Current usage of Component based Principles for Developing Web Applications with Frameworks: A Literature Review

Component based software development has become a very popular paradigm in many software engineering branches. In the early phase of Web 2.0 appearance, it was also popular for web application development. From the analyzed papers, between this period and today, use of component based techniques for web application development was somewhat slowed down, however, the recent development indicates a comeback. Most of all it is apparent with W3C’s component web working group. In this article we want to investigate the current state of web application development with component approach. Most of all we are interested in which way components are used, which web development frameworks are being used, for which domains is component based web development most popular and successful, etc. How many current web development frameworks explicitly refer to component-based approach? To answer this question, we performed a literature review

Numerička analiza debelostjenih cijevi kod naglog povećanja tlaka

Debelostjene cijevi imaju široku primjenu u strojarstvu, između ostalog i u ispitivanjima eksploziva. Prilikom eksplozije, tlak u cijevi odmah naraste na svoju maksimalnu vrijednost i nakon toga u određenom vremenu padne na nultu vrijednost. Zbog nagle promjene tlaka, koja ovisi o vremenu, statička analiza ne može dobro opisati ponašanje cijevi te je potrebno napraviti dinamičku analizu. Najprije je napravljena verifikacija na jednostavnijem primjeru na kojem se može odrediti analitičko rješenje i to rješenje se uspoređuje s numeričkim. Za verifikacijski model je odabrana greda na dva oslonca na koju u sredini s visine h pada uteg mase m. Proveden je analitički proračun kojim je dobiven maksimalni statički i dinamički progib grede. Te su vrijednosti uspoređene s numeričkim rezultatima. Numerički proračun je proveden pomoću metode konačnih elemenata u računalnom programu Abaqus. Greda je modelirana kao trodimenzionalno tijelo i diskretizirana heksaedarskim elementima prvog reda. Konvergencija je ispitivana na statičkoj analizi, da bi se uštedjelo na vremenu. Nakon toga je napravljena i dinamička analiza primjenom eksplicitne i implicitne metode. Iz rezultata se moglo zaključiti da obje metode za zadani primjer daju približno jednake rezultate, a njihova razlika u odnosu na analitičko rješenje ovisi o pozitivnoj fazi trajanja opterećenja. Nakon verifikacije je napravljena analiza debelostjene cijevi uklještene na jednom kraju i slobodne na drugom kraju te opterećene tlakom iznutra. Radi boljeg opisivanja geometrije, korišten je cilindrični koordinatni sustav. Najprije su se analitičkim proračunom izračunali radijalni pomaci, ekvivalentna, radijalna, cirkularna i aksijalna naprezanja pri statičkom opterećenju. Te veličine se računaju na gornjem rubu cijevi, gdje rubni uvjeti ne utječu na konačne rezultate pa se one mogu puno lakše odrediti nego u ostatku cijevi. Ista je analiza nakon toga provedena numerički, primjenom metode konačnih elemenata u računalnom programu Abaqus. Cijev se diskretizirala 3D heksaedarskim elementima prvog reda. Da bi se uštedjelo na vremenu, konvergencija je napravljena na statičkoj analizi. Osim po visini cijevi, mijenjao se i broj elemenata po debljini cijevi. Rezultati statičke analize su uspoređeni s analitičkim rezultatima i dobiveni rezultati se ne razlikuju previše u odnosu na analitičke rezultate. Nakon toga je napravljena i dinamička analiza na mreži konačnih elemenata kod koje je iskonvergiralo rješenje statičke analize. Dinamička analiza je napravljena primjenom eksplicitne i implicitne metode. Rezultati dobiveni eksplicitnom i implicitnom metodom se razlikuju više nego je to bio slučaj kod grede. Iz rezultata je uočeno da dinamički faktor kod eksplicitne metode iznosi dva i pol, a kod implicitne nešto manje od dva. Maksimalno ekvivalentno naprezanje je veće od granice tečenja materijala pa se zaključuje da su pojedini dijelovi cijevi ušli u plastično područje, zbog čega je potrebno povećati debljinu cijevi ili promijeniti materijal cijevi ili smanjiti količinu eksploziva, čime se dobije manji tlak kojim je cijev opterećena. Kako je u verifikaciji pokazano da se bolje poklapanje s analitičkim rješenjem dobije pri povećanju vremena opterećenja, napravljena je dinamička analiza te cijevi kod vremena trajanja opterećenja od jedne sekunde. Ti su se rezultati usporedili s rezultatima dobivenima kod kraćeg vremena trajanja. Na kraju je napravljena analiza cijevi od jednakog materijala i pri jednakom opterećenju, ali s većom debljinom stijenke i ta je cijev zadovoljila uvjet da su naprezanja niža od granice tečenja

Numeričko optimiranje krutosti konstrukcije

U radu je izvršena numerička analiza krutosti konstrukcije robotiziranog sustava koji se koristi u području neurokirurgije. Dio konstrukcije koji se proračunava je lučni nosač na koji dolazi alat koji se koristi prilikom operacije. Predviđeno je da nosač bude izrađen je aluminija. Cilj proračuna je odrediti kako će se konstrukcija ponašati pod zadanim opterećenjem i koliki će tada biti maksimalni pomaci. Za to je najprije potrebno odrediti koji su konačni elementi optimalni za analizu zadane konstrukcije. Prije numeričke simulacije ponašanja predložene konstrukcije nosača, napravljena je verifikacija na dva modela. Prva verifikacija je provedena na lučnom nosaču oblika četvrtine kružnice punog pravokutnog poprečnog presjeka, ukliještenom na jednom kraju i opterećenom silom na drugom kraju. Druga verifikacija je provedena na lučnom polukružnom nosaču kutijastog profila, ukliještenom na oba kraja i opterećenog silom u sredini. Isti proračuni su provedeni i u računalnom programu Abaqus te je provedena usporedba dobivenih rezultata. Za verifikaciju u Abaqusu su korišteni heksaedarski i tetraedarski konačni elementi prvog i drugog reda. Nakon verifikacije prikazana je numerička analiza pomaka u realnom modelu primjenom metode konačnih elemenata u računalnom programu Abaqus. Konstrukcija je opterećena kontinuiranim opterećenjem koje djeluje na površinu na mjestu gdje dolazi prihvatni mehanizam alata i ukliještena na obje strane. Numerička simulacija je provedena korištenjem heksaedarskih i tetraedarskih elemenata drugog reda. Pretpostavlja se da je jedino opterećenje koje djeluje kontinuirano opterećenje na toj površini. Primarni cilj je analiza pomaka, jer je analizom naprezanja utvrđeno da se u nosaču događaju samo elastične deformacije puno manje od granice tečenja materijala, pa daljnja analiza naprezanja nije potrebna. Na kraju su uspoređeni pomaci za konstrukciju izrađenu od različitih materijala da bi se odredilo koji od materijala je najbolji za izradu konstrukcije. Usporedbom je utvrđeno da je za izradu konstrukcije najpogodniji aluminij

INFLUENCE OF DIMENSIONS OF TEST SPECIMENS ON THE MACHANICAL PROPERTIES OF MATERIAL

U teorijskom dijelu ovog završnog rada bit će opisana mehanička svojstva materijala i metode ispitivanja tih svojstava, dok će u drugom dijelu biti opisan pokus i analiza dobivenih rezultata. Kod opisivanja mehaničkih svojstava, pažnja će biti usmjerena na ispitivanje statičkim vlačnim pokusom i ispitivanje tvrdoće koje će se detaljnije analizirati i dodatno objasniti, dok će ostale metode biti u kratko opisane. Također, bit će i objašnjeno poboljšavanje materijala jer su epruvete poboljšavane. U eksperimentalnom dijelu, pogled je na materijal koji je korišten za izradu epruveta te dodatan opis njegovih karakteristika. Zatim slijedi opisivanje opreme koju smo koristili pri ovome pokusu, plan pokusa, te naposljetku, rezultati pokusa, njegova analiza i zaključak.In the theoretical part of this thesis, mechanical properties of materials and the methods of assesing those properties will be described. In the second segment the experiment will be described and an analysis of the results will be given. When describing the mechanical properties, the focus will be put on the using the static tensile test and the hardness testing which will be analyzed in detail and additionally explained, while the other methods will be described in brief. Also, since the vials were enhanced, we will describe material improvements. In the experimental segment, we will focus on the material used for making the epruvetes and will add a description of its properties. Next, we will describe the equipment used in this experiment, the experimental protocol, and, the results, their analysis and conclusion

Two Years of Gamification of the Course - Lessons Learned

Gamification has been applied in different levels of education (elementary, high school, university) for roughly last 5 years. Many researches deal with how to improve education process by usage of game mechanics and other game based elements in their teaching activities. One of the important part of research in the area of education is what part of the course is involved in the research. If it covers some smaller part of the course, for example, one topic that correspondents to a chapter from common course literature and the gamification is limited to few weeks then we could not get the full picture of its real good and bad sides. Some students got excited when teacher use new methods and lost interest after few weeks. However, the course lasts much longer then few weeks and it is much harder to apply gamification for the full course content and to keep students’ interest during the whole education process like semester with 15 weeks. The paper presents our experience with gamified course in two consecutive academic years. We gamified whole course content and learning activities. First year we had half students in gamified version of the course as an experimental group and the other half of students as a control group. The experimental group based on their groupings had all gamified experiences that standard Moodle distribution and chosen plugins provide. The control group was not formally and fully included in all aspects of gamified version of the course but the teachers manually record all their earnings (badges, experience points etc.) even the students were not aware of it. We made some comparisons based on those groups and their achievements, usage of the Moodle etc. We analysed the students’ survey they fill at the end of the course, also our remarks we made during the course. Those were inputs to smaller adjustments for next year (for example we provided more information about the best award). In the second year, the whole course student population was using gamified version of the course. Again, we analysed the students’ survey they fill at the end of the course. We compared those two years in many elements. Some of results were expected but some were not. Finally, we compare our experience with other researches in the area of gamification

News Cohesiveness: an Indicator of Systemic Risk in Financial Markets

Motivated by recent financial crises significant research efforts have been put into studying contagion effects and herding behaviour in financial markets. Much less has been said about influence of financial news on financial markets. We propose a novel measure of collective behaviour in financial news on the Web, News Cohesiveness Index (NCI), and show that it can be used as a systemic risk indicator. We evaluate the NCI on financial documents from large Web news sources on a daily basis from October 2011 to July 2013 and analyse the interplay between financial markets and financially related news. We hypothesized that strong cohesion in financial news reflects movements in the financial markets. Cohesiveness is more general and robust measure of systemic risk expressed in news, than measures based on simple occurrences of specific terms. Our results indicate that cohesiveness in the financial news is highly correlated with and driven by volatility on the financial markets

Process Model Improvement for Source Code Plagiarism Detection in Student Programming Assignments

In programming courses there are various ways in which students attempt to cheat. The most commonly used method is copying source code from other students and making minimal changes in it, like renaming variable names. Several tools like Sherlock, JPlag and Moss have been devised to detect source code plagiarism. However, for larger student assignments and projects that involve a lot of source code files these tools are not so effective. Also, issues may occur when source code is given to students in class so they can copy it. In such cases these tools do not provide satisfying results and reports. In this study, we present an improved process model for plagiarism detection when multiple student files exist and allowed source code is present. In the research in this paper we use the Sherlock detection tool, although the presented process model can be combined with any plagiarism detection engine. The proposed model is tested on assignments in three courses in two subsequent academic years

Common Metamodel of Component Diagram and Feature Diagram in Generative Programming

Component-based software engineering and generative programming are common approaches in software engineering. Each approach has some benefits and domain of usage. Component-based development is used to build autonomous components that can be further combined in different ways, while generative programming is more suitable when building systems that have different variants. Before a variable component based system can be build, it needs to be modeled. In this article, a new common metamodel that aims to enable modeling a system which combines both component-based development and generative programming is introduced. The introduced metamodel proposed in this paper combines the component diagram that is used to model systems in component-based development and the feature diagram that is employed in modeling systems in generative programming. The combined metamodel enables modeling of variable systems using components

Integrity constraints in graph databases - implementation challenges

Graph databases are becoming more and more popular as they represent a good alternative to relational databases for some problem scenarios. Searching a graph is sometimes very convenient, unlike writing complex SQL queries that require a table to be joined to itself several times. However, graph databases do not support all the constraints that are familiar and used in relational databases. In this paper, we discuss integrity constraints in graph databases and technical implementation issues that prevent these constraints from being specified

Integrity constraints in graph databases - implementation challenges

Graph databases are becoming more and more popular as they represent a good alternative to relational databases for some problem scenarios. Searching a graph is sometimes very convenient, unlike writing complex SQL queries that require a table to be joined to itself several times. However, graph databases do not support all the constraints that are familiar and used in relational databases. In this paper, we discuss integrity constraints in graph databases and technical implementation issues that prevent these constraints from being specified