Poluvodiči

Svojstva poluvodiča najbolje objašnjava teorija vrpci koju je moguće tumačiti preko teorije molekulskih orbitala i modela gotovo slobodnog elektrona. Teorija molekulskih orbitala nastanak valentne i vodljive vrpce objašnjava kao nastanak veznih i protuveznih orbitala dok model gotovo slobodnog elektrona dopuštena energetska stanja računa uz pomoć kvantnog sustava čestice u kutiji s periodičnim potencijalom. Pored elementarnog silicija koji je primjer intrinzičnih poluvodiča postoje i ekstrinzični poluvodiči. Dva su tipa ekstrinzičnih poluvodiča, n-tip i p-tip. Kod n-tipa poluvodiča za vođenje su odgovorni elektroni, a kod p-tipa to su šupljine. Silicij se dobiva redukcijom silicijevog dioksida nakon čega ga je potrebno dodatno pročistiti što je moguće napraviti kemijskom depozicijom para. Tako nastali polikristalni silicij najčešće se Czochralskijevim procesom prevodi u monokristalni silicij. Monokristal silicija reže se na tanke pločice (vafere) iz kojih se daljnjim procesima fotolitografije, jetkanja i dopiranja dobivaju čipovi. Najznačajni izumi današnje moderne tehnologije svoj temelj imaju u poluvodičima. Zbog energetske učinkovitosti LED žarulje iz upotrebe izbacuju halogenske, a fotodiode omogućuju proizvodnju električne energije uz minimalno zagađenje okoliša. Iako je upotreba raznolika, princip je isti i temelji se na p-n spoju poluvodiča. Pridruži li se p-n spoju još jedan sloj poluvodiča, nastat će p-n-p ili n-p-n spoj koji su osnove tranzistora

Kako gradonačelnici u zemljama srednje i jugoistočne Europe koriste Facebook

The ever increasing rise of social media network users consequently leaves a mark on political communication. While social media tools are already adopted in political marketing, primarily in election campaigning, governments are still new in using social media. The aim of this study is to examine how Facebook is used by city mayors in countries of Central and Southeastern Europe in two months period, from March 1st to April 30th of 2012. Using content analysis we first analyzed status massages in order to see what kind of status messages they post: personal or political. Secondly, we conducted an analysis of comments on the examined statuses, in order to examine if citizens make constructive, cynical, supportive or neutral comments. We examined ten city mayors’ Facebook pages in five countries, Bulgaria, Croatia, Hungary, Macedonia and Slovenia. The results have revealed that city mayors in Central and Southeastern Europe use Facebook almost exclusively for official purposes. Secondly, the analysis of citizens’ comments demonstrates that expressing cynicism on Facebook is not the trend in these countries. The findings further confirm that Facebook is a good platform for gathering supporters, while there were no strong evidence found that it serves as platform for constructive discussion. The paper finally discusses how politician’s status messages can engage a larger number of citizens.Sve veći broj korisnika društvenih mreža ostavio je trag i na političku komunikaciju. Dok je upotreba društvenih mreža u političkom marketingu već uvriježena, prvenstveno u izbornim kampanjama, vlade i lokalna uprava i samouprava još su uvijek na početcima korištenja društvenih mreža. Cilj je ovog istraživanja ispitati kako gradonačelnici u zemljama srednje i jugoistočne Europe koriste Facebook. Koristeći analizu sadržaja, ispitali smo kakve status-poruke gradonačelnici stavljaju na svoje službene Facebook-stranice – privatne ili službene. Osim toga, analizirali smo komentare građana kako bismo utvrdili ostavljaju li građani konstruktivne, cinične, neutralne ili komentare potpore na stranicama gradonačelnika. Ispitano je deset službenih Facebook-stranica gradonačelnika u pet zemalja: Bugarskoj, Hrvatskoj, Mađarskoj, Makedoniji i Sloveniji. Rezultati istraživanja pokazali su da gradonačelnici u navedenim zemljama koriste Facebook gotovo isključivo u službene svrhe. Analiza komentara građana ukazuje kako trend iskazivanja cinizma na Facebooku nije prisutan u zemljama srednje i jugoistočne Europe. Nalazi dalje upućuju na činjenicu da je Facebook dobra platforma za okupljanje simpatizera, ali nisu pronađeni dokazi da Facebook služi kao platforma za konstruktivnu raspravu

Going Offline : How Online Initiatives Revive Offline Civic Engagement

Departing from the concept of the new identity and acknowledging a growing concern about disengaged citizenry, soundly expressed in the accounts of eroding social capital and the crisis of public communication thesis, this paper will develop two assumptions. First, it will argue that online interactions in virtual communities have the potential to create group identity hence providing a source of content that has the capacity to transform virtual into physical communities. Second, it will assume that these virtually created and physical consumed communities have the capacity to induce public action and positively contribute to civic engagement. In order to explore aspects of virtual communities as local e-engagement spaces, this paper will present two case studies – the MoveOn and the Meetup Initiatives

From Who and What to How and Why – The Future of Online Encyclopaedias

This paper discusses changes in the structure of knowledge, the increasing demand for abilities of search and retrieval, assessment and evaluation, organization and creative use of relevant information. It is a review of the topic intended to serve as a basis for further research aimed at answering the many questions that arise from this paper. Today, users are finding content through search engines. This requires a different approach to the organization of encyclopaedias and other lexicographical issues. All can be found, but it is also important to know where and how to look for it. The conducted research centered around the quality of "coverage" of some, in Croatia well known, lexical units, in different Wikipedias: four regional languages and editions (Croatian, Bosnian, Serbian, Serbo-Croatian), and four world languages (English, French, German and Spanish). We observed the presence of writers and athletes in those languages. None of the selected writers had an article in every language/edition. For instance our writers are almost non-existent in Spanish and French editions, and the situation is only slightly better when it comes to German. The representation of athletes was much better, almost all of them occurring in the selected world languages. At the end we come to a few questions, such as whether it is more important to write "for yourself", i.e. to work on creating the best possible encyclopaedia intended for audiences in Croatia, and all those who use the Croatian language, or should we systematically work on the presentation of "our" issues in the publications in other languages; whether it be persons or texts from the sphere of politics, history, or (most widely understood) culture and art. If we agree that we will get relatively successful answers to questions starting with who, what, where, when, and much less successful to those beginning with how or why, then this answers the question on the role of the online encyclopaedia in the transfer of knowledge. The value of the knowledge contained in the answer to the question posed with how or why is "value added" to the encyclopaedia; it is what distinguishes it from a dictionary or a search engine

Viral journalism: The rise of a new form

Current technological and communicational changes introduced with the rise of social media have changed the way the news is created. By using interesting, creative and shareable content in news reporting, such as infographics, polls, videos and memes, the primary goal in news reporting has become the attracting of the user’s attention, and then informing the user. The trend in journalism has become the initiation of the user toward sharing the content – this is why we have introduced a new form of news called viral news. The best example of this kind of journalism is BuzzFeed, a website that has gained huge audience attention and is one of the most popular news sites in the world. In viral news the focus is not on the news narrative, but in the news presentation and distribution. The aim of this paper is to give an insight into this new form of journalism: one that is created to attract attention, that is spreadable via social media and that requires user interaction to fulfi l the news distribution process. This new form of news embraces the dynamics and popularisation of the social media and user’s role in sharing and distributing the content (making it viral), but also creates the interactive, interconnected, emotional, interesting, and immediate content that can gain viral effect. In order to explain and distinguish this form of journalism, the purpose of this paper is to examine “a four quadrant map,” introduced by Boczkowski and Siles, as a life cycle of media technologies. Through four relatively distinct quadrants: production/content, consumption/content, production/ materiality, consumption/materiality, the changes brought by social media and new technologies called ‘viral journalism’ are explained in this article

E-Government and e-Participation : City Web Sites – the Case of Croatia

Relying on the Kang and Gearhart study about the content-specific relationship between citizens' use of city web sites and civic engagement, this study examines the relationship between specific content categories on city Web sites and civic engagement in Croatia. Building upon Kang and Gearhart’s theoretical arguments about motivational communication theories, web site functions, and civic engagement in a new technology context (e.g., Coleman, Lieber, Mendelson, 2008; Jeffres and Lin, 2006; Norris, 2003), this study examined the role of the city web sites in e-participation by surveying citizen users of city web sites. A web based volunteer survey was conducted in 33 Croatian cities, with more than 600 citizens participating. Furthermore, building on Norris’s concept of democratic divide we have content analyzed the web sites of cities that participated in the online survey. The results of content analysis of the city web sites indicate that there is democratic divide (Norris, 2001) in Croatian local government. Secondly, the comparison of the findings obtained by the public opinion web based survey with the results of the content analysis study supports Scott’s (2006) findings about city web sites’ potential for citizens’ civic engagement. Thirdly, the results support Kang and Gearhart’s findings which exhibit a clear indication that city web sites can actively promote civic engagement among citizens. In other words, this study demonstrates that citizens are willing to engage online if the government provides them with an adequate platform

Transparentnost i otvorenost lokalnog javnog upravljanja: slučaj hrvatskih gradova

Transparency and openness are a key concern in contemporary democracies, at both the national and subnational level. Dissemination of public information is a prerequisite for citizens to exercise their individual and political rights. Transparency is also a prerequisite for accountability. The openness of public authorities to a dialogue with the citizenry has become a key ingredient of the democratic process. Citizens are able to take part in a shared responsibility for the decisions of public authorities. The paper presents an evaluation of the websites of 16 Croatian cities. The Transparency and Openness index, composed of four dimensions, and further developed through 13 components, has shown that cities still do not comply with transparency standards, even when those standards are legally prescribed. They are inclined to disclose ‘light’ information, which is not politically loaded and has no direct connection to the accountability mechanism.It is possible, however, to detect innovative leaders, who promote transparency and employ their websites accordingly.Transparentnost i otvorenost je glavna briga suvremenih demokracija, podjednako na nacionalnoj i subnacionalnoj razini. Širenje javnih informacija je preduvjet da bi građani mogli ostvariti svoja pojedinačna i politička prava. Transparentnost je također preduvjet za odgovornost. Otvorenost javnih vlasti dijalogu s građanima postala je ključni sastojak demokratskog procesa. Građani postaju sposobni preuzeti dio odgovornosti za odluke javnih vlasti. U radu se evaluiraju internetske stranice 16 hrvatskih gradova. Indeks transparentnosti i otvorenosti koji se sastoji od četiri dimenzije i 13 komponenti pokazuje da gradovi još nisu dosegli standarde transparentnosti čak i kad su ovi pravno propisani. Gradovi su skloni objavljivati manje važne informacije, koje nemaju političku težinu ni direktnu vezu s mehanizmom političke odgovornosti. Ipak, moguće je pronaći inovativne lokalne vođe koje promoviraju transparentnost i koriste gradske internetske stranice u tu svrhu

EUens: rast novog identiteta potaknut društvenim medijima

The goal of this study is twofold: firstly, we want to explore specific identity that has been emerging as a consequence of many EU-related changes (e.g. development of transport, ICT, increasing number of different EU programs and new EU policies); secondly, we want to test the role of social media in building this new identity that we call EUens (European Union citizens). Conducting in-depth interviews with 25 EUens we find that some issues which are commonly seen as important factors in European identity construction, such as class and political attitudes, do not play any significant role in constructing European identity for members of our group. Secondly, our analysis suggests that social media have potential of becoming important driver of European identity.Cilj je ove studije dvostruk: prvo, želimo istražiti poseban identitet koji se pojavio kao posljedica mnogih promjena povezanih s Europskom unijom (mobilnost, IKT, rastući broj različitih EU programa i novih EU politika); drugo, želimo testirati ulogu društvenih medija u građenju ovog novog identiteta koji mi nazivamo EUens. Provodeći dubinske intervjue s 25 EUensa, pronašli smo kako pojedine kategorije koje su obično smatrane važnim faktorima u građenju europskog identiteta, kao što su klasa i politički stavovi, ne igraju važnu ulogu u građenju europskog identiteta među pripadnicima naše grupe. Drugo, rezultati našeg istraživanja pokazuju kako društveni mediji imaju potencijal da postanu važan pokretač europskog identiteta

Reduction of torque ripple in DTC induction motor drive with discrete voltage vectors

This paper presents а practical implementation of direct torque control (DTC) of an induction machine on MSK2812 DSP platform, and the analysis of possibilities for reduction of torque ripple. Basic theoretical background relating the DTC was primarily set and the obtained experimental results have been given. It is shown that the torque ripple can be reduced by adjusting the intensity of voltage vectors and by modification of hysteresis comparator, while the simplicity of the basic DTC algorithm has been maintained. [Projekat Ministarstva nauke Republike Srbije, br. TR33016

The role of artificial intelligence in media content creation

Digitalizacija i razvoj alata umjetne inteligencije (AI) doveli su do revolucije u brojnim sferama, a posebice u komunikaciji. I dok su medijske sadržaje prije isključivo stvarali pojedinci, danas postoje različiti jezični, slikovni, glasovni i videoalati koji s lakoćom formiraju sadržaj spreman za distribuciju i konzumaciju. AI, kao takav, već sada znatno transformira medije i komunikaciju, a razvojem tehnologije doći će i do novih promjena u stvaranju medijskog sadržaja. Iako je tema umjetne inteligencije sve više u središtu znanstvenih istraživanja, utvrđen je nedostatak literature na hrvatskom jeziku koja sažima glavne odrednice o ulozi umjetne inteligencije u stvaranju medijskog sadržaja. Ovaj rad stoga na hrvatskom jeziku donosi pregled stanja u području te nudi perspektive za buduću implementaciju umjetne inteligencije u kontekstu kreiranja sadržaja i komuniciranja na društvenim medijima.Digitization and the development of artificial intelligence tools have revolutionized numerous spheres, particularly in communication. While media content was previously exclusively created by individuals, today there are various linguistic, visual, voice, and video tools that effortlessly generate content ready for distribution and consumption. AI, as such, is already significantly transforming media and communication, and with the advancement of technology, further changes in media content creation will arise. Although the topic of artificial intelligence is increasingly the focus of scientific research, there is a lack of literature in Croatian that summarizes the main aspects of the role of artificial intelligence in media content creation. This paper, therefore, provides an overview of the field and offers perspectives for future implementation of artificial intelligence in the context of content creation and communication on social media