected in different malware families. Using small number of features we are able to identify the presence of the malicious records from the considered family with precision of up to 99.8%. In addition to the standalone use of the proposed detection solution, we have also used it in a hybrid scenario where the applications were first analyzed by a static method, and it was able to detect correctly all the malware previously undetected by static analysis with false positive rate of 3.81% and average detection time of 44.72s. The method, we have designed, tested and validated, has been applied on a smartphone running on Android Operating System. However, since in the design of this method efficient usage of available computational resources was one of our main criteria, we are confident that the method as such can be applied also on the other battery-operated mobile devices of Internet of Things, in order to provide an effective and efficient system able to counter the ever-increasing and ever-evolving number and a variety of malicious attacks

PARAMETRIC DESIGN OF 3D PRINTED RIBBED SLAB SYSTEM BASED ON NATURE-INSPIRED PATTERNS

The interest in pattern geometry and its application to architecture may be seen throughout history. While some authors were fascinated by pattern aesthetics, others were focused on their effectiveness and underlying principles of pattern formation. In continuing with the work of the second group of authors, this paper reviews opportunities for efficient ways of implementing patterns in the design of architectural elements, supported by recent developments in parametric design and digital fabrication techniques. This paper aims to analyze pattern configurations found in nature in order to determine the underlying generation principles and the potential of their application for 3D printed slab systems. Using case study methodology, selected patterns will be applied in developing a generative parametric design system, which will further be tested in creating and (small-scale) fabricating ribbed slab elements. The result of the research is the generalization of a design approach based on principles of natural pattern formation to produce sustainable design solutions that rely on the transposition of the inherent efficiency of natural systems, such as low energy or material consumption

Prevalence and characteristics of endometrial polyps in patients with abnormal uterine bleeding

Background/Aim. The prevalence of endometrial polyps (EPs) in the general female population is about 24%. Abnormal uterine bleeding is frequently the presenting symptom of EPs. The aim of this study was to determine the prevalence and characteristics of EPs in patients with abnormal uterine bleeding. Methods. The prevalence and characteristics of EPs were investigated in 961 patients with abnormal uterine bleeding who underwent dilatation and curettage between January and December 2006. Regarding histopathological features of EPs (presence of atypical hyperplasia or endometrial carcinoma), patients were divided into two groups: group A - patients who had EPs and EPs with hyperplasia without atypia (n = 204) and group B - patients who had EPs with atypical hyperplasia and EPs with carcinoma (n = 7). Results. In 211 (21.94%) patients EPs were found with abnormal uterine bleeding. Histopathologically, there were 175 (82.94%) EPs, 29 (13.74%) EPs with hyperplasia without atypia, 5 (2.37%) EPs with atypical hyperplasia, and 2 (0.95%) EPs with endometrial carcinoma. Contrary to the patients with EPs and EPs with hyperplasia without atypia (group A), patients who had EPs with atypical hyperplasia and EPs with carcinoma (group B) were older (p < 0.05), and more commonly postmenopausal (p < 0.05) and with hypertension (p < 0.05), all of statistical significance. Conclusion. The prevalence of endometrial polyps in patients with abnormal uterine bleeding according to our data was 21.95%. Atypical hyperplasia and endometrial carcinoma were rarely confined to a polyp. Older age, postmenopausal period and hypertension may increase the risk of premalignant and malignant changes in endometrial polyps

Pristup zasnovan na performansama u projektovanju prostornih struktura slobodne forme

This paper is related to the fact that use of computational tools for form generation, analysis and digital fabrication (CAD/CAM/CAE) in an efficient way enables accurate representation of ideas, simulation of diverse impact and production of rational design solutions. Application of geometrical and numerical computational methods and adoption of performance based priorities enables formal exploration in constrained conditions and improvement of architectural engineering design process. Implementation of advanced technologies in 3D digital design process facilitates production of unconventional complex designs, their verification by construction of physical models and experimental diagnostics, as phase preceding construction of real structure. Within this work concept that provides design of non-standard, context-specific, freeform structure using rapid prototyping technology and 3D optical measurement will be reviewed. The analyzed design solution of roof structure above atrium of National Museum in Belgrade has a function to demonstrate the effectiveness of this approach.Rad je povezan sa činjenicom da je korišćenjem alata za generisanje forme, analizu i digitalnu proizvodnju (CAD/CAM/CAE) na efikasan način omogućena precizna prezentacija ideja, simulacija različitih uticaja i produkcija racionalnih projektnih rešenja. Primena geometrijskih i numeričkih kompjuterskih metoda i usvajanja prioriteta zasnovanih na performansama omogućava formalna istraživanja u ograničenim uslovima i unapređenje procesa projektovanja u oblasti arhitektonskog inženjerstva. Implementacija naprednih digitalnih tehnologija u 3D proces projektovanja omogućava produkciju nekonvencionalnih kompleksnih oblika, njihovu verifikaciju konstrukcijom fizičkih modela i eksperimentalnu dijagnostiku, kao faze koja prethode izgradnji realne strukture. U okvirima ovog rada razmatraće se koncepti koji omogućavaju projektovanje nestandardne, kontekstualno specifične strukture slobodne forme primenom tehnologije brze proizvodnje prototipova i 3D optičkog merenje. Analizirano projektno rešenje krova iznad atrijuma Narodnog Muzeja u Beogradu u funkciji je potvrđivanja efikasnosti ovakvog pristupa

The influence of the quality of metabolic control on the outcome of treatment with physical procedures of patients with gonarthrosis and type 2 diabetes melitus

UVOD: Gonartroza i DM tip 2 su dve bolesti koje sve češće koegzistiraju, što zbog velike prevalencije, što zbog brojnih zajedničkih faktora rizika. Primena fizikalne terapije zauzima značajno mesto u lečenju kako pacijenata sa gonartrozom, tako i pacijenata sa DM tip 2. Magnetoterapija i kineziterapija su agensi koji se najčešće koriste za lečenje pacijenata sa gonartrozom. CILj: Osnovni cilj ovog rada bio je da se ispita uticaj DM tip 2 na ishod lečenja fizikalnom terapijom pacijenata sa gonartrozom. METODE: Eksperimentalna studija kojom je obuhvaćeno 66 pacijenata, podeljeni u dve grupe u odnosu na prisustvo DM tip 2. Eksperimentalnu grupu su činili pacijenti sa gonartrozom i DM tip 2, a kontrolnu grupu pacijenti sa gonartrozom. Tokom analize podataka eksperimentalna grupa je podeljena na pacijente sa gonartrozom i regulisanim DM tip 2 i grupu sa gonartrozom i neregulisanim DM tip 2. Varijable praćene u istraživanju su biohemijski parametri, citokini (TNF-α, IL-6, IL-17, IL-10, INF-γ, IL-12, IL-23, TGF-β, IL-33, Gal-3)), WOMAC upitnik, Mc-Gill upitnik, VAS skala, EQ5D upitnik, Lequesne indeks, test monofilamenta, MNSI, NSS, NDS, MMT, merenje obima pokreta u zglobu. REZULTATI: Rezultati pokazuju da fizikalna terapija ima pozitivan efekat kod pacijenata sa gonartrozom i DM tip 2, kao i kod pacijenta sa gonartrozom, mereno kroz skor WOMAC indeksa. DM tip 2 ima negativan efekat na fizikalnu terapiju kod pacijenata sa gonartrozom. ZAKLjUČAK: Na osnovu dobijenih rezultata možemo zaključiti da loša glikoregulacija može imati negativan uticaj na ishod lečenja fizikalnom terpijom pacijenta sa gonartrozom.INTRODUCTION: Gonarthrosis and DM type 2 are two diseases that coexist more and more often, due to their high prevalence and due to numerous common risk factors. The application of physical therapy occupies an important place in the treatment of both patients with gonarthrosis and patients with DM type 2. Magnetotherapy and kinesitherapy are the agents most often used to treat patients with gonarthrosis. AIM: The main goal of this work was to examine the impact of DM type 2 on the outcome of physical therapy treatment of patients with gonarthrosis. METHODS: An experimental study that included 66 patients, divided into two groups in relation to the presence of DM type 2. The experimental group consisted of patients with gonarthrosis and DM type 2, and the control group consisted of patients with gonarthrosis. During data analysis, the experimental group was divided into patients with gonarthrosis and regulated DM type 2 and a group with gonarthrosis and unregulated DM type 2. The variables monitored in the study were biochemical parameters, cytokines (TNF-α, IL-6, IL-17, IL-10, INF-γ, IL-12, IL-23, TGF-β, IL-33, Gal-3)), WOMAC questionnaire, Mc-Gill questionnaire, VAS scale, EQ5D questionnaire, Lequesne index, monofilament test, MNSI, NSS, NDS, MMT, wrist range of motion measurement. THE RESULTS: The results show that physical therapy has a positive effect in patients with gonarthrosis and DM type 2, as well as in patients with gonarthrosis, as measured by the WOMAC index score. DM type 2 has a negative effect on physical therapy in patients with gonarthrosis. CONSLUSION: Based on the obtained results, we can conclude that poor glycoregulation can have a negative impact on the outcome of physical therapy treatment of a patient with gonarthrosi

Odnos učenika prema nastavi i učenju

The paper presents the results of a pilot-study as a part of TIMSS 2007 study project that is a segment of a large international project on the study of educational trends for primary school pupils in the field of mathematics and natural sciences. The first part of the paper deals with analyzing structural features and describing variables that TIMSS concept defines in order to investigate the relation between pupils’ self-esteem and their evaluation of school subjects considering two fields of study: mathematics and natural sciences. The second part of the paper describes pupils’ educational aspirations and their interdependent relationship with self-esteem and evaluation. The third part of the paper deals with some relevant predictors of pupils’ educational aspirations and their attitudes towards mathematics and natural sciences. At the end, some recommendations have been offered that can further stimulate a change in education values of our society.U radu su izloženi nalazi probnog istraživanja u okviru studije TIMSS 2007 koji predstavljaju deo obimnog međunarodnog projekta proučavanja trendova obrazovnog postignuća učenika osnovnih škola u oblasti matematike i prirodnih nauka. Prvi deo rada odnosi se na analizu strukturalnih karakteristika i opis varijabli kojima je u TIMSS koncepciji operacionalizovan odnos samopouzdanja učenika i vrednovanja školskih predmeta u oblasti matematike i prirodnih nauka. Drugi deo rada odnosi se na opis obrazovnih aspiracija učenika i međuzavisnost sa samopouzdanjem i vrednovanjem. U trećem delu rada razmatraju se neki relevantni prediktori obrazovnih aspiracija učenika i njihov odnos prema matematici i prirodnim naukama. Na kraju, predložene su neke od konkretnih preporuka koje mogu dovesti do promene obrazovnih vrednosti našeg društva

Uticaj mikroorganizama na ublažavanje posledica abiotičkog stresa kod poljoprivrednih kultura

Microorganisms could play an important role in adaptation strategies and increase of tolerance to abiotic stresses in agricultural plants. Plant-growth-promoting rhizobacteria (PGPR) mitigate most effectively the impact of abiotic stresses (drought, low temperature, salinity, metal toxicity, and high temperatures) on plants through the production of exopolysaccharates and biofilm formation. PGPR mitigate the impact of drought on plants through a process so-called induced systemic tolerance (IST), which includes: a) bacterial production of cytokinins, b) production of antioxidants and c) degradation of the ethylene precursor ACC by bacterial ACC deaminase. Symbiotic fungi (arbuscular mycorrhizal fungi) and dual symbiotic systems (endophytic rhizospheric bacteria and symbiotic fungi) also tend to mitigate the abiotic stress in plants.Mikroorganizmi mogu imati značajnu ulogu u strategijama adaptacija i povećanju tolerantnosti poljoprivrednih biljnih vrsta na abiotičke stresove. Najveći uticaj ublažavanja abiotičkih stresova na biljku (suša, niske temperature, salinitet, toksičnost metala i visoke temperature) imaju mikroorganizmi koji naseljavaju rizosferno zemljište, a promoteri su biljnog rasta (PGPR), kroz produkciju egzopolisaharida i formiranjem biofilma. PGPR ublažavaju uticaj suše na biljke indukovanim sistemom tolerancije (IST): a) produkcijom bakterijskog citokinina b) produkcijom antioksidanata i c) degradacijom etilen prekursora ACC bakterijskim ACC-deaminazom. Takođe i simbiozne gljive (abscular mycorrhizal fungi) i dual simbiozni sistemi (rhizosphere, endophytic bacteria i symbiotic fungi) utiču na ublažavanje abiotičkih stresova u biljkama

Traženje forme ljuski zasnovano na izogeometrijskoj analizi

The paper reviews potentials of the application of isogeometric analysis (IGA) in the pro­cesses of form-finding of shell structures. Shaping of those specific spatial structural typolo­gies is determined by consideration of the form-structure interrelation, therefore the sustainable approach to design implies application of form-finding techniques. In this paper, we applied the frequently used form-finding principle a inverted model strategy, more precisely concept of inverted displacements. Contrary to the similar studies which apply standard finite element (FE) discretization, we proposed an application of isogeometric modeling of the structure. Isogeome­try implies analysis based on the exact definition of the initial geometry, facilitating design and analysis by application on the single data type - model. Advantage of the conservation of geometric representation is especially evident in the case of shell structure designs, bearing in mind their continuously curved geometry. We applied NURBS based isogeometric analysis in which geometry and displacement field are described by NURBS surfaces. Modeling of the structural performances was conducted by isogeometric shell elements. Presented numerical experiment has a function to confirm the effectiveness of the proposed approach.Radom se razmatraju potencijali primene izogeometrijske analize u procesima traženja formi ljuski. Oblikovanje ovih specifičnih prostornih strukturalnih tipologija određeno je razmatranjem interrelacije forma-struktura, zbog čega održivi pristup njihovom projektovanju podra­zumeva primenu tehnika traženja forme. U okviru ovog rada primenjena je strategija obrnutog modela, često korišćen princip traženja forme, tačnije koncept obrnutih pomeranja. Za razliku od sličnih istraživanja u kojima se koristi standardna diskretizacija konačnim elementima (FE), ovim radom se predlaže izogeometrijsko modelovanje strukture. Izogeometrija podrazumeva analizu zasnovanu na egzaktnoj definiciji početne geometrije, čime je omogućeno projektovanje i analiza upotrebom jedinstvenog tipa podataka - modela. Prednost konzervacije geometrijske reprezentacije posebno dolazi do izražaja u slučaju projektovanja ljuski imajući u vidu njihovu kontinualno zakrivljenu geometriju. Primenjena je NURBS izogeometrijska analiza, u kojoj se geometrija i polje pomeranja opisuju korišćenjem NURBS površi. Modelovanje strukturalnih performansi izvršeno je korišćenjem izogeometrijskog elementa ljuske. Prikazan numerički ek­speriment u funkciji je potvrđivanja efikasnosti predloženog pristupa

Role of rootstock and apple fruit tissue in antioxidant activity

During two consecutive years (2018 and 2019) we investigated the effect of two clonal rootstocks on fruit weight, contents of some non-nutrients and total antioxidant capacity (TAC) in the flesh and peel of CV. 'Hapke' apple. Results showed that fruit weight was significantly higher on M.9 T337 than on M.26 rootstock and similar in both 2018 and 2019. M.26 rootstock significantly improved titratable acidity (TA), vitamin C content, total phenolic content (TPC), total flavonoid content (TFC) and TAC in comparison with M.9 T337. As regards fruit tissue, the peel was a significantly better source of acids, vitamin C and phenolic compounds, and had higher antioxidant capacity than the flesh. However, the rootstock × fruit tissue interaction for the content of phenolic compounds indicated the complex nature of accumulation and distribution of acidity, vitamin C and phenolic compounds in apples.Publishe